PC 32. Diesel Fuel Lubricity Improver

Transcription

1 PC 32 Diesel Fuel Lubricity Improver

2 PC 32 Diesel Fuel Lubricity Improver

3 INTRODUCTION CONTEXT The continuous worldwide tendency to increase engine performance and reduce emissions has necessitated the development of new generations of diesel Fuel Injection Equipment (FIE) and diesel fuels such as the Ultra Low Sulfur Diesel fuels (ULSD). The hydro-processing introduced to remove sulfur from those fuels also reduces the content of aromatics and destroys surface active compounds. Removal of those beneficial compounds affects lubricity and must be compensated for. In this context, Total Additifs & Carburants Spéciaux developed and patented in 1996 its best-selling lubricity improver: the PC 32. PC 32 is part of the Mono-Acid Lubricity Improvers (LI) that have been used worldwide by most industries for more than 20 years. 30% Ester-type 70% Mono-Acid type Global Lubricity Improvers Market Estimations from Total July WHAT IS LUBRICITY AND HOW IS IT MEASURED? Fuel Lubricity can be defined as the ability of a fuel to prevent or minimize wear in diesel Fuel Injection Equipment (FIE) that relies on the fuel to provide for lubrication. A large number of tests have been developed in order to simulate the problems observed in a real injection pump. Two tests have emerged: the High Frequency Reciprocating Rig test (HFRR) and the Scuffing Load Ball On Cylinder Lubricity Evaluator test (SL- BOCLE). To date the HFRR test is the only one to be recognized by professionals: ASTM mandates the use of HFRR to measure diesel fuel lubricity with a maximum limit of 520 μm (ASTM D6079). ISO has adopted the HFRR as the reference method and has specified lubricity as 460 μm maximum (ISO ). SAE recommends the HFRR below 460 μm (by ASTM D6079). FIE manufacturers stated in their joint Statement 1 that: It is essential that the lubricity of the fuel as measured by the HFRR test specified in ISO meet the requirement of a wear scar diameter no greater than 460 μm [ ]. Fuel with a lubricity exceeding 460 μm can adversely affect the lifetime of some fuel lubricated injection system components. The Worldwide Fuel Charter recommends the use of the HFRR, with a 400 μm maximum limit. I 3

4 THE STANDARD HFRR TEST In the HFRR test, a small sample of the test fuel is placed in a temperature controlled bath, so that the contact between a steel ball and flat steel disc is immersed in fuel. Temperature is set to 60 C and humidity is controlled and noted. The ball is then slightly loaded (2N) and moved back and forward (reciprocatingly) over the disc at a set frequency. The friction coefficient, fuel temperature and electrical contact resistance are monitored throughout the test. After 75 minutes, the wear scar diameter on the ball is measured both parallel and perpendicular to the sliding direction, and the mean wear scar measurement is taken. HFRR Test Test ball Test fuel Test plate Wear scare using ULSD Wear scare using ULSD + PC 32 x5 x5 x10 x5 MWSD = 593 μm 100 μm 100 μm MWSD = 289 μm I 4

5 PC 32 CHARACTERISTICS CONTEXT PC 32 has been used for the treatment of low sulfur diesel fuel since It is a cost-effective solution that improves the lubricity of diesel fuels and therefore prevents premature wear of FIE. PC 32 is a solvent-free blend of mono-carboxylic aliphatic and polycyclic compounds (Tall Oil Fatty Acid). It is specially designed for lubricity improvement of a wide range of diesel fuels corresponding to different crude oil natures, compositions, refining conditions and blending ratios. PC 32 technology is based upon a TOTAL-patented chemistry. TOTAL has been selling PC 32 to refineries, distributors and cargo treaters in more than 40 countries for more than 15 years. PC 32 offers the following advantages proven by laboratory tests: Improves lubricity properties of diesel fuels. Reduces fuel injection equipment wear and therefore improves engine durability. Protects fuel tank and lines against corrosion. Does not degrade injector cleanliness. RECOMMENDED DOSAGE PC 32 is a leading technology on the market. Recommended treatment level is between 25 and 300 ppm depending on diesel fuel nature and required lubricity target. However, in most cases, diesel fuel can be treated with less than 100 ppm to achieve mandatory specification. PC 32 offers one of the best treatment rates on the market. TECHNICAL SPECIFICATIONS UNIT TYPICALS SPECIFICATIONS TEST METHOD Appearance Yellow to dark Orange Visual Density at 15 C kg/m ASTM D1298 Flash point C 205 > 100 ASTM D93 Pour point C -12 < -6 ASTM D97 Cloud point C -10 ASTM D2500 Viscosity at 20 C mm²/s ASTM D445 Acid value mgkoh/g >193 ASTM D465 Saturated fatty acids %fatty acid <2.5% ASTM D5974 Unsaturated fatty acids %fatty acid >90% Internal GC I 5

6 AGREEMENTS NATO-CEPMA pipeline approval PC 32 has undergone laboratory screening and pipeline testing. It has been judged acceptable for transport in diesel fuel in the Central Europe Pipeline System. UFIP-TRAPIL technical advisory Considering the absence of any changes in technical characteristics of jet fuel during either laboratory tests or pipeline tests, PC 32 obtained the UFIP- TRAPIL Technical Advisory. British Pipeline Agency Limited (BPA) Products treated with PC 32 are permitted in UKOP Thames Mersey Pipeline System. The additive has been approved after showing no harmful effects on trials working under UKPIA/ IP protocol guidelines. DGMK Approval To obtain DGMK approval, PC 32 was evaluated with success on the following criteria: Compatibility with engine oils Emulsion behavior Storage behavior Compatibility with WASA and MDFI additives Compatibility with performance additives Stability to oxidation EPA registration PC 32 has been registered by the United States Environmental Protection Agency since I 6

7 PC 32 PUT TO THE TEST LUBRICITY EFFICIENCY Lubricity Response of PC 32 compared with Ester-type additive MWSD, µm 600 Ester-type Additive PC 32 EN590 Specification Production Target Dosage, ppm A treatment rate of less than 100 ppm is sufficient to reach the 460 μm specifications whereas 130 ppm of a ester-type additive would be required. Moreover, the 400 μm limit can also be reached with a treatment rate of 150 ppm. NB: each data point has been doubled ensuring an internal repeatability of 25 μm. PC 32 Lubricity response on ULSD Fuels MWSD, µm Diesel #1 Diesel #2 Diesel #3 Diesel #4 Diesel #5 Diesel #6 Diesel #7 EN590 Specification Production Target Dosage, ppm I 7

8 THE ADVANTAGES OF THE MONO-ACID TECHNOLOGY PC 32 exceptional lubricating properties also stern from its acid nature. Indeed, oxygenated moieties enhancing lubricity can be ranked as follows 2 : This explains that free fatty acids such as PC 32 possess significantly better lubricity properties than corresponding fatty alcohols and neat esters. Carboxylic acid Aldehyde Alcohol MethylEster Cetone Ether O O O O Furthermore, as shown on the previous chart, the capacity of Mono-Acid LI to meet the ISO specification more rapidly than Ester-type LI has been confirmed in several studies 3 and can be applied to most diesel fuels. R = C OH R = C H R C OH R = C O CH 3 = C R 1 R 2 O R R PC 32: ONE OF THE MOST COST EFFECTIVE SOLUTION ON THE MARKET RELATIVE MARKET PRICE x TREATMENT RATE TO REACH 460 μm = RELATIVE TREATMENT COST PC 32 $$ x = $$ 100 ppm Ester-type Additive $$ $ x 130 ppm = $$ $$ Ester-type additization is typically twice as expensive as PC 32 additization. I 8

9 OPERABILITY AND SHELF LIFE PC 32 Shelf-life (without quality deterioration) is 24 months. Over this time PC 32 quality is not altered if subjected to normal handling procedures and storage conditions. In addition, experience at Total demonstrates that PC 32 can be stored in outdoor conditions while retaining its appearance and properties after 24 months. The temperature range recommended for PC 32 storage and handling is between -6 C and 40 C. Short-term exposure to temperature outside this range does not affect product stability and properties. PC 32 is not hazardous to personnel and is not classify as dangerous product. Handling and storage conditions of various lubricity improvers PC 32 ESTER-TYPE CHEMISTRIES TYPICAL FATTY ACID Storage temperature -6 C to 40 C -5 C to 40 C 20 C to 40 C Pour Point -12 C -3 C to 6 C 5 C INTERNAL DIESEL INJECTOR DEPOSIT (IDID) This test aims to assess the innocuity of the additive regarding the formation of soaps and lacquers on the injector needle of a Renault K9K Engine (CDI). Deposit on Injector Needle: PC 32 vs. Ester-type Additive B7 + PC 32 (Mono-Acid) B7 + Ester-type Additive Both technologies do not induce the generation of IDIDs. I 9

10 STABILITY TEST Three different types of additives underwent a stability test: A typical Fatty Acid A typical Ester-type Additive PC 32 In the picture below, samples in the foreground are the additives before the test, and samples in the background are the same additives 5min after termination of the test. Protocol of stability test: Temperature cycle: 12h at 20 C, 6h at 0 C, 6h at -10 C. Cycle is repeated 5 times LI additives before and after a stability test 55 min after the end of the test, only PC 32 is a homogeneous liquid. Therefore, unlike some other lubricity additives, PC 32 does not require heated tanks (nor dilution with kerosene) to be stored 1. Fatty Acid Ester-type Additive PC 32 5 min after test Before test 1 In Areas where outside temperature doesn t drop below -10 C I 10

11 DEMULSIFICATION TEST The standard method used for this test is ASTM D It was originally designed to determine the presence of water-miscible components in avgas and turbine fuels and their compounds on volume change and on fuel-water interface. Protocol: {80ml of Ref fuel + 20ml of Water (ph =7) + 200ppm additive} are shaken during 2minutes. After 5 minutes, quotations are made. It has been used here to determine the effect of 3 different additive types on a reference ULSD fuel regarding demulsification. The results are shown in the table below: Demulsification test results WATER VOLUME SEPARATION RATING INTERFACE RATING Ref Fuel 20 ml (1) Absence of emulsions and/or precipitates within layer or upon the fuel layer (1) Clear and Clean Ref Fuel + 200ppm Fatty Acid 20 ml (1) (1) Ref Fuel + 200ppm Ester-type Additive 19,5 ml (2) Small air bubbles or water droplets in fuel layer (2) Shred, lace or film at the interface Ref Fuel + 200ppm PC ml (1) (1) Water/Fuel Separation after 5 minutes rest Ref Fuel + 200ppm PC 32 Ref Fuel + 200ppm Ester-type Additive While the fatty acid and PC 32 seem to have no influence on the demulsification property of the Diesel fuel, the Ester-type additive clearly deteriorates the ability of the fuel to separate from water. This characteristic is an important criterion for the evaluation of additives intended to be injected in fuel transported in multiproduct pipelines. = 0.5 ml I 11

12 PERFORMANCES TESTS: TOTAL ADDITIFS & CARBURANTS SPÉCIAUX EXPERTISE 3D Wear Scar on HFRR ball To get a deeper understanding of how wear occurs during HFRR tests, Total Research Center performed 3D surface analysis of HFRR balls using NPFlex, a 3D Optical Industrial Microscope. This yielded the following images 4 : ULSD MWSD = 620 μm ULSD + Ester-type additive MWSD = 352 μm ULSD + PC μm MWSD = 354 μm Those 3D surfaces have been analyzed using ISO (Geometric product Specifications). Despite similar results on HFFR, if we look at the depth of the wear scar, we can say that PC 32 protects the surface more effciently than the neutral additive by preventing from deep wear. Influence of additization on 3D wear scar ULSD ULSD + ESTER-TYPE ADDITIVE* ULSD +PC 32* HFRR - WSD (μm) Max depth (μm) Average depth (μm) ,1 Crater volume (μm 3 ) *Additization rate: 200ppm. I 12

13 BIBLIOGRAPHY 1. Fuel Requirements for Diesel Fuel Injection Systems Diesel Fuel Injection Equipment Manufacturers - Common Position Statement. Delphi, Bosch, Continental, Denso, Stanadyne Knothe, G. and Steidley, K. R. Lubricity of Components of Biodiesel and Petroidiesel. The Origin of Biodiesel Lubricity. Energy & Fuels. February 18, 2005, pp Hornby, B., et al. Pushing the boundaries of the HFRR: Impact of Increased Test Severity on Wear. s.l.: SAE International, TOTAL - Centre de Recherche de Solaize. NPFlex Tests I 13

14 TOTAL ADDITIFS & CARBURANTS SPÉCIAUX 3, place du Bassin Givors France Sales Department: +33 (0) Société par Actions Simplifiée au capital de euros Siège social : 3, place du Bassin Givors RCS Lyon acs.total.com