Hydroprocessing Reactor Liquid Mass Flux via Dissolved Hydrogen
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Solution Overview
Problem
Conventional hydroprocessing methods require large volumes of hydrogen gas, leading to massive reactors and high-pressure separators, which are costly and inefficient, with liquid mass flux limited to 1,000 to 5,000 lb/hr·ft2 due to pressure drop, hydrogen mass transfer, and wetting inefficiencies.
Innovation Solution
A hydroprocessing method where hydrogen gas is combined with a liquid feedstock and diluent to form a feed stream, with a significant portion dissolved, allowing for a liquid mass flux of 5,000 lb/hr·ft2 or more, and using a small amount of non-dissolved hydrogen gas, eliminating the need for large high-pressure separators by maintaining a near-stagnant gas volume within the reactor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If large volumes of hydrogen gas are circulated through the reactor, then hydrogen availability for reaction is improved, but reactor size and capital equipment cost increase
Solution Approach 1:
The invention changes the physical state parameter of hydrogen from gas phase to dissolved phase in liquid. By dissolving hydrogen in the liquid feedstock, the process achieves high hydrogen availability without requiring large volumes of gaseous hydrogen circulation, thereby reducing reactor size and associated capital equipment costs while maintaining effective hydrogen supply for the hydroprocessing reactions.
Solution Approach 2:
The liquid feedstock acts as an intermediary carrier for hydrogen transport. Instead of directly circulating large volumes of hydrogen gas through the reactor, the invention uses the liquid feedstock as a medium to dissolve and transport hydrogen to the catalyst, eliminating the need for large high-pressure separators and reducing reactor dimensions.
2Productivity
If liquid mass flux is increased beyond 5,000 lb/hr·ft2, then processing efficiency is improved, but pressure drop and hydrogen mass transfer limitations worsen
Solution Approach 1:
The invention changes the phase parameter of hydrogen from gas to dissolved state in liquid, which fundamentally alters the mass transfer dynamics. This parameter change eliminates gas-liquid mass transfer limitations that normally constrain liquid mass flux, allowing the process to operate at flux rates exceeding 5,000 lb/hr·ft2 without experiencing excessive pressure drop or hydrogen transfer bottlenecks.
3Productivity
If liquid mass flux is increased beyond 5,000 lb/hr·ft2, then processing efficiency is improved, but wetting inefficiencies worsen
Solution Approach 1:
By changing hydrogen from a separate gas phase to a dissolved phase in the liquid feedstock, the invention creates a homogeneous liquid mixture that flows uniformly through the catalyst bed. This eliminates the two-phase flow regime that causes wetting inefficiencies at high liquid mass flux rates, ensuring reliable catalyst contact and consistent reaction performance even at flux rates above 5,000 lb/hr·ft2.
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 enables higher liquid mass flux rates without constraints on feedstock quality or catalyst size, reducing hydrogen gas requirements, and replacing large separators with smaller ones, resulting in significant cost savings and improved process efficiency.
Implementation Method 1
At least a portion of the hydrogen gas is dissolved in the liquid feed composition of the feed stream
Implementation Method 2
a catalyst is used for reacting hydrogen with hydrocarbons, such as a petroleum fraction, distillates, resids, or other hydrocarbon compounds, for the purpose of saturating olefins or removing heteroatoms
Data Source
AI summary
In a method of hydroprocessing, hydrogen gas for the hydroprocessing reaction is combined with a liquid feed composition comprising a feedstock to be treated and a diluent to form a feed stream, at least a portion of the hydrogen gas being dissolved in the liquid feed composition of the feed stream, with non-dissolved hydrogen gas being present in the feed stream in an amount of from 1 to 70 SCF/bbl of the liquid feed composition. The feed stream is contacted with a hydroprocessing catalyst, within a reactor while maintaining a liquid mass flux within the reactor of at least 5000 lb/hr·ft2 to form a hydroprocessed product.