Secondary salt treatment system for gas purification desulfurization solution
By using two evaporators in the gas purification desulfurization solution treatment system for two -stage separation and cyclone separator to separate the parallel salt, the problem of low work efficiency of the existing system and incomplete sub -salt extraction were solved, and efficient auxiliary salt extraction was achieved. Use ammonia water circulation.
Patent Information
- Application Number
- CN202421695796.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-17
- Publication Date
- 2025-01-28
- Estimated Expiration
- 2034-07-17
AI Technical Summary
The existing gas purification and desulfurization solution has low working efficiency and incomplete extraction of sub-salts, which affects the recycling of ammonia water.
The two -level evaporator with the same structure is used to separate the two -stage separation. The steam is used to heat the desulfurization solution to generate ammonia steam and separate the auxiliary salt through the whirlwind separator.
The efficient extraction of the auxiliary salt and the rapid separation of ammonia water have been achieved, which greatly reduces the sub -salt content in ammonia water, improves desulfurization efficiency, and is conducive to the circulation of ammonia water.
Smart Images
Figure CN222411469U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of coal gas desulfurization, in particular to a secondary salt processing system for coal gas purification desulfurization solution. Background Art
[0002] During the production process of a coking plant, nearly one-third of the sulfur will be transferred from the raw coal to the coke oven gas produced. In order to protect the environment, the coke oven gas must be desulfurized and purified. There are many desulfurization technologies in the coking industry. The most commonly used one is the HPF desulfurization process with ammonia as the alkali source. After desulfurization by this process, more secondary salts such as ammonium thiosulfate, ammonium sulfate and ammonium thiocyanate will be produced in the desulfurization solution. With the continuous recycling of the desulfurization solution, these secondary salts continue to accumulate in the desulfurization solution. When the total salt concentration reaches 300g / L, a part of it must be discharged and new desulfurization solution must be added, otherwise the activity of the desulfurization solution will be reduced and the desulfurization efficiency will be affected. Under this operation mode, a large amount of desulfurization solution will be generated and needs to be treated.
[0003] The traditional treatment method of desulfurization solution is to send it to the coal blending section and spray it on the coal. However, after the coal with desulfurization solution enters the coke oven, it will still be converted into sulfur-containing compounds such as sulfur dioxide and hydrogen sulfide at high temperature, and will eventually return to the desulfurization solution, which cannot fundamentally solve the problem. The desulfurization solution contains a large amount of secondary salts such as ammonium thiosulfate, ammonium sulfate and ammonium thiocyanate, which are inorganic salts with high economic value. If these secondary salts can be separated from the desulfurization solution, it can not only reduce the secondary salt content in the desulfurization solution, restore its desulfurization capacity, improve the desulfurization efficiency, but also generate higher economic benefits. At present, the existing device for extracting secondary salts from the desulfurization solution has a relatively single function, the extraction and processing procedures of the secondary salts are not perfect, the work efficiency is not high, and it is not conducive to the collection of secondary salt raw materials; secondly, the existing secondary salt treatment device has the problem of incomplete extraction of secondary salts in the desulfurization solution, and a certain amount of secondary salts still exist in the ammonia water obtained after treatment, which is not conducive to the recycling of ammonia water. Therefore, it is an objective need to develop a by-salt treatment system for gas purification and desulfurization solution with high working efficiency, thorough by-salt extraction, and conducive to the recycling of ammonia water. Utility Model Content
[0004] The utility model aims to provide a secondary salt treatment system for coal gas purification desulfurization solution which has high working efficiency, can extract secondary salt thoroughly and is conducive to the recycling of ammonia water.
[0005] The purpose of the utility model is achieved in this way, including two evaporators with the same structure, each evaporator is provided with a salt discharge port at the bottom, each evaporator is provided with a liquid inlet pipe at the bottom, the top of the previous evaporator is connected with a cyclone separator through a pipeline, the air outlet at the top of the cyclone separator is connected with a water cooler through a pipeline, the air outlet of the water cooler is connected with an ammonia tank through a pipeline, the outlet at the bottom of the cyclone separator is connected with the liquid inlet pipe of the rear evaporator through a pipeline, the top of the rear evaporator is connected with the air inlet of the water cooler through a pipeline, heat exchange tubes are provided in the two evaporators, the two heat exchange tubes are connected by a connecting pipe, and the air inlet end of the heat exchange tube in the previous evaporator is connected with a steam generator.
[0006] Furthermore, the lower ends of the two salt discharge ports are connected with screw conveyors.
[0007] Furthermore, the heat exchange tubes in the two evaporators are spiral coils, and an agitator is provided in the evaporator located inside the spiral coil.
[0008] Furthermore, after the stirring shaft of the stirrer extends into the bottom of the evaporator, it is connected to a scraper through a connecting rod, and the lower side of the scraper fits with the bottom surface of the evaporator.
[0009] Furthermore, the top of the ammonia water tank is connected to the air inlet of the water cooler through a pipeline.
[0010] Furthermore, the hot water outlet of the water cooler is connected to the water inlet of the steam generator through a pipeline, and the condensate outlet end of the heat exchange tube in the latter evaporator is connected to the water inlet of the water cooler.
[0011] The utility model is used for separating secondary salt from desulfurization solution to obtain ammonia water and mixed secondary salt. During operation, the coal gas purified desulfurization solution enters the previous evaporator from the liquid inlet pipe, and the steam generated by the steam generator is simultaneously passed into the heat exchange pipe in the previous evaporator, and the desulfurization solution is heated by the heat of the steam. After the desulfurization solution absorbs the heat of the steam, the ammonia water therein evaporates and enters the cyclone separator from the top of the evaporator, and the secondary salt mixed in the ammonia water vapor is separated by the action of centrifugal force, and the separated secondary salt enters the next evaporator to be heated again to generate ammonia water vapor again. The ammonia water vapor discharged from the cyclone separator and the next evaporator is sent to a water cooler for cooling, and the liquid ammonia water is sent to the ammonia water tank for storage and use, and the secondary salt after crystallization and sinking in the two evaporators is discharged from the salt discharge port. In the utility model, water vapor is used to heat the desulfurization solution to generate ammonia vapor, which is then cooled to obtain ammonia water, and at the same time, a mixed secondary salt of several ammonium salts is obtained from the bottom of the evaporator. The process is smooth and simple, the work efficiency is high, and the rapid separation of ammonia water and secondary salts can be achieved; secondly, the utility model uses two evaporators to perform two-stage separation on the desulfurization solution in turn, extracting the secondary salt components in the desulfurization solution as much as possible, greatly reducing the secondary salt content in the ammonia water, and facilitating the recycling of ammonia water. In summary, the utility model has the advantages of high work efficiency, thorough extraction of secondary salts, and facilitating the recycling of ammonia water. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 It is a schematic diagram of the overall structure of the utility model;
[0013] In the figure: 1-evaporator, 2-salt outlet, 3-liquid inlet pipe, 4-cyclone separator, 5-water cooler, 6-ammonia tank, 7-heat exchange tube, 8-connecting tube, 9-steam generator, 10-screw conveyor, 11-agitator, 12-scraper. DETAILED DESCRIPTION
[0014] The present invention is further described below in conjunction with the accompanying drawings, but the present invention is not limited in any way. Any changes or improvements made based on the present invention belong to the protection scope of the present invention.
[0015] like Figure 1As shown, the utility model includes two evaporators 1 with the same structure, each evaporator 1 is provided with a salt discharge port 2 at the bottom, each evaporator 1 is provided with a liquid inlet pipe 3 at the lower part, the top of the previous evaporator 1 is connected with a cyclone separator 4 through a pipeline, the air outlet at the top of the cyclone separator 4 is connected with a water cooler 5 through a pipeline, the air outlet of the water cooler 5 is connected with an ammonia tank 6 through a pipeline, the outlet at the bottom of the cyclone separator 4 is connected with the liquid inlet pipe 3 of the rear evaporator 1 through a pipeline, the top of the rear evaporator 1 is connected with the air inlet of the water cooler 5 through a pipeline, heat exchange tubes 7 are provided in the two evaporators 1, the two heat exchange tubes 7 are connected by a connecting pipe 8, and the air inlet end of the heat exchange tube 7 in the previous evaporator 1 is connected with a steam generator 9. In the present invention, the water cooler 5, the steam generator 9 and the ammonia water tank 6 are all existing equipment. The water cooler 5 uses cold water to condense the ammonia water vapor, the steam generator 9 is used to produce high-temperature water vapor, and the ammonia water tank 6 is used to store ammonia water.
[0016] The utility model is used to separate secondary salt from desulfurization solution to obtain ammonia water and mixed secondary salt. During operation, the gas-purified desulfurization solution enters the previous evaporator 1 from the liquid inlet pipe 3, and the steam generated by the steam generator 9 is passed into the heat exchange pipe 7 in the previous evaporator 1, and the heat of the steam is used to heat the desulfurization solution. After the desulfurization solution absorbs the heat of the steam, the ammonia water therein evaporates and enters the cyclone separator 4 from the top of the evaporator 1. The secondary salt mixed in the ammonia water vapor is separated by the effect of centrifugal force, and the separated secondary salt enters the next evaporator 1, is heated again, and ammonia water vapor is generated again. The ammonia water vapor discharged from the cyclone separator 4 and the next evaporator 1 is sent to the water cooler 5 for cooling, and the liquid ammonia water is sent to the ammonia water tank 6 for storage and use, and the secondary salt after crystallization and sinking in the two evaporators 1 is discharged from the salt discharge port 2. In the utility model, water vapor is used to heat the desulfurization solution to generate ammonia water vapor, which is then cooled to obtain ammonia water, and at the same time, a mixed secondary salt of several ammonium salts is obtained from the bottom of the evaporator 1. The process is smooth and simple, the working efficiency is high, and the rapid separation of ammonia water and secondary salts can be achieved; secondly, the utility model uses two evaporators 1 to perform two-stage separation on the desulfurization solution in turn, extracting the secondary salt components in the desulfurization solution as much as possible, greatly reducing the secondary salt content in the ammonia water, and facilitating the recycling of ammonia water. If necessary, a cyclone separator 4 can also be connected to the exhaust port at the top of the latter evaporator 1 to further separate the secondary salt components in the ammonia water vapor.
[0017] In order to facilitate the discharge of the secondary salt crystals in the evaporator 1 , a screw conveyor 10 is connected to the lower ends of the two salt discharge ports 2 .
[0018] The heat exchange tubes 7 in the two evaporators 1 are spiral coils, and a stirrer 11 is provided in the evaporator 1 located inside the spiral coil. The steam generated by the steam generator 9 flows in the spiral coil to heat the desulfurization solution in the evaporator 1. At the same time, the stirrer 11 stirs the desulfurization solution to keep the desulfurization solution in a flowing state, thereby improving the heating efficiency of the desulfurization solution and enabling the ammonia water in the desulfurization solution to evaporate quickly.
[0019] After the stirring shaft of the stirrer 11 extends into the bottom of the evaporator 1, it is connected to the scraper 12 through a connecting rod. The lower side of the scraper 12 is in contact with the bottom surface of the evaporator 1. The scraper 12 and the connecting rod rotate under the drive of the stirrer 11. On the one hand, the secondary salt crystals that have sunk to the bottom of the evaporator 1 are stirred and crushed to facilitate their discharge from the evaporator 1. On the other hand, the scraper 12 scrapes off the secondary salt adhered to the bottom of the evaporator 1 to prevent the secondary salt crystals from adhering to the bottom of the evaporator 1.
[0020] The top of the ammonia water tank 6 is connected to the air inlet of the water cooler 5 through a pipeline. The ammonia water in the desulfurization solution is heated and evaporated in the two evaporators 1, and then cooled by cold water in the water cooler 5. However, it is found in actual use that there is often a part of the ammonia water vapor that is not condensed into a liquid state. This part of the ammonia water vapor will be connected to the liquid ammonia water and sent to the ammonia water tank 6. If this part of the ammonia water vapor is not recovered, it may cause a waste of ammonia water. Therefore, this part of the ammonia water vapor is returned to the water cooler 5 through a pipeline for re-condensation to improve the recovery rate of ammonia water. In order to prevent the ammonia water vapor from being directly discharged into the ammonia water tank 6 without passing through the water cooler 5, a one-way valve can be set on the pipeline between the ammonia water tank 6 and the air inlet of the water cooler 5.
[0021] The hot water outlet of the water cooler 5 is connected to the water inlet of the steam generator 9 through a pipeline, and the condensate outlet end of the heat exchange tube 7 in the rear evaporator 1 is connected to the water inlet of the water cooler 5. When the water cooler 5 is in operation, cold water is used to absorb the heat of the ammonia vapor, so that the ammonia vapor is condensed and hot water is obtained at the same time. The hot water contains a large amount of heat, which is sent to the steam generator 9 for steam production, which can reduce the energy consumption of the steam generator 9, and at the same time recover the heat in the hot water to reduce heat loss; in addition, the steam generated by the evaporator generator 9 passes through the heat exchange tubes 7 in the two evaporators 1 in turn, completes the heating of the desulfurization solution, and its own temperature is reduced and condensed into condensed water, which is returned to the water cooler 5 for repeated use, which can reduce the consumption of water resources and avoid thermal pollution caused by condensed water discharge.
Claims
1. A secondary salt treatment system for coal gas purification desulfurization solution, comprising two evaporators (1) of the same structure, characterized in that : A salt discharge port (2) is provided at the bottom of each evaporator (1), a liquid inlet pipe (3) is provided at the bottom of each evaporator (1), the top of the previous evaporator (1) is connected to a cyclone separator (4) via a pipeline, the air outlet at the top of the cyclone separator (4) is connected to a water cooler (5) via a pipeline, the air outlet of the water cooler (5) is connected to an ammonia water tank (6) via a pipeline, the outlet at the bottom of the cyclone separator (4) is connected to the liquid inlet pipe (3) of the next evaporator (1) via a pipeline, the top of the next evaporator (1) is connected to the air inlet of the water cooler (5) via a pipeline, the two evaporators (1) are each provided with a heat exchange tube (7), the two heat exchange tubes (7) are connected via a connecting tube (8), and the air inlet end of the heat exchange tube (7) in the previous evaporator (1) is connected to a steam generator (9).
2. A secondary salt treatment system for coal gas purification and desulfurization solution according to claim 1, characterized in that The lower ends of the two salt discharge ports (2) are connected to a screw conveyor (10).
3. A secondary salt treatment system for coal gas purification and desulfurization solution according to claim 1, characterized in that The heat exchange tubes (7) in the two evaporators (1) are both spiral coils, and an agitator (11) is provided in the evaporator (1) located inside the spiral coil.
4. A secondary salt treatment system for coal gas purification and desulfurization solution according to claim 3, characterized in that The stirring shaft of the stirrer (11) extends into the bottom of the evaporator (1) and is connected to a scraper (12) via a connecting rod, and the lower side of the scraper (12) is in contact with the bottom surface of the evaporator (1).
5. The secondary salt treatment system for coal gas purification and desulfurization solution according to claim 1, characterized in that The top of the ammonia water tank (6) is connected to the air inlet of the water cooler (5) through a pipeline.
6. A secondary salt treatment system for coal gas purification and desulfurization solution according to claim 1, characterized in that The hot water outlet of the water cooler (5) is connected to the water inlet of the steam generator (9) through a pipeline, and the condensate outlet end of the heat exchange tube (7) in the rear evaporator (1) is connected to the water inlet of the water cooler (5).