ABSTRACT
This study aimed at predicting models and techno-economic analysis of biodiesel produced from neem seed oil using catalyst derived from animal waste bones as a heterogeneous catalyst. The animal waste bone was thermally activated. A total of 32 experiments was conducted to study the effect of methanol to oil molar ratio, catalyst concentration, reaction temperature, reaction time and agitation speed as obtained using RSM based on a two- level-five variable central composite designs (CCD).The optimum biodiesel yield of 92.5% was obtained at 6:1 methanol oil ratio, 4wt% catalyst 600C temperatures at reaction time of 4h and agitation speed of 350 rpm. The result showed that methanol to oil molar ratio, catalyst weight and temperature has significant effect on transesterification of neem oil to methyl ester. The regression model was found to be highly significant at 95% confidence level as correlation coefficients for R-Squared (0.9922), adjusted R-Squared (0.9780) and predicted R-Squared (0.8218). Techno-economic evaluation studies was conducted via Aspen Batch Process Developer (ABPD). The low cost of feedstock, methanol and catalyst reusability reduced the operating cost as well increases the profitability of the production process. The annual production cost was obtained as $3537105 at a payback time of 2.67years with IRR of 43% and NPV value of $900534. The sensitivity and profitability analysis of the project were evaluated and the project was observed to be economically viable. It was recommended that plant scale production of biodiesel production from neem seed oil should be undertaken to reduce the cost of biodiesel
TABLE OF CONTENTS
Cover page
Title page i
Declaration ii
Dedication iii
Certification iv
Acknowledgement v
Table of contents vi
List of tables x
List of figures xi
Abstract xii
CHAPTER ONE
1.0 INTRODUCTION 1
1.1 Statement of the Problem 5
1.2 Aims and Objectives of the Study 6
1.2.1 Aim 6
1.2.2 Objectives 6
1.3 Significance of the Study 7
1.4 Scope and Limitation of the Study 8
CHAPTER TWO
2.0 LITERATURE REVIEW 9
2.1 History of Biodiesel 9
2.2 Raw Materials for Biodiesel Production 12
2.2.1 Vegetable oil 12
2.2.2 Waste cooking oil 14
2.2.3 Animal fats 14
2.2.4 Algae 15
2.3 Biodiesel Production Methods 16
2.3.1 Micro-emulsion process 16
2.3.2 Pyrolysis 16
2.3.3 Direct use and Blending (dilution) 17
2.3.4 Transesterification reaction 18
2.4 Types of Catalyst Applied in Transesterification Reaction 19
2.4.1 Homogeneous catalysts 19
2.4.2 Homogeneous alkali catalysts 19
2.4.3 Homogeneous acid catalysts 20
2.4.4 Step wise acid and base transesterification 21
2.4.5 Heterogeneous catalysts 22
2.5 Biodiesel Production Process Technology 23
2.5.1 Microwave method 24
2.5.2 Ultrasonic method 24
2.5.3 Supercritical biodiesel production 25
2.6 Separation of Biodiesel from Byproducts 27
2.7 Purification of Biodiesel by Washing 28
2.8 Process Variables Affecting Biodiesel Production 28
2.8.1 Effect of methanol to molar ratio 28
2.8.2 Effect of catalyst concentration 29
2.8.3 Effect of reaction time and reaction temperature 30
2.8.4 Effect of agitation speed 30
2.8.5 Effect of co-solvent 30
2.8.6 Effect of moisture and free fatty acid 31
2.9 Biodiesel Specification and Properties 32
2.9.1 Physiochemical properties 33
2.9.1.1 Cetane number 33
2.9.1.2 Kinematic viscosity 34
2.9.1.3 Specific gravity 35
2.9.1.4 Iodine value 35
2.9.1.5 Density 36
2.9.1.6 Flash point 36
2.9.1.7 Acid value 37
2.9.1.8 Cloud point and pour point 37
2.9.1.9 Cold flow property 38
2.9.1.10 Water and sediment 38
2.9.1.11 Copper strip corrosion test 39
2.9.1.12 Sulphated ash test 39
2.9.1.13 Carbon residue 39
2.9.1.14 Phosphorus content 39
2.9.1.15 Sulphur content 40
2.9.1.16 Oxidation stability 40
2.9.1.17 Calorific value 40
2.9.1.18 Gas chromatography analysis (GC) 40
2.11 Neem Seed Oil 41
2.10.1 Socioeconomic importance of neem plant 42
2.11 Techno-Economic Analysis (TEA) 43
CHAPTER THREE
3.0 MATERIALS AND METHODS 45
3.1 Materials 45
3.2 Catalyst Preparation 45
3.2.1 Thermal activation 46
3.3 Catalyst Characterization Techniques 46
3.3.1 Scanning electron microscopy (SEM) 46
3.3.2 X-ray fluorescence (XRF) 47
3.3.3 Fourier transform infra-red (FTIR) 47
3.3.4 X-ray diffraction (XRD) 48
3.4 Transesterification Reaction Setup 48
3.5 Characterization of Neem Seed Oil 49
3.5.1 Determination of density/specific gravity 50
3.5.2 Determination of moisture content 50
3.5.3 Determination of iodine value 50
3.5.4 Determination of saponification value 51
3.5.5 Determination of acid value 52
3.5.6 Determination of free fatty acid (FFA) 52
3.5.7 Determination of ester value 53
3.5.8 Determination of peroxide value 53
3.5.9 Determination of viscosity 53
3.5.10 Determination of refractive index 54
3.6 Determination of Biodiesel Properties 54
3.6.1 Density of biodiesel sample 54
3.6.2 Kinematic viscosity at 40°C 54
3.6.3 Flash point of biodiesel 55
3.6.4 Pour point 55
3.6.5 Water content of biodiesel 55
3.7 Statistical Design of Experiments 56
3.8 Process Simulation of Biodiesel Production 58
3.8.1 Simulation approach using aspen batch process developer 58
3.8.1.1 Chemical component and utilities selection 59
3.8.1.2 Chemical reaction definition 60
3.8.1.3 Process recipe development 60
3.9 Economic Analysis 62
3.9.1 Sensitivity and profitability analysis 63
CHAPTER FOUR
4.0 RESULT AND DISCUSSION 65
4.1 Characterization of Neem Oil 65
4.2 Catalyst Characterization 69
4.2.1 Scanning electron microscopic (SEM) analysis 69
4.2.2 Fourier transform infrared spectrometer 70
4.2.3 X-ray diffraction (XRD) 72
4.2.4 X-ray fluorescence (XRF) 73
4.3 Biodiesel Properties 70
4.3.1 GC-MS result of methyl ester 76
4.3.2 Fourier transform infra-red spectroscopy of neem oil methyl ester 77
4.4 Development of Regression Model Catalyzed by CaO (Acid Activated Bone) 78
4.4.1 Model diagnostic plot 82
4.4.2 Response surface plots 83
4.4.3 Validation of the Optimization result 85
4.5 Techno-economic analysis of the biodiesel production 85
4.5.1 Process performance 85
4.5.2 Economic analysis 87
4.5.3 Sensitivity analysis 88
4.5.4 Profitability analysis 91
CHAPTER FIVE
5.0 CONCLUSION AND RECOMMENDATION 92
5.1 Conclusion 92
5.2 Research Recommendations 93
5.3 Contributions to Knowledge 94
REFERENCES
APPENDICES
LIST OF TABLES
2.1 Biodiesel specifications ASTM 6751-02 requirements 33
3.1 Experimental range and levels of the independent variables 56
3.2 Experimental design matrix for transesterification studies Central Composite Design (CCD) for five independent variables catalyzed by chemical, and physical activated catalyst 57
3.3 Chemical components used in the simulation process 59
3.4 Recipe for the process simulation of biodiesel from neem seed oil in ABPD 61
4.1 Physiochemical properties of neem oil 66
4.2 Fatty acid profile of neem seed oil, their corresponding retention times and percentage weight of the various peaks in the GCMS spectrum 67
4.3 Elemental weight compositions of thermal activated waste bones 74
4.4 Summary of the characterization of FAME property from neem oil 76
4.5 FTIR analysis of neem oil methyl ester by thermal activated waste bone 78
4.6 Experimental setup for 2-levels-5-five factors response surface design and the experimental values and predicted values for biodiesel production from neem oil. 79
4.7 ANOVA for Quadratic model for thermal activated waste bone methyl ester81
4.8 Result of model validation at the optimum conditions 85
4.9 Techno-economic parameters of heterogeneous biodiesel production from Azadirica indica oil 87
LIST OF FIGURES
2.1 Neem tree plantation 42
3.1 Process description of the biodiesel production 60
4.1 GCMS chromatogram of neem oil 66
4.2 FITR Spectrum of the sample (neem oil) showing the peaks
corresponding to different functional groups in the sample analyzed 68
4.3 SEM images of raw waste bone 69
4.4 SEM image of thermal waste bone 69
4.5 FTIR spectra of raw waste bone. 70
4.6 FTIR spectra of thermal activated waste bone. 70
4.7 XRD pattern of raw waste bones 72
4.8 XRD pattern of Thermal activated waste bones 72
4.9 X-ray fluorescence (XRF) of thermal activated waste bone. 73
4.10 GC-MS chromatogram of thermal activated waste bone FAME from neem oil 76
4.11 FTIR spectra of neem oil FAME by thermal activated catalyst 78
4.12. Plot of predicted values versus the actual experimental values for biodiesel yield catalyzed by acid activated CaO derived from waste bone 83
4.13 Three Dimensional Response Surface Plots for the Interaction Effect of Catalyst conc. (wt%) and methanol to oil ratio (mol/mol) against Yield. 84
4.14 3D diagram of the process performance of the biodiesel production 86
4.15 Effect of discount rate on payback time, ROI and IRR 89
4.16 Effect of biodiesel price on NPV, payback time, IRR and ROI 89
4.17 Effect of production cost on payback time, NPV, ROI and IRR 90
4.18 Profitability evaluation of biodiesel production using cumulative cash flow diagram (CCFD) 91
CHAPTER 1
1.0 INTRODUCTION
Depletion of petroleum reserves and increasing environmental concerns has resulted in greater demand for renewable fuels in recent years. The increasing demand for the petroleum based fuels has led to oil crises in the recent times. Therefore attention has been focused on developing the renewable or alternate fuels to replace the petroleum based fuels for transport vehicles. Biodiesel is the most promising renewable fuel which has attracted attention of researchers and industrialists in the world owing to its advantages over the conventional fossil diesel. It is non-toxic, biodegradable, renewable, considered as environmental friendly fuel due to its low carbon dioxide emissions with lower sulphur content. In addition, it reduces effect of greenhouse gasses due to less SO2, NO2, and CO2 gases emission (Demibras, 2009, Aderemi, et al. 2010).
Biodiesel also known as Fatty Acid Methyl Ester (FAME) is an environmentally friendly and renewable fuel which can be obtained by transesterification of vegetable oil or animal fats with alcohol using both homogeneous and heterogeneous catalysts (Razavi et al., 2019). Ethanol and methanol have been the common alcohols used in the trans-esterification of these oils to biodiesel using a base or an acid catalyst (Fereidooni et al., 2018). Alkali catalyzed transesterification has been most frequently used industrially, mainly due to its fast reaction rate (Ayhan, 2005, Freedman et al. 1986) The common homogeneous base catalysts for trans-esterification include sodium hydroxide (NaOH) and potassium hydroxide (KOH) (Tan, et al. 2015).
The challenge however, with the use of NaOH resulted to the formation of several byproducts mainly sodium salts which is treated as waste most times (Verma and Sharma, 2016) and also NaOH requires high-quality oil. Potassium hydroxide has an advantage over sodium hydroxide in that, at the expiration of the reaction, the reaction mixture can be neutralized with phosphoric acid resulting in potassium phosphate, which can be used as fertilizer. Alkaline-catalyzed transesterification proceed at considerably higher rates than acid catalyzed trans-esterification (Efeovbokhan et al., 2017).
The current feed stocks for production of biodiesel or mono-alkyl ester are vegetable oil, animal fats and micro algal oil. In the midst of them, vegetable oil is currently being used as a sustainable commercial feedstock. There are number of edible oil available in market such as sunflower oil, soya bean oil, cotton seed oil, coconut oil, ground nut oil from which preparation of biodiesel can be achieved. Edible oil used for biodiesel production results to the shortage of oil for cooking and consequently, the cost of oil becomes extremely expensive (Cao et al., 2020). In order to overcome these disadvantages, many researchers are interested in non-edible oils which are inappropriate for human consumption because of some poisonous components preset in the oils (Singh et al., 2017). Various non-edible oil such as jatropha oil (J. curcas), karanja oil (P. pinnata), Beef tallow oil, used frying oil, other waste oil and fats, Pongamia pinnate oil, Kokum oil, Mahua oil (M. indica), Simarouba oil, willed apricot oil , Jojoba oil ,Tobacco seed oil (N. tabacum L.), rice bran, mahua rubber plant (H. Brasiliensis), Kusum oil, linseed oil, castor oil, and microalgae, Neem oil (A. indica) and sal oil have been used for biodiesel production. But the production of biodiesel from these oils as feed stock varies as per their availability in different parts of the world.
Different researchers synthesized and used different kinds of solid wastes based catalysts (such as mollusk shells, eggshells, calcined fish scale, sheep bone, calcined waste bone) in order to produce cost effective catalysts and biodiesel (Jiang et al. 2015). Obadiah et al. (2012) worked on the production of biodiesel from palm oil using calcined waste animal bone as catalyst. The biodiesel yield was 96.78 % under optimal reaction conditions of 20 wt% of catalysts, 1:18 oil to methanol ratio, and 200rpm of stirring of reactants and at a temperature of 650C.
Among these solid wastes, animal bone is one of the best solid wastes that are easily and abundantly available all over the world. Although, the waste bone derived catalysts have shown a reasonable performance and constancy in the reaction, however these catalysts are required in high amount, high methanol/oil molar ratio with longer time for the reaction to occur. All these disadvantages make waste bone derived catalysts practically and economically unsuitable. To overcome these difficulties, it would be imperative to impregnate waste animal bones with other catalysts such as H2SO4/H3PO4 to make waste animal bone derived catalyst more active and to boost the surface chemical properties. Waste animal bones have proved to be highly effective as a catalyst support. The properties of calcined bone make it advantageous for use as catalyst support in transesterification reaction. It contains hydroxyapatite [Ca10 (PO4)6 (OH) 2], that is highly porous and also has a large surface area which allows catalyst to disperse over it largely and effectively. Calcined bones can also be used in high pressure and temperature reaction conditions.
Response surface methodology, a combination of mathematical and statistical techniques is widely used for designing experiments, building models, determining optimum conditions and evaluating the relative significance of several factors affecting a process (Kivanc and Yonten, 2020). The experimental work performed and reported in this paper was aimed at obtaining the optimal production conditions for transesterification of methyl ester from neem oil using base catalyst. The research objective was specifically to study the effect of the process parameters; methanol to oil molar ratio, catalyst weight, reaction time and temperature on transesterification of neem oil .The experiments were performed based on Central Composite Design (CCD) and Response Surface Methodology (RSM) was further used to analyze the relationship between the parameters and to determine the optimum conditions for optimal production of methyl ester of neem oil.
Developing an economical feasible biodiesel production process is essential in order to develop a sustainable biodiesel plant. (Lin et al., 2011; Lee et al., 2020). Techno-Economic Analysis (TEA) is one of the economic evaluation tools for different production processes which can be carried out using process simulators such as Aspen Plus (Hasas et al., 2006), Aspen Hysys, Aspen Batch Process Developer (ABPD), Superpro (Lee, et al., 2019; Lee et al., 2020). Economic analysis critically examines the production cost and techniques, the overall investment made directly and indirectly in the production process, the feedstock cost and availability, equipment required and their installation, buildings required for the production and the utilities such as electricity etc. required for the process (Rajendiran and Gurunathan, 2020). Hence, a techno-economic valuation of the optimized process parameters highlights the feasibility of the process technology (Longati et al., 2018).
This study focused on the production of biodiesel from neem seed oil using animal bone as a heterogeneous catalyst, optimization of the process parameters using CCD design in Response Surface Methodology (RSM) and techno-economic analysis using Aspen Batch Process Developer (ABPD®). ABPD® is used to simulate the biodiesel production process from neem seed oil. The data obtained from the simulation process were used for the economic evaluation and sensitivity analysis. Net present value (NPV), payback period and Return on Investment (ROI) were used in examining the techno economic suitability of the process.
1.1 STATEMENT OF PROBLEM
Globally, conventionally grown edible oils are the major feedstocks used for biodiesel production. This causes an imbalance between the utilization of energy sources and food consumption and contributes to the higher cost of biodiesel feedstocks. Also, the use of alkali or base catalyst, which is expensive, for transesterification enhances the production of soap as a side reaction which affects the quality of the biodiesel produced.
Based on the literature search, previous works on transesterification of Azadirica Indica oil to FAME focused black-box modelling studies, optimum operating conditions evaluation and process kinetics using various homogeneous and heterogeneous catalysts (Awolu and Layokun, 2013; Gurunathan and Ravi, 2015; Maran and Priya, 2015; Karmakar and Mukherjee, 2017; Adepoju, 2020; Inayat et al., 2020). However, basic engineering endeavors such as computer-aided batch process simulation, economic and profitability feasibility studies of Biodiesel Production from Azadirica indica Oil (BPAIO) were scarcely found in the pool of scientific literature despite the commercialization prospect of BPAIO in most of developing countries.
Computer-aided simulation mimics chemical processes and performs material flow balance, process scale-up as well as equipment sizing of the unit operations involved in the process. Developing an economic feasibility study of biodiesel production process is essential in order to develop a sustainable and profitable biodiesel production plant. (Kookos, 2018). Techno-Economic Analysis (TEA) is an essential tool used in investigating the technical and economic performance of production processes; TEA technique has been performed for various processes in order to evaluate the feasibility of process technologies via commercial process simulators such as Aspen Plus, Aspen Hysys, Aspen Batch Process Developer (ABPD), Superpro designer (Adeniyi et al., 2019; Lee et al., 2020; Liu et al., 2021; Oke et al., 2021). Process techno-economic analysis critically examines the overall investment and profit made directly and indirectly in the production process, the feedstock cost, equipment and their installations, buildings required for the production and also the utilities required for the process (Liu et al., 2021). The present study is aiming at bridging the lacuna found in the previous works on BCBPAIO by modelling, optimizing and techno-economic evaluation of the production process.
1.2 AIM AND OBJECTIVES OF THE STUDY
1.2.1 Aim
The aim of this study is to develop predictive modelling, experimental optimum conditions and techno-economic analysis for biodiesel production from neem oil.
1.2.2 Objectives
The objectives of the research study are:
i. To characterize the Neem oil using gas chromatography and mass spectroscopy, Fourier Transform Infrared.
ii. To produce biodiesel using methanol in the presence of heterogeneous solid base catalysts (CaO derived from catttle waste bone).
iii. To establish optimal conditions for biodiesel production by considering methanol/oil mole ratio, catalyst concentration, reaction time, temperature and agitation speed using Response Surface Methodology.
iv. To characterize the biodiesel using the ASTM, FTIR and GCMS
v. To develop base case and scale up simulation models for heterogeneous neem oil biodiesel production
vi. To perform techno-economic analysis of neem oil biodiesel production
1.3 SIGNIFICANCE OF THE STUDY
i. Production of biodiesel from neem oil will reduce total reliance on petroleum and crude oil products.
ii. Biodiesel production will create employment for the unemployed in the rural area in the form of economic growth.
iii. It will increase the income earning power of Nigerian farmers especially in neem seed plantation.
iv. Producing neem oil diesel will increase our export value and resource diversification.
v. It will help in the conservation of the non-renewable source of energy, the fossil fuel.
vi. It will improve the revenue generation of Nigeria since it does not require hydrocarbon deposit for its production.
vii. Neem oil biodiesel will reduce the pollutant emission in the country since it has low emission when compared with the existing fossil fuel, thereby solving the problems of atmospheric pollution in the country.
viii. Producing biodiesel from neem oil will alleviate the problems of oil spillage in the Niger Delta as pressure will be reduced on the fossil fuel.
ix. Economic analysis of the production will aid to establish the profitability feasibility of the production process
1.4 SCOPE AND LIMITATION OF THE STUDY
Research work was delimited to the trans-esterification of neem oil. The determination of the molecular weight of the oil triglycerides was based on the fatty acids profiles obtained from Gas Chromatography system. Methanol was the only alcohol considered during trans-esterification process, and the catalyst used was thermally activated CaO derived from waste bone, optimization of the process parameters of the produced biodiesel and techno economic analysis of the transesterification process.
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