Chemical Technology

25 / 40

23
Chemical Technology • November 2015
FOCUS ON CONTROL & AUTOMATION
According to a recent
report, the OPTIMASS
7000 from KROHNE
is the only sensor for
mass flow with a sin-
gle straight measuring
tube that is available
in titanium, stainless
steel, Hastelloy® or
tantalum.
Steel corrosion can pose a problem during oil production and in
the downstream processing using acidic catalysts, however, this iso
problem for the OPTIMASS 7300 A which boasts a straight measuring
tube made of highly corrosion resistant tantalum alloy. Even difficult
media such as hydrochloric acid, sulfuric acid, nitric acid and other
acids for reaction processes do not attack the measuring tube.
The device is also interesting in terms of the price as a much
smaller amount of tantalum is required for the straight measuring
tube than for devices featuring twin bent tubes. OPTIMASS 7000 fea-
tures the patented Adaptive Sensor Technology (AST), permanently
providing precise and stable measuring results, even under difficult
process conditions and non-optimum installation. Regardless of
whether you are filling phials or tankers, whether the mixtures are
highly viscous or inhomogeneous, or whether it is installed between
flexible hoses or fixed pipelines, results will be successful.
The past decade has seen Coriolis flowmeter technology become
the accepted standard in many chemical industries. However, one
area where the technology was challenged was the measurement of
highly aggressive and corrosive fluids. Generally, the wall thickness
of Coriolis measuring tubes are significantly less than the associated
process piping, which will tolerate a higher rate of corrosion before
failing. This is an area where wetted material selection for a Coriolis
meter is critical.
Tantalum has been used by some Coriolis manufacturers in
the past, but the twin bent tube designs made these expensive. It
was not until the advent of the single straight tube design that the
material became more suitable, since the design now only needed
the measuring tube and the raised face of the process flange to
be made from tantalum. This brought major cost advantages over
the equivalent bent tube designs, but was not easy to achieve as
tantalum does not have the same tensile strength as the titanium
traditionally employed.
KROHNE, a world leader in straight tube technology, has applied
its years of experience and been granted several patents, for per-
fecting the technology of containing the stress created in a straight
tube due to thermal expansion. The company is now in a position to
use this innovative technology for highly aggressive and corrosive
chemicals.
The tantalum used by KROHNE is an alloy called Tantalum Ta10W,
made up of 10 % tungsten and 90 % tantalum. With the addition of
tantalum, KROHNE can now offer a wide range of wetted materials
for most chemicals.
In summary, the OPTIMASS 7000 from KROHNE offers the fol-
lowing advantages:
• Universally applied due to a wide range of models
• Secondary containment complies with pressure equipment
guidelines
• User-friendly software Flow Toolbox.
For more information tel: +27 11 314 1391 or
go to
OPTIMASS 7000 – corrosion-resistant in
all applications