Coal processing to upgrade low rank coal having low oil content

摘要

A method of treating untreated low calorific coal containing moisture and organic volatiles includes feeding untreated coal to a dryer, and drying the coal. The dried coal is subjected to a pyrolyzing step where oxygen-deficient gases are brought into contact with the coal, thereby lowering the volatile content of the coal and producing a stream of pyrolysis effluent gases. The pyrolysis effluent gases are subjected to a separation process to separate lean fuel gases from liquids and tars, wherein the separation process removes less than about 20 percent of the pyrolysis effluent gases as the liquids and tars, with the remainder being the lean fuel gases. The lean fuel gases are returned to the dryer combustor, the pyrolyzer combustor, or the pyrolyzer.

主权项

1. A method of treating untreated low calorific coal containing moisture and organic volatiles, the method comprising:
operating a dryer combustor for producing gases for drying coal; feeding untreated coal and the gases for drying coal to a dryer, and drying the coal; operating a pyrolyzer combustor for producing oxygen-deficient gases for pyrolyzing; subjecting the dried coal to a pyrolyzing step in a pyrolyzer wherein the oxygen-deficient gases for pyrolyzing are brought into contact with the coal, thereby producing char having a lower volatile content than that of the untreated coal and producing a stream of pyrolysis effluent gases; subjecting the pyrolysis effluent gases to a separation process to separate lean fuel gases from liquids and tars, wherein the separation process removes less than about 20 percent of the pyrolysis effluent gases as the liquids and tars, with the remainder being the lean fuel gases; and returning the lean fuel gases to one or more of the dryer combustor, the pyrolyzer combustor, or the pyrolyzer, wherein a portion of the lean fuel gases is blended into the oxygen-deficient gases for pyrolyzing.