RU2115684C1 - Method for production of hydrocarbon propellents - Google Patents

Abstract

FIELD: production of hydrocarbon propellents. SUBSTANCE: hydrocarbon raw materials are affected by rectification, thus hydrocarbon mixture having predetermined composition is prepared. Gage pressure of saturated steam of said mixture corresponds to gage pressure of saturated steams of hydrocarbon propellents. Then thus isolated hydrocarbon mixture is affected by preliminary purification together with its deodorization. The process is carried out on activated coal and is followed by drying, purification and deodorization which takes place on consequently disposed layers of NaA, CaA and NaX zeolites. Zeolites are regenerated with the help of nitrogen or with the help of dried and purified hydrocarbon gas. EFFECT: improved efficiency of the method, improved quality of product. 5 cl, 1 dwg

Description

 The invention relates to a technology for the production of environmentally friendly hydrocarbon gases - propellants and can be used in the gas, oil, oil refining and petrochemical industries, as well as in household chemicals, medicine and perfumery.

 The closest in technical essence and the achieved result to the proposed one is the method for producing hydrocarbon propellants described in the article "Current status and prospects for the use of hydrocarbon propellants in capitalist countries" (overview information, series: "Chemical Industry Abroad", issue 1, p. 20 - 43).

 The essence of the method lies in the fact that the raw materials used are gases from gas refineries, oil refineries and petrochemical enterprises (fractionation, cracking, reforming gases, isomerization products). A fraction of liquefied hydrocarbons from propane to pentane, which is the feedstock for producing hydrocarbon propellants, is isolated from the source gas. After deethanization, the hydrocarbon mixture is subjected to low-temperature fractionation in order to isolate propane, n-butane, isobutane. The resulting components are thoroughly cleaned of traces of the catalyst, unsaturated and sulfur compounds. For example, the propane fraction after treatment with acid is washed with an alkaline solution to get rid of traces of acid, then subjected to stepwise rectification to remove the remaining odorous substances and dry for dehydration. Then the purified and dried hydrocarbons are mixed to prepare mixtures with a given saturated steam pressure.

The disadvantages of this method are:
high operating costs;
the resulting propellants have a slight specific odor;
acid and alkaline wastes are generated during the manufacturing process.

 The objective of the proposed method is to create an environmentally friendly technology for the production of hydrocarbon propellants, which will allow to obtain high quality products with a low content of sulfur compounds, expand the range of raw materials used and reduce operating costs for the process.

 The problem is achieved in that in a method for producing hydrocarbon propellants, including rectification of hydrocarbon feedstock, purification, deodorization and drying, a mixture of hydrocarbons of a given composition with an excess pressure of saturated vapors corresponding to an excess pressure of saturated vapors of hydrocarbon propellants is isolated and subjected to preliminary cleaning and deodorization on activated carbon, and drying is carried out on synthetic zeolites.

 In addition, after preliminary cleaning and deodorization, hydrocarbon raw materials are dried, purified and deodorized on synthetic zeolites, followed by zeolite regeneration.

 Moreover, drying, cleaning and deodorization is carried out by passing a mixture of hydrocarbons through sequentially placed layers of zeolites NaA, CaA and NaX. The regeneration of zeolites is carried out with nitrogen or dried and purified hydrocarbon gas.

Distinctive features from the closest analogue are:
the allocation in the process of distillation of a mixture of hydrocarbons of a given composition with an excess pressure of saturated vapors corresponding to an excess pressure of saturated vapors of hydrocarbon propellants;
preliminary purification of the mixture extracted after rectification of hydrocarbons on activated carbon;
drying on synthetic zeolites;
conducting, after preliminary cleaning and deodorization, drying, cleaning and deodorization on synthetic zeolites with subsequent regeneration of zeolites;
drying, cleaning and deodorizing by passing a mixture of hydrocarbons through sequentially placed layers of zeolites NaA, CaA and NaX;
the use of nitrogen recovery gas or dried and purified hydrocarbon gas as a gas.

As a result of rectification of hydrocarbon feedstocks, light hydrocarbons are first separated, and heavier C _{3 + b} hydrocarbons are sent to further rectification, where, under the given mode, hydrocarbons are obtained not as individual products, but as a mixture of hydrocarbons with an excess pressure of saturated vapors corresponding to an excess pressure of saturated vapors of hydrocarbon propellants.

Thus, as a feedstock for the production of hydrocarbon propellants, any hydrocarbon mixture containing C _{3 + b} , for example NGL, can be used.

 Preliminary cleaning and deodorization of the hydrocarbon mixture extracted after rectification with activated carbon can prevent rapid deactivation and extend the life of synthetic zeolites, as well as improve the quality of the resulting product by absorbing tar, light sulfur compounds, RSR, COS, and unsaturated hydrocarbons with activated carbon.

Deep drying and fine purification of the hydrocarbon mixture is carried out by passing the latter through layers of zeolites NaA, CaA and NaX. In this case, the NaA zeolite layer is the first along the hydrocarbon mixture, then the CaA zeolite layer and the NaX zeolite layer. Deep drying of the hydrocarbon mixture is achieved on NaA zeolite, CaA zeolite absorbs light sulfur compounds such as hydrogen sulfide, methyl mercaptan and ethyl mercaptan, and all mercaptans and sulfides are removed on NaX zeolite. Moreover, the ratio of the layers is calculated in each case, depending on the composition and requirements of the finished product, in order to maximize the capacity of each layer of the sorbent for the extracted component. The use of just such a combination of NaA, CaA, and NaX layers allows a new quality of the combined layer to manifest itself - to limit the adsorption of C _{3 + B} hydrocarbons to the maximum, and this leads to an increase in the dynamic capacity of zeolites for the extracted component, an increase in the selectivity of hydrocarbon mixture purification, and an increase in the service life of zeolites.

 The use of technical nitrogen as a regeneration gas or of purified and dried hydrocarbon gas reduces operating costs, since the regeneration gas necessary for technological purging of equipment and thermogas regeneration of zeolites is prepared directly at the installation for producing propellants.

 The proposed method is carried out on the installation, the technological scheme of which is shown in the drawing.

 From liquefied gases in a distillation unit, including a heat and mass transfer apparatus (1) and a unit for producing a propellant composition (2), a propane-butane-isobutane mixture of a given composition with an excess pressure of saturated vapors corresponding to an excess pressure of saturated vapors of hydrocarbon propellants is obtained.

 The resulting mixture is fed into alternately working carbon adsorbers (3, 4) filled with activated carbon. Having passed a layer of activated carbon from the bottom up, the mixture is purified from unsaturated compounds, asphalt-resinous compounds and partially from sulfur compounds. From coal adsorbers (3, 4), the hydrocarbon mixture is fed through the filter (5) from bottom to top into adsorbers (6, 7, 8), layer-by-layer filled with synthetic zeolites of the brands NaA, CaA, NaX. This combination of zeolite layers provides deep drying, fine purification from sulfur compounds and deodorization of the hydrocarbon mixture. The purified and dried hydrocarbon mixture with a mass content of sulfur compounds of 0.00001% leaves adsorbers (6, 7, 8) and is discharged through filters (9, 10) as a finished product (11). The regeneration of activated carbon in adsorbers (3, 4) is carried out in a known manner, for example, with water vapor. The regeneration of zeolites in adsorbers (6, 7, 8) is carried out by gas that has passed through the preparation unit (12). As the gas of regeneration and cooling using technical nitrogen or dried and purified hydrocarbon gas. Adsorbers (6, 7, 8) work in such a way that at the stage of adsorption, regeneration and cooling there is one apparatus.

The obtained hydrocarbon propellants in their physicochemical parameters comply with the requirements of TU 39-892-93:
Saturated vapor overpressure, MPa - 0.33 - 0.4
Mass fraction of components,%:
Ethane, not more than - 0.5
The amount of propane, butane, isobutane, not less than 99.0
Pentanes, no more - 0,5
Unsaturated hydrocarbons, not more than 0.02
Sulfur compounds, not more than - 0.0005
Non-volatile substances, not more than 0.001
Water, not more than 0.01.

Example 1. To obtain the hydrocarbon propellants necessary for aerosol packaging of the company's products, an overpressure of 0.33 - 0.36 MPa and the following composition, mass fraction of components,% are set:
Propane, butane, isobutane, not less than 99.0
Pentanes, no more - 0,3
Unsaturated hydrocarbons - None
Mass fraction of sulfur compounds, not more than 0.00001
Mass fraction of non-volatile substances, no more than 0.00002
Mass fraction of water, no more - 0,0002.

 The need to choose the composition of the propellants, as well as the overpressure of saturated vapors, is determined by the specifics of the preparation and conditions of use of a wide range of products manufactured in aerosol containers (perfumes, cosmetics, household chemicals, medicine, varnishes, paints, etc.).

Hydrocarbon gases of the following composition (mass content,%) are sent to the heat and mass transfer apparatus (1) for preliminary preparation of the raw materials: mass methane - traces; ethane 3.70; propane 33.0; propylene 0.7; isobutane 16.70; n-butane 33.60; isopentane 6.50; n-pentane 5.8; the water content of 0.22 g / m ³ ; hydrogen sulfide 0.0044 g / m ³ ; mercaptans 0.0015 g / m ³ ; asphalt-resinous substances 4 mg / 100 ml. At a top temperature of the apparatus at a level of 41 - 42 ^o C and a pressure of 2.1 MPa, light components are removed (mass content,%): methane - traces; ethane 16.2; propane 72.5; propylene 0.7; isobutane 6.2; n-butane 4.8; ∑ pentanes 0.05 from raw materials. The raw material thus prepared from the bottom of the heat and mass transfer apparatus (1) enters the unit for producing the propellant composition (2), where at a top temperature of 58.8 ^° C and a pressure of 0.9 MPa a hydrocarbon mixture of the following composition is obtained (mass content,%): ethane 0 , 49; propane - 27.51; propylene 0.3; isobutane 23.22; n-butane 47.92; the amount of pentanes 0.3; as well as water 0.20 g / m ³ ; hydrogen sulfide 0.0040 g / m ³ ; ethyl mercaptan 0.001 g / m ³ ; butyl mercaptan 0.0004 g / m ³ ; asphalt-resinous 3 mg / 100 ml. The saturated vapor pressure is 0.35 MPa, which corresponds to TU 39-92-93 per hydrocarbon propellant.

 The resulting hydrocarbon mixture enters one of the adsorbers (3, 4), where activated carbon of the AG-2 brand completely removes unsaturated hydrocarbons, asphalt-resinous substances and partially sulfur compounds.

 Next, the hydrocarbon mixture is purified on the filter (5) from the smallest particles of activated carbon and sent to one of the adsorbers (6, 7, 8), filled with synthetic zeolites NaA, CaA, NaX. The ratio of CaA: NaX layers is 2: 1.

 Deep drying and fine purification of the hydrocarbon mixture is carried out according to the three adsorber scheme, each of which works sequentially in the mode of adsorption, regeneration, cooling.

The hydrocarbon mixture in a uniform stream at a speed of 0.0012 m / s at a pressure of 0.85 MPa and a temperature of 45 ^o C is fed into the adsorber (6). At this time, the adsorber (7) is in the regeneration mode, and the adsorber (8) is in the cooling mode.

Having passed successively layers of synthetic zeolites NaA, CaA and NaX, the hydrocarbon mixture is dried and purified to a residual water content of 0.0005 g / m ³ and sulfur compounds 0.000053 g / m ³ (0.00001 wt.%).

 The obtained hydrocarbon propellant is cleaned of zeolite dust on filters (9, 10) and sent (11) to the finished product warehouse. According to its physical and chemical parameters, the obtained propellant corresponds to TU 39-892-93.

 With an increase in the mass content of sulfur compounds of more than 0.00001%, the feed to the adsorber (6) is stopped and it is switched to the regeneration mode. The supply of raw materials is carried out in an adsorber (8), which is regenerated and cooled. The adsorber (7) is switched to the cooling mode.

The spent adsorbent is regenerated by a prepared regeneration gas heated in an oven to 320 - 350 ^o C. The adsorber (6) is disconnected from the main stream of the hydrocarbon mixture, which is squeezed out by the cold regeneration gas into an adsorber (8) switched into the adsorption cycle.

When the temperature at the outlet of the adsorber is stabilized at a level of 300 - 315 ^o C, the regeneration is completed. The adsorber (6) switches to cooling.

Example 2. To obtain the hydrocarbon propellants necessary for aerosol packaging of the company’s products, an overpressure of 0.38 - 0.4 MPa and the following composition, mass fraction of components,% are set:
Propane, butane, isobutane, not less than - 99.21
Pentanes, no more - 0,3
Unsaturated hydrocarbons - None
Mass fraction of sulfur compounds, not more than 0.00001
Mass fraction of non-volatile substances, no more than 0.00002
Mass fraction of water, no more - 0,0002.

Hydrocarbon gases of the following composition (mass content,%) are sent to the heat and mass transfer apparatus (1) for preliminary preparation of raw materials (mass content): ethane 2.30; propane 36.75; isobutane 12.3; n-butane 24.1; isopentane 7.15; n-pentane - 8.65; ∑ C _{6 + B} 8.75; water content 0.25 g / m ³ , hydrogen sulfide 0.004 g / m ³ , mercaptans 0.0015 g / m ³ , asphalt-resinous 5 mg / 100 ml. At a top temperature of the apparatus of 40 - 41 ^o C and a pressure of 2.1 MPa, light components are removed (mass content,%: ethane 30.7; propane 65.5; isobutane 2.2; n-butane 1.59; ∑ pentanes 0 01) from raw materials. The raw material thus prepared from the bottom of the heat and mass transfer apparatus (1) enters the unit for producing the propellant composition (2), where at a top temperature of 55.4 ^° C and a pressure of 0.9 MPa, a hydrocarbon mixture of a given composition is obtained (mass content,%): ethane 0 , 49; propane 35.83; isobutane 21.28; n-butane 42.1; the amount of pentanes 0.3, the water content of 0.2 g / m ³ ; hydrogen sulfide 0.0031 g / m ³ ; ethyl mercaptan 0.0006 g / m ³ ; butyl mercaptan 0.0008 g / m ³ ; asphalt-resinous 3 mg / 100 ml. The excess pressure of saturated hydrocarbon vapors is 0.4 MPa, which corresponds to TU 39-892-93 per hydrocarbon propellant.

The resulting hydrocarbon mixture enters one of the adsorbers (3, 4), where asphalt-resinous substances and partially sulfur compounds are completely removed with activated carbon of the AG-2 brand. Next, the hydrocarbon mixture is cleaned on the filter (5) and sent to one of the adsorbers (6, 7, 8), filled with synthetic zeolites NaA, CaA, NaX. The ratio of CaA: NaX layers is 1: 1. At the outlet of the adsorber, the hydrocarbon propellant contains: moisture - 0.0005 g / m ³ , sulfur compounds - 0.000053 g / m ³ (0.00001 wt.%).

The feed rate of the hydrocarbon mixture to the adsorber (6) is 0.0025 m / s at a pressure of 0.85 MPa and a temperature of 45 ^o C. At the same time, the adsorber (7) is in the regeneration mode, and the adsorber (8) is in the cooling mode .

 The obtained hydrocarbon propellant is cleaned of zeolite dust on filters (9, 10) and sent (11) to the finished product warehouse. According to its physical and chemical parameters, the obtained propellant corresponds to TU 39-892-93.

The adsorbent is regenerated and cooled with nitrogen with a residual oxygen content not exceeding 2% vol. At first, the nitrogen flow passes the adsorber (8) with the freshly regenerated zeolite and cools it to 50 ^° C, then this nitrogen passes through heating in the furnace to 320 - 350 ^° C and is fed to the adsorber (7) for zeolite regeneration. When the temperature at the outlet of the adsorber (7) is stabilized at a level of 300 - 315 ^o C, the regeneration is completed and the adsorber is switched to cooling.

Thus, the proposed method for producing hydrocarbon propellants allows you to:
to obtain high-quality hydrocarbon propellants, which is ensured by fine purification from sulfur compounds (the mass content of sulfur compounds in the finished product does not exceed 0.00001%);
expand the range of raw materials using hydrocarbon raw materials containing C ₂ -C ₇ ;
significantly reduce capital and operating costs by replacing apparatuses for producing four individual hydrocarbons and a unit for mixing them with two apparatuses for producing a hydrocarbon mixture of a given composition, extending the service life of zeolites.

Claims (5)

 1. The method of producing hydrocarbon propellants, including the rectification of hydrocarbon raw materials, purification, deodorization and drying, characterized in that during the rectification process a hydrocarbon mixture of a given composition with an excess vapor pressure corresponding to an excess vapor pressure of hydrocarbon propellants is isolated and subjected to preliminary purification and deodorization on activated carbon, and drying is carried out on synthetic zeolites.  2. The method according to claim 1, characterized in that after preliminary purification and deodorization, hydrocarbons are dried, purified and deodorized on synthetic zeolites, followed by regeneration of zeolites.  3. The method according to claim 1, characterized in that the drying, cleaning and deodorization is carried out by passing a mixture of hydrocarbons through sequentially placed layers of zeolites NaA, CaA and NaX.  4. The method according to claim 2, characterized in that the regeneration of zeolites is carried out with nitrogen.  5. The method according to claim 2, characterized in that the regeneration is carried out by dried and purified hydrocarbon gas.