The Laboratory Waste Gas Treatment System collects, purifies, and treats toxic, harmful, flammable, and explosive gases (such as volatile organic compounds VOCs, acidic gases, alkaline gases, sulfur/nitrogen-containing gases, etc.) generated during laboratory processes, ensuring they meet national emission standards (such as the Comprehensive Emission Standard for Air Pollutants GB 16297) before discharge. This system is crucial for the health of laboratory personnel, the safety of surrounding environments, and environmental compliance, and is widely used in fields such as chemistry, pharmaceuticals, materials, and environmental testing.

Key System Design Standards and Specifications

The laboratory exhaust treatment system must strictly comply with national environmental protection standards (GB 16297, GB 37822 "Control Standard for Unorganized Emission of Volatile Organic Compounds") and industry specifications. The key design points are as follows:

1. Exhaust gas collection design standards

Capture Efficiency: Local exhaust (such as lab bench operations) requires a swivel exhaust hood (inlet air velocity ≥0.5m/s, hood mouth distance from exhaust source ≤30cm), ensuring cabinet exhaust (like fume hoods) maintains a negative pressure within the cabinet (-5~-15Pa), with a capture efficiency ≥90%.

Pipe Design:

Pipe material must be compatible with waste gases (use PP pipes or FRP pipes for acidic waste gases, galvanized steel pipes or stainless steel pipes for organic waste gases, to avoid corrosion or swelling).

Pipe velocity control: Acidic/alkaline waste gas ≤ 15 m/s, VOCs waste gas ≤ 12 m/s (to prevent excessive velocity causing pipe wear or waste gas retention).

Avoid dead ends: Use large-radius elbows (R≥3D, where D is the pipe diameter) at pipe bends, and connect branch pipes to main pipes with 45° offsets.

2. Standard Design for Main Purification Unit

Absorber Tower Design

Filling Material Selection: Polypropylene Pall rings for acidic waste gases, ceramic filling for alkaline waste gases; filling layer height ≥ 1.5m.

Liquid-to-gas ratio: Acidic waste gas treatment liquid-to-gas ratio ≥ 2L/m³, alkaline waste gas ≥ 1.5L/m³.

Design of Activated Carbon Adsorption Tower

Activated Carbon Filling Quantity: Based on the exhaust air volume and concentration, the empty tower flow rate ≤ 0.8 m/s, and residence time ≥ 1.5 s.

Safety Design: The adsorption tower must be equipped with a explosion-proof valve and a CO concentration detector.

Catalytic combustion unit design:

Catalyst Selection: Anti-poisoning catalyst required for treating sulfur/chlorine-containing VOCs; space velocity ≤ 15,000 h⁻¹.

Preheat Temperature: During cold start, the exhaust gas must be preheated to the catalyst ignition temperature, using either electric heating or waste heat recovery heating.

3. Emission and Safety Design Standards

Exhaust pipe requirements: The exhaust pipe must be higher than the laboratory roof by ≥3m, at least 50m away from surrounding sensitive areas, and the exit wind speed must be ≥5m/s.

Monitoring and Alarm

Exhaust outlets must be equipped with online monitoring equipment.

Gas concentration detectors must be set before and after the purification unit, linked with the fan and valves.

Emergency Design: The system must be equipped with bypass pipes.

Section 4: Daily Operations and Security Management

Regular maintenance content

Daily Inspection:

Check the fan operational status.

Check the level of the absorption tower.

View online monitoring data.

Weekly Maintenance:

Clean the filter of the pretreatment unit.

Calibrate gas concentration detectors.

Monthly / Quarterly Maintenance:

Replace activated carbon;

Check catalyst activity.

Clean absorbent tower media.

2. Safety Operating Procedures

Prior to starting the waste gas treatment system, the pretreatment unit must be activated first, followed by the fan, to prevent untreated waste gas from being directly discharged.

When replacing activated carbon/catalyst, protective gear must be worn, and the spent activated carbon/catalyst should be handled as hazardous waste by a qualified unit.

In case of exhaust gas leakage, immediately shut down the equipment, close the exhaust source, activate emergency ventilation, and restart the system after the leakage is eliminated.

Regularly conduct emergency drills to ensure personnel are familiar with shutdown, evacuation, and rescue procedures.

3. Environmental Compliance Requirements

Regularly commission third-party testing agencies to sample and analyze exhaust emissions from the exhaust outlet, issue test reports, and ensure compliance with emission standards.

Establish and maintain an operation and maintenance ledger, retaining it for at least 3 years for environmental inspection purposes.

If there is a significant change in the composition of laboratory exhaust gases or air volume, the treatment process must be reassessed, and the system may need to be modified if necessary, to prevent purification failure due to "mismatch."