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2009 FAI Seminar

Safety in the Global Ammonia Industry

Venkat PattabathulaGlobal Ammonia Technology Manager

Incitec Pivot LtdBrisbane, Australia

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Incitec Pivot

• Largest fertiliser manufacturing and distributing company in

Australia

• Has largest explosive grade AN manufacturing base in North

America, operates as Dyno Nobel

• One of the key values of the company

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Phosphate Hill

• Major Manufacturing and Distribution Sites

Distribution Sites

Phosphate Hill/Mt Isa:MAP /DAP: 975 ktpa

Sulphuric Acid: 1Mtes

Cockle Creek:Superphosphate: 250ktpa

Kooragang Island:Bagging and Distribution

Geelong:Superphosphate: 450ktpa

Portland:Superphosphate: 250tpa

A network of coastal and inland distribution centres supports Incitec Pivot’s manufacturing facilities

Gibson Island:Urea: 280ktpa

Ammonia: 300 ktpa

Ammonium Sulphate: 200 ktpa

Mount Isa

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Incitec Pivot Australia

Powder River

Basin

Appalachian

Coal Basin

� North America is the largest explosives market in the world

� No.1 USA & Canada

By Product:

� 60% AN based explosives

� 23% Initiation systems products

� 9% boosters and dynamite,

� 5% packaged products

� 3% other

Dyno Nobel, North America

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AIChE Ammonia Safety Symposium

• American Institute of Chemical Engineers (AIChE) Ammonia

Safety Symposium became a main platform for worldwide

ammonia industry.

• Sharing of experience helped the industry and made plants

safer, reliable and efficient.

• Ammonia industry grown by about six folds in last 20 years

from about 30 to 190 Mt/year.

• Papers on various topics -

- Fires, Explosions, Ruptures and Other Incidents

- Plant Performance

- Plant Debottlenecks

- Process Technology Developments

- Maintenance & Metallurgical Improvements

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Industry Major Incidents

• 163 Listed in a table with year reported, incident, root cause

and remedy action taken.

• Incidents involved fatalities.

• Incidents that had major impact on business

- Reformer tube failures

- Waste heat boiler failures on front and backend

- Explosion of storage tanks and CO2 line

- Start up heater failures

- Fire and explosions in synthesis loop

- Synloop heat exchanger failures

- Ammonia converter failures

- Failure of ammonia storage tanks

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Failure of Ammonia Injector Pumps

• In 1989, high-pressure casing of ammonia injector pump in ICI’s Billingham, UK, urea plant failed catastrophically, killing two employees.

• Crankshaft fractured, plungers came out of cylinders, caused uncontrolled release of ammonia.

• Fatigue crack caused the crankshaft to fracture.

• Initial design of machine not ensured the plungers do not come out of cylinders on crankshaft failure.

• Better design would have improved ammonia containment.

• ICI developed extensive list of improvements, included

- design changes to injector pumps,

- modified emergency and normal operating procedures.

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Accident in a Lithuanian plant

• In 1990 Symposium, Bengt Orval Andersson reported on Lithuanian fertiliser plant accident happened in March 1989, destroyed a 10,000-tonne-ammonia storage tank.

• Whole ammonia tank slid from its foundation, smashed with great force through a surrounding wall of reinforced concrete, finally landed 40m from the foundation.

• Enormous devastation around the tank, 70cm deep liquid ammonia. Large quantities of ammonia evaporated, vapour caught fire and whole plant engulfed in flames.

• About 32,000 people evacuated from a nearby town, rescue operation continued for three days. Seven people died, 57 were injured.

• Ammonia tank over-pressured when its contents rolled over.

• Warm ammonia supplied to tank bottom, caused the rollover while tank refrigeration compressors out of service.

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Explosion of Ammonia Separator

• Hans Dieter Marsch (Uhde) reported in 1990 Symposium :

Ammonia separator in a 1000 tpd plant exploded into at

least 80 fragments.

• Multishell separator was in service for 10 years.

• Most likely cause: presence of mercury (Hg), affected steel

properties and formed explosive compounds.

• Lesson from this: If Hg detected in feed gas,

it should be removed to the lowest possible level.

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Explosion and Fire in Ammonia Synthesis Section

• In 1991, a loud explosion followed by a large fire damaged Ammonia Unit 2 of Krishak Bharati Cooperative Ltd (KRIBHCO), Hazira, India.

• Synloop exchangers exposed to flames and shells of exchangers overheated. Cold insulation of chillers and separators burnt off.

• Motorised actuators, many instruments and power cables damaged. Control room window panels and frames shattered.

• Causes of the incident: Popping of a relief valve in synloop caused an explosive mixture in vent header with ingress of air from a drain line on tail pipe as a valve left open after manual draining. Ignition caused by a spark from friction in the pipeline.

• Remedial actions: RV relocated with a new support; high pressure trip of syngas compressor; purging of cold vent header with N2; new water seals on drain lines and reduction of window panels in control room.

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WHB Failure after Debottlenecking Process Air Compressor

• In 1991, BASF ammonia plant No.3 in Ludwigshafen,

Germany had emergency shutdown from WHB boiler

failure.

• Sudden loss of water level in boiler from a ruptured tube.

•Several leaks and erosion noticed on boiler tubes.

• NH3 plant capacity increased with debottlenecking of

process air compressor, caused two-phase flow in boiler

tubes and eroded the tubes.

• Complete boiler was replaced in a 4-week shutdown

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Failure of two primary make gas boilers

• ICI Chemicals and Polymers Ltd, Billingham plant in

England reported tube failure of primary waste heat

boilers in 1993.

• The principal damage occurred as a consequence of

ferrule failures and subsequent loss of refractory.

• Total duration of inspection and repair including the

replacement of ferrules was 35 days, involved

approximately 4,000 man-hours.

• Lesson learned from this failure: prolonged operation

with serious tube leaks should be avoided.

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Explosion of H2 in CO2 Line

• On 13 April 1997, CO2 transfer line from ammonia

plant exploded at Hydro Agri Prosgrunn facilities in

Norway.

• No injuries, but 850 meters line totally destroyed and

glass windows on nearby buildings broken.

• H2 rich gas entered pipeline, line not purged

effectively with N2, explosive mixture formed with air

ingress, then ignited.

• Trip system modified and new separate sampling

lines installed for each to eliminate common mode

failure.

• A new analyser provided for reformer section start

up.

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Inner Basket Failure of Ammonia Booster Reactor

• In 1997, ABF Bintulu ammonia plant in Malaysia

experienced a major failure of inner basket of ammonia

booster reactor.

• Catalyst leaked, plugging downstream synthesis loop

high pressure equipment and piping.

• Missing bolts on catalyst basket and strips,

numerous trips coupled with defective valves caused

the incident.

• Basket was repaired and reinforced after unloading

the catalyst.

• Converter internals can be improved to increase its

robustness.

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Primary Reformer Failure

• Agrium Fort Saskatchewan Nitrogen Operations

experienced a massive reformer failure in

November 1998 during a re-start following a short

maintenance outage.

• Approximately half of the tubes completely failed,

tube failures occurred mainly at welds. No risers

failed, but overheating was evident.

• All reformer radiant tubes were replaced in 39

days. Russian-built cargo planes transported

tubes from the UK to Canada.

• Agrium installed automatic shutdown system to

protect from overheating during start-up and

modified operating procedures to reflect changes

in communication between shifts.

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Reformer tube failure

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Failure of inner shell of a double wall ammonia storage tank

• In 1999, a 5,000 tonne ammonia storage tank

decommissioned at Coromandel Fertilisers Ltd in India.

• Noticed ammonia liquid level in annulus area of the double

integrity tank, ammonia collected from splashing during ship

unloading at high levels.

• Level transmitter indication wrong, inner cup failed when

draining from a hydrostatic head of ammonia in annulus.

• Bottom plates fractured and circumferential welds

failed.Tank repaired, bottom plates renewed.

• Many improvements made on tank instrumentation: new TI

on annulus with a low temp alarm; interlock to trip ammonia

pumps if annulus level reaches 400mm level; separate level

indications for inner cup and annulus and up-to-date

documentation on ammonia tank.

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Explosion of MDEA Storage Tank

• In August 1999, an explosion in MDEA storage tank at Alaska Nitrogen Products’ (ANP) plant in Kenai, Alaska, propelled the tank off its base and into the air.

• Tank landed on an adjacent air-cooled heat exchanger, which was filled with synthesis gas.

• Impact of tank on air-cooled heat exchangers initiated a second explosion and fire. Three operators received minor injuries.

• Reverse-flow phenomena caused process gas to enter the storage tank, ignited by an unknown source.

• ANP installed check-valves in MDEA system, equipped storage tank with inert gas-blanketing system.

• Conducted PHA on MDEA system, revised operating procedures to improve operator awareness of reverse-flow and other start-up/shutdown conditions.

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MDEA Tank Explosion

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Converter Start-up Heater Failure

• In 2005, rupture of coil primarily caused by inadequate flow of syngas through the coil at Incitec Pivot Ltd

• Direct cause - short term overheating ruptured the coil, allowing high pressure syngas in to the fire box.

• H2 rich syngas contacted the naked flames from the burners and led to a fire/explosion.

• Root cause of the incident:

1. Installation of the force and bypassing of a critical

trip system.

2. Failure to remove the force/trip bypass prior to

starting up the main burners.

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Fire on Start Up Heater

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Fish mouth failure of cross over pipe

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Retubing of reformed gas boiler

• In 1993, Rashtriya Chemicals & Fertilisers Ltd (RCF)

ammonia plant in India reported 33 tubes leaked after 600

days in operation.

• Cracks behind tube to tubesheet weld joints on hot

compartment.

• Boiler low level experienced on few occasions.

• Accumulation of sludge and sediments noticed on

waterside despite continuous and intermittent boiler

blowdown.

• Half of the tubes collapsed within one meter of inlet

tubesheet.

• Complete In-situ retube took 34 days.

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Waste Heat Boiler Damage

• Incident happened in 1994 at Jianfeng Chemicals,

Fuling, Sichuan, PR China.

• Cause of failure - high pH of boiler water.

• In-situ repairs took 115 days, boiler achieved

design production rates after repair.

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Catastrophic Failure of WHB

• In 1994, Terra N2, Courtright plant in Ontario, Canada

experienced a boiler failure after 9 years in operation.

• Weld joints failed behind tube to tubesheet and

tubesheet to shell forging.

• Cause of failure: departure from nucleate boiling,

initiated by increase in plant rates.

• New boiler design incorporated - larger dia tubes in

front section, increased diameter of shell and a new riser

design.

• New section installed in 1996.

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Metal Dusting on Waste Heat Boilers

• In 1994 Symposium, DSM, The Netherlands reported

metal dusting on 3 plants in between secondary reformer

and HT shift converter.

• Modern plants operate at low S/C ratio and high

pressure, will increase CO, a potential for carbon

formation.

• Metal dusting process can be slowed or even halted by:

•the prevention of carbon formation,

•the prevention of carbon adsorption,

•the formation of a less stable intermediate carbide.

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Remedial Actions to WHB Failures

• Between 1988 and 1995, major failures

experienced on WHBs at two Asmidal plants in

Arzew, Algeria.

• Localised refractory failures and subsequent

overheating on boiler tubes.

• Partial repairs done on one plant and boiler

replaced on other ammonia plant.

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Replacement of Waste Heat Boiler

• Between 1990 and 1994, failures on WHBs at Fauzi

Fertiliser Co. Ltd in Pakistan resulted into a down

time of 91 days.

• Loss of boiler water level and subsequent heat up of

WHB with process steam flow through air coil caused

the failure.

• Observed tube holes, micro-cracks on tube to

tubesheet weld joints, ligaments and weld chips.

• A partial replacement of 101 tubes lasted for 9

months and finally WHB replaced.

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Benfield solution storage tank explosion

•In 2006, an explosion occurred in a Benfield

solution storage tank at Borealis Agrolinz’s

ammonia plant in Austria.

•During hot work to install an additional vent on the

tank, the roof blew off.

•Investigations and laboratory tests carried out in

association with the University of Erlangen

identified the root cause as the evolution of

hydrogen.

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Benfield solution storage tank

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Ammonia Storage Fatality

• In 2005, NH3 tank emptied out for a repair, at Yara facility in

Rostock, Germany.

• One person killed while recommissioning the tank and another

injured.

• 100 tonnes of ammonia released.

• Tank rupture from high pressure

Root Cause:

- Thin layer of oil prevented mixing of anhydrous ammonia with

aqueous ammonia which was used to cover tank bottom. When a

valve on tank outlet opened, caused violent reaction and raised

tank pressure causing rupture.

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Ammonia tank rupture

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Summary

• All accidents are preventable.

• In spite of 90 years of NH3 industry, there are still

challenges in process safety.

• AIChE NH3 Safety Committee call upon ammonia

producers, regulators, process licensors and

equipment suppliers to join hands in improving

safety, reliability and efficiency of the plants.

• We are in the noble cause of feeding billions of

people across the globe and let’s prevent all

incidents to save human lives, reduce injuries and

protect property.

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Acknowledgement

• Incitec Pivot Ltd (IPL)

• My co-authors: Don Timbres and Bhaskar Rani

• Our friend, Walter Benson for all his support

• All the authors, presenters who spent their valuable

time in writing and presenting papers over many

years.

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Thanks !!!

Any Questions please?