Base oil is produced by vacuum distillation of used engine oil, with an unclear oil-water boundary
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I am currently using normal-pressure water removal; after that, the vacuum pump is activated step by step, and once the desired vacuum level and temperature are reached, the base oil is produced. The problem is that during normal-pressure water removal, as well as during the distillation of gasoline and diesel at around 210 degrees Celsius, the resulting oil still contains water. When the vacuum pump is activated step by step at 210 degrees Celsius, and a vacuum level of 0.8 KPA is achieved, light base oil begins to be produced. However, the oil obtained between 240 and 280 degrees Celsius still contains water. Water removal has become a persistent issue in this manufacturing process – it’s impossible to eliminate water completely. After refining the distilled oil with clay at 120 degrees Celsius and then cooling it, the oil becomes slightly turbid. With the same distilled oil, no turbidity occurs after filtration in the laboratory. We believe that in the laboratory environment, a larger amount of clay is used, and the filtering paper effectively absorbs water, allowing for thorough water removal and thus preventing turbidity. I seek advice on how to make the boundary between oil and water more distinct during the distillation process, in other words, how to reduce the water content in the distilled base oil
Based on what you’ve described, it should be intermittent distillation. Whether it is natural circulation or forced circulation, the temperature inside the reactor cannot be uniform. Without fully removing the moisture, heating is applied to produce the base oil; the moisture in the cooler areas of the reactor gradually vaporizes and comes out along with the base oil, which leads to the problem you mentioned. Suggestions: 1. Use negative pressure for dehydration, as this will reduce the dehydration time. Increase the vacuum level gradually depending on the water content, following the principle of avoiding boiling up inside the tank. 2. The moisture and the earlier-stage gasoline and diesel fractions are sent to a receiving tank, which facilitates the separation of oil from water ； The base oil goes into another receiving tank. 3. Dehydration requires sufficient time; the base oil cannot be heated before all the water has been removed, otherwise subsequent processing will become very complicated.
What is the dehydration method? Is it just simple constant-temperature dehydration?
Although you haven’t provided a detailed description of your dehydration process, I have a feeling that the problem lies in your process!
Our company wants to launch a project for recycling used engine oil into base oil; does anyone among you have any preliminary feasibility study materials that we could use to learn from?*
Is it being cooked in a large pot or through batch operation in a tower?
It mainly depends on the water content, gasoline content of your oil product, as well as the height of the distillation column, to ultimately determine the processing temperature of the reactor!
I’m almost done; solvent extraction is in progress
Where is your company located? Can we go take a look? Are you in a laboratory or do you have equipment available?