Chemical Engineering January 2017 - 20

Endress+Hauser
FIGURE 4. With Endress+Hauser's Heartbeat Technology, the new Proline generation of flowmeters offers
diagnostic coverage from the measuring tube to the outlet. This ensures a low residual risk of a passive
protection failure
Steven Craig, international sales
manager with FCI.
One of the most prevalent standards
related to flow equipment is
SIL safety, as outlined in various IEC
standards, which look at the failure
rate of equipment and manufacturing
techniques of the instrument to
ensure safety in applications. Process
and plant engineers with operations
that require IEC 61511 compliance
can employ FCI's ST51A and
ST75A thermal mass flowmeters for
air/gas flow measurement applications.
Both meet SIL 1 compliance
standards. ST51A is an insertionstyle
flowmeter designed for use in
pipe diameters larger than 2 in. and
is optimized for flow measurement of
air, compressed air, nitrogen, natural
gas, digester gas and other biogases.
ST75A is an inline instrument
designed for pipe diameters from
0.25 to 2 in. for applications in air,
all inert gases, natural gas and other
hydrocarbon gases.
Nathan Hedrick, flow product
marketing manager with
Endress+Hauser (Houston; www.
us.endress.com) agrees that safety
is a challenge and that compliance
with current industry ratings
provides flow equipment users
with the assurance they need that
their instruments will operate reliably
and safely in their applications.
" Quality is a pre-requisite of
both safety and availability. There
must inherently be quality in the
20
design and manufacture of a device
that follows good engineering
practices and international metrology
standards, " he says. " Without
this, a chemical processor cannot
have confidence in the ability of the
device to produce an accurate and
reliable measurement, to operate
as required in a safety critical application
or to ensure maximum plant
and process availability. "
For safety applications, flowmeters
must meet the highest requirements
in terms of reliability. With E+H's
Heartbeat Technology, the new Proline
generation of flowmeters (Figure
4) offers diagnostic coverage from
the measuring tube to the outlet.
This ensures a low residual risk of a
passive protection failure. Traceable
factory calibration and redundant
internal references complement the
safety-by-design principle with minimal
failure rates in accordance with
IEC 61508.
In chemical and petrochemical
companies, flowmeters must
ensure maximum reliability. Although
costly, proof testing is the
established method for validating
functional reliability. Heartbeat
Technology provides the basis for
minimizing the effort and exposure
of personnel involved in these routine
activities.
Increased versatility
In the real world, process changes
come via plant upgrades, retrofits
and expansions. According to Dan
Cychosz, global product management,
DP Flow products with Rosemount,
these can change flowrates
and required material compositions
from original specifications for both
process and utility applications.
" Using a flow instrument that has
the flexibility to accommodate these
changes without replacement reduces
the cost of these projects, "
he says. " It also has the day-to-day
benefit of providing accurate flow
measurements during unintended
changes such as process upsets. "
Technological advancements such
as Emerson's Rosemount Ultra for
Flow allow traditional DP flow installations
to accommodate a much
wider range than older technologies.
Rosemont's McCulloch says: " Being
able to have a transmitter with an
accuracy specified as a percent of
reading is crucial in many applications.
Users can standardize on one
product for a variety of applications
because this approach extends the
range of accuracy over a broader
turndown ratio. This helps customers
eliminate the need to change out
primary elements due to seasonal
flow changes or eliminates the need
for stacked transmitters due to varying
flowrates. "
Jesse Arenstein, lead applications
engineer and engineering
product manager with Alicat Scientific
(Tucson, Ariz.; www.alicat.
com) agrees that flow needs in the
chemical industry change often,
making it necessary to program gas
mixtures on the fly. In an effort to
eliminate what is sometimes called
" disposable flow instruments " that
don't accommodate changes, Alicat
offers Gas Select Composer
onboard firmware for its mass flowmeters
and controllers. Composer
is a gas-composition feature that
allows users to define up to 20
custom gas compositions with up
to five constituent gases per mix.
Setting Gas Select to the appropriate
gas that is flowing guarantees
the NIST-traceable accuracy of
measurement for that gas. The Gas
Select functionality precludes the
need for correction factors and also
allows the user to change between
gases, without needing to change
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Chemical Engineering January 2017

Table of Contents for the Digital Edition of Chemical Engineering January 2017