Hydrocarbon Processing - June 2022 - GP-40

ENVIRONMENT & SAFETY
risk of igniting a potential
cloud of RNG
° Design deflagration venting
panels on the building to mitigate
the severity of an explosion
FIG. 5. Compressor building explosion in
Springville, Pennsylvania.10
A small failure of the compressor equipment
can quickly provide the flammable
concentration required for the explosion.
Several incidents have occurred at
natural gas compressor stations, which
are comparable to RNG compressors.
For example, in Springville, Pennsylvania
in 2012,10
a valve was left open and
the compressors were started up after
maintenance. Within minutes, the building
filled with natural gas and exploded
(FIG. 5). The gas detection system isolated
the feed and discharge lines from
the compressors and alerted personnel
to evacuate. No injuries were reported
and only one of the six compressors was
severely damaged, due to the mitigation
controls and alarms in place at the facility.
Safeguards and mitigations include:
* Consider the use of a weatherized
compressor so it can be outdoors
or under a roof structure but not
within walls
* If you choose to have compressors
indoors, these additional mitigation
options should be reviewed and
considered for implementation to
meet desired risk tolerance:
° Provide general building
ventilation to mitigate small
releases of RNG
° Provide adequate gas detector
coverage to accompany the
automatic shutoff of feed gas and
shutdown of compressors
° Provide automatic shutoff of
RNG feed to compressors as
well as automatic shutdown of
compressors on gas detection to
limit the inventory available for
release into the building
° Design processes with
equipment that meet the
standards for a Class 1, Div. 1
hazardous area to mitigate the
40 MAY/JUNE 2022 | GasProcessingNews.com
* Relocate occupied spaces such
as control rooms, maintenance
offices or other occupancies to
separate buildings away from the
compressor structure to reduce
population vulnerability.
Recommended assessments. Examples
of the type of studies that are helpful
in the understanding of hazards and
risk from the operation of RNG plants
include:
* A facility siting study (FSS) and
quantitative risk assessment
(QRA): These studies are used
to model and assess hazards
associated with operation of the
facility and evaluate the associated
risk of those hazards to personnel
onsite. An FSS/QRA can assess
the risks to personnel associated
with site operations, such as AD
explosion, over-pressure rupture,
biogas release and compressor
confined-vapor cloud explosion.
* A hazardous area classification
(HAC) study is used to define
hazardous areas for electrical
classification inside of the
compressor building and near the
AD tanks.
* A pressure relief valve (PRV)
dispersion study is useful to
accompany an HAC study because
intentional releases from a PRV
can become ignition sources to the
internal explosion of ADs, based on
historical incidents.
* Ventilation design studies are
performed to determine the
minimum required air exchange
rate to ensure adequate ventilation
to mitigate confined vapor cloud
explosion hazards posed by
small releases.
* A fire and gas (F&G) detection
study evaluates whether a
particular hazardous gas release
and/or fire radiation can be
detected considering the
device location in relation to
the hazardous release scenario.
Adequate detection is pertinent
in the automation of safeguards
6
LITERATURE CITED
1
Tanikawa, S., " Fact sheet | Biogas: Converting
waste to energy, " Environmental and Energy Study
Institute (EESI), October 2017, online: https://
www.eesi.org/papers/view/fact-sheet-biogasconverting-waste-to-energy
2
U.S.
Environmental Protection Agency (EPA), " An
overview of renewable natural gas from biogas, " EPA
456-R-20-001, July 2020.
3
Wiss, J., " Calumet water reclamation plant-
Investigation of explosion and structural collapse
in gravity belt thickener room, " Elstner Associates
Inc., prepared for Metropolitan Water Reclamation
District of Greater Chicago, November 16, 2018.
4
Walsh, T., " Calumet water reclamation plant explosion
and building collapse: Lessons learned, " Fire
Engineering, June 2020, online: https://www.fireengineering.com/industrial-firefighting/calumetwater-reclamation-plant-explosion-and-buildingcollapse-lessons-learned/
5
Hines,
M., et al., " Microaeration for hydrogen sulfide
removal in biogas, " University of Maryland,
2019, online: https://projects.sare.org/wp-content/
uploads/In-situ-microaeration-Fact-sheet.pdf
Krakat, N., et al., " Methods of ammonia removal
in anaerobic digestion: A review, " Water
Science & Technology, iWA Publishing, July 2017,
online: https://iwaponline.com/wst/article/76/8/1925/19195/Methods-of-ammoniaremoval-in-anaerobic-digestion
7
" A
review of environmental incidents at anaerobic
digestion (AD) plants and associated sites between
2010 and 2018, " Environmental Agency 2018,
September 2019.
8
" Sludge power plant collapses in Shropshire, "
Shropshire Star, May 2014, online: https://www.
shropshirestar.com/news/2014/05/30/shropshiresludge-power-plant-collapses/
9
Wilkinson,
H., " Sludge tank and anaerobic digester
corrosion maintenance, " Belzona, November 2018,
online: https://blog.belzona.com/tank-anaerobicdigester-corrosion/
10
Tanfani,
J., " Northern Pennsylvania gas explosion
was out of regulatory reach, " The Philadelphia
Inquirer, April 2012, online: https://www.inquirer.
com/philly/business/20120408_Northern_
Pennsylvania_gas_explosion_was_out_of_regulatory_reach.html
MEGAN
YOUNG is a Project I
Consultant in the Chicago Process
Safety Group, specializing in
consequence and risk modeling.
Ms. Young has worked extensively
on these projects with clients in
the chemical processing industry
with a focus on risk quantification, refinement and
mitigation of blast, toxic, flammable and fire hazards.
to mitigate hazards as well as to
prevent spurious trips.
* SIS/SIL evaluations are used to
verify the safeguards in place and
sufficient testing intervals
to achieve SIL target.
* Based on the National Fire
Protection Agency (NFPA) 68
standard, perform a vent panel
study to design the potential
mitigation for overpressures from a
confined vapor cloud explosion. GP

https://www.eesi.org/papers/view/fact-sheet-biogasconverting-waste-to-energy https://www.eesi.org/papers/view/fact-sheet-biogasconverting-waste-to-energy https://www.eesi.org/papers/view/fact-sheet-biogasconverting-waste-to-energy https://www.fireengineering.com/industrial-firefighting/calumet-water-reclamation-plant-explosion-and-building-collapse-lessons-learned/ https://www.fireengineering.com/industrial-firefighting/calumet-water-reclamation-plant-explosion-and-building-collapse-lessons-learned/ https://www.fireengineering.com/industrial-firefighting/calumet-water-reclamation-plant-explosion-and-building-collapse-lessons-learned/ https://www.fireengineering.com/industrial-firefighting/calumet-water-reclamation-plant-explosion-and-building-collapse-lessons-learned/ https://projects.sare.org/wp-content/uploads/In-situ-microaeration-Fact-sheet.pdf https://projects.sare.org/wp-content/uploads/In-situ-microaeration-Fact-sheet.pdf https://iwaponline.com/wst/article/76/8/1925/19195/Methods-of-ammoniaremoval-in-anaerobic-digestion https://iwaponline.com/wst/article/76/8/1925/19195/Methods-of-ammoniaremoval-in-anaerobic-digestion https://iwaponline.com/wst/article/76/8/1925/19195/Methods-of-ammoniaremoval-in-anaerobic-digestion https://www.shropshirestar.com/news/2014/05/30/shropshire-sludge-power-plant-collapses https://www.shropshirestar.com/news/2014/05/30/shropshire-sludge-power-plant-collapses/ https://www.shropshirestar.com/news/2014/05/30/shropshire-sludge-power-plant-collapses https://blog.belzona.com/tank-anaerobicdigester-corrosion/ https://blog.belzona.com/tank-anaerobicdigester-corrosion/ https://www.inquirer.com/philly/business/20120408_Northern_Pennsylvania_gas_explosion_was_out_of_regulatory_reach.html https://www.inquirer.com/philly/business/20120408_Northern_Pennsylvania_gas_explosion_was_out_of_regulatory_reach.html https://www.inquirer.com/philly/business/20120408_Northern_Pennsylvania_gas_explosion_was_out_of_regulatory_reach.html https://www.inquirer.com/philly/business/20120408_Northern_Pennsylvania_gas_explosion_was_out_of_regulatory_reach.html http://www.GasProcessingNews.com

Hydrocarbon Processing - June 2022

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