Process for in situ oil shale retorting with off gas recycling
US3994343A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 4, 1974 |
| Grant date | Nov 30, 1976 |
| Priority date | — |
| Expiry date | Mar 4, 1994 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S208/951
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
This process is suitable for in situ retorting of oil shale particles, with retorting proceeding downwardly through a bed of broken pieces of shale. When a single bed is being retorted, air is passed downwardly after ignition until a hot zone trailing the combustion zone has built up to some predetermined thickness, for example, 20 feet having a temperature over 1000.degree. F. Thereafter off gas from the bed is recycled downwardly without air. Reaction of the recycle gas with the heated spent shale increases the heating value of the resultant off gas. The transfer of heat without combustion increases the yield of oil. When the maximum temperature in the bed drops to a predetermined temperature above the self-ignition temperature of the shale, air is again introduced to reestablish a combustion zone and build up a hot zone. Retorting continues with alternating combustion and recycling periods through the entire bed. When multiple beds of oil shale particles are retorted air is passed downwardly through one of the beds to maintain a combustion zone until a sufficient hot zone trailing the combustion zone has been produced. Air is then passed through a second bed of oil shale particl…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.