Slurry Bed Hydroprocessing Reactor Gas Hold-Up Reduction
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Solution Overview
Problem
Slurry bed hydroprocessing reactors face issues with gas hold-up and inefficient use of reactor space due to the presence of hydrogen gas, which reduces liquid residence time and limits hydrogen partial pressure, leading to suboptimal conversion rates and increased reactor size requirements.
Innovation Solution
Dissolving a substantial portion of the required hydrogen in the liquid hydrocarbon feedstock upstream of the slurry bed reactor, eliminating gas phase hydrogen and operating as a single-phase or two-phase system, thereby minimizing gas hold-up and optimizing reactor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If hydrogen gas is present in the slurry bed reactor, then hydrogenation reactions can proceed, but gas hold-up increases and liquid residence time decreases
Solution Approach 1:
The patent transitions the system from a two-phase (gas-liquid) to a single-phase (liquid) system by dissolving hydrogen gas into the liquid hydrocarbon feedstock. This phase transition eliminates gas hold-up while maintaining hydrogen availability for reactions, thereby maximizing liquid residence time in the reactor.
Solution Approach 2:
The patent changes the physical state of hydrogen from gaseous to dissolved state by adjusting parameters such as pressure and temperature in a hydrogen dissolution zone upstream of the reactor. This parameter change allows hydrogen to be present in the liquid phase without forming gas bubbles, resolving the contradiction between hydrogen availability and residence time.
2Quantity of substance
If gas phase hydrogen is used in the reactor, then hydrogen supply is maintained, but reactor space utilization becomes inefficient
Solution Approach 1:
By dissolving hydrogen gas into the liquid phase, the patent eliminates the need for gas phase hydrogen in the reactor. This phase transition allows the entire reactor volume to be utilized for liquid hydrocarbon processing, thereby improving reactor space utilization while maintaining adequate hydrogen supply through the dissolved hydrogen in the liquid feedstock.
3Reliability
If hydrogen partial pressure is limited due to gas hold-up, then safety is improved, but conversion rates decrease
Solution Approach 1:
The patent changes the mode of hydrogen delivery from gas phase (where partial pressure controls hydrogen availability) to dissolved phase in liquid (where concentration controls hydrogen availability). This parameter change allows high hydrogen concentrations to be achieved without relying on high partial pressures, thereby maintaining safety while improving conversion rates through enhanced hydrogen availability in the liquid phase.
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 conversion rates, reduces reactor size, and improves efficiency by maintaining a stable hydrogen partial pressure, allowing for higher liquid residence times and more effective hydroprocessing without the need for additional gas phase hydrogen, resulting in improved product quality and reduced operational costs.
Implementation Method 1
Dissolving a substantial portion of the required hydrogen in the liquid hydrocarbon feedstock upstream of the slurry bed reactor
Data Source
Figure 1
Figure 2A~2B
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AI summary
A system and process for conversion of heavy feedstocks in a slurry bed hydroprocessing reactor is provided in which (a) hydrogen gas is dissolved in the liquid feedstock by mixing and/or diffusion, (b) the mixture is flashed to remove and recover any light components and hydrogen, leaving a hydrogen-enriched feedstock. A homogenous and/or heterogeneous catalyst is added to the feedstock upstream of the inlet of the slurry bed hydroprocessing reactor.