Low Odorant Issues
Prepared for Northeast Gas Association
April 11, 2013
ON IT
Mercaptan
• Found in Nature
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Skunk spray
Skunky beer
Garlic
Released from decaying organic matter
Produced when humans digest asparagus
• Low odor threshold
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0.5 ppb = 0.0005 ppm
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Odorant Fade
• Occurs when the level of odorant in the gas is reduced due
to physical and/or chemical processes including adsorption,
absorption and oxidation.
– Oxidation
– New pipe
– Gas Quality
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Odorant Masking
• Odor masking is the change in perception to odor rather
than an actual disappearance of odor.
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Hydrogen sulfide
Unsaturated hydrocarbons
Aromatic hydrocarbons (e.g., BTEX)
Amines – used to remove Hydrogen Sulfide
Alcohols and Glycols – used to remove water
Wellhead additives
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Odorant Incidents
• Timeline – October 12, 2011 – November 23, 2011
• Incidents – no odor, low sulfur & unstable odorant readings
• Reduced supply from Tennessee Pipeline Co.
• Notifications made
• Determine boundaries
• Leak surveyed transmission, HP supply main in the
affected areas
• Restricted contractor activity near transmissions mains
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Task Group Action Plan
Root Cause Analysis
• Root Cause – Unstable odorant levels caused by odorant fade NOT odorant masking
• Basis
- No evidence of odorant masking
- Glycol found in Tennessee system, but levels were small and consistent from
October 2011 to October 2012
- Odorant levels were stable and acceptable from January 2012 to October 2012 with
the presence of the same amount of glycol
- Production facility audits revealed processes had no evidence of infiltration of
masking agents
- Evidence of odorant fade during October 2011 – November 2011
- Lack of odorant injection due to inoperable Tennessee injection pump
- Fluctuations in odorant injection rates
- Installation of 54 miles of new, “un-pickled” Tennessee pipe
- Tennessee maintenance pigging
- Taking out/placing into service Tennessee line 334-336
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Odorant Injection Unit
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Issues related to mercaptan injection
• Regulatory
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Required an emergency action plan
Required spill response training
• Leak response in area of injection site
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Training of GDS
• Spills
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Significant odor complaints
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Scentinel E
• tert-Butyl Mercaptan
• Isopropyl Mercaptan
• N-Propyl Mercaptan
• Hazard Class
77%
16%
6%
tert- Butylmercaptan (TBM)
Health – 2
Fire – 3
Reactivity - 0
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Characteristics of Sentinel E
• Extremely odorous
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Odor Threshold of 0.5 ppb
In the immediate area of the spill >5 ppm and up to >25 ppm 10,000 to 50,000 times odor threshold.
• Low Flashpoint
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-0.4º F.
Regulated as a Flammable liquid.
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Physical/Chemical Properties
FLAMMABILITY
Product
Name
Hazard
Class
UN
Placard Guide No.
Guide No.
Number
Scentinel A
3 - Flammable
Liquid
UN 2363
Scentinel E
3 - Flammable
Liquid
UN 3336
Scentinel F
Series
3 - Flammable
Liquid
UN 3336
Scentinel S
Series
3 - Flammable
Liquid
UN 3336
130
130
130
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An Uncontrolled Release of Odorant Can
Occur:
• During transfer from a cylinder or bulk delivery trailer to the
odorant storage tank
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A spill response vendor was on location for all activities involving
odorant at the station.
• If there is a failure of the odorizer mechanical system
• If there is deliberate vandalism or sabotage
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Impacts of an Odorant Release
• Evacuation of surrounding area
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Initial evacuations:
• Incidental release - <.25 pints.
– The facility fence line.
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PPE requirements
Air purifying respirator for odorometer readings >0.5ppm but < 25 ppm
Half face respirator with organic filters for readings ≥ 0.5ppm but ≤ 5ppm
Full face respirator with organic filters for readings ≥ 5 ppm but < 25 ppm
CRFR coveralls, heavy duty rubber boots, nitrile inner gloves, hard
hat.
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Impacts of an Odorant Release
• Evacuation of surrounding area
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Initial evacuations:
• Incidental release - <.25 pints.
– The facility fence line.
• >.25 pints to 50 gallons
– 150’ radius from spill
• PPE requirements
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Self Contained Breathing Apparatus(SCBA) or airline respirators for
readings ≥ 25ppm
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CRFR coveralls, Rubber boots, Nitrile gloves, Hard hat.
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Impacts of an Odorant Release
• Evacuation of surrounding area
–
Initial evacuations:
• Incidental release - <.25 pints.
– The facility fence line.
• >.25 pints to 50 gallons
– 150’ radius from spill
• > 50 gallons
– 150’ radius from the spill
– 1000’ downwind (initial evacuation)
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Impacts of an Odorant Release
• Evacuation of surrounding area
–
Initial evacuations:
• >.25 pints to 50 gallons
– 150’ radius from spill
• > 50 gallons
– 150’ radius from the spill
– 1000’ downwind
• Greater than incipient stage fire
– ½ mile radius
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Impacts of an Odorant Release
• Significant increase in odor complaint calls
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Up to 6 miles from the spill
Up to several days after the spill is cleaned
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Leak Response
• Created an emergency action plan
• Notified police and fire department
• Trained Con Edison First Responders –
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Notify Control Room
Setup initial evacuation zones:
• Trained a spill response team
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Voluntary HazMat Technicians
• Provided training to our spill response vendor
• Staged spill response supplies
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Questions?
Prashanth Kadaba-Srinivasan
Email: [email protected]
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