Chevron Fire 1

8/12/2019 Chevron Fire 1

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November 2013 Lessons to be Learnt

John Evans, g3baxi Partnership

The Chevron Richmond Refinery Fire,

Aug 6th2012


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A PrefaceTrevor Kletz (19222013)

The best way to reduce risk is to avoid the hazard.

What you dont have cant leak. Trevor was instrumental in instituting the HAZOP

concept (50 years old this year)

He also was among the first to propose techniques

such as High Integrity Protection systems as

alternatives to relief valves

He was a proponent of the primacy of inherent

safety over protection systems

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Chevron statement regarding CSB Video

We also note that the CSB has released an animation with respect to

the events of August 6, 2012. After we previewed the animation, westrongly urged the CSB not to release it. We informed the CSB that the

animation contains numerous, material factual inaccuracies, the impact

of which is to oversimplify, and in some instances trivialize, decisions that

were made on that day. The animation also focuses on the actions of

specific individuals, which we believe has the effect, surely not intended,

of demeaning the challenges faced by the responding personnel. The

reasons behind the incident are far more complex than depicted in the

animation and we are disappointed with the CSB's decision to go forward

with this unfair depiction.

One must have some sympathy with this view, above all to recognise

that one learns from accidents in the full awareness that emergency

decisions are never made with complete knowledge.

At key points in the animation we should put ourselves in the position of

the individuals and ask what we would have done.

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Chevron Richmond - the Incident

Failure of a side cut in the Crude Distillation Unit (CDU)

Ignition of a vapour cloud Caused by corrosion

Consequences,

CDU out of action for months (may still be in this state)

Major damage to unit

Fortunate that no one was killed

15,000 people sought medical attention with breathing complaints

CSB investigation

State of California Investigation

Planned refinery expansion on hold

This presentation takes a lot of information from the CSB interim report,

some of the conclusions and analysis may be disputed.

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Chevron Investigation

Measurements in 2002 indicating thinning were not documented

properly to guide future inspections Information from industry experts concerning the processes leading to

failure and means of guarding against such failures, including component

by component inspections, was not shared effectively

2011 inspections during major maintenance did not include all

components vulnerable to sufidation corrosion After discovery of leaking pipe, the response teams did not recognise the

risk of rupture and fire.

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CSB Investigation

Currently at Interim Report stage Concludes the cause of the release was due to sulfidation corrosion

Identifies weaknesses in:

Inspection

Hazard assessment

Application of the inherently safe principle

Weaknesses in Management of Change

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Results from the Metallurgical Investigation

Anamet, Feb 11 2013, found:-

The 8 4-sidecut was schedule 40 carbon steel from the 1970s. 8 samples of 8 line taken, 5 samples from 12 including samples from

12 pipe replaced in 2011.

Nominal thickness 8 line 0.322 in, of 12 line 0.4 in

Sulfidation corrosion (leading to iron sulphide, FeS)

Wall thinning correlates to low silicon content (


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Rates of Corrosion with Silicon Content

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Susceptibility of US Refineries to Sulfidation

In the mid 1980s, pipe manufacturers began to simultaneously complywith all three manufacturing specifications (ASTM A53B, ASTM A106, and

API 5L) when manufacturing carbon steel piping. The majority of carbon

steel piping purchased following this time period likely has a minimum of

0.10 wt. % silicon content.

Over 95 percent of the 144 refineries in operation in the U.S., includingthe Chevron Richmond Refinery were built before 1985

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Inspection Techniques

One must inspect low silicon steel (in fact all steel, but Low Si in

particular) Inspection generally is done on elbows and fittingswhich are usually

the bits of the low Si pipework made of higher Si steel

There were no condition monitoring locations on the section of pipework

that failed

Even where accelerated corrosion was identified, on the 52 line in 2002,this was not followed up

(will PMI pick up low Si?)

And yet..

Chevron employees have authored industry papers on sulfidation

corrosion and had significant influence in the development of the

industry sulfidation corrosion recommended practice, API RP 939-C. This

recommended practice, first published in 2009, was developed under

Chevron leadership. So the expertise is in house.

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Corrosion Rate Influences

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http://www.ogj.com/articles/print/vol-110/issue-10/transportation/accurate-

corrosion-modeling-improves.html

Corrosion rates may be quite

complex As pipe wall loses thickness it may

flex more, promoting crack growth

and further corrosion

Change in composition will alter

corrosion rate Change in process P/T conditions


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Move to Processing Sourer Crudes

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From the CSB report


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Management of Change

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Source: CSB interim report

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Pinhole Corrosion?

Corrosion is characterised by pinhole

pitting Sulfidation corrosion has caused

severe fires and fatalities in the refining

industry, primarily because it causes

corrosion over a relatively large area, so

failures tend to involve ruptures or large

leaks rather than pinhole leaks. It can be

insidious in that moderately high

corrosion rates can go undetected for

years before failure. Finally, process

changes that increase the temperature

or sulfur content can creep up over timeand multiply corrosion rates so that

what was thought to be a low corrosion

rate system becomes corrosive enough

to fail before the increased corrosion

rate is recognized.

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Chevrons measurements on the

pipework around the crude unit

indicated an increased rate of

corrosion with a change to higher

sulphur crudes

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Consequences of Release

The release from the full bore rupture of the pipe was a cloud that

partially vapourised;

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Consequences of Release

Why would a diesel type fuel, not collect as a pool?

Distillation unit reflux lines will always have their process fluids attheir boiling points

These fluids are also at pressure and at height, so have potential

energy

They may have other dissolved components in them

Note also: as their vapour pressure is high (they are boiling) they willbe above their flash point

The natural state of this liquid on release will be a mist

Long chain hydrocarbons have higher flame speeds and are more

prone to deflagration and detonation (diesel engines dont need spark

plugs)

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Human Impact18

B

A

C

15,000 health complaints is probably

one of the highest from an industrial

accident, especially a non-lethal one,

but..

which refinery is

Chevron Richmond?

(the red line represents a distance of

1 km)(images courtesy Google Earth)

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Other Refinery Fires Caused by Sulfidation

The Chevron refinery fire is not the first to be attributed to sulfidation as a

cause. There are also:-

1988 - Chevron El Paso

1988 & 1993Chevron Pascagoula

2002Chevron Salt Lake City

2007Chevron Richmond (shelter in place alert)

2009Silver Eagle Woods Cross, Utah (damaging 100 homes)

2011Regina Canada

2012bp unit in Cherry Point, Washington

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The State of Refineries in the US

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US Industrial Process Safety Regulation Issues

West, Texas

Lack of knowledge and oversight of AN safety AN stored on pallets

No deluge systems

Plant siting a cause of the high fatality rate

Kleen Energy Connecticut

Gas blows in buildings?

Inability of the authorities to enforce common sense safety practices

Gas blows are still legal, though they are banned in Connecticut

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What is a Gas Blow

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The State of Refineries in Europe

KPMG report 2012

Over supply Competition from newer refineries

As it was a market report it did not mention high sulphur fuels or the age

of plant.

Margins are lower even with FCC to monetise low value feeds

Refineries are only an accident away from being a tank farm

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EU Refineries on the Edge

Grangemouth

Petroplus: inc. Reichstett and Coryton, both now tank farms ConocoPhilips Wilhelmshaven (tank farm)

EU refineries might be one industrial dispute, or fire, away from a change

of use.

Such events can have local political impact

They can also affect the economics of downstream industrial enterprises

such as petrochemical plants

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Conclusions

This fire was caused by a problem that can affect every refinery over a

certain age

It is hard to detect using standard techniques, even by industry leaders

Response to early indications and replacement is the only cure

Sensitivity to corrosion stressing mechanisms should feature in

inspection programs

It is difficult to distinguish between minor and major consequencescaused by corrosion leaks.

Precautionary shutdowns may be needed (though transients can also

cause problems)

Consequences may be vastly different to those that the refinery plans for

and fire fighting equipment may be lost Aged refineries are a world wide problem, operators need to be aware of

their heritage, and regulators need to be aware, too.

Some argument to say they are better regulated outside the US

(remember it is the same multinationals who operate them)

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Chevron Fire 1