The superhot water sterilization of wfi system mainly involves heating the water for injection in the storage and distribution system to 121℃, and then circulating at this temperature for 0.5h to complete the sterilization of the storage and distribution system of wfi.The heating object in the sterilization of superhot water is injection water, which does not need to add other materials, and has no pollution risk and high safety.The amount of water for injection has a great influence on heating time, steam consumption and system operation safety. Therefore, it is necessary to control the amount of water in the storage tank before heating.If there is too much water, heating time and steam consumption will increase, increasing operating costs.If too little, when the water for injection is heated, it is easy to cause cavitation of the circulation pump and damage the seal of the circulation pump.The heating methods of superhot water sterilization are storage tank jacket heating and heat exchanger heating. Due to the long time and poor temperature uniformity of storage tank heating, heat exchanger heating is mostly adopted in the newly built system.The heat exchanger for sterilization can meet the sterilization requirements by increasing the heat exchanger for the 70℃ cycle of the maintenance system, with little additional investment.After hot water sterilization mainly control the temperature of heating water for injection, convenient detection, high accuracy, simple control process, stable disinfection effect.Therefore, hot water sterilization is the most widely used sterilization method in the storage and distribution system of water for injection.
Pure steam sterilization
The pure steam sterilization of wfi system first needs to empty the whole system, and install the hydrophobic device and temperature detection unit at all the low points (which have no role in ordinary use), and then pass the pure steam (> 121℃) to monitor and control the hydrophobic point temperature.Its sterilization process operation is more complicated, the system low point is more, increase the cost more.Therefore, the current wfi system is mainly sterilized by hot water. In some old workshops, pure steam is still used to sterilize wfi system due to the equipment transformation and concept change.