The Production Of Smokeless Fuel From Sawdust Using Briquetting Machine

ABSTRACT

Energy is a key requirement for socioeconomic development. However, the utilization of energy must not be at the expense of the environment and the future. One way of reducing dependence on biomass as a source of energy is to promote the use of briquettes by homes and industries. The pressure on the environment for fuel wood and the indiscriminate felling of trees leading to deforestation has led to the research of alternative energy sources. Saw dust produced from wood mills is mostly treated as waste materials. This study examined the feasibility of establishing and managing a briquette manufacturing plant. This research work is aimed at using this saw dust to produce smokeless fuel.

 TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER ONE

1.0     INTRODUCTION

• BACKGROUND OF THE PROJECT
• AIM OF THE STUDY
• OBJECTIVE OF THE PROJECT
• PURPOSE OF THE PROJECT
• SCOPE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• BENEFIT OF THE PROJECT

CHAPTER TWO

LITERATURE REVIEW

• OVERVIEW OF FUEL-WOOD
• SOURCE AND USAGE OF FUEL-WOOD
• CONSEQUENCES OF FUEL-WOOD USAGE
• DEFORESTATION
• DESERTIFICATION
• SOIL EROSION
• REVIEW OF OTHER ALTERNATIVES TO FUEL-WOOD

CHAPTER THREE

• MATERIAL AND METHOD
• COLLECTION OF BRIQUETTE MAKING MATERIALS
• PREPARATION OF BRIQUETTES
• PREPARATION OF BRIQUETTES USING MIXTURE OF SAWDUST AND RICE CHAFF
• STUDY OF THE BRIQUETTES

CHAPTER FOUR

• RESULTS AND DISCUSSIONS
• PHYSICAL CHARACTERISTICS OF THE BRIQUETTES
• DISCUSSION

 CHAPTER FIVE

DISCUSSION, CONCLUSION AND REFERENCES

• DISCUSSION
• CONCLUSION
• REFERENCE

 CHAPTER ONE

1.1                                                  INTRODUCTION

Nigeria has abundant supplies of biomass resources, particularly agro- forestry residues and municipal solid waste, whose potentials are yet to be fully tapped for energy generation. Conventionally, wood (fuel wood), twigs and charcoal have been the major source of renewable energy in Nigeria, accounting for about 51% of the total annual energy consumption. The other sources of energy include natural gas (5.2%), hydroelectricity (3.1%), and petroleum products (41.3%) (Akinbami, 2001). The demand for fuel wood is expected to have risen to about 213.4 x103 metric tonnes, while the supply would have decreased to about 28.4 x103 metric tonnes by the year 2030 (Adegbulugbe, 1994). The declining availability of fuel wood, coupled with the ever-rising prices of kerosene and cooking gas in Nigeria, is creating a human and environmental crisis in developing countries such as deforestation, desertification, soil erosion, ozone depletion etc. These gave rise to the need to consider alternative sources of energy for domestic and small level industrial use in the country. As rightly noted by Stout and Best (2001), a transition to a sustainable energy system is urgently needed in the developing countries such as Nigeria. Such energy sources should be renewable and should be accessible to the local. An energy source that meets such sustainability requirements is the fuel briquette.

A briquette is a block of flammable matter produced from various types of materials such as saw dust, water hyacinth, food and animal garbage’s and agricultural residues which is used as fuel to start and maintain a fire (Olorunnisola, 1998). Briquettes are similar to wood pellets, but physically larger, compressed and dried to form a virtually smokeless, slow burning, easily stored and transported fuel. They also can be prepared in different shapes, sizes and form: those with holes through the centre, and those in solid form. The solid briquette is manufactured using a locally-made piston press which binds the materials together. The hole is simply a byproduct of the piston thread passing through the center; however it also increases the surface area of the log and aids efficient combustion.

1.2                                     BACKGROUND OF THE STUDY

The need for renewable and sustainable alternative energy sources are growing due to the rapid depletion of the non-renewable fossil energy resources and the negative impacts of the increasing prices of these fuels on the developing economies. In this respect, biomass is of great interest because of its miscellaneous advantages such as easily finding, low price, carbon dioxide neutral feature, and very high worldwide potential.

Agricultural and forest residues, industrial wastes, municipal solid wastes (MSW), and refuse derive fuels (RDF) are the well-known types of the biomass energy resources which are numerous in number.

However, direct combustion of biomass is not preferable because of the negative aspects coming from the intrinsic properties of biomass such as low density, low calorific value in a unit volume, and high moisture, etc.

From this point of view, it is important to develop strategies by which biomass is converted to secondary fuels which have better characteristics in comparison to the parent material. On the other hand, in order to reduce the environmental pollution risks of such fuels, some precautions must be taken. In this context, production of smokeless fuel briquettes from biomass which have quite high calorific value and almost hardly any volatile matter is a reasonable technique to take advantage of the energy potential of biomass in environmental friendly way. For this purpose, biomass is first carbonized to eliminate the moisture and volatile matter contents and then the volatile matter-free solid char, which is called as “smokeless fuel”, is briquetted to form firm bio-fuel briquettes. It is reported in literature that serious increases take place in the calorific value of the product owing to the elimination of the volatile matter, leaving a solid product having higher carbon content [1]. Furthermore, transportation and storage costs are apparently lowered as a result of the densification of biomass. Consequently, a non-polluting solid fuel which can be competitive with coal with respect to calorific value can be produced applying this procedure.

In order to improve the mechanical strength of the bio-briquettes, some additives and binding materials are added to biomass and they are briquetted together in the same briquetting mold. For this purpose, various additives such as humates, molasses, H₃PO_4, and sulphite liquor have been used in briquetting.

It is reported in literature that the exothermic reaction of some binders such as molasses and lime during briquetting provides the removal of the moisture in the briquettes [2].

Blesa et al. reported that carbonization of coal and olive husks at 600ºC and then briquetting of the chars from carbonization with molasses under pressure of 125 MPa shows the best mechanical strength when they are waited for 2 hours at 200ºC [3]. Besides, the optimum carbonization temperature for low rank coals was found as 600ºC [4].

Similarly, mechanically durable fuel briquettes could be produced from low rank coal char and sawdust char in the presence of humiliates under a briquet-ting pressure of 125 MPa [5].

Briquet ting of coal and some biomasses such as sawdust using the binders of humates and Ca(OH)₂ at ambient temperature under 125 MPa gave the best results when the feedstock materials were subjected to heating up to 160ºC with a rate of 2ºC/min prior to briquetting [6].

Also, it is reported that the water resistance for the coal briquettes which obtained under 125 MPa using some binders such as humates and sugar cane was very satisfactory [7].

Coal and olive husks were carbonized at 600 ^ºC to be used in the production of durable briquettes under 125 MPa using a binding agent which contains humates (6%) and sugar (16%) [8].

Mayoral et al. determined that the briquetting of a smokeless fuel that obtained from the carbonization of coal and olive husks at 600ºC gave very good results in terms of mechanical strength when the briquet-ting was performed under 125 MPa and at 200ºC using sugar cane as a binder [9].

1.3                                             AIM OF THE PROJECT

The aim of this study is to carbonize a biomass source which is a different type of biomass material, and then usage of molasses and an alternative binding agent such as the pyrolytic liquor which is obtained from the carbonization of biomass as a liquid product. Sawdust have been selected as biomass  material  due  to  its  potential  in  Nigeria.  In fact, Nigeria supplies nearly 75% of world sawdust production and consequently a great amount of woody shells are obtained every year.

1.4                                      OBJECTIVES OF THE PROJECT

This project is undertaken with the following objectives:

1. Produce briquettes using sawdust and combination of sawdust and agricultural waste which are very good materials for briquetting due to their binding properties coupled with its relatively high calorific value (between 13-20 MJ/Kg) and relatively low ash content (Jekayinfa and Omasakin, 2005).
2. Compare the cost and economic benefits of using briquette to other sources of

• Check if there are any health hazards or environmental effects of briquette production and use especially as regards smoke

1. To convert cheap or waste fine coal into lump fuel; to produce from coal(s) which decrepitates on grate, solid fuel (smokeless fuel) that can behave satisfactorily during combustion. The briquette smokeless fuel can be produced from all rank of coals (except anthracite) of good grade (less ash and sulphur). Briquette can also be prepared by compacting pulverized coal or biomass with addition of binder and sulphur fixation agent [5], made into different shape and size for convenient application. Carbonization of the coal briquette at low and high temperature produces smokeless fuel and industrial coke respectively.

1.5                                          PURPOSE OF THE STUDY

The main purpose of briquetting material is to reduce the volume and thereby increasing the energy density. When densification takes place, there are two quality aspects that need to be considered, firstly, the briquette has to remain in solid form until it has served its purpose (handling characteristics). Secondly, the briquette has to perform well as a fuel (fuel characteristics). The energy characteristics are other important issues when describing and comparing briquettes with other fuels [6]. The energy characteristics describe how the briquette act and what it produces when burned. The calorific value of briquettes is an important measure of the amount of energy released from every briquette when burned. Briquettes are normally priced by weight, but still, the calorific value is the most important factor in determining the competitiveness of the fuel. The calorific value varies with ash content and moisture content.

1.6                                             SCOPE OF THE STUDY

Sawdust which is a high potential biomass species in Nigeria was carbonized in a horizontal tube furnace at 600ºC to eliminate the volatiles and to obtain smokeless burn. Then, the solid product was briquetted in a stainless steel mold using a hydraulic press under pressure of 50-100 kg/cm². In order to improve the mechanical strength of the bio-briquettes molasses and the pyrolytic liquid that obtained during carbonization was used as binding agents. Some parameters such as Shatter index, compressibility strength, and water resistance were considered to evaluate the strength of the briquettes.

1.7                                     SIGNIFICANCE OF THE STUDY

The smokeless fuel in particular is a kind of economical and efficient combustible that can burn averagely for 8 hours with good heat productivity. It burns with azure (deep blue) colour and no or little flue-gases emission [8]. It is ideal or perfectly suitable for use in its customised stove, multi-fuel stove or open fire; and has high efficiency that burns for up to 40 % longer than the raw coal, producing 80 % less smoke and 25 % less carbon dioxide – CO₂ [9] emission during combustion in line with global concern. Generally, smokeless fuel briquette is a kind of fuel that has an extensive use in the average home for cooking meal, warming bathing water and heating residential house during winter; restaurant, hotel and school dining hall for meal preparation; poultry farm for brooding chicken and cottage industry as energy source.

The smokeless fuels (coke fuels) produced are generally good because of their high calorific values, strong to some extent for safe handling, ignite easily because of the perforated holes without any danger, generate less smoke and less ash (dust).

The chemical properties with the exception of the volatile matter content that influence the coke fuel behavior and reaction during heat treatment in a boiler are generally appreciable in the briquette fuels produced.

These briquettes have been confirmed to burn in an average time of 2.5 hours. It is hoped that this study will mobilize local entrepreneurs to invest in the production of smokeless fuel for domestic and industrial use as an addition to energy mix as well as reduction of ecological devastation, ensuring complete briquet ting of the raw material(s) into fire susceptible shape for easy ignition. The use of briquettes as energy source can provide jobs for local residents besides of the advantages of the briquette itself.

1.8                                           BENEFIT OF THE STUDY

Processing of sawdust into smokeless fuel has a lot of benefits:

1. protects the environment,
2. generates income and employment,
3. saves time,
4. saves energy