Coal breaker remaining. The sorting by size is particularly important for anthracite coal. In order to burn efficiently, air must flow evenly around anthracite. Subsequently, most anthracite coal is sold in uniform sizes. In the 1910s, there were six commercial sizes of coal (with the smallest size having three subsets): Coal pieces smaller than in size were considered "culm," and unable to be separated from the impurities (and thus useless). The grade of coal ranged from a low of 5 percent impurities for steam or broken coal to a high of 15 percent for pea-size coal and its subsets. Coal breakers were
Coal gasification has multiple beneficial uses such as aggregate in concrete, aggregate in asphalt for road construction, grit in abrasive blasting, roofing granules, etc. CO is of paramount importance in global climate change. Ash is formed in gasification from inorganic impurities in the coal. Some of these impurities react to form microscopic solids which can be suspended in the syngas produced by gasification. Typically coal contains anywhere from 0.2 to 5 percent sulfur by dry weight, which converts to HS and COS in the gasifiers due to the high temperatures and low oxygen levels. These "acid gases" are removed from the syngas