A thesis submitted in partial fulfillment of the requirements for the degree of Master in Engineering, School of Environment, Resources and Development

Thesis (M.Eng.) - Asian Institute of Technology, 1988

A study of a cogeneration system in Shakarganj Mills Ltd ( SML), Jhang (near Faislabad) was performed . Energy and exergy analysis of the components of the cogeneration system was carried out. The cogeneration system comprised three boilers having capacities of 80 t/h, 2 * 40 t/h respectively (the third one being the standby), three turbogenerators of capacities 2 * 2 MW a nd 3.5 MW ( standby) respectively . Turbogenerators 1 and 2 are operating at same output . Five milling turbines of capacity 4 * 373 kW a nd 1 * 596 kW, one unigator and one cutter turbine of capacities 1040 kW and 373 kW respectively. The milling turbine No 2, 3 & 4 are operating at same output. The analysis was don separately for 80 t/h and 40 t/h boilers. For 80 t/h boiler the best efficiency was found to be 60. 1 % and worst efficiency was 58. 3 % {u2022} For 40 t/h boiler the best efficiency was found to 59.8 % and worst efficiency was 58.4 % The best and worst efficiencies for other equipment have also been determined. The technical and economic feasibility study of bagasse drier using flue gas from the boiler was also carried out. The cogeneration system was modelled using actual data collected and n ew data generated for the bagasse dryer. Computer programmes were made to simulate the cogeneration system, taking into account the capacity limitations of the components of the system. Bas e d on the first and second law analysis a nd on the model developed , energy conservation measures were suggested to improve the efficiency of the cogeneration system. Other major energy conservation measures suggested. are also given such as suggestions for Energy Management, reduction of excess air supplied to the boilers, and operating turbo generators , mills , unigator and cutter turbines close to their rated characteristics.