What kind of fluid is better in choosing hot oil pump mechanical seal’s flushing fluid and its reasons

The primary mode of operation of all ancillary facilities is flushing. As for which fluid to choose as the flushing fluid, it can be flexibly controlled according to specific conditions. This article talks about how to choose the flushing fluid of the hot oil pump mechanical seals.

The most typical units in hot oil pumps are atmospheric tower bottom pumps and vacuum tower bottom pumps in atmospheric and vacuum distillation units, and oil slurry pumps in catalytic cracking units.Their common features are that the temperature is as high as 360~370°C, that the medium contains impurities, and that the viscosity is high.These constitute one of the difficult problems of pump maintenance work in refineries. In order to change the working environment of the mechanical seal, injection flushing is often used (referring to the single mechanical seal).

So what fluid is used for flushing? Some factories use light diesel oil as flushing fluid. Although it is easy to obtain in refineries and has good other properties, it is a product after all, and it is not economical to mix it with the above-mentioned heavy oil.More importantly, it is easy to cause the pump to evacuate. As we all know, light diesel oil is a component at 170-360°C, more than 50% of the components vaporize at 270-300°C, and more than 90% of the components vaporize at about 350°C. Obviously, light diesel oil is not suitable as flushing fluid for the above-mentioned thermal oil pump.Using the raw material oil (wax oil) of the catalytic device as the flushing fluid overcomes the above-mentioned shortcomings, which not only reduces the production cost (wax oil is not a product), but also avoids pumping out. In order to reduce the viscosity of wax oil, its temperature can be controlled at about 100°C. Atmospheric pressure tower bottom pumps and vacuum tower bottom pumps can also use wax oil as flushing fluid if they use a single end face seals.

What kind of fluid is better for hot oil pump mechanical seal as flushing fluid? Do you know the answer after reading this article?