Method to mitigate fouling of a vacuum wash bed

Abstract

Fluid medium such as light cycle oil, water, FCC slurry and decanted oil, improve this method for vacuum distillation of a petroleum product. The method may be used in the petroleum refining industry for fractionating of petroleum base stock in a vacuum column. The fluid medium prevents the formation of thermoset polymers and the resultant fouling of the wash beds in the vacuum column.

We claim: 
     
         1 . A method of preventing build up, fouling, and hardening of thermoset polymers in a vacuum distillation column wash bed, wherein the introduction of feedstock is removed from the wash bed and the wash bed is allowed to cool down from peak operating temperatures, comprising the steps of:
 delivering a fluid medium to the wash bed to maintain the wash bed temperature at or above 350° Fahrenheit;   wherein the maintenance of the wash bed temperature at or above 350° Fahrenheit prevents the solidification of any polymers that accumulate in the wash bed during normal operations, thus, preventing the polymers from hardening into a permanent foulant in the wash bed; and   removing the polymers from the wash bed and vacuum distillation column.   
     
     
         2 . The method according to  claim 1  wherein the fluid medium is continuously delivered to the wash bed during fractionating. 
     
     
         3 . The method of  claim 1  wherein the fluid medium is steam that is injected and transferred up through the vacuum wash beds. 
     
     
         4 . The method of  claim 1  wherein the fluid medium is slurry residuals having aromatics with solvent properties for dissolving entrained heavy hydrocarbons and transferring the hydrocarbons from the wash bed and fluid column. 
     
     
         5 . The method of  claim 1  wherein the fluid medium is continuously delivered to the wash beds to maintain the soft polymers and prevent the soft polymers from hardening into a permanent foulant in the wash bed.