摘要 |
The hydrogenation of low rank coal to produce hydrocarbon liquids and gases is conducted in a first stage reaction zone at elevated temperature and pressure and without catalyst, followed by further hydrogenation of the total effluent in a second stage ebullated bed catalytic reaction zone which is maintained at slightly lower temperature. The first stage may comprise an ebullated bed of high density non-catalytic contact material. However, the presence of such contact material is not required. Clarified hydrocarbon liquid streams are returned to the first stage reaction zone as the slurrying oil and to the second stage zone as recycle oil to maintain a significantly higher percentage of unconverted coal solids in the first stage reaction zone than in the second stage zone. This two stage reaction arrangement produces a high percentage conversion of the low rank coal to liquid and gaseous products with good process operability. |