A combined production process of gasification high flash gas and shift stripping gas

Abstract

The application discloses a kind of gasification high flash gas and stripping gas combined production process for producing process, belong to novel coal gasification synthetic ammonia technical field, including saturated hot water tower, high-efficiency separator, stripping tower and spray tower, saturated hot water tower is connected with high-efficiency separator by high flash gas inlet pipe, high-efficiency separator is connected with high flash gas outlet pipe and full solid condensate pipe, full solid condensate pipe is communicated with saturated hot water tower, high flash gas outlet pipe is connected with stripping tower, stripping tower is connected with stripping gas outlet pipe and ammonia water pipe, stripping gas outlet pipe and ammonia water pipe are connected with spray tower, spray tower is connected with non-condensable gas outlet pipe, non-condensable gas outlet pipe is connected with sulfur recovery device.The application uses the above structure of a kind of gasification high flash gas and stripping gas combined production process, removes impurity in high flash gas, reduces the steam consumption in stripping process, energy saving and consumption reduction;Remove gas ammonia in stripping gas, solve the problem of poor quality of sulfuric acid, increase flue gas desulfurization device, improve economic benefit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new coal gasification synthesis ammonia, in particular to a combined production process of gasification high flash gas and shift stripping gas. BACKGROUND

[0002] In the gasification process of the new coal gasification synthesis ammonia, the high flash gas after the flash of the black water of the quenching chamber of the gasifier and the synthesis gas washing tower has a temperature of about 170 DEG C and a water vapor content of about 99%, but because of the serious phenomenon of ash carrying, most enterprises adopt the method of sending the acid gas to the flare for burning treatment, which causes the waste of the heat of the high flash gas.

[0003] In the shift process of the new coal gasification synthesis ammonia, in order to avoid the influence of ammonia in the shift gas on the low-temperature methanol washing, an ammonia washing tower is usually designed to wash and remove the small amount of ammonia in the shift gas. At this time, the shift condensate at the bottom of the ammonia washing tower has a high ammonia content, and in order to realize the further recycling of the water condensate, the condensate is usually subjected to a stripping process. That is, the condensate is introduced into a stripping tower, and 0.5 MPa saturated steam is used for stripping, the ammonia-containing non-condensable gas at the top is sent to the sulfur recovery treatment, and the low-temperature condensate at the bottom is sent to the gasification for recycling, while a low-concentration ammonia water with a concentration of about 2.8% is by-produced. However, because of the high ammonia content in the non-condensable gas, the sulfuric acid product quality is affected when the non-condensable gas is sent to the sulfur recovery section, and if the non-condensable gas is directly sent to the acid gas flare for burning, the flare tail phenomenon is easy to occur; at the same time, the 2.8% ammonia water by-produced is difficult to sell because of the low concentration, which causes the waste of resources. SUMMARY

[0004] The purpose of the present application is to provide a combined production process of gasification high flash gas and shift stripping gas, which removes the coal ash and other impurities in the high flash gas, separates the high flash gas, sends the separated high flash gas to the shift stripping tower, recovers heat, reduces the steam consumption in the stripping process, saves energy and reduces consumption, removes the ammonia in the stripping gas, solves the problems of poor sulfuric acid product quality and flare tail phenomenon caused by the ammonia in the non-condensable gas, increases the flue gas desulfurization device, increases the ammonium sulfate production, and improves the economic benefits.

[0005] In order to achieve the above object, the present application provides a kind of gasification high flash gas and conversion stripping gas combined production process, including saturated hot water tower, high-efficiency separator, conversion stripping tower and spray tower, the saturated hot water tower is connected with the inlet end of the high-efficiency separator by high flash gas inlet pipe, the outlet end of the high-efficiency separator is connected with high flash gas outlet pipe and full solid condensate pipe, the other end of the full solid condensate pipe is communicated with the saturated hot water tower, the other end of the high flash gas outlet pipe is connected with the inlet end of the conversion stripping tower, the outlet end of the conversion stripping tower is connected with stripping gas outlet pipe and ammonia water pipe, the other end of the stripping gas outlet pipe and the ammonia water pipe is connected with the inlet end of the spray tower, the outlet end of the spray tower is connected with non-condensable gas outlet pipe, the non-condensable gas outlet pipe is connected with the inlet end of sulfur recovery device, and the outlet end of the sulfur recovery device is connected with circulating pump.

[0006] Preferably, the inlet end of the conversion stripping tower is connected with steam inlet pipe and conversion condensate pipe, the outlet end of the conversion stripping tower is connected with low-temperature condensing pipe, and the inside of the conversion stripping tower is provided with tower internal heat exchanger.

[0007] Preferably, the outlet end of the spray tower is connected with circulating pump inlet pipe, the circulating pump inlet pipe is connected with the circulating pump, the outlet end of the circulating pump is connected with ammonium sulfite solution circulating pipe and ammonium sulfite concentrated solution pipe, the other end of the ammonium sulfite solution circulating pipe is connected with the spray head inside the spray tower, and the other end of the ammonium sulfite concentrated solution pipe is connected with flue gas desulfurization device.

[0008] Preferably, the outlet end of the flue gas desulfurization device is connected with clear liquid recovery pipe, and the clear liquid recovery pipe is connected with the inlet end of the spray tower.

[0009] Preferably, a densimeter is installed on the ammonium sulfite solution circulating pipe.

[0010] Preferably, the outlet end of the sulfur recovery device is connected with sulfuric acid aqueous solution pipe, and the sulfuric acid aqueous solution pipe is connected with the circulating pump inlet pipe.

[0011] Therefore, the present application has the following beneficial effects:

[0012] (1) The high-efficiency separator is communicated with the outlet end of the saturated hot water tower, to remove impurities such as coal ash in the high flash gas, and the separated high flash gas is sent to the conversion stripping tower to replace part of the stripping steam for heat recovery.

[0013] (2) A spray tower is connected with the gas phase outlet pipeline of the conversion stripping tower, and weak sulfuric acid aqueous solution is used for spray washing, and at the same time, ammonia water by-product of the conversion stripping tower is introduced into the tower, and ammonium sulfite solution generated by reaction is sent to flue gas desulfurization device, and gas phase is sent to sulfur recovery, to completely solve the environmental risk caused by acid flare tailing problem.

[0014] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of an embodiment of the combined production process of gasified high flash gas and shift stripping gas according to the present invention;

[0016] Figure label:

[0017] 1. Saturated hot water tower; 2. High flash gas inlet pipe; 3. High-efficiency separator; 4. High flash gas outlet pipe; 5. Solid condensate pipe; 6. Shift stripping tower; 7. Shift condensate pipe; 8. Steam inlet pipe; 9. Stripping gas outlet pipe; 10. Spray tower; 11. Non-condensable gas outlet pipe; 12. Sulfur recovery unit; 13. Ammonium sulfite solution circulation pipe; 14. Ammonium sulfite concentrate pipe; 15. Flue gas desulfurization unit; 16. Clear liquid recovery pipe; 17. Circulation pump; 18. Ammonia water pipe; 19. Sprayer; 20. Sulfuric acid aqueous solution pipe; 21. Circulation pump inlet pipe; 22. Low-temperature condensate pipe; 23. In-tower heat exchanger; 24. Density meter. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0020] Example

[0021] like Figure 1 As shown, the present invention provides a combined production process of gasified high flash gas and shift stripping gas, including a saturated hot water tower 1, a high-efficiency separator 3, a shift stripping tower 6 and a spray tower 10.

[0022] The saturated hot water tower 1 is connected to the inlet of the high-efficiency separator 3 via a high-flash gas inlet pipe 2. The outlet of the high-efficiency separator 3 is connected to a high-flash gas outlet pipe 4 and a solidified liquid pipe 5, with the other end of the solidified liquid pipe 5 connected to the saturated hot water tower 1. The high-flash gas from the top of the saturated hot water tower 1 has a temperature of approximately 170℃ and a water vapor content of approximately 99%. It enters the high-efficiency separator 3 through the high-flash gas inlet pipe 2, where impurities such as coal ash are separated. The separated high-flash gas is then discharged through the high-flash gas outlet pipe 4. Impurities such as coal ash generated during the high-flash gas separation process are discharged back to the saturated hot water tower 1 for recycling through the solidified liquid pipe 5 at the bottom of the high-efficiency separator 3.

[0023] The other end of the high flash gas outlet pipe 4 is connected with the inlet end of the shift stripping tower 6, and the clean high flash gas with a temperature of about 170°C and a water vapor content of about 99% enters the shift stripping tower 6 through the high flash gas outlet pipe 4. The inlet end of the shift stripping tower 6 is also connected with a steam inlet pipe 8 and a shift condensate pipe 7, the shift condensate enters the shift stripping tower 6 through the shift condensate pipe 7, and the saturated steam at 0.5 MPa enters the shift stripping tower 6 through the steam inlet pipe 8. By using the stripping process, the ammonia gas in the shift condensate is diffused into the gas phase through the countercurrent contact of the shift condensate with the saturated steam and the high flash gas, so as to achieve the purpose of purifying the shift condensate; at the same time, the heat of the high flash gas is recovered and utilized, and the use amount of the saturated steam at 0.5 MPa is reduced, thereby saving energy and reducing consumption. The outlet end of the shift stripping tower 6 is connected with a stripping gas outlet pipe 9 and an ammonia water pipe 18, and the shift stripping tower 6 is internally provided with a tower internal heat exchanger 23. After absorbing the ammonia gas in the shift condensate, the saturated steam at 0.5 MPa and the high flash gas become the shift stripping gas, which is discharged through the stripping gas outlet pipe 9 after being cooled by the tower internal heat exchanger 23. In the cooling process, part of the gas phase is condensed into about 2.8% ammonia water, which is discharged through the ammonia water pipe 18. The outlet end of the shift stripping tower 6 is also connected with a low-temperature condensate pipe 22. The shift condensate purified by stripping has a very low ammonia content, which is discharged through the low-temperature condensate pipe 22 and returned to the gasification section for recycling.

[0024] The other end of the stripping gas outlet pipe 9 and the ammonia water pipe 18 are both connected with the inlet end of the spray tower 10. The stripping gas enters the spray tower 10 from the bottom through the stripping gas outlet pipe 9, and the about 2.8% ammonia water produced in the shift stripping tower 6 enters the spray tower 10 through the ammonia water pipe 18. In the spray tower 10, the dilute sulfuric acid reacts with ammonia to generate ammonium sulfite. The outlet end of the spray tower 10 is connected with a non-condensable gas outlet pipe 11, the non-condensable gas outlet pipe 11 is connected with the inlet end of a sulfur recovery device 12, the outlet end of the sulfur recovery device 12 is connected with a sulfuric acid aqueous solution pipe 20, the sulfuric acid aqueous solution pipe 20 is connected with a circulating pump inlet pipe 21, and the trace H2S and other impurities in the non-condensable gas are absorbed to generate sulfuric acid in the sulfur recovery device 12, so that the gas is further purified; the sulfuric acid solution produced in the sulfur recovery device 12 is connected to the circulating pump inlet pipe 21 through the sulfuric acid aqueous solution pipe 20 and used as the absorbent of the spray tower 10.

[0025] The outlet end of the spray tower 10 is connected with a circulating pump inlet pipe 21, the circulating pump inlet pipe 21 is connected with a circulating pump 17, the outlet end of the circulating pump 17 is connected with an ammonium sulfite solution circulating pipe 13 and an ammonium sulfite concentrated solution pipe 14, the other end of the ammonium sulfite solution circulating pipe 13 is connected with a shower head 19 inside the spray tower 10, and the other end of the ammonium sulfite concentrated solution pipe 14 is connected with a flue gas desulfurization device 15. The ammonium sulfite solution enters the circulating pump 17 through the circulating pump inlet pipe 21, is pressurized, and then returns to the spray tower 10 through the ammonium sulfite solution circulating pipe 13 for circulating reaction, so that the density of the ammonium sulfite solution is increased. The ammonium sulfite solution with qualified density is discharged to the flue gas desulfurization device 15 through the ammonium sulfite concentrated solution pipe 14 to produce ammonium sulfate. The non-condensable gas with very low ammonia content enters a sulfur recovery device through a non-condensable gas outlet pipe 11.

[0026] The outlet end of the flue gas desulfurization device 15 is connected with a clear liquid recovery pipe 16, and the clear liquid recovery pipe 16 is connected with the inlet end of the spray tower 10. The concentrated ammonium sulfite solution with qualified density is subjected to oxidation, crystallization and separation in the flue gas desulfurization device 15 to generate ammonium sulfate products, so that the ammonium sulfate yield is increased and the economic benefit is improved; and the clear liquid generated in the crystallization and separation process is returned to the spray tower 10 through the clear liquid recovery pipe 16 for recycling.

[0027] A densimeter is installed on the ammonium sulfite solution circulating pipe 13 to monitor and adjust the density of the ammonium sulfite solution.

[0028] Therefore, the gasification high flash gas and conversion stripping gas combined production process disclosed by the application removes the coal ash and other impurities in the high flash gas, the separated high flash gas is sent to a conversion stripping tower for heat recovery, so that the steam consumption in the stripping process is reduced and energy consumption is saved; the ammonia in the stripping gas is removed, the problems of poor quality of sulfuric acid and torch tailing phenomenon caused by ammonia in the non-condensable gas are solved; and a flue gas desulfurization device is additionally arranged to increase the ammonium sulfate yield and improve the economic benefit.

[0029] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the application rather than limit them, although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the application can still be modified or replaced equivalently, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the application.

Claims

1. A combined production process of gasified high flash gas and shift stripping gas, characterized in that: The system includes a saturated hot water tower, a high-efficiency separator, a shift stripping tower, and a spray tower. The saturated hot water tower is connected to the inlet of the high-efficiency separator via a high flash gas inlet pipe. The outlet of the high-efficiency separator is connected to a high flash gas outlet pipe and a solidified liquid pipe. The other end of the solidified liquid pipe is connected to the saturated hot water tower. The high flash gas at the top of the saturated hot water tower enters the high-efficiency separator through the high flash gas inlet pipe, where impurities entrained in the high flash gas are separated. The separated high flash gas is then discharged through the high flash gas outlet pipe. Impurities generated during the separation of high flash gas are discharged to a saturated hot water tower for recycling through the full solidified liquid pipe at the bottom of the high-efficiency separator. The other end of the high flash gas outlet pipe is connected to the inlet end of the shift stripping tower, and clean high flash gas enters the shift stripping tower through the high flash gas outlet pipe. The inlet end of the shift stripping tower is connected to a steam inlet pipe and a shift condensate pipe. The shift condensate enters the shift stripping tower through the shift condensate pipe, and the saturated steam enters the shift stripping tower through the steam inlet pipe. Utilizing the stripping process, the shift condensate comes into countercurrent contact with the saturated steam and high flash gas, causing the ammonia in the shift condensate to diffuse into the gas phase, thereby purifying the shift condensate. At the same time, the heat of the high flash gas is recovered and utilized, reducing the amount of saturated steam used, thus saving energy and reducing consumption. The outlet end of the shift stripping tower is connected to a low-temperature condenser pipe, and the outlet end of the shift stripping tower is connected to a stripping gas outlet pipe and an ammonia water pipe. An internal heat exchanger is installed inside the shift stripping tower. After saturated steam and high flash gas absorb ammonia in the shift condensate, they become shift stripping gas. After being cooled by the internal heat exchanger, the gas is discharged through the stripping gas outlet pipe. During the cooling process, part of the gas phase condenses into ammonia water, which is discharged through the ammonia water pipe. The shift condensate purified by stripping has an extremely low ammonia content and is discharged through the low-temperature condensate pipe, returning to the gasification section for recycling. The other ends of the stripping gas outlet pipe and the ammonia water pipe are both connected to the inlet end of the spray tower. The stripping gas enters the spray tower from the bottom through the stripping gas outlet pipe, and the ammonia water produced as a by-product in the stripping tower enters the spray tower through the ammonia water pipe. In the spray tower, dilute sulfuric acid reacts with ammonia to generate ammonium sulfite. The outlet of the spray tower is connected to the non-condensable gas outlet pipe, which is connected to the inlet of the sulfur recovery device. The outlet of the sulfur recovery device is connected to a sulfuric acid aqueous solution pipe, which is connected to the inlet of the circulating pump. Impurities in the non-condensable gas are absorbed in the sulfur recovery device to generate sulfuric acid, and the gas is further purified. The sulfuric acid solution produced in the sulfur recovery device is connected to the inlet of the circulating pump through the sulfuric acid aqueous solution pipe and used as the absorbent for the spray tower. The outlet end of the sulfur recovery device is connected to the circulating pump, the outlet end of the spray tower is connected to the inlet pipe of the circulating pump, the inlet pipe of the circulating pump is connected to the circulating pump, the outlet end of the circulating pump is connected to the ammonium sulfite solution circulation pipe and the ammonium sulfite concentrate pipe, the other end of the ammonium sulfite solution circulation pipe is connected to the spray head inside the spray tower, and the other end of the ammonium sulfite concentrate pipe is connected to the flue gas desulfurization device. Ammonium sulfite solution enters the circulating pump through the inlet pipe of the circulating pump. After being pressurized, it returns to the spray tower through the ammonium sulfite solution circulating pipe to increase the density of the ammonium sulfite solution. The ammonium sulfite solution with qualified density is discharged to the flue gas desulfurization unit through the ammonium sulfite concentrate pipe to produce ammonium sulfate. Non-condensable gas with extremely low ammonia content enters the sulfur recovery unit through the non-condensable gas outlet pipe.

2. The combined production process of gasified high flash gas and shift stripping gas according to claim 1, characterized in that: The outlet end of the flue gas desulfurization device is connected to a clear liquid recovery pipe, which is connected to the inlet end of the spray tower.

3. The combined production process of gasified high flash gas and shift stripping gas according to claim 2, characterized in that: A hydrometer is installed on the ammonium sulfite solution circulation tube.

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