CHAPTER ONE

1.0   INTRODUCTION

1.1    Introduction

 Increasing demand for the production of energy from renewable sources has fueled a search for alternatives to supplement those currently in production. One such alternative is switchgrass, a perennial grass native to North America that appears to have considerable potential as a biomass feedstock for energy production (Duffield and Collins, 2006). The production of energy from renewable resources has been a national aspiration since the 1970’s. Since then, enthusiasm for renewable energy has largely waxed and waned in tune with fluctuations in real energy prices (Eidman, 2006). Studies have shown that the rate of global warming has risen to 0.2 ± 0.05 degrees centigrade per year (Hansen et al., 2006), a number which is alarming due to the capacity of ecosystems to withstand changes in temperatures of within 2 – 4.5 degrees centigrade before becoming unstable. Climate change is intensified by the release of certain chemicals into the atmosphere, known as greenhouse gases. These gases include carbondioxide, methane, and nitrous oxide, and are produced in high quantities by the burning of fossil fuels, such as coal and petroleum, fuels that are the source of the majority of the world’s energy demand and are non-renewable relative to the rate at which they are consumed. With the energy demand only growing higher, it is imperative to develop clean, renewable sources of energy (Bransby et. al. 1998, Cheng et. al. 2009). One source of renewable energy is bioethanol. Bioethanol is ethanol produced from fermentation of sugars extracted from plant matter (Bransby et. al., 1999).

Biomass encompasses all organic material that is available on a renewable or recurring basis, including wood and wood wastes, herbaceous plants/grasses, aquatic plants, manures and municipal wastes. Biomass is used to generate liquid fuels, primarily in the form of either ethanol from corn or biodiesel from vegetable oils and animal fats (Eidman, 2006). Biomass is also used to generate electricity, with wood wastes, forest residues, and municipal solid wastes serving as the primary feed stocks (Duffield, 2006). However, an increasing demand for renewable energy, attributable, in part, to the federal and state mandates discussed above, has prompted a search for alternative feed stocks. One such alternative is switchgrass (panicum virgatum). 

 The choice of biomass for bioethanol conversion should be decided on the basis of overall economics (lowest cost), environment (lowest pollutants) and energy (higher efficiency), i.e., comprehensive process development and optimization are still required to make the process economically viable. The increasing petroleum price and negative impact of fossil fuels on the environment are encouraging the use of lignocellulosic materials to help meet energy needs (Di Nasso et al., 2011). There are many advantages of biofuels over fossil fuels that make the alternative fuel source an attractive option now and in the future. The main advantage of biofuels is that they are considered ‘carbon neutral’ by some people. This is because the carbon dioxide released during the combustion of biofuels is equal to the amount that assimilated during photosynthesis (Kheshgi et al., 2000) resulting in no net increase to CO2 levels. Therefore, they don’t contribute to global warming. Consumption of biofuels releases no sulfur and has much lower particulate and toxic emissions, particularly when compared with other liquid transportation fuels (Scott and Wyman, 2004). Bioethanol production can provide an attractive route to dispose of problematic lignocellosic wastes such as stalks, stovers and leaves of agricultural crops. Ethanol is one of the most promising biofuels that can be used to replace gasoline for tomorrow’s transportation vehicles. Fuel ethanol is mainly used as an oxygenated fuel additive. The higher octane number of the fuel mixture, when it contains ethanol, reduces the need for toxic, octane-enhancing additives such as methyl tertiary butyl ether. Due to the oxygen in ethanol molecules, there is also a reduction of carbon monoxide emission and non-combusted hydrocarbons (Hu et al., 2008).

 Grassland scientists have conducted research on switch grass (Panicum virgatum) for more than 70 years, with initial research focusing on livestock and conservation. In 1936, L. C. Newell, an agronomist with the Bureau of Plant Industry, USDA, in Lincoln, Nebraska, began working with switchgrass and other grasses to potentially re-vegetate large areas of the central Great Plains and Midwest that had been devastated by the drought of the 1930s. The first switchgrass cultivar from this program was Nebraska 28 which was jointly released by USDA and the University of Nebraska in 1949. Since that time, establishment and management practices have been developed and refined, genetic resources have been evaluated, seed production has been improved, and a wealth of information has been made available to producers.

 In a frequently referenced Science article published in 1991, Lynd et al. hypothesized that given continued investment in research, by the year 2000, technology would be developed enabling the production of cellulosic ethanol for a wholesale selling price of $0.60 per gallon. 

Recently, the cultivation of switchgrass in Nigerian has been reported by Energy Development Commission Sokoto, the feasibility of switchgrass cultivation in Nigeria was adequately reported by the commission. Their worked shows that the plant can be cultivated in many states in Nigeria. Hence, production of bioethanol from switchgrass is viable in Nigeria.

1.2   Aim and Objectives

               The research is aimed at the production of ethanol from switch grass (Panicum Virgatum).

      The specific objectives are:

•        Production of bio-ethanol from switch grass using the acid hydrolysis, fermentation, and distillation process methods.

•        To determine the physical and chemical characteristics of the ethanol produced and compare with the literature review values.

1.3   Scope of the research

The scopes of the research work include the following:

•          Investigation on the production of bioethanol from switch grass.

•          Production of bioethanol using the Acid hydrolysis, fermentation and distillation process. 

•          Characterization of the ethanol produced.

•          Evaluation of the physiochemical properties of the produced bioethanol.

1.4   Problems Statement

 One of the biggest problems facing the world is the energy crisis. Increasing demand for the production of energy from renewable sources has fueled a search for alternatives to supplement those currently in production. One such alternative is switchgrass, a perennial grass native to North America that appears to have considerable potential as a biomass feedstock for energy production. While the properties of switchgrass as a biomass feedstock have been intensively studied, the potential market for switchgrass has received much less attention. The production of energy from renewable resources has been a national aspiration since the 1970’s. Since then, enthusiasm for renewable energy has largely waxed and waned in tune with fluctuations in real energy prices.

1.5   Research Justification 

 This research is necessary because the production of bio-ethanol from lignocellulosic biomass like switch-grass is a better choice than starch and sugar crops because of the comparative accessibility and abundance of forest, agricultural, and other cellulosic resources which do not compete with existing food chain. In addition, converting switchgrass into valuable product like ethanol provides potential benefits such as:

Producing energy from switch-grass rather than fossil fuels generates environmental benefits in the form of reduced atmospheric emissions of pollutants such as sulfur. Switchgrass also adds organic matter to soils, can help reduce erosion on highly erodible lands, and provides good forage and habitat for native wildlife. 

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