Desulfurization and dechlorination system for synthesis gas

Abstract

The desulfurization and dechlorination system comprises an alkaline washing tower, an adsorption tower, a heater, a hydrogenation reactor and a desulfurization reactor, the upper end of the alkaline washing tower is communicated with the lower end of the adsorption tower, the upper end of the adsorption tower is communicated with the upper end of the hydrogenation reactor, and the lower end of the hydrogenation reactor is communicated with the upper end of the desulfurization reactor. And a heater is hermetically connected between the adsorption tower and the hydrogenation reactor. Under the cooperation of the alkaline washing tower, the adsorption tower, the hydrogenation reactor and the desulfurization reactor, H2S, COS, NH3, HCN and HCl in the synthesis gas can be effectively removed, the content of H2S, COS, NH3, HCN and HCl is 0.1 ppm or below, and continuous production is achieved in the desulfurization and dechlorination process.

Description

TECHNICAL FIELD

[0001] The utility model relates to desulfurization and dechlorination technical field, especially in synthetic gas is with desulfurization and dechlorination system. BACKGROUND

[0002] Synthetic gas needs to be obtained after synthetic procedure, and needs to use methanol catalyst and fischer-tropsch catalyst in the synthesis process, but methanol and fischer-tropsch have requirements to the sulfur content and chlorine content in synthetic gas, and total sulfur and total chlorine in synthetic gas need to be removed to below 0.1ppm, and the raw material of synthetic gas contains H2, CO, CO2, CH4, N2, H2O, H2S, COS, NH3, HCN and HCl, therefore, H2S, COS, NH3, HCN and HCl need to be removed before the synthesis of synthetic gas, and one device is used for processing in the prior art, which can easily lead to the standard of desulfurization and dechlorination not reaching below 0.1ppm. UTILITY MODEL CONTENT

[0003] The utility model aims at overcoming the insufficient of prior art, and provides a synthetic gas is with desulfurization and dechlorination system.

[0004] The utility model aims at overcoming the insufficient of prior art, and provides a synthetic gas is with desulfurization and dechlorination system.

[0005] A synthetic gas is with desulfurization and dechlorination system, including caustic washing tower, adsorption tower, heater, hydrogenation reactor and desulfurization reactor, the upper end of caustic washing tower with the lower end of adsorption tower intercommunication, the upper end of adsorption tower with the upper end of hydrogenation reactor intercommunication, the lower end of hydrogenation reactor with the upper end of desulfurization reactor intercommunication, and the adsorption tower with the hydrogenation reactor are sealedly connected with the heater.

[0006] Further, the lower end of caustic washing tower with the output end of inlet pipe intercommunication, caustic washing tower is communicated with adsorption tower through first gas pipe, adsorption tower is communicated with hydrogenation reactor through second gas pipe, hydrogenation reactor is communicated with desulfurization reactor through third gas pipe, and the lower end of desulfurization reactor is sealedly connected with synthetic gas discharge pipe, the heater is sealedly connected on the second gas pipe, the upper end of caustic washing tower is sealedly connected with lye delivery pipe, the lower end of caustic washing tower is sealedly connected with salt waste water discharge pipe, and the first valve is sealedly arranged on the salt waste water discharge pipe.

[0007] Further, the upper end of caustic washing tower is communicated with one end of circulating pipe, the other end of circulating pipe is sealedly connected on the salt waste water discharge pipe and is between the first valve and caustic washing tower, and the circulating pump is sealedly connected on the circulating pipe.

[0008] Further, the output end of lye delivery pipe is communicated with the circulating pipe.

[0009] Further, a first water cooler is arranged on the circulation pipe, and the first water cooler is arranged between the caustic washing tower and the circulation pump.

[0010] Further, a regenerated gas pipe is connected to the second gas pipe in a sealed manner, and a second valve is connected to the regenerated gas pipe in a sealed manner.

[0011] Further, a waste gas pipe is connected to the first gas pipe in a sealed manner, and a fourth valve is arranged on the waste gas pipe in a sealed manner.

[0012] Further, the temperature of the heater is controlled at 150-200 DEG C.

[0013] Further, a second water cooler is connected to the synthetic gas discharge pipe in a sealed manner.

[0014] Further, at least two adsorption towers are connected in parallel between the first gas pipe and the second gas pipe.

[0015] The present application has the following advantages:

[0016] 1) In the present application, H2S, COS, NH3, HCN and HCl in the synthetic gas can be effectively removed by the cooperation of the caustic washing tower, the adsorption tower, the hydrogenation reactor and the desulfurization reactor, and the content of H2S, COS, NH3, HCN and HCl is below 0.1 ppm, and continuous production is realized in the desulfurization and dechlorination process.

[0017] 2) In the present application, HCl gas can be more efficiently removed by the cooperation of the circulation pipe and the circulation pump. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Fig. 1 is a schematic view of the connection structure of the desulfurization and dechlorination system;

[0019] In the figure, 1 is a caustic washing tower, 2 is an adsorption tower, 3 is a heater, 4 is a hydrogenation reactor, 5 is a desulfurization reactor, 6 is an air inlet pipe, 7 is a first gas pipe, 8 is a second gas pipe, 9 is a third gas pipe, 10 is a synthetic gas discharge pipe, 11 is a caustic solution conveying pipe, 12 is a salt wastewater discharge pipe, 13 is a first valve, 14 is a circulation pipe, 15 is a circulation pump, 16 is a first water cooler, 17 is a regenerated gas pipe, 18 is a second valve, 19 is a third valve, 20 is a waste gas pipe, 21 is a fourth valve, 22 is a fifth valve, and 23 is a second water cooler. DETAILED DESCRIPTION

[0020] The technical scheme of the utility model will be described clearly and completely in connection with the embodiments. Obviously, the described embodiments are only some of the embodiments of the utility model, not all. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

[0021] With reference to Figure 1 The utility model provides a technical scheme:

[0022] The application discloses a desulfurization and dechlorination system for synthesis gas, which comprises an alkali washing tower 1, an adsorption tower 2, a heater 3, a hydrogenation reactor 4 and a desulfurization reactor 5, the upper end of the alkali washing tower 1 is communicated with the lower end of the adsorption tower 2, the upper end of the adsorption tower 2 is communicated with the upper end of the hydrogenation reactor 4, the lower end of the hydrogenation reactor 4 is communicated with the upper end of the desulfurization reactor 5, and the heater 3 is sealingly connected between the adsorption tower 2 and the hydrogenation reactor 4. The lower end of the alkali washing tower 1 is communicated with the output end of a gas inlet pipe 6, the alkali washing tower 1 is communicated with the adsorption tower 2 through a first gas conveying pipe 7, the adsorption tower 2 is communicated with the hydrogenation reactor 4 through a second gas conveying pipe 8, the hydrogenation reactor 4 is communicated with the desulfurization reactor 5 through a third gas conveying pipe 9, the lower end of the desulfurization reactor 5 is sealingly connected with a synthesis gas discharging pipe 10, the heater 3 is sealingly connected on the second gas conveying pipe 8, the upper end of the alkali washing tower 1 is sealingly connected with a lye conveying pipe 11, the lower end of the alkali washing tower 1 is sealingly connected with a salt waste water discharging pipe 12, and the salt waste water discharging pipe 12 is sealingly provided with a first valve 13. At least two adsorption towers 2 are connected in parallel between the first gas conveying pipe 7 and the second gas conveying pipe 8. The temperature of the heater 3 is controlled to be 150-200 DEG C. The alkali washing tower 1, the adsorption tower 2, the heater 3, the hydrogenation reactor 4, the first valve 13 and the desulfurization reactor 5 are all prior art devices. The lye conveying pipe 11 inputs 30% sodium hydroxide solution, and the 30% sodium hydroxide solution removes high-content HCl in the alkali washing tower 1. The generated salt waste water can be discharged from the salt waste water discharging pipe 12, the adsorption tower 2 is used for removing water, H2S, COS, NH3, HCN and trace HCl after alkali washing and other impurities, the adsorption tower 2 is a TSA adsorption tower and is provided with at least two, one adsorption tower 2 is used for adsorption while the other adsorption tower 2 is used for regeneration, the regeneration gas pipe 17 is used for inputting regeneration gas during regeneration, the regeneration gas is subsequent decarburization desorption gas or hot nitrogen gas in the prior art, and the two adsorption towers 2 work alternately. The hydrogenation reactor 4 is used for removing COS gas in the synthesis gas, the COS gas is easy to cause poisoning to a subsequent methanol synthesis catalyst, the previous TSA adsorption tower has only a part of COS gas removal effect, and therefore it is necessary to use a hydrolysis catalyst to convert the COS gas. The raw material gas is heated to 150-200 DEG C (water vapor heating or electric heater) by the heater 3, enters the hydrogenation reactor, the hydrogenation reactor is provided with a deep hydrolysis catalyst for the COS gas, the COS is less than 5 ppb, and the chemical reaction formula is COS+H2O→H2S+CO2. Finally, the desulfurization reactor 5 is used for desulfurization treatment, the desulfurization reactor 5 is a zinc oxide fine desulfurization reactor, the chemical reaction generated in the desulfurization reactor 5 is ZnO (solid) +H2S→ZnS (solid) +H2O, and the total sulfur (COS+H2S) content in the synthesis gas discharged from the synthesis gas discharging pipe 10 is less than 10 ppb (0.01 ppm). Through the processing of the desulfurization and dechlorination system, the H2S, COS, NH3, HCN and HCl contents in the synthesis gas are all less than 0.1 ppm, and the deep purification purpose is achieved. In some embodiments, the raw material gas of the synthesis gas is shown in Table 1, and the product gas of the synthesis gas is shown in Table 2.

[0023] Feed gas parameters as shown in Table 1

[0024]

[0025]

[0026] Product gas parameters as shown in Table 2

[0027]

[0028] In some embodiments, the upper end of the caustic washing tower 1 is communicated with one end of the circulating pipe 14, the other end of the circulating pipe 14 is sealingly connected on the salt wastewater discharge pipe 12 and is between the first valve 13 and the caustic washing tower 1, and the circulating pump 15 is sealingly connected on the circulating pipe 14. The output end of the caustic solution delivery pipe 11 is communicated with the circulating pipe 14. Among them, in order to ensure that the removal efficiency of HCl is more than 98%, the circulating absorption is carried out in the caustic washing tower 1 by using the circulating pipe 14 and the circulating pump 15 in the prior art, so that the HCl gas can be better removed and the removal effect of the HCl gas is ensured.

[0029] In some embodiments, the first water cooler 16 is sealingly arranged on the circulating pipe 14 and is arranged between the caustic washing tower 1 and the circulating pump 15. Among them, in the caustic washing tower 1, the 30% sodium hydroxide solution and HCl will have an acid-base neutralization reaction, so a large amount of heat will be generated in the caustic washing tower 1. In order to reduce the temperature in the caustic washing tower 1, the first water cooler 16 in the prior art is arranged to cool, and the temperature in the caustic washing tower 1 is controlled to be within 40°C.

[0030] In some embodiments, the second gas pipe 8 is sealed with a regeneration gas pipe 17, the regeneration gas pipe 17 is sealed with a second valve 18, the second gas pipe 8 is sealed with a third valve 19, and the third valve 19 is arranged between the regeneration gas pipe 17 and the heater 3. The first gas pipe 7 is sealed with a waste gas pipe 20, the waste gas pipe 20 is sealed with a fourth valve 21, the first gas pipe 7 is sealed with a fifth valve 22, and the fifth valve 22 is arranged between the waste gas pipe 20 and the caustic washing tower 1. The adsorption tower 2 is a TSA adsorption tower, so that the adsorption efficiency of H2S, COS, NH3, HCN and a small amount of HCl after caustic washing is reduced after a period of adsorption, so that the adsorption tower 2 needs to be regenerated. The two adsorption towers 2 are connected with the regeneration gas pipe 17, the regeneration gas pipe 17 of the two adsorption towers 2 is controlled by the two second valves 18 respectively, the two adsorption towers 2 are connected with the waste gas pipe 20, and the waste gas pipe 20 of the two adsorption towers 2 is controlled by the two fourth valves 21 respectively. When one of the adsorption towers 2 is regenerated, the second valve 18 and the fourth valve 21 corresponding to the adsorption tower 2 are opened, and the third valve 19 and the fifth valve 22 are closed; the second valve 18 and the fourth valve 21 of the other adsorption tower 2 are closed, and the third valve 19 and the fifth valve 22 are opened for adsorption work. The second valve 18, the third valve 19, the fourth valve 21 and the fifth valve 22 are all valves in the prior art, the waste gas pipe 20 discharges H2S, COS, NH3, HCN and a small amount of HCl after caustic washing, and the regeneration gas pipe 17 introduces hot nitrogen or a mixture of hot H2, CO, CO2, CH4 and N2, or the product gas discharged from the synthesis gas discharge pipe 10.

[0031] In some embodiments, the second water cooler 23 is sealed with the second water cooler 23. The second water cooler 23 is a prior art, and the heater 3 heats the mixer to 150-200 DEG C. In order to cool faster, the second water cooler 23 is used to cool the discharged gas.

[0032] In the description of the present application, it should be understood that the terms "upper", "lower", "bottom", "one end", "top", "middle", "the other end", "coaxial", "one side", "inner", "front", "central", "both ends" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation of the present application.

[0033] In this utility model, unless otherwise explicitly specified and limited, the terms "setting", "installation", "connection", "fixing", "hinged" and other such terms should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0034] The above description is merely a preferred embodiment of this utility model. It should be understood that this utility model is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this utility model should be protected within the scope of the appended claims.

Claims

1. A desulfurization and dechlorination system for syngas, characterized in that: It includes an alkaline washing tower (1), an adsorption tower (2), a hydrogenation reactor (4), and a desulfurization reactor (5). The upper end of the alkaline washing tower (1) is connected to the lower end of the adsorption tower (2), the upper end of the adsorption tower (2) is connected to the upper end of the hydrogenation reactor (4), and the lower end of the hydrogenation reactor (4) is connected to the upper end of the desulfurization reactor (5).

2. The desulfurization and dechlorination system for syngas according to claim 1, characterized in that: The lower end of the alkaline washing tower (1) is connected to the output end of the gas inlet pipe (6). The alkaline washing tower (1) is connected to the adsorption tower (2) through the first gas supply pipe (7). The adsorption tower (2) is connected to the hydrogenation reactor (4) through the second gas supply pipe (8). The hydrogenation reactor (4) is connected to the desulfurization reactor (5) through the third gas supply pipe (9). The lower end of the desulfurization reactor (5) is sealed with a synthesis gas discharge pipe (10). The second gas supply pipe (8) is sealed with a heater (3). The upper end of the alkaline washing tower (1) is sealed with an alkali liquid delivery pipe (11). The lower end of the alkaline washing tower (1) is sealed with a salt wastewater discharge pipe (12).

3. A desulfurization and dechlorination system for syngas according to claim 2, characterized in that: The upper end of the alkaline washing tower (1) is connected to one end of the circulation pipe (14), and the other end of the circulation pipe (14) is sealed and connected to the salt wastewater discharge pipe (12). A circulation pump (15) is sealed and connected to the circulation pipe (14).

4. A desulfurization and dechlorination system for syngas according to claim 3, characterized in that: The output end of the alkali delivery pipe (11) is connected to the circulation pipe (14).

5. A desulfurization and dechlorination system for syngas according to claim 3 or 4, characterized in that: A first water cooler (16) is sealed on the circulation pipe (14), and the first water cooler (16) is located between the alkaline washing tower (1) and the circulation pump (15).

6. A desulfurization and dechlorination system for syngas according to any one of claims 2-4, characterized in that: A regeneration gas pipe (17) is sealed and connected to the second gas supply pipe (8).

7. A desulfurization and dechlorination system for syngas according to any one of claims 2-4, characterized in that: An exhaust pipe (20) is sealed and connected to the first gas supply pipe (7).

8. A desulfurization and dechlorination system for syngas according to any one of claims 2-4, characterized in that: The temperature of the heater (3) is controlled at 150-200℃.

9. A desulfurization and dechlorination system for syngas according to any one of claims 2-4, characterized in that: A second water cooler (23) is sealed and connected to the synthesis gas discharge pipe (10).

10. A desulfurization and dechlorination system for syngas according to any one of claims 2-4, characterized in that: At least two adsorption towers (2) are connected in parallel between the first gas supply pipe (7) and the second gas supply pipe (8).

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