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MAN Diesel & Turbo delivers IMO-certified two-stroke engine

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Oilfield Technology,

Hyundai’s Ship Building Division (HHI-SBD) has announced the finalisation of a contract for 2 × Suezmax tankers for Turkish shipowner, Ditas Shipping.

The 158 000m3 crude-oil tankers will each be powered by individual MAN B&W 6G70ME-C9.5 two-stroke main-engines that feature integrated Exhaust Gas Recirculation (EGR) systems. While there are already IMO Tier III-compliant vessels with EGR systems in service, the Suezmax newbuildings will be the first vessels with keel-laying after 1 January 2016 to be officially certified as complying with Tier III emission restrictions within existing North American NOx Emission Control Areas (NECAs) and the US Caribbean Sea NECA.

EGR is a NOx emissions-control technology that works by recirculating a portion of an engine's exhaust gas back to the engine cylinders.

A part of the exhaust gas is drawn through a scrubber, cooler, and water mist catcher by suction created from a specially designed blower. The blower raises the pressure of the exhaust gas, which is then mixed with the charge air via a unique charge air pipe, before entering the main-engine coolers.

Within the scrubber, the exhaust gas is washed with water. Sodium hydroxide dosing is required to neutralise the consequent acidic scrubber water. In addition, the scrubber washes out particulate matter (PM) that becomes suspended in the scrubber water.

A fully automated control system provides for easy operation for the ship’s crew and correct and swift reactions to engine load variations.

MAN Diesel & Turbo have evaluated the possibility of using even larger propellers and thereby engines with even lower speeds for the propulsion of tankers and bulk carriers.

Such vessels may be more compatible with propellers with larger diameters than designs so far used, and therefore able to facilitate higher efficiencies following adaptation of the aft-hull design to accommodate a larger propeller. It is estimated that such updated aft-ship designs with the G-series of engines offer potential fuel-consumption savings of some 4-7%, with a similar reduction in CO2 emissions.

Simultaneously, the engine itself can achieve a high thermal efficiency using the latest engine process parameters and design features.

Edited from press release by

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