Regarding the commissioning of the propane deasphalting unit
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Recently, our company has just completed its technical upgrades and is preparing to start up the propane deasphalting unit of the first production line. Two attempts have been made so far, and neither was successful. There are several issues: first, it’s difficult to maintain an appropriate level of the extraction liquid; second, too much water was detected in the refined oil; third, the refined oil is dark in color, which suggests a high level of residue. Our company mainly recycles used lubricating oil, internal combustion engine oil, and other types of oil; it produces base oils for lubricants as well as by-products such as gasoline, diesel, and asphalt. We use only a small facility with a capacity of 60,000 tons. But propane has been a bit problematic to use recently; I’m wondering if the experts have any good suggestions regarding the parameters. Currently, the pressure in our extraction tower is 87 degrees, with the pressure controlled at 4.2 MPA; the pressure in the supercritical tower is 102 degrees, also at 4.2 MPA
First, considering that the critical pressure of propane is 4.193 MPa and its critical temperature is 96.67°C, it is recommended that you consider lowering the extraction temperature slightly and increasing the extraction pressure. However, the principle for making adjustments should be to change only one parameter at a time, using small adjustments made multiple times； Second, improve the pretreatment of raw materials by removing excess mechanical impurities and moisture; it is recommended that the water content in the feed material be no more than 10PPM ； Third, it is clearly caused by a mixed phase; it is necessary to increase the solvent ratio, reduce the load on the equipment, and increase the temperature difference between the top and bottom of the extraction tower. For reference.
Is there no temperature gradient, with 87 degrees at both the top and bottom of the tower?
This post was last edited by Hu Yucheng on 2024-4-12 at 16:56. The ratios of the main solvent, secondary solvent, and supercritical solvent, as well as the feed temperature of the tower, the bottom temperature, and the top temperature – in other words, it’s necessary to use supercritical propane to create a temperature gradient in T-1. Since you don’t mention any of these details, how can one make any judgments?
This post was last edited by Hu Yucheng on 2024-4-12 at 16:56. There should be a temperature gradient, with the temperature at the top being higher than that at the bottom. Propane’s critical point is at 97 °C and 4.26 MPa; it’s just a little below this critical value