With the U.S. Environmental Protection Agency’s strictest Tier 4 pollution rules now in effect for marine diesel engines, new vessel builders are looking for the best affordable emission controls.
And fleet operators are looking for ways to retrofit existing diesels that will be around for a long, long time. It won’t be so simple as reducing automobile emissions, Peter Reba of Hug Engineering told operators attending the WorkBoat Maintenance & Repair Conference and Expo in New Orleans, Tuesday.
“We all understand diesel engines don’t die in five years. You can’t do what you did 35 years ago with catalytic converters, which was wait for the [automobile] engines to die,” Reba said at a workshop on the impact of Tier 4 regulations.
Reducing emissions from marine engines is one of the last campaigns in the federal government’s long drive to control internal combustion engine emissions.
The regulators went first after trucks, off-road and construction vehicles and rail transport earlier, Reba said: “The government didn’t chase them all at once, there’s no way they could.”
The reckoning for the marine industries arrived with adoption of a final rule effective in 2014. Despite those efforts so far, emissions remain a public health problem, especially in urban areas where diesel-emitted nitrogen oxides generate ground-level ozone that trigger asthma in people, Reba said.
But existing technology is improving to the point where 85% of nitrogen oxides and particulate soot can be removed, converted by catalytic filters to carbon, nitrogen and water vapor.
Based in Liberty Hill, Texas, Hug (pronounced “hoog”) builds its Hug Filtersystems for both transportation and stationary systems, and is working on government verifications for its Nauticlean marine emissions control systems. Hug is seeking California state verification — the nation’s highest emission standard — for the 85% removal of particulates and nitrogen oxides.
Hug’s system is based around a silicate coating technology on catalytic filters, only a few atomic layers thick, with reduced back pressure on engines and operating temperatures that run 20° to 35° centigrade cooler than similar catalytic systems, Reba said.
A step up is the addition of an active system that raises temperatures in the catalytic “cassettes” to catalyze more material, a regeneration that can be based on time intervals or sensing back pressure on the engine.
The system keeps ships cleaner too, ad can be scaled to any power plant size, Reba said: “You tell me what you want, we’ll size it up for you.”
Even older two-cycle systems like Detroit Diesel can achieve some emissions reductions with the improved technology. It’s an option for operators who want to make initial improvements, and “it is possible to add on … if that is the position you are in,” he said.
