RU2744415C1 - Complex for processing main natural gas into marketable products - Google Patents

Abstract

FIELD: gas industry.SUBSTANCE: invention can be used in the gas industry in the context of its intensive development. The invention relates to a complex for processing the main natural gas into commercial products, including a pipeline branch of the main natural gas supply for processing 100; gas processing unit 200, which produces commercial natural gas, fully prepared for liquefaction, ethane fraction, products of separation of a wide light hydrocarbon fraction (hereinafter WLHF) in the form of a propane fraction, a butane fraction, a pentane-hexane fraction (hereinafter PHF). The complex also includes a pipeline for supplying commercial natural gas to the main gas pipeline 300; liquefied natural gas (hereinafter LNG) 400 unit; storage unit for commercial products 500; block for the shipment of commercial products 600; united by direct and feedback links in the form of pipelines, while between the links of the blocks one or more of the additional links are provided.EFFECT: selection of valuable components from the main natural gas in the form of marketable products or raw materials of gas chemical industries, increased efficiency due to the use of material flows of individual links and a decreased anthropogenic load on the environment.4 cl, 1 dwg, 3 tbl, 4 ex

Description

The complex for processing main natural gas into marketable products can be used in the gas industry in the context of its intensive development.

Gas processing enterprises are large-scale, providing the capacity for raw natural gas up to several billion nm ³ / year (several million tons / year). However, in the context of the intensive development of the gas industry, the volumes of natural gas production increase sharply precisely in those regions where there are no additional technical and human resources. So, for example, in Eastern Siberia and the Far East in 2010, only 33 billion nm ³ / year of natural gas was produced, of which only 65% was processed, and the remaining 35% were injected back into the reservoir or flared. According to the long-term plans for the development of these regions, production in them by 2030 should increase to 200 billion nm ³ / year. The construction of gas trunklines several thousand kilometers long (for example, the Power of Siberia gas pipeline is about 4,000 km long) will lead to the development of industry and infrastructure in the regions through which this gas pipeline will be laid. Therefore, in these regions, it is advisable to build enterprises that process the part of the main natural gas necessary for the region with the selection of valuable components from it in the form of marketable products or raw materials of gas chemical industries.

Known installation for processing hydrocarbon gas, containing a gas cooling unit and the release of unstable condensate with the outlet of the prepared gas, a unit for the selection of a wide fraction of light hydrocarbons (hereinafter NGL), including a rectification column with a heater in the lower part, equipped with NGL and gas outlets, NGL output from the rectification column connected to the consumer's facility and / or technological process objects, a booster compressor station, shut-off and / or shut-off and control valves, while the unit is equipped with an additional rectification column that ensures the quality of commercial products - automotive propane or automotive propane-butane, as well as aviation condensed fuel , the inlet of raw materials of which is connected to the outlet of NGL from the distillation column of the NGL separation unit, the additional rectification column is equipped with a bottom heater and an irrigation unit for its top connected to the outlet of the gas phase of this column, and the irrigation unit has the output of commercial products - automobile propane or automobile propane-butane, and the bottom of the additional rectification column and / or the heater have a commercial output - aviation condensed fuel (utility model patent RU 116980, IPC F26J 3/02, filed on 01/11/2012, published on June 10, 2012). The disadvantages of the utility model are:

- a limited range of marketable fuel products (propane for automobiles or propane-butane for automobiles and aviation condensed fuel);

- hardware design of the installation of two blocks, which does not allow obtaining high quality end products due to the content of hydrogen sulfide, organosulfur components, water and other impurities;

- low quality and difficulty of using the generated aviation condensed fuel, which can be limitedly used for helicopter technology (fuel for gasoline aircraft engines must boil off within 40-180 ° C according to GOST 1012-2013, and for jet engines - 60-280 ° C according to GOST 10227-2013), since aviation condensed fuel, due to its lightweight fractional composition, must be stored, transported and supplied to the tanks of aviation equipment under a pressure of 0.5-1.2 MPa.

Known installation for processing raw natural gas, containing interconnected unit of primary separation of raw natural gas, a unit for extracting hydrogen sulfide with an absorbent with selective selectivity for hydrogen sulfide and a supersonic separation unit installed with the possibility of receiving carbon dioxide and purified natural gas at the outlet, with the first input of the unit extraction of H ₂ S is connected to the first outlet of the primary separation unit, the second outlet of which serves to output water with mechanical impurities for disposal, the third outlet is connected to the first inlet of the gas condensate stabilization unit, and the inlet is connected to the raw natural gas supply system, the second and third inputs of the block extracting H ₂ S are connected respectively to the condensate stabilization unit and a sulfur degassing unit, and outputs this block associated with the block sulfur recovery using the Claus process and the block supersonic separation output of said unit is connected to the second input of the condensate stabilization unit, with a The possibility of obtaining stable condensate at the outlet, while the output of the NGL stabilization unit is connected to the NGL fractionation unit, and the sulfur recovery unit using the Claus process is connected with its first and second outputs to the sulfur granulation unit, respectively, through the sulfur degassing unit and through the fine waste gas purification unit from hydrogen sulfide (patent for invention RU 2576738, IPC F25J 3/08, declared on November 14, 2014, published on 03/10/2016). The disadvantages of the invention are:

- condensation of carbon dioxide and its separation from gaseous methane in a supersonic separator at a temperature of minus 70 ° C and a pressure drop of up to 4 MPa, which are more energy-consuming compared to other methods of removing carbon dioxide from natural gas, for example, by absorption purification;

- loss of valuable raw materials for gas chemical industries due to the content in commercial (purified) natural gas up to 12% mol. hydrocarbons C ₂ -C ₄ ;

- extraction of heavy hydrocarbons from natural gas, limited to the production of stable condensate, that is, NGL, which narrows the range of produced marketable products.

The layout of a gas processing complex is known, consisting of one or more stages, each of which includes technological links and general plant facilities, supplemented by a link of the central technological overpass, which is the same for each stage, connecting link and interlink pipelines, and a link of interdepartmental overpasses connecting the queues and objects of the general plant. farms, while in each turn the technological links are sequentially connected to both sides of the link of the central technological overpass, divided into four sections, which, in conjunction with the corresponding technological links, form production zones, and the technological links supply resources from general plant purposes using a link of interdepartmental overpasses through the link central technological overpass (patent for invention RU 2722255, IPC F25J 3/00, filed on 06/08/2019, published on 25/05/2020). The main disadvantage of the invention is the unaccounted potential for using the internal material flows of individual links of the gas processing complex to improve the efficiency of its operation.

Closest to the claimed invention is a complex for processing natural hydrocarbon gas into commercial products, consisting of a gas processing unit A, which produces methane, ethane, propane, butane and pentane-hexane fractions; natural gas liquefaction unit B prepared at gas processing unit A; gas-chemical unit B, which produces polymer products from ethane and / or propane fraction and / or other hydrocarbon feedstock separated at gas processing unit A; logistic block G, including a tank farm for storing marketable products of the above blocks; off-site facilities D, providing energy resources and the necessary reagents to all the above blocks of the complex; providing for energy and technological interconnections between the links of the off-site economy D and the links of the remaining blocks of the complex A, B, C, D with the possibility of both variable execution of the links of these blocks, and their addition with new links (patent for invention RU 2715838, IPC B01D 53/00, declared 01.10.2019, published 03.03.2020). The main disadvantage of the invention is the unaccounted potential for using the internal material flows of individual links of the gas processing complex to improve the efficiency of its operation.

The objective of the claimed invention is to develop a complex for the processing of main natural gas, providing for the selection of valuable components from it in the form of commercial products or raw materials for gas chemical production, increased efficiency due to the use of material flows of individual links and reducing the anthropogenic load on the environment.

The task is solved due to the fact that the complex for the processing of main natural gas into commercial products includes:

- pipeline branch of the main natural gas supply for processing 100;

- gas processing unit 200, which produces commercial natural gas fully prepared for liquefaction, ethane fraction, NGL separation products in the form of propane fraction, butane fraction, pentane-hexane fraction (hereinafter PGF);

- pipeline for supplying commercial natural gas to the main gas pipeline 300;

- block of production of liquefied natural gas (hereinafter LNG) 400;

- storage unit for commercial products 500;

- block for shipment of commercial products 600;

combined by direct and feedback in the form of pipelines, while the composition of the specified gas processing unit 200 includes the following links:

- link for measuring and accounting of raw natural gas 201;

- link of absorption cleaning from acidic components and methanol 202;

- link of deep adsorption drying and mercury removal 203;

- link for rectification extraction of ethane fraction and NGL 204;

- Compression link 205;

- chill-down link 206;

- link for metering and accounting of commercial natural gas 207;

- link for cleaning and fractionation of NGL 208;

- link for metering and accounting of dry natural gas, ethane and propane fractions supplied to the gas chemical production facility 209;

- link for preparation of low pressure fuel gas 210;

- a link for processing recoverable impurities 211;

- a link for preparing a solution of absorbent 212;

- link for preparation of demineralized water 213;

- nitrogen production link 214;

- high pressure fuel gas preparation link 215;

This LNG 400 production unit includes the following links:

- liquefaction link 401;

- link for preparation and compression of refrigerant 402;

the structure of the specified storage unit for commercial products 500 includes the following links:

- LNG storage link 501;

- link for compression of boil-off gas 502;

- a link for the storage of liquefied petroleum gas (hereinafter referred to as LPG) and PGF under pressure of 503;

- link for chilling and thermostating SUG 504;

- link of isothermal storage of LPG 505;

- link for preparation of low pressure fuel gas 506;

the structure of the specified block for the shipment of commercial products 600 includes the following links:

- LNG shipping link 601;

- link of shipment of LPG 602;

- shipping link PGF 603;

between the links of the blocks one or more of the following additional links are provided:

a) feeding the regeneration waste gas from the link 203 to the link 202 using a compressor for mixing with the raw natural gas before the absorber of the link 202 with incomplete extraction of methanol from the raw natural gas in the link 202 with additional purification of purified natural gas in the link 203 or with purified natural gas after the absorber of the link 202 during deep purification of raw natural gas from methanol in the link 202 without additional treatment in the link 203;

b) supplying the expanser gas from the link 202 to the link 210 for use as a fuel gas or to the link 211 for thermal and / or catalytic oxidation with the subsequent disposal of the resulting products;

c) the supply of water extracted from the regeneration waste gas when it is cooled and / or extracted on coalescer filters from the purified natural gas in front of the adsorbers, from the link 203 to the link 202 to the loop of the aqueous absorbent solution or to the acidic water loop or to the link 211 for thermal oxidation at high methanol content;

d) supplying acid gases from the reflux vessel of the stripper of unit 202 to unit 211 for thermal and / or catalytic oxidation or to unit 205 or 402 for mixing with turbine flue gases;

e) partial or complete supply of acidic water from the reflux vessel of the stripper of unit 202 to unit 211 for thermal and / or catalytic oxidation;

f) supplying water after it has been stripped from methanol from link 211 to link 202 into the loop of the aqueous absorbent solution;

g) supply of dry natural gas from link 204 to link 209 for subsequent use as raw material and / or fuel gas for gas chemical production;

h) supplying the ethane fraction from unit 204 to unit 402 to feed the ethane refrigerant circuit and / or the mixed refrigerant circuit or circuits and / or to the unit 401 to control the calorific value of the LNG;

i) partial or complete supply of the ethane fraction from unit 204 to unit 504 with an excess of ethane fraction produced at the gas processing unit 200;

j) supply of ethane fraction from unit 204 to unit 205 for mixing with dry natural gas with a decrease or absence of ethane fraction consumption in gas chemical production;

k) supplying propane refrigerant from unit 206 to unit 204 for condensing vapors from the deethanizer column and / or cooling the dried natural gas and / or cooling the dry natural gas recycle;

l) supply of propane refrigerant from link 206 to link 205 for cooling compressed natural gas from the discharge of the compressors after air coolers (hereinafter AVO);

m) supplying compressed natural gas from link 205 after the first compression stage before or after AVO to link 208 for use as regeneration gas and / or refrigeration gas;

o) supplying dry natural gas from link 204 or compressed natural gas from the compressor discharge of link 205 to link 402 to feed the mixed refrigerant circuit or circuits;

o) supplying the regeneration waste gas and / or cooling gas from the link 208 to the link 210 for use as a fuel gas, and / or to the link 211 for thermal and / or catalytic oxidation, and / or to the link 207 for mixing with commercial natural gas , and / or link 205 or 402 for mixing with turbine flue gases;

p) supplying stripping gas from unit 502 to unit 402 for use as a gas turbine fuel and / or to unit 215 for use as a primary source of high pressure fuel gas;

c) supplying raw natural gas from link 201 and / or compressed natural gas from the first compressor stage of link 205 to link 215 for use as a high pressure fuel gas make-up when the amount of stripping gas from link 502 is insufficient;

r) supplying dry natural gas from link 204 to link 210 for use as the primary source of low pressure fuel gas;

s) supplying raw natural gas from link 201 and / or compressed natural gas from the discharge of the compressors of link 205 to link 210 for use as a low pressure fuel gas make-up when the amount of dry natural gas from link 204 is insufficient;

t) feeding the propane fraction from the link 208 and / or from the link 503 to the link 401 to regulate the calorific value of LNG, and / or to the link 402 to feed the mixed refrigerant circuit or circuits, and / or to the link 206 to fill and feed the propane refrigerant circuit ;

x) feeding the butane cut from unit 208 to unit 402 to feed the mixed refrigerant circuit or circuits;

v) supply of propane and / or butane and / or pentane-hexane fractions from unit 503 to unit 207 for mixing with commercial natural gas with a periodic decrease or absence of consumption or during the production of substandard LPG and / or PGF;

h) feeding hydrocarbon condensate from link 202 to link 503 for mixing with PGF.

The additional link according to item a allows the use of the waste gas of the adsorbent regeneration to extract the ethane fraction and NGL, increasing their production, instead of burning this gas as a fuel gas and / or flaring with environmental pollution.

The additional connection according to item b allows the use of expanser gas, separated from an aqueous solution of an absorbent and consisting mainly of hydrocarbons, as a fuel gas, reducing the consumption of dry natural gas consumed for fuel needs.

The additional connection according to claim c allows the use of water recovered from the regeneration waste gas and / or purified natural gas, instead of discharging it into the wastewater system, thereby reducing the load on the wastewater treatment system.

Additional connection according to item d allows, due to the technological use of acid gases from the reflux vessel of the stripper, to eliminate environmental pollution by mercaptans, hydrogen sulfide and methanol.

Additional connection according to item e allows partially or completely removing acidic water in the form of a water-methanol mixture in cases where methanol accumulates in the upper part of the stripper, which can lead to foaming of the absorbent solution and disruption of the normal modes of regeneration of the solution in the stripper and purification of raw natural gas in the absorber. Additionally, this relationship allows you to maintain the efficiency of methanol removal with an increase in its concentration in the natural gas feed or increase the depth of purification from methanol with its constant concentration in the natural gas feed.

Additional connection according to item e allows to reduce the production of fresh demineralized water for replenishment of the aqueous absorbent solution while maintaining the required concentration.

Additional communication according to clause h, and / or according to clause, and / or according to clause k provides variability in the operation of the complex for processing main natural gas into commercial products and allows, depending on the technological need, to use the ethane fraction, respectively, as a refrigerant for feeding the refrigerant circuit or circuits, and / or for regulating the calorific value of LNG (item h), and / or as a component of dry natural gas (item c) (according to the standards, the maximum ethane content in commercial natural gas is permissible at the level of 7-8 % molar) and / or send to unit 504 (p. i) for accumulation and shipment to consumers with a decrease or absence of ethane fraction consumption at the gas chemical production, so as not to stop the ethane fraction production at the gas processing unit 200.

Additional connection on p. L and / or p. M allows the generated propane fraction to be used as a propane refrigerant for condensation of vapors of the deethanizer column, and / or cooling of dried natural gas, and / or cooling of the dry natural gas recycle (p. L), and / or for cooling compressed natural gas after AVO (lm), maintaining a stable operating mode of the deethanizer column and / or a constant temperature of commercial natural gas regardless of the ambient temperature, respectively, and at the same time ensuring the variability of the operation of the gas processing unit 200.

Additional communication according to p.n. and / or p.o allows the use of compressed and / or dry natural gas both as a regeneration gas and / or gas for cooling the adsorbent (p.n.) and as a refrigerant for feeding the circuit or mixed refrigerant circuits (p. o), which provides technological flexibility and variability of the gas processing unit 200.

Additional communication on p. P allows the use of boil-off gas as fuel, reducing the power of boil-off gas compression due to the lower pressure of the fuel network.

The additional connection according to claim c allows the use of raw and / or compressed natural gas for feeding high-pressure fuel gas with a lack or absence of boil-off gas, providing technological flexibility and variability in the operation of the gas processing unit 200.

Additional communication on the item t allows the use of dry natural gas as the main source of low-pressure fuel gas, which ensures the operation of the complex and reduces the loss of valuable hydrocarbons relative to the use of raw natural gas as a fuel gas.

The additional connection according to claim y allows, in the event of a shortage of dry natural gas, to use raw natural gas or compressed natural gas as a replenishment of low-pressure fuel gas, providing technological flexibility and variability in the operation of the gas processing unit 200.

Additional communication according to claim f and / or according to claim x allows the generated propane fraction and / or butane fraction to be used, respectively, to feed the mixed refrigerant circuit or circuits, providing technological flexibility and variability in the operation of the gas processing unit 200 and the LNG 400 production unit.

An additional connection on p. C allows mixing propane and / or butane and / or pentane-hexane fractions with commercial natural gas with a periodic decrease or absence of their consumption due to the peculiarities of logistics or the production of substandard LPG and / or PGF.

It is advisable to supplement unit 200 with a unit for producing elemental sulfur 216 using the Claus method and supplying acid gases from the reflux tank of the desorber unit 202 with a high concentration of hydrogen sulfide in the main natural gas.

It is expedient to supplement unit 200 with an acid gas compression unit 217 for supplying acid gases from the reflux tank of the desorber unit 202 for mixing with commercial natural gas before unit 207 after withdrawing a part of the commercial natural gas, fully prepared to reduce greenhouse gas emissions at a low concentration of hydrogen sulfide in the raw natural gas. for liquefaction, link 401 and / or for the production of methanol and / or urea and / or other products.

It is advisable for a high concentration of mercaptans in the regeneration exhaust gas of the link 208 and / or a low consumption of low-pressure fuel gas to supplement the unit 200 with a regeneration gas purification link 218 to extract mercaptans and / or methanol from the regeneration waste gas of the link 208 with the supply of purified regeneration gas from the link 218 link 210 as fuel gas and / or link 205 for mixing with dry natural gas or link 207 for mixing with commercial natural gas.

The indicated additional links, which are material flows between various links of the complex for the processing of main natural gas into marketable products, are applicable to the following link configurations.

The link for measuring and accounting for raw natural gas 201 is a set of control and measuring and analytical devices that allow, with the required accuracy, to measure and account for natural gas supplied as raw natural gas for processing of main natural gas, as well as to determine its composition and physicochemical properties.

The link of absorption purification from acidic components and methanol 202 is realized in the form of a two-column system for removing acidic components (carbon dioxide and hydrogen sulfide) and methanol from raw natural gas. The purification of raw natural gas is carried out by flushing it with an aqueous solution of an absorbent, activated if necessary with additional components, in the first column (absorber) with a pressure slightly lower than the pressure of the main natural gas entering for processing in the range of 5.0-9.8 MPa (g), and the temperature of the regenerated absorbent solution supplied to the upper part of the absorber is maintained in the range of 30-50 ° C. Regeneration of the saturated solution of the absorbent is carried out in the second column (desorber), where the pressure is maintained within 0.05-0.1 MPa (g), and the release of the acidic components and methanol absorbed in the absorber is carried out by supplying heat to the cube of the desorber with water vapor or heat transfer oil. The saturated solution of the absorbent from the absorber to the stripper is fed through an expanser vessel, where the pressure is maintained in the range of 0.4-1.0 MPa (g) for the possibility of supplying the expansion gas (expander gas) to the low-pressure fuel network and / or for oxidation for subsequent safe disposal. In the link of absorption cleaning from acidic components and methanol 202, it is also provided for the filtration of a part of the regenerated absorbent solution in the amount of 10-20% of the total circulation volume of the solution in the filter group, which is a sequential coarse filter from mechanical impurities, a carbon filter of adsorption cleaning from decomposition products absorbent and fine filter from coal dust.

In the link of deep adsorption drying and purification from mercury 203, moisture is removed with additional purification from traces of methanol in the first group of adsorbers, where the pressure is maintained in the range of 4.9-9.7 MPa (g), as well as mercury vapor in the second group of adsorbers, where the pressure is maintained in the range of 4.8-9.6 MPa (g). Regeneration and cooling of the adsorbent of the first group of adsorbers (zeolites) is carried out with dried natural gas, the flow rate of which is up to 10% of the flow rate of purified natural gas entering the deep adsorption drying and mercury purification unit 203 at a pressure in the range of 4.8-9.6 MPa ( huts). The regeneration gas is heated in a furnace or in a heat exchanger using steam or heating oil to a temperature in the range of 230-330 ° C. In the second group of adsorbers, sulfur-impregnated activated carbon or inorganic zeolites with the addition of sulfides of various metals are used as the adsorbent. After saturation of this adsorbent with mercury or at the end of the service life of the adsorbent, it is replaced with a fresh one, and the spent adsorbent is sent for disposal.

A two-column system for low-temperature separation of dried natural gas with the production of cold due to the expansion of a part of this gas on an expander is implemented in the unit of the rectification extraction of the ethane fraction and NGL 204. Another part of the dried natural gas is cooled and condensed in a recuperative heat exchanger, and after throttling is sent as reflux to the first distillation column (demethanizer), where the pressure is maintained in the range of 1.0-3.0 MPa (g). The separation products of dried natural gas in a demethanizer column are dry natural gas and a C ₂ and higher fraction. To increase the degree of extraction of the ethane fraction, a part of dry natural gas in an amount of 5-40% is compressed on a separate compressor or on the compressors of the compression unit 205, then condensed in a recuperative heat exchanger and, after throttling, is fed as additional reflux to the demethanizer column. In the second distillation column (deethanizer), the fraction C ₂ and higher is separated to obtain an ethane fraction and NGL. To enable the beneficial use of the ethane fraction during the period when it is not consumed in the gas chemical production, the pressure in the deethanizer column is maintained equal to or higher than the pressure in the demethanizer column for supplying the ethane fraction to the compression unit 205.

Compression unit 205 is designed to compress dry natural gas coming from the fractionation recovery unit of ethane fraction and NGL 204 before it is fed to the main gas pipeline or to the LNG production unit 400. Dry natural gas is compressed in one or two stages, depending on the required discharge pressure on the compressors with gas turbine and / or electric drive, cooling on AVO after each compression stage. When using a gas turbine drive, heat recovery from turbine flue gases with the generation of water vapor and / or for heating the heat carrier oil is provided.

Cooling link 206 is a closed loop of propane refrigerant, where it is sequentially compressed to a pressure in the range of 1.2-1.7 MPa (g) due to a compressor with an electric drive and / or a gas turbine drive, cooling and condensation at the AVO, supply to consumers due to the compression pressure in the compressor or by means of pumps, throttling on the Joule-Thompson valve to the set pressure value with the temperature corresponding to the equilibrium state, boiling of the liquid refrigerant in the evaporators at a constant temperature and the return of refrigerant vapors to the compressor intake.

The link for measuring and accounting for commercial natural gas 207 is a set of control and measuring and analytical instruments that allow with the required accuracy to measure and record the commercial natural gas supplied to the main gas pipeline, as well as to determine its composition and physicochemical properties.

In the NGL purification and fractionation unit 208, first, mercaptans and / or methanol on zeolites recovered with compressed natural gas from the compression unit 205 after heating it in a furnace or in a heat exchanger using steam or heat transfer oil are first removed from NGL. Compressed natural gas from compression unit 205 or high-quality nitrogen from nitrogen production unit 214 is used as the adsorbent cooling gas. Purified NGL is separated into propane, butane and pentane-hexane fractions in two distillation columns for sequential recovery of propane and butane fractions or pentane-hexane and butane fractions.

The link for measuring and accounting for dry natural gas, ethane and propane fractions supplied to the gas chemical production plant 209 is a set of control and measuring and analytical instruments that allow measuring and accounting with the required accuracy of dry natural gas and ethane fraction supplied to the gas chemical production plant from the fractionation extraction of ethane fraction. fraction and NGL 204, propane fraction from the unit of purification and fractionation of NGL 208, as well as to determine their composition and physicochemical properties.

In the low-pressure fuel gas preparation unit 210, the fuel gas is heated in series to avoid low temperatures after expansion (throttling) to a pressure of 0.8-1.0 MPa (g), as well as separation and filtration. The separation equipment simultaneously creates the necessary buffer to prevent abrupt changes in the fuel gas composition. During normal operation, the main source of low-pressure fuel gas is dry natural gas from the ethane fraction and NGL 204. It is also envisaged to supply raw natural gas from the metering and metering unit of raw natural gas 201 and compressed natural gas from the compression unit 205 as backup sources ... The low pressure fuel gas prepared in the unit 210 is used for the needs of the units of the gas processing unit 200.

The unit for processing the extracted impurities 211 is a group of devices: thermal and / or catalytic oxidizers designed for the oxidation of sulfur-containing compounds and / or methanol with air oxygen, supplied as part of the material flows of individual units. The configuration of oxidizers is provided without and / or with heat recovery from flue gases with the possibility of generating steam and / or heating the heating oil and / or heating water. For the case of a high content of methanol in the composition of the main natural gas entering the complex, a rectification column for stripping sour water is provided in the unit for processing the extracted impurities 211. The upper product of the separation of the column will be methanol of high concentration, and the bottom product will be water stripped from methanol, returned to the process (to the link of absorption purification from acidic components and methanol 202 to the loop of an aqueous absorbent solution). High concentration methanol is removed as one of the types of marketable products of the complex or utilized in a thermal and / or catalytic oxidizer.

The link for the preparation of the absorbent solution 212 is designed to receive reagents (fresh absorbent and demineralized water), prepare an aqueous solution of the absorbent of the required concentration and then supply the finished solution to the loop of the aqueous solution of the absorbent of the link for absorption cleaning from acidic components and methanol 202 in order to fill the system or make up the solution, and also for receiving an absorbent solution when emptying the equipment of the absorption treatment unit from acidic components and methanol 202.

In the link for the preparation of demineralized water 213, reverse osmosis and / or electrodialysis technologies are used. A buffer storage tank and pumps for supplying demineralized water to consumers are also provided.

Nitrogen production unit 214 produces high and low quality nitrogen. Low quality nitrogen is produced by membrane or adsorption method (PSA) and sent to consumers through a buffer tank. High-quality nitrogen is produced by low-temperature rectification or evaporation and heating to the required temperature of imported liquid nitrogen from the side with supply to consumers through a buffer tank.

In the high-pressure fuel gas preparation unit 215, there are sequential throttling of the fuel gas to a pressure of 3.5-3.6 MPa (g), separation and filtration. The separation equipment simultaneously creates the necessary buffer to prevent abrupt changes in the fuel gas composition. During normal operation, the main source of high-pressure fuel gas is excess boil-off gas from the boil-off gas compression unit 502 of the commercial product storage unit 500, unclaimed in the refrigerant preparation and compression unit 402 of the LNG 400 production unit. compressor stages of the compression unit 205 and / or raw natural gas from the unit of metering and metering of raw natural gas 201, which is heated at the inlet to the heat exchanger or electric heater before or after throttling to prevent the formation of gas hydrates.

Elemental sulfur unit 216 uses the Claus method. First, the acid gas is burned, and the oxygen in the air is supplied to the furnace in the amount necessary for the oxidation of hydrogen sulfide to sulfur. For this, reactors are used, consisting of a combustion chamber and a tubular heat exchanger. Burners are located in the end part of the combustion chamber. In the zone of mixing hydrogen sulfide and air, combustion occurs in a swirling flow, then the combustion products enter the main combustion chamber. Further, the combustion products are cooled with water, passing through the tube space of the tubular heat exchanger, and enter the condenser, from where the resulting sulfur is removed to the storage and degassed. Commercial products can be shipped in the form of lumpy, powder, granular or liquid sulfur.

Sour gas compression link 217 is intended for supplying low-pressure acid gases from the absorption purification link from acid components and methanol 202 for mixing with commercial natural gas before measuring and metering commercial natural gas 207 after diverting a part of commercial natural gas, completely prepared for liquefaction, to the link liquefaction 401 and / or for the production of methanol and / or urea and / or other products. In the acid gas compression link 217, single-stage or multi-stage compression in compressors with an electric motor and / or a gas turbine drive and cooling by means of AVO are sequentially implemented. When using a gas turbine drive, heat recovery from turbine flue gases with the generation of water vapor and / or for heating the heat carrier oil is provided. In the case of supplying acid gases to the production of methanol and / or urea and / or other products as part of the acid gas compression unit 217, additional equipment may be provided for cleaning gases from unwanted impurities.

Regeneration gas purification unit 218 is designed to remove mercaptans and / or methanol from regeneration waste gas coming from the NGL 208 purification and fractionation unit using an adsorbent. The purified regeneration gas is used to cover the needs of the complex for the processing of main natural gas into commercial products, for example, it is fed to the low-pressure fuel gas preparation unit 210, or for mixing with commercial natural gas before the metering and metering unit of commercial natural gas 207, or to the compression unit 205. A high purity nitrogen stream from the nitrogen production unit 214 is used after heating to the required temperature to regenerate the impurity-saturated adsorbent of the regeneration gas purification unit 218. Nitrogen saturated with recoverable impurities is fed for thermal and / or catalytic oxidation to a unit for processing recoverable impurities 211 in order to utilize mercaptans and / or methanol. A high purity nitrogen stream is also used to cool the regenerated adsorbent.

Liquefaction unit 401 implements the processes of sequential cooling, liquefaction of commercial natural gas, fully prepared for liquefaction and pre-mixed with propane and / or ethane fraction, if necessary, and LNG subcooling. These processes are carried out in separate cryogenic heat exchangers and / or in different sections of one cryogenic heat exchanger. The supercooled LNG is sent to LNG storage link 501 of Commercial Product Storage Unit 500.

The refrigerant preparation and compression unit 402 is a closed loop or closed loops of mixed refrigerants containing nitrogen and / or methane and / or ethane or ethylene and / or propane and / or various forms of butanes. Each circuit is sequentially compressed in a compressor with an electric drive and / or a gas turbine drive, cooling and / or condensation in an AVO, subcooling in cryogenic heat exchangers, throttling on a valve and / or an expander, and supply of a liquefaction unit 401 to the cryogenic heat exchanger as a refrigerant. In the cryogenic heat exchanger of the liquefaction unit 401, refrigerant is evaporated and the refrigerant vapor is subsequently returned to the compressor intake. In the case of using gas turbines, it is envisaged to recover the heat of flue gases with the generation of water vapor and / or heating the heat carrier oil.

LNG storage unit 501 is designed to store and accumulate a ship's LNG batch in one or more tanks.

The stripping gas compression unit 502 receives stripping gas generated during throttling or expansion on the LNG liquid expander in front of the storage tank, during the storage of LNG in the LNG storage unit 501 and when loading LNG into LNG carriers from the LNG shipping unit 601 of the commercial product shipping unit 600 , for its subsequent supply as fuel gas of the turbines of the circuit or mixed refrigerant circuits of the unit for preparation and compression of refrigerant 402 of the LNG 400 production unit and / or as fuel gas of the turbines of the compression unit 205 of the gas processing unit 200.

At the level of storage of LPG and PGF under pressure 503, storage of commercial products in the form of LPG (propane and butane fractions) and PGF is carried out in one or more pressure tanks.

The unit for cooling down and thermostating of LPG 504 is intended for cooling down and condensation of incoming propane and butane fractions, as well as condensation of LPG stripping gases formed in the unit for isothermal storage of LPG 505 and during the shipment of LPG in the unit for shipping LPG 602 of the unit 600 for shipment of commercial products.

The link of isothermal storage of LPG 505 is intended for isothermal storage and accumulation of a ship's batch of LPG in one or several tanks.

The low pressure fuel gas obtained in the low pressure fuel gas preparation unit 506 is used for the needs of the units of the block 500.

The LNG, LPG and PGF shipping links 601, 602 and 603, respectively, are intended for shipment of marketable products to consumers and return to the complex of the boil-off gases generated during shipment.

The drawing shows a schematic diagram of one of the possible options for the implementation of a complex for processing main natural gas into commercial products using the following designations:

1-79 - pipelines;

100 - pipeline branch of the main natural gas supply for processing;

200 - gas processing unit;

201 - link for measuring and metering raw natural gas;

202 - link of absorption purification from acidic components and methanol;

203 - a link of deep adsorption drying and mercury removal;

204 - link for rectification extraction of ethane fraction and NGL;

205 - compression link;

206 - chill-down link;

207 - link for metering and accounting of commercial natural gas;

208 - NGL purification and fractionation unit;

209 - link for measuring and accounting for dry natural gas, ethane and propane fractions supplied to the gas chemical production;

210 - link for preparation of low pressure fuel gas;

211 — link for processing the extracted impurities;

212 — link for preparation of absorbent solution;

213 - link for preparation of demineralized water;

214 - nitrogen production link;

215 - high pressure fuel gas preparation link;

300 - pipeline for supplying commercial natural gas to the main gas pipeline;

400 - LNG production unit;

401 - liquefaction link;

402 - refrigerant preparation and compression link;

500 - storage unit for commercial products;

501 - LNG storage link;

502 - boil-off gas compression link;

503 - link for storage of LPG and PGF under pressure;

504 - link for chilling and thermostating of LPG;

505 - link for isothermal storage of LPG;

506 - low pressure fuel gas preparation link;

600 - block for shipment of marketable products;

601 - LNG shipping link;

602 - LPG shipment link;

603 - PGF shipment link.

The complex for processing main natural gas into marketable products according to the presented schematic diagram operates as follows. Main natural gas from the pipeline branch of the main natural gas supply for processing 100 through pipeline 1 is supplied as raw natural gas to the metering and metering link of raw natural gas 201 of the gas processing unit 200. At start-up and in the event of a shortage of fuel gas of low and / or high pressure part of the natural gas feed is directed to the low pressure fuel gas preparation unit 210 and / or to the high pressure fuel gas preparation unit 215 via pipelines 9 and / or 10, respectively. The main amount of raw natural gas through pipeline 2, after metering and metering, is sent to the link of absorption purification from acidic components and methanol 202, where carbon dioxide, hydrogen sulfide and methanol are removed with the help of an aqueous absorbent solution. The purified natural gas is directed through pipeline 3 to the link of deep adsorption drying and purification from mercury 203. The expander gas separated from the saturated absorbent solution is removed through pipelines 16 and 17 to the link for processing the extracted impurities 211 and to the link for the preparation of low-pressure fuel gas 210, respectively, for use as fuel gas. The recovered sour gases (carbon dioxide and hydrogen sulfide) are fed through the pipeline 18 to the unit for processing the extracted impurities 211. The acidic water in the form of a water-methanol mixture is sent through the pipeline 75 to the unit for processing the extracted impurities 211 for stripping methanol from it, after which the purified water is returned through the pipeline 76 into the loop of the aqueous solution of the absorbent of the unit of absorption purification from acidic components and methanol 202.

To feed the loop of the aqueous solution of the absorbent of the unit of absorption cleaning from acidic components and methanol 202, the supply of the absorbent is provided through the pipeline 49 from the unit for preparing the solution of the absorbent 212. To supply water to the unit of absorption cleaning from acidic components and methanol 202 and the unit for preparing the solution of the absorbent 212, the supply of demineralized water is provided from the link for the preparation of demineralized water 213 through pipelines 74 and 79, respectively.

In the link of deep adsorption drying and purification from mercury 203, the purified natural gas supplied through pipeline 3 is dried and cleaned of mercury, after which the dried natural gas is sent through pipeline 4 to the link for the fractionation of ethane fraction and NGL 204. Part of the dried natural gas is used in the deep link adsorption drying and mercury removal 203 as a regeneration gas and / or a gas for cooling the desiccant adsorbents, after which the regeneration waste gas is pre-compressed in the deep adsorption drying and mercury removal link 203 and is directed through the pipeline 19 to the absorption cleaning link from acid components and methanol 202 for mixing with raw natural gas for repeated purification in order to exclude the accumulation of undesirable impurities in the link of deep adsorption drying and purification from mercury 203. Water extracted from the regeneration waste gas when it is cooled and / or on coalescer filters from the purified natural gas before the adsorption by taking in the unit of deep adsorption drying and purification from mercury 203, through pipelines 77 and / or 78 it enters the unit of absorption purification from acidic components and methanol 202 and / or to the unit for processing the extracted impurities 211, respectively.

The dried natural gas supplied through the pipeline 4 in the unit of the rectification extraction of the ethane fraction and NGL 204 is divided into:

- dry natural gas, partly sent through pipeline 11 to the metering and metering link of dry natural gas, ethane and propane fractions 209 supplied to the gas chemical production facility for further flow through pipeline 13 directly to the gas chemical production as raw material and / or fuel gas, partly directed through a pipeline 12 to a low pressure fuel gas preparation unit 210, and partially directed through a pipeline 5 to a compression unit 205;

- ethane fraction, partially sent through pipeline 43 to the metering and metering unit supplied to the gas chemical production of dry natural gas, ethane and propane fractions 209 for further flow through pipeline 44 directly to the gas chemical production as a raw material, partially sent through pipeline 47 to the preparation unit and compressing refrigerant 402 of the LNG 400 production unit for feeding the ethane refrigerant circuit and / or the mixed refrigerant circuit or circuits, also in the absence of demand from the gas chemical production or when an excess of ethane fraction is generated, the latter can be sent through pipeline 45 to the cooling and thermostating link of LPG 504 of the storage unit commercial product 500 and / or through pipeline 46 to compression unit 205;

- NGL, directed through pipeline 20 to the NGL treatment and fractionation unit 208.

For the operation of the unit of rectification extraction of the ethane fraction and NGL 204, propane refrigerant is used, supplied through the pipeline 51 from the chill unit 206 and returning through the pipeline 50 after the cold transfer.

The dry natural gas supplied through the pipeline 5 to the compression unit 205 is compressed, cooled by the AVO and, if necessary, with the propane refrigerant supplied through the pipeline 53 from the cooling unit 206 and returned through the pipeline 52 after the cold transfer. Fuel gas is supplied to the compression unit 205 and the chill-down unit 206 via pipeline 59 and pipeline 61, respectively, from the high-pressure fuel gas preparation unit 215. Part of the compressed natural gas, before being cooled with the propane refrigerant, is supplied through pipeline 48 for use as regeneration gas and / or gas for cooling adsorbents of the NGL cleaning and fractionation unit 208. One part of the commercial natural gas, fully prepared for liquefaction, is sent through pipeline 8 to the gas liquefaction unit 401 of the LNG 400 production unit, and the other part via pipeline 6 to the unit for measuring and metering of commercial natural gas 207 , from where, via pipeline 7, through the pipeline for supplying commercial natural gas to the main gas pipeline 300, it is supplied to the main gas pipeline. It is also possible to supply a part of the compressed natural gas through the pipeline 14 to the low pressure fuel gas preparation unit 210 and / or through the pipeline 60 to the high pressure fuel gas preparation unit 215 for use as fuel gas, and / or through the pipeline 15 to the preparation and compression unit refrigerant 402 of the LNG production unit 400 for feeding the mixed refrigerant circuit or circuits, as well as as a backup source of fuel gas when it is insufficient.

Commodity natural gas supplied through pipeline 8 to the liquefaction link 401 of the LNG production unit 400, fully prepared for liquefaction, is cooled and condensed due to the use of refrigerants coming through the group of pipelines 57 from the link of preparation and compression of refrigerant 402 and returning through the group of pipelines 58 after the transfer of cold ... Refrigerants of the required composition are produced directly in the section for the preparation and compression of refrigerant 402 by mixing in the required proportions compressed natural gas (component - methane) coming from the compression section 205 via pipeline 15, ethane fraction (component - ethane) coming from the section of rectification extraction of the ethane fraction and NGL 204 through pipeline 47, propane fraction (component - propane) coming from the NGL 208 purification and fractionation unit via line 32, butane fraction (butane component) coming from the NGL 208 purification and fractionation unit via line 42, nitrogen from the nitrogen production unit 214 via pipeline 65. The supercooled LNG obtained in the liquefaction unit 401 is fed through pipeline 54 to the LNG storage unit 501 of the commercial product storage unit 500, where the shiploads of LNG are accumulated. LNG is sent through pipeline 55 to the LNG offloading link 601 of the offloading unit 600 for shipment via pipeline 56 to gas carriers for shipment to consumers. The displacement gases and stripping gases generated during the LNG shipment are fed through the pipeline 72 from the LNG carriers to the LNG offloading link 601, and then through the pipeline 73 they are fed to the boil-off gas compression link 502 of the commercial product storage unit 500. In the boil-off gas compression link 502 according to The line 66 also receives the stripping gases generated in the LNG storage unit 501. The compressed stripping gases from the stripping gas compression unit 502 through the line 63 in the required amount enter the refrigerant preparation and compression unit 402 of the LNG 400 unit as fuel gas. The excess of compressed stripping gases through the pipeline 62 is directed to the high pressure fuel gas preparation unit 215 of the gas processing unit 200.

In the NGL 208 purification and fractionation unit, mercaptans and methanol are removed from the ethane fraction and NGL 204 separated in the fractionation extraction unit and 204 NGL entering the pipeline 20 before separation into:

- propane fraction, partially sent through pipeline 23 to the link for measuring and accounting for dry natural gas, ethane and propane fractions 209 supplied to the gas chemical production facility for further flow through pipeline 24 directly to the gas chemical production as a raw material, partially directed through pipeline 25 for filling and replenishment the propane refrigerant circuit to cool down unit 206, partially directed through line 31 to the liquefaction unit 401 of the LNG production unit 400 to control the calorific value of LNG, partially directed through line 32 to feed the mixed refrigerant circuit or circuits of the refrigerant preparation and compression unit 402 of the LNG unit 400 at the same time, the balance amount of the propane fraction is supplied through pipeline 26 to the LPG and PGF storage unit under pressure 503 of the commercial product storage unit 500;

- butane fraction, partially directed through pipeline 42 for feeding the mixed refrigerant circuit or circuits of the unit for preparation and compression of refrigerant 402 of the 400 LNG production unit, the balance amount of the butane fraction is supplied via pipeline 37 to the LPG and PGF storage unit under pressure 503 of the commercial product storage unit 500;

- PGF, directed through pipeline 33 to the LPG and PGF storage unit under pressure 503 of the storage unit 500 for further supply via pipeline 34 to the PGF shipment unit 603 of the unit 600 of commercial products shipment, where pipeline 35 is used for shipment to railway tanks to consumers , the displacement gases formed in this case through pipeline 70 from railway tanks are supplied to the PGF 603 shipment unit for further supply through the 71 pipeline to the LPG and PGF storage unit under pressure 503 of the commercial product storage unit 500.

Compressed natural gas is used as the regeneration gas and / or the gas for cooling the adsorbents of the NGL cleaning and fractionation unit 208, supplied through the pipeline 48 from the compression unit 205. The regeneration waste gas is sent through the pipeline 21 to the unit for the preparation of low-pressure fuel gas 210 for use as a component fuel gas and / or via line 22 to a treatment unit for recoverable impurities 211 for disposal, respectively.

Propane and butane fractions entering the LPG and PGF storage unit under pressure 503 of the commercial product storage unit 500 through pipelines 26 and 37 are then sent sequentially through pipelines 27 and 38 to the LPG 504 chilling and thermostating unit for subcooling and through pipelines 28 and 39, accordingly, to the link of isothermal storage of LPG 505, where the accumulation of ship lots takes place. When the propane and butane fractions are shipped through pipelines 29 and 40, respectively, they are sent to the LPG 602 shipment unit of the sales unit 600 for shipment through pipelines 30 and 41, respectively, to gas carriers for shipment to consumers. Displacement gases and stripping gases generated during LPG shipment are fed through pipeline 67 from gas carriers to the LPG shipment unit 602, from where they are fed via pipeline 68 to the LPG isothermal storage unit 505 of the commercial product storage unit 500 and then through pipeline 69 enter the chill-down unit and thermostating of SUG 504 for re-condensation.

The commercial product storage unit 500 is supplied with fuel gas from the low pressure fuel gas preparation unit 506, where the fuel gas is supplied through pipeline 36 from the low pressure fuel gas preparation unit 210. Nitrogen for the needs of the commercial product storage unit 500 is supplied through the pipeline 64 from the nitrogen production unit 214 ...

The examples below confirm the effectiveness of a number of proposed solutions of the proposed complex for the processing of main natural gas into commercial products.

Example 1

The supply of acidic water in the form of a water-methanol mixture from the reflux tank of the desorber of the absorption purification unit from acidic components and methanol 202 to the unit for processing the extracted impurities 211 according to p. E for thermal and / or catalytic oxidation of methanol allows partially or completely removing acidic water in cases where there is an accumulation of methanol in the upper part of the stripper, which can lead to foaming of the absorbent solution and disruption of the normal modes of regeneration of the solution in the stripper and purification of raw natural gas in the absorber. Additionally, this relationship allows you to maintain the efficiency of methanol removal with an increase in its concentration in the natural gas feed or increase the depth of purification from methanol with its constant concentration in the natural gas feed.

Table 1 shows a comparison of the degree of purification of raw natural gas from methanol at different proportions of blowdown relative to the consumption of acidic water. According to the presented data, the purging of acidic water makes it possible to reduce the methanol concentration in the purified natural gas by a factor of 3 and bring it to the level of 0.07 ppm _V.

Example 2

The supply of water after stripping methanol from it from the unit for processing the extracted impurities 211 to the unit of absorption purification from acidic components and methanol 202 according to claim e makes it possible to reduce the consumption of fresh demineralized water for feeding the aqueous absorbent solution when part of the acidic water is removed for disposal.

Reduction of the make-up of demineralized water in the link of absorption purification from acidic components and methanol 202 with different proportions of purging acidic water and stripping methanol from it with subsequent return to the part of absorption purification from acidic components and methanol 202 is presented in Table 2. According to the data obtained during purging of acidic water in an amount from 25 to 100%, stripping of methanol from sour water can reduce the supply of demineralized water by 94-98%.

Example 3

Supply of an ethane fraction that meets the quality requirements for use in the refrigerant circuit from the rectification extraction of the ethane fraction and NGL 204 to the refrigerant preparation and compression unit 402 of the LNG 400 production unit according to item 3 for preparation and subsequent make-up of the ethane refrigerant circuit and / or the circuit or mixed refrigerant circuits allows you to exclude an additional separate link for receiving ethane from the side, its preparation, which consists in removing moisture that can get into the product during its transportation, filtration and supply to the refrigerant circuit.

Example 4

Supply of ethane fraction from the section of rectification extraction of ethane fraction and NGL 204 and / or propane fraction from the unit of purification and fractionation of NGL 208 and / or propane fraction from the LPG PGF storage unit under pressure 503 to the liquefaction unit 401 of the LNG 400 production unit according to p. z and f is designed to regulate the caloric content of the resulting LNG. This solution allows expanding the sales markets and, accordingly, the liquidity of LNG, while maintaining a stable operating mode of links 204 and 208 with the maximum recovery of C ₂ components and higher and the production of products with constant quality. Also, while reducing the consumption of ethane and / or propane fractions, the main consumers can supply these components to adjust the composition of the LNG produced within the available range, which additionally increases the functional flexibility of the complex.

As an example, let us consider the operation of a complex for processing main natural gas into commercial products with the degree of ethane extraction from dried natural gas in the rectification unit of ethane fraction and NGL 204 96.5% and LNG production in the liquefaction unit 401 of the LNG 400 production unit with three different solutions to provide calorie content (table 3):

Option 1 - without supply of components that increase the caloric content of LNG;

option 2 - with the supply of an ethane fraction to increase the calorific value of LNG;

Option 3 - with the supply of propane fraction to increase the calorific value of LNG.

As can be seen from Table 3, for option 1 (without the supply of components that increase the calorific value of LNG), the higher calorific value of LNG is 37.7 MJ / stm ³ . To increase the calorific value of the next batch of LNG to 38.6 MJ / stm ³ , both options are possible with the supply of ethane or propane fractions. Obviously, with a sufficient resource of ethane and propane fractions, it is possible to formulate an optimal formulation for compounding LNG for their introduction, ensuring the minimum cost of the produced LNG with a given gross calorific value.

Thus, the claimed invention, which provides for the selection of valuable components from natural gas in the form of commercial products or raw materials of gas chemical industries, increases efficiency through the use of material flows of individual links and reduces the anthropogenic load on the environment.

Claims (64)

1. Complex for the processing of main natural gas into marketable products, including: - pipeline branch of the main natural gas supply for processing 100; - gas processing unit 200, which produces commercial natural gas fully prepared for liquefaction, ethane fraction, separation products of a wide fraction of light hydrocarbons (hereinafter NGL) in the form of propane fraction, butane fraction, pentane-hexane fraction (hereinafter PGF); - pipeline for supplying commercial natural gas to the main gas pipeline 300; - block of production of liquefied natural gas (hereinafter LNG) 400; - storage unit for commercial products 500; - block for shipment of commercial products 600; combined by direct and feedback in the form of pipelines, while the composition of the specified gas processing unit 200 includes the following links: - link for measuring and accounting of raw natural gas 201; - link of absorption cleaning from acidic components and methanol 202; - link of deep adsorption drying and mercury removal 203; - link for rectification extraction of ethane fraction and NGL 204; - Compression link 205; - chill-down link 206; - link for metering and accounting of commercial natural gas 207; - link for cleaning and fractionation of NGL 208; - link for metering and accounting of dry natural gas, ethane and propane fractions supplied to the gas chemical production facility 209; - link for preparation of low pressure fuel gas 210; - a link for processing recoverable impurities 211; - a link for preparing a solution of absorbent 212; - link for preparation of demineralized water 213; - nitrogen production link 214; - high pressure fuel gas preparation link 215; This LNG 400 production unit includes the following links: - liquefaction link 401; - link for preparation and compression of refrigerant 402; the structure of the specified storage unit for commercial products 500 includes the following links: - LNG storage link 501; - link for compression of boil-off gas 502; - a link for the storage of liquefied petroleum gas (hereinafter referred to as LPG) and PGF under pressure of 503; - link for chilling and thermostating SUG 504; - link of isothermal storage of LPG 505; - link for preparation of low pressure fuel gas 506; the structure of the specified block for the shipment of commercial products 600 includes the following links: - LNG shipping link 601; - link of shipment of LPG 602; - shipping link PGF 603; in this case, one or more of the following additional connections are provided between the links of the blocks of the complex: a) feeding the regeneration waste gas from the link 203 to the link 202 using a compressor for mixing with the raw natural gas before the absorber of the link 202 with incomplete extraction of methanol from the raw natural gas in the link 202 with additional purification of purified natural gas in the link 203 or with purified natural gas after the absorber of the link 202 during deep purification of raw natural gas from methanol in the link 202 without additional treatment in the link 203; b) supplying the expanser gas from the link 202 to the link 210 for use as a fuel gas or to the link 211 for thermal and / or catalytic oxidation with the subsequent disposal of the resulting products; c) the supply of water extracted from the regeneration waste gas when it is cooled and / or extracted on coalescer filters from the purified natural gas in front of the adsorbers, from the link 203 to the link 202 to the loop of the aqueous absorbent solution or to the acidic water loop or to the link 211 for thermal oxidation at high methanol content; d) supplying acid gases from the reflux vessel of the stripper of unit 202 to unit 211 for thermal and / or catalytic oxidation or to unit 205 or 402 for mixing with turbine flue gases; e) partial or complete supply of acidic water from the reflux vessel of the stripper of unit 202 to unit 211 for thermal and / or catalytic oxidation; f) supplying water after it has been stripped from methanol from link 211 to link 202 into the loop of the aqueous absorbent solution; g) supply of dry natural gas from link 204 to link 209 for subsequent use as raw material and / or fuel gas for gas chemical production; h) supplying the ethane fraction from unit 204 to unit 402 to feed the ethane refrigerant circuit and / or the mixed refrigerant circuit or circuits and / or to the unit 401 to control the calorific value of the LNG; i) partial or complete supply of the ethane fraction from unit 204 to unit 504 with an excess of ethane fraction produced at the gas processing unit 200; j) supply of ethane fraction from unit 204 to unit 205 for mixing with dry natural gas with a decrease or absence of ethane fraction consumption in gas chemical production; k) supplying propane refrigerant from unit 206 to unit 204 for condensing vapors from the deethanizer column and / or cooling the dried natural gas and / or cooling the dry natural gas recycle; l) supply of propane refrigerant from link 206 to link 205 for cooling compressed natural gas from the discharge of the compressors after air coolers (hereinafter AVO); m) supplying compressed natural gas from link 205 after the first compression stage before or after AVO to link 208 for use as regeneration gas and / or refrigeration gas; o) supplying dry natural gas from link 204 or compressed natural gas from the compressor discharge of link 205 to link 402 to feed the mixed refrigerant circuit or circuits; o) supplying the regeneration waste gas and / or cooling gas from the link 208 to the link 210 for use as a fuel gas, and / or to the link 211 for thermal and / or catalytic oxidation, and / or to the link 207 for mixing with commercial natural gas , and / or link 205 or 402 for mixing with turbine flue gases; p) supplying stripping gas from unit 502 to unit 402 for use as a gas turbine fuel and / or to unit 215 for use as a primary source of high pressure fuel gas; c) supplying raw natural gas from link 201 and / or compressed natural gas from the first compressor stage of link 205 to link 215 for use as a high pressure fuel gas make-up when the amount of stripping gas from link 502 is insufficient; r) supplying dry natural gas from link 204 to link 210 for use as the primary source of low pressure fuel gas; s) supplying raw natural gas from link 201 and / or compressed natural gas from the discharge of the compressors of link 205 to link 210 for use as a low pressure fuel gas make-up when the amount of dry natural gas from link 204 is insufficient; t) feeding the propane fraction from the link 208 and / or from the link 503 to the link 401 to regulate the calorific value of LNG, and / or to the link 402 to feed the mixed refrigerant circuit or circuits, and / or to the link 206 to fill and feed the propane refrigerant circuit ; x) feeding the butane cut from unit 208 to unit 402 to feed the mixed refrigerant circuit or circuits; v) supply of propane, and / or butane, and / or pentane-hexane fractions from unit 503 to unit 207 for mixing with commercial natural gas with a periodic decrease or absence of their consumption or during the production of substandard LPG and / or PGF; h) feeding hydrocarbon condensate from link 202 to link 503 for mixing with PGF. 2. The complex according to claim 1, characterized in that the block 200 is supplemented with a unit for producing elemental sulfur 216 using the Claus method and supplying acid gases from the reflux tank of the desorber unit 202. 3. The complex according to claim 1, characterized in that the unit 200 is supplemented with an acid gas compression unit 217 for supplying acid gases from the reflux tank of the desorber unit 202 for mixing with commercial natural gas before unit 207 after removing a part of the commercial natural gas, completely prepared for liquefaction , link 401 and / or for the production of methanol and / or urea, and / or other products. 4. The complex according to claim 1, characterized in that the unit 200 is supplemented with a regeneration gas purification unit 218 for extracting mercaptans and / or methanol from the regeneration waste gas of unit 208 with the supply of purified regeneration gas from unit 218 to unit 210 as fuel gas and / or link 205 for mixing with dry natural gas or link 207 for mixing with commercial natural gas.

Images