RI 2630 Ash Softening Temperatures And Clinkering Of Coals In A Boiler Furnace

"In trying various coals at one of the Government power plants, comparison was made of the ash softening temperature of each coal, with the clinkering tendencies of the coal when burned in the furnace. The proximate analyses, ash softening temperature and plant reports as to clinkering were tabulated. It was desired to bring out any correlation that might appear between the ash softening temperature found in the laboratory, and the clinkering of the ash as found in the boiler furnace.Each coal used was sampled and analyzed, and the standard ash fusion test made. The clinkerring of the coal in the furnace was observed by the furnace operator. The furnace equipment consisted of the ""V"" or Murphy type of stoker with the ordinary fire-brick arch roof. With such arrangement very high furnace temperatures are apt to be produced at the ratings carried at this plant.The softening temperature of ash is defined as the temperature at which small cone of the ash, as tested in the laboratory furnace, has fused down to a spherical lump, The softening interval is the difference between the softening temperature and the temperature at which the first rounding, or bending, of the apex of the cone takes piece. The flowing interval is the difference between the softening temperature and the temperature at which the ash has reached a fluid condition as shown by spreading out over the base in a flat layer.While the analyses of the different samples of the some coal did not vary appreciably, the ash softening temperatures were not always so consistent. It will be noted from the following examples that the ash softening temperatures of different samples of the same coal differ as much as 290° F, Hence, in order to judge this property of a coal, many samples ore desirable, taken from many different shipment."