Cold-Wall Reactor Inner Liner Design for Suspension-Bed Hydrogenation
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Solution Overview
Problem
Suspension-bed reactors face challenges in evenly mixing air, liquid, and solid phases, leading to uneven temperature distribution, low reaction efficiency, and coking due to high wall temperatures and inadequate mixing of materials with cold hydrogen in existing cold-wall reactors.
Innovation Solution
A cold-wall reactor design featuring a reactor body with a cold hydrogen gas inlet on the side wall, a feed inlet at the bottom, and an inner liner cylinder with a first and second circulation channel, allowing for uniform mixing of three-phase materials and improved temperature uniformity through the use of a thermal insulation liner and strategically placed air holes to enhance fluid flow and mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a hot-wall reactor is used for suspension-bed hydrocracking, then the reaction temperature can be maintained, but the wall temperature is high causing materials to coke on the side wall and affecting fluidity
Solution Approach 1:
The reactor is divided into two distinct zones: a hot inner reaction zone where catalysis occurs, and a cold outer wall zone that prevents coking. The inner liner is separated from the outer shell by an insulation layer, creating spatial segmentation of temperature zones.
Solution Approach 2:
Different parts of the reactor have different temperature characteristics - the inner reaction zone maintains high temperature for catalysis while the outer wall remains cold to prevent coking. This local quality differentiation resolves the contradiction between maintaining reaction temperature and preventing wall coking.
2Temperature
If cold hydrogen gas enters through limited inlets in existing cold-wall reactors, then the reactor wall temperature is reduced, but the three-phase materials cannot be mixed uniformly and local hot spots cause coking
Solution Approach 1:
The single-point hydrogen inlet is transformed into a distributed multi-point inlet system arranged in specific patterns. This dimensional change from 0D (point) to 1D/2D (distributed) enables uniform three-phase mixing while maintaining the cold-wall effect.
Solution Approach 2:
Cold hydrogen is introduced at multiple predetermined locations before the reaction materials reach those zones, ensuring pre-mixing occurs throughout the reactor volume. This preliminary distribution of cold hydrogen prevents local hot spots before they can form.
3Speed
If the fluid linear velocity near the wall surface is low due to wall effect, then gas entering the reactor is not evenly distributed and short circuits occur, but increasing velocity would worsen the wall effect
Solution Approach 1:
The reactor employs asymmetric structural features including angled inner liner walls and strategically positioned hydrogen inlets that are not uniformly distributed. This asymmetry disrupts the symmetric wall effect and promotes more uniform gas distribution throughout the reactor volume.
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 design ensures uniform mixing of materials, reduces coking, and enhances reaction efficiency by maintaining a consistent temperature and preventing material aggregation, while also protecting the reactor from corrosion.
Implementation Method 1
a side wall of the inner lining cylinder and an inner side wall of the reactor body define a cavity serving as a first circulation channel
Implementation Method 2
cold hydrogen gas inlet arranged on a side wall thereof... uniformly mixed with the materials in the inner liner cylinder
Implementation Method 3
the hydrogen can be quickly dissolved to the required raw materials, which make the hydrogenation occur
Implementation Method 4
the hydrogen and the raw materials can fully react on the surface of the catalyst and the hydrogen can be quickly dissolved to the required raw materials, which make the hydrogenation occur
Data Source
AI summary
A cold-wall reactor for suspension-bed hydrogenation includes a reactor body including a reaction product outlet, cold hydrogen gas inlet and feed inlet. The reactor body includes a housing, surfacing layer and thermal insulation liner. An inner lining cylinder is fixedly arranged inside the reactor body with an outlet connected with the reaction product outlet. A side wall of the inner lining cylinder and an inner side wall of the reactor body define a cavity serving as a first circulation channel. A second circulation channel is arranged on the inner lining cylinder side wall. The inner lining cylinder communicates with the first circulation channel through the second circulation channel. In suspension-bed hydrogenation, material temperature is more uniform, reaction efficiency is improved, materials coking is reduced, thermal insulation liner issues are prevented, and the temperature of the outer wall of the reactor body is lower than the temperature of the medium.