New catalyst/silencer from Universal - emissions

Diesel Progress North American Edition, Feb, 2004 by Mark McNeely

Universal Silencer Inc. (USI), a global noise control and air filtration designer and manufacturer based in Stoughton, Wis., has two new emissions solutions available for stationary diesel and gas engine applications: a combination silencer/ catalyst and an emissions catalyst unit.

The combination silencer/catalyst is a variation of the USI EN series heavy-duty engine exhaust silencer, extended slightly to allow room for catalyst insertion. It utilizes one of two catalyst capturing techniques within the silencer shell. The first employs a gasket-wrapped catalyst module, which fits tightly between internal guide rails. The second uses a 'torturous path' configuration, which uses serpentine interlocks around the catalyst to prevent gas bypass. Both designs seal the silencer and ensure that exhaust gas passes through the catalyst, the company said. The combination silencer/catalyst solutions are available in four performance grades, with overall attenuation to 40 dB(A), according to the company.

"Although diesel engines are embraced for low greenhouse gas emissions, other byproducts such as nitrogen oxides (N[O.sub.x]), sulfur oxides (S[O.sub.x]) and diesel particulate matter (PM), have taken center stage as the most feared toxic contaminants in diesel exhaust," said Ken Murray, marketing programs manager for the company. "Universal Silencer's push with the new line of silencer/catalyst is to provide an engineered package that will address both the noise control and emissions concerns. By knowing the emissions device, USI feels it can better design an optimal noise control solution for each application."

USI's base catalyst housing packages are large end-in, end-out configured units with a flanged inlet and outlet connection. Conical sections or standard dished silencer heads are used, depending on the pressure drop requirements of the unit. The cylindrical housing body can incorporate either of the catalyst capturing designs as the combination silencer/catalyst units. This complete catalyst package includes multiple pressure, temperature and other measuring ports, and is available in various stainless steels or standard carbon steel.

"USI is the acoustic, back pressure, engineering and packaging expert in this equation," Murray said. "USI manufactures the silencers and housings that hold the catalyst. Johnson Matthey, a specialty chemicals company focused on its core skills in catalysts and precious metals, is USI's catalytic technology partner in this market. JM supplies the catalysts and engineering resources for the product line."

Depending on catalyst formulation and required pressure drop levels, USI's silencer/catalyst can reduce PM emissions by as much as 85% and CO (carbon monoxide), HC (hydrocarbons), VOCs (volatile organic compounds), HAPS (hazardous air pollutants) by as much as 90%.

A history of close collaboration with sister company Fleetguard Emissions Solutions has also enabled USI to incorporate several customized design characteristics into its silencers and catalyst packages for optimum catalytic and acoustic performance. The result is a specialized emission and noise control solution that integrates many decades of acoustic and emissions expertise, Murray noted.

USI is also working with EAS, a Crystal Lake, Ill.-based emissions sales group that has supplied these solutions to the gas transmission market.