No silver bullet for emissions: fleet, equipment operators use variety of approaches to reduce diesel emissions

Diesel Progress North American Edition, Feb, 2004 by Edward P. Richards

At the Port of Los Angeles, the busiest seaport in the U.S., numerous programs are underway to improve air quality. Together, these initiatives resulted in a decrease of nearly 1000 tons of N[O.sub.x] and 10 tons of PM in just one year.

Among the targets of the cleanup effort are the 1000 or so diesel-powered yard tractors, forklift trucks, top-pick and side-pick loaders, gantry cranes and other portside vehicles that load and unload more than 120 million metric revenue tons of cargo annually. All are typically sources of heavy engine emissions.

In order to avoid interruption to critical portside operations, however, the Port Authority needed to minimize inconvenience to the tenants that operate within the complex and actually own the vehicles. So two Lubrizol engineers worked for several weeks, surveying vehicles during what little downtime there was and collecting data and measurements from every vehicle.

Based on the results of that survey, Lubrizol teams designed and custom built aftertreatment products specific to the requirements of the dockside fleet, trained port employees on installation and provided emissions documentation for submission to the South Coast Air Quality Management District.

In addition to receiving Lubrizol AZ Direct-Fit Purimufflers, many of the portside vehicles have been converted to use either PuriNOx fuel technology or ultra-low sulfur diesel. Port officials estimate that the installation of a diesel oxidation catalyst on one piece of terminal equipment is equivalent to removing more than 100 cars from the roadway annually. And the effects are noticeable, as dockworkers have seen a significant reduction in smoke emissions from the army of vehicles scurrying around the port.

Reducing emissions is an even trickier challenge in the world of under ground mining, where fresh air is at a premium and miners and diesel-powered machinery work in a confined environment. Stringent regulations by the U.S. Dept. of Labor's Mine Safety and Health Administration (MSHA) have sharpened mine operators' focus on controlling miners' exposure to diesel particulate matter.

As with school buses and portside vehicles, reducing diesel emissions from mining loaders and other underground equipment begins with a fleet survey. Through a relationship with Mine Ventilation Services (Fresno, Calif.), Lubrizol also offers a baseline air quality survey, identifying areas within a mine where emissions are particularly severe.

Equipment-related solutions, custom-tailored to each mine and areas with the mine, typically include combinations of PuriNOx fuel, oxidation catalysts and both active and passive particulate filters. This portfolio includes the ECS Cattrap, a passively regenerating, catalyzed particulate filter specially designed for the underground mining industry. The ECS Cattrap can remove more than 85% of particulate matter.

MSHA now requires that underground mines use particulate filters that do not cause an increase in nitrogen dioxide (N[O.sub.2]) concentrations in the raw exhaust. Recent MSHA tests of commercially available filters found that the ECS Cattrap does not promote the formation of N[O.sub.2].