| abstract |
A process for cracking lignin-containing feed materials, such as precipitated from black liquor, to produce hydrocarbon products such as ethylene, utilizing dual fluidized beds of particulate solids in series flow arrangement. In the process, the feedstock is introduced with a diluent gas such as steam into the first or fast fluidized bed for cracking reactions at superficial gas velocity exceeding about 5 ft/sec. A particulate solids carrier material, which can comprise at least partly coke produced in the process, is circulated between the beds, and coke deposited on the carrier in the first or cracking bed at 1000 DEG -1600 DEG F. temperature is burned off in a second or combustion bed maintained at 1400 DEG -2000 DEG F. temperature by an oxygen-containing gas and diluent steam introduced therein. Superficial upward gas velocity in the fast fluidized bed zone exceeds about 5 ft/sec. and the bed density exceeds about 3 lb/cu.ft. If desired, some externally supplied particulate solids carrier material also can be used in the process. Also, supplemental fuel can be supplied to the slow bed combustion zone if needed to maintain the desired temperature therein. |