Browsing by Author "Katima, Jamidu H. Y"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Carbon Footprints of Production and Use of Liquid Biofuels in Tanzania
    (2015) Eshton, Bilha; Katima, Jamidu H. Y
    Tanzania being a prospective producer and exporter of liquid biofuels, information on local contribution of this sector to the environmental burden of the country is highly required in order to ensure sustainable liquid biofuels. Therefore, this paper evaluates a life cycle carbon footprint (or greenhouse (GHG) gas emissions) of liquid biofuels (biodiesel produced from jatropha oil and bioethanol produced from sugarcane molasses as alternative to fossil fuels in Tanzania. The functional unit (FU) of the study is defined as 1 Giga Joule (GJ) of output energy when a biofuel is combusted in the engine. The study found a positive GHG emissions related to biofuels. A carbon footprint (in CO2 equivalents) of jatropha biodiesel is 23.9 kg FU−1 while that of molasses bioethanol is 17.4 kg FU−1. Biodiesel combustion found to be a major contributor to carbon footprint by 41% which is attributed to methanol used during transesterification of jatropha oil followed by the use of chemical fertilizers (31%). Sugarcane production phase on the other hand found to be the highest contributor to carbon footprint of molasses bioethanol accounting for more than 80%. This is due to the use of diesel fuel, chemical fertilizers and burning of sugarcane prior to harvesting. Sensitivity analysis indicates that higher market prices of molasses increases carbon footprint of bioethanol same as higher market price of biodiesel. For the same energy output of 1 GJ, molasses bioethanol observed to have lower carbon footprint than jatropha biodiesel by 27.2%. Both biofuels observed to save GHG emissions by >70% when used as fossil fuel replacement. The study recommends further research on socio-economic implication of large scale biofuel production; impact of land use change and land use competition and sustainability of biofuels to be carried out in near future.
  • Thumbnail Image
    Item
    Greenhouse Gas Emissions and Energy Balances of Jatropha Biodiesel as an Alternative Fuel in Tanzania
    (Elsevier, 2013) Eshton, Bilha; Katima, Jamidu H. Y; Kituyi, Evans
    This paper evaluates GHG emissions and energy balances (i.e. net energy value (NEV), net renewable energy value (NREV) and net energy ratio (NER)) of jatropha biodiesel as an alternative fuel in Tanzania by using life cycle assessment (LCA) approach. The functional unit (FU) was defined as 1 tonne (t) of combusted jatropha biodiesel. The findings of the study prove wrong the notion that biofuels are carbon neutral, thus can mitigate climate change. A net GHG equivalent emission of about 848 kg t−1 was observed. The processes which account significantly to GHG emissions are the end use of biodiesel (about 82%) followed by farming of jatropha for about 13%. Sensitivity analysis indicates that replacing diesel with biodiesel in irrigation of jatropha farms decreases the net GHG emissions by 7.7% while avoiding irrigation may reduce net GHG emissions by 12%. About 22.0 GJ of energy is consumed to produce 1 t of biodiesel. Biodiesel conversion found to be a major energy consuming process (about 64.7%) followed by jatropha farming for about 30.4% of total energy. The NEV is 19.2 GJ t−1, indicating significant energy gain of jatropha biodiesel. The NREV is 23.1 GJ t−1 while NER is 2.3; the two values indicate that large amount of fossil energy is used to produce biodiesel. The results of the study are meant to inform stakeholders and policy makers in the bioenergy sector.
  • Thumbnail Image
    Item
    Modifying Plant Oils for Use as Fuel in Rural Contexts Tanzania: Techno-Economic Analysis
    (2014) Mlay, Happiness; Katima, Jamidu H. Y; Minja, Rwaichi J. A.
    Techno-economic analysis of a small-scale Modified Plant Oil (MPO) production plant that has an annual production capacity of 15,072,741 kg of MPO (batch process) was carried out to estimate the capital and operating costs of a plant. The analysis was done by using a computer model that was designed and simulated with an aid of SuperPro Designer (Version 4.32) software. The specified feedstock was crude Jatropha oil (JO) and the main product was MPO. The major processes involved were degumming, neutralisation and blending. Degumming involved the removal of gums or phospholipids, and two methods were used: water degumming and acid degumming, whereas blending involved mixing of degummed or purified JO with natural gas condensate (NGC) modifier to lower the viscosity of JO. From techno-economic analysis of the process, it was found that the total capital investment of a plant was about US $ 10,222,000 and the predicted unit production cost of MPO was US $ 1.315/kg at a value of US $ 1.0/kg of JO. The economic feasibility of MPO production was found to be highly influenced by the price of feedstock, which contributed about 95% of the total annual production cost. The relationship between plant throughput and unit cost of producing MPO showed that unit production cost was very sensitive to production rate at low annual throughputs. The MPO cost showed a direct linear relationship with the cost of JO, with a change of US $ 0.50/kg of MPO in MPO cost in every change of US $ 0.50/kg of JO in JO price. The process technology simulated was found to be economically viable and can be implemented in rural setting, taking into consideration Tanzania’s rural situation.
  • Thumbnail Image
    Item
    P366: Alternatives to the Biomedical Waste Incineration in the Treatment and Waste Sorting System in the Chain
    (BioMed Central, 2013) Abdoulaye, F.; Elisante, Emrode; Mwinuka, T.; Katima, Jamidu H. Y; Emmanuel, J.
    Within the framework of the International Project UNDP / GEF HCW, which was launched in 2008, the College of Engineering (COET) at the University of Dar es Salaam has developed an affordable technology that is respectful of environment and is based on the concepts of state-of the art autoclave waste treatment systems used in industrialized countries. This equipment without incineration technology has been designed, manufactured and tested at COET through the collaboration of students, teachers, support staff and experts from UNDP / GEF. It is ideal for medium-sized county hospitals of about 100 beds.
  • Thumbnail Image
    Item
    Plant Oil/Fuse Oil Blends as Alternative Fuels in Low-and Medium Speed Diesel Engines
    (2015-04) Mlay, Happiness; Katima, Jamidu H. Y; Minja, Rwaichi J. A.
    Fuel blending is one of the methods of lowering plant oil’s viscosity, which is the major parameter that leads to serious problems on diesel engine performance in terms of operation and durability. A study was carried out on fuel properties of Jatropha (JO) and Croton (CROT) seed oils blended with a distillery by-product, fusel oil (FO) (modifier) of between 20% and 50% (v/v) at room temperature (30 ± 3˚C). The effect of FO composition in the resulting blend on the kinematic viscosity and fuel combustion properties of the blends was analysed. The results were compared to the properties of crude plant oils (POs) and diesel fuel (grade-4D) specifications. The blends were found to be compatible over a wide range of compositions and exhibited much lower viscosity and better combustion properties than crude plant oil (PO) samples. The optimum proportions for a blend’s viscosity to meet the specifications for diesel fuel (grade 4-D) were found to depend on the modifier characteristics; and that 20% (v/v) FO was enough to produce the desired liquid biofuel blend. The characteristics of blends presented in this work matches well with the characteristics of fuels for low- and medium-speed diesel engines. This implies that the PO/FO blends can be used as alternative fuels in low- and medium speed diesel engines.
  • Thumbnail Image
    Item
    Steam Pretreatment of Pine (Pinus Patula) Wood Residue for the Production of Reducing Sugars
    (2011) Chacha, Nyangi; Toven, Kai; Mtui, Godliving; Katima, Jamidu H. Y; Mrema, Godwill
    The study explores the production of reducing sugars from Pinus patula wood residual chips based on steam pretreatment technology. The severity of the steam pretreatment was altered by using two levels of temperature and time and three levels of sulphur dioxide impregnation. The results show that the efficiency of enzymatic hydrolysis depends on the severity of steam pretreatment. On a given cellulose content, the reducing sugar yield increased from 29% (15.6 g/L) under the mildest steam pretreatment conditions (180 °C, 1.5% SO2) to 91% (42.3 g/L) under the most severe steam pretreatment conditions (225 °C, 3% SO2). In all cases, the enzymatic hydrolysis yield is dependent on enzyme accessibility to the cellulose chains, as the steam pretreatment severity strongly affects biomass fragmentation.