AET set to achieve fuel savings with tankers that use VOCs as bunkers

Wartsila wins contract to install its VOC recovery technology aboard two new shuttle tankers.

Tanker schematic: The recovery of VOC is accomplished by introducing tank vent gas into the VOC recovery system, and then using a condensation process to separate the heavier hydrocarbon fractions of the gas. The lighter hydrocarbon fractions are non-condensable and are fed to a power generating module, meaning that the VOC recovery is 100% and VOC emissions are entirely eliminated.

The separated heavier fractions are liquefied from the VOC unit and stored in a pressurized storage tank. LVOC is a light hydrocarbon fuel that can be utilized as a clean fuel in power generating modules and inert gas generator units. The Wartsila VOC recovery system has been utilized aboard several shuttle tankers and floating storage units (FSU) in the North Sea. Image credit: Wartsila

Updated on 26 Mar 2018 09:46 GMT

Wartsila has announced that it will supply its volatile organic compounds (VOCs) recovery technology, LNG fuel gas handling systems and the auxiliary engines for two new shuttle tankers being built for Singapore based AET Tankers at the Samsung Heavy Industries shipyard in South Korea. The order, worth in total more than EUR 30 million, was booked in January 2018.

The ships will operate on LNG as the primary fuel, but VOC - the gas evaporating from the oil cargo tanks - will also be utilised as fuel by mixing it with the LNG, thereby reducing the vessels' bunkering needs.

This is made possible by Wartsila's VOC recovery system, which by combining the VOC with the LNG, is said to provide the potential for savings of more than 3,000 tonnes of fuel each year per vessel.

Wartsila says it expects its technology for creating a fuel mix of LNG and recovered VOC, both for the two-stroke main engine as well as the four-stroke auxiliary engines, to ignite the interest of tanker fleet owners around the world.

Timo Koponen, Vice President, Vice President, Processing Solutions, Wartsila Marine Solutions, remarked: "Wartsila is once again ahead of the curve with its VOC recovery technology, which was a key consideration in the award of this contract. The fuel savings efficiency of the system enables a fast payback time, while the reduction in emissions of CO2 equivalents is as much as 40 percent when compared to conventional solutions.

Wartsila's scope of supply for each of these ships includes the VOC recovery plant, the liquefied VOC fuel tank, the fuel mixing unit, the LNG fuel tank and fuel supply system, the gas valve unit (GVU) and two Wartsila 34DF dual-fuel auxiliary engines. The equipment is scheduled for delivery to the yard commencing in the autumn of this year.

The 277-metre-long, 125,000-deadweight-tonne (dwt) tankers are due to operate mainly for Statoil in the North Sea.