阅读说明：本技术 对硝基苯甲酰氯残液制备水煤气的方法 (Method for preparing water gas from paranitrobenzoyl chloride residual liquid ) 是由 陈伟 余德平 张金刚 腾岩 王洁 薛攀 周廷廷 于 2019-09-24 设计创作，主要内容包括：本发明公开了一种对硝基苯甲酰氯残液制备水煤气的方法,包括：(1)将残液在一级余热回收器内汽化的步骤；(2)将汽化后的残液蒸汽在等离子裂解管式反应器内进行裂解的步骤；(3)将步骤(2)的裂解气在二燃室燃烧的步骤；(4)将步骤(3)的裂解气依次经过一级余热回收器、二级余热回收器、水洗塔、碱洗塔后,尾气经烟囱排放的步骤。本发明采用环保的等离子系统进行残液的处理,该系统是一套密封循环和非焚化的过程,利用高能量密集的等离子场将废弃物的化学键分解并使其重组,转化成有价值的商品,无二噁英生成,并可以做到污染物的零排放。(The invention discloses a method for preparing water gas from paranitrobenzoyl chloride residual liquid, which comprises the following steps: (1) vaporizing the residual liquid in a primary waste heat recoverer; (2) cracking the vaporized residual liquid steam in a plasma cracking tubular reactor; (3) burning the pyrolysis gas in the step (2) in a second combustion chamber; (4) and (4) sequentially passing the cracked gas in the step (3) through a primary waste heat recoverer, a secondary waste heat recoverer, a water scrubber and an alkaline scrubber, and then discharging tail gas through a chimney. The invention adopts an environment-friendly plasma system to treat the residual liquid, the system is a set of sealed circulation and non-incineration process, and a high-energy dense plasma field is utilized to decompose and recombine chemical bonds of wastes and convert the chemical bonds into valuable commodities without generating dioxin, and zero emission of pollutants can be realized.)

1. The method for preparing water gas from paranitrobenzoyl chloride residual liquid is characterized by comprising the following steps:

(1) vaporizing the residual liquid in a primary waste heat recoverer;

(2) cracking the vaporized residual liquid steam in a plasma cracking tubular reactor;

(3) burning the pyrolysis gas in the step (2) in a second combustion chamber;

(4) and (4) sequentially passing the cracked gas in the step (3) through a primary waste heat recoverer, a secondary waste heat recoverer, a water scrubber and an alkaline scrubber, and then discharging tail gas through a chimney.

2. The method for preparing water gas from paranitrobenzoyl chloride residual liquid according to claim 1, wherein in the step (1), the primary waste heat recoverer is connected with the secondary combustion chamber, pyrolysis gas discharged from the secondary combustion chamber supplies heat to the primary waste heat recoverer, and the residual liquid is heated and vaporized.

3. The method for preparing water gas from paranitrobenzoyl chloride residual liquid according to claim 1, wherein the residual liquid after vaporization in step (2) is directly sprayed onto a plasma torch of a plasma cracking tubular reactor, the inner flame temperature of the plasma torch is higher than the outer flame temperature, the carrier for plasma arcing is superheated steam, and the superheated steam is supplemented into the outer flame section of the plasma torch.

4. The method for preparing water gas from paranitrobenzoyl chloride raffinate according to claim 1, wherein in step (3), the temperature of the gas inlet end in the secondary chamber is 1500 ℃, and the temperature of the gas outlet end in the secondary chamber is 1100 ℃.

5. The method for preparing water gas from paranitrobenzoyl chloride residual liquid according to claim 1, characterized in that in the step (4), the secondary waste heat recovery device is externally connected with a water vapor pipe, high-temperature flue gas discharged from the secondary combustion chamber is subjected to primary heat exchange with the residual liquid in the primary waste heat recovery device, enters the secondary waste heat recovery device to perform secondary heat exchange with water vapor, and the water vapor is heated and heated to serve as a plasma arcing carrier and is supplemented into a plasma cracking tubular reactor.

6. The method for preparing water gas from paranitrobenzoyl chloride residual liquid according to claim 1, wherein in the step (4), the gas discharged from the secondary waste heat recovery device is washed by a water washing tower to remove part of acid components, then enters an alkaline washing tower to be subjected to alkaline washing, the water vapor generated in the alkaline washing tower is introduced into a water vapor pipe externally connected with the secondary waste heat recovery device, and the water gas obtained after the alkaline washing tower is discharged from a chimney.

7. The method for preparing water gas from paranitrobenzoyl chloride raffinate according to claim 6 wherein an air inlet valve is also provided on the water vapor line.

Technical Field

The invention relates to a method for preparing water gas from paranitrobenzoyl chloride residual liquid.

Background

The paranitrobenzoyl chloride is an important intermediate for synthesizing vitamin medicinal products such as folic acid, procaine hydrochloride, N-p-aminobenzoyl-L-glutamic acid and the like, and is also widely applied to the production of pigments and color developers. Particularly, in recent years, with the rise of the feed industry and the development of the information industry, the dosage of the paranitrobenzoyl chloride is increasing.

The common synthetic method is that the paranitrobenzoic acid and thionyl chloride are in reflux reaction under the action of a catalyst or the paranitrobenzoic acid and phosphorus trichloride are introduced to react under the condition that carbon tetrachloride is used as a solvent to prepare the compound.

No matter which synthetic route is adopted, the finally obtained product needs to be distilled and purified, materials such as p-nitrobenzoic acid and the like which are not completely reacted can generate certain condensation reaction in the heating and distilling process to generate macromolecular substances, and meanwhile, a certain amount of p-nitrobenzoyl chloride product remains at the bottom of the kettle to form organic residual liquid. The organic residual liquid has complex composition, strong corrosivity and instability, and can generate a large amount of toxic and harmful media such as hydrogen chloride and the like through chemical reaction when meeting water and even moist air. The residual liquid cannot be treated by a physical and common chemical method, and can only be treated by burning, but because a large amount of chlorine and oxygen exist in the molecular structure, and the burning temperature can only reach 1200 ℃, harmful substances such as dioxin and the like are easily formed in the burning process, and serious damage can be caused to human bodies and the environment.

Disclosure of Invention

In order to overcome the defects, the invention provides a method for preparing water gas from paranitrobenzoyl chloride residual liquid which can generate water gas to be recycled as energy and can not generate dioxin, and the method comprises the following steps:

(1) vaporizing the residual liquid in a primary waste heat recoverer;

(2) cracking the vaporized residual liquid steam in a plasma cracking tubular reactor;

(3) burning the pyrolysis gas in the step (2) in a second combustion chamber;

(4) and (4) sequentially passing the cracked gas in the step (3) through a primary waste heat recoverer, a secondary waste heat recoverer, a water scrubber and an alkaline scrubber, and then discharging tail gas through a chimney.

Preferably, the first-stage waste heat recoverer in the step (1) is connected with the second combustion chamber, pyrolysis gas discharged from the second combustion chamber supplies heat to the first-stage waste heat recoverer, residual liquid is heated and vaporized to 300 ℃, and residual liquid steam can be cracked more quickly and fully after entering the plasma cracking tubular reactor.

Preferably, the raffinate after vaporization in step (2) is directly sprayed onto a plasma torch of a plasma cracking tubular reactor, the inner flame temperature of the plasma torch is higher than the outer flame temperature, the inner flame temperature is 7000 ℃, the outer flame temperature is 3000 ℃, in order to obtain CO and H₂The carrier for plasma arcing is superheated steam, and the superheated steam is supplemented into the outer flame section of the plasma torch. The temperature in the plasma cracking tubular reactor is distributed in five sections, the temperature of the five sections from the inner flame of the plasma torch to the gas outlet end is 7000 ℃, 5000 ℃, 3000 ℃, 2000 ℃ and 1500 ℃ in sequence, the electric arc generated by the thermal plasma discharge generates radiant heat, convection heat and heat transfer caused by electrons, all organic matters can be completely decomposed within 0.01-0.05 second at the temperature, the 1500 ℃ cracking gas is directly introduced into a secondary combustion chamber, and the cracking gas comprises CO and H₂And a small amount of carbon black, CO₂、H₂O、NO₂、CL₂And the like.

Preferably, in the step (3), the temperature of the air inlet end in the secondary combustion chamber is 1500 ℃, the temperature of the middle section is 1200 ℃, the temperature of the air outlet end is 1100 ℃, and the retention time of the pyrolysis gas in the secondary combustion chamber is more than 2s, so that the pyrolysis gas is further fully burnt.

Preferably, the secondary waste heat recovery device in the step (4) is externally connected with a water vapor pipe, high-temperature flue gas discharged from the secondary combustion chamber is subjected to primary heat exchange with residual liquid in the primary waste heat recovery device, enters the secondary waste heat recovery device to perform secondary heat exchange with water vapor, heats the water vapor to 300 ℃, and then is used as a carrier for plasma arcing to be supplemented into an outer flame of a plasma torch in the plasma cracking tubular reactor. After the pyrolysis gas is subjected to two-stage waste heat recovery, the temperature is rapidly reduced from 1100 ℃ to 200-350 ℃.

Preferably, the gas discharged by the secondary waste heat recovery device in the step (4) is washed by a water washing tower to remove part of acid components and then enters an alkaline washing tower for alkaline washing, a sodium hydroxide solution with the concentration of 25% is adopted in the alkaline washing tower, the acid components in the pyrolysis gas are neutralized with alkaline liquor, water vapor generated by the alkaline washing tower is introduced into a water vapor pipe externally connected with the secondary waste heat recovery device after being detected to be qualified through tail gas, and CO and H are obtained after the alkaline washing tower₂And discharging the water gas from a chimney, and recycling the water gas as energy. Hydrochloric acid collected from the water scrubber can be sold as a byproduct, and salt collected from the caustic scrubber is evaporated and then treated as a general waste. The amount of the water vapor introduced into the secondary waste heat recoverer can be controlled through tail gas detection, and further O is controlled₂Such that carbon black formed by cracking the raffinate forms CO instead of CO₂。

Preferably, the steam pipe is further provided with an air inlet valve, and when the amount of steam after the alkaline tower is small, steam can be separately introduced.

The invention has the beneficial effects that:

the invention adopts an environment-friendly plasma system to treat the residual liquid, the system is a set of sealed circulation and non-incineration process, and a high-energy dense plasma field is utilized to decompose and recombine chemical bonds of wastes and convert the chemical bonds into valuable commodities without generating dioxin, and zero emission of pollutants can be realized.

Drawings

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic of the present invention.

Detailed Description

The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic views illustrating only the basic structure of the present invention in a schematic manner, and thus show only the constitution related to the present invention.

As shown in figure 1, the method for preparing water gas from paranitrobenzoyl chloride raffinate comprises the following steps:

(1) heating the residual liquid in a first-stage waste heat recoverer, raising the temperature and vaporizing the residual liquid to 300 ℃;

(2) and (3) directly spraying the vaporized residual liquid onto a plasma torch of the plasma cracking tubular reactor, wherein the inner flame temperature of the plasma torch is higher than the outer flame temperature, the inner flame temperature is 7000 ℃, the outer flame temperature is 3000 ℃, and in order to obtain CO and H2, the carrier for plasma arcing adopts superheated steam which is supplemented into the outer flame section of the plasma torch. The temperature in the plasma cracking tubular reactor is distributed in five sections, the temperature of the five sections from the inner flame of the plasma torch to the gas outlet end is 7000 ℃, 5000 ℃, 3000 ℃, 2000 ℃ and 1500 ℃ in sequence, the electric arc generated by the thermal plasma discharge generates radiant heat, convection heat and heat transfer caused by electrons, all organic matters can be completely decomposed within 0.01-0.05 second at the temperature, the 1500 ℃ cracking gas is directly introduced into a secondary combustion chamber, and the cracking gas comprises CO and H₂And a small amount of carbon black, CO₂、H₂O、NO₂、CL₂And the like;

(3) further burning the pyrolysis gas in the step (2) in a second combustion chamber, wherein the temperature of the air inlet end in the second combustion chamber is 1500 ℃, the temperature of the middle section in the second combustion chamber is 1200 ℃, the temperature of the air outlet end in the second combustion chamber is 1100 ℃, and the retention time of the pyrolysis gas in the second combustion chamber is more than 2s, so that the pyrolysis gas is further fully burned;

(4) the pyrolysis gas discharged from the secondary combustion chamber is subjected to two-stage waste heat recovery, and is firstly introduced into a primary waste heat recoverer, and the high-temperature pyrolysis gas enters the primary waste heat recovererSupplying heat, heating the residual liquid and vaporizing to 300 ℃, so that the residual liquid steam can be cracked more quickly and fully after entering the plasma cracking tubular reactor; then a secondary waste heat recoverer is introduced, a water vapor pipe is connected outside the secondary waste heat recoverer, high-temperature flue gas discharged by a secondary combustion chamber is subjected to primary heat exchange with residual liquid in a primary waste heat recoverer, then enters the secondary waste heat recoverer to perform secondary heat exchange with water vapor, the water vapor is heated to 300 ℃ and then serves as a plasma arcing carrier to be supplemented into an outer flame of a plasma torch in a plasma cracking tubular reactor, and the temperature of pyrolysis gas is rapidly reduced to 200-350 ℃ from 1100 ℃ after the pyrolysis gas is subjected to two-stage waste heat recovery; gas discharged by the secondary waste heat recovery device is washed by a water washing tower to remove part of acid components and enters an alkaline washing tower for alkaline washing, a sodium hydroxide solution with the concentration of 25% is adopted in the alkaline washing tower, the acid components in the pyrolysis gas are neutralized with alkali liquor, water vapor generated by the alkaline washing tower is led into a water vapor pipe externally connected with the secondary waste heat recovery device after being detected to be qualified through tail gas, and CO and H are obtained after the alkaline washing tower₂And discharging the water gas from a chimney, and recycling the water gas as energy. Hydrochloric acid collected from the water scrubber can be sold as a byproduct, and salt collected from the caustic scrubber is evaporated and then treated as a general waste. The amount of the water vapor introduced into the secondary waste heat recoverer can be controlled through tail gas detection, and further O is controlled₂Such that carbon black formed by cracking the raffinate forms CO instead of CO₂。

The invention adopts an environment-friendly plasma system to treat the residual liquid, the system is a set of sealed circulation and non-incineration process, and a high-energy dense plasma field is utilized to decompose and recombine chemical bonds of wastes and convert the chemical bonds into valuable commodities without generating dioxin, and zero emission of pollutants can be realized.

In light of the foregoing, it is to be understood that various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.