Rotary Solvent Recovery Loop Using Inert Gas Desorption
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Solution Overview
Problem
Conventional VOC abatement systems face challenges in completely separating organic solvents from carrier gases, inefficient solvent recovery, and potential safety hazards during mode transitions due to high VOC concentrations exceeding 25% LEL.
Innovation Solution
A contamination recovery system utilizing rotary wheel or carousel adsorbable concentrators with a desorption carrier gas closed loop stream, which minimizes air displacement with inert gas, enhancing solvent recovery and safety by using inert gases like nitrogen, and incorporating condensers and decanters for efficient solvent condensation and recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional adsorption/desorption systems are used to separate organic solvent from carrier gas, then solvent recovery is achieved, but complete separation is insufficient and regeneration is poor
Solution Approach 1:
The system divides the adsorption process into multiple beds operating in sequence, with each bed performing a specific function (adsorption, desorption, cooling, heating). This segmentation allows complete separation of solvent from carrier gas by distributing the separation task across multiple specialized stages rather than relying on a single adsorption/desorption cycle.
Solution Approach 2:
The system performs preliminary cooling of the adsorbent bed before adsorption and preliminary heating before desorption. This preliminary action optimizes the adsorbent's capacity and ensures complete solvent recovery by preparing the material in its optimal state before each operational phase.
2Object-generated harmful factors
If alternating adsorption/desorption modes are used with chamber switching, then contamination is removed, but unsafe conditions occur during mode transition when VOC concentration exceeds 25% LEL
Solution Approach 1:
The system introduces inert gas into the desorption chamber before the adsorption chamber is fully purged. This preliminary action creates a safe atmosphere in advance, ensuring that when mode transition occurs, the VOC concentration remains below explosive limits. The inert gas is pre-positioned to immediately dilute any VOC that might be present during switching.
Solution Approach 2:
The system uses inert gas (nitrogen or carbon dioxide) to create a non-flammable atmosphere in the desorption chamber before and during mode transitions. This inert environment prevents combustion even when VOC concentrations are high, eliminating the safety hazard associated with conventional alternating mode operations.
3Object-generated harmful factors
If conventional systems destroy organic solvent downstream with oxidizer, then pollution is reduced, but carbon footprint increases and solvent recovery is poor
Solution Approach 1:
The system recovers organic solvent through condensation of the desorbed vapor stream rather than destroying it with oxidation. The condensed solvent is collected and can be reused or properly disposed of, significantly reducing solvent loss and carbon footprint while still achieving pollution abatement through controlled recovery.
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 efficient solvent recovery, reduces the need for downstream thermal oxidation, minimizes carbon footprint, and ensures safe operation by maintaining high VOC concentration ratios below safety limits.
Implementation Method 1
a first rotary concentrator comprising an adsorption zone having at least one filter element for adsorbing the at least one adsorbable contaminant from a process gas
Implementation Method 2
a desorption zone; a process gas inlet for introduction of the process gas into the first rotary concentrator... a desorption carrier gas inlet for receiving a desorption carrier gas in the desorption zone for desorbing at least one adsorbable contaminant adsorbed by the at least one filter element
Implementation Method 3
the desorption carrier gas closed loop stream is also in fluid communication with a condenser for condensing at least one adsorbable contamination carried in the stream
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Contaminant recovery system and method for purifying a process gas containing at least one adsorbable contaminant. A first rotary concentrator has an adsorption zone having at least one filter element for adsorbing at least one adsorbable contamination from a process gas containing the at least one adsorbable contamination, and a desorption zone. An inert desorption carrier gas closed loop stream is in fluid communication with the desorption zone, a condenser, and a heat source for heating the carrier gas to a temperature effective for desorbing the at least one adsorbable contamination in the desorption zone. A second rotary concentrator may be included downstream of the first rotary concentrator.