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Abstract This paper addresses the techno-economic, energetic and environmental assessment of the indirect and direct production of bioenergy using Pinus patula (PP) as raw material. Ethanol and synthesis gas are evaluated as main products through biochemical (fermentation) and thermochemical (gasification) routes, respectively. The complete characterization of the raw material was performed aiming to determine the chemical, proximate and elemental composition of the PP that is used as starting point for the simulation procedure. Mass and energy balances were obtained from the simulation of both processes using the software Aspen Plus v9.0. Different economic criteria such as Net Present Value (NPV) and Payback Period (PBP) were used to determine the profitability of both processes. The overall energy efficiency was calculated considering the relation between the energy content of the products and the energy content of the inputs (raw materials and utilities). The environmental assessment involves an attributional life-cycle assessment (LCA) of different systems such as seedlings production, PP cultivation, harvesting and collection, and the evaluated processes using a cradle-to-gate approach. As a result, the production of ethanol evidenced a low production cost (0.549 USD/L), higher energy efficiency (45.1%) and higher CO 2 emissions (0.17 kg per MJ EtOH) in comparison to the biomass gasification. Highlights • Pinus Patula as a potential raw material for direct and indirect bioenergy production. • Steam explosion linked to SSF make the ethanol production a profitable process. • Clear energy policies are required to improve the feasibility of biomass gasification. • The conversion of syngas in electricity has a negative effect on the energy efficiency. • High energy needs in the biochemical route contribute to the high environmental impact. [ABSTRACT FROM AUTHOR]

Moving from fossil‐based economies to bio‐based economies is one of humanity's most important necessities. Bio‐based economies are sustainable alternative ways to obtain chemicals, materials, and energy, and biorefineries have been proposed as promising technological schemes for this purpose. However, the economic performance of biorefineries is strongly related to the scale of the process, as different elements (energy consumption, equipment cost, etc.) vary to different degrees when the scale varies. This situation shows the importance of evaluating the performance of the biorefinery at different scales (analysis of scale) from the design stages. The problem with the analysis of these scales is that there is no unanimous definition of 'scale' and the term is used imprecisely to refer to the raw material or product. Taking this into consideration, this work proposed a strategy for determining the Minimum Processing Scale for Economic Feasibility (MPSEF) and identifying the minimum scale at which a given biorefinery can operate. As study cases, three different biorefineries, based on different raw materials (cocoyam, Andes berry, and coffee cut stems) were used to exemplify the applicability of the design strategy. The MPSEF calculated for Andes berry, coffee cut stems, and cocoyam‐based biorefineries were 9.27, 35.6 and 683 ton day−1, respectively. These results showed the application of the design strategy and how it allows the determination of the minimum amount of feedstock to be processed to achieve a positive economic performance, and from this point, to calculate the rate of return that an investor would require and the appropriate scale to achieve it. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Highlights • Lactic acid is produced from xylose and glucose using a genetically modified strain. • The modified strain presents yields very close to the theoretical. • The process was simulated to develop a technical and economic analysis. • The scale of production has great influence on the distribution of costs. • The industrial implementation of the strain is possible due to its versatility. Abstract In this work, d -lactic acid production was evaluated from a simulated hydrolysate of corn stover (32 g/L xylose, 42 g/L glucose) with the metabolically engineered Escherichia coli strain JU15. Based on the experimental results, a technical and economic analysis of the entire process was performed using the Aspen Plus software. As a result, it was possible to show that the strain can efficiently produce lactic acid from both sugars, reaching a final concentration of 40 g/L and a yield of 0.6 g lactic acid/g sugars. The process is economically viable at higher scales of 1000 tons/day. The cost distribution is influenced by the scale of the process; on a larger scale, the cost of raw materials represents a higher percentage of total cost than it does on smaller scales. The use of a metabolically engineered strain allows a better use of the sugars obtained from agroindustrial residues. [ABSTRACT FROM AUTHOR]

Highlights • Production of animal feed, a biofuel, a biochemical and food for human consumption. • Assessment of a biorefinery exploiting compositional diversity of an unused feedstock. • Determination of the Minimum Processing Scale for Economic Feasibility. • Feasible biorefinery without risking food security and competing with land use. Abstract During the last decades, the use of biomass has increased considerably for the production of chemicals, biofuels, and direct bioenergy, among others. However, the use of first and second-generation biomass has been raising concerns about the possibilities of threatening food security and to compete for the use of productive land. Biomass is a versatile feedstock based on different compounds with the potential to obtain a considerable spectrum of products. However, it is still necessary to look for cheap raw materials that might have high availability and with the potential for obtaining added-value products without risking food security and decreasing the environmental impact. Cocoyam (Xanthosoma sagittifolium) is a plant grown extensively in tropical regions and mainly used as a source of starch and animal feed. It consists of three parts: leaves, which have a high protein and fiber content; stem, composed of lignocellulose; and a corm, with a starch content similar to that of cassava and potatoes. Nigeria, China and Ghana produce around 1.3, 1.18 and 0.9 million tonnes/year, respectively. In Colombia, they are not technified crops, but it is used mainly as animal feed. Cocoyam use is generally limited to the leaves, discarding the other parts. Based on the potential use of these discarded parts, this work proposed a biorefinery using cocoyam as feedstock to obtain different products: a feed (animal consumption), a biofuel (ethanol), a bioproduct used as food preservative (lactic acid) and food for direct human consumption (starch). The assessment of the potential of the biorefinery included an experimental stage to obtain the products, a simulation stage of techno-economic and environmental assessment and an analysis of the scale to determine minimum processing scale of feedstock at which the biorefinery is economically feasible. The obtained results showed that exploiting the compositional diversity of an unused raw material, it is possible to efficiently produce chemicals, food, feed and biofuels under a biorefinery scheme. The obtained yields for the feed additive, ethanol, lactic acid and starch were 0.147, 0.062, 0.110 and 0.192 kg/kg of feedstock, respectively. Starch, lactic acid and the feed additive are the products that have a higher contribution to the incomes of the process. The minimum processing scale for economic feasibility of the biorefinery was 880 ton/day, which is in the order of commercial scale production plants. The proposed process integrally uses a raw material and does not threaten food security. [ABSTRACT FROM AUTHOR]

This paper presents the technical–economic and environmental assessment of four lignin extraction processes from two different raw materials (sugarcane bagasse and rice husks). The processes are divided into two categories, the first processes evaluates lignin extraction with prior acid hydrolysis step, while in the second case the extraction processes are evaluated standalone for a total analysis of 16 scenarios. Profitability indicators as the net present value (NPV) and environmental indicators as the potential environmental impact (PEI) are used through a process engineering approach to understand and select the best lignin extraction process. The results show that both economically and environmentally process with sulfites and soda from rice husk presents the best results; however the quality of lignin obtained with sulfites is not suitable for high value-added products. Then, the soda is an interesting option for the extraction of lignin if high quality lignin is required for high value-added products at low costs. [ABSTRACT FROM AUTHOR]

Abstract: In this paper the fuel ethanol production from empty fruit bunches was experimentally evaluated using alkaline pretreatment and enzymatic hydrolysis for sugars release. Fermentation was accomplished using a native Saccharomyces cerevisiae strain. Ethanol concentration was carried on using a glass bench-scale distillation column. Experimental results were used for planning and designing the process scheme using Aspen Plus. Process simulation allowed calculating the mass and energy balances. It was found that coupling alkaline pretreatment with a later autoclaving improved the sugars yield in enzymatic hydrolysis. However, the use of the remaining soaking solution from pretreatment as hydrolysis medium had negative effects on sugars yield suggesting that there exist inhibit substance for the enzyme. Better results for enzymatic hydrolysis were obtained when sodium acetate buffer was used. Ethanol yield obtained from both experiments and simulation were very similar (66.50 and 65.84 dm3 of ethanol per each t of empty fruit bunches, respectively). These low ethanol yields were obtained because the native S. cerevisiae does not assimilate all reducing sugars, suggesting that those sugars were pentoses. Simulated alkaline and autoclaving pretreatment contributed only with 2% of the total energy consumption (198.4 GJ m−3 ethanol) while product recovery represented 57% of the total energy. [Copyright &y& Elsevier]

Highlights • Assessment of co-digestion of milk whey and potato stem was performed for the first time. • Raw material cost was the main economic parameter to define the codigestion viability. • Sensitivity analyses were performed to assess the influence of raw material cost. • Heat and electricity generation through co-digestion was simulated with Aspen Plus. • Digestate valorization increases the viability of heat and electricity generation. Abstract Energy conversion strategies based on lignocellulosic and industrial waste streams is considered a challenge in many countries producing huge quantities of biomass. The production of biogas as an energy vector has been gaining attention in the industry sector due to the energy policies for wastes managements or the feasibility of using the biogas for electricity and steam generation. An interesting feedstock alternative for the biogas production is milk whey, one of the main residues of the dairy industry. Additionally the potato stem generated in the harvest stage can be an attractive raw material for biogas production. Co-digestion is the combination of biodegradable raw materials to improve the balance of nutrients in anaerobic digestion. In this context, the characteristics of milk whey and potato stem are not enough to consider it as a good single substrate. However, the synergetic use of these two residues can represent an improvement in biogas production. The biogas production was calculated in Aspen Plus software using stoichiometric and kinetic models based on the experimental characterization of both materials. Through seven different scenarios: potato stem digestion, milk whey digestion and five co-digestion relations of both materials. Heat and electricity generation using biogas was analyzed. Then the generation of heat and electricity was simulated, where the economic profit was evaluated in terms of the production cost, capital cost, revenues and net present value. In terms of biogas production, the scenarios that involved high organic load were the best. For the economic assessment the raw material cost had the most influence over the total processing cost (80% approximately). However, even if energy is produced it is necessary to include the valorization of the digestate as biofertilizer in order that the different scenarios present economic viability. [ABSTRACT FROM AUTHOR]

Abstract: Coffee cut-stems (CCS) represent a promising candidate for fuel ethanol production in tropical countries because of their high availability and high biomass yield per hectare. In this work, pretreatment of this agricultural residue with dilute sulfuric acid and liquid hot water (LHW) was integrated in the simulation and economic assessment of the process for fuel ethanol production. High reducing sugars concentration and ethanol yields were obtained with the LHW pretreatment at a high energy cost. Acid pretreatment is still one of the most applied technologies for lignocellulosic materials due to its efficiency and lower energy consumption. For the determination of the pollution environmental impact index of the process with and without cogeneration system, the Waste Reduction Algorithm (WAR) was used. Thus, the high lignin and low water contents of the coffee cut-stems signified a high potential for energy cogeneration. [Copyright &y& Elsevier]