Dewaxing and wax filterability by reducing scraper speed in scraped surface chilling units
US4334978A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 24, 1980 |
| Grant date | Jun 15, 1982 |
| Priority date | — |
| Expiry date | Nov 24, 2000 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC10G73/08
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
In hydrocarbon oil dewaxing processes comprising passing the waxy oil through a staged vertical tower, injecting cold solvent at a plurality of stages along the vertical tower under conditions of high agitation to achieve substantially instantaneous mixing at each point, continuing the chilling, preferably at a rate of from 1.degree. to 8.degree. F. per minute, by means of cold solvent injection until a temperature at least 30.degree. F. above the filtering temperature but less than about 40.degree. to 45.degree. F. above the filtering temperature is reached and completing the cooling of the oil to the separation temperature in rotating element scraped surface chillers, the improvement comprising operating the scraped surface chillers at a chilling temperature range of at least 30.degree. F. while reducing the operating speed of the rotating elements in the scraped surface chiller to a speed of from 5 to 20% preferably 8 to 14% of the original design operation speed. Operation at this reduced speed improves wax separation rates by about 10 to 20% while not adversely effecting the heat transfer performance of the chillers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.