Preliminary Experiment Research On Microwave Pyrolysis Of Zhundong Coal

Coal has been the main energy in our country, this state probably will notchange in the future for a long time.But as the global environmental problems havebecome increasingly prominent, clean use of coal will be more and more attentionalby people. In recent years, the gradual rise of the microwave heating theory has beenapplied in areas such as biomass pyrolysis and organic wastes pyrolysis. However,studies of microwave pyrolysis of coal is rare. Because of the unique advantages ofmicrowave heating, microwave pyrolysis of coal could achieve the clean use of coal.It is researched that temperature characteristics of raw coal and semi-coke inthis paper. By analyzing the heating process of coke mixed materials which isadding into semi-coke of mass fraction of10%and X-ray diffraction of differentfinal temperature coke, it is discussed the heating principle of coke mixed materialsin the microwave field and verified the heating characteristics of integrity of themicrowave. It is also researched the influence of the material particle size and typeto affect heating process of microwave. The results showed that semi-coke can beused as early microwave absorber to heat raw coal. After raw coal reachingpyrolysis temperature, it possessed absorbing capacity and accelerated the pyrolysisprocess. With pyrolysis temperature increasing, polycondensation reacts andaromatic carbon layer net plane diameter and quantity increase, and there is anincrease in the number of free electrons, resulting in raw coal absorbing capacityenhancement. Particle size has little effect to semi-coke warming. With decreasingparticle size, coal mixture heating rate increases.Then, the coal discharge phenomena in microwave field was studied.Microwave discharge mechanism of the pyrolysis process of coal was discussed.The influence law of semi-coke content, particle size, coal type on microwavedischarge was studied. The impact of discharge on the heating process was analyzed.The results show that: When using semi-coke, the discharge phenomenon wasobvious, which is the combined impact of tip structure and internal free electron. Innormal condition, coal does not discharge, however, with the pyrolysis temperatureincreasing, the coal gradually gain discharge capacity. The larger particle size, themore intense the discharge phenomena was. The smaller, the more the dischargepoints were. Datong semi-coke have more intense discharge phenomena thanZhundong semi-coke.Finally, preliminary study of Zhundong coal pyrolysis gas phase productprecipitation process in microwave field was conducted. The influence law of semicoke content, particle size, as well as three kinds of catalyst CuO、CaO、K2CO3on the precipitation process of CO2, CO, CH4and H2was studied. The results show that:with the increase of mass fraction of semi-coke and the decrease of particle size,four kinds gaseous products peak appeared ahead of time and the yield increased.Adding three kinds of catalyst had no obvious effect on the four gas production, butthe gaseous products peak appeared ahead of time.