CHAPTER ONE

1.0 INTRODUCTION

1.1 Background of the study

Biomass particularly agricultural residues seem to be one of the most promising

energy resources for developing countries (Patomsok 2008). Rural households and

minority of urban dwellers depend solely on fuel woods (charcoal firewood and

sawdust) as their primary sources of energy for the past decades (Onuegbu 2010).

Of all the available energy resources in Nigeria coal and coal derivatives such as

smokeless coal briquettes bio-coal briquettes and biomass briquettes have been

shown to have the highest potential for use as suitable alternative to coal/ fuel

wood in industrial boiler and brick kiln for thermal application and domestic

purposes. Global warming has become an international concern. Global warming is

caused by green house gasses which carbon dioxide is among the major

contributors. It was shown that increased emissions of CO

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have been drastically

reduced owing to the fact that the rate of deforestation is higher than the

afforestation effort in the country.

The use of fuel wood for cooking has health implications especially on women and

children who are disproportionately exposed to the smoke apart from

environmental effects. Women in rural areas frequently with young children

carried on their back or staying around them spend one to six hours each day

cooking with fuel wood. In some areas the exposure is even higher especially

when the cooking is done in an unventilated place or where fuel wood is used for

heating of rooms. Generally biomass smoke contains a large number of pollutants

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which at varying concentrations pose substantial risk to human health. Among

hundreds of the pollutants and irritants are particulate matters 1 2-butadiene and

benzene (Schirnding and Bruce 2002). Studies showed that indoor air pollution

levels from combustion of bio fuels in Africa are extremely high and it is often

many times above the standard set by US Environment Protection Agency (US-

EPA) for ambient level of these pollutants (USEPA 1997). Exposure to biomass

smoke increases the risk of range of common diseases both in children and in

adult. The smoke causes acute lower respiratory infection (ALRI) particularly

pneumonia in children (Smith and Samet 2000; Ezzati and Kammen 2001).

Agro waste is the most promising energy resource for developing countries like

ours. The decreasing availability of fuel woods has necessitated that efforts be

made towards efficient utilization of agricultural wastes. These wastes have

acquired considerably importance as fuels for many purposes for instance

domestic cooking and industrial heating. Some of these agricultural wastes for

example coconut shell wood pulp and wood waste can be utilized directly as

fuels.

Fortunately researches have shown that a cleaner affordable fuel source which is

a substitute to fuel wood can be produced by blending biomass (agricultural

residues and wastes) with coal. Nigeria has large coal deposit which has remained

untapped since 1950’s following the discovery of petroleum in the country. Also

millions of tones of agricultural wastes are generated in Nigeria annually. But it is

unfortunate that farmers still practice “slash-and-burn” agriculture.

These agricultural wastes they encounter during clearing of land for farming or

during processing of agricultural produce are usually burnt off. By this practice

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not only that the useful raw materials are wasted it further pollutes the

environment and reduces soil fertility.

On the other hand the majority of the huge materials are not suitable to be used

directly as fuel without undergoing some processes. This is probably as a result of

inappropriate density and high moisture contents and these factors may cause

problems in transportation handling and storage. Most of these wastes are left to

decompose or when they are burnt there would be environmental pollution and

degradation (Jekayinfa and Omisakin 2005). Researchers have shown that lots of

potential energies are abounding in these residues (Fapetu 2000). Hence there is a

need to convert these wastes into forms that can alleviate the problems they pose

when use directly. An assessment of the potential availability of selected residues

from maize cassava millet plantain groundnuts sorghum oil palm palm kernel

and cowpeas for possible conversion to renewable energy in Nigeria has been

made (Jekayinfa and Scholz 2009).

However these health hazard faced by people from the use of fuel wood along

with the agricultural wastes management and reduction of pressure mounted on the

forest can be mitigated if Nigeria will switch over to production and utilization of

bio-coal briquette; a cleaner and environmental friendly fuel wood substitute made

from agricultural wastes and coal. Moreover this will offer a good potential for

utilization of a large coal reserve in Nigeria for economic diversification and

employment generation through bio-coal briquette.

In countries like Japan China and India it was observed that agricultural waste

(agro residues) can also be briquetted and used as substitute for wood fuel. Every

year millions of tonnes of agricultural waste are generated. These are either not

used or burnt inefficiently in their loose form causing air pollution to the

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environment. The major residues are rice husk corn cob coconut shell jute stick

groundnut shell cotton stalk etc. These wastes provide energy by converting into

high-density fuel briquettes. These briquettes are very cheap even cheaper than

coal briquettes. Adoption of briquette technology will not only create a safe and

hygienic way of disposing the waste but turn into a cash rich venture by

converting waste into energy and also contributing towards a better environment.

Coal can be blended with a small quantity of these agricultural waste (agro

residues) to produce briquettes (bio-coal briquettes) which ignites fast burn

efficiently producing little or no smoke and are cheaper than coal briquettes.

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