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CN112939812A - Chlorothalonil production process - Google Patents

Chlorothalonil production process Download PDF

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Publication number
CN112939812A
CN112939812A CN202110169677.8A CN202110169677A CN112939812A CN 112939812 A CN112939812 A CN 112939812A CN 202110169677 A CN202110169677 A CN 202110169677A CN 112939812 A CN112939812 A CN 112939812A
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chlorine
ipn
gas
vaporizer
nitrogen
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CN112939812B (en
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王海波
禚文峰
王振宇
王潭
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Jiangsu Xinhe Agricultural Chemical Co ltd
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Jiangsu Xinhe Agricultural Chemical Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C253/00—Preparation of carboxylic acid nitriles
    • C07C253/30—Preparation of carboxylic acid nitriles by reactions not involving the formation of cyano groups
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/56—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with multiple filtering elements, characterised by their mutual disposition
    • B01D46/62—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with multiple filtering elements, characterised by their mutual disposition connected in series
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1456—Removing acid components
    • 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
    • B01D53/1493—Selection of liquid materials for use as 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
    • B01D53/68—Halogens or halogen compounds
    • 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

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  • Chemical Kinetics & Catalysis (AREA)
  • Analytical Chemistry (AREA)
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  • Oil, Petroleum & Natural Gas (AREA)
  • Environmental & Geological Engineering (AREA)
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  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The invention provides a chlorothalonil production process, which comprises the steps of respectively introducing a mixed gas of vaporized isophthalonitrile and nitrogen and chlorine into a reactor for chlorination reaction, and carrying out post-treatment on a reaction gas obtained by the chlorination reaction to obtain chlorothalonil. The production process of chlorothalonil can reduce the mixing step before entering the reactor, avoid side reaction in the mixing process, prevent the side product from attaching to the pore plate with catalyst distributed after entering the fluidized bed, ensure the conversion rate of chlorination reaction to be always in the target level, prolong the period of shutdown and maintenance, reduce material consumption and produce high-quality chlorothalonil product with hexachlorobenzene content less than or equal to 10 ppm.

Description

Chlorothalonil production process
Technical Field
The invention relates to the technical field of chemical production, in particular to a chlorothalonil production process.
Background
Chlorothalonil, chemically named tetrachloroisophthalonitrile, is a high-efficiency, low-toxicity, broad-spectrum and low-residue protective bactericide, is widely applied to the control of fungal diseases in agriculture and forestry, is particularly applied to economic crops such as vegetables and fruits, and is also applied to the sterilization of golf courses, lawns, ornamental plants and the like; in addition, chlorothalonil has important application in the mildew-proof industrial field, such as mildew-proof coating, mildew-proof wallpaper, mildew-proof of electric appliances, mildew-proof of wood and the like. Chlorothalonil is usually obtained by a gas phase chlorination process, and the production scale at home and abroad is continuously enlarged, so that chlorothalonil becomes one of large-tonnage excellent pesticide varieties in the world.
At present, the production process of chlorothalonil mainly adopts an m-phthalonitrile direct chlorination method, m-phthalonitrile (IPN) is melted and then sent into a vaporizer to be vaporized, then is mixed with part of nitrogen to obtain an IPN mixed gas, then chlorine after drying and preheating is uniformly mixed with the IPN mixed gas, and then the chlorine enters a reactor to carry out chlorination reaction. The reactor generally adopts a combined process of a fluidized bed and a fixed bed, reaction gas obtained by reaction enters a catcher, chlorothalonil is condensed and separated out and is continuously sent out to obtain a product, and the yield is over 90 percent. The tail gas mainly comprises chlorine, hydrogen chloride and nitrogen, and is treated by a recovery treatment system.
CN100404500C discloses a method for producing chlorothalonil with low hexachlorobenzene content, which comprises the steps of adding isophthalonitrile into a vaporizer for vaporization, wherein the feeding amount is 1 mol/hr; the method comprises the steps of carrying out a first-step reaction in a fluidized bed, mixing a reaction product with chlorine again, wherein the chlorine flow is 2-5 times of the feeding amount of the isophthalonitrile, feeding the mixture into a fixed bed for chlorination, feeding the obtained reaction mixed gas into a material receiver, and condensing and collecting to obtain a chlorothalonil product.
CN102718682A discloses a preparation method of chlorothalonil, which comprises the following steps: sending a certain amount of isophthalonitrile into a vaporizer for vaporization, taking the isophthalonitrile out of the vaporizer by nitrogen after vaporization, mixing the isophthalonitrile with chlorine in a mixer, and then entering a fluidized bed, wherein the molar ratio of the air inflow is isophthalonitrile: chlorine gas: adding special ammonia oxidation catalyst into nitrogen (3-4): 8-10): 15-18; the second step is that: and (3) feeding the gas after the first-step reaction into a fixed bed, keeping the temperature and the pressure as same as those of the fluidized bed, adding catalyst and chlorine gas in the same amount as those of the fluidized bed, reacting the gas after the first reaction with the chlorine gas again, feeding the mixed gas after the reaction in the fixed bed into a material collector after the reaction is finished, and drying the mixed gas after the reaction in the fixed bed to obtain chlorothalonil after condensation.
CN104447407B discloses a method for preparing chlorothalonil with hexachlorobenzene content lower than 10ppm, which comprises the following steps: step one, activating a catalyst, namely filling modified coconut shell activated carbon into a fluidized bed and a fixed bed, heating to remove water under the protection of nitrogen, and then heating to activate the coconut shell activated carbon by introducing chlorine until no hydrogen chloride gas exists in tail gas; step two, preprocessing the isophthalonitrile, namely melting and vaporizing the raw material isophthalonitrile, and taking the vaporized isophthalonitrile out of a vaporizer by using nitrogen; step three, chlorination, namely dividing the amount of chlorine required by the reaction into two parts, mixing the chlorine of 2/3 with the isophthalonitrile gas containing nitrogen in the step two, entering the mixture into a fluidized bed, completing the first-step reaction in the fluidized bed, and then mixing the gas of the first-step reaction with the residual 1/3 chlorine, entering the fixed bed for a supplementary reaction; step four, post-treatment, cooling the reacted gas to obtain tetrachloroisophthalonitrile crystal powder, and sequentially using water and FeCl for tail gas generated by the reaction2、Ca(OH)2And (4) absorbing.
The prior art is all after the isophthalonitrile gas that will contain nitrogen gas and chlorine misce bene, the rethread carries out chlorination in the fluidized bed, however, because the chemical property of chlorine is unusual lively, and the mixing process is in higher temperature, make a series of side reactions can take place in the mixing process, generate complicated solid-state or liquid accessory substance, can adhere to on the orifice plate that distributes there is the catalyst after getting into the fluidized bed, and then cause the orifice plate to block up, influence chlorination's conversion, lead to the cycle of shutting down the maintenance to shorten greatly. Therefore, there is a need to develop a new production process of chlorothalonil.
Disclosure of Invention
In view of the problems in the prior art, the invention provides a chlorothalonil production process, wherein a mixed gas of vaporized isophthalonitrile and nitrogen and chlorine are respectively introduced into a reactor for chlorination reaction, and a reaction gas obtained by the chlorination reaction is subjected to post-treatment to obtain chlorothalonil. The production process of chlorothalonil can reduce the mixing step before entering the reactor, avoid side reaction in the mixing process, prevent the side product from attaching to the pore plate with catalyst distributed after entering the fluidized bed, ensure the conversion rate of chlorination reaction to be always in the target level, prolong the period of shutdown and maintenance, reduce material consumption and produce high-quality chlorothalonil product with hexachlorobenzene content less than or equal to 10 ppm.
In order to achieve the purpose, the invention adopts the following technical scheme:
one of the purposes of the invention is to provide a chlorothalonil production process, wherein vaporized isophthalonitrile is mixed with nitrogen to obtain a mixed gas, then the mixed gas and chlorine are respectively introduced into a reactor to carry out chlorination reaction, and the reaction gas obtained by the chlorination reaction is subjected to post-treatment to obtain chlorothalonil.
The production process of chlorothalonil can reduce the mixing step before entering the reactor, avoid side reaction in the mixing process, prevent the side product from attaching to the pore plate with catalyst distributed after entering the fluidized bed, ensure the conversion rate of chlorination reaction to be always in the target level, prolong the period of shutdown and maintenance, reduce material consumption and produce high-quality chlorothalonil product with hexachlorobenzene content less than or equal to 10 ppm.
As a preferable technical scheme of the invention, the preparation method of the mixed gas comprises the following steps:
and feeding the raw material isophthalonitrile into an IPN melter for heating, feeding the obtained liquid isophthalonitrile into an IPN vaporizer through an IPN flowmeter, feeding from an upper feeding port of the IPN vaporizer, feeding nitrogen into the IPN vaporizer through a nitrogen flowmeter, feeding from a lower feeding port of the IPN vaporizer, and feeding the gas obtained from an outlet of the IPN vaporizer into a gas mixer for further mixing to obtain the mixed gas.
As a preferable technical scheme of the invention, the raw material isophthalonitrile is in a liquid state and/or a solid state.
Preferably, the solid raw material isophthalonitrile is conveyed to the IPN melter through an IPN auger, and the liquid raw material isophthalonitrile is directly introduced into the IPN melter.
Preferably, the purity of the raw material isophthalonitrile is more than or equal to 99 percent, and preferably, the purity is more than or equal to 99.5 percent.
Preferably, an IPN buffer tank is disposed between the IPN melter and the IPN flow meter, and the liquid isophthalonitrile obtained by the IPN melter is introduced into the IPN buffer tank through a delivery pump.
And liquid isophthalonitrile from the IPN melter enters the IPN buffer tank through a jacket pipe, the jacket pipe is insulated by using heat conduction oil, and the temperature in the jacket pipe is maintained to be higher than the melting point of the isophthalonitrile, so that the isophthalonitrile is effectively prevented from crystallizing in the pipe to cause blockage.
Preferably, the heating medium of the IPN melter comprises any one or a combination of at least two of a diathermic oil, a molten salt or superheated steam, preferably a diathermic oil.
Preferably, the flow rate of the heat conducting oil in the IPN melter is 10-100m3H, e.g. 10m3/h、20m3/h、25m3/h、30m3/h、35m3/h、40m3/h、45m3/h、50m3/h、70m3/h、90m3H or 100m3H etc., preferably from 25 to 50m3And/h, but not limited to, the recited values, and other values not recited within the range of values are equally applicable.
Preferably, the temperature of the IPN melter is 170-240 deg.C, such as 170 deg.C, 180 deg.C, 190 deg.C, 200 deg.C, 210 deg.C, 220 deg.C, 230 deg.C or 240 deg.C, preferably 180-220 deg.C, but is not limited to the recited values, and other non-recited values within the range are equally applicable.
Preferably, the material of the IPN melter comprises any one or a combination of at least two of carbon steel, stainless steel, hastelloy, nickel alloy or monel, preferably stainless steel.
As a preferred embodiment of the present invention, the delivery amount of the delivery pump is 1500-kg/h, 100-kg/h, 200-kg/h, 400-kg/h, 500-kg/h, 800-kg/h, 1000-kg/h, 1200-kg/h or 1500-kg/h, etc., preferably 200-1400-kg/h, but the present invention is not limited to the above-mentioned values, and other values not listed in the above-mentioned range are also applicable.
Preferably, a pipe filter is disposed at an inlet of the transfer pump, so that the pipeline and the transfer pump can be prevented from being clogged by insoluble substances in the isophthalonitrile.
Preferably, the temperature of the IPN buffer tank is 170-240 ℃, such as 170 ℃, 180 ℃, 190 ℃, 200 ℃, 210 ℃, 220 ℃, 230 ℃ or 240 ℃, preferably 180-220 ℃, but is not limited to the recited values, and other unrecited values within the range of values are equally applicable.
Preferably, the material of the IPN buffer tank includes any one or a combination of at least two of carbon steel, stainless steel, hastelloy, nickel alloy and monel, and is preferably stainless steel.
Preferably, the temperature of the IPN vaporizer is 200-330 deg.C, such as 200 deg.C, 230 deg.C, 250 deg.C, 280 deg.C, 300 deg.C or 330 deg.C, and preferably 250-300 deg.C, but is not limited to the recited values, and other values not recited within the range of values are equally applicable.
Preferably, the material of the IPN vaporizer includes any one or a combination of at least two of carbon steel, stainless steel, hastelloy, nickel alloy, or monel, preferably stainless steel.
Preferably, the IPN vaporizer is a horizontal blade vaporizer or a vertical blade vaporizer, preferably a vertical blade vaporizer.
As the preferable technical scheme of the invention, nitrogen firstly enters a nitrogen buffer tank, then enters a nitrogen heater for heating through the nitrogen flowmeter, and then enters the IPN vaporizer.
Preferably, the purity of the nitrogen is more than or equal to 99.5 percent.
Preferably, the nitrogen flow meter is a volumetric flow meter or a mass flow meter, preferably a volumetric flow meter.
Preferably, the flow rate of the nitrogen gas flowmeter is 300-2000m3H, e.g. 300m3/h、400m3/h、700m3/h、1000m3/h、1200m3/h、1500m3/h、1800m3H or 2000m3H, etc., preferably 400-1800m3And/h, but not limited to, the recited values, and other values not recited within the range of values are equally applicable.
Preferably, the pressure of the nitrogen buffer tank is 0.3 to 0.6MPa, such as 0.3MPa, 0.35MPa, 0.4MPa, 0.45MPa, 0.5MPa or 0.6MPa, but not limited to the values listed, and other values not listed within this range are equally applicable.
Preferably, the outlet temperature of the nitrogen heater is 200-.
Preferably, the heating medium of the nitrogen heater comprises any one of or a combination of at least two of heat transfer oil, molten salt or superheated steam, preferably heat transfer oil.
As a preferred technical scheme of the invention, liquid chlorine is vaporized by a liquid chlorine vaporizer to obtain chlorine, and then the chlorine sequentially passes through a chlorine buffer tank, a chlorine flow meter and a chlorine heater and then enters the reactor.
Preferably, the liquid chlorine vaporizer is heated using a water heater.
Preferably, the water flow rate of the water heater is 10-100m3H, e.g. 10m3/h、30m3/h、50m3/h、80m3/h、90m3H or 100m3H, etc., preferably from 30 to 80m3And/h, but not limited to, the recited values, and other values not recited within the range of values are equally applicable.
Preferably, the liquid chlorine vaporizer has a temperature of 71 to 90 ℃, for example 71 ℃, 75 ℃, 80 ℃, 82 ℃, 85 ℃, 87 ℃ or 90 ℃, preferably 80 to 90 ℃, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.
Preferably, the heat exchange area of the liquid chlorine vaporizer is 50-200m2E.g. 50m2、70m2、100m2、120m2、150m2、180m2Or 200m2Etc., preferably 100-2However, the numerical values recited are not intended to be limiting, and other numerical values not recited within the numerical range may be equally applicable.
Preferably, the pressure of the chlorine buffer tank is 0.3 to 0.6MPa, for example, 0.3MPa, 0.35MPa, 0.4MPa, 0.45MPa, 0.5MPa or 0.6MPa, and preferably 0.3 to 0.4MPa, but the pressure is not limited to the values listed, and other values not listed in the numerical range are also applicable.
Preferably, the chlorine flow meter is a volumetric flow meter or a mass flow meter, preferably a mass flow meter.
Preferably, the heating medium of the chlorine heater comprises any one of heat transfer oil, molten salt or superheated steam or a combination of at least two of the heat transfer oil, preferably heat transfer oil.
Preferably, the outlet temperature of the chlorine heater is 280-350 ℃, such as 280 ℃, 290 ℃, 300 ℃, 310 ℃, 320 ℃, 330 ℃, 340 ℃ or 350 ℃, and the like, preferably 300-330 ℃, but is not limited to the recited values, and other unrecited values within the range of values are equally applicable.
As a preferable technical scheme of the invention, the mixed gas enters from the bottom of the reactor through a distribution plate, the chlorine gas enters from the bottom of the reactor through a chlorine gas distributor, and a gas outlet of the chlorine gas distributor is over against a gas outlet of the distribution plate, so that the mixed gas and the chlorine gas flow in a reverse direction.
Preferably, the reactor is operated at a gas velocity of 0.5 to 4m/s, such as 0.5m/s, 1m/s, 1.5m/s, 2m/s, 2.5m/s, 3m/s, 3.5m/s or 4m/s, etc., preferably 1 to 2m/s, but not limited to the values listed, and other values not listed in this range of values are equally applicable.
Preferably, the gas velocity of the gas mixture discharged from the gas outlet of the distribution plate is 10 to 20m/s, for example, 10m/s, 12m/s, 13m/s, 15m/s, 16m/s, 18m/s, or 20m/s, but is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.
Preferably, the gas velocity of the chlorine gas ejected from the gas outlet of the chlorine gas distributor is 10 to 20m/s, for example, 10m/s, 12m/s, 13m/s, 15m/s, 16m/s, 18m/s or 20m/s, but is not limited to the values listed, and other values not listed in the numerical range are also applicable.
Preferably, the molar ratio of nitrogen to isophthalonitrile in the mixed gas is (5-5.5):1, for example, 5:1, 5.1:1, 5.2:1, 5.3:1, 5.4:1 or 5.5:1, but not limited to the recited values, and other values not recited in the numerical range are also applicable.
Preferably, the mass ratio of chlorine to phthalonitrile in the gas mixture in the reactor is controlled to be (2.4-2.5):1, for example 2.4:1, 2.42:1, 2.45:1, 2.47:1 or 2.5:1, but not limited to the values listed, and other values not listed in this range of values are equally suitable.
Preferably, the chlorine distributor comprises a pipe distributor, a nozzle distributor, a plate distributor, preferably a pipe distributor.
Preferably, the diameter of the gas holes of the chlorine distributor is 5-25mm, such as 5mm, 10mm, 15mm, 20mm or 25mm, etc., and the distance between any two adjacent gas holes is 100-200mm, such as 100mm, 120mm, 150mm, 170mm or 200mm, etc., but it is not limited to the recited values, and other values not recited in the above-mentioned value range are also applicable.
Preferably, the chlorine distributor has an open porosity of 0.75-3%, such as 0.75%, 1%, 1.5%, 2%, 2.5% or 3%, and preferably 1-2%, but is not limited to the recited values, and other values not recited within this range are equally applicable.
Preferably, the chlorine gas distributor material comprises any one or a combination of at least two of carbon steel, stainless steel, hastelloy, a nickel alloy, or monel, preferably monel.
As a preferred technical scheme of the invention, the reactor is a fluidized bed reactor.
Preferably, the temperature of the fluidized bed reactor is 280-350 ℃, such as 280 ℃, 290 ℃, 300 ℃, 310 ℃, 320 ℃, 330 ℃, 340 ℃ or 350 ℃, etc., preferably 310-330 ℃, but is not limited to the recited values, and other unrecited values within the range of values are equally applicable.
Preferably, the fluidized bed reactor has a diameter of 2000-.
Preferably, the heating medium of the fluidized bed reactor comprises any one of or a combination of at least two of a heat transfer oil, a molten salt or superheated steam, preferably a heat transfer oil.
As a preferable technical solution of the present invention, the post-processing includes: and (2) enabling the reaction gas obtained by the chlorination reaction to sequentially pass through a bag filter, a fixed bed filter, a trap, a tail gas filter and a tail gas processor, obtaining chlorothalonil by utilizing the trap, and discharging gas discharged from the tail gas processor at high altitude.
Preferably, the bag filter outlet temperature is 250-350 ℃, such as 250 ℃, 270 ℃, 300 ℃, 310 ℃, 320 ℃, 330 ℃ or 350 ℃, and the like, preferably 300-330 ℃, but is not limited to the recited values, and other values not recited within the range of values are equally applicable.
Preferably, the filtration area of the bag filter is 30-150m2E.g. 30m2、50m2、70m2、100m2、110m2、120m2、130m2、140m2Or 150m2Etc., preferably 100-2However, the numerical values recited are not intended to be limiting, and other numerical values not recited within the numerical range may be equally applicable.
Preferably, the material of the filter bag in the bag filter comprises PTFE, PI or WETF, and PTFE is preferred.
Preferably, the material of the bag filter comprises any one or a combination of at least two of stainless steel, hastelloy, nickel alloy and monel, and is preferably stainless steel.
Preferably, the bag filter has a diameter of 1000-.
Preferably, the fixed bed filter has a diameter of 1000-.
Preferably, the fixed bed filter comprises any one of axial adiabatic, radial adiabatic, or shell-and-tube, preferably shell-and-tube.
Preferably, the material of the fixed bed filter comprises any one or a combination of at least two of carbon steel, stainless steel, hastelloy, nickel alloy and monel, and is preferably stainless steel.
Preferably, the outlet temperature of the fixed bed filter is 200-.
Preferably, the cooling means of the trap comprises air cooling, water cooling or oil cooling, preferably air cooling.
Preferably, the trap comprises a first trap, a second trap and a third trap connected in series.
Preferably, the temperature of the first trap is 250-300 ℃, such as 250 ℃, 260 ℃, 265 ℃, 270 ℃, 275 ℃ or 280 ℃, and preferably 260-280 ℃, but is not limited to the recited values, and other unrecited values within the range of values are equally applicable.
Preferably, the temperature of the second trap is 150-.
Preferably, the temperature of the third trap is 100-150 ℃, such as 100 ℃, 110 ℃, 115 ℃, 120 ℃, 130 ℃, 140 ℃ or 150 ℃, preferably 110-120 ℃, but is not limited to the recited values, and other values not recited in the range of values are equally applicable.
Preferably, the diameter of the exhaust gas filter is 1000-.
Preferably, the filtering area of the tail gas filter is 10-200m2E.g. 10m2、50m2、100m2、120m2、140m2、150m2、170m2、190m2Or 200m2Etc., preferably 100-2However, the numerical values recited are not intended to be limiting, and other numerical values not recited within the numerical range may be equally applicable.
Preferably, the tail gas processor absorbs hydrogen chloride by using water through a falling film absorber and absorbs chlorine by using a liquid alkali solution.
Preferably, the process water for absorbing hydrogen chloride comprises any one of deep well water, recycled water or soft water or a combination of at least two of the same, preferably recycled water.
Preferably, the hydrochloric acid concentration discharged from the falling film absorber is controlled to be 20-30%, such as 20%, 25%, 26%, 27%, 28%, 29%, 30% or the like, preferably 25-30%, but is not limited to the recited values, and other values not recited in the range of values are also applicable.
Preferably, the concentration of the liquid caustic solution is controlled to be 10-30%, for example, 10%, 15%, 17%, 18%, 20%, 25%, or 30%, etc., preferably 15-20%, but is not limited to the recited values, and other values not recited within the range of values are also applicable.
Preferably, the spraying amount of the liquid alkali solution is controlled to be 10-80m3H, e.g. 10m3/h、20m3/h、30m3/h、40m3/h、50m3/h、60m3H or 80m3H, etc., preferably 20 to 50m3And/h, but not limited to, the recited values, and other values not recited within the range of values are equally applicable.
The preferable technical scheme of the invention comprises the following steps:
(1) preparing a mixed gas of vaporized isophthalonitrile and nitrogen:
feeding raw material isophthalonitrile into an IPN melter for heating, wherein solid raw material isophthalonitrile is conveyed to the IPN melter through an IPN spiral feeder, liquid raw material isophthalonitrile directly enters the IPN melter, liquid isophthalonitrile obtained by the IPN melter enters an IPN buffer tank through a conveying pump, enters an IPN vaporizer through an IPN flow meter, is fed from an upper feed inlet of the IPN vaporizer, nitrogen enters a nitrogen buffer tank, enters a nitrogen heater through the nitrogen flow meter for heating, enters the IPN vaporizer, is fed from a lower feed inlet of the IPN vaporizer, and finally gas obtained from an outlet of the IPN vaporizer is fed into a gas mixer for further mixing to obtain the mixed gas;
wherein the purity of the raw material isophthalonitrile is more than or equal to 99 percent; the heating medium of the IPN melter is heat conducting oil, and the flow rate of the heat conducting oil is controlled to be 10-100m3H; the temperature of the IPN melter is 170-240 ℃, and the IPN melter is made of stainless steel; the delivery capacity of the delivery pump is 100-1500kg/h,a pipeline filter is arranged at the inlet of the delivery pump; the temperature of the IPN buffer tank is 170-240 ℃, and the IPN buffer tank is made of stainless steel; the temperature of the IPN vaporizer is 200-330 ℃, the IPN vaporizer is made of stainless steel, and the IPN vaporizer is a vertical scraper vaporizer; controlling the purity of nitrogen to be more than or equal to 99.5 percent, controlling the pressure of the nitrogen buffer tank to be 0.3-0.6MPa, wherein the nitrogen flow meter is a volume flow meter, and the flow rate is 300-2000m3The outlet temperature of the nitrogen heater is 200-320 ℃, and the heating medium of the nitrogen heater is heat-conducting oil;
(2) preparing chlorine gas:
vaporizing liquid chlorine by a liquid chlorine vaporizer to obtain chlorine, and then sequentially passing through a chlorine buffer tank, a chlorine flowmeter and a chlorine heater to obtain the chlorine required by the process;
wherein the liquid chlorine vaporizer is heated by a water heater, and the water flow is controlled to be 10-100m3H, the temperature is 71-90 ℃, and the heat exchange area is 50-200m 2; controlling the pressure of the chlorine buffer tank to be 0.3-0.6 MPa; the chlorine flow meter is a mass flow meter; the heating medium of the chlorine heater is heat conducting oil, and the outlet temperature of the chlorine heater is controlled to be 280-350 ℃;
(3) chlorination reaction:
the mixed gas obtained in the step (1) enters from the bottom of a fluidized bed reactor through a distribution plate, the gas velocity of the mixed gas sprayed out of a gas outlet of the distribution plate is 10-20m/s, the chlorine gas obtained in the step (2) enters from the bottom of the fluidized bed reactor through a chlorine gas distributor, the gas velocity of the chlorine gas sprayed out of a gas outlet of the chlorine gas distributor is 10-20m/s, and the gas outlet of the chlorine gas distributor is over against the gas outlet of the distribution plate, so that the mixed gas and the chlorine gas flow in the reverse direction, the operation gas velocity of the fluidized bed reactor is controlled to be 0.5-4m/s, the temperature is 280-plus-350 ℃, the diameter is 2000-plus-5000 mm, and the heating medium is heat conducting oil;
wherein the molar ratio of nitrogen to isophthalonitrile in the mixed gas is (5-5.5):1, the mass ratio of chlorine to isophthalonitrile in the mixed gas is (2.4-2.5):1, the chlorine distributor is a tubular distributor, the aperture ratio is 0.75-3%, the diameter of each air hole is 5-25mm, the distance between any two adjacent air holes is 100-200mm, and the material is Monel alloy;
(4) and (3) post-treatment:
enabling the reaction gas obtained by the chlorination reaction in the step (3) to sequentially pass through a bag filter, a fixed bed filter, a trap, a tail gas filter and a tail gas processor, obtaining chlorothalonil by utilizing the trap, and discharging gas discharged from the tail gas processor at high altitude;
wherein the outlet temperature of the bag filter is 250 ℃ to 350 ℃, and the filtering area is 30-150m2The material of the filter bag is PTFE, the material of other parts is stainless steel, and the diameter is 1000-2000 mm; the diameter of the fixed bed filter is 1000-4000mm, the fixed bed filter is a tube type and is made of stainless steel, and the outlet temperature of the fixed bed filter is 200-300 ℃; the cooling mode of the trap is air cooling, the trap comprises a first trap, a second trap and a third trap which are connected in series, the temperature of the first trap is controlled to be 250-; the diameter of the tail gas filter is 1000-3000mm, and the filtering area is 10-200m2The tail gas processor absorbs hydrogen chloride by water through the falling film absorber, absorbs chlorine by the liquid alkali solution, uses process water for absorbing the hydrogen chloride as circulating water, controls the concentration of hydrochloric acid discharged by the falling film absorber to be 20-30%, controls the concentration of the liquid alkali solution to be 10-30%, and controls the spraying amount of the liquid alkali solution to be 10-80m3/h。
Compared with the prior art, the invention at least has the following beneficial effects:
the production process of chlorothalonil can reduce the mixing step before entering the reactor, avoid side reaction in the mixing process, prevent the side product from attaching to the pore plate with catalyst distributed after entering the fluidized bed, ensure the conversion rate of chlorination reaction to be always in the target level, prolong the period of shutdown and maintenance, reduce material consumption and produce high-quality chlorothalonil product with hexachlorobenzene content less than or equal to 10 ppm.
Drawings
FIG. 1 is a diagram of an apparatus corresponding to the chlorothalonil production process described in example 1 of the present invention;
FIG. 2 is a diagram of an apparatus corresponding to the process for producing chlorothalonil according to comparative example 1 of the present invention;
in the figure: 1-IPN spiral feeder; 2-IPN melter; 3-IPN buffer tank; 4-IPN vaporizer; 5-a nitrogen buffer tank; 6-nitrogen heater; 7-a gas mixer; 8-liquid chlorine vaporizer; 9-a water heater; a 10-chlorine buffer tank; 11-a chlorine gas heater; 12-a fluidized bed reactor; 13-a bag filter; 14-fixed bed filter; 15-a first trap; 16-a second trap; 17-a third trap; 18-tail gas filter.
Detailed Description
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.
To better illustrate the invention and to facilitate the understanding of the technical solutions thereof, typical but non-limiting examples of the invention are as follows:
example 1
The embodiment provides a chlorothalonil production process, an apparatus diagram corresponding to the chlorothalonil production process is shown in fig. 1, and the chlorothalonil production process comprises the following steps:
(1) preparing a mixed gas of vaporized isophthalonitrile and nitrogen:
feeding raw material isophthalonitrile into an IPN melter 2 for heating, wherein solid raw material isophthalonitrile is conveyed to the IPN melter 2 through an IPN spiral feeder 1, liquid raw material isophthalonitrile is directly fed into the IPN melter 2, liquid isophthalonitrile obtained by the IPN melter 2 is fed into an IPN buffer tank 3 through a conveying pump, then is fed into an IPN vaporizer 4 through an IPN flow meter, is fed from an upper feed inlet of the IPN vaporizer 4, nitrogen is fed into a nitrogen buffer tank 5, then is fed into a nitrogen heater 6 through the nitrogen flow meter for heating, then is fed into the IPN vaporizer 4, and is fed from a lower feed inlet of the IPN vaporizer 4, and finally, gas obtained from an outlet of the IPN vaporizer 4 is fed into a gas mixer 7 for further mixing to obtain the mixed gas;
wherein the purity of the raw material isophthalonitrile is more than or equal to 99 percent; the heating medium of the IPN melter 2 is heat conducting oil, and the flow rate is controlled to be 30m3H; the temperature of the IPN melter 2 is 200 ℃, and the material of the IPN melter 2 is stainless steel; the conveying capacity of the conveying pump is 1000kg/h, and a pipeline filter is arranged at the inlet of the conveying pump; the temperature of the IPN buffer tank 3 is 200 ℃, and the IPN buffer tank 3 is made of stainless steel; the temperature of the IPN vaporizer 4 is 250 ℃, the IPN vaporizer 4 is made of stainless steel, and the IPN vaporizer 4 is a vertical scraper vaporizer; controlling the purity of nitrogen to be more than or equal to 99.5 percent, controlling the pressure of the nitrogen buffer tank 5 to be 0.4MPa, and controlling the flow of the nitrogen to be a volume flow meter and 1000m3The outlet temperature of the nitrogen heater 6 is 250 ℃, and the heating medium of the nitrogen heater 6 is heat conduction oil;
(2) preparing chlorine gas:
the liquid chlorine is vaporized by a liquid chlorine vaporizer 8 to obtain chlorine, and then the chlorine passes through a chlorine buffer tank 10, a chlorine flow meter and a chlorine heater 11 in sequence to obtain the chlorine required by the process;
wherein the liquid chlorine vaporizer 8 adopts a water heater 9 for heating, and the water flow is controlled to be 50m3H, the temperature is 80 ℃, and the heat exchange area is 120m2(ii) a Controlling the pressure of the chlorine buffer tank 10 to be 0.5 MPa; the chlorine flow meter is a mass flow meter; the heating medium of the chlorine heater 11 is heat conducting oil, and the outlet temperature of the chlorine heater 11 is controlled to be 300 ℃;
(3) chlorination reaction:
the gas mixture obtained in the step (1) enters from the bottom of a fluidized bed reactor 12 through a distribution plate, the gas velocity of the gas mixture sprayed out from a gas outlet of the distribution plate is 15m/s, the chlorine gas obtained in the step (2) enters from the bottom of the fluidized bed reactor 12 through a chlorine gas distributor, the gas velocity of the chlorine gas sprayed out from a gas outlet of the chlorine gas distributor is 15m/s, and the gas outlet of the chlorine gas distributor is opposite to the gas outlet of the distribution plate, so that the gas mixture and the chlorine gas flow in a reverse direction, the operation gas velocity of the fluidized bed reactor 12 is controlled to be 2m/s, the temperature is 330 ℃, the diameter is 4000mm, and the heating medium is heat conducting oil;
the method comprises the following steps of (1) controlling the molar ratio of nitrogen to isophthalonitrile in the mixed gas to be 5.2:1, controlling the mass ratio of chlorine to isophthalonitrile in the mixed gas to be 2.4:1 in the fluidized bed reactor, wherein the chlorine distributor is a tubular distributor, the aperture ratio is 1.5%, the diameter of an air hole is 15mm, the distance between any two adjacent air holes is 150mm, and the material is Monel alloy;
(4) and (3) post-treatment:
enabling the reaction gas obtained by the chlorination reaction in the step (3) to sequentially pass through a bag filter 13, a fixed bed filter 14, a trap, a tail gas filter 18 and a tail gas processor, obtaining chlorothalonil by using the trap, and discharging gas discharged from the tail gas processor at high altitude;
wherein the outlet temperature of the bag filter 13 is 300 ℃, and the filtering area is 80m2The filter bag is made of PTFE, the other parts are made of stainless steel, and the diameter of the filter bag is 1500 mm; the diameter of the fixed bed filter 14 is 2000mm, the fixed bed filter 14 is in a tube type and is made of stainless steel, and the outlet temperature of the fixed bed filter 14 is 250 ℃; the cooling mode of the catcher is air cooling, the catcher comprises a first catcher 15, a second catcher 16 and a third catcher 17 which are connected in series, the temperature of the first catcher 15 is controlled to be 270 ℃, the temperature of the second catcher 16 is controlled to be 200 ℃, and the temperature of the third catcher 17 is controlled to be 120 ℃; the diameter of the tail gas filter 18 is 2000mm, and the filtering area is 100m2The tail gas processor absorbs hydrogen chloride by water through the falling film absorber, absorbs chlorine by the liquid alkali solution, uses process water for absorbing the hydrogen chloride as circulating water, controls the concentration of hydrochloric acid discharged by the falling film absorber to be 25 percent, controls the concentration of the liquid alkali solution to be 20 percent, and controls the spraying amount of the liquid alkali solution to be 50m3/h。
By adopting the chlorothalonil production process, on one hand, side reactions generated in the mixing process are effectively avoided, by-products are prevented from being attached to the pore plates distributed with the catalyst after entering the fluidized bed, the shutdown maintenance period is prolonged to 19 days, on the other hand, the unit consumption of raw materials can be further reduced, and a high-quality chlorothalonil product with hexachlorobenzene of less than or equal to 10ppm is produced.
Example 2
The embodiment provides a chlorothalonil production process, wherein a device diagram corresponding to the chlorothalonil production process is the same as that of the embodiment, and the chlorothalonil production process comprises the following steps:
(1) preparing a mixed gas of vaporized isophthalonitrile and nitrogen:
feeding raw material isophthalonitrile into an IPN melter 2 for heating, wherein solid raw material isophthalonitrile is conveyed to the IPN melter 2 through an IPN spiral feeder 1, liquid raw material isophthalonitrile is directly fed into the IPN melter 2, liquid isophthalonitrile obtained by the IPN melter 2 is fed into an IPN buffer tank 3 through a conveying pump, then is fed into an IPN vaporizer 4 through an IPN flow meter, is fed from an upper feed inlet of the IPN vaporizer 4, nitrogen is fed into a nitrogen buffer tank 5, then is fed into a nitrogen heater 6 through the nitrogen flow meter for heating, then is fed into the IPN vaporizer 4, and is fed from a lower feed inlet of the IPN vaporizer 4, and finally, gas obtained from an outlet of the IPN vaporizer 4 is fed into a gas mixer 7 for further mixing to obtain the mixed gas;
wherein the purity of the raw material isophthalonitrile is more than or equal to 99 percent; the heating medium of the IPN melter 2 is heat conducting oil, and the flow rate is controlled to be 10m3H; the temperature of the IPN melter 2 is 170 ℃, and the material of the IPN melter 2 is stainless steel; the conveying capacity of the conveying pump is 100kg/h, and a pipeline filter is arranged at the inlet of the conveying pump; the temperature of the IPN buffer tank 3 is 170 ℃, and the IPN buffer tank 3 is made of stainless steel; the temperature of the IPN vaporizer 4 is 200 ℃, the IPN vaporizer 4 is made of stainless steel, and the IPN vaporizer 4 is a vertical scraper vaporizer; controlling the purity of nitrogen to be more than or equal to 99.5 percent, controlling the pressure of the nitrogen buffer tank 5 to be 0.3MPa, wherein the nitrogen flow meter is a volume flow meter, and the flow is 300m3H, theThe outlet temperature of the nitrogen heater 6 is 200 ℃, and the heating medium of the nitrogen heater 6 is heat conduction oil;
(2) preparing chlorine gas:
the liquid chlorine is vaporized by a liquid chlorine vaporizer 8 to obtain chlorine, and then the chlorine passes through a chlorine buffer tank 10, a chlorine flow meter and a chlorine heater 11 in sequence to obtain the chlorine required by the process;
wherein the liquid chlorine vaporizer 8 is heated by a water heater 9, and the water flow is controlled to be 103H, the temperature is 71 ℃, and the heat exchange area is 50m2(ii) a Controlling the pressure of the chlorine buffer tank 10 to be 0.3 MPa; the chlorine flow meter is a mass flow meter; the heating medium of the chlorine heater 11 is heat conducting oil, and the outlet temperature of the chlorine heater 11 is controlled to be 280 ℃;
(3) chlorination reaction:
the gas mixture obtained in the step (1) enters from the bottom of a fluidized bed reactor 12 through a distribution plate, the gas velocity of the gas mixture sprayed out from a gas outlet of the distribution plate is 10m/s, the chlorine gas obtained in the step (2) enters from the bottom of the fluidized bed reactor 12 through a chlorine gas distributor, the gas velocity of the chlorine gas sprayed out from a gas outlet of the chlorine gas distributor is 10m/s, and the gas outlet of the chlorine gas distributor is over against the gas outlet of the distribution plate, so that the gas mixture and the chlorine gas flow in a reverse direction, the operation gas velocity of the fluidized bed reactor 12 is controlled to be 1m/s, the temperature is 280 ℃, the diameter is 2000mm, and the heating medium is heat conducting oil;
the method comprises the following steps of (1) controlling the molar ratio of nitrogen to isophthalonitrile in the mixed gas to be 5:1, controlling the mass ratio of chlorine to isophthalonitrile in the mixed gas to be 2.4:1 in the fluidized bed reactor, wherein the chlorine distributor is a tubular distributor, the aperture ratio is 0.72%, the diameter of each air hole is 5mm, the distance between any two adjacent air holes is 100mm, and the material is Monel alloy;
(4) and (3) post-treatment:
enabling the reaction gas obtained by the chlorination reaction in the step (3) to sequentially pass through a bag filter 13, a fixed bed filter 14, a trap, a tail gas filter 18 and a tail gas processor, obtaining chlorothalonil by using the trap, and discharging gas discharged from the tail gas processor at high altitude;
wherein the outlet temperature of the bag filter 13 is 250 ℃, and the filtering area is 30m2The filter bag is made of PTFE, the other parts of the filter bag are made of stainless steel, and the diameter of the filter bag is 1000 mm; the diameter of the fixed bed filter 14 is 1000mm, the fixed bed filter 14 is in a tube type and is made of stainless steel, and the outlet temperature of the fixed bed filter 14 is 200 ℃; the cooling mode of the catcher is air cooling, the catcher comprises a first catcher 15, a second catcher 16 and a third catcher 17 which are connected in series, the temperature of the first catcher 15 is controlled to be 250 ℃, the temperature of the second catcher 16 is controlled to be 150 ℃, and the temperature of the third catcher 17 is controlled to be 100 ℃; the diameter of the tail gas filter 18 is 1000mm, and the filtering area is 10m2The tail gas processor absorbs hydrogen chloride by water through the falling film absorber, absorbs chlorine by the liquid alkali solution, uses process water for absorbing the hydrogen chloride as circulating water, controls the concentration of hydrochloric acid discharged by the falling film absorber to be 20 percent, controls the concentration of the liquid alkali solution to be 10 percent, and controls the spraying amount of the liquid alkali solution to be 10m3/h。
By adopting the chlorothalonil production process, on one hand, side reactions generated in the mixing process are effectively avoided, by-products are prevented from being attached to the pore plates distributed with the catalyst after entering the fluidized bed, the shutdown maintenance period is prolonged to 16 days, on the other hand, the unit consumption of raw materials can be further reduced, and a high-quality chlorothalonil product with hexachlorobenzene of less than or equal to 10ppm is produced.
Example 3
The embodiment provides a chlorothalonil production process, the apparatus diagram corresponding to the chlorothalonil production process is the same as that in embodiment 1, and the chlorothalonil production process comprises the following steps:
(1) preparing a mixed gas of vaporized isophthalonitrile and nitrogen:
feeding raw material isophthalonitrile into an IPN melter 2 for heating, wherein solid raw material isophthalonitrile is conveyed to the IPN melter 2 through an IPN spiral feeder 1, liquid raw material isophthalonitrile is directly fed into the IPN melter 2, liquid isophthalonitrile obtained by the IPN melter 2 is fed into an IPN buffer tank 3 through a conveying pump, then is fed into an IPN vaporizer 4 through an IPN flow meter, is fed from an upper feed inlet of the IPN vaporizer 4, nitrogen is fed into a nitrogen buffer tank 5, then is fed into a nitrogen heater 6 through the nitrogen flow meter for heating, then is fed into the IPN vaporizer 4, and is fed from a lower feed inlet of the IPN vaporizer 4, and finally, gas obtained from an outlet of the IPN vaporizer 4 is fed into a gas mixer 7 for further mixing to obtain the mixed gas;
wherein the purity of the raw material isophthalonitrile is more than or equal to 99 percent; the heating medium of the IPN melter 2 is heat conducting oil, and the flow rate is controlled to be 100m3H; the temperature of the IPN melter 2 is 240 ℃, and the material of the IPN melter 2 is stainless steel; the conveying capacity of the conveying pump is 1500kg/h, and a pipeline filter is arranged at the inlet of the conveying pump; the temperature of the IPN buffer tank 3 is 240 ℃, and the IPN buffer tank 3 is made of stainless steel; the temperature of the IPN vaporizer 4 is 330 ℃, the IPN vaporizer 4 is made of stainless steel, and the IPN vaporizer 4 is a vertical scraper vaporizer; controlling the purity of the nitrogen to be more than or equal to 99.5 percent, controlling the pressure of the nitrogen buffer tank 5 to be 0.6MPa, and controlling the flow of the nitrogen to be a volume flow meter and 2000m3The outlet temperature of the nitrogen heater 6 is 320 ℃, and the heating medium of the nitrogen heater 6 is heat conducting oil;
(2) preparing chlorine gas:
the liquid chlorine is vaporized by a liquid chlorine vaporizer 8 to obtain chlorine, and then the chlorine passes through a chlorine buffer tank 10, a chlorine flow meter and a chlorine heater 11 in sequence to obtain the chlorine required by the process;
wherein the liquid chlorine vaporizer 8 adopts a water heater 9 for heating, and the water flow is controlled to be 100m3H, the temperature is 90 ℃, and the heat exchange area is 200m2(ii) a Controlling the pressure of the chlorine buffer tank 10 to be 0.6 MPa; the chlorine flow meter is a mass flow meter; the heating medium of the chlorine heater 11 is heat conducting oil, and the outlet temperature of the chlorine heater 11 is controlled to be 350 ℃;
(3) chlorination reaction:
the gas mixture obtained in the step (1) enters from the bottom of a fluidized bed reactor 12 through a distribution plate, the gas velocity of the gas mixture sprayed out from a gas outlet of the distribution plate is 20m/s, the chlorine gas obtained in the step (2) enters from the bottom of the fluidized bed reactor 12 through a chlorine gas distributor, the gas velocity of the chlorine gas sprayed out from a gas outlet of the chlorine gas distributor is 20m/s, the gas outlet of the chlorine gas distributor is opposite to the gas outlet of the distribution plate, the gas mixture and the chlorine gas flow in a reverse direction, the operation gas velocity of the fluidized bed reactor 12 is controlled to be 4m/s, the temperature is 350 ℃, the diameter is 5000mm, and the heating medium is heat conducting oil;
the method comprises the following steps of (1) controlling the molar ratio of nitrogen to isophthalonitrile in the mixed gas to be 5.5:1, controlling the mass ratio of chlorine to isophthalonitrile in the mixed gas to be 2.5:1 in the fluidized bed reactor, wherein the chlorine distributor is a tubular distributor, the aperture ratio is 3%, the diameter of each air hole is 25mm, the distance between any two adjacent air holes is 200mm, and the material is Monel alloy;
(4) and (3) post-treatment:
enabling the reaction gas obtained by the chlorination reaction in the step (3) to sequentially pass through a bag filter 13, a fixed bed filter 14, a trap, a tail gas filter 18 and a tail gas processor, obtaining chlorothalonil by using the trap, and discharging gas discharged from the tail gas processor at high altitude;
wherein the outlet temperature of the bag filter 13 is 350 ℃, and the filtering area is 150m2The filter bag is made of PTFE, and the other parts of the filter bag are made of stainless steel with the diameter of 2000 mm; the diameter of the fixed bed filter 14 is 4000mm, the fixed bed filter 14 is in a tube type and is made of stainless steel, and the outlet temperature of the fixed bed filter 14 is 300 ℃; the cooling mode of the catcher is air cooling, the catcher comprises a first catcher 15, a second catcher 16 and a third catcher 17 which are connected in series, the temperature of the first catcher 15 is controlled to be 300 ℃, the temperature of the second catcher 16 is controlled to be 250 ℃, and the temperature of the third catcher 17 is controlled to be 150 ℃; the diameter of the tail gas filter 18 is 3000mm, and the filtering area is 200m2The tail gas processor absorbs hydrogen chloride by water through the falling film absorber and absorbs hydrogen chloride by liquid alkali solutionChlorine is collected, process water for absorbing hydrogen chloride is circulating water, the concentration of hydrochloric acid discharged by the falling film absorber is controlled to be 30%, the concentration of the liquid alkali solution is controlled to be 30%, and the spraying amount of the liquid alkali solution is controlled to be 80m3/h。
By adopting the chlorothalonil production process, on one hand, side reactions generated in the mixing process are effectively avoided, by-products are prevented from being attached to the pore plates distributed with the catalyst after entering the fluidized bed, the shutdown maintenance period is prolonged to 17 days, on the other hand, the unit consumption of raw materials can be further reduced, and a high-quality chlorothalonil product with hexachlorobenzene of less than or equal to 10ppm is produced.
Comparative example 1
This comparative example provides a process for producing chlorothalonil, which corresponds to an apparatus diagram shown in fig. 2, except that chlorine gas obtained in step (2) is introduced into a gas mixer 7 and is uniformly mixed with the gas mixture obtained in step (1), and then the gas obtained from the gas mixer 7 is introduced from the bottom of a fluidized bed reactor 12 through a distribution plate, and accordingly, a chlorine gas distributor is omitted, and the other conditions are exactly the same as those in example 1.
By adopting the chlorothalonil production process of the comparative example, complex side reactions can occur in the mixing process of the gas mixer 7, and generated byproducts can be attached to the pore plates distributed with the catalyst after entering the fluidized bed, so that the conversion rate of chlorination reaction is gradually reduced, and the shutdown and overhaul period is shortened to 12 days.
In conclusion, the chlorothalonil production process disclosed by the invention can reduce the mixing step before entering the reactor, avoid side reactions in the mixing process, further prevent byproducts from attaching to the pore plates distributed with the catalyst after entering the fluidized bed, effectively ensure that the conversion rate of chlorination reaction is always at a target level, prolong the shutdown and maintenance period, further reduce the unit consumption of raw materials and produce high-quality chlorothalonil products with hexachlorobenzene of less than or equal to 10 ppm.
The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must be implemented depending on the above detailed structural features. It should be understood by those skilled in the art that any modifications of the present invention, equivalent substitutions of selected components of the present invention, additions of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims (10)

1. A production process of chlorothalonil is characterized in that vaporized isophthalonitrile is mixed with nitrogen to obtain mixed gas, then the mixed gas and chlorine are respectively introduced into a reactor to carry out chlorination reaction, and reaction gas obtained by the chlorination reaction is subjected to post-treatment to obtain the chlorothalonil.
2. The chlorothalonil production process according to claim 1, wherein the method of preparing the gas mixture comprises the steps of:
and feeding the raw material isophthalonitrile into an IPN melter for heating, feeding the obtained liquid isophthalonitrile into an IPN vaporizer through an IPN flowmeter, feeding from an upper feeding port of the IPN vaporizer, feeding nitrogen into the IPN vaporizer through a nitrogen flowmeter, feeding from a lower feeding port of the IPN vaporizer, and feeding the gas obtained from an outlet of the IPN vaporizer into a gas mixer for further mixing to obtain the mixed gas.
3. A chlorothalonil production process according to claim 2, wherein the raw material isophthalonitrile is in a liquid and/or solid state;
preferably, the solid raw material isophthalonitrile is conveyed to the IPN melter through an IPN spiral feeder, and the liquid raw material isophthalonitrile is directly fed into the IPN melter;
preferably, the purity of the raw material isophthalonitrile is more than or equal to 99 percent;
preferably, an IPN buffer tank is arranged between the IPN melter and the IPN flowmeter, and the liquid isophthalonitrile obtained by the IPN melter enters the IPN buffer tank through a delivery pump;
preferably, the heating medium of the IPN melter comprises any one or a combination of at least two of a heat transfer oil, a molten salt or superheated steam, preferably a heat transfer oil;
preferably, the flow rate of the heat conducting oil in the IPN melter is 10-100m3/h；
Preferably, the temperature of the IPN melter is 170-240 ℃.
4. The chlorothalonil production process according to claim 2 or 3, wherein the delivery volume of the delivery pump is 1500 kg/h;
preferably, a pipeline filter is arranged at an inlet of the delivery pump;
preferably, the temperature of the IPN buffer tank is 170-240 ℃;
preferably, the temperature of the IPN vaporizer is 200-330 ℃.
5. A chlorothalonil production process according to any one of claims 2-4, wherein nitrogen is fed into a nitrogen buffer tank, passed through the nitrogen flow meter, fed into a nitrogen heater for heating, and then fed into the IPN vaporizer;
preferably, the purity of the nitrogen is more than or equal to 99.5 percent;
preferably, the flow rate of the nitrogen gas flowmeter is 300-2000m3/h；
Preferably, the pressure of the nitrogen buffer tank is 0.3-0.6 MPa;
preferably, the outlet temperature of the nitrogen heater is 200-320 ℃.
6. The chlorothalonil production process according to any one of claims 1 to 5, wherein liquid chlorine is vaporized by a liquid chlorine vaporizer to obtain chlorine gas, and the chlorine gas passes through a chlorine gas buffer tank, a chlorine gas flowmeter and a chlorine gas heater in sequence and then enters the reactor;
preferably, the liquid chlorine vaporizer is heated by a water heater;
preferably, the water flow rate of the water heater is 10-100m3/h；
Preferably, the temperature of the liquid chlorine vaporizer is 71-90 ℃;
preferably, the heat exchange area of the liquid chlorine vaporizer is 50-200m2；
Preferably, the pressure of the chlorine buffer tank is 0.3-0.6 MPa;
preferably, the outlet temperature of the chlorine heater is 280-350 ℃.
7. The chlorothalonil production process according to any one of claims 1 to 6 wherein the mixture enters from the bottom of the reactor through a distribution plate, the chlorine enters from the bottom of the reactor through a chlorine distributor, and the outlets of the chlorine distributor are opposite to the outlets of the distribution plate, such that the mixture flows counter-currently to the chlorine;
preferably, the reactor is operated at a gas velocity of 0.5 to 4m/s, preferably 1 to 2 m/s;
preferably, the gas velocity of the mixed gas sprayed from the gas outlet of the distribution plate is 10-20 m/s;
preferably, the gas speed of the chlorine sprayed from the gas outlet of the chlorine distributor is 10-20 m/s;
preferably, the molar ratio of the nitrogen to the isophthalonitrile in the mixed gas is (5-5.5) to 1;
preferably, in the reactor, the mass ratio of the chlorine gas to the mixed gas intermediate phthalonitrile is controlled to be (2.4-2.5): 1;
preferably, the chlorine distributor comprises a pipe distributor, a nozzle distributor, a plate distributor, preferably a pipe distributor;
preferably, the diameter of the air hole of the chlorine distributor is 5-25mm, and the distance between any two adjacent air holes is 100-200 mm;
preferably, the open pore rate of the chlorine distributor is 0.75-3%, preferably 1-2%;
preferably, the chlorine gas distributor material comprises any one or a combination of at least two of carbon steel, stainless steel, hastelloy, a nickel alloy, or monel, preferably monel.
8. A chlorothalonil production process according to any of claims 1-7, wherein the reactor is a fluidized bed reactor;
preferably, the temperature of the fluidized bed reactor is 280-350 ℃;
preferably, the diameter of the fluidized bed reactor is 2000-.
9. A chlorothalonil production process according to any of claims 1-8, wherein the post-treatment comprises: enabling the reaction gas obtained by chlorination to sequentially pass through a bag filter, a fixed bed filter, a trap, a tail gas filter and a tail gas processor, obtaining chlorothalonil by using the trap, and discharging gas discharged from the tail gas processor at high altitude;
preferably, the outlet temperature of the bag filter is 250-350 ℃;
preferably, the filtration area of the bag filter is 30-150m2；
Preferably, the diameter of the bag filter is 1000-;
preferably, the diameter of the fixed bed filter is 1000-4000 mm;
preferably, the outlet temperature of the fixed bed filter is 200-300 ℃;
preferably, the cooling mode of the catcher comprises air cooling, water cooling or oil cooling, and preferably air cooling;
preferably, the trap comprises a first trap, a second trap and a third trap connected in series;
preferably, the temperature of the first trap is 250-300 ℃;
preferably, the temperature of the second trap is 150-250 ℃;
preferably, the temperature of the third trap is 100-150 ℃;
preferably, the diameter of the tail gas filter is 1000-3000 mm;
preferably, the filtering area of the tail gas filter is 10-200m2；
Preferably, the tail gas processor absorbs hydrogen chloride by using water through a falling film absorber, and absorbs chlorine by using a liquid alkali solution;
preferably, the process water for absorbing the hydrogen chloride comprises any one of deep well water, circulating water or soft water or a combination of at least two of the deep well water, the circulating water and the soft water, and is preferably the circulating water;
preferably, the concentration of hydrochloric acid discharged from the falling film absorber is controlled to be 20-30%;
preferably, the concentration of the liquid caustic soda solution is controlled to be 10-30%;
preferably, the spraying amount of the liquid alkali solution is controlled to be 10-80m3/h。
10. A chlorothalonil production process according to any one of claims 1-9, comprising the steps of:
(1) preparing a mixed gas of vaporized isophthalonitrile and nitrogen:
feeding raw material isophthalonitrile into an IPN melter for heating, wherein solid raw material isophthalonitrile is conveyed to the IPN melter through an IPN spiral feeder, liquid raw material isophthalonitrile directly enters the IPN melter, liquid isophthalonitrile obtained by the IPN melter enters an IPN buffer tank through a conveying pump, enters an IPN vaporizer through an IPN flow meter, is fed from an upper feed inlet of the IPN vaporizer, nitrogen enters a nitrogen buffer tank, enters a nitrogen heater through the nitrogen flow meter for heating, enters the IPN vaporizer, is fed from a lower feed inlet of the IPN vaporizer, and finally gas obtained from an outlet of the IPN vaporizer is fed into a gas mixer for further mixing to obtain the mixed gas;
wherein the purity of the raw material isophthalonitrile is more than or equal to 99 percent; the heating medium of the IPN melter is heat conducting oil, and the flow rate of the heat conducting oil is controlled to be 10-100m3H; the temperature of the IPN melter is 170-240 ℃, and the IPN melter is made of stainless steel; the delivery capacity of the delivery pump is 100-1500kg/h, and a pipeline filter is arranged at the inlet of the delivery pump; the temperature of the IPN buffer tank is 170-240 ℃, and the IPN buffer tank is made of stainless steel; the temperature of the IPN vaporizer is 200-330 ℃, the IPN vaporizer is made of stainless steel, and the IPN vaporizer is a vertical scraper vaporizer; controlling the purity of nitrogen to be more than or equal to 99.5 percent, controlling the pressure of the nitrogen buffer tank to be 0.3-0.6MPa, wherein the nitrogen flow meter is a volume flow meter, and the flow rate is 300-2000m3The outlet temperature of the nitrogen heater is 200-320 ℃, and the heating medium of the nitrogen heater is heat-conducting oil;
(2) preparing chlorine gas:
vaporizing liquid chlorine by a liquid chlorine vaporizer to obtain chlorine, and then sequentially passing through a chlorine buffer tank, a chlorine flowmeter and a chlorine heater to obtain the chlorine required by the process;
wherein the liquid chlorine vaporizer is heated by a water heater, and the water flow is controlled to be 10-100m3H, the temperature is 71-90 ℃, and the heat exchange area is 50-200m2(ii) a Controlling the pressure of the chlorine buffer tank to be 0.3-0.6 MPa; the chlorine flow meter is a mass flow meter; the heating medium of the chlorine heater is heat conducting oil, and the outlet temperature of the chlorine heater is controlled to be 280-350 ℃;
(3) chlorination reaction:
the mixed gas obtained in the step (1) enters from the bottom of a fluidized bed reactor through a distribution plate, the gas velocity of the mixed gas sprayed out of a gas outlet of the distribution plate is 10-20m/s, the chlorine gas obtained in the step (2) enters from the bottom of the fluidized bed reactor through a chlorine gas distributor, the gas velocity of the chlorine gas sprayed out of a gas outlet of the chlorine gas distributor is 10-20m/s, and the gas outlet of the chlorine gas distributor is over against the gas outlet of the distribution plate, so that the mixed gas and the chlorine gas flow in the reverse direction, the operation gas velocity of the fluidized bed reactor is controlled to be 0.5-4m/s, the temperature is 280-plus-350 ℃, the diameter is 2000-plus-5000 mm, and the heating medium is heat conducting oil;
wherein the molar ratio of nitrogen to isophthalonitrile in the mixed gas is (5-5.5):1, the mass ratio of chlorine to isophthalonitrile in the mixed gas is (2.4-2.5):1, the chlorine distributor is a tubular distributor, the aperture ratio is 0.75-3%, the diameter of each air hole is 5-25mm, the distance between any two adjacent air holes is 100-200mm, and the material is Monel alloy;
(4) and (3) post-treatment:
enabling the reaction gas obtained by the chlorination reaction in the step (3) to sequentially pass through a bag filter, a fixed bed filter, a trap, a tail gas filter and a tail gas processor, obtaining chlorothalonil by utilizing the trap, and discharging gas discharged from the tail gas processor at high altitude;
wherein the outlet temperature of the bag filter is 250 ℃ to 350 ℃, and the filtering area is 30-150m2The material of the filter bag is PTFE, the material of other parts is stainless steel, and the diameter is 1000-2000 mm; the diameter of the fixed bed filter is 1000-4000mm, the fixed bed filter is a tube type and is made of stainless steel, and the outlet temperature of the fixed bed filter is 200-300 ℃; the cooling mode of the trap is air cooling, the trap comprises a first trap, a second trap and a third trap which are connected in series, the temperature of the first trap is controlled to be 250-; the diameter of the tail gas filter is 1000-3000mm, and the filtering area is 10-200m2The tail gas processor absorbs hydrogen chloride by utilizing water through the falling film absorber and chlorine by utilizing a liquid alkali solution for absorbing chlorineThe process water of the hydrogen chemical is circulating water, the concentration of hydrochloric acid discharged by the falling film absorber is controlled to be 20-30%, the concentration of the liquid alkali solution is controlled to be 10-30%, and the spraying amount of the liquid alkali solution is controlled to be 10-80m3/h。
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