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Choosing the Right Packed Bed and Bubbling Wet Scrubbers for Chemical Tank Ventilation

Author: Michael Klepik, Chief Executive Officer

"Hello everyone, Michael Klepik here! Today, we’ll be discussing the critical process of selecting ventilation scrubbers (specifically packed bed scrubbers with Pall rings and other packing media) and bubbling systems for chemical tanks. These systems play a key role in capturing harmful fumes, such as acid vapors, and maintaining workplace safety while ensuring compliance with environmental regulations. Let’s dive into the selection process and the logic behind choosing the right equipment for your application."

Packed Bed Wet Scrubbers for Chemical Tank Ventilation

Packed bed scrubbers are commonly used for capturing and neutralizing chemical fumes generated during tank operations. They are highly effective at treating acid vapors, solvents, and other hazardous emissions.

TORNADO-FB Fluidized Bed Scrubber

Key Components of a Packed Bed Scrubber

Packing Media:

Pall Rings: Offer high surface area for gas-liquid interaction and low-pressure drop, making them suitable for high-efficiency scrubbing.
Saddle Packing: Improves liquid distribution, minimizing clogging and ensuring uniform gas-liquid contact.
Other Media: Structured packing or Intalox saddles for specialized applications requiring higher efficiency.

Spray System:
Delivers scrubbing liquid (e.g., water, alkaline solutions) over the packing media to capture contaminants from the gas stream.

Droplet Separators:
Prevent moisture carryover into the exhaust by capturing liquid droplets before the air exits the scrubber.

Logic Behind Scrubber Selection

Chemical Properties:

Type of Chemical: Identify the vapor type (e.g., sulfuric acid, hydrochloric acid).
Reactivity: Choose scrubbing liquids that neutralize the chemical fumes effectively.

Flow Requirements:

Determine the air flow rate (ACFM) from the tank to size the scrubber.
Example: If the inlet flow is 1120 ACFM, you’ll need a scrubber that handles at least this volume without exceeding its operational limits.

Temperature and Material Compatibility:

Use PVC, CPVC, or PVDF for low to medium temperatures and acidic conditions.
For high temperatures or aggressive chemicals, opt for FRP, Hastelloy, or Titanium.

System Design:

Height-to-Diameter Ratio: Ensure enough contact time for gas-liquid interaction.
Pressure Drop: Select packing media and liquid flow rates that minimize resistance while maintaining efficiency.

Bubbling Wet Scrubbers (Bubblers) for Tank Aspiration

Bubblers are ideal for tanks emitting light vapors or fumes that require moderate scrubbing. They involve introducing an airflow at the base of the tank, which passes through a scrubbing liquid (often water or alkaline solutions).

Key Components of a Bubbling Wet Scrubbers

Bubbler plates or diffusers evenly distribute air through the scrubbing liquid for effective neutralization.
The scrubbing liquid absorbs or neutralizes fumes, depending on the chemical being aspirated (e.g., an alkaline solution for acidic fumes).
The exhaust outlet ensures that treated air exits the system efficiently while maintaining airflow balance.

Logic Behind Bubbling Wet Scrubbers Selection

1. Tank Size and Airflow:

Match the system to the tank’s dimensions and ventilation requirements.
Example: A tank with a 2-inch inlet pipe and 910 ACFM requires a 6-inch vent capable of handling 970 ACFM.

2. Chemical Compatibility:

Use non-corrosive materials like PP, PVC, or HDPE for acidic fumes.
Ensure the scrubbing liquid is compatible with the chemicals being treated.

3. Operating Conditions:

Monitor the pH and temperature of the scrubbing liquid to maintain efficiency.
Consider automation for liquid replenishment and pH adjustments.

TYPHOON Tray Scrubber

Tank Ventilation Sizing Table

Here’s a practical guide to matching vent and inlet sizes to airflow requirements:

Hose Size (inches)	Inlet Pipe Size (inches)	Inlet Flow (ACFM)	Min. Vent Size (inches)	Vent Flow (ACFM)
1	1	180	4	380
2	1	190	4	380
2	2	910	6	970
3	2	1120	8	1780
3	3	2250	10	2935
4	3	3500	12	4600
5	4	5000	14	6500
6	5	7000	16	8500
8	6	10000	20	12000

Tank Vent Requirements

Explanation of Vent Diameter and Flow Logic

Flow Dynamics — Vent size is proportional to the airflow (ACFM). Larger vents accommodate higher flows while minimizing backpressure and resistance.
Pipe and Hose Interaction — The hose and pipe size affect frictional losses and pressure drops. Larger inlet pipes support greater flow rates with reduced turbulence.
Safety Margins — Vent flow (ACFM) is always higher than inlet flow to handle expelled air and ensure efficient fume removal.
Scalability — Larger vent sizes (e.g., 6", 8") are introduced for industrial applications requiring greater air displacement.

Choosing Between Systems

Packed Bed Scrubber	Bubbling System
Best for high-flow, aggressive chemical fumes requiring thorough neutralization.	Ideal for smaller tanks or moderate fume volumes.
Use when precise pH control and high-efficiency scrubbing are critical.	Cost-effective for simpler applications with manageable chemical emissions.

TORNADO RP Vertical Wet Scrubber

Performance: 600 — 24 000 cfm

TYPHOON Tray Tower Scrubber

Performance: 100 — 175 000 cfm

BOREAS-P3 Horizontal Packed Bed Scrubber

Performance:
100 — 175 000 cfm

Tank Vent Scrubber

Performance: 0 — 3 000 cfm

Conclusion

"Selecting the right ventilation Packed scrubber or bubbling Wet Scrubbers depends on your tank’s airflow, the type of chemicals involved, and operational conditions. At Torch-Air, we specialize in custom-designed scrubbers and bubbling systems tailored to your exact needs. Contact us to find the perfect solution for safe and efficient tank ventilation. Until next time, keep your systems running clean and your operations compliant!"

Repair and Replacement of Scrubbers for HCL Tanks | Effective Emission Control

Discover how we repaired and upgraded HCL tank scrubbers, improving emission control, odor elimination, and air purification for lasting performance.

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We always perform precise calculations and offer expert assistance in selecting the optimal dust collection or gas cleaning systems, typically completing this process within 1 to 2 days

Head of Engineering,
Vladimir Nikulin

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