阅读说明：本技术 一种甲烷氯化物绿色生产的改进工艺 (Improved process for green production of methane chloride ) 是由 杨皓 徐成华 刘建英 田黎霞 王娟芸 于 2019-09-26 设计创作，主要内容包括：本发明公告了一种甲烷氯化物绿色生产的改进工艺,甲醇与氯化氢催化反应生产一氯甲烷,一氯甲烷深度氯化生产二氯甲烷、氯仿作为产品,副产四氯化碳通过精馏分离获得液体,加热气化四氯化碳与新鲜氢气以及循环氢气混合,进四氯化碳转化氯仿反应器,原料气总组分为氢气：四氯化碳=7~12：1,热反应产物与甲醇直接进入二级催化反应器,其中的氯化氢与甲醇催化反应生成一氯甲烷,反应尾气中氯化氢含量降低到1%以下,冷冻分离液化产物,采用变温吸附法净化氯化氢及甲烷氯化物到≤1ppm称为净化尾气,变温吸附解吸气加压送入二级催化反应器,净化尾气加压后经过变压吸附分离甲烷后称为循环氢送入四氯化碳转化氯仿反应器,含少量氢气的甲烷经过脱氯塔合格后作为燃气送燃气系统。(The invention discloses an improved process for green production of methane chloride, which comprises the steps of producing methane chloride by catalytic reaction of methanol and hydrogen chloride, producing dichloromethane and chloroform as products by deep chlorination of methane chloride, separating by-product carbon tetrachloride through rectification to obtain liquid, heating gasified carbon tetrachloride, mixing fresh hydrogen and circulating hydrogen, feeding the mixture into a carbon tetrachloride-to-chloroform reactor, wherein the total composition of raw material gas comprises hydrogen with the weight ratio of carbon tetrachloride =7 ~ 12: 1, directly feeding a thermal reaction product and methanol into a secondary catalytic reactor, wherein the hydrogen chloride and the methanol are subjected to catalytic reaction to generate the methane chloride, the content of the hydrogen chloride in reaction tail gas is reduced to below 1%, freezing and separating a liquefied product, purifying the hydrogen chloride and the methane chloride to less than or equal to 1ppm by adopting a temperature swing adsorption method to obtain purified tail gas, feeding the temperature swing adsorption desorbed gas into the secondary catalytic reactor, performing pressure swing adsorption on the purified tail gas to separate the methane, feeding the methane containing a small amount of hydrogen into the chloroform reactor, and feeding the methane containing a pressure swing adsorption.)

1. An improved process for green production of methane chloride is characterized in that methanol and hydrogen chloride are subjected to catalytic reaction to produce methane chloride, methane chloride and chloroform are produced as products through deep chlorination of methane chloride, a byproduct of carbon tetrachloride is rectified and separated to obtain liquid, the liquid is heated and gasified to obtain carbon tetrachloride, the mixture is mixed with fresh hydrogen and circulating hydrogen and enters a carbon tetrachloride-to-chloroform reactor, the total composition of raw material gas is hydrogen with the ratio of carbon tetrachloride =7 ~ 12: 1, a thermal reaction product and methanol directly enter a secondary catalytic reactor, the hydrogen chloride and the methanol are subjected to catalytic reaction to generate the methane chloride, the content of the hydrogen chloride in reaction tail gas is reduced to below 1%, a liquefied product is subjected to freezing separation, the hydrogen chloride and the methane chloride are purified to the content of less than or equal to 1ppm by adopting a temperature swing adsorption method to obtain purified tail gas, the temperature swing adsorption desorbed gas is pressurized and sent to the secondary catalytic reactor, the purified tail gas is pressurized, then subjected to methane adsorption separation to obtain the circulating hydrogen, and sent to the chloroform reactor.

Technical Field

The invention relates to the fields of organic synthesis, energy conservation and environmental protection, and discloses a method for effectively reducing the emission of gas wastes and reducing the resource consumption.

Background

CN110041162A of Yangxi Lishi culture engineering Co., Ltd discloses a green production process of methane chloride, which comprises a hydrochlorination process, a chlorination process, a refining process, a tail gas absorption process, a liquid chlorine vaporization process, a wastewater treatment process, a tail gas absorption and high-boiling-point substance incineration process and a carbon tetrachloride conversion process. The technology is adopted, and the methane chloride production process is improved through a methane chloride direct supply process, a methane chloride wastewater flash evaporation treatment system, alkali concentration optimization in a refined alkali washing process, recycling of chlorination reaction heat, a carbon tetrachloride-to-chloroform process and tail gas absorption and high-boiling-point substance incineration treatment, so that an energy-saving, green, safe and environment-friendly green production process is achieved, the production cost of enterprises is reduced, and the economic benefits of the enterprises are increased.

CN107876046A of Chengang, etc. of Jiangsu physical culture Limited company announces a high-efficiency catalyst for preparing chloroform by gas-phase hydrodechlorination of carbon tetrachloride, which is mainly characterized in that an active component platinum is distributed on a carrier alumina in a form of thick shell penetration, the catalyst takes noble metal platinum as an active ingredient, the introduction amount of the platinum is 0.1-1% of the total mass of the carrier, the carrier is spherical, strip-shaped or other alumina, and the carrier is pretreated by adopting an organic acid competitive adsorbent, so that the active component platinum is distributed on the carrier in the form of thick shell penetration.

Xuhua CN1701846A of Chengdu organic chemistry Limited company of Chinese academy of sciences, having high catalytic activity and stability and used for gas-phase catalytic hydrodechlorination of carbon tetrachloride fixed bed and containing Pt hollow Al₂O₃A catalyst. The catalyst is simultaneously introduced with metal ions which have a synergistic catalytic hydrodechlorination effect with platinum and chloride ions which are resistant to HCl poisoning, and is activated with air before the catalyst is reduced. The method of the invention can improve the activity and catalytic stability of the catalyst.

It can be seen from the bulletin documents that the primary conversion efficiency of carbon tetrachloride is more important to the industry, the comprehensive utilization of chloroform selectivity and the subsequent conversion tail gas is not important enough, and the utilization rate of hydrogen is not improved more effectively. The utilization rate of hydrogen is only about 10%.

Because hydrogen chloride has toxic action on the catalyst, the hydrogen chloride and methane chloride are removed by washing and alkaline washing, and the comprehensive utilization of the hydrogen chloride and the methane chloride containing water and sodium chloride is difficult.

The hydrogenation tail gas is utilized to produce the methane chloride, the waste gas hydrogen chloride is recycled, the sewage discharge is reduced, and the chlorine element and the hydrogen element are utilized to the maximum extent.

Disclosure of Invention

The invention relates to an improved process for green production of methane chloride, wherein methanol and hydrogen chloride are subjected to catalytic reaction to produce methane chloride, methane chloride and chloroform are used as products, a byproduct of carbon tetrachloride is obtained by rectification and separation, the process is the same as the process part of the previously published patent document, the prior process is that the heated and gasified carbon tetrachloride and fresh hydrogen are directly subjected to chloroform conversion to simultaneously produce methane, the improved process adopts one improvement, the heated and gasified carbon tetrachloride is mixed with fresh hydrogen and circulating hydrogen and enters a chloroform conversion reactor, the total composition of raw material gas is hydrogen, namely, the ratio of carbon tetrachloride =7 ~ 12: 1, the improved process is the second, a thermal reaction product and methanol directly enter a secondary hydrochlorination catalytic reactor, wherein hydrogen chloride and methanol are subjected to catalytic reaction to generate methane chloride, the content of hydrogen chloride in reaction tail gas is reduced to below 1%, the gas circulation ratio is 0 (no circulation) ~ 5, a refrigerated separation liquefied product is sent to an inlet of a deep chlorination process, the last outlet gas of the secondary hydrochlorination catalytic reactor is sent to a purified hydrogen chloride purification process by adopting a temperature swing adsorption method, the hydrogen chloride is reduced to below 1ppm in the reaction tail gas, the purified gas is sent to a secondary hydrochlorination catalytic reactor, the tail gas, the purified gas, the tail gas is sent to a methane gas purification process, and the methane gas is sent to a methane gas purification process of methane gas, and methane conversion process of methane conversion, the methane conversion, and methane conversion process of methane.

The liquid phase rectification after the carbon tetrachloride conversion and the liquid phase rectification in the deep chlorination process are combined into a whole, so that the separation cost is reduced. The separation energy consumption is increased little, the investment is also small, and the added secondary methanol hydrochlorination process mostly eliminates the waste gas hydrogen chloride and changes the waste into the raw material.

Detailed Description