Gasifier Gas Passage Geometry to Prevent Cooling Droplet Recirculation
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Solution Overview
Problem
Existing reactors for partial oxidation of carbon-containing feedstocks face issues with recirculation of cooling medium droplets from the cooling chamber back into the reaction chamber, causing thermal stress and material degradation due to high temperatures, particularly when using non-purified cooling water containing alkali and alkaline earth metal compounds.
Innovation Solution
The reactor design includes a gas passage with a first region of constant diameter followed by a second region with a divergent diameter to stabilize the flow, reducing recirculation zones and minimizing contact between hot synthesis gas and cooling medium, combined with a flow guide element and cooling medium supply to create a liquid film for efficient cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a sudden transition from reaction chamber outlet to cooling medium supply area is used, then the cooling process is simple and direct, but recirculation flow develops causing water droplets to be transported back into the hot reaction chamber
Solution Approach 1:
The gas passage is segmented into a first region with constant diameter and a second region with divergent diameter. This segmentation allows the flow to be controlled in stages: the first region maintains high velocity for efficient cooling, while the second region gradually expands to stabilize the flow and prevent recirculation, thereby resolving the contradiction between cooling efficiency and material integrity.
Solution Approach 2:
The flow stabilization is performed preliminarily in the second region before the cooled gas enters the cooling chamber. By implementing the diameter divergence in advance, recirculation is prevented before water droplets can form and be transported back to the reaction chamber, protecting the materials from thermal stress.
2Ease of manufacture
If cooling medium is supplied directly in the cooling chamber, then the cooling process is straightforward, but thermal stress and material degradation occur due to recirculated droplets encountering high temperatures
Solution Approach 1:
The second region with divergent diameter acts as an intermediary zone between the cooling medium supply area and the cooling chamber. This intermediary structure stabilizes the flow and prevents recirculation, thereby eliminating the harmful thermal stress on materials while maintaining the simplicity of direct cooling medium supply.
3Device complexity
If a constant diameter gas passage is used throughout, then the structure is simple and easy to manufacture, but recirculation zones form causing inefficient cooling and potential material damage
Solution Approach 1:
Different sections of the gas passage are given different diameter characteristics tailored to their specific functions. The first region has constant diameter optimized for high-velocity flow and efficient cooling, while the second region has divergent diameter optimized for flow stabilization. This local differentiation improves cooling efficiency without excessive structural complexity.
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 design effectively prevents the return of cooling medium droplets to the reaction chamber, reducing thermal stress and material degradation while ensuring consistent and efficient cooling of synthesis gas.
Implementation Method 1
a gas passage fluidically connecting the reaction chamber and cooling chamber, which has a gas inlet area adjacent to the reaction chamber and a gas outlet area adjacent to the cooling chamber, wherein the supply of cooling medium is provided in the area of the gas passage. According to the invention, the gas passage has a first region and a second region adjoining it in the flow direction of the synthesis gas to be cooled, wherein the first region has a constant diameter and the second region has a diameter that diverges in the flow direction of the synthesis gas to be cooled.
Implementation Method 2
combined with a flow guide element and cooling medium supply to create a liquid film for efficient cooling
Implementation Method 3
a cooling chamber comprising a synthesis gas outlet and a cooling medium outlet, wherein the cooling chamber is designed for cooling the synthesis gas by direct cooling with a cooling medium
Data Source
Figure 1
AI summary
The invention relates to a reactor, in particular a fluidized bed gasifier, for the production of synthesis gas by partial oxidation of a carbon-containing feedstock. The reactor comprises a reaction chamber, a cooling chamber, and a gas passage connecting the reaction chamber and cooling chamber fluidically. The gas passage has a gas inlet region adjacent to the reaction chamber and a gas outlet region adjacent to the cooling chamber. Cooling medium is supplied via the gas passage. According to the invention, the gas passage has a first region and a second region adjoining it in the flow direction of the synthesis gas to be cooled, wherein the first region has a constant diameter, and the second region has a diameter that diverges in the flow direction of the synthesis gas to be cooled.