Low-tower regenerated coal gas desulfurization process

Abstract

The invention relates to a low-tower regenerated coal gas desulfurization process, which comprises the following steps of: (1) feeding coke oven gas to be treated into the lower part of a primary desulfurization tower, enabling the coke oven gas to be in reverse contact with an absorption barren solution sprayed from the top of the primary desulfurization tower, absorbing H2S and HCN in coal gas by the absorption barren solution sprayed from the top of the primary desulfurization tower, the coal gas without H2S and HCN is discharged from the top of the first-stage desulfurization tower; (2) after being pressurized by a first-stage solution pump, rich liquid at the bottom of the first-stage desulfurization tower is mixed with compressed air through a premixing nozzle and then is fed into the bottom of a first-stage oxidation regeneration tower, the height of the first-stage oxidation regeneration tower is lower than that of the first-stage desulfurization tower, the rich liquid is oxidized and regenerated in the first-stage oxidation regeneration tower under the action of a catalyst, and the rich liquid is discharged from the bottom of the first-stage desulfurization tower; the regenerated barren solution is collected by a gas-liquid separator, the regenerated barren solution is pressurized by a barren solution pump and sent to the top of the first-stage desulfurization tower for cyclic spraying, and elemental sulfur generated by oxidation in the first-stage oxidation regeneration tower is subjected to air flotation to the upper part of the first-stage oxidation regeneration tower to form sulfur foam.

Description

Technical Field

[0001] The invention relates to a coal gas desulfurization process. Background Art

[0002] During the coking process, about 30%-35% of the sulfur in the coal is converted into sulfides such as hydrogen sulfide, and the rest of the sulfur enters the coke. Hydrogen sulfide, together with ammonia and hydrogen cyanide, forms impurities in coal gas. Their presence will not only seriously endanger people's health and corrode equipment, but also pollute the environment with combustion products; if used as synthesis gas, it will also cause catalyst poisoning; at the same time, various industrial furnaces and flame cutters also have certain requirements for the sulfur content in coke oven gas, so coke oven gas must be desulfurized and decyanated before use. Whether coke oven gas is used as fuel or as production raw material, it needs to be purified before use, mainly to remove H2S in the gas, to meet environmental protection and production requirements.

[0003] At present, the most widely used method for desulfurization and decyanation of industrial coke oven gas is wet oxidation. Most domestic coking plants generally use HPF desulfurization and decyanation process. HPF method is a desulfurization process developed by China. It has the characteristics of simple equipment, stable operation, high desulfurization efficiency, short process, low one-time investment and low operating cost. Therefore, it has been promoted and applied in many coking enterprises. Most domestic manufacturers use three-stage desulfurization process. The hydrogen sulfide index after the first-stage desulfurization tower is about 800mg / Nm³, the hydrogen sulfide index after the second-stage desulfurization tower is below 50mg / Nm³, and the hydrogen sulfide index after the third-stage desulfurization tower is below 20mg / Nm³.

[0004] After the primary desulfurization, the desulfurized liquid can be reused after regeneration in the regeneration tower. The rich liquid at the bottom of the primary desulfurization tower is sent to the regeneration tower, and under the catalytic action of the catalyst HPF, it is contacted with compressed air for oxidation and regeneration. In the existing coke oven gas desulfurization system, the amount of regeneration air required for regeneration is huge, and the height of the regeneration tower is higher than or equal to the height of the primary desulfurization tower. The temperature of the regenerated lean liquid is high, which affects the desulfurization effect in the primary desulfurization tower. Summary of the invention

[0005] In order to overcome the above-mentioned shortcomings of the existing coal gas desulfurization methods, the present invention provides a low-tower regeneration coal gas desulfurization process with less regeneration air consumption and better desulfurization effect.

[0006] The technical solution of the present invention to solve the technical problem is: a low-tower regeneration coal gas desulfurization process, comprising the following steps: ①. The coke oven gas to be treated is sent to the lower part of the primary desulfurization tower, and is reversely contacted with the lean absorption liquid sprayed from the top of the primary desulfurization tower. The lean absorption liquid sprayed from the top of the primary desulfurization tower absorbs H2S and HCN in the gas, and the gas with H2S and HCN removed is discharged from the top of the primary desulfurization tower; ②. The rich liquid at the bottom of the primary desulfurization tower is pressurized by the primary solution pump, mixed with compressed air through a premixing nozzle and sent to the bottom of the primary oxidation regeneration tower. The height of the primary oxidation regeneration tower is lower than that of the primary desulfurization tower. In the primary oxidation regeneration tower, air and rich liquid flow in the same direction and mix and contact. The rich liquid is oxidized and regenerated under the action of a catalyst using oxygen in the air. The regenerated lean liquid is collected by a gas-liquid separator and pressurized by a lean liquid pump and sent to the top of the primary desulfurization tower for circulating spraying. The elemental sulfur oxidized in the primary oxidation regeneration tower is floated to the upper part of the primary oxidation regeneration tower to form sulfur foam.

[0007] Furthermore, in step ②, the regenerated lean liquid is cooled in a cooler and then enters the top of the primary desulfurization tower again for recycling.

[0008] Furthermore, the premixing nozzle is vertically arranged at the bottom of the regeneration tower, and the premixing nozzle has a vertically arranged premixing chamber, and the premixing chamber extends upward to the upper end surface of the premixing nozzle to form an upward spraying port, and the rich liquid and compressed air mixed by the premixing nozzle are sprayed out from the spraying port; The premixing nozzle is also provided with a compressed air inlet and a rich liquid inlet, both of which are connected to the premixing chamber, the compressed air inlet is connected to an air compressor to pump in compressed air, and the rich liquid inlet is connected to the rich liquid outlet at the bottom of the primary desulfurization tower, and the rich liquid at the bottom of the primary desulfurization tower enters the premixing nozzle through the rich liquid inlet.

[0009] Furthermore, the premixing chamber extends downward to the lower end surface of the premixing nozzle to form a rich liquid inlet.

[0010] Furthermore, the premixing nozzle is provided with an inclined channel which is connected to the premixing chamber and is inclined from top to bottom to outside. The inclined channel is also provided with a transversely arranged air intake channel which is connected to the inclined channel. The end of the air intake channel forms the compressed air inlet.

[0011] Furthermore, a steam inlet is formed at the end of the inclined channel, and when a blockage is formed in the premixing nozzle, steam is passed into the inclined channel through the steam inlet to clear the blockage.

[0012] Furthermore, a support frame is provided on the premixing nozzle, the inclined channel is supported on the support frame, the support frame includes a support rod provided on the premixing nozzle, a support sleeve is provided at the end of the support rod, and the inclined channel is supported in the support sleeve.

[0013] Furthermore, the premixing nozzle is composed of an upper section, a middle section, and a lower end from top to bottom, the diameter of the lower section is larger than the diameter of the upper section, the upper section and the lower section are connected through the middle section, and the side wall of the middle section is an inclined surface; the inclined channel is connected to the premixing chamber at the middle section.

[0014] Furthermore, it also includes a secondary desulfurization tower, the secondary desulfurization tower is a regeneration-desulfurization-tower desulfurization tower, the upper section of the regeneration-desulfurization-tower desulfurization tower is the regeneration section, the lower section of the regeneration-desulfurization-tower desulfurization tower is the desulfurization section, the coal gas discharged from the top of the primary desulfurization tower enters the bottom of the desulfurization section, and contacts with the lean absorption liquid sprayed from the top of the desulfurization section in reverse direction, the lean absorption liquid sprayed from the top of the desulfurization section further absorbs H2S and HCN in the coal gas, and the coal gas with H2S and HCN removed is discharged from the top of the desulfurization section; The rich liquid pumped out from the bottom of the desulfurization section by the secondary solution pump is sprayed into the top of the regeneration section through the ejector. At the same time, the tail gas from the primary oxidation regeneration tower is also sprayed into the top of the regeneration section through the ejector. The tail gas from the primary oxidation regeneration tower is fully mixed with the rich liquid and enters the regeneration section. After the rich liquid is regenerated in the regeneration section, it flows by gravity into the desulfurization section for circulation and spraying. The regenerated tail gas from the regeneration section is returned to the coal gas.

[0015] Alternatively: a secondary desulfurization tower and a secondary oxidation regeneration tower are provided; the coal gas discharged from the top of the primary desulfurization tower enters the lower part of the secondary desulfurization tower, and contacts with the lean absorption liquid sprayed from the top of the secondary desulfurization tower in reverse direction; the lean absorption liquid sprayed from the top of the secondary desulfurization tower further absorbs H2S and HCN in the coal gas, and the coal gas with H2S and HCN removed is discharged from the top of the secondary desulfurization tower; The rich liquid at the bottom of the secondary desulfurization tower is pressurized by the secondary solution pump, mixed with the tail gas sent from the primary oxidation regeneration tower through the premixing nozzle and sent to the bottom of the secondary oxidation regeneration tower. The height of the secondary oxidation regeneration tower is lower than that of the secondary desulfurization tower. Air and rich liquid flow in the same direction and mix and contact in the secondary oxidation regeneration tower. The rich liquid is oxidized and regenerated under the action of the catalyst using oxygen in the air. The regenerated lean liquid is collected by a gas-liquid separator, and the regenerated lean liquid is pressurized by a lean liquid pump and sent to the top of the secondary desulfurization tower for circulating spraying. The elemental sulfur oxidized in the secondary oxidation regeneration tower is floated to the upper part of the secondary oxidation regeneration tower to form sulfur foam, and the regenerated tail gas from the secondary oxidation regeneration tower is returned to the coal gas.

[0016] The beneficial effects of the present invention are as follows: a premixing nozzle is arranged in the regeneration tower, and a high-efficiency premixing nozzle is used to premix the rich liquid and compressed air before spraying them out, and the amount of regeneration air is only 45% of that of the traditional regeneration tower. At the same time, the oxygen content in the regeneration air is controlled below 15% (Vol), and can be directly mixed back into the coal gas, which is friendly to the working environment; The regeneration tower is located at a low position. After the desulfurization liquid is pumped to the spray device through the lean liquid pump, its temperature has been greatly reduced, which is beneficial to improving the desulfurization effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a process flow chart of the present invention.

[0018] Figure 2 It is a structural diagram of the primary oxidation regeneration tower.

[0019] Figure 3 It is a schematic diagram of the structure of the premixing nozzle.

[0020] Figure 4 It is a process flow chart of the present invention when a regeneration-desulfurization tower is added as a secondary desulfurization tower.

[0021] Figure 5 It is a process flow chart of the present invention when a secondary desulfurization tower and a secondary oxidation regeneration tower are added. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0023] Embodiment 1, refer to Figure 1 , Figure 2 , Figure 3 , a low-tower regeneration coal gas desulfurization process, comprising the following steps: ①. The coke oven gas to be treated is sent to the lower part of the primary desulfurization tower 11, and is reversely contacted with the lean absorption liquid sprayed from the top of the primary desulfurization tower 11. The lean absorption liquid sprayed from the top of the primary desulfurization tower 11 absorbs H2S and HCN in the gas, and the gas with H2S and HCN removed is discharged from the top of the primary desulfurization tower 11; ②. The rich liquid at the bottom of the primary desulfurization tower 11 is pressurized by the primary solution pump, and then mixed with compressed air through the premixing nozzle 2 and sent to the bottom of the primary oxidation regeneration tower 1. The height of the primary oxidation regeneration tower 1 is lower than that of the primary desulfurization tower 11. In the primary oxidation regeneration tower 1, the air and the rich liquid flow in the same direction and are mixed and contacted. The rich liquid is oxidized and regenerated under the action of the catalyst by using the oxygen in the air. The regenerated regenerated lean liquid is collected by the gas-liquid separator 13, and the regenerated lean liquid is pressurized by the lean liquid pump 14 and sent to the top of the primary desulfurization tower for circulation spraying. The elemental sulfur generated by oxidation in the primary oxidation regeneration tower is floated to the upper part of the primary oxidation regeneration tower 2 to form sulfur foam. The height of the primary oxidation regeneration tower 1 is lower than that of the primary desulfurization tower 11, so the lean liquid needs to be pressurized by the lean liquid pump 14 and sent to the top of the primary desulfurization tower 11 for circulation spraying. The regenerated lean liquid is sucked and sent back to the desulfurization liquid spraying device 12, and its temperature has been greatly reduced, which is conducive to improving the desulfurization effect.

[0024] The catalyst may be a catalyst in the prior art, such as a HPF catalyst, a DDS catalyst, a PXT catalyst, etc., which will not be described in detail here.

[0025] The coke oven gas desulfurization system used to implement the above process includes a primary desulfurization tower 11 and a primary oxidation regeneration tower 1. The primary desulfurization tower 11 is filled with fillers, a gas inlet is provided at the lower part of the primary desulfurization tower 11, a desulfurization liquid spraying device 12 is provided at the upper part of the primary desulfurization tower 11, a gas outlet is provided at the top of the primary desulfurization tower 11, and a rich liquid outlet is provided at the bottom of the primary desulfurization tower 11.

[0026] The height of the primary oxidation regeneration tower 1 is lower than the primary desulfurization tower 11. The primary oxidation regeneration tower 1 is provided with a gas-liquid separator 13 for collecting lean liquid. The top of the primary oxidation regeneration tower 1 is provided with a sulfur foam outlet. The bottom of the primary oxidation regeneration tower 1 is provided with a premixing nozzle 2 for mixing compressed air and rich liquid.

[0027] It also includes a lean liquid pump 14, which is connected to the gas-liquid separator 13 and the desulfurized liquid spraying device 12 through pipelines, so as to transport the lean liquid collected by the low-level gas-liquid separator 13 to the high-level desulfurized liquid spraying device 12. The gas-liquid separator 13 is a mature technology in the prior art and will not be described in detail here.

[0028] In one embodiment, a cooler 15 is provided on the pipeline between the lean liquid pump 14 and the desulfurization liquid spraying device 12, and / or on the pipeline between the lean liquid pump 14 and the gas-liquid separator 13. The regenerated lean liquid is cooled by the cooler 15 and then pumped back to the desulfurization liquid spraying device 12, which is beneficial to further cooling the regenerated lean liquid. The cooler 15 can generally be a water cooler.

[0029] In one embodiment, the coke oven gas desulfurization system further comprises a sulfur foam tank 16 capable of receiving the sulfur foam flowing out of the sulfur foam outlet. The elemental sulfur generated by oxidation in the primary oxidation regeneration tower 1 is floated to the top of the tower by air to form sulfur foam, which then flows into the sulfur foam tank 16 for collection.

[0030] The premixing nozzle 2 is vertically arranged at the bottom of the primary oxidation regeneration tower 1. The premixing nozzle 2 has a vertically arranged premixing chamber. The premixing chamber extends upward to the upper end surface of the premixing nozzle to form an upward spray port 3. The premixing nozzle 2 is also provided with a compressed air inlet 4 and a rich liquid inlet 5. The compressed air inlet 4 and the rich liquid inlet 5 are both connected to the premixing chamber. The compressed air inlet is connected to an air compressor, which can be a traditional air compressor or a blower, as long as it can provide compressed air. The rich liquid inlet is connected to the rich liquid outlet at the bottom of the primary desulfurization tower 11. In one embodiment, the premixing chamber extends downward to the lower end surface of the premixing nozzle 2 to form a rich liquid inlet 5, which is more convenient for the rich liquid at the bottom of the previous desulfurization tower to enter the premixing nozzle. Of course, the rich liquid inlet 5 can also be separately arranged on the side wall of the premixing nozzle 2.

[0031] In the present invention, a premixing nozzle 2 is provided in the primary oxidation regeneration tower 1. The rich liquid and compressed air are premixed and then sprayed out by the premixing nozzle 2. The regeneration air consumption is only 45% of that of the traditional regeneration tower. At the same time, the oxygen content in the regeneration air is controlled below 15% (Vol), and can be directly mixed back into the coal gas, which is friendly to the working environment.

[0032] In one embodiment, the compressed air inlet 4 and the rich liquid inlet 5 are not in a straight line, so that the compressed air entering through the compressed air inlet 4 can be better mixed with the rich liquid entering through the rich liquid inlet 5 .

[0033] In one embodiment, the compressed air inlet 4 is specifically arranged as follows: the premixing nozzle 2 is provided with an inclined channel 6 which is connected to the premixing chamber and is inclined from top to bottom to outside; the inclined channel 6 is also provided with a transversely arranged air intake channel 7 which is connected to the inclined channel 6; the end of the air intake channel 7 forms the compressed air inlet 4, which can form a better effect of mixing compressed air and rich liquid.

[0034] In one embodiment, a support frame is provided on the premixing nozzle 2, and the inclined channel 6 is supported on the support frame to make the inclined channel 6 more stable. The specific structural form of the support frame can be: the support frame includes a support rod 8 provided on the premixing nozzle 2, a support sleeve 9 is provided at the end of the support rod 8, and the inclined channel 6 is supported in the support sleeve 9.

[0035] In one embodiment, a steam inlet 10 is formed at the end of the inclined channel 6. When there is a blockage in the premixing nozzle, steam can be passed into the inclined channel through the steam inlet 10 to clear the blockage.

[0036] In one embodiment, the premixing nozzle 2 is composed of an upper section 2-1, a middle section 2-2, and a lower section 2-3 from top to bottom. The diameter of the lower section 2-3 is larger than the diameter of the upper section 2-1. The upper section 2-1 and the lower section 2-3 are connected by the middle section 2-2. The side wall of the middle section 2-2 is an inclined surface. The inclined channel is connected to the premixing chamber at the middle section 2-2. The variable diameter structure can achieve better mixing of compressed air and rich liquid.

[0037] Example 2, refer to Figure 4 , on the basis of the primary desulfurization in the first embodiment, a secondary desulfurization is further performed, that is, it also includes a secondary desulfurization tower, the secondary desulfurization tower is a regeneration-desulfurization-tower desulfurization tower, the regeneration-desulfurization-tower desulfurization tower is a mature technology in the prior art, and will not be repeated here, the upper section of the regeneration-desulfurization-tower desulfurization tower is the regeneration section 17, the lower section of the regeneration-desulfurization-tower desulfurization tower is the desulfurization section 18, the coal gas discharged from the top of the primary desulfurization tower enters the bottom of the desulfurization section 18, and contacts with the absorption lean liquid sprayed from the top of the desulfurization section 18 in reverse direction, the absorption lean liquid sprayed from the top of the desulfurization section further absorbs H2S and HCN in the coal gas, and the coal gas with H2S and HCN removed is discharged from the top of the desulfurization section; The rich liquid drawn from the bottom of the desulfurization section 18 by the secondary solution pump 20 is sprayed into the top of the regeneration section 17 through the ejector 19. At the same time, the tail gas from the primary oxidation regeneration tower 1 is also sprayed into the top of the regeneration section 17 through the ejector 19. The tail gas from the primary oxidation regeneration tower 1 is fully mixed with the rich liquid and enters the regeneration section 17. After the rich liquid is regenerated by the regeneration section 17, it flows by gravity into the desulfurization section 18 for circulating spraying. The regenerated tail gas of the regeneration section 17 is the tail gas from the primary oxidation regeneration tower 1 after consuming oxygen again. At this time, the oxygen content in the tail gas is cleared and can be returned to the coal gas.

[0038] Example 3, refer to Figure 5 On the basis of the primary desulfurization in the first embodiment, a secondary desulfurization is performed. The secondary desulfurization method is the same as the primary desulfurization method, that is, the desulfurization process is repeated, except that the tail gas generated by the primary oxidation regeneration tower is used as the regeneration air of the secondary oxidation regeneration tower, that is, a secondary desulfurization tower 11' and a secondary oxidation regeneration tower 1' are provided; The coal gas discharged from the top of the primary desulfurization tower 11 enters the lower part of the secondary desulfurization tower 11', and contacts with the lean absorption liquid sprayed from the top of the secondary desulfurization tower 11' in reverse direction. The lean absorption liquid sprayed from the top of the secondary desulfurization tower 11' further absorbs H2S and HCN in the coal gas, and the coal gas with H2S and HCN removed is discharged from the top of the secondary desulfurization tower 11'. The rich liquid at the bottom of the secondary desulfurization tower 11' is pressurized by a secondary solution pump, and then mixed with the tail gas sent from the primary oxidation regeneration tower 1 through a premixing nozzle 2' and sent to the bottom of the secondary oxidation regeneration tower 1'. The height of the secondary oxidation regeneration tower 1' is lower than that of the secondary desulfurization tower 11'. In the secondary oxidation regeneration tower 1', air and rich liquid flow in the same direction and are mixed and contacted. The rich liquid is oxidized and regenerated under the action of a catalyst using oxygen in the air. The regenerated regenerated lean liquid is collected by a gas-liquid separator, and the regenerated lean liquid is pressurized by a lean liquid pump and sent to the top of the secondary desulfurization tower 11' for cyclic spraying. The elemental sulfur oxidized in the secondary oxidation regeneration tower 1' is floated to the upper part of the secondary oxidation regeneration tower 1' to form sulfur foam. The regenerated tail gas of the secondary oxidation regeneration tower 1' is the tail gas from the primary oxidation regeneration tower 1 after the tail gas consumes oxygen again. At this time, the oxygen content in the tail gas is cleared and can be returned to the coal gas.

[0039] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0040] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low-tower regeneration coal gas desulfurization process, characterized in that The steps include: ①. The coke oven gas to be treated is sent to the lower part of the primary desulfurization tower, and is reversely contacted with the lean absorption liquid sprayed from the top of the primary desulfurization tower. The lean absorption liquid sprayed from the top of the primary desulfurization tower absorbs H2S and HCN in the gas, and the gas with H2S and HCN removed is discharged from the top of the primary desulfurization tower; ②. The rich liquid at the bottom of the primary desulfurization tower is pressurized by the primary solution pump, mixed with compressed air through a premixing nozzle and sent to the bottom of the primary oxidation regeneration tower. The height of the primary oxidation regeneration tower is lower than that of the primary desulfurization tower. In the primary oxidation regeneration tower, air and rich liquid flow in the same direction and mix and contact. The rich liquid is oxidized and regenerated under the action of a catalyst using oxygen in the air. The regenerated lean liquid is collected by a gas-liquid separator and pressurized by a lean liquid pump and sent to the top of the primary desulfurization tower for circulating spraying. The elemental sulfur oxidized in the primary oxidation regeneration tower is floated to the upper part of the primary oxidation regeneration tower to form sulfur foam.

2. The low-tower regeneration coal gas desulfurization process according to claim 1, characterized in that: In step ②, the regenerated lean liquid is cooled in the cooler and then enters the top of the primary desulfurization tower again for recycling.

3. The low-tower regeneration coal gas desulfurization process according to claim 1, characterized in that: The premixing nozzle is vertically arranged at the bottom of the regeneration tower, and the premixing nozzle has a vertically arranged premixing chamber, and the premixing chamber extends upward to the upper end surface of the premixing nozzle to form an upward spraying port, and the rich liquid and compressed air mixed by the premixing nozzle are sprayed out from the spraying port; The premixing nozzle is also provided with a compressed air inlet and a rich liquid inlet, both of which are connected to the premixing chamber, the compressed air inlet is connected to an air compressor to pump in compressed air, and the rich liquid inlet is connected to the rich liquid outlet at the bottom of the primary desulfurization tower, and the rich liquid at the bottom of the primary desulfurization tower enters the premixing nozzle through the rich liquid inlet.

4. The low-tower regeneration coal gas desulfurization process according to claim 3, characterized in that: The premixing chamber extends downward to the lower end surface of the premixing nozzle to form a rich liquid inlet.

5. The low-tower regeneration coal gas desulfurization process according to claim 4, characterized in that: The premixing nozzle is provided with an inclined channel which is connected to the premixing chamber and is inclined from top to bottom outward. The inclined channel is also provided with a transversely arranged air intake channel which is connected to the inclined channel. The end of the air intake channel forms the compressed air inlet.

6. The low-tower regeneration coal gas desulfurization process according to claim 5, characterized in that: A steam inlet is formed at the end of the inclined channel. When a blockage is formed in the premixing nozzle, steam is passed into the inclined channel through the steam inlet to clear the blockage.

7. The low-tower regeneration coal gas desulfurization process according to claim 5, characterized in that: The premixing nozzle is provided with a support frame, the inclined channel is supported on the support frame, the support frame includes a support rod provided on the premixing nozzle, a support sleeve is provided at the end of the support rod, and the inclined channel is supported in the support sleeve.

8. The low-tower regeneration coal gas desulfurization process according to claim 3, characterized in that: The premixing nozzle is composed of an upper section, a middle section, and a lower end from top to bottom. The diameter of the lower section is greater than the diameter of the upper section. The upper section and the lower section are connected through the middle section. The side wall of the middle section is an inclined surface. The inclined channel is connected to the premixing chamber at the middle section.

9. The low-tower regeneration coal gas desulfurization process according to claim 1, characterized in that: It also includes a secondary desulfurization tower, which is a regeneration-desulfurization-tower desulfurization tower, the upper section of the regeneration-desulfurization-tower desulfurization tower is the regeneration section, and the lower section of the regeneration-desulfurization-tower desulfurization tower is the desulfurization section. The coal gas discharged from the top of the primary desulfurization tower enters the bottom of the desulfurization section and contacts with the lean absorption liquid sprayed from the top of the desulfurization section in reverse direction. The lean absorption liquid sprayed from the top of the desulfurization section further absorbs H2S and HCN in the coal gas, and the coal gas with H2S and HCN removed is discharged from the top of the desulfurization section. The rich liquid pumped out from the bottom of the desulfurization section by the secondary solution pump is sprayed into the top of the regeneration section through the ejector. At the same time, the tail gas from the primary oxidation regeneration tower is also sprayed into the top of the regeneration section through the ejector. The tail gas from the primary oxidation regeneration tower is fully mixed with the rich liquid and enters the regeneration section. After the rich liquid is regenerated in the regeneration section, it flows by gravity into the desulfurization section for circulation and spraying. The regenerated tail gas from the regeneration section is returned to the coal gas.

10. The low-tower regeneration coal gas desulfurization process according to claim 1, characterized in that: set up Secondary desulfurization tower and secondary oxidation regeneration tower; The coal gas discharged from the top of the primary desulfurization tower is sent to the lower part of the secondary desulfurization tower, and is reversely contacted with the lean absorption liquid sprayed from the top of the secondary desulfurization tower. The lean absorption liquid sprayed from the top of the secondary desulfurization tower further absorbs H2S and HCN in the coal gas, and the coal gas with H2S and HCN removed is discharged from the top of the secondary desulfurization tower; The rich liquid at the bottom of the secondary desulfurization tower is pressurized by the secondary solution pump, mixed with the tail gas sent from the primary oxidation regeneration tower through the premixing nozzle and sent to the bottom of the secondary oxidation regeneration tower. The height of the secondary oxidation regeneration tower is lower than that of the secondary desulfurization tower. Air and rich liquid flow in the same direction and mix and contact in the secondary oxidation regeneration tower. The rich liquid is oxidized and regenerated under the action of the catalyst using oxygen in the air. The regenerated lean liquid is collected by a gas-liquid separator, and the regenerated lean liquid is pressurized by a lean liquid pump and sent to the top of the secondary desulfurization tower for circulating spraying. The elemental sulfur oxidized in the secondary oxidation regeneration tower is floated to the upper part of the secondary oxidation regeneration tower to form sulfur foam, and the regenerated tail gas from the secondary oxidation regeneration tower is returned to the coal gas.

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