Second law analysis of propane and hydrogen fuels combustion

摘要

For the past few years, interest in clean and natural energy sources has increased dramatically. Because of the need for the elimination of air and water pollution and need for obtaining energy cheaper, alternative as well as renewable energy sources are given attention. Hydrogen is such an alternative energy source. The present paper evaluates the reversible work output of hydrogen in comparison to a hydrocarbon fuel (propane) with particular emphasis given to the type of the combustion process, isothermal or adiabatic. The second law of thermodynamics with the aid of first law represents the results of entropy generation, reversible work output, and exergy destruction of isothermal and adiabatic combustion processes of propane and hydrogen fuels. Results based on per kg fuel consumption favor the use of hydrogen over propane and the results based on per kmol fuel consumption favor the use of propane over hydrogen in terms of reversible work output and regardless of the type of the combustion process, adiabatic or isothermal. However, the cost analysis makes the hydrogen use prohibitive over propane costing about 16 to 23 times more compared to the latter.