NACE Refinery Chemical Cleaning Study


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Results from Summer Internship at Chevron Summer 1994.

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NACE Refinery Chemical Cleaning Study

  1. 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 AbstractMechanical equipment in the oil processing industry can operate for years between shutdowns. Duringthis time there is often a tendency for scale, debris and sludges to form within this equipment. Duringthe shutdowns these fouling materials have to be removed before mechanical work or even entry can beallowed. 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 reducedthe need for caustic and acid washing of refinery equipment. Detergents, however, can interfere with thesubsequent reprocessing of the oil removed. And they may have adverse effects on the refinerys watereffluent system. Several criteria for detergent selection and field test methods are presented. IntroductionOil 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, andsilica among others. There are also components of the crude such as benzene which can permeate theequipment and must be removed to meet OSHA requirements. And, of course, flammability must bereduced.For many years the techniques of caustic washing and acid washing have addressed many of theseconcerns. However, the generation of hazardous wastes from high or low pH washes has prompted thedevelopment of detergent cleaners which can remove or mitigate many of the expected foulants withoutgenerating 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 NACEInternational, Conferences Division, P.O. Box 218340, Houston, Texas 77218-8340. The material presented and the views expressed in thispaper are solely those of the author(s) and are not necessarily endorsed by the Association. Printed in U.S.A.
  2. 2. best cleaning during turnarounds while minimizing troublesome reprocessing of the recovered oil andwater 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 hardlyquantifiable. Fairly objective measurements like the Hydrophilic / Lipophilic Balance fail to answer thenecessary 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 seriesof tests, mostly field expedients, in order to provide a rational basis for selecting a cleaner to use duringshutdowns.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 systems 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.: Harveys Power Grease & Tar Cutter
  3. 3. We chose these detergents to represent a broad spectrum. While we never investigated the activematerials in these cleaners, their advertising and characteristics indicated that we had examples of citrusor terpene based cleaners, enzyme-based cleaners as well as commercially available household cleaningformulations.CLEANING ABILITY TESTIn 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 watersolution which contained 10% of the various soaps. The residuum percent removal (by weight) was thenrecorded. Only the terpene based cleaners were effective under these conditions (See Figure 1). Thesecleaners 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 TESTSIn order to evaluate the impact on Refinery effluent systems and potential environmental impact wemeasured the soaps foaming tendency, emulsion forming tendency, Oil and Grease contribution in thepresence of hydrocarbon, and toxicity towards Refinery activated sludge bio organisms.FOAM TESTFor 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. Thesolution was allowed to settle for 10 minutes before measurements were taken. Foam ranged from 0 to35 mL (See Figure 3).EMULSION TESTFor an emulsion test the emulsion thickness was measured after the above-mentioned test. The chemicalcleaners exhibited emulsion ranges from 2 to 3 mL (See Figure 4). The majority of cleaners had anemulsion band of 2 mL, which was equal to the blank, and the initial amount of diesel used.OIL & GREASE TESTAfter the above visual measurements were taken we transferred the test solutions to a 4 oz sample bottlewhich was left undisturbed for one hour. A one mL sample was taken from the middle of the bottle andtested for Oil and Grease content. The test used consisted of a Freon extraction followed by an infraredabsorbance using the Foxboro Oil and Grease analyzer. The test displayed Oil and Grease values rangingfrom 1000 to 6000 PPM (See Figure 5).TOXICITY TESTThe toxicity test used was developed at the E1 Segundo Refinery to test the toxicity of Refinerychemicals towards their activated sludge. This test is not believed, or intended, to correlate withtraditional effluent toxicity tests which are performed on higher organisms (e.g.. Daphnia, RainbowTrout, etc.) Rather, this test is designed to use Refinery acclimated bio organisms in order to evaluate agiven chemicals 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 (blueto pink to clear) with the microorganisms consumption of the oxygen. The test flask oxygen uptake is
  4. 4. then compared to that of a blank. Toxicity or inhibition is measured by the additional time taken by theorganisms 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).pHThe pH of 1.0-% soap solutions is shown in Figure 7.E V A L U A T I O N SCOPE LIMITATIONSIn 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 impactinformation but no cleaning performance information on products, which may be effective as generalpurpose cleaning agents. Another aspect, which was not addressed, was the ability of the cleaners toreduce LEL and benzene. We have field experience here going back several years that the terpene basedcleaners are effective at removing benzene when added during a steam out or water wash. Likewiseother cleaners have been shown to remove benzene even though their effectiveness on heavy oils is poorby comparison.CONCLUSIONWe were able to find quantifiable differences in the cleaners tested. These differences, which relate toboth the cleaning effectiveness and environmental impact, can be used to select the best detergent forand oil processing facilitys 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 anintelligent detergent selection can be made.
  5. 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 2i 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. 6. AVE RAGE FOAM 35 30A,,,,,4 25v E 20 E 15 0 1oI.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 2,5v 2 1,5 21 0.5 0 Z Z DET E RGE NT FIGURE 4 - Average Emulsion
  7. 7. AVE RAGE OIL AND GR E AS E 7ooo T 6OOOASO001~ 4000v 3000m 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. 8. pH 11.5 11 10.5 10~j: 9.5Q.., 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