In the beginning the fresh salt bisulfite qualified by evaluation is included the prep work still, under area temperature, typical stress problem, be made right into the liquid service of 35wt% with distilled water.
Send out 2857Kg (concentration: 35wt%) of the ready sodium bisulfite service right into the ethoxylation activator. After nitrogen substitute and also temperature rise operation, ethylene oxide is included at 90 ° C to start the response, and the temperature is managed at 90-100 ° C. Pressure 0 ～ 0.1 MPag (scale stress). After adding 500Kg of ethylene oxide, develop at 90-100 ° C for half an hour, and after that dump.
The crude product (concentration 40-45wt%) synthesized in the previous action is sent out to the double-effect continual vaporizing recrystallizer, run in parallel, continually fed, and also periodically released, that is, the dilute service is progressed to the first-effect evaporator, as well as after initial After concentration, the focus reaches 55-60wt%. The concentrated remedy goes into the second-effect evaporator, as well as after additional concentration as well as dissipation to 72-75wt%, the focused service gets in the continuous crystallizer. The centrifuge centrifuges, the solid goes into the next procedure, and the mom alcohol returns to the second-effect evaporator to remain to participate in dissipation and also concentration. When the web content of ethylene glycol in the product gets to listed below 0.1%wt, it is considered certified, and also via analysis and also detection, the product pureness is more than 99.5 wt%.
A small amount of non-crystallizable raffinate is removed with 3 times solvent, and also the used extractant is dried alcohol, and the salt isethionate product is separated out in dehydrated alcohol, as well as a small amount of water and also natural impurities, such as ethylene glycol, Polyethylene glycol and isethionate will enter the fluid stage ethanol, then go into the centrifuge for centrifugation, as well as finally dry the crystals in a disc dryer at 120 ° C to eliminate a percentage of residual solvent impurities in the item as well as wetness. The utilized extractant ethanol is recuperated and reused. Extractant ethanol can be recouped by distillation.
