Search

Ample interest for more efficient utilization of bio-based residues has emerged in the Nordic pulp and paper (P&P) industry, which uses virgin wood as feedstock. Although different bioenergy retrofit technologies for production of liquid, solid, and gaseous bioenergy products have been applied in the existing P&P mills, the number of installations remains small. The lack of profound knowledge of existing bioenergy retrofits hinders the replication and market uptake of potential technologies. This review synthesises the existing knowledge of European installations and identifies the key drivers and barriers for implementation to foster the market uptake of potential technologies. The bioenergy retrofits were reviewed in terms of technical maturity, drivers, barriers and market potential. Based on this evaluation, common drivers and barriers towards wider market uptake were outlined from political, economic, social, technical, environmental, and legal perspective. Technologies already commercially applied include anaerobic fermentation of sludge, bark gasification, tall oil diesel and bioethanol production, whereas lignin extraction, biomethanol production, hydrothermal liquefaction and hydrothermal carbonization are being demonstrated or first applications are under construction. The findings of this review show that a stable flow of residues at P&P mills creates a solid base for retrofitting. New innovative bio-based products would allow widening the companies' product portfolios and creating new businesses. Also, European Union's (EU) legislation drives towards advanced biofuels production. Wider uptake of the retrofitting technologies requires overcoming the barriers related to uncertainty of economic feasibility and unestablished markets for new products rather than technical immaturity.

Ample interest for more efficient utilization of bio-based residues has emerged in the Nordic pulp and paper (P&P) industry, which uses virgin wood as feedstock. Although different bioenergy retrofit technologies for production of liquid, solid, and gaseous bioenergy products have been applied in the existing P&P mills, the number of installations remains small. The lack of profound knowledge of existing bioenergy retrofits hinders the replication and market uptake of potential technologies. This review synthesises the existing knowledge of European installations and identifies the key drivers and barriers for implementation to foster the market uptake of potential technologies. The bioenergy retrofits were reviewed in terms of technical maturity, drivers, barriers and market potential. Based on this evaluation, common drivers and barriers towards wider market uptake were outlined from political, economic, social, technical, environmental, and legal perspective. Technologies already commercially applied include anaerobic fermentation of sludge, bark gasification, tall oil diesel and bioethanol production, whereas lignin extraction, biomethanol production, hydrothermal liquefaction and hydrothermal carbonization are being demonstrated or first applications are under construction. The findings of this review show that a stable flow of residues at P&P mills creates a solid base for retrofitting. New innovative bio-based products would allow widening the companies' product portfolios and creating new businesses. Also, European Union's (EU) legislation drives towards advanced biofuels production. Wider uptake of the retrofitting technologies requires overcoming the barriers related to uncertainty of economic feasibility and unestablished markets for new products rather than technical immaturity. Publishers version

Large material usage and high production cost restrict the widespread use of solar cells in our society as a clean energy source. A feasible way toward inexpensive solar cells is root in our ability to fabricate solar cells on cheap substrates as the substrate represents 25%–60% of total material costs in current solar cells. Recent efforts to develop solar cells on low cost, flexible, renewable, biodegradable, and versatile paper have rendered encouraging and intriguing results. Paper can not only be taken as a promising substrate to support various solar cells, but also can act as functional elements such as light management layer to improve the power conversion efficiency (PCE) of solar cells. The following sections summarize up-to-date progress on the solar cells fabricated on both common and emerging paper substrates and identify the major challenges for paper solar cells that need to be overcome before they can move from the laboratory to industry. Among these reports, a highest 6.7% PCE to date for solar cells on common paper is reported. Paper solar cells demonstrated their potential application in low-cost and disposable paper electronics as a power source. Possible applications include gadgets, product tracking, smart parcels, security identification, and copy protect.

Renewable energy production throughout low-voltage grids has gradually increased in electrical distribution systems, therefore introducing small energy producers - prosumers. This paradigm challenges the traditional unidirectional energy distribution flow to include disperse power production from renewables. To understand how energy usage can be optimized in the dynamic electrical grid, it is important to understand the behavior of prosumers and their impact on the grid’s operational procedures. The main focus of this study is to investigate how grid operators can obtain an automatic data-driven system for the low-voltage electrical grid management, by analyzing the available grid topology and time-series consumption data from a real-life test area. The aim is to argue for how different consumer profiles, clustering and prediction methods contribute to the grid-related operations. Ultimately, this work is intended for future research directions that can contribute to improving the trade-off between systematic and scalable data models and software computational challenges. This work is financially supported by the Danish project RemoteGRID, which is a ForskEL program under Energinet.dk with grant agreement no. 2016-1-12399.

There is a significant opportunity now for investors to build, own, and operate biorefineries at existing pulp and paper sites that will work synergistically and economically for the pulp and paper mill owner and the biorefinery owner. The pulp and paper industry is the world’s largest nonfood biomass collection system. The pulp and paper industry is a mature industry producing low-margin commodity products. But it has the ideal infrastructure, experience, and resources to capitalize on the strategic interest in renewable fuels via the biorefinery. Industry leaders, investors, policy-makers, and others are now beginning to better understand the vital role to be played by biorefineries as we move from a fossil fuel-based energy economy toward a bio-based one. When properly located and operated, the potential of an integrated forest biorefinery is expected to be huge: a very attractive and synergistic business opportunity for both the colocated pulp and paper mill and the biorefinery itself. Biorefineries are a key pathway to our biofuture, displacing fossil fuels and supplying clean, renewable, and carbon neutral energy. Biorefineries fit very well at pulp and paper mills because of their inherent ability to gather and process biomass and create energy from biomass.

Post-consumer paper, or waste paper, is an important, renewable raw material source for the paper industry and can contribute considerably towards reduction in its imports. Its recycling is also important from the environmental perspective, as systematic collection and recycling of waste paper can significantly reduce the generation of municipal solid wastes. Legal provisions on waste, regulating recovery and recycling of paper have become an essential framework for the paper industry. Legislation in various countries has attempted to promote material recycling and to decrease the waste generation that requires disposal in suitable facilities. In most developed nations, waste paper recycling is organised and operated by the municipal authorities, supported by suitable national policy normally based on the ‘polluter pays’ principle. Legislations are formulated in the form of directives, procurement policy guidelines as well as voluntary agreements. The collection mechanisms put in place are highly successful, as indicated by continuous improvement in the recovery rates of waste paper. These countries not only meet their domestic requirements but also export large quantities of waste paper. A few examples of such legislation are described in this chapter.

This chapter highlights how the growth of distributed power generation in the EU influences the corporate strategies of major European power utilities. Driven to a large extent by renewable support policies, the proportion of distributed power generation has increased in the EU. This has happened to the detriment of the share of electricity supplied by power utilities, which are not only selling less electricity but also facing lower prices for electricity sold, as a result of the changing market conditions. The uptake of distributed renewables adds to the already troublesome outlook for traditional utilities, further eroding their profitability. In response, these firms engage in strategic restructuring, cost-cutting, and the expansion of activities in growth markets outside the EU. The chapter examines the impact of a rapidly growing share of distributed power in the EU and the incumbents' initial response to this new dynamic in their European home markets.

Gasification of biomass is an industrial process utilized to produce product gas that can be used in electrical power generation with internal combustion engines. However, there remain huge challenges with regards to tar and other pollutants, thus their removal before further use is necessary. Non-thermal plasma method can be considered as a novel and efficient way for treatment of tar from product gas. In this work, a laboratory-scale, reverse vortex flow gliding arc plasma reactor was developed and tested for the removal of tar model compound using naphthalene as surrogate. Effects of total gas feed rate in the range of 20–60 L/min, applied voltage in the range of 50–220 V, hence, power input in the range of 300–460 W with initial naphthalene concentration of 610 ± 50 mg/m3 on removal and energy input were investigated. It was found the tar removal efficiency increased with increasing applied voltage. Maximum naphthalene removal efficiency of 85% was achieved at applied high voltage of 15 kV and specific energy input of 0.13 kWh/m3 with energy utilization efficiency of about 4.60 g/kWh. From the findings, non-thermal plasma technology appeared to offer great potential in the removal of biomass tar from gasification. The technology may be promising for possible application to real biomass tar cracking and upgrading of product gas from gasification.

The conventional application of a pulp and paper mill, in which black liquor is typically concentrated and burnt, is compared with the upgrading gasification route for methanol (MeOH) and dimethyl ether (DME) co-production. This comparison is made in terms of exergy efficiency and environmental impact indicators, under different utilities supply scenarios. The combined energy integration and exergy analysis is used to identify the potential improvements related to the decarbonization and mitigation of the process irreversibility. The exergy efficiencies of the conventional scenario and the integrated plants average 40% and 45%, respectively, while the overall emission balances vary from 1.97 to -0.07 tCO2/tPulp, respectively. These results reinforce the relevance of the electricity import from the Brazilian mix for pushing upwards the share of renewable energy resources in the production of traditionally fossil-based chemicals and fuels, which could be an important decision variable in favor to the exploration of forest-based integrated biorefineries.

Lignin has long been considered as an abundant and renewable feedstock to produce biofuels and value-added products. However, its commercialization has been reduced mainly to heat and power generation after its recovery from two of the most used delignification technologies in paper industry, the Kraft and sulfite processes. This chapter reviews the fundamentals and advances in lignin extraction methods, its processing to produce valuable fuels, carbon fiber, plastics, copolymers, and platform chemicals. Since the better understanding of the structure and interactions of lignin in biomass allows efficient downstream processing, the description of its structural compounds and its characterization methods, including nuclear magnetic resonance spectroscopy, are also reviewed. Topics such as the biorefinery lignin valorization, techno-economic analysis, and life cycle assessment are reviewed to evidence the hotspots. This chapter ends with the final opinions on the advances and work-to-do on lignin valorization to improve its manufacturing and competition against petroleum-derived applications.

Microbial fuel cells (MFCs) are a green technology that can directly convert electrical energy from chemical energy contained in organic wastewater. Rice is the most popularly consumed food in Asia. Rice washing before cooking produces an enormous amount of domestic sewage. Rice washing wastewater (RWW) contains various organic matters, minerals, and vitamins. Therefore, in this study, we utilized RWW as biofuel to operate a floating MFC (FMFC). The FMFC was designed with the air-cathode floating on the biofuel and the anode immersed in the biofuel. This design enables the device to float on wastewater sources and to harvest electricity directly from that source. Baker’s yeast and bacteria existing in a natural pond (natural bacteria) were used as biocatalysts. Experimental results showed that the FMFC could generate electricity from RWW using both the baker’s yeast and natural bacteria. The maximum power density ow the FMFC using the baker’s yeast was 1 mW/m2.

The objective of the research was to produce biogas by anaerobic co-digestion of biomass and urban solid waste, which made it possible to take advantage of these organic wastes, transforming them into a renewable energy source such as biogas being a fuel with an high calorific on an average of 19.6 to 25 MJ/m3. The methodology consisted of developing different experiments to evaluate the biogas performance in each of the selected biomasses. The percentage of CH4 and CO2 was determined by gas chromatography, from which the following results were obtained: by rinds of, potato (35.64% CH4), papaya (1.64% CH4), pineapple (0.11% CH4), pea (16.13% CH4), banana (0.39% CH4), bean (0.76% CH4), sugarcane bagasse (80.85% CH4), wet sugarcane bagasse (96.06% CH4), semi-dry sugarcane bagasse (91.39% CH4) and potato peel with sugarcane bagasse (58.74% CH4). After the methane quantification in the different codigestion, the sugarcane bagasse presented better results with a 15% increase in the generation of methane when it was pretreated. Subsequently, we worked with anaerobic biodigesters on a laboratory scale with 500 mL capacity, with a 75% feed (sediment, sugarcane bagasse and water 0.75: 1.5: 1.5). In experimentation 8 with 55% of methane and experimentation 9 with 32%, likewise the energy potential where 15.05 MJ/m3 in experimentation 8 and 16, 72 MJ/m3 in experimentation 9.

The rising amount of organic wastes (biomasses) generated annually constitute serious environmental concerns but hold enormous potentials in solving the increasing global energy demand. When properly harnessed, they are good renewable energy sources with capabilities of bridging the energy demand gaps and ameliorating environmental concerns of developing climes. In this study, the mixed-method approach of anaerobic digestion and thermogravimetry were used in the ranking of eighteen selected agro-industrial biomasses based on their energy (biomethane or thermochemical) conversion potentials. The ultimate and proximate properties of the substrates were determined, then the experimental biomethane potentials (BMP) were carried out via anaerobic digestion of feedstocks at mesophilic conditions for 30 days. The biomasses were also degraded thermally within a temperature range of 50 and 800 °C, torrefaction and the pyrolysis char yields were determined. The calorific values and the theoretical biomethane potentials (TBMP) were calculated from the elemental compositions of substrates. From the results obtained, lignocellulosic plant materials and the animal manures recorded lower methane yields and biodegradability. Although the animal manures had appreciable high heating values (HHVs), their BMP yields were poor with biodegradability as low as 25.8%. Consistent with agro-based biomasses, most of the biomass had low H/C eff , high H/C and O/C atomic ratios. Based on ranking criteria, waste samples from animal carcasses and oil crops were ranked topmost in both thermochemical and biochemical energy conversion. Co-digestion/degradation of high ranked biomass with others and enhancements of the substrate before energy conversion is recommended. Thermal upgrade of biomasses and co-pyrolysis with coal is also recommended.

Rapid industrialization has significantly increased the world’s energy usage. It has been visualized that petroleum-reserves will be scanty, and levels of pollution and global warming will be ample. One can solve these problems by using cleaner and renewable energy sources. Biodiesel can be easily prepared by renewable feed stocks. It is biodegradable and non-toxic as well as it can be used in pure state or by blending with diesel in a diesel engine without any major engine modifications. In this study, biodiesel is produced from tallow oil and blended in different ratios (10%, 20% and 30% abbreviated as B10, B20 and B30 respectively) with diesel and used as an engine fuel to compare combustion and performance characteristics e.g. in-cylinder pressure, rate of pressure rise, mean gas temperature, heat release rate, brake power, specific fuel consumption, brake thermal efficiency and torque. The experimental results showed that engine performance parameters support the use of biodiesel and its blends as fuel as the difference between maximum brake power values of diesel and biodiesel blends(B30) is 1.7% which is un-noticeable, considering its other benefits. The similar results obtained for other characteristics. However, specific fuel consumption was higher in the case of biodiesel blends because of its lower heating value relative to diesel. Considering the fact that animal fat is voluminous by-product of meat Industry and it has limited use otherwise, the present investigation illustrates that biodiesel from animal fat can be used with efficacy without modifications in engine design.

The ever-increasing need of the human beings to energy has brought about concerns regarding the decrease in the amount of energy resources. So, renewable energies have become very important and have obtained a special status in today's world. Using bioethanol as a renewable resource to be blended with other fuels in internal combustion engines has attracted many researchers to itself. Thus, in this study, we assess the amount of bioethanol extracted from cantaloupe waste (Magassi Neishabouri Cultivar) to be used as a fuel. To do so, considering the 15 kg capacity of the device's fermenter, 12 kg of refined cantaloupe sugar syrup and three kilograms of water (with the standard ratio of 4 to 1), i.e. a total of 15 kg of substrate with the brix degree of 20, as well as 75 g of saccharomyces cerevisiae yeast, cultured in standard conditions (5 g of yeast for each kilogram of substrate) were transferred into the fermenter. The tests were conducted in 35 h with three replications and at three different rotation speeds of the fermenter's mixer. Sampling took place every five hours. Fermentation temperature was set as 30 °C and distillation temperature was set to be 78.5 °C which is the standard temperature of bioethanol's boiling point. The results showed that about 49.5 g of bioethanol were extracted from each kilogram of cantaloupe syrup. In comparison to the results obtained by other researchers, it became clear that due to its high sugar level, cantaloupe waste is one of the appropriate options for the production of bioethanol. In addition, considering the rate of the alcohol produced and in order to optimize energy consumption, it was seen that the best speed for the fermenter's mixer, was 120 rpm. Keywords: Bioethanol, Renewable energy, Cantaloupe waste

Fossil fuels account for 80% of the primary need for energy consumption in the world. The imbalance between the demand and supply promoted the researchers to look at the renewable alternative energy source. Among other renewable energy sources, microalgae have considered as primary and important feedstock to replace fossil-based energy due to their high growth rate and biochemical composition. Algae with 30% of lipid content can generate more amount of biodiesel when compared with other best source of renewable energy. The efficiency of lipid extraction from algae and converting into fatty acid methyl esters is a great task in the biodiesel production process. In this chapter, feedstock selection, harvesting, extraction, and purification processes in improving the efficiency of biodiesel production from microalgae are discussed. Technological development and integrated biorefinery concepts make microalgae a potential source for biodiesel production.

Exploration of renewable resources for industrial sustainability has been the foundation of varied research. Biofuel production from renewable resources is one of these research areas that has grown in past few years. Glycerol (GL), a byproduct of the biodiesel industry, was of commercial value years back. A boom in biodiesel production directly magnified the generation of GL, which was then considered a serious waste, demanding cost and energy for its disposal. Recently, GL’s popularity again gained momentum, when it was explored as a cost-effective, renewable raw material for the synthesis of various molecules of industrial significance. Procedures have been established to alter bioglycerol products with commercial value, which will safeguard the sustainability of the biodiesel and oleochemical industries. One likelihood is to convert glycerol to propanediols (PDs), glycerol carbonate (GC), and epichlorohydrin, which have abundant applications like food additives, and as a raw material in the pharmaceutical and cosmetic industries. As an intermediate, GC is directly employed in numerous industrial applications. The universal market of 1,3-propandiol is growing rapidly due to the growing demand for its high-value derived products. Epichlorohydrin can be employed as a homopolymer or copolymer, solvent, and stabilizer for various productions. An industrial forecast has been done for these biobased molecules for the years 2020–27. The US GL market is evaluated at 750.4 kt in the year 2020. It is anticipated that by the year 2027 the probable market size will be 814.2 kt. The biobased chemical market has boomed in the past few years and is expected to increase at a compound annual growth rate of 16.67% in 2019–27. GL and its derivatives (PD, GC, epichlorohydrin) have an inferred role in bioeconomy.

Bioethanol is a biodegradable and high-octane motor fuel derived from cellulosic matter present in plants. Bioethanol production using biomass of second-generation plant lignocellulosic material as a substrate is promising for a pollution-free environment. The most rich, inexpensive, and renewable energy resources for producing bioethanol are the plant biomass of lignocellulosic material. Lignocellulose from second-generation biomass for bioethanol production requires pretreatment using physicochemical, mechanical, chemical, and biological methods. Pretreatment reduces the complex nature of structures into simple monomers and then changes them into bioethanol using ethanol-producing microorganisms. Pretreatment is required mainly to enhance the digestibility of cellulose by increasing enzyme accessibility. The complex nature and ultrastructure of lignocellulosic second-generation biomass involve the linear glucose molecule, which is tightly bounded by the lignin molecule, preventing accessibility of the glucose molecule. Pretreatment removes the lignin molecule and provides access to accessibility of this glucose molecule for ethanol production. To maximize the positive potential of biofuels and minimize their negative impact, proper deployment of a consistent scientific framework is required. Lignocellulosic materials are composed of different types, based on the pretreatment process and conditions that are selected for hydrolysis. This chapter discusses pretreatment methods of lignocellulosic material that optimize ethanol production and the economic perspective of pretreatment.

Lignocellulosic biomass as an abundant source of renewable carbon has received ample interest for the production of fuels and chemicals. Reducing recalcitrance of biomass in a cost-effective way is a challenge to commercialize biomass-based technologies. Deep eutectic solvents (DESs) are emerging as a new “green” solvents that have a high potential for biomass processing. This chapter presents background and general information on the subject.

Biomass-derived fuels are emerging as an excellent alternative to fossil fuels due to several associated benefits such as diversification of biomass and renewable and environmentally friendly nature. However, the various challenges associated with the conversion process limit their production. Biomass yield, its storage, and transportation to the energy generation location are the essential parameters for biofuel commercialization. The physicochemical properties and structural variations of biomass significantly influence the production yield. The evolution of biofuel from different feedstock can be classified into four generations. Pretreatment is one of the crucial steps when dealing with complex biomass to improve their utilization. Pretreatment may cause an enhancement in biomass crystallinity, degradation of sugars, formation of inhibitory compounds, and so on, resulting in poor production yields. Enzymatic hydrolysis is essential when the biomass is directed to a fermentation process in deriving liquid biofuel such as bioethanol, biobutanol, and so on. However, the cost, activity, and enzyme contact time are the crucial aspects that need to be considered. Biomass can be converted to liquid or gaseous fuel through different routes of biochemical and thermochemical processes such as fermentation, anaerobic digestion, pyrolysis, gasification, transesterification, and so on. The challenges not only are limited to the production of biofuel but also include their downstream processing, purification steps, and coproduct formation. Water availability and recycling is also an important factor for biofuel production. The impact of biofuel on the environment and economy of the overall process also influences the commercialization of biofuels. In this chapter, the opportunities and challenges associated with biofuel production and their commercialization are discussed.

Malaysia, a global major producer for palm oil, has tremendously produced more than 100 million tons of oil palm-derived solid biomass (OPSB) annually over the last 5 years summed up from oil palm fronds, empty fruit bunch, trunks, and mesocarp fibers. This OPSB has huge potential to be exploited as green energy sources replacing fossil fuel. However, owing to the recalcitrant and complex microstructure of the biomass, an efficient biomass conversion technology is required to reap the benefits of the OPSB. This chapter discusses the OPSB potential and zero-waste conversion technology developed to produce valued-added material, particularly the bio-succinic acid (BSA). The chapter discusses the efficient OPSB pretreatment and its impacts, the enzymatic hydrolysis, and the fermentative production of BSA, including strategies for enhanced BSA production. Finally, it also addresses the major issues/challenges and the way forward for future commercialization.

Ex-situ biomethanation (CO2 + 4H2 → CH4 + 2H2O) can simultaneously achieve renewable electricity storage and CO2 valorisation. However, fluctuations in variable renewable electricity may lead to intermittent hydrogen supply, which is shown to adversely affect microbial activity and performance of the biomethanation process. Carbonaceous materials may act as an abiotic additive to enhance microbial robustness and improve system performance. Nanomaterial graphene and pyrochar were compared to assess their effects on biomethanation systems with an intermittent supply of hydrogen. Results revealed that intermittent gas supply caused deterioration in the restart performance with only 66% of theoretical methane production obtained in the control compared with 84% under steady state conditions. The addition of graphene in biomethanation led to 78% of the theoretical methane production after repetitive intermittent supply; this improvement is postulated to be due to its high electrical conductivity and large specific surface (500 m2/g). In comparison, pyrochar amendment did not lead to a significant improvement in upgrading performance. Microbial analysis showed that the OTUs affiliated to bacteria withinin the order SHA-98 (42.9% in abundance) and archaea from the genus Methanothermobacter (99%) may result in the establishment of a new syntrophic relationship to improve the robustness of biomethanation process.

An indirect two-stage solar tunnel dryer has been developed to study the drying characteristics of two chili pepper varieties. The effect of chili layer density on the drying time and moisture loss was investigated. Thirteen thin layer-drying models have been analyzed to fit the experimental data. The results showed that the drying process occurred in the falling rate period. A safe storage moisture content of 11–12% (w.b) was achieved within 50–80 h. The moisture diffusivity of both varieties varied from 2.94 E−09 to 4.47E−09 m2 s−1. The Modified Henderson and Pabis and Verma et al. model accurately described the drying characteristics of the MF and BL chili varieties respectively. The efficiencies of the collectors range from 66.44% to 76.53%. The overall system efficiency was found in the range of 24.12–31.3%. The specific energy consumption of the dryer ranged from 2.1 to 2.44 kWh/kg and the CO2 emission was calculated as 53.8 kg/kWh. The energy payback period varied from 2.1 to 2.36 years and the net CO2 mitigation varied from 10.9 to 13 tons per year. The two-stage solar tunnel dryer provide good quality attributes compared to open sun drying. The carbon footprint mitigation of the solar dryer showed that renewable energy-based drying technologies provide better benefit compared to conventional drying systems and the maximum and minimum of the earned carbon credit (ECC) in US dollar was found to be 162.880 and 136.250 per year respectively.

Coppicing is a forest management system in which a dense stand is harvested completely every 3 to 5 years, with shoots for the subsequent cycle growing from the existing root system. The annual yield of wood from this system presently is in the range of 3.5 to 15 tons/A; with a yield of 7 tons/A 1 acre of coppice could provide enough fuel to supply the electricity consumed by 1 person, at present consumption rates. This paper describes management techniques for coppices and discusses the factors affecting yield. A scheme for an integrated system for electricity generation and sewage disposal is described, in which a coppice provides fuel for a power plant serving a nearby city, with the city in turn providing composted sewage as a fertilizer and soil amendment for the coppice. The benefits of coppicing for flood control and strip mine reclamation, and as a renewable energy source for developing countries are also discussed.

In this paper, the implications of the use of hydrogen on product yield and conversion efficiency as well as on economic performance of a hydrogen enhanced Biomass-to-Liquid (BtL) process are analyzed. A process concept for the synthesis of fuel (gasoline and LPG) from biomass-derived synthesis gas via Methanol-to-Gasoline (MtG) route with utilization of carbon dioxide from gasification by feeding additional hydrogen is developed and modeled in Aspen Plus. The modeled process produces 0.36 kg fuel per kg dry straw. Additionally, 99 MW electrical power are recovered from purge and off gases from fuel synthesis in CCGT process, covering the electricity consumption of fuel synthesis and synthesis gas generation. The hydrogen enhanced BtL procces reaches a combined chemical and electrical efficiency of 48.2% and overall carbon efficiency of 69.5%. The total product costs (TPC) sum up to 3.24 €/kg fuel. Raw materials (hydrogen and straw) make up the largest fraction of TPC with a total share of 75%. The hydrogen enhanced BtL process shows increased chemical, energy and carbon efficiencies and thus higher product yields. However, economic analysis shows that the process is unprofitable under current conditions due to high costs for hydrogen provision.

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. Growth in anaerobic digestion (AD) has expanded the use of silage to preserve crops intended for renewable energy generation. Preservation of seasonal crops and their residues is critical in a process that needs continuous feeding. Whilst the impact of different crops and harvesting times on methane formation is relatively well understood, to date the specific considerations for maximising methane yields through management practice have been largely ignored. The present paper reviews the current state of knowledge on silage practice for biogas production and specifically on the factors affecting methane yields of ensiled crops, as well as their influence on the silage quality, and provides suggestions for further research in the field. Data shows that ensiling is able to conserves 93% of crops gross energy when good practices are followed. Shorter chop length (7-10 mm), lower DM feedstock (20-35%) and lower compaction values (less than 250 kg/m3) are used to achieve higher biogas yields. Increase biogas production can also be obtained by managing the organic acids production with the preferential formation of acetic acid and ethanol instead of lactic acid via enzymatic or microbial additives. The review outcomes show that more research is required to provide a clear-cut distinction between the requirements for ensiling crops for AD versus crops for animal feed.

The textile industry uses a huge quantity of water in the processing and manufacturing of textile fabrics. This water ends up in wastewater constituting dye itself as a significant toxic pollutant. Depending on the class of dye, 2.0%–50.0% of the total dye weight used in the process comes in wastewater streams. The nondegradability of dyes enhances its commercial value and attracts its application in textile, food, paper printing, and cosmetics, with the textile industry as the largest consumer, but simultaneously presents environmental risks. The recalcitrant nature of dye prevents its degradation by most of the chemical, physical, or biological processes. The low cost and recalcitrant nature of synthetic dyes make them more acceptable than natural dyes. The largest class of synthetic commercial dyes is “azo dye” which is one among the least degradable ones. Azo dyes are toxic, mutagenic, and carcinogenic in nature, causing severe health hazards and environmental degradation. The untreated or insufficiently treated dye wastewater ultimately reached water bodies imparting color and odor to it. The nondegradable characteristic of dyes severely affects aquatic ecology. The treatment of dye-enriched wastewater, particularly azo dye, from various consumer industries, is a big challenge to the modern world, taking into account its increasing applications. Recently, microbial fuel cell has emerged out as a renewable, biological, and economical wastewater treatment technology that shows its potential in the treatment of azo dye, presenting a solution in the current scenario.

Corn stover (CS) has currently received great attention worldwide as a potential feedstock for the production of bioethanol as alternative renewable fuel or additive to gasoline. This work evaluates the quantities and chemical characteristics of the CS available in Ghana and their conversion into bioethanol. The average quantity of CS production in Ghana per year was estimated to be 1.77 × 106 t. The cellulose, hemicellulose, and lignin contents of CS obtained from Pioneer 30 W 40, a local maize variety, were found to be 37.72 %, 20.62 %, and 30.50 %, respectively. Alkali pretreatment and enzymatic hydrolysis of the CS yielded a reducing sugar concentration of 157.96 mg/ml within 24 h and an ethanol yield of 0.045 l/kg. It was estimated that 40 % of the average annual CS production has the potential of yielding 140.855 × 106 l of bioethanol.

Charred briquettes production is a sustainable way of producing cooking fuel from waste. Unsustainable harvesting of wood for fuel production has contributed immensely to the rapid deforestation in Ghana. This study determined the potential of charred briquettes of sawdust, rice and coconut husks in meeting cooking energy needs of households. In a further step, the acceptability of biomass users in the study to replace their current fuels with charred briquettes was established. The calorific value of the charred briquettes was found to be 24.69 MJ/kg. The highest combustion efficiency of briquettes was determined as 34.7% when a multi-feed gasifier stove (MFGS) was used. There were 14% and 80% reduction in particulate matter and carbon monoxide emissions, respectively when briquettes was used instead of charcoal in the MFGS. The analysis of the production cost of briquettes revealed that 1 kg of briquettes should be sold at Gh¢ 2.48 in order to make a 10% profit. The user acceptability survey indicated that about 40% of respondents are ready to patronize briquettes should it be sold at Gh¢ 2.48. This study established that briquette is a suitable replacement for wood and charcoal, if its full potential is harnessed and the energy utilization efficiency of biomass (sawdust, rice and coconut husts) briquettes is confirmed.

Mono alkyl fatty acid ester or methyl ethyl esters (biodiesel) are the promising alternative for fossil fuel or petroleum derived diesel with similar properties and could reduce the carbon foot print and the greenhouse gas emissions. Biodiesel can be produced from renewable and sustainable feedstocks like plant derived oils, and it is biodegradable and non-toxic to the ecosystem. The process for the biodiesel production is either through traditional chemical catalysts (Acid or Alkali Transesterification) or enzyme mediated transesterification, but as enzymes are natural catalysts with environmentally friendly working conditions, the process with enzymes are proposed to overcome the drawbacks of chemical synthesis. At present 95% of the biodiesel production is contributed by edible oils worldwide whereas recycled oils and animal fats contribute 10% and 6% respectively. Although every process has its own limitations, the enzyme efficiency, resistance to alcohols, and recovery rate are the crucial factors to be addressed. Without any benefit of doubt, production of biodiesel using renewable feedstocks and enzymes as the catalysts could be recommended for the commercial purpose, but further research on improving the efficiency could be an advantage.

The ever-increasing demand for global energy and the disadvantages related to the use of fossil fuels, mainly due to gas emissions during their combustion, are the main driving forces behind the development of renewable energy sources. In this regard, biodiesel is an interesting alternative, and its use could lead to a reduction in greenhouse gas emissions and their release to the atmosphere. In this study, research on heterogeneous catalysis was conducted in order to obtain a CaO catalyst that can be reused in the biodiesel production process. In addition, the transesterification reaction with the use of a heterogeneous catalysis, optimized by full factorial design, was performed. The reaction was conducted in a bench scale re-circulation reactor. The biodiesel obtained was characterized by gas chromatography, to evaluate the ester concentration and physical proprieties, such as density, viscosity and acid concentration. Initially, the best operational conditions were evaluated by data regression using STATISTICA 7.0 ® software. The results were then used to monitor the reaction progress and the catalyst deactivation over time and can verify that the quality of the biodiesel produced is preserved during the experiments. For this, we can conclude that the recycle reactor used in this study give good contribution to innovation in the biodiesel production.

Torrefaction is a promising biomass thermal conversion technology to produce biochar due to its ease of operation and mild operating conditions. In this study, cassava rhizome (CR) was torrified under various sweeping gas types (nitrogen (N2), carbon dioxide (CO2), mixture gas (N2 + CO2)) and flow rates (50, 150, 250 mL/min) at 200 – 300 °C for 30 min. The experimental results show that fuel properties of CR were remarkably upgraded after torrefaction. Sweeping gas has less effect on fuel properties of torrified CR than torrefaction temperature. Torrefaction under CO2 atmosphere produced the biochar with minimum ash content. Torrefaction at 300 °C under 50 mL/min CO2 was recommended as the promising condition to produce biochar replacing lignite coal. Thermal properties and chemical functional groups of the derived biochar suggested that torrefaction process removed mainly oxygen and hydrogen contents which could be achieved through decarbonization (DC), dehydrogenation (DH), and deoxygenation (DO) pathways. Economic feasibility revealed that the torrefaction of CR is cost-advantage under the proposed condition.

Biological wax esters offer a sustainable, renewable and biodegradable alternative to many fossil fuel derived chemicals including plastics and paraffins. Many species of bacteria accumulate waxes with similar structure and properties to highly desirable animal and plant waxes such as Spermaceti and Jojoba oils, the use of which is limited by resource requirements, high cost and ethical concerns. While bacterial fermentations overcome these issues, a commercially viable bacterial wax production process would require high yields and renewable, affordable feedstock to make it economically competitive and environmentally beneficial. This review describes recent progress in wax ester generation in both wild type and genetically engineered bacteria, with a focus on comparing substrates and quantifying obtained waxes. The full breadth of wax accumulating species is discussed, with emphasis on species generating high yields and utilising renewable substrates. Key areas of the field that have, thus far, received limited attention are highlighted, such as waste stream valorisation, mixed microbial cultures and efficient wax extraction, as, until effectively addressed, these will slow progress in creating commercially viable wax production methods.

Nanocellulose is a sustainable and renewable material that has a high surface area and surface tension, excellent mechanical strength and rigidity, high chemical resistance, good stability, high aspect ratio, and, most importantly, an environment-friendly nature. These salient features of nanocellulose have been recognized as a great and untapped prospect in water and wastewater treatment. The nanocellulose and its derivates have been utilized for the removal of heavy metals, dyes, and salts and showed potential as a sustainable replacement for existing water treatment materials. This chapter discusses the recent advancement in the usage of nanocellulose as an adsorbent for water and wastewater treatment. Finally, we highlight the current challenges and limitations related to nanocellulose derived material applications at an industrial scale.

Although the reforming of fossil fuels to syngas followed by catalytic syngas conversion is the common route to produce methanol, concerns over climate change, growing demand for methanol, and depletion of fossil fuels have created interest to produce biomethanol from renewable feedstocks. Typically, the biomethanol production routes could be classified into two main groups based on the applied process. The first group includes the bio-syngas production from biomass resources through gasification, pyrolysis, plasma processing, and anaerobic digestion techniques, followed by bio-syngas conversion to methanol. In the second group, the biomass is biologically converted to biomethane, and the produced biomethane could be converted to methanol through conventional processes. In this chapter, the concept and reaction chemistry of biomass conversion to biomethanol, developed technologies and barriers, and driving forces to commercialize the technologies are presented.

Electrocatalytic (EC) and thermocatalytic (TC) conversion of CO2 to methanol are promising carbon capture and utilization technologies. Herein, these CO2-to-methanol conversion processes are analysed in terms of technical, environmental and economic feasibility. To this purpose, the catalytic performance of the same catalyst (CuO/ZnO/Al2O3) was evaluated in both EC and TC processes. Here is showed for the first time that this catalyst is (apart from TC route) also able to generate methanol through CO2 EC reduction. This work presents lab scale tests, scaled-up simulations and evaluates the environmental and economic performance of these processes. The carbon footprint of the TC and EC processes, scaled-up to the same productivity of ~ 3 kg/h methanol, scored ~ 8 kgCO2 eq/kgCH3OH. Strategies to reduce this impact are presented, such as improving the current density of the EC cell (i.e. 200 mA/cm2 results in a reduction of 68% to 2.72 kgCO2 eq/kgCH3OH) and the availability of 100% renewable electricity (saving up to 62% carbon footprint of both processes). Considering an effective allocation of the methanol productivity on a real market scenario, both the TC and EC processes would start to be economically competitive at methanol productivities > 19.1 kg/h and 3.3 kg/h, respectively. Moreover, if O2 valorisation, a low price of the renewable electricity and a carbon tax are considered, the economic profitability will rise; e.g. the minimum levelised cost of product (LCOP of 1.45 €/kg and 1.67 €/kg, respectively) could be reduced by 53%. Finally, our results pointed out that the CO2 electroreduction process must be optimized (e.g. improving catalysts performance and EC cell design reducing mass transfer limitations) to achieve industrially relevant rates and the maturity of the thermocatalytic technology. Publicado

Plant biomass is a kind of renewable, eco-friendly, abundant, and clean energy. The utilization of plant biomass can reduce reliance on fossil fuels and improve the problem of environmental pollution. Most agriculture, forestry, and food wastes contain ligno-cellulosic resources. The composition of ligno-cellulose can be used to produce biofuels, like bioethanol, biogas, organic acids, and chemicals. This chapter aims to provide a comprehensive overview of the composition, structure, and characterization of plant biomass, including the main components of cellulose, lignin, hemicellulose, pectin, extractives, and inorganic components. They are associated with each other, forming the complex net structures in biomass. While due to the physicochemical, structural, and compositional factors, the useful resources as sugars and other organic compounds cannot be utilized to convert into fuels reasonably and sufficiently. So the impact of plant biomass on pretreatment is discussed in this chapter.

Fossil fuels have several negative effects on the environment, such as greenhouse effects and global warming. Therefore industrialized and developed countries are finding alternative resources in preference to fossil fuels. Fossil fuels such as gasoline and petro-diesel can be replaced by biofuels such as bioethanol and biodiesel. These fuels are renewable and clean and have attracted considerable attention. Different types of nanoparticles have been reported to have an important effect on bioethanol and biodiesel production. In order to produce biodiesel several feedstocks can be used as an oil source in the presence of a catalyst or nanocatalyst. Recently, nanocatalysts have been widely used to produce biodiesel due to their high activity, high specific surface area, and high conversion yield. Bioethanol is a useful fuel, which has shown high renewable and environment-friendly potential. In addition, bioethanol can be produced using fermentation technology for converting carbohydrate into biofuel. In this chapter, different nanomaterials and nanocatalysts are explored for the production of biodiesel from various oil sources. The biodiesel conversion yield for each type of oil is discussed and compared. The effect of nanocatalyst specific surface area on biodiesel production is also outlined. The reusability of nanocatalysts for biodiesel production have also been investigated, showing that nanocatalysts can be used for several cycles of biodiesel production without a significant decrease in efficiency. In addition, the impact of nanomaterials on the immobilization of biocatalysts (enzymes) and bioethanol production is also highlighted.

Biomass is a promising renewable source of energy to supplement the world’s energy requirement. Out of the three basic constituents of lignocellulosic biomass, lignin is the aromatic rich constituent of biomass and is of great industrial attention for its conversion into value added chemicals/petrochemicals. Lignin consisting of three major units namely p-coumaryl, coniferyl, and sinapyl alcohol shows a complex heterogeneous structure with different types of linkages such as β-O-4 aryl glycerol, dibenzodioxane 5-5, α-O-4 and β-O-4’, etc. As the crude industry is slowly moving towards the crude to chemicals and petrochemicals design, it is highly imperative for biomass to support the move by contributing to the production of chemicals/petrochemicals. The aim of this book chapter is to summarize the methods by which lignin can be used for the production of petrochemical based raw materials, etc. The hypothetical mechanism of breaking of various types of linkages of lignin into variety of monomers is also described.

Drop-in biofuels from forest by-products such as black liquor can help deliver deep reductions in transport greenhouse gas emissions by replacing fossil fuels in our vehicle fleet. Black liquor is produced at pulp mills that can increase their pulping capacity by upgrading some of it to drop-in biofuels but this is not well-studied. We evaluate the techno-economic and greenhouse gas performance of five drop-in biofuel pathways based on BL lignin separation with hydrotreatment or black liquor gasification with catalytic synthesis. We also assess how integrated biofuel production impacts different types of pulp mills and a petroleum refinery by using energy and material balances assembled from experimental data supplemented by expert input. Our results indicate that drop-in biofuels from black liquor part-streams can be produced for ~80 EUR2017/MWh, which puts black liquor on the same footing (or better) as comparable forest residue-based alternatives. The best pathways in both production routes have comparable costs and their principal biofuel products (petrol for black liquor gasification and diesel for lignin hydrotreatment) complement each other. All pathways surpass European Union's sustainability criteria for greenhouse gas savings from new plants. Supplementing black liquor with pyrolysis oil or electrolysis hydrogen can improve biofuel production potentials and feedstock diversity, but better economic performance does not accompany these benefits. Fossil hydrogen represents the cheaper option for lignin hydrotreatment by some margin, but greenhouse gas savings from renewable hydrogen are nearly twice as great. Research on lignin upgrading in industrial conditions is recommended for reducing the presently significant performance uncertainties.

Food stores can find themselves in the position of having to dispose of different types of products, such as snacks, confectionery, prepackaged food, drinks and others, Sweet Product Residue (SPR), which presents a great opportunity to produce energy through Anaerobic Digestion (AD), due to its high sugar, carbohidrate and fat contents. In order to valorise SPR, this paper takes into consideration the all necessary treatments; owing the fact that the refuses are constitute by an organic part and packaging (plastic, paper and their combinations), a pretreatment able to remove the latter is necessary. SPR refuse was initially subjected to novel pretreatment approach: extrusion at 200atm to remove the packaging, and a Basic Pre-treatment (BP) then tested through a Two-Stage AD (TSAD) process, for H2 and CH4 productions. The experimental results were analysed considering three parameters: Efficiency (ξ), which takes into account the quantity of the energy produced as hydrogen plus methane that the bioreaction is able to extract; Efficacy (η), which takes into account the efficiency of the actual test, compared with that obtained from a reference test carried out with glucose; Energy Sustainability Index (ESI), which takes into account the total amount of energy produced as H2 plus CH4, and the amount of energy consumed to pre-treat the refuse. The effectiveness of the extrusion process in removing the packaging was very high: about 80% of the organic part present in the SPR was recovered. The obtained results have pointed out that SPR is suitable for energy valorization process: ξ=50%, η=0.67 and ESI=24.4, without the need of basic pre-treatment.

Summary Traditional lignocellulosic feedstock research has focused on biomass characteristics essential for improving saccharification efficiency, yet the key biomass features underlying high-quality renewable lignin materials remain unknown. Nevertheless, modern biorefinery cannot achieve sustainability and cost-effectiveness unless the lignin stream can be valorized. We hereby addressed these scientific gaps by investigating biomass characteristics defining lignin-based carbon materials properties. Lignin from eight sorghum samples with diverse characteristics was fabricated into carbon fibers (CFs). Remarkably, only lignin uniformity was found to define CF mechanical performance, highlighting the new structure-property relationship. Contrarily, lignin content and composition did not impact on carbon material properties. Mechanistic study by XRD and Raman spectroscopy revealed that higher lignin uniformity enhanced CF microstructures, in particular, turbostratic carbon content. The study for the first time highlighted lignin uniformity as an important biomass structure determinant for renewable products, which opened up new avenues for feedstock design toward diverse products enabling sustainable and cost-effective bioeconomy., Graphical Abstract, Highlights • Lignin uniformity was discovered to define biomass-derived CF mechanical property • Traditional key feedstock characteristics do not significantly impact on CF property • Feedstock variants and growth conditions impact on lignin uniformity • Novel feedstock design needs to be developed for biomaterial manufacturing, Polymer Chemistry; Biomass; Materials Chemistry; Materials Property