Upflow Reactor Gas Distributor for Hydrogenation Capacity
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Solution Overview
Problem
Upflow reactors used in hydroconversion of heavy oils have limited hydrogenation capacity due to low gas-liquid contact surface, which restricts the conversion of heavy oils to light hydrocarbons (350° C.−), and increasing this capacity without raising gas holdup is challenging.
Innovation Solution
Equipping the reactor with a gas distributor having at least 100 orifices per m2 and feeding hydrogen at a surface velocity that causes bubble packing, maximizing the gas-liquid unit surface without exceeding a gas holdup of 0.33, thereby increasing hydrogenation capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogen is fed by simple bubbling in conventional upflow reactors, then the reactor operation is simple, but the gas-liquid contact surface is low resulting in limited hydrogenation capacity
Solution Approach 1:
The gas distribution system is segmented into multiple distributors with numerous small orifices (at least 100 per m²) arranged in series along the reactor height. This segmentation of the hydrogen feed into many small streams creates extensive gas-liquid contact surface area while maintaining manageable system complexity through modular distributor units.
Solution Approach 2:
The solution transitions from simple bottom-fed bubbling to a multi-dimensional gas distribution approach where hydrogen is introduced at multiple heights and locations through series-arranged distributors. This spatial distribution across multiple dimensions maximizes contact surface area without proportionally increasing operational complexity.
2Productivity
If the gas holdup is raised to increase the specific gas-liquid surface, then the hydrogenation capacity increases, but the volume of reaction liquid in the reactor decreases reducing cracking capacity
Solution Approach 1:
Different regions of the reactor are assigned different functions: upper regions with gas distributors focus on hydrogenation (high gas-liquid contact), while lower regions maintain larger liquid volume for cracking reactions. This local differentiation allows simultaneous optimization of both hydrogenation capacity and cracking capacity without compromising either function.
Solution Approach 2:
The reactor is functionally segmented into zones with different gas holdup levels and liquid volumes. By distributing gas injection points throughout the reactor height rather than concentrating them at the bottom, the system creates localized hydrogenation zones without globally reducing the reaction liquid volume needed for cracking capacity.
3Productivity
If the specific gas-liquid surface is increased through high gas holdup, then the hydrogenation capacity increases, but the liquid filling of the reactor decreases
Solution Approach 1:
The gas distribution system utilizes the vertical dimension by placing multiple distributors at different heights along the reactor axis. This vertical distribution creates extensive gas-liquid contact surface area without requiring high gas holdup throughout the entire reactor volume, thereby preserving liquid filling while achieving high hydrogenation capacity.
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 allows for the complete hydroconversion of heavy oils to light hydrocarbons (350° C.−), resulting in a higher weight average hydrogen content in conversion products, suitable for petrochemical feedstocks, while maintaining optimal liquid filling and cracking capacity.
Implementation Method 1
increase the gas-liquid contact surface through which the hydrogen must diffuse in order to feed all the reactions that a hydroconversion process requires
Implementation Method 2
feeding hydrogen at a surface velocity such as to cause the packing of the gas bubbles, whatever density of orifices the gas distributor used has
Data Source
AI summary
Disclosed is a process in which the jump in hydrogenation capacity, necessary to hydroconvert heavy oils totally to light hydrocarbons (350° C.−), is obtained by using an upflow reactor equipped with a gas distributor having a high density of orifices, which is capable of causing the packing of the gas bubbles, this being the most advantageous fluid dynamic condition. The resulting conversion products are suitable as petrochemical feedstocks.