Turbomachinery for Nitric Acid Plants - MAN Diesel & Turbo

Centrifugal compressor for air
For smaller plants using the mediumpressure
process with pressures of
about 6 bar, as weil as for highpressure
plants operating in the range between 7
and 15 bar, economically the best solution
today is to use an integrally geared
compressor. Theses multi-shaft compressors
have the advantage over
single-shaft machines, that they allow
direct drive and the integration of a tail
gas expander.
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These compressors of the type “RG”
are built by MAN Turbo with a maximum
number of six stages.
By varying the number of intercoolers,
the gas can be delivered at the temperature
required by a particular process.
For the medium-pressure range an uncooled
version is also available.
The advantage of this type of compressor
is that it can be driven either by an
electric motor or by a turbine or by both
at the same time.
For motor driven units, the bull gear is
driven directly. Whereas for the turbinedrive
version MAN Turbo has developed
a design with an additional pinion shaft,
whose transmission ratio is chosen to
allow the compressor to be driven either
by the tail gas expander or the steam
turbine at its optimum speed. The MAN
Turbo integrally geared compressor
offers the following advantages:
high efficiency due to optimum impeller
design, optimum speed selection,
and interstage cooling
low operating costs due to high efficiency
and minimum maintenance
oil-free compression
excellent part-load performance
high availability
simple operation due to fully automatic
control and monitoring
rugged, compact design.