Super Claus combined ammonia process desulfurization device

Abstract

The utility model discloses a super Claus combined ammonia process desulfurization device which comprises a super Claus unit, a tail gas incineration unit and an ammonia washing unit, the super Claus unit comprises a first-stage sulfur cooler, a first-stage preheater, a first-stage reactor, a second-stage sulfur cooler, a second-stage preheater, a second-stage reactor, a third-stage sulfur cooler, a third-stage preheater, a super Claus reactor and a fourth-stage sulfur cooler which are connected in sequence; the tail gas incineration unit comprises an incinerator and a waste heat boiler; the ammonia washing unit comprises an ammonia washing tower; a flue gas outlet of the fourth-stage sulfur cooler is connected with a first flue gas inlet of the incinerator, a flue gas outlet of the incinerator is connected with a flue gas inlet of the waste heat boiler, and a flue gas outlet of the waste heat boiler is connected with an inlet of the ammonia washing tower. According to the method, the sulfur recovery rate is increased, the SO2 concentration of tail gas is reduced, and the acid corrosion problem caused by ammonium sulfate is relieved; the impact force of the flue gas on the tower tray of the ammonia washing tower is reduced, and the safe operation margin of the ammonia washing tower is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of sulfur recovery, in particular to a super Claus combined ammonia desulfurization device. Background Technique

[0002] Sulfur recovery refers to a chemical process of converting sulfides in toxic sulfur-containing gases such as hydrogen sulfide into elemental sulfur, so as to turn waste into treasure and protect the environment. Traditional sulfur recovery devices generally consist of two major units. One is the sulfur production unit, and the mainstream process is to recover elemental sulfur using the conventional Claus process; the other is the tail gas treatment unit, and the mainstream processes are to treat the desulfurized tail gas using processes such as SCOT, Super Claus, RAR, and SSR to achieve compliance emissions at the discharge port. With the improvement of environmental protection requirements, production enterprises generally add a tail gas absorption tower behind the incinerator of traditional sulfur recovery devices. Currently, there are mainly two options for the tail gas absorption tower: an alkali washing tower and an ammonia washing tower.

[0003] CLAUS + tail gas treatment unit + alkali washing (aqueous sodium hydroxide solution) is an early retrofit solution, which has the advantages of small investment, small footprint, and quick results. However, there is a relatively large amount of wastewater in the form of sodium sulfate solution discharged, which requires additional investment for treatment and cannot achieve the goal of nearly zero emissions in the whole process.

[0004] CLAUS + ammonia washing is a new solution used in recent years. The tail gas treatment unit is omitted in the whole process, resulting in significant cost savings and low daily energy consumption. While the tail gas meets the compliance emissions, the discharged ammonium sulfate solution can be recycled and used as a fertilizer raw material through evaporation and crystallization to achieve nearly zero emissions. However, the problems existing in the existing devices are as follows: the concentrations of SO2 and SO3 in the flue gas from the incinerator to the ammonia washing tower are relatively high, which makes on the one hand, the ammonium sulfate solution in the ammonia washing tower unit has strong corrosiveness, and the equipment pipeline corrosion problem is relatively prominent during daily operation; on the other hand, the dew point corrosion risk of the equipment pipelines in the whole flue gas process is high, especially in the waste heat boiler system, and the leakage rate of the bellows compensator part of the flue duct remains high; the flue gas flow rate and temperature from the incinerator to the ammonia washing tower are relatively high, the washing tower has poor anti-fluctuation performance, and the ammonia escape problem at the discharge port and the problem of flue gas tailing caused by aerosols often occur. Summary of the Invention

[0005] To solve the above technical problems, the utility model provides a super Claus combined ammonia desulfurization device.

[0006] The technical solution adopted by the utility model is:

[0007] A super Claus combined ammonia desulfurization device, comprising a super Claus unit, a tail gas incineration unit and an ammonia washing unit. The super Claus unit includes a first-stage sulfur cooler, a first-stage preheater, a first-stage reactor, a second-stage sulfur cooler, a second-stage preheater, a second-stage reactor, a third-stage sulfur cooler, a third-stage preheater, a super Claus reactor and a fourth-stage sulfur cooler connected in sequence; the tail gas incineration unit includes an incinerator and a waste heat boiler; the ammonia washing unit includes an ammonia washing tower; the flue gas outlet of the fourth-stage sulfur cooler is connected to the first flue gas inlet of the incinerator, the flue gas outlet of the incinerator is connected to the flue gas inlet of the waste heat boiler, and the flue gas outlet of the waste heat boiler is connected to the inlet of the ammonia washing tower.

[0008] The super Claus unit uses the combination of CLAUS and Super Claus for desulfurization, improving the sulfur recovery rate of the device; the remaining sulfur-containing waste gas enters the tail gas incineration unit and burns in the incinerator, greatly reducing the concentrations of SO2 and SO3 in the flue gas entering the ammonia washing tower. Since SO3 is the main cause of dew point corrosion, the corrosion problems of the waste heat boiler and expansion joints can be greatly alleviated; finally, the incineration flue gas generates 1.0 MPa steam through the waste heat boiler, and at the same time the temperature of the flue gas entering the ammonia washing tower is greatly reduced. Therefore, the cooling fan can be shut down, thereby reducing the pressure of the flue gas entering the ammonia washing tower and the flue gas flow rate, thus reducing the impact force of the flue gas on the trays of the ammonia washing tower, solving the problem of fluctuating tail gas SO2 concentration, and improving the safe operation of the ammonia washing tower.

[0009] Furthermore, the flue gas outlet of the third-stage preheater is connected to the second flue gas inlet of the incinerator through a reflux pipeline on the one hand, and connected to the flue gas inlet of the super Claus reactor through an acid gas pipeline on the other hand. A reflux valve is provided on the reflux pipeline.

[0010] By adopting the above technical solution, when problems occur in the super Claus unit, the super Claus unit can be cut out online and Claus is temporarily used for desulfurization without the need for overall shutdown.

[0011] Furthermore, an activated acid gas pipeline is connected to the inlet pipeline of the third-stage preheater, a mixer is provided on the outlet pipeline of the third-stage preheater, the first inlet of the mixer is connected to the flue gas outlet of the third-stage preheater through a pipeline, the second inlet of the mixer is connected to the activated air pipeline, and the outlet of the mixer is connected to the flue gas inlet of the super Claus reactor through a pipeline.

[0012] By adopting the above technical solution, the activated acid gas pipeline is connected to the acid gas network, and the activated air pipeline is connected to the compressed air network. During shutdown, the activated acid gas is closed and compressed air is introduced to activate cobalt sulfide catalyst into cobalt oxide to protect the catalyst during shutdown and prevent cobalt sulfide from spontaneous combustion. During startup, the activated acid gas is introduced and the compressed air is closed to sulfide cobalt oxide into cobalt sulfide to restore the activity of the catalyst again.

[0013] Furthermore, a nitrogen pipeline is connected to the activation air pipeline.

[0014] By adopting the above technical solution, the activation temperature of the reactor can be adjusted by nitrogen to prevent overheating during the activation process of the reactor.

[0015] Furthermore, the outlets of the first-stage sulfur cooler, the second-stage sulfur cooler, the third-stage sulfur cooler, and the fourth-stage sulfur cooler are all connected to the liquid sulfur pool through pipelines; an exhaust port is provided at the top of the liquid sulfur pool, the exhaust port is connected to a centrifugal fan, and the outlet of the centrifugal fan is connected to the third flue gas inlet of the incinerator through an exhaust pipeline; an electric tracing pipeline is provided on the exhaust pipeline.

[0016] By adopting the above technical solution, the moisture content of the process gas can be reduced, and the horizontal balance pressure of the ammonia scrubber can be alleviated.

[0017] Furthermore, the ammonia scrubbing unit further includes a concentration section pump, a circulation tank, an absorption section pump, a circulation water tank, and a water washing section pump. The ammonia scrubber is divided into a concentration section, an absorption section, and a water washing section from bottom to top. The inlet of the concentration section pump is communicated with the outlet of the concentration section, the outlet of the concentration section pump is communicated with the inlet of the concentration section, the inlet of the circulation tank is communicated with the outlet of the absorption section, the outlet of the circulation tank is communicated with the inlet of the absorption section pump, and the outlet of the absorption section pump is communicated with the inlet of the absorption section; the outlet of the water washing section is communicated with the inlet of the circulation water tank, the outlet of the circulation water tank is communicated with the inlet of the absorption section pump, and the outlet of the absorption section pump is communicated with the inlet of the water washing section.

[0018] By adopting the above technical solution, the washing effect of the ammonia scrubbing unit can be improved, and the ammonia escape and aerosol phenomenon at the discharge port of the ammonia scrubber can be reduced.

[0019] The beneficial effects of the present utility model: The present invention improves the sulfur recovery rate through Super Claus. On this basis, the tail gas absorption stability of the subsequent system is further improved, the leakage rate of equipment and pipelines is reduced, and the loss of unplanned shutdown is avoided, which has important economic and social benefits. Description of the Drawings

[0020] Figure 1 It is a structural diagram of a Super Claus combined ammonia method desulfurization device of the present application. Detailed Embodiments

[0021] To make the purpose, technical solutions, and advantages of the present utility model clearer, the technical solutions of the present utility model will be clearly and completely described below in conjunction with the drawings and a preferred embodiment.

[0022] Refer to Figure 1A Super Claus combined ammonia desulfurization device includes a Super Claus unit, a tail gas incineration unit and an ammonia washing unit. The Super Claus unit is used to recover sulfur from the original flue gas containing H2S, the tail gas incineration unit is used to incinerate the flue gas containing H2S discharged from the Super Claus unit and recover the heat in the flue gas, and the ammonia washing unit is used to remove SO2 and SO3 from the flue gas discharged from the tail gas incineration unit.

[0023] The super Claus unit includes a primary sulfur cooler 4, a primary preheater 5, a primary reactor 6, a secondary sulfur cooler 7, a secondary preheater 8, a secondary reactor 9, a tertiary sulfur cooler 10, a tertiary preheater 12, a mixer 13, a super Claus reactor 15 and a quaternary sulfur cooler 16 which are sequentially connected through pipelines; the inlet of the primary sulfur cooler 4 is connected to the flue gas outlet of the thermal reaction furnace 3 through a pipeline. The inlet of the thermal reaction furnace 3 is connected to the acid gas pipeline 1 and the combustion air pipeline 2.

[0024] The flue gas outlet of the tertiary preheater 12 is connected to the incinerator 17 through a reflux pipe on one hand, and is connected to the flue gas inlet of the super Claus reactor 15 through an acid gas pipe on the other hand. A reflux valve 14 is provided on the reflux pipe.

[0025] The outlets of the first-stage sulfur cooler 4, the second-stage sulfur cooler 7, the third-stage sulfur cooler 10 and the fourth-stage sulfur cooler 16 are all connected to the liquid sulfur pool 11 through pipelines; an exhaust port is provided on the top of the liquid sulfur pool 11, and the exhaust port is connected to the centrifugal fan 29, and the outlet of the centrifugal fan 29 is connected to the incinerator through an exhaust pipeline; an electric heating pipeline 28 is provided on the exhaust pipeline. The inlet pipeline of the third-stage preheater 12 is connected to an activated acid gas pipeline 25, and the activated acid gas pipeline is connected to the acid gas pipeline network through a valve; the second inlet of the mixer 13 is connected to the activated air pipeline, and the activated air pipeline is connected to the compressed air pipeline network through a valve. The activated air pipeline 26 is connected to a nitrogen pipeline 27, and the nitrogen pipeline 27 is connected to the nitrogen pipeline network through a valve.

[0026] The primary sulfur cooler 4, the primary preheater 5, the primary reactor 6, the secondary sulfur cooler 7, the secondary preheater 8, the secondary reactor 9, the tertiary sulfur cooler 10, the tertiary preheater 12, and the mixer 13 constitute a Claus unit, and the super Claus reactor 15 and the fourth sulfur cooler 16 constitute a super Claus unit. More sulfur is captured by the super Claus unit, thereby improving the recovery rate of sulfur.

[0027] The tail gas incineration unit includes an incinerator 17 and a waste heat boiler 18. The incinerator 17 and the waste heat boiler 18 can be integrated into one unit; or, the incinerator 17 and the waste heat boiler 18 are respectively constituted as separate devices and connected by pipelines.

[0028] In this embodiment, the incinerator 17 is provided with a first flue gas inlet, a second flue gas inlet, and a third flue gas inlet. The first flue gas inlet of the incinerator 17 is connected to the flue gas outlet of the four-stage sulfur cooler 16 through a pipeline. The flue gas outlet of the incinerator is connected to the flue gas inlet of the waste heat boiler 18. The flue gas outlet of the waste heat boiler 18 is connected to the inlet of the ammonia scrubber 19. The second flue gas inlet of the incinerator 17 is connected to the reflux pipeline of the three-stage preheater 12. The third flue gas inlet of the incinerator 17 is connected to the exhaust pipeline of the centrifugal fan 29.

[0029] The ammonia scrubbing unit includes an ammonia scrubber 19, a concentration section pump 20, a circulation tank 21, an absorption section pump 22, a circulation water tank 23, and a water washing section pump 24. The ammonia scrubber 19 is divided into a concentration section, an absorption section, and a water washing section from bottom to top. In this embodiment, the three sections are integrated in one ammonia scrubber 19. The concentration section pump 20, the circulation tank 21, the absorption section pump 22, the circulation water tank 23, and the water washing section pump 24 are arranged outside the ammonia scrubber 19. The inlet of the concentration section pump is connected to the outlet of the concentration section through a pipeline. The outlet of the concentration section pump is connected to the inlet of the concentration section through a pipeline. The concentration section pump is used for the self-circulation of the solution or slurry in the concentration section of the ammonia scrubber 19. The purpose of the circulation is, firstly, to reduce the flue gas temperature, as the lower the temperature, the better the absorption effect. Secondly, to evaporate water vapor and increase the concentration of the ammonium sulfate solution. The inlet of the circulation tank is connected to the outlet of the absorption section through a pipeline. The outlet of the circulation tank is connected to the inlet of the absorption section pump through a pipeline. The outlet of the absorption section pump is connected to the inlet of the absorption section. The absorption section pump 22 pumps out the solution or slurry in the absorption section, stores it temporarily in the circulation tank 21, and then returns it to the ammonia scrubber 19. The absorption section consists of 5 to 6 layers of spraying. Finally, the solution after spraying and absorbing the flue gas converges in the absorption section and then enters the circulation tank 21, where liquid ammonia injection operation and oxidation operation are mainly carried out inside the circulation tank. The outlet of the water washing section is connected to the inlet of the circulation water tank. The outlet of the circulation water tank is connected to the inlet of the absorption section pump. The outlet of the absorption section pump is connected to the inlet of the water washing section. The absorption section pump 24 is used for pumping out the solution or slurry in the water washing section, storing it temporarily in the circulation water tank 23, and then returning it to the ammonia scrubber 19. The water washing unit is mainly used for washing the ammonium sulfate particles in the discharged flue gas and reducing the generation of aerosols.

[0030] The flue gas entering the ammonia scrubber 19 passes through 2 layers of spraying in the concentration section, is cooled after temperature reduction, and then enters the absorption section, where SO2 and SO3 are removed by the absorption liquid. Then, the flue gas enters the water washing section, and the fine particulate matter in the flue gas is removed by the washing water. Finally, the clean flue gas is discharged through the chimney.

[0031] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements are also within the protection scope of the present invention.

Claims

1. A Super Claus combined ammonia desulfurization device, characterized in that: It includes Super Claus unit, tail gas incineration unit and ammonia washing unit; The super Claus unit comprises a primary sulfur cooler (4), a primary preheater (5), a primary reactor (6), a secondary sulfur cooler (7), a secondary preheater (8), a secondary reactor (9), a tertiary sulfur cooler (10), a tertiary preheater (12), a super Claus reactor (15) and a quaternary sulfur cooler (16) which are connected in sequence; The tail gas incineration unit includes an incinerator (17) and a waste heat boiler (18); The ammonia washing unit includes an ammonia washing tower (19); The flue gas outlet of the fourth-stage sulfur cooler (16) is connected to the first flue gas inlet of the incinerator (17), the flue gas outlet of the incinerator is connected to the flue gas inlet of the waste heat boiler (18), and the flue gas outlet of the waste heat boiler (18) is connected to the inlet of the ammonia scrubber (19).

2. A Super Claus combined ammonia desulfurization device according to claim 1, characterized in that: The flue gas outlet of the tertiary preheater (12) is connected to the second flue gas inlet of the incinerator (17) through a reflux pipe on the one hand, and is connected to the flue gas inlet of the super Claus reactor (15) through an acid gas pipe on the other hand. A reflux valve (14) is provided on the reflux pipe.

3. A Super Claus combined ammonia desulfurization device according to claim 1 or 2, characterized in that: The inlet pipeline of the tertiary preheater (12) is connected to an activated acid gas pipeline (25), and the outlet pipeline of the tertiary preheater (12) is provided with a mixer (13). The first inlet of the mixer (13) is connected to the flue gas outlet of the tertiary preheater (12) through a pipeline, the second inlet of the mixer (13) is connected to the activated air pipeline (26), and the outlet of the mixer (13) is connected to the flue gas inlet of the super Claus reactor (15) through a pipeline.

4. A Super Claus combined ammonia desulfurization device according to claim 2, characterized in that: The activated air pipeline (26) is connected to a nitrogen pipeline (27).

5. The Super Claus combined ammonia desulfurization device according to claim 1, characterized in that: The outlets of the first-stage sulfur cooler (4), the second-stage sulfur cooler (7), the third-stage sulfur cooler (10) and the fourth-stage sulfur cooler (16) are all connected to the liquid sulfur pool (11) through pipelines; an exhaust port is provided at the top of the liquid sulfur pool (11), the exhaust port is connected to a centrifugal fan (29), and the outlet of the centrifugal fan is connected to the third flue gas inlet of the incinerator (17) through an exhaust pipeline; an electric heating pipeline (28) is provided on the exhaust pipeline.

6. The Super Claus combined ammonia desulfurization device according to claim 1, characterized in that: The ammonia washing unit further comprises a concentration section pump (20), a circulation tank (21), an absorption section pump (22), a circulation water tank (23) and a water washing section pump (24). The ammonia washing tower (19) is divided into a concentration section, an absorption section and a water washing section from bottom to top. The inlet of the concentration section pump (20) is connected to the outlet of the concentration section, and the outlet of the concentration section pump (20) is connected to the inlet of the concentration section. The inlet of the circulation tank (21) is connected to the outlet of the absorption section, and the outlet of the circulation tank (21) is connected to the inlet of the absorption section pump (22), and the outlet of the absorption section pump (22) is connected to the inlet of the absorption section. The outlet of the water washing section is connected to the inlet of the circulation water tank (23), and the outlet of the circulation water tank (23) is connected to the inlet of the absorption section pump (22), and the outlet of the absorption section pump (22) is connected to the inlet of the water washing section.

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