CN113105012A - Treatment device and method for desulfurization and decyanation waste liquid in coal chemical industry - Google Patents
Treatment device and method for desulfurization and decyanation waste liquid in coal chemical industry Download PDFInfo
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- 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
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D53/1456—Removing acid components
- B01D53/1468—Removing hydrogen sulfide
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- B01D—SEPARATION
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- 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
- B01D53/18—Absorbing units; Liquid distributors therefor
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
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- C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
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- C02F1/72—Treatment of water, waste water, or sewage by oxidation
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Abstract
The invention provides a treatment device and a method for desulfurization and decyanation waste liquid in coal chemical industry, wherein the treatment device comprises a desulfurization and decyanation reaction device, an oxidation reaction device, a decyanation device and a precipitation device which are connected in sequence; the method comprises the following steps: mixing the desulfurization and decyanation waste liquid with a desulfurization and decyanation agent, and then reacting to generate a precipitate to obtain a solid-liquid mixture; adding an oxidant into the obtained solid-liquid mixture to react; adding a decyanation agent into the obtained product, and carrying out precipitation separation after reaction to obtain purified waste liquid. According to the invention, by treating the desulfurization and decyanation waste liquid, the concentration of sulfide in the waste liquid can be reduced to below 10mg/L, and the concentration of cyanide can be reduced to below 50mg/L, so that the water inlet requirement of the subsequent biological treatment of the coal chemical industry waste water is met; simultaneously, device and reagent cost are lower, and application scope is wide, and waste gas and solid waste's processing is compromise simultaneously in the reaction process, green.
Description
Technical Field
The invention belongs to the technical field of wastewater treatment, and relates to a device and a method for treating desulfurization and decyanation waste liquid in coal chemical industry.
Background
H contained in coal gas generated in coal chemical production process2S, HCN, and the like, and combustion products thereof, in order to obtain pure coal gas, the coal gas needs to be desulfurized and decyanated, wherein the vacuum potassium carbonate desulfurization process is a wet desulfurization technology widely applied to the coal gas purification field of large coking enterprises in China. The process adopts K2CO3The solution is used as a desulfurizer to absorb H in the coke oven gas2S, HCN, desorbing the rich solution under vacuum condition to obtain the acid gas, sending to an acid making device to produce sulfuric acid, regenerating the rich solution into a barren solution, and recycling the barren solution in a desulfurizing tower.
In addition to the main reactions of absorption and regeneration, there are also side reactions in the gas purification process, the side reactions can form non-renewable compounds, the main reaction efficiency can be reduced after the non-renewable compounds are accumulated in the gas purification liquid to a certain extent, and in order to ensure the gas purification effect, part of the purification liquid needs to be periodically discharged and KOH needs to be supplemented so as to ensure the gas purification efficiency. The discharged gas purifying liquid contains various highly toxic sulfides, thiocyanide, cyanide and the like, has strong biological toxicity and inhibitive performance on the microorganisms of a biochemical system, and before being discharged into the biochemical system for treatment, the content of toxic substances in the purifying waste liquid must be reduced by adopting a reasonable technical means.
The desulfurized and decyanated waste liquid obtained after gas purification contains sulfides and cyanides with higher concentration, and the treatment method mainly comprises a physical adsorption method, an ion exchange method, a salt extraction method, an advanced oxidation method and a chemical reaction removal method. The physical adsorption method needs to add a large amount of active carbon into the wastewater, the ion exchange method needs a large amount of ion exchange resin, the treatment cost of the two methods is high, and secondary pollution is caused. Salt extraction techniques are technically and economically difficult to implement due to the presence of toxic impurities. Height ofThe treatment process of the staged oxidation method has higher medicament consumption, equipment cost and the whole operation cost of the process; since cyanide also readily forms soluble complexes during wastewater treatment, it is difficult to treat CN in wastewater by chemical precipitation alone-The processing goal is reached. CN 102267769A discloses a method for recycling a vacuum potassium carbonate method coke oven gas desulfurization and decyanation waste liquid, which comprises the steps of simultaneously precipitating cyanide and sulfide by using ferrite, carrying out centrifugal separation, reacting the ferrocyanide precipitate with alkali liquor at a high temperature to convert the ferrocyanide precipitate into a yellow blood salt for dissolution, carrying out centrifugal separation to obtain a yellow blood salt mother solution, then cooling and crystallizing to obtain a yellow blood salt product, and discharging the decyanation and desulfurization waste liquid into a coking wastewater biochemical treatment system for treatment after pH adjustment and dosing coagulation; however, the removal of cyanide and sulfide in waste water is not complete by adopting a single chemical reaction method, and CN in the waste water is difficult to be removed－Reaches a target value. CN 105967391A discloses a treatment device and a method for desulfurization and decyanation of coking waste liquid, which adopt ferrous salt to carry out chemical precipitation, and after separation, supernatant is further oxidized and then flocculated, and the obtained sludge enters a sludge treatment system; the desulfurization and decyanation method relates to an advanced oxidation method, the cost is higher, the sludge generated after treatment is not utilized well, and the utilization rate is low.
In conclusion, a method which is simple in process, low in cost, free of secondary pollution and high in pollutant removal rate needs to be found for treating the desulfurization and decyanation wastewater in the coal chemical industry.
Disclosure of Invention
Aiming at the problems of high operation cost, secondary pollution, high concentration of treated pollutants and incapability of meeting the treatment requirement of a biochemical system and the like in the prior art, the invention aims to provide a treatment device and a treatment method of desulfurization and decyanation waste liquid in coal chemical industry.
In order to achieve the purpose, the invention adopts the following technical scheme:
on one hand, the invention provides a treatment device for desulfurization and decyanation waste liquid in coal chemical industry, which comprises a desulfurization and decyanation reaction device, an oxidation reaction device, a decyanation device and a precipitation device which are connected in sequence.
In the invention, the treatment device is mainly arranged for removing toxic and harmful sulfides and cyanides in the desulfurization and decyanation waste liquid so as to facilitate subsequent operations such as biochemical treatment and the like. Aiming at the characteristics of the desulfurization and decyanation waste liquid, the treatment device of the invention adds corresponding reagents into different devices to sequentially carry out desulfurization and decyanation treatment, oxidation treatment, decyanation treatment and precipitation treatment to remove most S in the waste liquid2-And CN-And the solid-liquid separation of the particles is strengthened, so that the further treatment of the waste liquid is facilitated. The device provided by the invention has the advantages of simple structure, reasonable layout and lower cost, is beneficial to efficient treatment of the desulfurization and decyanation waste liquid, and does not cause secondary pollution.
The following technical solutions are preferred but not limited to the technical solutions provided by the present invention, and the technical objects and advantages of the present invention can be better achieved and realized by the following technical solutions.
As a preferable technical scheme of the invention, the desulfurization and decyanation reaction device is internally provided with a stirring device.
As a preferable technical scheme of the invention, the treatment device further comprises a solid-liquid separation device, a feed inlet of the solid-liquid separation device is connected with a discharge outlet of the oxidation reaction device, and a discharge outlet of the solid-liquid separation device is connected with a feed inlet of the decyanation device.
Preferably, the solid-liquid separation device comprises a plate and frame filter press.
According to the invention, a large amount of insoluble precipitates are generated by the reaction of the desulfurization and decyanation waste liquid and the desulfurization and decyanation agent, then the oxidation of the desulfurization and decyanation agent is carried out by the oxidizing agent, the rest desulfurization and decyanation agent is converted into precipitates, at the moment, the further treatment of the rest cyanides in the waste liquid can be influenced by the existence of a large amount of precipitates in the waste liquid, so that solid-liquid separation is required, a plate-and-frame filter press is preferably selected, the separation effect is good, the separation effect can be ensured even if the generated inorganic precipitates have small particles, the density is close to that of water and the hydrophilicity is strong, the precipitated sludge is separated out and then is treated independently, and the.
As a preferable technical scheme of the invention, the treatment device further comprises a gas collecting device and a gas treatment device, wherein gas outlets of the desulfurization and decyanation reaction device, the oxidation reaction device, the decyanation device and the solid-liquid separation device are all connected with a gas inlet of the gas collecting device, a gas outlet of the gas collecting device is connected with a gas inlet of the gas treatment device, and a liquid outlet of the gas absorption device is connected with the desulfurization and decyanation reaction device;
in the invention, during the treatment process of the desulfurization and decyanation waste liquid, H may exist2S, HCN, the direct discharge brings great harm to environment and organism, so the gas collecting device is arranged at the top of each device, the gas is concentrated and then treated under the action of the centrifugal fan, the treated gas can be emptied and treated, and the used absorption liquid is treated together with the desulfurization and decyanation waste liquid due to the reason of absorbing harmful gas.
Preferably, the gas collection means comprises a centrifugal fan.
Preferably, the gas treatment plant comprises a tail gas absorber.
On the other hand, the invention provides a method for treating desulfurization and decyanation waste liquid in coal chemical industry by using the device, which comprises the following steps:
(1) mixing the desulfurization and decyanation waste liquid with a desulfurization and decyanation agent, and then reacting to generate a precipitate to obtain a solid-liquid mixture;
(2) adding an oxidant into the solid-liquid mixture obtained in the step (1) to react;
(3) and (3) adding a decyanation agent into the product obtained in the step (2), and carrying out precipitation separation after reaction to obtain purified waste liquid.
In the invention, the desulfurization and decyanation waste liquid reacts with the desulfurization and decyanation agent to generate insoluble precipitate which can remove toxic and harmful S2-And most of CN-Is removed due to the desulfurization and decyanation agent and CN-The precipitate generated by the reaction can partially continue to react to generate the coordination cyanide to be dissolved; the oxidant is added to oxidize the residual desulphurization and decyanation agent, and then the residual desulphurization and decyanation agent is converted into precipitate; then adding decyanation agent to remove residual CN fully-And separating the precipitate to obtain purified waste liquid for subsequent treatment.
As a preferred technical scheme of the invention, the concentration of the sulfide in the desulfurization and decyanation waste liquid in the step (1) is 3000-5000 mg/L, such as 3000mg/L, 3500mg/L, 4000mg/L, 4500mg/L or 5000mg/L, but the invention is not limited to the values listed, and other values not listed in the range of the values are also applicable; the cyanide concentration is 1000-3000 mg/L, such as 1000mg/L, 1500mg/L, 2000mg/L, 2500mg/L or 3000mg/L, but not limited to the values listed, and other values not listed within the range of values are also applicable.
In the present invention, the sulfide is mainly S2-Also includes a small amount of SO3 2-And S2O3 2-Cyanide is predominantly CN-Besides, the waste liquor also contains a small quantity of thiocyanide, and uses SCN-Mainly comprises the following steps.
Preferably, the components of the desulfurization and decyanation agent in the step (1) comprise ferrous ions.
Preferably, the components of the desulfurization and decyanation agent in the step (1) further comprise iron ions and/or copper ions.
In the invention, the desulfurization and decyanation agent comprises Fe2+And S2-And CN-Can generate precipitate, while the ferrous cyanide precipitate can continuously react to generate complex to be dissolved, the copper ion can also generate precipitate correspondingly, and if the iron ion is added, the complex generated before can be converted into precipitate again, which is beneficial to removing CN-。
Preferably, the amount of the desulfurization and decyanation agent added in step (1) is 0.05 to 0.55 wt%, such as 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, or 0.55 wt% of the mass of the desulfurization and decyanation waste liquid, but is not limited to the recited values, and other non-recited values in the range of the values are also applicable.
In the invention, the addition of the desulfurization and decyanation agent is one of the influencing factors of waste liquid treatment, and if the addition of the desulfurization and decyanation agent is too large, the desulfurization and decyanation agent is wasted; if the addition amount of the desulfurization and decyanation agent is too small, CN-The excessive amount of the iron cyanide precipitate dissolves the generated iron cyanide precipitate, so that the removal of the sulfide and the cyanide in the wastewater does not reach the standard.
Preferably, the reaction in the step (1) is carried out in a desulfurization and decyanation reaction device.
Preferably, the reaction time in step (1) is 5-30 min, such as 5min, 10min, 15min, 20min, 25min or 30min, but not limited to the recited values, and other values not recited in the range of the values are also applicable.
As a preferred technical scheme of the invention, the oxidant in the step (2) comprises air.
In the present invention, the remaining Fe may be added by adding an oxidizing agent2+Oxidation to Fe3+Can be converted into ferric hydroxide precipitate under the condition of lower pH, and simultaneously Fe3+Part of the coordination cyanide can also be converted into a prussian blue precipitate.
Preferably, the reaction time in step (2) is 5-30 min, such as 5min, 10min, 15min, 20min, 25min or 30min, but not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the reaction of step (2) is carried out in an oxidation reaction apparatus.
Preferably, after the reaction in step (2) is finished, solid-liquid separation is firstly carried out to obtain solid sludge and waste liquid, and the obtained waste liquid is continuously treated.
Preferably, the solid-liquid separation adopts a plate-and-frame filter pressing mode.
According to the invention, a large amount of insoluble precipitate can be generated through a sulphur decyanation reaction and an oxidation reaction, and further treatment of residual cyanide in the waste liquid can be influenced, so that solid-liquid separation is required, plate-and-frame filter pressing is preferably selected, even if the generated inorganic precipitate has small particles, density close to that of water and strong hydrophilicity, the separation effect can be ensured, the precipitated sludge is separated and then treated independently, and the residual waste liquid is subjected to subsequent treatment.
As a preferable technical scheme of the invention, the decyanation agent in the step (3) comprises a colloidal material.
Preferably, the colloidal material is an organic-inorganic composite material.
In the invention, the decyanation agent is selected from a colloidal material which has stronger adsorption effect and particularly has stronger adsorption effect on CN which mainly exists in the form of coordination cyanide-Thereby deeply removing the cyanide in the waste liquid and ensuring the removal effect of the cyanide.
Preferably, the decyanation agent in step (3) is added in an amount of 0.01 to 0.1 wt%, such as 0.01 wt%, 0.03 wt%, 0.05 wt%, 0.06 wt%, 0.08 wt%, or 0.1 wt% of the mass of the waste liquid obtained in step (2), but not limited to the recited values, and other non-recited values in the range of the recited values are also applicable.
Preferably, the reaction of step (3) is carried out in a decyanation apparatus.
Preferably, the precipitation separation of step (3) is performed in a precipitation device.
Preferably, a nucleating agent is added into the precipitation device, specifically anthracite and/or quartz sand can be selected, and the particle size range of the nucleating agent is 200-500 meshes, such as 200 meshes, 250 meshes, 300 meshes, 350 meshes, 400 meshes, 450 meshes or 500 meshes.
In the invention, after decyanation treatment, because the particle size of the colloid material is not too small, solid particles obtained after adsorption have the same particle size and lower density, and are difficult to separate effectively by simple solid-liquid separation, the particles are aggregated and grow under the action of the special nucleating agent according to the physicochemical properties of the particles to form flocs, thereby ensuring the precipitation effect and facilitating the separation from waste liquid.
As a preferable technical scheme of the invention, the gas generated in the desulfurization and decyanation waste liquid treatment process is collected and then is subjected to purification treatment.
Preferably, the gas is collected using a centrifugal fan.
Preferably, the purification treatment is performed in a tail gas absorption tower.
Preferably, the tail gas absorption tower is internally added with absorption liquid.
Preferably, the components of the absorption liquid comprise sodium hydroxide and/or sodium carbonate.
Preferably, the absorption liquid after being purified is treated in the step (1).
In the invention, during the treatment process of the desulfurization and decyanation waste liquid, H may exist2S, HCN, the gas is collected from the top of each device, the gas is concentrated by the centrifugal fan and then absorbed by the absorption liquid, the treated gas can be emptied, and the used absorption liquid is mixed with the desulfurization and decyanation waste liquid for treating the harmful gas.
As a preferred technical scheme of the invention, the method comprises the following steps:
(1) mixing the desulfurization and decyanation waste liquid with a desulfurization and decyanation agent, wherein the concentration of sulfide in the desulfurization and decyanation waste liquid is 3000-5000 mg/L, the concentration of cyanide is 1000-3000 mg/L, the components of the desulfurization and decyanation agent comprise ferrous ions, the addition amount of the ferrous ions is 0.05-0.55 wt% of the mass of the desulfurization and decyanation waste liquid, reacting for 5-30 min, and generating a precipitate to obtain a solid-liquid mixture;
(2) adding an oxidant into the solid-liquid mixture obtained in the step (1), reacting for 5-30 min, and performing plate-and-frame filter pressing to obtain solid sludge and waste liquid;
(3) adding a decyanation agent into the waste liquid obtained in the step (2), wherein the decyanation agent comprises a colloidal material, the addition amount of the decyanation agent is 0.01-0.1 wt% of the mass of the obtained waste liquid, adding a nucleating agent after reaction decyanation, and carrying out precipitation separation to obtain the purified waste liquid;
(4) collecting gas generated in the reaction processes of the steps (1), (2) and (3), purifying the gas by using an absorption liquid, discharging the purified gas, and treating the absorption liquid subjected to gas purification in the step (1).
The method is suitable for treating the wastewater in the coal chemical industry fields such as coal coking, coal gasification, low-grade coal utilization and the like.
Compared with the prior art, the invention has the following beneficial effects:
(1) the desulfurization and decyanation waste liquid is treated in a targeted manner through reasonable connection of the treatment devices, the concentration of sulfide in the waste liquid can be reduced to be below 10mg/L, and the concentration of cyanide can be reduced to be below 50mg/L, so that the water inlet requirement of subsequent biological treatment of the coal chemical industry waste water is met;
(2) the device and the reagent have the advantages of low cost, wide application range, green and environment-friendly treatment of waste gas and solid waste in the reaction process.
Drawings
FIG. 1 is a process flow diagram of a method for treating a desulfurization and decyanation waste liquid in coal chemical industry according to embodiment 2 of the present invention.
Detailed Description
In order to better illustrate the present invention and facilitate the understanding of the technical solutions, the present invention is further described in detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.
The specific embodiment of the invention provides a treatment device and a method for desulfurization and decyanation waste liquid in coal chemical industry, wherein the treatment device comprises a desulfurization and decyanation reaction device, an oxidation reaction device, a decyanation device and a precipitation device which are connected in sequence;
the method comprises the following steps:
(1) mixing the desulfurization and decyanation waste liquid with a desulfurization and decyanation agent, and then reacting to generate a precipitate to obtain a solid-liquid mixture;
(2) adding an oxidant into the solid-liquid mixture obtained in the step (1) to react;
(3) and (3) adding a decyanation agent into the product obtained in the step (2), and carrying out precipitation separation after reaction to obtain purified waste liquid.
The following are typical but non-limiting examples of the invention:
example 1:
the embodiment provides a coal industry desulfurization decyanation waste liquid processing apparatus, processing apparatus is including desulfurization decyanation reaction device, oxidation reaction device, decyanation device and the precipitation apparatus that connects gradually.
Wherein, a stirring device is arranged in the desulfurization and decyanation reaction device.
The treatment device also comprises a solid-liquid separation device, wherein a feed inlet of the solid-liquid separation device is connected with a discharge outlet of the oxidation reaction device, and a discharge outlet of the solid-liquid separation device is connected with a feed inlet of the decyanation device; the solid-liquid separation device is a plate-and-frame filter press.
The treatment device also comprises a gas collecting device and a gas treatment device, wherein gas outlets of the desulfurization and decyanation reaction device, the oxidation reaction device, the decyanation device and the solid-liquid separation device are all connected with a gas inlet of the gas collecting device, a gas outlet of the gas collecting device is connected with a gas inlet of the gas treatment device, and a liquid outlet of the gas absorption device is connected with the desulfurization and decyanation reaction device;
the gas collecting device is a centrifugal fan, and the gas processing device comprises a tail gas absorption tower.
Example 2:
the embodiment provides a method for treating desulfurization and decyanation waste liquid in coal chemical industry, which is carried out in the device in embodiment 1, and the process flow diagram of the method is shown in fig. 1, and the method comprises the following steps:
(1) mixing the desulfurization and decyanation waste liquid and ferrous sulfate in a desulfurization and decyanation reaction device, wherein the concentration of sulfide in the desulfurization and decyanation waste liquid is 3000mg/L, the concentration of cyanide is 1000mg/L, and the mass fraction of the ferrous sulfate in the desulfurization and decyanation waste liquid is 0.25 wt%, reacting for 20min to generate a precipitate, and thus obtaining a solid-liquid mixture;
(2) introducing oxygen into the solid-liquid mixture obtained in the step (1), reacting in an oxidation reaction device for 20min, and then carrying out plate-and-frame filter pressing to obtain solid sludge and waste liquid;
(3) enabling the waste liquid obtained in the step (2) to enter a decyanation device, adding a colloid material, wherein the addition amount of the colloid material accounts for 0.05 wt% of the mass of the waste liquid, enabling the waste liquid to enter a precipitation device after reaction decyanation, adding quartz sand serving as a nucleating agent, aggregating to form a precipitate, and separating to obtain purified waste liquid;
(4) collecting gas generated in the reaction processes of the steps (1), (2) and (3), purifying the gas by using sodium hydroxide absorption liquid in a tail gas absorption tower, discharging the purified gas, and treating the purified gas absorption liquid in the step (1).
In this example, after the desulfurization and decyanation treatment, the sulfide concentration in the purified waste liquid was reduced to 6mg/L, and the cyanide concentration was reduced to 32 mg/L.
Example 3:
the embodiment provides a method for treating desulfurization and decyanation waste liquid in coal chemical industry, which is carried out in the device in embodiment 1, and comprises the following steps:
(1) mixing the desulfurization and decyanation waste liquid with a desulfurization and decyanation agent, wherein the concentration of sulfide in the desulfurization and decyanation waste liquid is 4000mg/L, the concentration of cyanide is 1500mg/L, the desulfurization and decyanation agent is a mixture of ferrous sulfate and copper sulfate with the mass ratio of 1:1, the mass fraction of the mixture in the desulfurization and decyanation waste liquid is 0.1 wt%, and reacting for 30min to generate a precipitate to obtain a solid-liquid mixture;
(2) introducing oxygen into the solid-liquid mixture obtained in the step (1), reacting in an oxidation reaction device for 10min, and then carrying out plate-and-frame filter pressing to obtain solid sludge and waste liquid;
(3) enabling the waste liquid obtained in the step (2) to enter a decyanation device, adding a colloid material, wherein the addition amount of the colloid material accounts for 0.1 wt% of the mass of the waste liquid, enabling the waste liquid to enter a precipitation device after reaction decyanation, adding anthracite as a nucleating agent, aggregating to form a precipitate, and separating to obtain purified waste liquid;
(4) collecting the gas generated in the reaction process of the steps (1), (2) and (3), purifying the gas by using a sodium carbonate absorption liquid in a tail gas absorption tower, discharging the purified gas, and treating the purified gas absorption liquid in the step (1).
In this embodiment, after the desulfurization and decyanation treatment, the sulfide concentration in the waste purification solution was reduced to 10mg/L, and the cyanide concentration was reduced to 38 mg/L.
Example 4:
the embodiment provides a method for treating desulfurization and decyanation waste liquid in coal chemical industry, which is carried out in the device in embodiment 1, and comprises the following steps:
(1) mixing the desulfurization and decyanation waste liquid with a desulfurization and decyanation agent, wherein the concentration of sulfide in the desulfurization and decyanation waste liquid is 5000mg/L, the concentration of cyanide is 2500mg/L, the desulfurization and decyanation agent is ferrous sulfate, the mass fraction of the desulfurization and decyanation waste liquid is 0.55 wt%, reacting for 10min, and generating a precipitate to obtain a solid-liquid mixture;
(2) introducing oxygen into the solid-liquid mixture obtained in the step (1), reacting in an oxidation reaction device for 30min, and then carrying out plate-and-frame filter pressing to obtain solid sludge and waste liquid;
(3) enabling the waste liquid obtained in the step (2) to enter a decyanation device, adding a colloid material, wherein the addition amount of the colloid material accounts for 0.02 wt% of the mass of the waste liquid, enabling the waste liquid to enter a precipitation device after reaction decyanation, adding quartz sand serving as a nucleating agent, aggregating to form a precipitate, and separating to obtain purified waste liquid;
(4) collecting the gas generated in the reaction process of the steps (1), (2) and (3), purifying the gas by using a sodium carbonate absorption liquid in a tail gas absorption tower, discharging the purified gas, and treating the purified gas absorption liquid in the step (1).
In this example, after the desulfurization and decyanation treatment, the sulfide concentration in the purified waste liquid was reduced to 5mg/L, and the cyanide concentration was reduced to 41 mg/L.
Example 5:
the embodiment provides a method for treating desulfurization and decyanation waste liquid in coal chemical industry, which is carried out in the device in embodiment 1, and comprises the following steps:
(1) mixing the desulfurization and decyanation waste liquid with a desulfurization and decyanation agent, wherein the concentration of sulfide in the desulfurization and decyanation waste liquid is 3500mg/L, the concentration of cyanide is 2000mg/L, the desulfurization and decyanation agent is a mixture of ferrous sulfate and ferric sulfate in a mass ratio of 3:1, the mass fraction of the mixture in the desulfurization and decyanation waste liquid is 0.4 wt%, and reacting for 15min to generate a precipitate to obtain a solid-liquid mixture;
(2) introducing oxygen into the solid-liquid mixture obtained in the step (1), reacting in an oxidation reaction device for 5min, and then carrying out plate-and-frame filter pressing to obtain solid sludge and waste liquid;
(3) enabling the waste liquid obtained in the step (2) to enter a decyanation device, adding a colloid material, wherein the addition amount of the colloid material accounts for 0.08 wt% of the mass of the waste liquid, enabling the waste liquid to enter a precipitation device after reaction decyanation, adding anthracite as a nucleating agent, aggregating to form a precipitate, and separating to obtain purified waste liquid;
(4) collecting the gas generated in the reaction process of the steps (1), (2) and (3), purifying the gas by using a sodium carbonate absorption liquid in a tail gas absorption tower, discharging the purified gas, and treating the purified gas absorption liquid in the step (1).
In this example, after the desulfurization and decyanation treatment, the sulfide concentration in the purified waste liquid was reduced to 9mg/L, and the cyanide concentration was reduced to 45 mg/L.
Example 6:
this example provides a method for treating desulfurization and decyanation waste liquid in coal chemical industry, which is similar to the method in example 2, except that: the mass proportion of the ferrous sulfate in the desulfurization and decyanation waste liquid in the step (1) is 0.03 wt%, namely the addition amount of the desulfurization and decyanation agent is smaller.
In the embodiment, because the addition amount of the desulfurization and decyanation agent is small, the addition amount of the desulfurization and decyanation agent is not enough to completely convert pollutants, the generated ferrous cyanide precipitate may be converted into a complex to be dissolved, and after the desulfurization and decyanation treatment, the concentration of sulfide in the purification waste liquid is 18mg/L, and the concentration of cyanide is 60 mg/L.
Example 7:
the embodiment provides a device and a method for treating desulfurization and decyanation waste liquid in coal chemical industry, which refer to the device in embodiment 1 and are different only in that: the apparatus does not include a gas collection device and a gas treatment device.
The process is referred to the process in example 2, with the only difference that: the process of step (4) is not included.
In this embodiment, because not set up gas collection device and gas processing apparatus, although the waste liquid after the processing satisfies follow-up biological treatment's requirement of intaking, the poisonous and harmful gas that produces among the waste liquid treatment process can directly discharge, causes the pollution to the environment, does not accord with the requirement of environmental protection technology.
Comparative example 1:
the comparative example provides a coal chemical industry desulfurization and decyanation waste liquid treatment device and a method, and the device is as the device in example 1, and the difference is only that: the apparatus does not include a decyanation apparatus and a precipitation apparatus.
The process is referred to the process in example 2, with the only difference that: the process of step (3) is not included.
In the comparative example, because decyanation treatment is not carried out again, the treatment of sulfide and cyanide in the waste liquid, especially cyanide, is not thorough, the concentration of sulfide in the final waste liquid is still 25mg/L, and the concentration of cyanide is still 100mg/L, so that the water inlet requirement of subsequent biological treatment is not met.
The embodiment and the comparative example are integrated, so that the desulfurization and decyanation waste liquid is treated in a targeted manner through reasonable connection of the treatment devices, the concentration of sulfide in the waste liquid can be reduced to be below 10mg/L, the concentration of cyanide can be reduced to be below 50mg/L, and the water inlet requirement of the subsequent biological treatment of the coal chemical industry waste water is met; simultaneously, device and reagent cost are lower, and application scope is wide, and waste gas and solid waste's processing is compromise simultaneously in the reaction process, green.
The applicant states that the present invention is illustrated by the above embodiments of the treatment apparatus and process of the present invention, but the present invention is not limited to the above apparatus and process, i.e. it does not mean that the present invention must be implemented by the above apparatus and process. It will be apparent to those skilled in the art that any modifications to the present invention, equivalent alterations to the structure of the device of the present invention and additional devices, additions of components, choices of specific means, etc., are within the scope and disclosure of the present invention.
Claims (10)
1. The utility model provides a processing apparatus of coal industry desulfurization decyanation waste liquid which characterized in that, processing apparatus is including desulfurization decyanation reaction unit, oxidation reaction unit, decyanation device and the precipitation unit that connects gradually.
2. The processing device according to claim 1, wherein a stirring device is arranged in the desulfurization and decyanation reaction device.
3. The treatment device according to claim 1 or 2, further comprising a solid-liquid separation device, wherein a feed inlet of the solid-liquid separation device is connected with a discharge outlet of the oxidation reaction device, and a discharge outlet of the solid-liquid separation device is connected with a feed inlet of the decyanation device;
preferably, the solid-liquid separation device comprises a plate and frame filter press.
4. The treatment device according to claim 3, further comprising a gas collecting device and a gas treatment device, wherein gas outlets of the desulfurization and decyanation reaction device, the oxidation reaction device, the decyanation device and the solid-liquid separation device are all connected with a gas inlet of the gas collecting device, a gas outlet of the gas collecting device is connected with a gas inlet of the gas treatment device, and a liquid outlet of the gas absorption device is connected with the desulfurization and decyanation reaction device;
preferably, the gas collection means comprises a centrifugal fan;
preferably, the gas treatment plant comprises a tail gas absorber.
5. A method for treating desulfurization and decyanation waste liquid in coal chemical industry by using the device of any one of claims 1-4, which is characterized by comprising the following steps:
(1) mixing the desulfurization and decyanation waste liquid with a desulfurization and decyanation agent, and then reacting to generate a precipitate to obtain a solid-liquid mixture;
(2) adding an oxidant into the solid-liquid mixture obtained in the step (1) to react;
(3) and (3) adding a decyanation agent into the product obtained in the step (2), and carrying out precipitation separation after reaction to obtain purified waste liquid.
6. The method according to claim 5, wherein the concentration of sulfide in the desulfurization and decyanation waste liquid in the step (1) is 3000-5000 mg/L, and the concentration of cyanide is 1000-3000 mg/L;
preferably, the components of the desulfurization and decyanation agent in the step (1) comprise ferrous ions;
preferably, the components of the desulfurization and decyanation agent in the step (1) also comprise iron ions and/or copper ions;
preferably, the addition amount of the desulfurization and decyanation agent in the step (1) is 0.05-0.55 wt% of the mass of the desulfurization and decyanation waste liquid;
preferably, the reaction in the step (1) is carried out in a desulfurization and decyanation reaction device;
preferably, the reaction time in the step (1) is 5-30 min.
7. The method of claim 5 or 6, wherein the oxidant of step (2) comprises air;
preferably, the reaction time in the step (2) is 5-30 min;
preferably, the reaction of step (2) is carried out in an oxidation reaction device;
preferably, after the reaction in the step (2) is finished, performing solid-liquid separation to obtain solid sludge and waste liquid, and continuously treating the obtained waste liquid;
preferably, the solid-liquid separation adopts a plate-and-frame filter pressing mode.
8. The method according to any one of claims 5 to 7, wherein the decyanation agent of step (3) comprises a colloidal material;
preferably, the colloidal material is an organic-inorganic composite material;
preferably, the addition amount of the decyanation agent in the step (3) is 0.01-0.1 wt% of the mass of the waste liquid obtained in the step (2);
preferably, the reaction of step (3) is carried out in a decyanation device;
preferably, the precipitation separation of step (3) is carried out in a precipitation device;
preferably, a nucleating agent is added into the precipitation device;
preferably, the nucleating agent comprises anthracite and/or quartz sand.
9. The method according to any one of claims 5 to 8, wherein the gas generated in the desulfurization and decyanation waste liquid treatment process is collected and then subjected to purification treatment;
preferably, the gas is collected using a centrifugal fan;
preferably, the purification treatment is carried out in a tail gas absorption tower;
preferably, the tail gas absorption tower is internally added with absorption liquid;
preferably, the components of the absorption liquid comprise sodium hydroxide and/or sodium carbonate;
preferably, the absorption liquid after being purified is treated in the step (1).
10. Method according to any of claims 5-9, characterized in that the method comprises the steps of:
(1) mixing the desulfurization and decyanation waste liquid with a desulfurization and decyanation agent, wherein the concentration of sulfide in the desulfurization and decyanation waste liquid is 3000-5000 mg/L, the concentration of cyanide is 1000-3000 mg/L, the components of the desulfurization and decyanation agent comprise ferrous ions, the addition amount of the ferrous ions is 0.05-0.55 wt% of the mass of the desulfurization and decyanation waste liquid, reacting for 5-30 min, and generating a precipitate to obtain a solid-liquid mixture;
(2) adding an oxidant into the solid-liquid mixture obtained in the step (1), reacting for 5-30 min, and performing plate-and-frame filter pressing to obtain solid sludge and waste liquid;
(3) adding a decyanation agent into the waste liquid obtained in the step (2), wherein the decyanation agent comprises a colloidal material, the addition amount of the decyanation agent is 0.01-0.1 wt% of the mass of the obtained waste liquid, adding a nucleating agent after reaction decyanation, and carrying out precipitation separation to obtain the purified waste liquid;
(4) collecting gas generated in the reaction processes of the steps (1), (2) and (3), purifying the gas by using an absorption liquid, discharging the purified gas, and treating the absorption liquid subjected to gas purification in the step (1).
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113797601A (en) * | 2021-09-17 | 2021-12-17 | 张友成 | Desulfurizing liquid desorption cooling tower |
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