ABSTRACT
The urgent need to protect our forest, to mitigate health
hazards faced by the people from the use of firewood for cooking and to find an
effective means of managing agro wastes has prompted a research on improving
the properties of coal briquette using spear grass (Imperata cylindrica)
and elephant grass (Pennisetum purpureum). In the research, proximate
analysis and the elemental composition of the plant materials were carried out
alongside with a coal sample. Briquettes of different composition were produced
by blending the plant materials with the coal at various concentrations: 0%,
10%, 20%, 30%, 40%, 50% and 100%. The physical, mechanical and combustion
properties of the briquettes were compared. It was found that the ignition,
burning rate and reduction in smoke emission showed improvement with increase
in biomass concentration. Compressive strength and cooking efficiency - water
boiling time and specific fuel consumption showed initial improvement and
rendered to break with briquette containing biomass concentration of 50% for
elephant grass briquette. For spear grass, the compressive grass was at maximum
at biomass concentration of 30%.
CHAPTER ONE
INTRODUCTION
1.1
Background of the Study
Nigeria, like other sub-Saharan
countries, has faced forest degradation problems due to combination of factors.
Some of the factors are clearing of land for agricultural and industrialization
purposes, over grazing, bush fires, drought, over exploitation, ever-
increasing deforestation along with the increased in the consumption of fuel
wood etc.
About 80% of Nigerians live in the
rural or semi-urban areas and they depend solely on fuel wood for their energy
needs. Fuel wood accounts for about 37% of the total energy demand of the
country. Investigations showed that out of the total wood demand from the
forest, 90% goes to fuel wood. Presently, Nigeria reportedly consumes about 43
x 109 kg of fuel wood annually [1] and it will be far more than this
by the end of 2010 if the present trend continues [2]. However, it is very
obvious that reduction in the use of fuel wood will drastically reduce the
pressure mounted on the forest in search of wood.
Meanwhile, it was reported that
the total forest cover of Nigeria is still less than 10% of the land area,
which is far below the 25% recommended by the United Nation Development
Programme (UNDP)
[2].
Therefore, it is imperative that
concerted efforts are needed to address this situation.
Furthermore, in the recent
years, 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 emission of CO2 in the
atmosphere in the recent time has exacerbated the global warming [3]. Part of
the reasons for this can be explained from the fact that the forest resources
which act as major absorbers of CO2 have been drastically reduced
owing to the fact that the rate of deforestation is higher than the
afforestation effort in the country.
Apart from environmental
effects, the use of fuel wood for cooking has health implications especially on
women and children who are disproportionately exposed to the smoke. Women in
rural areas frequently with young children carried on their backs 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 which at varying
concentrations pose substantial risk to human health. Among hundreds of the
pollutants and irritants are particulate matters, carbon monoxide, formaldehyde
and carcinogens such as benzo[α]pyrene, 1,2–butadiene and benzene [4]. 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
Environmental Protection Agency (US-EPA) for ambient level of these pollutants
[5].
Also, consistent evidence
revealed that exposure to biomass smoke increases the risk of a range of common
diseases both in children and in adults. The smoke causes acute lower
respiratory infection (ALRI) particularly pneumonia in children [6, 7]. Among
the women, it causes chronic bronchitis and chronic obstructive pulmonary
diseases (COPD) (Progressive and incompletely reversible air ways obstruction)
[8,9]. Eyes irritation (sore, red eyes, tears) from the smoke is also a common
experience in the use of fuel wood. A hospital based case – control studies
proved that a person exposed to smoke of biomass has high risk of cataracts
disease [10]. This evidence was further substantiated by an experiment carried
out on animals which showed that biomass smoke is capable of damaging eye lens
[11].
In the whole, it was summed up
that the total deaths attributed to the use of fuel wood in Nigeria are about
79,000. Also nearly 45% of the national burden diseases are related to solid
fuel use, according to a WHO Survey [2]. Again, combustion of raw
coal has equally been reported to have detrimental effects on both environments
and the health of the people. Among other effects, inhalation of coal smoke
increases the risk of lung cancer [12].
Frankly speaking, transition to
electricity or gas would have been the healthiest solution to these problems
but the likelihood of a complete transition in the poorer urban
and rural communities in the near future is minimal. Therefore it is pertinent
that other intervention measures especially ones recommended by WHO [4] should
be adopted to mitigate these health risks to the lowest possible level and
equally to relieve the forest resources from pressure mounted on it.
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 tonnes
of agricultural wastes are generated in Nigeria annually. But it is unfortunate
that farmers still practise “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, not only that
the useful raw materials are wasted, it further pollutes the environment and
reduces soil fertility.
Fire affects soil below ground
biodiversity, geomorphic process, and volatilizes large amount of nutrients and
carbon accumulated in the soil organic matter [13]. Furthermore, during process
of burning of agricultural wastes on the field, if it is not properly
controlled, it can inadvertently lead to bush fire, destroying further the
forest which has suffered much from the hand of wood seekers.
Forest fire is one of the
severe environmental problems in Nigeria and every year various forest types
are burnt as a result of fire set up deliberately or inadvertently through
careless or uncared acts. Forest fire destroys the fresh saplings, seedlings
and arrest regeneration of native species [13].
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 related SMEs.
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Item Type: Project Material | Size: 94 pages | Chapters: 1-3
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