catalysts used in fire suppression tanks
In the fire suppression tanks of catalyst-assisted fire suppression equipment, the commonly used catalysts are mainly designed for functions such as decomposition of harmful gases, enhancement of flame retardancy, and purification of residual substances after fire suppression. The specific types and characteristics are as follows:
I. Core Catalytic Function and Corresponding Catalyst Types
1. Toxic Gas Decomposition Catalyst (The Most Core Application)
Function: Rapidly decompose the toxic gases (such as ozone, carbon monoxide, formaldehyde, etc.) produced during a fire, reducing secondary hazards.
Manganese dioxide (MnO₂) based catalysts
Form: Granular or honeycomb-like, often loaded on activated carbon or alumina carriers (specific surface area ≥ 300 m²/g).
Characteristics: Can efficiently decompose ozone (O₃ → O₂) at room temperature, with a decomposition efficiency > 99%, humidity resistance range 50%-80%, suitable for electrical fire scenarios with ozone.
Copper oxide - iron oxide composite catalyst (CuO-Fe₂O₃)
Active sites: Nano-sized metal oxide particles (particle size 5-10 nm), catalyzing the oxidation of carbon monoxide (CO) to carbon dioxide through a synergistic effect, with an ignition temperature as low as 80°C, suitable for gas purification after fires in confined spaces.
2. Fire extinguishing agent residue degradation catalyst
Function: Decomposes halogenated alkanes, halons and other ozone-depleting substances remaining after fire extinguishing to reduce environmental pollution.
Precious metal-loaded molecular sieves (Pt/ZSM-5, Pd/13X)
Active components: 0.5% - 1% of platinum (Pt) or palladium (Pd) nanoparticles, dispersed within the micropores of the molecular sieves (pore size 0.5 - 1 nm).
Function: Catalytically decompose halogenated alkanes (e.g., CCl₄ → CO₂ + HCl) at 150 - 250°C, with a degradation rate > 95%, suitable for environmental treatment after the fire suppression of precision instruments.
II. Key points of catalyst application design
Anti-poisoning and stability
It needs to withstand high temperatures (short-term temperature resistance > 500°C, such as fire thermal shock) and gas corrosion (such as SO₂, HCl), usually adding rare earth elements (Ce, La) as additives to enhance the ability to resist sulfur and chlorine poisoning.
Gas flow compatibility
The catalyst bed is designed as a multi-layer honeycomb structure (porosity > 70%), ensuring uniform gas flow rate (recommended space velocity 10,000 - 30,000 h⁻¹), avoiding local overheating or short flow.
Synergistic fire suppression design When used in conjunction with a foam fire suppression system: The catalyst bed is placed at the rear end of the foam generator. First, the fire is extinguished by the foam coverage, and then the residual gas is decomposed by the catalyst, forming a dual barrier of "physical fire suppression and chemical purification".
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