Flue gas desulfurization and denitrification purification treatment system

Abstract

The application discloses a flue gas desulfurization and denitrification purification treatment system, which comprises an adsorption tower, a regeneration tower and a reaction tower. The adsorption tower is provided with an adsorbent, so that the flue gas enters the adsorption tower and the sulfur oxides and nitrogen oxides in the flue gas are removed by the adsorbent. The regeneration tower is connected with the adsorption tower, so that the saturated adsorbent enters the regeneration tower and is desorbed and regenerated. The reaction tower is connected with the regeneration tower, so that the regenerated gas desorbed and regenerated by the regeneration tower enters the reaction tower to produce salt, and part of the tail gas produced by the reaction tower enters the regeneration tower to carry the regenerated gas and flow out of the regeneration tower. In the application, part of the salt production tail gas is used as protective gas to replace nitrogen, so that the use amount of nitrogen in the regeneration tower is reduced, and the operation cost and initial investment of the system are reduced. In addition, the salt production tail gas is rich in pollutants, so that the concentration of pollutants in the regenerated gas can be effectively increased, and the salt production reaction in the subsequent reaction tower is facilitated.

Description

Technical Field

[0001] This invention relates to the field of flue gas purification technology, and in particular to a flue gas desulfurization and denitrification purification system. Background Technology

[0002] With increasingly stringent environmental policies, higher requirements have been placed on the emission control of sulfur oxides (SOx) and nitrogen oxides (NOx) in flue gas. Activated coke / carbon desulfurization and denitrification technology, as a highly efficient flue gas purification method, has been widely used in many industrial fields. However, in the activated coke / carbon desulfurization and denitrification process, the adsorbent saturated in the adsorption tower needs to be transported to a regeneration tower for regeneration.

[0003] In related technologies, the regeneration tower operates at a high temperature (approximately 350°C), which can easily lead to spontaneous combustion of the adsorbent. To prevent this, nitrogen gas is introduced into the regeneration tower for sealing, isolating it from air. Simultaneously, nitrogen acts as a carrier gas, promptly carrying away the pollutant-rich gases released during regeneration. However, the regeneration process requires a large amount of nitrogen for both sealing and carrier gas functions, increasing the system's operating costs and initial investment. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention propose a flue gas desulfurization and denitrification purification system to solve the problem of high cost in related technologies.

[0006] The flue gas desulfurization and denitrification purification system of this invention includes:

[0007] An adsorption tower containing an adsorbent is provided so that flue gas enters the adsorption tower and the adsorbent adsorbs and removes sulfur oxides and nitrogen oxides from the flue gas.

[0008] A regeneration tower is connected to the adsorption tower so that the adsorbent saturated with adsorption can enter the regeneration tower for desorption and regeneration.

[0009] A reaction tower is connected to the regeneration tower so that the regeneration gas generated by the regeneration tower enters the reaction tower to produce salt, and part of the tail gas generated by the salt production in the reaction tower enters the regeneration tower to carry the regeneration gas out of the regeneration tower.

[0010] The flue gas desulfurization and denitrification purification system of this invention uses a portion of the salt production tail gas as a protective gas to replace nitrogen, thereby reducing the amount of nitrogen used in the regeneration tower and lowering the system's operating costs and initial investment. Furthermore, the salt production tail gas is rich in pollutants, which can effectively increase the concentration of pollutants in the regeneration gas, thus benefiting the subsequent salt production reaction in the reaction tower.

[0011] In some embodiments, the regeneration tower has a regeneration gas outlet and a protective gas inlet. The regeneration gas outlet of the regeneration tower is connected to the inlet of the reaction tower via a pipeline so that the regeneration gas is transported into the reaction tower via the pipeline. The outlet of the reaction tower is connected to the protective gas inlet of the regeneration tower via a pipeline so that the salt production tail gas is transported into the regeneration tower via the pipeline.

[0012] In some embodiments, the regeneration gas outlet of the regeneration tower is located in the middle of the regeneration tower.

[0013] In some embodiments, the protective gas inlet of the regeneration tower includes a first protective gas inlet and a second protective gas inlet. The first protective gas inlet of the regeneration tower is connected to the outlet of the reaction tower via a pipeline, and the second protective gas inlet of the regeneration tower is connected to a nitrogen source via a pipeline.

[0014] In some embodiments, the first protective gas inlet of the regeneration tower is located at the upper part of the regeneration tower, and the second protective gas inlet of the regeneration tower is located at the lower part of the regeneration tower.

[0015] In some embodiments, a scrubbing tower is further included, the inlet of which is connected to the regeneration gas outlet of the regeneration tower via a pipeline, and the outlet of which is connected to the inlet of the reaction tower via a pipeline, so that the regeneration gas is scrubbed to remove dust before being sent into the reaction tower for salt production.

[0016] In some embodiments, an induced draft fan is provided on the pipeline between the regeneration gas outlet of the regeneration tower and the inlet of the scrubbing tower.

[0017] In some embodiments, the outlet of the reaction tower is also connected to the boiler via a pipeline, so that a portion of the salt production tail gas is sent into the regeneration tower, and another portion of the salt production tail gas is returned to the furnace for combustion.

[0018] In some embodiments, both the adsorption tower and the regeneration tower have an adsorbent inlet and an adsorbent outlet. The adsorbent outlet of the adsorption tower is connected to the adsorbent inlet of the regeneration tower via a pipeline, so that the adsorbent saturated with adsorption is transported to the regeneration tower for desorption and regeneration. The adsorbent outlet of the regeneration tower is connected to the adsorbent inlet of the adsorption tower via a pipeline, so that the desorbed and regenerated adsorbent is transported back to the adsorption tower to adsorb flue gas.

[0019] In some embodiments, the environment for flue gas adsorption and purification in the adsorption tower is below zero degrees Celsius. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the flue gas desulfurization and denitrification purification system according to an embodiment of the present invention.

[0021] Figure label:

[0022] 1-Adsorption tower, 2-Regeneration tower, 201-Regeneration gas outlet, 202-First protective gas inlet, 203-Second protective gas inlet, 3-Reaction tower, 4-Scrubbing tower, 5-Exhaust fan. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] The flue gas desulfurization and denitrification purification system of the present invention is described below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, the flue gas desulfurization and denitrification purification system of this embodiment includes: an adsorption tower 1, a regeneration tower 2, and a reaction tower 3.

[0026] The adsorption tower 1 contains an adsorbent. The flue gas generated by boiler combustion enters the adsorption tower 1, and the adsorbent adsorbs and removes sulfur oxides and nitrogen oxides from the flue gas, thereby achieving the purpose of flue gas purification.

[0027] It should be noted that the flue gas adsorption and purification environment in adsorption tower 1 is below zero degrees Celsius. In the low-temperature environment of the sub-zero temperature zone, nitrogen oxides in the flue gas undergo low-temperature oxidation adsorption on the surface of adsorbents such as activated carbon, oxidizing the difficult-to-adsorb nitric oxide gas into easily adsorbable nitrogen dioxide gas, achieving a several hundred-fold increase in adsorption capacity. In addition, the adsorption capacity of components such as sulfur dioxide, carbon dioxide, and heavy metals is also increased several times in the low-temperature environment.

[0028] For example, before entering adsorption tower 1, the flue gas is first cooled by spraying in a spray tower to cool it to the sub-zero temperature range.

[0029] Regeneration tower 2 is connected to adsorption tower 1. When the adsorbent adsorbs the flue gas to the point of saturation, the saturated adsorbent enters regeneration tower 2 for desorption and regeneration.

[0030] Reaction tower 3 is connected to regeneration tower 2. The regenerated gas from regeneration tower 2 enters reaction tower 3 for salt production. Reaction tower 3 is the core equipment in the salt production workshop. The regenerated gas is used to produce products such as sodium sulfate and sodium metabisulfite, and to recover sulfur resources from the rich gas.

[0031] A stream of tail gas produced by salt production in reaction tower 3 is introduced into regeneration tower 2 to replace nitrogen gas for sealing and as a carrier gas in regeneration tower 2.

[0032] Therefore, the flue gas desulfurization and denitrification purification system of this embodiment uses part of the salt production tail gas as a protective gas to replace nitrogen, thereby reducing the nitrogen consumption in regeneration tower 2 by 50%, lowering the system's operating costs and initial investment. Furthermore, the salt production tail gas is rich in pollutants, which can effectively increase the concentration of pollutants in the regeneration gas, benefiting the subsequent salt production reaction in reaction tower 3.

[0033] In some embodiments, such as Figure 1 As shown, regeneration tower 2 has a regeneration gas outlet 201 and a protective gas inlet. The regeneration gas outlet 201 of regeneration tower 2 is connected to the inlet of reaction tower 3 via a pipeline, so that the regeneration gas can be transported into reaction tower 3 through the pipeline. The outlet of reaction tower 3 is connected to the protective gas inlet of regeneration tower 2 via a pipeline, so that the salt production tail gas can be transported into regeneration tower 2 through the pipeline.

[0034] Understandably, the salt production tail gas, rich in moisture, can be used as a protective gas to fill regeneration tower 2 to prevent the adsorbent from spontaneously combusting, and at the same time, it can be used as a carrier gas to carry away the pollutants released during the regeneration process.

[0035] The tail gas from salt production is piped to the protective gas inlet of regeneration tower 2, where it is introduced into the tower, mixed with the regeneration gas, and then discharged together into reaction tower 3. The entire process ensures a closed-loop system, reduces gas emissions, and improves resource utilization.

[0036] Optionally, such as Figure 1 As shown, the regeneration gas outlet 201 of the regeneration tower 2 is located in the middle of the regeneration tower 2.

[0037] It should be noted that the regeneration tower 2 is divided into a preheating section, a heating section, and a cooling section from top to bottom. The middle section of the regeneration tower 2 is mainly used for heating and desorbing the adsorbent, meaning that most of the regeneration gas is generated in the middle section of the regeneration tower 2. Therefore, the regeneration gas outlet 201 is located in the middle of the regeneration tower 2 to facilitate the regeneration gas flow out of the regeneration tower 2.

[0038] In some embodiments, such as Figure 1 As shown, the protective gas inlet of regeneration tower 2 includes a first protective gas inlet 202 and a second protective gas inlet 203. The first protective gas inlet 202 of regeneration tower 2 is connected to the outlet of reaction tower 3 via a pipeline, and the second protective gas inlet 203 of regeneration tower 2 is connected to a nitrogen source via a pipeline.

[0039] Understandably, the components of the salt production tail gas may include water vapor, salt spray, potentially organic matter, and small amounts of unreacted chemicals. These components could affect the reaction environment within regeneration tower 2. Nitrogen, as an inert gas, can provide a more stable gaseous environment, facilitating precise control of the regeneration process.

[0040] While the inert gases in the salt production tail gas offer some protection, they are insufficient to completely isolate the adsorbent from oxygen and prevent spontaneous combustion. The addition of nitrogen provides extra protection, ensuring that the adsorbent does not spontaneously combust at high temperatures.

[0041] The flow rate and composition of the salt production tail gas may fluctuate depending on the production process, which may affect the operational stability of regeneration tower 2. The addition of nitrogen can help maintain a relatively stable environment.

[0042] Furthermore, such as Figure 1 As shown, the first protective gas inlet 202 of the regeneration tower 2 is located at the upper part of the regeneration tower 2, and the second protective gas inlet 203 of the regeneration tower 2 is located at the lower part of the regeneration tower 2. The salt production tail gas enters the regeneration tower 2 from the upper part and flows to the middle part of the regeneration tower 2, while the nitrogen gas enters the regeneration tower 2 from the lower part and flows to the middle part of the regeneration tower 2.

[0043] Understandably, the lower part of regeneration tower 2 contains the regenerated adsorbent. Since the regenerated gas used for salt production recovers sulfur resources, nitrogen oxides still exist in the regenerated gas. Therefore, it is necessary to prevent the salt production tail gas from entering from the lower part and causing adsorbent contamination. The upper adsorbent is already saturated, so this problem does not exist, thus improving the rationality of reusing the salt production tail gas.

[0044] In some embodiments, such as Figure 1 As shown, a scrubbing tower 4 is also included between the regeneration tower 2 and the reaction tower 3. The inlet of the scrubbing tower 4 is connected to the regeneration gas outlet 201 of the regeneration tower 2 via a pipeline, and the outlet of the scrubbing tower 4 is connected to the inlet of the reaction tower 3 via a pipeline, so that the regeneration gas is washed by the scrubbing tower 4 to remove dust before being sent into the reaction tower 3 for salt production.

[0045] Understandably, the purpose of washing the regenerated gas before salt production is to ensure the smooth progress of the salt production process and improve product quality.

[0046] Regenerated gas contains dust, unreacted chemicals, and other impurities. Washing can remove these impurities, preventing them from forming precipitates or affecting the purity and quality of the salt during production.

[0047] Furthermore, dust and other solid particles can clog or wear down pipes, pumps, and other equipment, leading to system instability or even equipment damage. Washing treatments can reduce the amount of these particles and extend equipment life.

[0048] In some embodiments, an induced draft fan 5 is provided on the pipeline between the regeneration gas outlet 201 of the regeneration tower 2 and the inlet of the scrubbing tower 4.

[0049] Understandably, the induced draft fan 5 helps overcome resistance in the system and increases the gas flow rate, thereby improving the flow efficiency of regenerated gas from regeneration tower 2 to scrubbing tower 4. Through the suction action of the induced draft fan 5, the pressure difference between regeneration tower 2 and scrubbing tower 4 can be adjusted to ensure the system operates at an appropriate pressure, avoiding equipment damage or operational instability caused by excessively high or low pressure.

[0050] In some embodiments, such as Figure 1 As shown, the outlet of the reaction tower 3 is also connected to the boiler (not shown in the figure) via a pipeline, so that a portion of the salt production tail gas is sent into the regeneration tower 2, and the other portion of the salt production tail gas is returned to the furnace for combustion.

[0051] It is important to note that nitrogen oxides in salt production exhaust gas can act as an oxidant, contributing to complete combustion in the boiler and thus improving its combustion efficiency. Therefore, returning the nitrogen oxides in the salt production exhaust gas to the boiler for combustion achieves final treatment and resource utilization of nitrogen oxides.

[0052] In some embodiments, such as Figure 1 As shown, both adsorption tower 1 and regeneration tower 2 have adsorbent inlets and adsorbent outlets.

[0053] The adsorbent outlet of adsorption tower 1 is connected to the adsorbent inlet of regeneration tower 2 via a pipeline, so that the saturated adsorbent is transported to regeneration tower 2 for desorption and regeneration. The adsorbent outlet of regeneration tower 2 is connected to the adsorbent inlet of adsorption tower 1 via a pipeline, so that the desorbed and regenerated adsorbent is transported back to adsorption tower 1 to adsorb flue gas.

[0054] Understandably, after the adsorbent adsorbs pollutants in adsorption tower 1, it can be regenerated in regeneration tower 2 by circulating the adsorbent, thus restoring its adsorption capacity. This recycling ensures that the adsorbent always maintains a high adsorption efficiency and extends its service life.

[0055] The recirculation of adsorbents means that the same adsorbent can be reused, reducing adsorbent consumption, lowering costs, and benefiting the environment. Through the regeneration process, pollutants in the adsorbent are desorbed and transferred to the regenerated rich gas, which reduces the generation of solid waste and lowers the cost of waste treatment.

[0056] A circulating adsorbent provides a continuous and stable adsorption-regeneration process, helping to maintain the stability of system operation. By controlling the flow rate and residence time of the adsorbent between adsorption tower 1 and regeneration tower 2, the system's operating parameters can be flexibly adjusted to adapt to different operating conditions and loads.

[0057] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0058] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0059] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0060] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0061] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0062] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A flue gas desulfurization and denitrification purification system, characterized in that, include: An adsorption tower containing an adsorbent is provided so that flue gas enters the adsorption tower and the adsorbent adsorbs and removes sulfur oxides and nitrogen oxides from the flue gas. A regeneration tower is connected to the adsorption tower so that the adsorbent saturated with adsorption enters the regeneration tower for desorption and regeneration. The middle part of the regeneration tower is used to heat and desorb the adsorbent, and the desorbed and regenerated adsorbent is located in the lower part of the regeneration tower. A reaction tower is connected to a regeneration tower so that the regeneration gas generated by the regeneration tower enters the reaction tower to produce salt, and part of the tail gas generated by the salt production in the reaction tower enters the regeneration tower from the top to carry the regeneration gas out from the middle of the regeneration tower.

2. The flue gas desulfurization and denitrification purification system according to claim 1, characterized in that, The regeneration tower has a regeneration gas outlet and a protective gas inlet. The regeneration gas outlet of the regeneration tower is connected to the inlet of the reaction tower via a pipeline so that the regeneration gas can be transported into the reaction tower through the pipeline. The outlet of the reaction tower is connected to the protective gas inlet of the regeneration tower via a pipeline so that the salt production tail gas can be transported into the regeneration tower through the pipeline.

3. The flue gas desulfurization and denitrification purification system according to claim 2, characterized in that, The regenerated gas outlet of the regeneration tower is located in the middle of the regeneration tower.

4. The flue gas desulfurization and denitrification purification system according to claim 3, characterized in that, The protective gas inlet of the regeneration tower includes a first protective gas inlet and a second protective gas inlet. The first protective gas inlet of the regeneration tower is connected to the outlet of the reaction tower via a pipeline, and the second protective gas inlet of the regeneration tower is connected to a nitrogen source via a pipeline.

5. The flue gas desulfurization and denitrification purification system according to claim 4, characterized in that, The first protective gas inlet of the regeneration tower is located at the upper part of the regeneration tower, and the second protective gas inlet of the regeneration tower is located at the lower part of the regeneration tower.

6. The flue gas desulfurization and denitrification purification system according to claim 2, characterized in that, It also includes a scrubbing tower, the inlet of which is connected to the regeneration gas outlet of the regeneration tower via a pipeline, and the outlet of which is connected to the inlet of the reaction tower via a pipeline, so that the regeneration gas is scrubbed to remove dust before being sent into the reaction tower for salt production.

7. The flue gas desulfurization and denitrification purification system according to claim 6, characterized in that, An induced draft fan is installed on the pipeline between the regenerated gas outlet of the regeneration tower and the inlet of the scrubbing tower.

8. The flue gas desulfurization and denitrification purification system according to claim 4, characterized in that, The outlet of the reaction tower is also connected to the boiler via a pipeline, so that a portion of the salt production tail gas is sent into the regeneration tower, and the other portion of the salt production tail gas is returned to the furnace for combustion.

9. The flue gas desulfurization and denitrification purification system according to any one of claims 1-8, characterized in that, Both the adsorption tower and the regeneration tower have an adsorbent inlet and an adsorbent outlet. The adsorbent outlet of the adsorption tower is connected to the adsorbent inlet of the regeneration tower via a pipeline, so that the adsorbent that has been saturated with adsorption is transported to the regeneration tower for desorption and regeneration. The adsorbent outlet of the regeneration tower is connected to the adsorbent inlet of the adsorption tower via a pipeline, so that the desorbed and regenerated adsorbent is transported back to the adsorption tower to adsorb flue gas.

10. The flue gas desulfurization and denitrification purification system according to any one of claims 1-8, characterized in that, The environment inside the adsorption tower for flue gas adsorption and purification is below zero degrees Celsius.

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