ABSTRACT
A fixed bed pyrolysis system has been designed and constructed for obtaining liquid fuel
from palm kernel shell. The major components of the system are: fixed bed reactor and
condensate unit. The palm kernel shell in particle form was pyrolized in an externally
heated 90mm diameter and 360mm high fixed bed reactor. The reactor is heated by means
of a rectangular shape manual forge blower with charcoal as the energy source. The
products are char, oil and gas. The parameters varied are feed particle size, reactor bed
temperature and running time. The reactor bed temperature was found to influence the
product yields. The maximum liquid yield was 38.67wt % at 4500C for a feed particle size
of 1.18mm with a running time of 95minutes. The maximum char yield was 70.67wt% at
5500C for a feed particle size of 5mm with a running time of 120minutes. The calorific
value of the palm kernel shells (22.81 MJkg-1) and bio-oil (43.19MJkg-1) were determined.
The reactor efficiency was evaluated at various temperatures. Maximum efficiency of
73.21% indicated that the reactor is efficient enough to produce bio-oil. The bio-oil
products were analysed by Fourier Transform Infra-red Spectroscopy (FTIR) and Gas
Chromatography Mass Spectrometry (GCMS). The FTIR analysis showed that the bio-oil
was dominated by phenol and its derivatives. The phenol, 2-methoxy-phenol and 2, 6-
dimethoxyl phenol that were identified by GCMS analysis are highly suitable for
extraction from bio-oil as value-added chemicals. The highly oxygenated oils need to be
upgraded in order to be used in other applications such as transportation fuels.
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TABLE OF CONTENTS
DECLARATION ii
CERTIFICATION iii
DEDICATION iv
ACKNOWLEDGEMENT v
ABSTRACT vi
LIST OF FIGURES xi
LIST OF TABLES xiii
LIST OF PLATE xiv
LIST OF APPENDICES xv
NOMENCLATURE xvi
CHAPTER ONE: INTRODUCTION
1.1 Background of the Study 1
1.2 Statement of the Research Problem 2
1.3 The Present Research 3
1.4 Aim and Objectives of the Research 3
1.5 Justification of the Study 3
1.6 The Scope of the Research 4
CHAPTER TWO: LITERATURE REVIEW
2.1 History of Pyrolysis 5
2.2 Principle of Pyrolysis 5
2.2.1 Slow Pyrolysis 7
2.2.2 Fast Pyrolysis 8
2.2.3 Flash Pyrolysis 9
2.3 Pyrolysis Reactor 9
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2.3.1 Fixed Bed Reactor 10
2.3.2 Fluidized Bed Reactor 11
2.3.2.1 Bubbling Fluidized Bed Reactor 11
2.3.2.2 Circulating Fluidized Bed Reactor 12
2.3.3 Ablative Reactor 13
2.3.4 Vacuum Pyrolysis Reactor 14
2.3.5 Rotating Cone Reactor 15
2.3.6 Pyros Reactor 16
2.3.7 Auger Reactor 17
2.3.8 Plasma Reactor 18
2.3.9 Microwave Reactor 19
2.3.10 Solar Reactor 20
2.4 Factors Affecting Pyrolysis of Biomass 21
2.4.1 Feedstock Composition 22
2.4.2 Feedstock Preparation 23
2.4.3 Pyrolysis Temperature Control 24
2.4.4 Residence Time 26
2.4.5 Moisture Content 26
2.5 Biomass 27
2.5.1 Biomass Conversion Technology 28
2.5.2 Feed stock/ material background 29
2.6 Fourier Transform infra-red (FTIR) 30
2.7 Gas Chromatography/ Mass Spectroscopy (GC-MS) 30
2.8 Review of related past works 31
2.9 Research gap 34
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CHAPTER THREE: MATERIALS AND METHODS
3.1 Materials 35
3.1.1 List of Materials 35
3.2 Methods 36
3.2.1 Description of the fixed pyrolysis system 36
3.2.2 Design Theory and Equation 37
3.2.2.1Initial design parameters 37
3.2.2.2 Stresses in the fixed bed reactor 38
3.2.2.3 Reactor Thickness 39
3.2.2.4 Insulation 39
3.2.2.4.1Insulation Thickness 39
3.2.2.5 Design of the Reactor 42
3.2.2.6 Design of the Condenser 45
3.2.2.7 Design calculation of the fixed bed pyrolysis system 48
3.2.3 Construction of the fixed bed pyrolysis system 51
3.2.4 Assembly of the pyrolysis system 53
3.2.5 Experimental procedure 55
3.2.5.1 Preparation of Feedstock 55
3.2.5.2 Operational procedures of the fixed bed pyrolysis system 55
3.2.6 Characterization of Palm kernel Shells (PKS) 56
3.2.6.1 Proximate analysis of PKS 56
3.2.6.2 Ultimate analysis of palm kernel shell 57
3.2.6.3 Determination of the calorific value of the palm kernel shell 57
3.2.7 Performance evaluation of the fixed bed pyrolysis system 58
3.2.8 Effect of pyrolysis parameters 59
3.2.8.1 Effect of particle size 59
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3.2.8.2 Effect of temperature 59
3.2.8.3 Effect of running time 59
3.2.9 Characterization of bio-oil 59
3.2.9.1 Ultimate analysis of the bio-oil 60
3.2.9.2 Determination of the calorific value of the bio-oil 60
3.2.9.3 Fourier Transform infra-red (FTIR) 60
3.2.9.4 Gas Chromatography/ Mass Spectroscopy (GC-MS) 60
CHAPTER FOUR: RESULTS AND DISCUSSION
4.1 Characterization of palm kernel shells (PKS) 62
4.2 Variation of pyrolysis parameters 63
4.2.1 Effect of Particle Size 63
4.2.2 Effect of Temperature 65
4.2.3 Effect of Running time 67
4.3 Performance evaluation of the fixed bed pyrolysis system 68
4.4 Characterization of bio-oil product 69
4.4.1 Ultimate analysis of the bio-oil 69
4.4.2 FTIR analysis of bio-oil 69
4.4.3 GCMS analysis of the Bio-oil 70
4.5 Cost Estimate 72
CHAPTER FIVE: CONCLUSIONS AND RECOMMENDATIONS
5.1 Conclusions 74
5.2 Recommendations 75
5.3 Significant Contributions 75
REFRENCES 77
APPENDICES 86
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CHAPTER ONE
INTRODUCTION
1.1 Background of the Study
Uninterrupted energy supply is a vital issue for all countries today. Future economic
growth crucially depends on the long-term availability of energy from sources that are
affordable, accessible, and environmentally friendly. Security, climate change, and public
health are closely interrelated with energy (Ramchandra and Boucar, 2011). The standard
of living of a given country can be directly related to the per capita energy consumption.
The recent world’s energy crisis is due to two reasons: the rapid population growth and the
increase in the living standard of societies. The per capita energy consumption is a measure
of the per capita income as well as a measure of the prosperity of a nation (Chikaire et al.,
2015).
Energy supports the provision of basic needs such as cooked food, a comfortable living
temperature, lighting, the use of appliances, piped water or sewerage, essential health care
(refrigerated vaccines, emergency and intensive care), educational aids, communication
(radio, television, electronic mail, the World Wide Web), and transport. Energy also fuels
productive activities including agriculture, commerce, manufacturing, industry, and
mining. Conversely, lack of access to energy contributes to poverty and deprivation and
can contribute to the economic decline. Energy and poverty reduction are not only closely
connected with each other, but also with the socioeconomic development, which involves
productivity, income growth, education, and health (Nnaji et al., 2010).
The high rate of extracting the crude oil from the earth-crust demands for an alternative
and dependable source of obtaining energy (Rajput, 2005). This alternative is the energy
derived via pyrolysis (a thermal decomposition process that occurs at moderate
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temperatures with a high heat transfer rate to the biomass particles and a short hot vapour
residence time in the reaction zone) of agricultural and forest residues (generally called
biomass). Biomass has been recognized as a major renewable energy source to supplement
declining fossil fuel sources of energy. It is the most popular form of renewable energy and
currently biofuel production is becoming very much promising. Transformation of energy
into useful and sustainable forms that can fulfil and suit the needs and a requirement of
human beings in the best possible way is the common concern of the scientists, engineers
and technologists. In this contest, bio fuels can be realised through fixed bed pyrolysis
system using palm kernel shells as biomass. Fixed bed pyrolysis is more attractive among
various thermo-chemical conversion processes because of its simplicity and higher
conversion capability of biomass and solid wastes to yield char, liquid and gases (Hossain
et al., 2014).
1.2 Statement of the Research Problem
From the literature reviewed, it is obvious that a lot of research works have been conducted
on fixed bed pyrolysis system powered by electric heater. However, it is obvious from the
review that fixed bed pyrolysis system powered by electric heater can only be efficiently
used where there is steady electricity supply which is the major limitation of this system
(especially in Nigeria).
The use of stainless steel for the construction of the reactor has a significant effect on the
cost of the pyrolysis products. Therefore, there is a need to source for alternative material
to minimize the cost at optimum production.
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1.3 The Present Research
The current work focuses on the design, construction and performance evaluation of a
fixed bed pyrolysis system, which will use palm kernel shells to produce bio-fuels. The
bio-oil produced can then be used to generate heat and power from small stationary diesel
engines, gas turbines and boilers. The agricultural by-products include maize cobs,
groundnut shells, palm kernel shells, rice and millet husks, millet stalks, sorghum stalks,
sugar cane bagasse, maize stalks and cotton stalks among others. However, this research
will focus on palm kernel shells because of its availability.
1.4 Aim and Objectives of the Research
The aim of this research is to design and construct an externally heated fixed bed pyrolysis
system for the production of alternative liquid oil from palm kernel shells.
Therefore, the specific objectives of this research are to:
i. design a fixed bed pyrolysis system.
ii. construct the fixed bed pyrolysis system.
iii. evaluate the performance of the fixed bed pyrolysis system to determine its
effectiveness in bio-oil production.
iv. characterise the bio-oil produced from the fixed bed pyrolysis system using
FTIR and GCMS analyses.
1.5 Justification of the Study
Nigeria is blessed with abundant renewable energy resources such as hydroelectric, solar,
wind, tidal, and biomass, there is a need to harness these resources and chart a new energy
future for Nigeria. To enhance the developmental trend in the country, there is every need
to support the existing unreliable energy sector with a sustainable source of power supply
through pyrolysis of biomass.
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There are several benefits of introducing electricity to rural communities. While obvious
reasons include social gains like lightening, cooking and water pumping, electricity will
help to stem the flow of rural-urban migration which is a common problem in many
developing countries like Nigeria. Introduction of electricity also helps to provide
productive employment in rural areas thereby creating a positive impact on economic as
well as social growth. Fixed bed pyrolysis when combined with a boiler can provide
efficient and affordable source of energy thereby boosting rural education and
development, since it uses agricultural waste as a fuel source. Bio-oil generated can either
be used for electricity production in a gas turbine or generate steam in a boiler.
1.6 The Scope of the Research
The scope of this research is:
i. Design, construction and performance evaluation of a fixed bed pyrolysis
system, which will use palm kernel shells as feed materials to produce biofuels.
ii. The emphasis of the study is on the production of a liquid fuel from 1.5kg per
sample of palm kernel shells using fixed bed pyrolysis system. The char
product will be also quantified.
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