Hydroprocessing Liquid Quench for Hydrogen Transfer
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Solution Overview
Problem
Conventional hydroprocessing methods face challenges in efficiently transferring and maintaining available hydrogen to catalysts in high severity hydrotreating units, leading to suboptimal performance and catalyst deactivation due to high pressures and temperatures, as well as contamination from sulfur, nitrogen, and metals in hydrocarbon feed streams.
Innovation Solution
Implementing a liquid quench from a hot, high-pressure separator to enhance hydrogen availability and catalyst contact, allowing for continuous flow of hydrogen and hydrocarbon liquids across a densely packed catalyst bed, with the liquid quench injected between catalyst beds to increase residence time and penetration, and optionally cooled to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If very large volumes of hydrogen gas are circulated through the catalyst bed, then hydrogen transfer to liquid phase is improved, but device complexity and operating cost increase
Solution Approach 1:
The patent uses a liquid quench medium as an intermediary to transfer hydrogen to the catalyst bed. Instead of directly circulating large volumes of hydrogen gas, the liquid quench absorbs hydrogen and delivers it to the catalyst, reducing the complexity of the circulation system while maintaining effective hydrogen transfer.
Solution Approach 2:
The invention employs hydraulic principles by using liquid quench under pressure to deliver hydrogen to the catalyst bed. The liquid phase transport of hydrogen replaces gas phase circulation, utilizing fluid dynamics to achieve more efficient and simpler hydrogen delivery.
2Productivity
If high pressures and temperatures are used in hydroprocessing, then reaction rate is improved, but catalyst deactivation increases
Solution Approach 1:
The liquid quench is applied preliminarily between catalyst beds to cool the hydrocarbon stream before it reaches subsequent catalyst beds. This preliminary cooling action prevents excessive temperature buildup that would cause catalyst deactivation, while still allowing high reaction rates in each individual bed by maintaining optimal temperature conditions.
Solution Approach 2:
The catalyst system is segmented into multiple beds with liquid quench injection between them. This segmentation allows each bed to operate at optimal high temperature for reaction rate, while the inter-bed cooling prevents cumulative temperature rise that would lead to catalyst deactivation, thus maintaining both productivity and reliability.
3Duration of action of moving object
If liquid quench is injected between catalyst beds, then residence time and penetration are improved, but processing complexity increases
Solution Approach 1:
The liquid quench system serves multiple functions simultaneously: it cools the hydrocarbon stream, delivers hydrogen to the catalyst, and increases residence time. This self-service approach means that adding the quench injection system provides multiple benefits without proportionally increasing complexity, as one system accomplishes what would otherwise require multiple separate systems.
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 processing rates and longer operation times with lower sulfur levels, achieving 54 M BPD at 6 ppm sulfur with heavier, more cracked feedstocks, while maintaining catalyst effectiveness and reducing deactivation rates.
Implementation Method 1
the hydrogen is absorbed into a thin film of oil that is distributed over the catalyst
Implementation Method 2
quenching in hydroprocessing of a hydrocarbon feed stream through a hydroprocessing vessel
Data Source
AI summary
The present invention relates to quenching, during hydroprocessing of a hydrocarbon feed stream. More particularly, the present invention provides for quenching in hydroprocessing of a hydrocarbon feed stream through a hydroprocessing vessel. Liquid quenches (from high pressure hot separator) were installed to assist in cooling the reactor inter-bed, and to maintain good liquid irrigation of the catalyst. The soluble hydrogen in the stream, kinetically active and available for immediate reaction, is the final piece of the puzzle for why this unit runs so well.