Tail gas recycling device of desulfurization regeneration tower

Abstract

The utility model discloses a tail gas recycling device for a desulfurization regeneration tower. The tail gas recycling device comprises a tail gas circulating process, a tail gas recycling process and a tail gas destroying process, the tail gas circulation process comprises a first regeneration tower and a second regeneration tower, a desulfurization solution circularly flows into the second regeneration tower after passing through the first regeneration tower, released diffused gas is mixed with compressed air after passing through a diffusion port and a gas booster pump, and a gas source in the second regeneration tower is mixed with the desulfurization solution and then enters a foam tank; diffused gas of the second regeneration tower is connected with a tail gas recovery process through a diffusion port; the tail gas recovery process comprises an alkaline washing tower, an acid washing tower and a water washing tower, diffused gas passes through the alkaline washing tower, the acid washing tower and the water washing tower and then is connected with the tail gas damage process, and the alkaline washing tower, the acid washing tower and the water washing tower are further connected with a desulfurization liquid section, a foam tank, an ammonium sulfate mother liquor section and an ammonia distillation wastewater section respectively; one end of the incinerator is connected with a tail gas recovery process and compressed air mixture, and the other end of the incinerator directly discharges gas.

Description

Technical Field

[0001] The invention belongs to the field of environmental protection and coke oven gas purification, and mainly relates to a desulfurization regeneration tower tail gas recycling device. Background Art

[0002] In order to achieve recycling, the raw gas from coke ovens needs to be purified. Among the traditional desulfurization methods, wet desulfurization is a common method, which specifically adopts the following steps: First, the gas enters the desulfurization tower, and the desulfurization liquid and the gas are in reverse contact to absorb most of the hydrogen sulfide and hydrogen cyanide in the gas, and a catalyst is added to the desulfurization liquid to accelerate the above reaction rate, oxidize S2- into elemental sulfur and polysulfur, and reduce a small amount of elemental sulfur in the absorption liquid, thereby purifying the gas. The gas enters the regeneration tower from the desulfurization tower and contacts with the compressed air at the bottom of the tower. The solution is regenerated to produce sulfur particles to form elemental sulfur foam. The desulfurization liquid that generates sulfur foam continues to enter the desulfurization section for continued use. At the top of the regeneration tower, a vented gas is generated. The gas contains harmful gases such as hydrogen sulfide and hydrogen cyanide, which are extremely harmful to the human body and the environment. If the vented gas is not treated, the ammonia nitrogen concentration is generally greater than 500mg / m³, and the hydrogen sulfide concentration is also higher than 200mg / m³, which is far greater than the exhaust emission standard. If it enters the tail gas treatment device directly, it cannot reduce the consumption of subsequent tail gas treatment auxiliary materials, and the tail gas contains hydrogen sulfide and hydrogen cyanide which can be further extracted.

[0003] At present, there are various ways to purify the tail gas from the regeneration tower, most of which are directly entering the coke oven, dry quenching, RTO furnace and other incineration methods. However, there are also the following problems:

[0004] Filling with pressurized air directly increases the total amount of ammonia and hydrogen sulfide emissions;

[0005] The higher the concentration of the two salts (ammonium thiosulfate and ammonium thiocyanate) in the desulfurization liquid, the higher the H2S and lower the NH3 in the regenerated tail gas, which affects the subsequent emission indicators and treatment difficulty.

[0006] The gas is released directly into the coke oven incineration regeneration tower. The gas contains halogen organic matter and is highly corrosive, and the coke oven body is often damaged to varying degrees, bricks fall off, etc.

[0007] Using water washing method to treat regeneration tail gas not only consumes excess steam and water, but also contains high value-added organic matter in the tail gas that cannot be recovered.

[0008] The exhaust gas from the regeneration tower enters the CDQ annular flue to supply air, which makes it difficult to control the amount of air introduced and increases the burn loss rate. When operating at low load, the exhaust gas cannot be fully processed because the CDQ furnace does not require a large amount of air supply.

[0009] The use of RTO furnace to treat the exhaust gas from the regeneration tower cannot completely purify sulfur-containing, nitrogen-containing halogen organic matter and cannot be discharged directly. Summary of the invention

[0010] In order to overcome the defects in the prior art that the exhaust gas treatment is not conducive to meeting the emission standards, and the exhaust gas will cause various damages to the original furnace body no matter it is combined with coal gas or air to enter the furnace, the utility model provides a desulfurization tower regeneration tower exhaust gas circulation treatment device which can solve the problem of H2S, NH3 and other gases being recycled in the subsequent treatment of the exhaust gas from the regeneration tower of the desulfurization section, reduce the emission risk, save the cost of exhaust gas treatment, and achieve sustainable development.

[0011] The technical solution adopted by the utility model to achieve the above-mentioned purpose is:

[0012] A desulfurization regeneration tower tail gas recycling device comprises a tail gas circulation process, a tail gas recovery process and a tail gas destruction process, wherein the tail gas circulation process is connected to one end of the tail gas recovery process, and the other end of the tail gas recovery process is connected to the tail gas destruction process; the tail gas circulation process comprises a first regeneration tower and a second regeneration tower, and the vented gas released after the desulfurization liquid passes through the first regeneration tower is pressurized by a gas booster pump through the tower top venting port and mixed with compressed air, and enters the second regeneration tower as a gas source, and the desulfurization liquid circulates into the second regeneration tower after passing through the first regeneration tower, and the gas source in the second regeneration tower is mixed with the desulfurization liquid to fill After the elemental sulfur is reabsorbed through a partial circulation, it enters the foam tank for treatment. The exhaust gas from the second regeneration tower is connected to the tail gas recovery process through the exhaust port on the top of the tower. The tail gas recovery process includes an alkali washing tower, an acid washing tower and a water washing tower. The exhaust gas passes through the alkali washing tower, the acid washing tower and the water washing tower and is connected to the tail gas destruction process. The alkali washing tower is also connected to the desulfurization liquid section and the foam tank, the acid washing tower is connected to the ammonium sulfate mother liquor section, and the water washing tower is connected to the ammonia vaporization wastewater section. The tail gas destruction process includes an incinerator, one end of the incinerator is connected to the tail gas recovery process and the compressed air mixture, and the other end of the incinerator directly discharges the gas.

[0013] Furthermore, the desulfurization liquid inlet at the bottom of the first regeneration tower is connected to the desulfurization liquid pipeline, the desulfurization liquid outlet at the bottom of the first regeneration tower is connected to the compression pipeline, the circulating liquid outlet at the top of the first regeneration tower is connected to the circulating liquid inlet of the second regeneration tower, the foam outlet of the second regeneration tower is connected to the foam tank, and the vented gas of the second regeneration tower is connected to the inlet of the alkali washing tower through the venting port at the top of the tower.

[0014] Furthermore, the scrubbing gas outlet of the alkali scrubbing tower is connected to the scrubbing gas inlet of the acid scrubbing tower, the solution outlet of the alkali scrubbing tower is connected to the desulfurization liquid section, the scrubbing gas outlet of the acid scrubbing tower is connected to the scrubbing gas inlet of the water scrubbing tower, the solution port of the acid scrubbing tower is connected to the ammonium sulfate mother liquor section, the scrubbing gas outlet of the water scrubbing tower is connected to the tail gas destruction process, and the solution outlet of the water scrubbing tower is connected to the ammonia evaporation wastewater section.

[0015] Preferably, the desulfurization liquid in the foam tank is used to spray at the bottom of the alkali washing tower to wash away H2S and sulfur in the released gas, and the dilute alkali is used to spray at the top to remove acid mist and H2S in the released gas. The circulating liquid enters the ammonia vapor to decompose the fixed ammonium, the washed gas enters the acid washing tower, and the solution enters the desulfurization liquid section.

[0016] Preferably, ammonium sulfate solution is used in the acid washing tower, and after removing NH3, the solution returns to the ammonium sulfate mother liquor section, and the washing gas enters the water washing tower.

[0017] Preferably, the spraying liquid in the water scrubber is the ammonia evaporation wastewater from the ammonia evaporation unit. After the acid mist is removed by spraying, the wastewater enters the sewage treatment process, and the washing gas enters the tail gas destruction process.

[0018] Preferably, the incinerator is an acid-making incinerator.

[0019] The vented gas from the desulfurization regeneration tower in the utility model is pressurized through the venting port on the top of the tower and then mixed with compressed air, and enters another regeneration tower as a gas source, thereby reducing the use of pressurized air, and is mixed with the desulfurization liquid and fully circulated to realize the reabsorption of elemental sulfur, so that the substances in the vented gas react again, thereby increasing the reaction efficiency; after the vented gas from the desulfurization regeneration tower is reabsorbed, it is discharged at the top of the tower, and is sprayed with the spraying liquid of each section by three absorption towers respectively to wash away the absorbable part of the vented gas, and then returns to each section for recycling, thereby achieving the effect of repeated utilization; the tail gas destruction process selects an acid-making incinerator for thermal destruction and combustion, and adopts a thermal destruction method to directly burn and decompose the washed vented gas. Because the acid-making incinerator is designed to enter the furnace as elemental sulfur, and the vented gas contains less of this substance, it will not affect the subsequent emissions. If the vented gas is used as the air intake source, the loss of compressed air can be effectively reduced, and it can also be reasonably discharged after subsequent treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the process flow diagram of the utility model.

[0021] In the figure: a first regeneration tower 1, a second regeneration tower 2, a gas booster pump 3, an alkali washing tower 4, an acid washing tower 5, a water washing tower 6, an exhaust gas circulation process 7, an exhaust gas recovery process 8, an exhaust gas destruction process 9, and an incinerator 10. DETAILED DESCRIPTION

[0022] like Figure 1As shown, the tail gas recycling device of the desulfurization regeneration tower of this embodiment includes a tail gas circulation process 7, a tail gas recovery process 8 and a tail gas destruction process 9, wherein the tail gas circulation process 7 is connected to one end of the tail gas recovery process 8, and the other end of the tail gas recovery process 8 is connected to the tail gas destruction process 9; the tail gas circulation process 7 includes a first regeneration tower 1 and a second regeneration tower 2, and the vented gas released after the desulfurization liquid passes through the first regeneration tower 1 is pressurized by the gas booster pump 3 through the tower top venting port and mixed with the compressed air, and enters the second regeneration tower 2 as a gas source, and the desulfurization liquid circulates into the second regeneration tower 2 after passing through the first regeneration tower 1, and the gas source in the second regeneration tower 2 is mixed with the desulfurization liquid to fill After the elemental sulfur is reabsorbed through a partial circulation, it enters the foam tank for treatment. The exhaust gas from the second regeneration tower 2 is connected to the tail gas recovery process 8 through the exhaust port on the top of the tower. The tail gas recovery process 8 includes an alkali washing tower 4, an acid washing tower 5 and a water washing tower 6. The exhaust gas passes through the alkali washing tower 4, the acid washing tower 5 and the water washing tower 6 and is connected to the tail gas destruction process 9. The alkali washing tower 4 is also connected to the desulfurization liquid section and the foam tank, the acid washing tower 5 is connected to the ammonium sulfate mother liquor section, and the water washing tower 6 is connected to the ammonia wastewater section. The tail gas destruction process 9 includes an incinerator 10, one end of the incinerator 10 is connected to the tail gas recovery process 8 and the compressed air mixture, and the other end of the incinerator 10 directly discharges the gas.

[0023] Furthermore, the desulfurization liquid inlet at the bottom of the first regeneration tower 1 is connected to the desulfurization liquid pipeline, the desulfurization liquid outlet at the bottom of the first regeneration tower 1 is connected to the compression pipeline, the circulating liquid outlet at the top of the first regeneration tower 1 is connected to the circulating liquid inlet of the second regeneration tower 2, the foam outlet of the second regeneration tower 2 is connected to the foam tank, and the vented gas of the second regeneration tower 2 is connected to the inlet of the alkali washing tower 4 through the venting port on the top of the tower.

[0024] Furthermore, the scrubbing gas outlet of the alkali scrubbing tower 4 is connected to the scrubbing gas inlet of the acid scrubbing tower 5, the solution outlet of the alkali scrubbing tower 4 is connected to the desulfurization liquid section, the scrubbing gas outlet of the acid scrubbing tower 5 is connected to the scrubbing gas inlet of the water scrubbing tower 6, the solution port of the acid scrubbing tower 5 is connected to the ammonium sulfate mother liquor section, the scrubbing gas outlet of the water scrubbing tower 6 is connected to the tail gas destruction process, and the solution outlet of the water scrubbing tower 6 is connected to the ammonia evaporation wastewater section.

[0025] Preferably, the desulfurization liquid in the foam tank is sprayed at the bottom of the alkali washing tower 4 to wash away H2S and sulfur in the released gas, and the dilute alkali is sprayed at the top to remove acid mist and H2S in the released gas. The circulating liquid enters the ammonia vapor to decompose the fixed ammonium, and the washed gas enters the acid washing tower 5, and the solution enters the desulfurization liquid section.

[0026] Preferably, ammonium sulfate solution is used in the acid washing tower 5, and after removing NH3, the solution returns to the ammonium sulfate mother liquor section, and the washing gas enters the water washing tower 6.

[0027] Preferably, the spraying liquid in the water washing tower 6 is the ammonia evaporation wastewater of the ammonia evaporation unit. After the acid mist is removed by spraying, the wastewater enters the sewage treatment process, and the washing gas enters the tail gas destruction process.

[0028] Preferably, the incinerator 10 is an acid-producing incinerator.

[0029] like Figure 1 As shown, the working principle of the utility model is as follows:

[0030] In the tail gas circulation process 10, after the desulfurization liquid in the first regeneration tower 1 is fully integrated with the pressurized air at the bottom of the tower, the sulfur element foam generated by oxidation regeneration enters the foam tank for treatment, and the generated regeneration tower exhaust gas rises through the exhaust port, and after the pipeline is pressurized by the gas booster pump 3, it is fully mixed with the pressurized air at the bottom of the second regeneration tower 2 along the pipeline and then passed into the regeneration tower 2. Using the exhaust gas from the regeneration tower 2 as the gas source reduces the use of pressurized air, allows the substances in the exhaust gas to react again, and increases the reaction efficiency.

[0031] In the tail gas recovery process 8, the exhaust gas from the regeneration tower 2 first enters the alkali washing tower 4, and the desulfurization liquid is used to spray down to wash away the H2S and sulfur in the exhaust gas, and the upper section uses dilute alkali spraying to remove the acid mist and H2S in the exhaust gas. The circulating liquid enters the ammonia evaporation to decompose the fixed ammonium, and the washed gas enters the acid washing tower 5. The same principle is also used for reverse contact, but the acid washing tower 5 uses ammonium sulfate solution. After removing NH3, the solution returns to the ammonium sulfate section, and the washing gas enters the water washing tower 6. The ammonia evaporation wastewater of the ammonia evaporation unit is used as the spraying liquid in the water washing tower 6 to remove the acid mist, and the wastewater enters the sewage treatment process. The washing gas enters the tail gas destruction process 9.

[0032] In the tail gas destruction process 9, the utility model adopts a thermal destruction method to directly burn and decompose the washed exhaust gas. The common thermally destructive furnace bodies in coal coking enterprises include coke ovens, dry quenching furnaces, RTO furnaces, etc. Although they are washed by the water washing tower 6, substances such as H2S and NH3 will still exist in the exhaust gas from the regeneration tower, and corrosion-resistant materials were not selected at the beginning of the design of this part of the furnace body, so it is not recommended to directly enter the furnace for combustion. The utility model uses an acid-making incinerator 10 for thermal destruction combustion, because the acid-making incinerator is designed to enter the furnace with sulfur element, and the exhaust gas contains less of this substance, which will not affect subsequent emissions. If the exhaust gas is used as the air intake source, the loss of compressed air can be effectively reduced, and it can also be reasonably discharged after subsequent treatment.

[0033] The utility model has the advantages of simple operation, low operation cost and small equipment maintenance, and has higher comprehensive performance than the existing waste gas treatment methods, and balanced use of waste gas; it realizes the comprehensive use of VOC treatment methods, can ensure that the harmful substances in the emitted gas are minimized, and can also utilize the recovered substances.

Claims

1. A desulfurization regeneration tower tail gas recycling device, characterized in that: The process comprises a tail gas circulation process, a tail gas recovery process and a tail gas destruction process. The tail gas circulation process is connected to one end of the tail gas recovery process, and the other end of the tail gas recovery process is connected to the tail gas destruction process. The tail gas circulation process comprises a first regeneration tower and a second regeneration tower. The desulfurized liquid is released after passing through the first regeneration tower. The desulfurized liquid is pressurized by a gas booster pump through the tower top release port and then mixed with compressed air to enter the second regeneration tower as a gas source. The desulfurized liquid passes through the first regeneration tower and circulates into the second regeneration tower. The gas source in the second regeneration tower is mixed with the desulfurized liquid and fully circulated to realize elemental sulfur After reabsorption, it enters the foam tank for treatment, and the vented gas from the second regeneration tower is connected to the tail gas recovery process through the venting port on the top of the tower; the tail gas recovery process includes an alkali washing tower, an acid washing tower and a water washing tower, and the vented gas is connected to the tail gas destruction process after passing through the alkali washing tower, the acid washing tower and the water washing tower. The alkali washing tower is also connected to the desulfurization liquid section and the foam tank, the acid washing tower is connected to the ammonium sulfate mother liquor section, and the water washing tower is connected to the ammonia wastewater section. The tail gas destruction process includes an incinerator, one end of the incinerator is connected to the tail gas recovery process and the compressed air mixture, and the other end of the incinerator directly discharges the gas.

2. The desulfurization regeneration tower tail gas recycling device according to claim 1, characterized in that: The desulfurization liquid inlet at the bottom of the first regeneration tower is connected to the desulfurization liquid pipeline, the desulfurization liquid outlet at the bottom of the first regeneration tower is connected to the compression pipeline, the circulating liquid outlet at the top of the first regeneration tower is connected to the circulating liquid inlet of the second regeneration tower, the foam outlet of the second regeneration tower is connected to the foam tank, and the vented gas of the second regeneration tower is connected to the inlet of the alkali washing tower through the venting port on the top of the tower.

3. The desulfurization regeneration tower tail gas recycling device according to claim 1, characterized in that: The scrubbing gas outlet of the alkali scrubbing tower is connected to the scrubbing gas inlet of the acid scrubbing tower, the solution outlet of the alkali scrubbing tower is connected to the desulfurization liquid section, the scrubbing gas outlet of the acid scrubbing tower is connected to the scrubbing gas inlet of the water scrubbing tower, the solution port of the acid scrubbing tower is connected to the ammonium sulfate mother liquor section, the scrubbing gas outlet of the water scrubbing tower is connected to the tail gas destruction process, and the solution outlet of the water scrubbing tower is connected to the ammonia distillation wastewater section.

4. The desulfurization regeneration tower tail gas recycling device according to claim 3 is characterized in that: The bottom of the alkali washing tower is sprayed with the desulfurization liquid in the foam tank to wash away H2S and sulfur in the released gas, and the top is sprayed with dilute alkali to remove acid mist and H2S in the released gas. The circulating liquid enters the ammonia vapor to decompose the fixed ammonium, the washed gas enters the acid washing tower, and the solution enters the desulfurization liquid section.

5. The desulfurization regeneration tower tail gas recycling device according to claim 3, characterized in that: Ammonium sulfate solution is used in the acid washing tower. After removing NH3, the solution returns to the ammonium sulfate mother liquor section, and the washing gas enters the water washing tower.

6. The desulfurization regeneration tower tail gas recycling device according to claim 3, characterized in that: The spraying liquid in the water washing tower is the ammonia evaporation wastewater from the ammonia evaporation unit. After spraying to remove the acid mist therein, the wastewater enters the sewage treatment process, and the washing gas enters the tail gas destruction process.

7. The desulfurization regeneration tower tail gas recycling device according to claim 1, characterized in that: The incinerator is an acid-making incinerator.

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