Environment

Presentation to CBE 497 By

R.A. Hawrelak12 Feb, 2002

Outline

• EH&S Department at Dow in Sarnia.

• 1969 MOE Charges Dow with 100+ Violations – PO Plant Example.

• pH Control Problem and Solution.

• Mixing for pH Control.

• API Storage Tank Venting Problem.

• Recent Nova Benzene Spill.

Environmental, Health & Safety

• Environmental Control Mgr (PEng)• 3 Process Engineers (PEng)• 3 Technicians (Fish Pond + Field sampling)• 1 Industrial Hygienist (BSc.)

• Health Manager (Dr.)• 3 Nurses

• Safety and Loss Prevention Mgr (PEng)• 3 Process Engineers (PEng)• Emergency Response Co-ord (PEng) + Selected Group• Fire and Security Department• Transport. Emerg. (Plant Foreman + Selected Operators)

1969 Dow Blue Book• MOE Charged Dow with over 100 violations in

20 Chemical Plants• Greatest Problems found in the Old PO Plant.

• White Streak CaCO3 in the St Clair River.• CaCO3 Land Fill problem.• PDC, DCIPE discharge to St Clair River.• pH problem in hyrdrolyzer effluent.• Cl2 discharge to atmosphere.• C3H6 and C3H8 discharge to atmosphere.• Explosions in Degasser.

New Propylene Oxide Process

PO Reactions

• Cl2 + C3H6 + H2O > PCH + HCl• PCH + HCl > PDC + H2O (Waste)• PDC + Cl2 > DCIPE + HCl (Waste)• PCH + NaOH > PO + NaCl + H2O• HCl + NaOH > NaCl + H2O (pH Prob)

• PDC, DCIPE, NaCl, H20, NaOH &/or HCl to Special BIOX Plant

pH Control on the Internet

Have you checked these web sites out?

http://www.omega.com/techref/phtour.html

This one compares a poor installation with a better one. Note the two tank option.

http://csd.newcastle.edu.au/control/simulations/ph_sim.html

This one gives a simulation of different pH control schemes. It seems to favourthe three tank system (Part 4) that I used in some applications at Dow.

This is Poor pH Control

pH12 to 2 Is A Control Problem

Multiple Tank Solution

Good pH Control

• Small tank control to pH 9.6

• 2nd tank 20 times larger than first tank and controls pH to 8.3.

• 3rd tank is 20 times larger again and controls pH to 7.0

• Very costly and takes lots of operator attention.

• Check real time pH control on Internet.

Mixing for pH Control

• RAH CD File on Mixing.

• Sizing of Tank and Agitator

• Blending Example 1.

• pH Control example 2.

• Draft Tube for agitator free mixing.

API Storage Tank Venting

• Venting problem during Pump In.• Venting problem as temperature rises during the

day.• Benzene classified as a carcinogen.• MOE regulation went from 3 ppmv at company

fence line to 1 ppmv at point of impingement.• Initially Eng’g showed 674,000 lbs lost/yr.• BLOSS Finally showed 122,000 lbs lost/yr.• Installed new , stronger tank & burned vents.

Loading Logistics

From Boat Shell Essolb/hr 575,000 140,000 165,000No per Yr 4.0 3.0 24.0Duration, hrs 20.87 35.71 15.15USGPM 1,308.5 318.6 375.5MM lbs/batch 12.00 5.00 2.50

Maximumm USGPM Transfer to Tank No. 4 100Normal USGPM Transfer to Tank No. 4 40

Average Daily Temperatures

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Basis: J .R. Beckmann Ind. Eng. Chem. Process Dev. 20, 646-651

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Max Liq Sum

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Tank Levels

Fig 3: Minimum Inventory in D-14401, Yearly Level Profile

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Max Liq Lev = 27.2 ft.Avg Liq Lev = 15.6 ft.Min Liq Lev = 2.0 ft.

Yearly Benzene Breathing Loss = 122,020 lbs

J uly J ulyMaySep Nov J an Mar

Nova Benzene Spill• Dec 16, 2000, 8:45 AM detected odour.• 1 inch line split spilling benzene, toluene and

xylene – leak found and corrected.• 6 inch line split goes undetected for 12 hours

spilling 1,000,000 litres of benzene (30%) and toluene (70%).

• Dow operator notifies Nova of Spill.• Spill detected and stopped.• Line failure due to water hammer or failure to

turn off line steam tracing on blocked flow (liq expansion).

Nova Benzene Spill cont’d

• No emergency response warnings given to Corunna and Froomfield residents.

• Over 100 residence received high dose of benzene.

• 10 operators exposed to extremely high benzene exposure (2% by vol).

• Leukemia now known to be “Triggered” by high benzene exposure in rats. In past ten years, 3 operators have died with leukemia.

Nova Conducts Studies

• Nova cannot determine evaporation rates.• RAH asked for help.• 1,000,000 litres.• 6 inch depth.• 164 ft. by 427 ft.• 3.3 mph wind.• 19,533 lb/hr evaporation rate.• 98 hours to evaporate.• Did not apply foam till after 2 days.

Recent Spills In Sarnia

• Nova could be facing $2MM in fine after being charged for Dec 16, 2000 spill.

• $2MM charge to Shell for Mar 8, 2000 spill.

• $1MM charge to Ceda-Reactor,a contractor at Shell.

• $0.32MM charge to Dow on March 22, 2000 for latex plant spill.

• Sarnia CAER head replaced.

End of Presentation.

• Good luck on applying environmental aspects to your final report.