How Marine Vessels Use Compressed Air and Nitrogen

Compressors on land are common – but compressors on sea? That’s right! The use of air compressors aboard marine vessels is also commonplace, with boats, tankers, and LNG vessels alike employing this equipment to power their onboard applications. However, the difference in environments necessitates that the marine air compressors function in slightly different ways than their landlocked counterparts. Read on to discover a few of most common marine applications made possible by air compressors.

Starting Air. Compressed air is used on ocean-going vessels as a powerful and storable energy source for starting larger diesel engines. Although at the point of use air is used at a lower pressure of <150 psi, it is typically stored at higher pressures to better utilize space, while still allowing enough volume for multiple starting attempts. Ship locomotion and the control of the main and auxiliary engines are also pertinent applications powered by compressors.

Control, Instrument and Working Air. There are many onboard systems and processes that require compressed air. Engine emissions monitoring systems, throttle controls, control valves and tool air (for chisels, drills, and grinders) are just a few examples.

Water Supply. Storing clean water onboard ships is crucial to maintaining life at sea. Compressors are essential in pressurizing the hydrophores that maintain this fresh water supply, as well as for distributing the water from the hydrophores to users across the ship.

Sewage Breakdown. Onboard sewage systems are powered by compressed air, with this equipment playing a large role in the onboard sewage plant and in conducting aerobic sewage breakdown.

Emergency Services. Air compressors are essential to powering safety features onboard ships, including ship whistles and foghorns! In cases of true emergencies, compressors also power the fire pumps that access the seawater, as well as the motors that move the lifeboats up and down the ships, if those become necessary.

Hull Lubrication Air. As a ship moves through water, it encounters resistance. With a specially engineered vessel hull, low-pressure air (generated by low-pressure blowers) can be blown through small holes to create a layer of air between the hull and water. This layer will reduce the resistance of the vessel with a potential fuel consumption efficiency of more than 25 percent and significantly reduced CO2 emissions.

Tank Blanketing. Vessels using LNG (liquefied natural gas) as a fuel source, or who are transporting LNG, are required to blanket their fuel tanks with nitrogen to prevent the possibility of an explosion. Instead of bringing nitrogen tanks on board, it makes more sense to generate nitrogen on-site. To do this, vessels must first have access to an air compressor.

Cleaning LNG Pipework. Nitrogen is also often used (along with air compressors) during the process of cleaning the LNG pipework and storage tank. Because it is a dry, oxygen-free inert gas, using nitrogen as an agent for flushing and/or purging a ship’s LNG tank engines and fuel lines can greatly reduce the potential for combustion and explosions during the process.

When your marine or offshore application requires compact, energy-efficient compressed air and nitrogen solutions that are class-approved and built to withstand the harshest of conditions, look to our complete, offshore-specific product portfolio! You can also reach out to us at www.atlascopco.com/air-usa, where our product experts are available to assist you in selecting which of our marine compressor options are the best fit for your needs.