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A Leader in Silencing for Industry

Catalyst Exhaust Silencers


“THREE -WAY” NSCR  for VOC, CO and NOx Reduction

Engine Operation

Control Technology

Target Pollutants

Rich-burn

NSCR Catalyst (Three-way)

NOx, CO, VOC

Stoichiometric

NSCR Catalyst (Three-way)

NOx, CO, VOC

Lean-burn

Oxidation Catalyst (Two-way)

CO, VOC

Lean-NOx Catalyst

NOx, CO, VOC

SCR Catalyst

NOx

Ceramic Coating

NOx, CO, VOC

A General Description of NSCR

An NSCR system reduces NOx, CO, and hydrocarbon (VOC) emissions from a rich-burn engine when the air-to-fuel ratio is near stoichiometric (14.7 to 1). When a rich-burn engine is tuned strictly for performance, oxygen is in the 1% to 3% range.

 

At this AFR, CO and hydrocarbon emissions are low and NOx is high, because the engine is running hot for maximum efficiency. When using an NSCR system, the engine must be operated richer so that an increase in reducing agents (CO and hydrocarbons) occurs. In addition, the NSCR must be operated at a temperature adequate to accomplish NOx reduction, typically at least 750F. The catalyst is designed to produce the following reactions:

NOx + CO -- N2 + CO2

NOx + CH4 -- N2 +CO2 + H2O

NOx + H2 -- N2 + H2O

If there is too much oxygen in the exhaust, the preferential reaction in the catalytic converter is the oxidation of CO or hydrocarbon rather than the reduction of NOx. Thus, with NSCR, the oxygen concentration should always be less than 1%, and preferably under 0.5%. The air-to-fuel ratio controller uses an oxygen sensor placed in the exhaust stream near the catalyst inlet as a feedback signal to keep the AFR at the optimum set point. The sensor is particularly sensitive to oxygen concentrations below 1%.

 

Some conditions that can reduce catalytic activity over time are thermal degradation, poisoning, or masking. Thermal degradation is caused by sintering of the wash coat, which closes the pores, thereby reducing catalyst surface area. Sintering can occur slowly over time, or quickly if the catalyst is operated at a temperature that is too high. Too much sulfur or phosphate in the engine oil or fuel can cause poisoning of the catalyst. Masking occurs when soot is deposited on the catalyst because the engine is burning oil.

 


 

EPA Information and Links: 

 

Air Toxics


RETRO-FIT OF EXISTING 2 CYCLE ENGINES:

• COOPER-BESSEMER

• INGERSOLL RAND

• WORTHINGTON

• DRESSER

• CLARK

• FAIRBANKS MORSE

• EMD


NEW & EXISTING 4 CYCLE ENGINES:

• CATERPILLAR

• WARTSILA

• WAUKESHA

• MAN DIESEL


TYPICAL PERFORMANCE:

NOISE REDUCTION - D.I.L. (Dynamic Insertion Loss)

Model

Grade

Typical

Overall

D.I.L.

121 Industrial 20 dB
131

Industrial

Residential

20-25 dB
141 Hospital 30-35 dB
144 Critical 45 dB
154 Super Critical 50+ dB

 


CATALYST FEATURES:

• Optimal conversion efficiencies with reduced catalyst volume.

• Heavy-duty stainless steel modules.

• Cell densities up to 700 cpsi.

• Lowest pressure drop for the most surface area.

• Individually mounted module design.

• Broad operating temperature range (350F to 1200 F).

 


Typical Catalyst Engine Silencers:

 

           


VANEC ADVANTAGES:

• Custom designed for ease of field maintenance with 

low chamber element/module access.

•Proven ability to meet noise and emission specifications 

in a combined unit.

•Designed to mount on existing foundation and exhaust

center lines.

 


VANEC incorporates catalyst modules in various shapes and sizes

engineered by ™PCA, Inc. and manufactured by ™EmeraChem LLC.

 

 

 

Pollution Control Associates: (For Lean Burn Engines.)

        ADCAT ™ CO Catalyst for COm VOCs, Formaldehyde Oxidation

 

 


 

 

Made In

USA


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Rev:12/12/2013