Volume 1: Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment.

Konur, O., ed. 2021. Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment. Boca Raton, FL: CRC Press. https://doi.org/10.1201/9780367456238

This first volume of the Handbook of Biodiesel and Petrodiesel Fuels presents a representative sample of the population papers in the field of biodiesel fuels in general.

Part I provides an overview of the research field on both biodiesel and petrodiesel fuels highlighting primary and secondary research fronts in these fields.

Part II presents a representative sample of the population papers in the field of biooils covering major research fronts. The research on the biooils is a fundamental part of the research on the biodiesel fuels. The research in this field has intensified in recent years with the application of advanced catalytic technologies and nanotechnologies in both production and upgrading of biooils. It covers pyrolysis, hydrothermal liquefaction, and upgrading, and characterization and properties of biooils besides an overview of the research field.

Part III presents a representative sample of the population papers in the field of biodiesel fuels in general covering major research fronts. The research in this field has progressed in the lines of production, properties, and emissions of biodiesel fuels. As in the case of biooils, catalysts and additives play a crucial role for the biodiesel fuels. It covers biomass-based catalyst-assisted biodiesel production, enzymatic biodiesel production, additives in biodiesel production, properties, characterization, performance, and policies of biodiesel fuels besides an overview of the research field.

Part IV presents a representative sample of the population papers in the field of glycerol, biodiesel waste, covering major research fronts. The research in this field has intensified in recent years with the increasing volume of biodiesel fuels, creating eco-friendly solutions for these wastes of biodiesel fuels for producing valuable biofuels and biochemicals from glycerol. It covers biohydrogen and propanediol production from glycerol as a case study for bioenergy and biochemicals, respectively.

This book will be useful to academics and professionals in the fields of Energy Fuels, Chemical Engineering, Physical Chemistry, Biotechnology and Applied Microbiology, Environmental Sciences, and Thermodynamics.

Ozcan Konur is both a materials scientist and social scientist by training. He has published around 200 journal papers, book chapters, and conference papers. He has focused on the bioenergy and biofuels in recent years. In 2018, he edited Bioenergy and Biofuels, which brought together the work of over 30 experts in their respective field. He also edited the Handbook of Algal Science, Technology, and Medicine with a strong section on the algal biofuels in 2020.

Part I Introduction to the biodiesel and petrodiesel fuels in general

Chapter 1. Konur, O. 2021. Biodiesel and petrodiesel fuels: Science, technology, health, and environment. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Biodiesel and Petrodiesel Fuels | 2 | Science, Technology, Health, and (taylorfrancis.com)

Crude oils have been primary sources of energy and fuels, such as petrodiesel. However, significant public concerns about the sustainability, price fluctuations, and adverse environmental impact of crude oils have emerged since the 1970s. Thus, biooils and biooil-based biodiesel fuels have emerged as an alternative to crude oils and crude-oil-based petrodiesel fuels, respectively, in recent decades. Nowadays, although petrodiesel fuels are still used extensively, biodiesel fuels are being used increasingly in the transportation and power sectors. Therefore, there has been great public interest in the development of environment and human-friendly and sustainable petrodiesel and biodiesel fuels. However, it is necessary to reduce the total cost of biodiesel production by reducing the feedstock cost through the improvement of biomass and lipid productivity. It is also necessary to mitigate the adverse impact of petrodiesel fuels on the environment and human health. Although there have been over 1,500 reviews and book chapters in this field, there has been no review of the research as a representative sample of whole-population studies done in the field of both petrodiesel and biodiesel fuels. This handbook provides such a sample. This chapter introduces the key issues and findings from this representative sample of the research on both petrodiesel and biodiesel fuels, before discussing these key findings.

Chapter 2. Konur, O. 2021. Biodiesel and petrodiesel fuels: A scientometric review of the research. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. A Scientometric Review of the Research | 3 | Biodiesel and Petrodiesel (taylorfrancis.com)

Crude oils have been primary sources of energy and fuels such as petrodiesel fuels. However, significant public concerns about the sustainability, price fluctuations, and adverse environmental impact of crude oils have emerged since the 1970s. Thus, biooils and biooil-based biodiesel fuels have emerged as an alternative to crude oils and crude oil-based petrodiesel fuels, respectively, in recent decades. Nowadays, although petrodiesel fuels are used extensively, biodiesel fuels are being used increasingly in the transportation and power sectors. However, for the efficient progression of the research in this field, it is necessary to develop efficient incentive structures for the primary stakeholders and to inform these stakeholders about the research. This chapter presents a study of the scientometric evaluation of the research on both biodiesel and petrodiesel fuels using two datasets. The first dataset includes the 100-most-cited papers (n = 100 sample papers) whilst the second includes population papers (n = over 121,000 population papers) published between 1980 and 2019. The data on the indices, document types, authors, institutions, funding bodies, source titles, ‘Web of Science’ subject categories, keywords, research fronts, and citation impacts are presented and discussed.

Chapter 3. Konur, O. 2021. Biodiesel and petrodiesel fuels: A review of the research. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press.  A Review of the Research | 4 | Biodiesel and Petrodiesel Fuels | Ozcan (taylorfrancis.com)

Crude oils have been primary sources of energy and fuels, such as petrodiesel. However, significant public concerns about the sustainability, price fluctuations, and adverse environmental impact of crude oils have emerged since the 1970s. Thus, biooils and biooil-based biodiesel fuels have emerged as an alternative to crude oils and crude-oil-based petrodiesel fuels, respectively, in recent decades. Nowadays, although petrodiesel fuels are used extensively, biodiesel fuels are being used increasingly in the transportation and power sectors. However, for the efficient progression of the research in this field, it is necessary to develop efficient incentive structures for the primary stakeholders and to inform these stakeholders about the research. Although there have been over 5,500 reviews, book chapters, and books in this field, there has been no review of the 50-most-cited articles. Thus, this chapter reviews these articles on both biodiesel and petrodiesel fuels. Then, it discusses the findings of the review.

Chapter 4. Konur, O. 2021. Nanotechnology applications in the diesel fuels and the related research fields: A review of the research. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Nanotechnology Applications in Diesel Fuels and Related Research Field (taylorfrancis.com)

Crude oils have been primary sources of energy and fuels, such as petrodiesel. However, significant public concerns about the sustainability, price fluctuations, and adverse environmental impact of crude oils have emerged since the 1970s. Thus, biooils and biooil-based biodiesel fuels have emerged as an alternative to crude oils and crude-oil-based petrodiesel fuels, respectively, in recent decades. Nowadays, although biodiesel fuels are being used increasingly, petrodiesel fuels are still used extensively in the transportation and power sectors. In the meantime, nanotechnology has emerged as an interdisciplinary research field in recent years with applications from bioenergy to biomedicine. Thus, it is crucial to provide an overview of the nanotechnology applications in diesel fuels and related research fields. Although there have been a number of reviews and book chapters in this field, there has been no review of the 25-most-cited articles. Thus, this chapter reviews these articles on nanotechnology applications in diesel fuels and related research fields, highlighting the key findings from these prolific studies. Then, it discusses the findings of these studies.

Part 2 Biooils

Chapter 5. Konur, O. 2021. Biooils: A scientometric review of the research. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Biooils | 7 | A Scientometric Review of the Research | Ozcan Konur | T (taylorfrancis.com)

Crude oil-based fuels, such as diesel fuels, have been primary sources of energy and fuels. However, significant public concerns about the sustainability, price fluctuations, and adverse environmental impact of biooils have emerged since the 1970s. Thus, biooils have emerged as an alternative to crude oils in recent decades. However, for the efficient progression of the research in this field, it is necessary to develop efficient incentive structures for the primary stakeholders and to inform these stakeholders about the research. Scientometric analysis offers ways to evaluate the research in a respective field. This method has been used to evaluate the research in a number of fields. However, there has been no scientometric study of this field. This chapter presents a study of the scientometric evaluation of the research in this field using two datasets. The first dataset includes the 100-most-cited papers (n = 100 sample papers) whilst the second set includes population papers (n = over 20,000 population papers) published between 1980 and 2019. The data on the indices, document types, authors, institutions, funding bodies, source titles, ‘Web of Science’ subject categories, key words, research fronts, and citation impact are presented and discussed.

Chapter 6. Konur, O. 2021. Characterization and properties of biooils: A review of the research. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Characterization and Properties of Biooils | 8 | A Review of the Resea (taylorfrancis.com)

Crude oils have been primary sources of energy and fuels, such as petrodiesel. However, significant public concerns about the sustainability, price fluctuations, and adverse environmental impact of crude oils have emerged since the 1970s. Thus, biooils and biooil-based biodiesel fuels have emerged as an alternative to crude oils and crude oil-based petrodiesel fuels in recent decades. Nowadays, although petrodiesel fuels are still used extensively, biodiesel fuels are being used increasingly in the transportation and power sectors. Therefore, there has been great public interest in the development of biooils, especially their properties and characterization. However, for the efficient progression of the research in this field, it is necessary to develop efficient incentive structures for the primary stakeholders and to inform these stakeholders about the research. Although there have been a number of reviews and book chapters in this field there has been no review of the 25-most-cited articles. Thus, this chapter reviews these articles by highlighting the key findings of these studies on the characterization and properties of biooils obtained from a variety of feedstocks. Then, it discusses these key findings.

Chapter 7. Konur, O. 2021. Biomass pyrolysis and pyrolysis oils: A review of the research. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Biomass Pyrolysis and Pyrolysis Oils | 9 | A Review of the Research | (taylorfrancis.com)

Crude oils have been primary sources of energy and fuels, such as petrodiesel fuel. However, significant public concerns about the sustainability, price fluctuations, and adverse environmental impact of crude oils have emerged since the 1970s. Thus, biooils and biooil-based biodiesel fuels have emerged as an alternative to crude oils and crude oil-based petrodiesel fuels in recent decades. Nowadays, although petrodiesel fuels are still used extensively, biodiesel fuels are being used increasingly in the transportation and power sectors. Therefore, there has been great public interest in the development of biooils, especially pyrolysis oils and their upgrading. However, for the efficient progression of the research in this field, it is necessary to develop efficient incentive structures for the primary stakeholders and to inform these stakeholders about the research. Although there have been a number of reviews and book chapters in this field, there has been no review of the 25-most-cited articles. Thus, this chapter reviews these articles by highlighting the key findings of these studies on biomass pyrolysis and pyrolysis oils. Then, it discusses these key findings.

Chapter 8. Zhang, J., J. Sun, and Y. Wang. 2021a. An overview of catalytic bio-oil upgrading. Part Ⅰ: Processing aqueous-phase compounds. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. An Overview of Catalytic Bio-oil Upgrading, Part 1: | 10 | Processing (taylorfrancis.com)

The dwindling of fossil resources has motivated the exploration of alternative sustainable energies. One prospective method is the conversion of biomass into bio-oil. The generated crude bio-oil, however, has low heating value, poor volatility, high viscosity, and corrosiveness. It is imperative to further upgrade the crude bio-oil which can be typically divided into two phases: the oil phase that is hydrophobic and the aqueous phase that contains light organic fraction. In this chapter, the challenges and objectives in upgrading bio-oil as a whole are first presented. Then, the authors summarize the developed approaches for the catalytic conversions of the small oxygenates in the aqueous phase of bio-oil to produce valuable fuels/chemicals. The promising catalysts and proposed reaction mechanism are carefully discussed in an attempt to generate a relationship between catalyst properties (e.g. acid-base pairs) with the catalytic performance which may guide the future rational design of catalysts in bio-oil upgrading.

Chapter 9. Zhang, J., J. Sun, and Y. Wang. 2021b. An overview of catalytic bio-oil upgrading. Part Ⅱ: Processing oil-phase compounds and real bio-oil. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. An Overview of Catalytic Bio-oil Upgrading, Part 2: | 11 | Processing (taylorfrancis.com)

In continuation of the authors’ previous discussions on upgrading the aqueous-phase compounds in bio-oil, the state of the art for upgrading compounds in the oil phase and real bio-oil are presented in this chapter. Specifically, they focus on hydrotreating/cracking the phenolics, furanics, or heavier oligomers, as well as the approaches discussed in the last chapter (e.g. steam reforming), to produce valuable fuels/chemicals. In addition, the advances of catalyst development and a reaction mechanism are also discussed, in an attempt to correlate the catalyst structure with performances (e.g. oxophilicity vs hydrodeoxygenation), serving as a basis of design of selective and durable catalysts for bio-oil upgrading.

Chapter 10. Cao, L. C., D. C. W. Tsang, and S. C. Zhang. 2021. Bio-oil production through hydrothermal liquefaction (HTL) of biomass: Recent development and future prospects. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Bio-oil Production through Hydrothermal Liquefaction (HTL) of Biomass (taylorfrancis.com)

Since the Industrial Revolution of the 18th century, fossil fuels have become the means of accessing energy for human society, which currently account for nearly 85% of the total energy consumed worldwide (Jahangiri et al., 2018). The high level of development and utilization of fossil fuels has promoted technological progress and social development. However, traditional fossil fuels damage the environment and cause a large amount of greenhouse gas emissions in the process of their production and use. In addition, the reserves of these fuels, such as coal, oil, and natural gas, are very limited and cannot be used sustainably by everyone (Posmanik et al., 2018). Faced with the increasing exhaustion of fossil energy and the deterioration of the ecological environment caused by its combustion, the development of renewable and sustainable new energy sources has become an urgent need for human survival and development.

Part 3. Biodiesel fuels in general

Chapter 11. Konur, O. 2021. Biodiesel fuels: A scientometric review of the research. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Biodiesel Fuels | 14 | A Scientometric Review of the Research | Ozcan (taylorfrancis.com)

Crude oils have been primary sources of energy and fuels, such as petrodiesel fuel. However, significant public concerns about the sustainability, price fluctuations, and adverse environmental impact of crude oils have emerged since the 1970s. Thus, biooils and biooil-based biodiesel fuels have emerged as an alternative to crude oils and crude oil-based petrodiesel fuels in recent decades. However, for the efficient progression of the research in this field, it is necessary to develop efficient incentive structures for the primary stakeholders and to inform these stakeholders about the research. However, there has been no current scientometric study of the research on biodiesel fuels in general. This chapter presents a study on the scientometric evaluation of the research on biodiesel fuels in general using two datasets. The first dataset includes the 100-most-cited papers (n = 100 sample papers) whilst the second set includes population papers (n = over 6,500 population papers) published between 1980 and 2019. The data on the indices, document types, authors, institutions, funding bodies, source titles, ‘Web of Science’ subject categories, keywords, research fronts, and citation impact are presented and discussed.

Chapter 12. Goh, C. M. H., Y. H. Tan, J. Kansedo, N. M. Mubarak, and M. Lokman. 2021. Biomass-based catalyst-assisted biodiesel production. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Biomass-based Catalyst-Assisted Biodiesel Production | 15 | Biodiesel (taylorfrancis.com)

Biodiesel is well known in developed countries as an alternative fuel, mainly for the transport and agriculture sectors. The physiochemical properties of biodiesel are similar to petroleum diesel but it is a cleaner-burning alternative. Biodiesel has the potential to substitute fossil fuels as an alternative source of energy because of its environmentally friendly and replenishable characteristics. Despite the many benefits biodiesel has to offer, it is uneconomical to manufacture on an industrial scale because of the high cost of feedstock required. Consequently, catalysts should be introduced in order to increase the overall rate of biodiesel production and reduce capital costs. This chapter therefore illustrates the latest breakthroughs involved in the use of biomass-derived catalysts. In addition, an amalgam of experimental data obtained from similar literature has been thoroughly reviewed in order to provide a better framework and methods to synthesize biomass-based catalysts for biodiesel production. This is to provide a solution to the catalyst separation problem in the current biodiesel field and to enhance the economic viability of the industry, thus, sustaining the environment while meeting energy demands.

Chapter 13. Aguieiras, E. C. G., E. P. Cipolatti, M. C. C. Pinto, J. G. Duarte, E. A. Manoel, and D M. G. G. Freire. 2021. Enzymatic biodiesel production: Challenges and future perspectives. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Enzymatic Biodiesel Production | 16 | Challenges and Future Perspectiv (taylorfrancis.com)

The search for more ideal, robust, stable, and low-cost biocatalysts is one of the main challenges related to enzymatic biodiesel production. This chapter focuses on the main technological aspects regarding the use of biocatalysts to convert oils and fats into ethyl esters and methyl esters and the development of alternatives aiming at the implementation of such technologies on an industrial scale. Some important aspects regarding enzymatic biodiesel synthesis are also discussed, highlighting the recent advances in the development of new biocatalysts, including immobilized biocatalysts (by physical adsorption, covalent binding, and entrapment), whole-cell biocatalysts, and lipases obtained by solid-state fermentation, especially in the form of dry fermented solids. In addition, due to the huge impact of refined raw materials costs in the final product prices, studies involving the use of alternative feedstocks are also presented in this chapter. Finally, some case studies are discussed regarding the scale-up efforts and reactor designs for biodiesel synthesis, as well as some economic aspects of enzymatic biodiesel production.

Chapter 14. Tomar, M., H. Dewal, L. Kumar, N. Kumar, and N. Bharadvaja. 2021. Biodiesel additives: Status and perspectives. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Biodiesel Additives | 17 | Status and Perspectives | Mukul Tomar, Hans (taylorfrancis.com)

The biodiesel obtained from vegetable oils and animal fats are considered as the most promising alternative fuel. However, challenges such as poor stability, wax formation, deposits and clogging of engine parts, lower calorific value, and higher NO_x emissions limit its usage to only that of a fuel extender. The amalgamation of fuel additives is a most indispensable approach which can mitigate the drawbacks associated with biodiesel. Additives are the chemicals added to the base fuel in order to bring favorable changes in the properties of the fuel. Depending on their size, state, compound, and features, the additives are broadly classified into different categories such as micro/nanoscale additives, antioxidants, oxygenated, hybrid-based, and biobased. The aim of this chapter is to discuss in depth several types of additives and their role in adding value to biodiesel and its blends. It also highlights the recent advancements in the domain of fuel additives. It also provides an insight into the need for additives to modify fuel properties to our uses. Moreover, the engine characteristics of several fuel blends containing diesel, biodiesel, and their blends are discussed in detail in this chapter.

Chapter 15. Kumar, N. and M. A. Kalam. 2021. Qualitative characterization of biodiesel fuels: Basics and beyond. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Qualitative Characterization of Biodiesel Fuels | 18 | Basics and Beyo (taylorfrancis.com)

Intense research in recent years has shown the viability of biodiesel fuels as a technical and commercial alternative to petrodiesel fuels due to their inherent characteristics, such as renewability, biodegradability, enhanced lubricating ability, high cetane number, and availability in domestic regions, as well as having an environmentally friendly emission profile. The acceptability of biodiesel may look straightforward from the perspective of its properties, but that perception is somewhat deceptive since its suitability is hindered by some shortcomings, including oxidative instability, inferior cold flow properties, unsaturation, higher cost, lower volatility, water absorbency, and lower energy content. The performance of an engine in many ways depends upon the properties of the fuel. The properties of biodiesel are a function of many factors, including the feedstock quality, the fatty acid composition of the feedstock, the process of conversion, as well as the catalyst and alcohol used, the post-production parameters, and the storage condition and duration. This implies that a probable variation in the properties of biodiesel is always possible and which may be anticipated by a number of variables. Accordingly, many studies are available in the public domain, which have dealt with these issues and the probable causes and respective solutions. This chapter is an attempt to analyze and summarize these issues with the help of relevant data and technical information. This work will also pave the way toward the commercialization of biodiesel fuels.

Chapter 16. Hoang, A. T., V. V. Pham, and X. P. Nguyen. 2021. Use of biodiesel fuels in the diesel engines. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Use of Biodiesel Fuels in Diesel Engines | 19 | Biodiesel Fuels | Anh (taylorfrancis.com)

It is a fact that the emissions originated in vehicles have remarkable influence on human health, the living environment, and the ecological systems. Therefore, stricter regulations have been set to govern the emission standards of vehicles. In recent years, significant research progress has been made relating to alkyl esters of vegetable oils or animal fats, normally referred to as biodiesel, aiming to assess the suitability of biodiesel regarding the performance and emission characteristics of diesel engines. Biodiesel has been accepted as a promising alternative fuel with renewable, nontoxic, and eco-friendly properties, as well as having sustainable applicability to diesel engines. Biodiesel could partly replace fossil-originated fuels so as to lower toxic pollutants and, more importantly, to curb the life-cycle emissions of carbon monoxide. This chapter focuses on evaluating biodiesel feasibility as used in diesel engines. Further, aspects relating to engine durability and performance, deposit formation, the corrosiveness of biodiesel on engine components, as well as the emission characteristics of diesel engines running on biodiesel-based fuels – like nitrogen oxide, particulate matter, hydrocarbon, and carbon monoxide emissions – are thoroughly analyzed and compared to those of petrodiesel fuel for both ‘common rail direct injection’ and conventional diesel engines.

Chapter 17. Jain, S. K., S. Kumar, and A. Chaube. 2021. Biodiesel promotion policies: A global perspective. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Biodiesel Promotion Policies | 20 | A Global Perspective | Shashi Kuma (taylorfrancis.com)

Considering the global perspective of biodiesel, there is a need for a localized coordination of biofuel development and a food reserve system to protect poor people. Taking advantage of the opportunity that biodiesel offers for widespread rural development, developing countries must address the policy, regulations, and public investment constraints that generally affect their agricultural development. Biofuels need to be integrated within a broader framework of investment in the rural infrastructure regarding human capital. Large-scale plantation-type schemes should be promoted as part of a pro-poor development strategy to generate employment and income, and to make biodiesel affordable to the poor. Smaller feedstock producers for biodiesel can be assisted by legislation that sets quotas, requiring the large oil processors to source minimum quantities from small scale farmers. The expectation that any biodiesel feedstock can substitute significantly for oil imports will remain unrealistic unless there is an improvement in the genetic potential of oil yields and production practices. Any potential biodiesel feedstock must ensure reclamation of degraded farmland along with local processing and utilization of oil in a way that can improve and diversify rural livelihood, particularly for the disadvantaged rural poor in semi-arid regions. In addition, improvement in water retention and soil conditions must also be an important priority. The actual role, played by biofuels in the apparently increased connection between oil prices and food prices, is of significant policy relevance. Developed countries have promoted biodiesel policies as being environmentally dependent so as to mitigate the impact of global warming and air pollution.

Part 4. Glycerol

Chapter 18. Konur, O. 2021. Glycerol: A scientometric review of the research. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur. Boca Raton, FL: CRC Press. Glycerol | 22 | A Scientometric Review of the Research | Ozcan Konur | (taylorfrancis.com)

Crude oils have been primary sources of energy and fuels, such as petrodiesel. However, significant public concerns about the sustainability, price fluctuations, and adverse environmental impact of crude oils have emerged since the 1970s. Thus, biooils and biooil-based biodiesel fuels have emerged as alternatives to crude oils and crude oil-based petrodiesel fuels, respectively, in recent decades. Furthermore, glycerol, a by-product of biodiesel fuels, has been used to produce further biofuels and biochemicals, thus reducing the production cost of biodiesel fuels. However, for the efficient progression of the research in this field, it is necessary to develop efficient incentive structures for the primary stakeholders and to inform these stakeholders about the research. This chapter presents a study of the scientometric evaluation of the research in this field using two datasets. The first dataset includes the 100-most-cited papers (n = 100 sample papers) whilst the second dataset includes population papers (n = over 6,900 papers) published between 1980 and 2019. The data on the indices, document types, authors, institutions, funding bodies, source titles, ‘Web of Science’ subject categories, key words, research fronts, and citation impact are presented and discussed.

Chapter 19. Ayodele, B. V., S. I. Mustapa, and M. A. Alsaffa. 2021. Hydrogen-rich syngas production from biodiesel-derived glycerol: An overview of modeling and optimization strategies. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur Boca Raton, FL: CRC Press. Hydrogen-Rich Syngas Production from Biodiesel-derived Glycerol | 23 | (taylorfrancis.com)

Glycerol is a major by-product of biodiesel production. It has the potential to be used as a feedstock for the production of hydrogen-rich syngas through various thermo-catalytic processes such as pyrolysis, steam reforming, supercritical water gasification, and supercritical water reforming. In this chapter, the authors present an overview of the various strategies that have been employed for modeling and optimization of hydrogen-rich syngas production from thermo-catalytic conversion of biodiesel-derived glycerol. The various challenges and opportunities associated with each of the modeling and optimization strategies will be identified with a view of charting a new research direction.

Chapter 20. Konur, O. 2021. Propanediol production from glycerol: A review of the research. In Handbook of Biodiesel and Petrodiesel Fuels: Science, Technology, Health, and Environment. Volume 1. Biodiesel Fuels: Science, Technology, Health, and Environment, ed. O. Konur Boca Raton, FL: CRC Press. Propanediol Production from Glycerol | 24 | A Review of the Research | (taylorfrancis.com)

Crude oils have been primary sources of energy and fuels, such as petrodiesel fuels. However, significant public concerns about the sustainability, price fluctuations, and adverse environmental impact of crude oils have emerged since the 1970s. Thus, biooils and biooil-based biodiesel fuels have emerged as alternatives to crude oils and crude oil-based petrodiesel fuels in recent decades. Nowadays, although petrodiesel fuels are still used extensively, biodiesel fuels are being used increasingly in the transportation and power sectors. There have also been great public concerns about the by-product of biodiesel fuels, glycerol, in recent years as waste materials were produced in large volumes. In the light of these concerns, glycerol has been converted into biofuels, such as biohydrogen and biochemicals, for example propanediols. Although there have been a number of reviews and book chapters on the propanediol production from glycerol, there has been no review of the 25-most-cited articles in this field. Thus, this chapter reviews these most-cited articles by highlighting their key findings on propanediol production from glycerol as a case study of biochemical production from glycerol. Then, it discusses these key findings.