Method for improving sulfur fixation rate in coal pyrolysis by using ash heat carrier

The invention discloses a method for improving the sulfur fixation rate in coal pyrolysis by using an ash heat carrier. The method comprises the following specific steps: 1, dissolving a water-soluble calcium salt and/or a water-soluble zinc salt in water to prepare a treatment solution, soaking coal ash after combustion in a power plant in the treatment solution for 20-30 minutes, and drying for later use; 2, mixing a certain amount of raw material coal with the treated coal ash, performing pyrolysis under the condition of air isolation, and inhibiting separation of sulfur-containing compound gas in coal pyrolysis to obtain clean pyrolysis gas; and 3, completely soaking pyrolyzed semi-coke or coke in an acid solution for 1-3 hours, dissolving sulfur in the coal out of the acid solution, and washing to remove coal ash mixed in the coal after soaking so as to remove most sulfur in the coal and obtain clean semi-coke or coke. The method provided by the invention can reduce the emission of sulfur oxides in the p