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Organic waste gas VOCs purification series catalysts
1.1.1 The basic principle and purification process of organic waste gas VOCs
The catalytic combustion approach is depended on the catalyst, to treat the organics by low temperature highly efficient, energy saving and environmentally method, so that to realize the purpose of standard discharge. The catalytic combustion reaction is the typical catalytic reaction of gas – solid phase, its essence is that at a certain temperature, occurring catalytic oxidation reaction of the organics (VOCs) which adsorbed on the catalyst surface with oxygen from the air, completely oxidize and decompose to harmless CO2 and H2O, and release reaction heat process. With the catalyst can significantly reduce the ignition temperature of the organic matter, in progress of flameless combustion to reduce the preheat energy consumption and NOx formation.
1.1.2 Low-temperature catalytic combustion process characteristics
Low ignition temperature with self-sustaining operation without external energy supply when reach certain concentration, so can save energy; catalytic combustion compared to the direct combustion relating the organic exhaust gas (please find the below comparison parameters), it has advantage of low ignition temperature, low energy consumption. If rational design, basically can achieve self-sustaining operation without external energy supply.
Combustion Form | Ignition Temperature | Ignition temperature | Combustion State | NOx Generated | Other Harmful Substances |
Catalytic combustion | 200-400°C | 300-500°C | Low-temperature flameless combustion | almost no | Non Benzopyrene, dioxins and other carcinogens |
Thermal combustion | 600-900°C | 600-800°C | Stay in the high-temperature flame | certain amount | Relatively high concentrations of these carcinogens to generate |
1.1.3 Catalyst operation cautionsand maintenance measures
Cautions: In the low temperatures, plenty of organics access into the catalyst bed, cause the catalyst "suffocated", lead to temporarily deactivation, the compounds which contains sulfur, phosphorus, arsenic halogen and heavy metal compounds will react with the active ingredient, leading to the catalyst permanently inactivation; Dust, coke, high-boiling viscous attached to the catalyst surface, covering the catalyst active sites, lead to catalytic loss; High temperature will cause the catalyst carrier and active ingredient reunion or sintered, lead to the active site numbers dramatically reduce, final inactivation.
Maintenance measures:
Low-temperature "suffocate": before normal running, catalyst bed must be pre-heated in the fresh air to reach reaction temperature, until that, organic waste gas is not allowed to lead in;
Get rid of harmful material like sulfur by pre-treatment, or select the corresponding resistance catalysts; Dust, coke, high-boiling viscous: process pre-treatment of removal dust etc.;
Over-temperature: when the catalyst bed temperature exceeds 600 ° C, the system stop running or diluted by fresh air, cooling down.
1.1.4 Applications
As a high efficient low-temperature catalytic oxidation technology, catalytic combustion treatment technology can be applied to the vast majority of combustible organic waste gas treatment process, and the applicable concentration range is wide (200 10000mg/m3), need to concentrate low concentrations of below 1000mg/m3 and need to dilute the concentration of above 10000mg/m3. Specially, the organics in the exhaust is not suitable for recycling or non recycling value, can highly efficient, low-cost processing through the catalytic combustion technology, after purification exhaust gas concentration can less than 100ppm.
Application Industries
Petrochemical industry
Painting Industry
Coating Industry
Other gas, oil, burning oven industries
Environmental protection equipment manufacturing industry
1.1.5 Catalyst Quality Standard and Offer
Generally, the performance of VOCs purification catalyst is required as: low ignition temperature, high conversion rate, the concentration of the exhaust emissions meet the design requirements; high compressive strength; excellent heat resistance and chemical stability; strong adhesion, uniform appearance color; low flow resistances.
Quality standards of V-shaped high activity noble metal VOCs purification catalyst:
Serial No. | Test Items | Technical Specification |
Carrier specifications: cordierite multiple specifications, alumina composite carrier | ||
1 | Space velocity | ≥1×104h-1 |
2 | Ignition temperature | 150°C-300°C |
3 | Best operation temperature | 300°C-500°C |
4 | Waste gas purification rate, service life | ≥90%, 0.5—2 years |
5 | Outlet Waste gas concentration | <100ppm |
6 | Bulk density | 0.68±0.05g/mL |
7 | Crushing strength | ≥14 MPa |
8 | Coating loading | >10.0% |
9 | Active component loading | 0.05%--0.2%(or upon customer requirement) |
10 | Expulsion rate | <1% |
11 | Appearance | Conventional fawn (reduction in gray) |
12 | Package | Moisture-proof and sealed |
13 | Recommended installation height to diameter ratio | Ceramic honeycomb 4:1, particle type: 2:1 |