阅读说明：本技术 水煤气变换系统及其预热方法 (Water gas shift system and preheating method thereof ) 是由 季旭华 武兴彬 江志杰 白天祥 李文明 孙长军 王晓旭 夏美丽 于 2021-01-15 设计创作，主要内容包括：本发明涉及煤化工领域,具体地涉及一种水煤气变换系统及其预热方法。一种水煤气变换系统,包括配气管线,配气管线上串接有预变炉组件,预变炉组件包括预变炉,预变炉包括炉壳和设置在炉壳内的用于水解羰基硫的第一催化剂,炉壳的两端分别设置有进气口和出气口,以使得由进气口进入的原料气穿过第一催化剂后由出气口排出。本发明的水煤气变换系统,预变炉的炉壳内含有用于水解羰基硫的第一催化剂,避免羰基硫随着水煤气进入后续工艺流程,降低后续低温甲醇洗系统对于羰基硫的吸收及再生负荷,进而减少净化气总硫的含量,同时避免低温甲醇洗再生酸性气中高含量的羰基硫进入硫回收系统,降低尾气加氢反应器的负荷,提高硫回收装置的稳定性。(The invention relates to the field of coal chemical industry, in particular to a water gas shift system and a preheating method thereof. The utility model provides a water gas shift system, includes the distribution pipeline, has concatenated the preceding stove subassembly that becomes on the distribution pipeline, and the preceding stove subassembly that becomes includes the stove that becomes in advance, and the preceding stove that becomes includes the stove outer covering and sets up the first catalyst that is used for hydrolysising carbonyl sulphur in the stove outer covering, and the both ends of stove outer covering are provided with air inlet and gas outlet respectively to make the feed gas that gets into by the air inlet pass behind the first catalyst by the gas outlet discharge. According to the water gas shift system, the furnace shell of the pre-shift furnace contains the first catalyst for hydrolyzing carbonyl sulfide, so that the carbonyl sulfide is prevented from entering a subsequent process flow along with water gas, the absorption and regeneration load of a subsequent low-temperature methanol washing system on the carbonyl sulfide is reduced, the total sulfur content of purified gas is further reduced, high-content carbonyl sulfide in low-temperature methanol washing regenerated acid gas is prevented from entering a sulfur recovery system, the load of a tail gas hydrogenation reactor is reduced, and the stability of a sulfur recovery device is improved.)

1. The water gas shift system is characterized by comprising a gas distribution pipeline (60), wherein a pre-changing furnace assembly is connected in series on the gas distribution pipeline (60), the pre-changing furnace assembly comprises a pre-changing furnace (1), the pre-changing furnace (1) comprises a furnace shell (2) and a first catalyst which is arranged in the furnace shell (2) and used for hydrolyzing carbonyl sulfide, and two ends of the furnace shell (2) are respectively provided with a gas inlet (3) and a gas outlet (4), so that a feed gas entering from the gas inlet (3) passes through the first catalyst and then is discharged from the gas outlet (4).

2. The water gas shift system according to claim 1, characterized in that the first catalyst comprises a hybrid catalyst (5) and a shift catalyst (6) for hydrolyzing a cos shift feed gas, which are arranged in sequence axially inside the furnace shell (2), the hybrid catalyst (5) comprising a cos hydrolysis catalyst and an oxygen removal catalyst.

3. The water gas shift system according to claim 2, characterized in that the pre-shift furnace (1) comprises ceramic balls (7) axially sandwiching the hybrid catalyst (5), the shift catalyst (6) in the furnace shell (2).

4. A water gas shift system according to claim 3, characterized in that the end of the porcelain ball (7) remote from the first catalyst is provided with a wire mesh (8) for fixing the porcelain ball (7).

5. The water gas shift system according to claim 1, characterized in that the pre-converter assembly comprises a first shell-and-tube heat exchanger (10) and the pre-converter (1), a first shell-and-tube outlet (11) of the first shell-and-tube heat exchanger (10) is communicated with the gas inlet (3), a first shell-and-tube inlet (12) of the first shell-and-tube heat exchanger (10) is communicated with the gas outlet (4), and the pre-converter assembly is arranged to be connected in series on the gas distribution line (60) through a first shell-and-tube inlet (14) and a first shell-and-tube outlet (13).

6. The water gas shift system according to claim 5, wherein the pre-converter assembly comprises a heat exchanger bypass pipeline (21) and a pre-converter bypass pipeline (20), two ends of the heat exchanger bypass pipeline (21) are respectively communicated with the first tube pass feeding hole (14) and the first tube pass discharging hole (11), two ends of the pre-converter bypass pipeline (20) are respectively communicated with the air inlet (3) and the air outlet (4), a heat exchanger bypass pipeline valve (23) is arranged on the heat exchanger bypass pipeline (21), a pre-converter bypass pipeline valve (22) is arranged on the pre-converter bypass pipeline (20), and a first tube pass discharging hole valve (15) is arranged on the first tube pass discharging hole (11).

7. The water gas shift system according to any one of claims 5-6, comprising a feed gas processing unit, a feed gas shift unit, a waste heat processing assembly and an ammonia wash column (77) in sequential communication, the feed gas shift unit comprising a shift line (80) and the gas distribution line (60) in parallel.

8. The water gas shift system according to claim 7, characterized in that the gas distribution line (60) comprises a gas distribution impurity removal device comprising a first waste heat treatment device and the pre-converter assembly.

9. The water gas shift system according to claim 8, wherein the pre-converter assembly comprises a start-up nitrogen heat exchanger (100), the first tube pass discharge port (11) is communicated with the gas inlet (3) through a tube pass of the start-up nitrogen heat exchanger (100), the water gas shift system comprises a fan (110), the fan (110), a gas distribution impurity removing device, a waste heat treatment assembly and an ammonia washing tower (77) are sequentially communicated in a circulating mode, and a circulating pipeline pressure regulating valve (121) is arranged between the fan (110) and the ammonia washing tower (77).

10. A method of preheating a water gas shift system as claimed in claim 9, comprising:

s1: filling nitrogen with a first set pressure into the tube side inlet end of the start-up nitrogen heat exchanger (100);

s2: starting a fan (110);

s3: filling a heating medium into the shell pass of the start-up nitrogen heat exchanger (100);

s4: and filling nitrogen with a second set pressure into the air inlet (3).

Technical Field

The invention relates to the field of coal chemical industry, in particular to a water gas shift system and a preheating method thereof.

Background

The coal-to-olefin is used as a clean and efficient coal utilization project, and a plurality of enterprises are built and put into production at present in China. Because the hydrogen-carbon ratio required by the coal-to-olefin in the methanol synthesis process is 2.05-2.15, the conversion device is designed to be partial conversion for meeting the requirement, but the sulfur standard exceeding of the purified gas of the low-temperature methanol washing system is found in the actual production operation process, and meanwhile, the ash deposition of the low-temperature methanol washing regeneration system is serious. The reason for the overproof sulfur in the purified gas is analyzed, and the content of carbonyl sulfur in the purified gas is higher. Because the conversion device adopts partial conversion, about 45 percent of coarse water gas needs to participate in the adjustment of the hydrogen-carbon ratio of the system, the coarse water gas is mixed with the conversion gas and enters the low-temperature methanol washing device after being subjected to waste heat recovery without passing through the conversion furnace, so that the absorption and regeneration load of the low-temperature methanol washing system on carbonyl sulfur are increased, the index of total sulfur of purified gas is further influenced, and meanwhile, the carbonyl sulfur content in the low-temperature methanol washing regenerated acid gas is higher, the low-temperature methanol washing regenerated acid gas enters the sulfur recovery system, the load of a tail gas hydrogenation reactor is increased, and the stable production of the sulfur recovery device.

Because 45% of coarse water gas does not pass through the shift converter, when the gasification device is started and stopped, or a large amount of coal ash can be brought into the low-temperature methanol washing system under the condition that the load is greatly fluctuated, the heat exchanger tube bundle of the low-temperature methanol washing system is blocked or the heat exchange effect is reduced, in addition, low-temperature methanol washing pumps can be caused, particularly, inlet filter screen blockage occurs to the pump of the regeneration system, the filter screen is frequently washed, and the stable production of low-temperature methanol washing is not facilitated.

Disclosure of Invention

The invention aims to solve the problem that the prior gas distribution pipeline has no carbonyl sulfide removal device, which causes serious pollution to the subsequent process.

In order to achieve the above object, in one aspect, the present invention provides a water gas shift system, including a gas distribution line, a pre-shift furnace assembly connected in series to the gas distribution line, the pre-shift furnace assembly including a pre-shift furnace, the pre-shift furnace including a furnace shell and a first catalyst arranged in the furnace shell for hydrolyzing carbonyl sulfide, a gas inlet and a gas outlet respectively arranged at two ends of the furnace shell, so that a feed gas entering from the gas inlet passes through the first catalyst and then is discharged from the gas outlet.

Preferably, the first catalyst comprises a mixed catalyst and a shift catalyst for hydrolyzing carbonyl sulfide shift feed gas, which are sequentially arranged in the axial direction of the furnace shell, and the mixed catalyst comprises a carbonyl sulfide hydrolysis catalyst and an oxygen removal catalyst.

Preferably, the pre-converter comprises ceramic balls which are axially clamped with the mixed catalyst and the conversion catalyst on the converter shell.

Preferably, one end of the porcelain ball, which is far away from the first catalyst, is provided with a wire mesh for fixing the porcelain ball.

Preferably, the pre-converter assembly comprises a first shell-and-tube heat exchanger and the pre-converter, a first tube pass discharge port of the first shell-and-tube heat exchanger is communicated with the air inlet, a first shell pass feed port of the first tube pass heat exchanger is communicated with the air outlet, and the pre-converter assembly is arranged to be connected in series on the air distribution pipeline through the first tube pass feed port and the first shell pass discharge port.

Preferably, the pre-converter assembly comprises a heat exchanger bypass pipeline and a pre-converter bypass pipeline, two ends of the heat exchanger bypass pipeline are respectively communicated with the first tube side feed port and the first tube side discharge port, two ends of the pre-converter bypass pipeline are respectively communicated with the air inlet and the air outlet, a heat exchanger bypass pipeline valve is arranged on the heat exchanger bypass pipeline, a pre-converter bypass pipeline valve is arranged on the pre-converter bypass pipeline, and a first tube side discharge port valve is arranged on the first tube side discharge port.

Preferably, the water gas shift system comprises a raw material gas treatment device, a raw material gas shift device, a waste heat treatment assembly and an ammonia washing tower which are sequentially communicated, and the raw material gas shift device comprises a shift pipeline and the gas distribution pipeline which are connected in parallel.

Preferably, the gas distribution pipeline comprises a gas distribution impurity removing device, and the gas distribution impurity removing device comprises a first waste heat treatment device and the pre-converter assembly.

Preferably, the pre-converter assembly comprises a start-up nitrogen heat exchanger, the first tube pass discharge port is communicated with the air inlet through the tube pass of the start-up nitrogen heat exchanger, the water gas conversion system comprises a fan, the gas distribution impurity removing equipment, the waste heat treatment assembly and the ammonia washing tower are sequentially communicated in a circulating mode, and a circulating pipeline pressure regulating valve is arranged between the fan and the ammonia washing tower.

In a second aspect, the invention provides a method of preheating a water gas shift system according to the invention, comprising:

s1: filling nitrogen with a first set pressure into the tube pass inlet end of the start-up nitrogen heat exchanger;

s2: starting a fan;

s3: filling a heating medium into the shell pass of the start-up nitrogen heat exchanger;

s4: the inlet is charged with nitrogen at a second set pressure.

According to the water gas shift system, the gas distribution pipeline is connected with the pre-changing furnace assembly in series, the pre-changing furnace assembly comprises the pre-changing furnace, the furnace shell contains the first catalyst for hydrolyzing carbonyl sulfide, the carbonyl sulfide is prevented from entering a subsequent process flow along with water gas, the absorption and regeneration load of a subsequent low-temperature methanol washing system on the carbonyl sulfide is reduced, the total sulfur content of purified gas is further reduced, high-content carbonyl sulfide in acid gas regenerated by low-temperature methanol washing is prevented from entering a sulfur recovery system, the load of a tail gas hydrogenation reactor is reduced, and the stability of a sulfur recovery device is improved.

Drawings

FIG. 1 is a schematic structural view of a pre-shift oven according to an embodiment of the present invention;

FIG. 2 is a schematic structural view of a pre-furnace assembly according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of the high water-gas ratio water gas shift system of the present invention;

FIG. 4 is a schematic representation of the configuration of the low water-gas ratio water gas shift system of the present invention;

FIG. 5 is a schematic diagram of a preheat system configuration for the water gas shift system shown in FIG. 3;

FIG. 6 is a schematic diagram of the preheat system configuration of the water gas shift system shown in FIG. 4.

Description of the reference numerals

1-a pre-shift furnace, 2-a furnace shell, 3-an air inlet, 4-an air outlet, 5-a mixed catalyst, 6-a shift catalyst, 7-ceramic balls, 8-wire netting, 10-a first shell-and-tube heat exchanger, 11-a first tube pass discharge port, 12-a first shell pass feed port, 13-a first shell pass discharge port, 14-a first tube pass feed port, 15-a first tube pass discharge port valve, 20-a pre-shift furnace bypass pipeline, 21-a heat exchanger bypass pipeline, 22-a pre-shift furnace bypass pipeline valve, 23-a heat exchanger bypass pipeline valve, 31-an air inlet valve, 41-an air outlet valve, 50-a shift system feed pipeline, 51-a shift system feed port valve, 52-a raw material gas separator, 53-a raw material gas filter, 60-a gas distribution pipeline, 61-a first water gas waste heat boiler, 62-a third heat exchanger, 63-a first water separator, 64-a raw material gas rough regulating valve, 65-a raw material gas fine regulating valve, 70-a low-pressure waste heat boiler, 71-a fourth water separator, 72-a seventh heat exchanger, 73-an eighth heat exchanger, 74-a fifth water separator, 75-a ninth heat exchanger, 76-a tenth heat exchanger, 77-an ammonia washing tower, 78-a conversion system discharge pipeline, 79-an ammonia washing water feeding pipeline, 80-a conversion pipeline, 81-a second water gas boiler, 82-a fourth heat exchanger, 83-a second water separator, 84-a second tube pass heat exchanger, 85-a fifth heat exchanger, 86-a conversion furnace, 87-a first conversion waste heat boiler, 88-a sixth heat exchanger, 89-a second transformation waste heat boiler, 90-a third water separator, 100-a start-up nitrogen heat exchanger, 101-a start-up nitrogen heat exchanger tube pass feeding port, 102-a start-up nitrogen heat exchanger tube pass discharging port, 103-a start-up nitrogen heat exchanger shell pass feeding port, 104-a start-up nitrogen heat exchanger shell pass discharging port, 105-a nitrogen pre-pressing pipeline, 110-a fan, 111-a circulating nitrogen feeding pipe, 120-a torch removing pipeline, 121-a circulating pipeline pressure regulating valve and 130-a gas regulating pipeline.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The invention provides a water gas shift system, which comprises a gas distribution pipeline 60, wherein a pre-changing furnace assembly is connected in series on the gas distribution pipeline 60, the pre-changing furnace assembly comprises a pre-changing furnace 1, the pre-changing furnace 1 comprises a furnace shell 2 and a first catalyst which is arranged in the furnace shell 2 and is used for hydrolyzing carbonyl sulfide, and two ends of the furnace shell 2 are respectively provided with a gas inlet 3 and a gas outlet 4, so that raw material gas entering from the gas inlet 3 passes through the first catalyst and then is discharged from the gas outlet 4.

According to the water gas shift system, the gas distribution pipeline is connected with the pre-changing furnace assembly in series, the pre-changing furnace assembly comprises the pre-changing furnace, the furnace shell contains the first catalyst for hydrolyzing carbonyl sulfide, the carbonyl sulfide is prevented from entering a subsequent process flow along with water gas, the absorption and regeneration load of a subsequent low-temperature methanol washing system on the carbonyl sulfide is reduced, the total sulfur content of purified gas is further reduced, high-content carbonyl sulfide in acid gas regenerated by low-temperature methanol washing is prevented from entering a sulfur recovery system, the load of a tail gas hydrogenation reactor is reduced, and the stability of a sulfur recovery device is improved. A pre-variable furnace flare torch pipeline is arranged at the gas outlet 4 of the pre-variable furnace 1, and a pre-variable furnace flare torch valve is arranged on the pre-variable furnace flare torch pipeline.

Preferably, the first catalyst comprises a mixed catalyst 5 and a shift catalyst 6 for hydrolyzing carbonyl sulfide shift feed gas, which are sequentially arranged in the axial direction inside the furnace shell 2, and the mixed catalyst 5 comprises a carbonyl sulfide hydrolysis catalyst and an oxygen removal catalyst.

The shift catalyst 6 is a cobalt-molybdenum catalyst which has the functions of hydrolyzing carbonyl sulfide and shifting carbon monoxide and water into carbon dioxide and hydrogen, and can adjust the carbon-hydrogen ratio on the gas distribution pipeline. The hybrid catalyst 5 includes a carbonyl sulfide hydrolysis catalyst and an oxygen removal catalyst, and can hydrolyze carbonyl sulfide and remove impurity oxygen in water gas. The shift catalyst 6 has a shift rate of 1 to 3%.

Preferably, the pre-changing furnace 1 comprises ceramic balls 7 which axially clamp the mixed catalyst 5 and the transformation catalyst 6 on the furnace shell 2. As shown in fig. 1, the ceramic balls 7 adsorb metal ions such as calcium ions and magnesium ions, arsenic, oxygen, and the like in the water gas.

Preferably, an iron wire 8 for fixing the ceramic ball 7 is arranged at one end of the ceramic ball 7 away from the first catalyst. The wire mesh 8 is used to fix the first catalyst and the ceramic ball position.

Preferably, the pre-converter assembly comprises a first shell-and-tube heat exchanger and the pre-converter 1, a first tube pass discharge port 11 of the first shell-and-tube heat exchanger 10 is communicated with the gas inlet 3, a first shell pass feed port 12 of the first shell-and-tube heat exchanger 10 is communicated with the gas outlet 4, and the pre-converter assembly is arranged to be connected in series on the gas distribution pipeline 60 through a first tube pass feed port 14 and a first shell pass discharge port 13. The shift reaction, the oxygen removal reaction, and the carbonyl sulfide hydrolysis reaction inside the pre-shift furnace 1 are exothermic reactions, and a higher temperature is required for the first catalyst to act. Therefore, the gas discharged from the pre-changing furnace is used as the gas entering the pre-changing furnace for heating by the pre-changing furnace assembly, and the reaction rate in the pre-changing furnace 1 can be effectively improved.

Preferably, the pre-variable furnace assembly comprises a heat exchanger bypass pipeline 21 and a pre-variable furnace bypass pipeline 20, two ends of the heat exchanger bypass pipeline 21 are respectively communicated with the first tube side feed inlet 14 and the first tube side discharge outlet 11, two ends of the pre-variable furnace bypass pipeline 20 are respectively communicated with the air inlet 3 and the air outlet 4, a heat exchanger bypass pipeline valve 23 is arranged on the heat exchanger bypass pipeline 21, a pre-variable furnace bypass pipeline valve 22 is arranged on the pre-variable furnace bypass pipeline 20, and a first tube side discharge outlet 15 is arranged on the first tube side discharge outlet 11.

Whether the water gas entering the pre-shift furnace 1 is heated by the first shell-and-tube heat exchanger is determined to some extent by the communication of the heat exchanger bypass line 21. If the temperature of the pre-converter 1 is too high, the heat exchanger bypass pipeline valve 23 is opened, the first tube pass discharge port valve 15 is closed, and the water gas enters the pre-converter 1 without passing through the first shell-and-tube heat exchanger, so that the temperature of the pre-converter 1 can be effectively reduced. If the temperature of the pre-changing furnace 1 is low, the bypass pipeline valve 23 of the heat exchanger is closed, the first tube pass discharge port valve 15 is opened, and then the water gas enters the pre-changing furnace 1 through the first shell-and-tube heat exchanger. The heat exchanger bypass line valve 23 or the first tube side outlet valve 15 can also be adjusted to adjust the amount of water and coal gas entering the pre-variable furnace 1. When the catalyst and the porcelain balls in the pre-changing furnace 1 need to be replaced or need to be overhauled, the bypass pipeline 20 of the pre-changing furnace 1 is convenient to cut when the pre-changing furnace 1 needs to be overhauled and replaced. An air inlet valve 31 and an air outlet valve 41 are respectively arranged at an air inlet 3 and an air outlet 4 of the pre-changing furnace 1, and blind plates are arranged at the positions of the air inlet valve 31 and the air outlet valve 41 and used for cutting and isolating the pre-changing furnace 1.

Preferably, the water gas shift system comprises a raw material gas processing device, a raw material gas shift device, a waste heat processing assembly and an ammonia washing tower 77 which are sequentially communicated, wherein the raw material gas shift device comprises a shift pipeline 80 and the gas distribution pipeline 60 which are connected in parallel. The raw gas treatment apparatus includes a raw gas separator 52 for removing moisture from the water gas entering from the shift system feed line 50, and a raw gas filter 53 for removing impurities from the water gas.

The waste heat treatment assembly comprises a low-pressure waste heat boiler 70, a fourth water separator 71, a third water separation assembly, a fifth water separator 74, a ninth heat exchanger 75 and a tenth heat exchanger 76 which are sequentially communicated, and the low-pressure waste heat boiler 70. Wherein the low pressure waste heat boiler 70, the ninth heat exchanger 75 and the tenth heat exchanger 76 are all used for cooling the shifted gas so as to separate out water in the water gas, and the fifth water separator 74 and the fourth water separator 71 are used for separating and removing the separated water. The third water separation assembly comprises a seventh heat exchanger 72 and an eighth heat exchanger 73 which are connected in parallel and used for cooling the conversion gas, and the parallel connection mode enables the moisture of the conversion gas to be fully separated out through the cooling of the two heat exchangers. The ammonia scrubber 77 is used to remove ammonia gas from the shifted gas.

As shown in fig. 3 and 4, the shift line 80 includes a second water separating assembly, a second water separator 83, a shift converter assembly, a first shift waste heat boiler 87, a sixth heat exchanger 88, a second shift waste heat boiler 89 and a third water separator 90 which are connected in sequence, wherein the second water separating assembly includes a second water gas waste heat boiler 81 and a fourth heat exchanger 82 which are connected in parallel, the shift converter assembly includes a second tube-pass heat exchanger 84 and a shift converter 86, a tube-pass gas outlet of the second tube-pass heat exchanger 84 is connected with a shell-pass gas inlet of the second tube-pass heat exchanger 84 through the shift converter 86, and the second tube-pass heat exchanger 84 is used for heating the water gas fed into the shift converter 86 by using the water gas discharged from the shift converter 86; the outlet end of the shift converter 86 is connected to the shell-side inlet of the second tube-side heat exchanger 84 through a fifth heat exchanger 85. The second water gas waste heat boiler 81, the fourth heat exchanger 82, the fifth heat exchanger 85, the first shift waste heat boiler 87, the sixth heat exchanger 88 and the second shift waste heat boiler 89 are all used for reducing the temperature of the water gas so as to analyze out the water in the water gas, and the second water separator 83 and the third water separator 90 are used for removing the separated water. The shift reaction is carried out in the shift converter to convert carbon monoxide and water into carbon dioxide and hydrogen, so as to achieve the purpose of adjusting the carbon-hydrogen ratio.

Preferably, the gas distribution line 60 comprises a gas distribution impurity removal device comprising a first waste heat treatment apparatus and the pre-converter assembly. As shown in fig. 3 and 4, the first waste heat treatment device comprises a first water separating assembly and a first water separator 63 which are connected in sequence, the first water separating assembly comprises a first water gas waste heat boiler 61 and a third heat exchanger 62 which are connected in parallel on a water gas conveying pipeline, the first water gas waste heat boiler 61 and the third heat exchanger 62 are used for cooling water gas so as to separate out water in the water gas, and the first water separator 63 is used for removing water separated out from the water gas.

Fig. 3 is a schematic structural diagram of the water gas shift system with high water-gas ratio according to the present invention, in the direction of water gas transportation, the pre-converter assembly and the first waste heat treatment device are sequentially disposed, at this time, the water gas directly enters the pre-converter assembly, and the catalyst content in the pre-converter is adjusted according to the water gas with high water-gas ratio. Fig. 4 is a schematic structural diagram of the water gas shift system with low water-gas ratio according to the present invention, in the direction of water gas transportation, the first waste heat treatment device and the pre-converter assembly are sequentially disposed, at this time, the water gas enters the pre-converter assembly after being analyzed by the first waste heat treatment device, and the catalyst content in the pre-converter is adjusted according to the water gas with low water-gas ratio.

And the gas distribution pipeline 60 is sequentially provided with a gas distribution impurity removing device and a gas distribution adjusting device in the conveying direction of the raw material gas, the gas distribution adjusting device comprises a raw material gas rough adjusting valve 64 and a raw material gas fine adjusting valve 65 which are connected in parallel on the water gas conveying pipeline, and the large-amplitude adjustment and fine adjustment of the conveying amount of the water gas can be realized.

Preferably, the pre-converter assembly comprises a start-up nitrogen heat exchanger 100, the first tube pass discharge port 11 is communicated with the air inlet 3 through the tube pass of the start-up nitrogen heat exchanger 100, the water gas shift system comprises a fan 110, the gas distribution impurity removing device, the waste heat treatment assembly and the ammonia washing tower 77 are sequentially communicated in a circulating manner, and a circulating pipeline pressure regulating valve 121 is arranged between the fan 110 and the ammonia washing tower 77. The lines of the water gas shift system need to be purged with nitrogen prior to start-up to protect the lines and equipment of the system. Before starting up, the pre-changing furnace 1 needs to reach the temperature and pressure required by the reaction in the pre-changing furnace, and the catalyst needs to reach a certain temperature. The nitrogen gas filled in the pre-variable furnace can be circulated by the fan 110 to protect the water gas shift system, the start-up nitrogen gas heat exchanger 100 can heat the nitrogen gas filled in the pre-variable furnace to reach the start-up temperature of the pre-variable furnace 1, and after the temperature of the pre-variable furnace 1 is raised, the nitrogen gas with the second pressure is filled to reach the start-up pressure of the pre-variable furnace 1.

In a second aspect, the invention provides a method of preheating a water gas shift system according to the invention, comprising:

s1: filling nitrogen with a first set pressure into the tube pass inlet end of the start-up nitrogen heat exchanger 100;

s2: starting the fan 110;

s3: filling a heating medium into the shell pass of the start-up nitrogen heat exchanger 100;

s4: the inlet 3 is charged with nitrogen gas at a second set pressure.

In step 1, a first set pressure of nitrogen is charged into the tube side inlet end of the start-up nitrogen heat exchanger 100, so that the nitrogen enters the circulation line shown in fig. 5 and 6; in step 2, the fan 110 is started to circulate nitrogen in the circulation line to protect the circulation line; in the step 3, filling a heating medium into the shell pass of the start-up nitrogen heat exchanger 100 to heat the circulating gas and preheat the pre-changing furnace 1; in step 4, after the temperature of the pre-variable furnace 1 is raised, the heating medium and the nitrogen gas with the first pressure are stopped, and the nitrogen gas with the second set pressure is filled into the inlet end (i.e. the air inlet 3) of the pre-variable furnace 1, so that the pre-variable furnace 1 reaches the pressure required by the start-up. The catalyst can reach the initial activity of the reaction by heating the catalyst; the temperature of the water gas is reached, so that a large amount of water is prevented from being analyzed out due to the fact that the water gas is cooled, and the catalyst is pulverized due to the fact that the catalyst is soaked in the water gas; the temperature is raised according to the temperature raising rate, so that the catalyst is prevented from being damaged due to the fact that the rigid structure of the catalyst is damaged when the catalyst suddenly encounters high temperature; the pressure of the pre-changing furnace 1 is increased to reach the pressure of water gas, and the damage to the catalyst caused by overlarge front-back pressure difference of the pre-changing furnace 1 is avoided.

As shown in fig. 5 and 6, the circulating nitrogen inlet pipe 111 is connected to the blower 110, and the blower 110 may be used to fill nitrogen gas into the pipeline. The first set pressure of nitrogen may be 0.7MPa and the second set pressure of nitrogen may be 8.0 MPa.

A flare removing pipeline 120 is arranged on a pipeline between the ammonia washing tower 77 and the fan 110, and a circulating pipeline pressure regulating valve 121 is arranged on the flare removing pipeline 120 and used for controlling the pressure of the temperature rise of the conversion system; the outlet pipeline 4 of the pre-changing furnace 1 is provided with a torch removing pipeline, and the torch removing pipeline is provided with a valve for releasing pressure or replacing combustible gas during maintenance of the pre-changing furnace. The shift system feed line 50 is provided with a shift system feed port valve 51 to control the opening and closing of the water gas shift system. A nitrogen pre-pressure pipeline 105 is arranged at the tube side feed inlet 101 of the start-up nitrogen heat exchanger to fill nitrogen into the pre-changing furnace. Superheated steam is filled into the shell pass of the start-up nitrogen heat exchanger 100 from the shell pass feeding hole 103 of the start-up nitrogen heat exchanger to heat nitrogen, so that the pre-changing furnace is heated. The superheated steam is discharged from a shell pass discharge port 104 of the start-up nitrogen heat exchanger.

As shown in fig. 5, the opening cycle is performed by charging 0.4MPa nitrogen gas into the tube side inlet end of the start-up nitrogen gas heat exchanger 100, and pressurizing the inside of the cycle to 0.3 MPa; after the nitrogen circulating fan is confirmed to have the starting condition, the circulating fan is started according to the operation rules to carry out nitrogen circulation, and the circulation volume is controlled to be 10000-20000 Nm³And/h, controlling the pressure of the pressure regulating valve 121 of the circulating pipeline to be 0.3-0.4 MPa.

Checking and confirming that the start-up nitrogen heater has the commissioning condition; putting the start-up nitrogen heat exchanger 100 into service, introducing steam into the shell pass feed inlet 103 of the full-start-up nitrogen heat exchanger, and heating the pre-furnace catalyst at a heating rate of less than or equal to 50 ℃/h; adjusting the heating steam quantity in time; and raising the temperature of the catalyst to 220-250 ℃ to wait for introducing process gas.

After the air guide of the transformation part is finished, the system is stably adjusted; starting to use the gas distribution part; the process gas flow of the gas distribution part is slowly increased through the gas distribution adjusting device, so that the temperature fluctuation of a bed layer of the shift converter is prevented; along with the increase of the gas flow of the gas distribution part, the liquid level and the pressure of each waste boiler are well monitored; monitoring the liquid level of each separation tank; and after the gas distribution part is put into use and the system is stably adjusted, preparing to put into use the pre-changing furnace.

Charging nitrogen with a second set pressure into the inlet end of the pre-changing furnace 1, confirming that the pre-changing furnace is boosted to 5.0MPa through high-pressure nitrogen, and stopping charging the nitrogen; and confirming that the inlet temperature of the pre-change furnace is higher than the saturation temperature of the water gas by more than 20 ℃ and 240-250 ℃.

And (3) starting gas guiding of the pre-variable furnace, opening the gas outlet valve 41, opening the gas inlet valve 31 of the pre-variable furnace after the outlet valve 41 of the pre-variable furnace is fully opened, closing the bypass pipeline valve 22 of the pre-variable furnace, and leading the water gas into the pre-variable furnace 1 so as to pay close attention to the temperature change of the bed layer of the pre-variable furnace.

After the water gas is introduced into the pre-shift furnace, each process parameter of the system is adjusted in time, the hydrogen-carbon ratio is adjusted to be within a design range, and the pressure of the system is controlled through a pressure regulating valve 121 of a circulating pipeline.

As shown in fig. 6, the opening cycle is performed by charging 0.4MPa nitrogen gas into the tube side inlet end of the start-up nitrogen gas heat exchanger 100, and pressurizing the inside of the cycle to 0.3 MPa; after the nitrogen circulating fan is confirmed to have the starting condition, the circulating fan is started according to the operation rules to carry out nitrogen circulation, and the circulation volume is controlled to be 10000-20000 Nm³And/h, controlling the pressure of the pressure regulating valve 121 of the circulating pipeline to be 0.3-0.4 MPa.

Checking and confirming that the start-up nitrogen heater has the commissioning condition; putting the start-up nitrogen heat exchanger 100 into service, introducing steam into the shell pass feed inlet 103 of the full-start-up nitrogen heat exchanger, and heating the pre-furnace catalyst at a heating rate of less than or equal to 50 ℃/h; adjusting the heating steam quantity in time; and raising the temperature of the catalyst to 220-250 ℃ to wait for introducing process gas.

After the air guide of the transformation part is finished, the system is stably adjusted; starting to use the gas distribution part; the process gas flow of the gas distribution part is slowly increased through the gas distribution adjusting device, so that the temperature fluctuation of a bed layer of the shift converter is prevented; along with the increase of the gas flow of the gas distribution part, the liquid level and the pressure of each waste boiler are well monitored; monitoring the liquid level of each separation tank; and after the gas distribution part is put into use and the system is stably adjusted, preparing to put into use the pre-changing furnace.

Charging nitrogen with a second set pressure into the inlet end of the pre-changing furnace 1, confirming that the pre-changing furnace is boosted to 5.0MPa through high-pressure nitrogen, and stopping charging the nitrogen; and confirming that the inlet temperature of the pre-change furnace is higher than the saturation temperature of the water gas by more than 20 ℃ and 210-220 ℃.

And (3) starting gas guiding of the pre-variable furnace, opening the gas outlet valve 41, opening the gas inlet valve 31 of the pre-variable furnace after the outlet valve 41 of the pre-variable furnace is fully opened, closing the bypass pipeline valve 22 of the pre-variable furnace, and leading the water gas into the pre-variable furnace 1 so as to pay close attention to the temperature change of the bed layer of the pre-variable furnace.

After the water gas is introduced into the pre-shift furnace, each process parameter of the system is adjusted in time, the hydrogen-carbon ratio is adjusted to be within a design range, and the pressure of the system is controlled through a pressure regulating valve 121 of a circulating pipeline.

The cutting operation of the pre-changing furnace is as follows:

closing the gas inlet valve 31 of the pre-changing furnace, simultaneously opening the bypass pipeline valve 22 of the pre-changing furnace, closely paying attention to the change gas quantity, the change of the bed temperature of the shift converter and the hydrogen-carbon ratio of the system, closing the first pipe pass discharge port valve 15 in time for adjustment, and avoiding the large-amplitude fluctuation of the system; closely paying attention to the pressure and liquid level of each waste boiler and the liquid level of each separator, and tracking and adjusting the waste boilers in time.

When the inlet valve 31 of the pre-variable furnace is closed and the bypass pipeline valve 22 of the pre-variable furnace is fully opened, the outlet valve 41 of the pre-variable furnace is closed, the flare valve of the pre-variable furnace is opened for pressure relief, and the pressure relief rate is controlled to be less than or equal to 0.1 MPa/min; and when the pressure of the pre-variable furnace is released, 0.7MPa nitrogen is filled into the gas inlet 3 of the pre-variable furnace to replace the pre-variable furnace, and the content of combustible gas is analyzed to be less than or equal to 0.5 v/v% to be qualified.

And after the replacement is finished, blind plates at the inlet and the outlet of the pre-changing furnace are guided, the pre-changing furnace is isolated from the system, and the ceramic balls and the catalyst are replaced for the pre-changing furnace when the temperature of a bed layer of the pre-changing furnace is reduced to 40-50 ℃.

The process gas and the feed gas are water gas.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention. Including each of the specific features, are combined in any suitable manner. The invention is not described in detail in order to avoid unnecessary repetition. Such simple modifications and combinations should be considered within the scope of the present disclosure as well.