1. Basic Definition of VOCs Catalyst

VOCs oxidation catalyst (VOCs catalyst for short) is a core functional material applied in catalytic combustion (CO) and regenerative catalytic oxidation (RCO) systems. It can lower the complete oxidation temperature of volatile organic compounds, degrade VOCs into harmless carbon dioxide and water at low–medium temperature, and eliminate malodorous gas, waste gas pollution without secondary pollution.

VOCs cover industrial waste gas such as benzene, esters, ketones, alcohols, aldehydes, hydrocarbons and halogenated organics from coatings, printing, chemical, pharmaceutical, rubber and packaging industries. Catalysts break their molecular structure via catalytic oxidation instead of direct high-temperature incineration, cutting energy consumption significantly.

2. Two Main Classifications of VOCs Catalysts

2.1 Precious Metal Catalysts (Mainstream Industrial Type)

Active components: Platinum (Pt), Palladium (Pd), binary Pt-Pd composite active components

Carrier: Cordierite honeycomb ceramic carrier coated with alumina washcoat

Core Advantages

1. Ultra-low light-off temperature: Start catalytic decomposition at 180–250 ℃, full conversion above 280 ℃
2. High catalytic activity, wide adaptability to mixed VOC waste gas
3. Stable conversion efficiency, high anti-toxicity against conventional organic waste gas

Typical Application

Coating waste gas, printing ink waste gas, packaging adhesive waste gas, food processing malodor treatment

2.2 Non-Precious Metal Catalysts (Manganese-Copper Series, Rare Earth Composite)

Active components: Mn, Cu, Co, Ce rare earth composite metal oxides

Core Advantages

1. Low raw material cost, no precious metal resource dependence
2. Good resistance to high temperature, resistant to frequent temperature fluctuation

Limitations

Higher light-off temperature (260–350 ℃), weaker activity for low-concentration waste gas

Typical Application

High-temperature industrial waste gas, large-volume low-value waste gas with strict cost budgets

3. Core Catalytic Reaction Mechanism

1. VOC gas molecules are adsorbed on the catalyst surface active sites;
2. Lattice oxygen on metal active components oxidizes organic molecular chains, breaking C-C, C-H bonds;
3. Organic matter is fully oxidized into CO₂ and H₂O;
4. Air oxygen replenishes consumed lattice oxygen, realizing cyclic continuous catalytic reaction.

Reaction general formula:

C_x​H_y​O_z​+(x+y​/4−z​/2)O_2​>>>Catalyst​x>>>CO_2​+y/2​H_2​O

4. Key Performance Technical Indicators of Qualified VOCs Oxidation Catalyst

1. Light-off temperature (T50): Temperature when VOC removal efficiency reaches 50%
2. Complete conversion temperature (T99): Temperature when removal rate ≥99% (core index)
3. Heat resistance temperature: Long-term stable working temperature, general 600–800 ℃
4. Anti-toxic performance: Tolerance to trace sulfur, dust, silicone oil in waste gas
5. Service life: Precious metal catalyst 12,000–24,000 hours; non-precious metal 8,000–15,000 hours
6. Honeycomb carrier parameters: Cell density 100/200/300 cpsi, low air resistance

5. Complete Production Structure of VOCs Catalyst

1. Substrate: Cordierite honeycomb ceramic (low thermal expansion, high mechanical strength)
2. Washcoat layer: High-specific-surface-area γ-Al₂O₃, load rare earth additives to stabilize active components
3. Active layer: Precious metal Pt/Pd or composite metal oxide active ingredients
4. Auxiliary additives: Cerium, lanthanum rare earth to improve anti-sintering and anti-poisoning capacity

6. Main Industrial Application Scenarios

1. Coating industry: Automobile painting, furniture spraying, hardware surface coating waste gas
2. Printing industry: Gravure printing, flexo printing ink solvent waste gas
3. Fine chemical & pharmaceutical: Alcohol, ketone, aldehyde waste gas from synthesis workshop
4. Packaging & synthetic material: Plastic film, adhesive, composite material waste gas
5. Rubber, leather, textile printing and dyeing malodor and organic waste gas
6. Food processing, tobacco, sewage station odor purification

7. Advantages of Catalytic Oxidation with VOCs Catalyst vs Direct Incineration

1. Low operating temperature, fuel consumption reduced by 60%–80%, lower operation cost
2. No open flame, high safety, suitable for flammable and explosive organic waste gas
3. Complete degradation rate ≥99%, reach national industrial waste gas emission standards
4. No NOₓ thermal nitrogen oxide byproducts, lower secondary pollution risk
5. Small equipment footprint, easy to match RCO/CO waste gas treatment equipment

8. Common Catalyst Poisoning & Protection Methods

Main Toxic Substances

• Silicone oil, silicon compounds: Form silica covering active sites, permanent deactivation
• Sulfur compounds (H₂S, mercaptan): Generate metal sulfide to block activity
• Heavy metal dust, tar, viscous polymer: Physical coverage of catalyst surface

Protection Solutions

Install front dust filter, activated carbon adsorption tower, desulfurization pretreatment device before catalyst reactor to intercept toxic substances.

9. Selection Guide for Different Working Conditions

1. Low-concentration, low-temperature waste gas (spray booth): Pt-Pd precious metal catalyst (T99 ≤280 ℃)
2. High-temperature large-air-volume waste gas, cost priority: Mn-Ce non-precious metal composite catalyst
3. Waste gas containing trace sulfur, long-term operation: Rare earth modified high anti-poison precious metal catalyst
4. High silicone oil waste gas: Increase multi-stage pretreatment, use silicon-resistant customized catalyst