Pyrolysis gas recovery equipment

Abstract

The utility model discloses pyrolysis gas recovery equipment, and belongs to the technical field of coal chemical industry. The pyrolysis gas recovery equipment comprises a cold box, a heavy contact tower, a methane and ethane removal tower, a liquefied gas tower, a dehydrogenation device and a decarburization device, and the cold box is provided with a gas cooling channel, a heavy hydrocarbon cooling channel and a gas cooling channel. The heavy contact tower is provided with a first inlet communicated with the coal gas cooling channel, a first liquid phase outlet communicated with the heavy hydrocarbon cooling channel and a first gas phase outlet communicated with the inlet end of the gas cooling channel; the methane and ethane removal tower is provided with a second inlet and a second liquid phase outlet which are communicated with the heavy hydrocarbon cooling channel of the cold box; the liquefied gas tower is provided with a third inlet communicated with the second liquid phase outlet, a third liquid phase outlet through which light hydrocarbon substances flow out and a third gas phase outlet through which LPG (Liquefied Petroleum Gas) flows out; the dehydrogenation device is provided with a dehydrogenation inlet, a hydrogen outlet and a first LNG outlet, and the dehydrogenation inlet communicates with the gas cooling channel; the decarburization device is provided with a decarburization inlet and a second LNG outlet, and the decarburization inlet communicates with the first LNG outlet.

Description

Technical Field

[0001] The present application belongs to the field of coal chemical technology, and specifically relates to a pyrolysis coal gas recovery device. Background Art

[0002] A large amount of coal gas is produced during the processing and use of coal, which contains a large amount of usable resources and harmful components. Extensive use of coal gas will not only cause environmental pollution, but also cause a huge waste of energy.

[0003] In the field of modern coal chemical industry, the clean and efficient conversion and utilization of coal by quality separation is mainly based on the material composition and physical and chemical properties of low-priced coal, and the coal is pyrolyzed into gas, liquid and solid three-phase substances by medium and low temperature pyrolysis technology. Pyrolysis coal gas is the gas phase part, and the hydrogen content of pyrolysis coal gas exceeds 20%, the methane content exceeds 40%, and the C2-C3 content reaches 14%.

[0004] At present, the recovery and processing technology of pyrolysis gas mainly utilizes cryogenic separation technology and multi-stage distillation to prepare LNG (Liquefied Natural Gas) products and co-produce LPG (Liquefied Petroleum Gas) products, but the recovery rate of pyrolysis gas needs to be improved. Utility Model Content

[0005] The purpose of the embodiment of the present application is to provide a pyrolysis gas recovery device that can solve the problem of low recovery rate of pyrolysis gas in related technologies.

[0006] The present application provides a pyrolysis gas recovery device, comprising:

[0007] A cold box, wherein the cold box is provided with a coal gas cooling channel, a heavy hydrocarbon cooling channel and a gas cooling channel, wherein the coal gas cooling channel is used for circulating the pyrolysis coal gas;

[0008] A heavy contact tower, wherein the heavy contact tower is provided with a first inlet, a first liquid phase outlet and a first gas phase outlet, wherein the first inlet is communicated with the outlet end of the coal gas cooling channel, the first liquid phase outlet is communicated with the inlet end of the heavy hydrocarbon cooling channel, and the first gas phase outlet is communicated with the inlet end of the gas cooling channel;

[0009] A demethylethane tower, wherein the demethylethane tower is provided with a second inlet and a second liquid phase outlet, and the outlet end of the heavy hydrocarbon cooling channel of the cold box is connected to the second inlet;

[0010] A liquefied gas tower, wherein the liquefied gas tower is provided with a third inlet, a third liquid phase outlet and a third gas phase outlet, wherein the third inlet is connected to the second liquid phase outlet, the third gas phase outlet is used for LPG to flow out, and the third liquid phase outlet is used for light hydrocarbon substances to flow out;

[0011] A dehydrogenation device, wherein the dehydrogenation device is provided with a dehydrogenation inlet, a hydrogen outlet and a first LNG outlet, wherein the dehydrogenation inlet is communicated with the outlet end of the gas cooling channel, and the hydrogen outlet is used for discharging hydrogen;

[0012] The decarbonization device is provided with a decarbonization inlet and a second LNG outlet, wherein the decarbonization inlet is connected to the first LNG outlet, and the second LNG outlet is used for LNG to flow out.

[0013] In the embodiment of the present application, the pyrolysis gas is refined by using a heavy contact tower, and the heavy hydrocarbons in the pyrolysis gas are formed into liquefied petroleum gas products (i.e., LPG products) and stable light hydrocarbon products through a demethylation and ethane removal tower and a liquefied gas tower. At the same time, the refined gas mainly contains light components such as methane, ethane, and propane. The gas is successively dehydrogenated by a dehydrogenation device and decarbonized by a decarbonization device to form a liquefied natural gas product (i.e., LNG product), and hydrogen is generated during the dehydrogenation process. Therefore, the pyrolysis gas recovery process of the present application can not only prepare LNG products and co-produce LPG products, but also prepare stable light hydrocarbon products and hydrogen, increase the types of available resources, and improve the recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the pyrolysis gas recovery equipment disclosed in the embodiment of the present application;

[0015] Figure 2 It is a schematic diagram of the structure of the pyrolysis gas recovery equipment disclosed in the embodiment of the present application for producing LPG products and light hydrocarbon products;

[0016] Figure 3 It is a schematic diagram of the structure of the pyrolysis gas recovery equipment disclosed in the embodiment of the present application for producing hydrogen and LNG products;

[0017] Figure 4 It is a schematic diagram of the structure of the dehydrogenation device disclosed in the embodiment of the present application;

[0018] Figure 5 It is a schematic diagram of the structure of the decarbonization device disclosed in the embodiment of the present application;

[0019] Figure 6 It is a schematic diagram of the structure of the cold box disclosed in the embodiment of the present application;

[0020] Figure 7 It is a structural schematic diagram of the pyrolysis gas recovery equipment and various refrigeration devices disclosed in the embodiments of the present application.

[0021] Description of reference numerals:

[0022] 100-cold box, 110-coal gas cooling channel, 120-heavy hydrocarbon cooling channel, 130-gas cooling channel, 131-third cooling channel, 132-fourth cooling channel, 140-methyl ethane cooling channel, 141-first cooling channel, 142-second cooling channel, 150-first LNG cooling channel, 160-second LNG cooling channel, 170-hydrogen cooling channel, 180-carbon gas cooling channel,

[0023] 210- low temperature separator,

[0024] 220-recontact tower, 221-first inlet, 222-first liquid phase outlet, 223-first gas phase outlet, 224-first washing liquid inlet,

[0025] 230-Heavy hydrocarbon reflux pump,

[0026] 310-demethylethane tower, 311-second inlet, 312-second liquid phase outlet, 313-second gas phase outlet, 320-demethylethane separator,

[0027] 330-Demethylation ethane reflux pump,

[0028] 340-Demethylation Ethane Reboiler,

[0029] 410-liquefied gas tower, 411-third inlet, 412-third liquid phase outlet, 413-third gas phase outlet,

[0030] 420-liquefied gas cooler,

[0031] 430-Liquefied gas separator,

[0032] 440-liquefied gas reflux pump,

[0033] 450-Light hydrocarbon cooler,

[0034] 460-Liquefied gas reboiler,

[0035] 500-Dehydrogenation unit,

[0036] 510-dehydrogenation tower, 511-dehydrogenation inlet, 512-first LNG outlet, 513-fourth gas phase outlet, 514-second washing liquid inlet, 515-dehydrogenation cooling capacity inlet,

[0037] 520-Dehydrogenation Cooler,

[0038] 530-dehydrogenation separator, 531-hydrogen outlet,

[0039] 600-Decarbonization device,

[0040] 610-decarbonization tower, 611-decarbonization inlet, 612-second LNG outlet, 613-fifth gas phase outlet, 614-third washing liquid inlet, 615-decarbonization cooling inlet,

[0041] 620-Decarbonization cooler,

[0042] 630-decarbonization separator, 631-carbon gas outlet,

[0043] 640-Decarbonization reboiler,

[0044] 700-LNG storage tank,

[0045] 810-volatile gas blower, 820-volatile gas reheater, 830-volatile gas cooler,

[0046] 910-Nitrogen compressor unit, 920-Mixed refrigerant compressor unit, 930-Propane compressor unit. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0048] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0049] The pyrolysis gas recovery equipment provided in the embodiment of the present application is described in detail below through specific embodiments and their application scenarios in conjunction with the accompanying drawings.

[0050] Please refer to Figure 1-Figure 7 The pyrolysis gas recovery equipment disclosed in the embodiment of the present application includes a cold box 100, a heavy contact tower 220, a demethylation and ethane removal tower 310, a liquefied gas tower 410, a dehydrogenation device 500 and a decarbonization device 600.

[0051] The cold box 100 is used to provide cold capacity to cool the materials at various stages in the pyrolysis gas recovery process. The cold box 100 is provided with a gas cooling channel 110, a heavy hydrocarbon cooling channel 120 and a gas cooling channel 130. The gas cooling channel 110 is used to allow the pyrolysis gas to circulate so as to cool the pyrolysis gas; the heavy hydrocarbon cooling channel 120 is used to cool the heavy hydrocarbon materials removed by the heavy contact tower 220; and the gas cooling channel 130 is used to cool the light components removed by the demethylation and ethane tower 310.

[0052] The heavy contact tower 220, namely the DHX tower, is a device for treating gas. The heavy contact tower 220 is used to remove hydrocarbon substances such as methane, ethane, propane, etc. from the pyrolysis coal gas. Figure 1 and Figure 2 As shown, the heavy contact tower 220 is provided with a first inlet 221, a first liquid phase outlet 222 and a first gas phase outlet 223. The first inlet 221 is connected to the outlet end of the coal gas cooling channel 110, so the pyrolysis coal gas enters the heavy contact tower 220 from the first inlet 221 after being cooled through the coal gas cooling channel 110, and undergoes a light component distillation process. The heavy hydrocarbon substances after distillation flow out from the first liquid phase outlet 222, and the removed light components such as methane, ethane, and propane flow out from the first gas phase outlet 223. Moreover, the first liquid phase outlet 222 is connected to the inlet end of the heavy hydrocarbon cooling channel 120, and the first gas phase outlet 223 is connected to the inlet end of the gas cooling channel 130, so the heavy hydrocarbon substances enter the heavy hydrocarbon cooling channel 120 for reheating, and the removed light components such as methane, ethane, and propane enter the gas cooling channel 130 for cooling.

[0053] Optionally, the pyrolysis coal gas recovery device further includes a heavy hydrocarbon reflux pump 230, the inlet end of the heavy hydrocarbon reflux pump 230 is connected to the first liquid phase outlet 222, and the outlet end of the heavy hydrocarbon reflux pump 230 is connected to the heavy hydrocarbon cooling channel 120. That is, the heavy hydrocarbon material after distillation in the heavy contact tower 220 is pumped into the heavy hydrocarbon cooling channel 120 under the pressure of the heavy hydrocarbon reflux pump 230.

[0054] The demethylbenzene tower 310 is used to remove methane and ethane from the heavy hydrocarbon material. The demethylbenzene tower 310 is provided with a second inlet 311 and a second liquid phase outlet 312. The outlet end of the heavy hydrocarbon cooling channel 120 of the cold box 100 is connected to the second inlet 311, that is, the heavy hydrocarbon material after distillation in the heavy contact tower 220 enters the demethylbenzene tower 310 through the second inlet 311 after reheating, and the methane and ethane after distillation flow out from the top of the tower, and the remaining heavy hydrocarbon components flow out from the second liquid phase outlet 312. Optionally, a demethylbenzene reboiler 340 is provided at the bottom of the demethylbenzene tower 310, and the material entering the demethylbenzene tower 310 is distilled under the action of the demethylbenzene reboiler 340.

[0055] The liquefied gas tower 410 is used to further rectify the heavy hydrocarbon components after rectification in the demethylated ethane tower 310. The liquefied gas tower 410 is provided with a third inlet 411, a third liquid phase outlet 412 and a third gas phase outlet 413. The third inlet 411 is connected to the second liquid phase outlet 312. The third gas phase outlet 413 is used for LPG to flow out, and the third liquid phase outlet 412 is used for light hydrocarbon substances to flow out. That is, the heavy hydrocarbon components after rectification in the demethylated ethane tower 310 enter the liquefied gas tower 410 through the third inlet 411. After further rectification in the liquefied gas tower 410, the gas component LPG flows out from the third gas phase outlet 413 at the top of the liquefied gas tower 410, and the light hydrocarbon substances flow out from the third liquid phase outlet 412 at the bottom of the liquefied gas tower 410.

[0056] Optionally, the pyrolysis coal gas recovery equipment further includes a liquefied gas cooler 420 and a liquefied gas separator 430, wherein the inlet end of the liquefied gas cooler 420 is connected to the third gas phase outlet 413, the outlet end of the liquefied gas cooler 420 is connected to the inlet end of the liquefied gas separator 430, and the liquid phase outlet end of the liquefied gas separator 430 is connected to the washing liquid inlet of the liquefied gas tower 410. After the LPG flowing out of the third gas phase outlet 413 is cooled and separated in sequence, the separated gas phase is discharged into the atmosphere, a part of the liquid phase is returned to the liquefied gas tower 410 as the washing liquid of the liquefied gas tower 410, and the other part is the LPG product. Among them, the liquefied gas cooler 420 cools the LPG to 40°C.

[0057] Further optionally, the pyrolysis coal gas recovery equipment further includes a liquefied gas reflux pump 440, the inlet end of the liquefied gas reflux pump 440 is connected to the liquid phase outlet end of the liquefied gas separator 430, and the outlet end of the liquefied gas reflux pump 440 is connected to the washing liquid inlet of the liquefied gas tower 410. In this way, a part of the liquid phase separated by the liquefied gas separator 430 is pumped into the liquefied gas tower 410 under the pressurization of the liquefied gas reflux pump 440.

[0058] refer to Figure 3 and Figure 4 As shown, the dehydrogenation device 500 is used to dehydrogenate the methane and ethane light components removed by the demethylation ethane tower 310. The dehydrogenation device 500 is provided with a dehydrogenation inlet 511, a hydrogen outlet 531 and a first LNG outlet 512. The dehydrogenation inlet 511 is connected to the outlet end of the gas cooling channel 130, and the hydrogen outlet 531 is used to discharge hydrogen. That is, the methane and ethane removed by the demethylation ethane tower 310 are cooled by the gas cooling channel 130 and then enter the dehydrogenation device 500 for dehydrogenation, and the LNG after dehydrogenation flows out from the first LNG outlet 512.

[0059] refer to Figure 3 and Figure 5As shown, the decarbonization device 600 is used to further decarbonize the light components after dehydrogenation. The decarbonization device 600 is provided with a decarbonization inlet 611 and a second LNG outlet 612, the decarbonization inlet 611 is connected to the first LNG outlet 512, and the second LNG outlet 612 is used for LNG to flow out. That is, the LNG after dehydrogenation enters the decarbonization device 600 from the decarbonization inlet 611, and the LNG after decarbonization flows out from the second LNG outlet 612. The decarbonization device 600 is also provided with a carbon gas outlet 631, and the carbon gas outlet 631 is used to discharge the removed carbon gas.

[0060] In the embodiment of the present application, the heavy contact tower 220 is used to refine the pyrolysis gas, and the heavy hydrocarbons in the pyrolysis gas are formed into liquefied petroleum gas products (i.e., LPG products) and stable light hydrocarbon products through the demethylation and ethane tower 310 and the liquefied gas tower 410. At the same time, the refined gas mainly contains light components such as methane, ethane, and propane. The gas is successively dehydrogenated by the dehydrogenation device 500 and decarbonized by the decarbonization device 600 to form a liquefied natural gas product (i.e., LNG product), and hydrogen is generated during the dehydrogenation process. Therefore, the pyrolysis gas recovery process of the present application can not only prepare LNG products and co-produce LPG products, but also prepare stable light hydrocarbon products and hydrogen, increase the types of available resources, and improve the recovery rate.

[0061] Optionally, the pyrolysis coal gas is pre-cooled to -72°C through the coal gas cooling channel 110 , and the heavy hydrocarbons after distillation in the heavy contact tower 220 are reheated to 15°C through the heavy hydrocarbon cooling channel 120 and then enter the demethylation ethane tower 310 .

[0062] In an optional embodiment, if Figure 1-Figure 2 as well as Figure 7 As shown, the demethylethane tower 310 is provided with a second gas phase outlet 313, the cold box 100 is further provided with a methylethane cooling channel 140, the inlet end of the methylethane cooling channel 140 is communicated with the second gas phase outlet 313, and the re-contact tower 220 is provided with a first washing liquid inlet 224, and the outlet end of the methylethane cooling channel 140 is communicated with the first washing liquid inlet 224. In this arrangement, the methane and ethane removed by the demethylethane tower 310 are cooled by the methylethane cooling channel 140, and then enter the re-contact tower 220 through the first washing liquid inlet 224 to serve as the washing liquid of the re-contact tower 220, which is beneficial for the re-contact tower 220 to better remove light components such as methane and ethane and improve the distillation effect.

[0063] Of course, in other embodiments, the second gas phase outlet 313 may also be connected to other devices, that is, the methane and ethane removed by the demethylation and ethane removal tower 310 are not used as the washing liquid of the re-contact tower 220.

[0064] In a further embodiment, the methyl ethane cooling channel 140 includes a first cooling channel 141 and a second cooling channel 142, the inlet end of the first cooling channel 141 is connected to the second gas phase outlet 313, and the outlet end of the second cooling channel 142 is connected to the first washing liquid inlet 224. The pyrolysis coal gas recovery equipment also includes a demethylated ethane separator 320, the inlet end of the demethylated ethane separator 320 is connected to the outlet end of the first cooling channel 141, the gas phase outlet end of the demethylated ethane separator 320 is connected to the inlet end of the second cooling channel 142, and the liquid phase outlet end of the demethylated ethane separator 320 is connected to the second inlet 311 of the demethylated ethane tower 310.

[0065] That is to say, the methane and ethane removed by the demethylation ethane tower 310 are cooled by the first cooling channel 141 and then further enter the demethylation ethane separator 320 for separation. The separated gas components are cooled by the second cooling channel 142 and then enter the re-contact tower 220 through the first washing liquid inlet 224 to serve as the washing liquid of the re-contact tower 220, while the separated liquid components return to the demethylation ethane tower 310.

[0066] Optionally, the methane and ethane removed by the demethylation ethane tower 310 enter the first cooling channel 141 and are cooled to -36°C, and then enter the demethylation ethane separator 320 for separation. The separated gas is deep-cooled to -140°C through the second cooling channel 142 and then enters the re-contact tower 220 through the first washing liquid inlet 224.

[0067] In this configuration, a demethylethane separator 320 is added on the basis of the removal by the demethylethane tower 310 to further extract methane and ethane light components, thereby further improving the recovery rate.

[0068] Optionally, the pyrolysis coal gas recovery device further includes a demethylated ethane reflux pump 330, the inlet end of the demethylated ethane reflux pump 330 is connected to the liquid phase outlet end of the demethylated ethane separator 320, and the outlet end of the demethylated ethane reflux pump 330 is connected to the first washing liquid inlet 224. In this way, the liquid phase separated by the demethylated ethane separator 320 is pumped into the demethylated ethane tower 310 under the pressure boosting effect of the demethylated ethane reflux pump 330, thereby improving the circulation speed and processing efficiency.

[0069] Of course, in other embodiments, only one methyl ethane cooling channel 140 is provided, and the pyrolysis gas recovery equipment is not provided with a demethyl ethane separator 320, that is, the methane and ethane components removed by the demethyl ethane tower 310 directly enter the re-contact tower 220 after passing through the methyl ethane cooling channel 140.

[0070] In an alternative embodiment, reference Figure 1-Figure 2 as well as Figure 7As shown, the pyrolysis coal gas recovery equipment also includes a light hydrocarbon cooler 450, the inlet end of the light hydrocarbon cooler 450 is connected to the third liquid phase outlet 412, and the outlet end of the light hydrocarbon cooler 450 is used for light hydrocarbon substances to flow out. Optionally, the light hydrocarbon cooler 450 cools the liquid phase removed by the liquefied gas tower 410 to 40°C. In this way, the liquid phase removed by the liquefied gas tower 410 is cooled by the light hydrocarbon cooler 450 to form stable light hydrocarbon substances and products.

[0071] Optionally, a liquefied gas reboiler 460 is provided at the bottom of the liquefied gas tower 410, and the material in the liquefied gas tower 410 is distilled under the action of the liquefied gas reboiler 460, and is further cooled by the light hydrocarbon cooler 450 to form stable light hydrocarbon material and products.

[0072] Of course, in other embodiments, the pyrolysis gas recovery device may not be equipped with the light hydrocarbon cooler 450, and the liquid phase removed from the liquefied gas tower 410 is directly prepared and cooled by equipment other than the pyrolysis gas recovery device.

[0073] In an optional embodiment, the outlet end of the coal gas cooling channel 110 is directly connected to the first inlet 221 of the re-contact tower 220 .

[0074] In another embodiment, reference Figure 1-Figure 2 as well as Figure 7 As shown, the pyrolysis coal gas recovery equipment further includes a low temperature separator 210, the inlet end of the low temperature separator 210 is connected to the outlet end of the coal gas cooling channel 110, the gas phase outlet end of the low temperature separator 210 is connected to the first inlet 221 of the heavy contact tower 220, and the liquid phase outlet end of the low temperature separator 210 is connected to the inlet end of the heavy hydrocarbon cooling channel 120. That is, after being cooled, the pyrolysis coal gas first passes through the low temperature separator 210 for rough separation, and then further enters the heavy contact tower 220 for fine separation, and the liquid phase of the low temperature separator 210 and the liquid phase of the heavy contact tower 220 both enter the heavy hydrocarbon cooling channel 120 of the cold box 100.

[0075] With such arrangement, after the pyrolysis coal gas is cooled and before entering the heavy contact tower 220, it first passes through the low-temperature separator 210 for rough separation, and then passes through the heavy contact tower 220 for distillation, which is beneficial to improving the distillation effect of the heavy contact tower 220 and increasing the recovery rate of light components such as methane, ethane, and propane.

[0076] In an optional embodiment, the number of the gas cooling channel 130 is one, the inlet end of the gas cooling channel 130 is connected to the first gas phase outlet 223 , and the outlet end of the gas cooling channel 130 is connected to the dehydrogenation inlet 511 .

[0077] In another embodiment, if Figure 3As shown, the gas cooling channel 130 includes a third cooling channel 131 and a fourth cooling channel 132, the inlet end of the third cooling channel 131 is connected to the first gas phase outlet 223, and the outlet end of the fourth cooling channel 132 is connected to the dehydrogenation inlet 511. The decarbonization device 600 is provided with a decarbonization reboiler 640, the inlet end of the decarbonization reboiler 640 is connected to the outlet end of the third cooling channel 131, and the outlet end of the decarbonization reboiler 640 is connected to the inlet end of the fourth cooling channel 132. That is, the light components such as methane and ethane removed by the heavy contact tower 220 (i.e., methane-rich gas) enter the decarbonization reboiler 640 after being cooled by the third cooling channel 131, so as to provide heat for the decarbonization reboiler 640, and the methane-rich gas after providing heat is cooled by the fourth cooling channel 132 and then flows into the dehydrogenation inlet 511, and the dehydrogenation process begins.

[0078] Optionally, the methane-rich gas is deep-cooled to -120°C through the third cooling channel 131, and the methane-rich gas after providing heat for the decarbonization reboiler 640 is deep-cooled to -160°C through the fourth cooling channel 132 and then dehydrogenated to obtain hydrogen-rich gas at -176°C.

[0079] Optionally, the decarbonization device 600 includes a decarbonization tower 610 , and the decarbonization reboiler 640 is disposed at the bottom of the decarbonization tower 610 .

[0080] With such arrangement, light components such as methane and ethane removed from the heavy contact tower 220 undergo two cooling processes in sequence to provide heat to the decarbonization reboiler 640 at the bottom of the decarbonization device 600. No additional heating is required for the decarbonization reboiler 640, which is conducive to full utilization and energy saving.

[0081] In an optional embodiment, Figure 4 As shown, the dehydrogenation device 500 includes a dehydrogenation tower 510, a dehydrogenation cooler 520 and a dehydrogenation separator 530. The dehydrogenation tower 510 is provided with a dehydrogenation inlet 511 and a first LNG outlet 512. The methane-rich gas cooled by the gas cooling channel 130 enters the dehydrogenation tower 510 from the dehydrogenation inlet 511 for dehydrogenation treatment, and the LNG after dehydrogenation flows out from the first LNG outlet 512 at the bottom of the dehydrogenation tower 510; a fourth gas phase outlet 513 is provided at the top of the dehydrogenation tower 510, the inlet end of the dehydrogenation cooler 520 is connected to the fourth gas phase outlet 513, the outlet end of the dehydrogenation cooler 520 is connected to the inlet end of the dehydrogenation separator 530, and the gas phase outlet end of the dehydrogenation separator 530 is a hydrogen outlet 531, that is, the gas at the top of the dehydrogenation tower 510 is cooled by the dehydrogenation cooler 520 and further separated by the dehydrogenation separator 530, and the separated gas is hydrogen.

[0082] With such arrangement, the dehydrogenation tower 510 dehydrogenates the methane-rich gas to obtain not only LNG, but also hydrogen in cooperation with the dehydrogenation cooler 520 and the dehydrogenation separator 530 .

[0083] In another embodiment, a second washing liquid inlet 514 is provided at the top of the dehydrogenation tower 510, and a liquid phase outlet end of the dehydrogenation separator 530 is connected to the second washing liquid inlet 514. In this configuration, the top gas of the dehydrogenation tower 510 is cooled by the dehydrogenation cooler 520 and then further separated by the dehydrogenation separator 530, and the separated liquid phase is used as the washing liquid of the dehydrogenation tower 510, which is beneficial for the dehydrogenation tower 510 to better remove hydrogen and obtain usable hydrogen, and is also beneficial for improving the purity of hydrogen.

[0084] In an optional embodiment, Figure 5 As shown, the decarbonization device 600 includes a decarbonization tower 610, a decarbonization cooler 620 and a decarbonization separator 630. The decarbonization tower 610 is provided with a decarbonization inlet 611 and a second LNG outlet 612. The LNG flowing out through the first LNG outlet 512 enters the decarbonization tower 610 through the decarbonization inlet 611 for decarbonization treatment; the top of the decarbonization tower 610 is provided with a fifth gas phase outlet 613, the inlet end of the decarbonization cooler 620 is connected to the fifth gas phase outlet 613, the outlet end of the decarbonization cooler 620 is connected to the inlet end of the decarbonization separator 630, and the gas phase outlet end of the decarbonization separator 630 is a carbon gas outlet 631. That is to say, the top gas of the decarbonization tower 610 is cooled by the decarbonization cooler 620 and further separated by the decarbonization separator 630. The separated gas is carbon gas, which is carbon monoxide gas.

[0085] With such arrangement, the decarbonization tower 610 performs decarbonization treatment, not only obtaining LNG that can be directly prepared, but also obtaining carbon gas in cooperation with the decarbonization cooler 620 and the decarbonization separator 630 .

[0086] In another embodiment, a third washing liquid inlet 614 is provided at the top of the decarbonization tower 610, and the liquid phase outlet end of the decarbonization separator 630 is connected to the third washing liquid inlet 614. In this configuration, the top gas of the decarbonization tower 610 is cooled by the decarbonization cooler 620 and then further separated by the decarbonization separator 630, and the separated liquid phase is used as the washing liquid of the decarbonization tower 610, which is conducive to better removal of carbon gas by the decarbonization tower 610 to obtain usable carbon gas.

[0087] In this embodiment, if Figure 1 , Figure 3 and Figure 7As shown, the pyrolysis coal gas recovery equipment also includes an LNG storage tank 700, a volatile gas blower 810, a volatile gas reheater 820, and a volatile gas cooler 830, wherein the LNG storage tank 700 is connected to the second LNG outlet 612, that is, the LNG storage tank 700 stores LNG products, and the volatile gas of the product during the storage process in the LNG storage tank 700 is reheated by the volatile gas reheater 820 and then enters the volatile gas blower 810. Under the pressurization effect of the volatile gas blower 810, the volatile gas is cooled by the volatile gas cooler 830 and then sent to the external fuel system to be used as fuel.

[0088] In an optional embodiment, the cold box 100 is further provided with a first LNG cooling channel 150, a second LNG cooling channel 160, a hydrogen cooling channel 170 and a carbon gas cooling channel 180, the inlet end of the first LNG cooling channel 150 is connected to the first LNG outlet 512, the outlet end of the first LNG cooling channel 150 is connected to the decarbonization inlet 611, and the second LNG cooling channel 160 is connected to the second LNG outlet 612, that is, the LNG after dehydrogenation by the dehydrogenation device 500 enters the first LNG cooling channel 150 for cooling and then enters the decarbonization device 600, and the LNG after decarbonization by the decarbonization device 600 enters the second LNG cooling channel 160 for cooling and then is prepared. Moreover, the hydrogen cooling channel 170 is connected to the hydrogen outlet 531, and the carbon gas cooling channel 180 is connected to the carbon gas outlet 631, so that the hydrogen removed by the dehydrogenation device 500 is cooled by the hydrogen cooling channel 170 and then is prepared, and similarly, the carbon removed by the decarbonization device 600 is cooled by the carbon gas cooling channel 180 and then is prepared.

[0089] Optionally, LNG at -160°C flows out from the first LNG outlet 512, which is reheated to -145°C through the first LNG cooling channel 150 and then enters the decarbonization device 600, and LNG at -131°C flows out from the second LNG outlet 612, which is cooled to -162°C through the second LNG cooling channel 160 and then enters the LNG storage tank 700; the dehydrogenation device 500 removes hydrogen at -176°C, which is reheated to 45°C through the hydrogen cooling channel 170, and the decarbonization device 600 removes carbon gas at -168°C, which is reheated to 35°C through the carbon gas cooling channel 180.

[0090] With such arrangement, the LNG obtained after dehydrogenation undergoes a reheating process in the cold box 100 so that the LNG reaches a suitable temperature for decarbonization; the LNG obtained after decarbonization undergoes a cooling process in the cold box 100 so that the LNG reaches a suitable temperature for preparation. Similarly, hydrogen and carbon gas are respectively reheated in the cold box 100 to obtain stable and usable gases.

[0091] In an alternative embodiment, reference Figure 7As shown, the cold box 100 includes a shallow cooling section, an intermediate cooling section and a supercooling section, the coal gas cooling channel 110 and the gas cooling channel 130 are both arranged in the intermediate cooling section, the heavy hydrocarbon cooling channel 120 is arranged in the shallow cooling section, the dehydrogenation device 500 and the decarbonization device 600 are respectively provided with a dehydrogenation cooling inlet 515 and a decarbonization cooling inlet 615, and the dehydrogenation cooling inlet 515 and the decarbonization cooling inlet 615 are respectively connected to the channel of the supercooling section.

[0092] Optionally, the temperature range of the shallow cooling section is between -35°C and room temperature, the temperature range of the intermediate cooling section is between -160°C and -15°C, and the temperature of the supercooling section is about -180°C. Further optionally, the shallow cooling section is provided with cooling capacity by the propane compressor unit 930, the intermediate cooling section is provided with cooling capacity by the mixed refrigerant compressor unit 920, and the supercooling section is provided with cooling capacity by the nitrogen compressor unit 910, wherein the propane compressor unit 930 uses propane as the refrigerant, and the propane is pressurized to 1.3MPaG by the compressor unit and then further cooled to 40°C to become a liquid phase; the mixed refrigerant compressor unit 920 uses methane, ethane, propane, nitrogen isopentane, etc. as the mixed refrigerant, and the mixed refrigerant is pressurized to 3 by the compressor unit in two stages. .3MPaG, and then cooled and separated in sequence before entering the cold box 100. The first-stage pre-cooling can reach -15℃, and after throttling and reducing pressure, it returns to the cold box 100. The second-stage pre-cooling is to -75℃, and after throttling and reducing pressure, it returns to the cold box 100. The third-stage deep cooling is to -160℃, and after throttling and reducing pressure, it returns to the cold box 100 for reheating, thereby obtaining cooling capacity in different temperature ranges; the nitrogen compressor unit 910 uses nitrogen as the refrigerant. The nitrogen is pressurized to 2.3MPaG by the compressor unit and then cooled to -182℃ by the cooler.

[0093] As described above, the coal gas cooling channel 110 precools the coal gas to -72°C, and the gas cooling channel 130 can deep cool the light components of the gas to -140°C, so the two are arranged in the intermediate cooling section; the heavy hydrocarbon cooling channel 120 reheats the heavy hydrocarbon material to 15°C, which is a relatively high temperature, so the heavy hydrocarbon cooling channel 120 is arranged in the shallow cooling section; the cooling temperature required by the dehydrogenation device 500 and the decarbonization device 600 is relatively low, which can reach -182°C, so the decarbonization cooling inlet 615 and the dehydrogenation cooling inlet 515 are arranged in the supercooling section to provide the required cooling for the dehydrogenation device 500 and the decarbonization device 600.

[0094] Optionally, the ethane cooling channel 140, the first LNG cooling channel 150 and the second LNG cooling channel 160 are arranged in the intermediate cooling section, and the hydrogen cooling channel 170 and the carbon gas cooling channel 180 are arranged in the shallow cooling section.

[0095] In this embodiment, the operating pressure of the heavy contact tower 220 is 2.25 MPaG, the temperature at the bottom of the tower is -79°C, and the temperature at the top of the tower is -87°C; the operating pressure of the demethyl ethane tower 310 is 2.2 MPaG, the temperature at the bottom of the tower is 86°C, and the temperature at the top of the tower is -7°C; the operating pressure of the dehydrogenation tower 510 is 2.15 MPaG, the temperature at the bottom of the tower is -160°C, and the temperature at the top of the tower is -176°C; the operating pressure of the decarbonization tower 610 is 0.6 MPaG, the temperature at the bottom of the tower is -131°C, and the temperature at the top of the tower is -168°C; the operating pressure of the liquefied gas tower 410 is 1.5 MPaG, the temperature at the bottom of the tower is 160°C, and the temperature at the top of the tower is 64°C.

[0096] In this way, the heavy contact tower 220, the demethylation and ethane tower 310, the liquefied gas tower 410, the dehydrogenation tower 510 and the decarbonization tower 610 respectively meet the above-mentioned operating pressure conditions and temperature conditions, which is beneficial to carry out each distillation process, improve the distillation effect, and further help to improve the recovery rate of the pyrolysis coal gas.

[0097] It should be noted that, in this embodiment, the ports can be connected through pipelines, and the sealing is ensured when the ports are connected to the pipelines to avoid leakage of various substances during the recovery process.

[0098] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A pyrolysis gas recovery device, characterized in that: include: A cold box (100), wherein the cold box (100) is provided with a coal gas cooling channel (110), a heavy hydrocarbon cooling channel (120) and a gas cooling channel (130), wherein the coal gas cooling channel (110) is used for circulating pyrolysis coal gas; A heavy contact tower (220), wherein the heavy contact tower (220) is provided with a first inlet (221), a first liquid phase outlet (222) and a first gas phase outlet (223), wherein the first inlet (221) is connected to the outlet end of the coal gas cooling channel (110), the first liquid phase outlet (222) is connected to the inlet end of the heavy hydrocarbon cooling channel (120), and the first gas phase outlet (223) is connected to the inlet end of the gas cooling channel (130); a demethylethane tower (310), wherein the demethylethane tower (310) is provided with a second inlet (311) and a second liquid phase outlet (312), and the outlet end of the heavy hydrocarbon cooling channel (120) of the cold box (100) is in communication with the second inlet (311); A liquefied gas tower (410), wherein the liquefied gas tower (410) is provided with a third inlet (411), a third liquid phase outlet (412) and a third gas phase outlet (413), wherein the third inlet (411) is connected to the second liquid phase outlet (312), the third gas phase outlet (413) is used for allowing LPG to flow out, and the third liquid phase outlet (412) is used for allowing light hydrocarbon substances to flow out; A dehydrogenation device (500), wherein the dehydrogenation device (500) is provided with a dehydrogenation inlet (511), a hydrogen outlet (531) and a first LNG outlet (512), wherein the dehydrogenation inlet (511) is communicated with the outlet end of the gas cooling channel (130), and the hydrogen outlet (531) is used for discharging hydrogen; A decarbonization device (600) is provided with a decarbonization inlet (611) and a second LNG outlet (612), wherein the decarbonization inlet (611) is connected to the first LNG outlet (512), and the second LNG outlet (612) is used for LNG to flow out.

2. The pyrolysis gas recovery equipment according to claim 1, characterized in that: The demethyl ethane tower (310) is provided with a second gas phase outlet (313), the cold box (100) is further provided with a methyl ethane cooling channel (140), the inlet end of the methyl ethane cooling channel (140) is communicated with the second gas phase outlet (313), the heavy contact tower (220) is provided with a first washing liquid inlet (224), and the outlet end of the methyl ethane cooling channel (140) is communicated with the first washing liquid inlet (224).

3. The pyrolysis gas recovery equipment according to claim 2, characterized in that: The methyl ethane cooling channel (140) comprises a first cooling channel (141) and a second cooling channel (142), wherein the inlet end of the first cooling channel (141) is in communication with the second gas phase outlet (313), and the outlet end of the second cooling channel (142) is in communication with the first washing liquid inlet (224). The pyrolysis coal gas recovery equipment also includes a demethylation ethane separator (320), the inlet end of the demethylation ethane separator (320) is connected to the outlet end of the first cooling channel (141), the gas phase outlet end of the demethylation ethane separator (320) is connected to the inlet end of the second cooling channel (142), and the liquid phase outlet end of the demethylation ethane separator (320) is connected to the second inlet (311) of the demethylation ethane tower (310).

4. The pyrolysis gas recovery equipment according to claim 1, characterized in that: The pyrolysis coal gas recovery equipment also includes a liquefied gas cooler (420) and a liquefied gas separator (430), the inlet end of the liquefied gas cooler (420) is connected to the third gas phase outlet (413), the outlet end of the liquefied gas cooler (420) is connected to the inlet end of the liquefied gas separator (430), and the liquid phase outlet end of the liquefied gas separator (430) is used for the LPG to flow out.

5. The pyrolysis gas recovery equipment according to claim 1, characterized in that: The pyrolysis coal gas recovery equipment also includes a light hydrocarbon cooler (450), the inlet end of the light hydrocarbon cooler (450) is connected to the third liquid phase outlet (412), and the outlet end of the light hydrocarbon cooler (450) is used for the light hydrocarbon material to flow out.

6. The pyrolysis gas recovery equipment according to claim 1, characterized in that: The pyrolysis coal gas recovery equipment also includes a low-temperature separator (210), the inlet end of the low-temperature separator (210) is connected to the outlet end of the coal gas cooling channel (110), the gas phase outlet end of the low-temperature separator (210) is connected to the first inlet (221) of the heavy contact tower (220), and the liquid phase outlet end of the low-temperature separator (210) is connected to the inlet end of the heavy hydrocarbon cooling channel (120).

7. The pyrolysis gas recovery equipment according to claim 1, characterized in that: The gas cooling channel (130) comprises a third cooling channel (131) and a fourth cooling channel (132), wherein the inlet end of the third cooling channel (131) is connected to the first gas phase outlet (223), and the outlet end of the fourth cooling channel (132) is connected to the dehydrogenation inlet (511). The decarbonization device (600) is provided with a decarbonization reboiler (640), the inlet end of the decarbonization reboiler (640) is connected to the outlet end of the third cooling channel (131), and the outlet end of the decarbonization reboiler (640) is connected to the inlet end of the fourth cooling channel (132).

8. The pyrolysis gas recovery equipment according to claim 1, characterized in that: The dehydrogenation device (500) comprises a dehydrogenation tower (510), a dehydrogenation cooler (520) and a dehydrogenation separator (530), wherein the dehydrogenation tower (510) is provided with the dehydrogenation inlet (511) and the first LNG outlet (512), the top of the dehydrogenation tower (510) is provided with a fourth gas phase outlet (513) and a second washing liquid inlet (514), the inlet end of the dehydrogenation cooler (520) is communicated with the fourth gas phase outlet (513), the outlet end of the dehydrogenation cooler (520) is communicated with the inlet end of the dehydrogenation separator (530), the liquid phase outlet end of the dehydrogenation separator (530) is communicated with the second washing liquid inlet (514), and the gas phase outlet end of the dehydrogenation separator (530) is the hydrogen outlet (531); And / or, the decarbonization device (600) includes a decarbonization tower (610), a decarbonization cooler (620) and a decarbonization separator (630), the decarbonization tower (610) is provided with the decarbonization inlet (611) and the second LNG outlet (612), the top of the decarbonization tower (610) is provided with a fifth gas phase outlet (613) and a third washing liquid inlet (614), the inlet end of the decarbonization cooler (620) is connected to the fifth gas phase outlet (613), the outlet end of the decarbonization cooler (620) is connected to the inlet end of the decarbonization separator (630), the liquid phase outlet end of the decarbonization separator (630) is connected to the third washing liquid inlet (614), and the gas phase outlet end of the decarbonization separator (630) is a carbon gas outlet (631).

9. The pyrolysis gas recovery equipment according to claim 8, characterized in that: The cold box (100) is also provided with a first LNG cooling channel (150), a second LNG cooling channel (160), a hydrogen cooling channel (170) and a carbon gas cooling channel (180); the inlet end of the first LNG cooling channel (150) is connected to the first LNG outlet (512); the outlet end of the first LNG cooling channel (150) is connected to the decarbonization inlet (611); the second LNG cooling channel (160) is connected to the second LNG outlet (612); the hydrogen cooling channel (170) is connected to the hydrogen outlet (531); and the carbon gas cooling channel (180) is connected to the carbon gas outlet (631).

10. The pyrolysis gas recovery equipment according to claim 1, characterized in that: The cold box (100) comprises a shallow cooling section, an intermediate cooling section and a supercooling section. The coal gas cooling channel (110) and the gas cooling channel (130) are both arranged in the intermediate cooling section. The heavy hydrocarbon cooling channel (120) is arranged in the shallow cooling section. The dehydrogenation device (500) and the decarbonization device (600) are respectively provided with a dehydrogenation cooling inlet (515) and a decarbonization cooling inlet (615). The dehydrogenation cooling inlet (515) and the decarbonization cooling inlet (615) are respectively connected to the channel of the supercooling section.

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