CN110563539A - Treatment process and equipment for high-concentration wastewater generated in production of styrene from methanol and toluene - Google Patents

Treatment process and equipment for high-concentration wastewater generated in production of styrene from methanol and toluene Download PDF

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Publication number
CN110563539A
CN110563539A CN201910846425.7A CN201910846425A CN110563539A CN 110563539 A CN110563539 A CN 110563539A CN 201910846425 A CN201910846425 A CN 201910846425A CN 110563539 A CN110563539 A CN 110563539A
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styrene
concentration
tower
methanol
toluene
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谭亚南
曹琨
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Neijiang Normal University
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Neijiang Normal University
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    • 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
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/005—Processes comprising at least two steps in series
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/04—Purification; Separation; Use of additives by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/20—Use of additives, e.g. for stabilisation
    • 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
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • 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
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C02F1/048—Purification of waste water by evaporation
    • 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
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5281—Installations for water purification using chemical agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • 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
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
    • C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/08—Multistage treatments, e.g. repetition of the same process step under different conditions

Abstract

the invention discloses a treatment process and equipment for styrene high-concentration wastewater produced by methanol toluene, wherein the process comprises the following steps: adding a flocculating agent into the high-concentration wastewater generated in the production of styrene from methanol and toluene for flocculation treatment to obtain flocculated wastewater; carrying out triple filtration on the flocculated wastewater to obtain filter residue and filtrate; performing primary rectification separation on the filtrate to obtain a high-concentration ethylbenzene solution and a high-concentration styrene solution; performing secondary rectification separation on the high-concentration ethylbenzene solution to obtain a methanol-toluene mixed solution and a high-purity ethylbenzene solution; and refining and separating the high-concentration styrene solution to obtain high-purity styrene and catalyst powder. The treatment equipment comprises a wastewater flocculation treatment unit, a triple filtration unit, a separation unit and a post-treatment unit which are connected in sequence. The technology of the invention greatly reduces inorganic/organic discharge amount, even zero discharge, realizes a new environment-friendly wastewater treatment process, and further improves economic benefit.

Description

Treatment process and equipment for high-concentration wastewater generated in production of styrene from methanol and toluene
Technical Field
The invention belongs to the field of industrial wastewater treatment, and particularly relates to a treatment process and equipment for high-concentration wastewater generated in the production of styrene from methanol and toluene, wherein components contained in the high-concentration wastewater are recycled by adopting flocculation precipitation, filtration, separation and post-treatment processes.
background
In the modern chemical industry, styrene is used as an important organic synthetic raw material and widely applied to the production of polystyrene, styrene-butadiene rubber, ion exchange resin, medicines, dyes and the like, and the output of a series of chemical materials is second to the output of high-yield polymers in the world and is in front of the output of synthetic resins in the world.
The traditional styrene production process is mainly used for producing ethylbenzene from benzene and ethylene and then preparing styrene products through catalytic dehydrogenation, and has the defects of long route, high temperature of a catalyst bed layer (600-660 ℃), high energy consumption, high raw material cost and the like. The methanol and the toluene can be used for preparing the styrene (coproducing the ethylbenzene) through the side chain alkylation reaction, and the method is a novel process which is mainly concerned by researchers in recent years, in particular to a methanol and toluene side chain alkylation process technology. For example, in patent CN103664485A, a process for producing styrene and ethylbenzene by side chain alkylation of methanol and toluene is developed, which solves the problem of low comprehensive yield of methanol, but because the catalytic reaction is an acid-base concerted catalytic reaction, usually an X-type or Y-type low silica-alumina ratio molecular sieve is used as a main active component of the catalyst, the production cost of styrene is greatly reduced by the technology.
However, the reaction for producing styrene by the process is the same as other catalytic reactions, and process steam containing catalyst powder, raw materials (methanol and toluene), styrene and ethylbenzene can be obtained, the temperature is up to more than 200 ℃, if the temperature is directly reduced to a lower temperature, higher organic matters can be contained in process wastewater, the difficulty in wastewater treatment is increased, the wastewater treatment at the present stage is usually single wastewater discharge and then is sent to an independent wastewater treatment system, and the wastewater is discharged after reaching the standard or discharged into an industrial park wastewater treatment system. The treatment of the wastewater is required to be harmonious and unified with the process, and the micro-discharge and even the zero-discharge are realized on the premise of greatly reducing the new water consumption and the terminal sewage discharge.
Even if the primary treatment is carried out, the obtained process wastewater still contains a large amount of organic matters and catalyst powder and has high pollutant content, so a new process wastewater technology needs to be designed and invented for treatment.
disclosure of Invention
The invention aims to solve the problems and provide an environment-friendly treatment process of high-concentration wastewater from styrene production by methanol and toluene, which has zero inorganic/organic waste discharge.
The invention provides a treatment process of high-concentration wastewater from production of styrene by methanol and toluene, which comprises the following steps:
A. Adding a flocculating agent into the high-concentration wastewater generated in the production of styrene from methanol and toluene for flocculation treatment to obtain flocculated wastewater, wherein the COD value of the high-concentration wastewater generated in the production of styrene from methanol and toluene is above 4500 mg/L;
B. Carrying out triple filtration on the flocculated wastewater to obtain filter residue and filtrate;
C. Performing primary rectification separation on the filtrate to obtain a high-concentration ethylbenzene solution and a high-concentration styrene solution; performing secondary rectification separation on the high-concentration ethylbenzene solution to obtain a methanol-toluene mixed solution and a high-purity ethylbenzene solution; and refining and separating the high-concentration styrene solution to obtain high-purity styrene and catalyst powder.
According to one embodiment of the treatment process for producing high-concentration styrene wastewater by using methyl alcohol and toluene, in the step A, the flocculant is one or more of aluminum sulfate, ferric sulfate, hydroxypropyl methyl cellulose and polyacrylamide, the flocculant is added in a solution form, and the concentration of the flocculant solution is 0.1-0.2%; the volume ratio of the flocculant solution to the high-concentration wastewater generated in the production of styrene from methanol and toluene is 1: 400-1: 5000, the flocculation time is controlled to be 0.5-10 h, and the stirring speed is 10-250 r/min.
According to an embodiment of the treatment process for high-concentration wastewater generated in the production of styrene from methanol and toluene, in the step B, the triple filtration comprises mechanical filtration, filter screen filtration and security filtration which are sequentially performed, wherein the filtration rate of the mechanical filtration is 1-20 m3h and preferably 5 to 12m3The filtering precision of the filter screen is 200-1000 meshes, preferably 600-800 meshes, and the filtering precision of security filtration is 5-20 mu m.
According to an embodiment of the treatment process for producing high-concentration styrene wastewater from methanol and toluene, in the step C, the primary rectification separation is performed by a primary rectification tower, the tower bottom operating temperature is controlled to be 80-100 ℃, the tower bottom operating pressure is controlled to be 20-40 kPa, the tower top operating temperature is controlled to be 65-90 ℃, the tower top operating pressure is controlled to be 10-30 kPa, the tower top reflux ratio is controlled to be 5-12, a high-concentration ethylbenzene solution is obtained from the tower top, and a high-concentration styrene solution is obtained from the tower bottom.
According to an embodiment of the treatment process for producing high-concentration styrene wastewater from methanol and toluene, in the step C, the second-stage rectification separation is performed by a second-stage rectification tower, the operation temperature is controlled to be 70-90 ℃, the operation pressure is controlled to be 90-150 kPa, the reflux ratio at the top of the tower is controlled to be 1-10, a methanol and toluene mixed solution is obtained from the top of the tower, and a high-concentration ethylbenzene solution is obtained from the bottom of the tower.
According to an embodiment of the treatment process for high-concentration wastewater from styrene production by methanol toluene, in step C, the refining separation is performed by a styrene rectifying tower, the operation temperature of the tower top is controlled to be 70-90 ℃, the operation pressure is controlled to be 4-20 kPa, the operation temperature of the tower bottom is controlled to be 80-100 ℃, the operation pressure is controlled to be 8-30 kPa, high-purity styrene products are obtained from the tower top, and catalyst powder rich in tar is obtained from the tower bottom.
According to one embodiment of the treatment process for producing high-concentration styrene wastewater from methanol toluene, in step C, the high-purity styrene is subjected to water absorption treatment by anhydrous sodium sulfate to obtain a high-purity styrene product, and the sodium sulfate after water absorption is recycled; and purifying the methanol-toluene mixed solution and the high-purity ethylbenzene solution, and recycling the purified methanol-toluene mixed solution and the high-purity ethylbenzene solution as industrial raw materials.
According to one embodiment of the treatment process for producing high-concentration styrene wastewater by using methanol and toluene, the catalyst powder obtained in the step C and the filter residue obtained in the step B are mixed, dried at the temperature of 100-130 ℃ for 4-6 h, heated to the temperature of 400-450 ℃, roasted for 2-4 h, and then filled into a methanol and toluene side alkane reactor for recycling.
The invention provides a treatment device for high-concentration wastewater generated in the production of styrene from methanol and toluene, which comprises a flocculation treatment unit, a triple filtration unit, a separation unit and a post-treatment unit which are sequentially connected, wherein the triple filtration unit comprises a mechanical filter, a filter screen filter and a security filter which are sequentially connected, the separation unit comprises a primary rectifying tower, a secondary rectifying tower and a styrene rectifying tower, the outlet of the top of the primary rectifying tower is connected with the inlet of the secondary rectifying tower, and the outlet of the bottom of the primary rectifying tower is connected with the styrene rectifying tower.
According to one embodiment of the treatment equipment for producing the high-concentration styrene wastewater by using the methanol and the toluene, the post-treatment unit comprises a powder treatment subunit and a plate-and-frame filter filled with anhydrous sodium sulfate, the plate-and-frame filter is connected with an outlet at the top of the styrene rectifying tower, the powder treatment subunit comprises a mixing component, a drying component and a roasting component which are sequentially connected, and a bottom outlet of the styrene rectifying tower and a filter residue discharge port of the triple filtration unit are connected with the mixing component.
Compared with the prior common wastewater treatment technology, the invention has the beneficial effects that:
1) the method has the advantages of reliable technology, obvious effect, low treatment cost, simple operation and easy realization of industrial application;
2) The technology of the invention greatly reduces the discharge amount of inorganic/organic matter, even zero discharge, and realizes a new environment-friendly wastewater treatment process;
3) After the technology of the invention is adopted to treat the methanol toluene styrene wastewater with the COD value up to 45000mg/L, the concentration of the activated sludge is more than 20mg/L, and the obtained separation solution has higher concentration and can be used as an industrial raw material after simple treatment, thereby further improving the economic benefit.
drawings
Fig. 1 shows a flow chart of a process for treating high-concentration wastewater from the production of styrene from methanol and toluene according to an exemplary embodiment of the present invention.
Fig. 2 is a block diagram illustrating the construction of a treatment apparatus for high concentration wastewater from the production of styrene from methanol and toluene according to an exemplary embodiment of the present invention.
Detailed Description
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
The high-concentration wastewater from the production of styrene by using methanol and toluene, which is treated by the invention, contains more organic matters such as methanol, toluene, ethylbenzene, styrene and the like, the treatment cost is higher if the wastewater is directly discharged to a sewage treatment plant, and material loss occurs because part of materials cannot be recovered.
Fig. 1 shows a flow chart of a process for treating high-concentration wastewater from the production of styrene from methanol and toluene according to an exemplary embodiment of the present invention.
As shown in fig. 1, the treatment process of high-concentration wastewater from the production of styrene from methanol and toluene according to an exemplary embodiment of the present invention includes the following steps.
Step A:
Adding a flocculating agent into the high-concentration wastewater generated in the production of styrene from methanol and toluene for flocculation treatment to obtain flocculated wastewater. Wherein, the COD value of the high-concentration wastewater generated in the production of styrene by methanol and toluene is more than 4500 mg/L.
In the step A, the flocculant can be one or more of aluminum sulfate, ferric sulfate, hydroxypropyl methylcellulose and polyacrylamide, and is preferably added in the form of solution, and the concentration of the flocculant solution is 0.1-0.2%. Wherein the volume ratio of the flocculant solution to the high-concentration wastewater generated in the production of styrene from methanol and toluene is 1: 400-1: 5000, the flocculation time is controlled to be 0.5-10 h, and the stirring speed is 10-250 r/min.
Through the flocculation treatment of this step, can condense the particulate matter in the waste water effectively and form the large granule, the follow-up filtering of being convenient for. The flocculation treatment can lead suspended particles in the sewage to be rapidly gathered and enlarged or form floccules, thereby accelerating the coagulation of the particles and finally achieving the purpose of solid-liquid separation.
And B:
And D, carrying out triple filtration on the flocculated wastewater obtained in the step A to obtain filter residue and filtrate.
The triple filtration adopts a three-section series filtration method, and comprises mechanical filtration, filter screen filtration and security filtration which are sequentially carried out. Wherein the filtration rate of the mechanical filtration is 1-20 m3H and preferably 5 to 12m3And h, the filtering precision of the filter screen filtering is 200-1000 meshes, preferably 600-800 meshes, the filtering precision of security filtering is 5-20 mu m, and the parameters are controlled to enable the concentration of the activated sludge to be about 20 mg/L.
The filtering speed of mechanical filtering is high, and filter residues with larger particles can be filtered firstly; the filter screen filters the filter residues with larger particles, and finally the filter residues with fine particles are filtered by the security filter. By adopting the three-section series-connection type filtering method, the defects of the traditional single filtering mode are greatly overcome, the filter residue and the organic matters can be separated out in a high-selectivity manner, most of reaction raw materials and products can be recycled, the problem that the subsequent treatment cost of filtrate is increased due to excessive filter residue is avoided, the treatment difficulty of waste water is reduced, the economic benefit maximization can be realized by recycling the raw materials and the products, the technical economy is improved, the organic matter concentration in the filter residue is greatly reduced, and the emission of organic volatile matters caused by filter residue treatment is reduced.
And C:
C, performing primary rectification separation on the filtrate obtained by filtering in the step B to obtain a high-concentration ethylbenzene solution and a high-concentration styrene solution; performing secondary rectification separation on the obtained high-concentration ethylbenzene solution to obtain a methanol-toluene mixed solution and a high-purity ethylbenzene solution; and refining and separating the obtained high-concentration styrene solution to obtain high-purity styrene and catalyst powder.
The primary rectification separation is carried out through a primary rectification tower, the operation temperature of the tower bottom is controlled to be 80-100 ℃, the operation pressure of the tower bottom is controlled to be 20-40 kPa, the operation temperature of the tower top is controlled to be 65-90 ℃, the operation pressure of the tower top is controlled to be 10-30 kPa, the reflux ratio of the tower top is controlled to be 5-12, high-concentration ethylbenzene solution is obtained from the tower top, and high-concentration styrene solution is obtained from the tower bottom.
And (3) separating the second-stage rectification separation by using a second-stage rectification tower, controlling the operation temperature to be 70-90 ℃, the operation pressure to be 90-150 kPa, controlling the reflux ratio at the top of the tower to be 1-10, obtaining a methanol-toluene mixed solution from the top of the tower and obtaining a high-concentration ethylbenzene solution from the bottom of the tower.
And (3) separating the refined and separated styrene by a styrene rectifying tower, controlling the operation temperature of the tower top to be 70-90 ℃, the operation pressure to be 4-20 kPa, controlling the operation temperature of the tower bottom to be 80-100 ℃ and the operation pressure to be 8-30 kPa, and obtaining high-purity styrene from the tower top and catalyst powder rich in tar from the tower bottom.
Because the materials such as methanol, toluene, ethylbenzene, styrene and the like with certain content in the high-concentration wastewater can be fully recovered and reused by rectification separation, the raw material recovery and the product recovery are achieved, and the technical economy of the process is improved. After the various products are separated, the products can be respectively post-treated to obtain the required recovered products.
Specifically, the obtained high-purity styrene is subjected to water absorption treatment through anhydrous sodium sulfate to obtain a high-purity styrene product, and the sodium sulfate after water absorption is recycled. And purifying the obtained methanol-toluene mixed solution and the high-purity ethylbenzene solution, and reusing the purified methanol-toluene mixed solution and the high-purity ethylbenzene solution as industrial raw materials. And C, mixing the catalyst powder obtained in the step C with the filter residue obtained in the step B, drying at 100-130 ℃ for 4-6 h, heating to 400-450 ℃, roasting for 2-4 h, and filling into a methanol-toluene side alkylation reactor for recycling.
The invention also provides a treatment device for the high-concentration wastewater generated in the production of styrene from methanol and toluene.
Fig. 2 is a block diagram illustrating the construction of a treatment apparatus for high concentration wastewater from the production of styrene from methanol and toluene according to an exemplary embodiment of the present invention.
As shown in fig. 2, the treatment apparatus for high concentration wastewater from methanol toluene production styrene according to an exemplary embodiment of the present invention includes a flocculation treatment unit, a triple filtration unit, a separation unit, and a post-treatment unit connected in series to achieve flocculation treatment, filtration treatment, rectification separation treatment, and post-treatment in series.
Wherein, the triple filtration unit comprises a mechanical filter, a filter screen filter and a security filter which are connected in sequence, and the separation unit comprises a first-stage rectifying tower, a second-stage rectifying tower and a styrene rectifying tower. Specifically, the top outlet of the first-stage rectifying tower is connected with the inlet of the second-stage rectifying tower, and the bottom outlet of the first-stage rectifying tower is connected with the styrene rectifying tower, so that the high-concentration ethylbenzene solution flowing out of the top of the first-stage rectifying tower enters the second-stage rectifying tower for second-stage rectifying separation, and the high-concentration styrene solution flowing out of the bottom of the first-stage rectifying tower enters the styrene rectifying tower for refining separation.
In addition, the post-treatment unit comprises a powder treatment subunit and a plate-and-frame filter filled with anhydrous sodium sulfate, wherein the powder treatment subunit is used for treating filter residues and catalyst powder, and the plate-and-frame filter is used for further removing water in the high-purity styrene.
wherein, the plate and frame filter is connected with the outlet of the top of the styrene rectifying tower, and the high-purity styrene obtained from the top of the styrene rectifying tower is removed from the excessive moisture by the plate and frame filter filled with anhydrous sodium sulfate. The powder processing subunit comprises a mixing component, a drying component and a roasting component which are sequentially connected, wherein the tower bottom outlet of the styrene rectifying tower and the filter residue discharge port of the triple filtering unit are connected with the mixing component, so that the catalyst powder obtained at the tower bottom of the styrene rectifying tower and the filter residue obtained in each filtering step are mixed in the mixing component, and after organic matters and moisture in the catalyst powder are removed through drying and roasting in sequence, the catalyst powder can be filled into a methanol-toluene side alkane reactor for recycling.
The separation unit used in the present invention may adopt structures, packing and internals which are superior in the prior art, and the present invention is not particularly limited thereto. The powder processing subunit of the invention can have the same structure as the equipment such as the filter residue recovery device in the prior art, but the invention improves the technical economy by further recycling the separated catalyst powder.
The process and the equipment of the invention can realize zero discharge on the premise of greatly reducing the terminal anhydrous discharge, thereby realizing double improvement on a methanol toluene alkylation production styrene production device and a wastewater treatment process, achieving the effect of sectional treatment, and realizing the best use of the recovered waste.
in order to make the technical means, inventive features, objectives and effects achieved by the present invention easily understandable, the present invention is further described in detail by examples and comparative examples below.
example 1:
Adding a certain amount of anionic polyacrylamide (with the molecular weight of 1000-1000 ten thousand) solution into high-concentration wastewater (COD is 4500mg/L) generated in the production of styrene from methanol and toluene for flocculation precipitation, wherein the mass fraction of the polyacrylamide solution is 0.1%, the adding ratio is 1:2000, the flocculation time is 4h, and the stirring speed is 200 r/min.
Filtering the wastewater after flocculation precipitation by a mechanical filter at a filtering speed of 5m3And h, removing and collecting filter residues, filtering the obtained filtrate in a filter screen filter with the mesh number of 500 meshes, removing and collecting the filter residues, then sending the filtrate obtained by filtering through the filter screen into a 5-20 mu m security filter for filtering, and sending the filtrate into the next stage, wherein the concentration of the activated sludge is 21.0 mg/L.
And (3) separating the filtrate obtained by the cartridge filter through a primary rectifying tower, controlling the temperature at the top of the primary rectifying tower to be 80 ℃, the operating pressure to be 25kPa, the reflux ratio to be 10, the temperature at the bottom of the primary rectifying tower to be 90 ℃, and the operating pressure to be 35kPa, then obtaining a high-concentration ethylbenzene solution from the top of the primary rectifying tower, and obtaining a high-concentration styrene solution (containing a very small amount of catalyst) from the bottom of the primary rectifying tower.
And (3) conveying the tower top solution of the primary rectifying tower to a secondary rectifying tower, separating by the secondary rectifying tower, controlling the operating temperature of the secondary rectifying tower at 80 ℃, controlling the operating pressure at 125kPa, and controlling the tower top reflux ratio at 8. High-concentration ethylbenzene solution (mass content is 98%) is obtained at the bottom of the second-stage rectifying tower, and can be sent to a downstream process or a storage tank after simple treatment; the high-concentration methanol-toluene mixed solution is obtained at the tower top, and can be sent to the inlet of a reactor for producing styrene from methanol-toluene as a raw material after being processed.
And (3) feeding the tower bottom solution of the primary rectifying tower to a styrene rectifying tower for separation and purification to obtain high-purity styrene, controlling the tower top temperature of the styrene rectifying tower at 75 ℃, the operating pressure at 12kPa, the tower bottom temperature at 85 ℃, the operating pressure at 25kPa, obtaining high-purity styrene (the mass content is 97%) at the tower top, and obtaining the catalyst powder rich in tar at the tower bottom.
The high-purity styrene is subjected to moisture removal by a plate and frame filter filled with anhydrous sodium sulfate to obtain a high-purity styrene product, the catalyst powder is mixed with the filter residue, dried for 4 hours at 130 ℃, roasted for 4 hours at 400 ℃, collected and then sent to a catalyst bed layer to be used as a catalyst for repeated use.
Example 2:
Adding a certain amount of aluminum sulfate solution into high-concentration wastewater (COD is 5000mg/L) produced in the production of styrene from methanol and toluene for flocculation precipitation, wherein the mass fraction of the aluminum sulfate solution is 0.1 percent, the adding ratio is 1:5000, the flocculation time is 10 hours, and the stirring speed is 250 revolutions per minute.
filtering the wastewater after flocculation precipitation by a mechanical filter at a filtering speed of 20m3Removing and collecting filter residues, filtering the obtained filtrate with a filter screen filter with the mesh number of 200 meshes, removing and collecting the filter residues, and filtering the filter screen to obtain the filtrateAnd (3) sending the filtrate into a 5-20 mu m security filter for filtering and sending into the next stage, wherein the concentration of the activated sludge is 20.2 mg/L.
And (2) separating the filtrate obtained by the cartridge filter through a primary rectifying tower, controlling the temperature at the top of the primary rectifying tower to be 90 ℃, the operating pressure to be 30kPa, the reflux ratio to be 5, the temperature at the bottom of the primary rectifying tower to be 100 ℃, and the operating pressure to be 40kPa, then obtaining a high-concentration ethylbenzene solution (with the mass content of 90%) from the top of the primary rectifying tower, and obtaining a high-concentration styrene solution (containing a very small amount of catalyst) from the top of the primary rectifying tower.
And (3) conveying the tower top solution of the primary rectifying tower to a secondary rectifying tower, separating by the secondary rectifying tower, controlling the operating temperature of the secondary rectifying tower at 90 ℃, controlling the operating pressure at 150kPa, and controlling the tower top reflux ratio at 10. High-concentration ethylbenzene solution (the mass content is 94%) is obtained at the bottom of the second-stage rectifying tower, and can be sent to a downstream process or a storage tank after simple treatment; the high-concentration methanol-toluene mixed solution is obtained at the tower top, and can be sent to the inlet of a reactor for producing styrene from methanol-toluene as a raw material after being processed.
And (3) feeding the tower bottom solution of the primary rectifying tower to a styrene rectifying tower for separation and purification to obtain a high-purity styrene solution, controlling the tower top temperature of the styrene rectifying tower at 70 ℃, the operating pressure at 4kPa, the tower bottom temperature at 80 ℃, the operating pressure at 8kPa, obtaining the high-purity styrene solution (the mass content is 93%) at the tower top, and obtaining the catalyst powder rich in tar at the tower bottom.
The high-purity styrene is subjected to moisture removal by a plate and frame filter filled with anhydrous sodium sulfate to obtain a high-purity styrene product, the catalyst powder is mixed with the filter residue, dried at 100 ℃ for 6 hours, roasted at 450 ℃ for 2 hours, collected and sent to a catalyst bed layer to be used as a catalyst for repeated use.
Example 3:
Adding a certain amount of ferric sulfate solution into high-concentration wastewater (COD is 4800mg/L) generated in the production of styrene from methanol and toluene for flocculation and precipitation, wherein the mass fraction of the ferric sulfate solution is 0.2%, the adding proportion is 1:400, the flocculation time is 0.5h, and the stirring speed is 10 r/min.
The wastewater after the flocculation precipitation passes through a machineFiltering with a mechanical filter at a filtering rate of 1m3And h, removing and collecting filter residues, filtering the obtained filtrate in a filter screen filter with the mesh number of 1000 meshes, removing and collecting the filter residues, then sending the filtrate obtained by filtering through the filter screen into a 5-20 mu m security filter for filtering, and sending the filtrate into the next stage, wherein the concentration of the activated sludge is 20.5 mg/L.
And (3) separating the filtrate obtained by the cartridge filter through a primary rectifying tower, controlling the temperature at the top of the primary rectifying tower to be 65 ℃, the operating pressure to be 10kPa, the reflux ratio to be 12, the temperature at the bottom of the primary rectifying tower to be 80 ℃, and the operating pressure to be 20kPa, then obtaining a high-concentration ethylbenzene solution from the top of the primary rectifying tower, and obtaining a high-concentration styrene solution (containing a very small amount of catalyst) from the bottom of the primary rectifying tower.
And (3) conveying the tower top solution of the primary rectifying tower to a secondary rectifying tower, separating by the secondary rectifying tower, controlling the operating temperature of the secondary rectifying tower at 70 ℃, controlling the operating pressure at 90kPa, and controlling the tower top reflux ratio at 1. High-concentration ethylbenzene solution (the mass content is 93%) is obtained at the bottom of the second-stage rectifying tower, and can be sent to a downstream process or a storage tank after simple treatment; the high-concentration methanol-toluene mixed solution is obtained at the tower top, and can be sent to the inlet of a reactor for producing styrene from methanol-toluene as a raw material after being processed.
And (3) feeding the tower bottom solution of the primary rectifying tower to a styrene rectifying tower for separation and purification to obtain a high-purity styrene solution, controlling the tower top temperature of the styrene rectifying tower at 90 ℃, the operating pressure at 20kPa, the tower bottom temperature at 100 ℃, the operating pressure at 30kPa, obtaining the high-purity styrene solution (the mass content is 93%) at the tower top, and obtaining the catalyst powder rich in tar at the tower bottom.
The high-purity styrene is subjected to moisture removal by a plate and frame filter filled with anhydrous sodium sulfate to obtain a high-purity styrene product, the catalyst powder is mixed with the filter residue, dried for 5 hours at 110 ℃, roasted for 3.5 hours at 430 ℃, collected and then sent to a catalyst bed layer to be used as a catalyst for repeated use.
Example 4:
Adding a certain amount of hydroxypropyl methyl cellulose and anionic polyacrylamide (with the molecular weight of 1000-1000 ten thousand) solution into high-concentration wastewater (COD is 4900mg/L) generated in the production of styrene from methanol and toluene for flocculation precipitation, wherein the mass fractions of polyacrylamide and anionic polyacrylamide in the solution are 0.03 percent and 0.07 percent respectively, the addition ratio is 1:4000, the flocculation time is 9 hours, and the stirring speed 210 is rotation/min.
filtering the wastewater after flocculation precipitation by a mechanical filter at a filtering speed of 10m3And h, removing and collecting filter residues, filtering the obtained filtrate in a filter screen filter with the mesh number of 800 meshes, removing and collecting the filter residues, then sending the filtrate obtained by filtering through the filter screen into a 5-20 mu m security filter for filtering, and sending the filtrate into the next stage, wherein the concentration of the activated sludge is 20.5 mg/L.
And (3) separating the filtrate obtained by the cartridge filter through a primary rectifying tower, controlling the temperature at the top of the primary rectifying tower to be 82 ℃, the operating pressure to be 15kPa, the reflux ratio to be 8, the temperature at the bottom of the primary rectifying tower to be 90 ℃, and the operating pressure to be 25kPa, then obtaining a high-concentration ethylbenzene solution from the top of the primary rectifying tower, and obtaining a high-concentration styrene solution (containing a very small amount of catalyst) from the bottom of the primary rectifying tower.
And (3) conveying the tower top solution of the primary rectifying tower to a secondary rectifying tower, separating by the secondary rectifying tower, controlling the operating temperature of the secondary rectifying tower at 79 ℃, controlling the operating pressure at 113kPa, and controlling the tower top reflux ratio at 6. High-concentration ethylbenzene solution (with the mass content of 99.5%) is obtained at the bottom of the second-stage rectifying tower, and can be sent to a downstream process or a storage tank after simple treatment; the high-concentration methanol-toluene mixed solution is obtained at the tower top, and can be sent to the inlet of a reactor for producing styrene from methanol-toluene as a raw material after being processed.
and (3) feeding the tower bottom solution of the primary rectifying tower to a styrene rectifying tower for separation and purification to obtain a high-purity styrene solution, controlling the temperature at the top of the styrene rectifying tower at 78 ℃, the operating pressure at the bottom of the styrene rectifying tower at 85 ℃, the operating pressure at the bottom of the styrene rectifying tower at 21kPa, obtaining the high-purity styrene solution (with the mass content of 99.4%) at the top of the tower, and obtaining the catalyst powder rich in tar at the bottom of the tower.
The high-purity styrene is subjected to moisture removal by a plate and frame filter filled with anhydrous sodium sulfate to obtain a high-purity styrene product, the catalyst powder is mixed with the filter residue, dried for 4 hours at 120 ℃, roasted for 2 hours at 440 ℃, collected and then sent to a catalyst bed layer to be used as a catalyst for repeated use.
Example 5:
adding a certain amount of hydroxypropyl methyl cellulose solution into high-concentration wastewater (COD is 4600mg/L) generated in the production of styrene from methanol and toluene for flocculation precipitation, wherein the mass fraction of the polyacrylamide solution is 0.1%, the adding ratio is 1:1500, the flocculation time is 7h, and the stirring speed is 150 r/min.
Filtering the wastewater after flocculation precipitation by a mechanical filter at a filtering speed of 10m3And h, removing and collecting filter residues, filtering the obtained filtrate in a filter screen filter with the mesh number of 600 meshes, removing and collecting the filter residues, then sending the filtrate obtained by filtering through the filter screen into a 5-20 mu m security filter for filtering, and sending the filtrate into the next stage, wherein the concentration of the activated sludge is 20.0 mg/L.
And (3) separating the filtrate obtained by the cartridge filter through a primary rectifying tower, controlling the temperature at the top of the primary rectifying tower to be 78 ℃, the operating pressure to be 12kPa, the reflux ratio to be 8, the temperature at the bottom of the primary rectifying tower to be 88 ℃, and the operating pressure to be 20kPa, then obtaining a high-concentration ethylbenzene solution from the top of the primary rectifying tower, and obtaining a high-concentration styrene solution (containing a very small amount of catalyst) from the bottom of the primary rectifying tower.
And (3) conveying the tower top solution of the primary rectifying tower to a secondary rectifying tower, separating by the secondary rectifying tower, controlling the operating temperature of the secondary rectifying tower at 76 ℃, controlling the operating pressure at 103kPa, and controlling the tower top reflux ratio at 5. High-concentration ethylbenzene solution (with the mass content of 98.5%) is obtained at the bottom of the second-stage rectifying tower, and can be sent to a downstream process or a storage tank after simple treatment; the high-concentration methanol-toluene mixed solution is obtained at the tower top, and can be sent to the inlet of a reactor for producing styrene from methanol-toluene as a raw material after being processed.
And (3) feeding the tower bottom solution of the primary rectifying tower to a styrene rectifying tower for separation and purification to obtain a high-purity styrene solution, controlling the tower top temperature of the styrene rectifying tower at 80 ℃, the operating pressure at 15kPa, the tower bottom temperature at 88 ℃, the operating pressure at 23kPa, obtaining the high-purity styrene solution (with the mass content of 98.4%) at the tower top, and obtaining the catalyst powder rich in tar at the tower bottom.
the high-purity styrene is subjected to moisture removal by a plate and frame filter filled with anhydrous sodium sulfate to obtain a high-purity styrene product, the catalyst powder is mixed with the filter residue, dried for 5 hours at 130 ℃, roasted for 3.5 hours at 440 ℃, collected and then sent to a catalyst bed layer to be used as a catalyst for repeated use.
in conclusion, aiming at the problems that the high-concentration wastewater from the preparation of styrene from methanol and toluene has high organic content and contains more expensive catalyst powder, the invention adopts the flow of flocculation precipitation, filtration, separation and post-treatment to recycle the components contained in the high-concentration wastewater. The invention not only reduces the discharge amount of organic pollutants, but also can reduce the treatment cost of wastewater through recycling, and even achieves the effect of profit. The method for treating the high-concentration wastewater generated in the production of styrene from methanol and toluene has the advantages of stable system operation, low treatment cost, good technical economy and easy realization of industrial application, and can greatly improve the technical economy and popularization possibility of the wastewater treatment process technology.
The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.

Claims (10)

1. A treatment process for high-concentration wastewater generated in the production of styrene from methanol and toluene is characterized by comprising the following steps:
A. Adding a flocculating agent into the high-concentration wastewater generated in the production of styrene from methanol and toluene for flocculation treatment to obtain flocculated wastewater, wherein the COD value of the high-concentration wastewater generated in the production of styrene from methanol and toluene is above 4500 mg/L;
B. Carrying out triple filtration on the flocculated wastewater to obtain filter residue and filtrate;
C. Performing primary rectification separation on the filtrate to obtain a high-concentration ethylbenzene solution and a high-concentration styrene solution; performing secondary rectification separation on the high-concentration ethylbenzene solution to obtain a methanol-toluene mixed solution and a high-purity ethylbenzene solution; and refining and separating the high-concentration styrene solution to obtain high-purity styrene and catalyst powder.
2. The treatment process for high-concentration wastewater generated in the production of styrene from methanol and toluene according to claim 1, wherein in the step A, the flocculant is one or more of aluminum sulfate, ferric sulfate, hydroxypropyl methylcellulose and polyacrylamide, the flocculant is added in the form of a solution, and the concentration of the flocculant solution is 0.1-0.2%; the volume ratio of the flocculant solution to the high-concentration wastewater generated in the production of styrene from methanol and toluene is 1: 400-1: 5000, the flocculation time is controlled to be 0.5-10 h, and the stirring speed is 10-250 r/min.
3. The treatment process for high-concentration wastewater generated in the production of styrene from methanol and toluene as claimed in claim 1, wherein in the step B, the triple filtration comprises mechanical filtration, filter screen filtration and security filtration which are sequentially carried out, and the filtration rate of the mechanical filtration is 1-20 m3H and preferably 5 to 12m3The filtering precision of the filter screen is 200-1000 meshes, preferably 600-800 meshes, and the filtering precision of security filtration is 5-20 mu m.
4. The treatment process for high-concentration wastewater generated in the production of styrene from methanol and toluene as claimed in claim 1, wherein in step C, the primary rectification separation is performed by a primary rectification tower, the tower bottom operating temperature is controlled to be 80-100 ℃, the tower bottom operating pressure is controlled to be 20-40 kPa, the tower top operating temperature is controlled to be 65-90 ℃, the tower top operating pressure is controlled to be 10-30 kPa, the tower top reflux ratio is controlled to be 5-12, and a high-concentration ethylbenzene solution is obtained from the tower top and a high-concentration styrene solution is obtained from the tower bottom.
5. the process for treating high-concentration wastewater from the production of styrene by using methanol and toluene as claimed in claim 1, wherein in step C, the secondary rectification separation is performed by using a secondary rectification tower, the operation temperature is controlled to be 70-90 ℃, the operation pressure is controlled to be 90-150 kPa, the reflux ratio at the top of the tower is controlled to be 1-10, the methanol and toluene mixed solution is obtained from the top of the tower, and the high-concentration ethylbenzene solution is obtained from the bottom of the tower.
6. the process for treating high-concentration wastewater from the production of styrene from methanol and toluene as claimed in claim 1, wherein in step C, the refining separation is performed by a styrene rectifying tower, the operation temperature at the top of the tower is controlled to be 70-90 ℃, the operation pressure is controlled to be 4-20 kPa, the operation temperature at the bottom of the tower is controlled to be 80-100 ℃, the operation pressure is controlled to be 8-30 kPa, high-purity styrene products are obtained from the top of the tower, and catalyst powder rich in tar is obtained from the bottom of the tower.
7. The process for treating high-concentration wastewater from styrene production with methanol and toluene as claimed in claim 1, wherein in step C, the high-purity styrene is subjected to water absorption treatment by anhydrous sodium sulfate to obtain a high-purity styrene product, and the sodium sulfate after water absorption is recycled; and purifying the methanol-toluene mixed solution and the high-purity ethylbenzene solution, and recycling the purified methanol-toluene mixed solution and the high-purity ethylbenzene solution as industrial raw materials.
8. The treatment process of high-concentration wastewater from styrene production with methanol and toluene as claimed in claim 1, wherein the catalyst powder obtained in step C is mixed with the filter residue obtained in step B, dried at 100-130 ℃ for 4-6 h, heated to 400-450 ℃ and calcined for 2-4 h, and then filled into a methanol and toluene side-chain alkylation reactor for recycling.
9. The utility model provides a treatment facility of methyl alcohol toluene production styrene high concentration waste water, a serial communication port, treatment facility is including flocculation processing unit, triple filter unit, separating element and the aftertreatment unit that links to each other in order, triple filter unit is including mechanical filter, filter screen filter and the safety filter ware that links to each other in order, separating element includes one-level rectifying column, second grade rectifying column and styrene rectifying column, the top of the tower export of one-level rectifying column links to each other with the entry of second grade rectifying column and the export at the bottom of the tower of one-level rectifying column links to each other with styrene rectifying column.
10. The equipment for treating high-concentration wastewater generated in the production of styrene from methanol and toluene according to claim 9, wherein the post-treatment unit comprises a powder treatment subunit and a plate-and-frame filter filled with anhydrous sodium sulfate, the plate-and-frame filter is connected with the outlet at the top of the styrene rectifying tower, the powder treatment subunit comprises a mixing component, a drying component and a roasting component which are sequentially connected, and the outlet at the bottom of the styrene rectifying tower and the residue discharge outlet of the triple filtration unit are connected with the mixing component.
CN201910846425.7A 2019-09-09 2019-09-09 Treatment process and equipment for high-concentration wastewater generated in production of styrene from methanol and toluene Pending CN110563539A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102964203A (en) * 2012-11-19 2013-03-13 同济大学 High-selectivity method for synthesizing styrene through methanol and toluene side chain alkylation
US20150158793A1 (en) * 2008-12-29 2015-06-11 Fina Technology, Inc. Method for Production of Styrene from Toluene and Methanol
CN109651052A (en) * 2019-01-28 2019-04-19 内江师范学院 The treatment process and processing system of methanol toluene production styrene high-concentration waste water

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150158793A1 (en) * 2008-12-29 2015-06-11 Fina Technology, Inc. Method for Production of Styrene from Toluene and Methanol
CN102964203A (en) * 2012-11-19 2013-03-13 同济大学 High-selectivity method for synthesizing styrene through methanol and toluene side chain alkylation
CN109651052A (en) * 2019-01-28 2019-04-19 内江师范学院 The treatment process and processing system of methanol toluene production styrene high-concentration waste water

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Application publication date: 20191213