Optimization of energy-saving distillation system of absorption heat pump based on intermediate heat exchange

•An absorption heat pumps distillation system based on intermediate heat exchange is proposed.•The optimum operating parameters of the new system are obtained.•The total energy consumption of the distillation columns can be reduced by 38.8%.•The water savings of the new system can be reduced by 42.5%.•The fixed payback period for the renovated project is about 3.0 years.