A techno-economical comparison of three processes for the production of ethanol from pine

This study comprises a technical and economic comparison of three different processes for the production of fuel ethanol from pine. The processes were based on the same technical and economic assumptions. The main difference between the processes lies in the front end of each process, i.e. in the pretreatment of the raw material and in the hydrolysis of the hemicellulose and cellulose to sugars. The three processes compared are a concentrated hydrochloric acid process, a two-step dilute acid process with sulphur dioxide in the first and hydrochloric acid in the second hydrolysis step, and an enzymatic hydrolysis process, including steam pretreatment. The ethanol production costs found in this study are, excluding the capital costs, 2•43, 1•89 and 1•80 SEK/l, respectively, and including the capital costs 4•22, 4•29 and 4•03 SEK/l, respectively. Based on a sensitivity analysis, it was concluded that none of the processes can be eliminated as less economical than the others.