Chlorination/Ammoniation Setup Safety - PowerPoint Presentation

Slide1

Chlorination/Ammoniation Setup Safety

Patrick UrbankowskiDrexel UniversityMay 2018Adapted from Boris Dyatkin’s presentation

Slide2

Disclaimer

If you will conduct experiments that involve either ammonia or chlorine gases, you MUST

receive training, a fit test, and receive your own respirator provided by the Department of Environmental Health & Safety (

EHS

) and

Med-Tex Services. This must be repeated annually.Contact Joe Nihill (jrn43@drexel.edu)Must be clean-shaven prior to testing.Purge tubes with inert gas (e.g. Ar) prior to ammoniation or chlorination.

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Ammoniation

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Ammonia Handling

Airgas

Ammonia is a combination of liquefied air and hydrogen

N

2

+ 3 H

2



2 NH

3

In tanks, anhydrous ammonia is liquid.

When released from a tank, the liquid transforms to gas.

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Ammonia is all around (and in) us

Airgas

In small amounts, ammonia is one of the building blocks of mammal life

Ammonia is not a metabolic poison

Not determined to be a carcinogen

It is still, however,

lethally dangerous

.

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Detecting ammonia

Airgas

The most recognizable property of ammonia is:

Smell

Strong and irritating smell is the best warning sign that ammonia is present

Rule of Exposure

5 ppm

You can

smell

it

50 ppm

It can

harm

you

–

Long Term Exposure

300 ppm

IDLH

–

Immediate Danger to Life & Health

5,000 ppm

It can kill you

If you can smell ammonia outside of the furnace, move away from the area and alert necessary personnel in the lab

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Consequences of exposure (in ppm)

Airgas

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Ammonia exposure

Airgas

Exposure to liquid anhydrous ammonia or high concentrations of ammonia vapor cause:

Blindness

Dehydration of body tissue

Chemical burns

Frostbite

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Ammonia Characteristics

Airgas

Anhydrous = without water

Pungent, colorless gas

Stored as liquid under pressure

UN identification number is 1005 (on shipping documents and DOT Energy Response Guide

Pressure varies greatly with temperature

50 °F = 75 psig

90 °F = 165 psig

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Ammonia Characteristics

Airgas

Ammonia is sensitive to pressure and temperature

A small volume of liquid anhydrous ammonia produces a large volume of gas at atmospheric pressure

Ammonia has a limited flammability range

15-28% in air generally found only in confined space

Mixtures of oil and ammonia may reduce lower level to 8%

Ammonia has a

very strong affinity for water

1 gallon of water will absorb 1,300 gallons of ammonia vapor by volume.

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Ammonia Loves Water

Airgas

BAD

:

Ammonia attacks the moist areas of the body

The body is mostly water

The eye is 90% water

Exposure can result in immediate eye damage

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Ammonia Loves Water

Airgas

GOOD

:

Water can be used for first-aid treatment for NH

3

exposure

Water can be used to absorb an ammonia vapor release.

This is why the tubing exiting an ammoniation tube ends in a beaker of water.

Water should

never

be mixed with liquid ammonia. This will result in a violent reaction and vapor release.

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Water –

First Aid for AmmoniaLarge quantities of water (15 min. of continued flushing) are recommended for washing contaminated skin areas or for eye contact.Rule: For an eye exposed to ammonia, hold the eyelid open

and wash for 15 minutes with water

Airgas

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First Aid Treatment for Ammonia

Inhalation:Remove from exposureAdminister artificial respiration or oxygen if breathing has stopped.

Seek medical attention

Skin contact:

Immediately flush with large quantities of water and continue for 15 minutes. Do not remove clothing if frozen to skin

Seek medical aid.Airgas

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First Aid Treatment for Ammonia

Eye contact:Immediately flush with large quantities of water. Continue for 15 minutes.

Seek medical aid.Ingestion:

Do not induce vomiting. Give 1-2 glasses of milk or water

Seek medical

Airgas

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Personal Protective Equipment (PPE

) Requirements for AmmoniaAirgas

Full

facepiece

respirator is highly recommended during use, but it is at the very least

REQUIRED

to have annual training and possess this type of respirator.

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Skin Damage

Critical skin damage begins at 24.8 °F and becomes irreversible at -18.5 °FThe degree of tissue injury is proportional to the duration and

concentration of exposureAlkaline burns go

deeper

than acid burns

Alkali burns are yellow, soapy, and soft in texture. When burns are severe, skin turns black and leathery.Airgas

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What NOT to wear

NEVER wear contact lenses when working near ammoniaAmmonia may become trapped behind the contact lens, increasing the risk of damage to the eye and reducing the effectiveness of

the eyewash.

Airgas

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Chlorination

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Chlorine Synthesis

Primary usage in DNICDC synthesisMC(s) + 2Cl2(g)  MCl

4(g) + C(s)

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Chlorine properties

Boiling point: -34.04 °CCompressed tanks are liquid chlorineChlorine expands when

released during operationDensity: 3.2 g/L

More dense than air

Will flow towards the floor (heavy)

AppearanceLiquid: blue-amber (not likely to be seen)Gas: pale green-yellow

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Main hazards of chlorine

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Main reaction:

Cl2 + H2O ->

HCl or HClO

(water in air or on surface)

Corrosive to metals and living tissue

Primary afflicted organs: Lungs (inhalation)Symptoms: coughing, wheezing, shortness of breath, difficulty breathing, tightening in chest, pulmonary edema (fluid in lungs)) Long-term exposure: chronic asthma Skin- Symptoms: irritation, burning- Long-term exposure: tissue necrosis, scarring Eyes Symptoms: irritation, burning in eyes

Long-term exposure: permanent eye damage possible

Used as a chemical weapon in WWI,

Several subsequent conflicts

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Inhalation Hazards

Dangerous levels: 30 ppm: shortness of breath, chest pain, possible vomiting 40-60 ppm: lung irritati

on, accumulation of fluid in lungs

>50 ppm: loss of consciousness

> 100 ppm: lethal dose possible

Average lethal dose: 300-1000 ppm for 30 minutes

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Immediate Response

Smell detected at 1 ppm limitMove victim to fresh airCall EH&S Immediately! Give artificial respiration and CPR (

if trained) if there is no breathing or no pulse

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Additional Hazards

Chlorine is a strong oxidizer (like oxygen) but is not flammable Chlorine reacts violently with oil and grease Chlorine

corrodes sensors and electronics and damages lab equipment

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Standard Operation

1-25 ppm Full face respirator with cartridges (yellow) Standard PPE & rubber gloves

25-100 ppm Full self-contained breathing apparatus (only used by EH&S and emergency personnel)

All respirator users must undergo annual certification

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Compressed Cylinder Operation

Only certified users may use the chlorination setup Tank requires specialty regulator and valveValve is wrench-operated (not standard wheel)

Respirator protection must be worn for changing cylindersWasher between tank and regulator must be replaced when changing tanks

Back (tank) pressure is low (80 PSIG) due to compressed liquid state

•  Forward pressure cannot exceed 10 PSIG

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Filtration Flask Operation

Reaction uses excess Cl2:Chlorine must bubble into neutralizing media •  Flasks: 5M

NaOH (400grams/2 Liters)Content is

highly corrosive

•  Neutralization: Cl

2 bubbles should react/dissolve into solution prior to reaching surface •  Standard rules: 2-3 small furnace runs, 1-2 large furnace runs •  Content is hazardous wasteSodium hydroxideSodium chlorineSodium hypochlorite (bleach) *Metal Carbide* oxide

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Chlorine System Operation

 Flow rates– 1 bubble/second for small furnaces (F1, F2) – 2-4 bubbles/second for large furnace (LTF) Ensure system is sealed and leak-proof prior to operating chlorine

Purge system with Ar prior to any Cl

2

flow (ensures system integrity)

Purge system with Ar after chlorination for at least 3 hours prior to opening system

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Purging/Stabilizing Agents

H2 or NH3 ammonia gas Gases are reducing agents (may violently react with excess Cl

2 in system – purge system with

Ar

prior to use)

Must be stored in separate storage cabinet from oxidizing chlorine or other oxidizers

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Typical problem sources

Leaks in system Cracked glass, old fittings, improperly secured or tightened down fittings BlockagesMetal chlorides hydrolyze when they reach filtration flask, form solid products that block tubes

Chlorine gas escaping filtration flask Excessive flow rates

Expired

base solution