Issue Section:
In this study, an internal combustion engine is experimentally analyzed under 100 Nm engine load using biodiesel and diesel fuels. The analyses of energy, exergy and environment are also applied to the internal combustion engine without after treatment system (Engine-Out) and with silicon carbide-based diesel particle filter (SiC-DPF) after treatment system. The impact of the utilization of SiC-DPF on the exhaust emissions and energy, exergy, environmental analyses results are examined. It is determined that (1) the work rate of diesel-fueled engine is higher than the biodiesel-fueled engine. (2) When energy and exergy losses are taken into consideration, the use of SiC-DPF has a positive effect on the emissions of the biodiesel-fueled engine, but it does not have the same effect for the diesel-fueled engine. (3) The biodiesel-fueled engine has higher energy and exergy efficiencies than diesel-fueled engine with and without after treatment systems. (4) In terms of exergy destruction, the results of the diesel-fueled engine have the maximum value with the use of SiC-DPF after treatment system, while the results of the biodiesel-fueled engine have the minimum value with the use of SiC-DPF. This reveals the effectiveness of the use of SiC-DPF after treatment system. (5) The emission rate of CO2 is obtained as maximum for the biodiesel-fueled engine. Also, the minimum CO2 emission rate is determined for the diesel-fueled engine without after treatment system. The use of SiC-DPF contributes to a reduction in CO2 emission for the biodiesel fuel, while it causes an increase for the diesel fuel. (6) The entropy generation rate of the biodiesel-fueled engine is lower than the diesel-fueled engine with and without after treatment options. This study could help future studies on the choice of fuels and utilization of after treatment systems in the internal combustion engines in terms of better environment.
In this study, energy, environment and enviroeconomic analyses are applied to the turbofan engine used in aviation industry. The CO2 emissions of the turbofan engine are calculated and cost of the CO2 emissions for a daily period are evaluated. The energy efficiencies of the overall turbofan engine system, high pressure turbine, low pressure turbine and the combustion chamber are found as 19.7%, 26.2%, 29.2% and 90%, respectively. The CO2 emissions releasing in a day are calculated as 358.9 tonCO2/day, while the CO2 emissions price in a day are calculated as 5742.52 US$/day for the turbofan engine. Also, 3.35 kg carbon dioxide is released into the air as a result of 1 kg of kerosene burning. Environmental and the enviroeconomic results of this study can be useful for developing environmentally sustainable turbofan engines as well as for researches and designers in aviation industry.
Keywords
atmospheric emissions; CO2; energy efficiency; enviroeconomic analysis; environmental analysis; gas turbine
In this study, the conventional and advanced exergy analyses are performed to the cogeneration system (COGEN) that consists of gas turbine unit and spray dryers in ceramic factory under five different environment conditions for the optimization. According to exergy analysis, the maximum exergy efficiency of the COGEN is found as 29.850% at 30 °C environment temperature, while the maximum exergy destruction rate is calculated as 17810.61 kW at 30 °C environment temperature. According to advanced exergy analysis, combustion chamber (CC) may not be the only component to be focused on for exergy destruction. Because, the exergy destruction rate can be caused by its own internal reasons (endogenous) as well as other components (exogenous). In other words, the relationship between components can be revealed. Chemical reactions occurring in CC, wall tile dryer (WD) and ground tile dryer (GD) cause an increase in endogenous exergy destruction rate of the COGEN system. Due to the improvement potential increase in components, the exergy efficiency of the whole system (COGEN) increases to between 45% and 47% with an increase of approximately between 15% and 17% for five different dead temperatures. Also, the unavoidable exergy destruction rates of the CC and air compressor (AC) are much higher than their avoidable exergy destruction rates. In particular, the avoidable exergy destruction of the WD and GD has been shown to have a significant effect on other components.