Claims
- 1. A process for recovering clarified, de-ashed, dried oil from wet used lubricating oil containing undesirable components, comprising the steps of
- (a) supplying used lubricating oil containing moisture and ash-forming contaminants to a drying zone at a temperature sufficiently high that moisture in said oil flashes off to form a dried oil;
- (b) feeding said dried oil to one or more heat treating zones wherein said dried used oil is heated to a temperature of at least about 600.degree. F. with agitation for a retention time within the range from about 2-5 hours to cause solids in said oil to become separable from the oil;
- (c) cooling said heat-treated oil to form a cooled oil; and
- (d) recycling up to 30 wt % of said cooled oil to said one or more heat treating zones and separating solids from the remaining cooled oil to produce a clarified, dried lubricating oil exhibiting an ash content of less than 0.01%.
- 2. The process of claim 1, wherein said process is continuous.
- 3. The process of claim 1, wherein the temperature of said drying zone is in the range of from about 250.degree. F. to about 300.degree. F.
- 4. The process of claim 3, wherein said temperature is about 275.degree. F. to 285.degree. F.
- 5. The process of claim 1, wherein said used lubricating oil has a moisture content of about 6%-8% by weight.
- 6. The process of claim 1, wherein the step of separating solids from the cooled oil of step (c) comprises filtering said cooled oil through a filter cloth coated with diatomaceous earth.
- 7. The process of claim 1 further comprising
- recirculating a portion of said dried oil for mixture with said used lubricating oil fed into said driving zone.
- 8. The process of claim 1 further comprising
- recirculating a portion of said cooled oil for mixture with said used lubricating oil fed into said drying zone.
- 9. A process for recovering clarified, de-ashed, dried oil from wet used lubricating oil that contains undesirable components, comprising the steps of
- (a) injecting a supply of wet used lubricating oil comprising (i) wet used oil, (ii) up to 30% of a recycle portion of the cooled oil from step (f) below, and (iii) a recirculating portion of dried used oil from step (a), into a drying zone, said recirculating portion (iii) being in sufficient quantity and at a sufficiently high temperature that moisture in said supply of used oil feed flashes off in said drying zone and dried used oil is withdrawn from said drying zone; then
- (b) heating the said dried oil to a temperature of at least 650.degree. F.; then
- (c) transferring said heated used oil to a heat treating and agitating zone;
- (d) agitating and flowing said heated dried used oil into successive areas of said heat-treating zone for a residence time within the range of 1-5 hours to permit solid particles to become more readily separable from said oil upon filtration;
- (e) removing the heat-treated oil from said heat-treating zone;
- (f) cooling the heat-treated oil of step (e) to about 240.degree. F. to about 280.degree. F. to form a cooled oil;
- (g) separating up to about 30 wt % of said cooled oil for recycle to a heating zone;
- (h) separating the solids from the remaining product of step (f) to produce a clarified, de-ashed dried oil, and
- (i) recovering said clarified, de-ashed dried oil at an ash content of <0.01%.
- 10. A process in accordance with claim 9, wherein said process is a continuous process.
- 11. A process in accordance with claim 10, wherein the temperature of said used oil in said drying zone is in the range from about 250.degree. F. to about 300.degree. F.
- 12. A process in accordance with claim 11, wherein said supply of oil to said drying zone is at a temperature in the range of about 250.degree. F. to 300.degree. F.
- 13. The process of claim 12, wherein said clarified, de-ashed, dried oil has an ash content of less than 0.001% by weight.
- 14. The process of claim 13, wherein the step of separating solids from the cooled oil of step (c) comprises filtering said cooled oil through a filter cloth coated with diatomaceous earth.
- 15. A process for recovering clarified, de-ashed, dried oil from wet used lubricating oil comprising the steps of
- (a) supplying a heated, wet used lubricating oil that contains undesirable components, said used oil comprising a mixture of said wet used oil and the recycle portion from step (d), below, to a drying zone wherein the temperature of said used oil supplied to said zone is such that moisture flashes off and is withdrawn from said zone;
- (b) transferring said dried used oil of step (a) to a heat treating and agitating zone wherein said dried oil is maintained at a temperature of at least about 600.degree. F. and kept in an agitated state;
- (c) removing heat-treated oil from said heat-treating and agitating zone and cooling it;
- (d) separating up to 50 wt % of said cooled heat-treated oil as a recycle portion;
- (e) mixing said recycle portion with wet used lubricating oil to form the used oil supply for step (a) above; and
- (f) separating solids from the remaining cooled product of step (c) to produce a clarified, de-ashed, dried oil with an ash content of <0.01%.
- 16. The process of claim 15, wherein the process is continuous.
- 17. The process of claim 15, wherein the used wet oil in said drying zone is at a temperature in the range of from about 250.degree. F. to about 300.degree. F.
- 18. The process of claim 17, wherein said used wet oil in said drying zone is at a temperature of about 275.degree. F. to 285.degree. F.
- 19. The process of claim 15, wherein said recycle portion comprises about 10% to about 30% by weight of said cooled heat-treated oil.
- 20. The process of claim 19, wherein said wet used lubricating oil has a moisture content of about 5%-10% by weight.
- 21. A process for recovering clarified, de-ashed, dried oil from wet used lubricating oil containing undesirable components, comprising the steps of
- (a) supplying a used wet lubricating oil to the first of one or more heat-treating areas wherein the temperature in said first area is such that moisture in said wet used oil flashes off in said first area;
- (b) heating the remaining dried oil to an elevated temperature of at least about 650.degree. F. with agitation;
- (c) agitating and flowing said heated dried used oil into successive areas of said heat-treating zone for a residence time sufficient to permit solid particles to become more readily separable from said oil;
- (d) removing the heat-treated oil from said heat-treating zone;
- (e) cooling the heat-treated oil of step (d) to about 240.degree. F. to about 280.degree. F. to form a cooled oil;
- (f) separating the cooled oil into a recycle portion of up to about 50 wt % and a remaining portion;
- (g) passing said recycle portion into admixture with said used wet lubricating oil supplied to step (a);
- (f) filtering said remaining portion through a filter cloth coating with diatomaceous earth; and
- (g) recovering a clarified, de-ashed, dried oil filtrate with an ash content of <0.01%.
Parent Case Info
This application claims benefit of Provisional Application No. 60/032,344 filed Dec. 4, 1996.
US Referenced Citations (20)