What are some points worth considering regarding freeze protection design and plant management in the northern chemical industry?
Thread Content
I. Safety aspects: How are fire hydrants, fire pumps, and the fire protection pipelines on the ground protected from freezing in terms of fire fighting? How do outdoor eye wash stations on site prevent freezing? II. In terms of process: How to prevent freezing of intermittently used water sources, such as recycled water, condensate, steam, industrial water, and desalinated water? Process liquid phase with a lower freezing point, 1,4-butanediol? III. Environmental protection: What are the pipes used for receiving wastewater and ensuring its discharge meets regulatory standards? The low-temperature resistance of bacteria that treat wastewater? Atmospheric emissions, nitrogen monoxide and nitrogen dioxide – clean coal combustion technologies for winter heating? ?
1. Safety, with electric heat tracing available； There are more options in other aspects; choose according to the specific situation – hot water, steam, or electric heating can all be used
The design takes into account burial, drainage when out of use, reliable electric heating, and hot oil heating.
Considering burial in permafrost, the pipeline equipment used must take into account provisions for drainage or self-circulation； Thermal insulation needs to be considered comprehensively, especially for the cecum ； Natural gas should be given priority as a fuel source
Empty the fire protection piping network; keep the eye wash stations flowing continuously. Any sections of the water supply system where flow is interrupted should also be kept flowing. The melting point of dibutylene glycol is around 20 degrees, so steam heating should be considered. The return water bypass on the outdoor circulating water equipment is open
First: The entire pipeline needs to be insulated. Next, it is necessary to determine whether the water temperature is close to the outdoor temperature or if it is heated. If it is at room temperature, then an electric heating tape should be added inside the insulation layer of the fire protection piping. Eye wash stations generally use electric heating systems, or explosion-proof electric heating eye wash stations. If the water temperature is above 10 degrees, only the insulation layer needs to be added, and the eye washer should be designed with a drainage system to prevent freezing.
Safety aspect: The fire-fighting water is generally located below the ground frost protection layer, so no concerns are needed in winter. Dump-type fire hydrants are used, and they can automatically drain any remaining water after the valves are closed in winter. When installing the eye washer, connect the main valve at the root of the main pipeline; this prevents freezing without the need for automatic drainage of the remaining water. In terms of the process: regarding the water and steam used at various stages, on one hand, valves should be installed at the source in the main circulation system to allow for immediate use whenever needed; on the other hand, heat tracing should be considered, or several lines can share a single heat tracing line. Electric heat tracing can also be considered, though the cost is relatively high. In terms of environmental protection: for wastewater treatment, pipe racks are still the best option, as they result in low maintenance costs. There are no issues with bacteria, and as long as the water temperature is maintained properly, everything will be fine. As for meeting environmental emission standards, dust removal as well as desulfurization and denitration facilities need to be considered.
Fire hydrants can be in the form of fire valve chambers, and process pipelines can be insulated and equipped with electric heat tracing.
The selection of insulation measures is particularly important
I. Safety aspects: 1. For fire hydrants and fire monitors used for firefighting, the control valves are generally located below the permafrost layer. An automatic drainage valve should be installed behind the control valve, and gravel should be placed at that location to ensure that the water drained away seeps away quickly and does not accumulate； 2. The fire protection piping network on the ground should be equipped with boundary valves; there should also be drain valves behind these valves, as well as valve chambers. In winter, the boundary valves should be closed and the drain valves opened to drain the water accumulated in the pipelines. 3. We stop using the outdoor eye wash stations on site in winter; we can replace them with some indoor ones during that period, or else install electric heating – it’s essential to ensure that heating is provided in every nook and cranny II. In terms of process: It is recommended to add steam heating or electric heating for the intermittently used water source ； Circulating water to enhance anti-freezing pipelines ； Condensate ； Steam adds a hydrostatic separator at the end ； Add steam tracing to industrial water pipelines ； Keep the desalinated water flowing continuously or increase the heat tracing. III. Environmental protection aspects: The pipelines for receiving wastewater and ensuring its discharge in compliance with standards – add steam tracing; for underground pipes, it is recommended to lay them below the permafrost layer.