Performance Improvement of a Diesel Engine Power Plant with Optimal Utilization of Waste Heat Udalamattha Gamage Kithsiri Derating Vs Temperature and Relative Humidity 14 12 10 8 6 Derating /% 4 2 0 100 80 80 90 60 100 110 40 120 20 130 0 Relative Humidity/% Temperature/oF Master of Science Thesis KTH School of Industrial Engineering and Management Energy Technology EGI-2016-018MSC EKV1130 Division of Heat & Power SE-100 44 STOCKHOLM Master of Science Thesis EGI-2016-018MSC EKV1130 Performance Improvement of a Diesel Engine Power Plant with Optimal Utilization of Waste Heat U. Gamage Kithsiri Approved Examiner Supervisor (KTH) 2016-05-20 Miroslav Petrov - KTH/ITM/EGI Miroslav Petrov Collaboration Supervisors (OUSL) Open University of Sri Lanka Dr. N. S. Senanayake Ruchira Abeyweera Abstract Due to temperature and humidity deviations from the standard ISO conditions in real operational conditions in the tropical countries the performance of diesel engines used for power generation drops significantly. One of the reasons for dropping the engine performance is due to engine de-rating, hence increasing the specific fuel consumption. The present study was undertaken to develop a model for predicting whether the prevailing site conditions cause de-rating at a specific power plant in Sri Lanka. The model was developed with the aid of recorded information in previous studies and was validated with site conditions revenant to a selected location in Sri Lanka. In the study a set of equations was developed corresponding to different temperatures to predict engine de-rating as a function of relative air humidity. To achieve the required standard conditions in view of avoiding any de-rating of the engines, the charge air temperature needed to be reduced. For this purpose an absorption chiller system was proposed and designed to be operated with the waste heat recovery from the power plant. It proved that implementation of such a system is technically and economically feasible with a simple payback period of three and a half years on the capital invested. This derived model was applied to actual operational data of the selected power plant and finally it was found a derated power of 417 kW could be fully recovered by conditioning the temperature and humidity of charge air to obtain the ISO conditions, giving a benefit equivalent fuel savings of 2233 kg/day. CONTENTS 1 INTRODUCTION .............................................................................................1 1.1 Background .......................................................................................................................... 1 1.2 Problem Identification … .................................................................................................. 2 1.3 Objectives … ......................................................................................................................... 2 2 METHODOLOGY ............................................................................................4 3 DIESEL ENGINE AND AUXILARY SYSTEMS ......................................................5 3.1 Diesel engine and working prnciples ............................................................................ 5 3.1.1 Thermodynamic cycle ...................................................................................................... 5 3.1.2 Heat supplied to diesel engine ........................................................................................ 5 3.1.3 Expected outcomes from diesel engine .......................................................................... 6 3.2 Engine auxilary systems … ................................................................................................ 6 3.2.1 Cooling water system ...................................................................................................... 6 3.2.2 Lube oil system ................................................................................................................ 8 3.2.3 Fuel oil system ................................................................................................................. 9 3.2.4 Fuel oil system parameter variation ................................................................................ 9 3.2.5 Turbo charging system .................................................................................................. 10 3.3 Specfic fuel consumption… ............................................................................................ 14 3.4 Engine de-ration …............................................................................................................ 16 3.4.1 Ambient temprature ..................................................................................................... 16 3.4.2 Humidity ........................................................................................................................ 16 3.4.3 Altitude .......................................................................................................................... 17 4 WASTE HEAT RECOVERY METHODS ............................................................................... 18 4.1 Waste heat ......................................................................................................................... 18 4.2 Factors affecting waste heat recovery ....................................................................... 18 4.3 Waste heat recovery technology ................................................................................. 18 4.4 Vapour absorption Chiller systems ............................................................................ 21 4.5 Waste heat sources of diesel engines ....................................................................... 22 5 MODEL DEVELOPMENT ....................................................................................................... 23 5.1 Prioritization of parameters .......................................................................................... 23 5.2 Model for engine de-rating … ....................................................................................... 23 -i- 5.3 Summary of de-rating model ........................................................................................ 28 5.3.1 Specific de-rating calculation at site conditions ............................................................ 28 5.3.2 Flow chart of the performance evaluation.................................................................... 28 6 MODEL TESTING WITH ACTUAL DATA .......................................................................... 30 6.1 Uthuru Janani Power Sation (UJPS) ............................................................................. 30 6.2 Data collection … ............................................................................................................... 30 6.2.1 Instrument details ......................................................................................................... 30 6.3 Engine de-rating evaluation … ....................................................................................... 31 6.3.1 De-rating due to ambient temperature effect .............................................................. 31 6.3.2 De-rating due to relative humidity effect ...................................................................... 33 6.3.3 Total engine performance de-rating ............................................................................. 35 6.4 Evaluating the SFC and potential fuel savings … ...................................................... 37 7 EXHAUST ENERGY AVAILABLE AND COOLING LOAD ............................................... 39 7.1 Calculating the Intake Air mass flow rate .................................................................. 39 7.2 Air intake flow at 30% RH & 25oC ambient temperature ...................................... 40 7.3 Cooling load required to condition the air humidity .............................................. 40 7.4 Cooling load required to reduce the charge air temperature ............................. 42 7.5 Waste Heat Energy available in the engine exhaust gases ................................... 43 7.6 Waste Heat available in the engine HT cooling water circuit .............................. 44 7.7 Catering the cooling load by a vapor absorption chiller ....................................... 45 7.8 Investment Cost and Payback Period calculation ................................................... 47 8 CONCLUSION AND DISCUSSION ...................................................................................... 49 References ........................................................................................................................................ 51 APPENDIX A ........................................................................................................................................... 53 APPENDIX B ........................................................................................................................................... 55 APPENDIX C ........................................................................................................................................... 57 APPENDIX D ........................................................................................................................................... 60 APPENDIX E ............................................................................................................................................ 62 APPENDIX