RU2607631C1 - Method for production of liquefied hydrocarbon gases - Google Patents

Abstract

FIELD: gas industry.

SUBSTANCE: invention relates to production of liquefied hydrocarbon gases, including adsorption purification of a broad fraction of light hydrocarbons from sulphur compounds and methanol. Method is characterized by that adsorption purification of liquefied hydrocarbon is implemented in multilayer adsorbers, in which each layer of adsorbent is series-selective in relation to a specific type of extracted impurities, temperature regeneration and subsequent cooling of adsorbents is carried out with a methane fraction, purified from impurities, similar to extracted impurities, and supplied on side, at final stage of cooling of adsorbents, adsorbers are blown with dry high-pressure nitrogen prior to feeding broad fraction of light hydrocarbons into adsorber with regenerated adsorbents, and purified broad fraction of light hydrocarbons undergoes distillation to produce liquefied narrow fractions of light hydrocarbons in system, at least two full rectification columns.

EFFECT: use of present method simplifies and provides universalisation of process diagram of production of liquefied hydrocarbon gases at stage of purification of liquefied gases independently from combination of extracted impurities, reduced power consumption of process and flexible variability of process with formation of a range of final product depending on marketing requirements.

14 cl, 1 tbl, 3 dwg

Description

The invention relates to a technology for the purification of liquid hydrocarbon raw materials from methanol and sulfur compounds and can be used in the gas, oil, oil refining, petrochemical and chemical industries.

In recent years, in connection with increasing exports, the quality requirements for liquefied petroleum gases have been substantially tightened, especially for the allowable content of sulfur compounds and methanol, for example, the concentration of methanol in propane according to EN standards should not exceed 50 ppm.

A known method of purification of light hydrocarbon fractions containing sulfur compounds and carbon dioxide by contacting in a countercurrent absorber in one stage with a circulating modified aqueous solution of alkanolamine, regenerated while maintaining the modifying additive by temperature desorption of carbon dioxide and sulfur compounds, while using as a modifying additive sodium hydroxide in an amount of 0.005-1,000% (patent for the invention RU 2492213 C1, IPC C01G 21/20, C01G 19/02, C01G 19/08, filed January 26, 2018, published 10. 09.2013). The disadvantages of this method are:

- additional energy consumption both in the preparation of the process raw materials and in the use of the final product due to the need for sequential operations of evaporation of a liquid wide fraction of light hydrocarbons (BFLH), purification of gaseous BFLH with an absorbent at a temperature of 35-40 ° С under a pressure of 15 atm, and condensation of BFLH, for example, during further transportation of BFLH for export by tankers, for the implementation of low-temperature distillation to produce BFLH in the liquid phase, which provides preliminary separation of methane and ethane and from the heavier hydrocarbons (C ₃ -C ₄ ) that are part of NGL, despite the fact that the cleaning of a wide fraction of light hydrocarbons is carried out in the gas phase;

- absorption of methanol absorbent with an aqueous solution with its gradual accumulation in the absorption-regeneration cycle in the presence of methanol impurities in NGL;

- additional equilibrium saturation of BFLH with moisture upon contact of the purified BFLH with an aqueous absorbent solution;

- the impossibility of achieving equally deep purification of recoverable carbon dioxide and sulfur compounds, since the absorbent has different absorption selectivity with respect to these impurities.

There is also a method of purifying a wide fraction of light hydrocarbons from mercaptan compounds by reacting mercaptan compounds with an absorbent obtained by mixing an aqueous alkali solution with alkylbenzyldimethylammonium chloride (patent RU 2529203 C2, IPC C01G 19/02, C01G 21/06, filed January 26, 2018 published on 09/10/2013). The disadvantages of this method are:

- additional energy costs in the preparation of the process raw materials and in the use of the final product, which leads to the need for sequential operations of vaporizing liquid BFLH, purifying gaseous BFLH with absorbent material and condensing BFLH, for example, during further transportation of BFLH for export by tankers, the cleaning of a wide fraction of light hydrocarbons is carried out in the gas phase however, since the preliminary separation of methane and ethane from the heavier hydrocarbons (C ₃ -C ₄ ), which are part of NGL, low distillation to obtain BFLH in the liquid phase, for the implementation of this method, it is necessary to liquid BFLH first to evaporate;

- absorption of methanol absorbent with an aqueous solution with its gradual accumulation in the absorption-regeneration cycle in the presence of methanol impurities in NGL;

- additional equilibrium saturation of BFLH with moisture upon contact of the purified BFLH with an aqueous absorbent solution.

A known method of purification of liquefied hydrocarbon gases (LHG) from methanol, including extraction purification of these gases with water and their adsorption drying, in which, after extraction purification from waste water, methanol is distilled off and condensed, and the regenerated water is returned to the extraction purification stage (patent for invention RU 2451538 C1, IPC B01D 53/00, announced on 11/15/2010, published on 05/27/2012). The disadvantages of this method are:

- high energy intensity of the implementation of the method, due to the need to enter a large amount of heat during the distillation of methanol from waste water due to the high heat capacity of water, which is on average twice as high as that of organic extractants;

- the need to implement gas purification processes from methanol and water separately for each type of liquefied petroleum gas upon receipt of several types of LPG at one enterprise;

- increasing the size of the adsorbers and adsorbent loading, which results in an increased water load of the adsorption stage of the process due to the equilibrium flooding of the liquefied hydrocarbon gas purified from methanol at the extraction purification stage.

A common disadvantage of the considered methods of purification of liquefied petroleum gases from methanol, sulfur compounds and water is, firstly, their high energy intensity due to the need to ensure a multi-stage process, including preliminary evaporation of LPG, absorption cleaning and drying or extraction cleaning and drying, and, in -second, the complication of the technological scheme and its maintenance.

The problem to which the claimed invention is directed, is to simplify and universalize the technological scheme for producing liquefied petroleum gases at the stage of purification of liquefied gases, regardless of the combination of recoverable impurities, reducing the energy intensity of the process and providing flexible process variability in the formation of the range of finished products depending on marketing requirements .

The solution to this problem is achieved due to the fact that in the method for producing liquefied hydrocarbon gases, including adsorption purification of a wide fraction of light hydrocarbons from sulfur compounds and methanol, adsorption purification of a liquefied wide fraction of hydrocarbons is implemented in a system of multilayer adsorbers in which each adsorbent layer is sequentially selective with respect to to a specific type of recoverable impurities, temperature regeneration and subsequent cooling of adsorbents is performed by the methane fraction, purified at the final stage of cooling the adsorbents, the adsorbers are purged with high-pressure dry nitrogen before feeding a wide fraction of light hydrocarbons into the adsorber with regenerated adsorbents, and the purified broad fraction of light hydrocarbons is rectified to obtain liquefied narrow fractions of light hydrocarbons. The use of multilayer adsorbers to remove several types of impurities from liquefied hydrocarbon gases, in which each adsorbent layer is sequentially selective with respect to a particular type of impurity to be recovered, makes it possible to more effectively use the specific adsorption properties of adsorbents during the adsorption of one particular impurity to achieve the required high degree of purification, how when using universal adsorbents in the process of purification of the main product in the adsorbent occurs um, desorption by components with high adsorption potential of components with low adsorption potential, which leads to contamination of the product being cleaned or to a substantial increase in the height (and, correspondingly, loading) of the adsorbent layer, which affects the technical and economic performance of the cleaning process due to the growth of capital and operational costs. Carrying out temperature regeneration and subsequent cooling of the adsorbents by the methane fraction obtained during the extraction of a wide fraction of light hydrocarbons from natural gas allows the methane fraction to circulate in the adsorbent regeneration system with a relatively small amount of methane fraction with desorption products used as fuel in the heater of the regenerating methane fraction , which eliminates the need for additional equipment for cleaning regeneration gases from desorbed impurities. Purge of high pressure adsorbers with dry nitrogen at the final stage of cooling the adsorbents before feeding a wide fraction of light hydrocarbons to the adsorber with regenerated adsorbents prevents methane from dissolving in the wide fraction of light hydrocarbons loaded into the adsorbers for subsequent purification, which improves the purity of the resulting liquefied propane. The purified broad fraction of light hydrocarbons is subjected to rectification to obtain liquefied narrow fractions of light hydrocarbons in the system of at least two complete distillation columns, which allows to obtain at least three liquefied narrow fractions of light hydrocarbons, expanding the range of products.

Since the final stage of regeneration is purging the adsorbent layer with nitrogen to remove methane even at a low temperature of the layer of activated adsorbents, it is necessary that nitrogen contain sulfur compounds not more than 1-2 ppm, methanol not more than 1-2 ppm, moisture not more than 0.1-1 ppm, since at significant concentrations of these impurities in nitrogen, sorption of these impurities by adsorbents will begin, which will lead to a decrease in the working adsorption activity of adsorbents and a decrease in the technical and economic parameters of the process (increase in adsorbent loading adsorbers, metal consumption of adsorbers, energy consumption for regeneration of adsorbents).

It is advisable, if there are two types of undesirable impurities in liquefied hydrocarbon gases - sulfur compounds and methanol - that the multilayer adsorbers have two adsorbent layers, while in the direction of movement of the cleaned stream of liquefied hydrocarbon gases in the adsorbers, a layer of medium-porous zeolite NaA or CaA adsorbing methanol is located, and then a layer of broad-porous zeolite NaX or CaX adsorbing sulfur compounds.

If there are three types of undesirable impurities in liquefied hydrocarbon gases - sulfur compounds, methanol and water - it is advisable that the multilayer adsorbers have three adsorbent layers, while in the direction of movement of the cleaned stream of liquefied hydrocarbon gases in the adsorbers, a layer of finely porous KA zeolite sorbing water is located, then a layer of medium-porous zeolite NaA or CaA adsorbing methanol, then a layer of wide-porous zeolite NaX or CaX adsorbing sulfur compounds.

It is advisable that in multilayer adsorbers the direction of movement of the cleaned stream of liquefied hydrocarbon gases is ensured from the bottom up, since when filling the adsorber with the cleaned product at the initial stage of adsorption, the apparatus and layers of the adsorbent are uniformly gradually filled with a liquid phase, which reduces the destruction of the adsorbent granules and the formation of dust microparticles polluting the cleaned stream of liquefied hydrocarbon gases, since the kinetic en rgiya falling jets of liquefied hydrocarbon gases goes into potential energy due to mechanical impact on the adsorbent granules to form dust microparticles. In this case, the methane fraction used in the temperature regeneration and cooling of absorbents is fed into the multilayer adsorbers in the direction opposite to the direction of movement of the cleaned stream of liquefied hydrocarbon gases. In order to guarantee the quality of the obtained liquefied hydrocarbon gases at the outlet of the liquefied hydrocarbon gas stream from the multilayer adsorbers, it is advisable to carry out their filtration purification, which will also prevent the adsorbent particles from clogging the subsequent equipment.

To ensure flexible variability of the process for producing liquefied hydrocarbon gases when forming the assortment of manufactured final products, depending on the requirements of marketing in a system of two full distillation columns, it is advisable:

a) in the first column along the column, from the top of the column, obtain marketable liquefied propane, and from the bottom of the column, a mixture of fractions C ₄ and C ₅ with an admixture of higher boiling hydrocarbons, which is then separated in the second distillation column to obtain marketable liquefied butane and liquid pentane from the bottom -hexane fraction with a slight admixture of higher boiling hydrocarbons;

b) in the first column along the column, discharge commercial liquefied technical propane-butane (SPBT), and from the bottom of the column - the pentane-hexane fraction with a slight admixture of higher boiling hydrocarbons, while part of the SPBT is introduced into the second distillation column as raw material to obtain above liquefied propane, and below butane.

To ensure a high degree of efficiency of the distillation columns, it is advisable to use a regular cross-head nozzle of the PETON system as contact devices in both full distillation columns, which, ceteris paribus, will reduce energy consumption while maintaining the quality of the produced narrow fractions of light hydrocarbons or improve their quality while maintaining energy costs .

To ensure flexible variability of the process of producing liquefied petroleum gases when forming the range of final products depending on marketing requirements, as well as possible fluctuations in the composition of a wide fraction of light hydrocarbons, the introduction of the corresponding raw materials into two full distillation columns can be carried out in the middle part of distillation columns for columns of different heights contact devices, which will allow you to vary the number of contact devices in the upper and lower parts of distillation columns and optimize the technological modes of their operation to reduce energy consumption or improve the quality of the final product. To reduce energy costs, it is also advisable to provide heating and partial evaporation of the raw materials introduced into the corresponding two complete distillation columns due to regenerative heat exchange with products removed from the bottom of these distillation columns.

In figures 1 and 2 presents a schematic diagram of an installation that implements the claimed invention, in which:

10, 20, 30, 40 — adsorber;

50, 60, 270 - dust filter;

70, 90, 150, 220 - capacity;

80, 100, 160, 230 - pump;

110, 180, 280 - recuperative heat exchanger;

120 - column depropanizer;

130, 200, 250 - air cooling apparatus;

140, 210, 260, 300 - water refrigerator;

170, 240 - thermosiphon;

190 - debutanizer column;

290 - oven;

1-9, 11-19, 21-29, 31-39, 41-49, 51-53 - pipelines.

Shown in figures 1 and 2, the installation diagram that implements the claimed invention, operates as follows.

It is conventionally accepted that two adsorbers 10 and 20 work in the adsorption mode, the adsorber 30 is in the regeneration mode, the adsorber 40 is in the cooling mode. The flow of the original BFLH in the amount of 93800 kg / h, containing 0.0002% of the mass. methane, 0.0468% of the mass. methanol and 0.0262% of the mass. sulfur compounds at a temperature of 35 ° C and a pressure of 1.77 MPa through line 1 enters the adsorption purification of BFLH from sulfur compounds and methanol from bottom to top in two parallel adsorbers 10 and 20, each of which contains two layers of adsorbents: in the lower layer is located zeolite type NaA, and in the upper - zeolite type NaX, which sequentially provide purification of NGL from methanol and sulfur compounds.

The stream purified from sulfur compounds and methanol a wide fraction of light hydrocarbons with a content of 0.0002% of the mass. methane, 0.0028% of the mass. methanol and 0.0004% of the mass. sulfur compounds from adsorbers 10 and 20 enters a common reservoir with a temperature of 35 ° C and a pressure of 1.72 MPa. Next, the combined flow of BFLH in the amount of 93703 kg / h through line 2 is sent to the dust filters 60, one of which is in reserve. In dust filters 60, BFLH is cleaned of zeolite microparticles removed from adsorbers.

After filtering, the purified BFLH stream through line 3 enters the tank 70, from which the stream of purified BFLH under a pressure of 1.61 MPa via line 5 is received by the pumps 80. Gases displaced from the adsorber when it is filled with raw materials (BFLH) at the stage of adsorption is carried out through line 7 dumped onto the torch.

From the pump outlet 80, the cleaned BFLH stream in the amount of 93703 kg / h via line 6 is discharged to the tank 90, from which the BFLH stream through line 8 is received by the pumps 100. From the pump outlet 100, the BFLH stream through line 9 enters the regenerative heat exchanger 110, where partially evaporates due to the heat of the flow of the butane-pentane-hexane fraction leaving the cube of the depropanizer column 120 via line 22. The feed stream heated in the recuperative heat exchanger 110 in the amount of 93703 kg / h enters through the line 11 into the middle part of the distillation column-depropanizer 120, where did there is a separation of propane from NGL.

Heat is supplied to the cube of the depropanizer column 120 by circulating the bottom stream of the column along lines 19 and 20, heated by means of the AMT-300 heat carrier in a thermosiphon 170.

A propane vapor stream in an amount of 132968 kg / h at a temperature of 55 ° C and a pressure of 1.89 MPa is discharged via line 12 from the top of the depropanizer column 120, condensed in an air cooling apparatus (ABO) 130, and through line 13 it enters the after-cooling in a water cooler 140 and then on line 14 with a temperature of 35 ° C is sent to the tank 150.

From a container 150, a propane stream at a pressure of 1.84 MPa via line 16 is supplied to a pump 160 and then with a pressure of 2.33 MPa and a temperature of 35 ° C in an amount of 77154 kg / h as irrigation through line 17 to a depropanizer 120, and the balance amount of propane in the amount of kg / h is removed from the installation in the tank farm along line 18.

A stream of butane-pentane-hexane fraction from the bottom of the depropanizer column 120 in an amount of 37889 kg / h with a temperature of 120 ° C and a pressure of 1.93 MPa is supplied through line 22 to regenerative heat exchangers 110, where it is cooled to 53 ° C, and then line 23 is fed to recuperative heat exchangers 180, where it is heated to 65 ° C by a stream of pentane-hexane fraction coming in line 36 from the cube of a distillation column-debutanizer 190. A heated stream of butane-pentane-hexane fraction through line 24 is introduced into the feed zone of the column-debutanizer 190 .

Heat is supplied to the cube of the debutanizer column 190 by circulating the bottom stream of the column along lines 34 and 35, which is heated with the AMT-300 heat carrier in a thermosiphon 240.

The stream of butane vapor from the top of the debutanizer column 190 in an amount of 49733 kg / h at a pressure of 0.80 MPa and a temperature of 65 ° C passes through line 25 to an air-cooled apparatus 200, condenses in it and flows through line 26 to post-cooling to 40 ° C to the water cooler 210, then, via line 27, it is sent to the tank 220. Non-condensed vapors from the tank 220 are discharged to the flare via line 28.

From a tank 220, a stream of butane fraction with a pressure of 0.75 MPa and a temperature of 40 ° C is sent through line 29 to the reception of pumps 230 and through line 31 with a pressure of 1.24 MPa in an amount of 23948 kg / h as an irrigation to the debutanizer column 190 and the balance amount of butane via line 32 in the amount of 25785 kg / h enters the water cooler 300 and, after cooling to 34 ° C, is removed from the installation to the tank farm along line 33.

The flow of the pentane-hexane fraction is diverted from the bottom of the debutanizer column 190 through line 36, is cooled in a recuperative heat exchanger 180, is sequentially cooled through lines 37 and 38, respectively, in an air cooling apparatus 250 and a water cooler 260 and through line 39 enters the tank farm.

As the cooling gas, purge gas, and regeneration gas, the methane fraction coming from the factory network via line 41 is used on the NGL purification unit from sulfur compounds.

The regeneration stage is carried out according to the scheme described below. A part of the total methane fraction stream enters through line 43 in an amount of 15953 kg / h at a temperature of 25 ° C and a pressure of 2.45 MPa for heating to 115 ° C in a regenerative heat exchanger 280, then through line 44 it enters an oven 290, where it is heated to regeneration temperature and through line 45 with a temperature of the order of 300 ° C is supplied to the collector of adsorbers as a regeneration gas.

Saturated with methanol and sulfur compounds, the adsorbent, which has lost activity, undergoes regeneration. To regenerate zeolite, the adsorber 30 is preliminarily freed from BFLH by process nitrogen in an amount of up to 7000 m ³ / h with a pressure of 2.36 MPa at a temperature of 50 ° C, which is supplied via line 46. The adsorber is liberated (description is given for adsorber 30, for adsorbers 10 , 20, 40 similarly) from BFLH by transferring the BFLL liquid phase from the adsorbent layers with nitrogen from top to bottom to the collector of purified BFLH and then to the loading and unloading tank (not shown in the diagram). If necessary, crude BFLH is squeezed out of this container by high pressure nitrogen through the filling line (backward) into the adsorber, which must be filled after the regeneration and cooling stage.

After emptying the adsorber, the adsorber is purged with a stream of methane fraction from line 42 from top to bottom. Purge is designed to remove residues of NGL from the space between the zeolite granules and “dry” the granules. The purge gas (methane fraction) after the adsorber 30 enters through line 47 to the dust filters 50, in which it is cleaned of zeolite dust and discharged through line 49 to the fuel network.

After purging the adsorber, zeolite is regenerated by supplying regeneration gas from furnace 290 along line 45 to adsorber 30 from top to bottom.

Regeneration gas in an amount of 16319 kg / h at a temperature of 228 ° C and a pressure of 2.15 MPa in a mixture with 0.8281% of the mass. sulfur compounds and 1.412% of the mass. methanol from adsorber 30 enters the common collector and then goes along line 51 to dust collectors 270, one of which is in reserve. In the dust filters 270, the regeneration gas is purified from the microparticles of zeolite granules carried away from the adsorber.

The zeolite dust purified from the regeneration gas via line 52 then enters the recuperative heat exchanger 280, where the regeneration gas gives its heat to the flow of methane fraction directed to the furnace 290, and then is removed from the unit to the reception of the booster compressor station via line 53.

After regeneration, the zeolite is cooled by a stream of methane fraction, which is supplied to the adsorber via line 42 (the description is taken on the example of adsorber 40, for adsorbers 10, 20, 30 similarly) from top to bottom.

Cooling gas (purge gases when the adsorber is purged from residues of NGL and when inert gas is purged) from the adsorber through line 40 enters the common collector and then goes to dust filters 50, one of which is in reserve. In the dust filters 50, the cooling gas is purified from the microparticles of zeolite granules carried away from the adsorber.

The cooling gas purified from zeolite dust is then output to the BCS via line 48. A line is also provided for the output of cooling gas to the fuel network via line 49.

After cooling, the adsorber 40 is purged with an inert gas to prevent methane from dissolving in NGL. A stream of high pressure nitrogen flows through line 46 from top to bottom in the adsorber. An inert purge gas (high pressure nitrogen) discharged from the adsorber 40 is cleaned of zeolite dust in the dust filters 50 and discharged to the fuel network via line 49.

After purging the adsorber with an inert gas, the adsorber 40 is filled with the BFLH stream from the bottom up from the tank (not shown in the diagram).

The process flow chart is shown in figure 3.

Example. Mathematical modeling of the method for producing liquefied hydrocarbon gases using BFLH as a raw material in the amount of 93,800 kg / h, containing 0,0002% of the mass. methane, 0.0468% of the mass. methanol and 0.0262% of the mass. sulfur compounds, with sequential adsorption purification of BFLH from methanol and sulfur compounds and gas fractionation to obtain liquid propane, butane and a pentane-hexane fraction according to the claimed invention, implemented in the installation according to the technological scheme shown in figures 1 and 2 in accordance with the above technological mode .

The regular crossflow nozzle of the PETON system was used as contact devices in both complete distillation columns.

The calculated characteristics of the main technological flows of the installation (costs, component composition, temperature, pressure) obtained as a result of mathematical modeling of the process are shown in Table 1, from which it follows that during the adsorption purification of BFLH, the content of methanol and sulfur compounds in it decreases by 30 and 65 times, respectively, ensuring the purity of the resulting liquefied propane, butane and pentane-hexane fraction.

Thus, the claimed invention allows for the development of commercial products - liquefied petroleum gases - including the production of propane and butane with sulfur compounds up to 10 ppm and methane not more than 10 ppm, which meets the most stringent requirements of EN.

Claims (14)

1. A method of producing liquefied hydrocarbon gases, including adsorption purification of a wide fraction of light hydrocarbons from sulfur compounds and methanol, characterized in that the adsorption purification of a liquefied wide fraction of hydrocarbons is implemented in a system of multilayer adsorbers in which each adsorbent layer is sequentially selective with respect to a particular type of extractable impurities, temperature regeneration and subsequent cooling of the adsorbents is performed by a methane fraction purified from the presence of impurities, an analog at the final stage of the adsorbent cooling, adsorbers are purged with high-pressure dry nitrogen before feeding a wide fraction of light hydrocarbons into the adsorber with regenerated adsorbents, and the purified wide fraction of light hydrocarbons is subjected to rectification to obtain liquefied narrow fractions of light hydrocarbons in the system, at least two complete distillation columns. 2. The method according to p. 1, characterized in that the nitrogen for purging methane contains sulfur compounds of not more than 1-2 ppm, methanol not more than 1-2 ppm, moisture not more than 0.1-1 ppm. 3. The method according to p. 1, characterized in that the multilayer adsorbers have two layers of adsorbent. 4. The method according to p. 3, characterized in that in the two-layer adsorbers in the direction of movement of the cleaned stream of liquefied hydrocarbon gases, a zeolite layer of NaA or CaA is first placed, and then a layer of zeolite of NaX or CaX. 5. The method according to p. 1, characterized in that the multilayer adsorbers have three layers of adsorbent. 6. The method according to p. 5, characterized in that in the three-layer adsorbers in the direction of movement of the cleaned stream of liquefied hydrocarbon gases, a CA zeolite layer is first placed, then a NaA or CaA zeolite layer and then a NaX or CaX zeolite layer. 7. The method according to p. 1, characterized in that in multilayer adsorbers the direction of movement of the cleaned stream of liquefied hydrocarbon gases is provided from the bottom up. 8. The method according to p. 1, characterized in that the methane fraction used in the temperature regeneration and cooling of absorbents is fed into the multilayer adsorbers in the direction opposite to the direction of movement of the cleaned stream of liquefied hydrocarbon gases. 9. The method according to p. 1, characterized in that at the outlet of the stream of liquefied hydrocarbon gases from the multilayer adsorbers, they are filtered. 10. The method according to p. 1, characterized in that in a system of two complete distillation columns in the first along the column from the top of the column receive commodity liquefied propane, and from the bottom of the column - a mixture of fractions C ₄ and C ₅ mixed with higher boiling hydrocarbons, shared then in the second distillation column to obtain liquefied butane on top of the commodity, and a pentane-hexane fraction with a slight admixture of higher boiling hydrocarbons from the bottom of the column. 11. The method according to p. 1, characterized in that in a system of two complete distillation columns in the first column along the column, technical liquefied technical propane-butane (SPBT) is withdrawn from the top of the column, and a pentane-hexane fraction with a slight admixture of higher boiling hydrocarbons is removed from the bottom , while part of SPBT as a raw material is introduced into the second distillation column to obtain liquefied propane from the top of the column, and butane from the bottom. 12. The method according to p. 1, characterized in that as a contact device in two full distillation columns using a regular cross-flow nozzle system "PETON". 13. The method according to p. 1, characterized in that the input of the corresponding raw materials into two full distillation columns can be carried out in the middle part of the distillation columns at different height of the columns of the contact device. 14. The method according to p. 1, characterized in that the heating and partial evaporation of the raw materials introduced into the corresponding two complete distillation columns, provide due to the regenerative heat exchange with products removed from the bottom of these distillation columns.

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