Liquid-Phase Hydroprocessing System Dissolved Hydrogen Delivery
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Solution Overview
Problem
Existing hydroprocessing methods face limitations due to hydrogen diffusion constraints, leading to rate-limited reactions and increased hydrogen demand, particularly in liquid-phase systems where hydrogen depletion occurs, restricting conversion rates and requiring complex reactor systems.
Innovation Solution
The method involves a liquid-phase hydroprocessing system where a hydrocarbon feed stock is combined with a previously hydroprocessed liquid-phase stream enriched with hydrogen, allowing for increased dissolved hydrogen concentration and reduced hydrogen addition, maintaining a constant hydrogen level throughout the reactor by incorporating excess hydrogen in a small vapor phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If excess hydrogen gas is used in three-phase trickle-bed reactor, then hydrogen supply to catalyst is improved, but hydrogen consumption and reactor complexity increase
Solution Approach 1:
The patent transitions from a three-phase gas-liquid-solid system to a two-phase liquid-solid system by dissolving hydrogen in the liquid feed stream before it enters the reactor. This eliminates the need for excess gaseous hydrogen and the associated gas-liquid-solid three-phase complexity, while still providing adequate hydrogen supply to the catalyst through the liquid phase.
Solution Approach 2:
The patent uses hydraulic principles by saturating the liquid feed stream with hydrogen under pressure before injection into the reactor. This allows hydrogen to be transported and delivered to the catalyst through the liquid phase, replacing the need for gaseous hydrogen flow and simplifying the reactor system.
2Productivity
If hydrogen diffusion through liquid to catalyst surface is slow, then reaction rate is limited, but increasing hydrogen concentration increases hydrogen demand
Solution Approach 1:
The patent applies preliminary action by pre-saturating the liquid feed stream with hydrogen before it enters the reactor. This ensures that the liquid phase contains the maximum concentration of dissolved hydrogen available for diffusion to the catalyst surface, thereby maximizing the reaction rate without requiring excess hydrogen input.
Solution Approach 2:
The patent changes the physical-chemical parameters of the feed stream by adjusting its composition and saturation level with hydrogen. By optimizing the hydrogen concentration in the liquid phase and controlling feed stream properties, the system achieves optimal reaction rates while minimizing hydrogen demand.
3Productivity
If sulfur compounds react rapidly consuming hydrogen, then hydrogen availability for other reactions decreases, but reaction conditions must be maintained for desired conversions
Solution Approach 1:
The patent changes the feed stream composition and hydrogen saturation level to account for the rapid hydrogen consumption by sulfur compounds. By adjusting these parameters, the system ensures sufficient hydrogen is initially dissolved in the liquid phase to meet both the high sulfur compound reaction rates and the hydrogen needs of other desired reactions.
Solution Approach 2:
The patent uses a liquid-phase model that replicates the essential hydrogen transfer mechanism needed for reaction, eliminating the need for complex three-phase gas-liquid-solid systems. This simplified liquid-phase approach better controls hydrogen distribution and availability to different reaction sites.
4Productivity
If liquid-phase hydroprocessing is used, then hydrogen diffusion limitations are reduced, but hydrogen depletion occurs during reaction
Solution Approach 1:
The patent applies preliminary action by pre-saturating the liquid feed stream with hydrogen to maximum concentration before injection. This ensures that the liquid phase starts with the highest possible hydrogen content, which then diffuses to the catalyst throughout the reaction, maintaining adequate hydrogen levels and preventing depletion.
Solution Approach 2:
The patent ensures continuous hydrogen availability by maintaining hydrogen saturation in the liquid feed stream throughout the reaction process. The continuous supply of hydrogen-saturated liquid to the catalyst ensures that hydrogen diffusion and reaction proceed continuously without depletion limitations.
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 enhances hydrogen delivery to catalyst sites, maintaining consistent reaction rates and increasing conversion efficiency per pass, while reducing reactor size and complexity by minimizing hydrogen depletion and transport limitations.
Implementation Method 1
a liquid-phase feed stream to a first substantially liquid-phase hydroprocessing zone includes a hydrocarbonaceous feed stock, a previously hydroprocessed liquid-phase hydrocarbonaceous stream, and hydrogen
Implementation Method 2
for the hydrogen gas to get to the active sites on the catalyst, the hydrogen must first diffuse from the gas phase into the liquid-phase and then through the liquid to the reaction site adjacent the catalyst
Data Source
AI summary
Methods of hydroprocessing hydrocarbon streams are provided that employ substantially liquid-phase hydroprocessing conditions. In one aspect, the method includes directing a hydrocarbonaceous feed stock to a first substantially liquid-phase hydroprocessing zone wherein an effluent from the first substantially liquid-phase hydroprocessing zone is directed to a second substantially liquid-phase hydroprocessing zone generally undiluted with other hydrocarbon streams. In another aspect, the method recycles a liquid portion of a liquid hydrocarbonaceous effluent from the second substantially liquid-phase hydroprocessing zone, which preferably includes an amount of hydrogen dissolved therein, to the hydrocarbonaceous feed stock so that the feed to the first substantially liquid-phase hydroprocessing zone has a relatively larger concentration of dissolved hydrogen relative to the hydrocarbonaceous feed stock.