Energy savings through the appropriate implementation of combined heat and power (cogeneration) scheme

Combined Heat and Power (CHP) scheme, also known as cogeneration is widely accepted as a highly efficient energy saving measure, particularly in medium to large scale chemical process plants. To date, CHP application is well established in, the developed countries. The advantage of a CHP scheme for a chemical plant is two-fold: (i) to drastically cut down on the electricity bill from on-site power generation (ii) to save on fuel bills through recovery of the quality waste heat from power generation for process heating. In order to be effective, a CHP scheme must be placed at the right temperature level in the context of the overall process. Failure to do so might render a CHP venture worthless. This paper discusses the procedure for an effective implementation of a CHP scheme. An. ethylbenzene process is used as a case study. A key visualisation tool known as the grand composite curves is used to provide an overall picture of the process heat source and heat sink profiles. The grand composite curves, which is generated based on the first principles of Pinch Analysis enables the CHP scheme to be optimally placed within the overall process scenario.