阅读说明：本技术 含苯胺气体的处理方法及其系统 (Method and system for treating aniline-containing gas ) 是由 裴义霞 顾军民 于 2020-07-02 设计创作，主要内容包括：本发明涉及苯胺制备领域,公开了一种含苯胺气体的处理方法,该方法包括以下步骤：(1)在急冷塔中,将含有苯胺的反应平衡混合气与补充喷淋液逆向接触,得到急冷塔塔底料液和急冷塔塔顶气相；(2)急冷塔塔底料液分为采出物料和循环物料两部分,循环物料返回急冷塔作喷淋液循环使用；(3)将急冷塔塔顶气相进行冷凝,得到不凝气和冷凝液；(4)将所述冷凝液进行油水分离,得到粗苯胺和含苯胺废水。本发明采用带有补充喷淋液的急冷塔,避免了设备堵塞的同时,优化了能量利用,实现了装置长周期稳定运行和节能降耗的目的。(The invention relates to the field of aniline preparation, and discloses a method for treating aniline-containing gas, which comprises the following steps: (1) in a quench tower, reversely contacting reaction equilibrium mixed gas containing aniline with supplementary spray liquid to obtain feed liquid at the bottom of the quench tower and gas phase at the top of the quench tower; (2) the material liquid at the bottom of the quenching tower is divided into two parts of extracted material and circulating material, and the circulating material returns to the quenching tower to be used as spraying liquid for recycling; (3) condensing the gas phase at the top of the quenching tower to obtain non-condensable gas and condensate; (4) and carrying out oil-water separation on the condensate to obtain crude aniline and aniline-containing wastewater. The invention adopts the quench tower with the supplementary spray liquid, avoids equipment blockage, optimizes energy utilization and realizes the purposes of long-period stable operation of the device, energy conservation and consumption reduction.)

1. A method of treating a aniline-containing gas, the method comprising the steps of:

(1) in a quench tower, reversely contacting reaction equilibrium mixed gas containing aniline with supplementary spray liquid to obtain feed liquid at the bottom of the quench tower and gas phase at the top of the quench tower;

(2) the material liquid at the bottom of the quenching tower is divided into two parts of extracted material and circulating material, and the circulating material is returned to the quenching tower to be used as spraying liquid for recycling;

(3) condensing the gas phase at the top of the quenching tower to obtain non-condensable gas and condensate;

(4) and carrying out oil-water separation on the condensate to obtain crude aniline and aniline-containing wastewater.

2. A method of treating a aniline-containing gas, the method comprising the steps of:

(1) reaction equilibrium mixed gas containing aniline enters a quench tower from the bottom, and supplementary spray liquid is sprayed from the top of the quench tower to obtain feed liquid at the bottom of the quench tower and gas phase at the top of the quench tower;

(2) after the feed liquid at the bottom of the quenching tower is led out by a circulating pump, part of the feed liquid is used as a produced material, and the rest of the feed liquid is used as a circulating material and returned to the quenching tower to be used as a spraying liquid for recycling;

(3) the gas phase at the top of the quenching tower enters a condenser for condensation to obtain non-condensable gas and condensate;

(4) and sending the condensate into an oil-water separator for oil-water separation to obtain crude aniline and aniline-containing wastewater.

3. The process of claim 1 or 2, wherein the reaction equilibrium gas mixture is from a fluidized bed gas phase hydrogenation of nitrobenzene;

the reaction equilibrium mixed gas contains aniline, hydrogen and water, and the content of aniline is 40-80 wt%, preferably 55-75 wt% based on the total amount of the reaction equilibrium mixed gas;

preferably, the reaction equilibrium gas mixture temperature is 180-260 ℃, preferably 210-240 ℃.

4. The treatment process according to claim 1 or 2, wherein in step (1), the supplementary spray liquid is an aqueous solution containing aniline, and the water content is 92-99.9 wt%, preferably 94-97 wt%;

preferably, the temperature of the supplementary spraying liquid is 10-60 ℃, preferably 20-50 ℃;

preferably, the supplementary spray liquid is used in an amount of 10 to 60 parts by weight, preferably 15 to 40 parts by weight, relative to 100 parts by weight of the reaction equilibrium gas mixture;

preferably, at least part of the supplementary spray liquid in the step (1) is provided by the aniline-containing wastewater in the step (4).

5. The process of claim 1 or 2, wherein the quench tower has a bottom temperature of 70-115 ℃ and a top temperature of 65-110 ℃;

preferably, the bottom temperature of the quenching tower is 75-110 ℃, and the top temperature of the quenching tower is 69-100 ℃;

preferably, the quench tower comprises at least two layers of sprayers and at least one layer of mist eliminator, more preferably, the quench tower comprises 2-6 layers of sprayers and 2-4 layers of mist eliminator.

6. A process according to claim 1 or 2, wherein in step (2) the mined material constitutes 3-25 wt%, preferably 5-20 wt%, of the recycled material;

preferably, the aniline content of the bottom stream of the quench tower is from 90 to 99.9% by weight, preferably from 96 to 99.9% by weight.

7. The process according to claim 1 or 2, wherein the liquefaction recovery rate of aniline in the reaction equilibrium gas mixture in step (1) in the quenching tower is not less than 50%, preferably not less than 60%, and more preferably 60% to 90%.

8. The process according to claim 1 or 2, wherein the gas phase at the top of the quenching tower contains aniline, hydrogen and water;

preferably, the aniline content in the gas phase at the top of the quench tower is not more than 40 wt.%, more preferably not more than 20 wt.%.

9. The processing method according to claim 1 or 2, wherein the method further comprises: sending the reaction equilibrium mixed gas into a hydrogen heat exchanger containing a solid particle injection system for heat exchange, and sending low-temperature reaction gas with solid particles obtained at the outlet of the hydrogen heat exchanger into a quench tower;

the hydrogen heat exchanger with the solid particle injection system comprises a solid buffer tank and a hydrogen heat exchanger, and the bottom of the solid buffer tank is communicated with the top of the hydrogen heat exchanger;

preferably, the method further comprises: when the pressure difference of the hydrogen heat exchanger exceeds a set value, adding solid particles into a solid buffer tank, and spraying the solid particles to the top of the hydrogen heat exchanger under the drive of carrier gas;

preferably, the hydrogen heat exchanger is provided with a differential pressure sensor, and the carrier gas and solid buffer tank pipelines are provided with interlocking pneumatic valves; when the pressure difference of the hydrogen heat exchanger exceeds a set value, a signal is transmitted to an interlocking pneumatic valve through a pressure difference sensor, the valve is opened, solid particles are added into a solid buffer tank and are injected to the top of the hydrogen heat exchanger under the driving of carrier gas, and when the pressure difference of the hydrogen heat exchanger is lower than the set value, the valve of the interlocking pneumatic valve is closed in a linkage manner;

preferably, the solid particles are inert solid particles with a particle size of 0.1-5 mm;

preferably, the carrier gas is selected from at least one of nitrogen, helium, neon, and hydrogen;

preferably, the temperature of the low-temperature reaction gas is 110-.

10. The treatment method according to claim 9, wherein in the step (1), the supplementary spray liquid is an aqueous solution containing aniline, and the water content is 92-99.9 wt%, preferably 94-97 wt%;

preferably, the temperature of the supplementary spraying liquid is 30-50 ℃;

preferably, the supplementary spray liquid is used in an amount of 10 to 30 parts by weight with respect to 100 parts by weight of the low-temperature reaction gas.

11. The treatment method according to claim 10, wherein the supplementary spray liquid is divided into a supplementary spray liquid I and a supplementary spray liquid II in a weight ratio of 0.1 to 10, and the supplementary spray liquid I and the supplementary spray liquid II are respectively sprayed at the top and the middle of the quenching tower;

preferably, the supplementary spray liquid is used in a total amount of 5 to 25 parts by weight with respect to 100 parts by weight of the low-temperature reaction gas.

12. A system for treating a aniline-containing gas, the system comprising:

a quench tower, a condenser and an oil-water separator; an outlet at the top of the quenching tower is communicated with an inlet of a condenser, and a liquid phase outlet of the condenser is communicated with an inlet of the oil-water separator;

the bottom and the top of the quenching tower are provided with circulating lines so that at least part of the bottom material of the quenching tower is circulated to the top of the quenching tower;

the top of the quenching tower is also communicated with a supplementary spraying pipeline so as to introduce supplementary spraying liquid into the quenching tower.

13. The treatment system of claim 12, wherein the quench tower comprises at least two layers of sprayers and at least one layer of mist eliminator, more preferably the quench tower comprises 2-6 layers of sprayers and 2-4 layers of mist eliminator.

14. The treatment system of claim 12 or 13, wherein the circulating pipeline is further provided with a circulating pump, and the circulating pump is used for leading out the bottom material of the quenching tower to obtain a extracted material and a circulating material;

preferably, the system further comprises a solid-liquid separator which is communicated with the circulating pump so as to carry out solid-liquid separation on the produced material.

15. The treatment system of any one of claims 12 to 14, wherein the system further comprises a solids surge tank and a hydrogen heat exchanger, an outlet of the solids surge tank being in communication with a top inlet of the hydrogen heat exchanger; the bottom outlet of the hydrogen heat exchanger is communicated with the inlet of the quenching tower; the solid buffer tank is provided with a carrier gas input pipeline and a solid particle input pipeline;

preferably, the hydrogen heat exchanger is provided with a differential pressure sensor, the carrier gas input pipeline is provided with an interlocking pneumatic valve, and the differential pressure sensor controls the opening and closing of the interlocking pneumatic valve through the change of differential pressure.

Technical Field

The invention relates to the field of aniline preparation, and particularly relates to a treatment method and a treatment system for aniline-containing gas.

Background

Aniline is an organic chemical product with wide application, and can be used as rubber vulcanization accelerator, dye, medicine, explosive raw material, diphenylmethane polyurethane (MDI) raw material and the like.

Most of the existing aniline production devices adopt a nitrobenzene catalytic hydrogenation method, and the aniline production method by the nitrobenzene catalytic hydrogenation method is divided into a gas-phase hydrogenation method and a liquid-phase hydrogenation method. The gas phase hydrogenation method is divided into two processes of fixed bed gas phase catalytic hydrogenation and fluidized bed gas phase hydrogenation due to different reactor forms. At present, domestic enterprises mostly adopt a fluidized bed gas-phase hydrogenation process, the process is a gas-liquid two-phase reaction, reaction heat is brought out by vaporization of reaction products, the selectivity of aniline is more than 99%, the temperature of the reaction products at the outlet of a fluidized bed is 210-240 ℃, and the components of the reaction products are mainly aniline, water and hydrogen. After the new hydrogen heat exchange, the gas-liquid separation is realized through two-step condensation. The method effectively avoids the condition of local overheating, reduces the occurrence of side reactions and prolongs the service life of the catalyst.

Because the strength of the copper-based catalyst for preparing aniline by nitrobenzene hydrogenation is not high, fine catalyst powder particles with the particle size of less than 10 microns can be formed after long-term abrasion in a fluidized bed. This fraction is difficult to completely trap by cyclones in the fluidised bed and therefore the reactants at the outlet of the fluidised bed contain many catalyst fines and are easily carried by the gas stream to the heat exchanger at the outlet of the fluidised bed. When crude aniline is gradually cooled in a multistage heat exchanger, catalyst particles can be combined with tar in reaction products, adhere to the tar and accumulate in the tube array of the reaction gas heat exchanger, scale layers on the inner wall of the tube array are gradually thickened along with the extension of operation time, and channels in the tube array are gradually reduced, so that the pipeline resistance is increased, and the energy consumption is increased. When the scale layer reaches a certain thickness, the operating pressure of the reaction system increases significantly, thereby deteriorating the operating conditions of the fluidized bed reaction system. In severe cases, the heat exchanger pipeline is basically completely blocked after the device operates for 4-5 months, and the device must be stopped and cleaned, thereby consuming time, polluting environment and influencing normal production.

CN104098473A is through increasing the scrubber at the reactor exit, and the mixed gaseous material of reaction gets into from the scrubber lower part in the middle of, carries out the forced spraying with crude aniline of 40-80 ℃, and the liquid phase material temperature of scrubber bottom exit is 130-. CN105418437A discloses an energy-saving method for an aniline device, which adopts 10-80 ℃ crude aniline and high-temperature reaction mixed gas phase materials to exchange heat in a tower heat exchanger, and improves the operation period of the device to 8 months.

In conclusion, in the prior art, the problem of heat exchanger blockage is still not thoroughly solved in the condensation process of the mixed gas phase material generated by the reaction, and the long-period stable operation of the process for preparing aniline by hydrogenation of the nitrobenzene fluidized bed is further influenced.

Disclosure of Invention

The invention aims to solve the problems that a heat exchanger is easy to block and a device cannot run for a long time in the condensation process of aniline reaction equilibrium mixed gas in the prior art, and provides a method and a system for treating aniline-containing gas.

In order to achieve the above object, a first aspect of the present invention provides a method for treating a aniline-containing gas, the method comprising the steps of:

(1) in a quench tower, reversely contacting reaction equilibrium mixed gas containing aniline with supplementary spray liquid to obtain feed liquid at the bottom of the quench tower and gas phase at the top of the quench tower;

(2) the material liquid at the bottom of the quenching tower is divided into two parts of extracted material and circulating material, and the circulating material returns to the quenching tower to be used as spraying liquid for recycling;

(3) condensing the gas phase at the top of the quenching tower to obtain non-condensable gas and condensate;

(4) and carrying out oil-water separation on the condensate to obtain crude aniline and aniline-containing wastewater.

In a second aspect, the present invention provides a method for treating a aniline-containing gas, comprising the steps of:

(1) reaction equilibrium mixed gas containing aniline enters a quench tower from the bottom, and supplementary spray liquid is sprayed from the top of the quench tower to obtain feed liquid at the bottom of the quench tower and gas phase at the top of the quench tower;

(2) after the feed liquid at the bottom of the quenching tower is led out by a circulating pump, part of the feed liquid is used as the extracted material, and the rest of the feed liquid is used as the circulating material and returns to the quenching tower to be used as the spraying liquid for recycling;

(3) the gas phase at the top of the quenching tower enters a condenser for condensation to obtain non-condensable gas and condensate;

(4) and sending the condensate into an oil-water separator for oil-water separation to obtain crude aniline and aniline-containing wastewater.

Preferably, the supplementary spray liquid is used in an amount of 10 to 60 parts by weight, preferably 15 to 40 parts by weight, relative to 100 parts by weight of the reaction equilibrium gas mixture.

Preferably, at least part of the supplementary spray liquid in the step (1) is provided by the aniline-containing wastewater in the step (4).

Preferably, the method further comprises: sending the reaction equilibrium mixed gas into a hydrogen heat exchanger containing a solid particle injection system for heat exchange, and sending low-temperature reaction gas with solid particles obtained at the outlet of the hydrogen heat exchanger into a quench tower; the hydrogen heat exchanger with the solid particle injection system comprises a solid buffer tank and a hydrogen heat exchanger, and the bottom of the solid buffer tank is communicated with the top of the hydrogen heat exchanger.

Preferably, the method further comprises: when the pressure difference of the hydrogen heat exchanger exceeds a set value, solid particles are added into a solid buffer tank and are sprayed to the top of the hydrogen heat exchanger under the drive of carrier gas.

Preferably, the hydrogen heat exchanger is provided with a differential pressure sensor, and the carrier gas and solid buffer tank pipelines are provided with interlocking pneumatic valves; when the pressure difference of the hydrogen heat exchanger exceeds a set value, a signal is transmitted to the interlocking pneumatic valve through the pressure difference sensor, the valve is opened, solid particles are added into the solid buffer tank and are injected to the top of the hydrogen heat exchanger under the driving of carrier gas, and when the pressure difference of the hydrogen heat exchanger is lower than the set value, the valve of the interlocking pneumatic valve is closed in a linkage mode. Further preferably, the supplementary spray liquid is used in an amount of 10 to 30 parts by weight with respect to 100 parts by weight of the low-temperature reaction gas.

In a third aspect, the present invention provides a system for treating a gas containing aniline, the system comprising:

a quench tower, a condenser and an oil-water separator; an outlet at the top of the quenching tower is communicated with an inlet of a condenser, and a liquid phase outlet of the condenser is communicated with an inlet of the oil-water separator;

the bottom and the top of the quenching tower are provided with circulating lines so that at least part of the bottom material of the quenching tower is circulated to the top of the quenching tower;

the top of the quenching tower is also communicated with a supplementary spraying pipeline so as to introduce supplementary spraying liquid into the quenching tower.

Through the technical scheme, the quenching tower with the supplementary spraying liquid is adopted, so that the blockage of equipment (including a hydrogen heat exchanger and/or a condenser) is avoided, the energy utilization is optimized, and the purposes of long-period stable operation of the device and energy conservation and consumption reduction are realized.

In the preferable condition, the method adopts the aniline-containing wastewater as the supplementary spraying liquid, and compared with the method adopting crude aniline, the method has the advantages that the consumption of the spraying liquid is less, and the spraying agent does not need to be supplemented from the outside of the device, thereby being more beneficial to saving the operation cost. The inventor of the present invention found that, in this preferred case, the reaction equilibrium gas mixture and the aniline-containing wastewater both undergo phase transition in the quenching tower, and absorb a large amount of heat during the vaporization of the aniline-containing wastewater, so that the reaction equilibrium gas mixture is condensed and simultaneously achieves the effects of washing the gas with a liquid phase and trapping catalyst particles.

Under the optimal condition, the hydrogen heat exchanger containing the solid particle injection system is adopted for heat exchange, so that the heat of the reaction balance mixed gas can be effectively utilized, and the heat exchanger can be prevented from being blocked, so that the long-period stable operation of the device is further ensured, and the stability of the system is improved.

Drawings

FIG. 1 is a flow diagram of a system for treating a aniline-containing gas according to a preferred embodiment of the present invention;

FIG. 2 is a flow diagram of a system for treating a aniline-containing gas in accordance with a preferred embodiment of the present invention;

FIG. 3 is a flow chart of a system for treating a aniline-containing gas according to a preferred embodiment of the present invention.

Description of the reference numerals

1. Solid-liquid separator 2, quench tower 3, condenser

4. Oil-water separator 5, solid buffer tank 6 and hydrogen heat exchanger

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In the present invention, the pressure means absolute pressure unless otherwise specified.

In the present invention, unless otherwise stated, the terms of orientation, up, middle and down used may be three segments equally divided from top to bottom of the apparatus, or may be segmented standard, i.e. not three equally divided segments, as long as they can be distinguished by those skilled in the art.

The invention provides a method for treating aniline-containing gas, which comprises the following steps:

(1) in a quench tower, reversely contacting reaction equilibrium mixed gas containing aniline with supplementary spray liquid to obtain feed liquid at the bottom of the quench tower and gas phase at the top of the quench tower;

(2) the material liquid at the bottom of the quenching tower is divided into two parts of extracted material and circulating material, and the circulating material returns to the quenching tower to be used as spraying liquid for recycling;

(3) condensing the gas phase at the top of the quenching tower to obtain non-condensable gas and condensate;

(4) and carrying out oil-water separation on the condensate to obtain crude aniline and aniline-containing wastewater.

In a second aspect, the present invention provides a method for treating a aniline-containing gas, comprising the steps of:

(1) reaction equilibrium mixed gas containing aniline enters a quench tower from the bottom, and supplementary spray liquid is sprayed from the top of the quench tower to obtain feed liquid at the bottom of the quench tower and gas phase at the top of the quench tower;

(2) after the feed liquid at the bottom of the quenching tower is led out by a circulating pump, part of the feed liquid is used as the extracted material, and the rest of the feed liquid is used as the circulating material and returns to the quenching tower to be used as the spraying liquid for recycling;

(3) the gas phase at the top of the quenching tower enters a condenser for condensation to obtain non-condensable gas and condensate;

(4) and sending the condensate into an oil-water separator for oil-water separation to obtain crude aniline and aniline-containing wastewater.

The size and material of the quenching tower are not particularly limited, and those skilled in the art can select the material according to actual needs as long as the material can meet the requirements of the treatment capacity and the corrosion allowance of the material in the quenching tower.

According to the invention, the source of the reaction equilibrium gas mixture is selected from a wide range, and the gas mixture containing aniline can be treated by the method of the invention, and preferably, the reaction equilibrium gas mixture is from nitrobenzene fluidized bed gas phase hydrogenation.

The invention adopts the quench tower with the supplementary spray liquid, has good condensation effect on the reaction equilibrium mixed gas containing the aniline, avoids the blockage of equipment (comprising a hydrogen heat exchanger and/or a condenser), optimizes the energy utilization and realizes the purposes of long-period stable operation of the device and energy conservation and consumption reduction.

In the present invention, the selection range of the conditions for the fluidized bed gas phase hydrogenation of nitrobenzene is wide, and the conditions can be conventional in the art, and the details of the present invention are not repeated herein. The equipment for the fluidized bed gas phase hydrogenation of nitrobenzene is not particularly limited in the invention, and can be selected conventionally in the field, and the invention is not described in detail herein.

According to the present invention, preferably, the reaction equilibrium gas mixture contains aniline, hydrogen and water. The invention has wide selection range of the weight of the aniline contained in the reaction equilibrium mixed gas, and preferably, the content of the aniline is 40-80 wt%, preferably 55-75 wt% based on the total amount of the reaction equilibrium mixed gas.

According to the invention, preferably, the reaction equilibrium gas mixture also contains catalyst particles, and the content of the catalyst particles is 100-10000ppm, preferably 1000-4000 ppm.

The invention allows a wide selection of the size of the catalyst particles, typically sizes that are difficult to completely capture by the cyclones in the fluidized bed. Preferably, the size of the catalyst particles is 2 to 20 μm. The catalyst of the present invention is not particularly limited as long as it has a catalytic action in a fluidized-bed gas-phase hydrogenation reaction of nitrobenzene. For example copper based catalysts.

According to the present invention, the reaction equilibrium gas mixture temperature is preferably 180-.

According to a preferred embodiment of the present invention, in step (1), the supplementary spray liquid is an aqueous solution containing aniline, and the water content is 92 to 99.9 wt%, preferably 94 to 97 wt%. Under the optimal condition, the method is favorable for reducing the operation cost and achieving the purposes of saving energy and reducing consumption.

According to the invention, the temperature of the make-up spray is preferably 10 to 60 ℃, preferably 20 to 50 ℃. Under the optimal condition, the condensation effect on the reaction equilibrium mixed gas is better, and the system stability is favorably improved.

According to a preferred embodiment of the present invention, the supplementary spray liquid is used in an amount of 10 to 60 parts by weight, preferably 15 to 40 parts by weight, relative to 100 parts by weight of the reaction equilibrium gas mixture. Compared with the prior art, the method provided by the invention uses a smaller amount of supplementary spraying liquid, and is more beneficial to saving the operation cost.

According to a preferred embodiment of the present invention, at least a portion of the make-up spray liquid of step (1) is provided by the aniline-containing wastewater of step (4). Under the preferred embodiment, no or little additional spraying agent is needed from the outside of the device, which is more beneficial to reducing the running cost of the device. More preferably, the supplementary spray liquid in the step (1) is completely provided by the aniline-containing wastewater in the step (4). Under the preferred embodiment, spray agent does not need to be supplemented from the outside of the device, and the running cost of the device is more favorably reduced.

The operation temperature of the quenching tower is selected in a wide range, and preferably, the bottom temperature of the quenching tower is 70-115 ℃, and the top temperature of the quenching tower is 65-110 ℃. Under the optimal condition, the condensation effect on the reaction equilibrium mixed gas is better, and the system stability is favorably improved.

Further preferably, the bottom temperature of the quenching tower is 75-110 ℃, and the top temperature of the quenching tower is 69-100 ℃. Under the optimal condition, the condensation effect on the reaction equilibrium mixed gas is better, and the system stability is favorably improved.

The present invention provides a wide selection of internal configurations for a quench tower, e.g., the quench tower may have at least a spray and mist eliminator, with a wide selection of quantities for both, of course, the greater the number of spray and mist eliminator, the better the result, but at a higher cost. Preferably, the quench tower comprises at least two layers of sprayers and at least one layer of mist eliminator, more preferably, the quench tower comprises 2-6 layers of sprayers and 2-4 layers of mist eliminator. In this preferred embodiment, it is more advantageous to improve the condensation effect of the reaction equilibrium gas mixture and the trapping effect of the solid catalyst particles, thereby improving the apparatus stability.

In the present invention, the sprayer is not particularly limited as long as the spraying function of the spraying liquid can be achieved, and the sprayer can be selected conventionally in the field, and can be selected by a person skilled in the art according to actual needs. For example, the spray header comprises a spray header, the arrangement selection range of the spray header is wide, in order to further optimize the spraying effect, the quenching tower comprises two layers of spray headers, and the spray headers of the two layers of spray headers are preferably arranged densely; alternatively, the quench tower comprises four layers of sprayers, the spray headers of the four layers of sprayers are preferably staggered in 4 layers.

The mist eliminator is not particularly limited in the invention, and can be selected conventionally in the field, and the person skilled in the art can select the mist eliminator according to actual needs.

According to a preferred embodiment of the invention, in step (2), the withdrawn material constitutes 3-25% by weight, preferably 5-20% by weight, of the recycled material. Under the optimal condition, the condensation effect on the reaction equilibrium mixed gas is improved, and the stability of the system is further improved.

According to the present invention, the aniline content in the bottom stream of the quench tower is preferably from 90 to 99.9% by weight, preferably from 96 to 99.9% by weight.

According to the invention, preferably, the step (2) further comprises performing solid-liquid separation on the extracted material to obtain a clear liquid. And the solid-liquid separation enables catalyst particles contained in the extracted material to be removed. Preferably, the aniline content of the clear liquid is 90-99.9 wt.%, preferably 96-99.9 wt.%. The solid-liquid separation may be performed using a filter. The accuracy of the filter is selected from a wide range as long as it can separate catalyst particles, and preferably, a filter having a separation accuracy of 5 to 20 μm may be used as the filter.

According to the invention, the water content of the clear liquid is preferably 0.1 to 10% by weight, preferably 0.5 to 2% by weight. The clear liquid can be directly extracted or sent to a refining system.

According to the present invention, preferably, the liquefaction recovery rate of aniline in the reaction equilibrium mixed gas in the step (1) in the quenching tower is not less than 50%, preferably not less than 60%, and more preferably 60% to 90%. The liquefaction recovery rate refers to the percentage of the weight of the aniline in the tower bottom produced liquid in unit time to the weight of the aniline in the reaction equilibrium mixed gas.

According to the present invention, preferably, the gas phase at the top of the quenching tower contains aniline, hydrogen and water.

In one specific embodiment, the gas phase at the top of the quenching tower also contains nitrogen, and the content of the nitrogen is 0-1 wt%.

According to a preferred embodiment of the present invention, the aniline content in the gas phase at the top of the quench tower is not more than 40% by weight, more preferably not more than 20% by weight.

In the present invention, in step (3), the setting manner of the condenser is selected from a wide range, and specifically, for example, the setting may be one-stage condensation, two-stage condensation, or multi-stage condensation. In the invention, the first-stage condensation refers to that the gas phase at the top of the quenching tower is led into one condenser, or two or more condensers connected in parallel are subjected to primary condensation. The two-stage condensation means that the gas phase at the top of the quenching tower is introduced into two condensers which are connected in series, wherein the two condensers can be one group, two groups or more groups, the two-stage condensation is similar to the two condensers, and the two-stage condensation can be selected by a person skilled in the art as required.

And (4) obtaining non-condensable gas at the top of the condenser in the step (3), wherein the non-condensable gas can be used as a hydrogen recovery system.

According to the present invention, in the step (4), the equipment for oil-water separation is not particularly limited, and may be selected conventionally in the art. In one embodiment, an oil-water separator is used. The oil-water separator is not particularly limited in the present invention, and those skilled in the art can select the oil-water separator as needed according to actual needs.

The crude aniline obtained in the step (4) of the invention can be used as a de-aniline refining unit.

According to a preferred embodiment of the present invention, as shown in fig. 2, the method for treating a aniline-containing gas further comprises: sending the reaction equilibrium mixed gas into a hydrogen heat exchanger containing a solid particle injection system for heat exchange, and sending low-temperature reaction gas with solid particles obtained at the outlet of the hydrogen heat exchanger into a quench tower;

the hydrogen heat exchanger with the solid particle injection system comprises a solid buffer tank and a hydrogen heat exchanger, and the bottom of the solid buffer tank is communicated with the top of the hydrogen heat exchanger. Under the preferred embodiment, the heat of the reaction balance mixed gas can be effectively utilized, the blockage of equipment can be avoided, and the stability of the device can be improved.

In the present invention, the operation mode of the solid particle injection system is not particularly limited, and the operation frequency may be adjusted according to the pressure difference or the temperature difference, or the operation may be intermittently performed according to the interval time, specifically, the interval time may be 1 to 150 hours, and preferably 12 to 72 hours.

According to a preferred embodiment of the present invention, as shown in fig. 3, the method further comprises: when the pressure difference of the hydrogen heat exchanger exceeds a set value, solid particles are added into a solid buffer tank and are sprayed to the top of the hydrogen heat exchanger under the drive of carrier gas. In the preferred embodiment, when the hydrogen heat exchanger is blocked (the pressure difference exceeds a set value), the solid particles are sprayed to the top of the hydrogen heat exchanger under the driving of the carrier gas, and the blockage clearing effect can be achieved. The set value of the pressure difference is not particularly limited in the present invention, and those skilled in the art can appropriately select the set value according to the actual production process. In the present invention, it is preferable that the set value of the pressure difference is 1 to 30kPa, preferably 2 to 10 kPa.

Preferably, the hydrogen heat exchanger is provided with a differential pressure sensor, and the carrier gas and solid buffer tank pipelines are provided with interlocking pneumatic valves; when the pressure difference of the hydrogen heat exchanger exceeds a set value, a signal is transmitted to the interlocking pneumatic valve through the pressure difference sensor, the valve is opened, solid particles are added into the solid buffer tank and are injected to the top of the hydrogen heat exchanger under the driving of carrier gas, and when the pressure difference of the hydrogen heat exchanger is lower than the set value, the valve of the interlocking pneumatic valve is closed in a linkage mode. In the preferred embodiment, the device is more favorable for avoiding blockage of the device, and the stability of the system is improved.

The invention has wide selection range of the size and the type of the solid particles, and the solid particles are preferably inert solid particles with the particle size of 0.1-5 mm. Preferably, the inert solid particles are selected from at least one of alumina, silica, zirconium silicate, iron wire balls, silica gel, and zirconia.

According to the present invention, preferably, the carrier gas is selected from at least one of nitrogen, helium, neon, and hydrogen. In order to further reduce the operating costs, the carrier gas is preferably nitrogen and/or hydrogen.

According to the present invention, preferably, the temperature of the low-temperature reaction gas is 110-.

According to a preferred embodiment of the invention, the make-up spray is an aqueous solution containing aniline, the water content being 92 to 99.9 wt.%, preferably 94 to 97 wt.%.

According to the invention, the temperature of the make-up spray liquor is preferably between 30 and 50 ℃.

According to a preferred embodiment of the present invention, the supplementary spray liquid is used in an amount of 10 to 30 parts by weight with respect to 100 parts by weight of the low-temperature reaction gas. In this preferred embodiment, the supplemental spray is used in a lesser amount.

According to a preferred embodiment of the present invention, as shown in fig. 3, the supplementary spray liquid is divided into a supplementary spray liquid I and a supplementary spray liquid II in a weight ratio of 0.1 to 10, and the supplementary spray liquid I and the supplementary spray liquid II are sprayed at the top and the middle of the quenching tower, respectively. Under the preferred embodiment, the condensation effect on the reaction equilibrium mixed gas is more favorably improved, and the running cost of the device is reduced. Preferably, the supplementary spray liquid is used in a total amount of 5 to 25 parts by weight with respect to 100 parts by weight of the low-temperature reaction gas. In this preferred case, the supplementary spray is used in a smaller amount.

In a third aspect, the present invention provides a system for treating a gas containing aniline, the system comprising:

a quench tower, a condenser and an oil-water separator; an outlet at the top of the quenching tower is communicated with an inlet of a condenser, and a liquid phase outlet of the condenser is communicated with an inlet of the oil-water separator;

the bottom and the top of the quenching tower are provided with circulating lines so that at least part of the bottom material of the quenching tower is circulated to the top of the quenching tower;

the top of the quenching tower is also communicated with a supplementary spraying pipeline so as to introduce supplementary spraying liquid into the quenching tower.

The condenser is not particularly limited, and those skilled in the art can select the condenser according to actual needs, and the specific selection is as described above, and is not described herein again. In the present invention, the range of selection of the oil-water separator is wide as long as the purpose of separating the oil phase from the water phase can be achieved, and those skilled in the art can select the oil-water separator as needed according to actual needs.

According to the present invention, preferably, the quench tower comprises at least two layers of sprayers and at least one layer of mist eliminator, and more preferably, the quench tower comprises 2-6 layers of sprayers and 2-4 layers of mist eliminator. The spray and mist eliminator choices are as described above and will not be described in detail herein.

According to the invention, preferably, the circulating pipeline is further provided with a circulating pump, and the circulating pump is used for leading out materials at the bottom of the quenching tower to obtain extracted materials and circulating materials. The invention has wide selection range of the circulating pump, and can be the routine selection in the field.

According to the present invention, preferably, the system further comprises a solid-liquid separator communicating with the circulation pump to perform solid-liquid separation of the produced material. The solid-liquid separator is not particularly limited in the present invention as long as the purpose of solid-liquid separation of the produced material can be achieved, and specifically, the solid-liquid separator may be a filter having a separation accuracy of 1 to 20 μm. In the invention, the solid-liquid separation enables catalyst particles contained in the produced material to be removed.

According to a preferred embodiment of the invention, the system further comprises a solid buffer tank and a hydrogen heat exchanger, wherein an outlet of the solid buffer tank is communicated with a top inlet of the hydrogen heat exchanger; the bottom outlet of the hydrogen heat exchanger is communicated with the inlet of the quenching tower; the solid buffer tank is provided with a carrier gas input line and a solid particle input line. In the preferred embodiment, the device is more beneficial to avoiding the blockage of the equipment and improving the running stability of the device.

In the present invention, the hydrogen heat exchanger is not particularly limited and may be a conventional one in the art. The solid buffer tank has a wide selection range, and can be selected by a person skilled in the art as required according to actual needs as long as the solid particles can be stored and buffered.

According to the present invention, it is preferable that the hydrogen gas heat exchanger is provided with a differential pressure sensor, the carrier gas input line is provided with an interlock pneumatic valve, and the differential pressure sensor controls the on/off of the interlock pneumatic valve by a change in differential pressure.

In the present invention, the carrier gas is selected as described above, and the present invention is not described herein. The differential pressure sensor is not particularly limited in the present invention, and may be conventionally selected in the art. In the present invention, the interlock pneumatic valve is not particularly limited, and those skilled in the art can select the interlock pneumatic valve as needed according to actual needs.

In a preferred embodiment, the treatment with the aniline-containing gas is carried out according to the flow diagram shown in fig. 1, in particular:

feeding reaction balance mixed gas (the temperature is 210-240 ℃ and the aniline content is 55-75 wt%) from the bottom of a quench tower 2 (the bottom temperature is 75-110 ℃ and the top temperature is 69-100 ℃; two layers of spray throwers and one layer of mist eliminator are included), spraying supplementary spray liquid (the temperature is 20-60 ℃ and the water content is 92-99.9 wt%), relative to 100 parts by weight of the reaction balance mixed gas, the using amount of the supplementary spray liquid is 15-40 parts by weight) from the top of the quench tower, leading out feed liquid at the bottom of the quench tower (wherein the aniline content is 96-99.9 wt%) through a circulating pump, obtaining extracted materials and circulating materials (the extracted materials account for 3-25 wt% of the circulating materials), and returning the circulating materials to the top of the quench tower to serve as the spray liquid; the extracted material passes through a solid-liquid separator 1, catalyst particles are separated out, and the obtained clear liquid is subjected to an aniline removing refining unit. The gas phase (wherein the aniline content is not more than 20 wt%) at the top of the quenching tower enters a condenser 3, the noncondensable gas at the top of the condenser 3 enters a hydrogen recovery system, the condensed liquid removes an oil-water separator 4, a crude aniline removal refining unit is obtained at the lower layer, and part of the aniline-containing wastewater obtained at the upper layer is recycled as a supplementary spray liquid.

In a preferred embodiment, the treatment with the aniline-containing gas is carried out according to the flow diagram shown in fig. 2, in particular:

sending the reaction equilibrium mixed gas (the temperature is 210-240 ℃, and the content of aniline is 55-75 wt%) into a hydrogen heat exchanger 6 containing a solid particle injection system for heat exchange; low-temperature reaction gas (the temperature is 110-130 ℃) with solid particles obtained at the outlet of a hydrogen heat exchanger 6 enters a quench tower 2 from the bottom (the temperature of the tower bottom is 75-110 ℃, the temperature of the tower top is 69-100 ℃, two layers of spray throwers and one layer of mist eliminator are included), supplementary spray liquid (the temperature is 30-50 ℃, the content of water is 92-99.9 weight percent, relative to 100 weight parts of the reaction balance mixed gas, the use amount of the supplementary spray liquid is 10-30 weight parts) is sprayed from the tower top, feed liquid at the tower bottom of the quench tower (the content of aniline is 96-99.9 weight percent) enters a solid-liquid separator 1 through a circulating pump, after catalyst particles are separated out, the produced material aniline-removing refining unit, and the rest part of the produced material aniline-removing refining unit is used as a circulating material (the produced material accounts for 3-25 wt% of the circulating material) and returns to the top of the quenching tower 2 to be used as a spraying liquid. Introducing the gas phase (wherein the aniline content is not more than 20 wt%) at the top of the quenching tower into a condenser 3, introducing the non-condensable gas at the top of the condenser 3 into a hydrogen recovery system, removing oil-water separator 4 from condensed liquid, obtaining a crude aniline-removing refining unit at the lower layer, and recycling part of the aniline-containing wastewater obtained at the upper layer as supplementary spray liquid;

the solid particle injection system is operated intermittently (for example, operated once every 10-72 hours), when the hydrogen heat exchanger 6 is dredged, solid particles (with the particle size of 0.1-5mm) are firstly added from the top of the solid buffer tank 5 and are injected to the top of the hydrogen heat exchanger 6 under the drive of carrier gas.

In a preferred embodiment, the treatment with aniline-containing gas is carried out according to the flow diagram shown in fig. 3, in particular:

feeding the reaction equilibrium mixed gas (the temperature is 210-240 ℃, and the content of aniline is 55-75 wt%) into a hydrogen heat exchanger 6 containing a solid particle injection system; low-temperature reaction gas (the temperature is 110-130 ℃) with solid particles obtained at the outlet of a hydrogen heat exchanger 6 enters a quench tower 2 from the bottom (the temperature of the tower bottom is 75-110 ℃, the temperature of the tower top is 69-100 ℃, two layers of spray throwers and one layer of foam catcher), supplementary spray liquid comprises supplementary spray liquid I and supplementary spray liquid II (the temperature is 30-50 ℃, the content of water is 92-99 weight percent, the total consumption of the supplementary spray liquid is 5-25 weight parts relative to 100 weight parts of the reaction balance mixed gas) with the weight ratio of 0.1-10 respectively enter the quench tower 2 from the tower top and the middle part of the quench tower, feed liquid at the tower bottom of the quench tower (the content of aniline is 96-99.9 weight percent) enters a solid-liquid separator 1 through a circulating pump, and clear liquid obtained after catalyst particles are separated is taken as an extracted material aniline removal refining unit, the rest part of the waste water is used as circulating material (the extracted material accounts for 3 to 25 weight percent of the circulating material) and returns to the top of the quenching tower 2 to be used as spraying liquid. The gas phase (wherein the aniline content is not more than 20 wt%) at the top of the quenching tower enters a condenser 3, a noncondensable gas dehydrogenation recovery system at the top of the condenser 3, a condensate de-oiling water separator 4, a crude aniline de-refining unit obtained at the lower layer, and part of aniline-containing wastewater obtained at the upper layer is recycled as a supplementary spray liquid.

The hydrogen heat exchanger 6 is provided with a differential pressure sensor, and the carrier gas pipeline and the pipeline of the solid buffer tank 5 are respectively provided with an interlocking pneumatic valve; when the pressure difference of the hydrogen heat exchanger 6 exceeds a set value (the set value is 1-30kPa), a signal is transmitted to the pneumatic valve through the sensor, the valve is opened, solid particles (the particle size is 0.1-5mm) are added into the solid buffer tank 5 from the top and are sprayed to the top of the hydrogen heat exchanger 6 under the drive of carrier gas, and when the pressure difference is lower than the set value, the valve of the interlocking pneumatic valve is closed in a linkage manner.

The present invention will be described in detail below by way of examples.

In the following examples, alumina, silica and zirconium silicate are all commercially available;

the liquefied recovery rate of aniline was (1-aniline weight in the overhead gas phase/aniline weight in the reaction equilibrium gas mixture) × 100%

Example 1

According to the flow chart shown in fig. 1, the method provided by the invention is adopted to treat the aniline-containing gas, and the specific steps are as follows:

directly feeding reaction equilibrium mixed gas (the temperature is 220 ℃, the aniline content is 66 wt%, the water content is 25.6 wt%, the hydrogen content is 8.4 wt%, and the catalyst particle content is 2600ppm) from the bottom of a quenching tower 2, and spraying aniline-containing wastewater (the aniline content is 4%, the temperature is 20 ℃; the dosage of the supplementary spraying liquid is 20 parts by weight relative to 100 parts by weight of the reaction equilibrium mixed gas) as supplementary spraying liquid from the top of the tower;

leading out the material liquid at the bottom of the quenching tower by a circulating pump to obtain a extracted material and a circulating material (the extracted material accounts for 5 weight percent of the circulating material); the extracted material enters a solid-liquid separator 1 (filter) with the separation precision of 10 mu m, the catalyst particles are separated, the obtained clear liquid (the aniline content is 99.0 weight percent, and the water content is 1.0 weight percent) is subjected to an aniline removal refining unit, and the circulating material returns to a quench tower 2 to be used as spray liquid.

After the equilibrium is reached, the temperature at the bottom of the tower is 113 ℃, and the temperature at the top of the tower is 97 ℃; the gas phase (aniline content 36.4 wt%, water content 53.4 wt%, hydrogen content 10 wt%, nitrogen content 0.2 wt%) at the top of the quenching tower enters a two-stage series condenser 3, the non-condensable gas at the top of the condenser 3 is removed with a hydrogen recovery system, a condensate deoiling water separator 4 is used for performing oil-water separation and then a crude aniline removing refining unit obtained at the lower layer, the upper layer material is aniline-containing wastewater, part of the material is recycled as supplementary spray liquid, and the rest is used for wastewater extraction treatment.

The results show that: the liquefaction recovery of aniline in the quench tower of the reaction gas was about 50%. The device has no blocking phenomenon in the running process.

Comparative examples 1 to 1

Directly feeding reaction equilibrium mixed gas (the temperature is 220 ℃, the aniline content is 66 wt%, the water content is 25.6 wt%, the hydrogen content is 8.4 wt%, and the catalyst particle content is 2600ppm) into a hydrogen heat exchanger, feeding low-temperature reaction gas (the temperature is 120 ℃) at the outlet of the hydrogen heat exchanger into a quench tower from the bottom, spraying crude aniline with the aniline content of 96.5 wt% and the temperature of 20 ℃ from the top of the tower as supplementary spraying liquid, and using 20 parts by weight of the crude aniline relative to 100 parts by weight of the reaction equilibrium mixed gas;

after the equilibrium is reached, the bottom temperature of the quenching tower is 116 ℃ and the top temperature of the quenching tower is 113 ℃. The aniline content in the gas phase at the top of the quenching tower was 63.4% by weight, the water content was 27.7% by weight, and the hydrogen content was 8.9% by weight.

The results show that: the liquefaction recovery rate of aniline in the reaction equilibrium gas mixture in the quench tower is only 9%, and the effect of spraying and condensing and washing solid particles cannot be achieved by using crude aniline as a spraying liquid (the use amount is 20 wt% of the reaction equilibrium gas mixture).

Comparative examples 1 to 2

Directly feeding reaction equilibrium mixed gas (the temperature is 220 ℃, the aniline content is 66 wt%, the water content is 25.6 wt%, the hydrogen content is 8.4 wt%, and the catalyst particle content is 2600ppm) into a hydrogen heat exchanger, feeding low-temperature reaction gas (the temperature is 120 ℃) at the outlet of the hydrogen heat exchanger into the bottom of a quench tower, and spraying supplementary spray liquid (crude aniline with the aniline content of 96.5% and the temperature of 30 ℃) from the top of the quench tower, wherein the use amount of the supplementary spray liquid is 135 parts by weight relative to 100 parts by weight of the reaction equilibrium mixed gas);

the material liquid at the bottom of the quenching tower enters a solid-liquid separator (filter) with the separation precision of 10 mu m through a circulating pump, after catalyst particles are separated out, crude aniline material is extracted from clear liquid according to the proportion of 20 weight percent and is sent to a refining system (98.7 weight percent of aniline and 1.3 weight percent of water), and the rest 80 weight percent of material is returned to the top of the quenching tower to be used as spraying material.

After the balance is achieved, the temperature of the bottom of the quenching tower is 104 ℃, and the temperature of the top of the quenching tower is 96 ℃; introducing the gas phase (aniline content 43 wt%, water content 43.9 wt%, and hydrogen content 13.1 wt%) at the top of the quenching tower into two-stage series condensers, condensing to a liquid-phase material deoiling-water separator at 30 deg.C, separating to obtain a crude aniline refining system as the lower layer, and aniline-containing wastewater as the upper layer; the top of the condenser is provided with a non-condensable gas dehydrogenation gas recovery system.

The results show that: after the device runs for 30 days, the pressure difference of the hydrogen heat exchanger and the condenser is obviously increased, which indicates that the blockage problem of catalyst particles occurs in the hydrogen heat exchanger and the condenser.

As can be seen from comparison between example 1 and comparative example 1-1, the aniline-containing wastewater obtained by using the oil-water separator as the supplementary spray liquid achieves the effects of using the liquid-phase washing gas and trapping the catalyst particles while achieving condensation of the reaction equilibrium gas mixture with a small amount (20 parts by weight of the supplementary spray liquid per 100 parts by weight of the reaction equilibrium gas mixture); in comparative example 1-1, crude aniline of the same weight was used as the makeup spray liquid, and the liquefaction recovery rate of the reaction equilibrium gas mixture in the quench tower was only 11%, which far failed to achieve the effect of condensing and washing the reaction equilibrium gas mixture.

It is understood from a comparison of example 1 with comparative examples 1 to 2 that although the liquefaction recovery of aniline in the quenching tower of the reaction equilibrium gas mixture can be improved by using a larger amount of crude aniline (135 parts by weight of the make-up spray liquid relative to 100 parts by weight of the reaction equilibrium gas mixture) as the make-up spray liquid, the inside of the tube of the hydrogen heat exchanger is clogged.

Example 2

According to the flow chart shown in fig. 1, the method provided by the invention is adopted to treat the aniline-containing gas, and the specific steps are as follows:

directly feeding reaction equilibrium mixed gas (the temperature is 220 ℃, the aniline content is 66 wt%, the water content is 25.6 wt%, the hydrogen content is 8.4 wt%, and the catalyst particle content is 2600ppm) from the bottom of a quenching tower 2, and spraying aniline-containing wastewater (the aniline content is 4%, the temperature is 30 ℃; the dosage of the supplementary spraying liquid is 30 parts by weight relative to 100 parts by weight of the reaction equilibrium mixed gas) as supplementary spraying liquid from the top of the tower;

leading out the material liquid at the bottom of the quenching tower by a circulating pump to obtain a extracted material and a circulating material (the extracted material accounts for 10 weight percent of the circulating material); the extracted material enters a solid-liquid separator 1 (filter) with the separation precision of 10 mu m, the catalyst particles are separated, the obtained clear liquid (the aniline content is 97.3 weight percent, and the water content is 2.7 weight percent) is subjected to an aniline removal refining unit, and the circulating material returns to a quench tower 2 to be used as a spray liquid.

After the balance is achieved, the temperature of the bottom of the quenching tower is 93 ℃, and the temperature of the top of the quenching tower is 74 ℃; the gas phase (aniline content 14.8 wt%, water content 73.3 wt%, hydrogen content 11.7 wt%, nitrogen content 0.2 wt%) at the top of the quench tower enters a two-stage series condenser 3, the non-condensable gas at the top of the condenser 3 is removed from a hydrogen recovery system, a condensate de-oiling water separator 4 is used for performing oil-water separation and then obtaining a crude aniline de-aniline refining unit at the lower layer, the upper layer material is aniline-containing wastewater, part of the material is recycled as supplementary spray liquid, and the rest is used for wastewater extraction treatment.

The results show that: the liquefaction recovery of aniline in the quench tower of the reaction gas was about 80%. The device has no blocking phenomenon in the running process.

As can be seen from comparison between example 2 and example 1, the supplemental spray liquid used in example 2 was higher in amount (30 parts by weight of the supplemental spray liquid was used per 100 parts by weight of the reaction equilibrium gas mixture), and the recovery rate of liquefaction of aniline in the quenching tower was higher; the device runs stably.

Example 3

According to the flow chart shown in fig. 2, the method provided by the invention is adopted to treat the aniline-containing gas, and the specific steps are as follows:

firstly, feeding reaction equilibrium mixed gas (the temperature is 220 ℃, the aniline content is 66 wt%, the water content is 25.6 wt%, the hydrogen content is 8.4 wt%, and the catalyst particle content is 2600ppm) into a hydrogen heat exchanger 6 containing a solid particle injection system for heat exchange; solid particles (alumina, the particle size is 2mm) in the solid particle injection system are added from the top of the solid buffer tank 5 and are injected to the top of the hydrogen heat exchanger 6 under the drive of carrier gas (nitrogen). The solid particle injection system was operated intermittently, once every 24 hours.

Low-temperature reaction gas (the temperature is 115 ℃) with solid particles obtained at the outlet of the hydrogen heat exchanger 6 is fed from the bottom of the quenching tower 2, aniline-containing wastewater (the aniline content is 4%, the temperature is 30 ℃; the dosage of the supplementary spray liquid is 20 parts by weight relative to 100 parts by weight of the reaction equilibrium mixed gas) is taken as supplementary spray liquid, and the supplementary spray liquid is sprayed from the top of the tower;

after being led out by a circulating pump, the material liquid at the bottom of the quenching tower enters a solid-liquid separator 1 with the separation precision of 20 mu m, and catalyst particles are removed through solid-liquid separation, clear liquid (the aniline content is 95.5 weight percent, and the water content is 4.5 weight percent) is obtained, and the clear liquid is divided into extracted material and circulating material (the extracted material accounts for 10 weight percent of the circulating material); the extracted materials are sent to an aniline refining unit, and the circulating materials are returned to the quenching tower 2 to be used as spraying liquid.

After the equilibrium is reached, the temperature at the bottom of the quenching tower is 80 ℃, and the temperature at the top of the quenching tower is 73 ℃; the gas phase (aniline content 14.3 wt%, water content 71.2 wt%, hydrogen content 14.3 wt%, nitrogen content 0.2 wt%) at the top of the quenching tower enters a two-stage series condenser 3, a non-condensable gas dehydrogenation recovery system at the top after condensing to 30 ℃, a condensate de-oiling water separator 4, a crude aniline de-aniline refining unit obtained at the lower layer after oil-water separation, and aniline-containing wastewater obtained at the upper layer, wherein part of the gas phase is recycled as supplementary spray liquid.

The results show that: the liquefaction recovery rate of aniline in the reaction gas in the quenching tower is 85%. In the running process of the device, the pressure difference change of the hydrogen heat exchanger does not exceed 10kPa, which indicates that the hydrogen heat exchanger has no blocking phenomenon.

Comparative examples 2 to 2

The same procedure as in comparative examples 1-2 was followed except that the separation accuracy of the solid-liquid separator was 20 μm.

The results show that: after the device is operated for 15 days, the pressure difference of the hydrogen heat exchanger and the condenser is obviously increased, which indicates that the blockage problem of catalyst particles occurs in the hydrogen heat exchanger and the condenser.

As can be seen from comparison between example 3 and comparative example 1-1, the aniline-containing wastewater obtained by the oil-water separator is used as the supplementary spray liquid, so that the effects of washing the gas with the liquid phase and trapping the catalyst particles are achieved while the condensation of the reaction equilibrium gas mixture is achieved with a small amount (20 parts by weight of the supplementary spray liquid relative to 100 parts by weight of the reaction equilibrium gas mixture); in comparative example 1-1, crude aniline of the same weight was used as the makeup spray liquid, and the liquefaction recovery rate of the reaction equilibrium gas mixture in the quench tower was only 11%, which far failed to achieve the effect of condensing and washing the reaction equilibrium gas mixture.

It is understood from a comparison between example 3 and comparative examples 2-2 that, although comparative examples 2-2 can improve the liquefaction recovery rate of aniline in the quenching tower by using a larger amount of crude aniline (135 parts by weight of the makeup spray liquid per 100 parts by weight of the reaction equilibrium gas mixture) as the makeup spray liquid, catalyst particles are difficult to be completely removed by the solid-liquid separator without a solid particle injection system, the inside of the tubular heat exchanger is clogged, and the apparatus cannot be stably operated for a long period of time.

As is clear from comparison between example 3 and example 1, although the separation accuracy of the solid-liquid separator of example 3 is increased to 20 μm, the apparatus can be stably operated for a long period of time due to the solid particle injection system.

Example 4

According to the flow chart shown in fig. 2, the method provided by the invention is adopted to treat the aniline-containing gas, and the specific steps are as follows:

firstly, feeding reaction equilibrium mixed gas (the temperature is 210 ℃, the aniline content is 66 wt%, the water content is 25.6 wt%, the hydrogen content is 8.4 wt%, and the catalyst particle content is 2600ppm) into a hydrogen heat exchanger 6 containing a solid particle injection system for heat exchange; solid particles (silicon dioxide, the particle size is 2mm) in the solid particle injection system are added from the top of the solid buffer tank 5 and are injected to the top of the hydrogen heat exchanger 6 under the drive of carrier gas (nitrogen). The solid particle injection system was operated intermittently, once every 30 h.

Low-temperature reaction gas (the temperature is 120 ℃) with solid particles obtained at the outlet of the hydrogen heat exchanger 6 is fed from the bottom of the quenching tower 2, aniline-containing wastewater (the aniline content is 3.6%, the temperature is 35 ℃; the dosage of the supplementary spray liquid is 10 parts by weight relative to 100 parts by weight of the reaction equilibrium mixed gas) is taken as supplementary spray liquid, and the supplementary spray liquid is sprayed from the top of the tower;

after being led out by a circulating pump, the material liquid at the bottom of the quenching tower enters a solid-liquid separator 1 with the separation precision of 20 mu m, and catalyst particles are removed by solid-liquid separation, clear liquid is obtained (the aniline content is 98.7 weight percent, and the water content is 1.3 weight percent), and the clear liquid is divided into extracted material and circulating material (the extracted material accounts for 5.5 weight percent of the circulating material); the extracted materials are sent to an aniline refining unit, and the circulating materials are returned to the quenching tower 2 to be used as spraying liquid.

After the balance is achieved, the temperature at the bottom of the quenching tower is 106.5 ℃, and the temperature at the top of the quenching tower is 96.4 ℃; the gas phase (aniline content 41.4 wt%, water content 47.1 wt%, hydrogen content 11.3 wt%, nitrogen content 0.2 wt%) at the top of the quenching tower enters a two-stage series condenser 3, the top is condensed to 35 ℃ and then is subjected to a non-condensable gas dehydrogenation recovery system, a condensate liquid deoiling water separator 4 is subjected to oil-water separation, a crude aniline removing refining unit is obtained at the lower layer, aniline containing wastewater is obtained at the upper layer, and part of the wastewater is recycled as supplementary spray liquid.

The results show that: the liquefaction recovery of aniline in the quench tower was 53% for the reaction gas. In the running process of the device, the pressure difference change of the hydrogen heat exchanger does not exceed 10kPa, which shows that the hydrogen heat exchanger and the condenser have no blocking phenomenon, and the device runs stably.

Example 5

According to the flow chart shown in fig. 2, the method provided by the invention is adopted to treat the aniline-containing gas, and the specific steps are as follows:

firstly, feeding reaction equilibrium mixed gas (the temperature is 220 ℃, the aniline content is 66 wt%, the water content is 25.6 wt%, the hydrogen content is 8.4 wt%, and the catalyst particle content is 2600ppm) into a hydrogen heat exchanger 6 containing a solid particle injection system for heat exchange; solid particles (zirconium silicate, the particle size is 1.5mm) in the solid particle injection system are added from the top of the solid buffer tank 5 and are injected to the top of the hydrogen heat exchanger 6 under the drive of carrier gas (hydrogen). The solid particle injection system was operated intermittently, once every 24 hours.

Low-temperature reaction gas (the temperature is 130 ℃) with solid particles obtained at the outlet of the hydrogen heat exchanger 6 is fed from the bottom of the quenching tower 2, aniline-containing wastewater (the aniline content is 3.6%, the temperature is 40 ℃; the dosage of the supplementary spray liquid is about 25 parts by weight relative to 100 parts by weight of the reaction equilibrium mixed gas) is taken as supplementary spray liquid, and the supplementary spray liquid is sprayed from the top of the tower;

after being led out by a circulating pump, feed liquid at the bottom of a quenching tower enters a solid-liquid separator 1 with the separation precision of 20 mu m, and catalyst particles are removed through solid-liquid separation, clear liquid (the aniline content is 93.5 weight percent, and the water content is 6.5 weight percent) is obtained, and the clear liquid is divided into extracted materials and circulating materials (the extracted materials account for 20.5 weight percent of the circulating materials); the extracted materials are sent to an aniline refining unit, and the circulating materials are returned to the quenching tower 2 to be used as spraying liquid.

After the balance is achieved, the temperature of the bottom of the quenching tower is 76 ℃, and the temperature of the top of the quenching tower is 69 ℃; the gas phase (aniline content is 10.1 wt%, water content is 75.5 wt%, hydrogen content is 14.4 wt%) at the top of the quenching tower enters a condenser 3, the noncondensable gas at the top of the condenser 3 is removed to a hydrogen recovery system, a condensate liquid deoiling water separator 4 is used for performing oil-water separation, a crude aniline removing refining unit is obtained at the lower layer, the upper layer is used for obtaining aniline-containing wastewater, and part of the aniline-containing wastewater is recycled as supplementary spray liquid.

The results show that: the liquefaction recovery of aniline in the quench tower of the reaction gas was 90%. In the running process of the device, the pressure difference change of the hydrogen heat exchanger does not exceed 10kPa, which shows that the hydrogen heat exchanger and the condenser have no blocking phenomenon.

As is clear from comparison between example 5 and example 3, the additional spray liquid used in example 5 was used in a higher amount (25 parts by weight of the additional spray liquid was used per 100 parts by weight of the reaction equilibrium gas mixture), and the recovery rate of the reaction gas in the quenching tower in the liquefaction of aniline was increased; the device runs stably.

Example 6

According to the flow chart shown in fig. 3, the method provided by the invention is adopted to treat the aniline-containing gas, and the specific steps are as follows:

firstly, feeding reaction equilibrium mixed gas (the temperature is 220 ℃, the aniline content is 66 wt%, the water content is 25.6 wt%, the hydrogen content is 8.4 wt%, and the catalyst particle content is 2600ppm) into a hydrogen heat exchanger 6 containing a solid particle injection system for heat exchange; solid particles (alumina, the particle size is 2mm) in the solid particle injection system are added from the top of the solid buffer tank 5 and are injected to the top of the hydrogen heat exchanger 6 under the drive of carrier gas (nitrogen). A hydrogen heat exchanger 6 in the solid particle injection system is provided with a differential pressure sensor, and a carrier gas pipeline and a solid buffer tank 5 pipeline are provided with an interlocking pneumatic valve; the pressure difference setting of the hydrogen heat exchanger 6 was 5 kPa. When the pressure difference of the hydrogen heat exchanger 6 reaches a set value or reaches a set time, the solid particle injection system automatically operates.

Low-temperature reaction gas (temperature of 115 ℃) with solid particles obtained at the outlet of the hydrogen heat exchanger 6 is fed from the bottom of the quenching tower 2, aniline-containing wastewater (aniline content of 4%, temperature of 30 ℃; the amount of the supplementary spray liquid is 20 parts by weight relative to 100 parts by weight of the reaction equilibrium mixed gas) is used as supplementary spray liquid, and the low-temperature reaction gas with solid particles is fed from the top of the tower to the middle of the tower in a weight ratio of 1: 1, respectively spraying;

after being led out by a circulating pump, feed liquid at the bottom of a quenching tower enters a solid-liquid separator 1 with the separation precision of 20 mu m, and catalyst particles are removed through solid-liquid separation, clear liquid (the aniline content is 95.6 weight percent, and the water content is 4.4 weight percent) is obtained, and the clear liquid is divided into extracted materials and circulating materials (the extracted materials account for 10 weight percent of the circulating materials); the extracted materials are sent to an aniline refining unit, and the circulating materials are returned to the quenching tower 2 to be used as spraying liquid.

After the equilibrium is reached, the temperature at the bottom of the quenching tower is 80 ℃, and the temperature at the top of the quenching tower is 73 ℃; the gas phase (aniline content 14 wt%, water content 71.6 wt%, hydrogen content 14.2 wt%, nitrogen content 0.2 wt%) at the top of the quenching tower enters a two-stage series condenser 3, is condensed to a noncondensable gas dehydrogenation recovery system at the top after 30 ℃, is condensed to a condensate de-oiling water separator 4, is subjected to oil-water separation, is subjected to a crude aniline de-aniline refining unit obtained at the lower layer, is subjected to aniline-containing wastewater at the upper layer, and is partially recycled as supplementary spray liquid.

The results show that: the liquefaction recovery of aniline in the quench tower was 88% for the reaction gas. In the process of 1 month operation of the device, the pressure difference change of the hydrogen heat exchanger does not exceed 5kPa, which indicates that the hydrogen heat exchanger and the condenser are not blocked.

As can be seen from comparison between example 6 and comparative example 1-1, the aniline-containing wastewater obtained by the oil-water separator is used as the supplementary spray liquid, so that the effects of washing the gas with the liquid phase and trapping the catalyst particles are achieved while the condensation of the reaction equilibrium gas mixture is achieved with a small amount (20 parts by weight of the supplementary spray liquid relative to 100 parts by weight of the reaction equilibrium gas mixture); in comparative example 1-1, crude aniline of the same weight was used as the makeup spray liquid, and the liquefaction recovery rate of the reaction equilibrium gas mixture in the quench tower was only 11%, which far failed to achieve the effect of condensing and washing the reaction equilibrium gas mixture.

It is understood from a comparison of example 6 with comparative examples 2-2 that, although comparative examples 2-2 can improve the liquefaction recovery rate of aniline in the quenching tower by using a larger amount of crude aniline (135 parts by weight of the makeup spray liquid per 100 parts by weight of the reaction equilibrium gas mixture) as the makeup spray liquid, catalyst particles are difficult to be completely removed by the solid-liquid separator without a solid particle injection system, the inside of the tubular heat exchanger is clogged, and the apparatus cannot be stably operated for a long period of time.

As is clear from comparison between example 6 and example 3, in the case where the supplementary spray liquid in example 6 was sprayed from both the top and middle of the column, the recovery rate of the reaction gas in the quenching tower for liquefying aniline was higher and the effect was remarkable in the same amount as in example 3 (the amount of the supplementary spray liquid was 20 parts by weight based on 100 parts by weight of the reaction equilibrium gas mixture); and the solid particle injection system automatically operates according to a pressure difference set value, so that the operation stability of the device is further improved, and the energy conservation and consumption reduction are facilitated.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.