The Lignol Approach to Biorefining of Woody Biomass to Produce Ethanol and Chemicals

Abstract

Processes that produce only ethanol from lignocellulosics display poor economics. This is generally overcome by constructing large facilities having satisfactory economies of scale, thus making financing onerous and hindering the development of suitable technologies. Lignol Innovations has developed a biorefining technology that employs an ethanol-based organosolv step to separate lignin, hemicellulose components, and extractives from the cellulosic fraction of woody biomass. The resultant cellulosic fraction is highly susceptible to enzymatic hydrolysis, generating very high yields of glucose (>90% in 12-24 h) with typical enzyme loadings of 10-20 FPU (filter paper units)/g. This glucose is readily converted to ethanol, or possibly other sugar platform chemicals, either by sequential or simultaneous saccharification and fermentation. The liquor from the organosolv step is processed by well-established unit operations to recover lignin, furfural, xylose, acetic acid, and a lipophylic extractives fraction. The process ethanol is recovered and recycled back to the process. The resulting recycled process water is of a very high quality, low BOD5, and suitable for overall system process closure. Significant benefits can be attained in greenhouse gas (GHG) emission reductions, as per the Kyoto Protocol. Revenues from the multiple products, particularly the lignin, ethanol and xylose fractions, ensure excellent economics for the process even in plants as small as 100 mtpd (metric tonnes per day) dry woody biomass input a scale suitable for processing wood residues produced by a single large sawmill.

Chemical Pretreatment Methods for the Production of Cellulosic Ethanol: Technologies and Innovations

“…Generally, lower ethanol/water ratios favour hemicellulose hydrolysis and enzymatic degradability of pretreated substrates [151] since ethanol is an inhibitor to the performance of hydrolytic enzymes. Ethanosolv has been explored for the development of proprietary technologies such as the Alcell process which is a sustainable alternative to kraft pulping [152], and the Lignol process-a biorefinery platform that uses aqueous ethanol (50% w/w) for pretreating LB at 200 ∘ C and 400 psi to separate the various components in woody biomass [153,154]. High sugar yields and product recovery have been observed on ethanosolv pretreatment of various materials including hybrid poplar [155] and Japanese cypress [156].…”

Biomass pyrolysis for chemicals

“…In addition, lignin and lignin containing residues are large sidestreams from the pulp-and paper industry and from biorefineries that use the carbohydrate fraction of the biomass, e.g. for the production of bio -ethanol [56,57]. Globally ~ 50 Mt per year of lignin originates from the pulp and paper industry, predominantly from Kraft-, soda-and sulphite-pulping of softwood, hardwood and agricultural residues such as straw, flax and grasses.…”

Overview of Biorefineries based on Co-Production of Furfural, Existing Concepts and Novel Developments

“…The liquor obtained with the organosolv pretreatment is further worked up using wellestablished chemical engineering practices to produce furfural, xylose, acetic acid, lipophylic extractives and lignin, see Figure 6 (Arato 2002;Arato, Pye et al 2005). The philosophy behind such a process scheme is that producing only ethanol is not economically attractive, in particular for the scale of e.g.…”