FCC Riser Distributor Tip Configuration for Coke Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The generation of coke on the riser wall in Fluid Catalytic Cracking (FCC) units leads to hydraulic imbalances and potential shutdowns, especially when processing heavier feeds, due to their higher coking tendencies.
Innovation Solution
Incorporating a riser with an enlarged lower section and positioning the feed distributor tip away from the wall, above the catalyst and steam introduction, to enhance catalyst mixing and reduce coke deposition, by using a feed distributor with multiple nozzles arranged around the enlarged section, injecting hydrocarbon and steam at specific velocities and angles to create a bubbling bed and prevent wall contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heavy feedstocks are processed in conventional FCC units, then higher coking tendencies occur, but riser coking increases leading to hydraulic imbalances and shutdowns
Solution Approach 1:
The riser geometry is modified by enlarging the lower section diameter, creating a dimensional change that provides additional space for catalyst-feed mixing. This dimensional modification prevents feed from contacting the riser wall, thereby eliminating the pathway for riser coking while maintaining heavy feedstock processing capability
Solution Approach 2:
Catalyst acts as an intermediary substance that is introduced below the feed injection point. The catalyst serves as a medium that mixes with the heavy feedstock in the enlarged lower section, preventing direct contact between feed and riser wall, thus eliminating coking while enabling processing of high Conradson carbon feeds
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration decreases riser coking, allowing for more efficient processing of heavy feedstocks by maintaining hydraulic balance and reducing coke accumulation on the riser walls, thereby extending operational periods and improving unit performance.
Implementation Method 1
a first section of the riser prior to or during introduction of the feed. Steam or an inert gas may be used to accelerate catalyst
Data Source
AI summary
An FCC process comprising an enlarged riser section and a distributor in an elevated position and with an opening in its tip away from riser walls may reduce coke build-up along the interior walls of a riser. Catalytic mixing may be improved, which could reduce riser coking by increasing hydrocarbon contact with catalyst before contacting the riser wall. Increasing the distance between the introduction of the hydrocarbon and the riser wall may increase this likelihood for hydrocarbon-catalyst contact. Highly contaminated hydrocarbons cause greater coking than do normal hydrocarbons and this FCC process may be effective in decreasing riser coking on such heavy hydrocarbons.