How to operate the system for introducing circulating water into a refinery unit? What should I pay attention to?

During the startup process of our unit (catalyst), once the reaction flow is well established and feeding is ready, circulating water is introduced into the unit: coordinate with the control team to increase the pressure of the circulating water, open the inlet valve of the cooler, and direct the condensate to the vent; once water is observed, close the condensate outlet valve and open the outlet valve. Regarding precautions, it is important to activate the cooler in a timely manner to prevent pressure buildup (we have encountered this issue before). Additionally, at the beginning of operation, if the water pressure is too high, it is necessary to use the return line to prevent damage to the pump. Another thing is to prevent low water pressure from causing air blockage. It affects the cooling effect.

Introduction must be gradual to prevent overloading the system; moreover, flushing and emptying are necessary!

Before introducing circulating water into the new unit, the following steps must be carried out: 1. The circulating water pipeline must be purged and pressure-tested. 2. Check all valves according to the process flow to ensure they function properly, clear the flow path, and remove the blind flanges used for pressure testing. 3. Verify that all orifice plates, flow meters, control valves, thermometers, and pressure gauges are properly installed. 4. If access to the pumps is required, ensure that the filters at the inlet of each pump have been cleaned and installed. 5. Water should be introduced into the unit slowly, with air being released from the end of the pipeline to prevent water hammer. 6. After the circulating water starts operating in the unit, it must run for at least 24 hours before stopping to clean the sediment in the circulating water tower, after which it can operate again

The pressure before entering the hydrogenation unit ≮ 0.4 Mpa (the pressure in the circulating water system pipes is 0.4–0.5 MPa). It is generally used in turbines, heat exchangers, water coolers, pumps, power units, and oil coolers, etc.

Under normal circumstances, the circulating water is first introduced into the device, as most of the circulating water in our device is used for heat exchange. The circulating water serves as the cold fluid medium for heat exchange, and therefore it needs to be introduced into the heat exchanger first.

Circulating water should be introduced into the device; if it is a new device, this should be done before commissioning. The valve should be opened slowly to flush the lowest points of the pipelines, and once clean water appears, the drain valve should be closed and the device connected to the water supply. If the device is being put back into operation after maintenance, such thorough procedures are not necessary – a simple flushing is sufficient.

The circulating water for the unit should be introduced when the utility system is put into operation; I’ll send you our procedures for reference – this is how we proceed for newly built units. 1. Notify the dispatch team to prepare fresh water for flushing the circulating water system. 2. Do not open the main valve of the circulating water outlet device first; instead, open the vent before the valve to drain water into the gutter for replacement. 3. Introduce fresh water to flush the inlet main pipeline, and open the high-point vent on the circulating water supply line to release any air trapped within the pipeline. Once the water is clear, disconnect the equipment from the circulating water inlet pipeline connections, open the inlet valves of all water-using devices, direct the water to the connection points and discharge it into the gutter; once the water is clear again, reconnect the connections properly. 4. For all heat exchangers that use circulating water as the cooling medium, first close the inlet and outlet valves and use a bypass line to circulate the water, in order to prevent dirt from entering the heat exchanger. 5. After visual inspection confirms that the water is clear in the drain before the main valve of the unit, open the inlet and outlet valves of each circulating water cooler, and close the bypass line. The shell side low-point vent is opened. 6. The circulating water main line must be unobstructed, as well as all its branch lines; clear water with no leaks (neither internal nor external) is considered a satisfactory condition. Otherwise, continue to flush the circulating water lines or report the issue for handling. 7. Introduce circulating water into the device, and inform the water supply and drainage team to open the main valve for the circulating water supply. 8. Boundary condition: The pressure before the system’s circulating water inlet device ≮ 0.4 MPa.

The person on the 9th floor already explained everything in detail. It’s essential to pay attention to the process and make sure it is corrected; moreover, fresh water and recycled water must not mix with each other

It should be “mutual stringing” instead of “mutual transmission”; sorry, I made a mistake

When introducing circulating water to devices such as coolers for cooling purposes, it is necessary to use a bypass line first to circulate out the dirt in the main pipeline; equipment should be brought online one by one to avoid overloading the piping system. Prevent air blockage.

Once the startup purging, pressure testing are completed and the conditions for introducing circulating water are met: 1. Check according to the process flow, ensure the flow is unobstructed, close the relevant valves and stop any backflow, and remove the corresponding blind flanges. 3. Verify that all orifice plates, flow meters, control valves, thermometers, and pressure gauges are properly installed. 4. Contact the dispatch team and the water plant to supply water to the device’s area; stop any backflow once water starts flowing. 5. Introduce circulating water into the equipment in accordance with the production schedule and requirements – first open the valve at the equipment’s outlet to allow backflow, then open the inlet valve; close it again after water starts flowing, and then reopen the outlet valve. 6. After circulating water begins to flow within the device, maintain the necessary pressure, which should be no less than 0.4 Mpa; if necessary, contact the water supply department for assistance.

After the purging is complete, preparations for introduction are carried out: the flow path is checked to ensure there are no miswired connections, and the power department is informed to prepare the water supply. Before entering the device, the wastewater is drained completely first, followed by the introduction of fluid; the quality of the pipelines and welds is also verified. Once the water pressure is stable and the flow rate is consistent, everything is in order and OK

The circulating water system must be purged and pressure-tested. 2. Check all valves according to the process flow to ensure they are functional, clear the flow path, and remove the blind flanges used for pressure testing. 3. Verify that all orifice plates, flow meters, control valves, thermometers, and pressure gauges are properly installed. 4. If access to the pumps is required, ensure that the filters at the inlet of each pump have been cleaned and installed. 5. Water should be introduced slowly, with venting at the end to prevent water hammer. 6. After the circulating water starts operating, it should run for at least 24 hours before stopping to clean the sediment in the circulating water tower, after which it can operate again

I have a few additional suggestions: 1. The circulating water should first be introduced into the equipment area; after venting at the higher points, it should circulate among all users who need water. Since the purpose of cooling water is to remove excess heat from the equipment area, it is correct to use cooling water first in order to prevent damage to the cooling equipment. 2. Before the circulating water enters the plant area, preliminary preparations must be carried out first, such as pre-film formation of the circulating water. 3. The return line for circulating water must be unobstructed to ensure no pressure buildup. For now, that’s all for the additions