摘要 |
A method of processing coal to remove sulfur and other contaminants by mixing coal in a solution of aqueous ammonia having a selected concentration range (preferred range of 3%-5%) of ammonia to water in a reaction vessel. The mixing causes the solution to be brought into contact with the surfaces and pores of the coal. The process is monitored to detect when the concentration of aqueous ammonia in the reaction vessel has fallen below the selected range, and aqueous ammonia with an ammonia concentration in or above the selected range is fed into the reaction vessel to return the solution to within the selected range. The cleaned coal may be rinsed and dried, or dried without rinsing to form an ammonia coating on the coal surfaces and pores. Several plant layouts to practice the method are described.
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