PSA Tail Gas Flow Stabilization via Intelligent Mixing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pressure swing adsorption (PSA) processes experience fluctuations in flow rate and instantaneous fuel value of tail gas, leading to inefficiencies in reformer furnace operation, as the cyclic nature of PSA processes results in varying pressure and component concentrations, necessitating larger surge vessels and excess oxidant usage to maintain stable combustion.
Innovation Solution
The process involves intelligent mixing of purge gas and blowdown gas streams within the PSA cycle to create a by-product gas with a substantially constant flow rate and fuel property value, achieved by regulating flow rates and fuel properties through valves and characteristic curves, allowing for reduced surge vessel size and optimized oxidant usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PSA cyclic operation is used, then hydrogen separation is achieved, but tail gas flow rate and fuel value fluctuate
Solution Approach 1:
The patent applies preliminary action by conducting equalization steps before the main separation steps. During equalization, gas is transferred between beds to pre-balance pressures and compositions, which stabilizes the tail gas flow before it enters the surge vessel. This preliminary gas transfer between beds during equalization steps reduces subsequent flow fluctuations.
2Reliability
If surge vessel size is increased to dampen flow fluctuations, then tail gas flow stability improves, but capital cost and system complexity increase
Solution Approach 1:
The patent implements feedback control by using sensors to monitor tail gas flow rate and fuel value in real-time, then adjusting valve positions and oxidant flow accordingly. The combustion air flow is controlled based on measured tail gas composition to maintain stable combustion despite flow variations, reducing the need for oversized surge vessels.
3Reliability
If excess oxidant is used to maintain stable combustion, then combustion stability improves, but energy efficiency decreases
Solution Approach 1:
The patent uses feedback control with oxygen sensors to monitor combustion exhaust and adjust oxidant flow in real-time. The combustion air flow rate is dynamically controlled based on measured tail gas composition and flow rate, maintaining optimal combustion conditions without excessive oxidant usage, thereby improving energy efficiency while preserving combustion stability.
4Stability of the object's composition
If tail gas flow fluctuations are reduced through intelligent mixing, then by-product gas fuel property stability improves, but process control complexity increases
Solution Approach 1:
The patent implements feedback control by continuously measuring tail gas flow rate and fuel value using sensors, then automatically adjusting valve positions and oxidant flow rates based on these measurements. This closed-loop control stabilizes the by-product gas fuel properties while managing control complexity through automated regulation.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting valve positions, flow rates, and oxidant composition based on real-time measurements of tail gas flow and fuel value. These parameter adjustments compensate for cyclic variations and stabilize the by-product gas fuel properties without requiring fundamentally new process equipment.
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 stabilizes the flow rate and fuel properties of the by-product gas, enabling smaller surge vessels, lower operating pressures, and improved efficiency in steam-hydrocarbon reforming processes by minimizing excess oxidant and maintaining consistent combustion conditions, thus enhancing furnace efficiency and yield.
Implementation Method 1
Pressure swing adsorption (PSA) processes are well-known for the separation of gas mixtures that contain components with different adsorbing characteristics
Implementation Method 2
a multicomponent gas is passed to at least one of multiple adsorption beds at an elevated pressure to adsorb at least one strongly sorbed component
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Pressure swing adsorption process for reducing fluctuations in the flow rate of tail gas from the adsorption unit and reducing fluctuations in the stoichiometric oxidant flow rate required to completely combust the tail gas in a reformer furnace. Constant flow rate and constant fuel property can be obtained by intelligent mixing designs.