Use of quench water filters
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Should the chill water filters be used together as a pair, or should they be switched regularly? What is the interval for such switching?
The system is designed with two options so that you can switch between them; it’s best not to use both at the same time. There is generally no fixed rule for the switching cycle; it is determined mainly based on the quality of the graywater and its scaling rate.
Under normal circumstances, one unit is in operation while the other is in standby, and the switching is carried out based on the pressure difference before and after the filter during operation. Here, we usually switch at around 500 KPa.
This post was last edited by jensse on 2015-9-12 at 12:09. We never remove them; we keep both in use while driving, and after 60–80 days we take them out and clean them thoroughly.
We also check the pressure difference, but once it took us over ten days while driving before we realized that the valve at the base of the pressure difference gauge wasn’t open{:3_46:}
In practice, both are used; the other isn’t good for backup as deposits will form
For gasifiers of high pressure grades, it is difficult to have backups, and the inlet and outlet valves of the filters become hard to operate after long-term use
Many factories encounter the problem of filters not being available as backups, primarily due to the deposition of ash in the quench water, which causes blockages at the inlet and outlet when switching filters. This issue is especially apparent in the pipes downstream of the filter outlet shut-off valves; as a result, many factories use two filters simultaneously. My personal opinion: 1. When installing the pipeline, place the inlet and outlet shut-off valves of the filter as close as possible to the main chilled water pipe in order to prevent the accumulation of ash; however, this will reduce the stress at the pipeline branches. 2. Keep the drain valve of the filter slightly open to prevent long-term accumulation of ash, but this will increase wear on the drain valve, leading to potential leaks over time. Feel free to give feedback
The selection of which filter to use is determined based on the quality of the graywater. Scaling and clogging are two different concepts. When the system uses two filters, the flow rate through each individual filter decreases, which makes it easier for calcium and magnesium salts to precipitate and cause scaling; this also affects the operation cycle. When only one filter is in use, the manual valve used to switch to the backup filter may not open due to stress from the handle movement as well as scaling caused by fine particles. Therefore, it is recommended to add flushing water before and after the ball valves connected to the filters, while ensuring that the structural stress in the cooling water pipelines is not compromised. One-inch small pipes can be used for the piping.
When switching between different chill water filters, it is necessary to take into account the tendency of water quality to form scale. In the pipes, the temperature of the chill water remains constant and it is in a flowing state, so the scale that forms has little impact on the pipes. However, when the cold water from the switched filter enters the quenching water pipeline, scale deposits form rapidly inside the subsequent quenching water pipes and peel off from them, causing blockages. There are significant risks when switching the device
Now, many designs use a single filter, with its size increased to extend the service life; it is generally cleaned in accordance with the operating cycle of the furnace.