Desuperheaters0 pages

Bulletin 6D

Steam Desuperheaters
INTRODUCTION
In 1923 Schutte & Koerting introduced its first
mechanical spray desuperheater, and three years later
the company introduced a surface absorption unit. In
1939 the venturi desuperheater was developed and
successfully marketed to satisfy a wide range of
applications. An ejector, atomizing type unit, introduced
in the mid 1950’s, lead to numerous variations and larger
capacities. This was followed by a mechanical dumptype unit for critical power plant needs. The newest unit
is the annular venturi desuperheater which compares
favorably with competitive spray nozzle designs.
APPLICATION
Although requirements for desuperheaters cover a wide
range of applications, the great majority fall into the
following standard installations:

• Power plant requirements for desuperheated steam
supplying units having limited operating temperatures
such as auxiliaries, heating systems, heat exchangers
and, more recently, dump stations.
• To improve heat transfer of surface-type heat
exchangers.
• Reduction and control of superheated steam, where
excess temperatures will harm the product.
• Use on boilers, either between superheater stages or
at boiler exit, to control superheat temperatures at
partial loads.
• Use as bypass of bleeder or back pressure turbines to
maintain balance between process steam and power
requirements.

then mixed with a percentage of steam through the throat
region and introduced into the steam line as a finely
atomized mist. Water entrainment, shearing and
mixture, all within S&K internal construction, produces
extremely small water particles and alleviates
requirements of thermal liners and impingement shields.
For Type 6905, where water is injected at high pressure
and internal construction consists of a water nozzle, S&K
supplies or recommends thermal liners.
MATERIALS OF CONSTRUCTION
S&K desuperheaters are manufactured from a variety of
metals. Standard construction is carbon steel below
800°F, chrome molybdenum steel above 800°F (both
with stainless steel Type 304 internals); however, S&K
can manufacture in any metal or alloy requested.
QUALITY CONTROL

• Miscellaneous applications where balancing or makeup steam is required in reduced pressure systems in
refineries and process plants.

S&K products are subjected to extensive tests required
by stringent quality control policies. Equipment can be
manufactured to various ASME or ANSI codes and/or
provided with special non-destructive testing. Details on
facilities and techniques will be supplied upon request.

OPERATION

PERFORMANCE

S&K desuperheaters reduce the temperature of
superheated steam to produce lower temperatures
(normally 10ºF above saturation, although Type 6910 is
capable of producing saturated steam). The majority of
S&K units (except Types 6905 and 6910) require water
at line pressure. Water is syphoned into the water
box/combining tube assembly, where it is heated, and

Data for sizing, determining pressure drop, straight run
requirements, bulb placements, etc. can be found in the
Engineering Data Supplement to Bulletin 6D.

Schutte & Koerting • 2510 Metropolitan Drive • Trevose, PA 19053 • USA • tel: (215) 639-0900 • fax: (215) 639-1597 • www.s-k.com • sales@s-k.com

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