This document summarizes research conducted by Chevron to evaluate detergents for cleaning oil refinery equipment. Several criteria were tested, including cleaning ability, foam production, emulsion formation, impact on oil and grease levels, and toxicity to microbes in wastewater treatment. A variety of commercial detergents were tested. The results showed significant differences between detergents in cleaning effectiveness and environmental impact. The best detergents for refinery use were found to be terpene-based cleaners that demonstrated high cleaning ability with low foam, emulsion, oil/grease levels, and toxicity. The study provides a framework for refineries to evaluate detergents based on key criteria.

1. Paper No.
00446
CORROSION 2000
R E F I N E R Y C H E M I C A L CLEANING:
C R I T E R I A FOR DETERGENT S E L E C T I O N
Chris Spurrell
Chevron Products Company
324 W. El Segundo Blvd.
El Segundo, CA 90245
Mialeeka Bibbs
Chevron Products Company
324 W. El Segundo Blvd.
El Segundo, CA 90245
Abstract
Mechanical equipment in the oil processing industry can operate for years between shutdowns. During
this time there is often a tendency for scale, debris and sludges to form within this equipment. During
the shutdowns these fouling materials have to be removed before mechanical work or even entry can be
allowed. Detergents have been developed to speed the cleaning and decontamination of equipment.
These detergents alone or in combination with other chemicals such as oxidizing agents have reduced
the need for caustic and acid washing of refinery equipment. Detergents, however, can interfere with the
subsequent reprocessing of the oil removed. And they may have adverse effects on the refinery's water
effluent system. Several criteria for detergent selection and field test methods are presented.
Introduction
Oil processing equipment has long been known to accumulate fouling materials while in operation.
These can range from polymeric sludges, sometimes called coke, to various corrosion derived materials,
such as iron sulfide, and scale forming mineral deposits formed from calcium, magnesium, barium, and
silica among others. There are also components of the crude such as benzene which can permeate the
equipment and must be removed to meet OSHA requirements. And, of course, flammability must be
reduced.
For many years the techniques of caustic washing and acid washing have addressed many of these
concerns. However, the generation of hazardous wastes from high or low pH washes has prompted the
development of detergent cleaners which can remove or mitigate many of the expected foulants without
generating hazardous or "listed" wastes. Further, a careful selection of detergent qualities can provide the
Copyright
@2000 by NACE International.Requests for permission to publish this manuscript in any form, in part or in whole must be in writing to NACE
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2. best cleaning during turnarounds while minimizing troublesome reprocessing of the recovered oil and
water solutions.
Many detergent formulations have been offered to the petroleum processing industry as
"environmentally friendly heavy duty degreasers." While noble in word and goal, these terms are hardly
quantifiable. Fairly objective measurements like the Hydrophilic / Lipophilic Balance fail to answer the
necessary questions of cleaning ability and subsequent processing impacts.
In order to arrive at a detergent selection criteria the Chevron E1 Segundo refinery embarked on a series
of tests, mostly field expedients, in order to provide a rational basis for selecting a cleaner to use during
shutdowns.
The main concerns of widespread use of detergent / surfactant materials around the refinery were:
1) How well does it clean?
2) How much emulsion will it form in the effluent system?
3) In contact with other hydrocarbon streams, how much oil and grease will the detergent put into the
effluent water?
4) How toxic is the detergent to the microbes in the effluent system's activated sludge plant?
5) How much foam will be generated in the drains and effluent system, especially in the Induced Air
Flotation (IAF) systems?
SOAPS TESTED
JAYNE PRODUCT: JPX, Energy Plus Red, Energy
W. R. GRAINGER: Ball-o-Solv, Knockdown, Red Eye, Jump Start, Gobble
CHEMCO: Citrifresh, Synthene, APC
DIANA INDUSTRIES: HS-1000, EP680AC, Citrus EP680AC
WEST PENETONE: Citrikleen HD-CH
UNITED LABORATORIES: Zyme flow
RAMCO: Pac Attack
PROCTOR & GAMBLE: Joy
DOW: Fantastik
CHEMISOLVE: US 1600
CA RECYCLING CENTER: D - 99
HARVEY UNIVERSAL INC.: Harvey's Power Grease & Tar Cutter

3. We chose these detergents to represent a broad spectrum. While we never investigated the active
materials in these cleaners, their advertising and characteristics indicated that we had examples of citrus
or terpene based cleaners, enzyme-based cleaners as well as commercially available household cleaning
formulations.
CLEANING ABILITY TEST
In order to rank the various soaps cleaning ability we coated thin carbon steel strips (corrosion coupons)
with residuum (from SJV crude) and then exposed the treated strips to a 160 Deg. F stirred water
solution which contained 10% of the various soaps. The residuum percent removal (by weight) was then
recorded. Only the terpene based cleaners were effective under these conditions (See Figure 1). These
cleaners were then tested at 5% and 1%. Only Q and C retained their effectiveness at 5% (See Figure 2).
None of the cleaners in this test were effective at 1%.
EFFLUENT IMPACT TESTS
In order to evaluate the impact on Refinery effluent systems and potential environmental impact we
measured the soaps foaming tendency, emulsion forming tendency, Oil and Grease contribution in the
presence of hydrocarbon, and toxicity towards Refinery activated sludge bio organisms.
FOAM TEST
For a foam test a 100 mLs graduated cylinder was filled with 90 mLs of tap water, 2 mLs of diesel fuel,
and 0.9 mL of soap. The cylinder with the solution was stoppered and shaken vigorously ten times. The
solution was allowed to settle for 10 minutes before measurements were taken. Foam ranged from 0 to
35 mL (See Figure 3).
EMULSION TEST
For an emulsion test the emulsion thickness was measured after the above-mentioned test. The chemical
cleaners exhibited emulsion ranges from 2 to 3 mL (See Figure 4). The majority of cleaners had an
emulsion band of 2 mL, which was equal to the blank, and the initial amount of diesel used.
OIL & GREASE TEST
After the above visual measurements were taken we transferred the test solutions to a 4 oz sample bottle
which was left undisturbed for one hour. A one mL sample was taken from the middle of the bottle and
tested for Oil and Grease content. The test used consisted of a Freon extraction followed by an infrared
absorbance using the Foxboro Oil and Grease analyzer. The test displayed Oil and Grease values ranging
from 1000 to 6000 PPM (See Figure 5).
TOXICITY TEST
The toxicity test used was developed at the E1 Segundo Refinery to test the toxicity of Refinery
chemicals towards their activated sludge. This test is not believed, or intended, to correlate with
traditional effluent toxicity tests which are performed on higher organisms (e.g.. Daphnia, Rainbow
Trout, etc.) Rather, this test is designed to use Refinery acclimated bio organisms in order to evaluate a
given chemical's potential to cause an Effluent Treatment Plant upset.
The toxicity test is based on respirometry wherein a bioculture is sealed in a flask along with nutrients,
test chemical, and an oxidation / reduction potential indicator. The Redox indicator changes color (blue
to pink to clear) with the microorganisms' consumption of the oxygen. The test flask oxygen uptake is

4. then compared to that of a blank. Toxicity or inhibition is measured by the additional time taken by the
organisms to consume oxygen compared to the blank.
We used two different concentrations 1,000 PPM and 10,000 PPM for the chemical dosage.
The toxicity test was based on a scale of 0 to 6 with zero being best (See Figure 6).
pH
The pH of 1.0-% soap solutions is shown in Figure 7.
E V A L U A T I O N SCOPE LIMITATIONS
In this study, while we performed tests on a variety of cleaners, we focused only on those cleaners,
which can truly function as "heavy duty degreasers." As a result there is environmental impact
information but no cleaning performance information on products, which may be effective as general
purpose cleaning agents. Another aspect, which was not addressed, was the ability of the cleaners to
reduce LEL and benzene. We have field experience here going back several years that the terpene based
cleaners are effective at removing benzene when added during a steam out or water wash. Likewise
other cleaners have been shown to remove benzene even though their effectiveness on heavy oils is poor
by comparison.
CONCLUSION
We were able to find quantifiable differences in the cleaners tested. These differences, which relate to
both the cleaning effectiveness and environmental impact, can be used to select the best detergent for
and oil processing facility's needs. Because of the differences in foulants, effluent treatment facilities,
disposal and reprocessing options, these tests are best viewed as a point of reference from which an
intelligent detergent selection can be made.

5. eL E A N I N G AB IL IT Y
3.5 Raling
3- Abo,,e 95% at 5
3 2 - 60-95% effective ~ 5%
1 - 20% or less effedrNeat 5%
2.5
0 - Little effed ci 10%
C 2
i i m
1.5
1
0.5
0
Q C J K O R A P H D E F M B G L N I U V S T
DE T E R GE NT
FIGURE 1 - Cleaning Ability
T op 5 Chemi cal el eaner s
120%
100%
80%
m
O
60%
40%
20%
0% m O K J Q C
DE T E R GE NT
FIGURE 2 - Top Cleaners

6. AVE RAGE FOAM
35
30
A
,,,,,4 25
v
E 20
E 15
0 1o
I.I.
0 ~- ~ Z CL ~ ~ ~ 0 --
DE T E R GE NT
FIGURE 3 - Average Foam
AVE R AGE E MU LS ION
3.5<
3
2,5
v
2
1,5
21
0.5
0
Z
Z
DET E RGE NT
FIGURE 4 - Average Emulsion

7. AVE RAGE OIL AND GR E AS E
7ooo T
6OOO
ASO00
1~ 4000
v 3000
m
2OOO
1000
Z
DE T E R GE NT
F I G U R E 5 - A v e r a g e Oil a n d G r e a s e
T oxi ci ty T es t
0 = Best
6.00 6 = Worst
5.00
4,00
I1•
,.~ 3.00
| m
O
iniB
2.00
X
0
I~ 1,00
0.00
R E B I A F P D N L G C O H Q M J K
DE T E R GE NT
FIGURE 6 - Toxicity Test

8. pH
11.5
11
10.5
10
~j: 9.5
Q.., 9
8.5
8
7.5
7
S M H V J Q T D C B O I N L A P R K F G E
DE T E R GE NT
FIGURE 7 - pH