Reduced emissions and increased fuel efficiency go hand-in-hand
Crowley Maritime Corporation has been known for its cutting-edge technology in the maritime trade, dedication to safety and the environment, and desire to provide ever-increasing value and service to its customers. Now, in an age of increased environmental awareness, new commitments to reducing emissions and pollution in the air have Crowley investing in engine modifications on its 10 tugboats dedicated to the Puerto Rico/Caribbean liner service and on its four tugs chartered to Trailer Bridge for their Puerto Rico barge service.
Crowley makes four to five trips per week between the United States and Puerto Rico, which provide ample opportunity to test and perfect engine modifications that have led to lower exhaust emissions and increased performance. Exhaust emissions take on a number of forms including visible smoke, particulate matter and nitrogen oxides (NOx). Crowley is working to reducing all three while achieving heightened performance with decreased fuel consumption.
“We are always looking for more efficient and cleaner ways to run our engines,” said Rob Grune, senior vice president and general manager, Puerto Rico/Caribbean services. “We have an extremely talented engineering department that has a genuine interest in maintaining our high performance standards, while optimizing equipment for environmental preservation.”
Engineering Upgrades Key
Through a series of engineering upgrades, Crowley has partnered with General Electric, Rolls Royce, Marine Systems and Interstate Diesel to reduce exhaust, cut engine lubricating oil consumption and save fuel.
In addition to using low sulfur diesel fuel, Crowley has installed ECOTIP fuel injectors in all of the tugs in its Puerto Rico service, which has helped reduce fuel consumption and the amount of particulate matter by 44 percent. Additionally, the clarity, or opacity of stack emissions has improved by 75%.
Also contributing to improved fuel efficiency, cleaner burning engines and reduced stack emissions are new fiberglass air filters with a pleated paper design. These filters provide less restriction of airflow into the engine and better air cleaning prior to entering the tug’s turbocharger thereby maintaining efficiency.
Additionally, the tugs have special four-pass aftercoolers instead of traditional two-pass coolers, ensuring that the air temperature is lowered and density is increased as the air enters the engine. The cooler, denser air flowing into the engine allows for more complete combustion and increased fuel efficiency while maximizing the engine’s power. Vent modifications and stronger vent fans in the engine room keep the air pressure up and the temperature down. The further cooling of this ambient air temperature again increases efficiency and reduces fuel consumption and stack emissions.
New extended life, emissions-reducing power packs have been installed for testing purposes in some of the tugs in the fleet. Also proving their worth are custom designed piston rings, which require less oil for operation.
The final piece of Crowley’s move towards more efficient, environmentally friendly tugs is the development and installation of new generation Rolls Royce propellers. The new generation work wheels provide state of the art hydrodynamic design, which significantly improves cavitation, performance and overall efficiency. The combination of these different modifications have all worked together to decrease oil and fuel consumption while not compromising efficiency and speed, thus allowing Crowley to maintain the service schedule and sailing frequency to which the people of Puerto Rico have become accustomed.