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Featured Application: In the last decade, pretreatment has been considered the core stage in the design of biorefineries. Different schemes could be proposed depending on the design objective, either pretreatments for the feedstock fractionation or pretreatments to obtain a platform product. Nevertheless, many have been described as single-step pretreatments specific to a sub-stream, decreasing the integral valorization performance. This work demonstrates the possibility of sequential pretreatment schemes to maximize the fractionation of lignocellulosic biomass. Through different operational, technical, and economic assessment indicators, the best schemes that would help increase the overall process yields and, certainly, the economic viability are described. Therefore, a good pretreatment design will affect the upstream and downstream performance of the biorefineries. Pretreatment technologies are proposed to break the crosslinked biomass matrix and facilitate bioconversion processes or chemical agent attacks in reaction schemes. However, most of the pretreatments are studied in single-step schemes, limiting the integral valorization of the feedstock composition. Therefore, sequential pretreatments could maximize this valorization by isolating more biomass fractions or removing unwanted compounds. This work focuses on proposing and assessing different sequential pretreatments for the isolation of lignocellulosic fractions. After a pretreatment screening, ten technical and economic indicators were assessed through a heuristic analysis. Data from the literature were used to evaluate five operational indicators and as the specification of processing units in simulation schemes to also evaluate five techno-energetic and economic indicators. As a main result, it was concluded that the sequential pretreatments of dilute acid (DA) with wet air oxidation (WAO) could be the most optimal for cellulose isolation, steam explosion (SE) with DA for hemicellulose fractionation, and DA with kraft process for lignin solubilization. Additionally, the DA and WAO sequence may be the most efficient in biorefinery designs since it maximizes biomass fractionation, producing two hydrolyzed liquors, one rich in sugars and the other in soluble lignin, as well as a cellulose-rich solid. [ABSTRACT FROM AUTHOR]

• An integral methodological approach is proposed for the design and assessment of biorefineries. • Conceptual design and optimization are the main stages of proposed strategy. • The mathematical model includes a cogeneration system and a wastewater treatment. • The generic approach is applied to a study case of CCS biorefinery. This paper presents a generic and integral methodological approach for the design and assessment of multiproduct biorefineries. The proposed methodology has been developed based on 2-stage strategy, conceptual design and optimization. In the conceptual design stage, the theoretical data about the biorefinery are collected in order to build the superstructure. In the optimization stage, the formulated superstructure based on surrogate models, is optimized in order to generate the optimal biorefinery configuration where the utilities are produced internally from biomass via a cogeneration system. The proposed framework is applied to evaluate the optimal exploitation of Coffee Cut-Stems (CCS). The results show that ethanol is the most interesting product following dilute acid pretreatment and the fermentation of C5 and C6 sugars due to the large yield of the process. However, an alternative scenario where energy is the protagonist, results in the selection of power and heat as main products. [ABSTRACT FROM AUTHOR]

This is a review of work on the potential of biorefineries. First, it considers the concept of a refinery, the differences between biomass and oil, and the advantages of a biorefinery over a refinery. It goes on to describe the bio‐based economy and biorefinery concepts, and to discuss its origin as a promising alternative to dependence on non‐renewable feedstocks. It provides an exhaustive description of the classification of biorefineries, considering aspects such as systems, technological implementation status, size, feedstocks, platforms, products, and conversion processes. It outlines the main methodologies for designing biorefineries – conceptual design, optimization, and the 'early stage' method. Methodologies for the economic, environmental, and social assessment of a biorefinery are presented. Finally, challenges linked to the implementation of biorefinery projects at industrial level are discussed. The authors conclude that the methodologies of conceptual design and optimization must complement each other to achieve a robust design from a conceptual and mathematical point of view. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The aim of this work was to evaluate the economic feasibility of the bioethanol production (BEP) based on olive tree pruning (OTP) as a biomass feedstock with optimization of the dilute acid pretreatment in focus. For this, the BEP was simulated taking into account the influence of the operating conditions of the pretreatment stage. Then, the techno-economic results were analyzed by means of the response surface methodology (RSM). The results show that lowest price of BE was 1.94 USD l−1 with a yield of 174.12 l t−1 OTP under optimal conditions. As a conclusion, the raw material cost has a strong influence in the economic feasibility of the BEP from OTP. The inclusion of other processing lines into the process would improve the process economy. [ABSTRACT FROM AUTHOR]

• Experimental biorefinery for the production of ethanol, furfural and electricity. • Comparison between simulation and experimentation data for the CCS biorefinery. • Xylose, glucose and syngas used as platforms to generate energy and bioproducts. • Strict connection of experimental procedure and simulation to achieve a real process. Lab and pilot-scale experiments during biorefineries design are mainly needed for modeling and validation purposes. This work presents experiments in a biorefinery based on Coffee Cut-Stems (CCS) to produce ethanol, electricity, and furfural. The biorefinery is proposed based on a flowsheet obtained in previous simulation work. Experimental and simulation results are compared in terms of productivities and conversions. As an overall result, the operating conditions for process stages involved in the CCS biorefinery are adjusted. The yields for the main products were obtained. In ethanol production, a yield of 0.476 ± 0.027 g ethanol per g of glucose is obtained. The dehydration reaction to furfural has a yield of 33.79 ± 0.42%, and the gasifier generates around 4.66kWh of electricity. In conclusion, the yields change significantly in comparison with the simulation results. The experimental work for the CCS biorefinery provided more accurate data for the proposed design. [ABSTRACT FROM AUTHOR]

The use of biomass to obtain value-added products has been a good alternative for reducing their environmental impacts. For this purpose, different studies have been carried out focused on the use of agro-industrial waste. One of the most commonly used raw materials has been bagasse obtained from the processing of sugarcane in high quantities in countries like Brazil, India, China, Thailand, Pakistan, Mexico, Colombia, Indonesia, Philippines, and the United States. From 1 ton of sugarcane, 280 kg of bagasse can be obtained. Sugarcane bagasse (SCB) is a waste that is rich in polysaccharides, which makes it a promising raw material for obtaining products under biorefinery concept. The objective of this work was to analyze from the energetic point of view, different biorefinery schemes in which SCB is employed as a raw material. The design and simulation of the different biorefinery schemes is performed in Aspen Plus software. From this software, it was possible to obtain the different mass and energy balances, which are used in the technical and energetic analysis. Exergy is used as a comparison tool for the energy analysis. These analyses allowed for the selection of the best biorefinery configuration from SCB. [ABSTRACT FROM AUTHOR]

This work presents a techno-economic and environmental assessment for a biorefinery based on sugarcane bagasse (SCB), and coffee cut-stems (CCS). Five scenarios were evaluated at different levels, conversion pathways, feedstock distribution, and technologies to produce ethanol, octane, nonane, furfural, and hydroxymethylfurfural (HMF). These scenarios were compared between each other according to raw material, economic, and environmental characteristics. A single objective function combining the Net Present Value and the Potential Environmental Impact was used through the Analytic Hierarchy Process approach to understand and select the best configurations for SCB and CCS cases. The results showed that the configuration with the best economic and environmental performance for SCB and CCS is the one that considers ethanol, furfural, and octane production (scenario 1). The global economic margin was 62.3% and 61.6% for SCB and CCS respectively. The results have shown the potential of these types of biomass to produce fuels and platform products. [ABSTRACT FROM AUTHOR]

Lignin is widely available in biomass sources, and the aromatic structure can justify its use as a precursor or platform for obtaining value-added compounds. However, lignin is considered a low-price by-product or low-value fuel for energy recovery in the pulping industries. Therefore, the development of technologies and methodologies that promote the valorization and efficient utilization of this biopolymer becomes an essential aspect of biobased processes, especially in biorefineries. This review shows the opportunity to target lignin as a marketable by-product for value-added chemicals through thermochemical, chemical, and biochemical pathways, with or without the absence of catalysts. Likewise, the valorization of lignin includes emerging technologies to produce carbon and polymer materials. This work also emphasizes the description of technical, economic, and environmental aspects that would affect lignin in different biorefinery stages. Therefore, a discussion based on current studies and evaluations of lignin valorization processes is considered. Finally, a preliminary techno-economic and environmental assessment of a wood-based biorefinery was performed as an example to better understand the importance of lignin as a platform product in biorefineries. It includes the processing scale analysis over ten years of the project lifetime. The review established the importance of lignin valorization to increase biorefineries efficiency and sustainability. Image 1 • Lignin depolymerization through thermal and bio-chemical routes have been discussed. • Emerging technologies for lignin-based materials are an alternative in the industry. • Efforts to define the sustainability of lignin-based biorefineries are required. • Lignin oxidation shows an economically feasible route in wood-based biorefineries. [ABSTRACT FROM AUTHOR]

• Waste valorization in the citrus agroindustry is economically viable. • Polyphenols are promising products to strengthen the citrus industry. • The biorefinery concept increases the products portfolio of the citrus agroindustry. • Agroindustrial OPW was analyzed and upgraded in added-value products. • Biocatalysis are a sustainable way to obtain a new series of added-value products. Orange peel waste (OPW) creates challenges regarding environmentally sustainable disposal and potential valorization. Argentina is a major Citrus sp. fruit producer in Latin America. A share of the OPW is used to produce a colloid stabilizer in the beverage industry. However, large amounts of this waste are disposed of in landfills, reducing the orange value chain sustainability. The OPW chemical composition would allow the generation of valuable sub-fractions by applying different upgrading pathways. This review is addressed to summarize the most current and important pathways to upgrade OPW by applying the biorefinery concept. Moreover, this paper highlights the importance of the chemical composition when defining valorization routes. Polyphenols were identified as the most promising and reliable option to increase the sustainability of the orange industry. Then, an overview of extraction conditions, and extracted molecules is included. Biocatalysis is highlighted as a promising way to upgrade polyphenols in other added-value products. A case study is analyzed considering further processing of OPW produced by the citrus agroindustry in Argentina. The case study is related to the design and simulation of a biorefinery addressed to produce juice, essential oil, peel juice, polyphenols, and biogas. The case study is analyzed involving yields and economic performance demonstrating the high potential of essential oil, polyphenols, and biogas as promising products in a near future. As practical implications of this study, an analysis of different pathways to upgrade OPW is given. Moreover, the present study reinforces the chemical characterization as a crucial step before selecting upgrading pathways. [Display omitted] [ABSTRACT FROM AUTHOR]

• Orange peel waste yields 20.14 kg/tonne of mucic acid. • Biogas and mucic acid production costs are reduced by 36 % increasing the OPW flow. • Mucic acid production demands 42 % of the capital investment of the OPW biorefinery. The orange peel waste is essentially an important residue in many countries, representing more a problem than one opportunity. Most of this residue processing is related to low added value products and it includes the generation of other residues. Among new alternatives to valorize this residue during last years a high added value product is the mucic acid. This work addresses the pre-feasibility analysis of the mucic acid production using galacturonic acid from pectin using Orange Peel Waste (OPW) as feedstock through the biorefinery concept. The proposed biorefinery comprises the pectin extraction using citric acid, mucic acid production from the liquid fraction of the pectin hydrolysis, and biogas production using the remaining solid. The experiments for pectin extraction and biogas production were carried out to determine the yields to be used in the process simulation. The material and energy balances of the biorefinery were obtained through the Aspen Plus V9.0 tool. These results were used in the energy, economic, and environmental evaluation. A preliminary environmental evaluation for the process was done with Waste Reduction Algorithm (WAR) software. The experimental pectin hydrolysis and biogas production yields were 0.15 ± 0.77 g/g of OPW, and 0.256 Nm3/kg of OPW, respectively. The technical assessment of the biorefinery shows a good performance. Besides, the economic analysis of the proposed biorefinery exhibited feasibility at a processing scale of 140 kg/h. An economic sensitivity analysis was done varying the raw materials costs. From this, the low influence of the raw materials costs in the economic feasibility of the process was elucidated at different scales. Finally, the environmental analysis exposed that the environmental impact of the exit streams is lower than the impact of feeding streams. [ABSTRACT FROM AUTHOR]