阅读说明：本技术 一种用于四氯间苯二甲腈反应气的捕集方法及捕集系统 (Trapping method and trapping system for tetrachloroisophthalonitrile reaction gas ) 是由 禚文峰 顾林健 潘修伟 王晴 于 2020-07-17 设计创作，主要内容包括：本发明提供了一种用于四氯间苯二甲腈反应气的捕集方法及捕集系统,所述的捕集方法包括：上游产线输送的反应气过滤后进入多级捕集单元,在多级捕集单元中与液氮经过至少两次混合,反应气与液氮混合后凝华,捕集析出其中的四氯间苯二甲腈。本发明使用液氮作为捕集装置的冷却介质,液氮通过分布器进入捕集装置直接汽化,反应气中的四氯间苯二甲腈气体与液氮接触直接凝华析出四氯间苯二甲腈至捕集装置底部,经过输送机进入产品料仓,将传统的风冷或水冷方式替换为液氮冷却,有效避免了传统捕集工艺使用夹套冷却介质冷却反应气导致物料结壁和塌料现象,从而有效解决了捕集装置底部排料口堵塞,影响正常生产的技术问题。(The invention provides a method and a system for trapping tetrachloroisophthalonitrile reaction gas, wherein the trapping method comprises the following steps: and filtering the reaction gas conveyed by the upstream production line, then feeding the reaction gas into a multistage trapping unit, mixing the reaction gas with liquid nitrogen at least twice in the multistage trapping unit, and sublimating the reaction gas after mixing with the liquid nitrogen to trap and separate out tetrachloroisophthalonitrile in the reaction gas. According to the invention, liquid nitrogen is used as a cooling medium of the trapping device, the liquid nitrogen enters the trapping device through the distributor to be directly vaporized, tetrachloroisophthalonitrile gas in reaction gas is contacted with the liquid nitrogen to be directly desublimated and separated out to the bottom of the trapping device, and the tetrachloroisophthalonitrile gas enters the product bin through the conveyor, so that the traditional air cooling or water cooling mode is replaced by liquid nitrogen cooling, the phenomena of material wall formation and material collapse caused by cooling of the reaction gas by using a jacket cooling medium in the traditional trapping process are effectively avoided, and the technical problem that the normal production is influenced due to the blockage of a discharge port at the bottom of the trapping device is effectively solved.)

1. A method for collecting tetrachloroisophthalonitrile reaction gas, which is characterized by comprising the following steps:

and filtering the reaction gas conveyed by the upstream production line, then feeding the reaction gas into a multistage trapping unit, mixing the reaction gas with liquid nitrogen at least twice in the multistage trapping unit, and sublimating the reaction gas after mixing with the liquid nitrogen to trap and separate out tetrachloroisophthalonitrile in the reaction gas.

2. The trapping method according to claim 1, characterized in that the trapping method specifically comprises:

reaction gas conveyed by an upstream production line is filtered by a bag type filtering device and then is introduced into a fixed bed filtering device through a heat preservation pipe;

(II) the reaction gas discharged by the fixed bed filtering device sequentially flows through a first trapping device and a second trapping device, is respectively mixed with liquid nitrogen in the first trapping device and the second trapping device, and is desublimated after being mixed with the liquid nitrogen, and tetrachloroisophthalonitrile separated out of the reaction gas is trapped;

(III) introducing the tail gas discharged by the second trapping device into a tail gas filtering device, wherein the filtered tail gas is divided into two parts, one part is recycled to the first trapping device, and the other part is discharged after tail gas treatment.

3. The trapping method according to claim 2, wherein in step (i), a jacket is arranged outside the heat-insulating pipe, and a heat-conducting medium is introduced into the jacket;

preferably, the heat conducting medium is heat conducting oil;

preferably, the heat conduction oil is low-temperature heat conduction oil, medium-temperature heat conduction oil or high-temperature heat conduction oil, and further preferably, the heat conduction oil is high-temperature heat conduction oil;

preferably, the temperature of the heat-conducting medium is 330-350 ℃;

preferably, the temperature in the heat preservation pipe is controlled by adjusting the flow of the heat-conducting medium in the jacket;

preferably, automatic interlocking control is carried out between the temperature in the heat preservation pipe and the flow of the heat-conducting medium;

preferably, the flow rate of the heat-conducting medium is 20-30 m³H, further preferably, the flow rate of the heat-conducting medium is 25m³/h；

Preferably, the temperature in the heat preservation pipe is controlled to be 320-340 ℃.

4. The capturing method according to claim 2 or 3, characterized in that in the step (II), the liquid nitrogen is respectively and independently introduced into the first capturing device and the second capturing device through a uniform distribution device;

preferably, the trapping temperatures in the first trapping device and the second trapping device are respectively controlled by independently adjusting the flow rate of the liquid nitrogen;

preferably, automatic interlocking control is carried out between the trapping temperature and the liquid nitrogen flow rate in the first trapping device and the second trapping device;

preferably, the flow of liquid nitrogen introduced into the first trapping device is 75-200 kg/h;

preferably, the collection temperature in the first collection device is controlled to be 140-180 ℃, and further preferably, the collection temperature in the first collection device is controlled to be 150-170 ℃;

preferably, the flow of the liquid nitrogen introduced into the second trapping device is 20-45 kg/h;

preferably, the collection temperature in the second collection device is controlled to be 100-140 ℃, and further preferably, the collection temperature in the second collection device is 110-130 ℃;

preferably, the collection efficiency of the first collection device is 70-90%;

preferably, the collection efficiency of the second collection device is 5-25%;

preferably, the content of the liquid nitrogen is 99-99.9%, and further preferably, the content of the liquid nitrogen is 99.9%;

preferably, the tetrachloroisophthalonitrile captured by the first capture device and the tetrachloroisophthalonitrile captured by the second capture device are respectively led into a product conveying system.

5. The capturing method according to any one of claims 2 to 4, wherein in the step (III), a jacket is arranged outside the tail gas filtering device, and a cooling medium is introduced into the jacket;

preferably, the cooling medium is circulating water or frozen brine, and further preferably, the cooling medium is circulating water;

preferably, the temperature of the cooling medium is 10-20 ℃;

preferably, the temperature in the exhaust gas filtering device is controlled by adjusting the flow rate of the cooling medium in the jacket;

preferably, automatic interlocking control is carried out between the temperature in the tail gas filtering device and the flow of the cooling medium;

preferably, the flow of the cooling medium is 10-15 m³/h；

Preferably, the temperature in the tail gas filtering device is controlled to be 50-80 ℃, and further preferably, the temperature of the tail gas filtering device is controlled to be 60-70 ℃;

preferably, the tail gas discharged by the second trapping device is filtered to remove solid waste in the tail gas by a tail gas filtering device, the tail gas after solid waste removal is filtered is divided into a first tail gas and a second tail gas according to the volume ratio, and the volume ratio of the first tail gas to the second tail gas is 0.11-0.25;

preferably, the first tail gas is returned to the first trapping device through a fan, and the cold energy in the first tail gas is circularly applied in the first trapping device;

preferably, the air volume of the fan is 150-300 m³H, further preferably, the air volume of the fan is 300m³/h；

Preferably, the second tail gas is treated by the tail gas treatment device and then is led out and discharged by an exhaust fan;

preferably, the flow of the exhaust fan is 5000-10000 m³H, further preferably, the flow of the exhaust fan is 10000m³/h；

Preferably, the air pressure of the exhaust fan is 1000-2500 Pa, and further preferably, the air pressure of the exhaust fan is 2000 Pa.

6. A capturing system for tetrachloroisophthalonitrile reaction gas, characterized in that the capturing system is used for carrying out the capturing method according to any one of claims 1 to 5, and comprises a filtering unit and a multistage capturing unit which are connected;

the multistage trapping unit comprises at least two trapping devices which are connected in sequence, and the trapping devices are respectively connected with a liquid nitrogen supply device.

7. The capture system of claim 6, wherein the filtration unit comprises a bag filtration device and a fixed bed filtration device connected in series;

preferably, the bag type filtering device and the fixed bed filtering device are connected through a heat preservation pipe;

preferably, the outer side of the heat preservation pipe is provided with a jacket, and a heat-conducting medium is introduced into the jacket;

preferably, the heat conducting medium is heat conducting oil;

preferably, a reaction gas temperature sensor is arranged in the heat preservation pipe, a heat-conducting medium flow control valve is arranged on a jacket liquid inlet pipeline of the heat preservation pipe, the reaction gas temperature sensor is connected with the reaction gas flow control valve in a feedback mode, and the opening degree of the heat-conducting medium flow control valve is controlled in real time through the reaction gas temperature in the pipe detected by the reaction gas temperature sensor.

8. The trapping system according to claim 6 or 7, characterized in that a uniform distribution device is arranged at the air inlet of the trapping device;

preferably, the product outlets of the trapping devices are respectively connected with a product conveying system;

preferably, the multistage trapping unit comprises a first trapping device and a second trapping device which are connected in sequence, and the first trapping device and the second trapping device are respectively connected with a liquid nitrogen supply device;

preferably, a first electric control valve is arranged on a connecting pipeline between the first trapping device and the liquid nitrogen supply device, and a second electric control valve is arranged on a connecting pipeline between the first trapping device and the liquid nitrogen supply device;

preferably, a first temperature sensing device and a second temperature sensing device are respectively arranged in the first trapping device and the second trapping device, the first temperature sensing device is connected with the first electric control valve in a feedback mode, and the second temperature sensing device is connected with the second electric control valve in a feedback mode.

9. The capture system of any one of claims 6 to 8, wherein the capture system further comprises a tail gas filtering device and a tail gas treatment device which are sequentially connected with the outlets of the multistage capture units;

preferably, a jacket is arranged on the outer side of the tail gas filtering device, and a cooling medium is introduced into the jacket;

preferably, the cooling medium is circulating water or frozen brine, and further preferably, the cooling medium is circulating water;

preferably, a tail gas temperature sensor is arranged in the tail gas filtering device, a cooling medium flow control valve is arranged on a jacket liquid inlet pipeline of the tail gas filtering device, the tail gas temperature sensor is connected with the cooling medium flow control valve in a feedback mode, and the opening degree of the cooling medium flow control valve is controlled in real time through the tail gas temperature detected by the tail gas temperature sensor;

preferably, the tail gas outlet of the tail gas filtering device is divided into two paths, one path is connected with the first trapping device in a returning mode, and the other path is connected with a downstream tail gas treatment device.

10. The capture system according to any one of claims 6 to 9, wherein a fan is arranged on a connecting pipeline between the tail gas filtering device and the first capture device;

preferably, the fan is made of steel lining PTFE or glass fiber reinforced plastic, and further preferably, the fan is made of glass fiber reinforced plastic;

preferably, the exhaust port of the tail gas treatment device is provided with an induced draft fan.

Technical Field

The invention belongs to the technical field of product trapping, relates to a trapping method and a trapping system, and particularly relates to a trapping method and a trapping system for tetrachloroisophthalonitrile reaction gas.

Background

Tetrachloroisophthalonitrile, also called chlorothalonil, is a high-efficiency, low-toxicity and broad-spectrum protective bactericide which is mainly used for preventing and treating various fungal diseases, and the action mechanism of the tetrachloroisophthalonitrile is that the tetrachloroisophthalonitrile can act with glyceraldehyde triphosphate dehydrogenase in fungal cells and is combined with protein containing cysteine in the enzyme, so that the activity of the enzyme is damaged, and the metabolism of the fungal cells is damaged to lose the vitality. Chlorothalonil has no internal absorption and conduction effects, but has good adhesion on the body surface after being sprayed on plants, and is not easy to be washed away by rainwater, so the pesticide effect period is longer. Is mainly used for preventing and treating rust disease, anthracnose, powdery mildew and downy mildew on fruit trees and vegetables. The bactericidal composition is mainly used for preventing rust disease, anthracnose, powdery mildew and downy mildew on fruit trees and vegetables and preventing plants from being damaged by fungi. Tetrachloroisophthalonitrile is also used abroad for sterilization of golf courses, lawns and ornamental plants, and for preservative treatment of some trees and paintings.

The simplest and most economical manufacturing process of tetrachloroisophthalonitrile is as follows: the isophthalonitrile is melted and then sent into a vaporizer to be vaporized or directly atomized with a part of gas flow through a nozzle to be subjected to a reactor. Chlorine gas is mixed with gaseous isophthalonitrile after being dried and preheated, and nitrogen is used as diluent gas for vaporization or atomization of isophthalonitrile and adjustment of reactant concentration. The reactor adopts a fluidized bed or other forms, gas after reaction enters a catcher, chlorothalonil is desublimated and separated out and is continuously sent out to obtain the product, and the yield is 90%. The tail gas is mainly chlorine, hydrogen chloride and nitrogen, and can be partially circulated or completely removed from a tail gas recovery treatment system. Liquid carbon tetrachloride can be sprayed into the catcher, and after the liquid carbon tetrachloride is contacted with the reaction gas, chlorothalonil is sublimated and separated out. The carbon tetrachloride is vaporized and discharged together with the tail gas, and is further cooled to-6 ℃, and the carbon tetrachloride is condensed for recycling.

The indirect cooling type trapping is also called square box type trapping, and is a commonly used trapping mode for domestic small tetrachloroisophthalonitrile manufacturers at present. The mixed reaction gas out of the fluidized bed reactor enters a fixed bed for further reaction after being filtered by a filter, then enters a people square box type trap through a jacket heat-conducting oil heat-preserving pipe, the trap is provided with an outer jacket and cools the mixed reaction gas through circulating cooling water, a crystallized material is desublimated and freely settled in the trap, tetrachloroisophthalonitrile is conveyed to a crushing device through a product conveying system, and a finished product tetrachloroisophthalonitrile is obtained after crushing. Because the desublimation and crystallization process of tetrachloroisophthalonitrile is not a constant temperature process, and the trapping of all materials cannot be completed in one trap generally, the operation needs to be carried out in a mode of connecting a plurality of square boxes in series. At present, the most used plants are operated in series by boxes until the content of the tetrachloroisophthalonitrile remaining in the mixed reaction gas reaches the lower economic limit of recovery. The induced draft fan is established to the tail gas processing apparatus export, guarantees that whole entrapment system can not lead to revealing of poisonous and harmful reaction gas during the ejection of compact at little negative pressure state.

However, most of the existing trapping devices adopt air cooling or water cooling as a cooling medium, and the cooling medium needs to flow in a jacket, so that the blocking of a discharge port at the bottom of the trapping device due to the phenomena of material wall bonding and material collapse is easily caused, and the normal trapping operation is influenced.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a trapping method and a trapping system for tetrachloroisophthalonitrile reaction gas, wherein liquid nitrogen is used as a cooling medium of a trapping device, the liquid nitrogen enters the trapping device through a distributor to be directly vaporized, the tetrachloroisophthalonitrile gas in the reaction gas is contacted with the liquid nitrogen to be directly desublimated and separated out tetrachloroisophthalonitrile to the bottom of the trapping device, and the tetrachloroisophthalonitrile gas enters a product bin through a conveyor, the traditional air-cooling or water-cooling indirect trapping mode is replaced by the liquid nitrogen direct-contact trapping, so that the phenomena of wall bonding and material collapse caused by cooling, crystallization and separation of the reaction gas on the inner wall of the trapping device due to small heat exchange area and large local temperature difference of a jacket cooling medium used in the traditional trapping process are effectively avoided, thereby effectively solving the technical problem that the discharge hole at the bottom of the trapping device is blocked to influence the normal production.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a method for capturing tetrachloroisophthalonitrile reaction gas, the method comprising:

and filtering the reaction gas conveyed by the upstream production line, then feeding the reaction gas into a multistage trapping unit, mixing the reaction gas with liquid nitrogen at least twice in the multistage trapping unit, and sublimating the reaction gas after mixing with the liquid nitrogen to trap and separate out tetrachloroisophthalonitrile in the reaction gas.

According to the invention, liquid nitrogen is used as a cooling medium of the trapping device, the liquid nitrogen enters the trapping device through the distributor to be directly vaporized, tetrachloroisophthalonitrile gas in reaction gas is contacted with the liquid nitrogen to be directly desublimated and separated out to the bottom of the trapping device, and the tetrachloroisophthalonitrile gas enters the product bin through the conveyor, so that the traditional air cooling or water cooling mode is replaced by liquid nitrogen cooling, the phenomena of material wall formation and material collapse caused by cooling of the reaction gas by using a jacket cooling medium in the traditional trapping process are effectively avoided, and the technical problem that the normal production is influenced due to the blockage of a discharge port at the bottom of the trapping device is effectively solved.

According to the invention, liquid nitrogen is directly introduced into the trapping device and directly contacts with the reaction gas, so that the contact heat exchange area of the reaction gas and a heat exchange medium is remarkably increased compared with that of the traditional jacket type trapping process, meanwhile, the multistage trapping process is matched, the unqualified solid waste amount is reduced to a certain extent, and the trapping efficiency and the production benefit are greatly improved.

As a preferred embodiment of the present invention, the trapping method specifically includes:

reaction gas conveyed by an upstream production line is filtered by a bag type filtering device and then is introduced into a fixed bed filtering device through a heat preservation pipe;

(II) the reaction gas discharged by the fixed bed filtering device sequentially flows through a first trapping device and a second trapping device, is respectively mixed with liquid nitrogen in the first trapping device and the second trapping device, and is desublimated after being mixed with the liquid nitrogen, and tetrachloroisophthalonitrile separated out of the reaction gas is trapped;

(III) introducing the tail gas discharged by the second trapping device into a tail gas filtering device, wherein the filtered tail gas is divided into two parts, one part is recycled to the first trapping device, and the other part is discharged after tail gas treatment.

As a preferable technical scheme, in the step (I), a jacket is arranged on the outer side of the heat preservation pipe, and a heat-conducting medium is introduced into the jacket.

Preferably, the heat conducting medium is heat conducting oil.

Preferably, the heat transfer oil is low-temperature heat transfer oil, medium-temperature heat transfer oil or high-temperature heat transfer oil, and further preferably, the heat transfer oil is high-temperature heat transfer oil.

Preferably, the temperature of the heat-conducting medium is 330 to 350 ℃, for example, 330 ℃, 331 ℃, 332 ℃, 333 ℃, 334 ℃, 335 ℃, 336 ℃, 337 ℃, 338 ℃, 339 ℃, 340 ℃, 341 ℃, 342 ℃, 343 ℃, 344 ℃, 345 ℃, 346 ℃, 347 ℃, 348 ℃, 349 ℃ or 350 ℃, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the temperature in the heat preservation pipe is controlled by adjusting the temperature of the heat conducting medium in the jacket.

Preferably, automatic interlocking control is carried out between the temperature in the heat preservation pipe and the flow of the heat-conducting medium.

Preferably, the flow rate of the heat-conducting medium is 20-30 m³H, for example, may be 20m³/h、21m³/h、22m³/h、23m³/h、24m³/h、25m³/h、26m³/h、27m³/h、28m³/h、29m³H or 30m³H, further preferably, the flow rate of the heat-conducting medium is 25m³And/h, but not limited to, the recited values, and other values not recited within the range of values are equally applicable.

Preferably, the temperature in the heat-insulating tube is controlled to 320 to 340 ℃, for example, 320 ℃, 321 ℃, 322 ℃, 323 ℃, 324 ℃, 325 ℃, 326 ℃, 327 ℃, 328 ℃, 329 ℃, 330 ℃, 331 ℃, 332 ℃, 333 ℃, 334 ℃, 335 ℃, 336 ℃, 337 ℃, 338 ℃, 339 ℃ or 340 ℃, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.

In the step (II), the liquid nitrogen is respectively and independently introduced into the first trapping device and the second trapping device through the uniform distribution device.

Preferably, the trapping temperatures in the first trapping device and the second trapping device are respectively controlled by independently adjusting the flow rates of liquid nitrogen.

Preferably, automatic interlocking control is carried out between the trapping temperature and the liquid nitrogen flow rate in the first trapping device and the second trapping device.

Preferably, the liquid nitrogen is introduced into the first capturing device at a flow rate of 75 to 200kg/h, for example, 75kg/h, 80kg/h, 85kg/h, 90kg/h, 95kg/h, 100kg/h, 105kg/h, 110kg/h, 115kg/h, 120kg/h, 125kg/h, 130kg/h, 135kg/h, 140kg/h, 145kg/h, 150kg/h, 155kg/h, 160kg/h, 165kg/h, 170kg/h, 175kg/h, 180kg/h, 185kg/h, 190kg/h, 195kg/h or 200kg/h, but not limited to the values listed, and other values not listed in this range are equally applicable.

Preferably, the collection temperature in the first collection device is controlled to 140 to 180 ℃, for example, 140 ℃, 142 ℃, 144 ℃, 146 ℃, 148 ℃, 150 ℃, 152 ℃, 154 ℃, 156 ℃, 158 ℃, 160 ℃, 162 ℃, 164 ℃, 168 ℃, 170 ℃, 172 ℃, 174 ℃, 176 ℃, 178 ℃ or 180 ℃, and more preferably, the collection temperature in the first collection device is controlled to 150 to 170 ℃, but is not limited to the values listed, and other values not listed within the range of values are also applicable.

Preferably, the flow rate of the liquid nitrogen introduced into the second trap device is 20 to 45kg/h, and may be, for example, 20kg/h, 21kg/h, 22kg/h, 23kg/h, 24kg/h, 25kg/h, 26kg/h, 27kg/h, 28kg/h, 29kg/h, 30kg/h, 31kg/h, 32kg/h, 33kg/h, 34kg/h, 35kg/h, 36kg/h, 37kg/h, 38kg/h, 39kg/h, 40kg/h, 41kg/h, 42kg/h, 43kg/h, 44kg/h or 45kg/h, but is not limited to the values listed, and other values not listed in the range of values are also applicable.

Preferably, the collection temperature in the second collection device is controlled to be 100 to 140 ℃, for example, 100 ℃, 102 ℃, 104 ℃, 106 ℃, 108 ℃, 110 ℃, 112 ℃, 114 ℃, 116 ℃, 118 ℃, 120 ℃, 122 ℃, 124 ℃, 126 ℃, 128 ℃, 130 ℃, 132 ℃, 134 ℃, 136 ℃, 138 ℃ or 140 ℃, and more preferably, the collection temperature in the second collection device is 110 to 130 ℃, but is not limited to the values listed, and other values not listed in the numerical range are also applicable.

Preferably, the first trapping device has a trapping efficiency of 70 to 90%, for example, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, or 90%, but is not limited to the recited values, and other values not recited in the above range are also applicable.

Preferably, the second capturing device has a capturing efficiency of 5 to 25%, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24% or 25%, but is not limited to the recited values, and other values not recited in the above range are also applicable.

Preferably, the liquid nitrogen content is 99 to 99.9%, for example, 99.0%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, or 99.9%, and more preferably, the liquid nitrogen content is 99.9%, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, the tetrachloroisophthalonitrile captured by the first capture device and the tetrachloroisophthalonitrile captured by the second capture device are respectively led into a product conveying system.

In a preferred technical scheme of the present invention, in the step (iii), a jacket is arranged outside the tail gas filtering device, and a cooling medium is introduced into the jacket.

Preferably, the cooling medium is circulating water or frozen brine, and further preferably, the cooling medium is circulating water.

Preferably, the temperature of the cooling medium is 10 to 20 ℃, for example, 10 ℃, 11 ℃, 12 ℃, 13 ℃, 14 ℃, 15 ℃, 16 ℃, 17 ℃, 18 ℃, 19 ℃ or 20 ℃, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, the temperature within the exhaust gas filtering device is controlled by adjusting the flow rate of the cooling medium within the jacket.

Preferably, the automatic interlocking control is carried out between the temperature in the tail gas filtering device and the flow of the cooling medium.

Preferably, the flow of the cooling medium is 10-15 m³H, for example, may be 10m³/h、11m³/h、12m³/h、13m³/h、14m³H or 15m³And/h, but not limited to, the recited values, and other values not recited within the range of values are equally applicable.

Preferably, the temperature in the exhaust gas filtering device is controlled to be 50 to 80 ℃, for example, 50 ℃, 52 ℃, 54 ℃, 56 ℃, 58 ℃, 60 ℃, 62 ℃, 64 ℃, 66 ℃, 68 ℃, 70 ℃, 72 ℃, 74 ℃, 76 ℃, 78 ℃ or 80 ℃, and more preferably, the temperature of the exhaust gas filtering device is controlled to be 60 to 70 ℃, but the temperature is not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, the tail gas discharged from the second capturing device is filtered by a tail gas filtering device to remove solid waste therein, and the tail gas after being filtered to remove solid waste is divided into a first tail gas and a second tail gas according to a volume ratio, wherein the volume ratio of the first tail gas to the second tail gas is 0.11-0.25, for example, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24 or 0.25, but not limited to the enumerated values, and other non-enumerated values in the numerical range are also applicable.

Preferably, the first tail gas is returned to the first trapping device through a fan, and the cold energy in the first tail gas is circularly applied in the first trapping device.

In the invention, the tail gas filtered by the tail gas filtering device returns to the first capturing device through the fan, thereby effectively utilizing the cold energy of the tail gas and greatly reducing the loss of liquid nitrogen.

Preferably, the air volume of the fan is 150-300 m³H, for example, may be 150m³/h、160m³/h、170m³/h、180m³/h、190m³/h、200m³/h、210m³/h、220m³/h、230m³/h、240m³/h、250m³/h、260m³/h、270m³/h、280m³/h、290m³H or 300m³H, further preferably, the air volume of the fan is 300m³And/h, but not limited to, the recited values, and other values not recited within the range of values are equally applicable.

Preferably, the second tail gas is treated by the tail gas treatment device and then is led out by the exhaust fan for emission.

Preferably, the flow of the exhaust fan is 5000-10000 m³H may be, for example, 5000m³/h、5500m³/h、6000m³/h、6500m³/h、7000m³/h、7500m³/h、8000m³/h、8500m³/h、9000m³/h、9500m³H or 10000m³H, further preferably, the flow of the exhaust fan is 10000m³And/h, but not limited to, the recited values, and other values not recited within the range of values are equally applicable.

Preferably, the wind pressure of the exhaust fan is 1000 to 2500Pa, for example, 1000Pa, 1100Pa, 1200Pa, 1300Pa, 1400Pa, 1500Pa, 1600Pa, 1700Pa, 1800Pa, 1900Pa, 2000Pa, 2100Pa, 2200Pa, 2300Pa, 2400Pa or 2500Pa, and further preferably, the wind pressure of the exhaust fan is 2000Pa, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.

In a second aspect, the present invention provides a capturing system for tetrachloroisophthalonitrile reaction gas, the capturing system being used for carrying out the capturing method of the first aspect, the capturing system comprising a filtration unit and a multistage capturing unit which are connected.

The multistage trapping unit comprises at least two trapping devices which are connected in sequence, and the trapping devices are respectively connected with a liquid nitrogen supply device.

As a preferable technical solution of the present invention, the filtration unit includes a bag filtration device and a fixed bed filtration device connected in sequence.

Preferably, the bag type filtering device and the fixed bed filtering device are connected through a heat preservation pipe.

Preferably, the outer side of the heat preservation pipe is provided with a jacket, and a heat-conducting medium is introduced into the jacket.

Preferably, the heat conducting medium is heat conducting oil.

Preferably, a reaction gas temperature sensor is arranged in the heat preservation pipe, a heat-conducting medium flow control valve is arranged on a jacket liquid inlet pipeline of the heat preservation pipe, the reaction gas temperature sensor is connected with the reaction gas flow control valve in a feedback mode, and the opening degree of the heat-conducting medium flow control valve is controlled in real time through the reaction gas temperature in the pipe detected by the reaction gas temperature sensor.

As a preferable technical solution of the present invention, the air inlet of the trapping device is provided with a uniform distribution device.

Preferably, the product outlets of the trapping devices are respectively connected with a product conveying system.

Preferably, the multistage trapping unit comprises a first trapping device and a second trapping device which are connected in sequence, and the first trapping device and the second trapping device are respectively connected with a liquid nitrogen supply device.

Preferably, a first electric control valve is arranged on a connecting pipeline between the first trapping device and the liquid nitrogen supply device, and a second electric control valve is arranged on a connecting pipeline between the first trapping device and the liquid nitrogen supply device.

Preferably, a first temperature sensing device and a second temperature sensing device are respectively arranged in the first trapping device and the second trapping device, the first temperature sensing device is connected with the first electric control valve in a feedback mode, and the second temperature sensing device is connected with the second electric control valve in a feedback mode.

As a preferable technical scheme, the trapping system further comprises a tail gas filtering device and a tail gas treatment device which are sequentially connected with the outlets of the multistage trapping units.

Preferably, the outer side of the tail gas filtering device is provided with a jacket, and a cooling medium is introduced into the jacket.

Preferably, the cooling medium is circulating water or frozen brine, and further preferably, the cooling medium is circulating water.

Preferably, a tail gas temperature sensor is arranged in the tail gas filtering device, a cooling medium flow control valve is arranged on a jacket liquid inlet pipeline of the tail gas filtering device, the tail gas temperature sensor is connected with the cooling medium flow control valve in a feedback mode, and the opening degree of the cooling medium flow control valve is controlled in real time through the tail gas temperature detected by the tail gas temperature sensor.

Preferably, the tail gas outlet of the tail gas filtering device is divided into two paths, one path is connected with the first trapping device in a returning mode, and the other path is connected with a downstream tail gas treatment device.

In a preferred embodiment of the present invention, a fan is disposed on the connection pipeline between the tail gas filtering device and the first trapping device.

Preferably, the material of the fan is steel lining PTFE or glass fiber reinforced plastic, and further preferably, the material of the fan is glass fiber reinforced plastic.

Preferably, the exhaust port of the tail gas treatment device is provided with an induced draft fan.

The system refers to an equipment system, or a production equipment.

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the invention, liquid nitrogen is used as a cooling medium of the trapping device, the liquid nitrogen enters the trapping device through the distributor to be directly vaporized, tetrachloroisophthalonitrile gas in reaction gas is contacted with the liquid nitrogen to be directly desublimated and separated out to the bottom of the trapping device, and the tetrachloroisophthalonitrile gas enters the product bin through the conveyor, so that the traditional air cooling or water cooling mode is replaced by liquid nitrogen cooling, the phenomena of material wall formation and material collapse caused by cooling of the reaction gas by using a jacket cooling medium in the traditional trapping process are effectively avoided, and the technical problem that the normal production is influenced due to the blockage of a discharge port at the bottom of the trapping device is effectively solved.

(2) According to the invention, liquid nitrogen is directly introduced into the trapping device and directly contacts with the reaction gas, so that the contact heat exchange area of the reaction gas and a heat exchange medium is remarkably increased compared with that of the traditional jacket type trapping process, meanwhile, the multistage trapping process is matched, the unqualified solid waste amount is reduced to a certain extent, and the trapping efficiency and the production benefit are greatly improved.

(3) The tail gas part filtered by the tail gas filtering device returns to the catching device through the fan, thereby effectively utilizing the cold energy of the tail gas and greatly reducing the loss of liquid nitrogen.

Drawings

Fig. 1 is a block diagram of a system according to an embodiment of the present invention.

Detailed Description

It is to be understood that in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be taken as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

It should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "disposed," "connected" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

In one embodiment, the invention provides a capture system for tetrachloroisophthalonitrile reaction gas, which is shown in figure 1 and comprises a filtering unit and a multi-stage capture unit which are connected.

The filtering unit comprises a bag type filtering device and a fixed bed filtering device which are connected in sequence. The bag type filtering device is connected with the fixed bed filtering device through a heat preservation pipe, a jacket is arranged on the outer side of the heat preservation pipe, a heat conducting medium is introduced into the jacket, and the heat conducting medium is heat conducting oil. The reaction temperature sensor is arranged in the heat preservation pipe, the heat-conducting medium flow control valve is arranged on the jacket liquid inlet pipeline of the heat preservation pipe, the reaction temperature sensor is connected with the reaction gas flow control valve in a feedback mode, and the opening degree of the heat-conducting medium flow control valve is controlled in real time through the reaction gas temperature in the pipe detected by the reaction gas temperature sensor.

The multistage trapping unit comprises at least two trapping devices which are connected in sequence, and the trapping devices are respectively connected with a liquid nitrogen supply device. The air inlet of the trapping device is provided with a uniform distribution device, and the product outlets of the trapping device are respectively connected with a product conveying system. In the present embodiment, the multistage trapping unit includes a first trapping device and a second trapping device connected in sequence, and the first trapping device and the second trapping device are connected to a liquid nitrogen supply device, respectively. A first electric control valve is arranged on a connecting pipeline of the first trapping device and the liquid nitrogen supply device, and a second electric control valve is arranged on a connecting pipeline of the first trapping device and the liquid nitrogen supply device. And a first temperature sensing device and a second temperature sensing device are respectively arranged in the first trapping device and the second trapping device, the first temperature sensing device is connected with the first electric control valve in a feedback manner, and the second temperature sensing device is connected with the second electric control valve in a feedback manner.

The trapping system also comprises a tail gas filtering device and a tail gas processing device which are sequentially connected with the outlets of the multistage trapping units. The outer side of the tail gas filtering device is provided with a jacket, and a cooling medium is introduced into the jacket and can be selected from circulating water or frozen brine. Be provided with tail gas temperature sensor in the tail gas filter equipment, be provided with cooling medium flow control valve on tail gas filter equipment's the cover feed liquor pipeline, tail gas temperature sensor and cooling medium flow control valve feedback are connected, the tail gas temperature real-time control cooling medium flow control valve's that detects through tail gas temperature sensor aperture. The tail gas outlet of the tail gas filtering device is divided into two paths, one path is connected with the first trapping device in a loop mode, and the other path is connected with the downstream tail gas treatment device. And a fan is arranged on a connecting pipeline between the tail gas filtering device and the first trapping device, and the material of the fan can be steel lining PTFE or glass fiber reinforced plastic. And an induced draft fan is arranged at an exhaust port of the tail gas treatment device.

In another embodiment, the present invention provides a method for capturing tetrachloroisophthalonitrile reaction gas, the method comprising:

(1) reaction gas conveyed by the upstream production line is filtered by the bag type filtering device and then is introduced into the fixed bed filtering device through the heat preservation pipe. Introducing a heat-conducting medium into a jacket of the heat-insulating pipe, and heating reaction gas flowing through the heat-insulating pipe, wherein the temperature of the heat-conducting medium is 330-350 ℃; the temperature in the heat-insulating pipe is controlled by adjusting the flow of the heat-conducting medium in the jacket, and the flow of the heat-conducting medium is 20-30 m³The temperature in the heat preservation pipe is controlled to be 320-340 ℃;

(2) the method comprises the following steps that reaction gas discharged by a fixed bed filtering device sequentially flows through a first trapping device and a second trapping device, liquid nitrogen with the content of 99-99.9% is respectively and independently introduced into the first trapping device and the second trapping device through a uniform distribution device, the reaction gas is respectively mixed with the liquid nitrogen in the first trapping device and the second trapping device, the reaction gas is mixed with the liquid nitrogen and then desublimated, tetrachloroisophthalonitrile separated out of the reaction gas is trapped and introduced into a product conveying system;

the method comprises the following steps of respectively controlling the trapping temperature in a first trapping device and the trapping temperature in a second trapping device by independently adjusting the flow of liquid nitrogen, wherein the flow of the liquid nitrogen introduced into the first trapping device is 75-200 kg/h, and the trapping temperature in the first trapping device is controlled at 140-180 ℃; the flow of liquid nitrogen introduced into the second trapping device is 20-45 kg/h, and the trapping temperature in the second trapping device is controlled to be 100-140 ℃; the collecting efficiency of the first collecting device is 70-90%, and the collecting efficiency of the second collecting device is 5-25%;

(3) the tail gas discharged by the second trapping device is introduced into a tail gas filtering device, the tail gas entering the tail gas filtering device is cooled by a cooling medium in a jacket of the tail gas filtering device, the cooling medium is circulating water or frozen salt water, the temperature of the cooling medium is 10-20 ℃, the temperature of the cooling medium in the tail gas filtering device is controlled by adjusting the flow of the cooling medium in the jacket, and the flow of the cooling medium is 10-15 m³The temperature in the tail gas filtering device is controlled to be 50-80 ℃;

the tail gas filtering device filters solid waste in the tail gas filtering device, the tail gas after solid waste filtering is divided into a first tail gas and a second tail gas according to the volume ratio, the volume ratio of the first tail gas to the second tail gas is 0.11-0.25, the first tail gas is returned to the first trapping device through the fan, cold in the first tail gas is circularly applied to the first trapping device, and the air volume of the fan is 150-300 m³H; the second tail gas is treated by a tail gas treatment device and then is led out and discharged by an exhaust fan, and the flow of the exhaust fan is 5000-10000 m³And h, the air pressure of the exhaust fan is 1000-2500 Pa.