Device for preparing LNG (Liquefied Natural Gas) and co-producing LC2H6, LPG (Liquefied Petroleum Gas) and condensate oil from high calorific value coal gas

Abstract

The utility model relates to a device for preparing LNG (Liquefied Natural Gas) and co-producing LC2H6, LPG (Liquefied Petroleum Gas) and condensate oil by using high calorific value coal gas, which comprises a mixed refrigerant refrigeration cycle, a nitrogen refrigeration cycle and a propane refrigeration cycle, the mixed refrigerant refrigeration cycle provides cold energy for condensation and liquefaction of raw material gas and nitrogen, liquefaction and supercooling of LNG and liquefaction and supercooling of ethane, and the propane refrigeration cycle provides cold energy for condensation and liquefaction of liquefied natural gas and nitrogen. The nitrogen cycle provides cooling capacity for cryogenic separation of raw material gas, the propane refrigeration cycle provides cooling capacity for separation of ethane, meanwhile, a demethanizing tower, a dehydrogenation tower, an LNG rectifying tower, a deethanizing tower and a liquefied petroleum gas tower are arranged, liquid ethane, LPG and condensate oil are co-produced while high-calorific-value coal gas is separated through rectification and LNG is produced, the factory energy consumption is reduced, the benefits are increased, and meanwhile, the production cost is reduced. And the method has the advantages of high adaptability, safety, reliability, wide practicability and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of low-temperature deep-cold liquefaction separation, in particular to a device for producing LNG from high calorific value coal gas and co-producing LC2H6, LPG and condensate oil. Background Art

[0002] The coal gas produced by the low-temperature pyrolysis of low-rank coal, coal, oil, gas and electricity integrated multi-generation technology has high methane content, low inert components and high calorific value. Its main components are hydrogen, carbon monoxide, methane, ethane, propane, butane, pentane, nitrogen, etc. The high calorific value coal gas produced is used to produce LNG, and liquid ethane, LPG, condensate oil and hydrogen-rich gas are co-produced, which not only reduces the waste of resources and environmental pollution, but also maximizes the added value of products.

[0003] In conventional methane cryogenic separation devices, the purified gas first enters the cold box, where it undergoes cryogenic liquefaction separation to produce LNG and hydrogen-rich tail gas. The hydrogen-rich tail gas separated by the cold box then enters the PSA process to extract hydrogen, make up nitrogen, and finally enter the synthetic ammonia synthesis process. + The high hydrocarbon content will result in the calorific value of LNG being too high if the conventional process mentioned above is adopted, which will affect the sales of products, such as C5 + When the content increases, the low-temperature section of the cold box will freeze and become blocked, which will greatly affect the stability of the device. Utility Model Content

[0004] The purpose of the utility model is to overcome the shortcomings and deficiencies of the above-mentioned prior art and to provide a device for producing LNG from high calorific value coal gas and co-producing LC2H6, LPG and condensate oil with simple process, flexible adjustment, reliable operation, easy operation and low energy consumption.

[0005] In order to solve the above problems, the technical solution adopted by the utility model is:

[0006] A device for preparing LNG and co-producing LC2H6, LPG and condensate from high calorific value coal gas, the device comprises a demethanizer, a main heat exchanger, a heavy hydrocarbon separator, a raw gas low-temperature separator, a supercooler, a dehydrogenation tower, a dehydrogenation tower condenser, a dehydrogenation tower reflux tank, an LNG distillation tower, an LNG distillation tower condenser, an LNG distillation tower reflux tank, an LNG distillation tower reboiler, a deethanizer, a deethanizer, a deethanizer condenser, a deethanizer reflux tank, a deethanizer liquid reflux pump, a deethanizer reboiler, a condensate heat exchanger, a liquefied petroleum gas tower, a liquefied petroleum gas tower condenser, a liquefied petroleum gas tower reflux tank, a liquefied petroleum gas tower liquid reflux pump, an LPG cooler, a liquefied petroleum gas tower reboiler, a condensate cooler, a nitrogen compression system, a mixed refrigerant compressor system, a cold The main heat exchanger is provided with a raw gas I channel, a raw gas II channel, a hydrocarbon liquid channel, an LNG channel, a raw gas III channel, a raw gas IV channel, an ethane channel, a hydrogen-rich gas I channel, a nitrogen-rich gas I channel, a medium-pressure nitrogen gas I channel, a reflux nitrogen gas I channel, a reflux refrigerant channel, a high-pressure gas-phase refrigerant channel I, a high-pressure liquid-phase refrigerant channel II, and a high-pressure liquid-phase refrigerant channel II. The subcooler is provided with a hydrogen-rich gas II channel, a nitrogen-rich gas II channel, a medium-pressure liquid nitrogen I channel, and a reflux liquid nitrogen I channel. The dehydrogenation tower condenser is provided with hydrogen-rich gas III and reflux liquid nitrogen II channels. The LNG distillation tower condenser is provided with a rich gas III channel and a reflux liquid nitrogen II channel. Nitrogen III channel and reflux liquid nitrogen III channel, the raw gas after external purification is divided into two paths, one path of raw gas is connected to the demethanizer feed port, the other path of raw gas pipeline is connected to the raw gas pipeline, the demethanizer outlet is connected to the raw gas I channel inlet, the raw gas I channel outlet is connected to the heavy hydrocarbon separator feed port, the heavy hydrocarbon separator bottom liquid phase outlet is connected to the demethanizer inlet, the heavy hydrocarbon separator top gas phase outlet is connected to the raw gas II channel inlet, the raw gas II channel outlet is connected to the raw gas low temperature separator feed port, the raw gas low temperature separator bottom liquid phase outlet is connected to the demethanizer inlet, the raw gas low temperature separator top gas phase outlet is connected to the raw gas IV channel inlet The outlet of the raw gas IV channel is connected to the feed port of the dehydrogenation tower, the middle outlet of the demethanizer is connected to the inlet of the hydrocarbon liquid channel, the outlet of the hydrocarbon liquid channel is connected to the middle inlet of the demethanizer, the liquid phase outlet at the bottom of the demethanizer is connected to the condensate inlet of the condensate heat exchanger, the condensate outlet of the condensate heat exchanger is connected to the feed port of the deethanizer, the gas phase outlet at the top of the demethanizer is connected to the inlet of the raw gas III channel, the outlet of the raw gas III channel is connected to the feed port of the LNG distillation tower, the liquid phase outlet at the bottom of the dehydrogenator is connected to the feed port of the LNG distillation tower, the gas phase outlet at the top of the dehydrogenator is connected to the inlet of the hydrogen-rich gas III, and the hydrogen-rich gas III outlet is connected to the feed port of the dehydrogenation tower reflux tank,The liquid phase outlet at the bottom of the dehydrogenation tower reflux tank is connected to the feed port of the dehydrogenation tower, the gas phase outlet at the top of the dehydrogenation tower reflux tank is connected to the inlet of the hydrogen-rich gas II channel, the outlet of the hydrogen-rich gas II channel is connected to the inlet of the hydrogen-rich gas I channel, the outlet of the hydrogen-rich gas I channel is connected to the external hydrogen-rich gas pipeline, the liquid phase outlet at the bottom of the LNG distillation tower is connected to the inlet of the LNG channel, the outlet of the LNG channel is connected to the LNG pipeline outside the boundary to the LNG storage tank, the gas phase outlet at the top of the LNG distillation tower is connected to the inlet of the nitrogen-rich gas III channel, the outlet of the nitrogen-rich gas III channel is connected to the feed port of the LNG distillation tower reflux tank, the liquid phase outlet at the bottom of the LNG distillation tower reflux tank is connected to the feed port of the LNG distillation tower, the The gas phase outlet at the top of the reflux tank of the LNG distillation tower is connected to the inlet of the nitrogen-rich gas II channel, the outlet of the nitrogen-rich gas II channel is connected to the inlet of the nitrogen-rich gas I channel, the outlet of the nitrogen-rich gas I channel is connected to the external nitrogen-rich tail gas pipeline, the liquid phase outlet at the bottom of the deethanizer is connected to the mixed hydrocarbon inlet of the condensate heat exchanger, the mixed hydrocarbon outlet of the condensate heat exchanger is connected to the inlet of the mixed hydrocarbon booster pump, the outlet of the mixed hydrocarbon booster pump is connected to the feed port of the liquefied petroleum gas tower, the gas phase outlet at the top of the deethanizer is connected to the ethane inlet of the deethanizer condenser, the ethane outlet of the deethanizer condenser is connected to the feed port of the deethanizer reflux tank, the gas phase outlet at the top of the deethanizer reflux tank is connected to the outside fuel gas pipeline, the bottom of the deethanizer reflux tank is connected to the ethane inlet of the deethanizer condenser, the ethane outlet of the deethanizer condenser is connected to the feed port of the deethanizer reflux tank, the gas phase outlet at the top of the deethanizer reflux tank is connected to the outside fuel gas pipeline, The liquid phase outlet of the deethanizer is connected to the inlet of the liquid reflux pump of the deethanizer. The outlet of the deethanizer liquid reflux pump is divided into two parts, one part is connected to the inlet of the deethanizer, and the other part is connected to the inlet of the ethane channel. The outlet of the ethane channel is connected to the pipeline of liquid ethane to LC2H6 storage tank outside the boundary. The outlet of the deethanizer is connected to the mixed hydrocarbon inlet of the deethanizer reboiler. The mixed hydrocarbon outlet of the deethanizer reboiler is connected to the inlet of the deethanizer. The liquid phase outlet at the bottom of the liquefied petroleum gas tower is connected to the condensate inlet of the condensate cooler. The condensate outlet of the condensate cooler is connected to the pipeline of condensate to condensate storage tank outside the boundary. The gas phase outlet at the top of the liquefied petroleum gas tower is connected to the LPG inlet of the condenser of the liquefied petroleum gas tower. The LPG outlet of the liquefied petroleum gas tower condenser is connected to the feed port of the liquefied petroleum gas tower reflux tank, the gas phase outlet at the top of the liquefied petroleum gas tower reflux tank is connected to the fuel gas pipeline outside the boundary, the liquid phase outlet at the bottom of the liquefied petroleum gas tower reflux tank is connected to the inlet of the liquefied petroleum gas tower liquid reflux pump, the outlet of the liquefied petroleum gas tower liquid reflux pump is divided into two parts, one part is connected to the inlet of the liquefied petroleum gas tower, and the other part is connected to the LPG inlet of the LPG cooler, the LPG outlet of the LPG cooler is connected to the LPG to LPG storage tank pipeline outside the boundary, the liquefied petroleum gas tower outlet is connected to the condensate oil inlet of the liquefied petroleum gas tower reboiler, and the condensate oil outlet of the liquefied petroleum gas tower reboiler is connected to the inlet of the liquefied petroleum gas tower,The medium-pressure nitrogen channel I inlet is connected to the outlet of the nitrogen compression system, the medium-pressure nitrogen channel I outlet is connected to the medium-pressure liquid nitrogen channel I inlet, the medium-pressure liquid nitrogen channel I outlets are connected to the reflux liquid nitrogen II channel inlet and the reflux liquid nitrogen III channel inlet, the reflux liquid nitrogen I channel inlet is connected to the reflux liquid nitrogen II channel outlet and the reflux liquid nitrogen III channel outlet, the reflux liquid nitrogen I channel outlet is connected to the reflux nitrogen channel I inlet, the reflux nitrogen channel I outlet is connected to the nitrogen compression system inlet, the high-pressure liquid phase refrigerant channel I inlet is connected to the liquid phase outlet of the mixed refrigerant compressor system, the high-pressure liquid phase refrigerant channel I outlet is connected to the reflux refrigerant channel inlet, the high-pressure gas phase refrigerant channel I inlet is connected to the mixed refrigerant compressor system The gas phase outlet is connected, the high-pressure gas phase refrigerant channel I outlet is connected to the refrigerant separator feed port, the refrigerant separator gas phase outlet is connected to the high-pressure gas phase refrigerant channel II inlet, the high-pressure gas phase refrigerant channel II outlet is connected to the reflux refrigerant channel inlet, the refrigerant separator liquid phase outlet is connected to the high-pressure liquid phase refrigerant channel II inlet, the high-pressure liquid phase refrigerant channel II outlet is connected to the refrigerant inlet of the LNG distillation tower reboiler, the refrigerant outlet of the LNG distillation tower reboiler is connected to the reflux refrigerant channel inlet, the reflux refrigerant channel outlet is connected to the mixed refrigerant compressor system inlet, the propane inlet of the deethanizer condenser is connected to the propane compressor system outlet, and the propane outlet of the deethanizer condenser is connected to the propane compressor system inlet.

[0007] Preferably, the raw gas pipeline is provided with a regulating valve a for adjusting the temperature at the bottom of the demethanizer.

[0008] Preferably, a regulating valve b is provided on the liquid phase outlet pipeline at the bottom of the heavy hydrocarbon separator to adjust the liquid level at the bottom of the heavy hydrocarbon separator.

[0009] Preferably, a regulating valve c is provided on the liquid phase outlet pipeline at the bottom of the raw gas low-temperature separator for adjusting the liquid level at the bottom of the raw gas low-temperature separator.

[0010] Preferably, the liquid phase outlet pipeline at the bottom of the demethanizer is provided with a regulating valve d for adjusting the liquid level at the bottom of the demethanizer.

[0011] Preferably, a regulating valve e is provided on the pipeline at the outlet of the LNG channel for adjusting the liquid level at the bottom of the LNG distillation tower.

[0012] Preferably, the outlet pipeline of the ethane channel is provided with a regulating valve f for adjusting the liquid level at the bottom of the deethanizer reflux tank.

[0013] Preferably, a regulating valve g is provided on the pipeline at the outlet of the high-pressure liquid-phase refrigerant channel I.

[0014] Preferably, a regulating valve h is provided on the pipeline at the outlet of the high-pressure liquid-phase refrigerant channel II.

[0015] Preferably, a regulating valve i is provided on the pipeline at the outlet of the high-pressure gas-phase refrigerant channel II.

[0016] Preferably, a regulating valve j is provided at the inlet pipeline of the reflux liquid nitrogen II channel for adjusting the temperature of the outlet of the hydrogen-rich gas III.

[0017] Preferably, the liquid phase outlet pipeline at the bottom of the dehydrogenation tower is provided with a regulating valve k for adjusting the liquid level at the bottom of the dehydrogenation tower.

[0018] Preferably, a regulating valve 1 is provided at the inlet pipeline of the reflux liquid nitrogen III channel for adjusting the temperature of the outlet of the nitrogen-rich gas III channel.

[0019] Preferably, a regulating valve m is provided on the bypass line of the reboiler of the LNG distillation tower to adjust the temperature at the bottom of the LNG distillation tower.

[0020] Preferably, a regulating valve n is provided on the bypass line of the medium-pressure liquid nitrogen and the reflux liquid nitrogen.

[0021] Preferably, the propane inlet pipeline of the deethanizer condenser is provided with a regulating valve o for adjusting the temperature at the top of the deethanizer.

[0022] Preferably, a regulating valve p is provided on the gas phase outlet pipeline at the top of the deethanizer reflux tank to adjust the pressure at the top of the deethanizer.

[0023] Preferably, a regulating valve r is provided on the steam line of the deethanizer reboiler to adjust the temperature at the bottom of the deethanizer.

[0024] Preferably, a regulating valve s is provided on the liquid phase outlet pipeline at the bottom of the deethanizer to adjust the liquid level at the bottom of the deethanizer.

[0025] Preferably, a regulating valve t is provided on the gas phase outlet pipeline at the top of the reflux tank of the liquefied petroleum gas tower to adjust the pressure at the top of the liquefied petroleum gas tower.

[0026] Preferably, the LPG cooler outlet pipeline is provided with a regulating valve u for adjusting the liquid level at the bottom of the liquefied petroleum gas tower reflux tank.

[0027] Preferably, a regulating valve v is provided on the steam pipeline of the liquefied petroleum gas tower reboiler to adjust the temperature at the bottom of the liquefied petroleum gas tower.

[0028] Preferably, the liquid phase outlet pipeline at the bottom of the liquefied petroleum gas tower is provided with a regulating valve w for adjusting the liquid level at the bottom of the liquefied petroleum gas tower.

[0029] Preferably, the outlet pipeline of the hydrogen-rich gas channel I is provided with a regulating valve x for adjusting the pressure at the top of the dehydrogenation tower.

[0030] Preferably, the outlet pipeline of the nitrogen-rich gas channel I is provided with a regulating valve y for adjusting the pressure at the top of the LNG distillation tower.

[0031] Preferably, the outlet pipeline of the raw gas III channel is provided with a regulating valve z.

[0032] Preferably, the LNG distillation tower reboiler can be internal or external.

[0033] Preferably, the demethanizer, dehydrogenator, LNG distillation tower, deethanizer and liquefied petroleum gas tower are packed towers or plate towers.

[0034] Based on the above technical solution, the following technical effects can be produced:

[0035] 1. Low energy consumption: The condensation and liquefaction of raw gas and nitrogen, the liquefaction and supercooling of LNG, and the liquefaction and supercooling of ethane are provided by the mixed refrigerant refrigeration cycle, that is, providing a cold source in the temperature range of -162 to 40°C. The cryogenic separation of raw gas is provided by the nitrogen cycle, that is, providing a cold source in the temperature range of -185 to -162°C. The separation of ethane is provided by the propane cycle, that is, providing a cold source in the temperature range of -30 to -10°C. This process realizes different temperature ranges and different cold capacity distribution, reducing the energy consumption of the entire device.

[0036] 2. The raw gas utilization rate is high, which can adapt to different load conditions and has low equipment investment. It can produce liquid ethane, LPG and condensate oil while producing LNG. Compared with the conventional coke oven gas to LNG, it has added a light hydrocarbon recovery device.

[0037] 3. Higher methane and hydrogen yields: Since the gas phase at the top of the demethanizer is cooled and the supercooled liquid and the liquid from the dehydrogenation tower are both fed into the LNG distillation tower for distillation, the methane recovery rate is increased and the hydrogen recovery rate is increased.

[0038] 4. High purity of LNG products: Due to the installation of LNG distillation tower, LNG distillation tower condenser and LNG distillation tower reboiler in the process, the cooling capacity of liquid nitrogen after throttling is used as the cold source of the LNG distillation tower condenser, and the mixed refrigerant is used as the heat source of the LNG distillation tower reboiler, so that the LNG product has high purity.

[0039] 5. High purity of LC2H6 product: Due to the deethanizer, deethanizer condenser and deethanizer reboiler set up in the process, the cooling capacity after propane throttling is used as the cold source of the deethanizer condenser, and saturated steam is used as the heat source of the deethanizer reboiler, so that the C2H6 content in the product liquid ethane is higher than 90%, and C3 +The hydrocarbon content is less than 10%.

[0040] 6. LPG products must meet the quality requirements of "Liquefied Petroleum Gas" (GB11174-2011): the (C3+C4) hydrocarbon content in the LPG product is higher than 95%, C5 and C5 + The hydrocarbon content is less than 3%.

[0041] 7. Condensate oil products meet the requirements: C4H 10 Hydrocarbon content less than 10%, C5 and C5 + The hydrocarbon content is higher than 90%.

[0042] 8. In addition, it has the advantages of easy maintenance, reliable operation, safety and reliability, and wide practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a structural schematic diagram of the utility model.

[0044] In the figure: 1-demethanizer, 2-main heat exchanger, 3-heavy hydrocarbon separator, 4-raw gas low-temperature separator, 5-subcooler, 6-dehydrogenation tower, 7-dehydrogenation tower condenser, 8-dehydrogenation tower reflux tank, 9-LNG distillation tower, 10-LNG distillation tower condenser, 11-LNG distillation tower reflux tank, 12-LNG distillation tower reboiler, 13-deethanizer, 14-deethanizer condenser, 15-deethanizer reflux tank, 16-deethanizer liquid reflux pump, 17-deethanizer reboiler, 18-condensate heat exchanger, 19-liquefied petroleum gas tower, 20-liquefied petroleum gas tower condenser, 21- LPG tower reflux tank, 22- LPG tower liquid reflux pump, 23-LPG cooler, 24- LPG tower reboiler, 25- condensate cooler, 26- nitrogen compression system, 27- mixed refrigerant compressor system, 28- refrigerant separator, 29- propane compressor system, 30- mixed hydrocarbon booster pump; 101- regulating valve a, 102- regulating valve b, 103- regulating valve c, 104- regulating valve d, 105- regulating valve e, 106- regulating valve f, 107- regulating valve g, 108- regulating valve h, 109- regulating valve i, 110- regulating valve j, 111 - regulating valve k, 112- regulating valve l, 113- regulating valve m, 114- regulating valve n, 115- regulating valve o, 116- regulating valve p, 118- regulating valve r, 119- regulating valve s, 120- regulating valve t, 121- regulating valve u, 122- regulating valve v, 123- regulating valve w, 124- regulating valve x, 125- regulating valve y, 126- regulating valve z; A1- raw gas I channel, A2- raw gas II channel, A3- hydrocarbon liquid channel, A4- LNG channel, A5- raw gas III channel, A6- raw gas IV channel, A7- ethane channel, A8- raw gas III channel, A9- raw gas IV channel, A10- raw gas III channel, A111- raw gas IV channel, A122- raw gas IV channel, A13- ethane channel, A14- raw gas III channel, A15- raw gas IV channel, A16- raw gas IV channel, A17- ethane channel, A18- raw gas III channel, A19- raw gas IV channel, A20- raw gas IV channel, A211- ethane channel, A222- raw gas IV channel, A23- ethane channel, A242- 8-hydrogen-rich gas I channel, A9-nitrogen-rich gas I channel, A10-medium-pressure nitrogen gas I channel, A11-reflux nitrogen gas I channel, A12-reflux refrigerant channel, A13-high-pressure gas-phase refrigerant channel I, A14-high-pressure liquid-phase refrigerant channel I, A15-high-pressure gas-phase refrigerant channel II, A16-high-pressure liquid-phase refrigerant channel II, B1-hydrogen-rich gas II channel, B2-nitrogen-rich gas II channel, B3-medium-pressure liquid nitrogen I channel, B4-reflux liquid nitrogen I channel, C1-hydrogen-rich gas III, C2-reflux liquid nitrogen II channel, D1-nitrogen-rich gas III channel, D2-reflux liquid nitrogen III channel. DETAILED DESCRIPTION

[0045] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0046] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0047] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0048] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0049] like Figure 1 As shown, embodiment 1: a device for producing LNG from high calorific value coal gas and co-producing LC2H6, LPG and condensate, which includes a demethanizer 1, a main heat exchanger 2, a heavy hydrocarbon separator 3, a raw gas low-temperature separator 4, a subcooler 5, a dehydrogenation tower 6, a dehydrogenation tower condenser 7, a dehydrogenation tower reflux tank 8, an LNG distillation tower 9, an LNG distillation tower condenser 10, an LNG distillation tower reflux tank 11, an LNG distillation tower reboiler 12, a deethanizer 13, a deethanizer condenser 14, a deethanizer Tower reflux tank 15, deethanizer liquid reflux pump 16, deethanizer reboiler 17, condensate heat exchanger 18, liquefied petroleum gas tower 19, liquefied petroleum gas tower condenser 20, liquefied petroleum gas tower reflux tank 21, liquefied petroleum gas tower liquid reflux pump 22, LPG cooler 23, liquefied petroleum gas tower reboiler 24, condensate oil cooler 25, nitrogen compression system 26, mixed refrigerant compressor system 27, refrigerant separator 28, propane compressor system 29, mixed hydrocarbon booster pump 30.

[0050] The main heat exchanger 2 is provided with a raw gas I channel A1, a raw gas II channel A2, a hydrocarbon liquid channel A3, an LNG channel A4, a raw gas III channel A5, a raw gas IV channel A6, an ethane channel A7, a hydrogen-rich gas I channel A8, a nitrogen-rich gas I channel A9, a medium-pressure nitrogen gas I channel A10, a reflux nitrogen gas I channel A11, a reflux refrigerant channel A12, a high-pressure gas phase refrigerant channel IA13, a high-pressure liquid phase refrigerant channel IA14, a high-pressure gas phase refrigerant channel IIA15, and a high-pressure liquid phase refrigerant channel IIA16.

[0051] The subcooler 5 is provided with a hydrogen-rich gas II channel B1, a nitrogen-rich gas II channel B2, a medium-pressure liquid nitrogen I channel B3, and a reflux liquid nitrogen I channel B4.

[0052] The LNG distillation tower condenser 10 is provided with a nitrogen-rich gas III channel D1 and a reflux liquid nitrogen III channel D2.

[0053] The raw gas after external purification is divided into two paths, one path of raw gas is connected to the feed port of the demethanizer 1, and the other path of raw gas pipeline is connected to the raw gas pipeline, the outlet of the demethanizer 1 is connected to the inlet of the raw gas I channel A1, the outlet of the raw gas I channel A1 is connected to the feed port of the heavy hydrocarbon separator 3, the bottom liquid phase outlet of the heavy hydrocarbon separator 3 is connected to the inlet of the demethanizer 1, the top gas phase outlet of the heavy hydrocarbon separator 3 is connected to the inlet of the raw gas II channel A2, the outlet of the raw gas II channel A2 is connected to the feed port of the raw gas low-temperature separator 4, the bottom liquid phase outlet of the raw gas low-temperature separator 4 is connected to the inlet of the demethanizer 1, and the top gas phase outlet of the raw gas low-temperature separator 4 is connected to the raw gas IV The inlet of channel A6 is connected, the outlet of raw gas IV channel A6 is connected to the feed port of dehydrogenation tower 6, the middle outlet of demethanizer 1 is connected to the inlet of hydrocarbon liquid channel A3, the outlet of hydrocarbon liquid channel A3 is connected to the middle inlet of demethanizer 1, the bottom liquid phase outlet of demethanizer 1 is connected to the condensate inlet of condensate heat exchanger 18, the condensate outlet of condensate heat exchanger 18 is connected to the feed port of deethanizer 13, the top gas phase outlet of demethanizer 1 is connected to the inlet of raw gas III channel A5, the outlet of raw gas III channel A5 is connected to the feed port of LNG distillation tower 9, the bottom liquid phase outlet of dehydrogenation tower 6 is connected to the feed port of LNG distillation tower 9, the top gas phase outlet of dehydrogenation tower 6 is connected to The hydrogen-rich IIIC1 inlet is connected, the hydrogen-rich IIIC1 outlet is connected to the feed port of the dehydrogenation tower reflux tank 8, the liquid phase outlet at the bottom of the dehydrogenation tower reflux tank 8 is connected to the feed port of the dehydrogenation tower 6, the gas phase outlet at the top of the dehydrogenation tower reflux tank 8 is connected to the inlet of the hydrogen-rich II channel B1, the outlet of the hydrogen-rich II channel B1 is connected to the inlet of the hydrogen-rich I channel A8, the outlet of the hydrogen-rich I channel A8 is connected to the external hydrogen-rich pipeline, the liquid phase outlet at the bottom of the LNG distillation tower 9 is connected to the inlet of the LNG channel A4, the outlet of the LNG channel A4 is connected to the LNG to LNG storage tank pipeline outside the boundary, and the gas phase outlet at the top of the LNG distillation tower 9 is connected to the inlet of the nitrogen-rich III channel D1 The outlet of nitrogen-rich gas III channel D1 is connected to the feed port of LNG distillation tower reflux tank 11, the bottom liquid phase outlet of LNG distillation tower reflux tank 11 is connected to the feed port of LNG distillation tower 9, the top gas phase outlet of LNG distillation tower reflux tank 11 is connected to the inlet of nitrogen-rich gas II channel B2, the outlet of nitrogen-rich gas II channel B2 is connected to the inlet of nitrogen-rich gas I channel A9, the outlet of nitrogen-rich gas I channel A9 is connected to the external nitrogen-rich tail gas pipeline, the bottom liquid phase outlet of deethanizer 13 is connected to the mixed hydrocarbon inlet of condensate heat exchanger 18, the mixed hydrocarbon outlet of condensate heat exchanger 18 is connected to the inlet of mixed hydrocarbon booster pump 30, and the outlet of mixed hydrocarbon booster pump 30 is connected to the feed port of liquefied petroleum gas tower 19,The gas phase outlet at the top of the deethanizer 13 is connected to the ethane inlet of the deethanizer condenser 14, the ethane outlet of the deethanizer condenser 14 is connected to the feed port of the deethanizer reflux tank 15, the gas phase outlet at the top of the deethanizer reflux tank 15 is connected to the fuel gas pipeline outside the boundary, the liquid phase outlet at the bottom of the deethanizer reflux tank 15 is connected to the inlet of the deethanizer liquid reflux pump 16, the outlet of the deethanizer liquid reflux pump 16 is divided into two parts, one part is connected to the inlet of the deethanizer 13, and the other part is connected to the inlet of the ethane channel A7, the outlet of the ethane channel A7 is connected to the liquid ethane out of the boundary LC2H6 storage tank pipeline, the outlet of the deethanizer 13 is connected to the mixed hydrocarbon inlet of the deethanizer reboiler 17 The mixed hydrocarbon outlet of the deethanizer reboiler 17 is connected to the inlet of the deethanizer 13, the liquid phase outlet at the bottom of the liquefied petroleum gas tower 19 is connected to the condensate inlet of the condensate cooler 25, the condensate outlet of the condensate cooler 25 is connected to the condensate to condensate storage tank pipeline outside the boundary, the gas phase outlet at the top of the liquefied petroleum gas tower 19 is connected to the LPG inlet of the liquefied petroleum gas tower condenser 20, the LPG outlet of the liquefied petroleum gas tower condenser 20 is connected to the feed port of the liquefied petroleum gas tower reflux tank 21, the gas phase outlet at the top of the liquefied petroleum gas tower reflux tank 21 is connected to the fuel gas pipeline outside the boundary, and the liquid phase outlet at the bottom of the liquefied petroleum gas tower reflux tank 21 is connected to the liquefied petroleum gas tower liquid reflux pump 2 2 inlet, the outlet of the liquefied petroleum gas tower liquid reflux pump 22 is divided into two parts, one part is connected to the inlet of the liquefied petroleum gas tower 19, and the other part is connected to the LPG inlet of the LPG cooler 23. The LPG outlet of the LPG cooler 23 is connected to the LPG to LPG storage tank pipeline outside the boundary. The outlet of the liquefied petroleum gas tower 19 is connected to the condensate inlet of the liquefied petroleum gas tower reboiler 24. The condensate outlet of the liquefied petroleum gas tower reboiler 24 is connected to the inlet of the liquefied petroleum gas tower 19. The inlet of the medium-pressure nitrogen I channel A10 is connected to the outlet of the nitrogen compression system 26. The outlet of the medium-pressure nitrogen I channel A10 is connected to the inlet of the medium-pressure liquid nitrogen I channel B3. 3 outlets are connected to the inlet of the reflux liquid nitrogen II channel C2 and the inlet of the reflux liquid nitrogen III channel D2, the inlet of the reflux liquid nitrogen I channel B4 is connected to the outlet of the reflux liquid nitrogen II channel C2 and the outlet of the reflux liquid nitrogen III channel D2, the outlet of the reflux liquid nitrogen I channel B4 is connected to the inlet of the reflux nitrogen gas I channel A11, the outlet of the reflux nitrogen gas I channel A11 is connected to the inlet of the nitrogen compression system 26, the inlet of the high-pressure liquid phase refrigerant channel IA14 is connected to the liquid phase outlet of the mixed refrigerant compressor system 27, the outlet of the high-pressure liquid phase refrigerant channel IA14 is connected to the inlet of the reflux refrigerant channel A12, the inlet of the high-pressure gas phase refrigerant channel IA13 is connected to the gas phase outlet of the mixed refrigerant compressor system 27,The outlet of the high-pressure gas phase refrigerant channel IA13 is connected to the feed port of the refrigerant separator 28, the gas phase outlet of the refrigerant separator 28 is connected to the inlet of the high-pressure gas phase refrigerant channel IIA15, the outlet of the high-pressure gas phase refrigerant channel IIA15 is connected to the inlet of the reflux refrigerant channel A12, the liquid phase outlet of the refrigerant separator 14 is connected to the inlet of the high-pressure liquid phase refrigerant channel IIA16, the outlet of the high-pressure liquid phase refrigerant channel IIA16 is connected to the refrigerant inlet of the LNG distillation tower reboiler 12, the refrigerant outlet of the LNG distillation tower reboiler 12 is connected to the inlet of the reflux refrigerant channel A12, the outlet of the reflux refrigerant channel A12 is connected to the inlet of the mixed refrigerant compressor system 27, the propane inlet of the deethanizer condenser 14 is connected to the outlet of the propane compressor system 29, and the propane outlet of the deethanizer condenser 14 is connected to the inlet of the propane compressor system 29.

[0054] The demethanizer 1, dehydrogenator 6, LNG distillation tower 9, deethanizer 13 and liquefied petroleum gas tower 19 are packed towers or plate towers.

[0055] The raw gas pipeline is provided with a regulating valve a101 for adjusting the temperature at the bottom of the demethanizer 1.

[0056] The liquid phase outlet pipeline at the bottom of the heavy hydrocarbon separator 3 is provided with a regulating valve b102 for adjusting the liquid level at the bottom of the heavy hydrocarbon separator 3 .

[0057] The liquid phase outlet pipeline at the bottom of the raw gas low-temperature separator 4 is provided with a regulating valve c103 for adjusting the liquid level at the bottom of the raw gas low-temperature separator 4 .

[0058] The liquid phase outlet pipeline at the bottom of the demethanizer 1 is provided with a regulating valve d104 for adjusting the liquid level at the bottom of the demethanizer 1 .

[0059] The pipeline at the outlet of the LNG channel A4 is provided with a regulating valve e105 for adjusting the liquid level at the bottom of the LNG distillation tower 9.

[0060] The outlet pipeline of the ethane channel A7 is provided with a regulating valve f106 for adjusting the liquid level at the bottom of the deethanizer reflux tank 15 .

[0061] A regulating valve g107 is provided on the pipeline at the outlet of the high-pressure liquid-phase refrigerant channel IA14.

[0062] A regulating valve h108 is provided on the pipeline at the outlet of the high-pressure liquid-phase refrigerant channel IIA16.

[0063] A regulating valve i109 is provided on the pipeline at the outlet of the high-pressure gas-phase refrigerant channel IIA15.

[0064] The inlet pipeline of the reflux liquid nitrogen II channel C2 is provided with a regulating valve j110 for adjusting the temperature of the outlet of the hydrogen-rich gas IIIC1.

[0065] The liquid phase outlet pipeline at the bottom of the dehydrogenation tower 6 is provided with a regulating valve k111 for adjusting the liquid level at the bottom of the dehydrogenation tower 6.

[0066] The inlet pipeline of the reflux liquid nitrogen III channel D2 is provided with a regulating valve 1112 for adjusting the temperature of the outlet of the nitrogen-rich gas III channel D1.

[0067] The bypass line of the LNG distillation tower reboiler 12 is provided with a regulating valve m113 for adjusting the temperature at the bottom of the LNG distillation tower 9.

[0068] The bypass pipeline of the medium-pressure liquid nitrogen and the reflux liquid nitrogen is provided with a regulating valve n114.

[0069] The propane inlet pipeline of the deethanizer condenser 14 is provided with a regulating valve o115 for adjusting the temperature at the top of the deethanizer 13.

[0070] The gas phase outlet pipeline at the top of the deethanizer reflux tank 15 is provided with a regulating valve p116 for adjusting the pressure at the top of the deethanizer 13 .

[0071] The steam pipeline of the deethanizer reboiler 17 is provided with a regulating valve r118 for adjusting the temperature at the bottom of the deethanizer 13 .

[0072] The liquid phase outlet pipeline at the bottom of the deethanizer 13 is provided with a regulating valve s119 for adjusting the liquid level at the bottom of the deethanizer 13.

[0073] The gas phase outlet pipeline at the top of the liquefied petroleum gas tower reflux tank 21 is provided with a regulating valve t120 for adjusting the pressure at the top of the liquefied petroleum gas tower 19.

[0074] The outlet pipeline of the LPG cooler 23 is provided with a regulating valve u121 for adjusting the liquid level at the bottom of the liquefied petroleum gas tower reflux tank 21.

[0075] The steam pipeline of the liquefied petroleum gas tower reboiler 24 is provided with a regulating valve v122 for adjusting the temperature at the bottom of the liquefied petroleum gas tower 19 .

[0076] The liquid phase outlet pipeline at the bottom of the liquefied petroleum gas tower 19 is provided with a regulating valve w123 for adjusting the liquid level at the bottom of the liquefied petroleum gas tower 19.

[0077] The outlet pipeline of the hydrogen-rich gas I channel A8 is provided with a regulating valve x124 for adjusting the pressure at the top of the dehydrogenation tower 6.

[0078] The outlet pipeline of the nitrogen-rich gas I channel A9 is provided with a regulating valve y125 for adjusting the pressure at the top of the LNG distillation tower 9.

[0079] The outlet pipeline of the raw gas III channel A5 is provided with a regulating valve z126.

[0080] The LNG distillation tower reboiler 12 can be internal or external.

[0081] The heat source of the deethanizer reboiler 17 and the liquefied petroleum gas tower reboiler 24 is steam.

[0082] The cold source of the liquefied petroleum gas tower condenser 20, the LPG cooler 23 and the condensate oil cooler 25 is circulating water.

[0083] The working principle of the device for producing LNG from high calorific value coal gas and co-producing LC2H6, LPG and condensate oil of the utility model comprises the following steps:

[0084] S1, after purification and removal of impurities (H2O and CO2), the coke oven gas containing hydrogen, carbon monoxide, methane, ethane, propane, butane, pentane, nitrogen, etc. is divided into two parts. One part is controlled by regulating valve a101 to control the flow rate of raw gas pipeline to adjust the temperature at the bottom of demethanizer 1, and the other part enters the bottom bypass pipe of demethanizer 1 to provide heat at the bottom of demethanizer, and then enters raw gas I channel A1, where it is cooled to ~-70°C by the reflux cold stream, and then enters heavy hydrocarbon separator 3 for gas-liquid separation. The liquid at the bottom is depressurized to ~1.7MPa.G by regulating valve b102 and then returns to the middle inlet of demethanizer 1, and the top gas phase returns to raw gas II channel A2 to continue cooling to ~-105 ℃; then enter the raw gas low-temperature separator 4 for gas-liquid separation, the liquid at the bottom is reduced in pressure to ~1.7MPa.G through the regulating valve c103 and then returned to the top inlet of the demethanizer 1, the top gas phase returns to the raw gas IV channel A6 and continues to cool to ~-162℃, and then enters the bottom of the dehydrogenation tower 6 for distillation separation; a stream of material is drawn out from the middle outlet of the demethanizer 1 and enters the hydrocarbon liquid channel A3 for heating, and then returns to the middle inlet of the demethanizer 1 to provide heat for the upper distillation of the demethanizer 1; the gas outlet at the top of the demethanizer 1 enters the raw gas III channel A5 and continues to cool to ~-135℃, and then reduces in pressure to ~0.62MPa.G through the regulating valve z126, and then enters the middle and upper part of the LNG distillation tower 9 for distillation;

[0085] S2, the low-temperature hydrogen-rich gas at the top outlet of the dehydrogenation tower 6 enters the hydrogen-rich IIIC1 channel and is cooled to -180--170°C, and then enters the dehydrogenation tower reflux tank 8 for gas-liquid separation, and the liquid at the bottom is returned to the top feed port of the dehydrogenation tower 6. The top hydrogen-rich gas enters the hydrogen-rich II channel B1 and the hydrogen-rich I channel A8 and is continuously heated to ~35°C, and then is sent to the hydrogen-rich pipeline outside the boundary through the regulating valve x124;

[0086] S3, the methane-rich liquid at the bottom of the dehydrogenation tower 6 is depressurized to ~0.62MPa.G through the regulating valve k111 and then enters the middle part of the LNG distillation tower 9 for distillation;

[0087] S4, after being rectified by the LNG distillation tower 9, nitrogen-rich gas is obtained at the top, cooled to -179°C in the nitrogen-rich gas III channel D1, and enters the LNG distillation tower reflux tank 11 for gas-liquid separation. The low-temperature liquid at the bottom returns to the top feed port of the LNG distillation tower 9. The top nitrogen-rich gas enters the nitrogen-rich gas II channel B2 and the nitrogen-rich gas I channel A9, and is continuously heated to -35°C. It is then depressurized to -0.5MPa.G through the regulating valve y125 and sent out of the device area. The LNG separated at the bottom of the LNG distillation tower 9 enters the LNG channel A4, is supercooled to -163°C, and is sent to the LNG storage tank through the regulating valve e105;

[0088] S5, Demethanizer 1 bottom C2 + After the liquid is depressurized to ~1.5MPa.G by the regulating valve d104, it is heated to ~65°C by the condensate heat exchanger 18 and the mixed hydrocarbons at the bottom of the deethanizer 13, and enters the middle part of the deethanizer 13 for distillation;

[0089] S6, after distillation in the deethanizer 13, ethane is obtained at the top, cooled to -15°C by the deethanizer condenser 14, and enters the deethanizer reflux tank 15 for gas-liquid separation. The bottom liquid is pressurized by the deethanizer liquid reflux pump 16 and then divided into two parts. One part of the liquid is refluxed to the top feed port of the deethanizer 13, and the other part of the liquid enters the ethane channel A7 and is cooled and supercooled to -90°C. After being depressurized to 0.02MPa.G by the regulating valve f106, it is sent to the LC2H6 storage tank, and the top gas phase is sent to the fuel gas pipeline network through the regulating valve p116. The steam amount of the deethanizer reboiler 17 is controlled by the regulating valve r118, thereby controlling the temperature of the deethanizer 13 bottom to -67°C;

[0090] S7, the mixed hydrocarbons at the bottom of the deethanizer 13 are cooled by the condensate heat exchanger 18, and then pressurized by the mixed hydrocarbon pump 30, and then sent to the middle of the liquefied petroleum gas tower 19 for distillation, and LPG is obtained at the top. It is cooled to 60-65°C by the liquefied petroleum gas tower condenser 20, and enters the liquefied petroleum gas tower reflux tank 21 for gas-liquid separation. The bottom liquid is pressurized by the liquefied petroleum gas tower liquid reflux pump 22 and is divided into two parts. One part of the liquid is refluxed to the top feed port of the liquefied petroleum gas tower 19, and the other part of the liquid enters the LPG cooler 23 and is cooled to 40°C. After passing through the regulating valve u121, it is sent to the LPG storage tank, and the top gas phase is sent to the fuel gas pipeline network through the regulating valve t120. The steam amount of the liquefied petroleum gas tower reboiler 24 is controlled by the regulating valve v122, thereby controlling the tower bottom temperature of the liquefied petroleum gas tower 19 to 135°C.

[0091] S8, the liquid at the bottom of the liquefied petroleum gas tower 19 is cooled to 40°C by the condensate cooler 25, and then sent to the condensate storage tank through the regulating valve w123;

[0092] S9. The condensation and liquefaction of the raw gas and nitrogen, the liquefaction and subcooling of LNG, and the liquefaction and subcooling of ethane are provided by the mixed refrigerant refrigeration cycle. First, the high-pressure liquid refrigerant from the mixed refrigerant compressor system 27 is subcooled to ~-60°C in the high-pressure liquid refrigerant channel IA14 of the main heat exchanger 2, and enters the inlet of the reflux refrigerant channel A12 after throttling and reducing the pressure through the regulating valve g107. The high-pressure gaseous refrigerant of the mixed refrigerant compressor system 27 is cooled to ~-60°C in the high-pressure gaseous refrigerant channel IA13 of the main heat exchanger 2, and then enters the refrigerant separator 28 for gas-liquid separation. The liquid separated at the bottom enters the high-pressure liquid refrigerant channel IIA16 and is subcooled to ~-124°C, and then enters the LNG distillation tower reboiler 12 after throttling and reducing the pressure through the regulating valve h108, which is the LNG distillation tower. The LNG distillation tower kettle 9 provides a heat source, and the LNG distillation tower reboiler 12 is provided with a bypass line. The temperature of the LNG distillation tower kettle 9 is controlled by the regulating valve m113, thereby controlling the CO content of the LNG in the LNG distillation tower kettle 9 to be lower than 0.5%, and the LNG is cooled to -145 to -100°C by the low-temperature liquid in the LNG distillation tower kettle 9, and enters the inlet of the reflux refrigerant channel A12; the high-pressure gas phase refrigerant from the top of the refrigerant separator 28 enters the high-pressure gas phase refrigerant channel IIA15 to be cooled and condensed to about -163°C, and enters the inlet of the reflux refrigerant channel A12 after throttling and reducing the pressure through the regulating valve i109. The mixed refrigerant entering the reflux refrigerant channel A12 absorbs heat and evaporates, and all evaporates into gas and is reheated to room temperature before exiting the main heat exchanger 2, and then returns to the mixed refrigerant compressor system 27 to complete the mixed refrigerant refrigeration cycle;

[0093] S10. The cryogenic separation of the raw gas is provided by the nitrogen cycle. First, the medium-pressure nitrogen from the nitrogen compression system 26 is cooled to about -162°C in the medium-pressure nitrogen I channel A10, and the nitrogen becomes liquid nitrogen. Then, it enters the medium-pressure liquid nitrogen I channel B3 and is supercooled to about -175°C. It is divided into three parts. The first part of the liquid nitrogen enters the reflux liquid nitrogen II channel C2 after throttling and reducing the pressure through the regulating valve j110, and controls the temperature of the hydrogen-rich gas entering the dehydrogenation tower reflux tank 8 to be between -179°C, providing a cold source for hydrogen separation at the top of the dehydrogenation tower 6; the second part of the liquid nitrogen is throttled and reduced in pressure through the regulating valve l112. After being compressed, it enters the reflux liquid nitrogen III channel D2, controls the temperature of the nitrogen-rich gas entering the LNG distillation tower reflux tank 11 to be between -179°C and -179°C, and provides a cold source for the separation of LNG at the top of the LNG distillation tower 9. After the third part of the liquid nitrogen is throttled and depressurized by the regulating valve n114, it merges with the liquid nitrogen refluxed from the reflux liquid nitrogen II channel C2 and the reflux liquid nitrogen III channel D2, enters the reflux liquid nitrogen I channel B4 to be reheated to -170°C, enters the reflux nitrogen I channel A11 to be reheated to room temperature, and then exits the main heat exchanger 2, and then returns to the inlet of the nitrogen compression system 26 to complete the nitrogen refrigeration cycle;

[0094] S11. The separation of ethane is provided with cooling capacity by the propane cycle. First, the liquid propane from the propane compression system 29 enters the deethanizer condenser 14 after throttling and reducing the pressure through the regulating valve o115. The temperature of ethane entering the deethanizer reflux tank 15 is controlled to be between -15°C and the liquid propane is throttled and reduced in pressure, evaporated and gasified into gaseous propane, and then returns to the inlet of the propane compression system 29 to complete the propane refrigeration cycle.

[0095] This embodiment can be implemented according to the parameters of the purified raw gas in the following table, and the parameters and components of the obtained hydrogen-rich gas, nitrogen-rich gas, LNG, LC2H6, LPG and condensate oil are shown in Table 1 below:

[0096] Table 1 Parameters and components of Example 1

[0097]

[0098] Embodiment 2: When the liquefied petroleum gas tower 19 is under maintenance or abnormal, the dehydrogenation tower 6 and the LNG distillation tower 9 can be used to produce LNG, and the deethanizer 13 can be used to produce LC2H6. At this time, the flow path is that the raw gas is divided into two parts, one part controls the raw gas pipeline flow through the regulating valve a101 to adjust the temperature at the bottom of the demethanizer 1, and the other part enters the bottom of the demethanizer 1 to bypass the pipe, providing heat to the bottom of the demethanizer, and then enters the raw gas I channel A1, where it is cooled and partially condensed by the reflux cold stream, and then enters the heavy hydrocarbon separator 3 for gas-liquid separation. The liquid at the bottom is returned to the middle inlet of the demethanizer 1 through the regulating valve b102 to control the amount of heavy hydrocarbons, and the top gas phase returns to the raw gas II Channel A2 continues to cool; then enters the raw gas low-temperature separator 4 for gas-liquid separation, the liquid at the bottom is returned to the top inlet of the demethanizer 1 through the regulating valve c103 to control the amount of condensate, and the top gas phase returns to the raw gas IV channel A6 to continue cooling to ~-162°C, and then enters the bottom of the dehydrogenation tower 6 for distillation separation; a stream of material is drawn out from the middle outlet of the demethanizer 1 and enters the hydrocarbon liquid channel A3 for heating, and then returns to the middle inlet of the demethanizer 1 to provide heat for the upper distillation of the demethanizer 1; the top gas outlet of the demethanizer 1 enters the raw gas III channel A5 and continues to cool to ~-135°C, and then is reduced in pressure to ~0.62MPa.G through the regulating valve z126, and then enters the middle and upper part of the LNG distillation tower 9 for distillation. The low-temperature hydrogen-rich gas at the top outlet of the dehydrogenation tower 6 enters the hydrogen-rich IIIC1 channel and is cooled to ~-179°C, and then enters the dehydrogenation tower reflux tank 8 for gas-liquid separation. The liquid at the bottom returns to the top feed port of the dehydrogenation tower 6. The top hydrogen-rich gas enters the hydrogen-rich II channel B1 and the hydrogen-rich I channel A8 and is continuously heated to ~35°C, and then is sent to the hydrogen-rich pipeline outside the boundary through the regulating valve x124. The methane-rich liquid at the bottom of the dehydrogenation tower 6 is reduced in pressure to ~0.62MPa.G through the regulating valve k111 and then enters the middle part of the LNG distillation tower 9 for distillation, and the rest is carried out according to the steps of Example 1. Demethanizer 1 Bottom C2 +After the liquid is depressurized to ~1.5MPa.G through the regulating valve d104, it is heated to 60-65°C through the condensate heat exchanger 18 and the mixed hydrocarbon at the bottom of the deethanizer 13, and enters the middle of the deethanizer 13 for distillation. After distillation in the deethanizer 13, ethane is obtained at the top, cooled to ~-15°C through the deethanizer condenser 14, and enters the deethanizer reflux tank 15 for gas-liquid separation. The bottom liquid is pressurized by the deethanizer liquid reflux pump 16 and divided into two parts. One part of the liquid is refluxed to the top feed port of the deethanizer 13, and the other part of the liquid enters the ethane channel A7, is cooled and supercooled to -90°C, and then is depressurized to 0.02MPa.G through the regulating valve f106 and sent to the LC2H6 storage tank. The top gas phase is sent to the fuel gas pipeline network through the regulating valve p116. The steam volume of the deethanizer reboiler 17 is controlled by regulating valve r118, thereby controlling the temperature of the deethanizer 13 bottom to 67°C, and the rest is carried out according to the steps of Example 1. At this time, the liquefied petroleum gas tower 19 is not working, and the mixed hydrocarbons at the bottom of the deethanizer 13 are cooled by the condensate heat exchanger 18, and then pressurized by the mixed hydrocarbon pump 30 and directly sent to the unqualified product storage tank outside the boundary.

[0099] This embodiment can be implemented according to the parameters of the purified raw gas in the table below. The parameters and components of the obtained hydrogen-rich gas, nitrogen-rich gas, LNG, LC2H6 and mixed hydrocarbons are shown in Table 1 below:

[0100] Example 2 Parameters and components

[0101]

[0102] The utility model is described in detail above with reference to the accompanying drawings and embodiments, but the utility model is not limited to the above embodiments, and various changes can be made within the scope of ordinary technicians in the field without departing from the purpose of the utility model. Therefore, the utility model is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope of protection of the utility model.

Claims

1. A device for producing LNG from high calorific value coal gas and co-producing LC2H6, LPG and condensate oil, characterized in that: The device comprises a demethanizer (1), a main heat exchanger (2), a heavy hydrocarbon separator (3), a raw gas low-temperature separator (4), a subcooler (5), a dehydrogenation tower (6), a dehydrogenation tower condenser (7), a dehydrogenation tower reflux tank (8), an LNG distillation tower (9), an LNG distillation tower condenser (10), an LNG distillation tower reflux tank (11), an LNG distillation tower reboiler (12), a deethanizer (13), a deethanizer condenser (14), a deethanizer reflux tank (15), a deethanizer liquid reflux pump (16), a deethanizer reboiler (17), a condensate heat exchanger (18), a liquefied petroleum gas tower (19), a liquefied petroleum gas tower condenser (20), a liquefied petroleum gas tower reflux tank (21), a liquefied petroleum gas tower A liquid reflux pump (22), an LPG cooler (23), a liquefied petroleum gas tower reboiler (24), a condensate cooler (25), a nitrogen compression system (26), a mixed refrigerant compressor system (27), a refrigerant separator (28), a propane compressor system (29), and a mixed hydrocarbon booster pump (30). The main heat exchanger is provided with a raw gas I channel (A1), a raw gas II channel (A2), a hydrocarbon liquid channel (A3), an LNG channel (A4), a raw gas III channel (A5), a raw gas IV channel (A6), an ethane channel (A7), a hydrogen-rich gas I channel (A8), a nitrogen-rich gas I channel (A9), a medium-pressure nitrogen I channel (A10), a reflux nitrogen I channel (A11), and a reflux refrigerant channel (A12). A12), high-pressure gas phase refrigerant channel I (A13), high-pressure liquid phase refrigerant channel I (A14), high-pressure gas phase refrigerant channel II (A15), high-pressure liquid phase refrigerant channel II (A16); the subcooler (5) is provided with a hydrogen-rich gas II channel (B1), a nitrogen-rich gas II channel (B2), a medium-pressure liquid nitrogen I channel (B3), and a reflux liquid nitrogen I channel (B4); the dehydrogenation tower condenser (7) is provided with a hydrogen-rich gas III (C1) and a reflux liquid nitrogen II channel (C2); the LNG distillation tower condenser (10) is provided with a nitrogen-rich gas III channel (D1) and a reflux liquid nitrogen III channel (D2); the raw gas after external purification is divided into two paths, one of which is fed to the demethanizer (1) feed gas. The outlet of the demethanizer (1) is connected to the inlet of the raw gas channel I (A1), the outlet of the raw gas channel I (A1) is connected to the feed inlet of the heavy hydrocarbon separator (3), the bottom liquid phase outlet of the heavy hydrocarbon separator (3) is connected to the inlet of the demethanizer (1), the top gas phase outlet of the heavy hydrocarbon separator (3) is connected to the inlet of the raw gas channel II (A2), the outlet of the raw gas channel II (A2) is connected to the feed inlet of the raw gas low-temperature separator (4), the bottom liquid phase outlet of the raw gas low-temperature separator (4) is connected to the inlet of the demethanizer (1), and the top gas phase outlet of the raw gas low-temperature separator (4) is connected to the inlet of the raw gas channel IV (A6).The outlet of the raw gas IV channel (A6) is connected to the feed port of the dehydrogenation tower (6), the middle outlet of the demethanizer (1) is connected to the inlet of the hydrocarbon liquid channel (A3), the outlet of the hydrocarbon liquid channel (A3) is connected to the middle inlet of the demethanizer (1), the bottom liquid phase outlet of the demethanizer (1) is connected to the condensate inlet of the condensate heat exchanger (18), the condensate outlet of the condensate heat exchanger (18) is connected to the feed port of the deethanizer (13), the top gas phase outlet of the demethanizer (1) is connected to the inlet of the raw gas III channel (A5), the outlet of the raw gas III channel (A5) is connected to the feed port of the LNG distillation tower (9), the bottom liquid phase outlet of the dehydrogenation tower (6) is connected to the LNG distillation tower (9 ) feed port, the gas phase outlet at the top of the dehydrogenation tower (6) is connected to the inlet of the hydrogen-rich gas III (C1), the outlet of the hydrogen-rich gas III (C1) is connected to the feed port of the dehydrogenation tower reflux tank (8), the liquid phase outlet at the bottom of the dehydrogenation tower reflux tank (8) is connected to the feed port of the dehydrogenation tower (6), the gas phase outlet at the top of the dehydrogenation tower reflux tank (8) is connected to the inlet of the hydrogen-rich gas II channel (B1), the outlet of the hydrogen-rich gas II channel (B1) is connected to the inlet of the hydrogen-rich gas I channel (A8), the outlet of the hydrogen-rich gas I channel (A8) is connected to the external hydrogen-rich gas pipeline, the liquid phase outlet at the bottom of the LNG distillation tower (9) is connected to the inlet of the LNG channel (A4), and the outlet of the LNG channel (A4) is connected to the external The LNG is connected to the LNG storage tank pipeline, the gas phase outlet at the top of the LNG distillation tower (9) is connected to the inlet of the nitrogen-rich gas III channel (D1), the outlet of the nitrogen-rich gas III channel (D1) is connected to the feed port of the LNG distillation tower reflux tank (11), the liquid phase outlet at the bottom of the LNG distillation tower reflux tank (11) is connected to the feed port of the LNG distillation tower (9), the gas phase outlet at the top of the LNG distillation tower reflux tank (11) is connected to the inlet of the nitrogen-rich gas II channel (B2), the outlet of the nitrogen-rich gas II channel (B2) is connected to the inlet of the nitrogen-rich gas I channel (A9), the outlet of the nitrogen-rich gas I channel (A9) is connected to the external nitrogen-rich tail gas pipeline, the liquid phase outlet at the bottom of the deethanizer (13) is connected to the condensate exchange The mixed hydrocarbon inlet of the condensate heat exchanger (18) is connected to the mixed hydrocarbon outlet of the condensate heat exchanger (18) is connected to the inlet of the mixed hydrocarbon booster pump (30), the outlet of the mixed hydrocarbon booster pump (30) is connected to the feed inlet of the liquefied petroleum gas tower (19), the gas phase outlet at the top of the deethanizer (13) is connected to the ethane inlet of the deethanizer condenser (14), the ethane outlet of the deethanizer condenser (14) is connected to the feed inlet of the deethanizer reflux tank (15), the gas phase outlet at the top of the deethanizer reflux tank (15) is connected to the off-site fuel gas pipeline, the liquid phase outlet at the bottom of the deethanizer reflux tank (15) is connected to the inlet of the deethanizer liquid reflux pump (16), and the outlet of the deethanizer liquid reflux pump (16) is divided into two parts.One part is connected to the inlet of the deethanizer (13), and the other part is connected to the inlet of the ethane channel (A7). The outlet of the ethane channel (A7) is connected to the pipeline of the liquid ethane to the LC2H6 storage tank outside the boundary. The outlet of the deethanizer (13) is connected to the mixed hydrocarbon inlet of the deethanizer reboiler (17). The mixed hydrocarbon outlet of the deethanizer reboiler (17) is connected to the inlet of the deethanizer (13). The liquid phase outlet at the bottom of the liquefied petroleum gas tower (19) is connected to the condensate inlet of the condensate cooler (25). The condensate outlet of the condensate cooler (25) is connected to the pipeline of the condensate to the condensate storage tank outside the boundary. The gas phase outlet at the top of the liquefied petroleum gas tower (19) is connected to the condenser (20) of the liquefied petroleum gas tower. The LPG inlet of the liquefied petroleum gas tower condenser (20) is connected to the feed inlet of the liquefied petroleum gas tower reflux tank (21), the gas phase outlet at the top of the liquefied petroleum gas tower reflux tank (21) is connected to the fuel gas pipeline outside the boundary, the liquid phase outlet at the bottom of the liquefied petroleum gas tower reflux tank (21) is connected to the inlet of the liquefied petroleum gas tower liquid reflux pump (22), the outlet of the liquefied petroleum gas tower liquid reflux pump (22) is divided into two parts, one part is connected to the inlet of the liquefied petroleum gas tower (19), and the other part is connected to the LPG inlet of the LPG cooler (23), the LPG outlet of the LPG cooler (23) is connected to the LPG pipeline outside the boundary to the LPG storage tank, the liquefied petroleum gas tower ( The outlet of the medium-pressure nitrogen channel (A10) is connected to the outlet of the nitrogen compression system (26). The outlet of the medium-pressure nitrogen channel (A10) is connected to the inlet of the medium-pressure liquid nitrogen channel (B3). The outlet of the medium-pressure liquid nitrogen channel (B3) is connected to the inlet of the reflux liquid nitrogen channel (C2) and the inlet of the reflux liquid nitrogen channel (D2). The inlet of the reflux liquid nitrogen channel (B4) is connected to the outlet of the reflux liquid nitrogen channel (C2) and the outlet of the reflux liquid nitrogen channel (D2). The outlet of the high-pressure refrigerant channel B4 is connected to the inlet of the reflux nitrogen channel I (A11), the outlet of the reflux nitrogen channel I (A11) is connected to the inlet of the nitrogen compression system (26), the inlet of the high-pressure liquid phase refrigerant channel I (A14) is connected to the liquid phase outlet of the mixed refrigerant compressor system (27), the outlet of the high-pressure liquid phase refrigerant channel I (A14) is connected to the inlet of the reflux refrigerant channel (A12), the inlet of the high-pressure gas phase refrigerant channel I (A13) is connected to the gas phase outlet of the mixed refrigerant compressor system (27), the outlet of the high-pressure gas phase refrigerant channel I (A13) is connected to the feed port of the refrigerant separator (28), and the gas phase outlet of the refrigerant separator (28) is connected to the inlet of the high-pressure gas phase refrigerant channel II (A15),The outlet of the high-pressure gas phase refrigerant channel II (A15) is connected to the inlet of the reflux refrigerant channel (A12), the liquid phase outlet of the refrigerant separator (28) is connected to the inlet of the high-pressure liquid phase refrigerant channel II (A16), the outlet of the high-pressure liquid phase refrigerant channel II (A16) is connected to the refrigerant inlet of the LNG distillation tower reboiler (12), the refrigerant outlet of the LNG distillation tower reboiler (12) is connected to the inlet of the reflux refrigerant channel (A12), the outlet of the reflux refrigerant channel (A12) is connected to the inlet of the mixed refrigerant compressor system (27), the propane inlet of the deethanizer condenser (14) is connected to the outlet of the propane compressor system (29), and the propane outlet of the deethanizer condenser (14) is connected to the inlet of the propane compressor system (29).

2. The device for producing LNG from high calorific value coal gas and co-producing LC2H6, LPG and condensate according to claim 1, characterized in that: The demethanizer (1), dehydrogenator (6), LNG distillation tower (9), deethanizer (13) and liquefied petroleum gas tower (19) are packed towers or plate towers.

3. The device for producing LNG from high calorific value coal gas and co-producing LC2H6, LPG and condensate according to claim 1, characterized in that: The raw gas pipeline is provided with a regulating valve a (101) for regulating the temperature at the bottom of the demethanizer (1); the liquid phase outlet pipeline at the bottom of the heavy hydrocarbon separator (3) is provided with a regulating valve b (102) for regulating the liquid level at the bottom of the heavy hydrocarbon separator (3); the liquid phase outlet pipeline at the bottom of the raw gas low-temperature separator (4) is provided with a regulating valve c (103) for regulating the liquid level at the bottom of the raw gas low-temperature separator (4); the liquid phase outlet pipeline at the bottom of the demethanizer (1) is provided with a regulating valve d (104) for regulating the liquid level at the bottom of the demethanizer (1); the pipeline at the outlet of the LNG channel (A4) is provided with a regulating valve e (105) for regulating the liquid level at the bottom of the LNG distillation tower (9); the ethane channel (A The outlet pipeline of the deethanizer (7) is provided with a regulating valve f (106) for regulating the liquid level at the bottom of the deethanizer reflux tank (15); the outlet pipeline of the high-pressure liquid phase refrigerant channel I (A14) is provided with a regulating valve g (107); the outlet pipeline of the high-pressure liquid phase refrigerant channel II (A16) is provided with a regulating valve h (108); the outlet pipeline of the high-pressure gas phase refrigerant channel II (A15) is provided with a regulating valve i (109); the inlet pipeline of the reflux liquid nitrogen II channel (C2) is provided with a regulating valve j (110) for regulating the temperature of the outlet of the hydrogen-rich gas III (C1); the outlet pipeline of the liquid phase at the bottom of the dehydrogenation tower (6) is provided with a regulating valve k (111) for regulating the liquid level at the bottom of the dehydrogenation tower (6); the reflux liquid The nitrogen III channel (D2) inlet pipeline is provided with a regulating valve l (112) for regulating the temperature of the nitrogen-rich gas III channel (D1) outlet; the bypass pipeline of the LNG distillation tower reboiler (12) is provided with a regulating valve m (113) for regulating the temperature at the bottom of the LNG distillation tower (9); the bypass pipelines of the medium-pressure liquid nitrogen and reflux liquid nitrogen are provided with regulating valve n (114); the propane inlet pipeline of the deethanizer condenser (14) is provided with a regulating valve o (115) for regulating the temperature at the top of the deethanizer (13); the gas phase outlet pipeline at the top of the deethanizer reflux tank (15) is provided with a regulating valve p (116) for regulating the pressure at the top of the deethanizer (13); the deethanizer reboiler (17 ) is provided with a regulating valve r (118) for regulating the temperature at the bottom of the deethanizer (13); the liquid phase outlet pipeline at the bottom of the deethanizer (13) is provided with a regulating valve s (119) for regulating the liquid level at the bottom of the deethanizer (13); the gas phase outlet pipeline at the top of the liquefied petroleum gas tower reflux tank (21) is provided with a regulating valve t (120) for regulating the pressure at the top of the liquefied petroleum gas tower (19); the outlet pipeline of the LPG cooler (23) is provided with a regulating valve u (121) for regulating the liquid level at the bottom of the liquefied petroleum gas tower reflux tank (21); the steam pipeline of the liquefied petroleum gas tower reboiler (24) is provided with a regulating valve v (122) for regulating the temperature at the bottom of the liquefied petroleum gas tower (19);The liquid phase outlet pipeline at the bottom of the liquefied petroleum gas tower (19) is provided with a regulating valve w (123) for regulating the liquid level at the bottom of the liquefied petroleum gas tower (19); the outlet pipeline of the hydrogen-rich gas I channel (A8) is provided with a regulating valve x (124) for regulating the pressure at the top of the dehydrogenation tower (6); the outlet pipeline of the nitrogen-rich gas I channel (A9) is provided with a regulating valve y (125) for regulating the pressure at the top of the LNG distillation tower (9).

4. The device for producing LNG from high calorific value coal gas and co-producing LC2H6, LPG and condensate according to claim 1, characterized in that: The LNG distillation tower reboiler (12) can be internal or external.

5. The device for producing LNG from high calorific value coal gas and co-producing LC2H6, LPG and condensate according to claim 1, characterized in that: The heat source of the deethanizer reboiler (17) and the liquefied petroleum gas tower reboiler (24) is steam.

6. The device for producing LNG from high calorific value coal gas and co-producing LC2H6, LPG and condensate according to claim 1, characterized in that: The cold sources of the liquefied petroleum gas tower condenser (20), the LPG cooler (23) and the condensate oil cooler (25) are circulating water.

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