Gasifier Gas Duct Geometry to Prevent Cooling Droplet Return
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Solution Overview
Problem
Existing reactors for partial oxidation of carbonaceous feedstocks face issues with the return of cooling medium in the form of liquid droplets from the cooling space to the reaction space, leading to thermal stress and potential material destruction due to abrupt transitions and improper flow profiles.
Innovation Solution
The reactor design includes a gas duct with a first region of constant diameter followed by a second region with a diverging diameter to establish a turbulent flow profile, preventing recirculation zones, and a cooling medium feed within the gas duct to form a liquid film for efficient cooling before the synthesis gas enters the cooling space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an abrupt transition is used from the outlet region of the reaction space to the cooling media feed region, then the device complexity is reduced, but liquid droplets from the multiphase region are transported back into the hot reaction space causing thermal stress and material destruction
Solution Approach 1:
The gas duct is divided into multiple regions: a first region with constant diameter and a second region with diverging diameter. This segmentation allows the flow profile to be controlled in stages, preventing recirculation zones while managing the transition from reaction space to cooling space, thereby protecting materials from thermal stress without excessive complexity
Solution Approach 2:
The diverging second region is designed to prevent recirculation flows before they can transport liquid droplets back into the reaction space. By establishing a favorable flow profile in advance, the system avoids the harmful effect of droplet return and thermal stress on materials
2Productivity
If cooling medium is introduced at high speed via nozzle system into the gas flow, then the cooling efficiency is improved, but liquid droplets are formed and may be transported back into hot regions causing thermal stresses
Solution Approach 1:
The gas duct design creates different flow conditions in different regions: the first region with constant diameter handles the high-speed cooling medium injection efficiently, while the second region with diverging diameter controls the flow profile to prevent recirculation. This local differentiation allows high cooling efficiency while avoiding droplet transport to hot regions
Solution Approach 2:
The diverging second region uses a curved geometry to gradually expand the flow cross-section, which helps to stabilize the flow profile and prevent the formation of recirculation zones that would transport droplets back into hot regions, thereby reducing thermal stress on materials
3Reliability
If a diverging diameter region is added to the gas duct, then recirculation zones are prevented and liquid droplet return is avoided, but the device complexity and length increase
Solution Approach 1:
The diverging second region is designed with a specific geometry that provides just enough flow control to prevent recirculation zones and droplet return. The design avoids excessive length by optimizing the diverging angle and region dimensions, achieving the necessary flow control with minimal additional length
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 liquid droplets, reducing thermal stress on reactor components and ensuring uniform cooling, thereby protecting materials and enhancing the reactor's operational safety and efficiency.
Implementation Method 1
the gas duct has a first region with a constant diameter and a second region with a diverging diameter in the flow direction of the synthesis gas to be cooled... to establish a turbulent flow profile, preventing recirculation zones
Implementation Method 2
a cooling medium feed is provided in the region of the gas duct... to form a liquid film for efficient cooling before the synthesis gas enters the cooling space
Data Source
AI summary
The invention relates to a reactor, in particular an entrained flow gasifier, for producing synthesis gas by partial oxidation of a carbonaceous feedstock. The reactor comprises a reaction space, a cooling space and a gas duct fluidically connecting the reaction space and the cooling space. The gas duct has a gas inlet region adjacent to the reaction space and a gas outlet region adjacent to the cooling space. The feeding of cooling medium is effected via the gas duct. According to the invention it is provided that in the flow direction of the synthesis gas to be cooled the gas duct has a first region and a second region connected thereto, wherein the first region has a constant diameter and the second region has a diverging diameter in the flow direction of the synthesis gas to be cooled.