| Coal still accounts for the subject status in China's primary energy consumption structure. In 2011, coal consumption accounted for about 72.8% of the total primary energy consumption in China. With the development of coal mine's deep mining, the continuous variation of coal seam's quality, and presented a rising trend of coal sulfur content, environment pollution of coal production and consumption is a major concern. Coal desulfurization upgrading has become a focus of attention in academic research communities and coal production units. In order to improve the quality of coal, in order to improve the environmental pollution caused by coal consumption, exploratory study was made for coal desulfurization by microwave radiation.In this paper, coal desulfurization upgrading was studied by microwave radiation, with the coal of different sulfur content (clean coal?raw coal) as the research object, the change of raw coal characteristics and microwave field strength on the influence of coal desulfurization were mainly studied. Exploring the change coal moisture, coal grain size, microwave temperature, temperature gradient, researched their relationship with coal desulfurization; Using orthogonal test design ideas, optimized combination of different levels of the two experimental factors; Exploring effect of coal sample in acidic medium, alkaline medium, oxidizing medium on microwave radiation experiment, studied the effect of different medium on coal desulfurization; And through the SDS616-type sulfur detector, WS-G401 industrial analyzer, HARKE-SPCA contact angle apparatus, and JS94H-type electrophoresis apparatus, tested changes of coal quality index, coal wetting contact angle and Zeta potential value before and after the microwave radiation; By IRAffinity-1 Fourier infrared spectrometer and XRD-6100Lab X-ray diffractometer, tested coal samples' IR and XRD spectrograms, and analyzed microstructure changes of coal sample before and after the microwave radiation. Experiment research got the following main results:(1) With the growth of the clean coal moisture, desulfurization rate curve increased at first, and then decreased, the coal moisture was 10%, and desulfurization rate was 9.80%; With the decrease of the coal grain size, coal desulfurization rate decreased, and then increased, when particle size was less than 5 mm, the desulfurization rate could reach 13.50%; With change of microwave temperature from low to high, coal desulfurization rate increased, and then decreased; With the rising of the temperature gradient, coal desulfurization rate showed increases, then decreases.(2) With the growth of the raw coal moisture, desulfurization rate curve decreased at first, and then increased, the moisture was 16%, and desulfurization rate was 33.74%; With the decrease of the coal grain size, coal desulfurization rate decreased, and then increased, when particle size was less than 5 mm, the desulfurization rate could reach 18.43%; With change of microwave temperature from low to high, coal desulfurization rate increased, and then decreased; With the rising of the temperature gradient, coal desulfurization rate showed increases, then decreases.(3) Through the orthogonal experiment of different sulfur content coal and its results analysis of variance, found the interaction of coal moisture and temperature gradient could improve the effect of coal desulfurization. In the orthogonal test, the desulfurization rate of clean coal could reach 16.80%, the raw coal reached 37.16%.(4) With the increase of acid medium dosage, clean coal desulfurization rate showed decreased, then increased, and then decreased; With the increase of alkaline medium dosage, coal desulfurization rate showed increased, and then decreased; With the increase of oxidation medium dosage, coal desulfurization rate showed increased, then decreased, and then increased.(5) With the increase of acid medium dosage, raw coal desulfurization rate showed decreased, and then increased; With the increase of alkaline medium dosage, coal desulfurization rate showed increased, and then decreased; With the increase of oxidation medium dosage, coal desulfurization rate showed increased, and then decreased.(6) Wetting contact angle of raw coal decreased after microwave radiation; Zeta potential absolute value decreased; IR spectral analysis found that the chemical structure of coal has little change after microwave radiation; XRD spectrum analysis found that chlorite, marcasite (FeS2) crystal minerals disappeared, turned into emery, magnetite mineral crystal. |
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