Definition and classification of coal chemical industry

After entering the 21st century, with the turmoil in the global oil market and the rise in oil prices, coal has received more and more attention as a resource with huge reserves and a potential substitute for oil. The chemical structure of organic matter in coal is a macromolecular structure with aromatic-based fused rings as the unit core, interconnected by bridge bonds, and with various functional groups. fuels and chemicals. The following is the definition and classification of the coal chemical industry compiled by Xiaobian.
Definition of coal chemical industry
Coal chemical industry refers to the process in which coal is used as raw material and chemically processed to convert coal into gas, liquid and solid fuels and chemicals. It mainly includes coal gasification, liquefaction, dry distillation, tar processing and calcium carbide acetylene chemical industry.
Coal chemical industry mainly includes coal gasification, liquefaction, dry distillation, tar processing and calcium carbide acetylene chemical industry. As the world's oil resources continue to decrease, coal chemical industry has broad prospects.
Among the available production technologies for coal chemical industry, coking is the earliest applied process, and it is still an important part of the chemical industry today.
Coal gasification plays an important role in coal chemical industry. It is used to produce various gaseous fuels. It is a clean energy source and is conducive to improving people's living standards and environmental protection. The synthesis gas produced by coal gasification is synthetic liquid fuels, chemical raw materials, etc. raw materials for the product.
Coal direct liquefaction, that is, coal high-pressure hydrogenation liquefaction, can produce artificial petroleum and chemical products. In times of oil shortages, coal liquefaction products will replace natural oil.
Classification of coal chemical industry
Coal chemical industry includes primary chemical processing, secondary chemical processing and deep chemical processing of coal, coal coking, gasification, liquefaction, coal synthesis gas chemical, tar chemical and calcium carbide acetylene chemical and so on. According to the market survey and analysis report of the coal chemical industry released by the China Report Hall, according to the different production processes and products, it is mainly divided into four production chains: coal coking, coal calcium carbide, coal gasification and coal liquefaction. Among them, coal coking, coal calcium carbide, and synthetic ammonia in coal gasification belong to traditional coal chemical industry, while coal gasification to alcohol, ether fuel, coal liquefaction, coal gasification to olefin, etc. belong to the field of modern new coal chemical industry.
Coal chemical production technology types:
1. Coking of coal. The process of isolating coal from air to enhance heat to make it decompose, also known as dry distillation of coal, coking is the earliest and still the most important process. Coal coking products mainly include coke, coal tar (benzene, toluene, etc.), coal furnace gas (hydrogen, methane, ethylene, carbon monoxide, etc.), arginized ammonia water, etc. These products have been widely used in chemical, pharmaceutical, dye, pesticide and carbon industries, and some are even irreplaceable in petrochemical industry, such as pyridinequinoline compounds and many fused ring compounds. Its main product is metallurgical coke.
2. Coal gasification. The thermalization process in which coal converts solid carbon into combustible gas (gas mixture) by the chemical action of gasification agent under high temperature conditions. Air, water vapor, and carbon dioxide are used as gasification agents, and they are heterogeneous with the carbon in coal. reaction. In addition, the gaseous products of thermal decomposition of coal, such as CO2, H2O, and hydrocarbon ash, can also react homogeneously with red-hot carbon. According to the gasification method, the gasification conditions and the properties of the coal are different, and the composition of the gasification gas is also different. According to the characteristics of the gas process in the gas generator, the coal seam can be divided into drying zone, dry distillation zone, reduction zone, hydrogenation zone and ash layer from top to bottom. When heated, water is released and volatilized, and the remaining coke undergoes an oxidation reaction in the reduction zone and the oxidation zone. After coal gasification, crude gas is obtained, and after purification and processing, various chemicals can be obtained. The methods commonly used in coal gasification are: fixed bed atmospheric gasification gas Luqi pressurized gasification gas, Cobbs-Tots entrained bed gasification gas (K-T), Texaco fluidized bed gasification gas (Texaco) , Improved Winkler fluidized bed gasification gas, etc. Coal gasification occupies an important position in coal chemical industry. It is used to produce various gas fuels and is a clean energy source. It is used for city gas and various fuel gases (widely used in machinery, building materials and other industries). The syngas produced by coal gasification is Raw materials for various products such as synthetic liquid fuels (as raw materials for synthetic ammonia, synthetic methanol, etc.)
3. Coal liquefaction. The so-called coal liquefaction is the conversion of organic matter in coal into fluid products, the purpose of which is to obtain and use liquid hydrocarbons to replace petroleum and its products, including direct liquefaction technology and indirect liquefaction technology. The high concentration of engineering technology is the development direction of China's new coal chemical technology and industry. (1) Direct liquefaction of coal. Direct liquefaction of coal was first invented by German scientist F. Bergius in 1913. The main principle is that coal reacts directly with gaseous hydrogen under the action of solvent and high temperature and high pressure, so that the hydrogen content of coal increases, and finally turns into liquid. In 1927, the German fuel company Pier et al. made a section on tungsten sulfide and copper sulfide catalysts. The liquefaction process was divided into two stages: paste phase hydrogenation and gas phase hydrogenation, which solved the engineering problem and built the world's first industrial scale production. 20 sets of direct coal injection units have been built successively. (2) Indirect liquefaction of coal. Indirect liquefaction of coal was first proposed by the Royal German Coal Institute in 1923. The principle is that coal is used as the raw material to be gasified into synthesis gas (CO, H2) first, and then the synthesis gas is used as the raw material to synthesize (F-T synthesis) liquid hydrocarbon products under the action of a catalyst. (Currently, there are only three synthetic liquid fuel plants, SASOL-I, SASOL-II and SASOL-III, which still have coal indirect liquefaction plants in South Africa)
4. Other direct chemical processing of coal. Production of montan wax, sulfonated coal, humic acid and activated carbon. There are still small-scale applications.