RU2734376C1 - Method of liquefying gas and installation for implementation thereof - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: invention relates to cryogenic equipment. Method consists in the fact that gas drying, cleaning, cooling and liquefaction processes are carried out in two parallel crimps operating alternately in cooling or heating modes. High pressure compressed gas is fed into cryogenic block, in which it is cooled using cold flow of purge gas. Then, gas is cooled by recoil cold recovery, liquefied components, crystalline hydrates are separated, then high pressure gas stream is separated into process and production streams. Process flow is supercooled by expansion in expander, filtered, mixed with uncondensed gas flow and fed backflow. Production flow is cooled, impurities which have passed into crystalline state are separated in filter-separator, condensed, filtered in filter-trap, throttled and separated formed vapour-liquid flow to vapour and liquid phases in separating accumulator. Non-condensed stream is mixed with supercooled process gas flow. Portion of the return flow is supplied to an inlet of low pressure of the expander.EFFECT: invention increases efficiency of natural gas liquefaction process, reduces value of specific electric power consumption, simplifies instrumentation of the process.2 cl, 1 dwg

Description

The invention relates to cryogenic technology, namely to the technology of purification, cooling and liquefaction of gases and their mixtures, mainly natural gas, at gas distribution stations (GDS), automobile gas filling compressor stations (CNG filling stations), in transportation systems and long-term storage of liquefied gases, at oil fields for separation of associated petroleum gas into stable gas condensate and dry stripped gas.

Known installations and methods for the liquefaction of natural gas, providing in the aggregate drying, purification of high-pressure gas, dividing it into production and process streams, cooling in heat exchangers, expansion in an expander (machine expander), separation of a vapor-liquid stream into vapor and liquid phases in a collector - liquefied gas separator, RU # 2678236 C1, F25J 1/00, 01/24/2019; RU # 2671665 C1, F25J 1/00, 06.11.2018; RU No. 2656068 C1, F25J 1/00, F25J 1/02, 01.06.2018; RU # 2541360 C1, F25J 1/00, 10.02.2015; RU # 2538192 C1, F25J 1/00, 01/10/2015.

There is a known method of partial liquefaction of natural gas, including dividing a high-pressure natural gas stream into process and product streams, throttling the product gas stream after cooling to form a vapor-liquid mixture, separating the vapor-liquid mixture into vapor and liquid phases, followed by directing uncondensed natural gas into the reverse stream, expansion of the process gas flow with a decrease in its temperature and its return in a reverse flow with cooling of the product gas flow, characterized in that the product gas flow is dried and purified from CO ₂ before successive gas cooling in the preliminary, main and additional heat exchangers, and the process gas flow is dried , cooled, and then expanded in the throttle valve of the first stage, then additionally cooled, expanded in the throttle valve of the second stage and mixed with the reverse flow heated in an additional heat exchanger for several condensed natural gas, and the gas temperature in front of the throttle valve of the second stage is chosen as the minimum permissible, at which there is no crystallization of CO ₂ after the gas passes through the throttle valve of the second stage (RU 2499208 C1, publ. 11/20/2013, IPC F25J 1/00).

The disadvantage of this method is that the gas is expanded using a passive expansion device (choke). As is known, in passive expansion devices, gas expansion occurs along the isenthalp without performing useful mechanical work. The throttling temperature decreases in accordance with the Joule-Thomson choke effect. The magnitude of this effect is not large and averages about 7 ° C per 1 MPa of pressure drop. Therefore, for cooling to the cryogenic temperature of gas liquefaction, it is required to create a high pressure of compressed gas up to 25 MPa. This is a disadvantage, since it requires a special design of heat exchangers, the use of expensive austenitic steels, an increase in wall thickness, an increase in the mass and cost of heat exchangers.

The closest, taken as a prototype, is a method for liquefying natural gas according to patent RU 2438081 C2, publ. 12/27/2011, IPC F25J 1/00, including the separation of the high-pressure natural gas stream into process and product streams, expansion of the process gas flow with a decrease in its temperature and its return flow with cooling of the product gas flow, throttling of the product gas flow after its cooling from the formation of a vapor-liquid mixture, separation of a vapor-liquid mixture into vapor and liquid phases, followed by directing uncondensed natural gas into the reverse flow, characterized in that the product gas stream is dried and purified from CO ₂ before cooling, and the process gas stream is dried and cooled to a temperature before expansion , the value of which is chosen from the conditions of the greatest degree of gas liquefaction in the absence of CO ₂ crystallization in natural gas after its expansion.

The disadvantage of the prototype is the limitation on the temperature of the process stream after expansion. It is known that the cooling capacity of the entire process depends on the temperature of the cooling stream. At the same time, each temperature has its own maximum capacity for liquefied gas. The lower the temperature of the cooling stream, the higher the maximum capacity for LPG. In the prototype, the process gas stream is expanded and cooled to a temperature whose value is selected from the conditions of the greatest degree of gas liquefaction in the absence of CO ₂ crystallization in the process gas stream after its expansion. Since the prototype sets an additional temperature limitation on the condition of CO ₂ crystallization, the degree of gas liquefaction is less than it could be in the absence of a limiting factor. This is a disadvantage, since it prevents a further increase in the productivity of liquefied natural gas and a decrease in the value of the unit cost of electricity per kilogram of liquefied gas.

The disadvantage of the prototype, in addition, is the applied method of expanding the process gas flow. In the prototype, the gas is expanded using a machine expander. As you know, despite their high efficiency, machine expanders based on the use of mechanisms with moving internal parts have much lower reliability compared to machineless expansion devices, since they require a mandatory load during operation (brake, generator, compressor, etc. .), require monitoring the speed of the impeller and cooling the bearings, require periodic maintenance and repair, and have a short service life. This is a disadvantage, since it reduces the reliability of the entire installation as a whole.

The closest to the proposed installation is a plant for the liquefaction of natural gas (RU 2438081 C2, publ. 27.12.2011, IPC F25J 1/00), containing a high pressure gas pipeline connected to the inlet of the process gas flow line, including a gas flow expansion device, and the inlet of the product gas flow line, which includes a series-connected preliminary and main heat exchangers, a throttle valve and a collection-separator of liquefied gas, the first outlet of which is intended for dispensing liquefied gas, and the second outlet is connected to the inlet of the gas return flow line, which includes the main and preliminary heat exchangers connected in series , the second inlet of the main heat exchanger is the inlet of the gas return flow line, the second outlet of the preliminary heat exchanger is connected to the low pressure gas pipeline, the product gas flow line has a first drying unit and a gas flow purification unit connected in series, and the process flow line ka gas is equipped with a second block for drying the gas flow and is made with the inclusion of a preliminary heat exchanger in it, and the input of the first block for drying the gas flow is the input of the product gas flow line, and the outlet of the gas purification unit is connected to the first input of the preliminary heat exchanger, the input of the second block the inlet of the process gas flow line, and its outlet is connected to the third inlet of the preliminary heat exchanger, the third outlet of which is connected to the inlet of the expansion device connected by the outlet to the second inlet of the main heat exchanger.The prototype allows to obtain liquefied natural gas with a low content of carbon dioxide and other high-boiling components using a simplified technology at a relatively high content of carbon dioxide in the initial high-pressure gas, due to the fact that the process gas stream before expansion is dried and cooled to a temperature whose value is selected from the conditions of the greatest degree of gas liquefaction at due to the crystallization of CO ₂ in natural gas after its expansion. This improves the quality of the liquefied natural gas produced, eliminates the possibility of carbon dioxide crystallization and clogging of equipment, and ensures the continuity of production. However, the prototype has the following disadvantages.

The disadvantage of the prototype is also the complexity of the hardware design, determined by the presence of a separate drying unit for the process flow, as well as drying and cleaning units for the product flow, and each of the drying and cleaning units of the process and product gas streams consists of two switchable adsorbers with an adsorbent regeneration system and a preliminary cooling of the dried gas. The complexity of the technological process entails an increase in the cost of technological equipment and the cost of the produced liquefied gas with additional costs of heat and electricity spent on the regeneration of adsorbents.

The technical problem solved by the claimed technical solution is to increase productivity, reduce energy consumption, simplify hardware design, increase reliability, reduce weight and size characteristics and cost of technological equipment.

The problem is solved by the fact that in the known method of natural gas liquefaction, which includes dividing the high-pressure natural gas stream into process and product streams, expanding the process gas stream with a decrease in its temperature and returning it in a reverse flow with cooling the product gas stream, throttling the product gas stream after its cooling with the formation of a vapor-liquid mixture, separation of the vapor-liquid mixture into vapor and liquid phases, followed by directing uncondensed natural gas into the reverse flow, the product gas stream before cooling is dried and purified from CO ₂ , and the process gas stream is dried and cooled to a temperature before expansion, the value of which is selected from the conditions of the greatest degree of gas liquefaction in the absence of crystallization of CO ₂ in natural gas after its expansion, part of the low pressure return flow is fed to the low pressure inlet of the expander, the process flow is high This pressure is supplied to the high-pressure inlet of the expander, the expansion of the process gas stream is carried out in the expander without limiting the minimum attainable temperature of the process stream according to the condition of CO ₂ crystallization, and drying, cleaning, cooling and liquefaction of the gas is carried out alternately in two parallel cryoblocks operating in cooling modes or heating, and the processes of drying and cleaning the technological and production gas streams from impurities are carried out directly in the cooling cycle by the methods of low-temperature filtration and separation.

The technical result that provides a solution to the problem is achieved by using a new set of features of the claimed method and installation that implements this method.

An increase in the productivity of liquefied gas and a decrease in the specific consumption of electricity is achieved by the fact that in the proposed method of liquefying gas, the temperature limitation is removed from the condition of the absence of CO ₂ crystallization when the process stream is expanded. In this regard, the proposed method provides for the expansion of the process flow with supercooling of the expanded flow below the crystallization point of CO ₂ , while the processes of drying, cleaning, cooling and liquefaction of gas are carried out not in a separate absorption unit, but directly in our own gas liquefaction plant using low-temperature filtration methods and separation after crystallization during cooling. For this, the processes are carried out in two parallel cryoblocks, working alternately in cooling or warming modes. Compressed natural gas of high pressure is supplied to the first cryoblock operating in the cooling mode, in which it is cooled using the coldness of the purge gas stream obtained by purging the second cryoblock operating in the warming up mode. Next, the gas is cooled due to the recuperation of the reverse flow cold, the liquefied high-molecular components and crystalline hydrates are separated in a coalescer filter. Then the high-pressure gas stream is separated into process and product streams. The process stream is subcooled by expansion in an expander without limiting the minimum attainable gas temperature by the condition of crystallization of carbon dioxide, filtered from the crystalline phase of CO ₂ , mixed with the vapor phase stream coming from the liquefied gas storage separator, and fed back to cool the product stream. The product stream is filtered from impurities that have transformed into a crystalline state in a filter-separator, condensed, heavy impurities that have passed into a crystalline state in a trap filter are separated, throttled and the formed vapor-liquid flow is separated into vapor and liquid phases in a storage separator. The vapor phase stream is mixed with a subcooled low pressure gas stream after the gas-dynamic expander and the mixture is directed to the reverse stream. When the filters-separators and filters-coalescers are filled with the crystalline phase of CO ₂ and crystalline hydrates, the cryoblock is transferred to the regeneration and heating mode, and the liquefaction process is continued in the cryoblock that has undergone regeneration and heating. This makes it possible to remove the accumulated crystalline phase from heat exchangers and filters, while the heat of sublimation of the crystalline phase of CO _{2 is} used for additional cooling of the compressed gas flow, and the heat of the compressed gas, in turn, is useful for warming up the cryoblock removed from operation. Thus, the proposed method makes it possible to reduce the temperature of the supercooled process stream after expansion, to increase the productivity of liquefied natural gas and to reduce the unit cost of electricity per kilogram of liquefied gas.

The technical result in terms of simplifying the hardware design is achieved by eliminating the absorption units for drying and purifying the liquefied gas and combining the drying and purification of the liquefied gas with the cooling and liquefaction processes, by replacing the adsorption processes with low-temperature separation and filtration processes.

The technical result, both in terms of increasing reliability and in terms of reducing the weight, size and cost characteristics of the equipment, is also achieved through the use of the gas expansion process in the expander. In active expansion devices (expanders), expansion occurs with the performance of useful mechanical work close to an isentropic process. In this case, the temperature effect is much greater than when expanding in passive expansion devices (chokes), in which expansion occurs along the isenthalp. High efficiency of expansion in expanders allows to obtain high refrigerating power at relatively low pressures of compressed gas. However, in spite of their high efficiency, machine expanders based on the use of mechanisms with movable internal parts are significantly less reliable in comparison with machineless expanders. In the proposed method, the process of expansion of compressed gas occurs in a special machine-less expander, which does not have rotating mechanisms, but is distinguished by the ability to supercool the gas with a temperature effect that is slightly inferior to machine expanders. Expansion of the process gas flow in a machine-less expander makes it possible to reduce the available initial pressure of the compressed gas flow to a value at which it is possible to use aluminum alloys in the design of heat exchangers and to reduce the wall thickness. This reduces the weight and cost of heat exchange equipment. The absence of rotating and moving parts increases the reliability of the entire installation.

The stated solution (installation) is illustrated by a drawing, where

FIG. 1 shows a block diagram of a gas liquefaction plant.

In the drawing, the reference numbers show: 1 High pressure gas flow inlet line, 2 Low pressure gas flow outlet line, 3 Low pressure product flow line, 4 Storage separator, 5 Liquefied gas flow outlet line (first outlet from storage separator 4), 6 Vapor phase flow outlet line (second outlet from storage separator 4), 100 Cryoblock in cooling mode, 101 Additional heat exchanger (cryoblock 100), 102 Pre-cooling heat exchanger (cryoblock 100), 103 Filter coalescer (between heat exchangers 102 and 104), 104 Deep cooling heat exchanger (cryoblock 100), 105 Filter separator (at the outlet of the heat exchanger 104), 106 High pressure product flow line (when separating line 1 after the coalescer filter 103), 107 High pressure process flow line (when separating line 1 after coalescer filter 103), 108 expander (cryoblock 100), 109 Low pressure process flow line, 110 Filter separator (on line 109), 111 Product stream condensation heat exchanger (cryoblock 100), 112 Filter-trap (after heat exchanger 111), 113 Throttle (after filter-trap 112), 114 Low pressure return flow line (cryoblock 100), 115 Line inlet to the expander of low pressure gas flow ( downstream of the product gas condensation heat exchanger 111), 116 Low pressure return flow outlet line (connected to the outlet from the shell side of heat exchanger 102), 117 Outlet line of the warm gas purge flow (connected to the outlet from the shell side of the heat exchanger 101), 200 Cryoblock in heating mode 201 ...

Additional heat exchanger (cryoblock 200), 202 Pre-cooling heat exchanger (cryoblock 200), 203 Coalescer filter (between heat exchangers 202 and 204), 204 Deep cooling heat exchanger (cryoblock 200), 205 Filter separator (at the outlet of the heat exchanger 204), 206 Line high pressure product stream (when dividing line 217 after the coalescer filter 203), 207 High pressure process flow line (when splitting line 217 after the coalescer filter 203), 208 Machineless gas dynamic expander (cryoblock 200), 209 Low pressure process flow line, 210 Filter separator (on line 209), 211 Heat exchanger for condensation of the product stream (cryoblock 200), 212 Filter trap (after heat exchanger 211), 213 Throttle (behind filter trap 112), 214 Purge gas return flow line (cryoblock 200) , 215 Inlet line to the expander of the low pressure gas flow (after the heat exchanger for condensation of product gas 211), 216 Outlet line of the purge th flow of cold gas (connected to the outlet from the shell side of the heat exchanger 202), 217 Inlet line of the purge stream of warm gas (connected to the inlet to the tube space of the heat exchanger 202).

The gas liquefaction plant contains two cryoblocks: cryoblock 100 and cryoblock 200. Cryoblocks are located in parallel and have the ability to alternately operate in cooling or heating modes to combine the drying and purification of liquefied gas with cooling and liquefaction processes. Cryoblock 100 (in cooling mode) contains an additional heat exchanger 101 connected at the inlet of the tube space with the inlet line of the high pressure gas flow 1, and at the inlet of the annular space with the outlet line of the purge flow of cold gas 216 of the cryoblock 200. After the additional heat exchanger 101, a heat exchanger of the preliminary cooling 102 and a deep cooling heat exchanger 104, between which a filter coalescer 103 is located. In this case, at the outlet of the deep cooling heat exchanger 104, filter separator 105. After the coalescer filter 103, the high pressure gas flow line 1 is divided into a high pressure process flow line 107 and a high pressure product flow line 106. The high pressure process flow line 107 is connected to the inlet of the expander 108, at the outlet of which a filter is installed. separator 110. And the line of the high-pressure product stream 106 is connected to the inlet of the deep-cooling heat exchanger 104, after which the filter-separator 105, the condensation heat exchanger of the product gas 111, the filter-trap 112 and the throttle 113, connected by the line of the low pressure product stream 3 to the inlet storage separator 4. The storage separator 4 has two outlets: the first connected to the liquefied gas flow outlet line 5, and the second to the vapor phase flow outlet line 6. The vapor phase flow outlet line 6 is configured to mix the vapor phase flow with the process low pressure flow from line 1 09, with the formation of a low pressure backflow in line 114 connected to the shell side of heat exchangers 111, 104 and 102. The shell side outlet of heat exchanger 111 is connected through line 115 to the low pressure inlet of gas dynamic expander 108. The shell side outlet of heat exchanger 102 is connected through line 116 to low pressure gas flow outlet line 2. Cryoblock 200 equipment is placed in a mirror-like arrangement relative to cryoblock 100 equipment. Cryoblock 200 (in heating mode) contains an additional heat exchanger 101 (in heating mode it is turned off), a preliminary cooling heat exchanger 202 and a deep cooling heat exchanger 204, between which a coalescer filter 203 is located. The outlet of the coalescer filter 203 is connected to the inlet of the deep cooling heat exchanger 204 by line 206 and to the high pressure inlet of the gas dynamic expander 208 by line 207. At the outlet of the deep cooling heat exchanger 204, filter separator 205, heat exchanger for condensation of high pressure product stream 211, trap filter 212. The outlet of the trap filter 212 is connected to the inlet to the shell side of the heat exchanger 211 by line 218. In the heating mode, the lines connecting the cryoblock 200 with the storage separator 4 are disconnected. The outlet of the expander 208 is connected to the inlet of the filter-separator 210 by line 209, and the outlet of the filter-separator 210 is connected to the inlet to the annular space of the heat exchanger 211 by the line 214. The outlet of the annular space of the heat exchanger 211 through line 215 is connected to the low pressure inlet of the gas dynamic expander 208. The outlet of the annular space of the heat exchanger 202 through line 216 is connected to the inlet to the shell side of the heat exchanger 101 of the cryoblock 100. The preheating heat exchanger 202 at the inlet of the pipe space is connected by the inlet line of the warm gas purge flow 217 to an external gas blower (not shown in the block diagram), which circulates the purge gas, with the possibility of using the heat obtained during the heat exchange of the cold gas outlet stream from line 216 with the high pressure gas stream from line 1 in the heat exchanger 101 of the cryoblock 100.

Description of the installation and the implementation of the gas liquefaction method.

Cryoblocks 100 and 200 of the gas liquefaction unit are switched alternately from the cooling mode to the warming up mode. In the cooling mode, cooling, drying, purification, crystallization of impurities and gas liquefaction are carried out. Moreover, the processes of drying and cleaning are carried out directly in the cooling cycle by methods of low-temperature filtration and separation. In the heating mode, sublimation and removal of impurities accumulated during the period of operation in the cooling mode are carried out. The high-pressure gas stream through line 1 is supplied to an additional heat exchanger 101 of the cryoblock 100 operating in the cooling mode, in which it is cooled using the cold of the cold purge gas stream from the line 216 obtained by purging the cryoblock 200 operating in the heating mode. Next, the high-pressure gas stream is fed to the pre-cooling heat exchanger 102, in which it is cooled by recuperating the cold of the return flow from the line 114, the liquefied high-molecular components and crystalline hydrates are separated in the coalescer filter 103, then the high-pressure gas stream is divided into the high-pressure process stream 107 and high pressure product stream 106. High pressure product stream 106 is cooled in deep cooling heat exchanger 104, filtered in filter separator 105. High pressure process stream 107 is subcooled by expansion in expander 108 without limiting the minimum attainable gas temperature by the condition of carbon dioxide crystallization, after which the low pressure process stream 109 is filtered from the crystalline phase of CO ₂ in the filter separator 110, mixed with the vapor phase flow from line 6 coming from the storage separator 4 and fed through the return flow line 114 to the shell side heat exchange nick 111 for condensation of the high-pressure product stream supplied to the pipe space from line 106. The high-pressure product stream 106 is condensed in the heat exchanger 111, the heavy impurities converted into a crystalline state in the trap filter 112 are separated, expanded in the throttle 113 and the formed two-phase product stream is fed low pressure through line 3 into the storage separator 4 for separation into vapor and liquid phases. The vapor stream from line 6 is mixed with the subcooled low pressure process stream from line 109 and the mixture is directed to low pressure return line 114. After heat exchanger 111, part of the return flow through line 115 is directed to the low pressure inlet of gas dynamic expander 108. The rest of the return flow after recuperation is directed to the low-pressure line 116 and removed from the unit via line 2. Liquefied gas is removed from the storage separator via line 5, the purge gas is removed via line 117. When filling the filter-separators and coalescer filters with the crystalline phase of CO ₂ and crystalline hydrates, the cryoblock 100 is transferred to the regeneration and heating mode, and the liquefaction process is continued in the cryoblock 200, which has undergone regeneration and heating.

In the heating mode, a purge stream of warm gas is supplied to the cryoblock 200 through line 217 and its heat is used to warm up heat exchangers 202, 204 and 211, a coalescer filter 203, a filter-separator 205, a gas-dynamic expander 208, a filter-separator 210, a filter-trap 212 with the formation of a purge flow of cold gas, which is fed through line 216 to the shell side of additional heat exchanger 101 of cryoblock 100 to cool the high pressure gas flow from line 1.

The claimed invention carries out gas liquefaction, has the possibility of alternating operation of two cryoblocks in cooling and heating modes, removes crystallizing impurities not in a separate absorption unit, but directly in its own gas liquefaction unit using low-temperature filtration and separation methods after crystallization during cooling.

The use of this technical solution makes it possible to increase the productivity of the gas liquefaction process, which has a high content of carbon dioxide in the initial composition, to reduce the value of the unit energy consumption, to simplify the instrumentation of the process, to increase reliability, and also to reduce the weight and size characteristics and the cost of technological equipment.

The decision was confirmed by design and technological studies, testing of prototypes, study and justification of operating conditions, which, according to the applicant, determines the compliance of the invention with the criterion of "industrial applicability".

Claims (2)

1. A method of gas liquefaction, in which the direct high pressure gas stream is cooled using the cold of the purge gas stream, then cooled using the cold of the reverse low pressure gas stream, filtered from impurities that have turned into a liquid state, the direct stream is divided into process and production streams, the process stream is subcooled by expansion, filtered from impurities that have transformed into a crystalline state, mixed with the vapor phase flow coming from the storage separator, and fed back to cool the product stream, while the product stream is condensed using the cold of the supercooled process stream, filtered from liquid mercury and impurities that have transformed into a crystalline state are throttled and the formed vapor-liquid flow is separated into vapor and liquid phases, the vapor phase flow is mixed with a supercooled process flow of low pressure gas and the mixture is directed into a reverse flow, characterized in that part of the reverse about the low pressure stream is fed to the low pressure inlet of the expander, the high pressure process stream is fed to the high pressure inlet of the expander, the expansion of the process gas stream is carried out in the expander without limiting the minimum attainable temperature of the process stream by the condition of CO ₂ crystallization, and drying, cleaning, cooling and liquefaction gas is carried out alternately in two parallel cryoblocks operating in cooling or warming modes, and the processes of drying and purification of technological and production gas streams from impurities are carried out directly in the cooling cycle by low-temperature filtration and separation methods. 2. Gas liquefaction plant, including a high-pressure gas flow line, process and product gas flow lines, a low-pressure gas return flow line, a liquefied gas flow outlet line, preliminary and deep cooling heat exchangers, an expansion device, a reducing device and a storage separator, characterized by the fact that the installation contains two cryoblocks, parallel and having the possibility of alternating operation in cooling or heating modes and combining the processes of drying and cleaning the liquefied gas with the processes of cooling and liquefaction, wherein The cryoblock operating in the cooling mode contains an additional heat exchanger connected at the inlet with the high pressure gas flow line, after which a pre-cooling heat exchanger and a deep cooling heat exchanger are located in series, between which there is a coalescer filter, after which the high pressure gas flow line is divided into a high pressure process flow line connected to the inlet of the expander, at the outlet of which a filter separator is installed, and to a high pressure product flow line connected to the inlet of the deep cooling heat exchanger, at the output of which filter separator, product gas condensation heat exchanger, trap filter and throttle with the ability to interact with the low pressure product gas flow line connected to the inlet of the storage separator having two outlets: the first connected to the liquefied gas flow outlet line, and the second with the outlet line of the vapor phase flow, made with the possibility of mixing with the low-pressure process stream after the expander, forming a low-pressure gas backflow, in addition, the second cryoblock, operating in the heating mode, contains an additional heat exchanger that is switched off during heating, preliminary and deep cooling heat exchangers, filter coalescer and filter separator, expander, filter separator, product gas condensation heat exchanger, filter trap, purge lines an expander, a filter-separator, a condensation heat exchanger for the product gas, a trap filter, as well as a purge gas return flow line, located in a mirror-like arrangement relative to the cryoblock equipment operating in cooling mode, while the cryoblock at the inlet is connected to the warm gas purge flow line with the possibility of using the heat obtained during the heat exchange of the outlet flow of the cold purge gas with the high pressure gas flow in the additional heat exchanger of the cryoblock operating in the cooling mode.

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