LNG Carrier Propulsion by ME-GI Engines and/or Reliquefaction

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ME-GI The Dual Fuel Engine In order to make it possible to use the Boil Off Gas from an LNG Carrier as fuel in low speed diesels as well, MAN B&W has readdressed this technology based on our ME engine concept. The benefits of the greater control given by the ME engine range further enhance the operational reasons for introducing this option. Some years ago, MAN B&W developed the MC range of engines for dual fuel. These were designated MC-GI (Gas Injection). The combustion cycle was initiated by the injection of pilot fuel oil, followed by the main gas injection. The technology was widely published as, for Fig. 5: ME-GI engine and gas handling units 6 instance, in Ref. [2]. The fuel injection timing on these dual fuel engines was mechanically controlled, but in the electronically controlled version, like all ME engines, it can be user-defined and is subject to greater control and flexibility, thereby allowing the dual fuel concept to be further optimised. The efficiency of the ME-GI duel fuel engines is the same as an ordinary ME engine, due the diesel cycle. The system efficiency will be higher than that of other gas consuming propulsion system, incl. dual fuel diesel electric even considering the compressor power. Internal and external systems for dual fuel operation Engine room Outside Gas system on the cylinder Sealing oil system Exhaust receiver Cylinder cover Valve block Full redundancy as required by International Association of Classification Societies’ (IACS) can be met with one compressor, one reliquefaction unit or one oxidizer as also discussed later. The system configuration is shown in Fig. 5. Double wall pipe Gas pipe Air flow direction Gas flow direction Fuel oil pressure booster Inert gas line Pipe Ventilation system Gas supply system ELFI valve ELGI valve Servo oil STACK Reliquefaction unit Gas oxidizer Compressor unit B.0. gas LNG B.0. gas B.0. gas
Elements of the ME Engine The mechanical difference between an MC-C engine and its electronically controlled counterpart, the ME-C engine, constitutes a number of mechanical parts that are made redundant and replaced by hydraulic and mechatronic parts with enhanced functions. The following parts are omitted: • Chain drive Chain wheel frame • Chain box on frame box Camshaft with cams • Roller guides for fuel pumps and exhaust valves • Fuel injection pumps • Exhaust valve actuators • Starting air distributor • Governor • Regulating shaft • Mechanical cylinder lubricator • Local control stand The above-mentioned parts are replaced by: • Hydraulic Power Supply (HPS) • Hydraulic Cylinder Units (HCU) • Engine Control System (ECS), • Crankshaft position sensing system • Electronically controlled Alpha Lubricator • Local Operating Panel (LOP) Fig. 6 shows how the necessary power for fuel injection and exhaust valve operation – previously provided via the chain drive – is now provided from a Hydraulic Power Supply (HPS) unit located at the front of the engine at bedplate level. The main components of the MC ME Hydraulic Power Supply unit are the following: • Self cleaning filter with 10-micron filter mesh • Redundancy filter with 25-micron filter mesh Before engine start, the hydraulic oil pres- Hydraulic Power Supply Generates the power necessary for fuel oil injection and exhaust valve opening Fig. 6: Hydraulic Power Supply (HPS) • Start-up pumps: Electrically driven pumps with supply pressure of 175 bar • Engine driven axial piston pumps supplying high pressure oil to the Hydraulic Cylinder Unit with oil pressures up to 250 bar 7
Page 1: LNG Carrier Propulsion by ME-GI Eng
Page 4 and 5: Diesel Engine Technology MAN B&W of
Page 8 and 9: Fig.7: ME engines, hydraulic oil lo
Page 10 and 11: Another system that benefits from m
Page 12 and 13: ecause the p max can be kept high a
Page 14 and 15: Reliquefaction Technology While rel
Page 16 and 17: Redundancy • Redundancy is requir
Page 18 and 19: LNG Carriers LNG carriers, like oil
Page 20 and 21: Economical Evaluation The operating
Page 22 and 23: Appendix Power Consumption Options
Page 24 and 25: Basic Data for Economical Compariso
Page 26: Basic Data for Machinery Boiler and

LNG Carrier Propulsion by ME-GI Engines and/or Reliquefaction

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