On the influence of the properties of solvent deasphalting feedstocks on operations
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Our leaching unit is a device that uses reduced-pressure residue as raw material and propane as solvent to produce deasphalted oil for use as a catalyst feedstock. Dear experts in the leaching unit, what impact does the high or low carbon residue content of vacuum residue have (whether it is on the lighter or heavier side) on the operation of the leaching unit? What is the impact on product quality? How can atmospheric and vacuum distillation provide high-quality raw materials for leaching when the product quality is satisfactory? Thank you!
Generally speaking, solvent deasphalting units do not have high requirements regarding the raw material; changes in the properties of the raw material (such as the residue you mentioned) have little impact on operation. However, changes in the composition of the raw material (variations in density) have a significant effect on the operation of the unit! If the saturated phenol content of the feedstock increases (in other words, it becomes lighter), then the yield of light oil from the solvent deasphalting unit will increase! Generally, it is difficult to require a vacuum distillation unit to control the feedstock; changes in the properties of vacuum residue are usually caused by changes in the properties of the crude oil. Unless there are changes in the production process conditions, the properties of vacuum residue remain relatively stable during periods of steady operation in such units! In general solvent deasphalting units, the feedstock does not need to have any residue content; there are no requirements whatsoever with regard to this! Apart from the process conditions, it is the original basic properties (the four components) that affect the yield and product properties
The main indicator for oil removal is residual carbon, which ensures long-term operation of the catalytic unit. If there are short-term changes in the properties of the raw material, no adjustments are made, as both the extraction temperature and the solvent ratio have a certain degree of flexibility in operation. However, if the properties of the raw material change over an extended period, then both the extraction temperature and the solvent ratio need to be adjusted
If the residue carbon content is high, and no adjustments are made to the operation parameters, the carbon content in the oil-free product will also increase; conversely, it will decrease. The main approach is to adjust the extraction temperature – increasing it improves the selectivity of the solvent, reduces its solvency, which in turn lowers the yield of the oil-free product and decreases the carbon content. On the other hand, the solvent ratio generally does not need to be changed, as the properties of the raw materials do not change significantly under normal operating conditions.