Pre-treatment of water-containing lignite for use in a gasifier operating under pressure

Abstract From the Canadian patent

Water-containing solid fuels particularly brown, coal or lignite, must be dried before conveying to a gasification reactor operating under pressure. A process is provided for treating the coal whereby water or steam is added to the coal to yield a mixture having a ratio of water to coal (computed on a dry basis) of approximately 2.5-3.5 to 1. The coalwater moisture is then maintained at a temperature of approximately 200-300°C and a pressure higher than that of the gasifier and in the range of about 15- 110 bars until the coal has substantially lost its colloidal structure and the water separates from the coal in liquid form. After separation from the water, the coal is transported to the …