Sorbents for removing solid particles from crude oil
The invention relates to removing contaminants from oil using solid sorbents that are comprised primarily of carbon and preferably of coke particles. The coke particles have an affinity for contaminants in oil and are sized to be filtered from oil without plugging. Most contaminants have such a small size that they tend to plug up filters. As the contaminants agglomerate onto the solid sorbent, the resulting particles form a filter cake on conventional filter materials in such a way as to allow the oil to pass on through without significant pressure drop or delay.
1. A process for removing solid contaminants from crude oil comprising:
a) adding a solid sorbent to crude oil wherein the solid sorbent is a mixture of green coke and recycled green coke that has been subjected to an inert heating process to liberate/pyrolize at least a portion of the contaminants from a previous contaminant adsorption process;
b) agglomerating/adsorbing solid contaminants from the crude oil to the solid sorbent;
c) separating the solid sorbent with agglomerated/adsorbed solid contaminants from the crude oil;
d) separating undersized solid sorbent particles separated from the crude oil prior to recycling such solid sorbent so as to maintain a desired particle size for the solid sorbent used in the contaminant removal process; and
e) heating the solid sorbent to liberate/pyrolize the contaminants from the solid sorbent and to prepare the solid sorbent for recycling and re-use as solid sorbent in step a).
2. The process according to claim 1 wherein the green coke and recycled green coke has an average size of between 1 and 250 microns.
3. The process according to claim 1 wherein the green coke and recycled green coke has an average size of between 3 and 50 microns.
4. The process according to claim 1 wherein the mixture of green coke and recycled green coke has an average size of between 3 and 25 microns.
5. The process according to claim 1 further including a step of de-wetting the solid sorbent with contaminants agglomerated thereon so as to remove any residual crude oil from the solid sorbent.
6. The process according to claim 1 wherein the sorbent is selected to have a density of between 0.5 g/cc and 7 g/cc.
7. The process according to claim 1 wherein the sorbent is selected to have a density of between 0.7 g/cc and 2.0 g/cc.
8. The process according to claim 1 wherein the sorbent is selected to be at least partially hydrocarbon materials that contain a residual carbon content of at least 40%.
9. The process according to claim 1 wherein the sorbent is selected to be at least partially hydrocarbon materials that contain a residual carbon content of between 75% and 99%.
10. The process according to claim 1 wherein the sorbent is selected to be at least partially hydrocarbon materials that contain a residual carbon content of between 85% and 98%.
11. The process according to claim 1 wherein the separation of the sorbent from the crude oil occurs in a generally vertical tank with a crude oil feed and solid sorbent delivered to the top and mixed by a bladed stirrer attached to a generally vertical shaft that is rotated to stir the crude oil and solid sorbent mixture in the vessel and further wherein a filter is arranged generally horizontally such that the solid sorbent is exits adjacent the filter and the crude oil exits below the horizontal filter.