An ammonium sulfate external crystallization auxiliary device and process

Abstract

The present application relates to coke oven gas ammonia recovery technical field, especially to a kind of ammonium sulfate external crystallization auxiliary device and process.It includes external crystallization tank, external crystallization tank circulating pump, external crystallization tank liquid level meter, regulating valve and flowmeter;Saturated ammonium sulfate crystallization tank outlet ammonium sulfate slurry pipeline is connected with the first branch pipeline of external crystallization tank inlet, regulating valve and flowmeter are set on the first branch pipeline;Saturated ammonium sulfate crystallization tank inlet ammonium sulfate mother liquor pipeline is connected with the second branch pipeline of external crystallization tank inlet;External crystallization tank liquid level meter is installed on external crystallization tank;External crystallization tank circulating pump inlet is connected with the first pipeline by pipeline, and external crystallization tank circulating pump outlet is connected with external crystallization tank by pipeline.The remaining ammonium sulfate crystals that saturated ammonium sulfate crystallization tank cannot be handled in time are sent into external crystallization tank, space is provided for crystal to continue to grow, crystallization time is extended, and product quality is ensured while increasing crystallization processing capacity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coke oven gas ammonia recovery, and particularly relates to a sulfur ammonium external crystallization auxiliary device and process. BACKGROUND

[0002] In the process of gas purification, ammonia in the gas is absorbed by sulfuric acid to produce ammonium sulfate, which is one of the important chemical products produced in large quantities in coking plants.

[0003] Most large coking plants in China use saturators to produce ammonium sulfate. The equipment processing capacity of the saturator is usually determined by the gas processing capacity. The production of ammonium sulfate is not only affected by the gas processing capacity, but also depends on the amount of ammonia in the gas, which is greatly affected by the previous process and raw material composition. Therefore, even if the gas processing capacity is the same, the ammonium sulfate production may be different, and therefore the crystallization time in the lower crystallization chamber of the saturator may not be sufficient.

[0004] If the crystallization time is too short, the small ammonium sulfate crystals will not have enough time to grow to the required size, thereby reducing the product quality. The degree of crystallization in the mother liquor is generally represented by the crystal ratio, that is, the percentage of the volume of crystals contained in the mother liquor to the total volume of the mother liquor and crystals.

[0005] The crystal ratio needs to be properly controlled. When the crystal ratio is too high, the volume for the reaction of ammonia and sulfuric acid is relatively reduced, which is not conducive to the absorption of ammonia and increases the resistance of the mother liquor stirring, resulting in poor stirring of the mother liquor and causing equipment blockage. Usually when the crystal ratio reaches 30%, the material is removed, and when the crystal ratio is reduced to 10%, the process is stopped. When the ammonia content in the gas increases sharply due to the previous production or raw material problems, the size of the crystalline particles is small, and the crystal ratio of the mother liquor is high under the same crystallization time, thereby forcing the material to be removed for drying, thereby reducing the product quality. The reason for the sharp change in the ammonia content in the gas may be temporary or permanent.

[0006] For a newly built ammonium sulfate unit, temporary fluctuations in ammonia content cannot be predicted at the beginning of the design, and blindly expanding the equipment size will cause unnecessary waste of funds and energy. For an existing ammonium sulfate unit, the problem of permanent ammonium sulfate processing capacity greater than the design processing capacity of the equipment often occurs due to process adjustment or raw material change after production, and the previous treatment method can only be to stop production and replace the saturator, which has high modification cost and difficulty. SUMMARY

[0007] In order to overcome the shortcomings of the prior art, the present application provides an ammonium sulfate external crystallization auxiliary device and process, which sends the remaining ammonium sulfate crystals that cannot be processed in time in the saturator ammonium sulfate crystallization tank to the external crystallization tank, provides space for the growth of the crystals, prolongs the crystallization time, increases the crystallization processing capacity, and ensures the product quality.

[0008] In order to achieve the above object, the present application adopts the following technical solutions:

[0009] An ammonium sulfate external crystallization auxiliary device, comprising an external crystallization tank (1), an external crystallization tank circulating pump (2), an external crystallization tank liquid level meter (3), an adjusting valve (4) and a flow meter (5); an ammonium sulfate slurry pipeline at the outlet of a saturator ammonium sulfate crystallization tank (6) is connected with the inlet of the external crystallization tank (1) through a first branch pipeline, and the adjusting valve (4) and the flow meter (5) are arranged on the first branch pipeline; an ammonium sulfate mother liquor pipeline at the inlet of the saturator ammonium sulfate crystallization tank (6) is connected with the inlet of the external crystallization tank (1) through a second branch pipeline; the external crystallization tank liquid level meter (3) is installed on the external crystallization tank (1); the inlet of the external crystallization tank circulating pump (2) is connected with the first pipeline through a pipeline, and the outlet of the external crystallization tank circulating pump (2) is connected with the external crystallization tank (1) through a pipeline.

[0010] Further, the external crystallization tank (1) and the saturator ammonium sulfate crystallization tank (6) are connected in parallel through pipelines.

[0011] Further, the external crystallization tank (1) and the saturator ammonium sulfate crystallization tank (6) are connected in series through pipelines.

[0012] Further, the upper part and the lower part of the external crystallization tank (1) are connected with the external crystallization tank circulating pump (2) through pipelines.

[0013] Further, the adjusting valve (4) and the flow meter (5) are interlocked, the flow meter (5) adjusts and controls the adjusting valve (4), and the full-flow tank liquid level meter (7) interlocks to control the adjusting valve (4).

[0014] An ammonium sulfate external crystallization auxiliary process, specifically comprising:

[0015] 1) If the crystalline particles of the saturator ammonium sulfate crystallization tank (6) are smaller than the required material, the crystallization pump (8) starts to supply material to the external crystallization tank (1), and at this time, the external crystallization tank circulating pump (2) does not work;

[0016] When the crystallization pump (8) stops supplying material to the external crystallization tank (1), at this time, the external crystallization tank circulating pump (2) starts to work and circulates and stirs the mother liquor;

[0017] 2) When the external crystallization tank liquid level meter (3) shows that the liquid level is higher than the outlet of the external crystallization circulating pump (2) and higher than the set alarm value, the external crystallization circulating pump (2) draws material (c) from the upper part of the external crystallization tank (1) and supplies material (d) from the bottom of the external crystallization tank (1), and circulates and stirs the inside of the external crystallization tank (1) to prevent material accumulation at the bottom;

[0018] 3) When the liquid level gauge (3) of the external crystallization tank shows that the liquid level is lower than the set value, the material is drawn from the bottom of the external crystallization tank (1) (a) and fed from the top of the external crystallization tank (1) (b);

[0019] 4) When it is necessary to extract material from the external crystallization tank (1), close the inlet valve from the saturator (9) to the crystallization pump (8), open the inlet valve from the external crystallization tank (1) to the crystallization pump (8), and send the mother liquor to the saturator ammonium sulfate crystallization tank (6) through the crystallization pump (8);

[0020] 5) When the saturator ammonium sulfate crystallization tank (6) and the external crystallization tank (1) are operated in parallel, the full flow mother liquor of the two crystallization tanks is returned to the saturator (9) together;

[0021] During series operation, the full-flow mother liquor from the ammonium sulfate crystallization tank (6) of the saturator enters the external crystallization tank (1) and then flows back to the saturator (9) to prolong the crystallization time.

[0022] 6) When feeding ammonium sulfate crystallizing tank (6) and external crystallizing tank (1) at the same time, the ratio relationship is set and controlled manually according to the actual production situation; the regulating valve (4) is interlocked through the full flow tank level gauge (7). When the full flow tank level is lower than the set value, the regulating valve (4) is cut off to ensure the water seal requirements of the full flow tank.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. It does not affect the original process and is only activated when the original equipment cannot meet the processing requirements. At other times, it is in standby mode, saving energy and increasing the stability and flexibility of the equipment operation.

[0025] 2. It can realize the expansion and renovation of old equipment without interrupting production, without the need to modify the original equipment, with short renovation time, low investment in additional equipment, and easy implementation.

[0026] 3. It can be connected in series or in parallel with the existing crystallization tank, allowing for flexible operation.

[0027] 4. The matching external crystallization tank circulation pump can circulate and agitate the mother liquor in the crystallization tank when no material is being pumped, promoting crystallization and preventing equipment blockage.

[0028] 5. Switch the crystallization pump's pumping and feeding positions according to the liquid level to ensure stable operation.

[0029] 6. Equipped with regulating valves and flow meters, the feed flow rate can be automatically controlled according to production conditions.

[0030] 7. The regulating valve and the full-flow level gauge are interlocked to ensure safe and stable production.

[0031] 8. The equipment occupies a small area, and the number of external crystallization tanks can be increased according to production needs, making it flexible and adaptable. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure and process principle of the present invention.

[0033] In the diagram: 1-External crystallization tank; 2-External crystallization tank circulation pump; 3-External crystallization tank level gauge; 4-Regulating valve; 5-Flow meter; 6-Saturator, ammonium sulfate crystallization tank; 7-Full flow tank level gauge; 8-Crystallization pump; 9-Saturator Detailed Implementation

[0034] This invention discloses an external crystallization auxiliary device and process for ammonium sulfate. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments, and those skilled in the art can obviously make modifications or appropriate alterations and combinations to the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0035] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0036] like Figure 1 As shown, an external crystallization auxiliary device for ammonium sulfate includes an external crystallization tank (1), an external crystallization tank circulation pump (2), an external crystallization tank level gauge (3), a regulating valve (4), and a flow meter (5). The ammonium sulfate slurry pipeline at the outlet of the saturator ammonium sulfate crystallization tank (6) has a first branch pipeline connected to the inlet of the external crystallization tank (1), and the regulating valve (4) and flow meter (5) are installed on the first branch pipeline. The ammonium sulfate mother liquor pipeline at the inlet of the saturator ammonium sulfate crystallization tank (6) has a second branch pipeline connected to the inlet of the external crystallization tank (1). The external crystallization tank level gauge (3) is installed on the external crystallization tank (1). The inlet of the external crystallization tank circulation pump (2) is connected to the first pipeline via a pipeline, and the outlet of the external crystallization tank circulation pump (2) is connected to the external crystallization tank (1) via a pipeline.

[0037] Furthermore, the external crystallization tank (1) and the saturator ammonium sulfate crystallization tank (6) are connected in parallel via pipelines. This increases the volume of the ammonium sulfate crystallization equipment, allowing for flexible adjustment of the ammonium sulfate crystallization time according to actual production conditions.

[0038] Furthermore, the external crystallization tank (1) and the saturator ammonium sulfate crystallization tank (6) are connected in series via pipelines. This allows for multi-stage crystallization of the particles.

[0039] Furthermore, both the upper and lower parts of the external crystallization tank (1) are connected to the external crystallization tank circulation pump (2) via pipes. The feeding method of the external circulation pump (2) is adjusted according to the liquid level indicated by the external crystallization tank level gauge (3), selecting feeding from the upper or lower part.

[0040] Furthermore, the regulating valve (4) is interlocked with the flow meter (5). The flow meter (5) regulates and controls the regulating valve (4), and the full-flow tank level gauge (7) is interlocked and controls the regulating valve (4). The flow meter (5) regulates the material flow into the external crystallization tank (1) through the regulating valve (4) according to the actual production situation; the full-flow tank level gauge (7) regulates and controls the regulating valve (4) to prevent the full-flow tank from failing to meet the water seal requirements, thus enabling the system to operate automatically and stably.

[0041] An external crystallization-assisted process for ammonium sulfate specifically includes:

[0042] When the crystal ratio of the saturator (9) is too high, but the crystallized particles are smaller than the material lifting requirements, the crystallization pump starts to supply material to the external crystallization tank (1). At this time, the external crystallization tank circulation pump (2) does not work. When the crystallization pump stops supplying material to the external crystallization tank (1), the external crystallization tank circulation pump (2) starts to work, circulating and stirring the mother liquor to promote crystallization and prevent excessive accumulation of crystals, which would cause difficulties in material lifting.

[0043] Meanwhile, when the external crystallization tank level gauge (3) shows that the liquid level is higher than the outlet of the external crystallization circulation pump (2) and higher than the set alarm value, the external crystallization circulation pump (2) draws material from the top of the external crystallization tank (1) (c) and supplies material from the bottom of the external crystallization tank (1) (d), effectively circulating and agitating the inside of the external crystallization tank (1) to prevent material from piling up at the bottom.

[0044] When the external crystallization tank level gauge (3) shows that the liquid level is lower than the set value, the material is pumped from the bottom of the external crystallization tank (1) (a) and supplied from the top of the external crystallization tank (1) (b). By switching the working pipeline of the external crystallization circulation pump (2) by the liquid level, the crystallization can be effectively agitated, the system can be kept stable, and the material cannot be pumped when the liquid level of the crystallization tank is too low.

[0045] When it is necessary to extract material from the external crystallization tank (1), the inlet valve from the saturator to the crystallization pump (8) is closed, and the inlet valve from the external crystallization tank (1) to the crystallization pump (8) is opened, so that the mother liquor is sent to the original crystallization tank through the crystallization pump.

[0046] The ammonium sulfate crystallizing tank (6) and the external crystallizing tank (1) can be operated in series or in parallel. In parallel operation, the full-flow mother liquor from both crystallizing tanks returns to the saturator together; in series operation, the full-flow mother liquor from the ammonium sulfate crystallizing tank (6) enters the external crystallizing tank (1) and then flows back to the saturator (9), extending the crystallization time.

[0047] This process design includes a regulating valve (4) and a flow meter (5), which can simultaneously supply material to the ammonium sulfate crystallization tank (6) in the saturator and the external crystallization tank (1), and the proportional relationship can be manually set and controlled according to the actual production situation. The regulating valve (4) is interlocked with the full-flow tank level gauge (7). When the full-flow tank level is lower than the set value, the regulating valve (4) is shut off to ensure the water seal requirements of the full-flow tank and to ensure the automatic, safe and stable operation of the system.

[0048] The ammonia content in coal gas is greatly affected by the preceding processes and raw material composition. When the ammonium sulfate crystallization output exceeds the equipment's designed processing capacity, the crystallization time is shortened, resulting in excessively small ammonium sulfate crystal particles and reduced product quality. This invention is an external crystallization auxiliary process for ammonium sulfate. It sends the remaining ammonium sulfate crystals that the original equipment cannot process in time to an external crystallization tank, providing space for continued crystal growth, extending the crystallization time, increasing the crystallization throughput, and ensuring product quality. For newly built equipment, this process can serve as an auxiliary device to increase operational flexibility; for existing equipment, it allows for non-stop production upgrades. This invention has significant advantages such as simple, complete, and reasonable process, easy operation, low cost, low investment, and energy savings.

[0049] 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. An external crystallization assisted process for ammonium sulfate characterized in that, The device comprises an external crystallization tank (1), an external crystallization tank circulating pump (2), an external crystallization tank liquid level meter (3), an adjusting valve (4) and a flow meter (5); the ammonium sulfide slurry pipeline at the outlet of the saturator ammonium sulfide crystallization tank (6) is provided with a first branch pipeline connected with the inlet of the external crystallization tank (1), the adjusting valve (4) and the flow meter (5) are arranged on the first branch pipeline; the ammonium sulfide mother liquor pipeline at the inlet of the saturator ammonium sulfide crystallization tank (6) is provided with a second branch pipeline connected with the inlet of the external crystallization tank (1); the external crystallization tank liquid level meter (3) is installed on the external crystallization tank (1); the inlet of the external crystallization tank circulating pump (2) is connected with the first pipeline through a pipeline, and the outlet of the external crystallization tank circulating pump (2) is connected with the external crystallization tank (1) through a pipeline; The external crystallization tank (1) and the saturator ammonium sulfide crystallization tank (6) are connected in parallel through pipelines; the external crystallization tank (1) and the saturator ammonium sulfide crystallization tank (6) are connected in series through pipelines; The upper part and the lower part of the external crystallization tank (1) are connected with the external crystallization tank circulating pump (2) through pipelines; The adjusting valve (4) is interlocked with the flow meter (5), the flow meter (5) adjusts and controls the adjusting valve (4), and the full-flow tank liquid level meter (7) interlocks to control the adjusting valve (4); Specifically comprising: 1) if the crystalline particles of the saturator ammonium sulfide crystallization tank (6) are smaller than the requirement of taking out the material, the crystallization pump (8) starts to supply material to the external crystallization tank (1), at this time, the external crystallization tank circulating pump (2) does not work; When the crystallization pump (8) stops supplying material to the external crystallization tank (1), at this time, the external crystallization tank circulating pump (2) starts to work and circulates and stirs the mother liquor; 2) when the external crystallization tank liquid level meter (3) shows that the liquid level is higher than the outlet of the external crystallization tank circulating pump (2) and is higher than the set alarm value, the external crystallization tank circulating pump (2) draws material (c) from the upper part of the external crystallization tank (1) and supplies material (d) from the bottom of the external crystallization tank (1), so as to circulate and stir the inside of the external crystallization tank (1) and prevent the bottom from being piled up; 3) when the external crystallization tank liquid level meter (3) shows that the liquid level is lower than the set value, the material (a) is drawn from the bottom of the external crystallization tank (1) and the material (b) is supplied from the top of the external crystallization tank (1); 4) when it is necessary to take out the material from the external crystallization tank (1), the inlet valve from the saturator (9) to the crystallization pump (8) is closed, the inlet valve from the external crystallization tank (1) to the crystallization pump (8) is opened, and the mother liquor is sent to the saturator ammonium sulfide crystallization tank (6) through the crystallization pump (8); 5) when the saturator ammonium sulfide crystallization tank (6) and the external crystallization tank (1) are operated in parallel, the full-flow mother liquor of the two crystallization tanks returns to the saturator (9) together; When the saturator ammonium sulfide crystallization tank (6) and the external crystallization tank (1) are operated in series, the full-flow mother liquor of the saturator ammonium sulfide crystallization tank (6) enters the external crystallization tank (1) and then returns to the saturator (9), so as to prolong the crystallization time; 6) when the saturator ammonium sulfide crystallization tank (6) and the external crystallization tank (1) are supplied with material at the same time, the proportional relationship is artificially set and controlled according to the actual production situation; the full-flow tank liquid level meter (7) interlocks to control the adjusting valve (4), when the liquid level of the full-flow tank is lower than the set value, the adjusting valve (4) is cut off, so as to ensure the water sealing requirement of the full-flow tank.

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