Learning on potential corrosive environments in advanced biorefineries
Abstract
Advanced biorefining is a versatile concept that promotes the sustainable production of a portfolio of biobased products including biomolecules, biomaterials, bioenergy and energy vectors from various biomass resources and residues. Early development of so-called 1G (first generation) biorefineries that were essentially concentrating on mass production of biodiesel or bioethanol has shown a number of limitations in the related value chains in terms of sustainability issues. Among those issues, a number of corrosion problems have been reported and identified, at least partially understood and sometimes solved. We can quote for example the corrosion of some metallic components of engines due to heat driven conversion of ethanol into acidic species before combustion, the high temperature corrosion in biomass burning furnaces due to the presence of alcali salts as well as stress corrosion cracking in ethanol carbon steel tanks and in pipelines. However no global assessment of corrosion issues in the biorefineries of the future has been performed so far, hence leaving significant interrogation where research efforts have to be deployed to accompany their sustainable implementation. This paper first offers a first overview of the topic from results obtained from the ECORBIO project (for Evaluation of CORrosion in BIOrefineries of the future), the main aim of which is to cover this gap by delivering useful information to process managers, engineering companies and investors for evaluation of corrosion in bioprocesses. The project (Oct 2012 to March 2016) lies on a diversity of scientific approaches comprising: a) literature review b) analysis of accident statistics, exchanges with stakeholders c) testing with existing and purpose developed procedures with a focus on 'biocorrosion', organic acids and ionic liquids, d) learning on a case study in relation with 2G ethanol one pot process . Preliminary results exposed in this paper comprise: a) the analysis of the corrosive environment potentially developed by key microbial products such as organic acids (lactic acid, acetic acid, succinic acid, citric acid....) with sulphuric and distilled water as reference substances for three different grades of steels ; b) corrosive potencies of some imidazolium and phosphonium based ionic liquids that may play a role e.g. in lignocellulosic biomass defragmentation and/or in cellulose dissolution c) first lessons from experience in biorefining and from more general statistics d) first learnings on the pertinence of the C1 test protocol that is used to state whether or not a given substance (e.g. a process juice) is 'corrosive to metals' as an identified dangerous physico-chemical intrinsic property, according to the recently implemented CLP Regulation in the EU (also included in the Globally Harmonised System at UN level).