Production of Semicoke from Colombian Coals in Gasifiers

摘要

We studied coal from Colombia which is classified as grade DG and is characterized by a uniquely low ash content (1.4 percent), a low content of phosphorus (0.003 percent) and mineral impurities, a homogeneous petrographic composition (Vt 77 percent), a low caking capacity (y = 8 mm) and sufficiently high structural and thermal stability.The technology of production of semicoke from Colombian coal in gasifiers was realized in the "Slantsy" plant and the serial industrial processing of coal was implemented.The quality characteristics of semicoke are as follows: very low ash content (1.8-3.7 percent) and phosphorus content (0.002-0.008 percent); high reactivity toward CO_2 (1.2- 1.8 cm~3/(g centre dot s)); high electrical resistivity (330-360 ohm centre dot cm); satisfactory thermal stability (94-96 percent); increased porosity (49-54 percent). Due to these properties the semicoke is a high-quality carbonaceous reducing agent for electrothermic processes.The industrial testing of semicoke in ferroalloy plants of Russia, Kazakhstan and Norway in manufacture of ferrochromium and ferrosilicon instead of 30 - 40 percent of metallurgical coke and in the manufacture of crystalline silicon with complete replacement of charcoal, respectively, has demonstrated the high technological efficiency of its utilization.