| To improve the efficiency of coal resources is the main direction of research in the next few decades. Coal pyrolysis-gasification technology in a dual fluidized bed is a combination of coal-oil technology and fluidized bed technology. In this system, coal pyrolysis, partial gasification and combustion processes are taken place sequentially. Volatile in coal is converted into tar or gas, while the semi-coke burned effectively. This is of great value to countries which regard coal as its main energy resource.Based on the origin technology in dual fluidized beds, a new technology is considered. Exploration experiments and cold experiments have been made to optimize the system. In the technology process, part gasification process happens in combustion chamber and pyrolysis process happens in pyrolyzer. The combustion chamber is connected with pyrolyzer by two loop seal of U type. One loop seal is an open valve, the other loop seal is a control vlave.Under the guidance of the technology process, improvements and reconstruction of the test system were made. Parameters of material delivery, operation and pressure balance were fixed.Experiments on several kinds of coal were made on the dual fluidized beds test rig. The total yield of liquid was about 20% under experimental conditions. The pyrolysis efficiency reaches the highest when the volatile of coal is 32%. In the range of 450～850℃of pyrolysis temperature, the pyrolysis products yield increases with temperature, the pyrolysis efficiency reaches the highest in 550℃of pyrolysis temperature. The tar yield reaches the highest in 550℃of pyrolysis temperature, the pyrolysis time has few impact on the pyrolysis process. The proportion of in the pyrolysis gas has a relation of H2>CH4>CO>CO2, the heat value decreases while the gas yields increases with the temperature.Based on the experiments, some kinds of phenomenon of imbalance had been summarized, and the way to deal with it had been point out. |
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