(336j) Energy Quality Factor and Exergy Destruction Processes Analysis for a Proposed Polygeneration System

A new polygeneration system was established through combining coal pyrolysis with semicoke combustion, semicoke gasification and a steam Rankine cycle, and then the calculation methodology was developed to calculate the system. The energy and exergy efficiencies of the system are 65.9 % and 75.1 %, respectively; and the standard energy quality factor α^θ values of the involved 17 components and the energy quality factor α of each system stream were obtained. By comparing the differences among the standard energy quality factor α^θ values of the related 17 components, the features of the energy grade of the components at the standard conditions were elucidated. Then the effect of stream¢s composition and temperature on the actual energy quality factor was discussed. Combining the concept of energy quality factor, the processes of exergy destruction in system blocks were visually expressed via a kind of diagram; and the reasons of exergy destruction were tried to be explained from the perspective of energy quality factor.