RU2548955C1 - Method of airing and stabilisation of unstable gas condensate in mixture with oil with absorption extraction of mercaptans - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: method and device of airing and stabilisation of an unstable gas-condensate in a mixture with oil with the absorption extraction of mecraptans include two successively working separation columns, equipped with contact and discharge devices, introduction of the first irrigation into the lower part and liquid irrigation into the upper part of the columns and the discharge of stable and purified residues from the bottom of the columns. An initial mixture of the unstable gas-condensate and oil is subjected to airing and is supplied into the first rectification column-stabiliser. The stable mixture of the gas-condensate with oil from the bottom of the first rectification column-stabiliser is supplied into the second rectification column, from the top of which removed are hydrocarbon fractions, which contain extracted further as odorants isomeric ethylmercaptan and normal propylmercaptans and isomeric and normal butylmercaptans or mixtures of respective mercaptans. From the bottom of the second rectification column removed is a heavy residue, a part of which is supplied in the upper part of the third absorption column as an absorbent for absorbing the remaining heavy mercaptans from airing gases, discharged from the top of separators, and a stabilisation gas, discharged from the top of the first stabilisation column, supplied into the third absorption column, from the bottom of which the absorbent saturated with heavy mercaptans is supplied as a recirculate into the middle part of the first stabilisation column.EFFECT: invention makes it possible to purify oil in a mixture with the gas-condensate from mercaptan and produce a broad assortment of hydrocarbon fractions.12 cl, 3 dwg

Description

The invention relates to the field of preliminary processing of unstable gas condensate mixed with oil and can be used in the oil refining industry in the production of odorants.

The light fractions of an unstable gas condensate mixed with oil contain low molecular weight mercaptans: methyl mercaptan, ethyl mercaptan, isomeric and normal propyl mercaptans, and isomeric and normal butyl mercaptans. One of the features of mercaptans is the unpleasant odor transmitted by them to oil products and worsening the commodity quality of the latter, which requires cleaning, that is, demercaptanization of the latter. In accordance with the requirements of the standard for oil and gas condensate, the residual content of hydrogen sulfide and the amounts of methyl mercaptan and ethyl mercaptan should not exceed 20 and 40 ppm, respectively. On the other hand, mercaptans, with the exception of methyl mercaptan, serve as odorants added to natural fuel gas as indicators for detecting emergency gas leaks; therefore, when stabilizing gas condensate, oil and their mixtures, it is advisable to extract ethyl mercaptan as an independent product.

A known method of separating gas condensate in two sequentially operating distillation columns, in the first of which the condensate is stabilized, and in the second stable condensate is divided into light gasoline and diesel fractions (patent RU 2114892, IPC B01D, C10G, filed 07.10.1996, published 10.07.1998 ) The main disadvantages of the invention are:

- stabilization gases discharged from the first distillation column are irrationally used as fuel gas;

- mercaptans remaining in light gasoline and diesel fractions worsen the organoleptic qualities of petroleum products;

- the separation of stable condensate into light gasoline and diesel fractions without additionally extracting an intermediate kerosene fraction leads to a deterioration in the quality of both gasoline and diesel fractions.

A known method of stabilizing hydrogen sulfide and mercaptan-containing oil in the preparation of oil for transportation by distillation in two successive distillation columns at a pressure of 0.1-0.2 MPa and an oil heating temperature of 120-160 ° C, the distillates of which are stabilization gas and condensate ( patent RU 2409609, IPC C10G, filed August 5, 2009, published January 20, 2011). The main disadvantage of the invention is that when oil is stabilized, hydrogen sulfide, light mercaptans and low molecular weight hydrocarbons are simultaneously removed from the oil, which can then be used as factory fuel gas, during the combustion of which sulfur compounds give sulfur oxides that pollute the environment, and heavy mercaptans remain in stable oil, worsening its quality.

There is also known a method of processing gas condensates, including stabilization of unstable gas condensate, topping of stabilization gases to obtain a wide fraction of light hydrocarbons, atmospheric distillation of stable gas condensate, hydrotreating of the obtained fractions, separation of hydrotreating products into fractions followed by catalytic reforming, characterized in that the hydrotreating products are separated on the fractions nk-70 ° C, 70-180 ° C and 180-350 ° C, followed by catalytic reforming of the fraction 70-180 ° C, hydrotreated fr ktsiyu nc-70 ° C is subjected to isomerization and wide fraction of light hydrocarbons - flavoring components to obtain high-octane gasoline, the atmospheric residue is subjected to catalytic cracking (patent RU 245337, IPC C10G, pending 12.07.1996, published 10.02.2000). The main disadvantages of the invention are:

- stabilization gases are cleaned of sulfur compounds and stripped by oil absorption to obtain fuel gas and a wide fraction of light hydrocarbons, which leads to the presence of sulfur compounds in the fuel gas, which, when the gas is burned, transform into sulfur oxides polluting the environment;

- heavy mercaptans remain in a stable gas condensate and in the course of its subsequent distillation pass into fractions subjected to hydrotreating, which on the one hand leads to an additional load on hydrotreating catalysts, and on the other hand, to the destruction of mercaptans, which are valuable odorants.

There is also a method of deodorizing purification of oil and gas condensate from hydrogen sulfide and mercaptans by oxidizing them with atmospheric oxygen under pressure in the presence of an aqueous solution of monoethanolamine at a temperature of 10-65 ° C, characterized in that the process is carried out in the presence of elemental sulfur, taken in the form of 0.1 -20% solution in a 20-99% aqueous solution of monoethanolamine, this solution in an amount of 0.02-25% of the mass. for raw materials and air in an amount of 0.08-0.15 nm ³ per 1 mol of hydrogen sulfide and 2 moles of mercaptan sulfur are introduced into oil or gas condensate with stirring and the mixture is kept at a pressure of 0.2-3.5 MPa for at least 5 minutes (Patent RU 2140960, IPC C10G, filed January 16, 1997, published November 10, 1999).

The main disadvantages of the invention are:

- the need to introduce elemental sulfur into the cleaned system;

- the required amount of sulfur in a fresh monoethanolamine solution is determined only empirically;

- mercaptans turn into disulfides and remain as sulfur-containing components in the refined oil and gas condensate.

There is also a method of deodorizing purification of oil and gas condensate from hydrogen sulfide and low molecular weight mercaptans, which includes continuously introducing into the raw material the calculated amounts of an aqueous-alkaline solution of the catalyst and air, keeping the mixture at a pressure of 0.5-3.0 MPa and a temperature of 25-65 ° C and separation of the reaction mixture with the release of purified raw materials. In this method, the feed stream without preliminary purification from hydrogen sulfide with stirring simultaneously injected 25-45% aqueous solution of alkali and 0.15-0.25% solution of phthalocyanine catalyst in purified water from dissolved oxygen or 0.5-1.5% aqueous solution alkali, then air is introduced into the feed stream, the resulting mixture is kept for 5-180 minutes, after which part of the reaction mixture containing purified feed, dissolved exhaust air and an emulsified aqueous-alkaline solution of the catalyst is directed to mixing with the feedstock, to Thoroe conducted at a pressure of 0.2-0.5 MPa (patent RU 2120464, IPC C10G, pending 12.09.1997, published 20.10.1998). The main disadvantages of the invention are:

- from the purified raw material, a water-salt solution is deposited, containing mainly sodium thiosulfate, as well as small amounts of sulfate, caustic soda and catalyst, which increases the amount of production effluents to be treated;

- the main oxidation product of sulfur-containing compounds contains elemental sulfur, which remains in the purified raw material in dissolved form, which will lead to the presence of elemental sulfur in commercial products derived from oil and condensate, or to the need for additional purification, for example, by hydrotreating.

A known method of purifying oil and gas condensate from hydrogen sulfide and mercaptans by introducing a 3-30% solution of urotropine in technical formalin or in a mixture of formalin and aqueous ammonia at the rate of 0.8-3.5 moles of formaldehyde and 0.09-0.30 moles of urotropine per 1 mol of hydrogen sulfide and mercaptan sulfur (patent application RU 2004120224, IPC C10G, filed July 1, 2004). The main disadvantages of the invention are:

- the duration of the chemical process is 1-5 hours, which requires the implementation of this process in the tank with the formation of ammonia effluents;

- with a large content of mercaptans C ₁ -C ₂ (more than 400 ppm) for 1 hour at 55-70 ° C, their number can be reduced only to 150-200 ppm. Additional exposure for 2-5 hours allows you to reduce the content of C ₁ -C ₂ mercaptans by another 150-250 ppm, and this happens due to the transition of light mercaptans to heavier ones with a higher molecular weight, i.e. the total amount of light and heavy mercaptans is practically does not change.

There is also known a method of purification of oil, gas condensate and their fractions from mercaptans and hydrogen sulfide by treating the feedstock with methanol ethanolamine, dimethanol ethanolamine, methanol diethanolamine or a mixture thereof, taken in an amount of 0.3-2.0 mol per 1 mol of mercaptan and hydrogen sulfide sulfur. Methanol ethanolamine, dimethanol ethanolamine or methanol diethanolamine is used in the form of an aqueous solution previously prepared by reacting mono- or diethanolamine with an aqueous solution of formaldehyde (patent RU 2121492, IPC C10G, filed April 11, 1996, published November 10, 1998). The main disadvantage of the invention is the low degree of purification of raw materials from mercaptans at the level of 21.7-71.0%, in addition, it is necessary to implement the stage of regeneration of aqueous solutions of methanol ethanolamine, dimethanol ethanolamine or methanol diethanolamine.

There is also known a method of stabilizing gas-saturated oil, including two-stage oil separation with gas evolution and its subsequent fractionation (patent RU 2465304, IPC C10G 53/02, filed August 12, 2011, published October 27, 2012). The main disadvantage of the invention is the low clarity of the separation of gas from oil and the absence of their purification from sulfur-containing substances, since light mercaptans and hydrogen sulfide are converted into gas, and heavy mercaptans remain in stabilized oil.

Also known is the closest to the claimed invention method of stabilization and purification of hydrogen sulfide- and mercaptan-containing oil, including rectification of raw materials in two successive columns equipped with contact and drain devices, introducing steam irrigation to the bottom and liquid irrigation to the top of the columns and removing stable and purified residues from the bottom columns to obtain marketable oil by mixing them (Telyashev G.R., Telyasheva M.R., Telyashev G.G., Arslanov F.A. Oil and gas business, 2010 No. 1, http://www.ogbus.ru/autors/TelyashevGR/TelyashevGR_2pdf).). The main disadvantages of the invention are:

- in gases discharged after condensation from the separator and called concentrate of hydrogen sulfide and light mercaptans, which are further sent for purification, practically only 3% of hydrogen sulfide and less than 0.5 and 1.0%, respectively, of methyl mercaptan and ethyl mercaptan are contained, which does not allow to obtain in this method ethyl mercaptan as a commodity odorant and prevents its release from the gas stream in other ways;

- rectification in the second column is carried out in the temperature range 55-85 ° C, which does not allow it to maintain a rational temperature regime until the gasoline fractions necessary for the implementation of various secondary processes are isolated, only a portion of the gasoline solvent is withdrawn, which does not have a sufficiently wide application and injected back into oil;

- the use of a fraction of gasoline buffer separator for distillation from oil by lowering the pressure in it relative to the bottom of the first distillation column is inefficient, since the separation of products in the separator tank is carried out according to the principle of single evaporation, equivalent to one theoretical plate; this leads to the fact that the so-called concentrate of hydrogen sulfide and light mercaptans taken from the separator to the side contains 66.5% of the mass. hydrocarbons from pentane and above;

- mixing of two steam streams from the top of the first and second distillation columns due to differences in their compositions and temperatures is thermodynamically inefficient;

- the supply of the original oil as liquid irrigation to the top of the first distillation column reduces the quality of fractionation in this apparatus, since the vapors leaving the top of the first distillation column must be in equilibrium with the supplied irrigation and, therefore, not only will the vapor transfer to a certain extent lighter but also heavier hydrocarbons;

- the degree of purification of the original oil from methyl mercaptan and ethyl mercaptan does not exceed 84.2% of the mass .;

- significant heat consumption for the implementation of the process in the first distillation column.

A known installation for processing unstable gas condensate mixed with associated oil, including a condensate stabilization unit from a deethanizer column and a stabilizer column and a condensation fractionation unit from a distillation column and a stripping column, a furnace, refrigerators, heat exchangers, tanks, pumps and a piping system, connecting devices to each other, while the column-deethanizer through a system of pipelines is connected to a separator, a heat exchanger and a furnace, and the column-stabilizer through a system pipelines in the upper part is connected to an air cooler associated with a reflux capacity, and in the lower part to an oven and an air cooler, said columns being interconnected via a heat exchanger, said condensate fractionation unit further comprises a stripping column connected to a distillation column, stripping the column through a pipeline system is connected to the bottom of the distillation column through a heat exchanger, air cooler, tank and pump, in the upper part of the distillation constant prices column by the piping system is connected to an air condenser and a capacity (patent RU 2477301, IPC B01D, C10G, pending 08.12.2011, published 10.03.2013). The main disadvantages of the invention are:

- the inoperability of the deethanizer column, considered as a distillation column, but having neither the scheme nor the description of the irrigation system, without which significant losses of light hydrocarbons coming from the top of the deethanizer column and irrationally used as fuel are unavoidable;

- there are no conclusions of rectification products from the bottom of the column-deethanizer and column-stabilizer;

- products leaving the stabilizer column and then entering the furnace for heating in front of the distillation column to 300 ° C are energetically irrationally cooled along the way in an air cooler to 40 ° C;

- the distillation column does not have a distant portion, which is why in the column the clarity of separation and the low quality of the resulting kerosene fraction are reduced;

- the installation does not provide for demercaptanization of stabilized gas condensate;

- low quality of motor fuel (fractions nk-160 ° C) due to the insufficient number of contact plates (20 plates) in the distillation column.

The closest to the claimed invention is the installation of stabilization and purification of hydrogen sulfide and mercaptan-containing oil, including two distillation columns equipped with contact and drain devices, heat exchangers, an oven, a buffer tank-separator, a refrigerator, a gas separator, a boiler, connected by a piping system (G. Telyashev ., Telyasheva M.R., Telyashev G.G., Arslanov F.A. Oil and Gas Business, 2010, No. 1, http://www.ogbus.ru/autors/TelyashevGR/TelyashevGR_2pdf). The main disadvantages of the invention are:

- the joint implementation of cooling and separation of the distillates of both distillation columns having different compositions and temperatures complicates the selection of the operating mode of the refrigerator;

- the supply of vapors from the buffer tank to the gas separator is equivalent to simply dumping the vapor from it into the gas network bypassing the gas separator, and the technological scheme of the installation becomes ineffective, since the meaning of using a second distillation column is lost;

- the use in the first distillation column of contact plates overloaded with the liquid phase and underloaded from the vapor phase with the minimum dimensions of the perforated elements (for example, small-louvered type) with double depth drain devices is irrational, since contact systems with double depth drain devices are equivalent to contact systems with drain devices unit depth, but with doubling the cross section of the column in the vapor phase, which under conditions of an already low steam load reduces the mass transfer hydrochloric efficiency of contact devices;

- combining the flows of stable oil after the first distillation column and part of the gasoline-solvent after the second distillation column (previously extracted from oil).

The objective of the claimed invention is to develop a method of weathering and stabilization of unstable gas condensate mixed with oil with absorption extraction of mercaptans, during which, along with obtaining a stable mixture of oil and gas condensate, it is purified from methyl mercaptan and the necessary assortment of hydrocarbon fractions is needed for subsequent extraction of odorants - ethyl mercaptan of isomeric and normal propyl mercaptans and isomeric and normal butyl mercaptans or a mixture of mercaptans, as well as development Fitting stabilize unstable condensate in admixture with the oil removing mercaptans from the absorption that ensures implementation of the method.

To solve this problem, we propose a method of weathering and stabilization of unstable gas condensate mixed with oil with absorption extraction of mercaptans, including the separation of raw materials in two successive columns equipped with contact and drain devices, the introduction of steam irrigation to the bottom and liquid irrigation to the top of the columns and the output of stable and purified residues from the bottom of the columns, the initial mixture of unstable gas condensate and oil is subjected to weathering and fed to the first distillation stabilizer column , a stable mixture of gas condensate with oil from the bottom of the first distillation stabilizer distillation column is fed into the second distillation column, from the top of which hydrocarbon fractions containing ethyl mercaptan, isomeric and normal propyl mercaptans and isomeric and normal butyl mercaptans, isomeric mixtures and corresponding mer a heavy residue is removed from the bottom of the second distillation column, part of which is fed to the top of the third absorption column as an absorbent for the residual heavy mercaptans from the weathering gases discharged from the top of the separators and the stabilization gas discharged from the top of the first stabilization column supplied by combined or separate streams to the third absorption column, from the bottom of which the absorbent saturated with heavy mercaptans is fed to the middle part of the first stabilization the columns.

The weathering of the initial mixture of unstable gas condensate and oil by reducing pressure will allow the primary coarse stabilization of raw materials during a single evaporation, corresponding to one theoretical plate, practically without significant energy consumption, transferring the bulk of hydrogen sulfide, methane, methyl mercaptan and a small part of heavier mercaptans and hydrocarbons into the gas phase .

After that, the first stabilization column solves the problem of clear fractionation during stabilization of the feedstock while removing methyl mercaptan, which is not used as an odorant, from it, and the second distillation column serves to isolate hydrocarbon fractions containing specific types of mercaptans used as odorants for subsequent isolation. Mercaptans with a boiling point of 35.0 ° C (ethyl mercaptan), 52.5 ° C (isopropyl mercaptan), 67.6 ° C (normal propyl mercaptan), 64.2-119 ° C (isomeric and normal butyl mercaptan) can be extracted taking into account potential clarity of fractionation from hydrocarbon fractions respectively nk-75 ° C, 65-75 ° C, 75-130 ° C (Overview. Gas industry. Series “Preparation and processing of gases and gas condensate. Issue 8. Extraction of low boiling mercaptans from gas processing products factories and ways of using them. Moscow. 1986, p.13), and mixtures of The corresponding mercaptans can be extracted from hydrocarbon fractions respectively NK-65 ° C, NK-75 ° C, NK-130 ° C.

In this regard, it is advisable to separate the hydrocarbon fraction nk-65 ° C when preparing raw materials for the extraction of ethyl mercaptan from the top of the second distillation column; to separate the hydrocarbon fraction nk-75 ° from the top of the second distillation column to prepare the raw materials for the extraction of ethyl mercaptan from the top of the second distillation column C, in the preparation of raw materials for the extraction of ethyl mercaptan, isomeric and normal propyl mercaptans, isomeric and normal butyl mercaptans from the top of the second distillation column, isolate the hydrocarbon fraction nk-130 ° C.

The third absorption column allows the additional isolation of ethyl mercaptan and heavier mercaptans from weathering gases and stabilization gas, using heavy residues of the second distillation column as absorbent. The optimal consumption of absorbent can be calculated by the minimum value of the parameter, equal to the ratio of the increase in the consumption of absorbent to the increase in absorbed ethyl mercaptan, which corresponds to the maximum efficiency of the use of absorbent in the third absorption column.

It is also advisable to weather the initial mixture of unstable gas condensate and oil in several stages with a successive decrease in pressure and regenerative heating of the weathered raw material, which will reduce energy costs in the first stabilization column by reducing the column capacity for the emitted stabilization gas.

It is economically feasible to use recuperative heat exchange with stable and purified residues from the bottom of these columns when heating the feed streams of the first stabilization column and the second distillation column, which allows to optimize energy costs for the implementation of the proposed method as a whole.

Due to the fact that the weathering gases discharged from the top of the separators and the stabilization gas discharged from the top of the first stabilization column will have a different composition, and the weathering gases are more lightweight compared to the stabilization gas, it is advisable to feed them into the third absorption column separately such contact devices in which the compositions of the gas phases are closest to the compositions of the weathering gases and the stabilization gas.

To solve this problem, it is also proposed to install an unstable gas condensate stabilization in a mixture with oil with absorption extraction of mercaptans, including two columns equipped with contact and drain devices, heat exchangers, furnaces, refrigerators, a gas separator connected by a piping system, which additionally contains a weathering system and a third absorption column , the first stabilization column is connected to the second distillation column with a stable residue supply line, the second distillation the first column is connected to the third absorption column by a heavy residue supply line, the second distillation column has a steam irrigation system in the form of a circulation circuit connecting the bottom of the column, a residue transfer pump and a furnace for creating a hot stream, the bottom circulation circuit of the second distillation column after the pump is connected by a pipeline with a recuperative heat exchanger heating the raw materials of this column.

It is advisable to mix the product withdrawn from the bottom of the separators with a saturated absorbent and feed it into the first stabilization column independently of each other.

It is also advisable that the third absorption column was equipped in the lower part with at least one fitting for introducing weathering and stabilization gases or several fittings located at different heights of the column for separate supply of weathering and stabilization gases.

The invention is illustrated in the drawing, where figure 1 shows a diagram of the proposed installation for stabilization of unstable gas condensate mixed with oil with absorption extraction of mercaptans according to the proposed method of stabilization of unstable gas condensate mixed with oil with absorption recovery of mercaptans.

The installation diagram for stabilizing unstable gas condensate mixed with oil with absorption extraction of mercaptans contains the following positions:

100 - filter

102, 104, 106 - separator,

101, 103, 105, 107 - recuperative heat exchanger,

108 - the first stabilization column,

109, 115, 117 - refrigerator,

110 - gas separator,

111, 112, 119, 120, 123 - pump,

113, 121 - oven,

116 - the second distillation column,

118 - irrigation capacity,

122 - third absorption column,

1-44 - pipelines.

The inventive method of stabilizing an unstable gas condensate mixed with oil with absorption extraction of mercaptans is as follows. Unstable gas condensate mixed with oil with a pressure of 17-22 kgf / cm ^{2 is} pre-cleaned in filters, then heated in a heat exchanger and enters the degassing system, which is produced in three-phase separators in three stages by reducing the pressure to 15-16 kgf / cm ² at the first stage, 13-14 kgf / cm ² - at the second, with additional heating to 95 ° C and up to 12 kgf / cm ² at the third with heating to 110 ° C. The formed weathering gases are combined and sent for absorption, and the hydrocarbon condensate is sent for dehydration and desalination (ELOU block) in two stages. Next, the dehydrated and desalted unstable gas condensate mixed with oil is heated in a recuperative heat exchanger 107 to a temperature of no more than 175 ° C and is sent to stabilization in the first stabilization column 108 for a 20 theoretical plate. This column has 30 theoretical plates. Heat is supplied to the first stabilization column 108 due to the bottoms product circulating with the pump 112 through the coil of the furnace 113. Stable condensate from the first stabilization column with a temperature of no higher than 224 ° C is sent to the heat exchanger 107, then it is divided into two streams, one of which is removed from the installation, and the remaining part of the stable condensate is heated in the heat exchanger 114 and enters the second distillation column 116. The vapor-gas mixture from the first stabilization column 108 with a temperature of not more than 70 ° C is cooled It is stored in a refrigerator 117 and fed to a gas separator 110, from where liquid hydrocarbons are pumped to a column 108 for irrigation by a pump 111, and stabilization gas is sent for absorption to a third absorption column 122.

Stable condensate after heat exchanger 116 enters the 13th plate of the second distillation column, from the top of which the vapor phase is cooled in the refrigerator 117, then to the irrigation tank 118, from where part of the fraction is NK-65 ° C, NK-75 ° C or NK-130 ° C is returned to the column as irrigation, and the remainder is discharged from the installation. The bottom residue from the bottom of the second distillation column 116 is fed to the pump 120, after which part of it through the coil of the furnace 121 is returned to the second distillation column 116, and the rest is cooled in the heat exchanger 114, 115 to a temperature of 40 ° C, then the bottom residue of the second distillation column 116 is divided into two parts, one part is discharged from the installation, and the other part is sent to the third absorption column 122 as an absorbent.

Weathering gases and stabilization gas are supplied either to various theoretical plates, or to one common theoretical plate to the third absorption column 122, in which light hydrocarbons of C ₅ and higher, as well as ethyl and propyl mercaptans are absorbed. Hydrocarbon gas is discharged from the top of column 122, in which there are no mercaptans C ₂ or higher, and from the bottom, saturated absorbent is received by pump 123, after which it is mixed with unstable gas condensate leaving the ELOU unit and sent to stabilization.

Installation stabilization of unstable gas condensate mixed with oil with absorption extraction of mercaptans is implemented according to the invention as follows.

The raw material through pipeline 1 enters the filter 100, after which through the pipeline 2 to the recuperative heat exchanger 101, then the cleaned and heated raw materials through the pipeline 3 are sent to the first stage to the separator 102, from where the weathering gases are removed from the top through the pipeline 5, and from the bottom - to pipeline 4, the flow enters heat exchanger 103, after which a second degassing stage is carried out in the separator 104, from the top of which weathering gases are discharged through pipeline 7, and from below the unstable gas condensate stream mixed with oil 8 is heated in rivers heat exchanger 105 and enter the third stage of degassing in the separator 106, from the top of which the weathering gases are discharged through the pipeline 10, and from the bottom through the pipeline 12 the unstable gas condensate mixed with oil are sent for electric dewatering and electric desalination to the ELOU unit, from where water is discharged through the pipe 13, and the pipeline 14 dehydrated and desalted raw materials. The saturated absorbent from the third absorption column 122 is combined through a pipeline 41 with a stream of dehydrated and desalted condensate and fed through a pipe 15 to a recuperative heat exchanger 107, where it is heated by the heat of the bottom residue of the first stabilization column 108, then through a pipe 16, the heated stabilization feed is fed to the first stabilization column 108. In addition, the saturated absorbent can be fed directly to the first stabilization column 108 (not shown in FIG. 1), from the top of which pairs are piped 17 enter the refrigerator 109, then through the pipe 18 to the gas separator 110, from which stabilization gas is discharged through the pipe 19, and condensed hydrocarbon condensate is passed through the pipe 20 to a pump 111, after which it returns to the first stabilization tower 108 through the pipe 21 irrigation. Also, the circuit provides for the conclusion from the installation of condensed hydrocarbon condensate (not shown in Fig. 1). Heat is supplied to the bottom of the first stabilization column 108 by circulating a hot stream through the furnace 113. This is achieved by the fact that stable condensate is removed from the bottom of the first distillation column 108 through a pipe 22, then it is received at the pump 112, and then part of the stable condensate is transferred to the furnace 113 and is fed to the bottom of the first stabilization column 108. The remaining part of the stable condensate discharged through the pipe 25 from the bottom of the first stabilization column 108 as a still product is cooled in a regenerative heat exchanger 107, then it is divided into two flows, one of which is fed through a pipe 26 to a heat recovery heat exchanger 114 and fed through a pipe 27 to a second distillation column 116 for separation to obtain a fraction of NK-65 ° C, NK-75 ° C, NK -130 ° C, and the second bottoms stream of the second distillation column 116 is discharged from the installation via the pipeline 42. From the top of the second distillation column 116, hydrocarbon vapors are taken off through the pipe 28 for cooling to the refrigerator 117, after which the stream flows through the pipeline into a container be irrigation 118, whence the fraction via line 30, then a part of it is removed through conduit 38 from a facility and another part is supplied to the pump suction 119, after which via line 31 is returned as reflux. Heat is supplied to the bottom of the second distillation column 116 due to the circulation of the hot stream through the furnace 121. This is achieved by the fact that the bottom residue is removed from the bottom of the second distillation column 116 through the pipe 32, then it is received by the pump 120, then part of it through the pipe 33 enters the furnace 121 and through a pipe 34 is fed to the lower part of the second distillation column 116. The remaining part of the bottom residue discharged through the pipe 35 from the bottom of the second distillation column 116 as the bottom product is cooled in a recuperative heat exchanger 114 and further through the pipe 36 is additionally cooled in the refrigerator 115 and through the pipe 37 is removed from the installation. The nk-75 ° C fraction (or the nk-65 ° C or nk-130 ° C fraction) withdrawn from the top of the second distillation column 116 is drawn into the bottoms of the first stabilization column 108 and the second distillation column 116, respectively, through pipelines 44 and 43.

The weathering gases after the separators 102, 104 and 106 are combined and sent through a pipe 11 for absorption to the third absorption column 122. The stabilization gas through a pipe 19 is also fed to the absorption to the third absorption column 122. The gases are introduced into the third absorption column 122 on various plates, it is also possible to serve on one common plate (not shown in Fig. 1). From the top of the third absorption column 122, hydrocarbon gas is discharged through a pipeline 39, in which there are no mercaptans C ₂ and above, and from the bottom, a saturated absorbent is discharged through a pipe 40 and is received by a pump 123, after which it is mixed with an unstable gas condensate leaving the ELOU unit and sent to stabilization.

Example 1. Mathematical modeling of the U-730 installation at the Orenburg gas processing plant with a capacity of up to 4.16 million tons / year was carried out using raw materials designed to stabilize unstable gas condensate mixed with oil, which was equipped with the inventive method of absorption extraction of mercaptans. This installation further includes a third absorption column containing 10 theoretical plates. The consumption of absorbent material (75 ° C-kk) is 25 t / h, stabilization and weathering gases are 26 and 29 t / h, respectively. Table 1 presents the calculation results for different input of raw materials into the third absorption column. According to the data presented, the introduction of stabilization gas and weathering gas on different plates (stabilization gas on the sixth plate from the bottom, weathering gases on the first plate from the bottom) is more profitable than the general input of raw materials, this is confirmed by a decrease in the concentration of methyl mercaptan in a saturated absorbent: with a common input of raw materials in the third absorption column, the content of methyl mercaptan in the saturated absorbent is 2 times higher (50 kg / h versus 25 kg / h) than with the separate supply of stabilization and weathering gases. Separate gas entry into the 6 theoretical plate from the bottom allows the supply of weathering gases to the third absorption column in an area in which the concentration of recovered ethyl mercaptan is lower than the stabilization gas, which helps to extract the target product ethyl mercaptan with an absorbent.

Example 2. Mathematical modeling of the same installation with the determination of the optimal consumption of absorbent. The operating parameters of the third absorption column are the same and Table 2 shows the calculation results for the separate introduction of stabilization and weathering gas at different absorbent consumption in the range of 10-50 t / h. From the data of table 2 it follows that an increase in the consumption of absorbent causes an increase in the selection of ethyl mercaptan, however, the efficiency of the absorption process of ethyl mercaptan decreases with high consumption of absorbent. The figure 2 presents the differential dependence of the additional consumption of absorbent to the additional selection of ethyl mercaptan from the consumption of absorbent; the most optimal flow rate of the absorbent supplied to the third absorption column is 15-20 t / h.

Example 3. Mathematical modeling of the same installation was performed with the selection of the optimal temperature of the absorption process. The parameters of the third absorption column are the same. The figure 3 presents a graph of the influence of the temperature of the absorption process on the amount of absorbed mercaptans, namely methyl mercaptan and ethyl mercaptan. The most rational temperature range of the absorption process is from 35 to 40 ° C.

Example 4. Mathematical modeling of the same installation was performed depending on the composition of the absorbent. The use of bottoms of the second distillation column as absorbents after separation of fractions nk-65 ° C or nk-130 ° C is considered. The parameters of the third absorption column are the same. Table 3 shows the data for the extraction of mercaptans in the third absorption distillation column with separate input of raw materials along the height of the column. When using fractions of 65 ° C-kk, 130 ° C-kk, as well as 75 ° C-kk (table 2), the absorption of ethyl mercaptan is 152, 145, and 151 kg / h, respectively, which allows us to consider it most acceptable to use as absorbent light bottoms. However, the heavy bottoms residue after the selection of the NK-130 ° C fraction is also acceptable for the extraction of ethyl mercaptan while varying the technological mode of operation of the third absorption column.

The results of mathematical modeling and analysis of the method and installation for stabilizing unstable gas condensate mixed with oil with absorption extraction of mercaptans in the presented examples shows that the claimed invention allows, along with the production of a stable mixture of oil and gas condensate, to purify its methyl mercaptan and to develop a wide range of hydrocarbon fractions necessary for subsequent extraction of odorants.

Table 1 Name of parameters unit of measurement Weathering gases Stabilization gases Total absorption gas Absorbent General input of raw materials on one plate Separate input of raw materials into two plates Purified gas Saturated Absorbent Purified gas Saturated Absorbent Stream number eleven 19 - 37 39 41 39 41 Temperature ° C 38 40 Pressure kg / cm ² 10 Mass flow kg / h 28780 25882 54662 25,000 39521 40157 44491 35170 Mass content of mercaptans % of the mass. - CH ₄ S 0.06 0.28 0.17 - 0.10 0.13 0.15 0,07 - C ₂ H ₆ S 0.27 0.38 0.32 - 0.06 0.38 0.06 0.43 - ∑C ₃ H ₈ S 0.09 0,07 0.08 - - 0.12 - 0.13 - ∑C ₄ H ₁₀ S 0.05 - 0,03 0.18 0.01 0.14 0.18 0.16 Mass content of mercaptans kg / h - CH ₄ S 19 73 92 - 41 51 67 25 - C ₂ H ₆ S 79 98 176 - 25 152 25 151 - ∑C ₃ H ₈ S 26 19 45 - - 46 - 46 -∑C ₄ H ₁₀ S fifteen - fifteen 5 46 56 46 56

table 2 Name of parameters unit of measurement Absorbent consumption, t / h 10 fifteen twenty 25 thirty 35 fifty Purified gas Saturated Absorbent Purified gas Saturated Absorbent Purified gas Saturated Absorbent Purified gas Saturated Absorbent Purified gas Saturated Absorbent Purified gas Saturated Absorbent Purified gas Saturated Absorbent Mass flow kg / h 52008 12648 50194 19516 47198 27463 44491 35170 42193 42469 40227 49435 35741 68921 Mass content of mercaptans % of the mass. - CH ₄ S 0.17 0.04 0.17 0.05 0.16 0.06 0.15 0,07 0.14 0.08 0.12 0.09 0,07 0.1 - C ₂ H ₆ S 0.27 0.2 0.17 0.46 0.09 0.48 0.06 0.43 0.04 0.38 0.02 0.34 0.01 0.2 - ∑C ₃ H ₈ S - 0.36 - 0.24 - 0.17 - 0.13 - 0.10 - 0.10 - 0,07 - ∑C ₄ H ₁₀ S 0.01 0.23 0.01 0.19 0.01 0.17 0.18 0.16 0.01 0.15 0.01 0.15 0.01 0.15 Mass content of mercaptans kg / h - CH ₄ S 87 5 83 9 76 16 67 25 58 34 48 44 24 68 - C ₂ H ₆ S 139 37 86 89 43 133 25 151 16 161 10 166 3 173 - ∑C ₃ H ₈ S - 27 - 46 - 46 - 46 - 46 - 46 - 47 - ∑C ₄ H ₁₀ S 5 29th 5 38 5 47 46 56 5 65 5 74 5 102

Table 3 Name of parameters unit of measurement VAT residue after fraction NK-65 ° C VAT residue after fraction NK-130 ° C Purified gas Saturated Absorbent Purified gas Saturated Absorbent Mass flow kg / h 44,460 35202 45741 33919 Mass content of mercaptans kg / h - CH ₄ S 67 25 68 24 - C ₂ H ₆ S 25 152 31 145 - ∑C ₃ H ₈ S - 46 - 45 - ∑C ₄ H ₁₀ S 5 56 - fifteen

Claims (12)

1. The method of weathering and stabilization of unstable gas condensate mixed with oil with absorption extraction of mercaptans, including the separation of raw materials in two successive columns equipped with contact and drain devices, the introduction of steam irrigation to the bottom and liquid irrigation to the top of the columns and the withdrawal of stable and purified residues from the bottom of the columns, characterized in that the initial mixture of unstable gas condensate and oil is subjected to weathering and fed into the first distillation column stabilizer, a stable mixture of gas the condensate with oil from the bottom of the first distillation stabilizer column is fed to the second distillation column, from the top of which hydrocarbon fractions containing ethyl mercaptans, isomeric and normal propyl mercaptans and isomeric and normal butyl mercaptans or mixtures of the second mercaptans, which are recovered as odorants, are removed a distillation column discharges a heavy residue, part of which is fed to the top of the third absorption column as an absorbent to absorb residual heavy x weathering mercaptans from gases discharged from the top separator, and stabilizing the gas withdrawn from the top of the first column of the stabilization supplied to a third absorption tower from the bottom of which a saturated heavy mercaptans absorbent is supplied as the average recirculate a portion of the first stabilization column. 2. The method of weathering and stabilization of unstable gas condensate in a mixture with oil with absorption extraction of mercaptans according to claim 1, characterized in that the optimal absorbent consumption is calculated by the minimum value of the parameter equal to the ratio of the increase in absorbent consumption to the increase in absorbed ethyl mercaptan. 3. The method of weathering and stabilization of unstable gas condensate in a mixture with oil with absorption extraction of mercaptans according to claim 1, characterized in that when preparing raw materials for the extraction of ethyl mercaptan from the top of the distillation column, the HC-65 ° C hydrocarbon fraction is isolated. 4. The method of weathering and stabilization of unstable gas condensate mixed with oil with absorption extraction of mercaptans according to claim 1, characterized in that when preparing raw materials for the extraction of a mixture of ethyl mercaptan, isomeric and normal propyl mercaptans from the top of the distillation column, the HC-75 ° C hydrocarbon fraction is isolated. 5. The method of weathering and stabilization of unstable gas condensate mixed with oil with absorption extraction of mercaptans according to claim 1, characterized in that when preparing raw materials for the extraction of ethyl mercaptan, isomeric and normal propyl mercaptans, isomeric and normal butyl mercaptans from the top of the distillation column, the hydrocarbon is isolated 130 ° C. 6. The method of weathering and stabilization of unstable gas condensate in a mixture with oil with absorption extraction of mercaptans according to claim 1, characterized in that the weathering of the initial mixture of unstable gas condensate and oil is performed in several stages with a successive decrease in pressure and regenerative heating of the weathered raw material. 7. The method of weathering and stabilization of unstable gas condensate mixed with oil with absorption extraction of mercaptans according to claim 1, characterized in that when heating the feed streams of the first stabilization column and the second distillation column, regenerative heat exchange with stable and purified residues from the bottom of these columns is used. 8. The method of weathering and stabilization of an unstable gas condensate mixed with oil with absorption extraction of mercaptans according to claim 1, characterized in that the weathering gases discharged from the top of the separators and the stabilization gas discharged from the top of the first stabilization column are combined into a third absorption column or separately. 9. The method of weathering and stabilization of an unstable gas condensate mixed with oil with absorption extraction of mercaptans according to claim 8, characterized in that the weathering gases discharged from the top of the separators and the stabilization gas discharged from the top of the first stabilization column are supplied to the third absorption column separately to such contact devices in which the compositions of the gas phases are closest to the compositions of the weathering gases and stabilization gases. 10. Installation of weathering and stabilization of unstable gas condensate mixed with oil with absorption extraction of mercaptans, including two columns equipped with contact and drain devices, heat exchangers, furnaces, refrigerators, a gas separator connected by a piping system, characterized in that it additionally contains a weathering system and a third absorption column, the first stabilization column is connected to the second distillation column by a stable residue supply line, the second distillation column is bound on the third absorption column with a heavy residue supply line, the second distillation column has a steam irrigation system in the form of a circulation loop connecting the bottom of the column, a residue transfer pump and a furnace for creating a hot stream, the circulation circuit of the bottom of the second distillation column after the pump is connected to a regenerative pipeline a heat exchanger heating the raw materials of this column. 11. The installation of weathering and stabilization of unstable gas condensate mixed with oil with absorption extraction of mercaptans according to claim 10, characterized in that the product discharged from the bottom of the separators is mixed with a saturated absorbent and fed to the first stabilization column independently of each other. 12. Installation of weathering and stabilization of unstable gas condensate in a mixture with oil with absorption extraction of mercaptans according to claim 10, characterized in that the third absorption column has at least one fitting for introducing weathering and stabilization gases or several fittings, located at different column heights, for separate supply of weathering gases and stabilization gas.

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