Operating Instructions for EDI (Ultrapure Water) Module

I. Startup

1. Overview
The module needs to be regenerated first. During regeneration, simply start the operating system as you normally would, but the produced water needs to be discharged until the produced water is qualified. The produced water from this device is discharged back to the pure water tank.
2. Startup (The following operating procedures are only applicable to the initial debugging phase of the equipment)
Before starting the debugging, the following items need to be checked (during debugging or after maintenance): The entire device meets the continuous operation conditions, all valves are closed, and the rectifier is in the "off" state.
Startup steps:
Fill the system with water that meets the inlet water conditions.
Set the produced water flow rate.
Determine the concentrate flow rate.
Set the concentrate discharge flow rate, set the concentrate inlet pressure, and set the concentrate outlet pressure.
Start the rectifier.
a. Pipeline water filling
Slightly open the produced water valve, produced water discharge valve, and concentrate discharge valve. Slowly partially open the inlet water valve to vent. Close all valves.
b. Debugging steps
Determine the produced water flow rate: Open the produced water valve 10-20%; Slowly open the water supply valve, and adjust the produced water valve according to the produced water volume requirement to make the produced water flow rate 3m3/h. Determine the concentrate flow rate: The recovery rate of the EDI system of this device is not less than 85%, once the recovery rate is determined, the concentrate discharge amount can be calculated as follows:
Concentrate discharge amount = Produced water amount × (1-R) / R (R is the recovery rate)
The minimum concentrate flow rate of this device must not be less than 200L/H
Open the concentrate discharge valve to 10-20%, open the concentrate inlet valve, adjust the concentrate inlet pressure to a pressure value lower than the water supply pressure by 2-5psi, adjust the concentrate discharge valve to make the flow rate 150L/H-250L/H (the specific flow rate is determined by the inlet water flow rate and recovery rate), repeatedly adjust the valve opening to make the concentrate outlet pressure lower than the freshwater outlet pressure by 2-5psi, and the flow rate meets the requirements.
c. Start the EDI power supply
After confirming that the system flow rate is normal, supply power to the EDI module, and adjust the current size to adapt to the produced water quality. In general, the DC power supplied by the system power supply is a constant current operation mode, that is, it operates under a given current condition.
The current adjustment must be operated slowly.

II. Shutdown procedure

1. System shutdown

The startup and shutdown of this device are interlocked and automatically operated. If you need to stop the EDI device, you can set the EDI switch to the "off" position. (This achieves the shutdown of the EDI device)
2. System interlocked shutdown
When the system experiences water shortage or water supply pump shutdown /failure, the EDI device automatically stops. When the electrical control system experiences overheating, overload, or phase loss, the EDI device automatically stops.
3. Long-term shutdown
If the system stops for more than three days, long-term shutdown and sealing treatment must be carried out to prevent microbial reproduction. Close the system's inlet and outlet valves to maintain moisture, and seal the four interfaces of the module with the original dust cover. After long-term shutdown, the module may need to be regenerated.
III. Operating instructions
1. Operating pressure

Operating pressure is also a key operating parameter. In order to prevent concentrate from possibly seeping into the freshwater chamber and causing a decrease in the produced water quality, the concentrate inlet and outlet pressures are lower than the freshwater inlet and outlet pressures 2-5Psi. Because the pressure drop resistance of the concentrate chamber is relatively small, the difference between the concentrate inlet pressure and the freshwater inlet pressure may be larger.

However, if the produced water outlet pressure is too much higher than the concentrate outlet pressure (exceeding 0.7bar), the produced water quality will decrease. The system pressure and flow rate are required to operate stably. Under normal operating conditions, once the debugging is completed, the valve state can be maintained for operation, and a prohibition tag can be hung.

2. Inlet water
When the inlet water meets the requirements, the EDI device can operate stably for a long time. At the same time, attention should also be paid to the fact that in the initial stage of RO water production, the product water should be discharged without entering the pure water tank.
3. Operation
a. After checking that the electrical circuit and control circuit are correct, turn on the main power switch (inside the panel), and the system is powered on,
b. Set the EDI switch to the "off" position, and the EDI system will stop.
IV. Control system description
1. Control system
When the electrical control system encounters abnormal conditions such as phase loss, overcurrent, and overvoltage, the power supply device has no DC output and alarms. The system has an interlock device to achieve automatic control and interlock protection of the system.

When the pure water pump starts or stops, the interlock starts or stops the EDI device.