Chemical Engineering January 2023 - 9

New pressure-relief valves improve
performance and reduce emissions
S
pring-loaded pressurerelief
valves (PRVs) often
use bellows to ensure
balanced operation.
Data analysis from 30,000 PRV
service records across different
industries and valve brands
shows a bellows
failure rate
CIC-10307 halfp page ad.qxd 3/25/07 6:19 PM Page 1
between 2 to 6%, according to
Emerson (St. Louis, Mo.; www.
emerson.com). The most common
causes of bellows failures
are excessive backpressure
and rapid cycling. Ruptured
bellows will cause fugitive emissions
and may prevent valve
operation at the designed set
pressure, with the risk of catastrophic
overpressure events.
To address these issues, Emerson
introduced two new technologies
for its Crosby J-Series
PRV line. The first is a Balanced
Diaphragm, which eliminates the
need for bellows in PRVs, while
providing balanced operation
against backpressure. Its design
extends the backpressure limits
from 60% to 80%, and increases
the backpressure correction factor,
Kb, by up to 15%, expanding
the application range of springloaded
PRVs. Extending the
backpressure limit and increasing
the Kb factor often permits
the use of smaller valves, the
company says.
The second technology is Bellows
Leak Detection, enabling
remote detection of bellows ruptures
in PRVs, with the capability
to reduce and accurately calculate
volumetric emissions in real
time. It consists of a backup piston
and a Rosemount wireless or
wired pressure transmitter. The
backup piston can reduce emissions
by over 90% in the event of
a bellows rupture because it has
a much smaller clearance than a
standard bonnet vent, and it ensures
balanced operation.
ity improve as it gets colder - contrary to most other
materials in existence.
The team, led by researchers from Lawrence Berkeley
National Laboratory (Berkeley Lab; Calif.; www.lbl.gov)
and Oak Ridge National Laboratory (Tenn.; www.ornl.
gov), published a study describing their record-breaking
findings in Science last month.
CrCoNi is a subset of a class of metals called high-entropy
alloys (HEAs). All the alloys in use today contain a high proportion
of one element with lower amounts of additional elements
added, but HEAs are made of an equal mix of each
constituent element. These balanced atomic recipes appear
to bestow some of these materials with an extraordinarily
high combination of strength and ductility when stressed,
which together make up what is termed " toughness. "
The toughness of this material near liquid helium temperatures
(20K; -424°F) is as high as 500 MPa.m1/2, which
is about five times higher than some of the best steels.
ADSORBING NITRATES
Nitrate ions released into water bodies due to human
activities can have adverse effects on aquatic and terrestrial
ecosystems. Conventional adsorption materials that
are used for treating water contamination are incapable
of removing nitrate. To deal with this issue, researchers
from Chiba University (Japan; www.chiba-u.ac.jp) have
developed functionalized carbon fibers that exhibit excellent
nitrate adsorption properties, as reported in a recent
issue of SN Applied Sciences.
" Carbonaceous materials like activated carbons are usu(Continues
on p. 10)
PLASTIC CONTROL VALVES FOR
ALL YOUR CORROSIVE APPLICATIONS
Collins plastic control valves are
highly responsive control valves
designed for use with corrosive
media and/or corrosive atmospheres.
Collins
valves feature all-plastic
construction with bodies in PVDF,
PP, PVC and Halar in various body
styles from 1/2 " - 2 " with Globe,
Angle or Corner configurations and
many trim sizes and materials.
Valves may be furnished without
positioner for ON-OFF applications.
Call for more information on our
plastic control valves.
P.O. Box 938 * Angleton, TX 77516
Tel. (979) 849-8266 * www.collinsinst.com
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
For details visit adlinks.chemengonline.com/84643-04
JANUARY 2023
9
https://www.lbl.gov https://www.ornl.gov https://www.emerson.com https://www.chiba-u.ac.jp http://adlinks.chemengonline.com/84643-04 http://WWW.CHEMENGONLINE.COM
Chemical Engineering January 2023

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