Department of Chemical and Mining Engineeering

Permanent URI for this collection

https://repository.udsm.ac.tz/handle/123456789/2

Browse

Browsing Department of Chemical and Mining Engineeering by Subject "Biodiesel"

Now showing 1 - 7 of 7
  • Thumbnail Image
    Item
    Experimental Investigations of Fuel Properties of Biodiesel Derived from Tylosema Esculentum Kernel Oil
    (Taylor & Francis, 2013) Gandure, Jerekias; Ketlogetswe, Clever; Temu, Abraham K.
    The alternative fuels debate continues to attract the attention of researchers and scientists globally. This paper reports experimental results on selected properties of biodiesel derived from Tylosema Esculentum kernel oil and compares them with similar properties of petroleum diesel to assess its suitability for use as fuel in diesel engines. Results indicate an ester content of 90% for tylosema biodiesel fuel, while its viscosity profile meets requirements of American standards for biodiesel fuel (ASTM D 6751-02). The flash point and cold flow properties of tylosema biodiesel were found to be typical of a biodiesel fuel, while its acidity is within range of both American and European standards by 72.5%, and 56% respectively. It was also observed that biodiesel engine performance is marginally better than that of petroleum diesel, with lower concentrations of hydrocarbon emissions. Levels of carbon dioxide and carbon monoxide (CO) are largely comparable to those of petroleum diesel.
  • Thumbnail Image
    Item
    High Free Fatty Acid (FFA) Feedstock Pre-Treatment Method for Biodiesel Production
    (Trans Tech Publications, Switzerland, 2011) Kombe, Godlisten G.; Temu, Abraham K.; Rajabu, Hassan; Mrema, Godwill D.
    Biodiesel is an alternative fuel for engine and other appliances that is obtained by transesterifying vegetable oils or other materials largely comprised of triacylglycerols with monohydric alcohols to give the corresponding mono-alkyl esters. The quality of feedstocks for the biodiesel production dictates the method of its production and quality. Based on the initial amount of minor components in feedstocks, a process comparison of acid pre-treatment and caustic pretreatment of feedstock for alkali transesterification was done. Acid pre-treatment was carried out with 0.60 w/w methanol-to-oil ratios in the presence of 2% w/w H 2 SO 4 as an acid catalyst in 2 h reaction at 60 °C. In caustic pretreatment process, the same amount of oil was neutralized with the required amount of sodium hydroxide based on the initial amount of free fatty acid and gums in the oil. The acid pretreatment process gives a 4% loss in feedstock compared to 20% from the neutralization process. The yields 96% and 94% of biodiesel from acid pretreated and caustic pretreatment feedstock were obtained respectively. The oxidation stabilities of biodiesel from acid pretreatment and neutralized feedstock were 1.12h and 3h respectively. The biodiesel from acid pretreatment oil could not pass the ASTM standard.
  • Thumbnail Image
    Item
    Investigating Schiziophyton Rautanenii Biodiesel as Fuel for the Diesel Engine
    (2014) Gandure, Jerekias; Ketlogetswe, Clever; Temu, Abraham K.
    The search for plant kernel oils for use as potential substrates for production of biodiesel continues to draw global attention. In the current paper, the performance and emission characteristics of biodiesel derived fromschiziophyton rautaneniikernel oil were investigated in a diesel engine. The parameters investigated are brake thermal efficiency, engine torque, brake power, specific fuel consumption, hydrocarbons, carbon dioxide, carbon monoxide, oxygen and soot production. The results indicate that Schiziophyton rautanenii biodiesel used in this study was comparable to petroleum diesel in terms of performance and emission characteristics, and is recommended for use in diesel engines.
  • Thumbnail Image
    Item
    Low Temperature Glycerolysis as a High FFA Pre-Treatment Method for Biodiesel Production
    (Scientific Research, 2013) Kombe, Godlisten G.; Temu, Abraham K.; Rajabu, Hassan M.; Mrema, Godwill D.; Lee, Keat Teong
    A novel low temperature glycerolysis process for lowering free fatty acid (FFA) in crude jatropha oil for alkali catalyzed transesterification has been developed. The response surface methodology (RSM) based on central composite design was used to model and optimize the glycerolysis efficiency under three reaction variables namely; reaction time, temperature and glycerol to oil mass ratio. The optimum conditions for highest glycerolysis efficiency of 98.67% were found to be temperature of 65℃, reaction time of 73 minutes and 2.24 g/g glycerol to oil mass ratio. These conditions lower the high free fatty acid of crude jatropha oil from 4.54% to 0.0654% which is below 3% recommended for alkali catalyzed transesterification. The pre-treated crude jatropha oil was then transesterified by using homogeneous base transesterification resulting to a conversion of 97.87%. The fuel properties of jatropha biodiesel obtained were found to be comparable to those of ASTM D6751 and EN 14214 standards. The process can also utilize the crude glycerol from the transesterification reaction, hence lowering the cost of biodiesel. The glycerolysis is easier implemented than acid esterification thereby avoiding the need for neutralization and alcohol removal step.
  • Thumbnail Image
    Item
    Optimization of Biodiesel Production from Jatropha Oil
    (Trans Tech Publications, Switzerland, 2010) Apita, Aldo Okullo; Temu, Abraham K.; Ntalikwa, J.W.; Ogwok, P.
    The most important factors that influence biodiesel production are temperature, molar ratio, catalyst amount, time and degree of agitation. This study investigated the effects of temperature, molar ratio and degree of agitation and their interactions on the yield and purity of biodiesel produced from Jatropha oil. Factorial design and response surface methodology (RSM) were used to predict yield and purity of biodiesel as functions of the three variables. Interactions of all the factors were found to be significant on both yield and purity responses. Temperature and molar ratio main effects were found to be significant on the yield whereas only temperature main effect was significant on the purity of the biodiesel. The optimum conditions of operations were; temperature of 54 o C, molar ratio of methanol to oil of 6:1 and stirring speed of 660 rpm. Using these conditions, biodiesel yield of 95% (wt) was obtained with a purity of 97%. This model can be used to predict the yield and purity of biodiesel from jatropha oil within the ranges of temperature (30 – 60C), stirring rate (300 -900 rpm), and molar ratio (3 – 9 mol/mol) studied.
  • Thumbnail Image
    Item
    Performance and Emission Characteristics of Tylosema Esculentum Biodiesel in a Diesel Engine: An Experimental Investigation
    (David Publishing, 2014) Gandure, Jerekias; Ketlogetswe, Clever; Temu, Abraham K.
    Biodiesel derived from indigenous feed stocks such as Tylosema esculentum kernel oil is deemed a feasible alternative to petroleum diesel for the diesel engine. This paper presents results of investigation of performance and emissions characteristics of diesel engine using Tylosema biodiesel. In this investigation, Tylosema biodiesel was prepared, analyzed and compared with the performance of petroleum diesel fuel using a single cylinder compression ignition diesel engine. The specific fuel consumption, engine torque, engine brake power, hydrocarbons, carbon monoxide and carbon dioxide were analyzed. The tests showed a decrease in engine brake power and torque with increase in engine load, while specific fuel consumption showed an increasing trend with maximum variation of 33% between the two fuels at engine load of 90%. Emission levels of hydrocarbons, carbon monoxide and carbon dioxide showed an increasing trend with increase in load for both fuels. Tylosema biodiesel produced significantly lower concentrations of hydrocarbons than petroleum diesel, while levels of carbon dioxide and carbon monoxide were largely comparable to those of petroleum diesel. Soot production from combustion of Tylosema biodiesel was found to be approximately 98% lower than that from combustion of petroleum biodiesel, demonstrating insignificant contribution to environmental pollution
  • Thumbnail Image
    Item
    Physico-Chemical Properties of Biodiesel from Jatropha and Castor Oils
    (International Journal of Scientific and Engineering Research, 2011-03-11) Apita, Aldo Okullo; Temu, Abraham K.; Ogwok, P.; Ntalikwa, J. W.
    Biodiesel is becoming prominent among the alternatives to conventional petro-diesel due to economic, environmental and social factors. The quality of biodiesel is influenced by the nature of feedstock and the production processes employed. High amounts of free fatty acids (FFA) in the feedstock are known to be detrimental to the quality of biodiesel. In addition, oils with compounds containing hydroxyl groups possess high viscosity due to hydrogen bonding. American Standards and Testing Materials, (ASTM D 6751) recommends FFA content of not more than 0.5% in biodiesel and a viscosity of less than 6 mm2/s. The physico-chemical properties of jatropha and castor oils were assessed for their potential in biodiesel. The properties of jatropha and castor oils were compared with those of palm from literature while that of biodiesel were compared with petro-diesel, ASTM and European Standards (EN14214). Results showed that high amounts of FFA in oils produced low quality biodiesel while neutralized oils with low amounts of FFA produced high quality biodiesel. The quality of biodiesel from jatropha and castor oils was improved greatly by neutralising the crude oil