• Energy Research

A conceptual biorefinery process has been designed for the integration of the protein extraction and the ethanol production from brewers’ spent grain (BSG) and palm kernel meal (PKM). The conceptual process is designed for an industrial scale biorefinery annually processing 20 kton dry weight BSG and 50 kton dry weight PKM with 8000 production hours per year and is used to techno-economically analyse the performance. The techno-economic analysis showed that the biorefinery of BSG has a high economic potential with an internal rate of return of 24 %. However, despite the high raw material costs, the biorefinery of PKM still has a positive internal rate of return of 12 %. The presented virtual biorefinery demonstrated the economic potential of integrating the production of a valuable product, like protein powder for food applications, with the production of biofuel, like ethanol, from the remaining biomass, thereby valorising a larger portion of the biomass with the same raw material costs.

Monitoring and control of production processes for biopharmaceuticals have become standard requirements to support consistency and quality. In this paper, a constant specific growth rate in fed-batch cultivation of Bordetella pertussis is achieved by a newly designed specific growth rate controller. The performance of standard control methods is limited because of the time-varying characteristics due to the exponentially increasing biomass and volume. To cope with the changing dynamics, a stable model reference adaptive controller is designed which adapts the controller settings as volume and biomass increase. An important asset of the design is that dissolved oxygen is the only required online measurement. An original design without considering the dissolved oxygen dynamics resulted experimentally in oscillatory behaviour. Hence, in contrast to common believes, it is essential to include dissolved oxygen dynamics. The robustness of this novel design was tested in simulation. The validity of the design was confirmed by laboratory experiments for small-scale production of B. pertussis. The controller was able to regulate the specific growth rate at the desired set point, even during a long fed-batch cultivation time with exponentially increasing demands for substrates and oxygen.

An efficient use of biomass resources is a key element of the bioeconomy. Ideally, options leading to the highest environmental and economic gains can be singled out for any given region. In this study, to achieve this goal of singling out an ideal technology for a given region, biotechnologies are assessed by a combination of techno-economic assessment (TEA) and territorial metabolism life cycle assessment (TM-LCA). Three technology variations for anaerobic digestion (AD) were assessed at two different scales (200 kW and 1 MW) and for two different regions. First, sustainable feedstock availability for two European regions was quantified. Then, the environmental impact and economic potential of each technology when scaled up to the regional level, considering all of the region’s unique sustainably available feedstock, was investigated. Multiple criteria decision analysis and internalized damage monetization were used to generate single scores for the assessments. Preference for the technology scenario producing the most energy was shown for all regions and scales, while producing bioplastic was less preferable since the value of the produced bioplastic plastic was not great enough to offset the resultant reduction in energy production. Assessing alternatives in a regional context provided valuable information about the influence of different types of feedstock on environmental performance.

Effectively collecting and disposing municipal solid waste in Dhaka has become a serious and challenging problem. The principal issues that undermine the city’s waste management measures include limited funds to pay for the daily transportation costs, limited capacity to manage a constant citywide collection effort, and a scarcity of land for the establishment and expansion of landfill sites. Decentralised processing of biodegradable waste of fresh markets by anaerobic digestion is a potential alternative to the current waste disposal system. The feasibility was techno-economically analysed. A conceptual design was set up for a fresh market generating 18 m3 waste per day, representing a medium sized fresh market. The biogas production, the related electricity generation, and required land area were estimated. The techno-economic analyses showed that, compared to the current collection, transport, and landfill costs, the total costs of the anaerobic digestion plant are 24% lower. The transport and landfill costs are strongly reduced. The labour, maintenance, and financing costs of the anaerobic digestion plant are nearly covered by the revenues from the offset of electricity. Moreover, it reduces greenhouse gas emissions and improves the circularity. Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 1355-1358

Bio-based supply chains are by nature complex to optimize. The new logistic concept of integrated biomass logistical center (IBLC) provides us the opportunity to make full use of the idle capacity for a food/feed plant to produce biobased products so that the entire chain efficiency can be improved. Although research has been conducted to analyze the IBLC concept, is yet to be an optimization model that can optimally arrange the activities in the supply chain where an IBLC stands in the middle. To fill the knowledge gap in the literature, this paper makes the first step to develop a MILP model that enables biobased supply chain optimization with the IBLC concept, which supports logistic and processing decisions in the chain. The model is applied in a case study for a feed and fodder plant in Spain where managerial insights have been derived for transferring the plant to a profitable IBLC.

The sustainability and circularity of the production of palm oil can be improved by anaerobic digestion of EFB, MF, and POME. Anaerobic digestion experiments with untreated and steam treated EFB and MF were performed. It was experimentally proven that steam treatment of EFB and MF improves the anaerobic digestibility of these residues. Alternative conceptual palm oil mill set-ups, including anaerobic digestion, were analysed on techno-economic, environmental, and circularity aspects. The biogas from the EFB, MF, and POME can provide enough energy to be self-sufficient in steam and electricity. If the steam boiler runs on biogas instead of biomass, no cyclone and electrostatic filter are required for emission control, which equalizes the fixed capital costs related to a biogas system. Preventing methane emission from open POME ponds drastically decreases GHG emission. Besides, extra revenues can be obtained from surplus electricity. Moreover, the nutrients and recalcitrant organic matter are preserved in the sludge and effluent, which can be returned to the soil of the plantation. Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 589-595

Palm Oil Mill Effluent (POME) is considered a problematic waste, causing pollution problems: greenhouse gas emissions, water pollution with organic material, and nutrient pollution. POME is well suited for treatment in digestion tanks, generating methane for energy production. A technology screening showed membrane technology as the most promising technology for further processing of POME digestate into a mineral concentrate and high quality water. However, a techno-economic evaluation showed that the estimated costs related to further processing of POME digestate are currently higher than the potential savings. Options for cost reduction of the membrane technology and of the handling of the mineral concentrate should be explored. In an optimistic scenario the potential savings exceed the costs. If the concept is further developed, processing of POME digestate can contribute to the economic viability of digestion systems and to reducing the environmental impact of palm oil mills. Proceedings of the 26th European Biomass Conference and Exhibition, 14-17 May 2018, Copenhagen, Denmark, pp. 72-76