MAN Diesel Australia has booked its first order for the new engine
A computer rendering of the Owen Springs Power Station turnkey project recently awarded to MAN Diesel Australia by Darwinbased Power & Water Corp. The power station will be based on two 10.9 MWe generator sets powered by MAN Diesel 12V 51/60DF dual-fuel engines.
The recently introduced 51/60DF dual-fuel engine from MAN Diesel has now passed its second major milestone in electrical power generation applications. Following closely on the handover of a heavy fuel engine retrofitted to full 51/60DF specification at an existing cogeneration installation in Portugal, MAN Diesel Australia has now booked the first order for the new 51/60DF engine in a power plant application.
The turnkey contract has a value of approximately US$40 million and covers the design and construction of a new 22 MW power station at Owen Springs, 25 km south of Alice Springs, for Power and Water Corp. (PWC), a major Australian public utility serving more than 80 000 customers in the Northern Territory. PWC has 360 MW of existing power generation capacity.
The new Owen Springs Power Station will be based on two 10.9 MWe generator sets, each powered by a 12-cylinder, Vee-configuration 12V 51/60DF engine. The generator sets will supply base load power to the local grid in their gaseous fuel mode, which in this case will include burning natural gas ignited by a distillatefueled micropilot. Completion of the first stage of the project is scheduled for April 2009, with final completion in 2010.
“With its fuel flexibility and low emissions, the 51/60DF targets power generation applications both on land and at sea where operation on a backup fuel is either essential or desirable,” said Stephan Mey, head of MAN Diesel’s Power Plant business unit. “This is achieved by the capability to operate the engine on either gaseous fuel or liquid fuel at full rated output and to seamlessly switch between gaseous and liquid modes at any output.”
For stationary power generation applications, the 51/60DF is available in a ninecylinder inline configuration and in Vee configurations of 12, 14 and 18 cylinders. The engines have mechanical ratings of 1000 kW per cylinder for 60 Hz power generation at 514 r/min and 975 kW for 50 Hz applications at 500 r/min. These give an overall gen-set rating range of 8560 to 17 550 kWe.
Looking at the overall design of the 51/60DF, it is based on MAN Diesel’s 48/60 engine platform, the mainstay of the company’s power generation business. Given this common heritage, MAN Diesel expects that electrical power utilities and IPPs operating 48/60A and 48/60B generator sets on distillate or heavy fuels will be especially interested in retrofitting dualfuel technology.
“As with the market for new 51/60DF engines, the retrofit market is driven by the increasing availability of natural gas all over the world and the spread of clean-air legislation to new regions,” noted Mey. “Emissions of NOx and particulates are always a special focus of clean-air legislation, and substituting liquid fuels with natural gas — either by installing new engines or retrofitting existing ones — is an obvious and well-proven way of reducing emissions of both. In fact, over the past few years we have concluded con-tracts for diesel engines specifying conversion to dual-fuel operation, as and when gaseous fuel becomes available.”
The four-stroke engine is turbocharged with a constant pressure. The bore is 510 mm and the stroke is 600 mm, providing for a swept volume of 122.6 L. Fresh water is used for the cooling of cylinders, charge air and the fuel injectors. The starting is done by compressed air.
At 500 mg/mn3 at 5% O2 on gaseous fuel, the 51/60DF readily achieves emissions of oxides of nitrogen (NOx) in compliance with both Germany’s TA Luft clean-air regulations and the World Bank Pollution Prevention and Abatement Handbook.
In the gaseous fuel mode the air-gas mixture is ignited by injection of distillate diesel fuel, the amount representing 1% of the quantity of liquid fuel needed to achieve full rated output of the 51/60DF. It is injected via a common rail system, which allows flexible setting of injection timing, duration and pressure for each cylinder. This flexibility allows the engine to achieve low emissions and to respond rapidly to combustion knock signals on a cylinder-by-cylinder basis.
In the backup liquid fuel mode, the 51/60DF engine operates as a normal diesel engine, injecting distillate or heavy fuel oil through a separate, normally dimensioned injector in a camshaft-actuated, pump-line-nozzle system.