Desublimating Heat Exchanger Stream Mixing for Fouling Control
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Solution Overview
Problem
Current systems for separating condensable vapors like carbon dioxide from light gases in direct contact heat exchangers face issues with heat-transfer inhibiting mass accumulation, such as frosting or fouling, which complicates temperature control and equipment maintenance in carbon dioxide sequestration processes.
Innovation Solution
A method and apparatus that split the liquid outlet stream from a desublimating heat exchanger into parallel streams, which are then processed through different unit operations to create streams of varying temperatures, mixed in a chamber to reach a uniform temperature, and recycled back into the heat exchanger, thereby reducing fouling and maintaining efficient temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If low temperatures are used for desublimation to convert carbon dioxide from gas to solid state, then separation efficiency is improved, but heat-transfer inhibiting mass accumulation (frosting or fouling) occurs on equipment elements
Solution Approach 1:
The patent changes the temperature parameter dynamically by introducing a temperature control system that adjusts the temperature of the heat exchange liquid. This prevents the equipment surface temperature from dropping low enough to cause frosting while maintaining conditions sufficient for CO2 desublimation and separation, thus resolving the contradiction between separation efficiency and fouling prevention
Solution Approach 2:
The patent implements a feedback control mechanism where temperature sensors monitor the temperature of the heat exchange liquid and equipment surfaces, and this information is used to adjust the heating/cooling rate in real-time. This feedback system ensures that temperature remains within an optimal range that achieves separation without causing harmful mass accumulation
2Temperature
If streams of various temperatures are mixed without control, then temperature control difficulties arise, but proper mixing can achieve uniform temperature and prevent freezing or vaporization issues
Solution Approach 1:
The patent controls the temperature parameter of mixed streams by introducing a heating/cooling system that adjusts the temperature of individual streams before mixing. This ensures that streams are combined at controlled temperatures, achieving uniform temperature output while preventing unwanted freezing or vaporization, thus resolving the contradiction between temperature uniformity and ease of operation
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 effectively decreases fouling and maintains uniform temperature distribution within the desublimating heat exchanger, enhancing the separation efficiency of carbon dioxide and reducing equipment maintenance needs.
Implementation Method 1
The NVHEL cools the process stream and causes the condensable vapors to desublimate, thereby forming a slurry of desublimated solids and the NVHEL
Implementation Method 2
Mixing the first parallel liquid stream with the second parallel liquid so that the first parallel liquid stream and the second parallel liquid have a substantially uniform temperature
Data Source
AI summary
A process to prevent fouling using a desublimating heat exchanger is disclosed. An outlet stream from the desublimating heat exchanger may be split into a plurality of parallel streams. The parallel streams may be sent through other devices for performing a unit operation, and the devices for performing a unit operation may change the temperature of at least one of the parallel streams. Parallel streams of differing temperature may emerge from the devices for performing a unit operation. The parallel streams of differing temperature may be sent to a mixing chamber. A mixed stream of uniform temperature may emerge from the mixing chamber, and the mixed stream may be recycled back to the desublimating heat exchanger. The mixing chamber may be separate from the desublimating heat exchanger, or the parallel streams of differing temperature may be mixed in the desublimating heat exchanger.