Study On Pyrolysis Characteristics Of Low Rank Coal With Gas Heat Carrier And Continuous Pyrolysis System Development

Low rank coal has an important position in coal resource of china. Exploitation of low rank coal has been becoming a hot filed of coal chemical. Base on idea which using high temperature gas from dry quenching as heat carrier and heat sources of pyrolysis process of low rank coal, The pyrolysis characteristics of low rank coal in Montenegro have been studied through XX and adiabatic gas heat carrier pyrolysis reactor to determine the optimal technological parameters of heat carrier pyrolysis. And the material and energy balance of the adiabatic gas heat carrier pyrolysis system is regarded as a basis for the process design. What’s more, the heat transfer and pyrolysis model of the gas heat carrier within the packed bed have been established to obtain the internal temperature distribution of the entire packed beds. Finally, the correlative kinetic parameters have been got through the establishment of appropriate pyrolysis mechanism and model. Aiming to the requirement of amplifying the relevant apparatus parameter of low rank coal heat carrier pyrolysis technology, the continuous pyrolysis device of low rank coal heat carrier pyrolysis has been developed to meet the requirement of the subsequent pyrolysis test of variety lignite coal and optimize the technological parameters of pyrolyisis.1、Using the self-developed 100g adiabatic gas heat reactor and the tar recovery system to research the characteristics of pyrolysis weight loss and tar production of Montenegro coal. The studies have shown that, during the pyrolysis of gas heat, the heat-carrying gas have characteristics of transferring heat by direct collision of coal and carrying the pyrolysis production tar, and the effect of heat transfer is better than that of a single furnace wall reactor, mass transfer process has enhanced significantly. The rate of tar collected by adiabatic gas heat carrier reactor is more 23.22% than that of a single furnace wall reactor. The gas-solid heat transfer of small particle size pyrolysis has focused on the coal material of the entrance, formatting the high-temperature layer, causing the incomplete pyrolysis of coal, so the rate of weight loss and tar yield is low. The increase of gas-solid and the temperature of heat-carrying inlet result in the increase of pyrolysis rate. When the gas-solid ratio is greater than 0.01 L·(g·in)-1, the impact of heat transfer has mitigated, and the weight loss rate and tar yield has stabilized. The optimum conditions of heat-carrying gas pyrolysis is the particle size range from 3mm to 10mm, gas-solid ratio 0.01 L·(g min)-1, the heat carrier gas inlet temperature of 600℃, material thickness 70mm, pyrolysis basically completed the required 30min.2、Compare to the radiation heat transfer, heat carrier has a better heat-transfer rate. The yield of tar and the rate of production gas the temperature have increased with the increase of coal’s temperature, while the semi-coke yield decreased. However the semi-coke yield has decreased, the yield of tar has increased, and the rate of production gas has a increased slightly with the final temperature increased.3、Because the characteristics of fast heat and mass transfer between stream and bed, the Montenegro coal pyrolysis reaction which occurred in heat-gas carrier pyrolysis reactor has conducted step by step, following with the direction of the gas flow, until the pyrolysis is complete.4、The heat transfer model of heat-gas carrier packed bed has been established, and the calculated values which obtained by the partial different equation is correspond with the measured values.By selecting the appropriate mechanism functions and pyrolysis model, the corresponding dynamics parameters have been obtained under the final temperature, regarding to the removal of volatiles which generated from heat-gas carrier low-rank coal pyrolysis.5、When the device has finished, a few hot test have been conducted.1# reactor has reached the requirements of dry design, some of the hot test results have shown that 2# reactor achieve the design requirements basically, and the operating parameters of the hot test meet the requirements of operating parameters.