Reverse osmosis membrane disassembly, installation and replacement process

Preparatory Work

1. Prepare all tools that may be used during construction;

2. Clean the upstream water supply pipeline;

3. Carefully assess the water quality;

4. Check the pipeline for leaks;

5. Prepare a water-soluble lubricant (chemically pure glycerol);

6. Ensure that all components and chemicals are complete;

7. Check the operation and normal effluent of the pretreatment system.

Disassembly of Old Reverse Osmosis Membranes and Installation of New Membranes

1. Disassemble the pressure vessel of the reverse osmosis membrane, unify all end caps and components, and store them in order.

2. Remove the old reverse osmosis membrane elements from the pressure vessel and rinse the pressure vessel clean.

3. Take out the new membrane element and check whether the position and direction of the brine seal on the element are correct (the opening direction of the brine seal must face the water inlet direction).

4. Push the end of the membrane element without the brine seal into the membrane shell from the water inlet end of the pressure vessel parallel to the water inlet end until the element is about 10 cm outside the water inlet end of the pressure vessel.

5. Insert the connecting pipe between the elements into the central pipe. Before installation, apply a small amount of glycerol lubricant to the "O"-ring on the connector. If not, you can also directly wet it with qualified pretreated water.

6. Take out the second membrane element, check whether the position and direction of the brine seal on the element are correct, hold the element, and insert the connecting pipe of the first element into the central pipe of the element, and push the element into the pressure vessel parallel until the second element is about 10 cm outside.

7. Repeat the steps until all elements are installed in the pressure vessel, transfer to the concentrate end, install the connecting pipe on the central pipe of the first element, the number of membrane elements that can be installed in a single pressure vessel is determined by the length of the element and the pressure vessel, and install the thrust ring at the concentrate end of the pressure vessel during installation.

8. Check the "O"-ring on the element adapter, insert the element adapter into the concentrate end plate, align the element connecting pipe, and push the concentrate end plate assembly into the pressure vessel parallel; rotate and adjust the concentrate end plate assembly to align with the external connecting pipe; install the end plate retaining ring.

9. Push the membrane element from the inlet side to the concentrate side until the first installed membrane element is firmly in contact with the concentrate end plate.

10. Install the inlet end plate. Before installing the inlet end plate, in order to prevent axial movement and impact between the elements during system startup and shutdown, shims (5 mm thick) can be used to adjust the gap between the membrane elements and the end plate.

11. Repeat the above steps to install membrane elements in each pressure vessel and connect all external water inlet, concentrate, and product water pipelines.

Equipment Debugging

1. Pre-debugging inspection and preparation, including the following parts:

Configure measuring instruments and calibrate each instrument;

Set sampling points at various stages of the system, and correctly set interlocking, delay, and alarm devices;

Check the pressure vessel and cleaning pipeline connections, and tighten all joints;

No-load test run of various rotating equipment such as water pumps to ensure correct direction and good lubrication;

Open the product water discharge valve and the concentrate discharge valve;

Before starting the high-pressure pump, adjust the opening of the high-pressure pump outlet valve to control the membrane system water inflow to less than 50% of the operating water inflow.

2. Check all valves and ensure that all settings are correct. The membrane system product water discharge valve, water inlet control valve, and concentrate control valve must be fully open.

3. Use low-pressure, low-flow qualified pretreated water to remove air from the membrane elements and pressure vessels. All product water and concentrate during this process should be discharged to the sewer.

4. During the flushing operation, check all valves and pipe connections for leaks.

5. For dry membrane systems, continuous low-pressure flushing should be performed for more than 6 hours, or flushed for 1-2 hours first, soaked overnight, and then flushed for about 1 hour. During low-pressure, low-flow flushing, no scale inhibitors should be added to the pretreatment section.

6. Re-confirm that the product water valve and concentrate control valve are in the open position.

7. The first start-up of the high-pressure pump must be in a state where the water inlet control valve between the high-pressure pump and the membrane element is nearly fully closed to prevent the impact of water flow and water pressure on the membrane element.

8. Start the high-pressure pump.

9. Avoid over-flow and over-pressure impact on the membrane system. After the high-pressure pump starts, slowly open the high-pressure pump outlet water inlet control valve to uniformly increase the concentrate flow rate to the design value. The pressure increase rate should be less than 0.07 MPa per second.

10. While slowly opening the high-pressure pump outlet water inlet control valve, slowly close the concentrate control valve to maintain the concentrate discharge flow rate specified by the system design, observe the system product water flow rate at the same time, and gradually adjust the recovery rate to the design value.

11. Check whether the dosage of all chemicals is consistent with the design value, and measure the pH value of the influent.

12. The system runs continuously for 1 hour. When the product water is qualified, open the qualified product water delivery valve first, then close the product water discharge valve, and supply water to the subsequent equipment. Record all operating parameters of the first group. The above adjustments are generally carried out in manual operation mode, and after stabilization, the system is switched to automatic operation mode.

13. After continuous operation for 24-48 hours, check all recorded system performance data, including influent pressure, pressure difference, temperature, flow rate, recovery rate, and conductivity. At the same time, sample and analyze the influent, concentrate, and total system product water. Confirm that the equipment is running normally and the construction is completed.