Key Points for Preventing Freezing and Condensation in Chemical Plants (I. Useful Tips)

Drainage operation procedures: I. For equipment and pipelines that operate intermittently on the ground or are not in use for extended periods, drainage procedures are as follows: 1) Close the relevant valves; if necessary, install blind flanges to prevent leaks inside the valves； 2) Open the high-point vent valve and the low-point drain valve to empty the material inside the equipment ； 3) Purging and replacing residual materials ； 4) Keep the normally open low-point drain valve open and inspect it regularly. II. Emptying of facilities and pipelines in underground valve chambers: For underground valve chambers and outlet pipes that are not in use or are used intermittently and do not have heating, the root valve inside the valve chamber should be closed, the water above the valve should be drained using a drain valve, and this drain valve should remain open at all times. III. Emptying of equipment and pipelines that are to be shut down or used intermittently: After use, the medium within the pipes should be emptied promptly, and the pipes should be purged with nitrogen ； If possible, it can be placed in a insulated building.

The faucets in Lianyungang can freeze even when water is flowing; it was in 2015: lol

Specifications for insulation installation: 1. Insulation of equipment, pipelines, and their accessories should take into account the problems that have occurred in previous years; this task requires careful inspection and improvement. Special attention should be paid to the insulation at the ends of equipment and pipelines, as well as at blind ends, where no heating is provided and freezing prevention relies solely on the temperature of the material, to ensure that proper insulation is in place. II. Sealing and insulation of indoor spaces such as factories: Check to ensure that the doors, windows, and door curtains in the factory are in good condition, and activate the heating system inside the factory promptly. III. Sealing and insulation of fire protection facilities and underground valve chambers: For fire protection facilities that do not have heating systems (such as water cannons and fire hydrants), anti-freezing coatings should be applied in advance ； For valve chambers, seal them in advance using plastic sheeting, and apply insulation measures if necessary.

Specifications for installing heat tracing: Hot water heat tracing is suitable for use in situations where the operating temperature is not high or where high-temperature heat tracing media cannot be used. It is important to pay attention to the flow rate to prevent freezing due to too low a flow rate. Before putting the steam tracing into use, dehydration operations must be carried out to avoid water hammer. After the steam tracing is operating properly, the traps should be adjusted and inspected to ensure proper drainage. For electric trace heating, a temperature control loop must be activated to prevent the pipes from becoming too cold or overheated. It is also necessary to pay close attention to the insulation inspection, in order to prevent temperature abnormalities caused by water ingress due to damaged insulation, as well as damage to the electric heating system.

Cycle operation specifications: The cycle anti-freezing and anti-condensation method is primarily used for equipment and pipelines that operate intermittently or are not in use for extended periods, where the aforementioned methods (emptying, insulation, heating) have not been employed for anti-freezing purposes, or where such methods are insufficient to meet the requirements for anti-freezing and anti-condensation. By circulating the material exiting the equipment back to the inlet of the standby equipment, this method is commonly used to prevent freezing and condensation in standby mechanical equipment, either through a bypass line adjacent to the check valve at the pump outlet or by creating an opening in the disc of the check valve. It involves connecting the device’s inlet pipeline to its outlet pipeline through a bypass; this method is commonly used to prevent freezing of the heat exchange inlet and outlet pipelines when they are not in use. A pipeline with a smaller diameter is connected in front of the inlet valve and behind the outlet valve of the heat exchanger, thereby allowing the fluid in the inlet and outlet pipelines to circulate. Under normal operating mode, carry out a small number of cycles; generally, it is advisable to close the outlet valves of the standby equipment as much as possible to reduce the volume of fluid circulation, thereby meeting the anti-freezing requirements. A small amount of medium is discharged continuously or intermittently; this method is mainly used in cases where it is not possible to install anti-freezing measures at the end of circular pipelines, such as in hose stations, drain lines for storage tanks and valves, drain valves at the lowest points of steam pipelines, and eyewash stations.

Yes, there is a hazardous task at the utilities center: going to the cooling tower and using long bamboo poles to break up the ice spikes when severe cold sets in.

The fact that running water also freezes indicates: 1. The external insulation is not properly installed； 2. The flow rate of the water inside the pipe has decreased.