Pressurizing washing system for low-temperature pyrolysis coal gas

Abstract

The utility model provides a supercharging washing system for low-temperature pyrolysis gas, which relates to the technical field of gas purification and comprises a plurality of stages of gas superchargers which are sequentially connected according to the passing sequence of the low-temperature pyrolysis gas, the multiple stages of gas superchargers are used for performing stage-by-stage pressurization on the low-temperature pyrolysis gas, so that non-condensable gas is condensed; except the last-stage gas supercharger, the gas outlet of each stage of gas supercharger is independently provided with an outlet cooler and a gas-liquid separator connected with the outlet cooler; and the gas-liquid separator is connected with a gas inlet of the coal gas supercharger through the water washing tower and / or the oil washing tower and is used for washing the separated gas and then feeding the gas into the next-stage coal gas supercharger for supercharging. According to the utility model, the consumption of new desalted water and new washing oil can be saved, the energy is saved, the emission is reduced, meanwhile, dust, ammonia, ammonium salt, inorganic sulfur, organic sulfur and hydrocarbons with more than 5 carbon atoms contained in coal gas can be effectively removed and separated, and better conditions are created for preparing LNG and LPG (Liquefied Petroleum Gas).

Description

Technical Field

[0001] This utility model relates to the technical field of coal gas purification, and in particular to a pressurized scrubbing system for low-temperature pyrolysis coal gas. Background Technology

[0002] The low-temperature pyrolysis process of coal mainly utilizes crushed coal (particle size less than 30mm) for indirect heating and pyrolysis in a rotary kiln. The calorific value of the crude coal gas produced by pyrolysis is higher than that of coal gas produced by other pyrolysis methods. Through absorption analysis, it was found that the methane content in the low-temperature pyrolysis coal gas is greater than 30% by volume, the content of C2-4 hydrocarbons is about 10% by volume, and the light oil content of C5-10 is as high as 30-60 g / Nm³. 3 If this type of gas is used for combustion, it will not only fail to burn completely, which is detrimental to energy conservation and emission reduction, but it will also fail to realize its full potential. Therefore, only by separating the hydrocarbons and other substances from the gas to realize their respective values, while removing substances harmful to the separation equipment, can it have greater practical value.

[0003] In view of the above, this utility model is hereby proposed. Utility Model Content

[0004] The purpose of this invention is to provide a pressurized washing system for low-temperature pyrolysis coal gas, which can save the amount of new demineralized water and new washing oil, save energy and reduce emissions, and effectively remove and separate dust, ammonia, ammonium salts, inorganic sulfur, organic sulfur and hydrocarbons with more than 5 carbons contained in the coal gas, creating better conditions for the production of LNG and LPG.

[0005] The low-temperature pyrolysis gas booster and scrubbing system provided by this utility model includes several stages of gas booster connected in sequence according to the flow order of the low-temperature pyrolysis gas.

[0006] The aforementioned multi-stage gas booster is used to progressively pressurize low-temperature pyrolysis gas, causing non-condensable gases to condense.

[0007] Except for the final stage gas booster, each stage gas booster is equipped with an outlet cooler and a gas-liquid separator connected to the outlet cooler.

[0008] The gas-liquid separator is connected to the inlet of the gas booster through a water washing tower and / or an oil washing tower, and is used to wash the separated gas before it enters the next stage gas booster for pressurization.

[0009] Furthermore, the gas booster has 3 to 5 stages.

[0010] Furthermore, the gas booster has 5 stages.

[0011] Furthermore, the primary gas booster is equipped with a dust separator at the air inlet to remove dust and prevent it from entering the gas booster.

[0012] Furthermore, according to the sequence of the low-temperature pyrolysis gas, the outlet pipelines of the first-stage gas booster and the second-stage gas booster are each equipped with an independent water washing tower, the outlet pipeline of the third-stage gas booster is equipped with both a water washing tower and an oil washing tower, and the outlet pipeline of the fourth-stage gas booster is equipped with an oil washing tower.

[0013] Furthermore, the pressure at the outlet of the primary gas booster is lower than the pressure at the outlet of the secondary gas booster.

[0014] The outlet pressure of the secondary gas booster is lower than that of the tertiary gas booster.

[0015] The outlet pressure of the three-stage gas booster is lower than that of the four-stage gas booster.

[0016] The outlet pressure of a four-stage gas booster is lower than that of a five-stage gas booster.

[0017] Furthermore, a water pump is installed at the water inlet of the washing tower on the gas outlet pipeline of the three-stage gas booster.

[0018] Furthermore, the water washing towers are interconnected.

[0019] Furthermore, an oil pump is installed at the oil inlet of the oil washing tower on the gas outlet pipeline of the fourth-stage gas booster.

[0020] Furthermore, the oil washing towers are interconnected.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The low-temperature pyrolysis gas pressurization and washing system provided by this utility model is a pressurization and washing system for dust removal, dehydration, oil removal and impurity removal. Through pressurization and washing, the dust, ammonia, ammonium salts, inorganic sulfur, organic sulfur and hydrocarbons with carbon 5 or higher contained in the crude gas are effectively separated or removed, thereby avoiding interference or wear of the gas booster by dust and tar. Since the ammonia and ammonium salts contained in the gas are removed, and some inorganic sulfur and organic sulfur are removed, as well as hydrocarbons with carbon 5 or higher are separated, the subsequent production of LNG and LPG will be purer. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of a low-temperature pyrolysis gas pressurization and washing system provided in one embodiment of the present invention.

[0025] Icons: 1-First-stage gas booster; 2-Second-stage gas booster; 3-Third-stage gas booster; 4-Fourth-stage gas booster; 5-Fifth-stage gas booster; 6-Drive motor; 11-First-stage outlet cooler; 21-Second-stage outlet cooler; 31-Third-stage outlet cooler; 41-Fourth-stage outlet cooler; 12-First-stage outlet gas-liquid separator; 22-Second-stage outlet gas-liquid separator; 32-Third-stage outlet gas-liquid separator; 42-Fourth-stage outlet gas-liquid separator; 13-First-stage inlet dust separator; 14-First-stage water scrubber; 24-Second-stage water scrubber; 34-First-stage oil scrubber; 341-Third-stage water scrubber; 44-Second-stage oil scrubber; 15-First water pump; 25-Second water pump; 35-Third water pump; 45-Oil pump. Detailed Implementation

[0026] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0027] This utility model provides a pressurization and washing system for low-temperature pyrolysis gas, which includes several stages of gas booster connected in sequence according to the flow order of the low-temperature pyrolysis gas.

[0028] A multi-stage gas booster is used to progressively pressurize low-temperature pyrolysis gas, causing non-condensable gases to condense.

[0029] In addition to the final stage gas booster, each stage gas booster is equipped with an outlet cooler and a gas-liquid separator connected to the outlet cooler.

[0030] Furthermore, the gas-liquid separator is connected to the inlet of the gas booster through a water washing tower and / or an oil washing tower, which is used to wash the separated gas before it enters the next stage gas booster for pressurization.

[0031] This invention relates to a pressurization and washing system for producing LNG and LPG from low-temperature pyrolysis coal gas. The coal gas from the crude coal gas holder is pressurized by coal gas boosters at each stage. Each stage of the coal gas booster is equipped with an inlet and an outlet. Except for the outlet of the last stage coal gas booster, which does not have a cooler, the outlet of each other stage coal gas booster is equipped with an outlet cooler. After the outlet cooler, a gas-liquid separator is installed. The gas-liquid separator is connected to the inlet of the next stage coal gas booster through a water washing tower and / or an oil washing tower. In this way, the gas separated from the gas-liquid separator at the outlet of the previous stage coal gas booster is washed by the water washing tower and / or oil washing tower before entering the inlet of the next stage coal gas booster.

[0032] In this invention, the coal gas is separated by a gas-liquid separator to remove moisture, particulate matter, and light coal tar. It is then washed by a water washing tower and / or an oil washing tower to further remove moisture, particulate matter, and light coal tar. At the same time, ammonia, ammonium salts, some organic sulfur, and inorganic sulfur contained in the coal gas are also removed. In this way, not only can the service life of the coal gas booster be effectively extended, but the coal gas can also be effectively purified before LNG and LPG production.

[0033] The gas booster in this invention can have 3 to 5 stages, and 5 stages are preferred.

[0034] Low-temperature pyrolysis gas is progressively pressurized by a 3- to 5-stage gas booster. At normal temperature and pressure, the non-condensable gas will become condensable. After being washed by a water washing tower, dust, ammonia, ammonium salts, and inorganic sulfur are washed away, as well as some organic sulfur and some light oil. After being washed by an oil washing tower, light hydrocarbon oils with carbon 5 or higher and some organic sulfur are washed away. Finally, after being separated by a gas-liquid separator, impurities are separated out, creating better conditions for the production of LNG and LPG.

[0035] In a preferred embodiment, the pressurization and washing system includes a first-stage gas booster, a second-stage gas booster, a third-stage gas booster, a fourth-stage gas booster, and a fifth-stage gas booster connected in sequence according to the flow order of the low-temperature pyrolysis gas. The pressure of the gas booster increases step by step from the first stage to the fifth stage, and a drive motor is also provided on the gas booster.

[0036] In a preferred embodiment, the air inlet of the primary gas booster (i.e., the first-stage gas booster) may also be equipped with a dust separator to remove most of the dust, thereby preventing dust from entering the booster and causing wear to the booster equipment.

[0037] In a preferred embodiment, according to the sequence of the low-temperature pyrolysis gas, the outlet pipelines of the first-stage gas booster and the second-stage gas booster are each equipped with an independent water washing tower, the outlet pipeline of the third-stage gas booster is equipped with both a water washing tower and an oil washing tower, and the outlet pipeline of the fourth-stage gas booster is equipped with an oil washing tower.

[0038] In this utility model, a water washing tower is installed on the outlet pipeline of the first-stage gas booster, which is called the first-stage water washing tower; a water washing tower is installed on the outlet pipeline of the second-stage gas booster, which is called the second-stage water washing tower; a water washing tower and an oil washing tower are installed on the outlet pipeline of the third-stage gas booster, which is called the third-stage water washing tower and the first-stage oil washing tower, and a third-stage water washing tower is installed after the first-stage oil washing tower on the third-stage outlet pipeline; and an oil washing tower is installed on the outlet pipeline of the fourth-stage gas booster, which is called the second-stage oil washing tower.

[0039] In this invention, the water washing towers are interconnected, and the oil washing towers are interconnected.

[0040] Washing with water at relatively low pressure is highly efficient at dissolving inorganic substances such as ammonium salts and ammonia, while washing with oil at relatively high pressure is highly efficient at dissolving organic substances such as benzene, naphthalene, and organic sulfur compounds.

[0041] It should be noted that after the first two stages of water washing towers, most of the water-soluble impurities have been removed. Next, benzene, naphthalene, and organic sulfur compounds need to be washed to avoid excessive organic content in the gas. A third-stage water washing tower is set after the first-stage oil washing tower on the third-stage gas outlet pipeline. After the first-stage oil washing tower, there may still be water-soluble impurities in the gas, so it will be washed again by the third-stage water washing tower.

[0042] In a preferred embodiment, the pressure at the outlet of the primary gas booster is lower than the pressure at the outlet of the secondary gas booster.

[0043] The outlet pressure of the secondary gas booster is lower than that of the tertiary gas booster.

[0044] The outlet pressure of the three-stage gas booster is lower than that of the four-stage gas booster.

[0045] The outlet pressure of a four-stage gas booster is lower than that of a five-stage gas booster.

[0046] It should be noted that, according to the sequence of the low-temperature pyrolysis gas flow, the inlet pressure of the first-stage gas booster can be a slightly positive pressure of 3 kPa to 10 kPa, the outlet pressure of the first-stage gas booster can be 0.15 MPa to 0.2 MPa, the outlet pressure of the second-stage gas booster can be 0.35 MPa to 0.42 MPa, the outlet pressure of the third-stage gas booster can be 0.65 MPa to 0.85 MPa, the outlet pressure of the fourth-stage gas booster can be 1.88 MPa to 1.93 MPa, and the outlet pressure of the fifth-stage gas booster can be 3.2 MPa to 4.5 MPa.

[0047] In a preferred embodiment, a first water pump is provided in the primary water washing tower, a second water pump is provided between the bottom of the secondary water washing tower and the upper part of the primary water washing tower, a third water pump is provided at the inlet of the tertiary water washing tower, and an oil pump is provided at the inlet of the secondary oil washing tower.

[0048] A washing method using the pressurized washing system described in any one of the above claims includes the following steps:

[0049] The low-temperature pyrolysis gas is passed through a series of gas booster presses for step-by-step pressurization. The gas first passes through a gas-liquid separator to separate moisture, particulate matter and light coal tar. Then it passes through a water washing tower and an oil washing tower to further remove moisture, particulate matter and light coal tar. At the same time, ammonia, ammonium salts, organic sulfur and inorganic sulfur contained in the gas are removed to obtain purified gas.

[0050] Specifically, the third water pump uses demineralized water to raise the pressure to a level greater than the outlet pressure of the third stage, and sprays fresh demineralized water into the upper part of the third-stage water washing tower to wash the gas flowing counter-currently in the third-stage water washing tower. The lower part of the third-stage water washing tower is connected to the upper part of the second-stage water washing tower through a pipeline. By relying on the pressure difference, the water washed by the third-stage water washing tower is forced into the upper part of the second-stage water washing tower to wash the gas flowing counter-currently in the second-stage water washing tower.

[0051] The washing water at the bottom of the secondary water washing tower is injected into the upper part of the primary water washing tower through the second water pump to wash the gas flowing in the countercurrent of the primary water washing tower. The first water pump installed in the primary water washing tower washes the gas flowing in the countercurrent of the primary water washing tower, and the excess demineralized water is discharged for treatment.

[0052] The oil pump uses fresh wash oil or wash oil that has been re-distilled to raise the pressure to above the fourth-stage outlet pressure. The fresh wash oil is then injected into the upper part of the second-stage oil washing tower to wash the countercurrent gas in the second-stage oil washing tower. The lower part of the second-stage oil washing tower is connected to the upper part of the first-stage oil washing tower through a pipeline. By relying on the pressure difference, the wash oil washed in the second-stage oil washing tower is forced into the first-stage oil washing tower to wash the countercurrent gas in the first-stage oil washing tower. The washed wash oil is then discharged from the lower part of the first-stage oil washing tower and enters the fractionation facility.

[0053] Example 1

[0054] A pressurized scrubbing system for low-temperature pyrolysis gas, structural schematic diagram shown below. Figure 1 According to the sequence of the low-temperature pyrolysis gas, it includes a first-stage gas booster 1, a second-stage gas booster 2, a third-stage gas booster 3, a fourth-stage gas booster 4, and a fifth-stage gas booster 5 connected in sequence.

[0055] Meanwhile, the gas booster is also equipped with a drive motor 6;

[0056] The gas exiting the crude gas holder is pressurized by gas boosters at each stage. Each gas booster has an inlet and an outlet. The inlet pressure of the first-stage gas booster 1 is 3 kPa to 10 kPa, and the outlet pressure is 0.15 MPa to 0.2 MPa. The outlet pressure of the second-stage gas booster 2 is 0.35 MPa to 0.42 MPa. The outlet pressure of the third-stage gas booster 3 is 0.65 MPa to 0.85 MPa. The outlet pressure of the fourth-stage gas booster 4 is 1.88 MPa to 1.93 MPa. The outlet pressure of the fifth-stage gas booster 5 is 3.2 MPa to 4.5 MPa.

[0057] In addition, except for the outlet of the fifth-stage gas booster 5 which is not equipped with a cooler, the outlets of the first-stage gas booster 1, the second-stage gas booster 2, the third-stage gas booster 3 and the fourth-stage gas booster 4 are all equipped with outlet coolers, namely the first-stage outlet cooler 11, the second-stage outlet cooler 21, the third-stage outlet cooler 31 and the fourth-stage outlet cooler 41, respectively. Furthermore, gas-liquid separators are installed after each stage of outlet cooler, namely the first-stage outlet gas-liquid separator 12, the second-stage outlet gas-liquid separator 22, the third-stage outlet gas-liquid separator 32 and the fourth-stage outlet gas-liquid separator 42, respectively.

[0058] Each gas-liquid separator is connected to the inlet of the next stage gas booster through a water washing tower and / or an oil washing tower. The gas separated from the gas-liquid separator at the outlet of the previous stage gas booster is washed by the water washing tower and / or the oil washing tower before entering the inlet of the next stage gas booster.

[0059] After the first-stage outlet gas-liquid separator 12, the second-stage outlet gas-liquid separator 22, the third-stage outlet gas-liquid separator 32 and the fourth-stage outlet gas-liquid separator 42, a first-stage water washing tower 14, a second-stage water washing tower 24, a first-stage oil washing tower 34 and a second-stage oil washing tower 44 are set up in sequence. A third-stage water washing tower 341 is set up between the first-stage oil washing tower 34 and the air inlet of the fourth-stage gas booster 4.

[0060] The water washing towers are interconnected, and the oil washing towers are interconnected.

[0061] Meanwhile, the first-stage water washing tower 14 is equipped with a first water pump 15, the second-stage water washing tower 24 is equipped with a second water pump 25 between the bottom and the top of the first-stage water washing tower 14, the third-stage water washing tower 341 is equipped with a third water pump 35 at the water inlet, and the second-stage oil washing tower 44 is equipped with an oil pump 45 at the oil inlet.

[0062] It should be noted that the particulate matter content in the gas before purification was 6000 mg / Nm³. 3 Ammonia content 1500 mg / Nm 3 The organic sulfur content is 50 ppm, and the light oil content is 53 g / Nm³. 3The particulate matter content in the purified gas is 5 mg / Nm³. 3 The ammonia content is 8 mg / Nm³. 3 The organic sulfur content is 35 ppm, and the light oil content is 3 g / Nm³. 3 .

[0063] Example 2

[0064] This embodiment provides a pressurization and scrubbing system for low-temperature pyrolysis gas. The only difference from Embodiment 1 is that a primary inlet dust separator 13 is also installed at the inlet of the primary gas booster 1 to remove most of the dust, preventing dust from entering the booster and causing wear to the equipment. The particulate matter content in the gas before entering the primary inlet dust separator 13 is 6100 mg / Nm³. 3 The particulate matter content in the gas after passing through the primary inlet dust separator 13 is 4200 mg / Nm³. 3 It has a significant effect on reducing the wear of the primary gas booster;

[0065] All other settings are the same as in Example 1.

[0066] Example 3

[0067] This embodiment provides a pressurization and scrubbing system for low-temperature pyrolysis gas. The only difference from Embodiment 1 is that the inlet pressure of the first-stage gas booster 1 is 10 kPa, the outlet pressure of the first-stage gas booster 1 is 0.2 MPa, the outlet pressure of the second-stage gas booster 2 is 0.42 MPa, the outlet pressure of the third-stage gas booster 3 is 0.85 MPa, the outlet pressure of the fourth-stage gas booster 4 is 1.88 MPa to 1.93 MPa, and the outlet pressure of the fifth-stage gas booster 5 is 34.5 MPa.

[0068] All other settings are the same as in Example 1;

[0069] Compared to Example 1, a larger final pressure outlet is obtained, which is more beneficial for subsequent processes. Furthermore, the purification is further improved, with the particulate matter content in the purified gas reaching 4 mg / Nm³. 3 The ammonia content is 6 mg / Nm³. 3 The organic sulfur content is 32 ppm, and the light oil content is 2 g / Nm³. 3 .

[0070] Example 4

[0071] This embodiment provides a pressurization and scrubbing system for low-temperature pyrolysis gas. The only difference from Embodiment 1 is that the inlet pressure of the first-stage gas booster 1 is 6 kPa, the outlet pressure of the first-stage gas booster 1 is 0.18 MPa, the outlet pressure of the second-stage gas booster 2 is 0.39 MPa, the outlet pressure of the third-stage gas booster 3 is 0.71 MPa, the outlet pressure of the fourth-stage gas booster 4 is 1.90 MPa, and the outlet pressure of the fifth-stage gas booster 5 is 3.8 MPa.

[0072] All other settings are the same as in Examples 1 and 3;

[0073] Compared with Examples 1 and 3, Example 4 is between Example 1 and Example 3.

[0074] Comparative Example 1

[0075] This comparative example provides a pressurized washing system for low-temperature pyrolysis gas, which differs from Example 1 only in that it does not include a primary water washing tower 14 and a secondary water washing tower 24.

[0076] All other settings are the same as in Example 1;

[0077] Compared to Example 1, the drawback of this comparative example is that the particulate matter content at the inlet of the secondary gas booster 2 in Example 1 is 2000 mg / Nm³. 3 The particulate matter content at the inlet of the secondary gas booster 2 in Comparative Example 1 was as high as 5000 mg / Nm³. 3 The particulate matter content at the inlet of the three-stage gas booster 3 in Example 1 was 500 mg / Nm³. 3 The particulate matter content at the inlet of the three-stage gas booster in Comparative Example 1 was as high as 4500 mg / Nm³. 3 Compared to Example 1, the three-stage gas booster compressor 3 experiences a rapid increase in pressure drop and a short operating cycle. ； Furthermore, the particulate matter content in the purified gas is 25 mg / Nm³. 3 The ammonia content is 36 mg / Nm³. 3 The portion dissolved in water is not sufficiently removed.

[0078] Comparative Example 2

[0079] This comparative example provides a pressurized washing system for low-temperature pyrolysis gas, which differs from Example 1 only in that it does not include a primary oil washing tower 34 and a secondary oil washing tower 44.

[0080] All other settings are the same as in Example 1;

[0081] Compared to Example 1, the drawback of this comparative example is that the light oil content at the inlet of the four-stage gas booster compressor 4 in Example 1 is 7 g / Nm³. 3 The light oil content at the inlet of the four-stage gas booster compressor 4 in Comparative Example 2 was 35 g / Nm³.3 The light oil content at the inlet of the five-stage gas booster compressor 5 in Example 1 is 3g / Nm³. 3 The light oil content at the inlet of the five-stage gas booster compressor 5 in Comparative Example 2 was 21 g / Nm³. 3 A large amount of light oil enters the downstream process along with the gas, increasing the processing difficulty of the downstream process and even causing the downstream process to be unable to operate normally.

[0082] In summary, this utility model's pressurized washing system for dust removal, dehydration, oil removal, and impurity removal effectively separates or removes dust, ammonia, ammonium salts, inorganic sulfur, organic sulfur, and hydrocarbons with carbon 5 or higher from the crude coal gas through pressurized washing. This avoids interference or wear on the gas booster due to dust and tar. Because ammonia and ammonium salts are removed from the coal gas, along with some inorganic and organic sulfur and hydrocarbons with carbon 5 or higher, the subsequent production of LNG and LPG will be purer.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A pressurized scrubbing system for low temperature pyrolysis coal gas, characterized by, The low-temperature pyrolysis gas passes through several coal gas boosters in sequence; The several coal gas boosters are used to boost the low-temperature pyrolysis gas step by step, so that the non-condensed gas is condensed; Except for the last coal gas booster, each coal gas booster is independently provided with an outlet cooler and a gas-liquid separator connected with the outlet cooler; The gas-liquid separator is connected with the inlet of the coal gas booster through a water washing tower and / or an oil washing tower, and is used to make the separated gas pass through washing and then enter the next coal gas booster for boosting.

2. The pressurized washing system of claim 1, wherein, The number of the coal gas boosters is 3-5.

3. The pressurized washing system of claim 2, wherein, The number of the coal gas boosters is 5.

4. The pressurized washing system of claim 1, wherein, The inlet of the primary coal gas booster is provided with a dust separator, which is used to remove dust to avoid the dust entering the coal gas booster.

5. The pressurized washing system of claim 3, wherein, According to the passing sequence of the low-temperature pyrolysis gas, the outlet pipeline of the first coal gas booster and the second coal gas booster is independently provided with a water washing tower, the outlet pipeline of the third coal gas booster is provided with a water washing tower and an oil washing tower, and the outlet pipeline of the fourth coal gas booster is provided with an oil washing tower.

6. The pressurized washing system of claim 5, wherein, The pressure of the outlet of the first coal gas booster is less than that of the second coal gas booster; The pressure of the outlet of the second coal gas booster is less than that of the third coal gas booster; The pressure of the outlet of the third coal gas booster is less than that of the fourth coal gas booster; The pressure of the outlet of the fourth coal gas booster is less than that of the fifth coal gas booster.

7. The pressurized washing system of claim 5, wherein, The water inlet of the water washing tower on the outlet pipeline of the third coal gas booster is provided with a water pump.

8. The pressurized washing system of claim 7, wherein, The water washing towers are connected with each other.

9. The pressurized washing system of claim 5, wherein, The oil inlet of the oil washing tower on the outlet pipeline of the fourth coal gas booster is provided with an oil pump.

10. The pressurized washing system of claim 9, wherein, The oil washing towers are connected with each other.

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