Graphical cogeneration analysis for site utility systems

It is necessary to systematically evaluate site-wide power and heat generation, distribution, and utilization. A new graphical approach based on a Site Grand Composite Curve (SGCC) to targeting cogeneration in site utility systems is proposed to extend Pinch Analysis. The SGCC presents quantitative and visual process targets of heating and cooling requirements, site utility system targets for system steam generation and potential shaft power by steam expansion and condensation. Process indirect heat recovery by intermediate steam levels that can reduce fuel consumption is analyzed readily in the approach. The steam cascade in the SGCC clarifies the Total Site Pinch and site targets of utility very high pressure steam demand and site steam saving. This graphical analysis presents greater clarity for the quantitative interaction between processes and utility system targets than previous approaches. The influence of process variation and steam mains selection on cogeneration improvements is explored much clearer in this straightforward method.