EA024187B1 - Process for the manufacture of at least one ethylene derivative compound - Google Patents

Abstract

Process for the manufacture of at least one ethylene derivative compound starting from a low value residual gas according to which: a) the low value residual gas, optionally containing fraction E1 recycled from step d), is subjected to a series of treatment steps in a low value residual gas recovery unit in order to remove the undesirable components present therein and to obtain a mixture of products containing ethylene and other constituents; b) the said mixture of products is subjected to a first separation step S1 which consists of separating said products containing ethylene and other constituents into a fraction containing the compounds which are lighter than ethylene and part of the ethylene called fraction F1 and into a fraction F2; c) fraction F1 is sent to an ethylene recovery unit in which it is separated into a fraction enriched with ethylene called fraction E1 and into a fraction enriched with the compounds which are lighter than ethylene called light fraction; d) fraction E1 is recycled to step a) or is conveyed to the manufacture of at least one ethylene derivative compound; e) fraction F2 is subjected to a second separation step S2 which consists of separating fraction F2 into one fraction enriched with ethylene called fraction E2 or into two fractions enriched with ethylene called fractions E2a and E2b, and into a fraction enriched with ethane and hydrocarbon containing at least 3 carbon atoms called heavy fraction; f) fraction E2 or fractions E2a and E2b are then conveyed to the manufacture of at least one ethylene derivative compound.

Description

The present invention relates to a method for producing at least one ethylene derivative, in particular, a method for producing 1,2-dichloroethane (ECE) and at least one ethylene derivative, which is obtained directly from ethylene and which differs from ECE.

Until now, ethylene, which has a purity of more than 99.8%, is usually used to produce ethylene derivatives, in particular EfE. This ethylene with very high purity is obtained by cracking various petroleum products, followed by numerous complicated and expensive separation operations to separate ethylene from other cracking products and to obtain a product with very high purity.

Due to the high prices associated with the production of ethylene with such high purity, various methods have been developed to obtain ethylene derivatives, in particular, ECE. using ethylene having a purity less than 99.8%. These methods have the advantage of reducing the cost by simplifying the process of separating the products resulting from cracking, and, thus, avoiding complex separations that are disadvantageous for obtaining ethylene derivatives, in particular, ESE.

For example, patent application νθ 00/26164 describes a method for producing ECE by simplified cracking of ethane in combination with ethylene chlorination. To this end, the chlorination of ethylene is carried out in the presence of impurities formed during the cracking of ethane.

The patent application νθ 03/048088 describes the production of ethylene with a low concentration for a chemical reaction with chlorine through the dehydrogenation of ethane. The gas stream loaded with ethane contains not only hydrogen and methane, but also large quantities of unconverted ethane. To develop an economical process, unconverted ethane should be sent back to ethane dehydrogenation after the purification process is completed. In this process, only ethane can be used as a raw material. A significant disadvantage is the very low concentration of ethylene - less than 60%, as well as the fact that additional components of the gas stream, such as hydrogen, propylene, butadiene, make it possible to use ethylene only in very special ways.

Further, in patent applications νθ 2006/067188, νθ 2006/067190, νθ 2006/067191, νθ 2006/067192, νθ 2006/067193 and νθ 2007/147870 described methods for producing ESC from a hydrocarbon source, in particular from naphtha, gas oil, a liquid portion of natural gas, ethane, propane, butane, isobutane, or a mixture thereof, which is first subjected to simplified cracking. In patent applications νθ 2008/000705, νθ 2008/000702 and νθ 2008/000693 described, as part of them, methods for producing ECE from an ethane stream, which is first subjected to catalytic oxidation. The methods described in the above patent applications, the purpose of which is to obtain and use ethylene having a purity of less than 99.8%, have, however, disadvantages the need for a first cracking stage or catalytic oxidation, which requires a significant investment, causing an increase in the production cost, and the addition of an expensive hydrocarbon source.

Low-value residual gases, such as refinery or refinery exhaust gases (also called petrochemical residual gases), produced at refineries and refineries (in catalytic cracking units with fluidized catalyst (PCC), coking plants, etc.) refineries and refineries) are usually burned and used as fuel, for example, at a refinery or refinery, without any utilization and olefins contained therein, as olefin content is relatively low and the cost associated with such a separation method, is too high.

One method, the purpose of which is to obtain and use ethylene having a purity of less than 99.8%, as well as the valorization of such low-value residual gases, is described in patent application νθ 2009/106479. This method is a method of obtaining at least one ethylene derivative of such gases, which are subjected to separation into two different fractions containing ethylene; the first fraction containing part of ethylene, which is enriched in a compound lighter than ethylene, and the second fraction, which is enriched in ethylene and has a low hydrogen content. These two ethylene fractions are then separately transferred to obtain at least one ethylene derivative.

The method described in this patent application, however, has the disadvantage of requiring separation of ethylene into two fractions, which have a different composition. Another disadvantage is that the conditions of use of these two fractions are different, which may interfere with the ways in which they are then used. In addition, some applications are unacceptable due to the two qualities of ethylene, which consist in the reactivity of the impurities they contain; for example, hydrogen, which is unacceptable in the oxychlorination process of ethylene. Another disadvantage is that the very high content of compounds that are lighter than ethylene in the ethylene fraction implies an increase in the size of the equipment used and contributes to the increase in losses through the stripping, which makes the method less effective. Finally, the valorization of the ethylene fraction containing compounds lighter than ethylene is a more difficult task.

- 1024187 because it depends on the pressure and temperature at the outlet of the installations in which it is used.

The objective of the present invention for its part is to provide a method for producing at least one ethylene derivative, in particular, at least ESE. using ethylene with a purity of less than 99.8%, which does not have the disadvantages of the above methods using ethylene, having a purity of less than 99.8%, which additionally allows the valorization of low-value residual gases, such as cleaning residual gases, and in addition , allows you to valorize compounds that are lighter than ethylene, to carry out the operation in installations with injection flow with higher flexibility, and also allows you to save money when operating these installations with injection flow .

Accordingly, the invention relates to a method for producing at least one ethylene derivative from a low-value residual gas, according to which:

a) residual low value gas, optionally containing fraction E1 recycled from stage ά), is subjected to a number of processing steps in a low-value residual gas utilization unit to remove unwanted components present in it and to obtain a mixture of products containing ethylene and other components;

b) the specified mixture of products is subjected to the first stage of separation 81, which consists of separating said products containing ethylene and other components into a fraction containing compounds that are lighter than ethylene, and part of ethylene, and called fraction P1, and into a fraction P2;

c) the P1 fraction is sent to the ethylene separation unit, in which it is divided into a fraction enriched in ethylene and called the E1 fraction, and a fraction enriched in compounds that are lighter than ethylene and called the light fraction;

ά) the E1 fraction is recycled to step a) or sent to obtain at least one ethylene derivative;

e) the P2 fraction is subjected to the second stage of separation 82, which consists of dividing the P2 fraction into one fraction enriched in ethylene and called fraction E2, or into two fractions enriched in ethylene and called fractions Е2а and Е2Ь, and into a fraction enriched in ethane and hydrocarbon, containing at least 3 carbon atoms, and named the heavy fraction;

1) Fraction E2 or Fractions E2a and E2b are then sent to obtain at least one ethylene derivative.

It is assumed that the expression at least one ethylene derivative means for the purpose of the present invention that one or more ethylene derivatives can be obtained by the method according to the present invention.

It is assumed that the expression derived ethylene, used later in the singular or plural, means for the purpose of the present invention any derivative of ethylene, obtained directly from ethylene, as well as any compound derived from it.

It is assumed that the expression derived ethylene, obtained directly from ethylene, used later in the singular or plural, means for the purpose of the present invention any compound obtained directly from ethylene.

It is assumed that the expression compound obtained from it, used later in the singular or plural, means for the purpose of the present invention any compound obtained from a single compound that is itself obtained from ethylene, as well as any compound derived from it.

As examples of such ethylene derivatives obtained directly from ethylene, among others, ethylene oxide, unbranched alpha-olefins, unbranched primary alcohols, homopolymers and copolymers of ethylene, ethylbenzene, vinyl acetate, acetaldehyde, ethyl alcohol, propionaldehyde and OSE can be mentioned.

As examples of such a compound obtained from an ethylene derivative, among others are glycols and ethers derived from ethylene oxide, styrene obtained from ethyl benzene, and styrene polymers derived from styrene; vinyl chloride (CD) derived from EfE, vinylidene chloride, fluorinated hydrocarbons and polyvinyl chloride (PVC), obtained from CD, and fluorinated polymers obtained from fluorinated hydrocarbons, as well as polyvinylidene chloride and fluorinated hydrocarbons (and fluorinated polymers) obtained from vinylidene chloride.

The method according to the invention is a method based on the use of a residual gas of low value.

It is assumed that the expression low value residual gas (LUK.0), used later in the singular, means for the purpose of the present invention one gas or a mixture of several gases,

- 2,024,187 containing ethylene and / or its precursor (s), which are waste gases, obtained as a by-product in installations, the purpose of which is to obtain at least one combustible liquid; the LURS contains more than 10% by weight of a constant gas.

The expression gas is to be understood for the purpose of the present invention in the sense of the definition given by ΝΡΡΑ69 Shapbatb op Εχίίδδοο Р RevueSchüp §u51et5, 1997 Εάίΐίοη, i.e. state of matter, characterized by full molecular mobility and unlimited expansion.

The expression precursor is intended to mean for the purpose of the present invention any hydrocarbon compounds containing two carbon atoms other than ethylene, in particular ethane, ethanol and acetylene, more specifically ethane and acetylene.

The expression combustible liquid is assumed to mean for the purpose of the present invention any hydrocarbon fraction containing atoms of carbon, hydrogen and possibly oxygen which is at least partially liquid at 21 ° C at its loading pressure and which is capable of undergoing combustion.

The expression burning is to be understood for the purpose of the present invention in the sense of the definition given by ΝΕΡΆ69 Shapbatb op Εχίίδδοο RegeSeup 8u§1et5, 1997 οη, i.e. a chemical oxidation process that takes place at a rate fast enough to produce heat and usually light, in the form of either glow or flame.

The expression constant gas is assumed to mean, for the purpose of the present invention, any gas whose critical temperature is lower than 0 ° C and which cannot be liquefied by simple compression. Examples of constant gases are hydrogen, oxygen, nitrogen, helium, argon, carbon monoxide and methane.

LURS can be obtained in at least one type of unit that processes hydrocarbon sources to produce combustible liquids. Such installations can be installations of pyrolysis of hydrocarbon sources, hydropyrolysis, catalytic pyrolysis, electric pyrolysis of AGE, Fischer-Tropsch synthesis or refining of oil and oil products. Hydrocarbon sources can be solid sources like coal, lignite and wood, liquid sources like oil products (oil), and naphtha or gaseous sources like synthesis gas or residual gas from oil and / or gas fields. Such BURS is usually burned as a fuel or flared.

It is assumed that the expression at least one type of hydrocarbon source processing units means, for the purpose of the present invention, that LURS can be obtained in one type of hydrocarbon source processing units or in several types of hydrocarbon source processing units. Preferably, LURS is produced in one type of hydrocarbon source processing unit.

LURS is predominantly under pressure, above atmospheric pressure, and preferably at a pressure between atmospheric pressure and pressure of the installation in which it is produced.

The LURS, which is particularly preferred for the method according to the present invention, is the LURS obtained at refineries for petroleum and petroleum products, commonly referred to as flue gas from refineries for petroleum and petroleum products (also called petrochemical flue gas) and hereinafter referred to as POC.

Therefore, the method according to the invention is preferably a method based on the use of POC.

DEW can be produced in one or several plants available at refineries for refining oil and petroleum products. DFW is preferably obtained in at least one of the following facilities available at refineries for refining oil and oil products: liquid catalytic cracking plants (PCC), coking plants (coking operation, liquid-phase coking, coking under mild conditions), an installation for the gasification of fuel, a reforming unit, a hydrocracking unit, a hydrotreating unit and a hydrogeological unit desulfurization (ΗΌ8). More preferably, POC is obtained in at least one PCC unit.

DEW can be produced at one or more refineries or refineries.

Most preferably, POC is obtained at one refinery or oil refinery, with particular preference, at a single PCC unit.

The LURS, preferably POC, may especially contain some of the compounds listed below. The LURS, preferably POC, usually contains the compounds listed below:

hydrogen, methane, ethane, ethylene, propane, propylene, hydrocarbons containing 4, 5 or 6 carbon atoms, higher molecular weight hydrocarbons with C6 + and hydrogen sulfide;

nitrogen, argon, helium, carbon dioxide and water; oxygen, carbon monoxide and nitrogen oxides;

hydrogen chloride, hydrogen cyanide, ammonia, nitrides, nitriles, carbonyl sulfide, organic compounds containing one sulfur atom per molecule, like mercaptans and sulfides;

- 3,024,187 organic compounds containing more than one sulfur atom, like disulfides, sulfur oxides, acetylene, propadiene, methylacetylene, butadiene, diethanolamine, methanol, phosphines, other inorganic compounds containing chlorine, and organic compounds containing nitrogen; and arsenic (similar to arsines), mercury, vanadium, bromine, fluorine, silicon, aluminum and metal carbonyls.

All of the above components, with the exception of ethylene, can be listed as undesirable components. The expression undesirable components is intended to mean for the purpose of the present invention all components that are at least partially removed if they are harmful for at least one of the following method steps.

These undesirable components can be classified especially as follows: combustible gases like hydrogen, methane, ethane, propane, hydrocarbons containing 4, 5 or 6 carbon atoms, higher molecular weight hydrocarbons with C6 +; inert gases like nitrogen, helium and argon; oxidized compounds like oxygen and nitrogen oxides;

corrosive compounds like carbon dioxide, hydrogen sulfide, water, hydrogen chloride, hydrogen cyanide, ammonia, nitrides, nitriles, carbonyl sulfide, organic compounds containing one sulfur atom per molecule, like mercaptans and sulfides, and sulfur oxides;

reactive compounds like propylene, acetylene, propadiene, methylacetylene, butadiene, diethanolamine, methanol, phosphines, other inorganic compounds containing chlorine, organic compounds containing nitrogen, organic compounds containing more than one sulfur atom per molecule, disulfide-like, and carbon monoxide; and catalyst poisoning compounds like arsenic compounds (like arsines), mercury, vanadium, bromine, fluorine, silicon, aluminum, and metal carbonyls.

These undesirable components can also be classified especially as follows:

1) undesirable components that may be harmful at least for stage b) and which are essentially substantially removed during stage a), i.e. corrosive compounds like carbon dioxide, hydrogen sulfide, water, hydrogen chloride, hydrogen cyanide, ammonia, nitrides, nitriles, carbonyl sulfide, organic compounds containing one sulfur atom per molecule, like mercaptans and sulfides, and sulfur oxides; and catalyst poisoning compounds like arsenic compounds (like arsines), mercury, vanadium, bromine, fluorine, silicon, aluminum, and metal carbonyls;

2) undesirable components that may be acceptable in stage b) and subsequent stages, but which may be harmful for at least one of the stages of the method after stage e) and which can be at least partially removed during stage a), t. e.

combustible gases like hydrogen, methane, ethane, propane, hydrocarbons containing 4, 5 or 6 carbon atoms, higher molecular weight hydrocarbons with C6 +;

inert gases like nitrogen, helium and argon; oxidized compounds like oxygen and nitrogen oxides;

reactive compounds like propylene, acetylene, propadiene, methylacetylene, butadiene, diethanolamine, methanol, phosphines, other inorganic compounds containing chlorine, organic compounds containing nitrogen, organic compounds containing more than one sulfur atom per molecule, disulfide-like, and carbon monoxide.

It is assumed that the expression at least partially removed means for the purpose of the present invention that advantageously at least 25%, preferably at least 40%, more preferably at least 50% of the amount of each undesirable component present in LUCS, preferably CBS, directed on stage a) and / or formed during stage a), is removed. Preferably, at most 90% of the amount of each such undesirable component present in the BLX, preferably the BEC directed to step a) and / or formed during step a), is removed.

It is assumed that the expression essentially removes means, for the purposes of the present invention, that advantageously at least 95%, preferably at least 98%, more preferably at least 99% of the amount of each undesirable component present in LUCS, preferably CBS, sent to stage a) and / or formed during stage a) is removed.

The compositions that are listed below for LUX, preferably KOS, are based on dry gas (water not included). As indicated above, LUCS, preferably CBS, may be a single gas or a mixture of several gases that comprise a LUX, containing ethylene and / or its precursor (s). The compositions that are listed below, when they belong to an individual LUX, preferably KOS, correspond to the case where LUX, preferably KOS, is a single gas containing ethylene and / or its precursor (s). With regard to the combined HUKS, preferably KOS, the compositions correspond to the case when LUKS, preferably KOS, is a mixture of several gases,

- 4 024187 containing ethylene and / or its predecessor (s).

The individual LPX, preferably CBS, contains predominantly from 0.25 to 60% by weight of ethylene. LUCS, preferably CBS, preferably contains at least 0.25, preferably at least 2, more preferably at least 5, most preferably at least 8 and particularly preferably at least 10% by weight of ethylene. UX, preferably CBS, contains predominantly at most 60, preferably at most 55, more preferably at most 50 and most preferably at most 48% by weight of ethylene.

Combined LUCS, preferably CBS, contains predominantly from 10 to 60 wt.% Of ethylene. UX, preferably CBS, contains predominantly at least 10%, preferably at least 15, more preferably at least 18% and most preferably at least 20% by weight of ethylene. UX, preferably CBS, contains predominantly at most 60, preferably at most 55, more preferably at most 50 and most preferably at most 48% by weight of ethylene.

The individual LPX, preferably CBS, contains predominantly from 3 to 60% by weight of ethylene plus its predecessor (s). UX, preferably CBS, contains predominantly at least 3, more preferably at least 5, more preferably at least 8 and most preferably at least 10% by weight of ethylene plus the precursor (s). UX, preferably CBS, contains predominantly at most 60, preferably at most 55, more preferably at most 50 and most preferably at most 48% by weight of ethylene plus the precursor (s).

The combined BUCS, preferably CBS, contains predominantly from 10 to 60% by weight of ethylene plus the precursor (s). LUCS, preferably CBS, contains predominantly at least 10%, preferably at least 15%, more preferably at least 20%, most preferably at least 22% and even most preferably at least 22.5% by weight of ethylene plus predecessor (s). UX, preferably CBS, contains predominantly at most 60, preferably at most 55, more preferably at most 50 and most preferably at most 48% by weight of ethylene plus the precursor (s).

Individual HPC, preferably CBS, is characterized by a lower calorific value, predominantly 10-90 MJ / kg dry gas. Individual COX, preferably COB, has a lower calorific value, preferably at least 10, preferably at least 12, and more preferably at least 15 MJ / kg dry gas. The individual LPX, preferably CBS, is characterized by a lower calorific value, preferably of at most 90, preferably at most 85 and more preferably at most 80 MJ / kg of dry gas.

Combined LUKS, preferably KOS, is characterized by a lower calorific value, mainly constituting 20-75 MJ / kg of dry gas.

LUCS, preferably CBS, is characterized by a lower calorific value, preferably at least 20, preferably at least 25, more preferably at least 30 and most preferably at least 35 MJ / kg dry gas. UX, preferably BEC, has a lower calorific value, preferably at most 75, preferably at most 70, more preferably at most 60 and most preferably at most 55 MJ / kg dry gas.

The individual LCS, preferably CBS, contains preferably at most 90, preferably at most 85, more preferably at most 80 and most preferably at most 75% by volume. inert gases.

The combined LUCS, preferably CBS, contains preferably at most 25, preferably at most 20, more preferably at most 18 and most preferably at most 15% by volume of inert gases.

The combined LUCS, preferably CBS, contains preferably at most 25, preferably at most 20, more preferably at most 18 and most preferably at most 15% by volume of nitrogen.

Individual LPX, preferably CBS, contains oxidized compounds in a total amount that is predominantly lower or higher than the level necessary to impart flammability of the gaseous mixture (thus, outside the flammability limit), preferably at most 21, more preferably at most 18 and most preferably at most 15 vol.%.

The combined BUCK, preferably CBS, contains oxidized compounds in a total amount that is preferably lower than the level necessary to make the gaseous mixture flammable, preferably at most 10, more preferably at most 7, and most preferably at most 5% by volume.

The combined LUCS, preferably CBS, contains oxygen in an amount of preferably at most 9, preferably at most 7, and more preferably at most 5

- 5,024187% by volume.

The individual LCS, preferably CBS, contains corrosive compounds in a total amount of preferably at most 50, preferably at most 40, and more preferably at most 35% by volume.

The combined LUCS, preferably CBS, contains corrosive compounds in a total amount of preferably at most 20, preferably at most 15 and more preferably at most 10% by volume.

The combined LUCS, preferably CBS, contains each corrosive compound in an individual amount of preferably at most 10, preferably at most 8, and more preferably at most 5 vol.%.

The individual LCS, preferably CBS, contains reactive compounds in a total amount of preferably at most 40, preferably at most 35 and more preferably at most 33% by volume.

The combined LUCS, preferably CBS, contains reactive compounds in a total amount of preferably at most 20, preferably at most 18 and more preferably at most 15% by volume.

The combined LUCS, preferably CBS, contains each reactive compound in an individual amount of preferably at most 15, preferably at most 12, and more preferably at most 10% by volume.

The combined LUCS, preferably CBS, contains carbon monoxide in an amount of preferably at most 5, preferably at most 3 and more preferably at most 2% by volume.

The individual LPX, preferably CBS, contains compounds that poison the catalyst, in a total amount of preferably at most 200, preferably at most 100 and more preferably at most 50 ppm by volume.

The combined LUCS, preferably CBS, contains compounds that poison the catalyst, in a total amount of preferably at most 5, preferably at most 2 and more preferably at most 1 ppm by volume.

The combined LUCS, preferably CBS, contains compounds that poison the catalyst, the volume of each of which is preferably at most 500, preferably at most 300 and more preferably at most 200 parts by volume per billion.

In a method for producing at least one ethylene derivative, in particular in a method for producing ISE and at least one ethylene derivative, which is obtained directly from ethylene and which differs from ISE, from LUCS, preferably CBS, according to the present invention, LUCS, preferably CBS, optionally containing fraction E1 recirculated from stage b), is subjected to a series of processing steps (stage a)) in a LUCS disposal plant, preferably KOS, to remove unwanted components present in it and for radiation products containing ethylene and other components, which will be subjected to stage b).

When LVX, preferably CBS, is a mixture of several gases, all different gases can be subjected to the same series of processing steps in stage a), each of them can be subjected to a special series of processing stages in stage a) or each of them can be subjected to combinations of a special series of processing stages and the usual series of processing steps in stage a). Each of them is preferably subjected to a combination of a special series of processing steps and the usual series of processing steps in stage a).

The series of processing steps in the LUCS disposal unit, preferably CBS, in stage a) mainly consists of the following stages, which are not necessarily carried out in the order in which they are listed:

a1) an optional compression stage, a1bis) optionally one or more special stages, a2) removal of corrosive compounds, a3) removal of compounds poisoning the catalyst, a4) optional cooling, a5) optional, at least partially removing some combustible gases, a6) an optional, at least partial removal of a certain amount of inert gases, a7) an optional, at least partial removal of a certain amount of oxidized compounds, and a8) optional, m To a lesser extent, partial removal of a certain amount of reactive compounds.

Optionally, a compression step is carried out (step a1). Preferably, a compression step is carried out (step a1).

When applied, the compression stage of the LUX, preferably CBS, advantageously increases

- 6,024,187 pressure at least up to 8, preferably at least up to 10, more preferably at least up to 12 and most preferably at least up to 14 kg / cm ^{2 -} g and preferably at most up to 60, preferably at most up to 55 more preferably up to at most 50 and most preferably up to at most 45 kg / cm ² -g.

Stage A1) is preferably carried out in several stages, either in a multi-stage gas compressor, or in several gas compressors. Separation of the droplets is preferably carried out before the compression step a1).

The degree of compression at each stage of compression is such that the temperature at the exit of the compression stage is preferably at most 150, preferably at most 120 and more preferably at most 100 ° C. The gas that leaves this stage is then preferably cooled by indirect cooling by cooling media. The cooling media are preferably selected from the water of the tower cooler, cold water, atmospheric air and cold gas obtained as a result of this method. The cooling medium is preferably selected from the water of the tower cooler and atmospheric air. The cooling liquid is more preferably the water of the tower cooler.

The gas is preferably cooled below 50, preferably below 48 and more preferably below 45 ° C, but preferably not below 0, preferably not below 5 and more preferably not below 10 ° C.

At the end of the cooling, some condensates may form. If some amounts of condensate are formed, they can be separated or not separated. Preferably they are separated. Condensates are predominantly degassed by depressurizing; pressure is preferably released at the pressure of the upstream stage. The stripping of separated liquids can be carried out to isolate volatile fractions. The resulting gas is more preferably recycled with the gases of the upstream step.

The solids present in the gas or generated in any of the pretreatment steps may optionally be separated by a suitable operation, i.e. one or more special stages (special stage (s) a1bis)). From suitable operations, you can specify, for example, gravitational sedimentation, collision, cyclone application, filtering, electrofiltration and / or electrical deposition. Preferred is the use of cyclone, filtration and electrofiltration.

The removal of corrosive compounds (stage a2)) can be carried out in one or more groups of stages, each containing one or several stages.

The first group of stages (stages a2a)) contains mainly one or several stages of absorption.

Absorption is preferably absorption by a regenerable solution like an amine solution (preferably alkanolamine), physical absorption with a suitable solvent like methanol or dimethyl ether of polyethylene glycol, or absorption by a chemical reaction carried out by gas cleaning in an alkaline solution.

The alkali is preferably a hydroxide, oxide or carbonate. Examples of alkalis are sodium hydroxide, potassium hydroxide, calcium oxide, magnesium oxide, sodium carbonate, and potassium carbonate.

The removal of the corrosive compounds by absorption (steps a2a)) preferably contains the first stage, which is absorption by a regenerable solution of an amine, preferably alkanolamine, followed by absorption by an alkaline solution (column for washing with alkali / water), preferably sodium hydroxide solution.

The regenerated solution can be regenerated or not regenerated. If regeneration takes place, it is carried out mainly in one or several stages, especially for the separation of carbon dioxide and hydrogen sulphide. The regenerated solution is preferably regenerated and more preferably regenerated in two stages.

The removal of the corrosive compounds by absorption (steps a2a) more preferably contains the first stage, which is the absorption of a regenerable solution of an amine, preferably alkanolamine, which is regenerated in two stages, followed by absorption with an alkaline solution (alkali / water washing column), preferably sodium hydroxide solution.

Corrosive compounds that can be at least partially removed by such steps a2a) are predominantly hydrogen sulfide, hydrogen chloride, carbonyl sulfide, hydrogen cyanide, carbon dioxide, ammonia, and organic compounds containing one sulfur atom per molecule, like mercaptans and sulfides .

Alternatively, organic compounds containing one sulfur atom per molecule, like mercaptans and sulfides, ammonia, and sulfur oxides, can be at least partially hydrolyzed during steps a2a).

Water can also be at least partially removed by such steps a2a), especially if a physical sorbent, like methanol, is used.

- 7 024187

The second group of stages (stages a2b)) contains mainly one or several stages of hydrogenation.

Hydrogenation of corrosive compounds, such as, for example, hydrogen cyanide, nitrides, nitriles, carbonyl sulfide, organic compounds containing one sulfur atom per molecule, like mercaptans and sulfides, and sulfur oxides, are preferably carried out in a hydrogenation reactor using a hydrogenation catalyst. After stages a2b), hydrogen cyanide, nitrides, nitriles, carbonyl sulfide, organic compounds containing one sulfur atom per molecule, like mercaptans and sulfides, and also sulfur oxides are predominantly at least partially hydrogenated.

Suitable types of catalysts include predominantly metals of group VIII, metals of group 1b and metals of group νίΚ. Preferred are catalysts based on palladium, nickel or gold. More preferred are palladium or nickel based catalysts. Most preferred are nickel-based catalysts with particular preference given to sulphided nickel type catalysts. Hydrogenation catalysts can be supported or unsupported. Preferably they are applied on a carrier. Catalysts such as those mentioned for step a7) can also be used.

If carbonyl sulphide is still present in the hydrogenation feedstock, it is preferably converted, at least partially, to mercaptans during the a2b) hydrogenation steps, preferably with a palladium or nickel based catalyst, more preferably with a sulfided nickel catalyst.

The nitriles present in the hydrogenation feedstock are also advantageously at least partially converted, preferably using a palladium or nickel based catalyst, more preferably a sulfided nickel catalyst, into amines during the a2b) hydrogenation steps.

If hydrogen cyanide is still present in the hydrogenation feedstock, it is predominantly at least partially removed during the hydrogenation steps of a2b), preferably with the use of a palladium or nickel based catalyst, more preferably a sulfided nickel catalyst.

Stages a2b) are preferably carried out at a temperature between 25 and 100 ° C.

The third group of stages (stages a2c)) contains mainly one or several stages of cooling.

Cooling is preferably carried out directly or indirectly by cooling with a cooling medium. Direct cooling means physically contacting the process stream with cooling media. Examples of suitable cooling media for direct contact cooling are water, methanol, hydrocarbon, or a mixture thereof. Another example of suitable cooling media is an aqueous solution of an alkanolamine, a metal carbonate or bicarbonate, an inorganic acid like sulfuric acid or nitric acid. Another example of suitable media is a methanol solution of an alkanolamine or metal carbonate or bicarbonate. The temperature of the cooling medium is preferably lower than the temperature of the stream. Cooling is preferably carried out by direct cooling with cooling media. The cooling medium is preferably chosen from the water of the tower cooler, cold water, atmospheric air and cold gas obtained as a result of this method. The cooling medium is preferably selected from the water of the tower cooler and atmospheric air. The cooling liquid is more preferably the water of the tower cooler.

The gas is preferably cooled below 50, preferably below 48 and more preferably below 45 ° C, but preferably not below 0, preferably not below 5 and more preferably not below 10 ° C. Alternatively, a drying step at a temperature below the freezing point may be used for drying.

Condensates can be separated or not separated. They are preferably separated.

The fourth group of stages (stages a2f) contains mainly one or several stages of adsorption.

Adsorption is advantageously adsorption on a suitable solid, like activated carbon, charcoal, molecular sieve, zeolite, silica gel or alumina.

The adsorption of water is preferably carried out, at least in part, by a stage of adsorption on a molecular sieve, silica gel or alumina.

The removal of water, at least in part, is preferably carried out by a combination of cooling (stage a2c)) and adsorption (stage a2f).

Mercaptans formed from carbonyl sulphide, carbonyl sulphide, as well as sulphides, are advantageously at least partially removed by adsorption of a suitable substance in the layer. Suitable adsorbents include preferably a carbonaceous substance, such as activated carbon and especially activated carbon, having a specific surface area between 500 and 2500 m ² / g, molecular sieve 3A, 4A or 13X, zeolite, mesoporous adsorbent, including activated alumina such as mesoporous activated alumina with BET specific surface between 150 and 800 m ² / g, silica gel, mesoporous silica gel, adsorbent with BET specific surface between 150 and 800 m ² / g, type A zeolite, type 5A zeolite, fouzite type zeolite and X, foyazite-type zeolite and zeolite ΜΡΙ. Preferred are activated carbon, molecular sieve 3 or 4A and activated alumina.

Amines formed from nitriles, as well as residual nitriles, are advantageously at least partially removed by adsorption with the same type of adsorbents as adsorbents for the removal of mercaptans. Nitrides can also be at least partially adsorbed during stages a2).

Ammonia is also advantageously at least partially removed by adsorption with the same type of adsorbents as adsorbents for removing mercaptans, if not already removed.

Carbon dioxide, if not removed during steps a2a), can also advantageously, at least partially, be removed by adsorption on a suitable adsorbent. Suitable adsorbents include activated copper, mineral clay, silica gel and activated alumina.

The removal of compounds that poison the catalyst (stage a3)) can be carried out in one or several groups of stages, each group containing one or several stages.

The first group of stages (stages a3a) contains mainly one or several stages of adsorption.

Adsorption is preferably chemical or physical adsorption on a suitable solid, like activated carbon, charcoal, molecular sieve, zeolite, or alumina, which is activated or inactive.

Compounds that poison a catalyst are preferably at least partially removed by chemical or physical adsorption on alumina, preferably activated, or on activated carbon.

Adsorption is preferably used at least 1, preferably at least 2 adsorbents. For absorption, preferably at most 6, preferably at most 5, more preferably at most 4 adsorbents are used. Most preferably used 3 adsorbent.

The gas flow can be contacted with solid adsorbents in any suitable device. Pneumatic transporting moving beds and fixed beds can be specified as suitable devices. Fixed layers are preferred.

Adsorbents can be placed in mixed layers or in special layers. They can be placed in a single vessel or in separate vessels. The adsorbents are preferably placed in special layers, more preferably in 3 special layers and preferably in separate vessels.

Each stage of adsorption can be carried out in one or several parallel layers. Each adsorption step is preferably carried out in several parallel layers, more preferably in at least two separate layers.

Regeneration can be carried out in the device itself or outside the device. Regeneration is preferably carried out in the apparatus itself.

The second group of stages (stages a3b)) contains mainly one or several stages of absorption.

Absorption is preferably physical absorption, for example, a suitable solvent, like polyethylene glycol dimethyl ether or methanol, or chemical absorption, for example, an aqueous alkaline solution, described for steps a2a).

Stage A3) is mainly carried out at a temperature between 25 and 100 ° C.

In addition to stages a2c), the cooling stage is not necessarily carried out (stage a4)). Stage A4) is preferably carried out mainly by direct cooling with cooling media.

A number of processing stages (stage a) therefore advantageously comprise at least a compression stage (stage a1)) and a stage of cooling (stage a4)).

Cooling media are preferably selected from the water of a tower cooler, cold water, a hydrocarbon such as ethylene, ethane, propylene, propane, or a mixture of two or more of these hydrocarbons, CO ₂ , hydrofluorocarbon refrigerant, atmospheric air, and the cold gas produced by this process. Cooling media are preferably selected from the water of a tower cooler, a hydrocarbon, such as ethylene, ethane, propylene, propane, or a mixture of two or more such hydrocarbons, or cold gas, produced as a result of this process, or atmospheric air. The cooling liquid is more preferably water from a tower cooler or a hydrocarbon such as ethylene, ethane, propylene, propane, or a mixture of two or more such hydrocarbons, or cold gas resulting from this process.

The gas is preferably cooled below 0, preferably below -10 ° C and more preferably

- 9 024187 below -20 ° C, but preferably not lower than -150 ° C, preferably not lower than -120 ° C and more preferably not lower than -100 ° C.

Condensates can be separated or not separated. They are preferably separated.

Optional, at least partially removing some of the combustible gases (step a5)).

At least a portion of the hydrogen and / or methane can be at least partially removed (step a5a)). This removal is optionally carried out during step a) of the process according to the invention. Such a step of removing at least a portion of the hydrogen and / or methane can also be carried out during step b) of the process according to the invention, for example, during the separation of a mixture of products obtained from step a) or from fractions E2, E2a or E2b. When carrying out the removal of at least part of the hydrogen and / or methane, such removal is preferably carried out during stage a) (stage a5a)) of the method according to the invention.

Suitable stages for the separation of hydrogen and / or methane are mainly membrane permeation and adsorption with pressure fluctuations (ΡδΑ). ΡδΑ is preferred.

At least part of ethane, propane and / or hydrocarbons containing 4, 5 or 6 carbon atoms, or more high-molecular hydrocarbons with C6 + can be at least partially removed (stage a5b)) mainly in several stages.

This removal is optionally carried out during step a) of the process according to the invention. Such a step of removing at least a portion of ethane, propane and / or hydrocarbons containing 4, 5 or 6 carbon atoms, or more high molecular weight C6 + hydrocarbons can also be carried out during step b) of the process according to the invention, for example, during the separation of a mixture of products, obtained from stage a).

A suitable stage for the separation of ethane, propane and / or hydrocarbons containing 4, 5 or 6 carbon atoms, or higher molecular weight hydrocarbons with C6 + is preferably condensation. Stage a5b) is preferably combined with a compression stage a1) and / or cooling stages a2c) and / or a4).

Optionally, at least a partial removal of some inert gases is carried out (step a6)).

This removal is optionally carried out during step a) of the process according to the invention. Such a step of removing at least a portion of the inert gases can also be carried out during step b) of the process according to the invention, for example during separation of a mixture of products obtained from step a) or from fractions E2, E2a or E2b. When carrying out the removal of at least part of the inert gases, the removal is preferably carried out during stage a) (stage a6)) of the method according to the invention.

Suitable inert gas separation steps are preferably membrane permeation and adsorption with pressure fluctuations (ΡδΆ). ΡδΆ is preferred.

Optional, at least partially removing some of the oxidized compounds (step a7)).

At least part of the oxygen can be at least partially removed (stage p7a)) by a chemical stage or a physical stage.

A suitable chemical stage is advantageously carried out using a reduced copper layer or a sulfided nickel catalyst, preferably using a sulfided nickel catalyst (step a7-1)).

Another suitable chemical step is preferably a hydrogenation step, which can be catalyzed or not catalyzed, but is preferably catalyzed (step a7a2)).

The hydrogenation step can be carried out using any known hydrogenation catalyst, such as, for example, palladium, platinum, rhodium, ruthenium, iridium, gold, silver catalysts, or mixtures of these elements deposited on a carrier, such as alumina, silica, dioxide silicon / aluminum oxide, coal, calcium carbonate or barium sulfate, but also nickel-based catalysts and cobalt-molybdenum complex catalysts. The hydrogenation step is preferably carried out using a catalyst based on palladium or platinum deposited on alumina or coal, a catalyst based on nickel or a catalyst based on a cobalt-molybdenum complex. In a particularly preferred process, the step is carried out with a nickel based catalyst.

In the hydrogenation stage, predominantly a part of the hydrogen present in LUCS, preferably CBS, is used.

A suitable physical method is preferably carried out by adsorption (stage a7a3)), for example, using ΡδΑ (adsorption with pressure fluctuations), absorption (stage a7-4)) or using a membrane method (stage a7a5)).

Stage a7a2) is specifically preferred.

Stage a7a) is preferably carried out at a temperature between 25 and 100 ° C.

At least part of the nitrogen oxides (stage a7b)) can be at least partially removed by the chemical stage 10 024187 or the physical stage.

A suitable chemical stage is preferably carried out by denox using ammonia or urea, preferably urea (stage a7b1)).

Another suitable chemical step is preferably the hydrogenation step, which can be catalyzed or not catalyzed, preferably it is catalyzed (step a7B2)). Suitable catalysts are preferably palladium or nickel based catalysts, more preferably sulfided nickel catalysts.

The hydrogenation step can be carried out using the same catalysts as the catalysts indicated for the hydrogenation of oxygen, with the same preferences. Hydrogenation catalysts, mainly used in all stages of hydrogenation, are the same. In the hydrogenation stage, a part of the hydrogen present in LUCS, preferably CBS, is preferably used.

Hydrogenation is preferably carried out over denox.

A suitable physical method is preferably carried out by adsorption (stage a7B3)), for example, by means of P8L (adsorption with pressure fluctuations), absorption (stage a7b4)) or by means of a membrane method (stage a7b5)). Suitable adsorbents include activated copper, mineral clay, silica gel and activated alumina.

Stages a7b2) and a7b3) are more specifically preferred.

Stage a7b) is preferably carried out at a temperature between 25 and 100 ° C.

Optional, at least partially removing some of the reactive compounds (step a8)).

The removal of reactive compounds (step a8)) can be carried out in one or several groups of stages, each group containing one or several stages.

The first group of stages (stages a8a)) contains mainly one or several stages of hydrogenation.

Partial hydrogenation of acetylene is preferably carried out in an acetylene converter using a hydrogenation catalyst. After carrying out step a8a), acetylene advantageously becomes at least partially hydrogenated. Suitable types of catalysts include predominantly metals of group VIII, metals of group 1b and metals of group C1b. Preferred are catalysts based on palladium, nickel or gold. More preferred are palladium or nickel based catalysts. Nickel based catalysts are most preferred with particular preference given to sulfided nickel catalysts. Hydrogenation catalysts can be applied or not deposited on a carrier. Preferred are supported catalysts. In other words, it is possible to use catalysts, such as the catalysts indicated for stage a2b).

Organic compounds containing nitrogen present in the hydrogenation feedstock are preferably at least partially removed during the a8a) hydrogenation steps, preferably using a palladium or nickel based catalyst, more preferably a sulfided nickel catalyst.

Organic compounds containing more than one sulfur atom like disulfides can be partially hydrogenated during steps a8a).

The higher acetylenic compounds present in the hydrogenation feedstock, including methylacetylene, propadiene and butadiene, are preferably at least partially hydrogenated during steps a8a), preferably using a palladium or nickel based catalyst, more preferably a sulfided nickel catalyst.

Step a8a) is preferably carried out at a temperature between 25 and 100 ° C.

The second group of stages (stages a8b) contains mainly one or several stages of adsorption.

Adsorption is preferably carried out on chemically specific adsorbents in order, at least partially, to remove other undesirable components.

Organic compounds containing more than one sulfur atom, like disulfides, are advantageously at least partially removed by adsorption in the layer of a suitable substance. Suitable adsorbents include predominantly carbonaceous matter, such as activated carbon and especially activated carbon having a specific surface area between 500 and 2500 m ² / g, molecular sieve 3, 4A or 13X, zeolite, mesoporous adsorbent, including activated alumina, such as mesoporous activated alumina with a BET specific surface between 150 and 800 m ² / g, silica gel, mesoporous silica adsorbent with a BET specific surface between 150 and 800 m ² / g, type A zeolite, type 5A zeolite, X-type zeolite X, zeol IT type fouzite Υ and zeolite MRI. Preferred are activated carbon, molecular sieve 3 or 4A and activated alumina.

During stages a8b), phosphines, methanol and inorganic compounds containing chlorine can also be partially adsorbed.

- 11 024187

Preferably, at least 1, preferably at least 2 adsorbents are used for the a8b adsorption stages. Preferably, at most 6, preferably at most 5, more preferably at most 4 adsorbents are used for the a8b adsorption stages. Most preferably used 3 adsorbent. When performing stage a8b) it is possible to combine or not to combine with stages a3).

The gas flow can be contacted with solid adsorbents in any suitable device. As suitable devices, you can specify moving layers with pneumatic transportation and fixed layers. Fixed layers are preferred.

Adsorbents can be placed in fixed layers or in special layers. They can be placed in one vessel or in separate vessels. The adsorbents are preferably placed in special layers, more preferably in 3 special layers and preferably in separate vessels.

Each stage of adsorption can be carried out in one or several parallel layers. Each adsorption step is preferably carried out in several parallel layers, more preferably in at least 2 separate layers.

Regeneration can be carried out in the device itself or outside the device. Regeneration is preferably carried out in the apparatus itself.

Stage a8b) is preferably carried out at a temperature between 25 and 100 ° C.

The third group of stages (stage a8c)) contains mainly one or several stages of absorption.

The absorption is preferably carried out using a suitable solvent, for example polyethylene glycol dimethyl ether, in order at least partially to remove from among other compounds organic compounds containing more than one sulfur atom per molecule, like disulfides.

Diethanolamine and methanol can advantageously, at least partially, be removed during step a8c).

The various steps mentioned above are not necessarily carried out in the order in which they are indicated. They can be done in any other order.

All or some of the hydrogenation stages a2b), a7a2), a7b2) and a8a) can be advantageously combined. All or some of the adsorption steps a3a), a7a3), a7H3) and a8b) can be advantageously combined. All or some of the absorption steps a2a), a3b), a7a4), a7b4 and a8c) can be advantageously combined.

The preferred order in which the processing steps a2) and a3) are carried out is as follows:

1) stage a3a)

2) stage a3b)

3) stage a2b)

4) Stages a2a)

5) stages a2c) and

6) stages a2b).

When the optional compression stage a1) takes place, the stages a3a), a3b), a2b) and a2c) are preferably included before the last compression stage. When the optional special stage (s) a1bis takes place, it is carried out after stages a2b).

When the optional cooling stage a4) takes place, it is preferably the last stage.

When stage a5a) takes place, it is preferably included in the cooling stage a2c).

When stage a5b occurs, it is predominantly carried out in several stages that are in the cooling stages a2c) and / or stage a4).

When stage a6) takes place, it is preferably included in the cooling stage a2c).

When stage a5a) and stage a6) take place, they are preferably combined.

When stage a7a2 takes place, it is mainly combined with stages a2b).

When stage a7b2 takes place, it is mainly combined with stages a2b).

When stage a7b3 takes place, it is mainly combined with stages a3a).

When the stages a8a), a8b) and a8c) take place, they are preferably combined with the stages a2b), a3a) and a3b), respectively.

A more preferred order in which the processing steps are carried out is as follows:

1) the first stage (s) a1) with the following stages included before the last or only stage of compression,

2) stages a3a) combined with stages a8b) and stage a7b3),

3) stages a3b) combined with stages a8c),

4) stages a2b) combined with stage a7a2), stages a8a) and stage a7b2),

5) Stages a2a)

- 12 024187

6) the last stage of the compression stage A1),

7) stages a2c), combined with part of stage a5b),

8) stage a2b)

9) stage (s) a1bis) and

10) stage a4), combined with part of stage a5b).

The most preferred order in which the processing steps are carried out is as follows:

1) the first stage (s) of stage a1) with the following stages included before the last or only stage of compression,

2) stages a3a combined with stages a8b) and stage a7b3),

3) stages a3b) combined with stages a8c),

4) stages a2b) combined with stage a7a2), stages a8a) and stage a7b2),

5) Stages a2a)

6) the last stage of the compression stage A1),

7) stages a2c), combined with stage a5a), stage a5b) and part of stage a5b),

8) stage a2b)

9) stage (s) a1bis) and

10) stage a4), combined with part of stage a5b).

In the method according to the invention, the mixture of products containing ethylene and other components obtained from step a) mainly contains hydrogen, methane, ethane, ethylene, propane, hydrocarbons containing 4, 5 or 6 carbon atoms, and higher molecular weight hydrocarbons with C6 +, inert gases, oxidized compounds, reactive compounds and a significantly reduced amount of corrosive compounds, and compounds that poison the catalyst.

The concentration of inert gases is optionally, at least partially, reduced compared with their concentration at the inlet.

The content of some of the reactive compounds is optionally, at least partially, reduced compared with their content at the inlet. Preferably it is at least partially reduced compared with their content at the inlet.

The concentration of combustible gases (other than ethylene) is not necessarily, at least partially, reduced compared to their concentration at the inlet. The concentration of some of the combustible gases having a boiling point under normal conditions is higher than the boiling point of ethylene under normal conditions, preferably at least partially reduced compared to their concentration at the inlet. The concentration of some of the combustible gases that have a boiling point under normal conditions is lower than the boiling point of ethylene under normal conditions, preferably at least partially reduced compared to their concentration at the inlet. More preferably, the concentration of some of the combustible gases having a boiling point under normal conditions is lower than the boiling point of ethylene under normal conditions, and the concentration of some of the combustible gases having a boiling point under normal conditions is higher than the boiling point of ethylene under normal conditions, at least partially reduced compared with their concentration at the inlet.

The compositions, which are listed below for a mixture of products containing ethylene and other components, obtained from stage a), calculated on the basis of dry gas (water is not included).

The mixture of products containing ethylene and other components, obtained from stage a), mainly contains at least 10, preferably at least 15, more preferably at least 20% by volume of ethylene. It advantageously contains at most 60, preferably at most 55, more preferably at most 50% by volume of ethylene.

The mixture of products containing ethylene and other components, obtained from stage a), is mainly characterized by a lower calorific value, preferably at least 30, preferably at least 33, more preferably at least 35 and most preferably at least 37 MJ / kg dry gas. The mixture of products containing ethylene and other components, obtained from stage a), is mainly characterized by a lower calorific value, preferably at most 75, preferably at most 70, more preferably at most 65 and most preferably at most 60 MJ / kg dry gas.

The partial pressure of water contained in a mixture of products containing ethylene and other components and obtained from stage a) is preferably lower than 7332.271 Pa (55 mm Hg), preferably lower than 3333.15 Pa (25 mm Hg .), more preferably lower than 1999.83 Pa (15 mm Hg) and most preferably lower than 1333.22 Pa (10 mm Hg).

The mixture of products containing ethylene and other components, obtained from stage a), contains each of the following components, i.e. carbon dioxide, hydrogen sulfide, carbonyl sulfide, organic compounds containing one sulfur atom per molecule, like mercaptans and sulfides, sulfur oxides, ammonia, nitrides, nitriles, hydrogen chloride, hydrogen cyanide, arsenic (like arsines), vanadium, bromine, fluorine, silicon, aluminum and metal carbonyls in an amount that is predominantly

- 13,024,187 is at most 5%, preferably at most 2% and more preferably at most 1% of the amount of the same component in the LUX, preferably CBS, directed to stage a) and / or formed during stage a).

After stage a) above, a mixture of products containing ethylene and other components is subjected to stage b), which is first the separation stage of §1, which consists in separating said products containing ethylene and other components, into a fraction containing compounds that are higher than ethylene, and part of ethylene, and called the fraction P1, and the fraction P2.

Before its separation, a mixture of products containing ethylene and other components can be subjected to heat conditioning steps.

The term “heat conditioning stage” is intended to mean using a sequence of heat exchangers to control the temperature of the mixture for separation requirements and / or optimize the use of energy, preferably to control the temperature of the mixture for separation requirements and optimize the use of energy.

When the stage of thermal conditioning is cooling, cooling is mainly a gradual cooling of the product mixture in a series of exchangers, first cooled with untreated water, then with ice-cooled water and then with increasing cooling liquids, plus cross exchangers utilizing significant heat from the streams obtained, not necessarily latent heat, when it is available. The condensates formed during the cooling stage are preferably physically separated from the gas stream and sent to a suitable place in the subsequent processing. The conditioning of the heat included in step §1 is preferably cooling, and the separated condensate is preferably sent to a suitable place in step §2.

The first stage of the separation of §1 consists predominantly in the fractionation of a mixture of products containing ethylene and other components into the two different fractions indicated above.

The term fractionation is intended to mean for the purpose of the present invention that any part of a potentially multi-step process that can be considered has one function. The stage of fractionation can be carried out in one or several interconnected devices.

Examples of fractionation include distillation, extractive distillation, liquid extraction with liquid, diffusion evaporation, gas penetration, adsorption, pressure swing adsorption (PgА), temperature swing adsorption (ТgА), absorption, chromatography, reverse osmosis and molecular filtration. Distillation is preferred.

Therefore, stage §1 preferably consists in fractionating a mixture of products containing ethylene and other components, inside a distillation column (called column C1) into two different fractions, namely the P1 fraction, which mainly leaves the rectification section of C1 C1, and the P2 fraction, which predominantly out of the stripping section of the column C1.

The term distillation column according to the present invention means that the column contains any number of interconnected towers. A tower means one shell in which countercurrent contacting of liquid and gas is performed.

Column C1 mainly does not contain more than two interconnected towers. Column C1 preferably consists of a single tower.

Column C1 can be selected from plate-type distillation columns, distillation columns with an arbitrary packing, distillation columns with a structured packing, and distillation columns connecting two or more of the above-mentioned internal parts.

Column C1 is preferably provided with associated additional elements, such as, for example, at least a heating source and a cooling source. The heat source is preferably a reboiler. The source of cooling can be a source of direct or indirect cooling. An example of indirect cooling is a partial irrigation condenser. An example of direct cooling is the adiabatic flash evaporation of a liquid formed by a partial condenser of hot cooling. Direct cooling by adiabatic flash evaporation of the liquid formed by the partial condenser (hot irrigation) is preferred. The gas subjected to partial condensation in the partial reflux condenser can be obtained from column C1 or from a mixture of products sent to column C1 after a possible thermal conditioning step, preferably from column C1. The stream obtained from the column can be withdrawn from the stripping section or from the rectification section, preferably from the stripping section of the column C1. It can be sampled at any place in the stripping section, preferably in the upper third of the stripping section, more preferably at the location directly below the place into which the mixture of products is fed.

This mixture of products can be introduced into column C1 as a single fraction or as several subfractions. It is preferably administered in the form of several subfractions.

The above step §1 is preferably carried out at an absolute pressure of at least 15x10 ⁵ Pa (5 bar), preferably at least 10x10 ⁵ Pa (10 bar) and particularly preferably

- 14 024187 at least 12x10 ⁵ Pa (12 bar). Stage 81 is preferably carried out at an absolute pressure of at most 40x10 ⁵ Pa (40 bar), preferably at most at 38x10 ⁵ Pa (38 bar) and particularly preferably at most at 36x10 ⁵ Pa (36 bar).

The temperature at which step 81 is carried out is preferably at least -40, preferably at least -35, and particularly preferably at least -30 ° C at the bottom of the stripping section of the column C1. It is preferably at most 80, preferably at most 60, and particularly preferably at most 40 ° C at the bottom of the stripping section of the column C1.

The temperature at which stage 81 is carried out is preferably at least -110, preferably at least -105, and particularly preferably at least -100 ° C at the upper part of the rectification section of the column C1. It is preferably at most 0, preferably at most -15, and particularly preferably at most -25 ° C at the upper part of the rectification section of the column C1.

After the aforementioned stage b) fraction P1 is sent to an ethylene separation unit in which it is divided into a fraction enriched in ethylene, called the E1 fraction, and a fraction enriched in compounds that are lighter than ethylene and called the light fraction (stage c )).

The separation in the ethylene separation unit consists mainly in the fractionation of the P1 fraction into two different fractions indicated above. Reference is made to the definition of the term fractionation, as well as to the examples of fractionation indicated above for stage b).

According to the first embodiment of step c), the P1 fraction is preferably subjected to an absorption stage followed by a desorption stage, in which said P1 fraction is preferably contacted with a washing agent containing a solvent for separation into the E1 fraction and into the light fraction.

It is assumed that the expression washing agent containing a solvent, or more simply washing agent, means a composition in which the solvent is present in a liquid state.

Therefore, the washing agent that can be used according to the present invention advantageously contains a solvent in a liquid state. The presence in the specified washing agent of all other compounds is not excluded from the scope of the invention. However, it is preferable that the washing agent contains at least 50% by volume of the solvent, more specifically at least 65% by volume and most preferably at least 70% by volume.

The first group of solvents that can be used are solvents, preferably characterized by a melting point which is equal to or lower than -110 ° C, preferably equal to or lower than -105 ° C, more preferably equal to or less than -100 ° C.

The second group of solvents that can be used are solvents characterized by a melting point higher than the melting point of the solvents of the first group. However, in this latter case, a suitable thermal conditioning step of the P1 fraction is advantageously used. Thermal conditioning is preferably a heat conditioning step, indicated in step b).

As solvents according to the first group, for example, saturated hydrocarbons, unsaturated hydrocarbons and mineral oils can be mentioned.

Saturated or unsaturated hydrocarbons can be used as a single hydrocarbon or as a mixture of hydrocarbons. Examples of saturated and unsaturated hydrocarbons are propane / butane (LPO) mixtures, benzene, heavy fractions obtained by the method according to the invention, cyclopentane and its derivatives, cyclopentene and its derivatives, in particular methylcyclopentene and ethylcyclopentene, cyclohexane and its derivatives, in particular methylcyclohexane and ethylcyclohexane , cyclohexene and its derivatives and C ₈ -C ₉ isoparaffins. Methylcyclohexane, ethylcyclohexane and C ₈ -C ₉ isoparaffins are preferred. Methylcyclohexane and ethylcyclohexane are particularly preferred.

As solvents according to the second group, for example, chlorinated solvents (like OEC), alcohols, glycols, polyols, ethers, mixtures of glycol (s) and ether (s) can be mentioned.

Solvents of the first group are preferred in comparison with solvents of the second group.

The washing agent used for the absorption step may consist of a fresh washing agent or, in whole or in part, a washing agent recovered during the desorption step, described below, after optional treatment, optionally with the addition of a fresh washing agent.

The relationship between the respective quantities of the washing agent and the P1 fraction is not critical and can change to a large value. In practice, it is limited only by the cost of regenerating the washing agent. In general, the quantity to be passed

- 10 024187 washing agent is at least 0.1, preferably at least 0.2 and particularly preferably at least 0.25 tons per ton of P1 fraction. In general, the throughput of the washing agent is at most 100, preferably at most 50 and particularly preferably at most 25 tons per tonne of fraction P1.

The absorption step is advantageously carried out using an absorber, such as, for example, an absorber in the form of a rising film or falling film, or an absorption column selected from the plate columns, arbitrary filling columns, structured filling columns, columns combining one or more of the above fillings and irrigated columns. The absorption step is preferably carried out with the aid of absorption columns and particularly preferably with the aid of plate absorber columns.

The absorption column may or may not be equipped with an attached heat exchanger. When using solvents of the first group, the absorption column is preferably not provided with an attached heat exchanger. When solvents of the second group are used, the absorption column is preferably provided with an attached heat exchanger.

When solvents of the first group are used, the absorption step mentioned above is preferably carried out at an absolute pressure of preferably at least 15x10 ⁵ Pa (15 bar), preferably at least 20x10 ⁵ Pa (20 bar) and particularly preferably at least 25x10 ⁵ Pa (25 bar ). The absorption step is carried out at a pressure of preferably at most 40x10 ⁵ Pa (40 bar), preferably at most 35x10 ⁵ Pa (35 bar) and particularly preferably at most 30x10 ⁵ Pa (30 bar).

When solvents of the first group are used, the temperature at which the absorption step is carried out is preferably at least -110, preferably at least -105 and particularly preferably at least -100 ° C in the upper part of the absorber or absorption column. The temperature of the upper part of the absorber or absorption column is preferably at most -50, preferably at most -60, and particularly preferably at most -65 ° C. In addition, the temperature at which the absorption step is carried out is preferably 2, preferably 5 ° C higher than the melting point of the solvent.

When using solvents of the first group, the temperature of the lower part of the absorber or absorption column is at least -110, preferably at least -105 and particularly preferably at least -100 ° C. It is preferably at most -50, preferably at most -60, and particularly preferably -65 ° C.

When solvents of the second group are used, the absorption step mentioned above is carried out preferably at an absolute pressure of preferably at least 15x10 ⁵ Pa (15 bar), preferably at least 20x10 ⁵ Pa (20 bar) and particularly preferably at least 25x10 ⁵ Pa (25 bar ). The absorption step is carried out at an absolute pressure of preferably at most 40x10 ⁵ Pa (40 bar), preferably at most 35x10 ⁵ Pa (35 bar) and particularly preferably at most 30x10 ⁵ Pa (30 bar).

When solvents of the second group are used, the temperature at which the absorption step is carried out is preferably at least -10, preferably at least 0, and particularly preferably at least 10 ° C in the upper part of the absorber or absorption column. The temperature of the upper part of the absorber or absorption column is preferably at most 60, preferably at most 50 and particularly preferably at most 40 ° C.

When using solvents of the second group, the temperature of the lower part of the absorber or the absorption column is at least 0, preferably at least 10 and particularly preferably at least 20 ° C. It is preferably at most 70, preferably at most 60, and particularly preferably at most 50 ° C.

The effluent from the absorption stage, which is the P1 fraction of the purified compounds, which are lighter than ethylene and rich in washing agent, is preferably subjected to a desorption stage.

The washing agent recovered after the desorption step is preferably fully or partially directed to the absorption step after the above optional treatment with the optional addition of a fresh washing agent.

The desorption step is preferably carried out using a desorber, such as, for example, a desorber in the form of a rising film or a falling film, a reboiler or desorption column selected from dish-shaped columns, columns with arbitrary filling, columns with structured filling, columns combining one or more of the above. fillings, and irrigated columns. The desorption step is preferably carried out using desorption columns, and particularly preferably using a plate desorption column.

The desorption column is preferably provided with connected additional devices, such as, for example, at least a condenser or one refrigeration unit, which is located inside or outside the column, and at least one reboiler.

The desorption pressure is advantageously chosen such that the ethylene content in the regenerated solvent is less than 4 or equal to 4, preferably less than 3.2 or equal to 3.2 wt.%.

When solvents of the first group are used, the above-mentioned desorption stage is preferably carried out at an absolute pressure, preferably at least 1x10 ⁵ Pa (1 bar), preferably at least 2x10 ⁵ Pa (2 bar) and particularly preferably at least 3x10 ⁵ Pa (3 bar). The desorption step is carried out at an absolute pressure of preferably at most 25x10 ⁵ Pa (25 bar), preferably at most 20x10 ⁵ Pa (20 bar) and particularly preferably at most 18x10 ⁵ Pa (18 bar).

When solvents of the first group are used, the temperature at which the desorption step is carried out is preferably at least -10, preferably at least 0, and particularly preferably at least 10 ° C in the upper part of the stripper or desorption column. The temperature of the top of the stripper or stripper is preferably at most 60, preferably at most 50 and particularly preferably at most 45 ° C.

When solvents of the first group are used, the temperature of the bottom of the stripper or desorption column is at least 20, preferably at least 25, and particularly preferably at least 30 ° C. It is preferably at most 200, preferably at most 160 and particularly preferably at most 150 ° C.

When using solvents of the second group, the above desorption stage is carried out at an absolute pressure of preferably at least 1x10 ⁵ Pa (1 bar), preferably at least 2x10 ⁵ Pa (2 bar) and particularly preferably at least 3x105 Pa (3 bar) . The desorption step is carried out at a pressure of preferably at most 20x10 ⁵ Pa (20 bar), preferably at most 15x10 ⁵ Pa (15 bar) and particularly preferably at most 10x10 ⁵ Pa (10 bar).

When solvents of the second group are used, the temperature at which the desorption step is carried out is preferably at least -10, preferably at least 0, and particularly preferably at least 10 ° C in the upper part of the stripper or desorption column. The temperature of the top of the stripper or stripper is preferably at most 60, preferably at most 50 and particularly preferably at most 45 ° C.

When solvents of the second group are used, the temperature of the bottom of the stripper or desorption column is at least 60, preferably at least 80 and particularly preferably at least 100 ° C. It is preferably at most 200, preferably at most 160 and particularly preferably at most 150 ° C.

The regenerated solvent is advantageously at least partially used again at absorption after the heat conditioning step, preferably including cooling in a cross heat exchanger with a solvent leaving the absorption column.

The most specific preference is given to the case in which the absorption stage is carried out in an absorption column and the desorption stage is carried out in a desorption column.

In the specific case where the method according to the invention is intended to produce an EfE, it may be interesting to use a washing agent consisting of an EfE. In such a case, the washing agent used for the absorption step may consist of a crude EfE exiting the chlorination unit, a crude EfE exiting the oxychlorination unit, or a mixture of two such EfEs that has not been purified. It may also consist of the specified EfE that has been pre-cleaned, or the entire amount or part of the washing agent recovered during the desorption stage, after optional treatment, optionally with the addition of a fresh washing agent. Desorption can also be carried out by direct injection of vapor in order to collect the EfE.

A significant advantage of the case when EfE is a washing agent is the fact that the presence of this EfE does not create any difficulty at all, because it is a compound mainly formed during oxychlorination or chlorination.

According to the second embodiment of step c), the fraction P1 is preferably subjected to an adsorption stage followed by a desorption stage in order to separate it into an E1 fraction and a light fraction.

The adsorption stage preferably comprises passing the P1 fraction through the adsorption layer loaded with the adsorbent. The absorbent bed may be a fluid bed or a fixed bed. Any known adsorbent known in the art may be used. Examples of such adsorbents are adsorbents based on silver compounds or copper compounds. These silver or copper compounds are usually deposited on a carrier having a sufficiently high surface area. Examples of carriers are activated carbon, charcoal, activated alumina and zeolite. Adsorbents are usually solids in the form of tablets or pellets.

- 17 024187

The adsorption step is preferably carried out at an absolute pressure of at least 15x10 ⁵ Pa (15 bar), at least 20x10 ⁵ Pa (20 bar) and particularly preferably at least 25x10 ⁵ Pa (25 bar). The adsorption step is preferably carried out at a pressure of at most 40x10 ⁵ Pa (40 Pa), preferably at most 35x10 ⁵ Pa (36 Pa) and particularly preferably at most 30x10 ⁵ Pa (30 Pa).

The temperature at which the adsorption step is carried out is preferably at least -10, preferably at least 0, more preferably at least 10 and most preferably at least 20 ° C. It is preferably at most 70, preferably at most 60, more preferably at most 50 and most preferably at most 40 ° C.

The desorption step can be easily carried out by reducing the pressure, increasing the temperature or lowering the pressure and increasing the temperature of the adsorber layer, resulting in a regenerated adsorbent.

The desorption step is preferably carried out at an absolute pressure of at least 1x 10 ⁵ Pa (1 bar), preferably at least 2x 10 ⁵ Pa (2 bar) and particularly preferably at least 3x10 ⁵ Pa (3 bar). The desorption step is preferably carried out at an absolute pressure of at most 20x10 ⁵ Pa (20 bar), preferably at most 15x10 ⁵ Pa (15 bar) and particularly preferably at most 10x10 ⁵ Pa (10 bar).

The temperature at which the desorption step is carried out is preferably at least -10, preferably at least 10, more preferably at least 20 and most preferably at least 60 ° C. It is advantageously at most 200, preferably at most 160, more preferably at most 100 and most preferably at most 60 ° C.

When a fluidized layer is used, the adsorbent is advantageously continuously circulating from the adsorption layer to the desorption layer.

When a fixed bed is used, a circular process is advantageously carried out, preferably when several layers are applied in parallel, more preferably in at least one adsorption phase and in at least one desorption phase.

The first embodiment of step c) is preferred over the second embodiment.

The light fraction is enriched with compounds that are lighter than ethylene. These compounds are typically hydrogen, oxygen, nitrogen, helium, argon, carbon monoxide, and methane.

The light fraction preferably contains at least 75%, preferably at least 80% and more preferably at least 85% methane, which is contained in the P1 fraction subjected to stage c).

The light fraction preferably contains at least 90%, preferably at least 95% and more preferably at least 97% of nitrogen, oxygen, hydrogen, carbon monoxide, argon and helium, which are contained in fraction P1, subjected to stage c).

The light fraction contains preferably less than 2%, preferably less than 1.5%, and more preferably less than 1% by volume of ethylene.

After separation, the light fraction can be burned as fuel or valorized chemically, preferably valorized chemically.

The light fraction can be subjected to a chemical reaction, such as partial oxidation, or steam reforming in order to preferentially convert the hydrocarbons contained in it into hydrogen, before chemical valorization. When the light fraction is especially enriched in hydrogen, it can be used for any hydrogenation reaction, such as, for example, for hydrogenation of the working solution when producing hydrogen peroxide by self-oxidation or for direct synthesis of hydrogen peroxide.

Alternatively, the light fraction can be valorized in the synthesis gas after the hydrocarbons contained therein are converted by steam reforming or partial oxidation, followed by a change in the ratio of carbon monoxide and hydrogen in water gas in order to obtain derivatives, such as methanol, in a Fisher-Tropsch unit .

Alternatively, synthetic natural gas can be obtained.

The energy of the light fraction can also be recovered by turboexpansion.

Fraction E1, subjected to stage c), contains predominantly at least 50%, preferably at least 60% and more preferably at least bb% ethylene.

After step c) above, the E1 fraction is recycled to step a) or sent to obtain at least one ethylene derivative (step b)).

In the case where the E1 fraction is recycled to stage a), the E1 fraction can be recycled to stage a) at any place in the stage. The E1 fraction can be recycled at the entrance to stage a) and / or to one or more than one of the stages from a1) to a8).

- 18 024187

The E1 fraction is advantageously recycled to the inlet of stage a), to stage a1) and / or stage a4). The E1 fraction is preferably recycled to stage a1) and / or stage a4).

The E1 fraction can be recycled with or without adaptation of its pressure.

When it is necessary to adapt its pressure, the E1 fraction is mainly subjected to compression, possibly in combination with cooling downstream or upstream, either in the ethylene recovery unit itself, or after being removed from this plant, before recirculating it to the inlet to stage a) and / or one or more than one of the stages from a1) to a8). Compression can be performed by any known method, such as a mechanical compressor, a gas ejector, a liquid ejector. The compression is preferably carried out with a mechanical compressor.

When the E1 fraction is recycled without adapting its pressure, the E1 fraction is preferably recycled to the inlet to stage a) and / or one or more of one of the stages from a1) to a8), where the pressure is suitable, in other words, where the pressure is less than pressure fraction E1.

The E1 fraction can be recycled as one part or as several parts. Fraction 1 is preferably recycled as one portion.

More preferably, the E1 fraction is recycled to step a1) or to step a4).

When the E1 fraction is recycled to stage a1), it is mainly recycled without adapting its pressure.

The E1 fraction is then preferably recirculated to either a single stage of a multi-stage gas compressor when only one compressor is used, or to a compressor from a number of compressors when several compressors are used that are at a higher pressure but lower than the pressure of the E1 fraction.

When the E1 fraction is recycled to step a4), it is preferably recycled after its pressure has been adapted, preferably by compressing it.

Most preferably, the E1 fraction is recycled to step a1) without adapting its pressure, as described above.

Alternatively, the E1 fraction can be directed to the preparation of at least one ethylene derivative. The E1 fraction can be sent as such for such preparation, or it can be mixed with the E2 fraction or one of the E2a and E2b fractions obtained in step c) before it is sent for such preparation. When the E1 fraction is directed to obtain at least one ethylene derivative, it is preferably sent for the chlorination of ethylene, thus obtaining 1,2-dichloroethane.

The energy of the E1 fraction can be recovered by turboexpansion.

One part of the E1 fraction can be recycled to stage a), while the other part is sent to obtain at least one ethylene derivative.

The E1 fraction is preferably recycled to step a). The UX containing the fraction E1 recycled from stage b) is preferably therefore subjected to a number of processing steps indicated for stage a).

According to stage e), the P2 fraction is subjected to the second stage of the separation of §2, which consists of separating the P2 fraction into one fraction enriched in ethylene and called the E2 fraction, or into two fractions enriched with ethylene and called the E2a and E2b fractions, and into the fraction enriched ethane and a hydrocarbon containing at least 3 carbon atoms, and called the heavy fraction.

Before its separation, the P2 fraction can be subjected to heat conditioning stages.

It is assumed that the term heat conditioning stage means using a series of heat exchangers to regulate the temperature of the P2 fraction to achieve the necessary separation conditions and / or optimize the use of energy, preferably to regulate the temperature of the P2 fraction to achieve the necessary separation conditions and optimize the use of energy. The P2 fraction is not necessarily adiabatically instantaneously evaporated at the pressure of the location of the vapor supply in §2 and the condensates obtained during the adiabatic flash evaporation are physically separated from the gas flow and directed to a suitable location in §2.

Stage §2 of the second division mainly consists in the fractionation of the P2 fraction into the various fractions indicated above.

The term fractionation is intended to mean for the purpose of the present invention any part of a potentially multi-step process that can be considered as having one function. The fractionation stage can be carried out in one or more interconnected devices.

Examples of fractionation include distillation, extractive distillation, liquid extraction with liquid, diffusion evaporation, gas permeation, adsorption, pressure swing adsorption (PgА), temperature swing adsorption (TgА), absorption, chromatography, reverse osmosis and molecular filtration. Distillation is preferred.

Therefore, step §2 preferably consists in fractionating the P2 fraction predominantly within at least one distillation column, preferably one or two distillation columns, into the above-mentioned different fractions.

The term distillation column according to the present invention means that the column contains 19,024,187 holds any number of interconnected towers. The term tower means one shell in which countercurrent contacting of liquid and gas is carried out.

Each distillation column preferably contains no more than two interconnected towers. More preferably, each distillation column consists of a single tower.

Each distillation column can be selected from plate-type distillation columns, distillation columns with an arbitrary packing, distillation columns with a structured packing and distillation columns combining two or more of the above internal parts.

According to the first embodiment of step e), the P2 fraction is preferably subjected to the second separation stage §2, which consists in the separation of the P2 fraction into the E2 fraction and the heavy fraction.

According to the first embodiment of step e), the second separation step §2 preferably consists in fractionating the P2 fraction within one distillation column (called the C2 column) into two different fractions, namely the E2 fraction, which mainly comes out of the rectifying section of the C2 column, and the heavy fraction, which preferably leaves the stripping section of column C2.

The column C2 is advantageously provided with connected auxiliary means, such as, for example, at least a heating source and a cooling source. The heat source is preferably a reboiler. The source of cooling can be a source of direct or indirect cooling. An example of indirect cooling is cooling with a partial condenser. An example of direct cooling is the adiabatic flash evaporation of a liquid formed by a partial condenser.

Direct cooling by adiabatic flash evaporation of the liquid formed by the partial condenser is preferred. Optimization of energy saving requirements can be achieved by any means known in the art, such as cross-heat exchange with suitable fluids, integration of column heat with steam recompression, combining the recompression cycle with cooling and adiabatic flash evaporation.

The P2 fraction can be introduced into the C2 column as a single fraction or as several subfractions. It is preferably administered as a single fraction.

According to the first embodiment of step e), step §2 is preferably carried out at an absolute pressure of at least 5x10 ⁵ Pa (5 bar), preferably at least 10x10 ⁵ Pa (10 bar) and particularly preferably at least 12x10 ⁵ Pa (12 bar) . Stage §2 is preferably carried out at an absolute pressure of at most 40x10 ⁵ Pa (40 bar), preferably at most 38x10 ⁵ Pa (38 bar) and particularly preferably at most 36x10 ⁵ Pa (36 bar).

According to the first embodiment of step e), the temperature at which step §2 is carried out is preferably at least -50, preferably at least -40, and particularly preferably at least -30 ° C at the bottom of the stripping section of the column C2. It is preferably at most 80, preferably at most 75 ° C at the bottom of the stripping section of the column C2.

According to the first embodiment of step e), the temperature at which step §2 is carried out is preferably at least -80, preferably at least -70, and particularly preferably at least -65 ° C at the top of the rectifying section of the column C2. It is preferably at most 5, preferably at most 0, and particularly preferably at most -3 ° C at the top of the rectifying section of column C2.

According to the second variant of the first embodiment of stage e), the second stage of separation §2 mainly consists in separating the P2 fraction in two different stages of separation, the first stage of separation, called stage §2 ', and the second stage of separation, called stage §2, in order to obtain fraction E2 and heavy fraction.

According to this second variant of the first embodiment of step e), the P2 fraction is subjected to the first separation step §2 ', which consists in separating the P2 fraction into the first fraction enriched in ethylene and called the E2' fraction, and into the fraction enriched in ethane and hydrocarbon containing at least 3 carbon atoms, and containing part of ethylene and named fraction P2 '; and the second stage of separation of §2, which consists in the separation of the P2 'fraction into the second fraction enriched in ethylene and called the E2 fraction, and into the heavy fraction.

The fraction E2 ′ and the fraction E2 are then preferably mixed. They can be mixed immediately after they are obtained, after they are circulated in a device for energy regeneration and / or after they are included in the cooling cycle used in steps b) to e). They are preferably mixed after being circulated in a device for energy recovery and / or after they are included in the cooling cycle used in stages b) to e). More preferably, they are mixed after being circulated in a device for energy recovery and after being included in the cooling cycle used in steps b) to f).

Stage §2 'preferably consists in the fractionation of the P2 fraction in the first distillation

- 20 024187 column (called column C2 ') into two different fractions, namely the fraction E2', which mainly leaves the rectification section of the column C2 ', and fraction P2', which mainly leaves the stripping section of the column C2 '.

Stage §2 preferably consists in fractionation of the P2 'fraction in the second distillation column (called the C2 column) into two different fractions, namely, the E2 fraction, which mainly leaves the rectification section of the C2 column, and the heavy fraction, which mainly leaves their rectification section columns C2.

The column C2 'is preferably provided with connected auxiliary elements, such as, for example, at least one heating source and a cooling source. The heat source is preferably a reboiler. The source of cooling can be a source of direct or indirect cooling. An example of indirect cooling is cooling with a partial condenser. An example of direct cooling is the adiabatic flash evaporation of a liquid formed by a partial condenser. Direct cooling by adiabatic flash evaporation of the liquid formed by the partial condenser is preferred.

Optimization of energy saving requirements can be achieved by any means known in the art, such as cross-heat exchange with suitable liquids; heat integration in one of the cooling cycles used in stages b), c) and e) (preferably in the cooling cycle used in stages b), c) and e)); the integration of the heat of the C2 'column with vapor recompression or a recompression cycle combined with cooling and adiabatic flash evaporation; integrating the heat of column C2 'and column C2 with a suitable choice of column pressure in such a way that the condenser of one of the columns is a reboiler of another column, preferably a column C2 operating at a higher pressure than the column C2', so that the condenser of the column C2 'could be a reboiler of the column C2 '. More preferably, energy saving requirements are optimized by integrating heat in one of the cooling cycles used in stages b), c) and e) (preferably in the cooling cycle used in stages b), c) and e)).

The P2 fraction can be introduced into the C2 'column during the §2' stage as a single fraction or as several subfractions. It is preferable to administer as a single fraction.

According to the second variant of the first embodiment of step e), step §2 'is preferably carried out at an absolute pressure of at least 5x10 ⁵ Pa (5 bar), preferably at least 10x10 ⁵ Pa (10 bar) and particularly preferably at least 12x10 ⁵ Pa (12 bar). Stage §2 'is preferably carried out at a pressure of at most 40x10 ⁵ Pa (40 bar), preferably at most 38x10 ⁵ Pa (38 bar) and particularly preferably at most 36x10 ⁵ Pa (36 bar).

According to the second embodiment of the first embodiment of step e), the temperature at which step §2 'is carried out is preferably at least -50, preferably at least -45, and particularly preferably at least -43 ° C at the bottom of the stripping section of the column C2 '. It is preferably at most 30, preferably at most 20, and particularly preferably at most 10 ° C at the bottom of the stripping section of the column C2 '.

According to the second variant of the first embodiment of step e), the temperature at which step §2 'is carried out is advantageously at least -70, preferably at least -65, and particularly preferably at least -63 ° C at the upper part of the rectification section of column C2 '. It is preferably at most 0, preferably at most -15, and particularly preferably at most -25 ° C at the top of the rectification section of the column C2 '.

Before being introduced into column C2, fraction P2 'can be subjected to heat conditioning stages, as indicated for stage 1, and pressure conditioning stages by transferring the liquid obtained from the bottom of the stripping section of column C2' into column C2.

The column C2 is advantageously provided with connected auxiliary elements, such as, for example, at least one heating source and a cooling source with the same characteristics as those indicated for the column C2 ′ above in context.

The P2 'fraction can be introduced into the C2 column during the stage of §2 as a single fraction or several subfractions. It is preferably administered as a single fraction.

According to the second embodiment of the first embodiment of step e), step §2 is advantageously carried out at an absolute pressure of at least 5x10 ⁵ Pa (5 bar), preferably at least 10x10 ⁵ Pa (10 bar) and particularly preferably at least 12x10 ⁵ Pa ( 12 bar) Stage §2 is preferably carried out at a pressure of at most 40x10 ⁵ Pa (40 bar), preferably at most 38x10 ⁵ Pa (38 bar) and particularly preferably at most 36x10 ⁵ Pa (36 bar).

According to the first variant of the second variant of the first embodiment of stage e), the E2 ′ and E2 fractions are mixed immediately after they are received. In such a variant, the stage §2 is predominantly carried out at a pressure equal to or different from the pressure at which §2 'is carried out. Stage §2 is preferably carried out at a pressure other than the pressure at which §2 'is carried out. Stage §2 mainly carried out at a pressure that is slightly lower than the pressure

- 21 024187 at which stage 82 'is carried out.

According to the second sub-variant of the second variant of the first embodiment of stage e), the fractions E2 ′ and E2 are mixed after being circulated into a device for energy regeneration and / or after being integrated into the cooling cycle, used in stages b) to e). In such a variant, stage 82 is preferably carried out at a pressure equal to or different from the pressure at which the 82 'is conducted. Stage 82 is preferably carried out at a pressure other than the pressure at which the 82 'is conducted. Stage 82 is preferably carried out at a pressure higher than the pressure at which step 82 ′ is carried out. Step 82 is carried out at a pressure which is preferably at least 2x10 ⁵ Pa (2 bar), more preferably at least 4x10 ⁵ Pa (4 bar), most preferably at least 5 × 10 ⁵ Pa (5 bar) above, than the pressure at which conduct stage 82 '.

Stage 82 is carried out at a pressure that is preferably at most 33x10 ⁵ Pa (33 bar), preferably at most 30x10 ⁵ Pa (30 bar), most preferably at most 20x 10 ⁵ Pa (20 bar) more than the pressure, at which conduct stage 82 '.

According to the second embodiment of the first embodiment of step e), the temperature at which step 82 is carried out is preferably at least -50, preferably at least -40, and particularly preferably at least -30 ° C at the bottom of the stripping section of the column C2. It is preferably at most 80, preferably at most 75, and particularly preferably at most 72 ° C at the bottom of the stripping section of the column C2.

According to the second embodiment of the first embodiment of step e), the temperature at which step 82 is carried out is advantageously at least -70, preferably at least -65, and particularly preferably at least -63 ° C at the upper part of the rectification section of the column C2. The temperature is preferably at most 0, preferably at most -15, and particularly preferably at most -25 ° C at the top of the rectification section of column C2.

According to the second embodiment of step e), the P2 fraction is preferably subjected to the second separation stage 82, which consists of separating the P2 fraction into fractions Е2а and Е2Ь and into the heavy fraction.

According to this second embodiment of stage e), the second separation stage 82 advantageously consists in separating the P2 fraction in two different separation stages, the first separation stage, called 82 '' ', and the second separation stage, called stage 82, in order to obtain the Е2a fraction and Е2Ь and heavy fraction.

According to this second embodiment of step e), the P2 fraction is subjected to the 82 ″ ′ first separation stage, which consists of dividing the P2 fraction into the Е2a fraction and into the fraction enriched in ethane and hydrocarbon containing at least 3 carbon atoms and containing part of ethylene and named P2 'fraction; and a second separation stage 82, which consists in separating the P2 ″ ’fraction into the E2B fraction and into the heavy fraction.

Stage 82 ″ ″ preferably consists of fractionating the P2 fraction in the first distillation column (called the C2 ″ column) into two different fractions, namely the E2a fraction, which mainly leaves the rectification section of the C2 ″ ’column, and the P2 ″ fraction ', which predominantly leaves the stripping section of the column C2 ″ ″.

Stage 82 preferably consists in fractionating the P2 ″ ’fraction on the second distillation column (called the C2 column) into two different fractions, namely the E2b fraction, which mainly leaves the rectification section of the C2 column, and the heavy fraction, which mainly leaves the section rectification of column C2.

The column C2 ″ ″ is preferably provided with connected auxiliary elements, such as, for example, at least a heating source and a cooling source. The heat source is preferably a reboiler. The source of cooling can be a source of direct or indirect cooling. An example of indirect cooling is cooling with a partial condenser. An example of direct cooling is the adiabatic flash evaporation of a liquid formed by a partial condenser.

Direct cooling by adiabatic flash evaporation of the liquid formed by the partial condenser is preferred.

Optimization of energy saving requirements can be achieved by any means known in the art, such as cross-heat exchange with suitable liquids; integration of column heat with vapor recompression or a recompression cycle in combination with cooling and adiabatic flash evaporation; the integration of substances from one of the columns C2 ″ ″ and C2 (preferably C2 ″ ″) in the cooling cycle used for stage b), c) and e); the integration of heat from one of the columns and the integration of substances from the other; integrating the heat of column C2 "and column C2 with an appropriate choice of column pressure in such a way that the condenser of one of the columns is a reboiler of the other, preferably column C2, operating at a higher pressure than column C2", so that the condenser of column C2 can be reboiler columns C2 '' '. More Preferred Savings Requirements

- 22,024,187 energy is achieved by integrating the heat of the column C2 ″ ″ and the column C2, as indicated above.

Fraction P2 can be introduced into column C2 ″ ″ during stage δ2 ″ ″ as a single fraction or as several sub-fractions. It is preferably administered as a single fraction.

According to the second embodiment of step e), step δ2 ″ ″ is preferably carried out at an absolute pressure of at least 5x10 ⁵ Pa (5 bar), preferably at least 10x10 ⁵ Pa (10 bar) and particularly preferably at least 12x10 ⁵ Pa ( 12 bar) The step δ2 ″ ″ is preferably carried out at an absolute pressure of at most 40x10 ⁵ Pa (40 bar), preferably at most 38x10 ⁵ Pa (38 bar) and particularly preferably at most 36x10 ⁵ Pa (36 bar).

According to the second variant of stage e), the temperature at which stage δ2 ″ is carried out is advantageously at least -50, preferably at least -40, and particularly preferably at least -30 ° C at the bottom of the stripping section of the column C2 ″ '. It is preferably at most 80, preferably at most 60 and particularly preferably at most 55 ° C at the bottom of the stripping section of the column C2 ″ ″.

According to the second embodiment of step e, the temperature at which step δ2 ″ is carried out is advantageously at least -70, preferably at least -60 and particularly preferably at least -55 ° C at the upper part of the rectification section of the column C2 ′ ''. It is preferably at most 0, preferably at most -15, and particularly preferably at most -25 ° C at the top of the rectification section of the column C2 ″ ″.

Before its introduction into column C2, fraction P2 'can be subjected to a heat conditioning stage, as indicated for stage δ1, and a pressure conditioning stage by pumping liquid obtained from the lower part of the stripping section of column C2' into column C2.

The column C2 is advantageously provided with connected auxiliary elements, such as, for example, at least a heating source and a cooling source with the same characteristics as the characteristics indicated for the column C2 ″ ″ in the context above.

The P2 ′ fraction can be introduced into the C2 column during the δ2 stage as one fraction or as several subfractions. It is preferably administered as a single fraction.

According to the second embodiment of step e), step δ2 is advantageously carried out at an absolute pressure of at least 5x10 ⁵ Pa (5 bar), preferably at least 10x10 ⁵ Pa (10 bar) and particularly preferably at least 12x10 ⁵ Pa (12 bar). Stage δ2 is preferably carried out at an absolute pressure of at most 40x 10 ⁵ Pa (40 bar), preferably at most 38x10 ⁵ Pa (38 bar) and particularly preferably at most 36x10 ⁵ Pa (36 bar).

According to the second embodiment of step e), step δ2 is preferably carried out at a pressure equal to or different from the pressure at which step δ2 ″ ″ is carried out. Stage δ2 is preferably carried out at a pressure other than the pressure at which stage δ2 ″ ″ is carried out. Stage δ2 is preferably carried out at a pressure higher than the pressure at which stage δ2 ″ ′ is carried out. Stage δ2 is carried out at a pressure that is preferably at least 2x10 ⁵ Pa (2 bar), more preferably at least 4x 10 ⁵ Pa (4 bar), most preferably at least 5x10 ⁵ Pa (5 bar) more, than the pressure at which carry out the stage δ2 "". Stage δ2 is carried out at a pressure that is preferably at most 33x10 ⁵ Pa (33 bar), more preferably at most 30x10 ⁵ Pa (30 bar), most preferably at most 20x10 ⁵ Pa (20 bar) more than the pressure, with which conduct stage δ2 "".

According to the second embodiment of step e), the temperature at which step δ2 is carried out is preferably at least -50, preferably at least -40, and particularly preferably at least -30 ° C at the bottom of the stripping section of the column C2. It is preferably at most 80, preferably at most 60 and particularly preferably at most 55 ° C at the bottom of the stripping section of the column C2.

According to the second embodiment of step e), the temperature at which step δ2 is carried out is advantageously at least -80, preferably at least -70 and particularly preferably at least -65 ° C at the upper part of the rectification section of the column C2. It is preferably at most 0, preferably at most -15, and particularly preferably at most -25 ° C at the top of the rectification section of column C2.

According to the two embodiments of step e) described above, the heavy fraction can be extracted to obtain a single fraction or several fractions, preferably two fractions, more preferably a fraction in a gaseous state enriched in ethane, preferably extracted in the lower third of the stripping section of the column, and a fraction in liquid state, depleted in ethane, preferably extracted from the bottom of the stripping section of the column.

The second variant of the first embodiment is preferable as compared with the second embodiment and as compared with the first variant of the first embodiment. The second sub-variant of the second variant of the first embodiment is preferable in

- 23 024187 compared with the first sub-variant of the second variant of the first embodiment. The second embodiment is preferred over the first embodiment of the first embodiment.

The quantities indicated below for characterizing the E2 fraction are the quantities at the outlet of the separation stage §2.

Fraction E2 is predominantly characterized by a volume content of combustible gases other than ethylene, preferably lower than 20%, preferably lower than 15%, and more preferably lower than 12%.

Fraction E2 is predominantly characterized by a hydrogen content that is less than or equal to 2%, preferably less than or equal to 0.5%, and in a particularly preferred method is less than or equal to 0.1% by volume relative to the total volume of fraction E2.

The E2 fraction is preferably characterized by an inert gas content that is less than or equal to 2%, preferably less than or equal to 0.5%, and in a particularly preferred method is less than or equal to 0.1% by volume relative to the total volume of the E2 fraction.

Fraction E2 is predominantly characterized by a volume content of oxidized compounds which is less than 2%, preferably less than 1% and more preferably less than 0.8%.

Fraction E2 is advantageously characterized by a volume content of oxygen which is less than 1.8%, preferably less than 1% and more preferably less than 0.8%.

Fraction E2 is advantageously characterized by a volume content of nitrogen oxides which is less than 0.00025%, preferably less than 0.0002% and more preferably less than 0.00015%.

Fraction E2 is advantageously characterized by a volume content of corrosive compounds which is less than 0.2%, preferably less than 0.1% and more preferably less than 0.08%.

Fraction E2 is advantageously characterized by a volume content of hydrogen sulphide which is less than 0.005%, preferably less than 0.001% and more preferably less than 0.0005%.

Fraction E2 is predominantly characterized by a volume content of reactive compounds which is less than 2%, preferably less than 1%, and more preferably less than 0.8%.

Fraction E2 is predominantly characterized by a volume content of reactive compounds other than carbon monoxide, which is less than 0.02%, preferably less than 0.01%, and more preferably less than 0.005%.

Fraction E2 is preferably characterized by a volume content of acetylene which is less than 0.2%, preferably less than 0.1%, more preferably less than 0.05%, and most preferably less than 0.02%.

The E2 fraction is characterized by a content of compounds containing at least 3 carbon atoms, which is preferably less than or equal to 0.01%, preferably less than or equal to 0.005%, and in a particularly preferred method less than or equal to 0.001% by volume relative to the total volume of the E2 fraction.

Fraction E2 is predominantly characterized by a volume content of compounds that poison the catalyst, which is less than 0.001%, preferably less than 0.0005% and more preferably less than 0.0002%.

The E2 fraction mainly contains from 60 to 99.5% by volume of ethylene relative to the total volume of the E2 fraction. Fraction E2 advantageously contains at least 60%, preferably at least 70%, in a particularly preferred method at least 80% and in a more particularly preferred method at least 85% by volume of ethylene relative to the total volume of fraction E2. Fraction E2 advantageously contains at most 99.5%, preferably at most 98.5%, in a particularly preferred method at most 97.5% and in a more specifically preferred method at most 96% by volume of ethylene relative to the total volume of fraction E2. Therefore, fraction E2 is characterized in that it contains predominantly at least 4%, preferably at least 2.5%, more preferably at least 1.5% and most preferably at least 0.5% of compounds other than ethylene. , relative to the total volume of the E2 fraction.

The quantities indicated below for characterizing the fractions Е2а and Е2Ь are the quantities at the outlet of the separation stage §2.

Fraction Е2а is mainly characterized by a volume content of combustible gases, other than ethylene, preferably less than 20%, preferably less than 15% and more preferably less than 12%.

Fraction Е2а is mainly characterized by a hydrogen content that is less than or equal to 2%, preferably less than or equal to 0.5%, and in a particularly preferred method is less than or equal to 0.1% by volume relative to the total volume of fraction E2.

The fraction Е2а is mainly characterized by the content of inert gases, which is less or

- 24 024187 is equal to 2%, preferably less than or equal to 0.5% and in a particularly preferred method is less than or equal to 0.1% by volume relative to the total volume of fraction E2.

Fraction Е2а is mainly characterized by the volume content of oxidized compounds, which is less than 2%, preferably less than 1% and more preferably less than 0.8%.

The fraction E2a is preferably characterized by a volume content of oxygen which is less than 1.8%, preferably less than 1% and more preferably less than 0.8%.

The fraction E2a is preferably characterized by a volume content of nitrogen oxides which is less than 0.00025%, preferably less than 0.0002% and more preferably less than 0.00015%.

The fraction E2a is preferably characterized by a volume content of compounds that cause corrosion, which is less than 0.02%, preferably less than 0.01% and more preferably less than 0.008%.

The fraction E2a is preferably characterized by a volume content of hydrogen sulphide which is less than 0.0005%, preferably less than 0.0001% and more preferably less than 0.00005%.

Fraction Е2а is mainly characterized by the volume content of reactive compounds, which is less than 0.2%, preferably less than 0.1% and more preferably less than 0.08%.

Fraction Е2а is mainly characterized by the volume content of reactive compounds, other than carbon monoxide, which is less than 0.002%, preferably less than 0.001% and more preferably less than 0.0005%.

The fraction E2a is preferably characterized by a volume content of acetylene which is less than 0.2%, preferably less than 0.1%, more preferably less than 0.05% and most preferably less than 0.02%.

Fraction Е2а is characterized by a content of compounds containing at least 3 carbon atoms, which is preferably less than or equal to 0.001%, preferably less than or equal to 0.0005%, and in a particularly preferred method is less than or equal to 0.0001%. relative to the total volume of the E2 fraction.

Fraction Е2а is mainly characterized by the volume content of compounds that poison the catalyst, which is less than 0.0001%, preferably less than 0.00005% and more preferably less than 0.00002%.

The fraction Е2а is mainly characterized by the ethylene content, which is the same with its content in the fraction Е2.

The fraction E2B is mainly characterized by a volume content of combustible gases other than ethylene, which is preferably less than 20%, preferably less than 15% and more preferably less than 12%.

Fraction E2B is mainly characterized by a hydrogen content that is less than or equal to 0.2%, preferably less than or equal to 0.05%, and in a particularly preferred method is less than or equal to 0.01% by volume relative to the total volume of fraction E2.

The E2B fraction is mainly characterized by an inert gas content that is less than or equal to 0.2%, preferably less than or equal to 0.05%, and in a particularly preferred method is less than or equal to 0.01% by volume relative to the total volume of the E2 fraction.

The fraction E2B is mainly characterized by the volume content of oxidized compounds, which is less than 0.2%, preferably less than 0.1% and more preferably less than 0.08%.

The fraction E2B is mainly characterized by a volume content of oxygen which is less than 0.18%, preferably less than 0.1% and more preferably less than 0.08%.

The fraction E2B is mainly characterized by the volume content of nitrogen oxides, which is less than 0.000025%, preferably less than 0.00002% and more preferably less than 0.000015%.

The fraction E2B is mainly characterized by the volume content of compounds that cause corrosion, which is less than 0.2%, preferably less than 0.1% and more preferably less than 0.08%.

The fraction E2B is mainly characterized by a volume content of hydrogen sulphide less than 0.005%, preferably less than 0.001% and more preferably less than 0.0005%.

The fraction E2B is mainly characterized by the volume content of reactive compounds, which is less than 2%, preferably less than 1% and more preferably less than 0.8%.

The E2B fraction is mainly characterized by the volume content of reactive compounds, other than carbon monoxide, less than 0.02%, preferably less than 0.01%, and more preferably less than 0.005%.

The fraction E2B is predominantly characterized by a volume content of acetylene less than 0.2%, preferably less than 0.1%, more preferably less than 0.05% and most preferably less than 0.02%.

The E2B fraction is characterized by a content of compounds containing at least 3 carbon atoms, which is preferably less than or equal to 0.01%, preferably less than or equal to 0.005%

- 25 024187 and in a particularly preferred method is less than or equal to 0.001% by volume relative to the total volume of the E2 fraction.

Fraction E2B is mainly characterized by the volume content of compounds that poison the catalyst, which is less than 0.001%, preferably less than 0.0005% and more preferably less than 0.0002%.

The E2B fraction is mainly characterized by the ethylene content, which is similar to its content in the E2 fraction.

The heavy fraction is enriched in ethane and a hydrocarbon containing at least 3 carbon atoms. Compounds containing at least 3 carbon atoms are formed from a mixture of products containing ethylene and other components obtained from step a). Among the compounds containing at least 3 carbon atoms, here you can specify propane, propylene, butane and their unsaturated derivatives, as well as all saturated or unsaturated heavier compounds.

Preferably, the heavy fraction contains at least 95%, preferably at least 98% and particularly preferably at least 99% of compounds containing at least 3 carbon atoms contained in the product mixture obtained from step a).

The heavy fraction preferably contains at most 1%, preferably at most 0.8% and particularly preferably at most 0.5% by weight of ethylene relative to the total weight of the heavy fraction.

The heavy fraction is predominantly enriched in components heavier than ethylene. The heavy fraction is preferably burned as a fuel or valorised chemically. More preferably, the heavy fraction is valorized chemically.

According to step ί), the E2 fraction or the E2a or E2b fraction are then directed to obtain at least one ethylene derivative, preferably to obtain an ESE, and optionally any compound formed from it, optionally after acetylene is subjected to hydrogenation, and to obtain at least one an ethylene derivative formed directly from ethylene, which differs from the EfE, and optionally any compound formed from it, more preferably for the preparation of EfE and optionally any compound, formed from it, optionally after acetylene is subjected to hydrogenation, most preferably either to the chlorination reactor and / or to the oxychlorination reactor, and in this reactor most of the ethylene present in fractions E2 or E2a and / or E2b is converted to OSE.

The resulting EfE is then preferentially in stage §) after stage ί) is separated from the product streams obtained from the chlorination and / or oxychlorination reactor and preferably in stage I) after stage e) is subjected to the cracking stage of the EfE to obtain a VC (vinyl chloride), which is then even more preferably in step ί) after step I) it is polymerized to produce PVC (RUS).

Before step ί), the E2 or E2a and / or E2b fractions are optionally subjected to acetylene hydrogenation followed by an optional drying stage, especially when sent to obtain EfE and optionally any compound formed from it. Fractions E2 or Е2а and / or Е2Ь are preferably subjected to acetylene hydrogenation when directed to obtain an EfE and optionally any compound formed from it. More preferably, the E2 or E2a and / or E2B fractions in the direction to obtain the EfE by direct chlorination are subjected to a stage of acetylene hydrogenation followed by a drying stage. More preferably, the fractions E2 or E2a and / or E2B, with the direction to obtain the EfE by oxychlorination, are subjected to the hydrogenation of acetylene without a drying step. In the latter case, the hydrogenation of the fraction enriched in ethylene can be carried out separately or simultaneously with the hydrogenation of hydrogen chloride separated from the product stream obtained by pyrolysis, before it is sent back to oxychlorination. The hydrogenation of the ethylene-enriched fraction is preferably carried out simultaneously with the hydrogenation of hydrogen chloride.

The hydrogenation of acetylene is preferably carried out as described previously for step a8a). Advantageously, in the case of such acetylene hydrogenation of the E2 or E2a and / or E2B fractions, the treated fractions are preferably characterized by a volume acetylene content of less than 0.01%, preferably less than 0.005%, more preferably less than 0.002% and most preferably less than 0.001%.

According to the first embodiment of step ί), the fraction E2 is preferably directed to obtain at least one ethylene derivative.

According to this first embodiment, the method according to the invention is advantageously such that, after steps a) to e), the fraction E2 is then sent to obtain at least one ethylene derivative, preferably to obtain an EfE and optionally any compound formed from it, optionally after hydrogenation acetylene in it, and to obtain at least one ethylene derivative, which is formed directly from ethylene and which differs from the EfE, and optionally any compound, nnogo thereof, more preferably for EFE and optionally of any compound formed therefrom, optionally after it is subjected to hydrogenation of acetylene.

According to the first variant of the first embodiment of the stage), the E2 fraction is predominantly transported as one fraction. 26 024187.

According to this first embodiment, the method according to the invention is advantageously such that after steps a) to e) the fraction E2 is sent as one fraction to obtain at least one ethylene derivative, or to obtain an EfE and optionally any compound formed from it, optionally after acetylene hydrogenation of this fraction, or to obtain at least one ethylene derivative, which is formed directly from ethylene and which differs from EfE, and optionally any compound, is formed for out of it.

The E2 fraction is preferably sent as a single fraction to obtain an EfE and optionally any compound formed from it, optionally after hydrogenating the acetylene fraction, either to the chlorination reactor or to the oxychlorination reactor, and in such a reactor most of the ethylene present in the E2 fraction is converted in the EfE.

The resulting OSE is then, more preferably in stage d) after stage £), is separated from the product streams obtained from the chlorination or oxychlorination reactor, and most preferably in stage I) after stage e) is subjected to the cracking stage of the OSE to obtain a VC (vinyl chloride), which then even more preferably in step ί), after step I), is polymerized to produce PVC (RUS).

This case is especially interesting when only one fraction is required for stage £).

According to the second variant of the first embodiment of the stage £), the fraction E2 is advantageously divided into at least two fractions of the same composition or different composition, preferably the fraction E2b 'and the fraction E2b of the same composition or different composition.

This latter case is especially interesting when different fractions, either of the same or of different composition, are required for stage) in order to direct them for the corresponding production of the ethylene derivative.

According to this second embodiment, the method according to the invention is advantageously such that, after steps a) to e) ί), the fraction E2 is divided into at least two fractions, preferably into fractions E2b 'and fraction E2b of the same composition or different composition before sent to obtain at least one ethylene derivative.

One fraction from fractions E2b 'and E2b is preferably directed to produce ESC and optionally any compound formed from it, optionally after hydrogenation of the acetylene fraction, while the other fraction is sent to obtain at least one ethylene derivative, which is derived directly from ethylene and which differs from ESE. and optionally any compound formed from it.

More preferably, the two fractions are sent to produce ESC and optionally any compound formed from it, optionally after acetylene is hydrogenated in them, one to the chlorination reactor and the other to the oxychlorination reactor, and in these reactors most of the ethylene present in each fraction is converted to ESE .

ECE. obtained by separating from product streams obtained from chlorination and oxychlorination reactors, then mainly in stage e) after stage ί) and preferably in stage I) after stage e) is subjected to a stage of cracking of the ECA to obtain a CA, which is then more preferably in stage) after stage I), polymerized to obtain PVC.

It is assumed that the term divided (or divided) in the expression fraction E2 divided into at least two fractions means for the purpose of the invention the division of the fraction E2 into two or more sub-mixtures in such a way that all sub-mixtures are characterized at a certain pressure range with a composition that is included in the range determined by the composition of the E2 fraction at the bubble point and the composition of the E2 fraction at the condensation point.

The expression boiling point is assumed to mean for the purpose of the invention such a point during the heating of the E2 fraction at constant pressure from the initial temperature, when the E2 fraction is in the liquid state and the first vapor bubble is formed; moreover, the composition of the fraction at the boiling point is the composition of this first vapor bubble.

The expression condensation point is assumed to mean for the purpose of the invention such a point during cooling of the P2 fraction at constant pressure from the initial temperature, when the P2 fraction is in the vapor phase and the first liquid drop is formed, and the composition of the fraction at the condensation point is the composition of this first liquid drop.

The separation of the E2 fraction into at least two fractions, preferably into the E2 'fraction and the E2 fraction, is advantageously carried out by dividing the E2 fraction into several, preferably two fractions of the same composition or of different composition by any known method.

The separation stage can be carried out on one or several devices. The separation stage mainly involves the separation operation. Examples of separation operations are the separation of a mixture into sub-mixtures having an identical composition, partial condensation of the gaseous mixture, partial evaporation of the liquid mixture, and partial curing of the liquid mixture.

The division of the E2 fraction into at least two fractions, preferably into the E2b 'fraction and the E2b fraction of different composition, can be carried out by any known method. The E2 fraction is predominantly cooled by direct cooling in a heat exchanger, where the E2 fraction is evaporated after expanding to a suitable pressure and supercooled by indirect contacting in a heat exchanger cooled by a suitable cooling medium, up to the indicated decrease in its temperature. The mixture of liquid vapors is preferably separated to obtain the E2B ′ vapor fraction and the E2B liquid fraction. The temperature reduction is carried out mainly by more than 5, preferably more than 7 and more preferably more than 8 ° C. The temperature reduction is preferably carried out lower than 30, preferably lower than 25 and more preferably lower than 22 ° C.

Fraction E2B 'preferably contains more than 10, preferably more than 20, and more preferably more than 25% of the amount of ethylene contained in fraction E2. Fraction E2B 'preferably contains less than 90, preferably less than 80, and more preferably less than 75% of the amount of ethylene contained in fraction E2.

Fraction E2B 'is predominantly enriched in hydrogen compared to fraction E2. The ratio of the molar concentration of hydrogen in the E2D 'fraction to the molar concentration of hydrogen in the E2B fraction is preferably above 25, preferably above 50 and more preferably above 60.

Fraction Е2Б 'is predominantly enriched in methane as compared with fraction E2. The ratio of the molar concentration of methane in the E2B 'fraction to the molar concentration of methane in the E2B fraction is preferably above 2.5, preferably above 4, and more preferably above 5.

The E2B fraction is predominantly depleted in ethane compared to the E2 fraction. The ratio of the molar concentration of ethane in the E2B 'fraction to the molar concentration of ethane in the E2B fraction is preferably below 0.9, preferably below 0.85, and more preferably below 0.8.

According to the second embodiment of step 1), the fractions E2a and E2B are preferably directed to obtain at least one ethylene derivative.

According to the second embodiment, the method according to the invention is advantageously such that after steps a) to e) in step 1) the fractions E2a and E2b are then sent to obtain at least one ethylene derivative, preferably to obtain an EfE and optionally any compound formed from it, optionally after acetylene hydrogenation of these fractions, and to obtain at least one ethylene derivative, which is formed directly from ethylene and differs from EfE, and optionally any compound Formed therefrom, preferably for EFE and optionally of any compound formed therefrom, optionally after treatment fractions for hydrogenation of acetylene.

According to the first variant of the second embodiment of stage 1), the fractions E2a and E2B are served separately.

According to this first embodiment, the process according to the invention is advantageously such that, after steps a) to e) in step 1), fractions E2a and E2B are served separately to obtain at least one ethylene derivative.

One fraction from fractions Е2а and Е2Ь is preferably fed to obtain an EfE and optionally any compound formed from it, optionally after treating it to hydrogenate acetylene, while the other fraction is fed to obtain at least one ethylene derivative, which is formed directly from ethylene, which differs from EfE, and not necessarily any compound formed from it.

More preferably, two fractions are fed to obtain an OEC and, optionally, any compound derived from it, optionally after hydrogenating the acetylene of these fractions, one fraction, preferably the fraction E2a, is fed to the chlorination reactor and the other, preferably the fraction E2b, to the oxychlorination reactor, in these reactors is large part of the ethylene present in each fraction is converted to EfE.

The formed EfE is then preferentially isolated in stage d) after stage 1) from the product streams obtained from the chlorination and oxychlorination reactors, and preferably in stage B) after stage e) is subjected to the cracking stage of the EfE to obtain the AC, which is then more preferably in stage) after stage B) is polymerized to obtain PVC.

This case is particularly interesting when, for stage 1), different fractions are required to direct them for the corresponding production of an ethylene derivative.

According to the second variant of the second variant of the implementation of stage 1), the fractions Е2а and Е2Ь are mixed before feeding them for transformation.

Fractions Е2а and Е2Ь can be mixed by any known means, such as, for example, a mixing tee, a static mixer, a compacted layer of inert particles, a sequence of perforated plates or holes, as well as a rotary device (pump or compressor).

According to this second embodiment, the method according to the invention is advantageously such that after steps a) to e) in step 1), the fractions E2a and E2B are mixed before feeding to obtain at least one ethylene derivative, or to obtain ESE and optionally any compound formed from it, optionally after the hydrogenation of acetylene, or to obtain at least one ethylene derivative, formed directly from ethylene, which differs from ESE, and optionally any compound formed from it.

- 28 024187

Fractions Е2а and Е2Ь are preferably mixed before feeding to produce an ESE and optionally any compound formed from it, optionally after hydrogenating acetylene, either into the chlorination reactor or into the oxychlorination reactor, and in such a reactor most of the ethylene present in fraction E2 is converted to ISE.

The resulting ECE is then, more preferably in stage d) after stage), separated from the product streams obtained from the chlorination reactor or the oxychlorination reactor, and most preferably in stage ι) after stage d) is subjected to the ISE cracking stage to give a CG, which then , still most preferably in stage ί) after stage Ιι). polymerized to produce PVC.

This case is especially interesting when only one fraction is required for stage ί).

As examples of ethylene derivatives obtained directly from ethylene, which differ from ECE and which can be obtained according to the embodiments described above, ethylene oxide, non-branched alpha-olefins, unbranched primary alcohols, homopolymers and copolymers of ethylene, ethylbenzene, vinyl acetate, acetaldehyde, ethyl alcohol and propionaldehyde. Preference is given to the production of ethylbenzene and particular preference is given to the production of ethylbenzene itself, supplied for the production of styrene, then polymerized for the production of styrene polymers.

As examples of an optional compound obtained from another ethylene derivative, among others are glycols obtained from ethylene oxide, styrene obtained from ethylbenzene, and styrene polymers obtained from styrene.

The chlorination reaction (commonly referred to as direct chlorination) is preferably carried out in the liquid phase (preferably mainly in ECE) containing a dissolved catalyst, such as HeCl ₃ or another Lewis acid. This catalyst can advantageously be combined with cocatalysts, such as alkali metal chlorides. The pair that gave good results is the complex HerC1 ₃ with LIC1 (lithium tetrachloroferrate - as described in Dutch patent application 6901398).

The amounts of EEC1 ₃ used predominantly are approximately 1-30 g EEG1 ₃ per kg of the initial liquid. The molar ratio of EHCl ₃ to NCl is preferably in the range of 0.5–2.

In addition, the chlorination reaction is preferably carried out in an environment of chlorinated organic liquid. More preferably, this chlorinated organic liquid medium, also called liquid feedstock, is mainly composed of ECE.

The chlorination reaction according to the invention is preferably carried out at a temperature between 30 and 150 ° C. Good results were obtained regardless of pressure, both at a temperature below the boiling point (chlorination method under supercooling conditions) and at the boiling point itself (chlorination method at boiling point).

When the method of chlorination according to the invention is a method of chlorination under supercooled conditions, it gives good results when carrying out the reaction at a temperature that is preferably greater than or equal to 50 ° C and preferably greater than or equal to 60 ° C, but preferably less than or equal to 80 ° C and preferably lower or equal to 70 ° C, and at an absolute pressure in the gas phase, which is preferably greater than or equal to 1x 10 ⁵ Pa (1 bar) and preferably greater than or equal to 1.1 χ 10 ⁵ Pa (1.1 bar), but preferably less than or equal to 20x10 ⁵ Pa (20 bar), preferred less than or equal to 10x10 ⁵ Pa (10 bar) and particularly preferably less than or equal to 6x 10 ⁵ Pa (6 bar).

The method of chlorination at the boiling point can be carried out for the useful recovery of the heat of reaction. In this case, the reaction preferably takes place at a temperature that is greater than or equal to 60 ° C, preferably greater than or equal to 70 ° C and particularly preferably greater than or equal to 85 ° C, but preferably lower than or equal to 150 ° C and preferably lower than or equal to 135 ° C, and with an absolute pressure in the gaseous phase, which is preferably greater than or equal to 0.2 x 10 ⁵ Pa (0.2 bar), preferably greater than or equal to 0.5 x 10 ⁵ Pa (0.5 bar), particularly preferably greater than or equal to 1, 1 χ 10 ⁵ Pa (1.1 bar) and more specifically preferably higher than or equal to 1.3 x 10 ⁵ Pa (1.3 bar), but mainly o less than or equal to 10x10 ⁵ Pa (10 bar) and preferably less than or equal to 6x 10 ⁵ Pa (6 bar).

The chlorination method can also be a chlorination method at the boiling point with a hybrid revolving cooling. It is assumed that the expression chlorination method at the boiling point with hybrid rotational cooling means a method in which the cooling of the reaction medium is carried out, for example, using an exchanger immersed in the reaction medium, or circulating circulation in the exchanger, and at least in some amounts of ECE. The temperature and pressure of the reaction are advantageously controlled in order to leave the formed EEC in the gaseous phase and in order to remove the remaining heat from the reaction medium using the surface area of the exchanger.

The fraction subjected to chlorination, as well as molecular chlorine (as such or diluted) can be introduced, together or separately, into the reaction medium by any known device. Separate introduction of the fraction subjected to chlorination may be preferential to increase its partial pressure and facilitate its dissolution, which often constitutes the limiting stage of the process.

Molecular chlorine is added in an amount sufficient to convert most of the ethylene and without the need to add an excess of unconverted chlorine. The chlorine / ethylene ratio used is preferably between 1.2 and 0.8, and particularly preferably between 1.05 and 0.95 mol / mol.

The resulting chlorinated products contain mostly ΌΟΕ, as well as small amounts of by-products, such as 1,1,2-trichloroethane, or small amounts of chlorination products of ethane or methane.

Isolation of the resulting ΌΟΕ from the stream of products obtained from the chlorination reactor is carried out according to known methods, and this separation usually makes it possible to use the heat of the chlorination reaction. It is then preferably carried out by condensation and gas / liquid phase separation.

Unconverted products (methane, ethane, carbon monoxide, nitrogen, oxygen, and hydrogen) are then preferentially easier to isolate than the precipitate that may be necessary to separate pure ethylene from the original mixture.

Hydrogen, in particular, can be extracted from unconverted products and burned as fuel or valorized chemically, for example, to hydrogenate the working solution when producing hydrogen peroxide or to directly synthesize hydrogen peroxide.

The oxychlorination reaction is preferably carried out in the presence of a catalyst containing active elements, including copper, deposited on an inert carrier. The inert carrier is preferably selected from alumina, silica gels, mixed oxides, clays, and other carriers of natural origin. Alumina is the preferred inert carrier.

Preferred are catalysts containing active elements, which are preferably at least two elements, one of which is copper. Among the active elements other than copper, you can specify alkali metals, alkaline earth metals, rare earth metals and metals from the group consisting of ruthenium, rhodium, palladium, osmium, iridium, platinum and gold. Catalysts containing the following active elements are particularly preferred: copper / magnesium / potassium, copper / magnesium / sodium, copper / magnesium / lithium, copper / magnesium / cesium, copper / magnesium / sodium / lithium, copper / magnesium / potassium / lithium and copper / magnesium / cesium / lithium, copper / magnesium / sodium / potassium, copper / magnesium / sodium / cesium, and copper / magnesium / potassium / cesium. The catalysts described in patent applications EP A 255156, EP A 494474, EP A 657212 and EP A 657213 are most particularly preferred.

The copper content calculated in the form of a metal is preferably 30-90 g / kg, preferably 40-80 g / kg, and particularly preferably 50-70 g / kg of the catalyst.

The magnesium content calculated in the form of a metal is preferably 10-30 g / kg, preferably 12-25 g / kg, and particularly preferably 15-20 g / kg of catalyst.

The alkali metal content calculated in the form of a metal is preferably 0.130 g / kg, preferably 0.5 to 20 g / kg, and particularly preferably 1-15 g / kg of the catalyst.

The atomic ratio of Cu: Md: alkali metal (s) is preferably 1: 0.1-2: 0.05-2, preferably 1: 0.2-1.5: 0.1-1.5, and particularly preferably 1: 0.5-1: 0.15-1.

Catalysts having a specific surface area, measured according to method ΒΕΤ with nitrogen and preferably from 25 to 300 m ² / g, preferably from 50 to 200 m ² / g and particularly preferably from 75 to 175 m ² / g, are particularly suitable.

The catalyst can be used in a fixed bed or in a fluidized bed. This second option is preferred. The oxychlorination process is carried out in the range of conditions normally recommended for this reaction. The preferred temperature is 150-300 ° C, preferably 200-275 ° C and most preferably 215-255 ° C. The predominant pressure is above atmospheric pressure. Absolute pressure values between 2 and 10x10 ⁵ Pa (2 and 10 bar) give good results. The absolute pressure range between 4 and 7x10 ⁵ Pa (4 and 7 bar) is preferred. This pressure can be suitably adjusted in order to achieve an optimum residence time in the reactor and maintain a constant transmission rate for various operating speeds. The usual range of residence times is from 1 to 60 s and preferably from 10 to 40 s.

The oxygen source for this oxychlorination can be air, pure oxygen, or a mixture of them, preferably pure oxygen. The latter source, which easily allows recycling of unconverted reagents, is preferred.

Reagents can be injected into the bed with any known device. It is usually advantageous to introduce oxygen separately from other reagents for safety reasons. These safety reasons also require that the gaseous mixture leaving the reactor or recycled to it is kept outside the limits of flammability at the pressures and temperatures under consideration. It is preferable to maintain a so-called rich mixture, i.e., containing too little oxygen relative to the fuel that ignites. In this regard, the excessive presence (> 2% by volume, preferably> 5% by volume) of hydrogen may result in the disadvantage of which is wide

- 30 024187 flammability range of this compound.

The hydrogen chloride / oxygen ratio used is preferably between 3 and 6 mol / mol. The ethylene / hydrogen chloride ratio is preferably between 0.4 and 0.6 mol / mol.

The chlorinated products obtained contain mainly EfE as well as small amounts of by-products such as 1,1,2-trichloroethane.

The EfE isolated from the product streams obtained from the chlorination reactor may or may not be mixed with the EfE extracted from the streams obtained from the oxychlorination reactor before the cracking stage of the EfE. When both EfEs are mixed, they can be mixed completely or partially.

The conditions under which the cracking of the EfE can be carried out are known to those skilled in the art. The cracking of the EfE can be carried out in the presence or in the absence of third compounds, among which catalysts can be indicated; cracking the EfE in this case is a catalytic cracking of the EfE. The cracking of the EfE, however, is preferably carried out in the absence of third compounds and under the action of heat only; cracking of the EfE in this case is often called pyrolysis.

This pyrolysis is mainly carried out by the reaction in the gaseous phase in a tube furnace. Typical pyrolysis temperatures are between 400 and 600 ° C, with a preference for the range between 480 and 540 ° C. The residence time is preferably 1-60 s with a preference for the range from 5 to 25 s. The degree of conversion of the EfE is mainly limited to a limit of 45 to 75% to limit the formation of by-products and clogging of the furnace tubes.

Isolation of the formed ES and hydrogen chloride from the product stream obtained by pyrolysis, is carried out according to known methods using any known device for collecting purified ES and hydrogen chloride. After cleaning, the unconverted EfE is preferably sent to the pyrolysis furnace.

The CA is then preferably polymerized to produce PVC.

The production of PVC can be carried out by a method of polymerization in bulk, solution or aqueous dispersion, the method of polymerization in aqueous dispersion is preferred.

It is assumed that the expression polymerization in aqueous dispersion means free radical polymerization in aqueous suspension, as well as free radical polymerization in aqueous emulsion and polymerization in aqueous microsuspension.

The expression free radical polymerization in aqueous suspension is assumed to mean any method of free radical polymerization conducted in an aqueous medium in the presence of dispersing agents and free radical initiators soluble in oil.

The expression free radical polymerization in an aqueous emulsion is assumed to mean any method of free radical polymerization carried out in an aqueous medium in the presence of emulsifying agents and water-soluble free radical initiators.

It is assumed that the expression polymerization in aqueous microsuspension, also called polymerization in a homogeneous aqueous dispersion, means any free radical polymerization method that uses oil-soluble initiators and an emulsion of monomer droplets by powerful mechanical mixing in the presence of emulsifying agents.

The first embodiment of the implementation of the stage £) is preferable to the second embodiment.

The characteristic of the method according to the invention is that it is carried out predominantly during all its stages, preferably stages b), c) and e), more preferably stages b) and c), at a temperature advantageously at least -110, preferably at least -105 and particularly preferably at least -100 ° C.

A preferred method according to the invention is a method for producing at least one ethylene derivative from a low-value residual gas, according to which:

a) a low-value residual gas containing fraction E1 recycled from stage подверга) is subjected to a number of processing steps in a low-value residual gas utilization unit to remove unwanted components present in it and to obtain a mixture of products containing ethylene and other components;

b) the mixture of products is subjected to the first stage of dividing §1, which consists in dividing said products containing ethylene and other components into a fraction containing compounds that are lighter than ethylene, and part of ethylene and called fraction P1, and into fraction P2;

c) the P1 fraction is sent to an ethylene separation unit in which it is divided into a fraction enriched in ethylene and called an E1 fraction, and a fraction enriched in compounds that are lighter than ethylene and called the light fraction;

ά) the E1 fraction is recycled to step a);

e) the P2 fraction is subjected to the second stage of the separation of §2, which consists in separating the P2 fraction in one or two separations into one fraction enriched in ethylene and called fraction E2, and into a fraction enriched in ethane and a hydrocarbon containing at least 3 carbon atoms, and called the heavy fraction;

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ί) E2 fraction is then sent to obtain at least one ethylene derivative.

A particularly preferred method according to the invention is a method for producing 1,2 dichloroethane from a low-value residual gas, comprising steps a) to ί) described in the context above, according to which 1,2-dichloroethane is an ethylene derivative.

The first advantage of the method according to the invention is that it allows the use of ethylene with a purity of less than 99.8%.

Another advantage of the method according to the invention is that it allows the utilization and conversion of a gas stream that contains significant amounts of ethylene and / or its predecessor (s) and which was previously characterized by low valorization (low-value residual gas).

Another advantage of the method according to the invention is that it does not contain a cracking stage with subsequent organic and aqueous quenching stages, nor a catalytic oxidisation stage, which require a significant investment, which causes an increase in the cost of production and which includes the use of expensive hydrocarbon sources.

The advantage of the method according to the invention in comparison with the methods described in the prior art is that it does not require separation into two ethylene fractions, which differ in the ethylene content and the conditions of use of which are different, which can make unsuitable methods in which then used, and which may limit their use due to reactive impurities that they contain, for example, hydrogen, which is unacceptable in the oxychlorination method of ethylene.

Other advantages that can be attributed to the method according to the invention are the advantages associated with the fact that compounds that are lighter than ethylene are separated from the ethylene fraction. Among them, it is possible to indicate the advantage of carrying out the method in the apparatus, the size of which is not necessary to increase, and the elimination of losses during stripping, which reduce the efficiency of the method.

The method according to the invention by allowing the separation of the fraction enriched in compounds lighter than ethylene leads to their easier valorization.

Another advantage of this method is that it makes it possible to separate compounds containing at least 3 carbon atoms through a heavy fraction, these compounds are usually responsible for some unwanted side reactions leading to the formation of undesirable compounds that are difficult to separate.

Finally, an advantage of the method according to the invention is that it makes it possible to carry out a fully integrated process on the same industrial installation.

Preferred and particularly preferred methods according to the invention will now be illustrated with reference to the drawing accompanying the present description. This drawing consists of the attached FIG. 1, schematically representing a preferred method according to the invention for producing at least one ethylene derivative and a particularly preferred method according to the invention for producing 1,2-dichloroethane.

Low-value residual gas (1) containing recycled E1 fraction (2) is subjected to a series of processing steps in a low-value residual gas utilization unit (3) to remove unwanted components present in it and to obtain a mixture of products containing ethylene and other components ( four). This mixture (4) is subjected to the first stage of the separation of §1 (5), which consists of separating said mixture into a fraction containing compounds that are lighter than ethylene and part of ethylene, and called fraction P1 (6), and into fraction P2 (7 ). Fraction P1 (6) is then sent to an ethylene extraction unit (8), in which it is divided into an ethylene-enriched fraction and called an E1 fraction (2), which is recycled to the first stage, and to an enriched fraction that is lighter than ethylene , and called the light fraction (9). The P2 (7) fraction is subjected to the second stage of the separation of §2 (7), which consists of separation, in one or two divisions, of the P2 (7) fraction into one fraction enriched in ethylene and called the E2 fraction (11), and into the fraction enriched ethane and a hydrocarbon containing at least 3 carbon atoms, and called the heavy fraction (12). Fraction E2 (11) is then sent to obtain at least one ethylene derivative and preferably according to a particularly preferred method according to the invention to obtain 1,2-dichloroethane, which can then (not shown in the figure) be cracked to produce vinyl chloride, which can then be polymerized to obtain polyvinyl chloride.

Claims (9)

1. A method of producing 1,2-dichloroethane (ISE) from a low-value residual gas, according to which: a) the low-value residual gas and the E1 fraction recirculated from stage b) are subjected to a series of randomly processed processing steps in a low-value residual gas utilization unit to remove undesirable components present in it, where these stages include: A1) the removal of corrosive compounds, a2) the removal of compounds poisoning the catalyst, to obtain a mixture of products containing ethylene; - 32 024187 b) said product mixture is subjected to a first separation step §1, which consists of separating said products containing ethylene into a fraction P1 containing compounds that are lighter than ethylene and part of ethylene and into a fraction P2; c) the P1 fraction is directed to an ethylene recovery unit in which it is separated into an E1 fraction enriched in ethylene and a light fraction enriched in compounds that are lighter than ethylene, which contains less than 2 vol.% ethylene and which is burned as fuel or chemically valorized; g) fraction E1 is recycled to stage a); f) the P2 fraction is subjected to the second separation step, §2, which consists of separating the P2 fraction into one E2 fraction enriched in ethylene and into a heavy fraction enriched in ethane and a hydrocarbon containing at least 3 carbon atoms; £) fraction E2 is then sent to obtain 1,2-dichloroethane (OCE), the low-value residual gas being a gas or a mixture of several gases containing ethylene and / or its precursors, where the precursors mean any hydrocarbon compounds containing two carbon atoms other than ethylene, which is the waste gas obtained as a by-product in the device for producing at least one combustible liquid, the low-value residual gas consisting of more than 10 wt.% gas, the critical temperature of which about lower than 0 ° C and which cannot be liquefied by simple compression, while the E2 fraction is characterized by a hydrogen content that is less than or equal to 2 vol.% relative to the total volume of the E2 fraction, and contains from 60 to 99.5 vol.% ethylene relative to the total volume fraction E2. 2. The method according to claim 1, characterized in that when processing a low-value residual gas in a low-value residual gas utilization plant, an additional dust removal, compression, cooling step, at least partial removal of a certain amount of combustible and inert gases, oxidized compounds and reactive compounds. 3. The method according to claim 1, characterized in that the low-value residual gas is the exhaust gas of an oil refinery or oil refinery. 4. The method according to claim 3, characterized in that the exhaust gas of a refinery or oil refinery is obtained in at least one catalytic cracking unit with a fluidized catalyst. 5. The method according to any one of claims 1 to 4, characterized in that the low-value residual gas is a mixture of several gases containing ethylene and / or its precursor (s), and contains from 10 to 60 wt.% Ethylene. 6. The method according to claim 5, characterized in that the low-value residual gas is characterized by low calorific value, comprising from 20 to 75 MJ / kg of dry gas. 7. The method according to claim 1, characterized in that ί) the E2 fraction is directed to obtain 1,2-dichloroethane (OCE) and optionally any compound formed from it, optionally after it is subjected to treatment for the hydrogenation of acetylene, and for obtaining at least one derivative of ethylene formed directly from ethylene and different from 1,2-dichloroethane (OCE), and optionally any compound formed from it. 8. The method according to claim 1, characterized in that ί) the E2 fraction is directed to obtain 1,2-dichloroethane (OCE) and optionally any compound formed from it, optionally after processing it to hydrogenate acetylene. 9. The method according to claim 1, characterized in that the light fraction is chemically valorized.