This functional sulfur recovery catalyst is engineered for Claus Sulfur Recovery Units (SRUs) facing chronic or intermittent trace oxygen ingress. It integrates standard Claus catalytic activity with an advanced oxygen-scavenging mechanism, consuming residual O2 in the upper catalyst bed to prevent sulfate-induced deactivation of downstream conventional catalysts.
Formulated on an activated alumina carrier (Al2O3 >= 80%) with functional metal oxide additives (Fe2O3 >= 6%), this catalyst is designed for staged loading as an upper protective layer within existing converters, eliminating the capital expenditure of a separate deoxygenation reactor vessel.
Key Technical Specifications
|
Parameter |
Typical Specification |
|
Catalyst Type |
Oxygen-scavenging Claus sulfur recovery catalyst |
|
Main Carrier / Component |
Activated Al2O3 (>= 80%) |
|
Functional Additive |
Fe2O3 (>= 6%) |
|
Shape & Size |
Sphere / Strip, Phi 4–6 mm |
|
Color |
Red-brown |
|
Bulk Density |
0.70–0.90 g/mL |
|
Specific Surface Area |
>= 260 m2/g |
|
Crushing Strength |
>= 130 N |
|
Wear Rate |
<= 0.3% |
Application Scope & Selection Criteria
Typical Industrial Applications
Refinery SRUs: Processing acid gas streams derived from amine regeneration units (ARU) and sour water strippers (SWS) where minor air leakage occurs.
Natural Gas Sweetening Plants: Handling high-H2S acid gas with variable feed compositions and flow rates.
Coal Chemical & Syngas Plants: Gasification-associated sulfur recovery units prone to feed fluctuation and catalyst instability.
When to Select This Catalyst over Conventional Alternatives
Evaluate this oxygen-capture catalyst when your operational data indicates:
Trace oxygen is detected or suspected in the acid gas or air-demand control loop.
Conventional catalysts experience accelerated deactivation or recurring sulfate fouling.
Sulfur conversion degrades prematurely during standard operating cycles.
You require protection for downstream TiO2 or alumina beds without investing in upstream deoxygenation units.
Health, Safety & Environment (HSE) Guidelines
Material Properties & Toxicity: This product is a non-flammable, non-explosive solid particle with stable chemical properties under normal temperature and pressure.
Handling & Protection Recommendations:
Dust Protection: Due to the activated alumina and metal oxide components, operators are advised to wear certified dust masks (N95 or equivalent), safety goggles, and wear-resistant gloves during loading and unloading to prevent dust inhalation.
Waste Disposal: Disposal of spent catalysts must comply with local environmental regulations. Spent alumina-based catalyst beads that are not heavily contaminated with restricted heavy metals can typically be handled as general industrial solid waste or handed over to qualified professional units for valuable metal recovery.
Reaction Mechanism & Chemistry
In Claus sulfur recovery units, trace oxygen (O2) entering the reactor undergoes side reactions with active sites and sulfides, leading to sulfate poisoning and the deactivation of conventional alumina or titania catalysts. This product utilizes a unique iron-based functional additive (Fe2O3 >= 6%) to establish an efficient oxygen-scavenging and targeted consumption micro-reaction zone in the upper catalyst bed:
Catalytic Deoxygenation: Within standard Claus operating temperature ranges (200°C to 350°C), it selectively catalyzes the preferential reaction between residual oxygen and trace reducing agents in the acid gas (such as H2S or CO), rapidly consuming free O2:
2H2S + O2 -> 2S + 2H2O
Prevention of Sulfation: By achieving in-situ deoxygenation in the front-end upper bed, the SOx formation pathway is completely interrupted, effectively shielding the active sites of downstream core Claus catalysts from sulfate attack at the source.
Manufacturing, Quality Control & Performance Evidence
Production & Testing Integrity
Xunda operates three dedicated catalyst production lines with an annual capacity of approximately 9,500 tonnes. Each batch undergoes strict quality control testing for:
- Specific surface area (BET)
- Pore size distribution and pore volume
- Single-pellet crushing strength (>= 130 N)
- Attrition loss and wear rate (<= 0.3%)
Commercial Performance Insights
Evaluated across multiple commercial sulfur recovery units, this product effectively maintains bed activity under fluctuating feed conditions. In equivalent industrial comparative assessments, Xunda has observed an approximate 1.7% increase in overall sulfur conversion when utilizing the dual-layer oxygen-capture configuration compared to unprotected conventional beds facing chronic low-level oxygen ingress.
Handling, Loading & Spent Catalyst Management
Handling & Storage
Shipped in moisture-resistant steel drums or flexible intermediate bulk containers (FIBC / jumbo bags).
Store in dry conditions; minimize handling drops to prevent pellet breakage and dust generation during reactor loading.
Regeneration & Replacement Considerations
Bed Longevity: By absorbing initial oxidative stress and sulfate formation in the top layer, this protective catalyst shields the expensive downstream catalyst inventory, extending overall turnaround intervals.
Selective Replacement: During plant turnarounds, plant operators can inspect or replace solely the top protective layer if localized sulfate accumulation reaches capacity, reducing catalyst replacement expenditure.
FAQ
Q: What is the recommended operating temperature range for this oxygen-capture catalyst?
A: The catalyst operates effectively within standard Claus converter temperature ranges, typically between 200°C and 350°C. The exothermic reaction of trace oxygen consumption in the upper layer does not cause localized overheating that would compromise bed integrity, provided that inlet oxygen concentrations remain within typical industrial trace limits (generally below 0.5 vol%).
Q: Can this catalyst be loaded directly on top of existing titanium dioxide (TiO2) or activated alumina beds without changing internal reactor hardware?
A: Yes. The catalyst is specifically sized and shaped (such as 4 to 6 mm spheres or strips) to be directly loaded onto existing catalyst beds. No modification to reactor internals, gas distributors, or piping is required, making it ideal for plant turnarounds and quick retrofits.
Q: How does the oxygen-scavenging layer affect the pressure drop across the Claus converter?
A: Because the catalyst utilizes a high-strength, uniform spherical or strip geometry with a controlled bulk density (0.70 to 0.90 g/mL) and low wear rate (<= 0.3%), it maintains stable void fractions. When replacing an equivalent volume of standard top-layer alumina, the impact on overall reactor pressure drop is negligible.
Q: Does the catalyst require any special pre-activation, drying, or sulfiding procedures during startup?
A: Standard industrial heating and drying procedures for Claus catalysts apply. The catalyst does not require complex ex-situ or in-situ sulfiding gases prior to startup. Normal reactor heat-up under inert gas or process gas flow per standard SRU operating manuals is sufficient to achieve full catalytic and scavenging activity.
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