Impact on Cylinder Lubrication by Changing Operating, Fuel and Engine Requirements

Transcription

1 The International Propeller Club Environmental, Energy, Efficient Management Operation in Shipping Seminar 22 nd of May International Port of Piraeus, Greece Impact on Cylinder Lubrication by Changing Operating, Fuel and Engine Requirements Ing. Bert Van Cleemput Technical Service Engineer Chevron Marine Lubricants Ghent, Belgium 2012 Chevron

2 Cylinder lubrication Maintaining the Acid-Alkaline Balance With the introduction of the ECA s, the sulphur levels in marine fuels are starting to vary more than ever. Also many ships apply slow steaming which impacts the way the engine is lubricated. Maintaining the acid-alkaline balance in an engine is becoming more challenging, as more variables come into play. Some of the variables which h affect this balance are: Sulphur content of the fuel (major) Base Number of the cylinder oil (major) Cylinder oil feed rate (major) Engine related variables: Moisture level in the scavenge air and scavenge air temperature Main engine cylinder bore and stroke Engine load and design

3 Cylinder lubrication Maintaining the Acid-Alkaline Balance Acid-Alkaline Balance Acid formation Introduced alkalinity

4 Cylinder lubrication Maintaining the Acid-Alkaline Balance Excessive corrosive Acid formation wear Introduced Alkalinity

5 Cylinder lubrication Maintaining the Acid-Alkaline Balance Source: MBD

6 Cylinder lubrication Maintaining the Acid-Alkaline Balance Scuffing initiated by corrosive attack Diluted Sulphuric Acid acts very corrosive on grey cast iron Pearlite & Graphite will wear more than the hardphase and allows oil to be entrapped ensuring proper lubrication Hard phase is needed for wear resistance Inter-crystalline corrosion matrix destroyed hard phase particles protruded or released P P=Pearlite G=Graphite Corroded surface extremely vulnerable to mechanical load St P G C P C=Cementite (hard phase) C C P Corrosive attack P

7 Hard phase break out due to sulfuric acid attack Source: Wärtsilä Switzerland Ltd. After cold corrosion of the liner => Grey cast iron piston ring with embedded hard phase Fe 3 C with a Vickers hardness of HV1200. These particles are extremely abrasive. Source : CIMAC Congress, Hamburg 2001

8 Cylinder lubrication Maintaining the Acid-Alkaline Balance With the naked eyee Liner surface shows open structure t Liner surface shows closed structure t as a result of metal smearing

9 Cylinder lubrication Maintaining the Acid-Alkaline Balance With digital camera, with or without macro zoom

10 Cylinder lubrication Maintaining the Acid-Alkaline Balance By taking liner replicas

11 Cylinder lubrication Maintaining the Acid-Alkaline Balance Replica: Cat Fines Replica: Hard phase (Cementite) break-out

12 Cylinder lubrication Maintaining the Acid-Alkaline Balance With a hand held microscopes

13 Cylinder lubrication Maintaining the Acid-Alkaline Balance

14 Cylinder lubrication Maintaining the Acid-Alkaline Balance Acid Formation Excessive top land deposit formation Introduced alkalinity

15 Cylinder lubrication Maintaining the Acid-Alkaline Balance Scuffing initiated by hard excessive deposit formation Piston crown land Liner Open cast iron surface is required for proper oil film formation Structure provides oil reservoir on liner surface and proper oil film formation Polishing due to crown land deposit contact (closed liner structure) Liner surface becomes too smooth Improper oil film formation Removal of oil film Metal-to-metal contact

16 Cylinder lubrication Maintaining the Acid-Alkaline Balance A PCR or ABPR helps to prevent scuffing but in some cases additional problems might occur: Piston crown land When no proper base sulphur-balance u a is achieved, the possible excessive deposits are scraped down and travel partly through the ring pack. This can cause increased wear and will cause most likely high ring groove clearance and will determine the TBO intervals! Liner Even with PCR or ABPR installed, touching from deposits to liners still possible.

17 Cylinder lubrication Maintaining the Acid-Alkaline Balance Abrasive polishing of liner surface

18 Cylinder lubrication Maintaining the Acid-Alkaline Balance Typical view of polished deposits with PCR/ABPR

19 Cylinder lubrication Maintaining the Acid-Alkaline Balance Update on the major OEM OFR guidelines Acid-Alkaline Alkaline Balance Acid formation Introduced alkalinity Chevron 2013

20 LSF Cylinder lubrication experiences OEM s point of view - MAN Chevron 2013 Source MBD

21 The MAN point of view Alpha ACC (Adaptive Cylinder Oil Control) Lubricator Source MBD Chevron 2013

22 The MAN point of view The MAN point of view Source MBD Chevron 2013

23 MAN D&T lubrication recommendations x %S (70BN) 0.35 x %S (40BN) Minimum 0.6 g/kwh 0.26 x %S (70BN) 0.45 x %S (40BN) Minimum 0.6 g/kwh L&K=1.20 (0.8min) g/kwh S= 1.4 (0.9min) g/kwh 1.1 (0.7min) g/kwh Chevron 2013

24 The MAN point of view For engine types: Mark 9 and further. E.g. S80ME-C9. All G-engines. We recommend to use Cylinder Lube Oil: For High Sulphur Fuel: Cylinder lube oil with 70BN or higher For Low Sulphur Fuel: Cylinder lube oil with 40BN or lower Cylinder lube oil viscosity: SAE50 Source MBD Chevron 2013

25 The WÄRTSILÄ point of view Chevron 2013 Source: Wärtsilä Switzerland Ltd.

26 The WÄRTSILÄ point of view Chevron 2013 Source: Wärtsilä Switzerland Ltd.

27 The WÄRTSILÄ point of view Chevron 2013 Source: Wärtsilä Switzerland Ltd.

28 Industry trends Marine industry Latest changes/innovations in the industry are driven by two key factors: Environmental legislation Vessel Operational Convenience - Lower cost - Reliability - Complexity reduction 2013 Chevron

29 Marine Emission Legislations Impact on the Industry Abatement technology allowed (scrubbers, ) l %S in fue 5 4,5 4 3,5 3 2,5 2 1,5 1 0, (May) 2006 (May) Marine Fuel Legislations (%S) 70 BN 2012 (January) DCL BN DCL??? 55 BN 2009 (May) + North Sea (July) 2012: (August: NA ECA) BN DCL IMO Decision Point BN DCL?? Global Average scenario 1: (4.5 > 3.5 > 0.5) Global Average scenario 2: (4.5 > 3.5 > 0.5) (S)ECA : (1.5 > 1 > 0.1) US/CANADA (S)ECA: (1 > 0.1) CARB MGO (DMA): (1.5 > 1.5 > 0.1) CARB MDO (DMB): (2 > 0.5 > 0.1) 10 BN DCL?? YEAR 2016: IMO Tier 3 Emissions 2013 Chevron

30 Chevron s countermeasures to meet LSF lubrication demands: Taro special HT LS 40 Chevron Marine Lubricants Cylinder Oil SAE Visc.Grade Base Number Application Taro Special HT LS Low Sulphur Fuels Taro Special HT Switching High/Low Sulphur fuels Taro Special HT High Sulphur Fuels Chevron 2013

31 Cylinder lubrication Maintaining the Acid-Alkaline Balance Finding the right Acid-Alkaline Balance helps optimising Acid-Alkaline operational Balance efficiency Acid formation Introduced alkalinity By adjusting the base number of the lubricant By adjusting the cylinder oil feed rate

32 The sulfur base balance theory: Confirmed under laboratory simulated engine conditions The test program demonstrated: the amount of corrosive protection, under the corrosive test conditions applied, is higher when higher BN products are tested. the amount of deposits on the piston top lands is lower when selecting lower-bn cylinder oils a clear inverse correlation between the corrosive wear and the amount of deposits formed Bolnes 3L Pmax: 130 bar Bore: 190mm Stroke: 350mm Speed: 500 rpm 2013 Chevron Fuel: 380cst / 0.6%S fuel Oil Feed: 0.7g/kWh - JC Water: 80 C

33 The sulfur base balance theory: Not always reflected in the field Lab testing is not always reproduced in the field! 70BN Cylinder Oil 40BN Cylinder Oil Top land deposit formation Minimum recommended OEM oil feed rate 0.5 to 1% Sulfur residual fuel (HFO) 2013 Chevron

34 Experience with Field Testing Distillate Fuel Chevron field test and monitor vessels with distillate fuels in slow speed 2-stroke engines since 2009! 40BN Cylinder oil, 70% over-lubricated according to minimum OEM recommendation The negative impact of overfeeding accelerates when engines are running on these very low sulfur fuels (<0.1%S) and leads to ring scuffing, ring breakage and bore polishing, in sometimes in less than 100 operating hours in CARB on 0.1 wt% S distillate fuel Chevron

35 Chevron s countermeasures to meet LSF/Slow Steaming lubrication demands: DOT.FAST Drip oil analysis is more important than ever in achieving reliable operation Onshore drip oil analysis + Onboard drip oil analysis FAST Drip Oil Analyzer A dedicated DOT.FAST Team that provides: - Additional support - In-depth analysis with on-shore testing Chevron 2013 Chevron s proprietary on-board DOT.FAST Drip Oil Analyzer provides you with: -immediate & accurate results to control cylinder/piston ring wear - optimize cylinder lube oil consumption

36 The DOT.FAST Service A tool to help you achieve the optimum Acid-Alkaline Alk li Balance And improve engine reliability Drip Oil Technology

37 The DOT.FAST Service What is Drip Oil? Drip Oil is the unburned cylinder lubricant, scraped down from the liner walls during each stroke of the engine. Drip Oil Samples are taken from scavenge space drains of each unit. Newly built engines are already equipped with drain cocks and sampling valves for this purpose (For older engines, the installation of Drip Oil Sampling valves can easily be justified by the benefits). Source: Wärtsilä Switzerland

38 The DOT.FAST Service What is Drip Oil? Testing Drip Oil provides useful information about engine performance. The measured iron indicates the wear that has taken place on the piston rings and liners in the specific cylinder. The measured base number reflects the residual base reserve which remains in the cylinder lubricant after combustion.

39 The DOT.FAST Service Why do Drip Oil Analysis? Drip Oil Analysis is specially dedicateddi d for monitoring i the running conditions of two-stroke engines. Drip Oil Analysis fits in any condition-based monitoring program and can be a tool to: Detect wear and monitor general engine performance Follow-up wear and BN during oil feed rate adjustments and while corrective actions are taken Optimise oil feed rate Monitor running-in of new units after overhauls Achieve maximum Time Between Overhauls Measure system oil leakage Detect problems with fuel purifier operation by measuring cat fine levels

40 The DOT.FAST Service How to monitor the Sulphur/Base balance? Iron Content as function of BN Oil feed rate is optimised by finding the balance between BN value and Iron content! Engine and sulphur dependent!

41 The DOT.FAST Service Onboard/Onshore Analysis Onboard Base Number Indication of the consumed base in the cylinder during combustion of the fuel Iron Level Indication of liner and ring wear Onshore Base Number Indication of the consumed base in the cylinder during combustion of the fuel Iron Level Indication of liner and ring wear Aluminum and Silicon Levels Indication of the presence of catfines Chromium Level Indication of ring groove wear Copper Level Indication of running-in, skirt wear, or stuffing box wear Vanadium Level Blow by (difference units) Manganese Level Liner scuffing (engine specific) Zinc Level Indication of system oil leakage through the stuffing box and/or piston

42 The DOT.FAST Service Onboard/Onshore Analysis Principle of the DOT.FAST Drip Oil Analyzer Unique, innovative and accurate! Measures adhesive, abrasive and corrosive wear! A fixed amount of lubricant is added to a fixed amount of specific solvent where an active agent turns all iron into a violet complex. The intensity of the color is evaluated by a VIS photometer. This is a measure of the iron content in the lubricant (expressed in ppm). It gives unbiased tests results, in comparison with the standard laboratory test method in the range of interest (up to 400-ppm iron).

43 The DOT.FAST Service Onboard/Onshore Analysis

44 The DOT.FAST Service Onboard/Onshore Analysis Industry standard d test tmethods run in a high quality certified laboratory. A well-structured report with professional comments and recommendations!

45 The DOT.FAST Service How to monitor the Sulphur/Base balance? BN Fe relation

46 Conclusion Maintaining the acid-alkaline balance in an engine is becoming more challenging, as more variables come into play The sulfur base balance theory: Confirmed under laboratory simulated engine conditions Not always reflected in the field Drip oil analysis is more important than ever in achieving reliable operation

47 Thank You! 2013 Chevron Picture: Chevron DAM/CBRES