Motivation
The experimental SBH system revealed that thermal management is a critical design constraint at bench scale. Experiments can only measure a few conditions; simulation answers what if questions:
- What if the reactor had an external heat recovery coil?
- What if the purification module were thermally integrated with the reactor?
- What operating conditions minimize thermal stress while maintaining hydrogen output?
Scenarios
Five reactor configurations compared under identical model equations and operating parameters:
- Baseline — no heat recovery (reference)
- Wrap coil (A) — external coil around reactor body, simple retrofit
- Internal coil (B) — coil inside the reactor for direct heat extraction
- Embedded purification (C) — purification module thermally integrated with reactor
- Hybrid (D) — internal coil + embedded purification combined
Results
| Scenario | Peak Temp (°C) | Heat Recovered (%) | Notes |
|---|---|---|---|
| Baseline | *** | 0 | Reference |
| Wrap coil (A) | *** | *** % | Simple retrofit |
| Internal coil (B) | *** | *** % | Most effective cooling |
| Embedded purification (C) | *** | *** % | Heat reuse |
| Hybrid (D) | *** | *** % | Best overall |
Quantitative scenario values withheld pending publication. Relative ranking and qualitative trends are described below.
Findings
- Baseline shows rapid temperature rise that can exceed safe operating limits at high SBH concentrations
- Internal coil provides the most effective peak temperature reduction among individual strategies
- Embedded purification successfully recovers useful heat while slightly reducing reactor cooling effectiveness
- Hybrid achieves the best balance of thermal control and heat utilization, but introduces more complex control requirements
- Temperature rise is most sensitive to hydrogen generation rate during the early phase of operation
- Embedded purification shows mutually beneficial coupling: reaction heat improves CO catalysis efficiency while reducing reactor temperature
Design Implications
- Portable systems prioritizing simplicity: external wrap coil gives meaningful improvement with minimal design change
- Systems prioritizing thermal performance: internal coil is preferred
- Purification-efficiency-critical systems: thermal integration of the purification module is worthwhile
Limitations
- Lumped thermal model does not capture spatial temperature gradients within the reactor
- Catalyst activity degradation over time is not modeled
- Coil heat transfer coefficients estimated from correlations; experimental measurement would improve accuracy
→ Next: CCPP-LOHC Optimization applies the same methodology — parameterized simulation, scenario comparison, performance ranking — at MW-scale industrial integration.