Title
Novel treatment method for black liquor and biomass hydrolysate with partial wet oxidation
Authors
HASSAN RAJA MUDDASSAR KRISTIAN MELIN SARADA KUPPA JUKKA KOSKINEN MARKKU HURME DANIELA DE KOKKONEN and JUHA KALLAS

Received November 1, 2013
Published Volume 49 Issue 3-4 March-April
Keywords wet oxidation, black liquor, spent liquor, partial wet oxidation, biomass, fuel components, lignin, carboxylic acids, non-wood pulping

Abstract
To reduce greenhouse gas emissions, innovative and sustainable sources of energy, fuel and chemicals are needed. Biomass side streams, such as black liquor and hydrolysate from fiber production, could be used for this purpose. Some feedstocks contain precipitates, such as silicate, which makes the evaporation to the high solid concentration needed for combustion difficult. However, as an alternative, black liquor could be partially wet oxidized to produce carboxylic salts and energy. The objective of this work is to investigate the production of carboxylic acid and hydroxyl acid in partial wet oxidation (PWO) of wheat straw black liquor (WSBL), kraft black liquor (KBL) and hydrolysate (HLP) from pulp bleach and hydrolysate (HLW) from wood under various reaction conditions. Experimental results demonstrate that for WSBL and hydrolysate the concentration of acetate and formate increased significantly in the spent liquor during the treatment.