Microwave Desulfurization Of Coking Coal With Additives

With the rapid development of metallurgical industry, expanding of the cokingproduction scale, there is a comparative shortage of high quality coking coal resourcesin our country. At the same time, part of coking coal for the high content of organicsulfur content can’t be used reasonable, so we need find an effective method ofdesulfurization. However, the microwave shows unique advantages in the field of coaldesulfurization technology, for its good selectivity, penetrability and the small damageto coal’s organic matter.Based on microwave desulfurization of coal research, the desulfurization ofXinYu coking coal and LinShu fat coal was studied under the condition of addingadditives with2450MHz microwave devices. The main contents and conclusions areas follows:(1)The microwave desulfurization experiments results of XinYu and LinShu coalwith NaOH, NaCl, KCl, CaBr2, anhydrous ethanol or N-methyl diethanola-mineaqueous solution added, show that the desulfurization effect is best when NaOHsolution added into the two kinds of coal. The sulfur removal rate gradually increases,with the increasing of microwave irradiation time, power, concentration of NaOHsolution and the decreasing of the particle size. While the sulfur removal rateincreases at first and then decreases with the increasing of adding amount of NaOHsolution.(2)With NaOH solution adding, microwave desulfurization experiments of thecoal samples were conducted. The analysis of gaseous sulfur with trace sulfurchromatograph shows that part of the sulfur of the XinYu coal release CS2and H2S,and part of the sulfur of the LinShu coal release CS2, H2S and COS, moreover theconcentration of gaseous sulfur released by LinShu coal is considerably higher thanthat of XinYu coal. After desulfurization the analysis of coal structure with FTIRshow that the content of thiol, sulfide and sulfoxide obviously decreased.(3)In order to find the difference between microwave irradiation andconventional heating, the desulfurization experiments of the coal samples wereconducted with NaOH solution adding by the two ways. The analysis shows thatsulfur removal rate, the weakening of absorption peak and the content of gaseoussulfur with microwave irradiation are higher than that with conventional heating. Theabove analysis illustrates that microwave desulfurization is superior to conventional heating desulfurization.(4) Microwave desulfurization experiments of the acid-treated XinYu coalsamples were conducted. The analysis of gaseous sulfur with trace sulfurchromatograph shows that part of the sulfur in the acid-treated XinYu coal samplesrelease CS2, H2S and COS. The XPS analysis shows that the kinds of organic sulfur inacid-treated XinYu coal are given priority to thiophene which is difficult to removal,also contains a small amount of thiol, sulfide and sulfoxide. After microwaveirradiation, the removal rate of thiophene is less, but thiol, sulfide and sulfoxide aremost removed.