Desiccant Purification Column with Recycle Heating
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Solution Overview
Problem
Current desiccant regeneration systems face limitations in achieving high purity and concentration of desiccants like TEG due to thermal degradation and require large equipment sizes, leading to desiccant losses and inefficiencies in stripping gas usage.
Innovation Solution
A desiccant regeneration system featuring a vertical purification column with a distillation section, recycle heating, and open heating methods that allow for efficient heat transfer and reduced exposure to high temperatures, minimizing degradation and using a chimney tray for improved stripping efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If evaporation and stripping gas steps are used to purify desiccants, then purity is improved, but equipment size increases and desiccant losses occur
Solution Approach 1:
The patent combines the evaporation and stripping gas steps into a single integrated purification column, eliminating the need for separate equipment and reducing overall equipment size while maintaining high desiccant purity through the combined action of evaporation and stripping zones
Solution Approach 2:
The invention introduces a reflux stream as an intermediary that facilitates heat and mass transfer within the purification column, enabling efficient purification without requiring large equipment volumes by creating a controlled intermediate zone for phase change and mixing
2Manufacturing precision
If stripping gas is used to increase water stripping efficiency, then desiccant concentration is improved, but stripping gas consumption increases
Solution Approach 1:
The patent implements a reflux stream that takes a portion of the purified desiccant, heats it, and returns it to the purification column. This creates a feedback mechanism where the reflux stream continuously enhances water stripping efficiency through counter-current contact with the rising vapor, reducing the need for additional stripping gas
Solution Approach 2:
The invention utilizes phase transitions of water (liquid to vapor) within the purification column, where the reflux stream promotes efficient phase change and mass transfer, allowing high desiccant concentration to be achieved with reduced stripping gas consumption by leveraging the latent heat and mass transfer during vaporization
3Productivity
If reboiler temperature is increased to achieve higher desiccant concentration, then purification efficiency is improved, but desiccant degradation increases
Solution Approach 1:
The patent employs dynamic flow conditions within the purification column, where the reflux stream creates continuous mixing and movement of the desiccant solution. This dynamic environment prevents localized overheating and stagnant zones, allowing efficient purification at moderate temperatures while minimizing desiccant degradation through reduced thermal exposure time
Solution Approach 2:
The invention enables the desiccant solution to rapidly pass through the high-temperature zones within the purification column via the reflux mechanism. This 'rushing through' effect minimizes the residence time at elevated temperatures, achieving high purification efficiency while limiting thermal degradation by quickly moving the desiccant through the critical temperature zone
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 system achieves high purity (>99.3 w/w %) desiccants with reduced equipment size and stripping gas consumption, minimizing desiccant losses and thermal degradation, while maintaining efficient heat transfer and process control.
Implementation Method 1
a recycle heater with an inlet in fluid communication with the outlet of the recycle pump and having an outlet, wherein the outlet of the recycle heater is in fluid communication with the purification column
Implementation Method 2
heating the rich desiccant stream with heat exchange with a top gas stream, flashing the heated rich desiccant stream
Implementation Method 3
a vertical purification column comprising a distillation section
Implementation Method 4
the boiling point temperature of high concentrated TEG exceeds the degradation temperature
Implementation Method 5
flashing the heated rich desiccant stream by feeding the heated desiccant stream to a vertical purification column
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
Desiccant regeneration system comprising - a vertical purification column (40) comprising - a distillation section (48), - a rich desiccant inlet (27) below the distillation section, a stripping gas and vapour outlet (51) above the distillation section and a liquid outlet (60) at the bottom part of the purification column, - a first heat exchanger (26, 126) for heating a rich desiccant stream upstream the a rich desiccant inlet (27), wherein the system further comprises - a recycle pump (62) comprising an inlet in fluid communication with a first liquid level in said column below the rich desiccant inlet and comprising an outlet, - a recycle heater (64) with an inlet in fluid communication with the outlet of the recycle pump (62), and a recycle heater outlet in fluid communication with said purification column (40) via a recycle conduit (65), and - a valve or orifice (76) on said recycle conduit (65) such that fluid recycled through the recycle heater is depressurized before entering said purification column. A method for using said system is also disclosed.