Regenerator Fuel and Oxygen Nozzle Elevation for Heat Distribution
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Solution Overview
Problem
In fluidized catalyst regeneration processes, such as paraffin dehydrogenation and fluid catalytic cracking, insufficient heat from coke combustion can hinder endothermic reactions, leading to reduced olefin production, and the introduction of supplemental fuel can cause hot spots and thermal damage due to inadequate mixing of fuel gas and air with the catalyst.
Innovation Solution
The process involves distributing oxygen and fuel gas streams through nozzles in the catalyst regenerator to ensure thorough mixing and consistent combustion, with the fuel gas and oxygen jets having the same elevation to promote efficient heat transfer and minimize hot spots, thereby regenerating the catalyst effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If supplemental fuel gas is added to the regenerator to provide sufficient heat for endothermic reactions, then heat availability for dehydrogenation is improved, but hot spots and thermal damage can occur due to insufficient mixing and heat dispersion
Solution Approach 1:
The fuel gas distribution system is segmented into multiple nozzles positioned at different locations and elevations within the regenerator. This segmentation allows the fuel gas to be introduced at multiple points, distributing the heat generation throughout the catalyst bed rather than concentrating it at a single location, thereby preventing hot spots while maintaining sufficient overall heat availability for endothermic reactions.
Solution Approach 2:
The invention applies local quality by positioning fuel gas nozzles at specific elevations and locations where they can effectively mix with air and catalyst in different zones of the regenerator. Each nozzle location is optimized to address local mixing requirements and heat distribution needs, ensuring that fuel combustion occurs in regions with adequate catalyst contact for heat dispersion while maintaining overall thermal balance.
2Device complexity
If fuel gas and air are not thoroughly mixed with catalyst, then equipment complexity is reduced, but incomplete combustion occurs leading to afterburn and excessively high temperatures downstream
Solution Approach 1:
The invention implements preliminary action by pre-positioning fuel gas nozzles within the regenerator structure and configuring them to introduce fuel gas at optimal locations before the main combustion zone. This preliminary introduction of fuel gas allows it to mix with air and catalyst in advance, ensuring complete combustion occurs within the regenerator rather than downstream, thereby preventing afterburn without requiring complex external mixing systems.
3Power
If fuel gas is combusted with insufficient catalyst contact, then combustion efficiency is improved, but excessively high temperatures cause thermal damage to catalyst and equipment
Solution Approach 1:
The invention merges the fuel gas combustion process with the catalyst bed by introducing fuel gas directly into regions where catalyst is present and circulating. This merging ensures that fuel combustion occurs in intimate contact with catalyst particles, which act as a heat sink to absorb and disperse combustion heat. The combination of fuel gas, air, and catalyst in the same zones enables efficient combustion while the catalyst prevents excessive temperature rise that would cause thermal damage.
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 approach ensures complete combustion of coke and supplemental fuel, providing sufficient heat for endothermic reactions while preventing thermal damage to the catalyst and equipment, thereby enhancing olefin production and process safety.
Implementation Method 1
combusting the fuel gas stream and carbon on the spent catalyst with the oxygen gas stream to provide flue gas and regenerated catalyst
Implementation Method 2
the oxygen gas jet generated from said oxygen nozzle and a fuel gas jet generated from said fuel gas nozzle have the same elevation in the regenerator... ensures complete combustion of the supplemental fuel gas and good heat transfer between vapor and catalyst
Data Source
AI summary
An oxygen gas stream is distributed to a spent catalyst stream through an oxygen nozzle of an oxygen gas distributor and a fuel gas stream is distributed to the spent catalyst stream through a fuel nozzle of a fuel gas distributor. An oxygen gas jet generated from said oxygen nozzle and a fuel gas jet generated from said fuel gas nozzle have the same elevation in the regenerator. In a regenerator, an oxygen gas distributor and a fuel gas distributor may be located in a mixing chamber. A fuel outlet of a fuel nozzle of the fuel gas distributor may be within a fifth of the height of the mixing chamber from an oxygen outlet of an oxygen nozzle of the oxygen gas distributor. In addition, clear space is provided between a fuel gas nozzle on a fuel gas distributor and a closest oxygen nozzle on an oxygen gas distributor.