Views: 0 Author: QT Publish Time: 2025-07-22 Origin: QT
In the refining world, downtime isn’t just inconvenient—it’s expensive. And few things contribute more silently to process inefficiency than a deactivated zeolite catalyst.
Over the years, we’ve supported dozens of refining clients—especially those working with ZSM-5, MCM-22, and ZSM-48 catalysts—who struggled to catch the signs of deactivation early enough. By the time pressure drops or selectivity changes appear in the control room, it’s often too late.
But the warning signs are there—if you know what to look for.
One of the most common early indicators is a gradual pressure build-up across the reactor bed. This usually signals pore blockage caused by coke deposition inside the zeolite’s microchannels.
According to Zhang et al. (Fuel Processing Tech, 2015), over 80% of deactivation in methanol-to-olefins (MTO) processes is linked to pore occlusion from carbonaceous buildup—particularly in ZSM-5.
If your pressure differential begins rising while feedstock flow and temperature remain constant, it’s time to investigate. A small increase of 0.1 MPa could reflect a 20–30% loss in active surface area.
Switch to zeolites with more uniform mesoporosity (like MCM-22) to delay coke accumulation. We're currently testing coke resistance across 3 zeolite types—results coming soon.
Has your product slate changed lately—say, a drop in light olefins or an unexpected spike in aromatics?
Deactivation doesn't just reduce activity—it often changes selectivity patterns due to acid site loss or altered pore environment. The silicon-to-aluminum ratio (Si/Al) plays a key role here.
A 2023 Chemical Science paper showed that fluctuations in the Si/Al ratio as small as ±2 units can shift product selectivity by over 10%, especially in aromatization reactions.
When your ZSM-5 catalyst’s Si/Al ratio isn’t tightly controlled, you may see heavier hydrocarbon chains, more cracking residue, or less propylene/ethylene yield.
We calibrate every batch using XRD and NH₃-TPD to ensure consistent acid site density. After our next factory inspection, we’ll publish full traceability reports for each catalyst model.
It may sound basic, but visual inspection of the spent catalyst can reveal a lot.
Dark grey to black → typical carbon deposition
Pale white or blueish → possible contamination (e.g. Na⁺ or heavy metal poisoning)
Patchy discoloration → uneven reactor loading or poor temperature distribution
Our in-house SEM-EDX scans have shown clear links between dark carbon bands and localized hot spots in pilot reactors.
If your regenerated catalyst doesn’t return to its original tan or ivory shade, it may have suffered structural collapse—especially if it was exposed to high steam temperatures or water vapor during regeneration.
Catalyst deactivation isn’t just a question of how long—but how predictably the material ages.
Our experience shows:
| Zeolite Type | Typical Deactivation Mode | Comments |
| ZSM-5 | Coke buildup in micropores | High shape selectivity, moderate lifespan |
| MCM-22 | Slower deactivation, more stable acidity | Better coke resistance |
| ZSM-48 | Sensitive to water vapor & steam cycles | Requires tighter process control |
We’re currently compiling a full regeneration lifespan comparison (across 300h pilot tests). Stay tuned for lab-based performance curves.
A: It depends on feedstock composition and reactor design. Typically, ZSM-5 and MCM-22 catalysts are regenerated every 30–90 days, but signs like ΔP or selectivity loss are more accurate triggers.
A: High-quality zeolites can withstand 5–10 full regenerations if handled properly. Performance drop-off accelerates if exposed to wet or impure regeneration gases.
Catching catalyst deactivation early is both a science and an art. It takes experience—and the right technical support.
At Yutai Zeolite, we don’t just manufacture catalysts—we work with engineers and lab teams to match the right zeolite to the right process. Whether you're troubleshooting a propylene yield drop or designing your next regeneration cycle, we can help.
Need help analyzing a deactivated sample or choosing the right Si/Al ratio? Contact our technical team—we reply within 24h.
Zhang, S. et al. Coke formation on H-ZSM-5, Fuel Processing Technology, 2015
RSC Chemical Science, Regulating Si/Al ratios in zeolites, 2023
Internal data: Yutai SEM-EDX scans, 2024 Q1
