Summary of winter anti-freezing measures

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It’s very useful material; everyone can take a look. Freezing prevention is the biggest issue for the safe production of chemical enterprises in winter. The importance of anti-freezing is understood by all operators; the issue now is to achieve savings while still ensuring safety against freezing, without allowing water to flow at an excessive rate. Fire protection piping systems are equipped with electric heating; energy conservation and emission reduction are important issues for us, and they are also the focus of our inspections. Companies should always pay attention to the local weather forecasts and take early preparations based on weather changes, establishing appropriate guidelines for their teams. General measures to prevent freezing and condensation are formulated according to the characteristics of each facility, and special attention should be paid to aspects that the teams may not be able to handle or consider. Ensure proper venting, condensate drainage, and heat tracing in key areas such as water, steam, air, and oil systems to maintain unobstructed flow, and conduct regular inspections. Automatic electric heat tracing for equipment piping systems ； The remaining anti-freezing pipelines remain under continuous electric heating. To prevent freezing in chemical plants during winter, the main focus is on ensuring the normal operation of the processes. This involves checking whether the media inside the equipment and pipelines are affected by low temperatures in winter and whether this affects the requirements of the processes. The main solutions are to use rock wool for insulation or to install electric heating elements for warming. There are several ways to prevent freezing in winter: one is to use heating and insulation measures, with electric heating and steam heating being the two types of heating available. Second is evacuation: any unused pipelines should be emptied and purged promptly. Third, make small emissions at the low point or establish circulation to ensure flow. Common methods for anti-freezing include steam tracing, electric tracing, insulation materials, and hot water tracing. 30 Tips on Anti-freezing in Chemical Plants 1. Ensure proper personal protection, wear warm clothing, and take precautions to prevent slipping when moving up and down the towers during inspections. 2. Strengthen dehydration efforts by promptly removing water from various dehydration points to prevent freezing and blockages. 3. Pay attention to the level gauges in use; if the angle valves at the top and bottom of these gauges freeze up, it will affect the accuracy of the measured level. If the transmitter associated with the level gauge freezes up, it will impact mechanical movement and current flow, thereby affecting the accurate measurement of the level. 4. The temperature of the circulating water should not be allowed to drop too low; it must remain above 8 degrees. If it falls below 8 degrees, freezing in the auxiliary lines of the cooler can occur, and in severe cases, the pipes may crack as a result. 5. Insulate the pipes in the stagnant water areas of the workshop’s circulating water system ； The deactivated circulating water pump was subjected to reverse flow measures and its contents were completely drained. 6. For equipment that is not in use in the workshop, such as make-up water pumps, circulation water pumps, coolers, condensers, etc., measures such as draining water and conducting regular inspections should be taken. The compressor cooling water is checked regularly by the operator to ensure that the water valve remains open. 7. If a liquid hydrocarbon pipeline freezes and gets blocked, be careful to avoid physical explosions when using steam to clear the pipeline; do not force the cleaning process, rather preheat it gradually. 8. On-site pressure gauges can also give false readings in cases of freezing and blockage; judgment should be based on experience. Any uncertainty should be reported promptly for handling. 9. When purging frozen and blocked pipelines, use steam to purge the elbows. 10. Pay attention to enhanced liquid removal from natural gas pipelines to prevent liquids from entering the boiler. Check the natural gas lines to prevent blockages caused by frozen crystal structures. 11. Strengthen inspections to monitor the temperature at various locations. 12. The water supply pipeline should be kept from being completely closed to maintain a continuous flow of water. 13. For decommissioned equipment, blind flanges should be installed at the connections to the production system, any accumulated water must be drained, and the area should be purged thoroughly. For equipment left outdoors and exposed to the elements, take measures to prevent water, snow, and ice from damaging it. For outdoor equipment, the frequency of routine inspections and turning operations needs to be increased. 14. For equipment used in production and daily operations, as well as those that are temporarily out of use, steam pipelines, and control valves must be equipped with anti-freezing insulation measures. Any accumulated water should be drained, or a system that maintains a small continuous flow of water and steam should be employed to achieve both anti-freezing effects and water conservation. After the supply of water and steam is stopped, the systems must be thoroughly purged. 15. Strengthen routine inspections for dehydration; check for dehydration at the lowest points of various equipment and pipelines. The cooling water supply to pumps must not be interrupted, and heating systems must remain functional. Pressure gauges and level gauges should be checked regularly. Steam and water hose connections as well as other related components must ensure continuous steam output and flow of water. 16. Valves whose switches do not move should not be forced to be switched; vehicles whose control panels do not function should not be operated. 17. Frozen cast-iron valves should be slowly heated using warm water or a small amount of steam to prevent damage from sudden heating. 18. Construction and domestic water should be directed into gutters or areas that do not interfere with traffic, and ice slush should be removed at all times. 19. Strengthen management by establishing records for anti-freezing and anti-condensation measures (including accident logging, the condition of anti-freezing and anti-condensation equipment, and pipelines prone to freezing and condensation). 20. Valve chambers, fire hydrants, and pipe trenches in low-temperature areas should be inspected one by one to drain any accumulated water, and anti-freezing and insulation measures should be taken. 21. Heating with high-pressure steam is strictly prohibited; care must be taken to prevent high-pressure steam from entering the low-pressure system. The high-pressure and low-pressure steam return pipes must not be connected to each other. A pressure reducing valve should be installed on the pipeline of the steam heating radiators; the pressure gauge connected to this valve must be calibrated properly. The radiators must be tested for leaks by introducing steam before they can be used. 22. Whenever working at heights, it is necessary to ensure that all water accumulation, snow, and ice in the work area have been removed before proceeding. 23. Therefore, for steam pipelines (except fire protection steam), close the root valve and the wall valve, open all drain valves to drain any remaining water, and purge them with nitrogen. 24. All drain points must be drained every hour. 25. After shutting down the circulating water system, the low-point drain must be opened to remove all water, and the area should be blown clean with air. 26. The drainage pipelines of the adsorption tower, desulfurization tower, water washing tower, and gas-liquid separator outside the workshop are protected against freezing using electric heat tracing. Freezing is prevented by promptly draining the water separators and coolers in the workshop after they are shut down. 27. When indoor heating is turned off, safety facilities such as tap water, eye wash stations, and fire extinguishers in the workshop are kept from freezing using electric anti-freezing systems. 28. If water is spilled on the workshop floor or platforms, clean it up immediately to prevent freezing. Workshop staff should enhance their safety and precaution awareness when going on platforms and climbing stairs. 29. When workshop personnel carry out maintenance work on the framework and the requirements for working at heights are met, all necessary safety precautions must be taken: wear safety helmets, fasten safety belts, and ensure that there is someone to supervise the work. High-altitude work carried out in conditions of gusts reaching force 6 (wind speed of 10.8 M/S) or higher constitutes special high-altitude work, and such work can only be undertaken with the approval of the general manager. In case of rain or snow, clean the stairs promptly. 30. During this period, workshop staff should increase the frequency of inspections; if any abnormalities are detected, they must report them to their superiors promptly. Anti-freezing measures for pipelines in winter: 1. For water lines used in processes that are installed above ground and require a low volume of water flow, it is necessary to ensure that there is a drain valve at the end of the pipeline to maintain a continuous flow of water and prevent freezing; where possible, insulation should be added to the pipelines. 2. For water lines that are used intermittently, electric heating tapes must be installed for insulation; otherwise, they cannot be used. 3. For water lines that are not in use during winter, the flanges on both ends should be removed to drain all the water stored within them. If possible, industrial air should be used for purging to ensure that the pipes do not get filled with water again. If the valves are not airtight, blind flanges should be installed at the flanges on both ends, and these should be registered and labeled accordingly. 4. For some pipelines that are not used in normal production, as they remain unused for long periods, water may accumulate in their dead corners and freeze; once these pipelines need to be used, this can lead to blockages and disrupt production. For such pipelines, before winter arrives, it is necessary to flush and purge them with an appropriate flow rate, then close the relevant valves to keep them in a standby state. 5. For the fire hydrants in the fire water supply system, as well as the valve chambers for these systems, it is necessary to close the valves located in those chambers and drain the water from the hydrants, so that they are ready for use at any time. A double-layer manhole cover should be used in the fire well (one of which is a thermal-insulating manhole cover). Freezing occurs: Once the equipment freezes, it should be thawed using steam or hot water. The thawing of cast iron pipes and equipment must be done slowly to prevent cracking. It is prohibited to heat frozen pipes or equipment while they are still sealed; first, the seals must be removed to allow air to escape. Horizontal pipes should be thawed from bottom to top, while vertical pipes should be thawed from top to bottom. Any cracks that appear must be reported.