Nitrogen Dioxide: Friend and Foe?

dev on Aug. 16, 2024

Nitrogen Dioxide (NO2) emissions pose a significant challenge for exhaust emission manufacturers due to the health hazards they present, particularly in confined underground mining areas.
NO2 emissions are regulated by agencies like the California Air Resources Board (CARB) and the Environmental Protection Agency (EPA), as well as mining authorities like the US Mine Safety and Health Administration (MHSA)  and Canadian Centre for Mineral and Energy Technology (CANMET).

The Dual Role of NO2 Emissions

Nitrogen dioxide emissions produced by diesel engines are a double-edged sword. While NO2 is necessary for the passive oxidation of soot particles—a critical process for reducing particulate matter; NO2 emissions pose health risks that can be detrimental.

On one hand, diesel exhaust catalysts that use precious metals (PGM) can both generate NO2 and use it to oxidize soot in a particulate filter; the challenge is balancing these reactions to minimize the NO2 health effects without compromising the effectiveness of soot oxidation.

CDTI’s CatTrap® DPF System: A Breakthrough Solution

The solution to effectively reducing NO2 emissions lies in CDTI’s CatTrap® Diesel Particulate Filter (DPF) system. This innovative system employs a base metal catalytic formulation that eliminates the need for PGM. The key advantage of this formulation is its ability to oxidize soot without generating NO2, effectively destroying NO2 instead.

How Does CatTrap® Work?

The CatTrap® catalytic technology is highly selective, utilizing NO2 in conjunction with oxygen in the exhaust stream to efficiently oxidize soot particles. Due to this unique characteristic, there will always be less NO2 exiting the CatTrap® DPF vs. what came in.  During normal duty cycle conditions, PGM coated DPF’s can unintentionally create excess NO2.

As exhaust flows into the open inlet cells, it is forced through micro-porous walls into the outlet cells, filtering out diesel particulates.

The filter substrate is coated with a proprietary catalytic layer that reduces the combustion temperature of soot to within the normal operating range.

The CatTrap® DPF achieves passive regeneration when the engine is in use and under load.  During normal usage, the cleaning interval for the CatTrap® DPF meets or exceeds industry standard.

Designed for Versatility

The CatTrap® system is available in a variety of sizes and orientations, fitting in almost any installation space envelope.  CDTi can also custom manufacturer the CatTrap®, which is ideal for Original Equipment Manufacturers. Each CatTrap® comes with a backpressure monitor kit and can be installed as a single or dual unit, either vertically or horizontally.

Why Silicon Carbide?

The CatTrap® features a Silicon Carbide (SiC) filter substrate. It is well known throughout the emission control industry that Silicon Carbide filters are capable of withstanding high temperature and back pressure events, making it the most durable product available.  Silicon Carbides unique filtering capabilities trap over 99% of engine exhaust soot.

The Advantage of Base Metal Catalysts

The advanced base metal soot ignition catalyst used in the CatTrap® does not produce NO2 emissions during passive regeneration. This feature is crucial for applications in confined spaces with limited ventilation, like underground mining operations.

Meeting Mining Needs with the CatTrap®

The CatTrap® excels in environments where other DPF systems fall short. CDTi has been a pioneer in the development of catalyst technology for mining operations since 1990. The CatTrap® was the first catalyzed diesel particulate filter recognized by MSHA that does not promote NO2 formation.