Industrial Air Pollution Control Glossary

Short, clear definitions of the technical terms used most in industrial air pollution control. Each term links to the relevant DUCON product or tool page, so you can move from a term to the right solution quickly.

Dust Collection Terms

Baghouse (Fabric Filter)

A system that captures dust dry on the surface of woven filter bags, reaching up to 99.9% efficiency including PM10/PM2.5. See baghouse filters.

Jet-Pulse (Pulse-Jet) Cleaning

An online cleaning method that fires a fraction-of-a-second burst of 6-7 bar compressed air into the bags to drop the accumulated dust cake without stopping production.

Cartridge Dust Collector

A compact unit that packs high filter area into pleated cartridge media; ideal for fine dust, welding fume, and tight spaces. See cartridge dust collector.

Electrostatic Precipitator (ESP)

Charges dust in an electric field and collects it on plates; offers low pressure drop at very high flow and temperature, but may not reach the low emissions of a baghouse on very fine particulate.

Cyclone Separator

A pre-separator that spins the gas to throw coarse particulate out by centrifugal force; typically used ahead of a filter as a first stage.

Flat-Bag (Envelope) Filter

A compact baghouse variant using flat/envelope bag elements to pack high filter area per volume; preferred for retrofits and tight spaces. See flat-bag filter.

Gas Cleaning Terms

Wet Scrubber

Contacts the gas with a liquid to remove both particulate and soluble/acid gases; available in venturi, packed-bed, spray-tower, and dynamic types. See wet scrubbers.

Venturi Scrubber

Accelerates the gas through a narrowing throat and impacts it with water for high efficiency on fine particulate (PM2.5). See venturi scrubber.

DeSOx / Flue-Gas Desulfurization (FGD)

Neutralizes sulfur dioxide (SO2) in flue gas with an alkaline sorbent (lime, sodium bicarbonate); can be dry (DSI), semi-dry, or wet. See DeSOx.

DSI (Dry Sorbent Injection)

Injects a powdered sorbent directly into the flue gas to neutralize acid gas in the gas phase, with the reaction products captured in the downstream baghouse; a low-capital method.

DeNOx / Nitrogen-Oxide Removal

Reduces nitrogen oxides (NOx) in flue gas to nitrogen and water using ammonia/urea. See DeNOx.

SNCR

Selective Non-Catalytic Reduction: injects the reagent (urea/ammonia) into a high-temperature zone (~850-1100°C) without a catalyst; typically 30-60% NOx reduction.

SCR

Selective Catalytic Reduction: reacts the reagent over a catalyst at lower temperature (~250-400°C); can reach 90%+ NOx reduction.

Activated Carbon Adsorption

A polishing stage that captures gas-phase pollutants such as VOC, odor, mercury, and dioxins on a porous carbon surface. See activated carbon filters.

Acid-Gas Removal (SO2, HCl, HF)

Neutralization of acid gases in flue gas with an alkaline sorbent or wet scrubbing. See SO2/HCl acid-gas removal.

Demister (Mist Eliminator)

An element at the wet-scrubber outlet that captures entrained water droplets and prevents liquid carryover to the stack.

Pneumatic Conveying Terms

Pneumatic Conveying

Moves powder/granular material through a closed pipeline with an air stream, with no spillage or dust loss. See our product range.

Dense Phase / Dilute Phase

Dense phase conveys material at low velocity (less wear and breakage; for abrasive/friable material); dilute phase conveys at high velocity (simple and economical; for robust material).

General / Design Terms

Air-to-Cloth Ratio (A/C)

The gas flow through a unit of filter area (m/min). The most critical baghouse design parameter; too high and emissions and pressure drop rise while bag life falls. See baghouse calculator.

Can Velocity

The upward gas velocity in the space between bags. If too high, dislodged dust re-attaches to the bags (re-entrainment) and efficiency drops.

Pressure Drop (ΔP)

The pressure difference between inlet and outlet. It directly drives fan power; a rising ΔP can indicate blinding or faulty cleaning.

PM10 / PM2.5

Particulate matter smaller than 10 and 2.5 microns respectively. PM2.5 is respirable fine dust and the most demanding fraction for emission limits.

VOC (Volatile Organic Compound)

Easily evaporating organic compounds (solvents, paint vapors, etc.). Removed with activated carbon, biofilters, or thermal oxidation.

ATEX

The explosive-atmospheres directive. It requires equipment handling flammable dust or gas to be designed with explosion venting/suppression.

Emission Limit (mg/Nm³)

The allowed pollutant mass per volume of gas at normal conditions. Equipment selection is often triggered by compliance with this limit.

Let's determine the right solution together

To move from a term to a solution, reach MDSJ Process (DUCON brand): contact us for a free technical assessment of your flue gas, or explore our full product range. Related guide: baghouse vs wet scrubber selection guide.