High - efficiency capture and low - resistance operation technology of oil fume purifiers —— The evo

Background Overview: Pollution Characteristics and Treatment Needs of Restaurant Fumes

Restaurant fumes (mainly composed of PM2.5 particles and volatile organic compounds (VOCs) such as aldehydes and hydrocarbons) are a significant source of urban air pollution (accounting for 10%-15% of total PM2.5). Their emissions are characterized by high temperature (60-100℃), high humidity (5%-15% moisture content), and complex composition (particle size 0.1-10μm, over 100 types of VOCs). Traditional purification technologies (such as single mechanical filtration and single electrostatic dust removal) suffer from limitations in efficiency (PM2.5 removal rate <80%, VOCs removal rate <50%), clogging (oil adhesion leading to increased resistance), and secondary pollution (ozone generation). The industry is upgrading to "multi-stage composite purification," aiming to achieve "highly efficient capture (PM2.5 ≥95%) + low-resistance operation (resistance <150Pa) + no secondary pollution" through the synergistic effect of "front-end interception + deep oxidation."

Core Technology Analysis: The Synergistic Mechanism of the Composite Purification Module

1. Front-end mechanical filtration: interception of large particles and pretreatment

It uses a stainless steel/aluminum alloy metal filter (pore size 1-5mm) or a ceramic corrugated plate to preferentially intercept large oil droplets (particle size > 5μm, accounting for about 30%-40%) in the cooking fumes, reducing the load on subsequent modules. Features: low resistance (<50Pa), easy to clean (can be rinsed with a high-pressure water gun periodically), but ineffective against fine particles (PM2.5) and VOCs.

2. Mid-range electrostatic precipitator: captures fine particles and reacts with charged oxidation.

Oil fume particles are charged (positive/negative charge) using a high-voltage electric field (5-10kV) and deposited on an anisotropic electrode plate (dust collecting electrode). (Efficiency is positively correlated with particle size: removal rate of 1μm particles >90%, efficiency drops to 70% for 0.1μm particles). Optimization directions include:

• ● electrode materialMade of aluminum alloy (good conductivity) or stainless steel (corrosion resistant), with an oleophobic coating on the surface (to reduce oil adhesion);

  
  

• ● Electric field distributionHoneycomb or plate-wire structure (electric field uniformity > 90%) to avoid ozone generation from partial discharge (concentration < 0.1 mg/m³).

  
  

• ● Synergistic oxidationA small amount of ozone is introduced into an electric field (or ozone is generated by high-voltage discharge) to oxidize some VOCs (such as formaldehyde) into CO₂ and H₂O.

  
  

3. Back-end adsorption/catalysis: Deep treatment of VOCs and odors

It uses activated carbon fiber (specific surface area > 1000 m²/g) or catalysts supported on precious metals (such as Pt/Pd) to adsorb residual VOCs (such as benzene compounds) and decompose them through catalytic combustion (temperature 200-300℃). Features: Ineffective against PM2.5, but can remove over 90% of odors and low-concentration VOCs. The adsorption material needs to be replaced regularly (usually every 3-6 months).

Current Status and Trends of Industry Applications

Currently, high-end kitchen fume purifiers (used in large commercial kitchens and urban complexes) are generally equipped with a three-stage composite system of "mechanical filtration + electrostatic dust removal + catalytic oxidation" (PM2.5 removal rate > 95%, VOCs removal rate > 85%, resistance < 150Pa). Mid-range models (small and medium-sized restaurants) mainly use "electrostatic dust removal + simple filtration" (PM2.5 removal rate 80%-90%). Market data shows that the initial investment cost of composite purification equipment is 20%-30% higher than that of single technology, but the maintenance cycle is extended (from once a month to once a quarter), resulting in a lower overall TCO (Total Cost of Ownership). Future trends include: intelligent monitoring (real-time display of PM2.5/VOCs concentration and filter life), low-temperature plasma synergistic technology (high-efficiency oxidation without ozone generation), and the development of dedicated modules for Chinese stir-fry fumes (high instantaneous particulate concentration).