Renewable Diesel: Value Chain, Sustainability, and Challenges

By Bhaskar Singh

Renewable Diesel: Value Chain, Sustainability, and Challenges presents a holistic reference on the production of renewable diesel, from fundamentals to state-of-the-art. In addition to an in-depth assessment of biomass conversation processes and available technologies, the book considers engineering and mathematical aspects such as design, economics and sustainability. Production processes, fuel properties and fuel quality standards are all addressed in detail alongside state-of-the-art information on conversion routes, catalysts, combustion characteristics, emission profile, techno-economic and lifecycle appraisal, and integration of renewable diesel production into existing refineries. A chapter on biodiesel and hydroprocessed vegetable oil offers a comparative analysis with conventional biodiesel pro’s and con’s.

Finally, readers are provided with an overview of techno-economic, environmental, logistical and strategic hurdles and opportunities in the commercialization and marketability of renewable diesel. This book provides readers with a unique and comprehensive reference on the production of renewable diesel that will be of interest to students, researchers and professionals involved in bioenergy, renewable energy, biotechnology, chemistry, chemical engineering, environmental science and sustainability sciences.

• Presents the fundamentals of renewable diesel, its production processes, and fuel properties and standards
• Addresses the differences between Renewable Diesel and Biodiesel through comparative analysis in a dedicated chapter
• Provides real-world designs, real-world economics and real-world sustainability analyses (LCA, LCIA, and LCC)

• Language: English
• Publisher: Elsevier Science
• Release date: Sep 19, 2023
• ISBN: 9780323998062

Book preview

Preface

Dipesh Kumar

The world is currently facing a critical dependence on petroleum, often imported. This dependence has resulted in environmental pollution and climate change, among the prominent drivers for promoting and developing alternative energy/fuels. As a result, there is a massive transition towards alternative and renewable forms of energy. The electricity sector is leading, but other hard-to-abate sectors still await a techno-economically viable and environmentally appealing alternative. The transport sector, for instance, is still facing some challenges despite witnessing a significant surge in the demand and availability of battery-powered powertrains. Limited availability of metals used in batteries, high cost, range anxiety, high weight of batteries, inadequate availability of charging stations, unsuitability for long haul and heavy-duty vehicles and lack of end-of-life management policies are some challenges. Even though the numbers are increasing, e-vehicles still constitute less than 5% of the total vehicular population on the road, and the transition to e-mobility is still not a global phenomenon. Any significant substitution of internal-combustion engine-based vehicles is only expected in the mid to long term. However, the climate cannot wait, and we must continue to work toward finding more environment-friendly alternatives.

An alternative arrangement that is compatible with the existing infrastructure of internal-combustion engines is inherently attractive as changing over to an entirely new fleet of powertrains is daunting and can only be justified in the mid to long run. One option that has been around for some time is alternative fuels derived from oleaginous biomass. Different forms of vegetable oil, such as virgin oil and those derived through blending, pyrolysis, emulsification and transesterification of oleaginous biomass, have all been explored and used. The most commonly produced and used fuel among these is biodiesel, which, although possessing advantages over conventional mineral diesel, also comes with its own set of limitations and challenges. These include its limited miscibility in diesel, poor atomisation and cold-flow properties and inferior stability. The incompatibility of higher biodiesel blends in compression-ignition engines is a significant deterrent for the industry. However, an alternative thermo-chemical treatment of oleaginous biomass, popularly known as hydro-processing or hydro-treatment, is known to overcome these limitations and yields a drop-in fuel called renewable diesel (RD). The chemical composition of RD is similar to that of petroleum diesel, and it can utilise the existing infrastructure of refineries, distribution systems and powertrains. It is clear that RD is an up-and-coming alternative worth considering.

Interestingly, despite RD’s potential and growing appeal, the existing literature on the subject is relatively scanty and scattered. Different terms are often used to refer to the same fuel. Green diesel and hydro-treated/hydro-processed vegetable, second-generation biodiesel oil, etc. are various other terms used to refer to RD, considering the biological origin of the feedstock (free fatty acids and triacylglycerol), which is typical for almost all of the biofuels. Terminology is essential to define the subjects of discussion, much like how it is crucial in chemistry.

This edited volume titled Renewable Diesel: Value Chain, Sustainability, and Challenges by Dipesh Kumar, Bhaskar Singh and Sanjay Kumar Gupta is fascinating and informative. The book aims to compile some critical elements in the value chain and provides a thorough overview of RD. It is fascinating how this volume distinguishes between alternative fuels derived from oleaginous biomass. The volume covers literature on the synthesis of RD (Chapter 1), its quality specifications (Chapter 2), life cycle–based appraisal (Chapter 3), challenges and opportunities (Chapter 4) and the current market status and future industry outlook (Chapter 5). The book also presents a comparative analysis of biodiesel and RD in Chapter 6. Finally, the book also includes a chapter on fuels derived from waste plastics to supplement the research and developmental efforts aimed at developing other alternative fuels (Chapter 7). This volume is an excellent source of well-researched information for scholars keen to learn about alternative fuels.

This edited volume provides a wealth of pragmatic studies and reviews of contemporary developments and opportunities in the field of RD.

Chapter 1

Synthesis of renewable diesel as a substitute for fossil fuels

Krishna Kumar Jaiswal¹, Chandrama Roy Chowdhury², Swapnamoy Dutta³, Ishita Banerjee⁴, Km Smriti Jaiswal⁵, H.M.D. Nisansala⁶,⁷, B. Sangmesh¹ and N.M.S. Sirimuthu⁶,    ¹Department of Green Energy Technology, Pondicherry University, Puducherry, India,    ²Department of Food Science, Czech University of Life Sciences, Prague, Czech Republic,    ³Bredesen Center for Interdisciplinary Research and Graduate Education, the University of Tennessee, Knoxville, TN, United States,    ⁴Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, United States,    ⁵Department of Chemistry, Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, Uttar Pradesh, India,    ⁶Nanocomposite Research Centre, Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda, Western Province, Sri Lanka,    ⁷Faculty of Graduate Studies, University of Sri Jayewardenepura, Nugegoda, Western Province, Sri Lanka

Abstract

The importance of renewable fuel generation has been strongly highlighted in recent years. According to the global scenario, the requirement for renewable and nontoxic fuels is increasing considerably to maintain energy demand and further curb the environmental mutilation caused by fossil fuels. The decrease in the spread of greenhouse gases, government regulations to preserve nature and the unrestricted increase in the prices of petroleum products are the main reasons why renewable fuels are rising in great demand nowadays. This chapter has specifically illustrated renewable diesel, the possible feedstocks and production processes. However, the main focus was to build intensively with biodiesel and renewable diesel. We have also described the most used catalysts in the generation process and discussed their scope to make them low cost and environmentally friendly. In addition to mentioning its production and operation parameters, we have also included the narration of the comparative characteristics between petroleum diesel, biodiesel and renewable diesel to understand and differentiate these three types of fuels. Few companies have already started producing biodiesel and renewable diesel on an industrial scale and investigating to improve its yield and properties; however, manufacturing seems segregated. Therefore the advancement of technologies, research support and large-scale infrastructure for producing and distributing renewable diesel fuel represents its prospects for a green future.

Keywords

Renewable diesel; feedstocks; catalysts, operational parameters; green future

1.1 Introduction

Energy resource is one of the essential needs in the present-day scenario of world today. The extensive use of nonrenewable energy has posed a threat to the global environment as it contributes to global warming and pollution. Also, the inadequate availability of fossil-based fuels is another persistent confront. The limited supply and availability of nonrenewable resources have increased the price of fuel energy, putting financial stress on most people (Shamoon et al., 2022). It also plays an increasing role in hampering and degrading climate conditions around the world. The use of fossil fuels in the automotive industries generates many exhaust gases known as greenhouse gases. The greenhouse gases increase the carbon footprint and contribute to global warming statuses and climate changes. These environmental threats have determined the exploration of alternative energy sources (renewable energy) to reduce the disadvantages of nonrenewable fuels (Heidari & Pearce, 2016). Researchers are now focusing on making renewable fuels and biofuels from biomass and cellulosic materials because the conversion process is more straightforward and affordable.

Biofuels are the ecofriendly alternative fuels or energy resources generated from bio-based material and biomass. It is generally catagorized into the 1st generation, 2nd generation, and 3rd generation biofuels (Jaiswal, Banerjee, & Mayookha, 2021; Jaiswal, Dutta, Banerjee, Pohrmen, & Kumar, 2021; Jaiswal, Kumar, Vlaskin, & Nanda, 2021). 1st generation biofuels include the biofuels which is directly related to the renewable biomass that is more than often edible resources such as biodiesel, bioethanol, etc. 2nd generation biofuels are well-defined as biofuels generated from a wide-ranging feedstocks, mainly but not restricted to non-edible lignocellulosic biomass. The most established explanation for 3rd generation biofuels is a renewable biofuels generated from microalgal biomass, with a prominent growth and yield in comparision to the typical lignocellulosic biomass (Alalwan, Alminshid, & Aljaafari, 2019; Arora et al., 2020; Jaiswal & Prasath, 2016). Recently, the production of bioethanol from the corn and other grains feedstock has been recorded at approximately 15 billion gallons per year. It can also be said that the production of biofuel from crops is equivalent to 10% of current gasoline consumption. Some prominent examples of biofuels can be bioethanol (produced mainly from sugar cane or corn), biogas (generated from vegetable waste, animal manure or other organic materials) and biodiesel (made from animal and vegetable fats/lipids) (Choudhary, Joshi, Rao, & Srivastava, 2021; Jaiswal, Banerjee et al., 2021; Jaiswal, Dutta et al., 2021; Jaiswal, Kumar et al., 2021).

Biodiesel produced from lipids extracted from biomass mainly comprises fatty acid methyl esters (FAMEs). It also contains a small amount of nonester fuel. The use of biomass for generating and developing a renewable energy source is suitable for its neutrality against CO2. Researchers have also focused on producing biofuels from agricultural residues, as they are also good sources of lignocellulose (Limayem & Ricke, 2012). Some of the significant advantages of biomass-based biofuels include the reduced generation of greenhouse gases such as methane, carbon dioxide and nitrous oxide. It also releases fewer pollutants. Therefore it can be said that they contribute less to global warming. They are highly renewable, profitable and efficient. They have a minimal carbon footprint, making them suitable for environmental health and safety. It has been proven that biodiesel can reduce 47% of particles in the atmosphere and 67% of hydrocarbon emissions and reduces smog (smoke+fog). Using agricultural waste in biofuel production can also help to reduce waste problems by 96%. This, in turn, contributes to a 79% reduction in wastewater generation (Ambaye et al., 2021). However, one of the most significant disadvantages of biofuel production is that they are time-consuming and laborious to develop. The cost of production also depends on the complexity of the production process.

1.2 Biodiesel and renewable diesels

Biodiesel is a category of fuel that presents itself as an alternative candidate to the predominant petro-diesel fuels. This type of disel fuels is generally composed of long-chains of methyl or ethyl fatty esters produced from biomass resources that maintain specific standards such as ASTM D6751, EN 14214 (Upare & Upare, 2020). In the early 1930s, it was first observed and soon recognised as a potential substitute for conventionally used transportation fuels. Biodiesel is a fascinating option, and it has been widely explored in recent decades due to specific advantages such as easy-to-obtain feedstocks (e.g., crude vegetable oils, and animal fats, etc.) for transesterification (as an easy conversion technique), biodegradability, less toxic impact on nature, etc. Vegetable oils derived from the seeds of the crops (generally from food and nonfood crops such as rapeseed, sunflower, soybean, switchgrass and jatropha) are used to convert them into methyl esters of fatty acids or precisely into biodiesel through a transesterification reaction (Folayan, Anawe, Aladejare, & Ayeni, 2019). However, in later times, it was discovered that the exploitation of energy crops to generate biodiesel was hampering economic stability and posing food security problems. Therefore crop residues such as leaves, stems, hulls, municipal and industrial waste, waste animal fats/lipids and microalgae, were seriously considered for biodiesel feedstock (Jaiswal, Banerjee, et al., 2021; Jaiswal, Dutta, et al., 2021; Jaiswal, Kumar, et al., 2021; Jaiswal & Pandey, 2014; Kumar et al., 2020; Kumar, Jaiswal, et al., 2021; Kumar, Yogeshwar, et al., 2021).

Aside from biodiesel, renewable diesel is another vital form of fuels that can be applied effectively as a fuel for automobiles. It has been manufactured maintaining the following standards: ASTM D975 and EN 590. It contains mainly long-, short- and branched-chain alkanes and negligible aromatic compounds. Similar triacylglyceride feedstocks involved in biodiesel production (especially vegetable oil) can also be utilized to generate renewable diesels by the catalytic hydrogenation method using the temperature range of 300°C–400°C together with pressures of ~100 atm. The hydrogenation or hydrotreating process involves the generation of hydrocarbons in the C15 glyph C18 range and eradicates oxygen, nitrogen and sulphur. Unlike biodiesel, renewable diesel has superior cleaner combustion and better cold flow characteristics (Singh, Subramanian, & Garg, 2018). A deeper analysis of renewable diesel showed few similar and excellent properties compared to petro-diesel. Still, it has numerous differences compared to biodiesel, elaborated in other sections.

1.3 Renewable diesel

Renewable diesel is the type of fuel generally obtained from various vegetable oils and possesses the properties analogous to petro-diesel fuels. Previously, the phrase ‘renewable diesel’ was used to identify the type of fuel produced from a renewable source without specifying any reference to the characteristic of the disel fuels generated. On the other hand, the phrase ‘green diesel’ considers the origin of the fuel and the impact on greenhouse gases due to its particular use. So the expressions ‘green diesel’ and ‘renewable diesel’ are much more complex (Bezergianni & Dimitriadis, 2013). In many cases, the interchangeable use of these terms was not entirely clear to make a precise distinction. However, recent studies have clarified the gap in understanding and have suggested their complementary use of the term (green diesel or renewable diesel) and, in addition, have labelled them as second-generation diesel or bio-hydrogenated diesel. Vegetable oils and fats as renewable sources are commonly used with catalytic hydroprocessing to produce renewable diesel. It should not be confused with biodiesel since most similar oils and fats are used to synthesise biodiesel through the transesterification reaction. Although, FAME or biodiesel formed from vegetable oils and/or animal fats can be utilized to generate low-range hydrocarbons and fuels that can easily be compared as almost equivalent to renewable diesel production. Using processes such as catalytic hydrodeoxygenation (HDO) or hydroprocessing reaction (along with steam cracking), the upgrading of FAME biodiesel derived from rapeseed or residual cooking oil to diesel as alkanes (C15 glyph C18) or suitable hydrocarbons (C2 glyph C4) have already been reported with optimised reaction parameters (Pattanaik & Misra, 2017).

Another way to produce renewable diesel from biomass feedstock is through the Fischer–Tropsch (FT) process. The FT process can effectively realise the syngas gas for further conversion of higher hydrocarbons. Furthermore, the beneficial factor of this process is that it can use a variety of feedstocks and constantly maintains the quality of the fuel. Mainly, this process was used to produce wood, natural gas and coal to produce hydrocarbons. Still, waste from the paper industry, cellulose and agricultural/forestry residues showed promising results in later times. The FT procedure to convert biomass into renewable diesel involves the following series of processes: syngas generation, catalytic conversion of syngas and finally, hydroprocessing (Douvartzides, Charisiou, Papageridis, & Goula, 2019). In addition, the FT process is classified according to the temperature range, where the low-temperature FT process includes a temperature range of 180°C glyph 250°C with the use of cobalt catalysts favourably. Besides, the high-temperature process is considered with a range of temperature to be 330°C glyph 350°C together with iron-based catalysts. These renewable diesels derived from the FT process are composed of low aromatic compounds. As a result, cleaner combustion can be achieved, specifically, reduced NOx emissions, making it better fuel for commercial use (Smagala et al.,