| 摘要 |
PURPOSE:Tar vapor and water vapor are allowed to condense on the surface of dry-distilled low-quality coat batchwise to increase its calorie and simultaneously improve water-proofing properties whereby the moisture absorption and spontaneous ignition are prevented during transportation and storage. CONSTITUTION:Low-quality coal is preliminarily dried with low-temperature heat transfer medium, then high-temperature heat transfer medium is employed to effect drying and dry distillation. The resultant dry-distilled coal is cooled down with a coolant in the same heat exchanger, while the tar vapor and water vapor generated by dry distillation is sent to the other heat exchanger where they are allowed to condense batchwise to coat the surface of the dry-distilled coal. Thus, the low-quality coal is modified. Each process is carried out using 4 or more heat exchangers A, B, C, D by switching with time.
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