Hydrogen Sulfide (H2S) in the Downstream Oilassevirtualclassroom.org/safetydownstreamattendeearea/wp-content/... · RJR Safety Inc 1 Hydrogen Sulfide (H2S) in the Downstream Oil &

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Hydrogen Sulfide (H2S) in the Downstream Oil &

Gas Industry

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Agenda  Describe physical characteris�cs of Hydrogen Sulfide  Iden�fy poten�al sources of H2S  Review the hazards of Hydrogen Sulfide  Discuss basic safe work prac�ces  Iden�fy basic methods for elimina�ng or controlling H2S

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Resources & References

 API RECOMMENDED PRACTICE 55   “Recommended Prac�ce for Oil and Gas Producing and Gas Processing Plant Opera�ons Involving Hydrogen Sulfide” (March 2007)

 ANSI Z390.1   “Accepted Prac�ces for Hydrogen Sulfide (H2S) Training Programs”

 Hydrogen Sulfide Management -‐ Mi�ga�on op�ons in petroleum refining, storage and transporta�on (white paper)   h�p://www.bakerhughes.com/news-‐and-‐media/resources/white-‐papers/hydrogen-‐whitepaper-‐060210

 OSHA Regula�ons 1910 & 1926  MSDS & NIOSH Pocket Guide to Chemical Hazards

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Downstream Oil & Gas Industry

 Processing and refining of oil  Process and purifying of natural gas

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HYDROGEN SULFIDE  One of the most deadly hazards found in the oil and gas field  Signal Word (HAZCOM 2012): “Danger”   Immediate definite hazard!

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Health 4

Fire 4

Reactivity 0

PPE

4

4

0

0

Physical Characteristics of Hydrogen Sulfide

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Hydrogen Sulfide Synonyms “AKA”

 Sulphureted hydrogen  Hydro-‐sulfuric acid  Di-‐hydrogen sulfide  Ro�en egg gas  Swamp gas  Meadow gas  S�nk damp  Devil’s Breath

 H2S RJR Safety Inc 7

Normal Physical State  Highly toxic  Colorless gas  Vapor Density = 1.19 at 32 degrees F

  Slightly heavier than air (Air = 1)  Auto-‐Igni�on Temperature: 500 degrees F

 Minimum temperature a substance ignites without a flame or spark  Flash Point: -‐76.4 degrees F

  Lowest temperature at which a flammable liquid gives off sufficient vapor to form an ignitable mixture with air near its surface or within a vessel;   Combus�on does not con�nue

 Flammability Limits: 4.3% – 46% vapor by volume in air  Soluble in liquids such as water, gas, and oil

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Other Properties Combus�bility  Burns with a blue flame  Produces sulfur dioxide (SO2)  Smells of sulfur  Colorless gas  Vapor Density = 2.26 at 32 degrees F  Heavier than air (2X+)

Odor & Warning Proper�es  Ro�en egg odor  Easily detected at low concentra�ons  Olfactory fa�gue and paralysis (loss of the sense of smell)  Do not use odor/sense of smell as the warning for the presence of H2S

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Potential Sources of Hydrogen Sulfide

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Oilfields - Drilling & Production Mines Volcanoes

By-Product of Chemical Process   Pulp/Paper Industry Felt Makers   Oil refining & gas processing

Fishing Industry Tanneries Municipal Sewers Landfills

Origins of Hydrogen Sulfide

Sources of H2S

Naturally Occurring

  Sour gas   Sour crude oil  Decomposi�on of bacteria in stored water

Processing, Refining, & Storage   Sour gas & sour crude oil  Refineries and storage facili�es, such as tank farms   Refining or storing of crude oils, intermediates (condensates, napthas, light dis�llates, gas oils and residual materials), and refined products that contain H2S

 Heavy oils, including crude oil, residual fuel and gas oil  When stored in large quan��es for an extended �me

  Light hydrocarbon products may be contaminated during the dis�lla�on or refining process

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Locations  Processing equipment

  Pipelines, pumps, towers, columns, compressors, heaters, strippers   Storage equipment

  Tank farms, pipelines, pumps, compressors,  Water processing units in refineries & plants

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Hazards of Hydrogen Sulfide

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HYDROGEN SULFIDE  One of the most deadly hazards found in the oil and gas field  Signal Word (HAZCOM 2012): “Danger”   Immediate definite hazard!

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Health 4

Fire 4

Reactivity 0

PPE

4

4

0

0

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 Toxic – deadly in low concentra�ons  Highly Flammable  Explosive Range of 4.3% to 46%  Automa�cally ignites at 500 degrees F   Cigare�e burns at 1500 deg F

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 Heavier than air  Vapor Density = 1.19  Air = 1  Readily moved around by the wind

  Liquid Soluble   In both water and liquid hydrocarbons   Dissolves in water forming a weak acid   Heat and agita�on causes H2S gas to be

released from fluids.

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General Personnel Hazards

 H2S deadens the sense of smell at concentra�ons as low as 30 ppm  Death can occur with a few breaths at low concentra�ons of 700 ppm  Hydrogen Sulfide collects in low lying areas and confined spaces

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Hazards of Hydrogen Sulfide  H2S contac�ng strong oxidizers and oxidizing materials may cause fire or explosions  H2S can react with iron or steel to form iron sulfide  Pyrophoric -‐ able to ignite spontaneously on contact with air

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Storage Hazard  Hydrocarbons containing even a few small amounts of H2S can produce excessive concentra�ons of H2S in the headspace of tanks Example  H2S is typically a gas during storage  Agita�on, increased temperatures can increase concentra�on in vessel headspaces with the release of the H2S from the liquid  As a tank fills with sour gas/sour crude oil, the headspace decreases and the H2S concentra�on increases

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Equipment hazard  H2S dissolves in water and forms a weak acid that can corrode and pit metals  H2S is highly corrosive and can degrade both process and storage equipment  Increases the difficulty and cost of integrity management programs

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Equipment hazard  Storage Tank & Pipe Corrosion  H2S readily dissolves in condensed water to form bisulfide (type of salt) that is corrosive to carbon steel  Storage tanks used to store hydrocarbons with large concentra�ons of H2S are very suscep�ble to this corrosion  Iron sulfide deposits are created and adhere to storage tank walls and develop into severe pi�ng corrosion  Metals become bri�le and crack due to iron sulfide deposits which reduces the life of the storage tank  The rate of corrosion depends on the following:

  Concentra�on of H2S   Turnover (load & unload) frequency   Large amounts of oxygen and salt water used to flush the tanks can become very corrosive

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LPG (Propane) Hazard  Liquefied Petroleum Gas (Propane) can be contaminated with H2S  Contaminated LPG can be corrosive to copper & copper alloys  LPG is required to be non-‐corrosive to copper because of the copper and copper alloys used in fuel systems  The presence of H2S is in LPG is a poten�al health hazard to consumers in a residence or workplace

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Environmental Hazards  Residen�al communi�es and hydrocarbon storage facili�es have become closer in proximity  Nuisance odors to surrounding communi�es exceeding either H2S emissions standards  Even with emission/environmental regula�ons in many areas

 Causing increased numbers of complaints about nuisance odors  Even in extremely small quan��es that are within the safety levels are s�ll unpleasant to the neighbors  Olfactory detec�on Hydrogen sulfide 0.0047 ppm

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Basic Safe Work Practices

to Protect Workers

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Hydrogen Sulfide Safety Training

 Properly trained employees and contractors per ANSI/ASSE 390.1 “Accepted Prac�ces for Hydrogen Sulfide Training”   Descrip�on of Hydrogen Sulfide   Sources & Loca�ons of Hydrogen Sulfide   Physical and chemical proper�es of H2S   Concentra�ons/Toxic Levels/Exposure levels  Health effects   Detec�on and Monitoring   Con�ngency and Emergency Response Plans   PPE – Respirators (SCBA and Escape hoods)   Safe Work Prac�ces

 All workplace/work environment specific

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Personal Protective Equipment  Respiratory Protec�on  Wri�en Program per 1910.134  Must be medically fit for respirator use  Medical Evalua�on Ques�onnaire (Mandatory)

  Appendix C, 1910.134  Fit tes�ng procedures  Respirator use  Cleaning & Maintenance  Training

 More specific & in-‐depth training is needed

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Respirator Selection

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•  SCBA: posi�ve pressure breathing equipment;

•  Full-‐face piece

Emergency Escape Respirator

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•  Turn the bo�le on, then the hood

•  Your first!!! •  5 minutes of air •  Escape only!!!

Methods of Detection   Fixed Monitor Systems   Lead acetate paper  Detec�on tubes  Personal Monitor  Portable Gas Detector

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  Assessing or Monitoring – Prepare for potential lethal concentrations – Use Respiratory Protection Equipment

Do not use your nose as a Detector!

Air Monitoring Equipment

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Fixed Monitor   Single or Mul�-‐gas Detector  Placed at poten�al exposure loca�ons  Data Logging  Visual Alarm

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API Recommended Practice  Ac�on Levels

  Hydrogen Sulfide 10 ppm   Sulfur Dioxide 2 ppm

  If concentra�ons could exceed Ac�on Levels   Detec�on devices shall be available on-‐site

Evacua�on Alarm at 10 ppm or 2 ppm Then prepare to work in the environments above 10 ppm H2S and 2 ppm S02

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Personal Monitors  Single Gas

 Hydrogen Sulfide (H2S)   Sulfur Dioxide (SO2)

 Badge-‐mount  Clip-‐mount  Audible Alarm

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 4 or 6-‐gas Monitors  Oxygen Content (O2)   Carbon Dioxide (CO2)   Lower Explosive Limit (LEL)  Hydrogen Sulfide (H2S)   Sulfur Dioxide (SO2)   Carbon Monoxide (CO)

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Detector Tubes  Similar to a Single Gas Detector  Tubes change color according to concentra�ons  “Grab Samples” – immediate reading only

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Wind Direction Indicators

 Windsocks, streamers, flags  Visible from anywhere on site  Illuminated areas  Assembly points/Briefing areas  Entrances to facili�es

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Warning Signs  Posted at appropriate loca�ons such as:  Entrance points for sites or opera�ons where Hydrogen Sulfide may be encountered

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Contingency & Emergency Response Plans

 Aler�ng of on-‐site personnel – company & contractor  Accoun�ng of on-‐site personnel – company & contractor  Immediate ac�ons/responsibili�es for on-‐site workers  Shut-‐down of non-‐essen�al equipment & processes  Opera�ng cri�cal equipment  Immediate emergency ac�ons – rescue, medical

 No�fica�on of company management  No�fica�on of public safety officials

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Basic Methods for Eliminating or

Controlling Hydrogen Sulfide

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Design & Construction  Tanks and vessels manufactured in accordance with ASME Boiler and Pressure Code  Piping systems to designed and constructed according to applicable ANSI standards (B31.3, B31.4, or B31.8)  Follow the specifica�ons in NACE Standard MR0175 for produc�on and processing plants with hydrogen sulfide  NACE Interna�onal was Na�onal Associa�on of Corrosion Engineers  NACE Standard MR0175

  Establish process limits for H2S pressures as precau�ons against sulfide stress cracking (SSC)   Provides guidance for the selec�on and specifica�on of SSC-‐resistant materials   Provides applica�on limits for some corrosion-‐resistant alloys

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Eliminating/Controlling

 Storage  Government agencies have implemented many regula�ons:  Capping the amount of H2S a product may contain  Capping the amount of headspace a storage vessel may contain

 Regula�ons may be driven by air pollu�on legisla�on  Manage H2S keeping storage temperatures and tank volumes low to minimize the concentra�on of H2S in the headspace

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Eliminating/Controlling

 Flare Gas  Many U.S. refinery flare gas systems are affected by environmental regula�ons that limit H2S content in fuel gases sent to combus�on devices  For refineries to reduce SO2 emissions and avoid noncompliance issues, it is common to treat the flare gas with scavengers to reduce the amount of H2S it contains.

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Eliminating/Controlling  Liquefied Petroleum Gas (LPG)  LPG that contains H2S could be handled by reprocessing it to remove the H2S – �me consuming and �es-‐up storage   Use of water-‐soluble H2S scavengers to remove hydrogen sulfide from LPG  May reduce the quality of the fuel by introducing moisture

 Oil-‐soluble H2S scavengers are typically used so as not to affect cri�cal fuel proper�es and will not add water (and possibly a haze) to a finished fuel

 Crude and heavy residual oils  Treated with an H2S scavenger before transport to the refinery, being placed in storage, or when being transferred between facili�es.

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Eliminating/Controlling  Chemical Treatments  Many chemicals will readily react with H2S, including caus�c, peroxides, formaldehyde, nitrites and many types of amines conver�ng the H2S into other sulfur compounds

 Scrubber Systems  Using a series of columns and chemicals to remove or “scrub” the H2s from the hydrocarbon

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Eliminating/Controlling   Specialty chemical conversion reagents (Scavengers)

  A common method for removing H2S from hydrocarbon streams is to use a chemical conversion reagent – scavenger.   The addi�ve reacts with H2S irreversibly to form other chemicals that are more easily removed or the other chemical can stay in the hydrocarbon without effec�ng the quality of the gas or oil

 Water-‐soluble scavengers  Oil-‐soluble scavengers  Metal-‐based scavengers

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Summary  Described physical characteris�cs of Hydrogen Sulfide  Iden�fied poten�al sources of H2S  Reviewed the hazards of Hydrogen Sulfide  Discussed some basic safe work prac�ces  Iden�fied basic methods for elimina�ng or controlling H2S

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QQuueessttiioonnss oorr CCoommmmeennttss??

“Working Safe, Preventing Injuries, Protecting Profits” RRJJRR SSaaffeettyy IInncc..

Contact Information: Wayne Vanderhoof CSP

[email protected] www.rjrsafety.com

724-809-4234

TThhaannkk yyoouu!! (This concludes the webinar)

“Working Safe, Preventing Injuries, Protecting Profits” RRJJRR SSaaffeettyy IInncc..

Contact Information: Wayne Vanderhoof CSP

[email protected] www.rjrsafety.com

724-809-4234

Hydrogen Sulfide (H2S) in the Downstream Oilassevirtualclassroom.org/safetydownstreamattendeearea/wp-content/... · RJR Safety Inc 1 Hydrogen Sulfide (H2S) in the Downstream Oil &

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