Assessing the potential environmental impact of fuel using exergy-cases of wheat straw and coal

The potential impact of a fuel on the environment mainly comes from the emissions of the fuel. This study proposes an idea of assessing the potential environmental impact of fuel by demonstrating the exergy of potential emissions of CO2, NO2, SO2 and ash from the fuel. This method was then used to assess the potential environmental impacts of four wheat straws and three coals. The results show that the potential environmental impacts of wheat straws vary in the range of 736.89-813.71 kJ/kg, and they are contributed by CO2 (79.18-89.77%), ash (7.08-14.46%), NO2 (1.59-4.98%) and SO2 (0.91-1.39%). However, the potential environmental impacts of coals vary in the range of 1324.98-1437.47 kJ/kg, and they are determined by CO2 (66.33-71.12%), ash (13.08-22.23%), SO2 (5.24-11.77%) and NO2 (2.53-6.20%). The wheat straws show lower potential environmental impacts than the coals, they are, therefore, more friendly to the environment.