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The consumption of biomass fuel is increasing worldwide due to concerns over energy shortage of fossil fuels and due to increasing of carbon dioxide emission. Even that burning of biomass fuels releases carbon dioxide, the regrowth of the sustainable managed trees offset that release, which is not possible with fossil fuels. Many African countries depend on agricultural activities -Tanzania is one the African countries, which is located in the equatorial region. It has large source of biomass material.Biomass makes 88% of the primary energy consumtion in Tanzania , So, biomass is used as a solid fuel, the demand of liquid and gaseous fuel has made several researchers convert biomass to liquid and gaseous fuel through relevant processes. By using the Pyrolysis processes that is used to convert solid biomass to liquid or gaseous fuel. And It is the process by which biomass is heated without oxidizing agent. Three main products are obtained as gas, liquid, and solid phases. The gas mainly contains carbon dioxide, carbon monoxide, methane, and hydrogen . The solid part is char, which is made up of fixed carbon and ash. The third and main product is liquid, also known as bio-oil, which contains several compounds. In this study, the formations of compounds which are constituted in bio-oil were studied by using pyrolysis in different temperature, the biomass material used is the coconut shells. Methodology 1-Biomass Preparation The coconut shells were obtained from local farmers of Tanzania. after removing husks and kernels of the coconut. The coconut shells were sun-dried until they became brittle, followed by grinding to less than 0.25 mm to increase surface area yielding bio-oil during pyrolysis. 2-Coconut Shell Characterization 2-1 Determination of Ultimate and Proximate Analysis Important characteristics of biomass materials . The proximate analysis was done to observe the moisture, fixed carbon, and ash content of the biomass material. Ultimate analysis was done to observe the elemental analysis of biomass materials, such as carbon, hydrogen, oxygen, and nitrogen. And The important components of fuels are carbon and hydrogen. 2-2 Determination of Gross Calorific Value The gross calorific value of the biomass material was obtained by using bomb calorimeter model. 2-3 Thermogravimetric Analysis During thermogravimetric analysis, 20 mg of biomass material was put in the crusible and then kept in the thermogravimetric analyzer . The TG was run under nonisothermal conditions and the temperature was raised from room temperature 303 K to 1100 K and the heating medium was nitrogen at a flow rate of 50 mL for min. The heating rate applied was 10 K for min. 3-Analytical Pyrolysis A 1 mg sample of biomass material was kept on the filament and heated at a constant temperature for 2 s. The reaction temperatures applied were 673 K , 773 K, 873 K; the pyrolysis medium was helium. And The gas produced during pyrolysis were analyzed by using Py-GC/MS. Results and Discussion Biomass Characterization Test results of the proximate and ultimate analysis of the coconut shells and higher heating value are shown in Table 1. It has been observed that coconut shells contain high carbon about 50%wt and hydrogen content about 6%wt.The presence of nitrogen and oxygen about 46%wt which reduces the energy content of biomass materials, because these elements do not support combustion. And The higher heating value of coconut shell was about 17 MJ/kg. - Thermogravimetric (TG) Analysis of Biomass the final temperature depends on the type of the biomass material. The final temperature for lignin degradation for coconut shells is about 1000 K. This means that the pyrolysis temperature for any biomass material should be above its final temperature, because at that temperature all volatiles from biomass will be already removed. -Biomass Pyrolysis by Using PY-GC/MS :The three components of biomass depend on both types of biomass and pyrolysis temperature. •The Gas It has been observed that the gas increases as pyrolysis temperature increases as shown in Figure 3 •Alkane The alkane produced during biomass pyrolysis is pentane, the amount which increases with increasing temperature. The alkanes are important compounds in bio-oil production, since it is very combstible. •Acids The acids reduce the pH of the bio-oil produced during pyrolysis. •Nitrogen Compounds In this study, it has been observed that the nitrogen containing compounds decrease by increasing temperature. 4. Conclusion The characterization of coconut shell shows that The reaction temperature during pyrolysis increases the intensity of the pyrolysis products .The coconut shell cannot be a good source of liquid (bio-oil) fuel, since it has a high proportion of acetic acid and nitrogen compounds, also lower pentane, but it contains higher proportion of phenolic compounds. Instead, it can be a good source of gaseous fuel .