Improving the efficiency of heat recovery circuits of cogeneration plants with combustion of water-fuel emulsions

Abstract

When using modern highly efficient internal combustion engines with lowered potential of exhaust heat the heat recovery systems receive increasing attention. The efficiency of combustion exhaust heat recovery at the low potential level can be enhanced by deep cooling the combustion products below a dew point temperature, which is practically the only possibility for reducing the temperature of boiler exhaust gas, while ensuring the reliability, environmental friendliness and economy of power plant. The aim of research is to investigate the influence of multiplicity of circulation and temperature difference at the exit of exhaust gas boiler heating surfaces, which values are varying as 20, 15, 10?C, on exhaust gas boiler characteristics. The calculations were performed to compare the constructive and thermal characteristics of the various waste heat recovery circuits and exhaust gas boiler of ship power plant. Their results showed that due to application of condensing heating surfaces in exhaust gas boiler the total heat capacity and steam capacity of exhaust gas boiler increases. The increase of exhaust gas boiler heat capacity is proportional to the growth of its overall dimensions. A direct-flow design of the boiler provides a significant increase in heat efficiency and decrease in dimensions. In addition, a direct-flow boiler circuit does not need steam separator, circulation pump, the capital cost of which is about half (or even more) of heating surface cost.

Monitoring the efficiency of cooling air at the inlet of gas engine in integrated energy system

“…There are a lot of waste heat recovery technologies developed to enhance a fuel efficiency of combustion engines: by utilizing the exhaust heat [11,12] and cooling engine cyclic air (intake and scavenge air) in electrically driven vapour-compression refrigeration machines [13,14] and waste heat recovery chillers [15,16]. The most widespread ACh's enable cooling air to the temperature of about 15 ºС with a high coefficient of performance: COP = 0.7-0.8 [17,18].…”

Gas turbine intake air hybrid cooling systems and their rational designing

“…The technical innovations in waste heat recovery [15,16] including transport application [17,18] might be successfully applied in TIAC: two-stage intake air cooling [10], deep exhaust heat utilization [19,20]. The heat potential for converting in refrigeration can be increased due to low-temperature condensation [21,22].…”

Alternative variable refrigerant flow (VRF) air conditioning systems with rational distribution of thermal load

“…Some innovative technics in engine intake air cooling [21,22] and waste heat conversion might be implemented in ACS. The heat potential converted in refrigeration can be increased by deep heat utilization [23][24][25] and application of lowtemperature condensing surface [26,27]. The absorption lithium-bromide chillers (ACh) are the most widely used and provide cooling air to about 15 ºС with a high coefficient of performance (COP = 0.7-0.8) [28].…”