Efforts to improve the physical and chemical properties of vegetable oils as diesel fuels such as viscosity and calorific value are indispensable with the depletion of fossil oil reserves. Jatropha oil with long chain fatty acids and high degree of unsaturation is mixed with short chain saturated fatty acid coconut oil in various compositions. The mixture was heated and stirred for 30 min at 90 °C. This mixing leads to a decrease in viscosity which allows for the breaking of the bond. The fatty acid molecule structure undergoes transformation that changes the degree of unsaturation and the average length of the carbon chain. Consequently, the kinematic viscosity and flash point of the mixture decreases while its calorific value increases.
1 December 2021 in Case Studies in Thermal Engineering
Protonic ceramic fuel cells (PCFCs) offer direct and efficient conversion of hydrocarbon fuels into electricity. In this study, three internal-reforming (IR)-PCFC/gas turbine (GT) hybrid systems are proposed and analyzed to achieve higher system efficiency. High-quality heat from GT in system 1 and system 2 is supplied to anode and cathode preheaters, respectively, whereas in system 3, the heat is simultaneously split into both preheaters. Effects of air flow rate, fuel utilization factor (Uf), and steam to carbon ratio (S/C) are also investigated. It is found that the best system design can be achieved by effectively utilizing GT exhaust heat for both electrode preheaters, as indicated in system 3. The maximum energy system efficiency obtained among the hybrid systems analyzed in this study is 71% with total exergy destruction of 686.7 kW. When fueled by methane, the hybrid system can achieve energy and exergy efficiencies of 71% and 77%, respectively, with 0.85 Uf. On the other hand, propane-fueled systems can achieve energy and exergy efficiencies of 68% and 75%, respectively. As S/C increases from 2 to 7, system efficiency decreases from 71% to 50%. When system 3 is fueled with butane or propane, system efficiency is only 3% lower than that fueled by methane.
This research was conducted to find out the influence of the use of a catalyst (zeolite) against kinetic rate results of tar pyrolysis of sawdust mahogany. research process undertaken experimentally with temperature 523K and 873K on the heating rate 673 K/hour. pyrolysis is done for 3 hours with wood powder particle size 0,5 – 1 mm. before use activated zeolite in advance by means of heated at a temperature of 400 °c for 1 hour. the results showed the value of kinetic rate tar with zeolites greater than without zeolites , where the value of the kinetic rate equation obtained i.e. 𝑘 = 185,49. 𝑒 −2779/𝑇 (heating rate 673 K/hour without zeolite) and 𝑘 = 93,037. 𝑒 (heating rate 673 K/hour with zeolite). The results of the validation shows the value addition in the calculation of the volume is already approaching the actual value.