【Q&A Question 126】2016.08.24

The principle is to run through the process, flush the pipelines, and test-operate the unit. Precautions: Be sure to disconnect the flange; it is strictly prohibited for welding slag to enter the pump body

Principle: Do not pour debris into the equipment; connect the pipelines properly before combined operation. Note: Close the blind flange, use the bypass line first before passing through the heat exchanger.

Streamline processes, remove debris inside pipelines, monitor equipment operation status

When starting the water interconnection, the flow meter or control valve bypass should be used first; once normal operation is achieved, then the flow meter or control valve can be used

Follow the process; carry out the procedures as outlined

1.1.1.1. Purpose of water transportation: 1) To further remove impurities such as rust, slag, and sediment remaining in the equipment and pipelines. Prevent pipeline blockages and damage to valves, orifice plates, pumps, and other equipment, ensuring that the equipment and pipelines remain unobstructed. 2) Put into use various measurement and control instruments to test the cold-state performance of these instruments and control valves. 3) Conduct technical training and accident drills to help operators become more familiar with the procedures. 4) Observe the operating performance of the pump over an extended period of time. 1.1.1.2. Meeting condition 1): The equipment and pipelines have been flushed and purged ； The single-unit trial operation was successful, confirming that it can be put into operation at any time. 2) The control instrument systems for flow rate, liquid level, etc. have been fully installed, verified, and meet the requirements. 3) The supply of water, electricity, gas, and air is normal. 4) The water transport system has been isolated from those that do not participate in it. 5) All purging valves for nitrogen, steam, etc. in the water transport section have been closed, and all drain valves have been closed. 6) Ensure unobstructed drainage paths behind the safety valves of all towers and vessels, and activate the safety valves. 1.1.1.3. Precautions for water circulation 1) When filling the equipment with water, open the top vent and the bottom drain to remove most of the contaminants. Once the water is clear, close the bottom drain valve, then refill the system with water until it is confirmed that the system has been thoroughly cleaned, after which start circulating the water in the system. 2) Install temporary filter screens at the pump inlets before water transportation; be careful to ensure that the motor does not experience overcurrent when pumping water. Blind flanges should be installed at the inlets and outlets of the reboilers at the bottom of each tower, and these flanges should be removed after the water has been completely replaced. 3) When starting the water interconnection, the flow meter or control valve bypass should be used first; once normal operation is achieved, then the flow meter or control valve can be used. If a clog is detected in the filter screen during water conveyance, it should be removed and cleaned promptly, or water supply should be stopped to prevent the pump from running dry. 4) During the water transfer process, flush the valves of various bypasses and connecting lines, as well as dead corners, sampling points, vent points, and the pipelines at both ends of the control valves, every few hours. Also, make sure to open the low-point vents in each tower, container, and pipeline in order to remove debris. 5) In water intermodal transport, planned technical training and accident drills should be carried out to help operators become more familiar with the processes. 6) In water intermodal transport, it is necessary to frequently switch machine pumps, instruments, and valves, so that operators can master the methods of switching machine pumps as well as the use of control valves and instruments. Note: During water transport, the gauge is not calibrated; only its operational trend is observed (as the indications differ due to the differences between water and oil operating conditions). 7) During the water transportation phase, various tests on the pump must be carried out as specified, with proper recording kept. 8) If a rapid drop in pressure is observed during water transport, it is necessary to check whether the process is correct or if there are leaks in the equipment and pipelines, and take action promptly. 9) After the water transfer is completed, check whether the drainage system is unobstructed; open the low-point drains of the process pipelines and equipment to drain any remaining water, then close the valves and restore the blind flanges to their original position. 10) After the water intermodal transport is completed, open the large cover of the pump inlet filter, remove the temporary filter screen, and reinstall the original filter screen. 11) During the water transfer process, wastewater from each piece of equipment should be drained separately into the underground oil waste tank system. It is necessary to check whether the wastewater drainage pipes are unobstructed; meanwhile, the operation of the underground oil waste tank system should also be inspected.

1. Water interconnection operates according to the water circulation process, and it is necessary to prevent water from entering other areas that are not involved in this interconnection. 2. When water passes through the cooler, heat exchanger, and control valve, if there is a bypass line, it should flow through that line first; only after the water becomes clean should it pass through the heat exchanger and control valve. 3. If a clog is detected in the filter screen or pipelines during water transportation, the filter screen should be removed promptly for cleaning, or the clogged area should be identified and cleared. 4. In water intermodal transport, it is necessary to control the flow rate at the pump outlet so that it does not exceed a certain level, in order to prevent the motor from experiencing overcurrent (with the motor’s rated current as the limit). 5. During combined transportation, the standby pump should be switched in for use. 6. After filling equipment such as towers, vessels, and heat exchangers with water, drain water from all low points before starting the water commissioning. 7. When the circulating water becomes dirty, it can be partially drained depending on the situation, fresh water can be added, or all of the water can be drained to restart the circulation process. 8. After the water circulation is completed, the entire system should be drained of water promptly. At this time, it is important to ensure that the pressure in all containers is equal to that of the atmosphere, in order to prevent a vacuum from forming inside the containers during drainage and thus avoiding damage to the equipment. 9. After the water intermodal transport is completed, a simulation report for the water intermodal transport vehicle should be filled out. 10. When conducting water interconnection in winter, anti-freezing measures must be given full consideration.

Principle: Water circulation refers to the operation of water within the distillation system; it is important to maintain unobstructed flow during this process, and on-site checks should be carried out to detect any leaks. The main purpose of water circulation is to use water to remove impurities from the pipelines in the distillation system.

It should be done in all areas where water can get in. Flush the pipelines, ensure the flow is unobstructed, test the equipment, train the personnel, and check for any leaks.