Preface

Worldwide many thermal industries are working without tapping the valuable waste heat into a useful form. Electricity is one of the most extensively used commodities in the world. The existing and futuristic power plant configurations and its characteristics suitable to a waste heat recovery (WHR) are discussed in the book. Novel power plant configurations are developed and elaborated from modelling to the optimization through the simulation. Five different power plants configurations, suitable to heat recovery are presented viz. organic Rankine cycle (ORC), organic flash cycle (OFC), Kalina cycle (KC) steam Rankine cycle (SRC) and steam flash cycle (SFC). Out of these power plant layouts, flash cycle (FC) has been recommended because of its adoptability to the heat recovery. The novel flash cycle, which is different from the current geothermal power plant is detailed to augment the heat recovery and power with organic fluid system and steam system. In a power plant, the source temperature may fall below the critical temperature of the fluid or above it. The performance characteristics of these power plants differ with the working fluid and state of heat source, i.e., below or above the critical temperature. Separate performance characteristics and correlations are developed in these two regions for all the selected fluids. The selected working fluids in the heat recovery power plants are R123, R124, R134a, R245fa, R717 and R407C. In FC, the liquid is flashed from high pressure to low pressure at the exit of heat recovery’s economizer. The vapour is separated from the process and used in turbine for power augmentation. However, the handling of additional fluid in boiler increases the pump capacity and heat recovery. Therefore, a drop in thermal efficiency has been observed. FC plants are well justified by comparing the existing power plants with its higher production rate. A case study related to cement factory’s heat recovery has been presented to understand the power plant nature with heat recovery. The cement factory demands 15 MW for its functioning and the case study showed that the WHR is capable of producing the self-generation to meet the load. A lower heat recovery pressure is suggested for maximum power. Second case study is at a 7.7 MW power plant operating under SFC. The theoretical results are validated with a cement factory’s case studies with SRC and SFC. The mathematical simulation has been extended to solve ‘n’ flashers in SFC. Finally, OFC and SFC are recommended in place of ORC and SRC for maximum output.

Organic flash cycle or steam flash cycle are not reported in the available books in the area of power industry. This book companions the undergraduate and post graduate students of mechanical, electrical and similar streams, power plant engineers, practising engineers, research scholars, faculty and plant trainees in the field of power generation. Latest power plant configurations, selection of working fluids to suit the heat recovery temperature and novel flashing cycle in place of organic Rankine cycle and steam Rankine cycle are the key features of this book.