Method for preparing raw gas from biomass

The invention discloses a method for preparing raw gas from biomass, which comprises the following steps: mixing biomass and feed coal as a raw material of a gasification furnace, feeding the raw material into a pulverized coal gasification furnace, and carrying out gasification reaction to prepare the raw gas; the raw materials of the gasification furnace comprise biomass, preferable coal, other raw coal and limestone powder; preferably, the Hardgrove grindability index of the coal is greater than 50, the volatile matter content is less than 30%, the ash content is 12-25%, the total content of potassium oxide and sodium oxide in the ash is 1-3%, the silica-alumina ratio in the ash is 1.5-3.5, and the calcium oxide content in the ash is 1-20%; the other raw coals are coal types except the preferable coals. By strictly controlling the mixing proportion of the biomass and the feed coal, the biomass is used as the raw material of the entrained-flow bed pulverized coal gasification furnace, so that the Hardgrove