Abstract
In this paper, the energy-chemical systems incorporating waste treatment are analyzed using emergy analysis. Firstly, the system boundary with different types of waste is determined. Then the deficiency of traditional emergy-based indicator, environmental loading ratio (ELR), is discussed, and an alternative indictor ELRW is given. In addition, to assess the impact of waste, the parameters for waste(W) and impact amplification coefficient (?) are proposed for inclusion in traditional indicators. Finally, methanol synthesis (MEOH), Integrated Gasification Combined Cycle (IGCC) and poly-generation (PG) systems are analyzed by the modified indicators. The results show that the new indicators are reasonable to explain the environmental stress; IGCC has less economic competitiveness; MEOH gives the most pressures on the environment; the sustainability of PG is higher than MEOH and IGCC as well as the maximum tolerable value of waste negative effect reaches 4.33.
