Analysis of gas turbine integrated cogeneration plant: Process integration approach

Cogeneration is defined as generation of two forms of energy viz. heat and work using single primary fuel. Cogeneration or combined heat and power (CHP) is important in improving energy efficiency of the overall plant and in reducing environmental pollution. A methodology, based on pinch analysis, is proposed in this paper to integrate gas turbine and regenerator with a process plant to minimize fuel consumption. Thermodynamic analysis of gas turbine integrated CHP plant is presented on gas turbine pressure ratio versus power to heat ratio diagram. On this novel diagram, limits of integration are identified and various regions of integration are represented. Additionally, contour plots of energy utilization factors and fuel energy saving ratios are represented on this diagram for optimal integration of gas turbine with a process plant. It is interesting to note that though the contour plots of energy utilization factors and fuel energy saving ratios differ significantly, loci of the maximal energy utilization factor and the maximal fuel energy saving ratio are identical. Optimum sizing of gas turbine integrated cogeneration plant for grassroots design and retrofitting are performed based on these diagrams.