CN114053834B - External circulation cleaning treatment method and system for cyanogen-containing SRG gas - Google Patents

External circulation cleaning treatment method and system for cyanogen-containing SRG gas Download PDF

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CN114053834B
CN114053834B CN202010779000.1A CN202010779000A CN114053834B CN 114053834 B CN114053834 B CN 114053834B CN 202010779000 A CN202010779000 A CN 202010779000A CN 114053834 B CN114053834 B CN 114053834B
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washing tower
wastewater
sulfuric acid
stage washing
gas
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CN114053834A (en
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李佳
朱刚
杨本涛
彭建宏
罗同维
肖海娟
肖祁春
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Hunan Zhongye Changtian Energy Conservation And Environmental Protection Technology Co ltd
Zhongye Changtian International Engineering Co Ltd
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Hunan Zhongye Changtian Energy Conservation And Environmental Protection Technology Co ltd
Zhongye Changtian International Engineering Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1406—Multiple stage absorption
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D47/00—Separating dispersed particles from gases, air or vapours by liquid as separating agent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D47/00—Separating dispersed particles from gases, air or vapours by liquid as separating agent
    • B01D47/06—Spray cleaning
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1456—Removing acid components
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/69—Sulfur trioxide; Sulfuric acid
    • C01B17/74—Preparation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/20—Treatment of water, waste water, or sewage by degassing, i.e. liberation of dissolved gases
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/20—Halogens or halogen compounds
    • B01D2257/202—Single element halogens
    • B01D2257/2025—Chlorine
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/20—Halogens or halogen compounds
    • B01D2257/202—Single element halogens
    • B01D2257/2027—Fluorine
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/40—Nitrogen compounds
    • B01D2257/408—Cyanides, e.g. hydrogen cyanide (HCH)
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F2001/007—Processes including a sedimentation step
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/18—Nature of the water, waste water, sewage or sludge to be treated from the purification of gaseous effluents

Abstract

An external circulation cleaning treatment method of cyanide-containing SRG gas, comprising 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 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 three-stage washing tower, a second-stage washing tower and a first-stage washing tower to wash and purify the SRG gas containing cyanide, the wastewater in the washing and purifying first-stage washing tower 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; SO (SO) 2 Desorption tower for removing SO in wastewater 2 Then discharging the wastewater to a wastewater collection tank; 4) Conveying the process water and the concentrated sulfuric acid into a concentrated sulfuric acid diluter for mixing to obtain dilute sulfuric acid; and (3) introducing dilute sulfuric acid into a wastewater collecting tank, reacting the dilute sulfuric acid with wastewater, and discharging acid washing wastewater. According to the invention, through acidification and stripping, waste gas is circulated into the system, so that secondary pollution is prevented, and the acid production yield is improved.

Description

External circulation cleaning treatment method and system for cyanogen-containing SRG gas
Technical Field
The invention relates to a method for treating SRG gas, in particular to an external 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 acid washing wastewater hydrogen sulfite generated by cyanide-free SRG gas washing The concentration is 2-5 g/L, and the concentration of the hydrogen sulfite of the acid washing wastewater generated by washing the cyanide-containing SRG gas 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 external circulation cleaning treatment method and system for cyanogen-containing SRG gas. The invention dilutes part of concentrated sulfuric acid prepared in the acid preparation process, regulates the washing wastewater to be acidic and then discharges the acidic washing wastewater, and utilizes a self system to treat waste gas, thereby preventing secondary pollution, and realizing the substantial reduction of the salt content of the acidic washing wastewater and the substantial improvement of the sulfuric acid yield.
According to a first embodiment of the present invention, there is provided an external circulation cleaning and remediation process for a cyanide-containing SRG gas.
An external 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, the process water sequentially passes through the three-stage washing tower, a second-stage washing tower and a first-stage washing tower to wash and purify the SRG gas containing cyanide, the wastewater in the washing and purifying first-stage washing tower 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. SO (SO) 2 Desorption tower for removing SO physically dissolved in wastewater 2 The wastewater is then discharged to a wastewater collection tank.
4) And (3) conveying the process water and the concentrated sulfuric acid prepared in the step (2) into a concentrated sulfuric acid diluter for mixing to obtain dilute sulfuric acid. And (3) introducing dilute sulfuric acid into a wastewater collecting tank, reacting the dilute sulfuric acid with wastewater, and discharging acid washing wastewater after the reaction.
In the present invention, the method comprises: 5) The concentrated sulfuric acid obtained in step 2) was used for the sale.
Preferably, in step 4), compressed air is introduced into the wastewater collection tank during the reaction of dilute sulfuric acid with wastewater.
Preferably, in step 3), the wastewater in the lower part of the primary settling tank is passed to a wastewater collection tank. Preferably, the wastewater at the lower part of the primary settling tank is also led to a sludge storage tank.
In the invention, one part of the wastewater at the lower part (or bottom) of the primary sedimentation tank is introduced into a wastewater collection tank, and the other part is introduced into a sludge storage tank for further treatment. The wastewater amount introduced into the wastewater collection tank is 1/20-1/30 of the total wastewater amount of the primary sedimentation tank.
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), the waste gas after the reaction of dilute sulfuric acid with the waste water is introduced into SO 2 And (3) a desorption tower.
Preferably, in step 3), SO is removed from the wastewater 2 When going to SO 2 Air is introduced into the desorption tower.
In step 3) of the present invention, a part of the wastewater in the upper part of the preliminary sedimentation tank enters (overflows to) SO 2 The other part of the desorption tower is led into (overflowed to) the first-stage washing tower.
In the invention, the wastewater at the upper part of the primary sedimentation tank 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 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 step 4) of the present invention, the pH of the acidic washing wastewater after the reaction of dilute sulfuric acid with the wastewater is 0 to 3, preferably 0.5 to 2.5, more preferably 1 to 2.
Preferably, in step 4), the amount of dilute sulfuric acid fed to the wastewater collection tank is such that the ratio of the molar amount of hydrogen ions in the dilute sulfuric acid to the molar amount of sulfite ions in the wastewater is from 1:0.1 to 1, preferably from 1:0.2 to 0.6, more preferably from 1:0.3 to 0.5.
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.
Preferably, the concentration of sulfuric acid in the dilute sulfuric acid is 30 to 80%, preferably 40 to 70%, more preferably 50 to 60%.
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.
Preferably, in step 3), the liquid discharged from the primary scrubber has a pH of 4 to 6, preferably 4.5 to 5.5.
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 3), the temperature of the liquid discharged from the primary scrubber is 50 to 120 ℃, preferably 70 to 90 ℃.
In the present invention, the concentration of suspended matter in the wastewater collection tank is 600 to 2500mg/L, preferably 800 to 2300mg/L.
In the invention, a part of wastewater at the bottom of the primary sedimentation tank is introduced into the wastewater collection tank to control the suspended matter content of the wastewater collection tank so as to realize the adsorption of colloidal sulfur.
In step 3) 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.
According to a second embodiment of the present invention, an external circulation 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 A desorption tower, a waste water collecting tank and a concentrated sulfuric acid diluter. The SRG gas conveying pipeline is connected to the gas inlet of the first-stage washing tower, and the gas of the first-stage washing towerThe outlet is connected to the gas inlet of the second-stage scrubber via a first conduit, the gas outlet of the second-stage scrubber is connected to the gas inlet of the third-stage scrubber via a second conduit, and the gas outlet of the third-stage scrubber is connected to the acid making system via a third conduit.
The first conveying pipeline of the process water 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 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. SO (SO) 2 The liquid outlet of the desorption column is connected to the wastewater collection tank via an eighth conduit. The liquid outlet of the acid making system is connected to the concentrated sulfuric acid diluter through a concentrated sulfuric acid conveying pipeline, and the process water second conveying pipeline is connected to the concentrated sulfuric acid diluter. The liquid outlet of the concentrated sulfuric acid diluter is connected via a ninth pipe to the liquid inlet of the wastewater collection tank.
Preferably, the compressed air delivery conduit is connected to a gas inlet of the wastewater collection tank.
Preferably, the bottom liquid outlet of the primary settling tank is connected to the liquid inlet of the wastewater collection tank via a tenth conduit. Preferably, an eleventh pipeline is branched from the tenth pipeline, and the eleventh pipeline is connected to the sludge storage tank.
Preferably, a twelfth pipe leading from the waste gas outlet of the waste water collecting tank is connected to the SO 2 A gas inlet of the desorption column. SO (SO) 2 The gas outlet of the desorption column is connected to the first conduit via a thirteenth conduit.
Preferably, the air delivery duct is connected to the twelfth duct.
Preferably, a fourteenth pipe is branched from the seventh pipe, and the fourteenth pipe is connected to the upper liquid inlet of the first-stage scrubber.
Preferably, a fifteenth pipe is branched from the fifth pipe, and the fifteenth pipe is connected to the upper liquid inlet of the secondary scrubber. A sixteenth pipeline is separated from the fourth pipeline and 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.
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 self-produced sulfuric acid is diluted, washing wastewater is regulated to be acidic and then discharged, and a self-system is utilized for waste gas treatment. By this improvement, there are 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, wash SThe RG solution is mainly composed of 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. Because of the low pH required for forming the bisulfate, the invention adds dilute sulfuric acid into the wastewater, and can decompose ammonium bisulfate into SO through reasonable control 2 The solution is mainly ammonium sulfate. According to reaction (3) two cyanides and derivatives thereof are required to react with one sulfate.
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 40g/L, the total concentration of sulfate radicals and hydrogen sulfite radicals is 238g/L, and the concentration of the hydrogen sulfite radicals is 160g/L.
Reduced salt mass concentration = ammonium bisulfide mass concentration-ammonium sulphate mass concentration,
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:
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 14.4% 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 32t/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 = 160/81 x 98 x 4 x 24/1000/98% = 18.96t/d;
reaction consumption 98% sulfuric acid amount=160/81×98×4×24/1000/98%/2=9.48 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 sulfuric acid = 9.48 x 14.4/17.95 = 7.61t/d;
after transformation, the acid yield reaches 39.61t/d.
Thus, with the process of the present invention, the sulfuric acid yield is increased by 23.78%.
(2) After the wastewater collection Chi Suanxing washing wastewater reacts with dilute sulfuric acid, ammonium bisulfate can be decomposed into SO 2 After compressed air is introducedThe reaction is exacerbated and a large amount of acid gas is evolved. The acid gas, if discharged at will, can lead to atmospheric pollution. Due to SO 2 The desorption tower adopts negative pressure air intake to introduce acid gas generated by the reaction into SO 2 The desorption tower further enters a secondary washing tower, so that the atmospheric pollution can be avoided and the recovery of sulfur resources can be realized.
(3) The invention directly adds the sulfuric acid self-produced in the two-rotation two-suction process into the system, realizes the internal recycling of sulfur resources, avoids additional substances, and has simple operation and convenient improvement.
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 water entering the wastewater collection tank can be reduced by about 25%.
The invention provides an external 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) 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.
(3) Acidifying and blowing off: the pH value of the wastewater solution generated by the primary washing tower is 4-6, and the wastewater solution contains a large amount of ammonium bisulfide. After adding dilute sulfuric acid to the solution, the bisulfate in the ammonium bisulfate is converted into sulfurous acid. The sulfurous acid is decomposed to release sulfur dioxide under the condition of acidity and air disturbance. One sulfate radical is used to replace two bisulfites, so that the salt concentration is reduced. The research shows that the acidification stripping is an endothermic reaction, and the risk of aeration does not exist. However, the concentration of the dilute sulfuric acid added is not too high, which can lead to corrosion of equipment, and the reaction is severe, so that local high temperature is generated. However, the concentration of the added dilute sulfuric acid is not too low, and the reaction speed is slow, the average acid consumption is increased, and a large amount of wastewater is generated. Therefore, the concentration of the dilute sulfuric acid is preferably selected to be medium to high (for example, the concentration of sulfuric acid in the dilute sulfuric acid is 30 to 80%, preferably 40 to 70%, more preferably 50 to 60%).
④SO 2 Blowing off and recycling: the acidic washing wastewater contains a certain amount of sulfurous acid in SO 2 Air is introduced into the desorption tower, so that the decomposition of sulfurous acid can be accelerated, and sulfur dioxide is blown out. In addition, sulfur dioxide blown off by acidification enters SO 2 And the negative pressure pipeline of the desorption tower prevents sulfur dioxide from escaping, and can recover sulfur resources and improve sulfuric acid yield.
(5) Colloid sulfur adsorption: studies have shown that SRG gas containing sulfur vapor is scrubbed into solution in a primary column and further reacts with bisulphite to form thiosulfate. Thiosulfate enters a wastewater collection tank along with wastewater and is decomposed under acidic conditions to generate colloidal sulfur. Based on the property of activated carbon for adsorbing the colloidal sulfur, the wastewater (namely the carbon powder part) at the bottom of the primary sedimentation tank is transferred into the wastewater collection tank, so that the deep removal of the colloidal sulfur is realized, and the blocking caused by the sticking of the colloidal sulfur to equipment is prevented.
The invention provides an external circulation cleaning treatment 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 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.
2. According to the invention, through acidification and stripping, waste gas is circulated into the system based on the characteristics of the system, so that secondary pollution is prevented, and acid yield is improved.
3. 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.
4. The invention adopts neutral washing to convert elemental sulfur into a dissolved state, avoids blocking washing equipment, combines waste carbon powder adsorption, controls the source of decomposed colloidal sulfur, and avoids blocking the equipment.
Drawings
FIG. 1 is a process flow diagram of an external circulation cleaning abatement process for cyanide-containing SRG gases of the present invention;
FIG. 2 is a schematic diagram of an external circulation cleaning and remediation 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; 7: a wastewater collection tank; 8: a concentrated sulfuric acid diluter; 9: a sludge storage tank;
la: an SRG gas delivery conduit; lb: a first process water delivery pipe; lc: concentrated sulfuric acid conveying pipeline; ld: a second conveying pipeline for process water; le: a compressed air delivery conduit; lf: 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; l13: a thirteenth conduit; l14: a fourteenth conduit; l15: a fifteenth conduit; l16: sixteenth pipe.
Detailed Description
According to a first embodiment of the present invention, there is provided an external circulation cleaning and remediation process for a cyanide-containing SRG gas.
An external 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, the process water sequentially passes through the three-stage washing tower 3, a second-stage washing tower 2 and a first-stage washing tower 1 to wash and purify the SRG gas containing cyanide, the wastewater in 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 And a desorption column 6.SO (SO) 2 Desorption tower 6 removes SO physically dissolved in wastewater 2 The wastewater is then discharged to a wastewater collection tank 7.
4) And (3) conveying the process water and the concentrated sulfuric acid prepared in the step (2) into a concentrated sulfuric acid diluter (8) for mixing to obtain dilute sulfuric acid. And (3) introducing dilute sulfuric acid into a wastewater collection tank 7, reacting the dilute sulfuric acid with wastewater, and discharging acid washing wastewater after the reaction.
In the present invention, the method comprises: 5) The concentrated sulfuric acid obtained in step 2) was used for the sale.
Preferably, in step 4), compressed air is introduced into the waste water collection tank 7 during the reaction of dilute sulfuric acid with the waste water.
Preferably, in step 3), the wastewater in the lower part of the preliminary sedimentation tank 5 is passed into a wastewater collection tank 7. Preferably, the wastewater in the lower part of the primary settling tank 5 is also led to a sludge storage tank 9.
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), the waste gas after the reaction of dilute sulfuric acid with the waste water is introduced into SO 2 And a desorption column 6.
Preferably, in step 3), SO is removed from the wastewater 2 When going to SO 2 The desorption tower 6 is filled with air.
In step 3) of the present invention, 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, 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 step 4) of the present invention, the pH of the acidic washing wastewater after the reaction of dilute sulfuric acid with the wastewater is 0 to 3, preferably 0.5 to 2.5, more preferably 1 to 2.
Preferably, in step 4), the amount of dilute sulfuric acid fed to the wastewater collection tank 7 is such that the ratio of the molar amount of hydrogen ions in the dilute sulfuric acid to the molar amount of sulfite ions in the wastewater is 1:0.1-1, preferably 1:0.2-0.6, more preferably 1:0.3-0.5.
Preferably, the concentration of sulfuric acid in the dilute sulfuric acid is 30 to 80%, preferably 40 to 70%, more preferably 50 to 60%.
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.
Preferably, in step 3), the pH of the liquid discharged from the primary scrubber 1 is from 4 to 6, preferably from 4.5 to 5.5.
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 3), the temperature of the liquid discharged from the primary scrubber 1 is 50 to 120 ℃, preferably 70 to 90 ℃.
In the present invention, the concentration of suspended matter in the wastewater collection tank 7 is 600 to 2500mg/L, preferably 800 to 2300mg/L.
In step 3) of the present invention, the concentration of suspended matter in the wastewater at the upper part of the preliminary tank 5 is 0 to 100mg/L, preferably 1 to 80mg/L, more preferably 2 to 50mg/L.
According to a second embodiment of the present invention, an external circulation 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 A desorption tower 6, a waste water collecting tank 7 and a concentrated sulfuric acid diluter 8.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.
First conveying pipeline L of process water 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 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. SO (SO) 2 The liquid outlet of the desorption column 6 is connected to a waste water collection tank 7 via an eighth conduit L8. The liquid outlet of the acid making system 4 is connected to a concentrated sulfuric acid diluter 8 via a concentrated sulfuric acid delivery pipe Lc, a process water second delivery pipe L d Is connected to a concentrated sulfuric acid diluter 8. The liquid outlet of the concentrated sulfuric acid diluter 8 is connected to the liquid inlet of the wastewater collection tank 7 via a ninth pipe L9.
Preferably, the compressed air delivery conduit Le is connected to the gas inlet of the wastewater collection tank 7.
Preferably, the bottom liquid outlet of the primary settling tank 5 is connected via a tenth conduit L10 to the liquid inlet of the wastewater collection tank 7. Preferably, an eleventh pipeline L11 is branched from the tenth pipeline L10, and the eleventh pipeline L11 is connected to the sludge storage tank 9.
PreferablyIs that a twelfth pipe L12 led from the exhaust gas outlet of the wastewater collection tank 7 is connected to SO 2 The gas inlet of the desorption column 6. SO (SO) 2 The gas outlet of the desorption column 6 is connected to the first conduit L1 via a thirteenth conduit L13.
Preferably, the air delivery duct Lf is connected to the twelfth duct L12.
Preferably, the seventh line L7 is branched off from a fourteenth line L14, and the fourteenth line L14 is connected to the upper liquid inlet of the first-stage scrubber 1.
Preferably, the fifth line L5 is branched off from a fifteenth line L15, and the fifteenth line L15 is connected to the upper liquid inlet of the secondary scrubber 2. The fourth line L4 is branched off from a sixteenth line L16, and the sixteenth line L16 is connected to the upper liquid inlet of the three-stage scrubber 3.
Example 1
As shown in fig. 2, an external circulation cleaning abatement system for a cyanide-containing SRG gas, 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 tower 6, a waste water collecting tank 7 and a concentrated sulfuric acid diluter 8.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.
First conveying pipeline L of process water 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 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. SO (SO) 2 The liquid outlet of the desorption column 6 is connected to a waste water collection tank 7 via an eighth conduit L8. The liquid outlet of the acid making system 4 is connected to the concentrated sulfuric acid delivery pipe LcSulfuric acid diluter 8, process water second conveying pipeline L d Is connected to a concentrated sulfuric acid diluter 8. The liquid outlet of the concentrated sulfuric acid diluter 8 is connected to the liquid inlet of the wastewater collection tank 7 via a ninth pipe L9.
Example 2
Example 1 was repeated except that the compressed air delivery pipe Le was connected to the gas inlet of the wastewater collection tank 7.
Example 3
Example 2 was repeated except that the bottom liquid outlet of the primary settling tank 5 was connected to the liquid inlet of the wastewater collection tank 7 via a tenth pipe L10. An eleventh pipe L11 is branched from the tenth pipe L10, and the eleventh pipe L11 is connected to the sludge tank 9.
Example 4
Example 3 was repeated except that the twelfth pipe L12 led from the exhaust gas outlet of the wastewater collection tank 7 was connected to SO 2 The gas inlet of the desorption column 6. SO (SO) 2 The gas outlet of the desorption column 6 is connected to the first conduit L1 via a thirteenth conduit L13. The air delivery duct Lf is connected to the twelfth duct L12.
Example 5
Example 4 was repeated except that a fourteenth pipe L14 was branched from the seventh pipe L7, and the fourteenth pipe L14 was connected to the upper liquid inlet of the primary scrubber 1. The fifth line L5 branches off from a fifteenth line L15, the fifteenth line L15 being connected to the upper liquid inlet of the secondary scrubber 2. The fourth line L4 is branched off from a sixteenth line L16, and the sixteenth line L16 is connected to the upper liquid inlet of the three-stage scrubber 3.
Example 6
As shown in fig. 1, an external circulation cleaning abatement process for cyanide-containing SRG gas, using the system of example 5, comprises 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 40 ℃. 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, the process water sequentially passes through the three-stage washing tower 3, a second-stage washing tower 2 and a first-stage washing tower 1 to wash and purify the SRG gas containing cyanide, the wastewater in 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 And a desorption column 6.SO (SO) 2 Desorption tower 6 removes SO physically dissolved in wastewater 2 The wastewater is then discharged to a wastewater collection tank 7.
Wherein the pH value of the liquid entering the three-stage washing tower 3 is 6, and the temperature is 30 ℃. The pH value of the liquid entering the secondary washing tower 2 is 3 and the temperature is 50 ℃. The pH of the liquid entering the primary scrubber 1 was 2.5 and the temperature was 60 ℃. The liquid discharged from the primary scrubber 1 had a pH of 5 and a temperature of 80 ℃. The concentration of suspended matters in the wastewater at the upper part of the primary sedimentation tank 5 was 3mg/L.
4) And (3) conveying the process water and the concentrated sulfuric acid prepared in the step (2) into a concentrated sulfuric acid diluter (8) for mixing to obtain dilute sulfuric acid. And (3) introducing dilute sulfuric acid into a wastewater collection tank 7, reacting the dilute sulfuric acid with wastewater, and discharging acid washing wastewater after the reaction.
Wherein the amount of the dilute sulfuric acid fed into the wastewater collection tank 7 is the ratio of the molar amount of hydrogen ions in the dilute sulfuric acid to the molar amount of sulfite ions in the wastewater is 1:0.4. The concentration of sulfuric acid in the dilute sulfuric acid is 60%. The pH value of the acidic washing wastewater after the reaction of dilute sulfuric acid and wastewater is 2. The concentration of suspended matter in the wastewater collection tank 7 was 1600mg/L.
Example 7
Example 6 was repeated except that the method included: 5) The concentrated sulfuric acid obtained in step 2) was used for the sale.
Example 8
Example 7 was repeated except that in step 4), compressed air was introduced into the waste water collecting tank 7 while the dilute sulfuric acid reacted with the waste water.
Example 9
Example 8 was repeated except that in step 3), the wastewater in the lower part of the preliminary sedimentation tank 5 was introduced into the wastewater collection tank 7. The wastewater in the lower part of the primary settling tank 5 is also led to a sludge storage tank 9.
Example 10
Example 9 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. In the step 4), the waste gas after the reaction of the dilute sulfuric acid and the waste water is introduced into SO 2 And a desorption column 6.
Example 11
Example 10 was repeated except that in step 3), a part of the wastewater in the upper part of the preliminary sedimentation tank 5 overflowed to SO 2 The other part of the desorption tower 6 overflows to the first-stage washing tower 1. 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 12
Example 11 is repeated, except that in step 3), SO is removed from the wastewater 2 When going to SO 2 The desorption tower 6 is filled with air.
Experiments were conducted according to the external circulation cleaning treatment method for cyanogen-containing SRG gas provided in this example. The amount of wastewater, the concentration of suspended matters in the wastewater, (sulfuric acid, sulfurous acid) salt concentration, the concentration of chloride ions, and the yield of sulfuric acid before the process of this example was measured. Then, the amount of wastewater, the concentration of suspended matters in the wastewater, (sulfuric acid, sulfurous acid) salt concentration, chloride ion concentration, and sulfuric acid yield after the process described in this example were measured.
Detection index Before the process of the embodiment After the process of the embodiment is adopted
Waste water amount, m 3 /h 4 5
Suspension concentration, g/L 3.2 0.1
(sulfuric acid, sulfurous acid) salt concentration, g/L 238 197
Concentration of chloride ion, g/L 40 42
Sulfuric acid yield, t/d 32 39.61

Claims (31)

1. An external circulation cleaning treatment method of cyanide-containing SRG gas, which comprises the following steps:
1) the SRG gas containing cyanide enters a first-stage washing tower (1) from the lower part, and the SRG gas sequentially passes through the first-stage washing tower (1), a second-stage washing tower (2) and a third-stage washing tower (3), wherein: SRG gas is firstly mixed 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, SRG gas is respectively in countercurrent contact with washing solution in each tower, and the washed gas Discharging from the top of the three-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, the process water sequentially passes through the three-stage washing tower (3), a second-stage washing tower (2) and a first-stage washing tower (1) to wash and purify the SRG gas containing cyanide, the wastewater in 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); SO (SO) 2 The desorption tower (6) removes the SO physically dissolved in the wastewater 2 Then discharging the wastewater to a wastewater collection tank (7);
4) Conveying the process water and the concentrated sulfuric acid prepared in the step 2) into a concentrated sulfuric acid diluter (8) for mixing to obtain dilute sulfuric acid; introducing dilute sulfuric acid into a wastewater collection tank (7), reacting the dilute sulfuric acid with wastewater, and discharging acidic washing wastewater after the reaction;
wherein: in the step 3), the wastewater at the lower part of the primary sedimentation tank (5) is introduced into a wastewater collection tank (7); in the step 4), the concentration of sulfuric acid in the dilute sulfuric acid is 30-80%.
2. The method according to claim 1, characterized in that: the method comprises the following steps: 5) The concentrated sulfuric acid obtained in step 2) was used for the sale.
3. The method according to claim 2, characterized in that: in the step 4), compressed air is introduced into a waste water collecting tank (7) when dilute sulfuric acid reacts with waste water; and/or
In the step 3), the wastewater at the lower part of the primary sedimentation tank (5) is also led into a sludge storage tank (9).
4. A method according to any one of claims 1-3, characterized in that: in the step 4), the waste gas after the reaction of the dilute sulfuric acid and the waste water is introduced into SO 2 A desorption column (6); and/or
In step 3), SO in the wastewater is removed 2 At the time, go to SO 2 Air is introduced into the desorption tower (6).
5. A method according to any one of claims 1-3, characterized in that: in the step 3), part of wastewater at the upper part of the primary sedimentation tank (5) enters SO 2 A desorption tower (6), and the other part is led into a first-stage washing tower (1); 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. A method according to any one of claims 1-3, characterized in that: in the step 4), the pH value of the acidic washing wastewater after the reaction of the dilute sulfuric acid and the wastewater is 0-3.
7. The method according to claim 5, wherein: in the step 4), the pH value of the acidic washing wastewater after the reaction of the dilute sulfuric acid and the wastewater is 0-3.
8. The method according to claim 6, wherein: in the step 4), the pH value of the acidic washing wastewater after the reaction of the dilute sulfuric acid and the wastewater is 0.5-2.5.
9. The method according to claim 7, wherein: in the step 4), the pH value of the acidic washing wastewater after the reaction of the dilute sulfuric acid and the wastewater is 0.5-2.5.
10. The method according to claim 8 or 9, characterized in that: in the step 4), the pH value of the acidic washing wastewater after the reaction of the dilute sulfuric acid and the wastewater is 1-2.
11. The method according to any one of claims 7-9, characterized in that: in the step 4), the amount of the dilute sulfuric acid fed into the wastewater collection tank (7) is that the ratio of the molar amount of hydrogen ions in the dilute sulfuric acid to the molar amount of sulfite ions in the wastewater is 1:0.1-1.
12. The method according to claim 11, wherein: in the step 4), the amount of the dilute sulfuric acid fed into the wastewater collection tank (7) is that the ratio of the molar amount of hydrogen ions in the dilute sulfuric acid to the molar amount of sulfite ions in the wastewater is 1:0.2-0.6.
13. The method according to claim 12, wherein: in the step 4), the amount of the dilute sulfuric acid fed into the wastewater collection tank (7) is that the ratio of the molar amount of hydrogen ions in the dilute sulfuric acid to the molar amount of sulfite ions in the wastewater is 1:0.3-0.5.
14. The method according to any one of claims 7-9, 12-13, characterized in that: the concentration of sulfuric acid in the dilute sulfuric acid is 40-70%.
15. The method according to claim 14, wherein: the concentration of sulfuric acid in the dilute sulfuric acid is 50-60%.
16. The method according to any one of claims 1-3, 7-9, 12-13, 15, 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; and/or
In the step 3), the pH value of the liquid discharged from the primary washing tower (1) is 4-6.
17. 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 first-stage washing tower (1) is 2.5-3.5; and/or
In the step 3), the pH value of the liquid discharged from the primary washing tower (1) is 4.5-5.5.
18. The method of any one of claims 1-3, 7-9, 12-13, 15, 17, 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 the step 1), the temperature of the gas discharged from the three-stage washing tower (3) is 10-60 ℃.
19. The method according to claim 18, 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 the step 1), the temperature of the gas discharged from the three-stage washing tower (3) is 20-40 ℃.
20. The method according to claim 19, wherein: in the step 1), the temperature of SRG gas entering the primary washing tower (1) is 380-430 ℃.
21. The method of any one of claims 1-3, 7-9, 12-13, 15, 17, 19-20, 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 the step 3), the temperature of the liquid discharged from the primary washing tower (1) is 50-120 ℃.
22. The method according to claim 21, 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 the step 3), the temperature of the liquid discharged from the primary washing tower (1) is 70-90 ℃.
23. The method of any one of claims 1-3, 7-9, 12-13, 15, 17, 19-20, 22, wherein: the concentration of suspended matters in the wastewater collection tank (7) is 600-2500 mg/L; and/or
In the step 3), the concentration of suspended matters in the wastewater at the upper part of the primary sedimentation tank (5) is 0-100 mg/L.
24. The method according to claim 23, wherein: the concentration of suspended matters in the wastewater collection tank (7) is 800-230mg/L; and/or
In the step 3), the concentration of suspended matters in the wastewater at the upper part of the primary sedimentation tank (5) is 1-80 mg/L.
25. The method according to claim 24, wherein: in the step 3), the concentration of suspended matters in the wastewater at the upper part of the primary sedimentation tank (5) is 2-50 mg/L.
26. A system for cleaning a process for treating a cyanide-containing SRG gas using the method of any of claims 1-25, 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 tower (6), a waste water collecting tank (7) and a concentrated sulfuric acid diluter (8); 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
first conveying pipeline of process water (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 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); SO (SO) 2 The liquid outlet of the desorption tower (6) is connected to a wastewater collection tank (7) via an eighth pipeline (L8); the liquid outlet of the acid making system (4) is connected to a concentrated sulfuric acid diluter (8) via a concentrated sulfuric acid delivery pipe (Lc), a process water second delivery pipe (L d ) Is connected to a concentrated sulfuric acid diluter (8); the liquid outlet of the concentrated sulfuric acid diluter (8) is connected to the liquid inlet of the wastewater collection tank (7) via a ninth pipe (L9).
27. The system according to claim 26, wherein: the compressed air delivery pipe (Le) is connected to the gas inlet of the wastewater collection tank (7); and/or
The bottom liquid outlet of the primary settling tank (5) is connected via a tenth conduit (L10) to the liquid inlet of the wastewater collection tank (7).
28. The system according to claim 27, wherein: an eleventh pipeline (L11) is separated from the tenth pipeline (L10), and the eleventh pipeline (L11) is connected to the sludge storage tank (9).
29. The system according to any one of claims 26-28, wherein: a twelfth pipe (L12) led out from the waste gas outlet of the waste water collecting tank (7) is connected to SO 2 A gas inlet of the desorption column (6); SO (SO) 2 The gas outlet of the desorption column (6) is connected to the first conduit (L1) via a thirteenth conduit (L13).
30. The system according to claim 29, wherein: the air delivery duct (Lf) is connected to the twelfth duct (L12).
31. The system according to any one of claims 26-28, 30, wherein: a fourteenth pipeline (L14) is separated from the seventh pipeline (L7), and the fourteenth pipeline (L14) is connected to an upper liquid inlet of the first-stage washing tower (1); and/or
A fifteenth pipeline (L15) is separated from the fifth pipeline (L5), and the fifteenth pipeline (L15) is connected to an upper liquid inlet of the secondary washing tower (2); a sixteenth pipeline (L16) is separated from the fourth pipeline (L4), and the sixteenth pipeline (L16) is connected to the upper liquid inlet of the three-stage washing tower (3).
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5690899A (en) * 1995-07-29 1997-11-25 Lentjes Bischoff Gmbh Process for removing sulphur dioxide from flue gas
CN1600410A (en) * 2003-09-24 2005-03-30 北京国纬达环保科技有限公司 Integration method for ammonia process of desulfurizing flue gas and multiple utilizing desulfurized products and equipment
CN101723411A (en) * 2009-12-18 2010-06-09 聊城鲁西化工第五化肥厂 Process and equipment for producing potassium sulfate compound fertilizer by integrally utilizing tail gas generated in sulphuric acid production
CN201930584U (en) * 2010-12-29 2011-08-17 攀钢集团钢铁钒钛股份有限公司 Sedimentation tower
CN108939767A (en) * 2018-07-13 2018-12-07 中冶长天国际工程有限责任公司 A method of the purification of the wet high-effective of flue gas containing elemental sulfur
CN109499289A (en) * 2018-11-07 2019-03-22 襄阳泽东化工集团有限公司 A kind of processing method and processing device of desulfidation tail gas
CN110124507A (en) * 2018-02-02 2019-08-16 中冶长天国际工程有限责任公司 A kind of method and device thereof of multi-pollutant flue gas cleaning treatment

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5690899A (en) * 1995-07-29 1997-11-25 Lentjes Bischoff Gmbh Process for removing sulphur dioxide from flue gas
CN1600410A (en) * 2003-09-24 2005-03-30 北京国纬达环保科技有限公司 Integration method for ammonia process of desulfurizing flue gas and multiple utilizing desulfurized products and equipment
CN101723411A (en) * 2009-12-18 2010-06-09 聊城鲁西化工第五化肥厂 Process and equipment for producing potassium sulfate compound fertilizer by integrally utilizing tail gas generated in sulphuric acid production
CN201930584U (en) * 2010-12-29 2011-08-17 攀钢集团钢铁钒钛股份有限公司 Sedimentation tower
CN110124507A (en) * 2018-02-02 2019-08-16 中冶长天国际工程有限责任公司 A kind of method and device thereof of multi-pollutant flue gas cleaning treatment
CN108939767A (en) * 2018-07-13 2018-12-07 中冶长天国际工程有限责任公司 A method of the purification of the wet high-effective of flue gas containing elemental sulfur
CN109499289A (en) * 2018-11-07 2019-03-22 襄阳泽东化工集团有限公司 A kind of processing method and processing device of desulfidation tail gas

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