grinding-polishing-and-welding

Exhaust gas from grinding, polishing, and welding workshops has a complex composition, including dust (metallic and non-metallic particles), welding fume (metal oxides, hazardous gases such as ozone and nitrogen oxides), and small amounts of VOCs (such as coolant volatiles). Therefore, the treatment process must be designed to address the dual needs of "dust removal and degassing." A typical process is as follows:

I. Pretreatment Stage (for dust and large particles)

1. Gas Collection System

Unidirectional suction arms, side hoods, or top hoods installed within the workshop precisely capture exhaust gas generated by the grinding/welding stations (especially welding fume, which has a narrow diffusion range and requires close collection). The exhaust is then piped to the treatment system.

2. Primary Dust Removal

If dust concentration is high (such as during the grinding process), it is first removed through a cyclone dust collector or inertial separator to remove large particles ≥10μm, reducing the load on subsequent equipment.

If the primary concentration is fine particles (such as welding fume), the exhaust can be directly transferred to the next stage.

II. Deep Purification Stage (Targeting Fine Particulate Matter and Harmful Gases)
3. High-Efficiency Dust Removal
- Core Equipment: Cartridge Dust Collector (suitable for metal dust, filtration efficiency ≥99%) or Bag Dust Collector (suitable for high-temperature dust, with improved temperature resistance) to remove fine particulate matter ≤1μm (such as metal aerosols in welding fumes).
4. Hazardous Gas Treatment
- If the exhaust contains nitrogen oxides and ozone generated by welding, or small amounts of VOCs emitted by coolants, an activated carbon adsorption chamber (to absorb organic components) or a UV photolysis/plasma purifier (to decompose ozone and small-molecule VOCs) may be required.
- If the exhaust gas contains acidic components (such as oxidizing gases during welding), a spray tower (to neutralize with an alkaline solution) may be added.

III. Discharge Stage
5. Fan and Chimney
The purified gas is lifted by an induced draft fan to a high-altitude discharge (the chimney height must meet local environmental protection requirements) to ensure that the emission concentration meets the standard (e.g., particulate matter ≤10mg/m³, VOCs ≤50mg/m³).

Key Design Points
- Zoned Treatment: The exhaust gas characteristics of the grinding and welding areas differ (grinding produces high levels of dust, while welding fume is fine and contains gases). Separate gas collection systems can be installed, allowing for combined treatment to enhance targeted efficiency.
- Equipment Compatibility: Select equipment specifications based on the workshop air volume (e.g., 1000-5000 m³/h, depending on workshop size) to ensure appropriate air velocity (to avoid dust settling or inadequate adsorption).
- Regular Maintenance: Filter cartridges and bags require regular cleaning or replacement, and activated carbon should be replaced promptly to avoid saturation and ensure long-term treatment efficiency.

This process, through a "dust removal first, gas removal second" tiered treatment process, effectively purifies workshop exhaust gas, meeting environmental emission requirements while improving the workshop working environment.