CN112973387A - Combined treatment method and system for waste water and waste gas - Google Patents

Combined treatment method and system for waste water and waste gas Download PDF

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Publication number
CN112973387A
CN112973387A CN202110379496.8A CN202110379496A CN112973387A CN 112973387 A CN112973387 A CN 112973387A CN 202110379496 A CN202110379496 A CN 202110379496A CN 112973387 A CN112973387 A CN 112973387A
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desorption
tower
absorption liquid
water
washing
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唐印
宋国天
孔德利
李家栋
秦艳妮
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Sichuan Golden Elephant Sincerity Chemical Co Ltd
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Sichuan Golden Elephant Sincerity Chemical Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/18—Absorbing units; Liquid distributors therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1412—Controlling the absorption process
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1418—Recovery of products
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1425—Regeneration of liquid absorbents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/77—Liquid phase processes
    • B01D53/78—Liquid phase processes with gas-liquid contact
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/18—Nature of the water, waste water, sewage or sludge to be treated from the purification of gaseous effluents
    • 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

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Environmental & Geological Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Treating Waste Gases (AREA)
  • Gas Separation By Absorption (AREA)

Abstract

The invention relates to the technical field of waste treatment, and discloses a combined treatment method and a combined treatment system for wastewater and waste gas. The processing method comprises the following steps: introducing the waste gas into a washing tower, and washing by using waste water as a first absorption liquid; introducing at least one part of the first absorption liquid discharged after washing into an analytical tower for analysis; condensing or dissolving the desorption gas discharged from the desorption tower in water to obtain ammonia water; the waste gas and the waste water are both generated in the production of the isophthalonitrile. A processing system, comprising: the device comprises a washing tower, a resolving tower and an ammonia carbon water collector which are sequentially communicated, wherein the ammonia carbon water collector is a condenser or an absorber. This application is with simultaneous processing waste water and waste gas, with ammonia and hydrocyanic acid recovery that wherein contains, and this system simple structure, disposable investment is little, and the working costs is low. The produced ammonia carbon water is used for SNCR denitration, and the combustion decomposition of HCN under the high-temperature condition of SNCR denitration is energy-saving and environment-friendly, and the investment is reduced.

Description

Combined treatment method and system for waste water and waste gas
Technical Field
The invention relates to the field of waste treatment, in particular to a combined treatment method and a combined treatment system for wastewater and waste gas.
Background
The raw materials for synthesizing the m-phthalonitrile are m-xylene, ammonia gas and air, and the ammoxidation reaction is carried out in a fluidized bed. Due to the excess of ammonia and air, the reaction can generate a certain amount of HCN and H2O while generating isophthalonitrile, and industrial waste gas and waste water containing NH3 and HCN can be generated through a subsequent trapping process.
The current method for treating the waste gas containing HCN and NH3 is as follows: absorbing the waste gas by water to generate waste water containing HCN and NH 3; there are many methods for treating cyanide-containing wastewater, and these methods have their advantages and disadvantages depending on the source, concentration, purpose, scale and economic requirements of wastewater. The treatment is usually carried out by physical and chemical methods such as activated carbon adsorption, electrolysis, alkalization stripping, sulfur dioxide-oxidation, alkali chloride, iron oxidation, ion exchange, chlorine dioxide and the like. But they have the disadvantages of low removal efficiency, large one-time investment, high operating cost and the like.
CN101491747A discloses a method for processing waste gas from isophthalonitrile production, in which the waste gas from isophthalonitrile production line is pretreated to remove impurities, then preheated and catalytically combusted, and HCN is oxidized to generate N2、CO2、H2And O and ammonia gas are reserved and used for producing ammonium sulfate after heat exchange with the waste gas. The method has the problems of catalyst replacement consumption, complex process, incomplete automation realization and the like.
CN109320027A discloses a system and a method for treating isophthalonitrile synthesis process wastewater, wherein in the treatment process, isophthalonitrile process wastewater is stripped, then subjected to iron-carbon-Fenton combined treatment, then subjected to anaerobic biochemical treatment, and finally subjected to A/O process treatment. The chemical method for treating the wastewater has complex process, needs to add a plurality of additional components, has higher cost and unstable treatment. And the biological treatment efficiency is low.
CN110902745A discloses a system and a method for treating waste water produced in isophthalonitrile production, which carry out multi-effect evaporation and concentration treatment on the waste water, and then carry out combustion treatment on the concentrated solution. The combustion method has the problems of denitration and dust removal of combustion tail gas and the like, the investment is large, and the energy consumption of multistage concentration of wastewater is large.
In view of this, the present application is specifically made.
Disclosure of Invention
The invention aims to provide a combined treatment method and a system for wastewater and waste gas.
The invention is realized by the following steps:
in a first aspect, an embodiment of the present application provides a combined treatment method for wastewater and waste gas, including:
introducing the waste gas into a washing tower, and washing by using waste water as a first absorption liquid;
introducing part or all of the first absorption liquid discharged after washing into an analytical tower for analysis;
condensing or dissolving the desorption gas discharged from the desorption tower in water to obtain ammonia water;
the waste gas and the waste water are both generated in the production of the isophthalonitrile.
In an optional embodiment, before introducing a part or all of the first absorption liquid discharged from the washing tower into the desorption tower, heat exchange with the desorption liquid discharged from the desorption tower is further included;
in an optional embodiment, introducing the first absorption liquid with the increased temperature after heat exchange into an analysis tower, cooling the analysis liquid with the decreased temperature after heat exchange again, and refluxing the cooled analysis liquid to a washing tower to serve as the first absorption liquid; or introducing a part of the desorption solution with the reduced temperature after heat exchange into a wastewater water removal station, and cooling the other part of the desorption solution again and refluxing the cooled desorption solution to the washing tower to be used as a first absorption solution; or cooling the temperature-reduced desorption solution again after heat exchange, introducing a part of the desorption solution into a wastewater water treatment station, cooling the other part of the desorption solution again, and refluxing the cooled desorption solution to a washing tower to serve as a first absorption solution;
in an alternative embodiment, a part of the first absorption liquid discharged from the washing tower is introduced into an absorber communicated with the desorption tower as a second absorption liquid for dissolving gas evolved by water before heat exchange, and the other part exchanges heat with the desorption liquid.
In an alternative embodiment, a part of the first absorption liquid discharged after washing is refluxed to the desorption tower to be recycled as the first absorption liquid;
in an alternative embodiment, a part of the first absorption liquid discharged after washing is introduced into the desorption tower, and the other part of the first absorption liquid is refluxed to the desorption tower to be recycled as the first absorption liquid;
or introducing a part of the first absorption liquid discharged after washing into an analysis tower, refluxing a part of the first absorption liquid to the analysis tower to be used as the first absorption liquid for recycling, and dissolving the other part of the first absorption liquid in water to be used as a second absorption liquid for the analysis gas.
In an alternative embodiment, a part of the first absorption liquid discharged after washing is refluxed to the washing tower to be recycled as the absorption liquid;
in an optional embodiment, another part of the first absorption liquid discharged after washing and the desorption liquid discharged from the desorption tower are subjected to heat exchange and then are introduced into the desorption tower;
in an optional embodiment, a part of the first absorption liquid discharged after washing and the desorption liquid discharged from the desorption tower are subjected to heat exchange and then introduced into the desorption tower; and taking the other part of the first absorption liquid discharged after washing as a second absorption liquid for dissolving gas evolution.
In an alternative embodiment, the non-condensable or water soluble stripping gas is refluxed to the scrubber to be scrubbed.
In an alternative embodiment, the ammonia carbon water is transported to an SNCR denitrification system.
In an alternative embodiment, the pressure of the scrubber is 5 to 100 kpa;
in an alternative embodiment, the pressure in the stripper column is between 10 and 200 kpa.
In a first aspect, an embodiment of the present application provides a combined wastewater and exhaust gas treatment system for implementing a method provided by the present application, including: the device comprises a washing tower, a resolving tower and an ammonia carbon water collector which are sequentially communicated, wherein the ammonia carbon water collector is a condenser or an absorber.
In an optional embodiment, the system further comprises an analysis pipeline, one end of the analysis pipeline is communicated with the liquid outlet of the washing tower, the other end of the analysis pipeline is communicated with the liquid inlet of the analysis tower, a heat exchanger is arranged on the analysis pipeline, a heat source channel of the heat exchanger is communicated with the liquid outlet of the analysis tower, and a cold source channel of the heat exchanger is communicated with the liquid outlet of the washing tower;
in an optional embodiment, a liquid outlet of the desorption tower is connected with a desorption liquid conveying pipeline, the desorption liquid conveying pipeline is communicated with a heat source channel of the heat exchanger, and a desorption pump is arranged on the desorption liquid conveying pipeline;
in an optional embodiment, the system further comprises a cooler and a first return line, one end of the first return line is communicated with the outlet of the heat source channel of the heat exchanger, the other end of the first return line is communicated with the absorption liquid inlet of the washing tower, and the cooler is arranged on the first return line;
in an alternative embodiment, the cooler comprises a circulating water cooler and a chilled water cooler which are connected in series, and a heavy component wastewater conveying pipe is arranged in front of the circulating water cooler and the chilled water cooler;
in an alternative embodiment, the system further comprises a wash pump, the wash pump being arranged on the desorption line at an upstream section of the heat exchanger;
in an alternative embodiment, the system further comprises an absorption liquid input pipe, one end of the absorption liquid input pipe is communicated with the liquid outlet of the washing tower, and the other end of the absorption liquid input pipe is communicated with the absorption liquid inlet of the absorber.
In an alternative embodiment, the system comprises a second reflux line, one end of which is in communication with the liquid discharge of the scrub column and the other end of which is in communication with the absorption liquid inlet of the scrub column.
In an optional embodiment, an air outlet of the ammonia carbon water collector is connected with a non-condensable gas return pipe, and the non-condensable gas return pipe is communicated with an air inlet of the washing tower;
in an optional embodiment, a liquid outlet of the ammonia-carbon water collector is connected with a denitration raw material production pipe. The invention has the following beneficial effects:
the application provides a waste water waste gas combined treatment system and processing method can handle the waste water and the waste gas of leaving in the isophthalonitrile synthesis workshop simultaneously, retrieves ammonia and hydrocyanic acid that contains wherein.
The system has simple structure and convenient operation, and can completely realize automatic control. The system is not only limited to the treatment of waste water and waste gas in the production of isophthalonitrile, but also can be used for the treatment of various ammonia-containing tail gases and ammonia-containing waste water.
The application provides a combined treatment system and a treatment method for waste water and waste gas, which are combined with NH3And HCN, the method is reasonable in planning, the waste water and the waste gas are reasonably utilized, the produced ammonia carbon water is used for SNCR denitration, and the SNCR denitration is used for burning and decomposing the HCN under the high-temperature condition, so that the energy is saved, the environment is protected, and the investment is reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a block diagram of a combined wastewater and exhaust gas treatment system according to a first embodiment;
FIG. 2 is a block diagram of a combined wastewater and exhaust gas treatment system according to a second embodiment;
FIG. 3 is a block diagram of a combined wastewater and exhaust gas treatment system according to a third embodiment.
Icon: 100-a waste water and waste gas combined treatment system; 110-a washing tower; 111-an exhaust gas inlet pipe; 112-a wastewater inlet pipe; 113-a blow-down pipe; 114-a second return line; 120-a washing pump; 121-absorption liquid input pipe; 130-a heat exchanger; 140-a resolution tower; 141-resolution pipeline; 142-a resolving liquid transfer line; 143-resolution pump; 150-a condenser; 151-circulating water cooler; 152-chilled water cooler; 153-a freezer unit; 154-first return line; 155-heavy component waste water conveying pipe; 160-an absorber; 161-noncondensable gas return pipe; 170-denitration raw material production pipe.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The features and properties of the present invention are described in further detail below with reference to examples.
First embodiment
As shown in fig. 1, the present embodiment provides a combined wastewater and exhaust gas treatment system 100, which includes: the scrubber 110, the desorption tower 140 and the ammonia carbon water collector are connected in sequence, and the ammonia carbon water collector is a condenser 150 in the embodiment.
Waste water discharged from an m-phthalodinitrile synthesis workshop enters the middle part of a washing tower 110 through a waste water inlet pipe 112 to serve as first absorption liquid, waste gas enters from the bottom of the washing tower 110 through a waste gas inlet pipe 111, soluble gas including ammonia and hydrocyanic acid in the waste gas in the washing tower 110 is absorbed by waste liquid, purified waste gas is discharged from an exhaust pipe 113, the waste water absorbing ammonia and hydrocyanic acid is discharged from the washing tower 110, the first absorption liquid residual liquid absorbing ammonia and hydrocyanic acid is introduced into an analytical tower 140, the ammonia and hydrocyanic acid contained in the first absorption liquid residual liquid are analyzed and then enter a condenser 150 together with water vapor discharged from a part of the analytical tower 140 to be condensed, and ammonia water is obtained.
Preferably, a liquid outlet of the condenser 150 is connected with a denitration raw material output pipe 170.
The generated ammonia carbon water is pumped into a product storage tank through the denitration raw material output pipe 170 and then conveyed to an SNCR denitration section, or is directly conveyed to the denitration section through the denitration raw material output pipe 170, and the generated ammonia carbon water can be used as SNCR denitration raw materials of coal-fired and gas-fired boilers, can realize denitration and also can reach the full combustion decomposition condition of HCN. The method is used for SNCR denitration of a boiler, and the problem of combustion tail gas treatment is not required to be considered.
The waste water and the waste gas discharged from the isophthalonitrile synthesis workshop both contain ammonia and hydrocyanic acid, and both the ammonia and the hydrocyanic acid can be recycled. The application provides a system can simultaneous processing waste water and waste gas, retrieves ammonia and hydrocyanic acid that wherein contains, and this system simple structure, disposable investment is little, and the working costs is low.
Preferably, the waste water and waste gas combined treatment system 100 further comprises a desorption pipeline 141, one end of the desorption pipeline 141 is communicated with the liquid outlet of the washing tower 110, the other end of the desorption pipeline 141 is communicated with the liquid inlet of the desorption tower 140, a heat exchanger 130 is arranged on the desorption pipeline 141, a heat source channel of the heat exchanger 130 is communicated with the liquid outlet of the desorption tower 140, and a cold source channel of the heat exchanger 130 is communicated with the liquid outlet of the washing tower 110.
The first absorption liquid raffinate is conveyed to the heat exchanger 130 along the desorption pipeline 141, exchanges heat with the high-temperature desorption liquid in the heat exchanger 130, and ammonia and hydrocyanic acid in the desorption tower 140 are desorbed after the temperature of the first absorption liquid raffinate is increased. The first absorption liquid raffinate after the temperature rise enters the desorption tower 140 for desorption, so that the energy supply during desorption can be saved.
Preferably, the system further comprises a washing pump 120, and the washing pump 120 is arranged on a resolving line 141 and is positioned at an upstream section of the heat exchanger 130.
The wash pump 120 is used to pump the first absorption liquid raffinate to the heat exchanger 130 and the stripper 140. In other embodiments of the present application, the washing pump 120 may not be provided, and the first absorption liquid residue may be fed into the heat exchanger 130 and the desorption tower 140 by self-pressure by setting the washing tower 110 at a high position and utilizing the height difference between the washing tower 110 and the desorption pump 143.
Preferably, a desorption liquid conveying pipeline 142 is connected to a liquid outlet of the desorption tower 140, the desorption liquid conveying pipeline 142 is communicated with a heat source channel of the heat exchanger 130, and a desorption pump 143 is disposed on the desorption liquid conveying pipeline 142.
The desorption pump 143 is used to pump the desorption solution discharged from the desorption tower 140 to the heat exchanger 130 and the first reflux line 154. In another embodiment of the present invention, the analysis pump 143 may be omitted, and the analysis liquid may be fed into the heat exchanger 130 and the first return line 154 by pressure by setting the analysis column 140 at a high position and utilizing the difference in height between the analysis column 140, the heat exchanger 130, and the washing column 110.
Preferably, the combined wastewater and exhaust gas treatment system 100 further includes a cooler and a first return line 154, one end of the first return line 154 is communicated with an outlet of the heat source passage of the heat exchanger 130, and the other end is communicated with an absorption liquid inlet of the scrubber 110, and the cooler is disposed on the first return line 154.
Since the desorption solution discharged from the desorption tower 140 contains almost no ammonia gas and hydrocyanic acid, the desorption solution can be returned to the washing tower 110 through the first return line 154 after heat exchange and temperature reduction for recycling as the first absorption solution. Although the temperature of the desorption solution after heat exchange is reduced, the desorption solution still has a higher temperature as the first absorption solution, and therefore the temperature of the desorption solution needs to be reduced again by a cooler before entering the washing tower 110, so as to avoid the phenomenon that the high-temperature absorption solution cannot completely absorb the soluble gas in the exhaust gas, and the exhaust gas does not reach the standard.
Specifically, the cooler comprises a circulating water cooler 151 and a chilled water cooler 152 which are connected in series, the chilled water cooler 152 is connected with a refrigerating unit 153, and the temperature of the chilled water is 0-20 ℃. A heavy component wastewater conveying pipe 155 is arranged in front of the circulating water cooler 151 and the chilled water cooler 152.
The desorption liquid is cooled by two stages and then is used as a first absorption liquid, and part of the desorption liquid is conveyed to a water chemical station for treatment through a heavy component wastewater conveying pipe 155.
Preferably, a non-condensable gas return pipe 161 is connected to the air outlet of the condenser 150, and the non-condensable gas return pipe 161 is communicated with the air inlet of the washing tower 110.
The gas that is not condensed in the gas desorbed from the desorption tower 140 is returned to the washing tower 110 through the noncondensable gas return pipe 161, and is washed again by the first absorption liquid.
The embodiment also provides a combined treatment method of wastewater and waste gas, which specifically comprises the following steps:
pressurizing the waste gas generated in the production of the isophthalonitrile to 5-100 kpa, bubbling the waste gas into the bottom of a washing tower 110 through a waste gas inlet pipe 111, and introducing the waste water generated in the production of the isophthalonitrile into the washing tower 110 through a waste water inlet pipe 112 to be used as a first absorption liquid for washing the waste gas. The ammonia gas and the hydrocyanic acid in the exhaust gas are dissolved in the wastewater.
The first absorption liquid discharged after washing is pumped to the heat exchanger 130 as a cold source through the washing pump 120, the desorption liquid discharged from the desorption tower 140 is pumped to the heat exchanger 130 as a heat source through the desorption pump 143, and the first absorption liquid discharged after washing and the desorption liquid exchange heat.
The temperature of the first absorption liquid after heat exchange is increased, and the first absorption liquid is pumped into an analytical tower 140, the pressure of the analytical tower 140 is controlled to be 10-200 kpa, and the analytical tower 140 analyzes the first absorption liquid, so that ammonia gas and hydrocyanic acid in the first absorption liquid are separated out.
The desorption gas (ammonia and hydrocyanic acid) discharged from the desorption tower 140 is introduced into a condenser 150 to be condensed to obtain ammonia water with the concentration of 20-40 wt%. The ammonia water can be injected into the product storage tank and then enters the product storage tank through the denitration raw material production pipe 170 or is conveyed to the SNCR denitration section to be used as a raw material.
The temperature of the desorbed solution after heat exchange is increased, and after the temperature of the desorbed solution is reduced by the circulating water cooler 151, a part of the desorbed solution is introduced into the water chemical station through the heavy component wastewater delivery pipe 155, and the other part of the desorbed solution reaches the chilled water cooler 152, is cooled again, and then flows back to the washing tower 110 along the first return line 154 to be used as the first absorption solution.
Second embodiment
As shown in fig. 2, the system and method provided by the present embodiment have the same implementation principle and technical effect as the first embodiment, and for the sake of brief description, reference may be made to the corresponding contents in the first embodiment without reference to the present embodiment.
In the system provided in this embodiment, the ammonia-carbon water collector is the absorber 160, and may specifically be the bubble absorber 160, since the ammonia gas and the hydrocyanic acid are dissolved in water, the absorber 160 may use water as the second absorption liquid, and the gas produced in the desorption tower 140 is absorbed by the absorber 160 to obtain the ammonia-carbon water.
Preferably, the combined wastewater and exhaust gas treatment system 100 provided by this embodiment further includes an absorption liquid input pipe 121, and one end of the absorption liquid input pipe 121 is communicated with the liquid discharge port of the washing tower 110, and the other end is communicated with the absorption liquid inlet of the absorber 160.
The absorption liquid discharged from the absorption tower may be used as a second absorption liquid for capturing ammonia water and hydrocyanic acid. The absorber 160 is adopted, and the absorption liquid discharged from the absorption tower is used as the absorption liquid of the absorption tower, so that the concentration of the finally obtained ammonia water can be regulated and controlled by controlling the introduction amount of the absorption liquid.
In the method provided in this embodiment, the desorption gas discharged from the desorption tower 140 is introduced into the absorber 160, absorbed by the second absorption liquid to obtain ammonia-containing water, and then pumped into the product storage tank for storage, or conveyed to the denitration section through the denitration raw material output pipe 170.
The second absorption liquid is the first absorption liquid residue which is sent to the absorber 160 through the absorption liquid input pipe 121. The concentration of ammonia water finally obtained by adjusting the introduction amount of the first absorption liquid residual liquid is 10-15% wt.
Third embodiment
As shown in fig. 3, the system and method provided by the present embodiment have the same implementation principle and technical effect as the first embodiment, and for the sake of brief description, reference may be made to the corresponding contents in the first embodiment without reference to the present embodiment.
In the system provided in this embodiment, the combined wastewater and exhaust gas treatment system 100 further includes a second return line 114, and one end of the second return line 114 is communicated with the liquid outlet of the scrubber 110, and the other end is communicated with the absorption liquid inlet of the scrubber 110.
A portion of the absorption liquid discharged from the scrubber 110 may be refluxed to the scrubber 110 for waste gas scrubbing again.
In the method provided by this embodiment, the first absorption liquid raffinate produced in the scrubber 110 is recycled by the second reflux line 114 to the liquid inlet of the scrubber 110 for recycling as the first absorption liquid.
To sum up, the waste water and waste gas combined treatment system and the treatment method provided by the application can be used for simultaneously treating waste water and waste gas discharged from an m-phthalonitrile synthesis workshop and recovering ammonia and hydrocyanic acid contained in the waste water and waste gas. The system has simple structure and convenient operation, and can completely realize automatic control. The system is not only limited to the treatment of waste water and waste gas in the production of isophthalonitrile, but also can be used for the treatment of various ammonia-containing tail gases and ammonia-containing waste water. The application provides a combined treatment system and a treatment method for waste water and waste gas, which are combined with NH3And HCN, the method is reasonable in planning, the waste water and the waste gas are reasonably utilized, the produced ammonia carbon water is used for SNCR denitration, and the SNCR denitration is used for burning and decomposing the HCN under the high-temperature condition, so that the energy is saved, the environment is protected, and the investment is reduced.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A combined treatment method for waste water and waste gas is characterized by comprising the following steps:
introducing the waste gas into a washing tower, and washing by using waste water as a first absorption liquid;
introducing part or all of the first absorption liquid discharged after washing into an analytical tower for analysis;
condensing or dissolving the desorption gas discharged from the desorption tower in water to obtain ammonia water;
the waste gas and the waste water are both generated in the production of the isophthalonitrile.
2. The combined wastewater and waste gas treatment method according to claim 1, characterized in that before introducing a part or all of the first absorption liquid discharged from the washing tower into the desorption tower, the method further comprises heat exchange with the desorption liquid discharged from the desorption tower;
preferably, the first absorption liquid with the increased temperature after heat exchange is introduced into the desorption tower, and the desorption liquid with the decreased temperature after heat exchange is cooled again and then flows back to the washing tower to be used as the first absorption liquid; or introducing a part of the desorption solution with the reduced temperature after heat exchange into a wastewater water removal station, and cooling the other part of the desorption solution again and refluxing the cooled desorption solution to the washing tower to be used as a first absorption solution; or cooling the temperature-reduced desorption solution again after heat exchange, introducing a part of the desorption solution into a wastewater water treatment station, cooling the other part of the desorption solution again, and refluxing the cooled desorption solution to a washing tower to serve as a first absorption solution;
preferably, a part of the first absorption liquid discharged from the washing tower is introduced into an absorber communicated with the desorption tower as a second absorption liquid dissolving the desorbed gas in water before heat exchange, and the other part of the first absorption liquid exchanges heat with the desorbed liquid.
3. The combined wastewater and waste gas treatment method according to claim 1, wherein a part of the first absorption liquid discharged after washing is refluxed to the desorption tower to be recycled as the first absorption liquid;
preferably, a part of the first absorption liquid discharged after washing is introduced into the desorption tower, and the other part of the first absorption liquid flows back to the desorption tower to be recycled as the first absorption liquid;
or introducing a part of the first absorption liquid discharged after washing into an analysis tower, refluxing a part of the first absorption liquid to the analysis tower to be used as the first absorption liquid for recycling, and dissolving the other part of the first absorption liquid in water to be used as a second absorption liquid for the analysis gas.
4. The integrated wastewater and waste gas treatment method according to claim 1, wherein the uncondensable or water-soluble desorbed gas is refluxed to the scrubber for further scrubbing.
5. The combined wastewater and exhaust gas treatment method according to claim 1, wherein the ammonia-carbon water is transported to an SNCR denitration system.
6. The combined wastewater and waste gas treatment method according to claim 1, wherein the pressure of the washing tower is 5-100 kpa;
preferably, the pressure of the desorption tower is 10-200 kpa.
7. A combined wastewater and exhaust gas treatment system for carrying out the method according to any one of claims 1 to 6, comprising: the device comprises a washing tower, a resolving tower and an ammonia carbon water collector which are sequentially communicated, wherein the ammonia carbon water collector is a condenser or an absorber.
8. The combined wastewater and waste gas treatment system according to claim 7, further comprising a desorption pipeline, wherein one end of the desorption pipeline is communicated with the liquid outlet of the washing tower, the other end of the desorption pipeline is communicated with the liquid inlet of the desorption tower, a heat exchanger is arranged on the desorption pipeline, a heat source channel of the heat exchanger is communicated with the liquid outlet of the desorption tower, and a cold source channel of the heat exchanger is communicated with the liquid outlet of the washing tower;
preferably, a liquid outlet of the desorption tower is connected with a desorption liquid conveying pipeline, the desorption liquid conveying pipeline is communicated with a heat source channel of the heat exchanger, and a desorption pump is arranged on the desorption liquid conveying pipeline;
preferably, the system further comprises a cooler and a first return line, one end of the first return line is communicated with the outlet of the heat source channel of the heat exchanger, and the other end of the first return line is communicated with the absorption liquid inlet of the washing tower, and the cooler is arranged on the first return line; further preferably, the cooler comprises a circulating water cooler and a chilled water cooler which are connected in series, and a heavy component wastewater conveying pipe is arranged in front of the circulating water cooler and the chilled water cooler;
preferably, the system further comprises a washing pump, wherein the washing pump is arranged on the resolving pipeline and is positioned at an upstream section of the heat exchanger;
preferably, the system further comprises an absorption liquid input pipe, one end of the absorption liquid input pipe is communicated with the liquid outlet of the washing tower, and the other end of the absorption liquid input pipe is communicated with the absorption liquid inlet of the absorber.
9. The combined wastewater and waste gas treatment system according to claim 7, wherein the system comprises a second return line, one end of the second return line is communicated with the liquid outlet of the washing tower, and the other end of the second return line is communicated with the absorption liquid inlet of the washing tower.
10. The combined wastewater and waste gas treatment system according to claim 7, wherein a non-condensable gas return pipe is connected to the gas outlet of the ammonia water collector and is communicated with the gas inlet of the washing tower;
preferably, a liquid outlet of the ammonia-water collector is connected with a denitration raw material output pipe.
CN202110379496.8A 2021-04-08 2021-04-08 Combined treatment method and system for waste water and waste gas Pending CN112973387A (en)

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CN202110379496.8A CN112973387A (en) 2021-04-08 2021-04-08 Combined treatment method and system for waste water and waste gas

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CN202110379496.8A CN112973387A (en) 2021-04-08 2021-04-08 Combined treatment method and system for waste water and waste gas

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CN112973387A true CN112973387A (en) 2021-06-18

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CN202110379496.8A Pending CN112973387A (en) 2021-04-08 2021-04-08 Combined treatment method and system for waste water and waste gas

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