Down-flow Hydroprocessing Reactor Nozzle Mixing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In down-flow hydroprocessing reactors, poor interbed fluid mixing leads to temperature maldistribution, hot spots, and reduced catalyst lifetime, necessitating improved nozzle devices for efficient gas and liquid distribution to maintain reactor performance and prevent runaway reactions.
Innovation Solution
A nozzle device with a converging-diverging nozzle restrictor and offset gas and liquid inlets, designed to enhance mixing and reduce pressure drop, featuring a nozzle body with distinct zones for gas and liquid introduction and a frustoconical nozzle restrictor for efficient fluid mixing and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional nozzles are used for gas and liquid distribution, then the reactor can operate, but temperature maldistribution and hot spots occur due to poor interbed fluid mixing
Solution Approach 1:
The nozzle is divided into distinct functional zones: a gas inlet zone with multiple gas inlet ports, a liquid inlet zone with liquid inlet ports, and an exit zone. This segmentation allows independent optimization of gas and liquid flow paths, enabling effective mixing of the two phases while maintaining temperature uniformity and preventing hot spots that would otherwise degrade catalyst lifetime.
Solution Approach 2:
Different portions of the nozzle are designed with different properties: the gas inlet zone has multiple offset ports for gas distribution, the liquid inlet zone has dedicated liquid ports, and the exit zone provides controlled discharge. This local differentiation of functionality ensures that gas and liquid are introduced and mixed in specific regions, achieving uniform temperature distribution throughout the reactor bed.
2Temperature
If mixing intensity is increased to improve temperature uniformity, then temperature maldistribution is reduced, but pressure drop through the nozzle increases
Solution Approach 1:
The gas and liquid inlet zones are positioned to merge their flows within the nozzle body before exit. The offset ports are arranged so that gas and liquid streams combine and mix in a controlled manner within the nozzle, achieving effective mixing without requiring excessive pressure drop. The merged flow then exits uniformly to distribute both phases throughout the reactor bed.
Solution Approach 2:
The nozzle utilizes three-dimensional spatial arrangement of offset gas and liquid inlet ports to achieve mixing. Rather than relying solely on increased flow velocity (one dimension), the invention employs spatial distribution of multiple inlet ports at different locations and angles, creating multi-dimensional flow patterns that enhance mixing efficiency while maintaining acceptable pressure drop levels.
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
The nozzle device achieves effective mixing and distribution of gas and liquid phases, reducing pressure drop and operational costs, while improving reactor performance and catalyst longevity by maintaining uniform temperature and flow, thus preventing hot spots and runaway reactions.
Implementation Method 1
The nozzle provides effective mixing of an existing mixing volume in mixing the gas and liquid phases of two-phase systems, while providing for a reduced pressure drop through the nozzle
Data Source
AI summary
An improved nozzle device for a down-flow hydroprocessing reactor is disclosed. The down-flow nozzle is useful in the petroleum and chemical processing industries in catalytic reactions of hydrocarbon feedstocks in the presence of hydrogen, at an elevated temperature and pressure, to provide for the mixing and distribution of gas and liquid to reactor catalyst beds. Typical hydroprocessing applications include hydrotreating, hydrofinishing, hydrocracking and hydrodewaxing.