Fuel System Contaminants Organic/Inorganic- What

are they and where do they come from?

Howard Chesneau, PresidentFuel Quality Services, Inc

2

Is There A Problem

In Diesel?

You Bet!!

Newer Emissions-Regulated Engines

John Deere HPCR

10 Micron Primary Filter

2 Micron Final Filter

Tier 4 or EURO 5/6

These systems operate at 30,000+ PSI and require

cleaner fuel than ever before.

How Clean Is Your Fuel?

Generally, new fuel is delivered:

Meeting all current ASTM specifications

With an avg. cleanliness of ISO 22/21/18

In a word: dirty

ISO 4406 Cleanliness: 4µ, 6µ, 14µ vs. Clear &

Bright

100 µm

80

µm

40

µm

25

µm

10

µm

2 µm

Fuel at ISO 22/21/18

This fuel is considered “clear and bright”.It contains 2-4 million dirt particles >4 micron.

An Industry Problem

At required Tier 4 efficiency:

10 filters needed, 1 every 1,000 gallons

10,000 gallons of “typical” diesel contains 700 grams contaminant;

only 0.7 grams is allowed to meet Tier 4 cleanliness

Dirt present in “typical” 1000

gallon tank of diesel fuel

Dirt allowed in 1000 gallons

for Tier 4 Engines

.

90% of Diesel Troubles are due to dirt and water in the

fuel. (1931 Diesel Fuel System Care)…some things

never change!

Biological (aka:

Bugs, Humbugs)

What Are Microorganisms?

Active Microorganisms such as: BACTERIA FUNGUS (yeast & mold)

ALGAE is not included because requires photosynthesis

Microorganisms

Conidia - the “seeds”

FungiEukaryote

Bacteria Prokaryote

12

The Needs of A Microorganism Are Few and Simple

First and Foremost is

WATER!!!!

Factors Necessary For Microbial Growth

Microbial Growth

Aqueous Environment

Carbon Source

Terminal Electron Acceptor

Donor Electrons

EnergySource

Introduction

A century of investigations, decades

of research, and numerous peer

reviewed studies have conclusively

substantiated the causal links

between fuel, water, and

microorganisms that cause

Microbially Influenced Corrosion

(MIC).

MIC is responsible for both exterior

and interior corrosion to a variety of

fuel storage systems and potential

release of hydrocarbons.

MIC

Fuel

Water Microbes

15

Examples Contaminated Fuels

Gasoline Aviation Fuel

Biodiesel (B20)

Diesel

16

Carbon

Source

Terminal

Electron

Acceptors

Electron

Donor

Energy

Source

Aqueous

Source

Fuel Sample With Microbial Involvement

Fuel Water

Interface

Biosurfactant

water, inorganic

salts, & TEA

Aqueous Environment

1. Moisture and

microbial spores

enter refinery

storage tank via

ventilation

system.3. Warm refined fuel cools

condensing water and

microorganisms along the

distribution system,

2. Poor ballast stripping

can transfer water ballast

during offload

4. Pipelines and storage

tanks are contaminated

from upstream product

tenders,

External Sources of Contamination

◦ Ballasting of UST during installation

◦ Water contaminates USTs,

◦ PEI/RP100-2000

Installation of new UST:

External Sources of Contamination

Steel Tank Institute: “Keeping Water Out of Your Storage System,” March 2004

H20

contaminants into tank

Existing UST

Rising/falling ground water

r

W a te r

F u e l

W a te r

F u e l

F il l

F illP u m p

P u m pP u ll F r o m

H e r e & Y o u

D o n ’t G e t I t

P u ll F r o m

H e r e &

Y o u G e t I t

Beta Oxidation Pathway

Hydrorefined Fuel

Oxidation of the petroleum product makes the material more available for microbial metabolism

In its reduced form petroleum fuels are slow to microbial degradation

22

Hydrocarbon fragment for use or further oxidation

Acetate anion fragment

O -

O

n-Alkane

1° Alcohol

Aldehyde

CarboxylicAcid

OH[O2]

O[-2H]

[+H2O/-2H]

OH

O

ß Carbon Cleavage

Typical Degradation of

Jet Fuel and B20

23

Biodeterioration Pathway

FAME

Microbial Enzymatic attack of the terminal methyl group

Fatty Acid + free methyl group

CH3 ( -R)

O

O

CH3 ( -R)

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O

O

-

Acetate anion fragment

O

O

-Hydrocarbon fragment for use or further oxidation and fragmentation.

ß Carbon Cleavage

Comparison of Biodeterioration Rates

Biodiesel Metabolism EPA Standard 560/6-82-003,

CO2 Evolution (%)

Day

s

Rape

Ethyl

Ester

Rape

Methyl

Ester

Soy

Ethyl

Ester

Soy

Methyl

Ester

Neat

Rape

Neat

Soy

#2

Diesel

Dextro

se

0 0 0 0 0 0 0 0.00 0.00

7 69.01 66.32 67.68 68.4 58.39 60.57 13.20 59.84

14 79.15 80.72 78.40 77.83 70.47 70.12 21.04 80.19

28 86.92 88.49 86.40 85.54 78.45 75.95 26.24* 87.79

* Reduce mineralization rate due in part to the need to oxidize the reduced hydrocarbon to the fatty acid

Impact of Microbial Contamination

Degradation of the fuel

and fuel additives

Production of

biosurfactant

Production of low

molecular organic

acids as metabolites

Biomass and biofilm

production

Sludge formation

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Impact of Microbial Contamination

Microbially Influenced Corrosion

Flow line restrictions

Filter plugging

Engine wear

Corrosive deposits

Reduced heat of combustion

Fuel property changes

Loss of additive performance

27

28

T A N K W A L L

Examples of Pitting Corrosion

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Saddle Tank

Corrosion

Examples of ULSD Accelerated Corrosion

STP Reducer Fitting

32January 13, 2014

Examples of ULSD Accelerated Corrosion

Examples of ULSD Accelerated Corrosion

Detection and Enumeration of Microbial Activity

• Microbial organisms found in fuel systems

–Bacteria

–Fungal (mold & yeast)

–Not Algae (requires sunlight for photosynthesis)

• Enumeration

–Qualitative (yes or no)

–Semi-quantitative

–Quantitative

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Traditional Growth Techniques

Fuel sample is filtered on a sterile

disc and place on growth media.

Incubated for 4-8 days to express

results microbes as colonies

(cfu/L).

Good repeatability but longer

incubation times can produce

results not representative of

original sample.

Test complies with IP 385 and

ASTM D6974

36

Modified Growth Technique Dip Slides

• Inoculate dip slide with water

samples only

• Incubate for 4-8 days to express

colonies as cfu/mlH2O.

• Long incubation times can

produce results not

representative of original

sample.

• Fuel contamination of dip slide

will ruin test.

• Test is portable but results take

4-8 days

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Modified Growth Technique Liquid Tester

Inject the fuel / water sample

into bottle with growth media

and color indicator sensitive

to pH changes.

Incubate sample 30-72 hrs to

produce color change

express activity in log10

Acidity in fuels can produce

false positive results.

Test is portable but results

take 30-72 hours.

38

Dual Use Speed Gels

Introduce fuel or water sample into test container with nutrient gel.

Incubate sample 1-4 days to express microbes colonies (cfu/Lfuel or cfu/mlH20)

Good repeatability but longer incubation times can produce results not representative of original sample.

Test is portable but results take 1-4 days.

39

Specialty Gels

The Sig® Sulphide is a semi-quantitative test used to detect anaerobic microorganisms, such as sulfate reducing bacteria (SRB)

The test is performed by inoculating the selective gel and incubating the glass tube. The speed and extent of the gel turning black indicates the severity of SRB contamination

Can be performed in-house, and is semi-quantitative.

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Immunoassay

Tests for H. resinae, bacteria, and

other fungi.

The test is a lateral flow immunoassay

suitable for the field or lab.

The test is performed as directed

using fuel or water in 10 minutes.

The combination of lines indicates a

negligible, moderate, or high levels of

microbial growth. (See note right)

Practical if time results are time

sensitive. Test failed for H. resinae (bottom paddles) no control line.

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Bioluminescence

Fuel/water samples are

prepared and introduced to

test pen and measured within

5minutes.

One microbial ATP molecule

produces photon of light.

#Photons α microbial ATP α

proportional to the #microbes

in sample

Complies with ASTM D7463

House Keeping

One of the simplest ways to control

microbial contamination is by

housekeeping.

Microbial contamination enters a fuel

systems from three different ways:◦Air

◦Water!!!!!◦ Fuel

43

“Housekeeping” Problems

Air

Microbes are ubiquitous in the soil around the site

Spores can enter fixed roof tanks as dust through ventilation systems

Spores can also enter a floating roof tank as rain wash through failing seals

45

Water Microbes require

water to be viable,

Upstream systems

that use water or

have poor water

removal have the

potential to

propagate microbes

downstream.

Onsite facilities

46

Fuel

Microbes live in the water phase.

Microbes are pulled into the fuel layer inside suspended water droplets/hydrophilic particles.

The fuel and suspended water transfer the microbes downstream where they reside and multiply.

47

Housekeeping

Try to use air filters breathers to trap dust

and debris from entering the tank(s),

Sump fuel storage tanks regularly

and keep as dry as possible. Implement a surveillance program to monitor

the tank, fuel and/or water from microbial

contamination and deal with accordingly.

48

Examples of complete

filter systems (in-out,

and air filtration)

What is Bulk Filtration?

Production Refining

Product distribution

End Use

Bulk filtration is filtering fluids upstream

of the point of dispensing into the equipment

Why Bulk Filtration?

Components have become more

sophisticated; more sensitive to dirt

and water

Decrease initial wear in system

components due to the use of dirty

fluids

Reduce Total Cost of Ownership

Bulk filtration gets the fuel as close as

possible to the cleanliness requirements

of new diesel engines- prior to the fuel

being pumped into the equipment

Remediation

Considerations When Selecting a Biocide

Local, state, or country regulatory issues.

Anti-Microbial Type (Biocide, Biostat)

Method of Action (Kill Mechanism)

Product Solubility, Partitioning Capability

Dose Rate ◦ Lethal vs. sub-lethal

◦ Resistance vs., Tolerance

Frequency of Use

Response Time

Biocide Label

56January 13, 2014

Antibiotic vs. Biocide vs. Biostat

Antibiotic – a chemical agent that kills by targeting a

single very specific critical site in the organism.

Biocide - Is a chemical agent that kills microbes by

targeting multiple critical sites of the organism.

Biostat – Is a chemical agent that stops

microorganisms from reproducing, while not

necessarily harming them. Upon removal of the

agent, the microorganism usually start to grow

again.

Product Solubility & Partitioning

Types Description

Strict Water Soluble Only soluble in the water phase. Not capable

of addressing microbial contamination on

vertical and overhead surfaces and

overhead and downstream systems

Strict Fuel Soluble Only soluble in the fuel phase, typically

added with each batch of fuel. Product

requires 40CFR79 registration.

Universally Soluble Product that is primarily soluble in one

phase and partitions into another phase.

Biocide Types

Dose Consideration

Lethal dose – a dose rate of biocide sufficient to kill

or eliminate a microbial population by a minimum of

3-4 orders of magnitude.

Sub-Lethal dose - an insufficient dose rate of

biocide that results in population reduction of less

than 3 orders of magnitude

Resistance – The ability of the organism to lower its

susceptibility to the actions of a chemical agent

Tolerance – The ability of an organism to tolerant the

presence of a chemical agent.

Last resort:

Tank Cleaning

Don’t Wait for the Heart

attack to Lower Your

Cholesterol

WATER, WATER, WATER

KEEP IT OUT!!!!!!!!!

Conclusion Microbial contamination has various pathways. Even though the fuel is benign, aqueous phase

corrosion can occur in water bottoms that contain sludge, deposits along with microbial contamination.

MIC is corrosion that is influenced by the presence and activity of microorganisms.

Corrosion rates in storage tanks are accelerated at the liquid / fuel interface due to oxygen gradients and varies with depth.

Implement housekeeping for microbial control. Implement a surveillance program to detect and

remediate microbial contamination.

62

biological

biocide

water

fuel

testing

remediationcorrosionMIC

Questions?