Liquid Phase Hydroprocessing Reactor Temperature Management
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Solution Overview
Problem
Conventional hydroprocessing systems require large amounts of excess hydrogen gas to maintain the continuous gas phase in trickle-bed reactors, leading to increased complexity, capital, and operating costs, as well as temperature management challenges, especially in reactions with high heat release, which can exceed acceptable limits for catalysts.
Innovation Solution
A hydroprocessing reaction zone system that operates in a substantially liquid phase with internal heat transfer sections to manage temperatures without recycle gas or additional quench streams, using dissolved hydrogen and multiple catalyst beds with integrated heat transfer to maintain optimal temperatures and reduce hydrogen consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If large amounts of excess hydrogen gas are used to maintain continuous gas phase in trickle-bed reactors, then hydroprocessing reactions can proceed, but system complexity, capital cost, and operating cost increase significantly
Solution Approach 1:
The invention changes the phase parameter of the reaction medium from gas-phase (trickle-bed) to liquid-phase continuous system. This fundamental parameter change eliminates the need for large amounts of hydrogen gas to maintain continuous phase, thereby reducing system complexity while maintaining hydroprocessing efficiency
Solution Approach 2:
The invention transitions from a gas-based system (pneumatic) to a liquid-based continuous system (hydraulic). The liquid continuous phase carries dissolved hydrogen and reactants through the reactor, eliminating the need for high-pressure gas circulation systems and associated compressors
2Quantity of substance
If high-pressure recycle gas compressors are used to recycle hydrogen, then hydrogen supply is maintained, but capital cost and operating cost increase by 15-30 percent
Solution Approach 1:
The invention extracts and eliminates the high-pressure recycle gas compressor from the system by transitioning to a liquid-phase continuous system. Hydrogen is supplied dissolved in the liquid phase, removing the need for mechanical compression equipment and associated costs
Solution Approach 2:
The invention replaces the mechanical compression system with a chemical dissolution system. Instead of mechanically compressing and recycling hydrogen gas, the system uses hydrogen dissolved in the liquid continuous phase, substituting mechanical energy with chemical transport
3Productivity
If exothermic reactions are conducted in hydroprocessing, then desired chemical transformations occur, but temperature increases can exceed catalyst operating limits
Solution Approach 1:
The invention introduces a liquid continuous phase as an intermediary heat transfer medium. This liquid phase absorbs excess reaction heat and carries it away from the catalyst particles, acting as a thermal mediator that prevents temperature runaway while maintaining high reaction rates
Solution Approach 2:
The invention utilizes the high heat capacity and phase stability of the liquid continuous phase to manage reaction temperatures. The liquid phase absorbs thermal energy without significant temperature increase, leveraging phase transition properties to control exothermic reactions
4Ease of manufacture
If two-phase hydroprocessing systems are used to eliminate recycle gas compressors, then capital costs are reduced, but temperature management becomes more difficult
Solution Approach 1:
The liquid continuous phase performs multiple functions simultaneously: it serves as the reaction medium, hydrogen carrier, and heat transfer fluid. This multi-functionality simplifies temperature management while maintaining the capital cost benefits of eliminating recycle gas compressors
Solution Approach 2:
The continuous liquid phase provides continuous heat removal throughout the reactor volume, unlike batch or intermittent cooling methods. This continuous thermal management action makes temperature control more easier while maintaining the simplified two-phase system architecture
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 effective temperature control within the reaction zone, reduces the need for costly recycle gas compressors, and maintains catalyst efficiency by avoiding dilution with external fluids, resulting in a more compact and simplified hydroprocessing system with improved separation of effluent phases.
Implementation Method 1
The temperatures of the process flow through the reaction zone are managed by at least one internal heat transfer section positioned within the reaction vessel
Implementation Method 2
a liquid-phase reaction zone is provided wherein the liquid phase includes an amount of dissolved hydrogen
Data Source
AI summary
A method of hydroprocessing hydrocarbons is provided using a substantially liquid-phase reactor having first and second catalyst beds with a heat transfer section positioned therebetween. The first and second catalyst beds and the heat transfer section are combined within the same reactor vessel. Each catalyst bed having an inlet temperature and an exit temperature and having a hydroprocessing catalyst therein with a maximum operating temperature range. The method hydroprocesses the hydrocarbons and removes sufficient heat from the hydrocarbons using the heat transfer section so that the exit temperature of the hydrocarbons existing the first catalyst bed is substantially maintained below the maximum operating temperature range of the hydroprocessing catalysts in the first bed and, at the same time, also providing the hydrocarbons to the second catalyst bed at the inlet temperature so that the exit temperature of the hydrocarbons at the exit of the second catalyst bed also does not exceed the maximum operating temperature range of the hydroprocessing catalyst in the second bed.