CASE STUDY
the pipeline’s perspective
Situation:
A large gas gatherer and processor in the DJ Basin
was experiencing frequent high oxygen events on its
system. The interstate pipeline taking gas from the
gatherer’s processing plant had an oxygen limit of
10 ppm in its tariff specifications, began to actively
enforce it, and at one point refused to take gas until
the oxygen level was back below the 10 ppm limit.
Consequently the gatherer began taking actions on its
system to find the sources. This was complicated by
the erratic and short-term nature of the oxygen events.
As a result of the inability to positively identify the
source(s), the gatherer took the unprecedented step
of asking all the producers to shut down any and all
tank-mounted vapor recovery systems, including
EcoVapor’s units. At this time, the oil producers
were incorporating vapor recovery towers operating
upstream of their oil storage tanks at low pressures
to “deaden” the oil before it entered the tanks. That
design was considered to be oxygen-free as it was
in a low but positive pressure environment.
Despite banning tank-mounted vapor recovery
systems and having producers adapt vapor tower
systems, the gatherer continued to experience
frequent oxygen events on its system. It became
clear that other systems and processes were also
introducing oxygen into the gas gathering system.
Eight months into the ban, EcoVapor’s staff met with
the gatherer with a plan to test our oxygen destruction
technology and to clearly establish that EcoVapor’s
units are as effective as advertised and prevent
oxygen from entering the gas gathering system while
recovering the high Btu, high value gas from the oil
storage tanks.
A single, isolated pad site with eight multiple horizontal
wells and conjoined storage tanks was chosen for the
test. The site produced significant oil volumes with
multiple loads being hauled each day, which, in turn,
loaded the tanks with air every time they were emptied.
This was a solid challenge for an EcoVapor unit.
EcoVapor
Recovery
Systems
Only ERS incorporates active oxygen
destruction technology and calibrated
monitoring systems that together allow
all the flash gas to be recovered, not
burned at the site and wasted.
Based on the VOC incinerator model and inlet
pressure/volume curves, it was determined that an
ERS 70 MCFD unit would best fit the application. The
ERS 70 is equipped with a 34 HP EPA certified Zenith
engine, which helped reduce the time and effort to
obtain an air permit for the site. The ERS unit was tied
in to the vent line leading from the storage tanks to the
VOC incinerators, started up, and the tank pressures
declined from 14 oz to 2 oz, extinguishing the flames in
the incinerators in the process.
The ERS onboard oxygen analyzer records data every
10 seconds. During the initial 30 day test, oxygen in
the gas sales volumes averaged under 2 ppm despite
frequent oil hauling and occasions where hatches were
not closed immediately. For their verification process,
the gas gatherer took samples of the gas coming
through their sales meter and used a portable analyzer.
Summary:
After five months, the initial test unit continued to
deliver gas well with oxygen levels below the pipeline
specification. A second ERS was then installed on a
different site with the same level of performance.
Conclusion:
Despite claims that vapor removal/recovery systems
installed upstream of the oil storage tanks are in an
oxygen-free environment, gas gatherers continue to
see frequent high oxygen events. EcoVapor’s units are
designed to recover gas known to contain oxygen and
process the stream such that virtually no oxygen is
delivered into the pipeline. Only ERS incorporates
active oxygen destruction technology and calibrated
monitoring systems that together allow all the flash gas
to be recovered, not burned at the site and wasted.
Peter Mueller, CEO
[email protected]
www.ecovaporrs.com