CN114053840B - Internal circulation cleaning treatment method and system for cyanide-containing SRG gas - Google Patents

Internal circulation cleaning treatment method and system for cyanide-containing SRG gas Download PDF

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CN114053840B
CN114053840B CN202010779027.0A CN202010779027A CN114053840B CN 114053840 B CN114053840 B CN 114053840B CN 202010779027 A CN202010779027 A CN 202010779027A CN 114053840 B CN114053840 B CN 114053840B
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杨本涛
李佳
魏进超
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Zhongye Changtian International Engineering Co Ltd
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Abstract

An internal circulation cleaning and treating method for cyanide-containing SRG gas, which comprises the following steps: 1) The cyanide-containing SRG gas sequentially passes through a first-stage washing tower, a second-stage washing tower and a third-stage washing tower, and the washed gas is discharged from the top of the third-stage washing tower; 2) The gas discharged from the top of the three-stage washing tower enters an acid making system for acid making to obtain concentrated sulfuric acid; 3) The process water sequentially passes through a third-stage washing tower and a second-stage washing tower and then enters a first-stage washing tower; conveying concentrated sulfuric acid to a first-stage washing tower, and mixing the concentrated sulfuric acid with a solution in the first-stage washing tower to obtain an acidic washing solution; 4) The acidic washing solution washes and purifies the cyanogen-containing SRG gas, the wastewater at the lower part of the washing tower at the first stage after washing and purification is discharged to a primary sedimentation tank, and the wastewater at the upper part of the primary sedimentation tank enters SO 2 A desorption tower; 5) SO (SO) 2 Desorption tower for removing SO in wastewater 2 And discharging the acidic washing wastewater. According to the invention, through acid supplementing washing, sulfur dioxide can be prevented from being dissolved into acid washing wastewater, and the acid production yield is improved.

Description

Internal circulation cleaning treatment method and system for cyanide-containing SRG gas
Technical Field
The invention relates to a method for treating SRG gas, in particular to an internal circulation cleaning treatment method and system for cyanogen-containing SRG gas, belonging to the field of resource environmental protection.
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, acidic wash 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 of the acid washing wastewater generated by the cyanide-free SRG gas washing is 2-5 g/L, and the concentration of the hydrogen sulfite of the acid washing wastewater generated by the cyanide-containing SRG gas washing is 240-300 g/L.
The acidic washing wastewater with the high-concentration hydrogen sulfite has great 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 crystallized and separated out in the alkaline adding process, so that the system is blocked and paralyzed.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide an internal circulation cleaning and treating method and system for cyanogen-containing SRG gas. According to the method, part of concentrated sulfuric acid prepared in the acid preparation process is added into the first-stage washing tower, the washing solution of the first-stage washing tower is controlled to be acidic, so that physical dissolution of sulfur dioxide is effectively avoided, the recovery rate of sulfur dioxide is improved, and therefore the salt content of acidic washing wastewater is greatly reduced, and the sulfuric acid yield is greatly improved.
According to a first embodiment of the present invention, there is provided a method for the internal recycle cleaning management of a cyanide-containing SRG gas.
An internal circulation cleaning treatment method of cyanide-containing SRG gas, which comprises the following steps:
1) The SRG gas containing cyanogen enters a first-stage washing tower from the lower part, sequentially passes through the first-stage washing tower, a second-stage washing tower and a third-stage washing tower, and is respectively in countercurrent contact with washing solution in each tower, and the washed gas is discharged from the top of the third-stage washing tower.
2) And (3) introducing the gas discharged from the top of the three-stage washing tower into an acid making system for acid making to obtain concentrated sulfuric acid.
3) The process water enters a three-stage washing tower from the bottom, sequentially passes through the three-stage washing tower and the second-stage washing tower, and then enters the first-stage washing tower. And (3) conveying the concentrated sulfuric acid prepared in the step (2) to a first-stage washing tower, and mixing the concentrated sulfuric acid with the solution in the first-stage washing tower to obtain an acidic washing solution.
4) The acidic washing solution washes and purifies the cyanogen-containing SRG gas entering the primary washing tower, the wastewater at the lower part of the primary washing tower after washing and purification is discharged to a primary sedimentation tank, and the wastewater at the upper part of the primary sedimentation tank enters SO 2 And (3) a desorption tower.
5)SO 2 Desorption tower for removing SO physically dissolved in wastewater 2 And discharging the acidic washing wastewater.
In the present invention, the method further comprises: 6) The concentrated sulfuric acid obtained in step 2) was used for the sale.
Preferably, in step 1), the SRG gas is passed through a primary scrubber prior to being combined with SO 2 And merging sulfur-containing gas generated by the desorption tower, and then entering a secondary washing tower for washing and purifying.
Preferably, in step 4), a part of the wastewater in the upper part of the primary settling tank is fed (overflowed) to SO 2 The other part of the desorption tower is led into (overflowed to) the first-stage washing tower. Preferably, the wastewater in the lower portion of the primary settling tank enters a sludge storage tank.
In the present invention, the wastewater in the lower part (or bottom) of the primary settling tank can be passed to a sludge storage tank for further treatment. In the wastewater at the upper part of the primary sedimentation tank, the wastewater enters SO 2 The ratio of the waste water amount of the desorption tower to the waste water amount (volume) of the waste water introduced into the first-stage washing tower is 1:5-10.
Preferably, in the step 4), the wastewater at the upper part of the washing and purifying post-stage washing tower is recycled in the tower, and the wastewater at the lower part of the first-stage washing tower enters the primary settling tank.
Preferably, in the step 3), a part of the process water entering the three-stage washing tower is recycled in the three-stage washing tower, and the other part enters the second-stage washing tower. One part of the process water entering the second-stage washing tower from the third-stage washing tower is recycled in the second-stage washing tower, and the other part enters the first-stage washing tower.
In the invention, the first-stage washing tower, the second-stage washing tower and the third-stage washing tower aim at removing impurities in SRG gas by adopting wet washing, and the gas and the solution in the washing tower are in reverse contact, namely the gas flows from bottom to top and the solution flows from top to bottom. Wherein, the volume ratio of the solution amount used for the circulation in the three-stage washing tower to the solution amount introduced into the two-stage washing tower is 5-12:1. The ratio of the solution amount circularly used in the second-stage washing tower to the solution amount introduced into the first-stage washing tower is 5-12:1.
In the present invention, the pH of the acidic washing solution obtained in step 3) is 0 to 3, preferably 0.5 to 2.5, more preferably 1 to 2.
Preferably, in step 3), the amount of concentrated sulfuric acid fed to the primary scrubber is 1Nm per pass 3 0.02-0.2 kg of concentrated sulfuric acid, preferably 1Nm per pass 3 The SRG gas of (2) is added with 0.03-0.15 kg of concentrated sulfuric acid, more preferably 1Nm per ventilation 3 0.04-0.1 kg of concentrated sulfuric acid is added into the SRG gas.
That is, in the present invention, only a part (as needed) of the concentrated sulfuric acid produced in step 2) is fed to the primary scrubber, while the remaining part of the concentrated sulfuric acid is still available for sale.
In step 3) of the present invention, the pH of the liquid entering the three-stage scrubber is 5 to 7, preferably 5.5 to 6.5.
Preferably, in step 3), the pH of the liquid entering the secondary scrubber is between 3 and 5, preferably between 3.5 and 4.5.
Preferably, in step 3), the liquid entering the primary scrubber has a pH of 2 to 4, preferably 2.5 to 3.5.
In step 1) of the present invention, the temperature of the SRG gas entering the primary scrubber is from 250 to 480 ℃, preferably from 300 to 450 ℃, more preferably from 380 to 430 ℃.
Preferably, in step 1), the temperature of the gas entering the secondary scrubber is 50 to 150 ℃, preferably 70 to 100 ℃.
Preferably, in step 1), the gas temperature entering the three-stage scrubber is from 10 to 80 ℃, preferably from 30 to 60 ℃.
Preferably, in step 1), the temperature of the gas discharged from the three-stage scrubber is from 10 to 60 ℃, preferably from 20 to 40 ℃.
In step 3) of the present invention, the temperature of the liquid entering the three-stage scrubber is 10 to 60 ℃, preferably 20 to 40 ℃.
Preferably, in step 3), the temperature of the liquid entering the secondary scrubber is between 10 and 80 ℃, preferably between 30 and 60 ℃.
Preferably, in step 3), the temperature of the liquid entering the primary scrubber is from 30 to 100 ℃, preferably from 50 to 80 ℃.
Preferably, in step 4), the temperature of the liquid discharged from the primary scrubber is 50 to 120 ℃, preferably 70 to 90 ℃.
In step 4) of the present invention, the concentration of suspended matter in the wastewater in the upper part of the primary scrubber is 400 to 2100mg/L, preferably 500 to 2000mg/L.
In step 4) of the present invention, the concentration of suspended matter in the wastewater in the lower part of the primary scrubber is 600 to 2500mg/L, preferably 800 to 2300mg/L.
In step 4) of the present invention, the concentration of suspended matter in the wastewater at the upper part of the preliminary tank is 0 to 100mg/L, preferably 1 to 80mg/L, more preferably 2 to 50mg/L.
The primary settling tank removes suspended matters through the sedimentation effect of the gravity of the suspended matters.
Preferably, in step 5), SO is removed from the wastewater 2 When going to SO 2 Air is introduced into the desorption tower.
According to a second embodiment of the present invention, an internal recycle cleaning abatement system for a cyanide-containing SRG gas is provided.
A system for cleaning a process for remediation of a cyanide-containing SRG gas using the method described above, the system comprising: primary washing tower, secondary washing tower, tertiary washing tower, acid making system, primary settling tank and SO 2 And (3) a desorption tower. The SRG gas conveying pipeline is connected to the gas inlet of the first-stage washing tower, the gas outlet of the first-stage washing tower is connected to the gas inlet of the second-stage washing tower through a first pipeline, the gas outlet of the second-stage washing tower is connected to the gas inlet of the third-stage washing tower through a second pipeline, and the gas outlet of the third-stage washing tower is connected to the acid making system through a third pipeline.
The process water conveying pipeline is connected to the bottom liquid inlet of the three-stage washing tower, the liquid outlet of the three-stage washing tower is connected to the lower liquid inlet of the second-stage washing tower through a fourth pipeline, the liquid outlet of the second-stage washing tower is connected to the lower liquid inlet of the first-stage washing tower through a fifth pipeline, the lower liquid outlet of the first-stage washing tower is connected to the primary settling tank through a sixth pipeline, and the upper liquid outlet of the primary settling tank is connected to SO through a seventh pipeline 2 A liquid inlet of the desorption column. The liquid outlet of the acid making system is connected to the bottom liquid inlet of the first-stage washing tower through a concentrated sulfuric acid conveying pipeline.
In the present invention, the bottom liquid outlet of the primary settling tank may be connected to a sludge storage tank by a pipe, i.e., the wastewater at the bottom (or lower portion) of the primary settling tank may be discharged to the sludge storage tank for further treatment.
Preferably, an eighth conduit is split off the seventh conduit, the eighth conduit being connected to the upper liquid inlet of the primary scrubber. Preferably, a ninth conduit leading from the upper liquid outlet of the primary scrubber is connected to the upper liquid inlet of the primary scrubber.
Preferably, a tenth conduit is split off from the fifth conduit, the tenth conduit being connected to the upper liquid inlet of the secondary scrubber. An eleventh pipeline is separated from the fourth pipeline, and the eleventh pipeline is connected to the upper liquid inlet of the three-stage washing tower.
In the invention, the gas inlet of the first-stage washing tower, the second-stage washing tower or the third-stage washing tower is arranged at the lower part of the corresponding device, and the gas outlet is arranged at the top of the corresponding device. The bottom liquid inlet is typically located at the bottom of the device. While the upper liquid inlet and the lower liquid inlet are a relative concept, generally the upper liquid inlet is arranged in the upper part of the device and the lower liquid inlet is arranged in the lower part of the device, the upper liquid inlet being located above the lower liquid inlet. The upper liquid outlet and the lower liquid outlet are also a relative concept, and generally the upper liquid outlet is located above the lower liquid outlet.
Preferably SO 2 The gas outlet of the desorption column is connected to the first conduit via a twelfth conduit. Preferably, the air delivery conduit is connected to the SO 2 A gas inlet of the desorption column.
In the prior art, after the SRG gas is washed and purified by process water, sulfur dioxide gas with higher purity is obtained and is used for preparing acid by two-rotation and two-absorption, and the waste water generated after washing is finally discharged from a system after passing through a stripping tower, so that acid washing waste water is formed. Generally, the acidic materials in SRG gases are greater than the basic materials, and thus, acidic wash wastewater tends to be acidic. However, when cyanide and its derivatives are present in the front-end flue gas, the cyanide and its derivatives may enter the SRG gas and eventually dissolve in the wash wastewater, and as the cyanic acid hydrolyzes to form ammonia nitrogen, the dissolution of cyanide and its derivatives may increase the alkalinity of the wash wastewater, rendering the wash wastewater neutral. When the washing wastewater is neutral, a large amount of SO in SRG gas can be caused 2 The acid gas dissolves, causing a sharp increase in sulfite in the wastewater. The washing wastewater with high concentration of sulfite has great treatment difficulty.
In consideration of the condition that cyanide and derivatives thereof exist in front-end flue gas, the invention aims at improving the washing and recycling process of SRG gas, and concentrated sulfuric acid prepared in an acid preparation process is added into a first-stage washing tower, so that the washing solution of the first-stage washing tower shows stronger acidity (the pH value is 0-3, preferably 0.5-2.5, more preferably 1-2). The invention introduces the concentrated sulfuric acid prepared by the acid preparation system into the first-stage washing tower, and has the following advantages:
(1) The cyanide and the derivative thereof are hydrolyzed into ammonium ions, so that the washing liquid is weak acid or neutral. According to SO 3 2- The ion fraction curve of (2) shows that SO when the solution is weakly acidic or neutral 2 Can be dissolved and become bisulphite. Thus, the solution for washing the SRG is mainly prepared by ammonium bisulfate (NH) 4 HSO 3 ) There is one cyanide and its derivatives available according to reactions (1) and (2) that can react with one sulfur dioxide. By reasonable control of the process of the invention, the pH of the solution is adjusted by means of externally added sulfuric acid, so that the solution mainly exists as ammonium sulfate, which is available according to reaction (3), and two cyanides and derivatives thereof are required to react with one sulfate radical.
Cyanide and derivative hydrolysis: HOCN+H 2 O→NH 3 +CO 2 (1)
The reaction when the solution is weakly acidic or neutral: NH (NH) 3 +SO 2 +H 2 O→NH 4 HSO 3 (2)
After the acid is regulated by the solution: 2NH 4 HSO 3 +H 2 SO 4 →(NH 4 ) 2 SO 4 +2H 2 O+2SO 2 (3)
According to the reaction process, the salt content of the acid washing wastewater can be greatly reduced, and the sulfuric acid yield can be greatly improved.
Before the process of the invention is adopted, the wastewater amount is 4m according to the detection result 3 And/h, wherein the chloride ion content is 35g/L, the total concentration of sulfate radicals and hydrogen sulfite radicals is 238g/L, and the concentration of the hydrogen sulfite radicals is 200g/L.
As a result of the fact that,
Figure BDA0002619534160000051
Reduced salt mass concentration = ammonium bisulfide mass concentration-ammonium sulphate mass concentration,
thus, the first and second substrates are bonded together,
Figure BDA0002619534160000052
thus, the percentage reduction in salt mass concentration is the ratio of the reduced salt mass concentration after the process of the invention to the salt mass concentration before the process of the invention:
percentage reduction in salt concentration = reduced salt mass concentration +.f (original ammonium sulfate mass concentration + ammonium bisulfide mass concentration + ammonium chloride mass concentration);
the preparation method comprises the following steps:
Figure BDA0002619534160000053
the reaction may not take place completely due to the fact that the reaction is not complete. Therefore, according to the actual improvement result, the salt mass concentration in the acid washing wastewater can be reduced by about 21% after the process is adopted.
In addition, from reaction (3), it was found that the modified process produced 1mol of sulfur dioxide corresponding to 1mol of the reaction system, but consumed 0.5mol of sulfuric acid at the same time, i.e., increased 0.5mol of sulfuric acid. According to the detection result, the acid yield before process modification is 29.5t/d. The reaction process for preparing sulfuric acid from sulfur dioxide comprises the following steps:
sulfur dioxide conversion process: 2SO 2 +O 2 →2SO 3 (4)
Absorption process: SO (SO) 3 +H 2 O→H 2 SO 4 (5)
Thus, 98% sulfuric acid yield = increased sulfuric acid amount per cubic water x water amount x 24 h/sulfuric acid mass fraction;
Namely: increase 98% sulfuric acid yield = 200/81 x 98 x 4 x 24/1000/98% = 23.7t/d;
reaction consumption 98% sulfuric acid amount=200/81×98×4×24/1000/98%/2=11.85 t/d;
total increase sulfuric acid amount= (increase 98% sulfuric acid yield-reaction consumption 98% sulfuric acid amount) ×actual reaction efficiency, i.e.:
total increase in sulfuric acid = 11.85 x 21/23.32 = 10.67t/d;
after transformation, the acid yield reaches 40.17t/d.
Thus, with the process of the present invention, the sulfuric acid yield is increased by 36.17%.
(2) The washing solution of the first-stage washing tower is controlled to be acidic after the concentrated sulfuric acid is added, so that the physical dissolution of sulfur dioxide can be effectively avoided, the recovery rate of the sulfur dioxide is improved, and the gas property of the acid-making wastewater is improved.
(3) The self-produced concentrated sulfuric acid in the method is directly added into a system, so that the internal recycling of sulfur resources is realized, additional substances are avoided, the operation is simple, and the improvement is convenient.
(4) The purpose of controlling the concentrated sulfuric acid to be added into the primary scrubbing tower instead of the secondary scrubbing tower or the tertiary scrubbing tower is to control the scrubbing solution of the secondary scrubbing tower or the tertiary scrubbing tower to be weak acid or neutral. This is because the sulfur-rich gas contains cyanide and its derivatives, sulfur dioxide, and hydrogen fluoride, hydrogen chloride, and the like. The acidity is unfavorable for the removal of hydrogen fluoride and hydrogen chloride, so that the washing solution of the secondary washing tower or the tertiary washing tower is controlled to be weak acid or neutral so as to remove the hydrogen fluoride, the hydrogen chloride and the like in the SRG gas.
In addition, in the prior art, the SRG gas is washed by the washing solution in the first-stage washing tower, the wastewater at the lower part of the first-stage washing tower after washing and purifying is introduced into the conical settling tank, and the wastewater at the upper part of the conical settling tank overflows to the supernatant storage tank. According to practical research, the carbon powder in the washing wastewater is finer, and when a conical sedimentation tank and a supernatant liquid storage tank are adopted, the carbon powder is not settled enough due to larger disturbance in water in the operation process, so that the solution circulated to the primary washing tower also contains more carbon powder. After several times of circulation, the carbon powder amount in the solution can be increased sharply, and the discharge of the acid-making wastewater is increased to avoid the blockage of the washing nozzle. In the present invention, a primary settling tank is used instead of a conical settling tank and a supernatant storage tank. Because the primary settling tank adopts a mode of entering from the middle and exiting from the two sides, the hydraulic disturbance is less, and the sedimentation of carbon powder is facilitated, so that the discharge amount of the acid-making wastewater is less.
Before the process of the invention is adopted, the suspended matters in the wastewater are higher, so that the chloride ion concentration in the water is generally 50000mg/L. After improvement, the suspended matters are low and are no longer used as control indexes. The control index can be adjusted to detect the concentration of chloride ions in the primary precipitation tank to be 70000mg/L. I.e. the wastewater can be concentrated by 1.4 times, and the water quantity can be reduced by 28.6 percent. According to the actual improvement results, the amount of wastewater can be reduced by about 25%.
The invention provides an internal circulation cleaning and treating method and system for cyanide-containing SRG gas, wherein the technical process and the technical principle are briefly described as follows:
(1) three-stage washing: according to the nature of the SRG gas components, three stages of scrubbing are adopted, wherein the first stage is used for removing dust, cyanide and derivatives thereof and a small amount of fluorine and chlorine in the SRG gas, and simultaneously reducing the temperature of flue gas. The second stage is mainly used for removing fluorine and chlorine, deeply removing impurities and further reducing the temperature of SRG gas. The third stage is a deep removing section of the pollutant, and the pollutant which cannot be removed due to the fluctuation of the previous two stages is removed.
(2) Acid washing: the cyanide and the derivative thereof are hydrolyzed into ammonium ions, so that the washing liquid is weak acid or neutral. And introducing the prepared concentrated sulfuric acid into a first-stage washing tower, regulating the washing solution of the first-stage washing tower to be acidic, avoiding the reaction of cyanide and derivatives thereof with sulfur dioxide, and inhibiting the formation of ammonium bisulfide. Thereby realizing the great reduction of the salt content of the acid washing wastewater and the great improvement of the sulfuric acid yield. According to the actual improvement result, the salt content in the acid washing wastewater can be reduced by 20% and the sulfuric acid yield can be increased by 46.7% by adopting acid supplementing washing.
(3) Primary wash split cycle: the wastewater containing suspended carbon powder at the upper part of the circulating primary washing tower is aimed at controlling the content of a certain carbon powder in the washing solution. It has been shown from research that SRG gas contains sulfur vapors and thus forms colloidal sulfur during the scrubbing process. Therefore, the aim of controlling the washing solution to contain a certain amount of carbon powder is to adsorb the colloidal sulfur in the washing solution by using the carbon powder, so as to prevent the colloidal sulfur from sticking to equipment and blocking.
(4) And (3) separating carbon powder: the principle that the carbon powder is easy to settle by self gravity is utilized to realize the removal of the carbon powder. In the invention, the primary sedimentation tank is adopted to replace the conical sedimentation tank and the supernatant liquid storage tank, and because the primary sedimentation tank adopts a mode of entering from the middle and exiting from the two sides, water inlet and water outlet and mud discharge are independent, disturbance is basically avoided, and secondary suspension of settled fine carbon powder can be avoided.
⑤SO 2 Blowing off: the acidic washing wastewater contains a certain amount of sulfurous acid in SO 2 The desorption tower is filled with air, SO that the decomposition of sulfurous acid can be accelerated, and SO can be realized 2 Blowing out to improve the sulfuric acid yield.
The invention provides an internal circulation cleaning and treating method and system for cyanogen-containing SRG gas, which can be used for treating desorption gas of an adsorbent by an adsorption method, wherein the cyanogen-containing SRG gas is only one of the cyanogen-containing SRG gas. Wherein the adsorbent comprises a solid or liquid, e.g., the adsorbent is one or more of activated carbon, molecular sieves, MOFs, ionic liquids, organic amines.
Compared with the prior art, the invention has the following beneficial technical effects:
1. the invention washes and SO by acid supplementing 2 The stripping mode can avoid sulfur dioxide from being dissolved into acid washing wastewater, thereby improving acid yield.
2. The salt content of the acid washing wastewater discharged by the method is greatly reduced, the treatment cost of the acid washing wastewater is correspondingly reduced, and the subsequent treatment cost can be reduced.
3. The invention adopts moderate carbon powder circulation and acid washing modes, can lead the colloid sulfur to enter the carbon powder for removal, avoids blocking equipment, prevents the simple substance sulfur from forming thiosulfate and entering the wastewater, and reduces the treatment difficulty of the acid washing wastewater.
4. The invention can realize the cleaning treatment of the SRG gas by reasonably designing the SRG gas washing process and utilizing the SRG product and reasonably designing the washing and purifying process on the basis of not adding other substances.
Drawings
FIG. 1 is a process flow diagram of an internal recycle cleaning abatement process for a cyanide-containing SRG gas of the present invention;
FIG. 2 is a schematic diagram of an internal recycle cleaning abatement system for cyanide-containing SRG gas according to the present invention;
FIG. 3 is SO 3 2- Ion fraction graph of (2).
Reference numerals: 1: a first-stage washing tower; 2: a second-stage scrubber; 3: three-stage washing towers; 4: an acid making system; 5: a primary sedimentation tank; 6: SO (SO) 2 A desorption tower;
la: an SRG gas delivery conduit; lb: a process water delivery pipe; lc: concentrated sulfuric acid conveying pipeline; ld: an air delivery conduit;
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; l8: an eighth conduit; l9: a ninth conduit; l10: a tenth pipe; l11: an eleventh conduit; l12: a twelfth duct.
Detailed Description
According to a first embodiment of the present invention, there is provided a method for the internal recycle cleaning management of a cyanide-containing SRG gas.
An internal circulation cleaning treatment method of cyanide-containing SRG gas, which comprises the following steps:
1) The SRG gas containing cyanogen enters a first-stage washing tower 1 from the lower part, sequentially passes through the first-stage washing tower 1, a second-stage washing tower 2 and a third-stage washing tower 3, and is respectively in countercurrent contact with washing solutions in the towers, and the washed gas is discharged from the top of the third-stage washing tower 3.
2) And (3) introducing the gas discharged from the top of the three-stage washing tower 3 into an acid making system 4 for acid making to obtain concentrated sulfuric acid.
3) The process water enters a three-stage washing tower 3 from the bottom, sequentially passes through the three-stage washing tower 3 and a second-stage washing tower 2, and then enters a first-stage washing tower 1. And (3) conveying the concentrated sulfuric acid prepared in the step (2) to a first-stage washing tower 1, and mixing the concentrated sulfuric acid with the solution in the first-stage washing tower 1 to obtain an acidic washing solution.
4) The acidic washing solution washes and purifies the cyanogen-containing SRG gas entering the primary washing tower 1, the wastewater at the lower part of the primary washing tower 1 after washing and purification is discharged to the primary sedimentation tank 5, and the wastewater at the upper part of the primary sedimentation tank 5 enters SO 2 And a desorption column 6.
5)SO 2 Desorption tower 6 removes SO physically dissolved in wastewater 2 And discharging the acidic washing wastewater.
In the present invention, the method further comprises: 6) The concentrated sulfuric acid obtained in step 2) was used for the sale.
Preferably, in step 1), the SRG gas is passed through the primary scrubber 1 prior to being combined with SO 2 The sulfur-containing gas generated by the desorption tower 6 is converged and then enters the secondary washing tower 2 for washing and purifying.
Preferably, in step 4), a part of the wastewater in the upper part of the preliminary sedimentation tank 5 is introduced into SO 2 The other part of the desorption tower 6 is led into the first-stage washing tower 1. Preferably, the wastewater in the lower part of the primary settling tank 5 enters a sludge storage tank.
Preferably, in the step 4), the wastewater at the upper part of the washing and purifying post-stage washing tower 1 is recycled in the tower, and the wastewater at the lower part of the first-stage washing tower 1 enters the primary settling tank 5.
Preferably, in the step 3), a part of the process water entering the tertiary washing tower 3 is recycled in the tertiary washing tower 3, and the other part enters the secondary washing tower 2. One part of the process water entering the second-stage washing tower 2 from the third-stage washing tower 3 is recycled in the second-stage washing tower 2, and the other part enters the first-stage washing tower 1.
In the present invention, the pH of the acidic washing solution obtained in step 3) is 0 to 3, preferably 0.5 to 2.5, more preferably 1 to 2.
Preferably, in step 3), the amount of concentrated sulfuric acid fed to the primary scrubber 1 is 1Nm per pass 3 0.02-0.2 kg of concentrated sulfuric acid, preferably 1Nm per pass 3 The SRG gas of (2) is added with 0.03-0.15 kg of concentrated sulfuric acid, more preferably 1Nm per ventilation 3 0.04-0.1 kg of concentrated sulfuric acid is added into the SRG gas.
In step 3) of the present invention, the pH of the liquid entering the three-stage scrubber 3 is 5 to 7, preferably 5.5 to 6.5.
Preferably, in step 3), the pH of the liquid entering the secondary scrubber 2 is between 3 and 5, preferably between 3.5 and 4.5.
Preferably, in step 3), the pH of the liquid entering the primary scrubber 1 is between 2 and 4, preferably between 2.5 and 3.5.
In step 1) of the present invention, the temperature of the SRG gas entering the primary scrubber 1 is 250 to 480 ℃, preferably 300 to 450 ℃, more preferably 380 to 430 ℃.
Preferably, in step 1), the temperature of the gas entering the secondary scrubber 2 is 50 to 150 ℃, preferably 70 to 100 ℃.
Preferably, in step 1), the temperature of the gas entering the three-stage scrubber 3 is between 10 and 80 ℃, preferably between 30 and 60 ℃.
Preferably, in step 1), the temperature of the gas discharged from the three-stage scrubber 3 is 10 to 60 ℃, preferably 20 to 40 ℃.
In step 3) of the present invention, the temperature of the liquid entering the three-stage scrubber 3 is 10 to 60 ℃, preferably 20 to 40 ℃.
Preferably, in step 3), the temperature of the liquid entering the secondary scrubber 2 is between 10 and 80 ℃, preferably between 30 and 60 ℃.
Preferably, in step 3), the temperature of the liquid entering the primary scrubber 1 is between 30 and 100 ℃, preferably between 50 and 80 ℃.
Preferably, in step 4), the temperature of the liquid discharged from the primary scrubber 1 is 50 to 120 ℃, preferably 70 to 90 ℃.
In step 4) of the present invention, the concentration of suspended matter in the wastewater in the upper part of the primary scrubber 1 is 400 to 2100mg/L, preferably 500 to 2000mg/L.
In step 4) of the present invention, the concentration of suspended matter in the wastewater in the lower part of the primary scrubber 1 is 600 to 2500mg/L, preferably 800 to 2300mg/L.
In step 4) of the present invention, the concentration of suspended matter in the wastewater in the upper portion of the preliminary tank 5 is 0 to 100mg/L, preferably 1 to 80mg/L, more preferably 2 to 50mg/L.
Preferably, in step 5), SO is removed from the wastewater 2 When going to SO 2 The desorption tower 6 is filled with air.
According to a second embodiment of the present invention, an internal recycle cleaning abatement system for a cyanide-containing SRG gas is provided.
A system for cleaning a process for remediation of a cyanide-containing SRG gas using the method described above, the system comprising: a first-stage washing tower 1, a second-stage washing tower 2, a third-stage washing tower 3, an acid making system 4, a primary settling tank 5 and SO 2 And a desorption column 6.SRG gas delivery line L a Is connected to the gas inlet of the primary scrubber 1, the gas outlet of the primary scrubber 1 is connected to the gas inlet of the secondary scrubber 2 via a first pipe L1, the gas outlet of the secondary scrubber 2 is connected to the gas inlet of the tertiary scrubber 3 via a second pipe L2, and the gas outlet of the tertiary scrubber 3 is connected to the acid making system 4 via a third pipe L3.
Process water conveying pipeline L b Is connected to the bottom liquid inlet of the three-stage scrubber 3, the liquid outlet of the three-stage scrubber 3 is connected to the lower liquid inlet of the second-stage scrubber 2 via a fourth pipe L4, the liquid outlet of the second-stage scrubber 2 is connected to the lower liquid inlet of the first-stage scrubber 1 via a fifth pipe L5, the lower liquid outlet of the first-stage scrubber 1 is connected to the primary settling tank 5 via a sixth pipe L6, and the upper liquid outlet of the primary settling tank 5 is connected to SO via a seventh pipe L7 2 The liquid inlet of the desorption column 6. The liquid outlet of the acid making system 4 is connected to the bottom liquid inlet of the primary scrubber 1 via a concentrated sulfuric acid delivery pipe Lc.
Preferably, the seventh pipe L7 is branched off from an eighth pipe L8, and the eighth pipe L8 is connected to the upper liquid inlet of the primary scrubber 1. Preferably, a ninth pipe L9 leading from the upper liquid outlet of the primary scrubber 1 is connected to the upper liquid inlet of the primary scrubber 1.
Preferably, a tenth pipe L10 is branched from the fifth pipe L5, and the tenth pipe L10 is connected to the upper liquid inlet of the secondary scrubber 2. An eleventh line L11 is branched from the fourth line L4, and the eleventh line L11 is connected to the upper liquid inlet of the three-stage scrubber 3.
Preferably SO 2 The gas outlet of the desorption column 6 is connected to the first conduit L1 via a twelfth conduit L12. Preferably, the air delivery duct Ld is connected to SO 2 The gas inlet of the desorption column 6.
Example 1
As shown in FIG. 2, an internal recycle cleaning and abatement system for cyanide-containing SRG gasA system, the system comprising: a first-stage washing tower 1, a second-stage washing tower 2, a third-stage washing tower 3, an acid making system 4, a primary settling tank 5 and SO 2 And a desorption column 6.SRG gas delivery line L a Is connected to the gas inlet of the primary scrubber 1, the gas outlet of the primary scrubber 1 is connected to the gas inlet of the secondary scrubber 2 via a first pipe L1, the gas outlet of the secondary scrubber 2 is connected to the gas inlet of the tertiary scrubber 3 via a second pipe L2, and the gas outlet of the tertiary scrubber 3 is connected to the acid making system 4 via a third pipe L3.
Process water conveying pipeline L b Is connected to the bottom liquid inlet of the three-stage scrubber 3, the liquid outlet of the three-stage scrubber 3 is connected to the lower liquid inlet of the second-stage scrubber 2 via a fourth pipe L4, the liquid outlet of the second-stage scrubber 2 is connected to the lower liquid inlet of the first-stage scrubber 1 via a fifth pipe L5, the lower liquid outlet of the first-stage scrubber 1 is connected to the primary settling tank 5 via a sixth pipe L6, and the upper liquid outlet of the primary settling tank 5 is connected to SO via a seventh pipe L7 2 The liquid inlet of the desorption column 6. The liquid outlet of the acid making system 4 is connected to the bottom liquid inlet of the primary scrubber 1 via a concentrated sulfuric acid delivery pipe Lc.
Example 2
Example 1 was repeated except that an eighth pipe L8 was branched from the seventh pipe L7, and the eighth pipe L8 was connected to the upper liquid inlet of the primary scrubber 1.
Example 3
Example 2 was repeated except that a ninth pipe L9, which was led out from the upper liquid outlet of the primary scrubber 1, was connected to the upper liquid inlet of the primary scrubber 1. A tenth pipe L10 is branched from the fifth pipe L5, and the tenth pipe L10 is connected to the upper liquid inlet of the secondary scrubber 2. An eleventh line L11 is branched from the fourth line L4, and the eleventh line L11 is connected to the upper liquid inlet of the three-stage scrubber 3.
Example 4
Example 3 was repeated except that SO 2 The gas outlet of the desorption column 6 is connected to the first conduit L1 via a twelfth conduit L12.
Example 5
Example 4 was repeated except that the air delivery line Ld was connected to SO 2 The gas inlet of the desorption column 6.
Example 6
As shown in fig. 1, a method for internal recycle cleaning and remediation of a cyanide-containing SRG gas using the system of example 5, the method comprising the steps of:
1) The SRG gas containing cyanogen enters a first-stage washing tower 1 from the lower part, sequentially passes through the first-stage washing tower 1, a second-stage washing tower 2 and a third-stage washing tower 3, and is respectively in countercurrent contact with washing solutions in the towers, and the washed gas is discharged from the top of the third-stage washing tower 3.
Wherein the temperature of the SRG gas entering the primary scrubber 1 is 400 ℃. The temperature of the gas entering the secondary scrubber 2 was 80 ℃. The temperature of the gas entering the three-stage scrubber 3 was 50 ℃. The temperature of the gas discharged from the three-stage scrubber 3 was 30 ℃.
2) And (3) introducing the gas discharged from the top of the three-stage washing tower 3 into an acid making system 4 for acid making to obtain concentrated sulfuric acid.
3) The process water enters a three-stage washing tower 3 from the bottom, sequentially passes through the three-stage washing tower 3 and a second-stage washing tower 2, and then enters a first-stage washing tower 1. And (3) conveying the concentrated sulfuric acid prepared in the step (2) to a first-stage washing tower 1, and mixing the concentrated sulfuric acid with the solution in the first-stage washing tower 1 to obtain an acidic washing solution.
Wherein the pH value of the liquid entering the three-stage washing tower 3 is 6.5, and the temperature is 30 ℃. The liquid entering the secondary scrubber 2 had a pH of 4 and a temperature of 40 ℃. The liquid entering the primary scrubber 1 had a pH of 3 and a temperature of 60 ℃. The amount of concentrated sulfuric acid fed to the primary scrubber 1 was 1Nm per pass 3 0.08kg of concentrated sulfuric acid was added to the SRG gas. The pH of the resulting acidic wash solution was 2.
4) The acidic washing solution washes and purifies the cyanogen-containing SRG gas entering the primary washing tower 1, the wastewater at the lower part of the primary washing tower 1 after washing and purification is discharged to the primary sedimentation tank 5, and the wastewater at the upper part of the primary sedimentation tank 5 enters SO 2 And a desorption column 6.
Wherein the temperature of the liquid discharged from the primary scrubber 1 was 80 ℃. The concentration of suspended matters in the wastewater at the upper part of the primary sedimentation tank 5 is 5mg/L.
5)SO 2 Desorption tower 6 removes SO physically dissolved in wastewater 2 And discharging the acidic washing wastewater.
Example 7
Example 6 was repeated except that the method further comprises: 6) The concentrated sulfuric acid obtained in step 2) was used for the sale.
In the case of example 8,
example 7 was repeated except that in step 1), the gas discharged from the primary scrubber 1 was reacted with SO 2 And the sulfur-containing gas generated by the desorption tower 6 is converged and then enters the secondary washing tower 2 for washing and purifying.
Example 9
Example 8 was repeated except that in step 4), the wastewater at the upper part of the primary scrubber 1 after washing and purification was recycled in the column, and the wastewater at the lower part of the primary scrubber 1 was introduced into the primary settling tank 5. The concentration of suspended matters in the wastewater at the upper part of the primary washing tower 1 is 1000mg/L. The concentration of suspended matters in the wastewater at the lower part of the primary washing tower 1 was 1500mg/L. Part of the wastewater at the upper part of the primary sedimentation tank 5 overflows to SO 2 The other part of the desorption tower 6 overflows to the first-stage washing tower 1. The wastewater at the lower part of the primary sedimentation tank 5 is led into a sludge storage tank for further treatment.
In the step 3), one part of the process water entering the three-stage washing tower 3 is recycled in the three-stage washing tower 3, and the other part enters the second-stage washing tower 2. One part of the process water entering the second-stage washing tower 2 from the third-stage washing tower 3 is recycled in the second-stage washing tower 2, and the other part enters the first-stage washing tower 1.
Example 10
Example 9 was repeated, except that in step 5), SO was removed from the wastewater 2 When going to SO 2 The desorption tower 6 is filled with air.
Experiments were carried out according to the method for internal circulation cleaning and treating of cyanide-containing SRG gas provided in this example. The amount of wastewater, the concentration of suspended substances in wastewater, (sulfuric acid, sulfurous acid) salt, the concentration of chloride ions, and the yield of sulfuric acid before the process of this example were measured, and then the amount of wastewater, the concentration of suspended substances in wastewater, (sulfuric acid, sulfurous acid) salt, the concentration of chloride ions, and the yield of sulfuric acid after the process of this example was measured.
Detection index Before the process of the embodiment After the process of the embodiment is adopted
Waste water amount, m 3 /h 4 3
Suspension concentration, g/L 3.2 0.1
(sulfuric acid, sulfurous acid) salt concentration, g/L 238 290
Concentration of chloride ion, g/L 35 46.6
Sulfuric acid yield, t/d 29.5 40.17

Claims (36)

1. An internal circulation cleaning treatment method of cyanide-containing SRG gas, which comprises the following steps:
1) introducing the SRG gas containing cyanogen into a first-stage washing tower (1) from the lower part, sequentially passing through the first-stage washing tower (1), a second-stage washing tower (2) and a third-stage washing tower (3), enabling the SRG gas to be respectively in countercurrent contact with washing solutions in the towers, and discharging the washed gas from the top of the third-stage washing tower (3);
2) The gas discharged from the top of the three-stage washing tower (3) enters an acid making system (4) for acid making to obtain concentrated sulfuric acid;
3) The process water enters a three-stage washing tower (3) from the bottom, sequentially passes through the three-stage washing tower (3) and a second-stage washing tower (2), and then enters a first-stage washing tower (1); conveying the concentrated sulfuric acid prepared in the step 2) to a first-stage washing tower (1), and mixing the concentrated sulfuric acid with the solution in the first-stage washing tower (1) to obtain an acidic washing solution;
4) The acidic washing solution washes and purifies the cyanogen-containing SRG gas entering the first-stage washing tower (1), the wastewater at the lower part of the first-stage washing tower (1) after washing and purification is discharged to a primary sedimentation tank (5), and the wastewater at the upper part of the primary sedimentation tank (5) enters SO 2 A desorption column (6);
5)SO 2 the desorption tower (6) removes the SO physically dissolved in the wastewater 2 And discharging the acidic washing wastewater.
2. The method according to claim 1, characterized in that: the method further comprises the steps of: 6) The concentrated sulfuric acid obtained in step 2) was used for the sale.
3. The method according to claim 1, characterized in that: in step 1), SRG gas is firstly reacted with SO after passing through a first-stage washing tower (1) 2 The sulfur-containing gas generated by the desorption tower (6) is converged and then enters the secondary washing tower (2) for washing and purifying; and/or
In the step 4), part of wastewater at the upper part of the primary sedimentation tank (5) enters SO 2 And the other part of the desorption tower (6) is led into the first-stage washing tower (1).
4. A method according to claim 3, characterized in that: the wastewater at the lower part of the primary sedimentation tank (5) enters a sludge storage tank.
5. The method according to any one of claims 1-4, wherein: in the step 4), the wastewater at the upper part of the washing and purifying post-stage washing tower (1) is recycled in the tower, and the wastewater at the lower part of the first-stage washing tower (1) enters a primary sedimentation tank (5); and/or
In the step 3), one part of the process water entering the three-stage washing tower (3) is recycled in the three-stage washing tower (3), and the other part enters the second-stage washing tower (2); one part of the process water entering the second-stage washing tower (2) from the third-stage washing tower (3) is recycled in the second-stage washing tower (2), and the other part enters the first-stage washing tower (1).
6. The method according to any one of claims 1-4, wherein: the pH value of the acidic washing solution obtained in the step 3) is 0 to 3.
7. The method according to claim 5, wherein: the pH value of the acidic washing solution obtained in the step 3) is 0 to 3.
8. The method according to claim 6, wherein: the pH value of the acidic washing solution obtained in the step 3) is 0.5 to 2.5.
9. The method according to claim 7, wherein: the pH value of the acidic washing solution obtained in the step 3) is 0.5 to 2.5.
10. The method according to claim 8 or 9, characterized in that: the pH value of the acidic washing solution obtained in the step 3) is 1 to 2.
11. The method according to claim 6, wherein: in step 3), the amount of concentrated sulfuric acid fed to the primary scrubber (1) was 1Nm per pass 3 0.02-0.2 kg of concentrated sulfuric acid is added into the SRG gas.
12. The method according to claim 7, wherein: in step 3), the amount of concentrated sulfuric acid fed to the primary scrubber (1) was 1Nm per pass 3 Adding concentrated sulfuric acid into the SRG gas of 0.02-0.2kg。
13. The method according to claim 11 or 12, characterized in that: in step 3), the amount of concentrated sulfuric acid fed to the primary scrubber (1) was 1Nm per pass 3 0.03-0.15 kg of concentrated sulfuric acid is added into the SRG gas.
14. The method according to claim 13, wherein: in step 3), the amount of concentrated sulfuric acid fed to the primary scrubber (1) was 1Nm per pass 3 0.04-0.1 kg of concentrated sulfuric acid is added into the SRG gas.
15. The method according to any one of claims 1-4, 7-9, 11-12, 14, characterized in that: in the step 3), the pH value of the liquid entering the three-stage washing tower (3) is 5-7; and/or
In the step 3), the pH value of the liquid entering the secondary washing tower (2) is 3-5; and/or
In the step 3), the pH value of the liquid entering the primary washing tower (1) is 2-4.
16. The method according to claim 5, wherein: in the step 3), the pH value of the liquid entering the three-stage washing tower (3) is 5-7; and/or
In the step 3), the pH value of the liquid entering the secondary washing tower (2) is 3-5; and/or
In the step 3), the pH value of the liquid entering the primary washing tower (1) is 2-4.
17. The method according to claim 15, wherein: in the step 3), the pH value of the liquid entering the three-stage washing tower (3) is 5.5-6.5; and/or
In the step 3), the pH value of the liquid entering the secondary washing tower (2) is 3.5-4.5; and/or
In the step 3), the pH value of the liquid entering the primary washing tower (1) is 2.5-3.5.
18. The method according to claim 16, wherein: in the step 3), the pH value of the liquid entering the three-stage washing tower (3) is 5.5-6.5; and/or
In the step 3), the pH value of the liquid entering the secondary washing tower (2) is 3.5-4.5; and/or
In the step 3), the pH value of the liquid entering the primary washing tower (1) is 2.5-3.5.
19. The method of any one of claims 1-4, 7-9, 11-12, 14, 16-18, wherein: in the step 1), the temperature of SRG gas entering the first-stage washing tower (1) is 250-480 ℃; and/or
In the step 1), the temperature of the gas entering the secondary washing tower (2) is 50-150 ℃; and/or
In the step 1), the temperature of the gas entering the three-stage washing tower (3) is 10-80 ℃; and/or
In step 1), the temperature of the gas discharged from the three-stage scrubber (3) is 10 to 60 ℃.
20. The method according to claim 5, wherein: in the step 1), the temperature of SRG gas entering the first-stage washing tower (1) is 250-480 ℃; and/or
In the step 1), the temperature of the gas entering the secondary washing tower (2) is 50-150 ℃; and/or
In the step 1), the temperature of the gas entering the three-stage washing tower (3) is 10-80 ℃; and/or
In step 1), the temperature of the gas discharged from the three-stage scrubber (3) is 10 to 60 ℃.
21. The method according to claim 19, wherein: in the step 1), the temperature of SRG gas entering the first-stage washing tower (1) is 300-450 ℃; and/or
In the step 1), the temperature of the gas entering the secondary washing tower (2) is 70-100 ℃; and/or
In the step 1), the temperature of the gas entering the three-stage washing tower (3) is 30-60 ℃; and/or
In step 1), the temperature of the gas discharged from the three-stage scrubber (3) is 20 to 40 ℃.
22. The method according to claim 20, wherein: in the step 1), the temperature of SRG gas entering the first-stage washing tower (1) is 300-450 ℃; and/or
In the step 1), the temperature of the gas entering the secondary washing tower (2) is 70-100 ℃; and/or
In the step 1), the temperature of the gas entering the three-stage washing tower (3) is 30-60 ℃; and/or
In step 1), the temperature of the gas discharged from the three-stage scrubber (3) is 20 to 40 ℃.
23. The method of any one of claims 1-4, 7-9, 11-12, 14, 16-18, 20-22, wherein: in the step 3), the temperature of the liquid entering the three-stage washing tower (3) is 10-60 ℃; and/or
In the step 3), the temperature of the liquid entering the secondary washing tower (2) is 10-80 ℃; and/or
In the step 3), the temperature of the liquid entering the primary washing tower (1) is 30-100 ℃; and/or
In step 4), the temperature of the liquid discharged from the primary scrubber (1) is 50 to 120 ℃.
24. The method according to claim 5, wherein: in the step 3), the temperature of the liquid entering the three-stage washing tower (3) is 10-60 ℃; and/or
In the step 3), the temperature of the liquid entering the secondary washing tower (2) is 10-80 ℃; and/or
In the step 3), the temperature of the liquid entering the primary washing tower (1) is 30-100 ℃; and/or
In step 4), the temperature of the liquid discharged from the primary scrubber (1) is 50 to 120 ℃.
25. The method according to claim 23, wherein: in the step 3), the temperature of the liquid entering the three-stage washing tower (3) is 20-40 ℃; and/or
In the step 3), the temperature of the liquid entering the secondary washing tower (2) is 30-60 ℃; and/or
In the step 3), the temperature of the liquid entering the primary washing tower (1) is 50-80 ℃; and/or
In step 4), the temperature of the liquid discharged from the primary scrubber (1) is 70 to 90 ℃.
26. The method according to claim 24, wherein: in the step 3), the temperature of the liquid entering the three-stage washing tower (3) is 20-40 ℃; and/or
In the step 3), the temperature of the liquid entering the secondary washing tower (2) is 30-60 ℃; and/or
In the step 3), the temperature of the liquid entering the primary washing tower (1) is 50-80 ℃; and/or
In step 4), the temperature of the liquid discharged from the primary scrubber (1) is 70 to 90 ℃.
27. A method according to claim 3 or 4, characterized in that: in the step 4), the concentration of suspended matters in the wastewater at the upper part of the primary washing tower (1) is 400-2100 mg/L; and/or
In the step 4), the concentration of suspended matters in the wastewater at the lower part of the primary washing tower (1) is 600-2500 mg/L.
28. The method according to claim 27, wherein: in the step 4), the concentration of suspended matters in the wastewater at the upper part of the primary washing tower (1) is 500-2000 mg/L; and/or
In the step 4), the concentration of suspended matters in the wastewater at the lower part of the primary washing tower (1) is 800-2300 mg/L.
29. The method of any one of claims 1-4, 7-9, 11-12, 14, 16-18, 20-22, 24-26, 28, wherein: in the step 4), the concentration of suspended matters in the wastewater at the upper part of the primary sedimentation tank (5) is 0-100 mg/L; and/or
In step 5), SO is removed from the wastewater 2 When going to SO 2 Air is introduced into the desorption tower (6).
30. The method according to claim 5, wherein: in the step 4), the concentration of suspended matters in the wastewater at the upper part of the primary sedimentation tank (5) is 0-100 mg/L; and/or
In step 5), SO is removed from the wastewater 2 When going to SO 2 Air is introduced into the desorption tower (6).
31. The method according to claim 29, wherein: in the step 4), the concentration of suspended matters in the wastewater at the upper part of the primary sedimentation tank (5) is 1-80 mg/L.
32. The method according to claim 30, wherein: in the step 4), the concentration of suspended matters in the wastewater at the upper part of the primary sedimentation tank (5) is 1-80 mg/L.
33. The method according to claim 31 or 32, characterized in that: in the step 4), the concentration of suspended matters in the wastewater at the upper part of the primary sedimentation tank (5) is 2-50 mg/L.
34. A system for cleaning a process for treating a cyanide-containing SRG gas using the method of any of claims 1-33, the system comprising: a first-stage washing tower (1), a second-stage washing tower (2), a third-stage washing tower (3), an acid making system (4), a primary settling tank (5) and SO 2 A desorption column (6); SRG gas transfer pipe (L) a ) The device comprises a gas inlet connected to a first-stage washing tower (1), wherein a gas outlet of the first-stage washing tower (1) is connected to a gas inlet of a second-stage washing tower (2) through a first pipeline (L1), a gas outlet of the second-stage washing tower (2) is connected to a gas inlet of a third-stage washing tower (3) through a second pipeline (L2), and a gas outlet of the third-stage washing tower (3) is connected to an acid production system (4) through a third pipeline (L3); and
Art water conveying pipe (L) b ) Is connected to the bottom liquid inlet of the three-stage washing tower (3), the liquid outlet of the three-stage washing tower (3) is connected to the lower liquid inlet of the second-stage washing tower (2) through a fourth pipeline (L4), the liquid outlet of the second-stage washing tower (2) is connected to the lower liquid inlet of the first-stage washing tower (1) through a fifth pipeline (L5), the lower liquid outlet of the first-stage washing tower (1) is connected to the primary sedimentation tank (5) through a sixth pipeline (L6), and the upper liquid outlet of the primary sedimentation tank (5) is connected to SO through a seventh pipeline (L7) 2 A liquid inlet of the desorption column (6); the liquid outlet of the acid making system (4) is connected to the bottom liquid inlet of the primary washing tower (1) through a concentrated sulfuric acid conveying pipeline (Lc).
35. The system according to claim 34, wherein: an eighth pipeline (L8) is separated from the seventh pipeline (L7), and the eighth pipeline (L8) is connected to an upper liquid inlet of the primary washing tower (1); and/or
A tenth pipeline (L10) is separated from the fifth pipeline (L5), and the tenth pipeline (L10) is connected to an upper liquid inlet of the secondary washing tower (2); an eleventh pipeline (L11) is separated from the fourth pipeline (L4), and the eleventh pipeline (L11) is connected to an upper liquid inlet of the three-stage washing tower (3); and/or
SO 2 The gas outlet of the desorption column (6) is connected to the first conduit (L1) via a twelfth conduit (L12).
36. The system according to claim 35, wherein: a ninth pipe (L9) leading from the upper liquid outlet of the primary scrubber (1) is connected to the upper liquid inlet of the primary scrubber (1); an air delivery conduit (Ld) is connected to the SO 2 A gas inlet of the desorption tower (6).
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