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New technology and strategy for a large and sustainable deployment of second generation biofuel in rural areas

Periodic Reporting for period 3 - BABET-REAL5 (New technology and strategy for a large and sustainable deployment of second generation biofuel in rural areas)

Reporting period: 2019-02-01 to 2020-01-31

The business model currently developed for the production of 2G ethanol is large plants with annual production capacities up to 100,000 m3 which require high capital investment and huge amounts of lignocellulosic biomasses (up to 200-300,000 t per year). With such conditions, opportunities for a large deployment of plants are scarce in Europe. One of the main barriers for 2G ethanol is the requirement of a pretreatment of the lignocellulosic matrix to facilitate the access of enzymes to the polysaccharides. This step is a complex operation which increases the capital and operational expenditures, and the environmental impact.
The main concept of the project BABET-REAL5 relies on industrial units using small biomass feedstock, more favourable for regions that cannot provide big amounts of concentrated biomasses and for rural development, decentralized energy production & the autonomy of the territories. The objectives of the project are threefold: 1) Evaluate the techno-economic and environmental performances at small industrial scale based on new pretreatment and bioconversion processes, 2) Identify biomass feedstock with sustainable supply conditions and 3) Evaluate the viability of business cases in different countries.
A new process for the pretreatment of the biomass in a twin-screw extruder was developed during the project. The pretreated biomass is directly transferred to a bioreactor ready for simultaneous saccharification of the polysaccharides, and co-fermentation of the produced monomers sugars. This 2 stage set-up is the most integrated and compact solution for the production of 2G bioethanol from lignocellulosic biomass.
The techno-economic and environmental performances of a plant processing 30,000 tons dry biomass per year was evaluated for 5 business cases in France, Germany, Argentina, Uruguay and Mexico using different biomasses. Under the current economic conditions in the different investigated countries, the deployment of plants processing such small quantity of biomass can be viable.
Several biomasses were processed: Barley Straw (BS), Sweet Corn Cob (SCC), Blue Agave Bagass (BAB), Wheat Straw (WS), Sugarcane Crop Residues (SCR), Eucalyptus Forest Residues (EFR) and Corn Stover (CS). The sugar and ethanol productions are mainly dependent on the pretreatment efficiency, the solid loading in the bioreactor, and the contents of polysaccharides in the biomass. BS, BAB and SCC present the best results. The set objectives for hydrolysis and fermentation yields and ethanol concentration are reached. For WS and CS, fermentation yields reach the objective but the hydrolysis yields need to be improved with further experiments. SCR and EFR are more recalcitrant biomasses to the pretreatment due to high contents in lignin and minerals respectively.
The scaling up of the pretreatment and bioconversation processes to TRL5 is successful at both laboratory and pilot scales. The Simultaneous Saccharification and Co-fermentation strategy is successful with prompt consumption of sugars and production of ethanol. The Co-fermentation of hexose and pentose sugars is reached with commercial yeast and the new engineered yeast strain developed during the project.
An industrial plant and a numerical model for simulations at industrial scale were designed for the techno-economic and environmental evaluations and the life cycle assessments were performed in the perimeter field to tank. All the by-products obtained in the production chain are valorised: liquors produce biomethane through anaerobic digestion, lignin produced heat for the processes as fuel for the boiler, remaining organic and mineral matters in the digestate are conditioned as exportable pellet fertilisers and biogenic carbon dioxide from fermentation and biogas purification recovered and valorised for exportation. Several production scenarios were investigated with exportation of biomethane or electricity/heat in the case of cogeneration. This choice of products and scenarios allows adapting the plant model to the national economic and market conditions of the business cases.
Best lignocellulosic biomass feedstock have been identified for all business cases: CS in France, WS in Germany, SCR in Argentina, EFR in Uruguay and BAB in Mexico, and best localisation for industrial plants have been defined, generally in the centre of the biomass catchment areas (50km radius). Under such production conditions and the current economic hypothesis for the purchasing of goods and selling of the products, small-scale plants processing 30,000 tons biomass per year can be economically profitable. The environmental performances are within the set targets for the energy efficiency (twice more energy produced than consumed) and for the carbon foot print (33 gequivalent CO2/MJ produced), except for Argentina where the GHG impact of electricity from fossil origin is high and for Uruguay where harsher conditions for the pretreatment of the biomass are required.
The main results of the project have been presented in the countries of the business case in dedicated workshops with public audiences composed of national experts and stakeholders in the areas of biofuel/bioenergy. Three business cases are most favourable for the implementation of pilot plants after the project.
Currently, the economic and environmental viability of 2G bioethanol production from lignocellulosic biomass at large industrial scale has not been demonstrated. The new processes and production strategy developed and evaluated during the project bring hopes that favourable economic and environmental performances can be obtained at small-industrial scale. With such a business model realistic biomass feedstock (≥ 30,000 tons per year in 50km radius) in Western Europe, can be exploited. This perspective allows the deployment of biofuel production units with a territorial coverage favourable to the circular economy and autonomy of the regions.
In all the studied business cases except in Uruguay, the products can be exported to distributors located in the region. Biomethane can be injected in the network or exported compressed to car/bus fillings stations. Electricity can be injected in the network or recycled in the plant or used by near-by industrial sites. The fertilisers can be distributed by the local cooperatives to the farmers or sent to local distributors. The pure carbon dioxide can be exported to local users like breweries, wine makers, green houses or logistic/agro-industrial companies using CO2 as cooling gases.
New direct and indirect jobs can be created at local level to run the plants and for the harvesting of the biomass and transportation of goods. The building of the plant can give work to local civil engineering companies and to local/national/European companies specialised in the design/engineering, manufacturing and maintenance of equipment for the chemical and biochemical industry (tanks, reactors, boilers, dryers, distillation columns, pumps, pipes, valves, electrical cabinets, sensors....). Most of the processes in the plant are automated and require a good educational level in process engineering, chemistry and biochemistry at operator, technician and engineer levels. The purchasing of the imported goods can generate additional revenue for the suppliers of biomass (the farmers) and chemical products, and the transport companies.
Progress review meeting at Montevideo with USAB members
TRL5 pilot scale equipment set-up at INPT
TRL5 lab scale equipment set-up at CIEMAT
TRL5 lab scale equipment set-up at INPT