Cross-Flow Reactor for Hydroprocessing with Reduced Vaporization
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Solution Overview
Problem
Conventional three-phase reactors face issues such as high gas-to-oil ratios leading to vaporization of hydrocarbons, increased pressure drops, reduced hydrogen partial pressure, and inefficient catalyst utilization, resulting in non-selective cracking and high energy consumption during hydroprocessing of hydrocarbon feedstocks.
Innovation Solution
A cross-flow reactor design with a central gas distributor and packed catalyst bed, where reactant gas is distributed radially and hydrogen is introduced to maintain high partial pressure, reducing pressure drop and vaporization, and allowing for efficient hydroprocessing with multiple stages for improved reaction control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high gas to oil ratio is used in co-current down flow hydroprocessing, then hydrogenation reactions are enhanced, but vaporization of hydrocarbon feed increases and pressure drop across reactor increases
Solution Approach 1:
The patent inverts the conventional co-current down flow configuration by implementing a counter-current flow mode where gas and liquid reactants flow in opposite directions through the catalyst bed. This inversion allows gas to be introduced at the bottom and liquid at the top, preventing feed vaporization while maintaining high hydrogen partial pressure for effective hydrogenation reactions.
Solution Approach 2:
The patent changes the flow direction parameter from co-current to counter-current mode, and optimizes gas to liquid ratio parameters to achieve efficient mass transfer without excessive vaporization. The counter-current flow creates favorable partial pressure gradients that enhance hydrogen dissolution in the liquid phase without requiring high gas flow rates that would cause vaporization.
2Quantity of substance
If high gas to oil ratio is used, then hydrogen availability is improved, but pressure drop across the reactor increases
Solution Approach 1:
The counter-current flow configuration inverts the conventional approach by introducing gas at the bottom and liquid at the top. This creates a pressure gradient that favors hydrogen dissolution into the liquid phase without requiring high gas flow rates, thereby maintaining hydrogen partial pressure while minimizing pressure drop across the reactor.
3Ease of operation
If co-current reactor configuration is used, then操作简单 is simplified, but mean flow path for reactant gas increases leading to additional pressure drop
Solution Approach 1:
The patent inverts the flow configuration from co-current to counter-current mode. While counter-current operation requires slightly more complex control, it dramatically shortens the gas flow path length by allowing gas to travel upward against the liquid flow, reducing the mean flow path and associated pressure drop while improving mass transfer efficiency.
4Productivity
If conventional co-current down flow mode is used, then catalyst bed utilization is improved, but gas phase holdup increases continuously from reactor entrance to exit
Solution Approach 1:
The counter-current flow configuration inverts the conventional co-current mode, causing gas to flow upward from the bottom while liquid flows downward from the top. This creates a more uniform distribution of gas phase holdup throughout the catalyst bed, preventing the continuous increase from entrance to exit that occurs in co-current mode, thereby improving overall catalyst utilization.
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
The cross-flow reactor design minimizes feed vaporization, reduces pressure drop, and enhances reaction rates, achieving low severity operation and efficient hydroprocessing with reduced product inhibition and catalyst utilization, compared to conventional reactors.
Implementation Method 1
The at least one reactor stage has a central gas distributor having perforations on a lateral surface for distributing reactant gas into the cross-flow reactor
Implementation Method 2
In hydroprocessing, hydrogen react with hetero atoms to produce gases like hydrogen sulphide and ammonia, thereby removing the hetero atoms from the hydrocarbon feedstock
Implementation Method 3
hydrocarbon feedstock has to be hydroprocessed to a suitable quality for production of various petroleum products
Implementation Method 4
Gas-liquid-solid catalytic reactors, also called three-phase reactors, are widely used in various industries
Implementation Method 5
Hydroprocessing is a highly exothermic process involving treatment of hydrocarbon feedstock with hydrogen in the presence of a suitable catalyst
Data Source
AI summary
Methods, apparatus and processes for three phase contacting and reactions in a cross flow reactor with reduced feed vaporization, low pressure operation, higher liquid holdup, lower reactor pressure drop, low severity operation, and reduced product inhibitory effects. A cross flow reactor for three phase catalytic hydroprocessing, having at least one reactor stage is disclosed. The reactor stage has a central gas distributor with perforated lateral surface for distributing gas, a middle region accommodating a packed catalyst bed, and an outer gas space for removal of effluent gases from the middle region. The middle region receives a liquid reactant and gas from central gas distributor to carry out three phase catalytic hydroprocessing reaction.