Freeze and condensation prevention

This should be part of the design at the initial stage of construction; measures taken in certain areas include electric heating, steam pipe heating, installation of insulation layers, provision of heating systems, and insulation chambers (rooms), etc.

Ensure proper heat tracing (steam, low-temperature heat, electric heat tracing), strengthen inspections before, during, and after shifts, monitor temperatures continuously, and carefully watch the curves of key instruments to prevent straight lines from appearing

What the construction team left behind differs greatly from the design, resulting in leaks and freezing problems every year.

First, it is necessary to determine whether it is water-based heating or steam-based heating. Generally speaking, there is a low chance of freezing in the case of water-based heating, as such systems usually come equipped with a heating water pump. It’s sufficient to keep an eye on the pump outlet pressure. The possibility of freezing due to steam tracing is relatively high, with the main influencing factors being: 1. The stability of the steam pressure and its level. 2. If the steam pressure is very high, then check for any areas where pressure is building up in the return water. 3. In areas where there is no pressure buildup, it is necessary to check whether the heat tracing for freezing prevention is too long; a too-long heat tracing results in low pressure in the return water, which leads to poor flow of the return water and an increased risk of freezing. 4. It is also necessary to check whether the route of the heat tracing wire has too many bends, which could result in too low a pressure drop and thus freezing.

1. Before winter arrives, conduct a thorough inspection of the equipment to prepare it for the winter period. This includes providing heat tracing for equipment and pipelines, checking for any dead ends or areas where water may accumulate, and ensuring that the drain valves function properly. 2. For equipment and pipelines that will be shut down during winter, it is necessary to open the drain valves at the lowest points to release any accumulated water, and then use compressed air or low-pressure nitrogen to clear out any remaining water. 3. Equipment that contains water and is temporarily shut down in winter must be protected from freezing. 4. During winter operations, it is important to ensure that the drain traps at the lowest points of the steam pipelines are functioning properly. 5. Fire protection pipelines in the plant area and buildings should be protected from freezing; insulation can be added near air vents, or the ends of the pipelines can be slightly opened to prevent freezing. 6. If a valve freezes and cannot be opened, especially an iron cast valve, it is forbidden to try to force it open using tools such as wrenches. Instead, the valve should first be closed, then warmed up with steam (or hot water) before attempting to open it again. 7. Outdoor pumps that are not in use temporarily should have their circulation cooling water systems kept running in winter, or they should be completely isolated at the source to prevent damage from freezing. 8. When the plant stops receiving water and steam in winter, all steam and water pipelines, as well as the equipment itself, should be thoroughly cleaned using compressed air. They should also be isolated from the main systems of the plant, or the excess fluid should be drained elsewhere. 9. During the winter shutdown period, heating devices, heat tracing for pipelines, and steam pipelines should continue to receive a small amount of steam. Cooling devices and cooling water pipelines should also continue to have a slight flow of water to keep them unobstructed and prevent freezing

For inspections of critical pipelines, ensure that there are no blind spots in the heating system, maintain unobstructed flow in the heated pipelines, and promptly vent and purge any unnecessary pipelines.

After the shutdown, carry out the necessary technical upgrades; don’t create trouble for yourself.

Headaches can occur even at minus 9 degrees; most pipelines cannot be properly insulated against freezing. In winter, ensuring proper heating is essential for preventing freezing, and it is necessary to maintain smooth circulation. Issues with the heating system may arise due to insufficient pressure in the pipelines, oil contamination in the heating fluid, blocked traps or check valves, or too shallow bends in the heating pipelines, which result in low flow rates. Maintenance, replacements, and proper drainage should be carried out before winter arrives to ensure smooth operation of the heating system. Another thing to note is that any area that is a dead corner or where the fluid does not flow for extended periods should be provided with heat tracing, including oil lines, fuel gas lines, etc., unless it can be ensured that there is no water at all in the fluid – not even trace amounts. Idle pipelines should be purged completely and isolated using blind flanges.