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Coal Cascade Utilization

Fundamental Finding on Pyrolysis Reaction Control

 

Coal pyrolysis reactions have to occur first at the molecular level to form radicals and mrther Drimary pyrolysis product via radical stabilization reactions. The primary product contains usually low yield of non-condensable small-molecule gas such as CO,CH4,H2 and CO2. As indicated above by MD simulation,  temperature is the critical parameter affecting the formation of primary product, and high temperamre and quick heating to the coal is the guarantee of high pyrolysis product yield.


The Drimary pyrolysis product has to occur in various secondary reactions during its flowing through the reactor SO that the temperature profiles and mass transfer field characteristics in the reactor have to seriously impact on the secondary reactions of the primary pyrolysis product. This means that the yield and composition of the final pyrolvsis product are closely subject to the “matching conditions” between the secondary reactions and the filed characteristics of flow, transfer and temperature. We have found that, for example, if a reactor has a temperature gradient, the produced pyrolysis tar must have low yield and also high content of heavy spectes when the pyrolysis product flows from low temperature to high temperature in the reactor. This is due to the excessive cracking of pyrolysis product when it passes the zone with gradually higher temperature.

 

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