VSA Unit Repressurization Using Inert Gas to Prevent Flammable Mixtures
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Solution Overview
Problem
Existing CO2 capture processes, particularly those using adsorption, face challenges such as high energy requirements for regeneration and the risk of creating flammable atmospheres during shutdowns or isolation in vacuum swing adsorption (VSA) units, especially when dealing with gas mixtures containing hydrogen and carbon monoxide.
Innovation Solution
Implementing a VSA process with a vacuum pump repressurization system using an external inert gas, such as nitrogen or a gas enriched in CO2, to quickly repressurize the unit and prevent the formation of flammable mixtures, while also optimizing the adsorption cycle and adsorbent arrangement for efficient CO2 capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If VSA unit is shut down or isolated, then maintenance or emergency response is enabled, but flammable atmosphere may form due to air ingress during vacuum regeneration
Solution Approach 1:
The system performs preliminary repressurization of the vacuum pump and adsorber with inert gas before shutdown or isolation. This advance action ensures that when the unit is taken offline for maintenance or emergency response, the internal atmosphere is already protected from flammability risks, preventing air ingress from creating hazardous conditions during the vacuum regeneration phase.
Solution Approach 2:
The patent introduces an inert gas (such as nitrogen or CO2-enriched gas) into the vacuum pump and adsorber system to create an inert atmosphere. This inert environment displaces oxygen and prevents the formation of flammable mixtures with combustible gases (hydrogen, carbon monoxide) present in the syngas stream, thereby eliminating the fire hazard during shutdown or isolation scenarios.
2Use of energy by moving object
If conventional repressurization methods are used during shutdown, then system pressure is restored, but energy consumption increases and safety risks remain
Solution Approach 1:
The system uses inert gas stored in a dedicated tank to repressurize the vacuum pump and adsorber during shutdown or between cycles. This approach eliminates the need for high-energy vacuum pumping operations during repressurization and ensures safety by maintaining an oxygen-deficient atmosphere, thereby simultaneously reducing energy consumption and eliminating safety risks associated with conventional air-based repressurization methods.
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 reduces the risk of flammable atmosphere formation and lowers energy consumption by allowing rapid repressurization without using oxidizers, enhancing the safety and efficiency of CO2 capture processes in VSA units.
Implementation Method 1
a vacuum pump, which is depressurized during the cycle
Implementation Method 2
repressurized by at least partly a gas external to said unit and not containing oxidizer in sufficient quantity to create an flammable mixture
Implementation Method 3
separating or purifying a gas mixture, by adsorption
Data Source
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AI summary
A process for purifying or separating a gaseous mixture comprising at least one fuel, employing a unit having at least one adsorber (4) subjected to a pressure cycle comprising at least one vacuuming step using a vacuum pump (9), characterized in that at least one adsorber and/or the vacuum pump, depressurized during the cycle, is repressurized by at least part of a gas external to said unit and not containing an oxidizer in sufficient quantity to create a flammable mixture during this repressurization.