A coke oven gas deamination method and system for producing large granular ammonium sulfate

Abstract

This invention relates to a method and system for deammoniation of coke oven gas in the production of large-particle ammonium sulfate. By synergistic action of a gas heating system, an ammonia absorption system, a fine crystal elimination system, a heat control system, and an acidity control system, the water content, solubility, and acidity of the mother liquor are adjusted to control the growth rate of ammonium sulfate crystals, thereby reducing the amount of crystal nuclei generated and thus obtaining large-particle ammonium sulfate products. This invention achieves the goal of producing large-particle ammonium sulfate and increases the economic added value of ammonium sulfate products.

Description

Technical Field

[0001] This invention relates to the field of coke oven gas deammoniation technology, and in particular to a method and system for deammoniation of coke oven gas used in the production of large-particle ammonium sulfate. Background Technology

[0002] During the coking process, some of the nitrogen in the coal is converted into ammonia and enters the coke oven gas system. Typically, the ammonia content in raw coal gas is 6–9 g / m³. 3 Ammonia is a corrosive medium and a valuable chemical raw material, therefore it must be removed from coke oven gas. From the perspective of ammonia resource recovery, it can be used to prepare ammonium sulfate and anhydrous ammonia products. In particular, the absorption of ammonia from coke oven gas using sulfuric acid has a strong absorption driving force and no reversible reaction, resulting in the lowest ammonia content in the purified gas compared to other processes. Furthermore, ammonium sulfate is a solid product, easy to store and transport, suitable for continuous and large-scale production, and especially suitable for the removal of ammonia from coke oven gas.

[0003] The production of ammonium sulfate from ammonia in coke oven gas involves an absorption and crystallization process. The quality of the absorption process determines the ammonia content in the purified gas, while the quality of the crystallization process directly determines the quality of the ammonium sulfate product. Ammonium sulfate crystallization mainly consists of several stages: the formation of a supersaturated solution, the generation of crystal nuclei, and crystal growth. The ammonium sulfate slurry forms a supersaturated solution, and after reaching a certain degree of supersaturation, solid microcrystalline grains precipitate—this is the crystal nucleus formation process, also known as primary nucleation. Next comes the growth of these nuclei, also known as crystal growth. Simultaneously, due to the flow of the liquid, friction and collisions between crystals and between crystals and equipment, as well as the scouring of the crystal surface by the liquid, new crystal nuclei are generated—this is called secondary nucleation. Usually, the formation of crystal nuclei and the growth of crystals occur simultaneously. During the crystallization process, both the formation and growth of crystal nuclei consume solute in the solution; that is, a certain degree of supersaturation acts as the driving force. Each crystal grows from a single crystal nucleus. Under certain conditions, the higher the nucleation rate and the more nuclei are generated, the slower the growth rate becomes due to the limited solute in the solution simultaneously supplying a large number of nuclei. This results in a large number of fine crystals. Conversely, fewer nuclei are generated, leading to larger crystal grains. Therefore, to obtain large-particle ammonium sulfate products, it is necessary to control the formation processes of primary and secondary nucleation to avoid the formation of too many nuclei. Common process methods include reducing impurities in the system (such as dust and ions) and adjusting the supersaturation of the mother liquor (controlling temperature and acidity).

[0004] Reducing impurities (such as dust and ions) within the system can be achieved by optimizing the operation of upstream units. However, adjusting supersaturation requires consideration of multiple factors such as temperature and acidity, making it relatively complex. Chinese patent application CN114772611A discloses a "Production System and Method for Ammonium Sulfate from Amino Acid Gas," which uses heated compressed air to stir the mother liquor, reducing power consumption, preventing mother liquor leakage, and addressing scaling issues in the spraying device. It also facilitates the formation of a concentration gradient to some extent. However, since this process only applies to non-coal gas systems, it is not suitable for producing ammonium sulfate using coke oven gas. Chinese utility model patent CN216837850U ​​discloses a "Coke Oven Gas Ammonia Removal System," including a gas preheater, a spray-type saturator, a cyclone eliminator, and a mother liquor circulation pump. Due to the system's simplicity, it cannot control key parameters such as the temperature and acidity of the mother liquor, thus compromising the quality of the resulting ammonium sulfate product. Chinese utility model patent CN216571638U discloses a "control system for coking ammonium sulfate production". It is equipped with a full-flow tank regulating valve in the pipeline connecting the liquid level balancing pump and the full-flow tank, and an acid addition regulating valve in the pipeline connecting the sulfuric acid high-level tank and the full-flow tank. By continuously detecting the acidity of the mother liquor, the acid addition amount is automatically adjusted, avoiding the shortcomings of manual detection. Although it promotes the development of automation in ammonium sulfate system production, it still cannot control the quality of the mother liquor. Summary of the Invention

[0005] This invention provides a method and system for deammoniation of coke oven gas in the production of large-particle ammonium sulfate. Through the synergistic effect of a gas heating system, an ammonia absorption system, a fine crystal removal system, a heat control system, and an acidity control system, the purpose of producing large-particle ammonium sulfate is achieved, thereby increasing the economic added value of ammonium sulfate products.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] A method for deammoniation of coke oven gas in the production of large-particle ammonium sulfate involves controlling the growth rate of ammonium sulfate crystals by synergistically adjusting the water content, solubility, and acidity of the mother liquor, thereby reducing the amount of crystal nuclei formed and ultimately obtaining large-particle ammonium sulfate products. The specific process includes the following steps:

[0008] 1) When the inlet gas temperature is below 40℃, turn on the gas heating system to heat the gas to 40-65℃, and control the water content in the ammonium sulfate mother liquor by controlling the gas temperature; this step is omitted when the outlet gas temperature is above 65℃.

[0009] 2) The heated coal gas enters the ammonia absorption system, where sulfuric acid reacts with the ammonia in the coal gas to produce ammonium sulfate. After the sulfuric acid absorbs the ammonia, the ammonia content in the coal gas is below 30 mg / Nm³. 3 ;

[0010] 3) The ammonium sulfate mother liquor is heated by a mother liquor heating system to form a local overheated zone, thereby controlling the solubility of the ammonium sulfate mother liquor and eliminating fine crystals;

[0011] 4) The acidity of the ammonium sulfate mother liquor is controlled within the range of 2% to 6% by an acidity control system;

[0012] 5) The heat from the gas heating system and the mother liquor heating system is precisely allocated through a heat control system. The heat control system includes an input parameter measurement module, an output parameter measurement module, a heat calculation module, and a heat control module. The input parameter measurement module measures the following variables: the inlet temperature Tin of the gas / ammonium sulfate mother liquor and the inlet flow rate Qin of the gas / ammonium sulfate mother liquor. The output parameter measurement module measures the following variables: the outlet temperature T of the gas / ammonium sulfate mother liquor. out q, the outlet flow rate of coal gas / ammonium sulfate mother liquor out The heat calculation module calculates the input heat Q of the gas heating system / mother liquor heating system based on the measured values ​​returned by the input parameter measurement module and the output parameter measurement module, respectively. in The output heat Q of the gas heating system / mother liquor heating system out And the supplementary heat QD of the gas heating system / mother liquor heating system, the calculation formula is:

[0013] Q in =C in q in T in C in The specific heat of the input coal gas / ammonium sulfate mother liquor;

[0014] Q out =C out q out T out C out The specific heat of the output coal gas / ammonium sulfate mother liquor;

[0015] QD = Q out -Q in .

[0016] Furthermore, the obtained large-particle ammonium sulfate has a particle size range of 400–3000 μm.

[0017] Furthermore, the gas heating system can be heated by steam, electricity, or microwave.

[0018] Furthermore, the process of sulfuric acid absorbing ammonia is carried out in a saturator or an acid washing tower.

[0019] Furthermore, the heating method of the ammonium sulfate mother liquor is steam heating, electric heating, or microwave heating; the mother liquor heating system adopts an intermittent operation mode, and the mother liquor heating system is started when the proportion of fine crystals with a particle size of less than 2 mm reaches 35%; after the mother liquor heating system is started, the mother liquor heating system is turned off when the proportion of fine crystals with a particle size of less than 2 mm is less than 30%.

[0020] Furthermore, when the mother liquor heating system stops operating, the heat control system automatically increases the heat supply of the gas heating system according to a preset value; conversely, when the mother liquor heating system is put into operation, the heat control system automatically reduces the heat supply of the gas heating system.

[0021] Furthermore, the amount of water carried out by the coal gas from the ammonia absorption system = the amount of water carried in by the coal gas + the amount of water carried in by other gases + the amount of water carried in by sulfuric acid + the amount of water carried in by the centrifuge + the amount of water carried in by the tail gas scrubbing tower - the amount of water carried out by ammonium sulfate after the centrifuge.

[0022] Furthermore, the heat supplied by the heat control system to the gas heating system is QDg, and the heat supplied to the mother liquor heating system is QDc; the total supplied heat ΣQ=QDg+QDc, that is, the total supplied heat = heat carried out by the gas + heat carried out by the wet ammonium sulfate + heat carried out by the mother liquor sent to the crystallization tank + heat loss in the saturator / acid washing tower - heat carried in by the gas - heat carried in by other gases - heat carried in by sulfuric acid - heat of sulfuric acid dilution - heat carried in by the washing water - heat carried in the returned mother liquor - heat of ammonium sulfate formation - heat of ammonium sulfate crystallization.

[0023] A coke oven gas ammonia removal system for producing large-particle ammonium sulfate includes an ammonia absorption system, a high-pressure sulfuric acid tank, a full-flow tank, a mother liquor storage tank, a crystallization pump, a large mother liquor circulation pump, and a small mother liquor pump. The gas inlet of the ammonia absorption system is connected to a coke oven gas pipeline via a gas inlet pipe, which is equipped with a gas inlet valve. The gas outlet of the ammonia absorption system is connected to a deammoniation gas pipeline via a gas outlet pipe, which is sequentially equipped with a mist eliminator, a gas outlet valve, and a drain funnel along the gas flow direction. The drain funnel is connected to a gas liquid seal tank. The gas outlet pipe is connected to the gas inlet pipe via a transfer pipe, which is equipped with a transfer valve. The sulfuric acid outlet of the high-pressure sulfuric acid tank is connected to the sulfuric acid inlet of the mother liquor storage tank via a sulfuric acid outlet pipe. The ammonium sulfate mother liquor outlet is connected to the ammonium sulfate mother liquor inlet of the ammonia absorption system via an ammonium sulfate mother liquor pipeline. Small mother liquor pumps and flow regulating valves are sequentially installed along the flow direction of the ammonium sulfate mother liquor on the mother liquor pipeline; the small mother liquor pumps and flow regulating valves are interlocked. The ammonium sulfate outlet of the ammonia absorption system is connected to a full-flow tank via an ammonium sulfate outlet pipeline, and the full-flow tank is connected to a mother liquor storage tank via a full-flow mother liquor pipeline. The ammonia absorption system has a circulating mother liquor outlet connected to the circulating mother liquor inlet of the ammonia absorption system via a circulating mother liquor pipeline, and a large mother liquor circulating pump is installed on the circulating mother liquor pipeline. The crystallizing mother liquor outlet of the ammonia absorption system is connected to a crystallizing mother liquor external delivery pipeline, and a crystallization pump is installed on the crystallizing mother liquor external delivery pipeline. The coke oven gas deammoniation system also includes a gas heating system, a mother liquor heating system, and an acidity control system. The system includes a gas heating system and a heat control system; a gas heating system is located on the gas inlet pipe; an ammonia absorption system has a circulating mother liquor outlet 2, which is connected to the circulating mother liquor pipe upstream of the large mother liquor circulation pump via a heated circulating mother liquor pipe; a mother liquor heating system is installed on the heated circulating mother liquor pipe; an acidity control system includes an acidity measurement module, a sulfuric acid regulating valve, and an observation sight; the acidity measurement module is located in the ammonia absorption system and is used to detect the acidity of the ammonium sulfate mother liquor; a high-pressure sulfuric acid tank has a regulating sulfuric acid outlet, which is connected to the ammonium sulfate outlet pipe and the circulating mother liquor pipe upstream of the large mother liquor circulation pump via a regulating sulfuric acid pipe; a sulfuric acid regulating valve and an observation sight are installed on the regulating sulfuric acid pipe; the acidity measurement module is interlocked with the sulfuric acid regulating valve; both the gas heating system and the mother liquor heating system are... Connected to the corresponding heat control system, the heat control system consists of a heat regulating valve, an input parameter measurement module, an output parameter measurement module, a heat calculation module, and a heat control module. The heat regulating valve is installed on the heat input pipeline of the gas heating system and the heat input pipeline of the mother liquor heating system. The input parameter measurement module is installed on the gas inlet pipeline upstream of the gas heating system and the heating circulation mother liquor pipeline upstream of the mother liquor heating system. The output parameter measurement module is installed on the gas inlet pipeline downstream of the gas heating system and the heating circulation mother liquor pipeline downstream of the mother liquor heating system. The control end of the heat control valve, the input parameter measurement module, the output parameter measurement module, and the heat calculation module are connected to the heat control module.

[0024] Furthermore, the gas heating system is a steam heating system, an electric heating system, or a microwave heating system; the ammonia absorption system is a saturator or an acid washing tower; and the mother liquor heating system is a steam heating system, an electric heating system, or a microwave heating system.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1) By synergistically adjusting the water content, solubility, and acidity of the ammonium sulfate mother liquor, the growth rate of ammonium sulfate crystals is controlled, minimizing the amount of crystal nuclei generated, thereby obtaining large-particle ammonium sulfate crystals;

[0027] 2) The gas heating system, mother liquor heating system, heat control system, and acidity control system are set up to operate in coordination with the ammonia absorption system. The gas heating system is used to heat the gas to be deammoniated, the ammonia absorption system is used to absorb ammonia from the gas, the mother liquor heating system is used to remove fine crystals from the ammonium sulfate mother liquor, the heat control system is used to precisely adjust the heat of the gas heating system and the mother liquor heating system, and the acidity control system is used to control the acidity of the ammonium sulfate mother liquor. The control is precise and highly automated.

[0028] 3) The obtained ammonium sulfate products have a particle size range of 400 to 3000 μm, which meets the requirements for producing large-particle ammonium sulfate products and improves the economic added value of ammonium sulfate products. Attached Figure Description

[0029] Figure 1 This is a process flow diagram (system structural schematic diagram) of the coke oven gas deammoniation method described in this invention.

[0030] In the diagram: 1. Gas inlet valve 2. Gas outlet valve 3. Flow valve 4. Drain funnel 5. Gas liquid seal tank 6. Mist eliminator 7. Ammonia absorption system 8. Gas heating system 9. Mother liquor heating system 10. Heat control system 11. Input parameter measurement module 12. Output parameter measurement module 13. Heat calculation module 14. Heat control module 15. Heat regulating valve 16. Acidity control system 17. Acidity measurement module 18. Sulfuric acid high-pressure tank 19. Sulfuric acid regulating valve 20. Sight glass 21. Large mother liquor circulation pump 22. Crystallization pump 23. Small mother liquor pump 24. Flow regulating valve 25. Full flow tank 26. Mother liquor storage tank 27. Slag box Detailed Implementation

[0031] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0032] like Figure 1As shown, the present invention discloses a method for deammoniation of coke oven gas in the production of large-particle ammonium sulfate. This method controls the growth rate of ammonium sulfate crystals by synergistically adjusting the water content, solubility, and acidity of the mother liquor, thereby reducing the amount of crystal nuclei generated and ultimately obtaining large-particle ammonium sulfate products. Specifically, the method includes the following processes:

[0033] 6) When the inlet gas temperature is below 40℃, turn on the gas heating system 8 to heat the gas to 40-65℃. Control the water content in the ammonium sulfate mother liquor by controlling the gas temperature. This step is omitted when the outlet gas temperature is above 65℃.

[0034] 7) The heated coal gas enters the ammonia absorption system 7, where sulfuric acid reacts with the ammonia in the coal gas to produce ammonium sulfate. After the sulfuric acid absorbs the ammonia, the ammonia content in the coal gas is below 30 mg / Nm³. 3 ;

[0035] 8) The ammonium sulfate mother liquor is heated by the mother liquor heating system 9 to form a local overheating zone, control the solubility of the ammonium sulfate mother liquor, and eliminate fine crystals;

[0036] 9) The acidity of the ammonium sulfate mother liquor is controlled within the range of 2% to 6% by the acidity control system 10;

[0037] 10) The heat from the gas heating system 8 and the mother liquor heating system 9 is precisely allocated through the heat control system 10; the heat control system 10 includes an input parameter measurement module 11, an output parameter measurement module 12, a heat calculation module 13, and a heat control module 14; the variables measured by the input parameter measurement module 11 include: the inlet temperature T of the gas / ammonium sulfate mother liquor. in Inlet flow rate q of coal gas / ammonium sulfate mother liquor in The variables measured by the output parameter measurement module 12 include: the outlet temperature T of the coal gas / ammonium sulfate mother liquor. out q, the outlet flow rate of coal gas / ammonium sulfate mother liquor out The heat calculation module 13 calculates the input heat Q of the gas heating system 8 / mother liquor heating system 9 based on the measured values ​​returned by the input parameter measurement module 11 and the output parameter measurement module 12. in The output heat Q of the gas heating system 8 / mother liquor heating system 9 out The formula for calculating the supplementary heat QD of the gas heating system 8 / mother liquor heating system 9 is as follows:

[0038] Q in =C in q in T in C in The specific heat of the input coal gas / ammonium sulfate mother liquor;

[0039] Q out =C out q out T outC out The specific heat of the output coal gas / ammonium sulfate mother liquor;

[0040] QD = Q out -Q in .

[0041] Furthermore, the obtained large-particle ammonium sulfate has a particle size range of 400–3000 μm.

[0042] Furthermore, the gas heating system 8 is heated by steam, electricity, or microwave.

[0043] Furthermore, the process of sulfuric acid absorbing ammonia is carried out in a saturator or an acid washing tower.

[0044] Furthermore, the heating method of the ammonium sulfate mother liquor is steam heating, electric heating or microwave heating; the mother liquor heating system 9 adopts an intermittent operation mode, and the mother liquor heating system 9 is started when the proportion of fine crystals with a particle size of less than 2 mm reaches 35%; after the mother liquor heating system is started, the mother liquor heating system 9 is turned off when the proportion of fine crystals with a particle size of less than 2 mm is less than 30%.

[0045] Furthermore, when the mother liquor heating system 9 stops operating, the heat control system 10 automatically increases the heat supply of the gas heating system 8 according to a preset value; conversely, when the mother liquor heating system 9 is put into operation, the heat control system 10 automatically reduces the heat supply of the gas heating system 8.

[0046] Furthermore, the amount of water carried out by the coal gas from the ammonia absorption system 7 = the amount of water carried in by the coal gas + the amount of water carried in by other gases + the amount of water carried in by sulfuric acid + the amount of water carried in by the centrifuge + the amount of water carried in by the tail gas scrubbing tower - the amount of water carried out by ammonium sulfate after the centrifuge.

[0047] Furthermore, the heat supplied by the heat control system 10 to the gas heating system 8 is QDg, and the heat supplied to the mother liquor heating system 9 is QDc; the total supplied heat ΣQ=QDg+QDc, that is, the total supplied heat = heat carried out by the gas + heat carried out by the wet ammonium sulfate + heat carried out by the mother liquor sent to the crystallization tank + heat loss in the saturator / acid washing tower - heat carried in by the gas - heat carried in by other gases - heat carried in by sulfuric acid - heat carried in by sulfuric acid dilution - heat carried in by washing water - heat carried in by the returned mother liquor - heat of ammonium sulfate formation - heat of ammonium sulfate crystallization.

[0048] A coke oven gas ammonia removal system for producing large-particle ammonium sulfate includes an ammonia absorption system 7, a high-pressure sulfuric acid tank 18, a full-flow tank 25, a mother liquor storage tank 26, a crystallization pump 22, a large mother liquor circulation pump 21, and a small mother liquor pump 23. The gas inlet of the ammonia absorption system 7 is connected to a coke oven gas pipeline via a gas inlet pipe, and a gas inlet valve 1 is installed on the gas inlet pipe. The gas outlet of the ammonia absorption system 7 is connected to a deammoniation gas pipeline via a gas outlet pipe, and a mist eliminator 6, a gas outlet valve 2, and a liquid discharge funnel 4 are sequentially installed along the gas flow direction on the gas outlet pipe, which is connected to a gas liquid seal tank 5. The gas outlet pipe is connected to the gas inlet pipe via a traffic pipe, and a traffic valve 3 is installed on the traffic pipe. The high-pressure sulfuric acid tank... The sulfuric acid outlet of the 18th cell is connected to the sulfuric acid inlet of the mother liquor storage tank 26 via a sulfuric acid outlet pipeline; the ammonium sulfate mother liquor outlet of the mother liquor storage tank 26 is connected to the ammonium sulfate mother liquor inlet of the ammonia absorption system 7 via an ammonium sulfate mother liquor pipeline, and a small mother liquor pump 23 and a flow regulating valve 24 are sequentially installed along the flow direction of the ammonium sulfate mother liquor on the ammonium sulfate mother liquor pipeline; the small mother liquor pump 23 and the flow regulating valve 24 are interlocked; the ammonium sulfate outlet of the ammonia absorption system 7 is connected to the full flow tank 25 via an ammonium sulfate outlet pipeline, and the full flow tank 25 is connected to the mother liquor storage tank 26 via a full flow mother liquor pipeline; the ammonia absorption system 7 has a circulating mother liquor outlet connected to the circulating mother liquor inlet of the ammonia absorption system 7 via a circulating mother liquor pipeline, and a large mother liquor circulating pump 21 is installed on the circulating mother liquor pipeline; the ammonia absorption system The crystallizing mother liquor outlet of system 7 is connected to a crystallizing mother liquor delivery pipeline, and a crystallization pump 22 is installed on the crystallizing mother liquor delivery pipeline; the coke oven gas deammoniation system also includes a gas heating system 8, a mother liquor heating system 9, an acidity control system 16, and a heat control system 10; the gas heating system 8 is installed on the gas inlet pipeline; the ammonia absorption system 7 has a circulating mother liquor outlet 2 connected to the circulating mother liquor pipeline upstream of the large mother liquor circulating pump 21 through a heated circulating mother liquor pipeline; the heated circulating mother liquor pipeline is equipped with the mother liquor heating system 9; the acidity control system 16 includes an acidity measurement module 17, a sulfuric acid regulating valve 19, and an observation mirror 20; the acidity measurement module 17 is installed in the ammonia absorption system 7 and is used to detect the acidity of the ammonium sulfate mother liquor; The high-level sulfuric acid tank 18 is equipped with a regulating sulfuric acid outlet, which is connected to the ammonium sulfate outlet pipe and the circulating mother liquor pipe upstream of the large mother liquor circulation pump 21 via a regulating sulfuric acid pipe. A sulfuric acid regulating valve 19 and an observation sight 20 are installed on the regulating sulfuric acid pipe. The acidity measurement module 17 is interlocked with the sulfuric acid regulating valve 19. The gas heating system 8 and the mother liquor heating system 9 are both connected to the corresponding heat control system 10. The heat control system 10 consists of a heat regulating valve 15, an input parameter measurement module 11, an output parameter measurement module 12, a heat calculation module 13, and a heat control module 14. The heat regulating valve 15 is installed on the heat input pipe of the gas heating system 8 and the heat input pipe of the mother liquor heating system 9.Input parameter measurement modules 11 are respectively installed on the gas inlet pipe upstream of the gas heating system 8 and the heating circulation mother liquor pipe upstream of the mother liquor heating system 9; output parameter measurement modules 12 are respectively installed on the gas inlet pipe downstream of the gas heating system 8 and the heating circulation mother liquor pipe downstream of the mother liquor heating system 9; the control terminal of the heat control valve 15, the input parameter measurement modules 11, the output parameter measurement modules 12, and the heat calculation module 13 are respectively connected to the heat control module 14.

[0049] Furthermore, the gas heating system 8 is a steam heating system, an electric heating system, or a microwave heating system; the ammonia absorption system 7 is a saturator or an acid washing tower; and the mother liquor heating system 9 is a steam heating system, an electric heating system, or a microwave heating system.

[0050] The coke oven gas deammoniation system for producing large-particle ammonium sulfate according to the present invention consists of a gas heating system, an ammonia absorption system, a mother liquor heating system, a heat control system, and an acidity control system. The purpose of producing large-particle ammonium sulfate is achieved through the coordinated operation of the above five systems.

[0051] 1. Gas heating system;

[0052] Coke oven gas (hereinafter referred to as gas) is heated to 40-65°C using steam, electricity, or microwave. The property of heated gas to carry more water vapor is utilized to control the water content in ammonium sulfate mother liquor. To ensure the normal operation of the deammoniation process, the coke oven gas deammoniation system described in this invention needs to operate continuously. In the initial stage of operation, when the inlet gas temperature is below 40°C, the gas heating system needs to be turned on; when the outlet gas temperature is above 65°C, the gas heating system is interlocked and shut down.

[0053] 2. Ammonia absorption system;

[0054] The ammonia in coal gas is absorbed by the chemical reaction between sulfuric acid and ammonia, thus achieving the purpose of ammonia removal from the coal gas. After absorption, the ammonia content in the coal gas is below 30 mg / Nm³. 3 ;

[0055] 3. Mother liquor heating system;

[0056] Heating the circulating mother liquor using steam, electricity, or microwaves creates localized overheating zones that control the solubility of the ammonium sulfate mother liquor. This helps eliminate fine crystals and reduce the crystal aspect ratio, resulting in better crystal morphology. The mother liquor heating system can be operated continuously or intermittently depending on the proportion of fine crystals in the ammonium sulfate mother liquor. When there are many fine crystals in the ammonium sulfate mother liquor (≥35% of which are 2mm in size), the mother liquor heating system is activated; it can be shut down after the fine crystals are eliminated (<30% of which are 2mm in size).

[0057] 4. Heat control system;

[0058] It is used to precisely allocate heat between the gas heating system and the mother liquor heating system, which helps to control and distribute heat between the two systems. When the mother liquor heating system is running, the heat supply to the gas heating system needs to be reduced accordingly.

[0059] 5. Acidity control system;

[0060] Used to control the acidity of ammonium sulfate mother liquor, so that the acidity of ammonium sulfate mother liquor in the ammonia absorption system is maintained within the normal range of 2% to 6%.

[0061] The working principle and control process of the coke oven gas deammoniation method for producing large-particle ammonium sulfate described in this invention are as follows:

[0062] The coal gas to be deammonerated from the external unit is first heated to 40–65°C by the gas heating system. Heating can be achieved using steam, electricity, or microwave. The gas heating system mainly consists of a gas preheater and associated valves, pipelines, and instruments. The added heat (QDg) can be adjusted through the heat control system. During initial operation, if the gas temperature is below 40°C, the gas heating system must be forcibly activated. If the gas temperature exceeds 65°C, the gas heating system should be interlocked and shut down.

[0063] The heated coal gas enters the ammonia absorption system, where, in the saturator or acid washing tower, sulfuric acid reacts with the ammonia in the coal gas to produce ammonium sulfate. The chemical equation is as follows:

[0064] 2NH3 + H2SO4 → (NH4)2SO4

[0065] After the ammonia in the coal gas is absorbed, the ammonia content can be reduced to 30 mg / Nm³. 3 To prevent downstream equipment and pipelines from being corroded by entrained acidic droplets, a mist eliminator is also installed on the outlet gas pipeline of the ammonia absorption system.

[0066] The amount of water carried away by the gas from the ammonia absorption system is calculated using the following formula:

[0067] Water carried out by coal gas = Water carried in by coal gas + Water carried in by other gases + Water carried in by sulfuric acid + Water carried in by centrifuge + Water carried in by tail gas scrubbing tower - Water carried out by ammonium sulfate after centrifuge

[0068] To ensure the continuous progress of the absorption reaction, a mother liquor containing crystals is continuously sprayed into the ammonia absorption system by a large mother liquor circulation pump. A mother liquor heating system is also installed on the upstream pipeline at the suction end of the large mother liquor circulation pump. This system utilizes steam, electricity, or microwaves to generate localized high temperatures, increasing the solubility of the passing ammonium sulfate mother liquor. This helps eliminate fine crystals, reduce the aspect ratio of the crystals, and improve the quality of the ammonium sulfate product.

[0069] The mother liquor heating system can operate intermittently based on the proportion of fine crystals in the ammonium sulfate mother liquor. Specifically, the system is activated when the proportion of fine crystals (below 2mm) reaches 35% and shut off when this proportion drops to 30%. The mother liquor heating system mainly consists of a tubular mother liquor heater and associated valves, pipelines, and instruments. The added heat (QDc) can be adjusted through the heat control system.

[0070] To ensure the heat balance of the entire coke oven gas deammoniation system, this invention sets up a heat control system for allocating heat between the two heating systems. The heat control system includes an input parameter measurement module, an output parameter measurement module, a heat calculation module, and a heat control module. Its operating principle is as follows:

[0071] First, the inlet temperature T of the coal gas / ammonium sulfate mother liquor is measured by the input parameter measurement module. in and inbound traffic q in (When there is no flow meter on site, q) in (Based on the flow rate of the fluid conveying equipment); then, the outlet temperature T of the coal gas / ammonium sulfate mother liquor is measured by the output parameter measurement module. out and export flow q out (When there is no flow meter on site, q) out (Based on the flow rate of the fluid conveying equipment); then, the above parameters are sent to the heat calculation module and calculated according to the following formula:

[0072] The input heat Q of the gas heating system / mother liquor heating system in =C in q in T in ;

[0073] The output heat Q of the gas heating system / mother liquor heating system out =C out q out T out ;

[0074] In the above formula, C in To determine the specific heat of the input coal gas / ammonium sulfate mother liquor, C out The specific heat of the output coal gas / ammonium sulfate mother liquor.

[0075] The supplemental heat for the gas heating system / mother liquor heating system is QD = Q out -Q in

[0076] In this invention, since both the gas heating system and the mother liquor heating system require additional heat (QDg and QDc), the sum of the two is the total additional heat.

[0077] ΣQ=QDg+QDc=Heat carried out by coal gas + Heat carried out by wet ammonium sulfate + Heat carried out by mother liquor sent to crystallization tank + Heat loss from saturator - Heat carried in by coal gas - Heat carried in by other gases - Heat carried in by sulfuric acid - Heat of sulfuric acid dilution - Heat carried in by washing water - Heat carried in returned mother liquor - Heat of ammonium sulfate formation - Heat of ammonium sulfate crystallization

[0078] However, because the mother liquor heating system operates intermittently, when it shuts down, the heat control system will automatically increase the heat supply to the gas heating system according to a preset value. Conversely, when the mother liquor heating system is operational, the heat control system will automatically decrease the heat supply to the gas heating system. In short, the heat control system is the guarantee for maintaining the heat balance of the entire system.

[0079] 6. Acidity control system;

[0080] It mainly consists of an acidity measurement module, a high-level sulfuric acid tank, a sulfuric acid regulating valve, a sight glass, and its associated valves, pipelines, and instruments. During normal operation, the sulfuric acid regulating valve automatically opens when the acidity of the ammonia absorption system is below 2% and closes when the acidity is above 6%.

[0081] The following embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0082]

Example

[0083] like Figure 1 As shown in this embodiment, the process flow of the coke oven gas deammoniation system for producing large-particle ammonium sulfate is as follows:

[0084] The coal gas from the external unit, awaiting ammonia removal, enters the coal gas heating system 8 through the coal gas inlet valve 1. After being heated to 60°C, it enters the ammonia absorption system 7 to absorb ammonia. Then, after passing through the mist eliminator 6 to separate fine acidic droplets, it is sent to the next unit through the coal gas outlet valve 2, reducing the ammonia content of the coal gas to 30 mg / Nm³. 3 the following.

[0085] A passage pipe and a passage valve 3 are installed between the upstream pipes of gas inlet valve 1 and gas outlet valve 2 for convenient use during maintenance of the ammonium sulfate unit.

[0086] The circulating ammonium sulfate mother liquor required by the ammonia absorption system 7 is provided by the large mother liquor circulation pump 21. In order to control the fine crystal content in the ammonium sulfate mother liquor, part of the ammonium sulfate mother liquor at the inlet end of the large mother liquor circulation pump 21 needs to pass through the mother liquor heating system 9. When the proportion of fine crystals with a particle size of less than 2 mm in the ammonium sulfate mother liquor reaches 35%, the mother liquor heating system 9 is started and shut down until the proportion drops to 30%.

[0087] The heat from both the gas heating system 8 and the mother liquor heating system 9 is controlled by the heat control system 10. The heat control system 10 includes an input parameter measurement module 11, an output parameter measurement module 12, a heat calculation module 13, and a heat control module 14 (controlled by a heat regulating valve 15).

[0088] The acidity of the ammonia absorption system 7 is regulated by the acidity control system 16, which includes an acidity measurement module 17, a sulfuric acid high-level tank 18, a sulfuric acid regulating valve 19, and an observation mirror 20. The acidity is controlled at 4%.

[0089] The liquid level of ammonium sulfate mother liquor in ammonia absorption system 7 is controlled by the full flow tank 25, the generated residue is collected by the residue tank 27, and the generated ammonium sulfate crystals are transported to subsequent processes by the crystallization pump 22. The mother liquor overflowing from ammonia absorption system 7 flows through the full flow tank 25 to the mother liquor storage tank 26, and is returned to ammonia absorption system 7 for spraying by the small mother liquor pump 23.

[0090] The ammonium sulfate produced by the coke oven gas deammonium removal system described in this embodiment has a particle size range of 400–3000 μm, which meets the production requirements for large-particle ammonium sulfate products.

[0091] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A coke oven gas ammonia removal system for producing large-particle ammonium sulfate, comprising an ammonia absorption system, a high-pressure sulfuric acid tank, a full-flow tank, a mother liquor storage tank, a crystallization pump, a large mother liquor circulation pump, and a small mother liquor pump; the gas inlet of the ammonia absorption system is connected to a coke oven gas pipeline via a gas inlet pipe, and a gas inlet valve is installed on the gas inlet pipe; the gas outlet of the ammonia absorption system is connected to a deammoniation gas pipeline via a gas outlet pipe, and a mist eliminator, a gas outlet valve, and a drain funnel are sequentially installed along the gas flow direction on the gas outlet pipe, and the drain funnel is connected to a gas liquid seal tank; the gas outlet pipe is connected to the gas inlet pipe via a traffic pipe, and a traffic valve is installed on the traffic pipe; the sulfuric acid outlet of the high-pressure sulfuric acid tank is connected to a sulfuric acid outlet pipe via a sulfuric acid outlet pipe. The ammonium sulfate mother liquor outlet of the mother liquor storage tank is connected to the ammonium sulfate mother liquor inlet of the ammonia absorption system via an ammonium sulfate mother liquor pipeline. Small mother liquor pumps and flow regulating valves are sequentially installed along the flow direction of the ammonium sulfate mother liquor on the ammonium sulfate mother liquor pipeline. The small mother liquor pumps and flow regulating valves are interlocked. The ammonium sulfate outlet of the ammonia absorption system is connected to a full-flow tank via an ammonium sulfate outlet pipeline. The full-flow tank is connected to the mother liquor storage tank via a full-flow mother liquor pipeline. The ammonia absorption system has a circulating mother liquor outlet connected to the circulating mother liquor inlet of the ammonia absorption system via a circulating mother liquor pipeline. A large mother liquor circulating pump is installed on the circulating mother liquor pipeline. The crystallized mother liquor outlet of the ammonia absorption system is connected to a crystallized mother liquor external delivery pipeline, which is equipped with a crystallization pump. Its features are, The coke oven gas deammoniation system also includes a gas heating system, a mother liquor heating system, an acidity control system, and a heat control system. The gas heating system is located on the gas inlet pipe. The ammonia absorption system has a circulating mother liquor outlet 2, which is connected to the circulating mother liquor pipe upstream of the large mother liquor circulation pump via a heated circulating mother liquor pipe. A mother liquor heating system is installed on the heated circulating mother liquor pipe. The acidity control system includes an acidity measurement module, a sulfuric acid regulating valve, and a sight glass. The acidity measurement module is located in the ammonia absorption system and is used to detect the acidity of the ammonium sulfate mother liquor. The high-pressure sulfuric acid tank has a regulating sulfuric acid outlet, which is connected to the ammonium sulfate outlet pipe and the circulating mother liquor pipe upstream of the large mother liquor circulation pump via a regulating sulfuric acid pipe. A sulfuric acid regulating valve and a sight glass are installed on the regulating sulfuric acid pipe. The acidity measurement module is interlocked with the sulfuric acid regulating valve. Both the gas heating system and the mother liquor heating system are connected to their respective heat control systems. The heat control system consists of a heat regulating valve, an input parameter measurement module, an output parameter measurement module, a heat calculation module, and a heat control module. The heat regulating valve is installed on the heat input pipe of the gas heating system and the heat input pipe of the mother liquor heating system, respectively. Input parameter measurement modules are installed on the gas inlet pipe upstream of the gas heating system and the heating circulation mother liquor pipe upstream of the mother liquor heating system, respectively. Output parameter measurement modules are installed on the gas inlet pipe downstream of the gas heating system and the heating circulation mother liquor pipe downstream of the mother liquor heating system, respectively. The control terminal of the heat control valve, the input parameter measurement module, the output parameter measurement module, and the heat calculation module are all connected to the heat control module.

2. The coke oven gas ammonia removal system for producing large-particle ammonium sulfate according to claim 1, characterized in that, The gas heating system is a steam heating system, an electric heating system, or a microwave heating system; the ammonia absorption system is a saturator or an acid washing tower; the mother liquor heating system is a steam heating system, an electric heating system, or a microwave heating system.

3. A method for removing ammonia from coke oven gas using the coke oven gas deammoniation system for producing large-particle ammonium sulfate as described in claim 1 or 2, characterized in that, By synergistically adjusting the water content, solubility, and acidity of the mother liquor, the growth rate of ammonium sulfate crystals is controlled, thereby reducing the amount of crystal nuclei formed and thus obtaining large-particle ammonium sulfate products; the specific process includes the following steps: 1) When the inlet gas temperature is below 40℃, turn on the gas heating system to heat the gas to 40-65℃, and control the water content in the ammonium sulfate mother liquor by controlling the gas temperature; this step is omitted when the outlet gas temperature is above 65℃. 2) The heated coal gas enters the ammonia absorption system, where sulfuric acid reacts with the ammonia in the coal gas to produce ammonium sulfate. After the sulfuric acid absorbs the ammonia, the ammonia content in the coal gas is below 30 mg / Nm³. 3 ; 3) The ammonium sulfate mother liquor is heated by a mother liquor heating system to form a local overheated zone, thereby controlling the solubility of the ammonium sulfate mother liquor and eliminating fine crystals; 4) The acidity of the ammonium sulfate mother liquor is controlled within the range of 2% to 6% by an acidity control system; 5) The heat from the gas heating system and the mother liquor heating system is precisely allocated through the heat control system; the heat control system includes an input parameter measurement module, an output parameter measurement module, a heat calculation module, and a heat control module; The variables measured by the input parameter measurement module include: the inlet temperature Tin of the coal gas / ammonium sulfate mother liquor and the inlet flow rate Qin of the coal gas / ammonium sulfate mother liquor; the variables measured by the output parameter measurement module include: the outlet temperature T of the coal gas / ammonium sulfate mother liquor. out q, the outlet flow rate of coal gas / ammonium sulfate mother liquor out The heat calculation module calculates the input heat Q of the gas heating system / mother liquor heating system based on the measured values ​​returned by the input parameter measurement module and the output parameter measurement module, respectively. in The output heat Q of the gas heating system / mother liquor heating system out And the supplementary heat QD of the gas heating system / mother liquor heating system, the calculation formula is: Q in =C in q in T in C in The specific heat of the input coal gas / ammonium sulfate mother liquor; Q out =C out q out T out C out The specific heat of the output coal gas / ammonium sulfate mother liquor; QD=Q out -Q in 。 4. The method for deammoniation of coke oven gas in the production of large-particle ammonium sulfate according to claim 3, characterized in that, The obtained large-particle ammonium sulfate has a particle size range of 400–3000 μm.

5. The method for deammoniation of coke oven gas in the production of large-particle ammonium sulfate according to claim 3, characterized in that, The gas heating system is heated by steam, electricity, or microwave.

6. The method for deammoniation of coke oven gas in the production of large-particle ammonium sulfate according to claim 3, characterized in that, The process of sulfuric acid absorbing ammonia is carried out in a saturator or acid washing tower.

7. The method for deammoniation of coke oven gas in the production of large-particle ammonium sulfate according to claim 3, characterized in that, The ammonium sulfate mother liquor is heated by steam, electricity, or microwave. The mother liquor heating system operates intermittently. When the proportion of fine crystals with a particle size of less than 2 mm reaches 35%, the mother liquor heating system is started. After the mother liquor heating system is started, when the proportion of fine crystals with a particle size of less than 2 mm is less than 30%, the mother liquor heating system is turned off.

8. The method for deammoniation of coke oven gas in the production of large-particle ammonium sulfate according to claim 7, characterized in that, When the mother liquor heating system stops operating, the heat control system automatically increases the heat supply of the gas heating system according to the preset value; conversely, when the mother liquor heating system is put into operation, the heat control system automatically reduces the heat supply of the gas heating system.

9. The method for deammoniation of coke oven gas in the production of large-particle ammonium sulfate according to claim 3, characterized in that, The amount of water carried out by the coal gas from the ammonia absorption system = the amount of water carried in by the coal gas + the amount of water carried in by other gases + the amount of water carried in by the sulfuric acid + the amount of water carried in by the centrifuge + the amount of water carried in by the tail gas scrubbing tower - the amount of water carried out by the ammonium sulfate after the centrifuge.

10. The method for deammoniation of coke oven gas in the production of large-particle ammonium sulfate according to claim 3, characterized in that, The heat supplied by the heat control system to the gas heating system is QDg, and the heat supplied to the mother liquor heating system is QDc; the total supplied heat ΣQ=QDg+QDc, that is, the total supplied heat = heat carried out by the gas + heat carried out by the wet ammonium sulfate + heat carried out by the mother liquor sent to the crystallization tank + heat loss in the saturator / acid washing tower - heat carried in by the gas - heat carried in by other gases - heat carried in by sulfuric acid - heat of sulfuric acid dilution - heat carried in by washing water - heat carried in the returned mother liquor - heat of ammonium sulfate formation - heat of ammonium sulfate crystallization.

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