21 October 2003 – Caterpillar Inc. has introduced a 1200 rpm version of its Cat G3520C advanced natural-gas-fuelled generator sets, offering the highest fuel efficiency in its class, low maintenance and reduced operating costs in extended-duty distributed generation and cogeneration applications.
The 1200 rpm/60 Hz package delivers 1.6 MWe from an electronically controlled, 20-cylinder advanced lean-burn gas engine, coupled with a six-pole synchronous generator. Mechanical efficiency is rated at 43.5 percent, with fuel consumption at 6,069 Btu/bhp-hr, and NOx emissions at 1.0 g/bhp-hr. For applications with even lower emissions needs, the G3520C gen set is also available in a 0.5 g/bhp-hr NOx version.
“This unit fills the need for a low-first-cost, low-emission generator set that also provides competitive electricity cost in longer-running applications,” says Michael A. Devine, gas product marketing manager with the Electric Power Group of Caterpillar Inc.
“The 1,200 rpm G3520C delivers 4 to 5 percent greater fuel efficiency than the previously introduced 2.1 MWe 1,800 rpm version. As such, it is an economically attractive choice for cogeneration and distributed generation service ranging from 1,000 to 2,000 annual run hours all the way up to continuous duty. We accomplished the transformation to 1,200 rpm without the addition of a gearbox, thus reducing maintenance and service requirements, Devine says.”
Like the Caterpillar 1,800 rpm G3520C generator set introduced in December 2002, the 1,200-rpm version is designed to operate reliably and economically with minimal hands-on operator attention. It uses the same open combustion chamber design and low-pressure fuel system (1.5 to 5 psi/10 to 35 kPa), making it adaptable to a wide range of applications. The G3520C also features:
* SCADA-compatible ADEM IIIô digital microprocessor control technology for automatic regulation of engine governing, air/fuel ratio and ignition systems control, resulting in optimum fuel economy and stringent NOx emissions control.
* Electronically controlled transient response systems to minimize frequency and voltage fluctuations during block loading and unloading (The Cat G3520C meets ISO 8528-5 standards for recovery time, voltage dip and frequency deviation for block loads up to 25 percent.).
* Patent-pending air/fuel ratio control based on charge air density to maintain NOx within tight tolerances under all ambient and load conditions.
* Cylinder-by-cylinder detonation sensing.
* Pre-chamber-type spark plugs for extended service life without adjustment.