焦煤中添加废塑料和脱硫剂的焦化过程研究

Research on coking process of coking-coal blended with plastic and sulfur sorbent

在模拟焦化室和焦化条件下,进行了焦煤中直接添加废塑料和脱硫剂后的焦化过程的研究,分析了焦化过程中焦炉煤气H2S脱除效果及脱硫剂和废塑料的添加对焦炭硫和锌及其在焦炭中残留率的影响。结果表明,焦煤的焦化过程中,直接添加ZnO、Fe2O3或冶金粉尘(MD)作为脱硫剂,当关键脱硫组分ZnO和(或)Fe2O3与可挥发性硫的摩尔比(nZn+Fe/nS)为1.2时,焦炉煤气H2S脱除效果均较好,塑料本身的热分解使得焦煤中添加质量分数为5%的废塑料后焦炭产率从81.52%降到77.61%;当焦煤中添加质量分数为5%的废塑料,并以ZnO为脱硫剂时,由于塑料中硫的质量分数相对焦煤要高,所以需要增大nZn+Fe/nS到1.7,才能取得较好的煤气脱硫效果,与此同时焦炭中锌和硫的质量分数均有不同程度的增加。

Under the simulated conditions of coking chamber, the coking process of coking coal blended with plastic and sulphur sorbent was investigated. The H_2S removal efficiency of coking oven gas (COG) and the contents of residues of sulphur and zinc in the coke were also analyzed. The experimental results indicate that for the coking process of coking coal blended with ZnO, Fe_2O_3 or metallurgical dusts (MD), the removal efficiency of H_2S in COG was satisfying when the molar ratio of sorbent (ZnO and/or Fe_2O_3) to the volatile sulfur in the mixture of coal and plastic (n_(Zn+Fe)/n_S) is 1.2. The desulfurization activity of MD is relatively lower than that of ZnO and Fe_2O_3. Because of the thermal cracking behavior and chemical composition of plastic, the coke yield decreases from 81.5% for the coking-coal to 77.61% for the coking-coal with 5% of plastic added. However, if 5% of plastic and ZnO are added into the coking-coal, a satisfying removal effect of H_2S in COG can be obtained when n_(Zn+Fe)/n_S is increased to 1.7 due to the relative higher sulphur content in the plastic, while the contents of sulphur and zinc in the coke increase to some extent.