Assessing the feasibility and sustainability of a surfactin production process: a techno-economic and environmental analysis.

Biosurfactants have been profiled as a sustainable replacement for chemical-based surfactants since these bio-based molecules have higher biodegradability. Few research papers have focused on assessing biosurfactant production to elucidate potential bottlenecks. This research aims to assess the techno-economic and environmental performance of surfactin production in a potential scale of 65m3, considering different product yields and involving the European energy crisis of 2021-2022. The conceptual design, simulation, techno-economic, and environmental assessments were done by applying process engineering concepts and software tools such as Aspen Plus v.9.0 and SimaPro v.8.3.3. The results demonstrated the high economic potential of surfactin production since the higher values in the market offset the low fermentation yields, low recovery efficiency, and high capital investment. The sensitivity analysis of the economic assessment elucidated a minimum surfactin selling price between 29 and 31 USD/kg of surfactin, while a minimum processing scale for economic feasibility between 4 and 5 kg/h is needed to reach an equilibrium point. The environmental performance must be improved since the carbon footprint was 43 kg CO2eq/kg of surfactin. The downstream processing and energy demand are the main bottlenecks since these aspects contribute to 63 and 25% of the total emissions. The fermentation process and downstream process are key factors for future optimization and research.

Prefeasibility analysis of biomass gasification and electrolysis for hydrogen production.

Hydrogen is a key energy vector to accomplishing energy transition and decarbonization goals proposed in the transport and industrial sectors worldwide. In recent years, research has focused on analyzing, designing, and optimizing hydrogen production, searching to improve economic prefeasibility with minimal emissions of polluting gases. Therefore, the techno-economic analysis of hydrogen production by electrolytic and gasification processes becomes relevant since these processes could compete commercially with industrial technologies such as SMR - Steam methane reforming. This work aims to analyze hydrogen production in stand-alone processes and energy-driven biorefineries. The gasification and electrolysis technologies were evaluated experimentally, and the yields obtained were input data for scaling up the processes through simulation tools. Biomass gasification is more cost-effective than electrolytic schemes since the hydrogen production costs were 4.57 USD/kg and 8.30 USD/kg at an annual production rate of 491.6 tons and 38.96 tons, respectively. Instead, the electrolysis process feasibility is strongly influenced by the recycled water rate and the electricity cost. A sensitivity analysis was performed to evaluate the temperature, pressure, and current density variability on the hydrogen production rate. The increase in pressure and current density induces parasitic currents while the temperature increases hydrogen production. Although higher hydrogen production rates from gasification, the syngas composition decreases the possibility of being implemented in applications where purity is critical.

Comparative Analysis of Trifluoracetic Acid Pretreatment for Lignocellulosic Materials.

Lignocellulosic materials are usually processed toward C5 and C6 corresponding sugars. Trifluoroacetic acid (TFA) is a pretreatment method to solubilize hemicellulose to sugars such xylose without degrading cellulose. However, this pretreatment has not been compared to other processes. Thus, this paper focuses on the techno-economic comparison of the C5-C6 production of C5-C6 as raw materials platforms using non-centrifuged sugarcane bagasse (NCSB) and Pinus patula wood chips (PP). Hydrolysates using TFA 2.5 M as an acid were characterized through HPLC regarding arabinose, galactose glucose, xylose, and mannose sugars. Then, simulations of the processes according to the experimental results were done. The economic assessment was performed, and compared with some common pretreatments. The mass and energy balances of the simulations indicate that the process can be compared with other pretreatments. From the economic perspective, the main operating expenditures (OpEx) are related to raw materials and capital depreciation due to the cost of TFA corrosion issues. The processes showed a CapEx and OpEx of 0.99 MUSD and 6.59 M-USD/year for NCSB, and 0.97 MUSD and 4.37 MUSD/year for PP, considering a small-scale base (1 ton/h). TFA pretreatment is innovative and promising from a techno-economic perspective.

Valorization Alternatives of Tropical Forest Fruits Based on the Açai (Euterpe oleracea) Processing in Small Communities.

Many plant species characterize tropical forests, and a small fraction has been studied to favor small communities in the food and medicinal fields. The high biodiversity of these regions allows for the proposed alternatives for the valorization of exotic fruits due to their rich content of value-added compounds that benefit human health. This work focuses on improving the nutritional characteristics of the açai production chain by mixing it with noni and araza. As a main result, it was possible to enhance the organoleptic and nutritional characteristics of the fruits after freeze-drying. Then, the seeds and peels of the fruits were valorized by the extraction of bioactive compounds with conventional methods and biogas production by anaerobic digestion. The best compositions of antioxidant capacity and total phenolic compounds were obtained for the extracts based on the araza peel, with values of 116.4 µmol and 276.6 mg of gallic acid per 100 g of raw material, respectively. Regarding biogas production, the anaerobic digestion performance was influenced by the C/N ratio. The experimental results were used as input to simulate small-scale processes. From a technical point of view, the scheme of açai, noni, and araza mixture (Sc. 4) showed the highest mass yields (0.84 kg products/kg RM) and energy requirement (2.54 kW/kg RM). On the other hand, the processing of single açai (Sc. 1) presented the lowest capital costs (1.37 M-USD) and operating costs (0.89 M-USD/year). However, all scenarios showed techno-economic feasibility and demonstrated the potential of these fruits to valorize the açai market.

Analysis of Single-Step Pretreatments for Lignocellulosic Platform Isolation as the Basis of Biorefinery Design.

Biorefinery feasibility is highly influenced by the early design of the best feedstock transformation pathway to obtain value-added products. Pretreatment has been identified as the critical stage in biorefinery design since proper pretreatment influences subsequent reaction, separation, and purification processes. However, many pretreatment analyses have focused on preserving and valorizing six-carbon sugars for future use in bioconversion processes, leaving aside fractions such as hemicellulose and lignin. To date, there has been no pretreatment systematization for the removal of lignocellulosic fractions. This work defines pretreatment efficacy through operational, economic, environmental, and social indicators. Thus, using the data reported in the literature, as well as the results of the simulation schemes, a multi-criteria weighting of the best-performing schemes for the isolation or removal of cellulose, hemicellulose, and lignin was carried out. As a main result, it was concluded that dilute acid is the most effective for cellulose isolation and hemicellulose removal for producing platform products based on six- and five-carbon sugars, respectively. Additionally, the kraft process is the best methodology for lignin removal and its future use in biorefineries. The results of this work help to elucidate a methodological systematization of the pretreatment efficacy in the design of biorefineries as an early feasibility stage considering sustainability aspects.

Environmental life cycle assessment (E-LCA) and social impact assessment (SIA) of small-scale biorefineries implemented in rural zones: the avocado (Persea Americana var. Americana) case in Colombia.

The objective of this study is to compare the environmental and social performance of two small-scale avocado biorefineries implanted in a rural zone in the North of Colombia. Two small-scale biorefineries were proposed. Small-B1 addressed to produce avocado oil and animal feed, and Small-B2 focused on the guacamole production. The environmental analysis was done by applying the life cycle assessment methodology. Then, agronomic information and process simulation were required to complete the analysis. Moreover, the water footprint of the avocado crops was estimated. Both biorefineries were compared with the direct avocados production and commercialization. The social assessment was achieved by the estimation of quantitative indicators related to wages, jobs, and working hours. The agricultural carbon and water footprints of the creole avocado crop were 0.59 kg CO2-eq/kg and 2.13 m3/kg. In the same way, Small-B1 and Small-B2 obtained a carbon and water footprints of 8.99 kg CO2-eq/kg and 6.63 m3/kg and 0.72 kg CO2-eq/kg and 1.38 m3/kg, respectively. The hotspots of the creole avocado crop are related to the use of fertilizers and fungicides. Then, new strategies should be implemented to reduce the farmer's dependency. The social analysis exhibit a high resilience of the Small-B1 biorefinery since a salary increase to worker about 50% can be proposed. In addition, the installation of this biorefinery can create more than ten jobs. A disjunction was found between the economic, environmental, and social analyses. Thus, the need to establish a multidimensional strategy to design sustainable biorefineries is presented.

Analysis of the routes for biomass processing towards sustainable development in the conceptual design step: Strategy based on the compendium of bioprocesses portfolio.

Process sustainability has been one of the most challenging issues faced by process designers. Conceptual designed processes do not overcome this stage because aspects such as context and technological readiness level are left aside. This paper proposes a strategy to consider different processing routes for biomass (compendium of existing routes) towards sustainable development. The strategy comprises five stages where a supported bioprocesses selection is made by considering the chemical composition of the raw material and the context where biomass is produced and processed. This strategy aims to give decision tools to designers to filter and reduce the number of options to be considered when proposing an alternative biomass use. The proposed strategy was applied to upgrade orange peel waste and sugarcane bagasse to demonstrate how it can be applied. In conclusion, selecting of bioprocesses and considering the proposed strategycould improve the biorefineries design. Even so, more bioprocesses must be included.

Influence of products portfolio and process contextualization on the economic performance of small- and large-scale avocado biorefineries.

This research paper seeks to evaluate the influence of the context, processing scale, and portfolio of products on the economic performance of different avocado-based biorefineries. For this, two scenarios in small and large-scale biorefineries were compared. The case of scenario 1 (avocado oil, animal feed, and electricity production) was the best small-scale alternative to be implemented in rural zones than scenario 2 (guacamole and electricity production). The minimum Processing Scale for Economic Feasibility was 0.85 and 1.1 ton/day for scenarios 1 and 2. Compared to lactic acid and xylitol production, the large-scale process addressed to produce levulinic acid, furfural, and lignin (scenario 1) was the best option (scenario 2). In scenario 1, the minimum Processing Scale for Economic Feasibility was 15.50 ton/day compared with scenario 2 of 41.95 ton/day. Based on these values, scenario 1 has the highest feasibility of being implemented in countries such as Colombia.

Biorefineries as the base for accomplishing the sustainable development goals (SDGs) and the transition to bioeconomy: Technical aspects, challenges and perspectives.

Sustainable development goals (SDGs) are guidelines to improve the socio-economic and environmental worldwide situation caused by excessive fossil fuel use. These goals must be accomplished before 2030 by implementing a national sustainable development framework in all UN country members. Instead, biorefineries are the seed towards a more sustainable world since biomass upgrading into a series of value-added products and energy vectors can reduce current issues related to waste generation and climate change. Besides, biorefineries are the first step on the way to implement a bioeconomy. This review paper aims to elucidate the existing relation between biorefineries, bioeconomy, and the SDGs through a comprehensive analysis of the technical requirements, challenges, and perspectives of biomass upgrading processes. In this way, this review paper includes a discussion about the biorefinery, bioeconomy, sustainable development, and sustainability concepts. Moreover, this paper elucidates how the implementation of biorefineries is linked to the SDGs accomplishment.

Study of biorefineries based on experimental data: production of bioethanol, biogas, syngas, and electricity using coffee-cut stems as raw material.

Energy-driven biorefineries can be designed considering biotechnological and thermochemical conversion pathways. Nevertheless, energy and environmental comparisons are necessary to establish the best way to upgrade lignocellulosic biomass and set the requirements of these processes in different scenarios. This paper aims to evaluate experimentally a biorefinery producing energy vectors using coffee-cut stems (CCS) as feedstock. The obtained yields were the basis for energy and environmental analysis, in two different biorefinery scenarios: (i) production of bioethanol and biogas and (ii) production of syngas and electricity. The energy results indicated that the overall energy efficiency calculated in the first scenario was only 9.15%. Meanwhile, the second biorefinery configuration based on thermochemical routes presented an energy efficiency value of 70.89%. This difference was attributed to the higher consumption of utilities in the biorefinery based on biotechnological routes. The environmental results showed that the impact category of climate change for the first biorefinery (i.e., 0.0193 kg CO2 eq./MJ) had a lower value than that of the second process (i.e., 0.2377 kg CO2 eq./MJ). Thus, the biorefinery based on the biotechnological route presented a better environmental performance. Additionally, the results for both biorefineries allowed concluding that the inclusion of by-products and co-products in the calculation of the environmental analysis can dramatically affect the results.

Supply chain and environmental assessment of the essential oil production using Calendula (Calendula Officinalis) as raw material.

Biomass has been considered a potential source of value-added products and energy vectors. Most biomass studies have researched the best pathways or processes to upgrade this renewable raw material through stand-alone processes or biorefineries. The biomass supply chain is a crucial aspect in the economic analysis of biomass upgrading since most of the raw materials need to be transported. A supply chain analysis gives an idea about the availability, real costs, and storage conditions of the raw material to guarantee an accurate feasibility analysis and a standardized production process. Calendula (Calendula Officinalis) is an aromatic plant used to produce valuable extracts in the cosmetic and pharmaceutical industries. Nevertheless, high amounts of exhausted biomass (more than 95% w/w) are produced and wasted. Theseresidues represent an environmental issue to be solved through the implementation of valorizing options. This paper analyses the supply chain and environmental impact of essential oil production using Calendula (Calendula Officinalis) as a raw material in the Colombian context. The case study comprises a single-objective optimization of the calendula supply chain to produce essential oil and the life cycle assessment (LCA) of the process through a cradle-to-gate approach in the Colombian context. The results showed the best locations to upgrade Calendula in Colombia (i.e., Manizales and Bucaramanga), supplying 1.1 % of the total product demand. The optimal product flow to customers was 0.32 tons/year, and the required feedstock from suppliers was 162 tons/year. The agricultural stage of essential oil production represented the highest environmental impact of the supply chain. In particular, plastic sheets, organic fertilizers, and chemical fungicides were the main contributors to this impact.

Comparison of furfural and biogas production using pentoses as platform.

Coffee cut-stems (CCS), a biomass with high lignocellulosic content, is a coffee crop waste after bean harvesting. The main application of this material is as fuelwood for farmers, disregarding their carbohydrate content for biotechnological processes. In these terms, this work aims to compare three process scenarios for the experimental valorization of C5 fraction from CCS to produce biogas and furfural with and without the ethanol production from remaining C6 fraction under biorefinery concept. Therefore, an experimental stage was performed to obtain these products, based on a previous diluted acid pretreatment. The hydrolysate fraction was used to produce furfural and biogas, achieving yields of 0.34 g of furfural/g xylose and 81.1 mL of CH4 per gram of volatile solids. Concerning the solid fraction after acid pretreatment, it was used to produce ethanol with a previous enzymatic hydrolysis. After fermentation, 0.47 g of ethanol/g of glucose (92% of the theoretical yield) was obtained. These experimental results were fed to simulation models in order to compare three scenarios in technical, economic and environmental terms. As the main results, from technical point of view, the biogas production presents the lowest energy requirements. From the economic perspective, the furfural production presents a prefeasibility at the base scale of processing (e.g., 12.5 ton h-1). Meanwhile, the biogas scenario needs a processing capacity >22.5 ton h-1 to achieve the economic prefeasibility. In the biorefinery case, the positive economic performance is found at processing scales above 83 ton h-1. This work concludes that the C5 sugars platform is identified as a potential alternative for the generation of furfural and biogas, however, in this case a multiproduct biorefinery system is not always the best option to valorize biomass given the very high scale required and the economic indicators.

Analysis of the environmental impact using the waste reduction algorithm in polypropylene production by applying grade transitions strategies in Colombia.

The global manufacturing sector faces a significant challenge about minimizing environmental impacts without witnessing the adverse effects on the market competitiveness. A cleaner production methodology must involve different approaches for minimizing or recycling waste streams, obtaining at the same time economical and environmental advantages for manufacturing companies (Severo et al., J Clean Prod 142:87-97, 2017). In the polypropylene production process, more than 60 grades of polypropylene are produced. To achieve this target, changes in the process variables are carried out, due to the continuous operation process. Those changes generate a mixture of resins with intermediate properties (transition), which must be minimized. Moreover, failures during the transitions process generate a large extra amount of material that represents a significant impact on the environment, when it is considered as waste. In this paper, an environmental analysis was made by applying a waste reduction algorithm (WAR) to establish the potential impact of a polypropylene production process over the environment, applying grade transitions strategies and then to demonstrate how the improvement of transition times implies a significant reduction of plastic waste. It was found that the reduction of transitions time minimizes the environmental impact based on real industry data. Last should be considered for the real polymer plant analyzed and future projects.

Integral use of plants and their residues: the case of cocoyam (Xanthosoma sagittifolium) conversion through biorefineries at small scale.

During last decades, there has been a growing interest of decreasing the environmental impact generated by humans. This situation has been approached from different perspectives being the integral use of raw materials as one of the best alternatives. It was estimated that 3.7 × 109 tonnes of agricultural residues are produced annually worldwide. Then, the integral use of feedstocks has been studied through the biorefinery concept. A biorefinery can be a promissory option for processing feedstocks in rural zones aiming to boost the techno-economic and social growth. However, many plants produced at small scale in rural zones without high industrial use contribute with residues usually not studied as raw materials for other processes. Cocoyam (Xanthosoma sagittifolium) is a plant grown extensively in tropical regions. Nigeria, China, and Ghana are the main producers with 1.3, 1.18, and 0.9 million tonnes/year, respectively. In Colombia, there are no technified crops, but it is used where it is grown mainly as animal feed. This plant consists of leaves, stem, and a tuber but the use is generally limited to the leaves, discarding the other parts. These discarded parts have great potential (lignocellulose and starch). This work proposes different processing schemes using the parts of the plant to obtain value-added products, and their techno-economic and environmental assessment. The simulation was performed with Aspen Plus and the economic package was used for the economic assessment. For the environmental assessment, Waste Algorithm Reduction of the U.S. EPA was implemented. The obtained results showed that the integral use of plants under a biorefinery scheme allows obtaining better techno-economic and environmental performance and that small-scale biorefineries can be a promissory option for boosting rural zones.

Evaluation of biogas and syngas as energy vectors for heat and power generation using lignocellulosic biomass as raw material

The use of nonrenewable energy sources to provide the worldwide energy needs has caused different problems such as global warming, water pollution, and smog production. In this sense, lignocellulosic biomass has been postulated as a renewable energy source able to produce energy carriers that can cover this energy demand. Biogas and syngas are two energy vectors that have been suggested to generate heat and power through their use in cogeneration systems. Therefore, the aim of this review is to develop a comparison between these energy vectors considering their main features based on literature reports. In addition, a techno-economic and energy assessment of the heat and power generation using these vectors as energy sources is performed. If lignocellulosic biomass is used as raw material, biogas is more commonly used for cogeneration purposes than syngas. However, syngas from biomass gasification has a great potential to be employed as a chemical platform in the production of value-added products. Moreover, the investment costs to generate heat and power from lignocellulosic materials using the anaerobic digestion technology are higher than those using the gasification technology. As a conclusion, it was evidenced that upgraded biogas has a higher potential to produce heat and power than syngas. Nevertheless, the implementation of both energy vectors into the energy market is important to cover the increasing worldwide energy demand.

Influencia de las regiones de estabilidad del biorreactor en la producción eficiente de alcohol carburante / Influence of bioreactor stability regions in the efficient production of fuel ethanol

Colombia ha desarrollado un proyecto ambicioso en la producción de alcohol carburante, y actualmente es uno de los países líderes de América Latina en la producción de biocombustibles. No obstante, algunas de sus plantas industriales productoras de etanol presentan problemas durante el arranque y la operación de los fermentadores, que afectan adversamente la productividad del proceso global. Estudios teóricos y experimentales demuestran que el comportamiento dinámico del proceso depende de los fenómenos de estabilidad que exhibe el sistema. En este trabajo se muestra la influencia de las regiones de estabilidad sobre la eficiencia del proceso tomando como criterios de evaluación índices de impacto económico y ambiental. Para esto, se realizó un análisis de estabilidad donde se tomó como parámetro de operación principal la velocidad de dilución. Se empleó un programa propio desarrollado sobre Matlab® para generar diagramas de bifurcación y de fase. El algoritmo de reducción de residuos (WAR) desarrollado por la Agencia de Protección Ambiental de los Estados Unidos, y el software SuperPro Designer®, fueron utilizados respectivamente para hacer la evaluación ambiental y económica del proceso. Como resultado, se evidenció que los procesos continuos de fermentación se pueden llevar a cabo en diferentes regiones de estabilidad, y que las variables de respuesta, tales como el rendimiento, dependen de la región de operación seleccionada. Finalmente, se llegó a la conclusión de que la evaluación de la estabilidad de los procesos de fermentación debe incluirse en las etapas de diseño de bioprocesos para garantizar su buen desempeño.

Colombia has developed an ambitious project to produce fuel ethanol. Nowadays, Colombia is one of the leading countries in Latin America for the biofuels production. However, some of its industrial plants producing ethanol present problems during the startup and the operation of fermenters, which adversely affects the productivity of the global process. Theoretical and experimental studies show that the process’ dynamic behavior depends on the stability phenomenon exhibited by the system. This work shows the influence of the stability regions on the process’ efficiency. For this, economic and environmental index were used. A stability analysis was carried out. The dilution rate was selected as the main operating parameter. An own program developed on Matlab® was used to generate bifurcation diagrams and phase diagrams. The Waste Reduction Algorithm (WAR) developed by the Environmental Protection Agency of the United States, and the SuperPro Designer® software were used for estimating the environmental and economic assessment of the process. As a result, it was shown that continuous fermentation processes can be carried out in different stability regions. Likewise, it was shown that the response variables, such as the yield, depend on the selected operating region. Finally, it was concluded that the evaluation of fermentation processes’ stability must be included in the stages for designing of bioprocess in order to ensure a good performance.

Importance of stability study of continuous systems for ethanol production.

Fuel ethanol industry presents different problems during bioreactors operation. One of them is the unexpected variation in the output ethanol concentration from the bioreactor or a drastic fall in the productivity. In this paper, a compilation of concepts and relevant results of several experimental and theoretical studies about dynamic behavior of fermentation systems for bioethanol production with Saccharomyces cerevisiae and Zymomonas mobilis is done with the purpose of understanding the stability phenomena that could affect the productivity of industries producing fuel ethanol. It is shown that the design of high scale biochemical processes for fuel ethanol production must be done based on stability studies.