Water replenishment issue in water ring vacuum pumps
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Guys, our company has over a dozen water ring vacuum pumps. Before, it was sufficient to fill the water tank before starting the pumps, but now we need to keep refilling it continuously; otherwise, the vacuum level will be affected. Our company is engaged in the production of amino acids. Now there is a demand to save water and energy; it is desired to reduce or eliminate the water supply to the vacuum pump. Previously, raw tap water was used as make-up water; I think it was the scale that caused poor heat exchange efficiency. To avoid the need for make-up water, it’s necessary to remove the scale first and then switch to DIW. I hope those with more experience can offer some advice :(
It seems that the issue of water replenishment in your water ring vacuum pump is indeed caused by scale, which leads to a decrease in heat exchange efficiency. Scale in vacuum pump systems can affect heat exchange efficiency, thereby impacting the level of vacuum. Here are a few suggestions: 1. **Descaling**: It is essential to carry out thorough descaling first. Chemical cleaning methods can be used to remove scale from the system. Make sure to choose a cleaning agent that is safe for the material of the equipment, to avoid damaging it. After cleaning, rinse thoroughly to avoid residual chemicals. 2. **Use DIW (deionized water)**: Switching to DIW can effectively reduce the formation of scale, as deionized water does not contain minerals that can cause scale to form. This is very helpful for maintaining the long-term operational efficiency of the equipment. 3. **Recycling cooling water**: Consider establishing a closed-loop water system to recycle cooling water. This not only saves water resources but also reduces the need for water replenishment. Water treatment facilities such as filters and water softeners can also be considered for inclusion in the circulation system to maintain water quality. 4. **Regular maintenance**: Even after switching to a DIW, it is still important to carry out regular maintenance and inspections on the water ring vacuum pump. This includes checking for leaks, inspecting and replacing damaged parts, as well as regular cleaning. 5. **Technical consultation**: It may also be necessary to consult the equipment manufacturer or a professional water treatment company to develop more detailed and specialized solutions tailored to your specific circumstances. Through the above measures, the problem of water replenishment can be effectively resolved, while also achieving the goals of water and energy conservation. I hope these suggestions can help you! .
The gas drawn in by the liquid ring pump is at a certain temperature, and due to its high-speed rotation, the pump itself generates heat. The combination of high temperature and high vacuum causes the liquid to vaporize, thereby preventing the vacuum from being maintained; moreover, cavitation damages the pump as well. A heat exchanger will be installed in the liquid ring circuit to cool it using cooling water. The liquid ring should use pure water or a liquid compatible with the chemicals in the system being pumped. If tap water is used, scale is formed during the vaporization process. At the same time, the liquid inside the liquid ring needs to be replaced from time to time, or it must be continuously drained, as the liquid carried in by gases affects the sealing performance. Here are a few suggestions: 1. For the heat exchanger, using small plates is sufficient; this reduces costs and makes cleaning on-site faster – one just needs to use a high-pressure water gun to clean the plates. 2. If there is a tank containing liquid inside the liquid ring, try adding chemicals or scale inhibitors and running the system in circulation to see if this improves the situation. 3. Increasing the flow rate of the cooling water in the heat exchanger can enhance the cooling capacity. 4. Before the vacuum system reaches the liquid ring pump, there is usually a gas-liquid separation tank or heat exchanger; try increasing the cooling capacity so that less material is drawn into the liquid ring pump. 5. The water ring pumps are connected in parallel; several connections are made to the vacuum pipeline, allowing the water ring pumps on lines that are not in use to temporarily assist in vacuum creation.
This post was last edited by Suibing on 2024-2-26 at 11:29. The original poster has provided a thorough analysis based on practical experience: the reduced efficiency of the existing heat exchanger leads to higher temperatures of the working fluid, which in turn affects the vacuum level of the water ring pump. I’m not too in favor of using plate exchangers as suggested upstairs. Plate exchangers are efficient, but cleaning them is troublesome due to the need to disassemble and reassemble them; moreover, their small channels are not suitable for this type of water quality. Plus, with a dozen or so water ring pumps, it’s not something that can be fixed simply by replacing small components; instead, shell-and-tube heat exchangers are easier to disassemble, assemble, and clean. With the heat exchanger currently partially malfunctioning, it is necessary to remove scale first or replace it with a new one
Water is added to the system from the water storage tank, and water is discharged through the overflow port on that same tank. According to the supervisor, this pump did not require continuous water replenishment in the past; it was sufficient to fill the water storage tank before starting up the system. But now it’s necessary to keep replenishing water. Apparently, the heat exchange efficiency is poor, and the heat cannot be removed; is it a problem with the heat exchanger or with the quality of the water? The pump is of the NASH 2BE1 model
If rehydration is effective, it means that the temperature of the water used for rehydration is lower than the water temperature in the circulation system. The purpose of your water replenishment has now become replacement. The current location for water replenishment does not yield a direct enough effect; it can be changed to the pipeline between the hot-side outlet of the heat exchanger and the pump’s water inlet.
What should I do if I don’t want to rehydrate?
The decrease in vacuum level still requires addressing the issue of scale; I have a good solution, and we can discuss it.
Just disassemble the heat exchanger and clean it. There is no need to replace the cooling water either; regular cleaning of the heat exchanger will be sufficient in the future
It improves the heat exchange efficiency; once the temperature of the working fluid drops after cooling, there is no need to add water.
1. First, add a descaling agent to the water storage tank to remove the existing scale. During this period, timely water replacement is carried out based on the water quality in the storage tank, but the stripping agent needs to remain in the system for more than 24 hours. 2. Check for scaling in the cooler; cleaning a plate-type cooler can easily lead to poor sealing and leakage. It is recommended to replace the cooler with a tubular heat exchanger that has a larger heat exchange area than the original one in order to reduce the temperature.