CN115180753B

CN115180753B - Method for catalyzing and desalting SRG washing wastewater and system for catalyzing and desalting SRG washing wastewater

Info

Publication number: CN115180753B
Application number: CN202110359165.8A
Authority: CN
Inventors: 杨本涛; 李小龙; 康建刚
Original assignee: Zhongye Changtian International Engineering Co Ltd
Current assignee: Zhongye Changtian International Engineering Co Ltd
Priority date: 2021-04-02
Filing date: 2021-04-02
Publication date: 2023-12-29
Anticipated expiration: 2041-04-02
Also published as: CN115180753A

Abstract

The invention discloses a method for catalyzing and desalting SRG washing wastewater and a system for catalyzing and desalting SRG washing wastewater. The sulfur-containing activated carbon is obtained by adopting activated carbon powder contained in SRG washing wastewater as a carrier, adopting acidolysis of thiosulfate ions contained in the SRG wastewater as a sulfur source and carrying out sedimentation adsorption at normal temperature and normal pressure. Then the sulfur-containing active carbon is used as a catalyst, and the disproportionation reaction of the high-concentration bisulfide ions can be realized at about 50 ℃ and the sulfur resource can be recovered and obtained. The invention can recycle sulfur while treating the wastewater, realizes the recycling treatment of the wastewater, and has no secondary pollution. Therefore, the catalyst for the disproportionation and desulfurization of the bisulfide ions in the SRG washing wastewater by using the sulfur-containing activated carbon has wide market prospect and economic benefit.

Description

Method for catalyzing and desalting SRG washing wastewater and system for catalyzing and desalting SRG washing wastewater

Technical Field

The invention relates to an SRG washing wastewater treatment technology, in particular to a method for catalyzing and desalting SRG washing wastewater and a system for catalyzing and desalting the SRG washing wastewater, and belongs to the technical fields of SRG flue gas washing wastewater treatment and sulfur resource recovery.

Background

The sintering flue gas in the steel industry adopts an active carbon method to carry out desulfurization and denitrification to carry out a flue gas purification process, and sulfur dioxide gas collected by active carbon is concentrated and released and then is sent to a sulfur resource workshop to produce sulfur resources. The flue gas enriched with sulfur dioxide gas is called sulfur-rich gas (SRG flue gas) for short, and the gas can be prepared into sulfur resources meeting the national standard through the procedures of purification, drying, conversion, absorption and the like, and the resource recovery value is high. However, impurities and harmful elements in the flue gas can be simultaneously washed and enter acid washing wastewater in a purification process in the sulfur resource production process, and part of sulfur dioxide gas in the flue gas can be absorbed by water vapor and brought into the wastewater.

Generally, the SRG flue gas scrubbing wastewater tends to be acidic because the acidic species in the SRG gas are greater than the basic species. When cyanide and derivatives thereof exist in the front-end flue gas, the cyanide and derivatives thereof enter SRG gas and are finally dissolved in the acidic washing wastewater, so that the alkalinity of the wastewater (such as hydrolysis of cyanic acid to generate ammonia nitrogen) is increased, and the acidic washing wastewater is neutral. Since the acidic washing wastewater is neutral, a large amount of SO in SRG gas can be caused ₂ The acid gas dissolves, causing a dramatic increase in bisulphite in the wastewater. The detection result shows that the concentration of the hydrogen sulfite in the acid washing wastewater generated by the cyanide-free SRG gas washing is 2-5 g/L, and the concentration of the hydrogen sulfite in the acid washing wastewater generated by the cyanide-containing SRG gas washing is 240-300 g/L. The acidic washing wastewater containing the bisulfide with high concentration has huge treatment difficulty if entering a subsequent wastewater treatment system. On one hand, the alkali consumption is increased sharply, so that the waste of liquid alkali is caused, and the wastewater discharge amount is increased; in addition, sodium sulfite is formed to crystallize and separate out during the alkali adding process, which results in system blocking and paralysis.

Sulfur is an oxygen group simple substance nonmetallic solid, is an important chemical raw material, and is widely used for producing various chemical products, gunpowder, matches, pigments and medicinal products. Powdered sulfur is agriculturally useful as an insecticide and bactericide. Sulfur is mainly derived from natural sulfur deposit extraction and recovery of sulfur from natural gas, coal gas and industrial waste gas. With the expansion of sulfur demand, the recovery of sulfur from waste gas or wastewater is becoming an important source of sulfur.

The liquid phase disproportionation sulfur production method is to utilize the characteristic that sulfur element in bisulphite is in an intermediate valence state, and disproportionation is carried out under the conditions of high temperature and catalyst, so that the recovery of elemental sulfur is realized. Aiming at the defects that the concentration of hydrogen sulfite in wastewater is high, direct alkali addition can cause crystallization of a wastewater system and cause blockage. The use of "acid stripping" and "precipitation" has been reported earlier, but these methods have been somewhat inadequate. The method comprises the following steps:

acidification and blowing off method: the hydrogen sulfite can be changed into sulfur dioxide to escape under the acidic condition, so that the concentration of the hydrogen sulfite is reduced. The reactions involved are: HSO (high speed oxygen) ₃ ^- +H ⁺ →H ₂ SO ₃ ；H ₂ SO ₃ +air→H ₂ O+SO ₂ And ≡. However, the method needs to add an acid solution, the total water amount is increased, and the addition amount of the acid solution is larger. In addition, the method utilizes strong acid to prepare weak acid, and the total salt content can be reduced by 50% at most.

Precipitation method: the sulfate is removed by utilizing the property that the bisulfate and the metal cations form sulfate, such as adding calcium oxide, magnesium oxide, ferrous sulfate, ferric chloride, ferrous chloride, ferric nitrate and ferrous nitrate. The reactions involved are: SO (SO) ₃ ^2- +precipitant M.fwdarw.MSO ₃ And ∈. This process produces a large amount of solid slag and metal salts are generally expensive.

Disproportionation method: such as chinese patent documents 201210391355.9, 201210392392.1, 201711078170.1. Based on the property that the bisulfide can be disproportionated into elemental sulfur and sulfate radical, the 1/3 reduction of the bisulfide is realized under the condition of not consuming additional substances. The reactions involved are: 3HSO ₃ ^- →S+2SO ₄ ^2- +H ⁺ +H ₂ O. The temperature of the direct reaction was > 160 ℃. The addition of the catalyst can reduce the reaction temperature: such asSelenium is added, so that the reaction temperature can be reduced to 80-100 ℃; iodine is added and under the photocatalysis effect, the method can be carried out at normal temperature. But because selenium and iodine are expensive, the possibility of industrial application is not provided. In the method, the disproportionation method has the advantages of no additional consumption of substances, no increase of water quantity and the like. Disproportionation of bisulphite by catalytic means to recover sulphur is a low cost operation. However, the process has not been widely popularized due to the high price of the catalyst. Therefore, the finding of a low-cost and high-efficiency bisulphite disproportionation catalyst for recycling the SRG washing wastewater has important significance.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for catalyzing and desalting SRG washing wastewater and a system for catalyzing and desalting the SRG washing wastewater. The sulfur-containing activated carbon is obtained by adopting activated carbon powder contained in SRG washing wastewater as a carrier and thiosulfate ions contained in the SRG wastewater as a sulfur source, and performing sedimentation adsorption at normal temperature and normal pressure. And then the sulfur-containing active carbon is used as a catalyst, and the disproportionation reaction recovery of high-concentration bisulfide ions can be realized under the condition of lower temperature (about 50 ℃) to obtain sulfur resources. On one hand, the salt content in the SRG washing wastewater is reduced, and on the other hand, the purpose of recycling sulfur is realized; the consumption of liquid alkali is greatly reduced, and the consumption of liquid alkali can be reduced by about 60 percent through a comparison test. The sulfur-containing activated carbon used in the invention has the advantages of simple preparation process, easily available raw materials, low price and large-scale application prospect, and the prepared sulfur-containing activated carbon can be recycled. In addition, the invention can recycle sulfur while treating the wastewater, realize the recycling treatment of the wastewater and avoid secondary pollution. Therefore, the catalyst for the disproportionation and desulfurization of the bisulfide ions in the SRG washing wastewater by using the sulfur-containing activated carbon has wide market prospect and economic benefit.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

according to a first embodiment of the present invention, a method for catalytic desalination of SRG wash wastewater is provided.

A method for catalytic desalination of SRG wash wastewater, the method comprising the steps of:

1) Separating out the activated carbon powder in the SRG washing wastewater, taking part of the SRG washing wastewater, adding acid for acidification, and then mixing the activated carbon powder with the part of the SRG washing wastewater after acidification, and carrying out sedimentation adsorption. Finally, the sulfur-containing activated carbon and the desulfurization wastewater are obtained after solid-liquid separation.

2) And uniformly mixing the desulfurization wastewater and the rest SRG washing wastewater, and then adding sulfur-containing activated carbon to perform catalytic disproportionation reaction.

3) Continuously monitoring the pH value of the reaction system in the step 2) until the pH value changes to the pH set value. Then solid-liquid separation is carried out to obtain filtrate.

4) And (3) continuously heating the filtrate obtained in the step (3) to react until precipitation is generated and clear supernatant appears, and filtering to obtain sulfur and SRG washing wastewater after desalting.

Preferably, in step 1), the SRG wash wastewater is a cyanide-containing SRG wash wastewater.

Preferably, in step 1), the partial SRG wash wastewater is used in an amount such that the numerical ratio in the partial SRG wash wastewater is from 0.05 to 0.5:1, preferably from 0.1 to 0.3:1, more preferably from 0.15 to 0.25:1.

Preferably, in step 1), the acid is one or more of hydrochloric acid, sulfuric acid, nitric acid, nitrous acid, and phosphoric acid. Preferably sulfuric acid.

Preferably, in step 2), the temperature of the disproportionation reaction is 40-80 ℃, preferably 45-70 ℃, more preferably 50-60 ℃. The disproportionation reaction time is 0.3 to 10 hours, preferably 0.5 to 8 hours, more preferably 0.8 to 5 hours.

Preferably, in step 3), the pH set point is < 3, preferably the pH set point is < 2.5, more preferably the pH set point is < 2.

Preferably, in step 4), the reaction temperature of the heating reaction is 50 to 120 ℃, preferably 60 to 110 ℃, more preferably 70 to 100 ℃.

Preferably, the step 1) specifically comprises: the activated carbon powder in the SRG washing wastewater is separated for standby, and then a part of the SRG washing wastewater is taken, and acid (such as sulfuric acid) is added into the part of the SRG washing wastewater to adjust the pH to be less than 3 (preferably, the pH is less than 2). Then adding the activated carbon powder into the acidified SRG wastewater for sedimentation adsorption (the adsorption time is 0.3-5h, preferably 0.5-3 h). And (3) carrying out solid-liquid separation after the adsorption is finished to obtain solid and filtrate, and drying the obtained solid to obtain the sulfur-containing activated carbon.

In general, the sulfur-bearing active carbon has a sulfur-bearing amount of 1.6 to 16g, preferably 3.2 to 9.6g, more preferably 4.8 to 8g, per gram of active carbon.

Preferably, the sulfur-containing activated carbon is an activated carbon subjected to multiple precipitation adsorption, preferably 2 to 10 times, more preferably 3 to 5 times. The SRG wash waste water used for each settling adsorption is derived from the original SRG wash waste water.

Preferably, the step 2) specifically comprises: and firstly, uniformly mixing the filtrate obtained after the solid-liquid separation in the step 1) with the rest SRG washing wastewater. Then adding sulfur-containing active carbon, heating to 40-80 ℃ (preferably 50-60 ℃) to perform disproportionation reaction for 0.3-10h (preferably 0.5-8 h), and performing step 3 after obtaining a disproportionation reaction system.

Preferably, the step 3) specifically comprises: continuously monitoring the pH value of the disproportionation reaction system in the step 2), filtering after the pH value of the disproportionation reaction system is lower than 3 (preferably, the pH value is lower than 2), separating sulfur-containing active carbon and obtaining filtrate. The sulfur-containing activated carbon is returned to the step 2) and is continuously used as a catalyst, and the filtrate is subjected to the step 4).

Preferably, the step 4) specifically comprises: the filtrate obtained in step 3) is further heated to 50-120 c (preferably 70-100 c) for reaction until sulphur precipitation occurs and a relatively clear supernatant is obtained. And separating out sulfur precipitate, drying to obtain elemental sulfur, and discharging supernatant after the sulfur precipitate is separated out after being treated by a wastewater aftertreatment system.

According to a second embodiment of the present invention, a method for catalytic desalination of SRG wash wastewater is provided.

A system for catalytic desalination of SRG wash wastewater or a system for catalytic desalination of SRG wash wastewater for use in the method of the first embodiment, the system comprising a wastewater conveying device, a carbon-liquid separation tank, a sedimentation adsorption tank, a catalytic disproportionation tank, and a colloid destabilization tank. The wastewater conveying device is communicated with a feed inlet of the carbon-liquid separation tank. The carbon-liquid separation tank, the sedimentation adsorption tank, the catalytic disproportionation tank and the colloid destabilization tank are sequentially connected in series.

Preferably, the system further comprises an acidification tank located between the carbon-liquid separation tank and the sedimentation adsorption tank. The water outlet of the carbon-liquid separation tank is communicated with the water inlet of the acidification treatment tank through a first pipeline. The water outlet of the acidification treatment tank is communicated with the water inlet of the sedimentation adsorption tank through a second pipeline. An acid liquid conveying pipeline is connected to an acid inlet of the acidification treatment tank.

Preferably, the system further comprises an activated carbon buffer bin. The active carbon buffering bin is positioned between the carbon-liquid separation tank and the sedimentation adsorption tank. The discharge port of the carbon-liquid separation tank is communicated with the feed port of the active carbon buffering bin through a first material conveying device. And a discharge port of the charcoal buffering bin is communicated with a feed port of the sedimentation adsorption tank through a second material conveying device.

Preferably, the system further comprises a mixing tank. The liquid mixing pool is positioned between the sedimentation adsorption pool and the catalytic disproportionation pool. And the water outlet of the sedimentation adsorption tank is communicated with the water inlet of the liquid mixing tank through a third pipeline. The water outlet of the carbon-liquid separation tank is also communicated with the water inlet of the liquid mixing tank through a fourth pipeline. The water outlet of the liquid mixing pool is communicated with the water inlet of the catalytic disproportionation pool through a fifth pipeline.

Preferably, the system further comprises a sulfur-containing activated carbon buffer bin. The sulfur-containing active carbon buffer bin is positioned between the sedimentation adsorption tank and the catalytic disproportionation tank. And a discharge port of the sedimentation adsorption tank is communicated with a feed port of the sulfur-containing active carbon buffering bin through a third material conveying device. And a discharge port of the sulfur-containing active carbon buffering bin is communicated with a feed port of the catalytic disproportionation tank through a fourth material conveying device.

Preferably, the discharge port of the sulfur-containing activated carbon cache bin is also communicated with the feed port of the sedimentation adsorption tank through a fifth material conveying device.

Preferably, the system further comprises a first solid-liquid separation device. The first solid-liquid separation device is positioned between the catalytic disproportionation tank and the colloid destabilization tank. And a discharge port of the catalytic disproportionation tank is connected with a feed port of the first solid-liquid separation device through a sixth material conveying device. The water outlet of the first solid-liquid separation device is communicated with the water inlet of the colloid destabilizing pond through a sixth pipeline.

Preferably, the discharge port of the first solid-liquid separation device is also communicated with the feed port of the catalytic disproportionation tank through a seventh material conveying device.

Preferably, the system further comprises a second solid-liquid separation device. And a feed inlet of the second solid-liquid separation device is communicated with a discharge outlet of the colloid destabilizing pond through an eighth material conveying device. The discharge port of the second solid-liquid separation device is connected with a ninth material conveying device, and the discharge port of the second solid-liquid separation device is connected with a seventh pipeline.

Preferably, the system further comprises a sulfur drying device. And a feed inlet of the sulfur drying device is communicated with a discharge outlet of the second solid-liquid separation device through a ninth material conveying device. And the air inlet of the sulfur drying device is connected with a protective gas conveying pipeline.

Preferably, the system further comprises a wastewater post-treatment system. The water inlet of the wastewater aftertreatment system is communicated with the water outlet of the second solid-liquid separation device through a seventh pipeline.

Preferably, the system further comprises a sulfur storage bin. The sulfur storage bin is communicated with a discharge port of the sulfur drying device through a tenth material conveying device.

In the prior art, because the acidic substances in the SRG gas are larger than the alkaline substances, the SRG flue gas washing wastewater tends to be acidic. When cyanide and derivatives thereof exist in the front-end flue gas, the cyanide and derivatives thereof enter SRG gas and are finally dissolved in the acidic washing wastewater, so that the alkalinity of the wastewater (such as hydrolysis of cyanic acid to generate ammonia nitrogen) is increased, and the acidic washing wastewater is neutral. Since the acidic washing wastewater is neutral, a large amount of SO in SRG gas can be caused ₂ The acid gas dissolves, causing a dramatic increase in bisulphite in the wastewater. The detection result shows that the acid washing waste generated by cyanide-free SRG gas washingThe concentration of the hydrogen sulfite in the water is 2-5 g/L, and the concentration of the hydrogen sulfite in the acid washing wastewater generated by washing the cyanide-containing SRG gas is 240-300 g/L. The acidic washing wastewater containing the bisulfide with high concentration has huge treatment difficulty if entering a subsequent wastewater treatment system. On one hand, the alkali consumption is increased sharply, so that the waste of liquid alkali is caused, and the wastewater discharge amount is increased; in addition, sodium sulfite is formed to crystallize and separate out during the alkali adding process, which results in system blocking and paralysis. The existing acidification stripping method, precipitation method and disproportionation method have the problems of low treatment efficiency and high input cost, and are not beneficial to large-scale industrialized popularization and application.

At present, sulfur mainly comes from ore deposit extraction of natural sulfur and recovery of sulfur from natural gas, coal gas and industrial waste gas. With the expansion of sulfur demand, the recovery of sulfur from waste gas or wastewater is becoming an important source of sulfur. The liquid phase disproportionation sulfur production method is characterized in that the characteristic that the sulfur element in the bisulphite is in an intermediate valence state is utilized, and the disproportionation is carried out under the conditions of high temperature (for example, the temperature at which the bisulphite directly carries out disproportionation reaction is more than 160 ℃) and a catalyst, so that the recovery of elemental sulfur is realized. However, the existing catalysts such as selenium and iodine are expensive, and are not suitable for industrial mass production and application at present.

In the present invention, the inventors of the present application have found through studies that, with respect to the high bisulfite-containing property of cyanide-containing SRG wastewater, disproportionation of high concentration of bisulfite can be achieved under low temperature (around 50 ℃) conditions when elemental sulfur and activated carbon coexist. The sulfur resource is obtained by disproportionation reaction recovery of high-concentration bisulfide ions by adopting sulfur-containing active carbon as a catalyst. On one hand, the salt content in the SRG washing wastewater is reduced, and on the other hand, the purpose of recycling sulfur is realized; greatly reduces the liquid alkali consumption in the subsequent wastewater treatment process, and the liquid alkali consumption can be reduced by about 60 percent through a comparison test. The sulfur-containing activated carbon used in the invention has the advantages of simple preparation process, easily available raw materials, low price and large-scale application prospect, and the prepared sulfur-containing activated carbon can be recycled.

In the invention, under the catalysis of sulfur-containing activated carbon, hydrogen ions and sulfite ions in SRG washing wastewater undergo catalytic disproportionation reaction. Namely, the bisulphite can undergo disproportionation reaction under the catalysis of sulfur-containing activated carbon at the temperature of 40-80 ℃ (preferably 50-60 ℃), and the S (IV) is disproportionated into S (0) and S (VI). The pH of the solution will always decrease during this reaction. When the pH of the solution is reduced to below 3 (preferably to below 2), the catalyst is filtered and separated (the separated sulfur-containing catalyst can be recycled after being dried), so that the investment cost of the catalyst is greatly reduced. The remaining solution is a sulfur colloid, and the colloid is destabilized by continuing to heat (e.g., to 50-120 ℃, preferably to 70-100 ℃) to finally form sulfur particles. Separating out sulfur particle precipitate and drying to obtain elemental sulfur. The invention can recycle sulfur while reducing the salt content of the washing wastewater, realizes the resource utilization and treatment of the wastewater, and has no secondary pollution. The reaction process for disproportionation of S (IV) into S (0) and S (VI) is shown below: the sulfur-containing activated carbon is used as a catalyst for catalytic disproportionation:

generally, the sulfur-containing activated carbon is prepared by adopting high-quality activated carbon as base carbon and adopting a special process, and is mainly used for mercury removal in mercury-containing gas mercury removal devices such as natural gas/coal gas and the like. In the invention, sulfur-containing activated carbon is prepared and obtained by an adsorption method, which comprises the following specific steps: because the SRG washing wastewater contains a large amount of thiosulfate radical, acidolysis can be carried out under the acidic condition to release colloid sulfur, the SRG washing wastewater which is partially subjected to acidification treatment and contains thiosulfate radical ions is used as a sulfur source, and activated carbon contained in the SRG washing wastewater is used as an adsorption carrier (the activated carbon can be additionally added). The activated carbon is mixed with the SRG washing wastewater containing thiosulfate ions after acidolysis (generally, the total adding amount of the thiosulfate ions is larger than that of the activated carbon, for example, the numerical ratio is 0.05-0.5:1, preferably 0.1-0.3:1, more preferably 0.15-0.25:1), and the acid subjected to acidification is sulfuric acid and/or sulfurous acid, and when the thiosulfate ions meet the acid, the colloidal sulfur is released. As same as During acidolysis, active carbon powder or active carbon particles are mixed in the solution, so that the colloid sulfur separated out by acidolysis of thiosulfate ions can be adsorbed into the active carbon powder or active carbon particles to form sulfur-containing active carbon through the adsorption effect (sedimentation adsorption process) of the active carbon powder or active carbon particles. The specific reaction formula is as follows: acidolysis of thiosulfate ions under acidic conditions: s is S ₂ O ₃ ^2- +H ⁺ S (sulphur colloid) +HSO ₃ ^- 。

In the present invention, the compounding process of the sulfur-containing activated carbon is as follows: S+AC→S@AC. (AC refers to activated carbon). The sulfur-containing activated carbon has the advantages of simple preparation process, low price, wide source, easy separation and recovery and long service life.

In the invention, sulfur-containing active carbon is added into the waste water containing bisulphite to catalyze and disproportionate bisulphite ions, the reaction temperature is controlled to be about 50 ℃, and after a period of reaction, the solution becomes light yellow. Filtering to separate sulfur-containing active carbon, and continuing to react the residual filtrate at 70-100 ℃ until sulfur precipitation is generated and clear supernatant is obtained, namely, the reaction is finished (the residual filtrate is sulfur colloid, and then, heating reaction is continued to destabilize the colloid to form sulfur particles).

In the invention, SRG washing wastewater is conveyed into a carbon-liquid separation tank through a wastewater conveying device, and active carbon powder in the SRG wastewater is separated after the carbon-liquid separation tank is subjected to standing settlement. At the same time, extracting part of supernatant fluid of the carbon-liquid separation tank into an acidification treatment tank, adding acid (sulfuric acid and/or sulfurous acid) to adjust the pH of wastewater in the acidification treatment tank to be less than 3 (preferably pH is less than 2), and adding activated carbon powder (new activated carbon powder can be additionally added according to working condition requirements) separated from SRG wastewater before sedimentation adsorption. And separating the sulfur-containing active carbon adsorbed with sulfur for standby after the adsorption is completed. And the wastewater from which the sulfur-containing activated carbon is separated is conveyed into a liquid mixing tank to be mixed with the original SRG wastewater.

In the invention, the sulfur-containing activated carbon after sedimentation adsorption can be directly used for catalyzing the disproportionation reaction of the bisulphite in the SRG washing wastewater. In general, in order to make the catalytic effect of the sulfur-containing activated carbon better, it is generally necessary to subject the sulfur-containing activated carbon to a multiple-settling adsorption treatment. That is, in the present invention, a plurality of sedimentation adsorption tanks may be simultaneously provided, and then the sulfur-containing activated carbon is subjected to adsorption treatment in each of the sedimentation adsorption tanks one by one. The wastewater of each sedimentation adsorption tank is from original SRG washing wastewater, and the wastewater after sedimentation adsorption is conveyed to a liquid mixing tank to be mixed with the rest SRG washing wastewater. (the remaining part of the SRG washing wastewater refers to the original SRG washing wastewater after removing all SRG wastewater required for sedimentation adsorption).

In the invention, the liquid mixing tank is used for fully mixing the settled and adsorbed SRG wastewater and the rest SRG wastewater, on one hand, the liquid mixing tank is used for intensively realizing the catalytic disproportionation of bisulphite in the two wastewater, and on the other hand, the liquid mixing tank is also used for regulating the acidity of the mixed wastewater to be consistent and the concentration of the contained bisulphite ions to be balanced. And then conveying the uniformly mixed wastewater to a catalytic disproportionation tank for catalytic disproportionation reaction.

In the invention, SRG washing wastewater containing bisulfide ions and active carbon with content are simultaneously put into a catalytic disproportionation tank, and then heated to 40-80 ℃ (preferably 50-60 ℃) for disproportionation reaction, so that the bisulfide ions in the wastewater undergo disproportionation reaction under the catalysis of the sulfur-containing active carbon. Thereby realizing the purpose of reducing the bisulphite content of the SRG washing wastewater. SRG wastewater with reduced bisulfite content is discharged into a wastewater post-treatment system for subsequent purification treatment.

In the invention, sulfur colloid generated by the disproportionation reaction of the bisulfide ions in the catalytic disproportionation tank is recycled to the colloid destabilization tank for further heating (for example, heating to 50-120 ℃, preferably heating to 70-100 ℃) destabilization reaction, so that sulfur simple substance with economic value is prepared and recycled.

In the invention, the waste water conveying device is a waste water conveying pipeline. The caliber is 0.1-100m, preferably 0.3-80m, more preferably 0.8-50 m, still more preferably 1-30m.

In the invention, the number of the wastewater conveying device, the carbon-liquid separation tank, the sedimentation adsorption tank, the catalytic disproportionation tank and the colloid destabilization tank is respectively and independently 1-100, preferably 2-80, preferably 3-50, and more preferably 5-30.

In the invention, the volumes of the carbon-liquid separation tank, the sedimentation adsorption tank, the catalytic disproportionation tank and the colloid destabilization tank are respectively and independently 1-100000000m ³ Preferably 2-50000000m ³ More preferably 3-10000000m ³ More preferably 5-1000000m ³ Further preferably 10 to 500000m ³ 。

In the present invention, the sulfur loading per gram of activated carbon is the sulfur content per unit mass of activated carbon in the sulfur-containing activated carbon after passing through the embodiments provided herein. I.e., the mass ratio of sulfur to activated carbon in the sulfur-containing activated carbon.

Compared with the prior art, the beneficial technical effects of the invention are as follows:

1. the invention adopts the active carbon contained in the SRG wastewater as an adsorption carrier, and utilizes the sulfur colloid released after acidolysis of thiosulfate ions in the wastewater as a sulfur source, and has stronger adsorption effect through the active carbon powder or the active carbon particles. So that the colloid sulfur separated out by the acidolysis of the thiosulfate ions enters the activated carbon powder or the activated carbon particles to form the sulfur-containing activated carbon. The sulfur-containing activated carbon with excellent catalytic performance is prepared by changing waste into valuables under normal temperature and normal pressure through simple process conditions.

2. The sulfur-containing active carbon synthesized by the method is used as a catalyst for the disproportionation reaction of the bisulfites (or the acidic solution of the sulfites), and has the advantages of low price, wide sources, easy separation and recovery and long service life compared with the existing catalyst. And the sulfur-carrying activated carbon is used as a catalyst, so that elemental sulfur can be prepared and recovered at a lower temperature (about 50 ℃), the engineering application prospect is wide, and the method has great economic benefit.

3. The invention innovatively adopts sulfur-containing activated carbon for the catalytic disproportionation reaction of bisulphite in the cyanide-containing SRG washing wastewater, thereby realizing the low-temperature catalytic disproportionation. The method can recycle sulfur while reducing the salt content of the washing wastewater, realizes the resource utilization and treatment of the wastewater, and has no secondary pollution.

4. Based on the property of producing sulfur by the hydrogen sulfite disproportionation, the invention creatively provides a new technology for desalting and desulfurizing by a disproportionation method, realizes the reduction of the salt content in the wastewater and the recovery of sulfur resources, and greatly reduces the consumption of liquid alkali in the subsequent wastewater treatment process (about 60% can be reduced by a comparison test). Provides a new way for the treatment and resource utilization of SRG washing wastewater.

Drawings

FIG. 1 is a flow chart of a method for catalytic desalination of SRG washing wastewater.

FIG. 2 is a schematic diagram of a system for catalytic desalination of SRG wash wastewater according to the present invention.

FIG. 3 is an overall block diagram of a system for catalytic desalination of SRG wash wastewater according to the present invention.

FIG. 4 is a graph comparing the post-alkali consumption of wastewater treated by the method of the present invention with the post-alkali consumption of wastewater of the prior art.

Reference numerals: 1: a waste water conveying device; 2: a carbon-liquid separation tank; 3: a sedimentation adsorption tank; 4: a catalytic disproportionation tank; 5: a colloid destabilizing pool; 6: an acidification treatment tank; 601: an acid liquid conveying pipeline; 7: an active carbon buffering bin; 8: a liquid mixing pool; 9: a sulfur-containing active carbon buffer bin; 10: a first solid-liquid separation device; 11: a second solid-liquid separation device; 12: a sulfur drying device; 1201: a shielding gas delivery conduit; 13: a wastewater post-treatment system; 14: a sulfur storage bin; l1: a first pipe; l2: a second pipe; l3: a third conduit; l4: a fourth conduit; l5: a fifth pipe; l6: a sixth conduit; l7: a seventh pipe; s1: a first material conveying device; s2: a second material conveying device; s3: a third material conveying device; s4: a fourth material conveying device; s5: a fifth material conveying device; s6: a sixth material conveying device; s7: a seventh material conveying device; s8: an eighth material conveying device; s9: a ninth material conveying device; s10: tenth material conveying device.

Detailed Description

The following examples illustrate the technical aspects of the invention, and the scope of the invention claimed includes but is not limited to the following examples.

Preferably, in step 1), the partial SRG wash wastewater is used in an amount such that the numerical ratio of the molar amount of thiosulfate in the partial SRG wash wastewater (moL) to the weight of activated carbon (g) is 0.05-0.5:1, preferably 0.1-0.3:1, more preferably 0.15-0.25:1.

Preferably, the sulfur-containing activated carbon is activated carbon after multiple sedimentation and absorption, preferably 2 to 10 times, more preferably 3 to 5 times. The SRG wash waste water used for each settling adsorption is derived from the original SRG wash waste water.

Example 1

As shown in fig. 2, the system for catalytic desalination of SRG washing wastewater comprises a wastewater conveying device 1, a carbon-liquid separation tank 2, a sedimentation adsorption tank 3, a catalytic disproportionation tank 4 and a colloid destabilization tank 5. The wastewater conveying device 1 is communicated with a feed inlet of the carbon-liquid separation tank 2. The carbon-liquid separation tank 2, the sedimentation adsorption tank 3, the catalytic disproportionation tank 4 and the colloid destabilization tank 5 are sequentially connected in series.

Example 2

Example 1 is repeated as shown in fig. 3, except that the system further comprises an acidification tank 6, said acidification tank 6 being located between the carbon liquid separation tank 2 and the sedimentation adsorption tank 3. The water outlet of the carbon-liquid separation tank 2 is communicated with the water inlet of the acidification treatment tank 6 through a first pipeline L1. The water outlet of the acidification treatment tank 6 is communicated with the water inlet of the sedimentation adsorption tank 3 through a second pipeline L2. An acid liquid conveying pipeline 601 is connected to an acid inlet of the acidification treatment tank 6.

Example 3

Example 2 was repeated except that the system also included an activated carbon surge bin 7. The active carbon cache bin 7 is positioned between the carbon-liquid separation tank 2 and the sedimentation adsorption tank 3. The discharge port of the carbon-liquid separation tank 2 is communicated with the feed port of the active carbon cache bin 7 through a first material conveying device S1. The discharge port of the charcoal buffering bin 7 is communicated with the feed port of the sedimentation adsorption tank 3 through a second material conveying device S2.

Example 4

Example 3 is repeated except that the system further comprises a mixing tank 8. The liquid mixing pool 8 is positioned between the sedimentation adsorption pool 3 and the catalytic disproportionation pool 4. The water outlet of the sedimentation adsorption tank 3 is communicated with the water inlet of the liquid mixing tank 8 through a third pipeline L3. The water outlet of the carbon-liquid separation tank 2 is also communicated with the water inlet of the liquid mixing tank 8 through a fourth pipeline L4. The water outlet of the liquid mixing tank 8 is communicated with the water inlet of the catalytic disproportionation tank 4 through a fifth pipeline L5.

Example 5

Example 4 was repeated except that the system also included a sulfur-containing activated carbon surge bin 9. The sulfur-containing activated carbon cache bin 9 is positioned between the sedimentation adsorption tank 3 and the catalytic disproportionation tank 4. And a discharge port of the sedimentation adsorption tank 3 is communicated with a feed port of the sulfur-containing active carbon cache bin 9 through a third material conveying device S3. The discharge port of the sulfur-containing active carbon cache bin 9 is communicated with the feed port of the catalytic disproportionation tank 4 through a fourth material conveying device S4.

Example 6

Example 5 was repeated except that the discharge port of the sulfur-containing activated carbon buffer bin 9 was also in communication with the feed port of the sedimentation adsorption tank 3 via a fifth material conveying device S5.

Example 7

Example 6 is repeated except that the system further comprises a first solid-liquid separation device 10. The first solid-liquid separation device 10 is positioned between the catalytic disproportionation tank 4 and the colloid destabilization tank 5. The discharge port of the catalytic disproportionation tank 4 is connected with the feed port of the first solid-liquid separation device 10 through a sixth material conveying device S6. The water outlet of the first solid-liquid separation device 10 is communicated with the water inlet of the colloid destabilizing pond 5 through a sixth pipeline L6.

Example 8

Example 7 was repeated except that the discharge port of the first solid-liquid separation device 10 was also communicated with the feed port of the catalytic disproportionation tank 4 through the seventh material conveying device S7.

Example 9

Example 8 is repeated except that the system further comprises a second solid-liquid separation device 11. The feed inlet of the second solid-liquid separation device 11 is communicated with the discharge outlet of the colloid destabilizing pond 5 through an eighth material conveying device S8. A ninth material conveying device S9 is connected to the discharge port of the second solid-liquid separation device 11, and a seventh pipeline L7 is connected to the discharge port of the second solid-liquid separation device 11.

Example 10

Example 9 is repeated except that the system further comprises a sulfur drying device 12. The feed inlet of the sulfur drying device 12 is communicated with the discharge outlet of the second solid-liquid separation device 11 through a ninth material conveying device S9. The air inlet of the sulfur drying device 12 is connected with a protective gas conveying pipeline 1201.

Example 11

Example 10 is repeated except that the system further comprises a wastewater aftertreatment system 13. The water inlet of the wastewater aftertreatment system 13 is communicated with the water outlet of the second solid-liquid separation device 11 through a seventh pipeline L7.

Example 12

Example 11 is repeated except that the system further includes a sulfur storage bin 14. The sulfur storage bin 14 is communicated with a discharge port of the sulfur drying device 12 through a tenth material conveying device S10.

Example 13

Taking 5.0m of cyanide-containing SRG wastewater ³ The content of thiosulfate ions in the wastewater is detected to be 911mg/L, and the content of the activated carbon is detected to be 82mg/L.

Firstly separating out active carbon powder in the cyanide-containing SRG washing wastewater, and then taking 2.0m ³ And adding sulfuric acid into the cyanide-containing SRG washing wastewater to adjust the pH value to be less than 3. Then adding the activated carbon powder into the acidified cyanide-containing SRG wastewater at normal temperature and normal pressure for sedimentation and adsorption for 2 hours. And (3) carrying out solid-liquid separation after the adsorption is finished to obtain a solid I and a filtrate I, and drying the obtained solid I at 80 ℃ for 1h to obtain the sulfur-containing activated carbon I.

Example 14

Taking 5.0m of cyanide-containing SRG wastewater ³ The thiosulfate ion content in the wastewater is detected to be 1209mg/L, and the active carbon content is detected to be 71mg/L.

Firstly separating out active carbon powder in the cyanide-containing SRG washing wastewater, and then taking 2.5m ³ And adding sulfuric acid into the cyanide-containing SRG washing wastewater to adjust the pH value to be less than 2. Then adding the activated carbon powder into the acidified cyanide-containing SRG wastewater at normal temperature and normal pressure for sedimentation and adsorption for 2 hours. And (3) carrying out solid-liquid separation after the adsorption is finished to obtain a solid II and a filtrate II, and drying the obtained solid II at 70 ℃ for 2 hours to obtain the sulfur-containing activated carbon II.

Example 15

Example 13 was repeated except that 1.0m was taken again ³ And adding sulfuric acid into the cyanide-containing SRG washing wastewater to adjust the pH value to be less than 2. And then adding the sulfur-containing activated carbon I into the acidified cyanide-containing SRG wastewater at normal temperature and normal pressure for sedimentation and adsorption for 1h. And (3) carrying out solid-liquid separation after the adsorption is finished to obtain a solid III and a filtrate III, and drying the obtained solid III at 70 ℃ for 2 hours to obtain the sulfur-containing activated carbon III.

Example 16

Example 13 was repeated except that filtrate I and the remaining 3.0m were combined ³ The cyanide-containing SRG washing wastewater is uniformly mixed, and the concentration of bisulphite ions in the mixed washing wastewater is detected to be 64.67g/L. Then adding sulfur-containing active carbon I, and heating to 55 ℃ for disproportionation reaction; continuous monitoringAnd (3) filtering the pH value of the reaction system when the pH value of the reaction system is lower than 2, separating sulfur-containing active carbon and obtaining filtrate. The reaction was continued by heating the filtrate to 90 c until a sulfur precipitate was formed and a relatively clear supernatant was obtained. The sulphur precipitate was then separated and dried at 80℃for 2h under nitrogen protection to give 39.01kg elemental sulphur. The content of bisulfide ions in the wastewater after catalytic desulfurization is detected to be 0.56g/L.

Example 17

Example 14 was repeated except that filtrate II and the remaining 2.5m were combined ³ The cyanide-containing SRG washing wastewater is uniformly mixed, and the concentration of bisulphite ions in the mixed washing wastewater is detected to be 60.94g/L. Then adding sulfur-containing active carbon I, and heating to 55 ℃ for disproportionation reaction; and continuously monitoring the pH value of the reaction system, and filtering after the pH value of the reaction system is lower than 2, separating sulfur-containing activated carbon and obtaining filtrate. The reaction was continued by heating the filtrate to 90 c until a sulfur precipitate was formed and a relatively clear supernatant was obtained. The sulphur precipitate was then separated and dried at 80℃for 2h under nitrogen protection to give 36.88kg elemental sulphur. The content of bisulfide ions in the wastewater after catalytic desulfurization is detected to be 0.80g/L.

Example 18

Example 15 was repeated except that filtrate I, filtrate III and the remaining 2.0m ³ The cyanide-containing SRG washing wastewater is uniformly mixed, and the concentration of bisulphite ions in the mixed washing wastewater is detected to be 62.73g/L. Then adding sulfur-containing activated carbon III, and heating to 55 ℃ for disproportionation reaction; and continuously monitoring the pH value of the reaction system, and filtering after the pH value of the reaction system is lower than 2, separating sulfur-containing activated carbon and obtaining filtrate. The reaction was continued by heating the filtrate to 90 c until a sulfur precipitate was formed and a relatively clear supernatant was obtained. The sulphur precipitate was then separated and dried at 80℃for 2h under nitrogen protection to give 37.25kg elemental sulphur. The content of bisulfide ions in the wastewater after catalytic desulfurization is detected to be 0.42g/L.

Claims

1. The method for catalyzing and desalting the SRG washing wastewater is characterized by comprising the following steps of: the method comprises the following steps:

1) Separating out active carbon powder from the SRG washing wastewater, taking part of the SRG washing wastewater, adding acid to acidify, and then mixing the active carbon powder with the acidified part of the SRG washing wastewater to perform sedimentation adsorption; finally, solid-liquid separation is carried out to obtain sulfur-containing activated carbon and desulfurization wastewater; the amount of the partial SRG washing wastewater is such that the numerical ratio of the molar amount (mol) of thiosulfate in the partial SRG washing wastewater to the weight (g) of the activated carbon is 0.05-0.5:1;

2) Uniformly mixing desulfurization wastewater and residual SRG washing wastewater, and then adding sulfur-containing activated carbon to perform catalytic disproportionation reaction; the temperature of the disproportionation reaction is 40-55 ℃;

3) Continuously monitoring the pH value of the reaction system in the step 2) until the pH value changes to a pH set value; then carrying out solid-liquid separation to obtain filtrate;

2. The method according to claim 1, characterized in that: in step 1), the SRG washing wastewater is cyanide-containing SRG washing wastewater;

the acid is one or more of hydrochloric acid, sulfuric acid, nitric acid, nitrous acid and phosphoric acid.

3. The method according to claim 2, characterized in that: in step 1), the partial SRG washing wastewater is used in an amount such that the numerical ratio of the molar amount (mol) of thiosulfate in the partial SRG washing wastewater to the weight (g) of the activated carbon is 0.1-0.3:1; the acid is sulfuric acid.

4. A method according to claim 3, characterized in that: in step 1), the partial SRG wash wastewater is used in an amount such that the numerical ratio of the molar amount (mol) of thiosulfate in the partial SRG wash wastewater to the weight (g) of the activated carbon is 0.15-0.25:1.

5. The method according to any one of claims 2-4, wherein: in the step 2), the disproportionation reaction time is 0.3-10h; and/or

In step 3), the pH set point is < 3;

in step 4), the reaction temperature of the heating reaction is 50-120 ℃.

6. The method according to claim 5, wherein: in the step 2), the disproportionation reaction time is 0.5-8h; and/or

In step 3), the pH set point is < 2.5;

in step 4), the reaction temperature of the heating reaction is 60-110 ℃.

7. The method according to claim 6, wherein: in the step 2), the disproportionation reaction time is 0.8-5h; and/or

In step 3), the pH set point is < 2;

in step 4), the reaction temperature of the heating reaction is 70-100 ℃.

8. The method according to claim 5, wherein: the step 1) is specifically as follows: separating out active carbon powder in the SRG washing wastewater for standby, then taking part of the SRG washing wastewater, and adding acid into the part of the SRG washing wastewater to adjust the pH value to be less than 3; then adding activated carbon powder into the acidified SRG wastewater for sedimentation and adsorption for 0.3-5h; and (3) carrying out solid-liquid separation after the adsorption is finished to obtain solid and filtrate, and drying the obtained solid to obtain the sulfur-containing activated carbon.

9. The method according to claim 8, wherein: adding acid into the wastewater to adjust the pH value to be less than 2; the sedimentation and adsorption time is 0.5-3h.

10. The method according to claim 8 or 9, characterized in that: the sulfur-containing activated carbon is the activated carbon subjected to multiple sedimentation and adsorption; the SRG wash waste water used for each settling adsorption is derived from the original SRG wash waste water.

11. The method according to claim 10, wherein: the times of sedimentation adsorption of the sulfur-containing activated carbon are 2-10 times.

12. The method according to claim 11, wherein: the times of sedimentation adsorption of the sulfur-containing activated carbon are 3-5 times.

13. The method according to any one of claims 6-9, 11-12, characterized in that: the step 2) is specifically as follows: firstly, uniformly mixing the filtrate obtained after the solid-liquid separation in the step 1) with the rest SRG washing wastewater; then adding sulfur-containing active carbon, heating to perform disproportionation reaction for 0.3-10h, and performing step 3) after obtaining a disproportionation reaction system;

the step 3) is specifically as follows: continuously monitoring the pH value of the disproportionation reaction system in the step 2), and filtering when the pH value of the disproportionation reaction system is lower than 3, separating sulfur-containing active carbon and obtaining filtrate; returning the sulfur-containing activated carbon to the step 2) to be continuously used as a catalyst, and carrying out the step 4) on filtrate;

The step 4) is specifically as follows: continuously heating the filtrate obtained in the step 3) to 50-120 ℃ for reaction until sulfur precipitation is generated and a clear supernatant is obtained; and separating out sulfur precipitate, drying to obtain elemental sulfur, and discharging supernatant after the sulfur precipitate is separated out after being treated by a wastewater aftertreatment system.

14. The method according to claim 13, wherein: in step 2): adding sulfur-containing active carbon, heating to perform disproportionation reaction for 0.5-8h;

in step 3): filtering when the pH value of the disproportionation reaction system is lower than 2;

in step 4): and (3) continuously heating the filtrate obtained in the step (3) to 70-100 ℃ to react.

15. A system for catalytic desalination of SRG wash wastewater for use in the method of any of claims 1-14, characterized by: the system comprises a wastewater conveying device (1), a carbon-liquid separation tank (2), a sedimentation adsorption tank (3), a catalytic disproportionation tank (4) and a colloid destabilization tank (5); the wastewater conveying device (1) is communicated with a feed inlet of the carbon-liquid separation tank (2); the carbon-liquid separation tank (2), the sedimentation adsorption tank (3), the catalytic disproportionation tank (4) and the colloid destabilization tank (5) are sequentially connected in series.

16. The system according to claim 15, wherein: the system also comprises an acidification treatment tank (6), wherein the acidification treatment tank (6) is positioned between the carbon-liquid separation tank (2) and the sedimentation adsorption tank (3); the water outlet of the carbon-liquid separation tank (2) is communicated with the water inlet of the acidification treatment tank (6) through a first pipeline (L1); the water outlet of the acidification treatment tank (6) is communicated with the water inlet of the sedimentation adsorption tank (3) through a second pipeline (L2); an acid liquid conveying pipeline (601) is connected to an acid inlet of the acidification treatment tank (6); and/or

The system also comprises an active carbon cache bin (7); the active carbon cache bin (7) is positioned between the carbon-liquid separation tank (2) and the sedimentation adsorption tank (3); the discharge port of the carbon-liquid separation tank (2) is communicated with the feed port of the active carbon cache bin (7) through a first material conveying device (S1); the discharge port of the active carbon cache bin (7) is communicated with the feed port of the sedimentation adsorption tank (3) through a second material conveying device (S2).

17. The system according to claim 15 or 16, characterized in that: the system further comprises a mixing tank (8); the liquid mixing pool (8) is positioned between the sedimentation adsorption pool (3) and the catalytic disproportionation pool (4); the water outlet of the sedimentation adsorption tank (3) is communicated with the water inlet of the liquid mixing tank (8) through a third pipeline (L3); the water outlet of the carbon-liquid separation tank (2) is also communicated with the water inlet of the liquid mixing tank (8) through a fourth pipeline (L4); the water outlet of the liquid mixing tank (8) is communicated with the water inlet of the catalytic disproportionation tank (4) through a fifth pipeline (L5); and/or

The system also comprises a sulfur-containing active carbon buffer bin (9); the sulfur-containing active carbon cache bin (9) is positioned between the sedimentation adsorption tank (3) and the catalytic disproportionation tank (4); the discharge port of the sedimentation adsorption tank (3) is communicated with the feed port of the sulfur-containing active carbon cache bin (9) through a third material conveying device (S3); the discharge port of the sulfur-containing active carbon cache bin (9) is communicated with the feed port of the catalytic disproportionation tank (4) through a fourth material conveying device (S4).

18. The system according to claim 17, wherein: the discharge port of the sulfur-containing active carbon cache bin (9) is also communicated with the feed port of the sedimentation adsorption tank (3) through a fifth material conveying device (S5).

19. The system according to any one of claims 15-16, 18, wherein: the system further comprises a first solid-liquid separation device (10); the first solid-liquid separation device (10) is positioned between the catalytic disproportionation tank (4) and the colloid destabilization tank (5); the discharge port of the catalytic disproportionation tank (4) is connected with the feed port of the first solid-liquid separation device (10) through a sixth material conveying device (S6); the water outlet of the first solid-liquid separation device (10) is communicated with the water inlet of the colloid destabilizing pond (5) through a sixth pipeline (L6).

20. The system according to claim 19, wherein: the discharge port of the first solid-liquid separation device (10) is also communicated with the feed port of the catalytic disproportionation tank (4) through a seventh material conveying device (S7).

21. The system according to claim 20, wherein: the system also comprises a second solid-liquid separation device (11); the feed inlet of the second solid-liquid separation device (11) is communicated with the discharge outlet of the colloid destabilizing pond (5) through an eighth material conveying device (S8); a ninth material conveying device (S9) is connected to the discharge port of the second solid-liquid separation device (11), and a seventh pipeline (L7) is connected to the discharge port of the second solid-liquid separation device (11).

22. The system according to claim 19, wherein: the system also comprises a sulfur drying device (12); the feed inlet of the sulfur drying device (12) is communicated with the discharge outlet of the second solid-liquid separation device (11) through a ninth material conveying device (S9); and a protective gas conveying pipeline (1201) is connected to the air inlet of the sulfur drying device (12).

23. The system according to claim 22, wherein: the system also comprises a wastewater post-treatment system (13); the water inlet of the wastewater aftertreatment system (13) is communicated with the water outlet of the second solid-liquid separation device (11) through a seventh pipeline (L7).

24. The system according to claim 23, wherein: the system also comprises a sulfur storage bin (14); the sulfur storage bin (14) is communicated with a discharge port of the sulfur drying device (12) through a tenth material conveying device (S10).