A device and method for deoxidation and desulfurization of converter gas

Abstract

The present invention belongs to the technical field of deoxidation and desulfurization, and discloses a device and method for deoxidation and desulfurization of converter gas. The present invention adds a cold shock pipeline to allow gas to enter from the top and bottom of the deoxidation reactor respectively, and at the same time, by controlling the valve opening, adjusts the converter gas flow entering the bottom and the top, so that the top temperature is controlled at 70°C, the hot spot temperature of the catalyst bed of the deoxidation reactor does not exceed 190°C, and the average temperature does not exceed 150°C. The processing capacity of the deoxidation reactor is improved. A baffle rod shell and tube heat exchanger is selected to replace the original inlet baffle and baffle type purified gas water cooler, so that the resistance drop of the purifier water cooler is reduced by 30KPa, and the overall pressure difference of the system is lower than 150KPa. The deoxidized gas after passing through the device of the present invention does not need to be divided into a part to enter the converter gas circulation compressor for recycling. The compressor is stopped, and the resistance drop of the deoxidation reactor is reduced by 30KPa, which reduces energy consumption and also reduces the production cost of the device.

Description

Technical Field

[0001] The invention belongs to the technical field of deoxidation and desulfurization, and specifically relates to a device and method for deoxidation and desulfurization of converter coal gas. Background Art

[0002] At present, when ethylene glycol is produced using converter gas and coke oven gas as raw materials, 58,000 Nm of converter gas is consumed per hour. 3 , the CO content in converter gas is 45-50%, the oxygen content is ≤1%, and the organic sulfur content such as COS and dimethyl sulfide is ≤15mg / Nm 3 . In order to meet the requirements of ethylene glycol production, the oxygen content in the converter gas needs to be reduced to below 30ppm, and the total sulfur content is less than 0.1ppm. The converter gas deoxidation and fine desulfurization process adopts the process route of COS hydrolysis, primary desulfurization, deoxidation and fine desulfurization. The overall resistance drop of the design system is ≤150kpa. The deoxygenation reactor adopts an internal heat exchange type uniform temperature reactor, the hot spot temperature of the catalyst bed is ≤180℃, and the average bed temperature is ≤150℃.

[0003] The existing deoxidation and desulfurization process is mainly as follows: the converter gas passes through the converter gas heat exchanger and heats up the deoxidized converter gas to 60°C, and then enters the hydrolysis desulfurization tower for desulfurization. The gas coming out of the top of the hydrolysis desulfurization tower is mixed with the deoxidized circulating gas through the start-up heater, and then enters the deoxidation reactor from the bottom to remove oxygen from the converter gas. The deoxidized gas is divided into two parts, one part is used as the deoxidized circulating gas, which is pressurized by the converter gas circulation compressor and recycled, and the other part passes through the converter gas heat exchanger and heat exchange with the raw gas to cool it down, and then cools to 40°C through the purified gas water cooler, and then enters the fine desulfurization tower from the bottom of the tower to remove the residual mercaptans and dimethyl disulfide in the gas.

[0004] In the actual operation of this process, when the oxygen content of the deoxygenation reactor inlet exceeds 0.5%, the hot spot temperature of the deoxygenation reactor catalyst bed reaches above 190°C, and the average temperature of the catalyst bed reaches above 160°C; the overall resistance drop of the system reaches up to 200kpa, far exceeding the design index requirements. In order to ensure the safe operation of the device, it can only be operated by reducing the production load. Therefore, it has certain limitations, which are mainly reflected in the following points.

[0005] 1. The processing capacity of the existing deoxygenation reactor has high requirements for the oxygen content index in the imported converter gas, which cannot be higher than 0.5%. In order to control the imported oxygen content, the converter gas circulation compressor needs to be operated to increase the circulation volume, which can dilute the oxygen content on the one hand and increase the reactor bed space velocity on the other hand to take away the reaction heat. The rated power of the compressor is 420KW, and the operating energy consumption is high, which increases the production cost; at the same time, it increases the overall pressure difference of the system.

[0006] 2. The reaction heat of the catalyst bed in the deoxygenation reactor can only be taken away by increasing the circulation volume through the circulation compressor. The adjustment means are single and the energy consumption is high. When the oxygen content at the inlet of the deoxygenation reactor exceeds 0.5%, the hot spot temperature of the catalyst bed is too high, and the production load can only be reduced, affecting the overall production capacity of the device.

[0007] 3. The deoxidation catalyst is loaded in the shell side of the reactor. The converter gas enters from the bottom tube side of the reactor and exchanges heat with the hot converter gas that has been deoxidized in the shell side. The heat exchange effect cannot be effectively controlled, resulting in an extremely high temperature when entering the shell side and starting the reaction, which leads to an extremely high hot spot temperature of the catalyst bed.

[0008] 4. There are problems with the design structure of the purified air water cooler. The original design used imported baffles and deflectors, which resulted in a large resistance drop of the purified air water cooler, exceeding 40kpa, causing a large overall resistance drop in the system.

[0009] Therefore, it is of great significance to provide a new device and method for converter gas deoxidation and desulfurization to reduce the bed temperature and system resistance of the deoxidation reactor, increase the service life of the deoxidation catalyst, and increase the operating load of the converter gas deoxidation and desulfurization device. Summary of the invention

[0010] In view of the above problems, the present invention provides a device and method for converter gas deoxidation and desulfurization. The device and method can reduce the bed temperature and system resistance of the deoxidation reactor of the existing method, increase the service life of the deoxidation catalyst, and increase the operating load of the converter gas deoxidation and desulfurization device.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] The present invention provides a device for deoxidation and desulfurization of converter gas, which mainly comprises: a deoxidation reactor, a cold shock pipeline, a deoxidation reactor inlet pipeline, a cold shock pipeline regulating valve, a deoxidation reactor inlet pipeline regulating valve, a purification water cooler, a converter gas heat exchanger, a hydrolysis desulfurization start-up heater, a hydrolysis desulfurization tower, a start-up heater, and a fine desulfurization tower;

[0013] Among them, the air inlet of the converter gas heat exchanger is connected to the converter gas, the air outlet of the converter gas heat exchanger is connected to the air inlet of the hydrolysis desulfurization start-up heater, the air outlet of the hydrolysis desulfurization start-up heater is connected to the air inlet at the bottom of the hydrolysis desulfurization tower, the air outlet at the top of the hydrolysis desulfurization tower is connected to the air inlet of the start-up heater, the air outlet of the start-up heater is divided into two branches, one is connected to the top air inlet of the deoxidation reactor through a cold shock pipeline, and the other is connected to the air inlet at the bottom of the deoxidation reactor through a deoxidation reactor inlet pipeline. A cold shock pipeline regulating valve and a deoxidation reactor inlet pipeline regulating valve are respectively arranged on the cold shock pipeline and the deoxidation reactor inlet pipeline, which are used to adjust the converter gas flow entering the top and bottom of the deoxidation reactor respectively; the air outlet at the bottom of the deoxidation reactor is connected to the shell side inlet of the converter gas heat exchanger, the shell side outlet of the converter gas heat exchanger is connected to the shell side inlet of the purified gas water cooler, and the shell side outlet of the purified gas water cooler is connected to the bottom air inlet of the fine desulfurization tower.

[0014] Furthermore, the converter gas can be directly connected to the air inlet of the hydrolysis desulfurization start-up heater without passing through the converter gas heat exchanger; the gas outlet at the bottom of the deoxygenation reactor can also be directly connected to the shell inlet of the purified gas water cooler without passing through the converter gas heat exchanger.

[0015] Furthermore, the cold shock pipeline regulating valve and the deoxygenation reactor inlet pipeline regulating valve are DN600 triple eccentric flange type composite sealing butterfly valves.

[0016] Furthermore, the purification water cooler is a baffle rod shell and tube heat exchanger.

[0017] The present invention also provides a method for deoxidizing and desulfurizing converter gas, comprising the following steps:

[0018] Step 1: After the converter gas passes through the converter gas heat exchanger and the deoxygenated converter gas to raise the temperature to the set temperature, it passes through the hydrolysis desulfurization start-up heater and enters the hydrolysis desulfurization tower from the bottom of the hydrolysis desulfurization tower. Under the action of the lower organic sulfur hydrolysis catalyst, the organic sulfur in the converter gas is hydrolyzed into hydrogen sulfide, and then the H2S and other sulfides in the gas are removed under the action of the upper dual-function fine desulfurizer;

[0019] Step 2: The gas coming out from the top of the hydrolysis desulfurization tower passes through the start-up heater and then enters the deoxygenation reactor from the top and bottom of the deoxygenation reactor to remove oxygen from the converter gas;

[0020] Step 3: The gas deoxygenated by the deoxygenation reactor passes through the converter gas heat exchanger to cool down with the original converter gas, and then passes through the purified gas water cooler to cool down to the set temperature. It then enters the fine desulfurization tower from the bottom of the fine desulfurization tower to remove residual mercaptans and dimethyl disulfide in the gas. The purified gas coming out of the top of the fine desulfurization tower goes to the next process.

[0021] Furthermore, the purifier water cooler in step 3 is a baffled rod shell and tube heat exchanger.

[0022] Furthermore, in the step 2, the gas flow rates entering the deoxygenation reactor from the top and bottom of the deoxygenation reactor are respectively controlled by the cold shock pipeline regulating valve and the deoxygenation reactor inlet pipeline regulating valve, with the specific requirements of controlling the top temperature of the deoxygenation reactor at the catalyst activation temperature; when the oxygen content in the converter gas does not exceed 1.0%, the hot spot temperature of the catalyst bed of the deoxygenation reactor does not exceed 190°C, and the average temperature does not exceed 150°C.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. The present invention adds a cold shock pipeline to allow the gas to enter from the top and bottom of the deoxidation reactor respectively, and at the same time, by controlling the valve opening, the converter gas flow entering the bottom and top is adjusted to achieve the top temperature control at 70°C. When the oxygen content in the converter gas does not exceed 1.0%, the hot spot temperature of the catalyst bed of the deoxidation reactor does not exceed 190°C, and the average temperature does not exceed 150°C.

[0025] 2. After passing through the device of the present invention, the deoxygenated gas does not need to be divided into a part to enter the converter gas circulation compressor for recycling. The compressor stops running, the resistance drop of the deoxygenation reactor drops by 30KPa, and all the deoxygenated gas enters the purified gas water cooler.

[0026] 3. The purifier water cooler of the present invention adopts a baffle rod shell and tube heat exchanger, which replaces the original inlet baffle and baffle type purified gas water cooler, so that the resistance drop of the purifier water cooler is reduced by 30KPa, and the overall pressure difference of the system is lower than 150KPa.

[0027] In summary, the device and method of the present invention can improve the processing capacity of the deoxygenation reactor, reduce energy consumption and device production cost, reduce system resistance drop, and improve the overall production load of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the device for deoxidation and desulfurization of converter gas according to the present invention. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is specifically and detailedly described below in conjunction with the embodiments of the present invention and the accompanying drawings. It should be noted that for ordinary technicians in this field, several modifications and improvements can be made without departing from the principle of the present invention, which should also be regarded as belonging to the protection scope of the present invention.

[0030] Example 1

[0031] A device for deoxidizing and desulfurizing converter gas, such as Figure 1As shown, it mainly includes: deoxygenation reactor 1, cold shock pipeline 2, deoxygenation reactor inlet pipeline 3, cold shock pipeline regulating valve 4, deoxygenation reactor inlet pipeline regulating valve 5, purified water cooler 6, converter gas heat exchanger 7, hydrolysis desulfurization start-up heater 8, hydrolysis desulfurization tower 9, start-up heater 10, and fine desulfurization tower 11.

[0032] The converter gas is connected to the air inlet of the converter gas heat exchanger 7, the air outlet of the converter gas heat exchanger 7 is connected to the air inlet of the hydrolysis desulfurization start-up heater 8, the air outlet of the hydrolysis desulfurization start-up heater 8 is connected to the air inlet at the bottom of the hydrolysis desulfurization tower 9, the top air outlet of the hydrolysis desulfurization tower 9 is connected to the air inlet of the start-up heater 10, the air outlet of the start-up heater 10 is connected to the top air inlet and the bottom air inlet of the deoxidation reactor 1 through two branches of the cold shock pipeline 2 and the deoxidation reactor inlet pipeline 3, respectively. A cold shock pipeline regulating valve 4 and a deoxidation reactor inlet pipeline regulating valve 5 are respectively provided on the converter inlet pipeline 3, which are used to adjust the converter gas flow entering the top and bottom of the deoxidation reactor 1 respectively; the gas outlet at the bottom of the deoxidation reactor 1 is connected to the shell side inlet of the converter gas heat exchanger 7, the shell side outlet of the converter gas heat exchanger 7 is connected to the shell side inlet of the purified gas water cooler 6, the shell side outlet of the purified gas water cooler 6 is connected to the bottom gas inlet of the fine desulfurization tower 11, and the top gas outlet of the fine desulfurization tower 11 leads to the outside of the boundary area for subsequent processes.

[0033] The converter gas can also be directly connected to the air inlet of the hydrolysis desulfurization start-up heater 8 without passing through the converter gas heat exchanger 7; the gas outlet at the bottom of the deoxidation reactor 1 can also be directly connected to the shell side inlet of the purified gas water cooler 6 without passing through the converter gas heat exchanger 7.

[0034] The cold shock pipeline regulating valve 4 and the deoxygenation reactor inlet pipeline regulating valve 5 are DN600 triple eccentric flange type composite sealing butterfly valves.

[0035] The purified water cooler 6 is a baffled rod shell and tube heat exchanger.

[0036] Example 2

[0037] A method for deoxidation and desulfurization of converter gas mainly comprises the following steps:

[0038] Step 1. The converter gas from the upstream process has a flow rate of 58000Nm3 / h, a pressure of 0.9MPa, a CO content of 45-50%, an oxygen content of ≤1%, and an organic sulfur content such as COS and dimethyl sulfide of ≤15mg / Nm 3 After the converter gas heat exchanger 7 heats up the temperature with the deoxidized converter gas to 60°C, it passes through the hydrolysis desulfurization start-up heater 8 and enters the hydrolysis desulfurization tower 9 from the bottom of the hydrolysis desulfurization tower 9.

[0039] Step 2. After the converter gas enters the hydrolysis desulfurization tower 9, the organic sulfur such as COS in the raw gas is first hydrolyzed and converted into H2S under the action of the lower organic sulfur hydrolysis catalyst, and then the H2S and other sulfides in the gas are removed under the action of the upper dual-function fine desulfurizer. The gas coming out of the top of the hydrolysis desulfurization tower 9 passes through the start-up heater 10, and then enters the deoxidation reactor 1 from the bottom and top of the deoxidation reactor 1 through the cold shock pipeline 2 and the deoxidation reactor inlet pipeline 3 respectively to remove oxygen from the converter gas. In order to prevent the catalyst bed of the deoxidation reactor from overheating, the DN600 three-eccentric flange composite sealing butterfly valve on the deoxidation reactor inlet pipeline 3 and the cold shock pipeline 2 controls the inlet flow rate of the deoxidation reactor 1 at the bottom and top to ensure that the top temperature of the deoxidation reactor 1 is controlled at about 70°C (catalyst activation temperature), the hot spot temperature of the catalyst bed does not exceed 190°C, and the average temperature does not exceed 150°C.

[0040] Step 3. The deoxygenated gas is cooled by heat exchange with the raw gas (converter gas) in the converter gas heat exchanger 7, and then cooled to 40°C by the purified gas water cooler (i.e., the baffle rod shell and tube heat exchanger), and then enters the refined desulfurization tower 11 from the bottom of the refined desulfurization tower 11 to remove residual mercaptans and dimethyl disulfide in the gas. The purified gas coming out from the top of the refined desulfurization tower has an oxygen content of ≤30ppm, a total sulfur content of <0.1ppm, and a pressure of ≥0.75MPa, and the post-process is removed.

[0041] The method of the present invention makes the hot spot temperature of the catalyst bed of the deoxygenation reactor not exceed 190°C, and the average temperature not exceed 150°C. The resistance drop of the deoxygenation reactor is reduced by 30KPa, the resistance drop of the purifier water cooler is reduced by 30KPa, and the overall pressure difference of the system is lower than 150KPa. The oxygen content of the converter gas finally obtained is ≤30ppm, the total sulfur content is <0.1ppm, and the pressure is ≥0.75MPa, which meets the production process of ethylene glycol.

Claims

1. A device for deoxidation and desulfurization of converter gas, characterized in that: include: Deoxygenation reactor (1), cold shock pipeline (2), deoxygenation reactor inlet pipeline (3), cold shock pipeline regulating valve (4), deoxygenation reactor inlet pipeline regulating valve (5), purified water cooler (6), converter gas heat exchanger (7), hydrolysis desulfurization start-up heater (8), hydrolysis desulfurization tower (9), start-up heater (10), fine desulfurization tower (11); The converter gas heat exchanger (7) has an air inlet connected to the converter gas, the converter gas heat exchanger (7) has an air outlet connected to the air inlet of the hydrolysis desulfurization start-up heater (8), the hydrolysis desulfurization start-up heater (8) has an air outlet connected to the bottom air inlet of the hydrolysis desulfurization tower (9), the top air outlet of the hydrolysis desulfurization tower (9) is connected to the air inlet of the start-up heater (10), the air outlet of the start-up heater (10) is divided into two branches, one of which is connected to the top air inlet of the deoxidation reactor (1) through the cold shock pipeline (2), and the other is connected to the deoxidation reactor through the deoxidation reactor inlet pipeline (3). The deoxidation reactor (1) is connected to the air inlet at the bottom of the deoxidation reactor (1), and a deoxidation reactor (1) inlet pipeline (3) is provided with a deoxidation reactor (1) inlet regulating valve (4) and a deoxidation reactor (1) inlet regulating valve (5), respectively, for regulating the flow of converter gas entering the top and bottom of the deoxidation reactor (1); the air outlet at the bottom of the deoxidation reactor (1) is connected to the shell side inlet of the converter gas heat exchanger (7), the shell side outlet of the converter gas heat exchanger (7) is connected to the shell side inlet of the purified gas water cooler (6), and the shell side outlet of the purified gas water cooler (6) is connected to the air inlet at the bottom of the fine desulfurization tower (11).

2. The device for deoxidation and desulfurization of converter gas according to claim 1, characterized in that: The converter gas can also be directly connected to the air inlet of the hydrolysis desulfurization start-up heater (8) without passing through the converter gas heat exchanger (7); the air outlet at the bottom of the deoxidation reactor (1) can also be directly connected to the shell side inlet of the purified gas water cooler (6) without passing through the converter gas heat exchanger (7).

3. The device for deoxidation and desulfurization of converter gas according to claim 1, characterized in that: The cold shock pipeline regulating valve (4) and the deoxygenation reactor inlet pipeline regulating valve (5) are DN600 triple eccentric flange type composite sealing butterfly valves.

4. The device for deoxidation and desulfurization of converter gas according to claim 1, characterized in that: The purified water cooler (6) is a baffle rod shell and tube heat exchanger.

5. A method for deoxidation and desulfurization of converter gas, characterized in that: The following steps are involved: Step 1: The converter gas is heated to a set temperature by heat exchange with the deoxygenated converter gas in the converter gas heat exchanger (7), and then passes through the hydrolysis desulfurization start-up heater (8), and enters the hydrolysis desulfurization tower (9) from the bottom of the hydrolysis desulfurization tower (9). Under the action of the lower organic sulfur hydrolysis catalyst, the organic sulfur in the converter gas is hydrolyzed into hydrogen sulfide, and then H2S and other sulfides in the gas are removed under the action of the upper dual-function fine desulfurizer; Step 2: The gas coming out from the top of the hydrolysis desulfurization tower (9) passes through the start-up heater (10) and then enters the deoxygenation reactor (1) from the top and bottom of the deoxygenation reactor (1) to remove oxygen from the converter gas; Step 3: The gas deoxygenated by the deoxygenation reactor (1) passes through the converter gas heat exchanger (7) to exchange heat with the original converter gas for cooling, and then passes through the purified gas water cooler (6) to cool to the set temperature, and then enters the fine desulfurization tower (11) from the bottom of the fine desulfurization tower (11) to remove residual mercaptans and dimethyl disulfide in the gas. The purified gas coming out of the top of the fine desulfurization tower (11) is passed to the next process.

6. The method for deoxidation and desulfurization of converter gas according to claim 5, characterized in that: The purifier water cooler (6) in step 3 is a baffled rod shell and tube heat exchanger.

7. The method for deoxidation and desulfurization of converter gas according to claim 5, characterized in that: In the step 2, the gas flow rates entering the deoxygenation reactor (1) from the top and bottom of the deoxygenation reactor (1) are controlled by the cold shock pipeline regulating valve (4) and the deoxygenation reactor inlet pipeline regulating valve (5) respectively. The specific requirements are that the top temperature of the deoxygenation reactor (1) is controlled at the catalyst activation temperature; when the oxygen content in the converter gas does not exceed 1.0%, the hot spot temperature of the catalyst bed in the deoxygenation reactor (1) does not exceed 190°C, and the average temperature does not exceed 150°C.

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