Bioenergy Research: Advances and Applications

Vijai G. Gupta, Maria Tuohy, Christian P Kubicek, Jack Saddler, Feng Xu, Vijai G. Gupta, Maria Tuohy, Christian P Kubicek, Jack Saddler, Feng Xu

• Publisher: Elsevier
• Year: 2013
• ISBN:
  9780444595645
• Topic: Technik & Maschinenbau
• Subtopic: Regenerative Energieressourcen

Bioenergy Research: Advances and Applications brings biology and engineering together to address the challenges of future energy needs. The book consolidates the most recent research on current technologies, concepts, and commercial developments in various types of widely used biofuels and integrated biorefineries, across the disciplines of biochemistry, biotechnology, phytology, and microbiology.

All the chapters in the book are derived from international scientific experts in their respective research areas. They provide you with clear and concise information on both standard and more recent bioenergy production methods, including hydrolysis and microbial fermentation. Chapters are also designed to facilitate early stage researchers, and enables you to easily grasp the concepts, methodologies and application of bioenergy technologies. Each chapter in the book describes the merits and drawbacks of each technology as well as its usefulness.

The book provides information on recent approaches to graduates, post-graduates, researchers and practitioners studying and working in field of the bioenergy. It is an invaluable information resource on biomass-based biofuels for fundamental and applied research, catering to researchers in the areas of bio-hydrogen, bioethanol, bio-methane and biorefineries, and the use of microbial processes in the conversion of biomass into biofuels.

• Reviews all existing and promising technologies for production of advanced biofuels in addition to bioenergy policies and research funding
• Cutting-edge research concepts for biofuels production using biological and biochemical routes, including microbial fuel cells
• Includes production methods and conversion processes for all types of biofuels, including bioethanol and biohydrogen, and outlines the pros and cons of each

Chapter 1

Current Bioenergy Researches

Strengths and Future Challenges

Naveen Kumar Mekala¹, Ravichandra Potumarthi^2,∗, Rama Raju Baadhe¹ and Vijai K. Gupta³, ¹Department of Biotechnology, National Institute of Technology, Warangal, Andhra Pradesh, India, ²Department of Chemical Engineering, Monash University, Clayton, Victoria, Australia, ³Molecular Glycobiotechnology Group, Department of Biochemistry, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland, ∗Corresponding author email: [email protected]; [email protected]

Abstract

Bioenergy is major stake holder in meeting global future energy needs. This contribution can be extended significantly in the near future, by reducing the greenhouse gas emission and saving environment, as well as improving trade balances, contributing to energy security, providing opportunities for socioeconomical development in rural areas. Bioenergy could sustainably offer a quarter and a third of global primary energy supply by 2050. Bioenergy is the only renewable source that can replace fossil fuels in all energy markets in the production of heat, electricity, and fuels for transport. Many bioenergy principles can be used to convert biomass feedstock into final bioenergy products. The technologies for producing heat and power from feedstock are already well defined and fully commercialized. A wide variety of conversion technologies are under construction, with improved competence, lower costs and improved environmental protection. However, the possible competition between raw materials for bioenergy with other biomass applications must be carefully answered. The output of biomass feedstock and food grains needs to be increased by good agricultural practices. Logistics and infrastructure issues should be spoken off, and there is need for further scientific innovations leading to more competent and cleaner conversion of more assorted feedstock.

Keywords

Anaerobic digestion; Biodiesel; Bioethanol; Biogas; Biofuel; Digesters; Fermentation; Transesterification

Outline

Introduction

Different Forms of Bioenergy

Biopellets

Bioethanol

Feedstock for Bioethanol

Pretreatment of Lignocelluloses

Biological Pretreatment

Physical Pretreatment

Chemical Pretreatment

Bioethanol Fermentation

Molecular Biology Trends in Bioethanol Production Development

Bioreactors in Ethanol Production

Immobilization of Cells for Ethanol Production

Biodiesel

Feedstocks for Biodiesel

Biodiesel from Pure Vegetable Oil

Biodiesel from Animal Fat Wastes

Other Waste Cooking Oils

Algae as a Biodiesel Source

Bioreactors for Biodiesel Production

Biogas

Biogas Feedstock

Household Digesters for Biogas

Fixed Dome Digesters

Floating Drum Digesters

Social and Environmental Aspects of Biogas Digesters

Conclusion

References

Introduction

Modern world is facing two vital challenges, energy crisis and environmental pollution. Energy is a key component for all sectors of modern economy and plays an elementary role in improving the quality of life (US DOE, 2010). In current situations, approximately 80% of world energy supplies rely on rapidly exhausting nonrenewable fossil fuels. At the current rate of consumption, crude oil reserves, natural gas and liquid fuels were expected to last for around 60 and 120 years, respectively (British Petroleum Statistical Review, 2011). An additional challenge with fossil fuel consumption is emission of greenhouse gases (GHGs). In 2010, an average of 450 g of CO₂ was emitted by production of 1 kWh of electricity from the coal (Figure 1.1) (International Energy Agency Statistics, 2012). It is also clear that coal's share of the global energy continues to rise, and by 2017 coal will come close to surpassing oil as the world's top energy source. China and India lead the growth in coal consumption over the next 5 years. Research says China will surpass the rest of the world in coal demand during the outlook period, while India will become the largest seaborne coal importer and second largest consumer, surpassing the United States (IEA, 2012).

FIGURE 1.1 Global energy production chart signifies the growing demand for energy. Source: IEA, 2012. (For color version of this figure, the reader is referred to the online version of this book.)

Growing global energy needs, release of environmental pollutants from fossil fuels and national security have finally tuned the attention in clean liquid fuel as a suitable alternative source of energy. The alternative bioenergy sources, not only cut the dependence on oil trade and reduce the doubts caused by the fluctuations in oil price, but also secure reductions in environmental pollution due to their high oxygen content (Huang et al., 2008; Boer et al., 2000).

In this context, the availability of bioenergy in its two main appearances, wood and agro energy can offer cleaner energy services to meet basic energy requirements. This century could see a remarkable switchover from fossil fuel-based energy to bioenergy-based economy, with agriculture and forestry as the main sources of feedstock for biofuels such as wood pellets, fuel-wood, charcoal, bioethanol, and biodiesel (Agarwal, 2007). Moreover, energy crops can be part of highly specialized and various agricultural production chains and biorefineries, where a variety of bioproducts could be obtained besides bioenergy, which are important for their economic competitiveness (United Nations Environment Program, 2006).

The exploitation of currently unused by-products and growing energy crops can address other existing environmental concerns. Perennial energy crops and plantations are generally characterized by higher biodiversity compared with conventional annual crops. By providing more continuous soil cover, they reduce the impact of rainfall and sediment transport, thereby preventing soil erosion. The introduction of annual energy crops into crop systems allows for diversification and expansion of crop rotations, replacing less favorable monocropping systems (Kheshgi et al., 1996). Deforested, degraded and marginal land can be rehabilitated with bioenergy plantations, thus helping to combat desertification and hopefully reducing market and geosocial pressures on high-quality arable land.

Biofuels can be obtained in bulk when they are derived from agricultural crops, crop residues and processing wastes from agroindustries, forests, etc. Despite this immense potential, existing biofuel policies have been very costly; they produce slight reductions in fossil fuel use and increase, rather than decrease, in GHG emissions (Wuebbles and Jain, 2001). However, recent volatility and rise in international fossil fuel prices, make biomass increasingly competitive as energy feedstock.

Current bioenergy research around the globe should direct us toward reduced production cost, higher energy conversion efficiency and greater cost-effectiveness of biofuels. After all we are aware of a fact “use of biomass as a potentially large source of energy in the 21st century will have a significant impact in rural, agricultural and forestry development” (UNEP, 2006).

Different Forms of Bioenergy

Organic matter holding bioenergy sources in side is known as biomass. We can utilize this biomass in many different ways, through something as simple as burning wood for heat, or as complex as growing genetically modified microbes to produce cellulosic ethanol (Adler et al., 2009). Since nearly entire bioenergy can be traced back to energy from sunlight, bioenergy has the key advantage of being a renewable energy source. Here, in this chapter we will discuss various forms of bioenergy and their application in detail.

Biopellets

Today, wood pellets are an imperative and well-accepted fuel in lots of different countries and the according markets are likely to rise even further in future. For these reasons, it is feared that the inadequate availability of cheap wood as a feedstock for pellets will limit this market increase (Marina et al., 2011; Larsson et al., 2008). As alternative, autumn leaves from urban areas, as a seasonal available waste material, are the possible substitutes for or additives to wood. In lot of Western countries, wood pellets become a more and more significant fuel for the use in small furnaces for household buildings or in industries as a climate-neutral alternative to crude oil or natural gas (Verma et al., 2012; Nielsen et al., 2009). This pelletized biomass has a number of advantages like tolerance against microbial degradation, high transport and storage density of bioenergy, and the process of pelletization is quite simpler (Figure 1.2).

FIGURE 1.2 (a) Experimental flow sheet for pelletization of leaves; (b) leaf pellets. (For color version of this figure, the reader is referred to the online version of this book.)

Bioethanol

Bioethanol is the most common biofuel worldwide. It is produced by simple fermentation of sugars derived from wheat, corn, sugar beets, sugarcane, molasses and any sugar or starch sources that alcoholic beverages can be made from (Cara et al., 2008). Bioethanol can be used in petrol engines as a substitute for gasoline. Bioconversion of lignocellulosics into fermentable sugars is a biorefining area in which enormous research labors have been invested, as it is a prerequisite for the subsequent bioethanol production (Broder et al.,...