Radioactive Mixture Drying via Boiling Lance and Vacuum
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Solution Overview
Problem
Existing methods for drying radioactive liquid-solid mixtures face issues such as delays in boiling, unwanted splattering, and inhomogeneous drying, leading to inefficient use of drying time and increased radiation exposure for personnel, due to complex and economically unfavorable processes.
Innovation Solution
A method involving a drying container with a boiling lance that extends over most of the container height, featuring multiple outlet openings for gas injection to homogenize the mixture and reduce pressure, allowing for batchwise refilling and concentration until a solid residue with low moisture content is achieved, combined with automatic pressure control to optimize the drying process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the liquid-solid mixture is heated for drying, then the liquid evaporates and drying progresses, but delays in boiling and unwanted spattering occur
Solution Approach 1:
The mixture is preheated to a temperature Tv below the boiling point before pressure reduction is initiated. This preliminary heating action prepares the mixture for evaporation while avoiding sudden boiling when vacuum is applied, thus preventing spattering and delays in boiling onset
Solution Approach 2:
The drying process alternates between heating phases and pressure reduction phases in a controlled sequence. This periodic cycling allows the mixture to progressively evaporate without sudden phase changes, maintaining process stability while achieving continuous drying
2Productivity
If the drying process is accelerated, then productivity increases, but inhomogeneous drying layers form causing heat-insulating effects
Solution Approach 1:
The container and mixture are preheated before vacuum application to ensure uniform temperature distribution throughout the mixture. This preliminary thermal conditioning prevents localized overheating and ensures homogeneous evaporation rates, avoiding heat-insulating layer formation
Solution Approach 2:
The drying process maintains continuous heating and pressure reduction without interruption, ensuring uniform evaporation throughout the mixture. This continuous action prevents the formation of dry layers that would insulate underlying material and slow further drying
3Ease of operation
If manual interventions are increased to manipulate the drying process, then process control improves, but radiation exposure of operating personnel increases
Solution Approach 1:
The system automatically controls heating and pressure reduction through integrated sensors and control mechanisms. The drying process self-regulates by monitoring temperature and pressure parameters, eliminating the need for manual interventions and thereby reducing personnel radiation exposure
Solution Approach 2:
The system incorporates feedback control where sensors monitor the drying progress and automatically adjust heating and vacuum levels. This closed-loop control maintains optimal drying conditions without human intervention, improving both process control and safety
4Quantity of substance
If the drying container is filled to maximize capacity, then storage efficiency improves, but drying time increases due to heat-insulating effects
Solution Approach 1:
The entire container and its contents are preheated before drying begins, ensuring that even deeply buried material reaches optimal evaporation temperature. This eliminates the time delay that would normally occur in densely filled containers where heat penetration is slow
Solution Approach 2:
Continuous heating and vacuum application maintain uniform drying throughout the container volume, preventing the formation of insulating layers even in densely packed conditions. This ensures that all material dries at the same rate regardless of position
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 efficient, trouble-free drying with high container filling capacity, reduced radiation exposure, and economic benefits by minimizing manual interventions and achieving a highly homogeneous, dense solid residue with low residual moisture.
Implementation Method 1
the container interior is heated and a negative pressure is applied to the container interior, so that liquid of the liquid-solid mixture is evaporated
Implementation Method 2
a negative pressure is applied to the container interior, so that liquid of the liquid-solid mixture is evaporated
Implementation Method 3
a gas - in particular air - via the boiling lance and its outlet openings in the Mixture is blown or bubbled
Data Source
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AI summary
A method for drying radioactively contaminated liquid-solid mixtures (2), wherein the mixture is dried in a container interior (3) of a drying vessel (1). For this purpose, the container interior (3) is heated and a negative pressure is applied to the container interior (3) so that liquid from the mixture (2) evaporates. At least one boiling lance (9) with at least one outlet opening (10) projects into the mixture (2) arranged in the container interior (3). The drying of the mixture (2) is carried out by first filling a portion of the mixture (2) into the container interior (3) and then drying it, followed by filling in another portion of the mixture (2) and drying the resulting liquid mixture, the drying process being continued until a solid residue remains.