Membrane Reformer Hydrogen Production with Countercurrent Sweep
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Solution Overview
Problem
Conventional steam methane reforming (SMR) for hydrogen production is inefficient when scaled down, as it relies on waste heat utilization which is often dissipated, leading to increased energy consumption and reduced efficiency.
Innovation Solution
A membrane reformer system using hydrogen-selective membranes and a catalytic membrane reactor that operates at lower temperatures and pressures, facilitating efficient hydrogen production and CO2 capture, with a sweep gas flow countercurrent to the reactants to enhance hydrogen permeation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional steam methane reforming is scaled down, then hydrogen production capacity is reduced, but energy consumption increases and efficiency decreases due to waste heat dissipation
Solution Approach 1:
The patent combines the steam methane reforming reaction and hydrogen separation through membrane permeation into a single integrated membrane reactor system. This merging allows the endothermic reforming reaction to occur within the reactor while simultaneously separating hydrogen through the membrane wall, eliminating the need for separate heat management systems and maintaining efficiency at scaled-down capacities.
Solution Approach 2:
The membrane reactor wall acts as an intermediary that serves dual functions: it conducts heat from the exothermic oxidation side to the endothermic reforming side, and simultaneously separates hydrogen through selective permeation. This intermediary structure enables efficient heat transfer and hydrogen recovery without requiring external heat management infrastructure.
2Productivity
If conventional steam methane reforming is scaled down, then hydrogen production capacity is reduced, but efficiency decreases due to waste heat dissipation
Solution Approach 1:
The patent merges the reforming reaction zone and oxidation zone within a single membrane reactor, allowing waste heat from the exothermic oxidation to be directly utilized by the endothermic reforming reaction through the membrane wall, thereby eliminating waste heat dissipation even at small scale.
Solution Approach 2:
The membrane reactor system is self-sufficient in heat management, where the exothermic oxidation reaction automatically provides the necessary heat for the endothermic reforming reaction through thermal conduction across the membrane wall, eliminating the need for external heat sources or waste heat recovery systems.
3Productivity
If hydrogen is produced through conventional reforming, then large scale production is achieved, but hydrogen separation and purification require additional complex steps
Solution Approach 1:
The patent combines reaction and separation functions into a single membrane reactor unit, where hydrogen is produced and separated simultaneously through the membrane wall. This eliminates the need for downstream separation and purification equipment, reducing device complexity while maintaining large-scale production capability.
Solution Approach 2:
The membrane reactor extracts hydrogen selectively from the reformate gas stream through the membrane wall during the reaction process itself, removing the need for subsequent separation steps. This extraction occurs in-situ within the reactor, simplifying the overall process configuration.
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 membrane reformer achieves higher hydrogen yield and purity, reduces capital and operating costs, and allows for compact, efficient hydrogen production, even at smaller scales, while enabling CO2 capture and utilization.
Implementation Method 1
the tubular membrane in the feed conduit to diffuse the hydrogen from the region through the tubular membrane to a bore of the tubular membrane
Implementation Method 2
catalyst (including steam-reforming catalyst) disposed in the region in the feed conduit external to the tubular membrane to convert the hydrocarbon into hydrogen and carbon dioxide
Implementation Method 3
converting the hydrocarbon to hydrogen and carbon dioxide via catalyst (including steam-reforming catalyst)
Implementation Method 4
flowing a sweep gas through the respective bores to displace hydrogen in a direction countercurrent to flow of hydrocarbon and steam external to the tubular membranes
Data Source
AI summary
A system and method for producing hydrogen from hydrocarbon and steam, including a membrane reformer with multiple membrane reactors each having a tubular membrane. The bore of the tubular membrane is the permeate side for the hydrogen. The region external to the tubular membrane is the retentate side for carbon dioxide. A sweep gas flows through the bore to displace hydrogen in a direction countercurrent to flow of hydrocarbon and steam in the region external to the tubular membrane. The method includes discharging hydrogen as permeate with the sweep gas from the bore, and discharging carbon dioxide in the region external to the tubular membrane as retentate from the membrane reactor.