Process and apparatus for ethylene production
A thermal cracking process and apparatus are disclosed for economical manufacture of lower olefins and valuable coproducts by pyrolysis of liquid or gaseous hydrocarbon feedstocks ranging from ethane to tar sands particularly feedstocks, such as gas oil, naphtha, residual oils or tar sands. The pyrolysis unit is a riser reactor heated by hot agglomerated ash particles and designed for short residence time to minimize the time of contact of the feedstock with the hot ash. The agglomerated ash is continually produced in a fluidized bed combustion unit by burning particles of coal or other solid carbonaceous material, and the hot agglomerated ash is continually forced upwardly through the riser by superheated steam which is further superheated in the riser reactor and which serves as dilution steam for hydrocarbon partial pressure reduction. Additional dilution steam enters the reactor with the preheated feedstock. A water quench at the outlet of the reactor slows down or stops secondary reactions as the cracked gases are separated from the hot ash in a roughing cyclone separator. The ash particles, which are coated with coke or char after reaction, are preferably steam stripped to remove occluded hydrocarbon and are thereafter recycled to the bed of the combustion unit. If the feedstock is tar sand or a feedstock with high coking tendencies, it may be preferable to burn at least part of the char or coke coated ash and/or sand particles from the riser reactor in a separate burner and thus dispose of some of the solids before the ash recycle to the main combustion unit.
- Assignee:
- Arthur G. McKee and Co.
- Patent Number(s):
- US 4172857
- OSTI ID:
- 5390770
- Resource Relation:
- Patent File Date: Filed date 3 Apr 1978
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
03 NATURAL GAS
04 OIL SHALES AND TAR SANDS
ETHYLENE
PRODUCTION
EQUIPMENT
HYDROCARBONS
OIL SANDS
PETROLEUM
PROCESSING
THERMAL CRACKING
ALKENES
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
CRACKING
DECOMPOSITION
ENERGY SOURCES
FOSSIL FUELS
FUELS
ORGANIC COMPOUNDS
PYROLYSIS
THERMOCHEMICAL PROCESSES
020400* - Petroleum- Processing
030300 - Natural Gas- Drilling
Production
& Processing
040403 - Oil Shales & Tar Sands- Refining