ECN publication
Iso-Butanol Platform Rotterdam (IBPR)
Published by: Publication date:
ECN Biomass & Energy Efficiency 12-4-2016
ECN report number: Document type:
ECN-E--16-016 ECN publication
Number of pages: Full text:
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The IPBR consortium demonstrated the technical feasibility of a bio-refinery in the Rotterdam area based on the platform molecule isobutanol. The project encompassed the entire value chain from lignocellulosic biomass up to and including the high value end-products striving for entire biomass valorisation. The feedstock of the envisioned full scale bio-refinery is lignocellulosic biomass consuming 1,000,000 ton/year (dry weight) of it. The bio-refinery is envisioned to operate 8,000 hours per year, a common practise in the petro-chemical industry (the remaining time there is no production, to allow for maintenance). In the process, the biomass is fractionated into three main fractions: cellulose pulp, hemicellulose, and lignin. Isobutanol is produced by fermentation from the carbohydrate containing fractions. The end-products that are studied in the project are: • Glycerol tertiary butyl ether (GTBE), a high value biofuel that can be blended in diesel with proven soot emission reduction for EURO4 and older engine types • Isobutanol-acetone condensate (IAc), a product which after hydrogenation is a high value diesel blending product that can be added to jet fuels • Isobutyl acetate (IBAc), a colourless solvent, that presents good solvency characteristics for polymers, resins, oils and cellulose nitrate and is miscible with all common organic solvents. • Purified lignin from the acetone organosolv, a component suitable for bio-based resins, polyurethanes or other polymers; it can also be used in bunker fuels In this project all individual process steps of the full value chain of the bio-refinery have been proven on lab scale. Furthermore, information is generated as part of the technical, economical and sustainability assessment. Pretreatment • Spruce and poplar were effectively fractionated using ECN patented ketone based Organosolv fractionation technology resulting in near native pure lignins as well as hydrolysable cellulose pulps. • Two 10 kg batches of cellulose were produced which after mild activation were shown suitable to produce sugars. • Mild bleaching treatment significantly increased the rate of glucose formation yielding fermentable sugars within 48 hours corresponding to roughly half the reaction time Hydrolyses • Using a commercial cellulase cocktail 90 g/l resp. 60 g/l glucose was obtained for spruce and poplar. Isobutanol production • Hydrolysates were sucessfully used as substrate for isobutanol production. • Including acetate in the fermentation reduces the number of by-products. • Dewatering using commercial ceramic hybrid sylica membranes (with high stability towards acidity) decreases membrane costs significantly. Isobutyl Acetate and Isobutanol-acetone condensate production • Production of Green Isobutylacetate (IBAc) is feasible at high conversions using esterification and trans esterification reactions and a combination thereof. • Cross condensation of Isobutanol and acetone followed by hydrotreatment give excellent products for drop in fuels for diesel and Jet fuel. Istobutene production • Isobutanol was converted to iso-butene was obtained at commercially viable productivities (WHSV > 10) at high selectivities using commercial catalysts. • 150 mL of isobutanol produced in the project was succesfully converted to isobutene, isolated and used for the production of GTBE. Production of GTBE • GTBE has been successfully produced; production of GTBE is profitable on designed scale of 156 kton/year (even though depending on raw material cost price). • Mixing GTBE in diesel influences fuel hose properties well within maximum range. Lignin • Lignin was demonstrated to be suitable for resins used in plywood and showed promise for the production of asphalt. • The lignin produced is highly reactive as demonstrated by combustion and explosion test. It is therefore less suitable as fuel, but likely more suitable as raw material in the chemical industry. The economics of the full scale bio-refinery were calculated in detail based on a dedicated process design. A feasible plant design has been developed for producing IBAc, GTBE and lignin from wood, with a best-case pay-out time of 6 years. The CAPEX of the various cases ranges between 310 - 400 M€. The OPEX ranges between 530 - 690 M€. The life cycle assessment shows advantages of the bio-based isobutanol platform in comparison to the petrochemical platform. The ‘non-renewable energy use’ is approximately 45% lower in comparison to the petrochemical counterpart. The GHG emissions are up 25% lower for the bio-refinery in comparison to their equivalent fossil systems. For fresh water depletion, savings can be up to 58% in contrast to their petrochemical counterparts. It is recommended to demonstrate the full chain of the bio-refinery at pilot scale. The estimated investment costs for a pilot plant are estimated to be 6.4 M€. This report contains an overview of all results. The underlying full scientific reports are available on request.

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