pharmaceutical-industry-waste-gas

Pharmaceutical Industry Waste Gas Treatment Process

1. Waste Gas Classification and Collection
- Waste gases are collected according to their properties through dedicated pipelines and gas collection devices:
- Fermentation workshop waste gases (containing NH₃, H₂S, and odors): Collected through a negative pressure hood on the workshop ceiling and connected to the odor treatment system.
- Solvent volatile organic compounds (VOCs): Collected from sources such as reactors, batching tanks, and drying equipment, and connected separately to the organic waste gas treatment system.
- Acid and alkaline waste gases: Collected from local exhaust hoods during the cleaning and neutralization processes, and transported through separate pipelines for acidic (HCl, H₂SO₄) and alkaline (NH₃).
- The fan adjusts the air pressure based on the waste gas flow rate and concentration to prevent mixing reactions between waste gases of different properties (e.g., acid and base mixing to form salts that could clog pipelines).
2. Pretreatment
- Dust filtration: All waste gases first pass through bag filters or high-efficiency filters to remove drug powder and excipient dust to prevent subsequent equipment clogging or catalyst poisoning. - Humidity Control: High-humidity VOCs exhaust (e.g., from the distillation process) is condensed to remove water and reduce humidity to below 60% (to avoid affecting adsorption/catalytic efficiency).
- Temperature Control: High-temperature exhaust (e.g., from drying equipment) is cooled to below 40°C via a heat exchanger to adapt to the operating conditions of subsequent treatment equipment.
3. Core Purification by Separation
- Fermentation Odor Exhaust: A "spray scrubber + biofilter" combination is used. The exhaust first passes through an acidic spray tower (H₂SO₄ solution) to absorb NH₃, then through an alkaline spray tower (NaOH solution) to absorb H₂S. Finally, the exhaust enters the biofilter, where microorganisms degrade any remaining odorous substances.
- VOCs Exhaust:
- Low concentrations (<500 mg/m³): Use an activated carbon adsorption tower (or molecular sieve adsorption). After saturation, the exhaust is desorbed and regenerated using hot air. - Medium-to-high concentrations (>500mg/m³): Adsorption-desorption plus regenerative catalytic combustion (RCO) is used to oxidize VOCs to CO₂ and H₂O, with heat recovered in the thermal storage element to reduce energy consumption.
- Chlorine/sulfur-containing VOCs (such as chloroform): Regenerative thermal combustion (RTO) is used for direct decomposition at high temperatures (800-1000°C) to avoid catalyst poisoning.
- Acidic and alkaline waste gases: Acidic waste gases are absorbed in a NaOH solution spray tower, while alkaline waste gases are absorbed in an H₂SO₄ solution spray tower. The two towers are connected in series to ensure a purification efficiency of >95%.
4. End-of-pipe treatment and discharge
- The purified waste gases are collected, passed through a demister to remove moisture, and then passed through an activated carbon adsorption tower for deep end-of-pipe purification (to control residual odor). The waste gas is ultimately discharged through an exhaust stack ≥15 meters tall. Online monitors (for VOCs, NH₃, H₂S, and particulate matter concentrations) are installed at key locations to ensure compliance with pharmaceutical industry air pollutant emission standards.

The core of this process is "differential treatment + comprehensive odor control." Addressing the complex composition, high volatility, and strong odor of pharmaceutical waste gas, multi-stage purification is employed to achieve both compliance with emission standards and workplace environmental improvement, while also adapting to fluctuating waste gas concentrations during intermittent production.