Exergy analysis for recycling alkali from the wastewater of textile mercerisation by mechanical vapour recompression plants

摘要

An exergy analysis model of the MVR evaporation system for recycling alkali from textile mercerisation is established. Calculation results indicate that the total exergy efficiency of the system is 4.8%. The main loss of exergy is from the compressor and evaporator/condenser which take 68% of the total amount. More attention and emphasis should be put to reducing the irreversible loss of them. The experimental and theoretical results show that the exergy efficiency has the peak with the temperature difference of heat transfer in evaporator/ condenser increasing, and the exergy efficiency reaches the peak at ∆t = 6℃. The exergy efficiency increases slightly with the evaporating temperature, and the impact is relatively small compared to temperature difference. And a smaller concentration of distillate is suggested within the requirements of manufacturing process for getting higher exergy efficiency.