CN107866222B - Ammonium sulfate-free process method in acrylonitrile reaction device - Google Patents

Ammonium sulfate-free process method in acrylonitrile reaction device Download PDF

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CN107866222B
CN107866222B CN201610851831.9A CN201610851831A CN107866222B CN 107866222 B CN107866222 B CN 107866222B CN 201610851831 A CN201610851831 A CN 201610851831A CN 107866222 B CN107866222 B CN 107866222B
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ammonia
absorption liquid
stripping
wet oxidation
cod
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CN107866222A (en
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郭宗英
吴粮华
姜家乐
陈航宁
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/56—Platinum group metals
    • B01J23/63—Platinum group metals with rare earths or actinides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
    • C01C1/00—Ammonia; Compounds thereof
    • C01C1/02—Preparation, purification or separation of ammonia
    • C01C1/12—Separation of ammonia from gases and vapours
    • 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
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/725—Treatment of water, waste water, or sewage by oxidation by catalytic oxidation
    • 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
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/727—Treatment of water, waste water, or sewage by oxidation using pure oxygen or oxygen rich gas
    • 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
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/74—Treatment of water, waste water, or sewage by oxidation with air
    • 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
    • C02F2101/38—Organic compounds containing nitrogen
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Abstract

Enabling a high-ammonia product gas flow (6) from the ammonia oxidation reactor to contact with a low-COD lean ammonium absorption liquid (17) in a quenching tower (1) to absorb unreacted ammonia in the high-ammonia product gas flow to obtain an ammonium-rich absorption liquid (8) and a low-ammonia product gas flow (7); stripping the ammonium-rich absorption liquid (8) in a stripping tower (2) by stripping tower stripping gas (9) to remove volatile organic components (10), separating and removing light components (11) floating on the upper layer and heavy components (12) sinking on the lower layer in a separation device (3), then heating and stripping in a stripping tower (4) by stripping tower stripping gas (13) to obtain a crude ammonia gas stream (15) and a high-COD lean ammonium absorption liquid (14), and carrying out wet oxidation reaction on the high-COD lean ammonium absorption liquid (14) and an oxidant (16) in a wet oxidation reactor (5) to obtain a low-COD lean ammonium absorption liquid (17) which is returned to a quenching tower (1) for absorbing unreacted ammonia; the crude ammonia stream (15) is rectified to obtain an anhydrous ammonia stream.

Description

Ammonium sulfate-free process method in acrylonitrile reaction device
Technical Field
The invention relates to a process method for removing ammonium sulfate in an acrylonitrile reaction device.
Background
Due to the characteristics of water (such as no toxicity, low price, wide sources and the like), the water is often used as a reaction solvent, a medium or a heat carrier in the chemical production process, and therefore, the water quality of a water body is inevitably damaged. With the vigorous development of the chemical industry, the water pollution is on the trend of rising year by year, wherein the water pollution caused by toxic organic matters is particularly serious. The pollutants have the characteristics of large discharge amount, wide pollution range, difficult biodegradation and the like, seriously threaten human life and simultaneously restrict the development of the chemical industry. Therefore, the research on how to treat industrial organic wastewater with high efficiency and energy saving is a problem to be solved urgently.
Industrial wastewater treatment methods have a particular range of applications. The traditional biological treatment technology, photocatalysis and wet peroxide oxidation are only suitable for treating low-concentration and non-biotoxic organic wastewater. Although the incineration method can treat high-concentration organic wastewater, a large amount of fuel oil is consumed for incineration, and the energy consumption is high; at the same time, incineration may generate, for example, NOx、COxAnd harmful gases such as dioxin cause secondary pollution to the environment. Wet oxidation was developed in the last 50 th century as a method for treating toxic, harmful, high-concentration organic wastewater. The method is to oxidize organic pollutants into CO in liquid phase by taking air or pure oxygen as an oxidant under the conditions of high temperature and high pressure2And inorganic substances such as water and the like or small molecular organic substances. The method has the advantages of wide application range, high treatment efficiency, high oxidation rate, small occupied area of equipment and the like. The catalytic wet oxidation technology is to add a high-efficiency and stable catalyst designed for the composition of wastewater in the traditional wet oxidation process, thereby greatly improving the oxidation efficiency, shortening the reaction residence time, reducing the temperature and pressure required by the reaction and reducing the production cost.
The catalytic wet oxidation technology is classified into homogeneous and heterogeneous catalytic wet oxidation according to the properties of the catalyst. Early studies focused primarily on homogeneous catalysts, but this process was phased out because of the secondary pollution caused by the catalyst dissolving in the waste, requiring subsequent treatment. In recent years, heterogeneous catalysts have become a research focus, and mainly comprise two main types of noble metals and metal oxides, wherein noble metal supported catalysts have high catalytic activity and stability, and at present, most of such catalysts are TiO2、ZrO2、CeO2Or a composite oxide thereof as a carrier, and Ru, Rh, Pd, Ir, Pt, Au being supported on the carrier.
The following patents are published for noble metal catalytic wet oxidation technology:
CN1084496A discloses a wet oxidation purification catalyst for industrial sewage containing high concentration organic matter and ammonia, which is prepared by loading noble metal component (one of Ru, Rh, Pd, Ir and Pt) and rare earth element on TiO2The preparation method adopts the preparation technology of co-impregnation or sub-impregnation of double active components. CN1121322A discloses a catalyst for wastewater treatment, a method for producing the same, and a method for wastewater treatment using the same, wherein the catalyst contains an oxide and/or composite oxide of manganese and an oxide and/or composite oxide of at least one metal selected from the group consisting of iron, titanium, and zirconium, and optionally a noble metal.
The activity and stability of the catalyst in the above patents are not ideal when the catalyst is used for treating acrylonitrile ammonium sulfate-free process wastewater.
Disclosure of Invention
The invention aims to solve the technical problems of low initial activity and poor stability of a heterogeneous catalytic wet oxidation reaction catalyst adopted in a process for recovering unreacted ammonia by an ammonium sulfate-free process in an acrylonitrile reaction device in the prior art, and provides a method for recovering the unreacted ammonia by the ammonium sulfate-free process in the acrylonitrile reaction device. The wet oxidation catalyst used in the method for heterogeneous catalysis wet oxidation reaction treatment of acrylonitrile ammonium sulfate-free process wastewater has the advantages of high initial activity and high stability.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for recovering unreacted ammonia by an ammonium sulfate-free process in an acrylonitrile reaction device comprises the following steps:
enabling a high-ammonia product gas flow (6) from the ammonia oxidation reactor to contact with a low-COD lean ammonium absorption liquid (17) in a quenching tower (1) to absorb unreacted ammonia in the high-ammonia product gas flow to obtain an ammonium-rich absorption liquid (8) and a low-ammonia product gas flow (7); stripping the ammonium-rich absorption liquid (8) in a stripping tower (2) by stripping tower stripping gas (9) to remove volatile organic components (10), separating and removing light components (11) floating on the upper layer and heavy components (12) sinking on the lower layer in a separation device (3), then heating and stripping in a stripping tower (4) by stripping tower stripping gas (13) to obtain a crude ammonia gas stream (15) and a high-COD lean ammonium absorption liquid (14), carrying out wet oxidation reaction on the high-COD lean ammonium absorption liquid (14) and an oxidant (16) in a wet oxidation reactor (5) filled with a wet oxidation catalyst to obtain a low-COD lean ammonium absorption liquid (17), and returning the low-COD lean ammonium absorption liquid (17) to the quenching tower (1) for absorbing unreacted ammonia; the crude ammonia stream (15) is rectified to obtain an anhydrous ammonia stream.
In the above technical solution, the lean ammonium absorption liquid contains at least one absorbent preferably selected from phosphoric acid or ammonium dihydrogen phosphate.
In the above technical solution, the oxidizing agent is preferably a gas containing oxygen molecules.
In the above technical solution, the oxidant is preferably pure oxygen, air or oxygen-enriched air.
In the technical scheme, the wet reaction temperature is preferably 220-300 ℃.
In the technical scheme, the wet reaction pressure is preferably 5.0-12.0 MPa.
In the technical scheme, the volume ratio of the oxygen to the lean ammonium absorption liquid is preferably 50-400.
In the technical scheme, the residence time of the lean ammonium absorption liquid in the wet oxidation reactor is preferably 10-90 minutes.
In the above technical solution, the COD of the lean ammonium absorption liquid is not particularly limited, for example, but not limited to, 5000 to 100000 mg/L.
In the technical scheme, stripping gas (9) of the stripping tower and/or stripping gas (13) of the desorption tower are gases inert to stripping substances.
In the above technical scheme, the gas inert to the stripping material is at least one of steam, air and nitrogen.
In the technical scheme, the high COD lean ammonium absorption liquid (14) takes water as a solvent.
In the above technical scheme, the temperature of the desorption tower is 150-.
In the above embodiment, the heavy component (12) is preferably a high polymer and/or an ammoxidation catalyst powder.
In the above technical solution, the wet oxidation catalyst preferably includes a carrier, and an active component and an auxiliary agent loaded on the carrier, wherein the carrier contains at least one of activated carbon and titanium dioxide, the active component is selected from at least one of Ru, Pd, Pt and Rh, and the auxiliary agent is selected from at least one of La, Ce and Nd.
In the above technical scheme, the carrier preferably contains both activated carbon and titanium dioxide, and at this time, the activated carbon and titanium dioxide have a synergistic effect on improving the initial activity and stability of the catalyst. By way of non-limiting example, the vector may have the structural form:
(1) the composite carrier is obtained after the active carbon and the titanium dioxide are simply and physically mixed and molded;
(2) the composite carrier takes active carbon as a core and titanium dioxide as a shell;
(3) the composite carrier takes a titanium dioxide active carbon mixture as a core and a titanium dioxide shell.
The composite carrier which takes the titanium dioxide active carbon mixture as the core and takes the titanium dioxide as the shell has the best effect in terms of improving the initial activity and the stability of the catalyst, then takes the active carbon as the core and takes the titanium dioxide as the shell, and then takes the active carbon and the titanium dioxide as the composite carrier obtained after simple physical mixing and molding.
In the above technical solution, in the case of the composite carrier with a titanium dioxide activated carbon mixture as a core and a titanium dioxide as a shell, the specific ratio of the core to the shell is not particularly limited, for example, but not limited to, 40 to 96% by weight of the core and 4 to 60% by weight of the shell, and the ratio of the titanium dioxide to the activated carbon in the core is also not particularly limited, for example, but not limited to, 30 to 95% by weight of the titanium dioxide and 5 to 70% by weight of the activated carbon.
In the above technical scheme, the content of the active component is preferably 0.01 to 2.5% by weight, and more preferably 0.1 to 1.5% by weight.
In the above technical scheme, the content of the auxiliary agent component is preferably 0.01 to 10.0%, and more preferably 0.1 to 5.0% by weight.
In the above technical solution, the preparation method of the wet oxidation catalyst comprises the following steps:
(1) mixing the compound solution of the active component and the auxiliary component with the carrier to obtain a catalyst precursor;
(2) reducing the combined active components in the catalyst precursor into simple substances by using a reducing agent.
In the above technical scheme, the specific method for reduction in step (2) is not particularly limited as long as the combined active component can be reduced to a simple substance. For example, the precursor may be reduced in the gas phase with a gaseous reducing agent, or may be reduced in the liquid phase with a solution of a reducing agent or a liquid phase reducing agent. Gaseous reducing agents commonly used may include hydrogen gas, such as hydrogen gas, hydrogen-nitrogen mixtures, and the like. The reducing agent for liquid phase reduction may be hydrazine hydrate, formic acid or sodium formate, etc.
In the above technical scheme, the compound of the active component in step (1) is not particularly limited, such as but not limited to ruthenium trichloride, palladium chloride, chloropalladic acid, chloroplatinic acid, rhodium chloride, etc.
In the above technical solution, the compound of the auxiliary component in step (1) is not particularly limited, and examples of the compound include, but are not limited to, lanthanum nitrate, lanthanum chloride, lanthanum oxalate, lanthanum sulfate, cerium chloride, cerium nitrate, cerium sulfate, neodymium nitrate, neodymium sulfate, and neodymium chloride.
In the technical scheme, when the gas containing hydrogen is used as the gaseous reducing agent for gas phase reduction in the reduction step (2), the catalyst precursor is preferably dried and roasted at the roasting temperature of preferably 400-600 ℃ for preferably 2-4.5 hours.
In the above technical scheme, when hydrogen is used for reduction in the step (2), the reduction temperature is preferably 300-650 ℃, and more preferably 350-600 ℃.
In the above technical scheme, the reduction time is preferably 1 to 5 hours, and more preferably 2.5 to 4.5 hours.
In the above technical scheme, when the composite carrier takes the titanium dioxide activated carbon mixture as the core and the titanium dioxide as the shell, the composite carrier is preferably prepared by a method comprising the following steps:
1) coprecipitating water turbid liquid containing titanium salt and active carbon and ammonia water to generate a gel substance, and filtering, washing, drying and roasting to obtain the material 1;
2) forming the material 1 to obtain a core of the composite carrier;
3) spraying titanium dioxide sol on the surface of the core in the step 2), and roasting to obtain the composite carrier.
In the above technical scheme, the titanium-containing salt in step 1) may be, but is not limited to, Ti (SO)4)2，TiOSO4，TiCl4And the like.
In the above technical scheme, the addition amount and concentration of the ammonia water in step 1) are not particularly limited, as long as the aqueous turbid solution containing titanium salt and activated carbon is co-precipitated to generate a gel substance, and for this purpose, a person skilled in the art can reasonably select the concentration and the amount of the ammonia water, and all the ammonia water can achieve comparable technical effects of the invention. By way of non-limiting example, the amount of ammonia added is such that the pH of the aqueous suspension containing the titanium salt and the activated carbon is 8.0 to 11.0, in the same ratio in the embodiment of the present invention, and the pH is adjusted to 9.8 by ammonia in all cases where a gel is formed by coprecipitation.
In the technical scheme, the roasting temperature in the step 1) is preferably 150-400 ℃, and further preferably 200-350 ℃; the roasting time is preferably 0.5-4 hours, and further preferably 1-3 hours; the firing atmosphere is preferably an atmosphere inert to the activated carbon, such as, but not limited to, nitrogen, argon, and the like.
In the above technical solution, the forming method of step 2) is not particularly limited, and those known to those skilled in the art, such as but not limited to ball forming, press forming, extrusion forming, etc., can be used. By way of non-limiting example, the extrusion molding process may be carried out using a process comprising the steps of:
in the technical scheme, the roasting temperature after spraying in the step 3) is preferably 400-950 ℃, and the roasting time is preferably 0.5-8 hours.
In the above technical scheme, the forming aid may be selected from an organic template agent or an extrusion aid.
By way of non-limiting example, in the above technical solution, the forming aid is at least one selected from ethylenediamine, n-butylamine, pyrrolidine, 1000 to 5000 parts of polyethylene glycol, oxalic acid, citric acid, tartaric acid, and sesbania powder.
It is known to those skilled in the art that wet oxidation catalysts are particularly effective on certain process-specific wastewaters, and have very high specificity. In the technical scheme, the wet oxidation catalyst is particularly suitable for being applied to wet oxidation treatment of organic wastewater of a non-ammonium sulfate process in an acrylonitrile production process.
By adopting the technical scheme of the invention, the industrial wastewater and the oxygen are mixed and then pass through the wet oxidation reactor filled with the catalyst, so that the COD removal rate at the initial stage of the reaction reaches more than 90 percent, the stability of the catalyst is also improved, and a better technical effect is obtained.
The invention is further illustrated by the following description of the figures and examples, which however do not in any way limit the scope of the invention.
Drawings
FIG. 1 is a process flow diagram of the application of the wet oxidation catalyst of the present invention in the wet oxidation treatment of organic wastewater of an ammonium sulfate-free process in the production of acrylonitrile.
1 is a quench tower; 2 is a stripping tower; 3 is a separation device; 4 is a resolving tower; 5 is a wet oxidation reactor; 6 is high ammonia product gas flow; 7 is a low ammonia product gas stream; 8 is rich ammonium absorption liquid; 9 is stripping gas of a stripping tower; 10 is a volatile organic component; 11 is a light component; 12 is a heavy component; 13 is stripping gas of the desorption tower; 14 is high COD lean ammonium absorption liquid; 15 is a crude ammonia stream; 16 is an oxygen-containing gas; and 17, obtaining low COD lean ammonium absorption liquid after wet oxidation reaction.
The wet oxidation catalyst absorbs unreacted ammonia in the high ammonia product gas flow 6 from the ammonia oxidation reactor in a quenching tower 1 in contact with low COD lean ammonium absorption liquid 17 to obtain rich ammonium absorption liquid 8 and low ammonia product gas flow 7; stripping the ammonium-rich absorption liquid 8 in a stripping tower 2 by stripping tower stripping gas 9 to remove volatile organic components 10, separating and removing light components 11 floating on the upper layer and heavy components 12 sinking on the lower layer in a separating device 3, then heating and stripping the stripping gas 13 in a resolving tower 4 by a resolving tower to obtain a crude ammonia gas stream 15 and a high-COD lean ammonium absorption liquid 14, and carrying out wet oxidation reaction on the high-COD lean ammonium absorption liquid 14 and oxygen-containing gas 16 in a wet oxidation reactor 5 filled with a wet oxidation catalyst to obtain a low-COD lean ammonium absorption liquid 17 which is returned to a quenching tower 1 for absorbing unreacted ammonia; the crude ammonia stream 15 is rectified to produce an anhydrous ammonia stream (not shown).
Detailed Description
The waste water used in the following examples and comparative examples was acrylonitrile ammonium sulfate-free process waste water having a COD value of 30000mg/l, and the reactor was a fixed bed reactor having an inner diameter of 14 mm and a reactor length of 600 mm. The catalyst evaluates the initial activity of the COD removal rate measured when continuously operating for 24 hours, and calculates the activity reduction rate through the change of the activity before and after the COD removal rate measured when continuously operating for 300 hours as the final activity, and the formula is as follows:
activity reduction rate,% (initial activity-final activity)/initial activity ] × 100%
The activity reduction rate was used as an index for evaluating the stability of the catalyst, and a lower value indicates a more stable catalyst performance, and vice versa.
[ example 1 ]
Preparing a catalyst:
step 1)
Preparing 0.3mol/l TiOSO4Adding 12g of activated carbon powder into 2000ml of aqueous solution, dripping 0.6mol/l of ammonia water into the turbid solution for coprecipitation to generate a gel substance, filtering, washing, drying, and roasting for 2 hours at 300 ℃ in a nitrogen atmosphere to obtain composite carrier core powder;
step 2)
Mixing 45g of composite carrier core powder, 0.1g of n-butylamine and 0.1g of oxalic acid, and kneading, extruding, pelleting and drying to obtain the core of the composite carrier; spraying 50g of sol with the titanium dioxide content of 10 percent on the core of the composite carrier, drying, and roasting at 850 ℃ for 4 hours to prepare the composite carrier;
step 3)
50g of the composite carrier was immersed in a cerium nitrate solution containing 1.30g of Ce. Dipping for 6h at room temperature, drying, and roasting for 2.5h at 350 ℃ to obtain a catalyst precursor;
step 4)
The catalyst precursor was immersed in RuCl containing 0.50g Ru3In solution. Dipping for 6h at room temperature, drying, roasting for 2.5h at 480 ℃, and then reducing for 3h at 400 ℃ by using hydrogen to obtain a catalyst finished product;
evaluation of catalyst:
and (2) loading the prepared catalyst into a wet oxidation reactor, mixing the wastewater with oxygen, and then carrying out catalytic wet oxidation reaction, wherein the retention time of the wastewater in the effective section of the reactor is 40min, the reaction temperature is 280 ℃, the reaction pressure is 9MPa, and the volume ratio of the oxygen to the wastewater is 100.
[ example 2 ]
Preparing a catalyst:
step 1)
Preparing 0.3mol/l TiOSO4Adding 0.6mol/l ammonia water into 2000ml of aqueous solution, dropping the ammonia water into the turbid solution, coprecipitating to generate a gel substance, filtering, washing, drying, and roasting for 2 hours at 300 ℃ in a nitrogen atmosphere to obtain titanium dioxide powder;
step 2)
Mixing 41g of titanium dioxide powder, 9g of activated carbon powder, 0.1g of n-butylamine and 0.1g of oxalic acid, kneading, extruding, pelleting and drying, and roasting at 850 ℃ for 4 hours to prepare a composite carrier;
step 3)
50g of the composite carrier was immersed in a cerium nitrate solution containing 1.30g of Ce. Dipping for 6h at room temperature, drying, and roasting for 2.5h at 350 ℃ to obtain a catalyst precursor;
step 4)
The catalyst precursor was immersed in RuCl containing 0.50g Ru3In solution. Dipping for 6h at room temperature, drying, roasting for 2.5h at 480 ℃, and then reducing for 3h at 400 ℃ by using hydrogen to obtain a catalyst finished product;
evaluation of catalyst:
and (2) loading the prepared catalyst into a wet oxidation reactor, mixing the wastewater with oxygen, and then carrying out catalytic wet oxidation reaction, wherein the retention time of the wastewater in the effective section of the reactor is 40min, the reaction temperature is 280 ℃, the reaction pressure is 9MPa, and the volume ratio of the oxygen to the wastewater is 100.
[ example 3 ]
Step 1)
Mixing 9g of activated carbon powder, 0.02g of n-butylamine and 0.02g of oxalic acid, kneading, extruding, pelleting and drying, and roasting for 2 hours at 300 ℃ in a nitrogen atmosphere to prepare a core of the composite carrier;
step 2)
Spraying 410g of sol with the titanium dioxide content of 10% on 9g of composite carrier cores for multiple times, drying, and roasting at 850 ℃ for 4 hours to prepare a composite carrier;
step 3)
50g of the composite carrier was immersed in a cerium nitrate solution containing 1.30g of Ce. Dipping for 6h at room temperature, drying, and roasting for 2.5h at 350 ℃ to obtain a catalyst precursor;
step 4)
The catalyst precursor was immersed in RuCl containing 0.50g Ru3In solution. Dipping for 6h at room temperature, drying, roasting for 2.5h at 480 ℃, and then reducing for 3h at 400 ℃ by using hydrogen to obtain a catalyst finished product;
evaluation of catalyst:
and (2) loading the prepared catalyst into a wet oxidation reactor, mixing the wastewater with oxygen, and then carrying out catalytic wet oxidation reaction, wherein the retention time of the wastewater in the effective section of the reactor is 40min, the reaction temperature is 280 ℃, the reaction pressure is 9MPa, and the volume ratio of the oxygen to the wastewater is 100.
Comparative example 1
Preparing a catalyst:
step 1)
Preparing 0.3mol/l TiOSO4Adding 0.6mol/l ammonia water into 2000ml of the aqueous solution, dropping the ammonia water into the turbid solution, coprecipitating to generate a gel substance, and filtering, washing and drying to obtain titanium dioxide powder;
step 2)
Mixing 50g of titanium dioxide powder, 0.1g of n-butylamine and 0.1g of oxalic acid, kneading, extruding, pelleting and drying, and roasting at 850 ℃ for 4 hours to prepare a carrier;
step 3)
50g of the composite carrier was immersed in a cerium nitrate solution containing 1.30g of Ce. Dipping for 6h at room temperature, drying, and roasting for 2.5h at 350 ℃ to obtain a catalyst precursor;
step 4)
The catalyst precursor was immersed in RuCl containing 0.50g Ru3In solution. At room temperatureDipping for 6h, drying, roasting for 2.5h at 480 ℃, and then reducing for 3h at 400 ℃ by using hydrogen to obtain a catalyst finished product;
evaluation of catalyst:
and (2) loading the prepared catalyst into a wet oxidation reactor, mixing the wastewater with oxygen, and then carrying out catalytic wet oxidation reaction, wherein the retention time of the wastewater in the effective section of the reactor is 40min, the reaction temperature is 280 ℃, the reaction pressure is 9MPa, and the volume ratio of the oxygen to the wastewater is 100.
[ COMPARATIVE EXAMPLE 2 ]
Preparing a catalyst:
step 1)
Mixing 50g of activated carbon powder, 0.1g of n-butylamine and 0.1g of oxalic acid, kneading, extruding, pelleting and drying, and roasting for 2 hours at 300 ℃ in a nitrogen atmosphere to obtain an activated carbon carrier;
step 2)
50g of the activated carbon support was immersed in a cerium nitrate solution containing 1.30g of Ce. Dipping for 6h at room temperature, drying, and roasting for 2.5h at 350 ℃ to obtain a catalyst precursor;
step 3)
The catalyst precursor was immersed in RuCl containing 0.50g Ru3In solution. Dipping for 6h at room temperature, drying, roasting for 2.5h at 480 ℃, and then reducing for 3h at 400 ℃ by using hydrogen to obtain a catalyst finished product;
evaluation of catalyst:
and (2) loading the prepared catalyst into a wet oxidation reactor, mixing the wastewater with oxygen, and then carrying out catalytic wet oxidation reaction, wherein the retention time of the wastewater in the effective section of the reactor is 40min, the reaction temperature is 280 ℃, the reaction pressure is 9MPa, and the volume ratio of the oxygen to the wastewater is 100.
[ example 4 ]
Preparing a catalyst:
step 1)
Preparing 0.3mol/l TiOSO4Adding 12g of activated carbon powder into 2000ml of aqueous solution, dripping 0.6mol/l of ammonia water into the turbid solution for coprecipitation to generate a gel substance, filtering, washing, drying, and roasting at 150 ℃ for 4 hours in a nitrogen atmosphere to obtain the composite carrierCore powder;
step 2)
Mixing 40g of composite carrier core powder, 0.1g of ethylenediamine and 0.1g of oxalic acid, and kneading, extruding, pelleting and drying to obtain the core of the composite carrier; spraying 100g of sol with the titanium dioxide content of 10 percent on the core of the composite carrier, drying, and roasting at 400 ℃ for 3 hours to prepare the composite carrier;
step 3)
50g of the composite carrier was immersed in a lanthanum nitrate solution containing 0.78g of La. Dipping for 6h at room temperature, drying, and roasting for 2.5h at 300 ℃ to obtain a catalyst precursor;
step 4)
Catalyst precursor was impregnated with H containing 0.25g of Pt2PtCl6In solution. Dipping for 6h at room temperature, drying, roasting for 2h 2.5h at 400 ℃ and 480 ℃, and then reducing for 2h by hydrogen at 300 ℃ and 400 ℃ to obtain a catalyst finished product;
evaluation of catalyst:
and (2) loading the prepared catalyst into a wet oxidation reactor, mixing the wastewater with oxygen, and then carrying out catalytic wet oxidation reaction, wherein the retention time of the wastewater in the effective section of the reactor is 40min, the reaction temperature is 280 ℃, the reaction pressure is 9MPa, and the volume ratio of the oxygen to the wastewater is 100.
[ example 5 ]
Preparing a catalyst:
step 1)
Preparing 0.3mol/l TiOSO4Adding 12g of activated carbon powder into 2000ml of aqueous solution, dripping 0.6mol/l of ammonia water into the turbid solution for coprecipitation to generate a gel substance, filtering, washing, drying, and roasting at 400 ℃ for 0.5 hour in a nitrogen atmosphere to obtain composite carrier core powder;
step 2)
Mixing 35g of composite carrier core powder, 0.1g of n-butylamine and 0.1g of sesbania powder, and kneading, extruding, pelleting and drying to obtain the core of the composite carrier; spraying 150g of sol with the titanium dioxide content of 10 percent on the core of the composite carrier, drying, and roasting at 950 ℃ for 0.5 hour to prepare the composite carrier;
step 3)
50g of the composite carrier was immersed in a lanthanum nitrate solution containing 1.90g of La. Dipping for 6h at room temperature, drying, and roasting for 2.5h at 350 ℃ to obtain a catalyst precursor;
step 4)
The catalyst precursor was immersed in PdCl containing 0.61g Pd2In solution. Dipping for 6h at room temperature, drying, roasting for 4h at 600 ℃, and then reducing for 2h at 650 ℃ by using hydrogen to obtain a finished catalyst;
evaluation of catalyst:
and (2) loading the prepared catalyst into a wet oxidation reactor, mixing the wastewater with oxygen, and then carrying out catalytic wet oxidation reaction, wherein the retention time of the wastewater in the effective section of the reactor is 60min, the reaction temperature is 280 ℃, the reaction pressure is 9MPa, and the volume ratio of the oxygen to the wastewater is 150.
[ example 6 ]
Preparing a catalyst:
step 1)
Preparing 0.3mol/l TiOSO4Adding 24g of activated carbon powder into 1500ml of aqueous solution, dripping 0.6mol/l of ammonia water into the turbid solution for coprecipitation to generate a gel substance, filtering, washing, drying, and roasting for 3 hours at 250 ℃ in a nitrogen atmosphere to obtain composite carrier core powder;
step 2)
Mixing 45g of composite carrier core powder, 0.1g of pyrrolidine and 0.1g of sesbania powder, and kneading, extruding, pelleting and drying to obtain the core of the composite carrier; spraying 50g of sol with the titanium dioxide content of 10 percent on the core of the composite carrier, drying, and roasting at 750 ℃ for 6 hours to prepare the composite carrier;
step 3)
50g of the composite carrier was immersed in a neodymium nitrate solution containing 1.10g of Nd. Dipping for 6h at room temperature, drying, and roasting for 2.5h at 350 ℃ to obtain a catalyst precursor;
step 4)
Catalyst precursor was impregnated with H containing 0.40g of Pt2PtCl6In solution. Soaking at room temperature for 6h, drying, calcining at 500 deg.C for 4h, and reducing with hydrogen at 500 deg.C for 4 hr to obtainTo obtain a catalyst finished product;
evaluation of catalyst:
and (2) loading the prepared catalyst into a wet oxidation reactor, mixing the wastewater with oxygen, and then carrying out catalytic wet oxidation reaction, wherein the retention time of the wastewater in the effective section of the reactor is 60min, the reaction temperature is 220 ℃, the reaction pressure is 6MPa, and the volume ratio of the oxygen to the wastewater is 150.
[ example 7 ]
Preparing a catalyst:
step 1)
Preparing 0.3mol/l TiOSO41250ml of aqueous solution is added with 30g of activated carbon powder, 0.6mol/l of ammonia water is dropped into the turbid solution for coprecipitation to generate gel substances, and the gel substances are filtered, washed and dried and are roasted for 3 hours at the temperature of 250 ℃ in nitrogen atmosphere to prepare composite carrier nuclear powder;
step 2)
Mixing 45g of composite carrier core powder, 0.1g of polyethylene glycol 2000 and 0.1g of oxalic acid, and kneading, extruding, pelleting and drying to obtain the core of the composite carrier; spraying 50g of sol with the titanium dioxide content of 10 percent on the core of the composite carrier, drying, and roasting at 800 ℃ for 5 hours to prepare the composite carrier;
step 3)
50g of the composite carrier was immersed in a cerium nitrate solution containing 2.0g of Ce. Dipping for 6h at room temperature, drying, and roasting for 2.5h at 350 ℃ to obtain a catalyst precursor;
step 4)
The catalyst precursor was immersed in RuCl containing 0.60g Ru3In solution. Dipping for 6h at room temperature, drying, roasting for 3h at 450 ℃, and then reducing for 2h at 600 ℃ by using hydrogen to obtain a catalyst finished product;
evaluation of catalyst:
and (2) loading the prepared catalyst into a wet oxidation reactor, mixing the wastewater with oxygen, and then carrying out catalytic wet oxidation reaction, wherein the retention time of the wastewater in the effective section of the reactor is 80min, the reaction temperature is 280 ℃, the reaction pressure is 9MPa, and the volume ratio of the oxygen to the wastewater is 100.
[ example 8 ]
Preparing a catalyst:
step 1)
Preparing 0.3mol/l TiOSO41375ml of aqueous solution, adding 27g of activated carbon powder, dripping 0.6mol/l of ammonia water into the turbid solution for coprecipitation to generate a gel substance, filtering, washing, drying, and roasting for 4 hours at 200 ℃ in a nitrogen atmosphere to prepare composite carrier core powder;
step 2)
Mixing 45g of composite carrier core powder, 0.1g of ethylenediamine and 0.1g of citric acid, kneading, extruding, pelleting and drying to obtain the core of the composite carrier; spraying 50g of sol with the titanium dioxide content of 10 percent on the core of the composite carrier, drying, and roasting at 850 ℃ for 5 hours to prepare the composite carrier;
step 3)
50g of the composite carrier was immersed in a cerium nitrate solution containing 2.50g of Ce. Dipping for 6h at room temperature, drying, and roasting for 2.5h at 350 ℃ to obtain a catalyst precursor;
step 4)
The catalyst precursor was impregnated in RhCl containing 0.90g of Rh3In solution. Dipping for 6h at room temperature, drying, roasting for 2.5h at 450 ℃, and then reducing for 3h at 400 ℃ by using hydrogen to obtain a catalyst finished product;
evaluation of catalyst:
and (2) loading the prepared catalyst into a wet oxidation reactor, mixing the wastewater with oxygen, and then carrying out catalytic wet oxidation reaction, wherein the retention time of the wastewater in the effective section of the reactor is 40min, the reaction temperature is 300 ℃, the reaction pressure is 10MPa, and the volume ratio of the oxygen to the wastewater is 200.
[ example 9 ]
Preparing a catalyst:
step 1)
Preparing 0.3mol/l TiOSO4Adding 15g of activated carbon powder into 1875ml of aqueous solution, dripping 0.6mol/l of ammonia water into the turbid solution for coprecipitation to generate a gel substance, filtering, washing, drying, and roasting at 250 ℃ for 4 hours in a nitrogen atmosphere to obtain composite carrier core powder;
step 2)
Mixing 45g of composite carrier core powder, 0.1g of n-butylamine and 0.1g of oxalic acid, and kneading, extruding, pelleting and drying to obtain the core of the composite carrier; spraying 50g of sol with the titanium dioxide content of 10 percent on the core of the composite carrier, drying, and roasting at 750 ℃ for 7 hours to prepare the composite carrier;
step 3)
50g of the composite carrier was immersed in a lanthanum nitrate solution containing 1.50g of La. Dipping for 6h at room temperature, drying, and roasting for 2.5h at 400 ℃ to obtain a catalyst precursor;
step 4)
The catalyst precursor was impregnated with RuCl containing 0.71g Ru3In solution. Dipping for 6h at room temperature, drying, roasting for 2.5h at 550 ℃, and then reducing for 3h at 500 ℃ by using hydrogen to obtain a catalyst finished product;
evaluation of catalyst:
and (2) loading the prepared catalyst into a wet oxidation reactor, mixing the wastewater with oxygen, and then carrying out catalytic wet oxidation reaction, wherein the retention time of the wastewater in the effective section of the reactor is 30min, the reaction temperature is 275 ℃, the reaction pressure is 8MPa, and the volume ratio of the oxygen to the wastewater is 300.
[ example 10 ]
Preparing a catalyst:
step 1)
Preparing 0.3mol/l TiOSO4Adding 12g of activated carbon powder into 2000ml of aqueous solution, dripping 0.6mol/l of ammonia water into the turbid solution for coprecipitation to generate a gel substance, filtering, washing, drying, and roasting at 280 ℃ for 3 hours in a nitrogen atmosphere to obtain composite carrier core powder;
step 2)
Mixing 45g of composite carrier core powder, 0.1g of ethylenediamine and 0.1g of sesbania powder, and kneading, extruding, pelleting and drying to obtain the core of the composite carrier; spraying 50g of sol with the titanium dioxide content of 10 percent on the core of the composite carrier, drying, and roasting at 900 ℃ for 4 hours to prepare the composite carrier;
step 3)
50g of the composite carrier was immersed in a cerium nitrate solution containing 1.50g of Ce. Dipping for 6h at room temperature, drying, and roasting for 2.5h at 350 ℃ to obtain a catalyst precursor;
step 4)
The catalyst precursor was immersed in H containing 0.35g of Pt2PtCl6In solution. Dipping for 6h at room temperature, drying, roasting for 3h at 400 ℃, and then reducing for 4h at 400 ℃ by using hydrogen to obtain a finished catalyst;
evaluation of catalyst:
and (2) loading the prepared catalyst into a wet oxidation reactor, mixing the wastewater with oxygen, and then carrying out catalytic wet oxidation reaction, wherein the retention time of the wastewater in the effective section of the reactor is 40min, the reaction temperature is 280 ℃, the reaction pressure is 9MPa, and the volume ratio of the oxygen to the wastewater is 250.
TABLE 1
Figure BDA0001120596870000141

Claims (9)

1. A process method for ammonium sulfate-free in an acrylonitrile reaction device comprises the following steps:
enabling a high-ammonia product gas flow (6) from the ammonia oxidation reactor to contact with a low-COD lean ammonium absorption liquid (17) in a quenching tower (1) to absorb unreacted ammonia in the high-ammonia product gas flow to obtain an ammonium-rich absorption liquid (8) and a low-ammonia product gas flow (7); stripping the ammonium-rich absorption liquid (8) in a stripping tower (2) by stripping tower stripping gas (9) to remove volatile organic components (10), separating and removing light components (11) floating on the upper layer and heavy components (12) sinking on the lower layer in a separation device (3), then heating and stripping in a stripping tower (4) by stripping tower stripping gas (13) to obtain a crude ammonia gas stream (15) and a high-COD lean ammonium absorption liquid (14), carrying out wet oxidation reaction on the high-COD lean ammonium absorption liquid (14) and an oxidant (16) in a wet oxidation reactor (5) filled with a wet oxidation catalyst to obtain a low-COD lean ammonium absorption liquid (17), and returning the low-COD lean ammonium absorption liquid (17) to the quenching tower (1) for absorbing unreacted ammonia; rectifying the crude ammonia stream (15) to obtain an anhydrous ammonia stream;
the wet oxidation catalyst comprises a carrier, and an active component and an auxiliary agent loaded on the carrier, wherein the carrier is a composite carrier taking a titanium dioxide activated carbon mixture as a core and titanium dioxide as a shell, the active component is selected from at least one of Ru, Pd and Rh, and the auxiliary agent is La.
2. The method as set forth in claim 1, characterized in that the lean ammonium absorption liquid contains at least one absorbent selected from the group consisting of phosphoric acid and ammonium dihydrogen phosphate.
3. The method of claim 1, wherein the oxidant is a molecular oxygen-containing gas.
4. The method of claim 3, wherein the oxidant is pure oxygen, air or oxygen-enriched air.
5. The method according to claim 1, wherein the wet oxidation reaction temperature is 220 to 300 ℃.
6. The method according to claim 1, wherein the wet oxidation reaction pressure is 5.0 to 12.0 MPa.
7. The method according to claim 3, wherein the volume ratio of the oxygen molecules to the high COD lean ammonium absorption solution is 50 to 400.
8. The method according to claim 1, wherein the retention time of the high COD lean ammonium absorbent solution in the wet oxidation reactor is 10 to 90 minutes.
9. The method as set forth in claim 1, characterized in that said heavy fraction (12) is a high polymer and/or an ammoxidation catalyst powder.
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