Liquefaction of lignohemicellulosic waste by processing with carbon monoxide and water

Abstract

We have liquefied lignohemicellulose, from waste black liquor, by using a carbon monoxide and water process, without using carrier oil or catalyst and aiming to produce heavy oil. Most of the liquefying reactions seem to be essentially complete in about 10 min, under the optimum conditions. Increasing the reaction temperature from 250 to 440°C raises the yield of the heavy oil from 20 to 80%. At relatively low temperatures, the same high yield of the oil was obtained by addition of different alkalis to the reaction medium in a low concentration. With addition of calcium hydroxide at a Ca/C mole ratio of 6 × 10−3 (where Cas moles of added calcium and C is moles of organic carbon in the lignohemicellulose) the yield of the heavy oil was 80%, which was about 49% without any additives and at the same reaction conditions. The grass lignin gave higher yield than the woody lignin, obtained from cotton stalks. For benzene soluble products, which were obtained from liquefaction of lignohemicellulose, the atomic H/C ratio was high and had values of 1.0 to 1.3.