Bioenergy and Biofuels

Konur, O. (Ed.), 2018a. Bioenergy and Biofuels. CRC Press, Boca Raton, FL. ISBN:978-1-138-03281-1 (Hardback). 485 pp. DOI: https://doi.org/10.1201/9781351228138 Bioenergy and Biofuels | Ozcan Konur | Taylor & Francis eBooks, Refere (taylorfrancis.com)

This book aims to inform readers about the recent developments in bioenergy and biofuels covering current issues from an interdisciplinary approach. It will also feature coverage of anticipated future trends related to each particular biofuel. Chapters will consist of original research presented by world class experts in their respective fields. A number of interdisciplinary areas will be incorporated such as Energy & Fuels, Biotechnology, Genomics, Economics, Optimization, Chemical Engineering, Mechanical Engineering and Algae Science. Examples will relate to a matrix of biofuel and energy types such as bioethanol, biobutanol, and biomethane.

Preface

Konur, O. (2018) Preface. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. ix-xx, Boca Raton, FL, CRC Press.

Section 1 Bioenergy and biofuels in general

Konur, O. (2018) Bioenergy and biofuels science and technology: Scientometric overview and citation classics. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 3-63, Boca Raton, FL, CRC Press. Bioenergy and biofuels science and technology | 1 | Scientometric over (taylorfrancis.com)

With the ever-increasing human population and the ever-diminishing petroleum-based energy resources, energy security, food security, and environmental issues such as global warming, greenhouse gas emissions, and climate change have become a significant public concern in recent decades and bioenergy and biofuels have emerged as the potential key resources to address these concerns. However, as Hill et al. (2006) note, an optimal set of bioenergy and biofuels should “provide a net energy gain, have environmental benefits, be economically competitive, and be producible in large quantities without risking food security.” This paper presents data on the scientometric overview of the research on bioenergy and biofuels as well as the data on 50 citation classics in this research field and discusses the current emerging issues from an interdisciplinary perspective building on the recent pioneering scientometric studies in this field. The paper provides the base for the structure of the book in the lines of bioenergy and biofuels in general, liquid biofuels, gaseous biofuels, solid biofuels, and bioenergy (microbial fuel cells for bioremediation and bioelectricity production). There were more than 106,000 articles and reviews published in English between 1980 and April 2017, of which 60.4% were published recently in the 2010s, and the annual research output rose over 11,000 papers. The bulk of the citation classics (72%) were in biofuels in general terms and liquid biofuels. The paper concludes that these scientometric studies provide valuable insights for the stakeholders on the current state of the research in bioenergy and biofuels, highlighting the primary players such as authors, institutions, countries, grant bodies, and journals as well as highlighting influential papers significantly impacting the development of the research in their respective research streams. Further research as well as more detailed studies are recommended on the research streams identified in this paper.

Koizumi (2018) Biofuel developments and cooperation among China, Japan, and Malaysia. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 65-86, Boca Raton, FL, CRC Press. Biofuel developments and cooperation among China, Japan, and Malaysia (taylorfrancis.com)

The governments of China and Japan are promoting biofuel programs to deal with energy security and environmental problems and to enhance agricultural and rural development. These countries are producing biofuels from nonfood resources, such as agricultural residuals such as rice and wheat straw and crop cobs. However, the high enzyme cost and collection expense are major obstacles to production expansion. Rice and wheat straw are categorized as second-generation biofuels. It is believed that this category of biofuels does not have a negative impact on agricultural and food markets. However, rice and wheat straw can compete with feed use in Japan. The Chinese government has tried to produce biofuels using nonfood feedstock such as cassava, sweet potato, and other crops. The government categorizes cassava and sweet potato as nonfood feedstock, which can have negative impact on food security in some developing countries because cassava and sweet potato are staple foods in these countries. Japanese research institutes, universities, and private companies have accumulated research and development (R&D) technologies to reduce production cost. The technical transfers from Japan to China and other Asian countries are crucial factors in promoting biofuel production from nonfood resources in China and Asia.

Chye, J.T.K., Jun, L.Y., Yon, L., Pan, S., and Danquah, M.K. (2018) Biofuel production from algal biomass. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 87-117, Boca Raton, FL, CRC Press. Biofuel production from algal biomass | 3 | Bioenergy and Biofuels | J (taylorfrancis.com)

Rapid growth of population coupled with urbanization and industrialization is responsible for a high degree of environmental deterioration due to excessive consumption of fossil fuels. The emission of greenhouse gases, a natural consequence of the combustion of fossil fuels, can further exacerbate the situation because it can stimulate a global climate transformation and also cause adverse effects on human health. Consequently, development of clean, renewable, and sustainable alternative energy sources has garnered widespread attention across research communities. Among the potential renewable energy resources, eco-friendly biofuels hold a high degree of promise. Extracts or derivatives from a plethora of edible and nonedible crops, for instance soybeans, vegetable oils, animal fats, and agricultural and forest wastes, have been exploited for biofuel production. In spite of this, concerns such as competition with food crops and the usage of cultivable land for the production of first- and second-generation biofuel feedstocks persist. This necessitates and signifies the applicability of the third-generation biofuels, specifically derived from microalgae, which have been touted to be viable and promising feedstocks for biofuel production. The fact that microalgae have higher growth rates due to their high photosynthetic efficiencies ensures high yields of lipid oil and high biodiesel productivity, and thus pose a distinct advantage over other feedstocks. In the context of environmental issues, microalgae can mitigate the land-usage challenge to a great extent and hence alleviate subsequent deforestation, loss of biodiversity, and environmental pollution. Here, we review the in-place process technologies for biofuels production, including cultivation and harvesting technologies for microalgae biomass production, and conversion technologies from microalgal biomass to biofuels. Furthermore, we focus on the biochemical characteristics of various algal species, as well as the production of biodiesel, bioethanol, and biogas from algae biomass. This chapter collates useful information that may drive development of feasible, economical, and efficient technologies for biofuel production from microalgae with an eye on the coming era. Also, few recommendations are made for additional improvements in biofuel production technologies from microalgae in order to achieve economic feasibility for pilot-scale industrial applications.

Section II: Liquid biofuels

Moser, B.R. (2018) Biodiesel. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 121-143, Boca Raton, FL, CRC Press. Bioenergy and Biofuels | Ozcan Konur | Taylor & Francis eBooks, Refere (taylorfrancis.com)

Biodiesel is defined by ASTM International as a fuel comprised of monoalkyl esters of long-chain fatty acids (FAs) derived from vegetable oils or animal fats, designated B100, and meeting the requirements of ASTM D6751. The European biodiesel standard, EN 14214, de facto defines biodiesel as FA methyl esters (FAMEs). Consequently, alternative fuels such as neat vegetable oils, hydrocarbons prepared therefrom via hydrotreatment, or Fischer–Tropsch diesel produced by gasification of biomass do not technically qualify as biodiesel, despite their occasional reference as such. As the name implies, biodiesel is a substitute or blend component for middle distillate fuels (petrodiesel) for combustion in diesel engines and generators and is thus not suited for spark-ignition (gasoline) engines. The primary reason lipids are converted to biodiesel as opposed to their direct use as fuel is their excessive kinematic viscosity (KV) that is approximately an order of magnitude higher than petrodiesel. For example, KVs (40°C) of soybean oil, soybean oil methyl esters (SMEs) and ultra-low-sulfur (< 15 parts per million S) diesel (ULSD) fuel are 31.49, 4.12, and 2.30 mm²/s, respectively (Moser and Vaughn, 2010). High KV results in poor fuel atomization in the combustion chamber, which causes operational problems such as engine deposits (Knothe, 2005).

Bagchi, S.K., Patnaik, R., and Mallick, N. (2018) Algal biodiesel production – An overview. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 145-171, Boca Raton, FL, CRC Press. Algal biodiesel production | 5 | An overview | Sourav Kumar Bagchi, Re (taylorfrancis.com)

The last decade has witnessed a tremendous impetus on biofuel research due to the irreversible depletion of fossil fuels and the escalating emissions of greenhouse gasses into the atmosphere. Biofuels are subdivided into two major liquid fuels, namely, bioethanol and biodiesel. The lignocellulosic crops like sugarcane and corn are fermented to produce bioethanol, whereas biodiesel, the other transportation fuel, is produced from various lipid-rich sources starting from many food materials ranging from vegetable oils to tiny microorganisms. Bioethanol is generally used in combination with gasoline and biodiesel is blended with diesel to open options for alternative fuel utilization in the transport sector. However, the main concern for the suitability of a biofuel product currently depends on two major factors, that is, the land use and appropriate biomass to fuel energy conversion (Kosinkova et al., 2015). Global biofuel production has been rapidly growing for the last few years, from 15 billion liters in 2000 to 110 billion liters in 2013, and has captured a share of 3.5% of the total transportation fuel in the world (REN21, 2015). We find that biofuels meet nearly one-fourth of the road transport fuel requirements in Brazil. Global biofuel production has been projected to be approximately 140 billion liters by the end of 2018.

Alvarez, J., Amutio, M., Lopez, G., Olazar, M., and Bilbao, J. (2018) Bio-oil production. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 173-202, Boca Raton, FL, CRC Press. Bio-oil production | 6 | Bioenergy and Biofuels | Jon Alvarez, Maider (taylorfrancis.com)

The most significant aspects of the knowledge of the fast biomass pyrolysis are collected in this chapter, with the objective of analyzing bio-oil production (fast pyrolysis) and its valorization for the production of fuels and raw materials. Attention is focused on the aspects of applied interest for the large-scale implementation of fast pyrolysis by analyzing the effect of reaction conditions, features of alternative reactors, and the state of the art of different technologies. The authors have also examined the initiatives for improving pyrolysis in order to condition bio-oil properties for direct use as fuel or for its subsequent valorization, and to reduce the operating limitations and energy requirements (using in situ cracking and deoxygenation catalysts, vacuum operation, microwave heating, or oxidative pyrolysis). In addition, this work updates the integration of pyrolysis with an in-line catalytic conversion stage of oxygenated volatiles, focused on the production of either H₂ (reforming catalyst) or light olefins or BTX aromatics (with HZSM-5 zeolite catalysts). Among the alternatives for bio-oil valorization, emphasis has been placed on the catalytic processes and the bio-oil role as H₂ vector for the production of light olefins or aromatics, as well as raw materials to be introduced in refinery units, such as in fluid catalytic cracking (FCC) units, together with other oil-derived streams.

Cardona Alzate, C.A., Garcia, C. A., and Loaiza, S.S. (2018) Bioethanol production: Advances in technologies and raw materials. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 203-236, Boca Raton, FL, CRC Press. Bioethanol production | 7 | Advances in technologies and raw materials (taylorfrancis.com)

Since the late 20th century, the concept of bio-based molecules has become more important (Clark and Deswarte, 2008). Those molecules derived from biomass through transformation routes such as extraction, thermochemical, chemical, biological, and hybrid can be used as building blocks to obtain added-value chemicals, biofuels, and biomaterials, among others. However, in recent biofuels-driven projects, using biomass as a raw material to obtain bioenergy and replacing the fossil fuels continues to be the leading strategy (Clark and Deswarte, 2008). This chapter reviews the most used feedstocks and technologies to produce bioethanol as the main biofuel to date and takes account of the implementation of new advances in its production through integrated biorefinery concept.

Kumar, M., Bhowmick, T.K., Saini, S., and Gayen, K. (2018) Current status and challenges in biobutanol production. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 237-262, Boca Raton, FL, CRC Press. Current status and challenges in biobutanol production | 8 | Bioenergy (taylorfrancis.com)

The superiority of biobutanol as a fuel for vehicles over other biofuels has been reported numerous times in recent years (Kumar and Gayen, 2011). Therefore, fermentative production of butanol has attracted the attention of various new research groups in academia and industries. In a review, we have already summarized the development and challenges in fermentative production of biobutanol until 2011 (Kumar and Gayen, 2011). In this chapter, we will highlight the further developments in this field along with the outstanding challenges. In spite of several advantages of butanol as fuel for vehicles, there are still some challenges in acetone–butanol–ethanol (ABE) fermentation in terms of low butanol titer, low productivity, and low yield, high cost of pretreatment of cellulosic feedstocks, presence of toxic compounds in feedstock hydrolysates, product inhibition, and costly and low efficiency recovery processes, which make biobutanol less competitive than other biofuels like bioethanol and biodiesel (Zheng et al., 2015). These challenges are being addressed using several strategies. Details of these strategies are discussed in different sections of this chapter.

Section III: Gaseous biofuels

Kumari, S., and Das, D. (2018) Biohydrogen: A zero carbon fuel for the future. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 265-297, Boca Raton, FL, CRC Press. Biohydrogen | 9 | A zero-carbon fuel for the future | Sinu Kumari, Deb (taylorfrancis.com)

In the present energy scenario, energy demand is increasing due to rapid industrialization and urbanization. This energy demand is basically fulfilled by nonrenewable energy sources like petroleum, oil, and natural gases, which have limited reserves. Hydrogen is considered as a fuel for the future. This is mainly for two reasons: (1) it is environmentally friendly (considering water is the only by-product), and (2) it has the highest energy density (142 KJ/g) among all fuels. Hydrogen production by biological process is more promising compared to conventional processes because it can be operated at ambient temperatures and atmospheric pressures by using various types of feedstock. Biohydrogen production includes biophotolysis, photofermentation, dark fermentation, and microbial electrolysis cells. Among these, dark fermentative hydrogen production using both mesophiles and thermophiles are very attractive. These organisms are also capable of using various types of lignocellulosic wastes. This serves a dual purpose: gaseous energy recovery as well as bioremediation.

Pandey, A., and Srivastava, S. (2018) Fermentative hydrogen production: Current prospects and challenges. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 299-311, Boca Raton, FL, CRC Press. Fermentative hydrogen production | 10 | Current prospects and challeng (taylorfrancis.com)

Hydrogen is the most abundant element in the universe and holds great potential for use as an energy source in the future due to its high conversion efficiency recyclability and nonpolluting nature. A number of microorganisms have been identified that are capable of hydrogen production through their metabolic pathways by utilization of specific substrates. For production of hydrogen through the fermentation process, numerous reactors and fermenters have been designed with optimization of the process parameters including type of inoculum used, initial pH in batch-type fermenters, temperature, and metal ion concentration. Other advancements in the optimization of the process include use of mixed consortia, metabolic engineering of the pathways to increase hydrogen production, and use of reverse micelles for entrapment of the cells in them, which in turn offer better distribution of substrates and products in organic and aqueous phase, among other. Still, there is a long way to go to enhance the process efficiency for fermentative hydrogen production.

Tiwari, A., Kiran, T., and Pandey, A. (2018) Algal photobiohydrogen production. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 313-330, Boca Raton, FL, CRC Press. Algal photobiohydrogen production | 11 | Bioenergy and Biofuels | Arch (taylorfrancis.com)

The present situation around the globe calls for efficient renewable alternate energy sources. Hydrogen is crowned as a future fuel owing to a myriad of properties. Hydrogen is renewable, does not pollute the environment by evolving carbon dioxide, liberates large amounts of energy per unit weight in combustion (122 KJ/g), and is easily converted to electricity by fuel cells. Algae-mediated hydrogen production offers a sustainable and environmentally friendly approach to producing clean energy from renewable resources. Algae split water into molecular hydrogen and oxygen using sunlight under special conditions. This chapter highlights the significant progress achieved in algae-mediated hydrogen production. In recent years, significant progress has been achieved in resolving technical bottlenecks for sustained hydrogen production. Inventiveness in algae-mediated hydrogen production is indeed essential for acceptance of hydrogen as an environmentally friendly energy source.

Kadier, A., Jiang, Y., Lai, B., Rai, P.K., Chandrasekhar, K., Mohamed, A., and Kalil, M.S. (2018) Biohydrogen production in microbial electrolysis cells (MECs) from renewable resources. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 331-356, Boca Raton, FL, CRC Press. Biohydrogen production in microbial electrolysis cells from renewable (taylorfrancis.com)

Microbial electrolysis cell (MEC) is a novel bioelectrochemical device that produces hydrogen and value-added products from waste biomass or wastewaters. In recent years, the research interests in MECs have grown tremendously because of their high hydrogen conversion efficiency, low input energy requirement, and applicability to many organic feedstocks. Consequently, the MEC technology has been rapidly advancing. However, MECs are still in the early stages; several technical challenges remain prior to scale-up and their real-world application. Much work is needed on biofilm engineering, reactor architectures, and electrode materials to improve overall performances of system. This chapter presents an introduction to the MEC technology and its operating principle, electron transfer mechanism. Furthermore, the most crucial factors to enhance performance of MEC such as the MEC reactor design and materials are comprehensively reviewed. Finally, the main technical challenges and future research directions are discussed.

Wang, L., Zhang, B., and Joseph, G. (2018) Biogas production and quality control. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 357-385, Boca Raton, FL, CRC Press. Biogas production and quality control | 13 | Bioenergy and Biofuels | (taylorfrancis.com)

Biogas that is primarily methane (CH₄) and carbon dioxide (CO₂) can be produced by anaerobic digestion (AD) of organic matters, such as crop residues, manure, municipal wastes, and food wastes in landfills, or anaerobic digesters. Various technologies have been developed to enhance biogas production, which include feedstock pretreatment, codigestion, AD microbial management, and trace element supplementation. Codigestion of animal manure and agricultural residues could make AD profitable at current energy prices. Biogas can be used to generate heat and electricity. Methane in biogas can be concentrated to the same standards as natural gas. Biogas can be reformed into cleaner fuels like syngas and hydrogen. There are various biogas purification methods available such as water scrubbing, chemical absorption, pressure swing absorption, membrane separation, and biofilters to remove impurities such as hydrogen sulphide (H₂S) and CO₂. This chapter is focused on the review of the biogas production principles and processes, and the latest technologies for the enhancement of biogas production and upgrading.

Section IV: Solid biofuels

Nanda, S., Dalai, A. K., Pant, K.K., Gokalp, I., and Kozinski, J. A. (2018) An appraisal on biochar functionality and utility in agronomy. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 389-409, Boca Raton, FL, CRC Press. An appraisal on biochar functionality and utility in agronomy | 14 | B (taylorfrancis.com)

Today, the exploitation of fossil fuels worldwide has led to rising greenhouse gas emissions, especially CO₂, air pollution, and global warming. These environmental issues have recently increased global attention for alternative energy supply, especially from renewable resources. Any form of renewable carbon in waste plant biomass and animal manure, as well as organic matter in industrial effluents, municipal solid wastes, sewage sludge, and other waste materials can be transformed to hydrocarbon-based biofuels. Biofuels, especially those produced from agricultural crop residues, forestry biomass, algae, energy crops, and new plants for photosynthesis, use oil-seed plants and are considered carbon-neutral because of the CO₂ emitted from their combustion. In other words, the energy content in biofuels is derived from biological carbon fixation. This chapter aims to throw light on pyrolysis and gasification as the technologies to produce biochar from a broad range of feedstocks. A special emphasis of this chapter is on the agronomic applications of biochar, especially in carbon sequestration, soil amelioration, crop improvement, and heavy metal adsorption.

Section V: Bioenergy

Ortiz-Martinez, V.M., Salar-Garcia, M.J., Hernandez-Fernandez, F.J., de los Rios, A.P., Tomas-Alonso, F., and Quesada-Medina, J. (2018) New materials and configurations for microbial fuel cells. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 413-434, Boca Raton, FL, CRC Press. New materials and configurations for microbial fuel cells | 15 | Bioen (taylorfrancis.com)

Microbial fuel cells (MFCs) can be considered as one of the most promising technologies to help address the challenge of climate change (Hernández-Fernández et al., 2015). These devices can convert the chemical energy present in a substrate, such as wastewater, into electricity, offering a twofold benefit, electricity generation and water treatment. Bacteria in the anode chamber degrade the substrate (oxidation) and transfer the electrons released to the anode through an external circuit. Protons pass through the proton exchange membrane to the cathode, where they react with oxygen (reduction) and the electrons from the anode to form water. MFCs can be set up in double-chamber or single-chamber configurations. Double-chamber designs include both an anodic and a cathodic chamber, commonly separated by a selective separator for ion exchange, while single-chamber MFCs only comprise an anodic chamber, with the cathode electrode exposed to the air (Du et al., 2007; Oliveira et al., 2013). The main components (anode, cathode, and separator) and the final design in which they are assembled play a key role in MFC performance and efficiency. In recent years, studies focused on MFCs have grown exponentially because this technology still shows certain limitations associated with their practical implementation. The high cost of some materials, such as proton exchange membranes or precious catalysts, and the complexity of MFC configurations have limited their commercial use. This chapter describes the most significant advances made in terms of materials and designs for MFC construction. The information covered ranges from the simplest and lowest cost materials to those more complex options that can even outperform noble metals. Furthermore, the chapter also includes the evolution of the MFC assemblies developed in recent years, including the discussion of operational parameters.

Borole, A.P. (2018) Bioelectrochemical biorefining. In: Konur, O. (Ed.) Bioenergy and Biofuels, pp. 435-462, Boca Raton, FL, CRC Press. Bioelectrochemical biorefining* | 16 | Bioenergy and Biofuels | Abhije (taylorfrancis.com)

Bioelectrochemical biorefining is a new concept that has evolved from the field of microbial fuel cells and electrolysis cells. It targets integration of microbial electrochemical cells into the biorefinery (Figure 16.1). The idea is to use low-value resources to generate electrons and then use the electrons to produce value-added products. This can enable production of fuels and chemicals from waste and biomass using electrons as intermediates. Thus the name bioelectrochemical biorefining. Electrons are the simplest and most common energy carriers of many energy transfer systems and energetic molecules. Thus, using them as the vehicle for conversion of existing renewable resources into products needed for the 21st century is the primary goal of this marriage between microbial electrochemical technology and biorefineries.

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