炼焦煤热解转化过程中硫的迁移及分布研究
A Study of Migration and Distribution of Sulfur During Pyrolysis and Conversion of Coking Coal
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摘要: 以马钢常用炼焦煤为例,选取具有代表性的高硫、中高硫、中硫和低硫炼焦煤为研究对象,进行固定床煤热解炭化实验,研究煤热解过程中硫的迁移、分布和脱除规律。结果表明:煤种是影响煤热解硫转化迁移、硫形态分布和脱硫率的关键因素,气肥煤和肥煤较焦煤利于硫化物向气相产物中迁移且占比相近,气肥煤中有更多的硫化物转化迁移至液体产物,肥煤和焦煤均较低且占比接近;脱硫率与煤种紧密相关,顺序为气肥煤>肥煤>焦煤,煤中赋存不同形态硫组分热解转化迁移脱硫率的顺序为硫化物类和硫化铁类硫>砜类硫>亚砜类硫;噻吩类硫和硫酸盐类硫的热解转化迁移脱除难易程度与煤硫含量存在一定关联,高硫煤的噻吩类硫较易转化脱除而硫酸盐类硫较难,中高硫煤的情况却相反。Abstract: Taking the comonly used coking coal of Masteel as an example, the representative coking coals with various sulfur contents were chosen as the object. The fixed-bed coal pyrolysis and carbonization experiment was carried out to study the migration and distribution of sulfur as well as desulfurization rate in the process of coal pyrolysis. The results show that coal type is the key factor affecting the transformation and migration of sulfur, sulfur form distribution and desulfurization rate of coal pyrolysis. Compared with coking coal, gas-fat coal and fat coal favor the transformation of sulfur species into gas phase with similar proportions. More sulfide in gas-fat coal is transformed and migrated to liquid products, and both fat coal and coking coal are low and the proportion is close. The desulfurization rate is closely related to the type of coal, which is in the order of gas-fat coal>fat coal> coking coal. The pyrolysis transformation and migration of different forms of sulfur components in coal are in the order of sulfides and pyrites>sulfones>sulfoxides. The removal of thiophene and sulfates are related with the sulfur content of coal, and the thiophene in high-sulfur coal are relatively easier to be transformed and removed, while sulfates are more difficult, but this is contrary to the case of medium-high-sulfur coal.