Simultaneous Cocurrent and Countercurrent Depressurization in PSA Hydrogen Recovery
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Solution Overview
Problem
Conventional pressure swing adsorption processes in hydrogen production systems from natural gas reforming lose high purity hydrogen remaining in the zeolite layer during desorption, leading to reduced recovery rates and contamination of the adsorption bed due to excessive cocurrent depressurization.
Innovation Solution
Simultaneously performing cocurrent and countercurrent depressurization in the desorption step of the pressure swing adsorption process, with specific pressure ranges for each, to recover remaining hydrogen and prevent adsorption bed contamination, using adsorption beds filled with activated carbon and zeolite for impurity removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If cocurrent depressurization is excessively performed to remove impurities, then impurity removal is improved, but hydrogen recovery rate deteriorates due to loss of high purity hydrogen in zeolite layer
Solution Approach 1:
The depressurization process is segmented into two distinct directions: cocurrent depressurization for impurity removal and countercurrent depressurization for hydrogen recovery. This segmentation allows each direction to perform its specific function optimally without interfering with the other, resolving the contradiction between impurity removal and hydrogen recovery
Solution Approach 2:
The invention introduces a new dimension to the depressurization process by performing depressurization in two opposite directions (cocurrent and countercurrent) simultaneously. This dimensional approach allows the system to address both impurity removal and hydrogen recovery through different flow paths, transforming a single-direction limitation into a multi-directional solution
2Object-generated harmful factors
If countercurrent depressurization starts at high pressure to prevent adsorption bed contamination, then bed contamination is reduced, but hydrogen recovery is worsened as high purity hydrogen remains trapped in zeolite layer
Solution Approach 1:
Cocurrent depressurization is performed as a preliminary action before countercurrent depressurization. This preliminary step removes impurities and prepares the system for subsequent hydrogen recovery through countercurrent depressurization, ensuring that the adsorption bed is ready to receive recovered hydrogen without contamination
Solution Approach 2:
The invention applies the principle of discarding impurities through cocurrent depressurization while recovering high purity hydrogen through countercurrent depressurization. This dual approach allows selective discarding of harmful substances and recovery of valuable hydrogen, resolving the contradiction between preventing contamination and maximizing recovery
3Device complexity
If conventional sequential depressurization is used, then process simplicity is maintained, but productivity deteriorates due to hydrogen loss and repeated depressurization cycles
Solution Approach 1:
The invention merges cocurrent and countercurrent depressurization into a single integrated desorption step that operates simultaneously in two directions. This merging eliminates the need for separate sequential operations, maintaining process simplicity while significantly improving hydrogen recovery rate and productivity through the combined effects of both depressurization directions
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
Improves process efficiency by minimizing hydrogen loss and increasing recovery rates while reducing adsorption bed contamination, allowing for higher purity hydrogen recovery and efficient desorption of impurities.
Implementation Method 1
activated carbon is filled in a lower end thereof in which the gas to be purified is introduced and zeolite is filled in an upper end thereof to thereby mainly adsorb and remove carbon dioxide through the activated carbon at a high adsorption pressure
Implementation Method 2
zeolite is filled in an upper end thereof to thereby mainly adsorb and remove methane and carbon monoxide through the activated carbon
Implementation Method 3
a desorption step was then performed in which the adsorbed impurities are removed through an additional cocurrent depressurization followed by a separate countercurrent depressurization
Data Source
AI summary
According to an exemplary embodiment of the present invention, a pressure swing adsorption process of a hydrogen production system is provided. The hydrogen production system includes a desulfurization process for removing sulfur components from raw natural gas; a reforming reaction process for producing a reformed gas containing hydrogen generated by the reaction of natural gas through the desulfurization process and steam; and a pressure swing adsorption process of concentrating the hydrogen using a pressure swing adsorption from the reformed gas. In a desorption step of the pressure swing adsorption process, a cocurrent depressurization and a countercurrent depressurization are simultaneously performed.