Experimental study on optimisation of regeneration time of softened water exchanger under salt washing condition

The regeneration time of the softened water exchanger plays a crucial role in the softened water system. An appropriate regeneration time can not only ensure the normal operation of the softened water system, but also effectively save energy. In industrial production, the regeneration time of softened water exchangers is set based on experience and has not been quantified. In this study, the effects of sodium chloride concentration and regeneration rate on resin regeneration were explored by designing experiments in a sodium ion exchange resin tank, and the optimal regeneration scheme was found. The optimum salt washing conditions are: salt washing concentration of 5% and salt washing rate of 5 m/h, which was used in the softened water exchanger. According to the trend of electrical conductivity and hardness changing with time in backwashing, salt washing and positive washing, the regeneration time of the softened water exchanger was determined and adjusted in actual production. Compared with before adjustment, the water production in each production cycle had not changed obviously, but the regeneration time had been shortened by 1200 s, and 2.14 t of water and 0.12 t of salt had been saved, which provides theoretical guidance for the production of softened water.