Hydrocarbon Processing - August 2021 - 24

Valves, Pumps and Turbomachinery
the levels of fugitive emissions. Once the
leaks are identified, the plant will usua
low-E valve is in the EPA consent decrees-that
determination is left up to
Valves certified as " low-E " are ideal to reduce fugitive
emissions, whether they are specified for a new system
or added to enhance an LDAR program. Installing low-E
valves before the EPA finds high fugitive emission levels
can save plants significant money by avoiding costly refits.
ally implement one or a combination of
the following methods to reduce fugitive
emissions levels:
* Institute a comprehensive plan
whereby leaks are identified
through in-situ testing of
valves and other connections
using EPA Method 21
* Identify, document and repair
leaks within a defined time frame
* Lower allowable leak limits for
valves, connections and pumps.
Improved LDAR strategies often also
include the stipulation that any new
valves installed must be low-E valves.
Interestingly, there is often no single
specified method for determining what
the processing plant or refinery in question.
In most cases, there are several options
for deciding what a low-E valve is,
and it frequently encompasses the plant
accepting one of the two following methods
for classifying valves as low-E:
1. A written guarantee that the
valve will not leak above 100
parts per million (ppm) for 5 yr
2. A written guarantee, certification
or equivalent documentation
stating that the valve has
been tested pursuant to
generally accepted good
engineering practices and has
been found to be leaking at
no greater than 100 ppm.
It can be challenging to understand the
difference between those two options,
so the following will examine
them in greater detail, highlighting
both the advantages
and disadvantages of each.
Written guarantee by the
manufacturer. To document
the purchase of low-E
valves, a plant could have the
manufacturer provide a written
guarantee that the valves
will not leak more than 100 ppm for 5 yr.
However, the problem with this idea is
that the plant operator needs to think
about what will happen if the valves do
leak. Will any compensation be involved,
or will the manufacturer simply replace
the leaky valve? Can the plant operator
recoup the costs associated with the
valve replacement?
If the leakage incident triggers an
EPA-levied fine (which can often be as
high as $10,000/d per incident), what
recourses would the plant operator have
to cover all the costs involved? Would the
manufacturer cover these costs, as well?
Many uncertainties are involved with
a manufacturer's guarantee, especially
when tests exist that can reveal if valves
are working as promised.
Low-emissions testing. Industry associations
like the American Petroleum
Institute (API) and the International
Standards Organization (ISO) have developed
actual tests to certify valves as
" low-emissions " equipment. These tests
include the following:
* API 624, Type Testing of Rising
Stem Valves Equipped with
Graphite Packing for Fugitive
Emissions: This test covers rising
stem valves, using methane as
the test media. The valve must
perform 310 cycles, along with
three thermal cycles (where
the valve is tested at ambient
temperature, at an elevated
temperature, and then again at
ambient temperature), with a leak
rate under 100 ppm methane.
FIG. 2. Installing low-E valves before the U.S. EPA finds high fugitive emissions levels can save
plants significant money in the long run by avoiding costly refits.
24 AUGUST 2021 | HydrocarbonProcessing.com
* API 641, Testing of QuarterTurn
Valves for Fugitive
Emissions: This testing involves
ball valves, using methane as the
test media. Each valve tested must
perform 610 cycles, along with

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Hydrocarbon Processing - August 2021

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