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It's originally a word document, but it's not too big so I won't upload it. I just copy it here so everyone can understand. This is* * One of the energy-saving measures vigorously promoted. Introduction to the Coal Pulling Process "Plucking" was originally a term in the petroleum processing industry, which means distilling the clear oil component from crude oil. Coal extraction refers to the extraction of gases, liquid fuels and fine chemicals from coal through mild pyrolysis under normal pressure, medium and low temperature conditions, without catalysts and hydrogen. The thermal conversion process of coal is a process involving a series of complex chemical reactions. Coal is mainly used for direct combustion, accounting for about 80% of the total coal consumption, and about half of it is small and medium-sized coal-fired equipment. The main problem is low thermal efficiency. For example, the thermal efficiency of industrial furnaces is only about 40%, and the thermal efficiency of industrial and heating boilers is only about 60%. At the same time, it causes extremely serious environmental pollution. Because small coal-fired equipment has no means of pollution control, its emissions are much higher than those of large-scale combustion equipment. The direct combustion of a large amount of raw coal produces serious pollution such as smoke, SO2, NOx, heavy metals and polycyclic aromatic hydrocarbons. Analyzing the structural composition of coal, the biggest flaw in the utilization of heat energy generated by direct combustion of coal is that this process reduces high-grade energy to extremely low-grade heat energy for utilization. Coal is first thermally decomposed after heating, which is manifested as a cleavage reaction mainly involving the precipitation of small molecular compounds in coal and the bond breaking and decomposition of active functional groups and alkyl side chains. Then, depending on the thermal conversion medium, it can be divided into pyrolysis, gasification or combustion. The organic and inorganic components in coal react according to different conversion methods to obtain different basic products. If pyrolysis will produce gas (pyrolysis gas), liquid (oil) and solid (semi-coke) products ； Gasification produces syngas ； And combustion produces heat. At the same time, its pollutant precursor elements, such as sulfur, nitrogen, aromatic hydrocarbons, etc., will also generate different final products depending on the conversion process. Thermal conversion of coal is a complex process. It not only involves physical and chemical issues in the conversion process, but also involves theoretical issues such as gas-solid two-phase flow. The coal plucking process is developed using downward circulating fluidized bed technology to realize the multi-generation of oil, gas, heat and electricity from coal under mild conditions. Similar to the topping technology in the field of petroleum refining, the coal topping process uses rapid pyrolysis, rapid separation and rapid cooling to recover volatile powder in coal. Powdered coal and hot ash generated from the circulating fluidized bed riser are rapidly mixed in the downcomer, rapidly pyrolyzed, and volatiles are precipitated. ； Rapid separation of precipitated volatile gases and solid particles ； Utilize circulating liquid media and rapid cooling to obtain high value-added hydrogen-rich liquid products - aromatic hydrocarbons, especially some phenols that are currently difficult to directly synthesize and medium hydrocarbons used as liquid fuels ； The semi-coke produced by pyrolysis is burned in the riser to provide heat and generate electricity without affecting its calorific value. And achieve desulfurization and denitrification during the combustion process of circulating fluidized bed boilers to reduce pollutant discharge ； In addition, refractory gases are available for civilian use ； . In order to improve the yield of liquid products in the coal pulling process, the effects of pyrolysis temperature, heating rate, residence time, and reactor structure on the oil production rate were studied. Prove the optimal process parameters and design of this technology, and ultimately realize the industrialization of the coal topping process. The effects of pyrolysis temperature, heating rate and residence time on liquid yield were studied on an 8kg/h down-circulating fluidized bed coal pulling experimental device and a laboratory-scale small device. The results show that about 7% light oil can be obtained, and 2-3% cresol with high added value can be separated. On a thermal experimental device for coal pulling process with a processing capacity of 8 kg/h, Inner Mongolia Huolin River lignite was used as raw material and ordinary river sand was used as solid heat carrier. The influence of reaction temperature and coal particle size on gas, liquid and solid product yield distribution and liquid composition was investigated. The results show that within the experimental temperature range, as the temperature increases, the yield of gas and liquid products increases; the liquid yield decreases with the increase of particle size. When the reaction temperature is 660°C, the particle size of pulverized coal is less than 0.28 mm and the feeding rate is 4.7 kg/h, the yield of light tar (n-hexane soluble matter in tar) can reach 7.5% (dry coal basis, ω), of which phenols account for 57.1%, naphtha (aliphatic hydrocarbons) account for 12.9%, aromatic hydrocarbons account for 21.4%, and polar components and other components account for 8.6%. Experiments have shown that the descending bed is an ideal reactor suitable for the coal pulling process due to the characteristics of gas and solid flowing downward along the gravity field. This post is finally written by * Edited by QIU on 2009-4-10 10:11 ]