阅读说明：本技术 高含硫危险废物处理中的硫回收方法和装置 (Method and device for recovering sulfur in treatment of high-sulfur hazardous waste ) 是由 戴尚武 徐宸玺 毛丁 单博远 何军 于 2020-07-09 设计创作，主要内容包括：本发明涉及高含硫危险废物处理中的硫回收方法和装置,高含硫危险废物经过等离子体气化熔融生成含有H<Sub>2</Sub>S的合成气,将所述的合成气进行一级或多级湿式脱酸,合成气由碱液脱酸生成溶解有硫氢化盐的脱酸液,脱酸液通过催化氧化生成单质硫,本发明的高含硫危险废物处理中的硫回收方法和装置能够将危险废物中硫最终以单质硫的形式得到收集,该方法避免了传统危险废弃物处置过程中SO<Sub>2</Sub>以及二次固废的排放,显著减少二恶英、NO<Sub>x</Sub>的产生。(The invention relates to a method and a device for recovering sulfur in the treatment of high-sulfur hazardous waste, wherein the high-sulfur hazardous waste is gasified and melted by plasma to generate H 2 S, performing one-stage or multi-stage wet deacidification on the synthesis gas, deacidifying the synthesis gas by alkali liquor to generate deacidification liquid in which hydrogen sulfide salt is dissolved, and catalytically oxidizing the deacidification liquid to generate elemental sulfur 2 And the discharge of secondary solid waste can obviously reduce dioxin and NO x Is generated.)

1. A sulfur recovery method in the treatment of high-sulfur hazardous waste is characterized by comprising the following steps:

the high-sulfur hazardous waste is gasified and melted by plasma to generate H₂The synthesis gas of the S is mixed with the nitrogen,

the synthesis gas is subjected to one-stage or multi-stage wet deacidification, the synthesis gas is deacidified by alkali liquor to generate deacidification liquid dissolved with hydrosulphide,

the deacidification liquid generates elemental sulfur through catalytic oxidation.

2. A sulfur recovery process as recited in claim 1, wherein a two-stage wet deacidification is employed, and wherein the first stage is a wet quench deacidification.

3. A process as claimed in claim 2, wherein the liquid-to-gas ratio of synthesis gas to lye in the first stage wet deacidification is in the range of 1 to 10L/m³The liquid-gas ratio of alkali liquor and synthetic gas in the second stage wet deacidification is 0.5-8L/m³。

4. A sulfur recovery process as recited in claim 1, wherein said catalytic oxidation is carried out after the deacidified liquid is subjected to solid-liquid separation to remove precipitates.

5. The sulfur recovery process of claim 1 including the step of purifying said elemental sulfur.

6. A sulfur recovery device in the treatment of high-sulfur hazardous waste is characterized by comprising:

the plasma gasification melting furnace is used for gasifying and melting the hazardous waste with high sulfur content,

one or more stages of wet deacidification towers which are communicated with the plasma gasification melting furnace and used for carrying out wet quenching deacidification on the synthesis gas discharged by the plasma gasification melting furnace,

and the regeneration unit is communicated with the bottom of the wet quenching deacidification tower, and the deacidification liquid of the wet quenching deacidification tower is subjected to elemental sulfur regeneration in the regeneration unit.

7. The sulfur recovery device according to claim 6, wherein a two-stage wet-type deacidification tower is adopted, comprising a venturi wet-type quenching deacidification tower and a washing tower, the plasma gasification melting furnace is communicated with an inlet of the venturi wet-type quenching deacidification tower, a gas phase outlet of the venturi wet-type quenching deacidification tower is communicated with an inlet of the washing tower, and bottoms of the venturi wet-type quenching deacidification tower and the washing tower are communicated with the regeneration unit.

8. The sulfur recovery apparatus according to claim 6, wherein said regeneration unit comprises a regeneration tank, the bottom of the wet type deacidification tower is communicated with the regeneration tank, the bottom of the regeneration tank is provided with an air inlet, the upper part of the regeneration tank is provided with a foam tank, and the foam tank is used for collecting foam containing elemental sulfur.

9. The sulfur recovery device according to claim 8, wherein the regeneration unit further comprises a rich solution tank, the bottom of the wet deacidification tower is communicated with the rich solution tank, the rich solution tank is communicated with the regeneration tank, and the deacidification solution of the wet deacidification tower enters the regeneration tank after being collected by the rich solution tank.

10. The sulfur recovery apparatus according to claim 6, wherein a first solid-liquid separation device is further provided between the wet-type deacidification tower and the regeneration unit for removing the precipitate in the deacidification liquid, the tower bottom of the wet-type deacidification tower is communicated with the first solid-liquid separation device through a pipeline, and the liquid phase outlet of the first solid-liquid separation device is communicated with the regeneration unit through a pipeline.

Technical Field

The invention relates to a method and equipment for treating high-sulfur-content hazardous waste, in particular to a method and a device for recovering sulfur in the treatment of the high-sulfur-content hazardous waste.

Background

The high-sulfur hazardous waste is hazardous waste with the sulfur content of more than 5 percent, and the treatment is complicated because the material composition in the high-sulfur hazardous waste is complicated, and the high-sulfur hazardous waste generally contains heavy metals and organic matters. In the prior art, the general principle isTreating the high-sulfur-content hazardous waste in a plasma gasification melting furnace, directly burning out the synthesis gas at the outlet of the plasma gasification furnace in a secondary combustion chamber after treatment, cooling the flue gas generated by burning out to about 500 ℃ after the heat exchange of the flue gas by a waste heat boiler, then feeding the flue gas into a quenching and semi-drying deacidification tower, and contacting the flue gas with alkali liquor in the process to finish quenching (cooling the flue gas from 500 ℃ to 200 ℃) and deacidifying to generate solid sulfate (CaSO)₄、Na₂SO₄Etc.) and/or sulfites (CaSO)₃、Na₂SO₃And the like), then the flue gas respectively enters a dry-type deacidification tower and a bag-type dust collector with an active carbon injection device to complete deacidification, dedusting and adsorption (heavy metal and dioxin) in the process, and finally enters a wet-type washing tower to further complete deacidification, and then the flue gas is discharged from a chimney through a complex flue gas heating device.

The sulfur in the above process ultimately produces low value-added sulfate (CaSO)₄、Na₂SO₄Etc.) and/or sulfites (CaSO)₃、Na₂SO₃Etc.) which either exist in the form of solid secondary fly ash or enter water, thus invisibly increasing the risk of secondary pollution and failing to effectively recycle the high-content sulfur in the materials.

Meanwhile, the following problems still exist in the prior art.

The synthetic gas at the outlet of the first plasma furnace is directly burnt out in the second combustion chamber. In the burning-out process, due to the use of air, thermodynamic NOx is inevitably generated in the process, and the subsequent denitration burden is increased.

Secondly, in the subsequent flue gas purification process, a quenching and semi-drying process is adopted in the prior art, alkali liquor is used for cooling the flue gas in the process, so that the temperature of the flue gas is reduced from 500 ℃ to below 200 ℃ within 1s, the process has extremely high control requirements, the temperature of the flue gas is rapidly reduced, the tower body corrosion caused by 'wet wall' due to excessive water injection cannot be caused, small-particle atomized alkali liquor used in the quenching process is generated by a high-quality atomizing nozzle under high pressure, and the atomizing nozzle is inevitably blocked due to mechanical friction or scaling in the use process, so that frequent maintenance and replacement are needed.

Thirdly, the alkali adopted by the quenching semi-dry method and the quenching dry method in the process route enters the bag-type dust remover in the form of particles, and the activated carbon is required to be sprayed to adsorb heavy metals, so that the concentration of the particles in the flue gas is artificially increased, and the treatment load of the bag-type dust remover is increased.

Disclosure of Invention

The invention mainly aims to realize elemental sulfur recovery in a high-sulfur hazardous waste treatment process.

In order to achieve the above object, a first aspect of the present invention relates to a method for recovering sulfur in the treatment of hazardous wastes with high sulfur content, characterized by comprising the steps of:

the high-sulfur hazardous waste is gasified and melted by plasma to generate H₂The synthesis gas of the S is mixed with the nitrogen,

the synthesis gas is subjected to one-stage or multi-stage wet deacidification, the synthesis gas is deacidified by alkali liquor to generate deacidification liquid dissolved with hydrosulphide,

the deacidification liquid generates elemental sulfur through catalytic oxidation.

Preferably, two-stage wet deacidification is used, and the first stage is deacidified by wet quenching.

Preferably, the liquid-gas ratio of the synthesis gas to the alkali liquor in the first-stage wet deacidification is 1-10L/m³The liquid-gas ratio of alkali liquor and synthetic gas in the second stage wet deacidification is 0.5-8L/m³。

Preferably, the deacidified liquid is subjected to solid-liquid separation to remove precipitates and then is subjected to catalytic oxidation.

Preferably, a step of purifying the elemental sulphur is included.

Preferably, part of the sensible heat of the synthesis gas is recycled before said wet deacidification.

Preferably, the method comprises the step of carrying out tail gas treatment on the synthesis gas left after wet deacidification.

Preferably, the tail gas treatment sequentially comprises the steps of wet dust removal, oxygen content analysis and combustion or storage of the synthesis gas according to the oxygen content analysis result.

When the oxygen content analysis result shows that the synthesis gas has the deflagration risk, the rest synthesis gas is combusted; when there is no risk of deflagration, the remaining synthesis gas is stored.

Preferably, the wet dust removal dust-containing removal liquid and the deacidification liquid are subjected to solid-liquid separation together.

Preferably, wet deacidification cools or maintains the syngas to below 40 ℃, and the deacidification liquid is also maintained at below 40 ℃.

Preferably, the elemental sulphur is melted and collected.

Preferably, in the step of melting the high-sulfur-content hazardous waste through plasma gasification, the temperature range of the plasma gasification melting is 1150-1600 ℃, the oxygen content is less than or equal to 1 percent, and the residence time of the synthesis gas exceeds 3 s.

Preferably, in the wet quenching deacidification, the pH value of the deacidification liquid is controlled to be between 8 and 13.

Preferably, the precipitate after solid-liquid separation and the high-sulfur hazardous waste are subjected to the plasma gasification melting reaction.

The second aspect of the present invention relates to a sulfur recovery apparatus in the treatment of hazardous waste with high sulfur content, comprising:

the plasma gasification melting furnace is used for gasifying and melting the hazardous waste with high sulfur content,

one or more stages of wet deacidification towers which are communicated with the plasma gasification melting furnace and used for carrying out wet quenching deacidification on the synthesis gas discharged by the plasma gasification melting furnace,

and the regeneration unit is communicated with the bottom of the wet quenching deacidification tower, and the deacidification liquid of the wet quenching deacidification tower is subjected to elemental sulfur regeneration in the regeneration unit.

Preferably, a crusher is included, and a feeder is arranged between the crushing outlet of the crusher and the inlet of the plasma gasification melting furnace, and is used for conveying the high-sulfur hazardous waste crushed by the crusher to the plasma gasification melting furnace.

Preferably, a waste heat boiler is further arranged between the plasma gasification melting furnace and the wet deacidification tower, and the plasma gasification melting furnace, the waste heat boiler and the wet quenching deacidification tower are sequentially communicated.

Preferably, a first solid-liquid separation device is further arranged between the wet type deacidification tower and the regeneration unit and used for removing precipitates in the deacidification liquid, the tower bottom of the wet type deacidification tower is communicated with the first solid-liquid separation device through a pipeline, and a liquid phase outlet of the first solid-liquid separation device is communicated with the regeneration tank through a pipeline.

Preferably, the first solid-liquid separation equipment adopts a filter press, the tower bottom of the wet deacidification tower is communicated with the inlet of the filter press, and the liquid phase outlet of the filter press is communicated with the regeneration unit.

Preferably, a two-stage wet type deacidification tower is adopted, and comprises a venturi wet type quenching deacidification tower and a washing tower, the plasma gasification melting furnace is communicated with an inlet of the venturi wet type quenching deacidification tower, a gas phase outlet of the venturi wet type quenching deacidification tower is communicated with an inlet of the washing tower, and the tower bottoms of the venturi wet type quenching deacidification tower and the washing tower are communicated with a regeneration unit.

Preferably, the tail gas treatment unit is communicated with the one-stage or multi-stage wet deacidification tower and is used for treating the synthesis gas discharged from the wet deacidification tower.

Preferably, the tail gas treatment unit comprises a wet dust collector, a flare and a storage tank, the wet deacidification tower is communicated with the wet dust collector and used for dedusting the synthesis gas discharged from the wet deacidification tower, and the dedusting equipment is switchably communicated with one of the flare or the storage tank.

Preferably, the wet dust collector is in switchable communication with the torch and the storage tank through a switchable pipeline, a switching valve is arranged on the switchable pipeline, and the dust collecting device is in communication with one of the torch and the storage tank through switching of the switching valve.

Preferably, the tail gas treatment unit further comprises a drying tower, and the switchable channel, the drying tower and the storage tank are sequentially communicated.

Preferably, an oxygen content analysis mechanism is arranged on one side of the switchable pipeline communicated with the dust removing device.

Preferably, the regeneration unit comprises a regeneration tank, the bottom of the wet deacidification tower is communicated with the regeneration tank, the bottom of the regeneration tank is provided with an air inlet, the upper part of the regeneration tank is provided with a foam tank, and the foam tank is used for collecting foam containing elemental sulfur.

Preferably, the regeneration unit further comprises a pregnant solution tank, the tower bottom of the wet deacidification tower is communicated with the pregnant solution tank, the pregnant solution tank is communicated with the regeneration tank, and the deacidification solution of the wet deacidification tower enters the regeneration tank after being collected by the pregnant solution tank.

Preferably, the regeneration tank is communicated with the wet deacidification tower, and the barren solution in the regeneration tank is refluxed to the wet deacidification tower.

Preferably, the device also comprises a purification unit which is communicated with the regeneration unit and is used for purifying the regenerated elemental sulfur.

Preferably, the purification unit comprises a second solid-liquid separation device and a sulfur melting kettle, the regeneration unit is communicated with an inlet of the second solid-liquid separation device, a solid phase outlet of the second solid-liquid separation device is communicated with the sulfur melting kettle, and the regenerated elemental sulfur and the deacidification liquid are separated by a centrifugal machine and enter the sulfur melting kettle to be melted.

Preferably, the second solid-liquid separation equipment adopts a centrifuge.

The sulfur recovery method and the device in the treatment of the high-sulfur hazardous waste can collect sulfur in the hazardous waste finally in the form of elemental sulfur, can effectively reduce the generation of dioxin and NOx, and provide a completely different technical route for the treatment of the high-sulfur hazardous waste. Meanwhile, in some optimized embodiments, the subsequent synthesis gas treatment process does not cause more burden on equipment, various resources and energy sources in the hazardous waste are properly arranged and utilized, and the equipment has the advantages of easiness in maintenance and more environment-friendly process.

Drawings

FIG. 1 is a process flow diagram of sulfur recovery in the treatment of high sulfur content hazardous waste in the example.

In the figure: 1. the system comprises a crusher, 2 a feeder, 3 a plasma gasification melting furnace, 4 a waste heat boiler, 5 a Venturi wet quenching deacidification tower, 6 a filter press, 7 a washing tower, 8 a wet dust remover, 9 a torch, 10 a drying tower, 11 a storage tank, 12 a rich liquid tank, 13 a regeneration tank, 14 a foam tank, 15 a centrifuge and 16 a sulfur melting kettle.

Detailed Description

The sulfur recovery device of the embodiment can recover sulfur in the high-sulfur hazardous waste in the form of elemental sulfur.

The unit in the invention refers to chemical unit equipment, and is a set of equipment and connection modes thereof for realizing one or more process steps in the complete process flow.

The communication between the devices in the invention can be realized through pipeline connection, pressure conveying machinery such as a pump, a compressor and the like can be added on the pipeline for assistance, and instruments and valves can be arranged on the pipeline according to requirements.

The sulfur recovery device mainly comprises:

a plasma gasification melting furnace 3 for gasifying and melting the high-sulfur hazardous waste,

one or more stages of wet deacidification towers which are communicated with the plasma gasification melting furnace and used for carrying out wet quenching deacidification on the synthesis gas discharged by the plasma gasification melting furnace,

and the regeneration unit is communicated with the bottom of the wet quenching deacidification tower, and the deacidification liquid of the wet quenching deacidification tower is subjected to elemental sulfur regeneration in the regeneration unit.

The high-sulfur hazardous waste is subjected to a plasma gasification melting reaction to generate H₂And (2) carrying out wet quenching deacidification on the synthesis gas of S, deacidifying the synthesis gas in a wet deacidification tower by using alkali liquor to generate deacidification liquid in which hydrosulphide is dissolved, and catalytically oxidizing the hydrosulphide in the deacidification liquid in a regeneration unit by using an oxygen-carrying catalyst to generate elemental sulphur. Compared with the existing plasma gasification melting process and sulfur recovery process, the device of the embodiment eliminates the secondary combustion chamber, and the sulfur in the dangerous waste is not combusted in the secondary combustion chamber to generate SO₂And/or SO₃But instead with H₂The form of S proceeds to the subsequent step, in the course of which not only H₂S is easier to obtain elemental sulfur through catalytic oxidation, and meanwhile, the process is also beneficial to fixing volatile heavy metals in high-sulfur-content hazardous wastes, so that the recovery of the volatile heavy metals becomes possible. In addition, the elimination of the secondary combustion chamber and its burn-out step also effectively reduces thermal NOx and dioxinThe method avoids the problem that a denitration link needs to be added in the traditional process, and has the advantages of low operation and maintenance cost, low investment cost and the like.

The plasma gasification melting furnace is further provided with a crusher 1, a feeder 2 is arranged between a crushing outlet of the crusher and an inlet of the plasma gasification melting furnace, and the feeder 2 is used for conveying the high-sulfur-content hazardous waste crushed by the crusher 1 to the plasma gasification melting furnace.

A waste heat boiler 4 is also arranged between the plasma gasification melting furnace 3 and the wet deacidification tower, and the plasma gasification melting furnace 3, the waste heat boiler 4 and the wet quenching deacidification tower are communicated in sequence.

In the embodiment, a two-stage wet deacidification tower is adopted, and comprises a venturi wet quenching deacidification tower 5 and a washing tower 7. The wet venturi quenching deacidification tower is generally composed of a contraction pipe, a throat pipe and a diffusion pipe. The alkali liquor for quenching deacidification is atomized into fine liquid drops under the action of higher gas velocity and shearing force at the throat, and fully contacts with synthesis gas to realize dust removal and deacidification. The washing tower is internally provided with two layers of fillers, a spray pipe is arranged above the two layers of fillers, the inlet of the washing tower is positioned below the fillers, and alkali liquor is sprayed out of the spray pipe to be fully contacted with synthesis gas so as to realize deacidification and dust removal. The gas phase outlet of the plasma gasification melting furnace is connected with the inlet of the waste heat boiler through a pipeline, the outlet of the waste heat boiler is communicated with the inlet of the Venturi wet quenching deacidification tower, and the gas phase outlet of the Venturi wet quenching deacidification tower is communicated with the inlet of the washing tower. The bottoms of the Venturi wet type quenching deacidification tower and the washing tower are communicated with a filter pressing inlet of a filter press, and a liquid phase outlet of the filter press is communicated with a regeneration unit.

The regeneration unit comprises a regeneration tank 13 and a pregnant solution tank 12, a liquid phase outlet of the filter press is communicated with the pregnant solution tank 12, the pregnant solution tank 12 is communicated with the regeneration tank 13, deacidification liquid of the wet-type deacidification tower enters the regeneration tank after being enriched by the pregnant solution tank 12, an air inlet is formed in the bottom of the regeneration tank, on one hand, air entering from the air inlet provides enough oxygen for catalytic oxidation, on the other hand, elemental sulfur generated by air floatation can be used for forming sulfur-containing foam on the liquid surface, a foam tank 14 is arranged on the upper portion of the regeneration tank 13, the foam tank 14 is used for collecting foam containing the elemental sulfur, the regeneration tank 13 is communicated with the wet-type deacidification tower, and lean liquid in the regeneration tank 13 flows back to each stage of the wet-type deacidification tower to deacidify the synthetic. The specific communication mode is as shown in fig. 1, the bottom of the regeneration tank 13 is respectively communicated with the contraction pipe of the venturi wet quenching deacidification tower 5 and the spray pipe arranged in the washing tower 7 through pipelines.

The sulfur melting device comprises a first solid-liquid separation device and a purification unit, wherein the first solid-liquid separation device comprises a first solid-liquid separation device body and a first sulfur melting kettle, the purification unit comprises a second solid-liquid separation device and a second sulfur melting kettle, the second solid-liquid separation device can adopt a centrifugal machine, a foam groove is communicated with an inlet of the centrifugal machine, sulfur-containing foam is conveyed to the centrifugal machine to centrifugally separate out elemental sulfur, a solid phase outlet of the centrifugal machine is communicated with the sulfur melting kettle, and the regenerated elemental sulfur and deacidified liquid are separated by the centrifugal machine and enter the sulfur.

The device is characterized by further comprising a tail gas treatment unit, wherein the tail gas treatment unit comprises a wet dust collector 8, a torch 9, a drying tower 10 and a storage tank 11, a gas phase outlet in the top of the washing tower 7 is communicated with the wet dust collector 8, the wet dust collector is communicated with the torch and the drying tower in a switchable mode through a switchable pipeline, a switching valve is arranged on the switchable pipeline, the dust removal equipment is communicated with one of the torch and the drying tower in a switchable mode through the switching of the switching valve, and the drying tower and the storage tank are communicated through pipelines.

When carrying out elemental sulfur and retrieving, high sulphur hazardous waste adds and breaks to the particle diameter and is less than 80mm in breaker 1, and the breakage can reduce the particle diameter of high sulphur hazardous waste, and more abundant reaction can be carried out to littleer granule to help there is more sulphur to be converted into H₂S, the solid left after filtration and generated in the subsequent process can also be conveyed to a crusher to be crushed together, and the crushed high-sulfur-content hazardous waste can be conveyed to the plasma gasification melting reaction furnace 3 through the feeder 2.

The crushed dangerous waste with high sulfur content is fed into a plasma gasification melting furnace 3 by a feeder 2 for gasification melting, the heat energy in the plasma gasification melting furnace 3 is generated by a plasma torch, and the medium gas of the plasma torch comprises air, nitrogen and H₂Natural gas, etc., the temperature range in the plasma gasification melting furnace 3 is 1150-1600 ℃, and the melting is carried outThen, vitrified slag and H-containing slag are formed₂S and heavy metal compound synthesis gas, and simultaneously controlling the oxygen content in the furnace to be less than or equal to 1%, wherein the residence time of the synthesis gas in the furnace exceeds 3S, the synthesis gas is discharged from the top of the furnace, and the vitrified slag is discharged from the bottom of the furnace.

Because the synthesis gas at the outlet of the plasma gasification melting furnace 3 is rich in a large amount of heat energy, the heat energy with the temperature of 200-1150 ℃ can be absorbed and utilized before wet quenching deacidification, and the synthesis gas is conveyed to the waste heat boiler 4 to absorb part of sensible heat.

The synthesis gas is transferred to a Venturi wet quenching deacidification tower 5 after heat exchange by a waste heat boiler 4 to be carried out wet quenching deacidification with alkali liquor, the dilute alkali liquor and the synthesis gas are carried out quenching deacidification in the wet quenching deacidification tower, and H in the synthesis gas is simultaneously treated₂S and other acidic substances (such as HCl) and particulate matters are removed, the temperature of the synthesis gas is rapidly reduced to below 40 ℃ from 200 ℃ in the quenching process, the temperature of the deacidification liquid is also kept below 40 ℃, and the liquid-gas ratio of the alkali liquor to the synthesis gas is 1-10L/m³. Using alkaline liquid such as Na₂CO₃Or K₂CO₃Alkali solution and H₂S reacts to form soluble hydrosulphide salts such as NaHS, KHS and precipitates. To adopt Na₂CO₃For example, the reaction formula is as follows:

Na₂CO₃+H₂S→NaHS+NaHCO₃

the heavy metal which is volatile in the synthesis gas is washed by a large amount of dilute alkali liquor and then is precipitated in the deacidification solution in the form of heavy metal sulfide, the heavy metal is beneficial to recycling after enrichment and pressure filtration, the heavy metal is easy to form precipitate at the tower bottom by adjusting the pH value of the deacidification solution to be between 8 and 13, and NaHS is dissolved in the deacidification solution. The heavy metal precipitation at the bottom of the tower and the solution dissolved with the hydrosulphide can be subjected to solid-liquid separation in the subsequent steps.

The residual synthesis gas in the Venturi wet type quenching deacidification tower enters a washing tower 7 for alkali washing, and the liquid-gas ratio of alkali liquor and the synthesis gas in the alkali washing is 0.5-8L/m³The temperature of the synthesis gas in alkaline washing is kept below 40 ℃, and the temperature of the deacidification liquid in the washing tower is also kept below 40 DEG CThe alkali liquor used for alkali washing can also be Na₂CO₃Or K₂CO₃Alkali solution and H₂S reacts to generate soluble hydrosulfide salt such as NaHS and KHS, and simultaneously heavy metal compounds in the synthesis gas precipitate and particles are further washed. By adjusting the pH value of the deacidification liquid in the washing tower 7 to be between 8 and 13 and allowing the deacidification liquid to be enriched in the form of precipitate at the bottom of the tower, the heavy metal precipitate at the bottom of the tower and the solution dissolved with the hydrosulphide can be subjected to solid-liquid separation in the subsequent steps.

The residual synthesis gas after alkaline washing is sent to a wet dust collector 8 from the top of a washing tower 7 to be dedusted by a removal liquid, fine particles (water drops, aerosol and the like) with the particle size of 0.5um in the synthesis gas are further removed, and the removal liquid containing dust can be discharged from an outlet at the bottom and then enter a filter press 6 to be filter-pressed together. The stripping liquid may be Na₂CO₃Or K₂CO₃. The use of the wet dust collector 8 instead of a bag dust collector can avoid the generation of secondary fly ash and also avoid secondary pollution caused by the replacement and disposal of the bag.

In the embodiment, when the oxygen volume content is larger than or equal to 2%, the gas at the outlet of the wet dust collector 8 is considered to have the deflagration risk, the gas at the outlet of the wet dust collector 8 is discharged to a torch 9 for combustion through a switching pipeline, and when the oxygen volume content is smaller than 2%, the gas is considered to have no deflagration risk, the gas at the outlet of the wet dust collector 8 is sent to a drying tower 10 to remove the moisture in the gas, so that the quality of the synthesis gas is increased, and the synthesis gas is pressurized to 10KPa and then is sent to a storage tank 11. The synthesis gas enters the synthesis gas removal point from the storage tank 11.

The heavy metal precipitate and the solution dissolved with the hydrosulfide generated in the wet deacidification process, the heavy metal precipitate and the solution dissolved with the hydrosulfide generated in the alkali washing process and the dust-containing desorption solution after dust removal are subjected to pressure filtration by a pressure filter 6 to obtain the product containing H₂The solution of S is filtered off into the following reaction step, while the heavy metal precipitates and the particles are pressed into a filter cake. The filter cake can be sent to the crusher 1 again for crushing and then is conveyed to the plasma gasification melting furnace for gasMelting and melting.

The filtrate obtained after filter pressing can be sent to the pregnant solution tank 12 to stay for 10-30 minutes and then enters the regeneration tank 13 to carry out sulfur regeneration reaction, air is pumped into the regeneration tank 13 from an air inlet, the sulfur hydride in the filtrate in the regeneration tank 13 generates elemental sulfur through the catalytic oxidation of an oxygen-carrying catalyst, and the reaction formula is as follows:

NaHS+0.5O₂→NaOH+S

simultaneously, the generated NaOH and NaHCO in the solution₃Reacting and regenerating Na capable of being used for quenching deacidification and alkali washing₂CO₃。

NaOH+NaHCO₃→Na₂CO₃+H₂O

Meanwhile, the air pumped into the regeneration tank 13 has a bubbling effect, elemental sulfur is floated to the upper part of the liquid by bubbling to form sulfur-containing foams, the sulfur-containing foams are collected by a foam tank 14 arranged at the top of the regeneration tank 13 and then enter a centrifugal machine 15 for centrifugal separation, and the separated elemental sulfur enters a sulfur melting kettle 16 for melting and then is collected into sulfur products. The regenerated lean solution (mainly containing regenerated Na) after the regeneration reaction in the regeneration tank 13₂CO₃) It is returned as a recycle liquid to the wet quench deacidification tower 5 and the scrubber tower 7 for washing, deacidification and to the wet dust collector 8 for use as a stripping liquid.

The embodiments of the present invention are merely illustrative, and not restrictive, of the scope of the claims, and other substantially equivalent alternatives may occur to those skilled in the art and are within the scope of the present invention.