Ammonium bicarbonate desorption regeneration system
By using the high-temperature flue gas before desulfurization as a heat source to heat the ammonium bicarbonate rich liquid in the ammonium bicarbonate desorption tower, and setting up a scrubber to remove ammonia during the desorption and regeneration process, the problems of high desorption and regeneration of ammonia and poor carbon dioxide separation and purification effect in the prior art are solved, and efficient and low-cost carbon dioxide purification effect is achieved.
Patent Information
- Application Number
- CN202421928138.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-09
- Publication Date
- 2025-06-03
- Estimated Expiration
- 2034-08-09
AI Technical Summary
The existing ammonium bicarbonate desorption and regeneration methods have problems with high energy consumption and poor carbon dioxide separation and purification effects. Especially in ammonia decarbonization systems, the high volatility of ammonia water leads to the crystallization of ammonium bicarbonate, causing difficulties in the system to operate.
The high-temperature flue gas before desulfurization is used as the heat source, and the ammonium bicarbonate rich liquid in the ammonium bicarbonate desorption tower is heated through the thermal medium water circulation heater, and a scrubber is set up during the desorption and regeneration process to remove the ammonia in the mixed gas to avoid crystallization of ammonium bicarbonate.
It effectively reduces the desorption and regeneration cost of ammonium bicarbonate, improves the purity of carbon dioxide to more than 99.5%, avoids pipeline blockage and system failure, and reduces maintenance costs.
Smart Images
Figure CN222930588U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of gas separation and purification equipment, and particularly relates to a desorption and regeneration system for ammonium bicarbonate. Background Art
[0002] With the increasingly serious global climate problem, carbon dioxide emission reduction has become a consensus. China conforms to the trend of low-carbon development, actively responds to the carbon emission reduction action, and puts forward the goals of "carbon peak and carbon neutrality". Among them, the CCUS technology is an indispensable technology to achieve the low-carbon goal and realize carbon emission reduction. This technology can significantly reduce anthropogenic carbon dioxide emissions while meeting the current growing energy demand. In CCUS, the chemical absorption method of carbon dioxide is generally considered as one of the most promising carbon emission reduction technologies due to its large absorption capacity and fast absorption rate, and will play a huge role in the energy-saving and carbon-reducing transformation of coal-fired power generation in the future. Among them, the ammonia-based decarbonization process has strong adaptability and good decarbonization effect, and has become an important carbon emission reduction technology.
[0003] The process of the ammonia-based decarbonization process system includes two processes: carbon dioxide absorption and desorption regeneration. Among them, the absorption process is mainly that the flue gas after desulfurization and dust removal enters from the bottom of the absorption tower and contacts countercurrently with the ammonia water solution sprayed from top to bottom in the absorption tower, so as to carry out the heat and mass transfer process of gas-liquid two-phase. In this process, a rich liquid containing ammonium bicarbonate will be generated. The desorption and regeneration process is mainly carried out for the ammonium bicarbonate rich liquid generated in the absorption process. The common desorption and regeneration is mainly by feeding the generated ammonium bicarbonate rich liquid into the top of the desorption tower and contacting it countercurrently with the high-temperature steam generated from the reboiler at the bottom of the tower. Under the action of temperature and pressure, the carbon dioxide in the rich liquid is regenerated and precipitated in the desorption tower. The generated carbon dioxide-containing gas is cooled, dried and compressed, and stored in a gas storage tank for subsequent use.
[0004] However, this method requires a large amount of steam to be introduced at the bottom of the desorption tower, which will generate huge energy consumption and make the desorption and regeneration cost too high. And in order to obtain high-purity carbon dioxide products, it is necessary to cool the gas-phase mixture regenerated at the top of the desorption tower to condense the water vapor therein, and then carry out gas-liquid separation to obtain the product. The liquid phase is re-introduced into the desorption tower to achieve system water balance. This operation is widely used in the organic ammonia-based decarbonization system. However, for the ammonia-based decarbonization system, the high volatility of ammonia water makes this process accompanied by the reaction of carbon dioxide and ammonia, and crystallization of ammonium bicarbonate may occur in the liquid phase. The crystallization precipitates at low temperature and accumulates in the condenser and subsequent reflux pipelines, and finally blocks the pipelines, causing difficulties in system operation.
[0005] From the above background, it is known that although there are several methods for desorbing and regenerating ammonium bicarbonate, there are problems to varying degrees in these methods. To solve these methods, an ammonium bicarbonate desorption and regeneration system is proposed. The high-temperature flue gas before desulfurization is used as a heat source to provide heat for the desorption and regeneration of ammonium bicarbonate through a heat medium water circulation heater. And a washing tower is set before the mixed gas obtained by desorption and regeneration is condensed. In the washing tower, ammonia is removed from the gas desorbed and regenerated to reduce the large amount of crystallization of ammonium bicarbonate during the condensation process, thus blocking the pipeline. Utility Model Content
[0006] The technical problem to be solved by the present utility model is to provide an ammonium bicarbonate desorption and regeneration system.
[0007] To solve the above technical problems, the technical solution of the present utility model is as follows:
[0008] An ammonium bicarbonate desorption and regeneration system includes a circulation pump, a heat medium water circulation heater, a rich and lean liquid heat exchanger, a lean liquid pump, an ammonium bicarbonate desorption tower, a washing tower, a circulation water pump, a gas-liquid separator, a condenser, a dryer, a compressor, and a storage tank; an absorption spray layer is provided in the washing tower, a packing layer is provided in the washing tower above the absorption spray layer, and a demisting spray layer is provided above the packing layer in the washing tower; a rich ammonia water outlet is provided at the lower end of the washing tower; the liquid outlet end of the circulation water pump is communicated with the liquid inlet end of the absorption spray layer, and the liquid suction end of the circulation water pump is communicated with the lower end of the inner cavity of the washing tower; the liquid suction end of the lean liquid pump is communicated with the lower end of the inner cavity of the ammonium bicarbonate desorption tower, and the liquid outlet end is communicated with the inlet of the second fluid channel of the rich and lean liquid heat exchanger; the outlet of the second fluid channel of the rich and lean liquid heat exchanger is used to discharge ammonium bicarbonate lean liquid; the outlet of the first fluid channel of the rich and lean liquid heat exchanger is communicated with the inside of the ammonium bicarbonate desorption tower; the inlet of the first fluid channel of the rich and lean liquid heat exchanger is used to introduce ammonium bicarbonate rich liquid; the liquid suction end of the circulation pump is communicated with the lower part of the inner cavity of the ammonium bicarbonate desorption tower, and the liquid outlet end is communicated with the inlet of the first fluid channel of the heat medium water circulation heater, and the outlet of the first fluid channel of the heat medium water circulation heater is communicated with the upper part of the inner cavity of the ammonium bicarbonate desorption tower; the inlet of the second fluid channel of the heat medium water circulation heater is used to introduce high-temperature flue gas before desulfurization, and the outlet is used to discharge the flue gas after heat exchange; the exhaust end of the washing tower is communicated with the inlet of the condenser, the outlet of the condenser is communicated with the inlet of the gas-liquid separator, the exhaust end of the gas-liquid separator is communicated with the inlet of the dryer, the outlet of the dryer is communicated with the inlet of the compressor, and the inlet of the compressor is communicated with the inlet of the storage tank.
[0009] Preferably, the high-temperature flue gas before desulfurization is used as a heat source in the heat medium water circulation heater.
[0010] Preferably, the rich and lean liquid heat exchanger adopts a plate heat exchanger.
[0011] Preferably, the condenser adopts a natural air convection condenser.
[0012] Adopting the above technical solution has the following advantages:
[0013] 1. The utility model uses the high-temperature flue gas before desulfurization as a heat source, and heats and decomposes ammonium bicarbonate in the ammonium bicarbonate desorption tower through a heat medium water circulation heater.
[0014] 2. The mixed gas of water vapor, ammonia and carbon dioxide generated during the desorption and regeneration process of ammonium bicarbonate in the utility model is first introduced into the washing tower. After most of the ammonia is removed in the washing tower, the water vapor and the remaining ammonia are removed by cooling to avoid the crystallization of ammonium bicarbonate.
[0015] 3. The structure of the utility model is reasonably designed, and the purity of carbon dioxide can reach more than 99.5%, effectively solving the technical problems of high cost of ammonium bicarbonate desorption and regeneration and poor separation and purification effect of carbon dioxide at present. Description of the Drawings
[0016] Figure 1 is a structural schematic diagram of the utility model;
[0017] In the figure:
[0018] 1 - high-temperature flue gas before desulfurization, 2 - flue gas after heat exchange, 3 - circulation pump, 4 - heat medium water circulation heater, 5 - rich and lean liquid heat exchanger, 6 - rich ammonium bicarbonate solution, 7 - lean ammonium bicarbonate solution, 8 - lean liquid pump, 9 - ammonium bicarbonate desorption tower, 10 - absorption spray layer, 11 - outlet of rich ammonia water, 12 - circulation water pump, 13 - packing layer, 14 - washing tower, 15 - demisting spray layer, 16 - gas-liquid separator, 17 - condenser, 18 - dryer, 19 - compressor, 20 - storage tank. Detailed Embodiments
[0019] The following further describes the detailed embodiments of the utility model with reference to the drawings. It should be noted here that the description of these embodiments is for helping to understand the utility model, but does not constitute a limitation to the utility model. In addition, the technical features involved in the various embodiments of the utility model described below can be combined with each other as long as they do not conflict with each other.
[0020] As shown in the atta Figure 1As shown in the figure, an ammonium bicarbonate desorption and regeneration system includes a circulation pump 3, a heat medium water circulation heater 4, a rich and lean liquid heat exchanger 5, a lean liquid pump 8, an ammonium bicarbonate desorption tower 9, a washing tower 14, a circulating water pump 12, a gas-liquid separator 16, a condenser 17, a dryer 18, a compressor 19, and a storage tank 20; an absorption spray layer 10 is arranged inside the washing tower 14, a packing layer 13 is arranged above the absorption spray layer 10 inside the washing tower 14, and a demisting spray layer 15 is arranged above the packing layer 13 inside the washing tower 14; a rich ammonia water outlet 11 is arranged at the lower end of the washing tower 14; the liquid outlet end of the circulating water pump 12 is communicated with the liquid inlet end of the absorption spray layer 10, and the liquid suction end of the circulating water pump 12 is communicated with the lower end of the inner cavity of the washing tower 14; the liquid suction end of the lean liquid pump 8 is communicated with the lower end of the inner cavity of the ammonium bicarbonate desorption tower 9, and the liquid outlet end is communicated with the inlet of the second fluid channel of the rich and lean liquid heat exchanger 5; the outlet of the second fluid channel of the rich and lean liquid heat exchanger 5 is used for discharging ammonium bicarbonate lean liquid 7; the outlet of the first fluid channel of the rich and lean liquid heat exchanger 5 is communicated with the inner cavity of the ammonium bicarbonate desorption tower 9; the inlet of the first fluid channel of the rich and lean liquid heat exchanger 5 is used for introducing ammonium bicarbonate rich liquid 6; the liquid suction end of the circulation pump 3 is communicated with the lower part of the inner cavity of the ammonium bicarbonate desorption tower 9, and the liquid outlet end is communicated with the inlet of the first fluid channel of the heat medium water circulation heater 4, and the outlet of the first fluid channel of the heat medium water circulation heater 4 is communicated with the upper part of the inner cavity of the ammonium bicarbonate desorption tower 9; the inlet of the second fluid channel of the heat medium water circulation heater 4 is used for introducing high-temperature flue gas 1 before desulfurization, and the outlet is used for discharging the heat-exchanged flue gas 2; the exhaust end of the washing tower 14 is communicated with the inlet of the condenser 17, the outlet of the condenser 17 is communicated with the inlet of the gas-liquid separator 16, the exhaust end of the gas-liquid separator 16 is communicated with the inlet of the dryer 18, the outlet of the dryer 18 is communicated with the inlet of the compressor 19, and the inlet of the compressor 19 is communicated with the inlet of the storage tank 20.
[0021] In this embodiment, the rich and lean liquid heat exchanger 5 is preferably a plate heat exchanger. Obviously, other types of heat exchangers can also be used.
[0022] As a preferred technical solution of this embodiment, the condenser 17 adopts an air natural convection condenser that is easy to maintain. Obviously, other types of condensers can also be used.
[0023] In this embodiment, devices such as the circulation pump 3, the lean liquid pump 8, the circulating water pump 12, the dryer 18, the compressor 19, and the storage tank 20 are all existing devices and will not be elaborated here.
[0024] The working process is as follows:
[0025] The ammonium bicarbonate rich solution 6 obtained from the decarbonization system enters the ammonium bicarbonate desorption tower 9 through the inlet first via the lean-rich solution heat exchanger 5. The medium water in the heat medium water circulation heater 4 will be sent into the heat medium water circulation heater 4 through the circulation pump 3 to realize the circulating heating of the medium water in the ammonium bicarbonate desorption tower 9. In the heat medium water circulation heater 4, the medium water is heated by the high-temperature flue gas 1 before desulfurization as the heat source. Subsequently, the ammonium bicarbonate rich solution 6 in the ammonium bicarbonate desorption tower 9 is heated to 70 - 80 degrees Celsius, and then returns to the ammonium bicarbonate desorption tower 9 to complete the desorption and regeneration of the ammonium bicarbonate solution. After desorption and regeneration, the lean solution reaches the lean-rich solution heat exchanger 5 through the lean solution pump 8, and is discharged for standby after heat exchange. The mixed gas composed of ammonia gas, water vapor and carbon dioxide generated by desorption and regeneration exits from the top exhaust end of the ammonium bicarbonate desorption tower 9 and enters the washing tower 14. The mixed gas will remove the ammonia gas in the mixed gas through the absorption spray layer 10, the packing layer 13 and the demisting spray layer 15. The generated ammonia-rich solution returns to the decarbonization system from the ammonia-rich water outlet 11 for decarbonization. The gas after ammonia removal enters the condenser 17 to condense and remove the water vapor and the remaining small amount of ammonia gas in the ammonia-removed gas. Then, the carbon dioxide gas and the liquid are separated through the gas-liquid separator 16. The separated liquid returns to the decarbonization system. Finally, the carbon dioxide gas is dried through the dryer 18 and then compressed by the compressor 19 and sent to the storage tank 20 for pressurized storage for subsequent use.
[0026] The utility model uses the high-temperature flue gas 1 before desulfurization as the heat source, and heats and decomposes the ammonium bicarbonate rich solution in the ammonium bicarbonate desorption tower 9 through the heat medium water circulation heater 4. The generated water vapor, ammonia gas and carbon dioxide gas are first introduced into the washing tower 14. Most of the ammonia gas is removed in the washing tower 14, and then the water vapor is removed by cooling to avoid the occurrence of ammonium bicarbonate crystallization, thereby effectively avoiding pipeline blockage. Thus, the system failure rate is reduced, and the maintenance frequency and cost are also significantly reduced. The cost of ammonium bicarbonate desorption and regeneration is also reduced. In addition, after most of the ammonia gas is removed in the washing tower 14, the purity of carbon dioxide separation and purification can reach more than 99.5%, and the purification effect is effectively improved.
[0027] The above has described in detail the embodiments of the utility model in conjunction with the accompanying drawings, but the utility model is not limited to the described embodiments. For those skilled in the art, without departing from the principle and spirit of the utility model, various changes, modifications, substitutions and variations made to these embodiments still fall within the protection scope of the utility model.
Claims
1. An ammonium bicarbonate desorption and regeneration system, comprising a circulation pump (3), a heat medium water circulation heater (4), a lean and rich liquid heat exchanger (5), a lean liquid pump (8), an ammonium bicarbonate desorption tower (9), a washing tower (14), a circulation water pump (12), a gas-liquid separator (16), a condenser (17), a dryer (18), a compressor (19), and a storage tank (20); characterized in that: The washing tower (14) is provided with an absorption spray layer (10), a packing layer (13) is provided in the washing tower (14) and located above the absorption spray layer (10), and a demisting spray layer (15) is provided in the washing tower (14) and located above the packing layer (13); an ammonia-rich water outlet (11) is provided at the lower end of the washing tower (14); the liquid outlet of the circulating water pump (12) is connected to the liquid inlet of the absorption spray layer (10), and the circulating water pump (12) The suction end of the lean liquid pump (8) is connected to the lower end of the inner cavity of the washing tower (14); the suction end of the lean liquid pump (8) is connected to the lower end of the inner cavity of the ammonium bicarbonate desorption tower (9), and the liquid outlet end is connected to the inlet of the second fluid channel of the lean-rich liquid heat exchanger (5); the outlet of the second fluid channel of the lean-rich liquid heat exchanger (5) is used to discharge the ammonium bicarbonate lean liquid (7); the outlet of the first fluid channel of the lean-rich liquid heat exchanger (5) is connected to the inner cavity of the ammonium bicarbonate desorption tower (9); the lean-rich liquid The inlet of the first fluid channel of the heat exchanger (5) is used to introduce ammonium bicarbonate rich liquid (6); the liquid suction end of the circulation pump (3) is communicated with the lower part of the inner cavity of the ammonium bicarbonate desorption tower (9), and the liquid discharge end is communicated with the inlet of the first fluid channel of the heat medium water circulation heater (4), and the outlet of the first fluid channel of the heat medium water circulation heater (4) is communicated with the upper part of the inner cavity of the ammonium bicarbonate desorption tower (9); the inlet of the second fluid channel of the heat medium water circulation heater (4) is used to introduce the high-temperature flue gas (1) before desulfurization, and the outlet is used to discharge the flue gas (2) after heat exchange; the exhaust end of the washing tower (14) is communicated with the inlet of the condenser (17), the outlet of the condenser (17) is communicated with the inlet of the gas-liquid separator (16), the exhaust end of the gas-liquid separator (16) is communicated with the inlet of the dryer (18), the outlet of the dryer (18) is communicated with the inlet of the compressor (19), and the inlet of the compressor (19) is communicated with the inlet of the storage (20).
2. The ammonium bicarbonate desorption and regeneration system according to claim 1, characterized in that: The heat medium water circulation heater uses high-temperature flue gas before desulfurization as a heat source.
3. The ammonium bicarbonate desorption and regeneration system according to claim 1, characterized in that: The desorption regeneration gas is first passed through a scrubbing tower to remove ammonia from the gas before condensation.
4. The ammonium bicarbonate desorption and regeneration system according to claim 1, characterized in that: The lean-rich liquid heat exchanger (5) is a plate-type heat exchanger.
5. The ammonium bicarbonate desorption and regeneration system according to claim 1, characterized in that: The condenser (17) is an air natural convection condenser.