Problems with loading liquefied petroleum gas and liquid ammonia
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The loading pumps for liquefied petroleum gas and liquid ammonia in our company are both centrifugal pumps. A problem has arisen: when the pressure difference between the spherical tank and the tank truck is low, the medium in the inlet pipeline vaporizes, causing cavitation in the centrifugal pump, and as a result the outlet pressure cannot be increased. How should this issue be addressed?
This is a common problem. Previously, we used magnetic pumps for unloading, and although they do not leak and are relatively safe, magnetic pumps belong to the category of centrifugal pumps. Although we try our best to minimize the resistance at the pump inlet through proper piping to avoid cavitation, it remains a complicated process, and cavitation can still occur if not handled carefully. So now we use compressors for liquefied petroleum gas and liquid ammonia to unload the cargo; it’s very convenient. The compressors for liquefied petroleum gas and liquid ammonia are not expensive, and there are several manufacturers in Bengbu, Anhui that produce them – you can go and ask about them. What I mentioned above refers to unloading; the same principle applies to loading, where a compressor can also be used.
We use shielded centrifugal pumps for loading liquefied gas, and we have not encountered the issue mentioned by the original poster; everything is working normally
This post was last edited by hcs9138 on 2011-1-9 at 10:11. OP, what is your process for loading the vehicles? Before loading, we require pressure balance in the gas phase of the tank truck and the spherical tank, and the loading rate (pressure) is controlled through the pump outlet valve. So, the fact that the pressure in the spherical tanks and tank trucks mentioned by the original poster is similar likely isn’t the main cause of cavitation; rather, it’s probably an inappropriate choice of pump – the pump selected may not be suitable for liquefied gas and liquid ammonia
What is your process for loading the goods onto the vehicle? ----------------------- New men’s winter clothing on Taobao.com; women’s clothing in Taobao.com’s store; women’s clothing for summer 2010 on Taobao.com; women’s winter clothing on Taobao.com
The loading process involves connecting the gas and liquid phase lines; first, the gas phase valve is opened to achieve pressure equilibrium between the spherical tank and the tank truck, after which the liquid phase valve is opened. The loading pump room is located quite far from the loading station, about 1500 meters away. It’s easier to start the pump when the weather is cooler; however, it’s difficult to do so when the temperature is high (the outlet pressure doesn’t rise). It seems that there’s a lot of air in the pipelines, which prevents them from being emptied properly and prevents the pump from being filled fully. Is it maybe a problem with choosing the centrifugal pump? Could a compressor solve this problem?