A waste heat recovery system for ammonia desulfurization

Abstract

This utility model discloses a waste heat recovery system for ammonia desulfurization, belonging to the field of waste heat recovery technology. The desulfurization tower includes an adsorption spray chamber. The slurry in the adsorption spray chamber is flashed through a first flash unit to generate exhaust steam. The exhaust steam provides a heat source for a first heat exchange unit. The slurry after flashing through the first flash unit is transported to an ammonia storage unit through a first channel. The ammonia storage unit is connected to the adsorption spray chamber through a pipeline. This application utilizes the exhaust steam generated by the flash slurry in the first flash unit as a heat source for the first heat exchange unit to recover waste heat from the outside. The addition of a second flash unit further improves the heat recovery efficiency. The system uses an auxiliary spray chamber to adsorb excess ammonia, preventing ammonia escape and pollution. The oxidizing gas exhaust pipeline prevents the accumulation of crystals in the concentrated spray chamber, ensuring efficient media discharge. The coordinated operation of each unit improves desulfurization efficiency, system stability, and environmental friendliness, while reducing energy waste and operating costs.

Description

Technical Field

[0001] This utility model belongs to the field of waste heat utilization technology, and in particular to a waste heat utilization system for ammonia desulfurization. Background Technology

[0002] In ammonia-based desulfurization processes, a large amount of slurry and flue gas containing waste heat is generated. Traditional systems often fail to effectively recover and utilize this waste heat, resulting in energy waste and increased system operating costs. Furthermore, in existing desulfurization tower structures, the concentration spray chamber may experience crystal accumulation during solution concentration, affecting media discharge efficiency. Ammonia escape also easily leads to air pollution, indicating insufficient environmental friendliness. Simultaneously, the collaborative working capacity of the various units within the system is limited, making it difficult to achieve efficient and unified desulfurization, solution concentration, and waste heat recovery. Therefore, there is an urgent need for an ammonia-based desulfurization waste heat utilization system that can improve energy utilization, reduce ammonia escape, and optimize system operational stability. Utility Model Content

[0003] Purpose of the utility model: To provide a waste heat utilization system for ammonia desulfurization to solve the above-mentioned problems existing in the prior art.

[0004] Technical solution: A waste heat utilization system for ammonia desulfurization includes: a desulfurization tower, the desulfurization tower including an adsorption spray chamber, the slurry in the adsorption spray chamber is flashed by a first flash unit to generate exhaust steam, the exhaust steam provides a heat source for a first heat exchange unit, the slurry after flashing by the first flash unit is transported to an ammonia water storage unit through a first channel, and the ammonia water storage unit is connected to the adsorption spray chamber through a pipeline.

[0005] Furthermore, the desulfurization tower also includes a concentration spray chamber, through which flue gas enters the adsorption spray chamber, and the adsorption spray chamber is selectively connected to the concentration spray chamber through a return liquid pipeline.

[0006] Furthermore, a circulating spray unit is provided on the concentrated spray chamber.

[0007] Furthermore, the circulating spray unit includes: a circulating pipeline, one end of which is connected to the bottom of the concentrated spray chamber, and the other end is connected to the spray head inside the circulating spray unit, and a first circulating pump is provided on the circulating pipeline.

[0008] Furthermore, the ammonia storage unit is equipped with an ammonia replenishment pipeline.

[0009] Furthermore, the ammonia storage unit is equipped with an oxidation gas inlet pipe and an oxidation gas exhaust pipe, and the ammonia storage unit is connected to the concentration spray chamber through the oxidation gas exhaust pipe.

[0010] Furthermore, it also includes a concentrated medium outlet connected to the concentrated spray chamber.

[0011] Furthermore, it also includes an auxiliary spray chamber to prevent ammonia escape. After the flue gas passes through the adsorption spray chamber, it enters the auxiliary spray chamber, and the auxiliary spray chamber is equipped with an auxiliary spray unit.

[0012] Furthermore, the auxiliary spraying unit includes a water storage unit, which is connected to the nozzle and the bottom of the auxiliary spraying chamber through connecting pipes. A second circulation pump is provided on the connecting pipes, and a water replenishment pipe is provided on the water storage unit.

[0013] Furthermore, it also includes a second flash evaporation unit, in which the medium in the concentration spray chamber is flashed by the exhaust steam generated by the second flash evaporation unit, and the exhaust steam provides a heat source for the second heat exchange unit through the second channel.

[0014] Beneficial effects:

[0015] This application utilizes the exhaust steam generated from the flash evaporation of the slurry in the first flash evaporation unit as a heat source in the first heat exchange unit, providing it as waste heat for external use. Simultaneously, the addition of a second flash evaporation unit further enhances heat recovery efficiency. The system prevents ammonia escape and contamination by adsorbing excess ammonia in the auxiliary spray chamber, and the oxidizing gas exhaust pipe prevents crystal buildup in the concentrated spray chamber, ensuring efficient media discharge. The coordinated operation of each unit improves desulfurization efficiency, system stability, and environmental friendliness, while reducing energy waste and operating costs. Attached Figure Description

[0016] Figure 1 This is a system diagram of Embodiment 1 of this utility model;

[0017] Figure 2 This is a system diagram of Embodiment 2 of this utility model.

[0018] The attached diagram is labeled as follows: desulfurization tower 100, adsorption spray chamber 110, concentration spray chamber 120, return liquid pipeline 130, auxiliary spray chamber 140, first flash evaporation unit 200, first heat exchange unit 300, ammonia storage unit 400, circulating spray unit 500, circulating pipeline 510, first circulating pump 520, ammonia replenishment pipeline 600, oxidant gas inlet pipeline 700, oxidant gas exhaust pipeline 800, concentrated medium outlet 900, auxiliary spray unit 1000, water storage unit 1010, connecting pipeline 1020, water replenishment pipeline 1030, second circulating pump 1040, second flash evaporation unit 1100, and second heat exchange unit 1200. Detailed Implementation

[0019] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid confusion with the present invention.

[0020] Example 1: Combined with Appendix Figure 1 Description: An ammonia-based desulfurization waste heat utilization system includes a desulfurization tower 100, which includes an adsorption spray chamber 110. The slurry in the adsorption spray chamber 110 is flashed by a first flash unit 200 to generate exhaust steam, which provides a heat source for a first heat exchange unit 300. The slurry after flashing by the first flash unit 200 is transported to an ammonia water storage unit 400 through a first channel. The ammonia water storage unit 400 is connected to the adsorption spray chamber 110 via a pipeline. The desulfurization tower 100 also includes a concentration spray chamber 120. Flue gas enters the adsorption spray chamber 110 after passing through the concentration spray chamber 120. The adsorption spray chamber 110 is selectively connected to the concentration spray chamber 120 via a return liquid pipeline 130. A circulating spray unit 500 is installed on the concentration spray chamber 120. The circulating spray unit 500 includes: a circulating pipeline 510, one end of which is connected to the bottom of the concentrating spray chamber 120, and the other end of which is connected to a spray head inside the circulating spray unit 500. A first circulating pump 520 is installed on the circulating pipeline 510. An ammonia water storage unit 400 is provided with an ammonia water replenishment pipeline 600. An oxidizing gas inlet pipeline 700 and an oxidizing gas exhaust pipeline 800 are provided on the ammonia water storage unit 400, and the ammonia water storage unit 400 is connected to the concentrating spray chamber 120 through the oxidizing gas exhaust pipeline 800. It also includes a concentrated medium outlet 900 connected to the concentrating spray chamber 120. It also includes an auxiliary spray chamber 140 to prevent ammonia escape. Flue gas enters the auxiliary spray chamber 140 after passing through the adsorption spray chamber 110, and an auxiliary spray unit 1000 is installed on the auxiliary spray chamber 140. The auxiliary spray unit 1000 includes a water storage unit 1010, which is connected to the nozzle and bottom of the auxiliary spray chamber 140 through a connecting pipe 1020. A second circulation pump 1040 is provided on the connecting pipe 1020, and a water replenishment pipe 1030 is provided on the water storage unit 1010.

[0021] The desulfurization tower 100 includes a raw flue gas inlet pipe and a clean flue gas outlet pipe. The bottom of the auxiliary spray chamber 140 is equipped with a drain outlet for controlling the liquid level and concentration. The oxidizing gas exhaust pipe 800 transports unreacted gas from the ammonia storage unit 400 to the bottom of the concentration spray chamber 120 for further reaction and to prevent crystal accumulation in the concentration spray chamber 120, which would affect the medium discharge efficiency. The first flash evaporation unit 200 and the first heat exchange unit 300 can be integrated or separate. The first heat exchange unit 300 contains heat exchange tubes containing the medium to be heated. The first heat exchange unit 300 also includes a cooling water outlet pipe and a vacuum pipe for evacuation. The first flash evaporation unit 200 contains a demister. The return liquid pipe 130 controls the liquid level in the adsorption spray chamber 110 and is equipped with a valve. The ammonia storage unit 400 is connected to the adsorption spray chamber 110 via a pipeline, specifically connected to the nozzles within the adsorption spray chamber 110. A circulation pump is installed on the connecting pipeline for spraying ammonia water to perform ammonia-based desulfurization of the flue gas. The adsorption spray chamber 110 is the main desulfurization chamber for the flue gas. The main function of the concentration spray chamber 120 is to perform the first heat exchange after the dry flue gas is sprayed, turning the dry flue gas into saturated wet flue gas, thereby concentrating the solution in the concentration spray chamber 120. The auxiliary spray chamber 140 mainly functions to prevent excessive ammonia in the flue gas from being discharged into the atmosphere with the flue gas in the adsorption spray chamber 110. Ammonia is adsorbed through spray washing. When the concentration is too high, it is discharged through the drain outlet. At the same time, the water replenishment pipeline 1030 replenishes fresh water to ensure stable circulation. The medium in the ammonia storage unit 400 is an ammonium sulfite solution, which is oxidized by oxygen in the oxidizing gas inlet pipeline 700 to form ammonium sulfate.

[0022] The concentration spray chamber 120 of the desulfurization tower 100 of this application performs the first heat exchange on the flue gas, turning the dry flue gas into saturated wet flue gas while concentrating the solution in the chamber to increase the solution concentration. The adsorption spray chamber 110, as the main desulfurization chamber, works in conjunction with the ammonia water storage unit 400 to deliver ammonia water for desulfurization, which can improve the desulfurization efficiency. The first flash evaporation unit 200 flashes the slurry to generate exhaust steam, which provides a heat source for the first heat exchange unit 300, realizing waste heat recovery and utilization, and improving the system's energy utilization rate. The auxiliary spray chamber 140 adsorbs excess ammonia through the auxiliary spray unit 1000's spray water washing, preventing ammonia from escaping and polluting the atmosphere, while maintaining stable circulation through the drain outlet and water supply pipeline 1030. The oxidizing gas inlet pipe 700 oxidizes ammonium sulfite into ammonium sulfate, and the oxidizing gas exhaust pipe 800 transports unreacted gas to the concentration spray chamber 120 to prevent the accumulation of crystals. The return liquid pipe 130 controls the liquid level in the adsorption spray chamber 110. All units work together to improve the system's stability and environmental friendliness.

[0023] Example 2, based on Example 1, combined with Appendix Figure 2 The description also includes a second flash evaporation unit 1100, in which the medium in the concentration spray chamber 120 is flashed by the exhaust steam generated by the second flash evaporation unit 1100, and the exhaust steam provides a heat source for the second heat exchange unit 1200 through the second channel.

[0024] The second flash evaporation unit 1100 and the second channel are the same as the structure and connection method of the second heat exchange unit 1200 and the first flash evaporation unit 200 and the first heat exchange unit 300, and are used to extract heat from the medium in the concentration spray chamber 120.

[0025] This application adds a second flash evaporation unit 1100 and a second heat exchange unit 1200 to the first embodiment to extract heat from the medium in the concentration spray chamber 120, further recovering waste heat from the system and increasing heat recovery pathways to improve energy utilization efficiency. Since the structure and connection method of the second flash evaporation unit 1100 and the second heat exchange unit 1200 are the same as those of the first flash evaporation unit 200 and the first heat exchange unit 300, system reliability and reproducibility can be guaranteed, facilitating equipment design, manufacturing, and maintenance. Through two flash heat exchanges, the heat from the desulfurization process is more fully utilized, reducing energy waste. Simultaneously, extracting heat from the medium in the concentration spray chamber 120 helps maintain its concentration stability, further improving concentration efficiency, making the system more efficient and energy-saving in desulfurization, concentration, and waste heat utilization.

[0026] Work process:

[0027] Flue gas enters the concentration spray chamber 120 of the desulfurization tower 100 through the original flue gas inlet pipe. After being sprayed by the circulating spray unit 500, it completes the first heat exchange, turning the dry flue gas into saturated wet flue gas. At the same time, the solution in the concentration spray chamber 120 is concentrated, and the concentrated medium that meets the standard is discharged through the concentrated medium outlet 900. The flue gas then enters the adsorption spray chamber 110, where the ammonia water storage unit 400 supplies ammonia water to its nozzles through pipelines and a circulating pump for ammonia-based desulfurization of the flue gas. The slurry in the adsorption spray chamber 110 enters the first flash evaporation unit 200 through the first channel for flash evaporation, generating exhaust steam to provide a heat source for the first heat exchange unit 300. The flash-evaporated slurry returns to the ammonia water storage unit 400 through pipelines. The ammonium sulfite solution in the ammonia water storage unit 400 is oxidized to ammonium sulfate by introducing oxygen through the oxidation gas inlet pipe 700. Unreacted gas is sent to the bottom of the concentration spray chamber 120 through the oxidation gas exhaust pipe 800 to prevent crystal accumulation. The desulfurized flue gas enters the auxiliary spray chamber 140. The water storage unit 1010 of the auxiliary spray unit 1000 is sprayed with water through the connecting pipe 1020 and the circulating pump, adsorbing excess ammonia. When the concentration is too high, it is discharged from the drain outlet, and fresh water is replenished through the water supply pipe 1030. In Example 2, the medium in the concentration spray chamber 120 is flash-evaporated by the second flash unit 1100 to generate exhaust steam, which is then used to heat the second heat exchange unit 1200 through the second channel. Its structure and connection method are the same as those of the first flash unit 200 and the first heat exchange unit 300. The clean flue gas is finally discharged through the clean flue gas discharge pipe.

[0028] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and all such equivalent transformations fall within the protection scope of the present invention.

Claims

1. An ammonia desulfurization waste heat utilization system, characterized in that, include: The desulfurization tower (100) includes an adsorption spray chamber (110). The slurry in the adsorption spray chamber (110) is flashed by a first flash unit (200) to generate exhaust steam. The exhaust steam provides a heat source for a first heat exchange unit (300). The slurry after flashing by the first flash unit (200) is transported to an ammonia storage unit (400) through a first channel. The ammonia storage unit (400) is connected to the adsorption spray chamber (110) through a pipeline.

2. The ammonia desulfurization waste heat utilization system according to claim 1, characterized in that, The desulfurization tower (100) also includes a concentration spray chamber (120). After passing through the concentration spray chamber (120), the flue gas enters the adsorption spray chamber (110). The adsorption spray chamber (110) is selectively connected to the concentration spray chamber (120) through a return liquid pipeline (130).

3. The ammonia desulfurization waste heat utilization system according to claim 2, characterized in that, The concentrated spray chamber (120) is equipped with a circulating spray unit (500).

4. The ammonia desulfurization waste heat utilization system according to claim 3, characterized in that, The circulating spray unit (500) includes: a circulating pipeline (510), one end of which is connected to the bottom of the concentrated spray chamber (120), and the other end is connected to the nozzle inside the circulating spray unit (500). A first circulating pump (520) is provided on the circulating pipeline (510).

5. The ammonia desulfurization waste heat utilization system according to claim 1, characterized in that, The ammonia storage unit (400) is equipped with an ammonia replenishment pipeline (600).

6. The ammonia desulfurization waste heat utilization system according to claim 2, characterized in that, The ammonia storage unit (400) is provided with an oxidation gas inlet pipe (700) and an oxidation gas exhaust pipe (800). The ammonia storage unit (400) is connected to the concentration spray chamber (120) through the oxidation gas exhaust pipe (800).

7. The ammonia desulfurization waste heat utilization system according to claim 2, characterized in that, It also includes a concentrated medium outlet (900) connected to the concentrated spray chamber (120).

8. The ammonia desulfurization waste heat utilization system according to claim 2, characterized in that, It also includes an auxiliary spray chamber (140) to prevent ammonia escape. After the flue gas passes through the adsorption spray chamber (110), it enters the auxiliary spray chamber (140). An auxiliary spray unit (1000) is provided on the auxiliary spray chamber (140).

9. The ammonia-based desulfurization waste heat utilization system according to claim 8, characterized in that, The auxiliary spray unit (1000) includes a water storage unit (1010), which is connected to the nozzle and bottom of the auxiliary spray chamber (140) through a connecting pipe (1020). A second circulation pump (1040) is provided on the connecting pipe (1020), and a water replenishment pipe (1030) is provided on the water storage unit (1010).

10. The ammonia desulfurization waste heat utilization system according to claim 2, characterized in that, It also includes a second flash evaporation unit (1100), in which the medium in the concentration spray chamber (120) generates exhaust steam through the flash evaporation of the second flash evaporation unit (1100), and the exhaust steam provides a heat source for the second heat exchange unit (1200) through the second channel.

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