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    populnea GUM AS BINDER



    B.Sc. (Hons) Mechanical Engineering (Ibadan),

    M.Sc. Agric. Engineering (Farm Power and Machinery), Ibadan

    A Thesis in the Department of


    Submitted to the Faculty of Technology

    in partial fulfilment of the requirements for the Degree of DOCTOR OF PHILOSOPHY of



    Department of Mechanical Engineering

    The Polytechnic, Ibadan.

    NOVEMBER, 2012

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    We certify that this study was carried out by Engr. T.I. Oyedemi in the Department of

    Agricultural and Environmental Engineering, Faculty of Technology, University of Ibadan,





    B.Eng.(Hons) Akure; M.Sc. Ph.D (Ibadan)


    Professor in the Department of Agricultural and Environmental Engineering.




    B.Pharm. (Ife); M.Sc., Ph.D (Ibadan)

    Professor in the Department of Pharmaceutics and Industrial Pharmacy

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    Large quantities of agricultural and mill residues which are generated annually in Nigeria

    constitute environmental health hazards. Densification of these residues which is a major way of

    converting them to high quality fuel has not been adequately studied in Nigeria. The objective of

    this study was to develop and evaluate a system for briquetting and combusting Gmelina arborea

    sawdust and maize cob particles.

    Gmelina arborea Sawdust (GS) was obtained from a small-scale sawmill in Ibadan while

    maize cobs were obtained from Oja – Oba market, Ibadan and milled. Moisture Contents (MC)

    and Bulk Densities (BD) of GS and Maize Cob Particles (MCP) were determined. Gum extracted

    from Cissus populnea stems was evaluated for its suitability as binding agent for fuel briquettes.

    The viscosity of the crude gum powder was determined at concentrations of 1-10 % (w/v). A

    manual briquetting machine and a briquetting stove were developed and evaluated. Briquetting

    of the GS and MCP was done at gum concentrations of 1-30 % (w/w) and pressure levels of 1.5-

    5.0MPa using 0.6 mm fine and 1.18 mm coarse particles. Briquette stability was measured in

    terms of linear expansion with time (1-10080 minutes) while the Compressive Strength (CS),

    Durability Index (DRI) and Water Resistance Index (WRI) were determined in accordance with

    ASABE standards. Briquette burn rate and thermal efficiency of the stove were determined using

    the standard water boiling test. Data were analysed using ANOVA.

    The MC and BD of GS (10.0 % and 150.0 kg/m 3 ) were higher than those of MCP

    (9.0 % and 134.0 kg/m 3 ). The gum yield of C. populnea was 1.40±0.05 % at 12.60±0.02 % MC.

    There was positive correlation between gum concentration and viscosity (R 2 =0.958). The piston

    press type briquetting machine produced 50.0 mm diameter and 60.0 mm long hollow cylindrical

    briquettes and gave a maximum through-put of 0.6 kg/h. The combustion chamber of the clay-

    lined steel stove accommodated a maximum of 5 briquettes. Minimum gum contents required for

    durable briquette production were 10.0% and 15.0% for GS and MCP respectively. Increase in

    binder concentration enhanced the linear expansion of both Gmelina arborea Sawdust Briquette

    (GSB) and Maize Cob Briquette (MCB) with the increase more pronounced in the MCB than

    GSB. There was significant difference (p0.05) between the DRI values. The strongest and most

    durable briquettes were obtained using fine particle size at a pressure of 1.5 MPa and 25.0% gum

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    content. The burning rate of GSB was 0.800±0.003 kg/h while that of MCB was 1.000±0.018

    kg/h. There was no significant difference (p>0.05) in their burn rate values. However, it took

    more time to boil one litre of water with GSB (22-24 min) than MCB (16-18 min). Maximum

    thermal efficiency of the stove was 38.0 %.

    Cissus populnea gum was suitable for the production of briquettes from Gmelina sawdust

    and maize cob particles. However, Gmelina arborea Sawdust Briquettes were stronger and more

    durable but less efficient in combustion than Maize Cob Briquettes.

    Keywords: Biomass residues, Briquettes, Cissus populnea, Briquette stove.

    Word count: 498

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    To God almighty and Christ Jesus, the Son of the Living God, my Lord and Saviour that has

    made me His ambassador to the nations;

    To my parents, Deacon S.A. Oyedemi and Mrs. R.O. Oyedemi who are the architects of my


    To my darling wife, Dasola Oyedemi and our children: Adetola, Temiloluwa, Iyinoluwa and


    To my brothers and sisters, Sade, Bimbo, Toye and Niyi, the most wonderful people a person

    could ever have;

    To Late Prof. J.O. Oyelese and Mr. Sule Akinteye, who helped a lot to fashion my education.

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    May the Almighty God receive all glory, honour, praise and thanksgiving in that all

    sufficient Name of Jesus for making this work possible. He is faithful and His mercies endure

    forever. He is not only the Author and Finisher of my Faith, but also that of this study. He

    provided the sound health, strength, wisdom, men, money, materials, divine favour and

    everything the work needed for the timely and smooth completion of the study. Without His

    intervention and inspiration, this work would not have been possible. I give Him all adoration

    and worship now and for evermore in the mighty Name of Jesus, Amen.

    I am highly indebted to Prof. A.O.Olorunnisola for his meticulous supervision, advice,

    critique, and his sustained kindness, encouragement, support and the stirring-up to quickly finish

    the work regularly provided by him throughout the period of the study. Despite his very tight

    schedules as the Dean of Postgraduate School, University of Ibadan. He always takes time to

    ensure that this work is completed on time. My sincere and profound appreciation goes to Prof.

    O.A. Odeku for her unwavering support, patience, invaluable guidance and advice,

    understanding and encouragement and particularly her mentoring and her faith in my abilities

    that have brought this work to completion.

    I am greatly indebted to Prof. J.C. Igbeka who started me off on this study before my

    present supervisors took over. My profound appreciation goes to Prof. F.O. Aboaba, who

    inspired me to read Agricultural Engineering at the Postgraduate level, notwithstanding my

    Mechanical Engineering background. He is a father to me and he still takes very keen interest in

    my academic and spiritual progress.

    I sincerely acknowledge the immense contributions of Prof. R.O. Fagbenle of the

    Mechanical Engineering Department. He stimulated my interest in Energy Studies and also

    provided expertise advice and link for current literature I received from Dr. D.A. Fadare, who

    was abroad at the onset of the work. I am very grateful to Dr. Fadare for sending me a copious

    list of current literatures on briquetting.

    Particular thanks to Dr. Yahaya Mijinyawa, the current Head of Agricultural and

    Environmental Engineering department for facilitating the completion of the work. I also wish to

    acknowledge the fatherly concern and encouragement; the timely and useful suggestions of Rev.

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    Prof E.B. Lucas. The immense contributions of: Dr. A. Dare of the Mechanical Engineering

    Department; the encouragement by Prof. A.Y. Sangodoyin and Prof. Ajav of the Agricultural

    and Environmental Engineering Department are highly appreciated.

    My appreciation goes to Engr. (Prince) Bolade Olaniyan of the Mechanical Engineering

    Department, Polytechnic Ibadan, Mr. M.A. Lawson, and Mrs Dupe Ade-Oluwa of the I.I.T.A for

    expert advice on AutoCAD drawing and other computer-related aspects of the work.

    Special thanks to my darling wife, Dasola for her unflinching support and

    encouragement. I appreciate the support and encouragement of all my children throughout the

    period the study lasted – Tola, Gboye, Iyinoluwa, and Abimifoluwa Oyedemi.

    I will forever cherish the encouragement and the support of my pillars of existence –

    Deacon and Mrs. S.A. Oyedemi who had always prayed to God to have one of their sons

    becomes a Ph.D holder in life. I appreciate my blood brothers and sisters – Mrs. Sade Idowu; Mr.

    Toye Oyedemi; Mr Niyi Oyedemi and Mrs. Bimbo Okesiji for their support, prayers and

    encouragement throughout the period the study lasted.

    My gratitude goes to the concerned faculty lecturers, friends and relations too numerous

    to list. Included in the list are Prof. Ayo Oluleye; Prof. B. Alabi; Prof. Ayo Og