|  Introduction
Plants that use
a lot of pneumatic tools or automated product handling, likely use a substantial
amount of compressed air. There are natural gas engine drive air compressors available
for this market.
Application
If the plant has
at least 100 hp of air compression capacity, running at least 7,000 hours per
year and 70% capacity, then they are a candidate for natural gas engine drive.
Heat recovery is an option, but the need for heat must be balanced with the added
cost of the heat recovery equipment. With these parameters, payback can be in
the 2-3 year range; larger sizes or increased run hours will payback quicker.
If demand charges are high, run hours can be less important.
Electric compressor
drives can be a significant part of the electric demand and are very inefficient
at part loads. Studies have shown that air compressors typically run at 60% load
factor. Conventional electric motors require 90% of the full load electricity
at part load. Gas engines running at reduced RPMs require only 62% of inlet gas.
(With a rotary screw drive compressor and load control.)
Heat recovery
of 30% of inlet gas BTU rating can be recovered as hot water. The heat must be
usable at all times that the compressor is running, or a heat dump system must
also be added.
How it
Works
Most manufacturers
of gas engine-driven air compressor packages, are primarily manufacturers of electric
motor-driven packages. Gas engine-driven lines were developed to meet the demands
of a small number of their customers and sometimes with funding from the gas industry.
The engine units have remained a very small niche market.
Simply stated,
take an electric package, remove the motor and add an engine, and you have an
engine-driven package. Of course it is not that simple to get the controls, cooling
systems, and coupling devices to work properly, but essentially, that is what
the engine packages are.
Manufacturers
There are many
custom packagers who will build custom systems, mostly in large horse power sizes
(500 hp and up). There are a few "packaged" systems that are built to
a standard specification and are therefore considered 'off-the-shelf' technology.
It is CRITICAL
that engine-driven air compressors be purchased from someone with LOCAL support
where the unit will be installed.
More Information
For more information
about engine-driven air compression, please visit our Air Compressor Consortium
web site at www.aircompressor.org
Source: Energy
TechPro
 
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