Classification: Internal Status: Draft

Cold Climate Lubrication ( the Swedish Experience)

"Lubricants Russia 2007", November 28 – 29, Moscow

Prof. Thomas Norrby

Manager R&D, Statoil Lubricants, Sweden [email protected]

Today’s presentation

• Cold climate lubrication challenges • Rheology and fluidity stability • Some examples from different product groups and applications – Hydraulics, hydro power, and 2T oils • Experiences from field applications of EALs (Environmentally Adapted Lubricants) • Technical standards and testing • Conclusions 2

Cold climate lubrication challenges

• These are mainly related to rheological properties, i.e. fluidity and flow characteristics after long-term storage or exposure ..

• ..but also to the interaction between cold fuel and lubricant, in a cold engine. Startability and lubrication is affected • Small 2T-engines like chainsaws, and snowmobiles (2T and 4T) are frequently used in cold climates 3

Rheology and stability

• Rheological properties, i.e. fluidity and flow characteristics • Long-term storage stability and start-up properties • Problems and challenges – Slow formation of waxy crystalline phases • 2-7 days of stand-still – Slow re-melting/thawing of crystalline phases once formed • Important factors are: – Wax content of the fluid • Varies with type, source, and refining – Pour Point Depressant (PPD) chemistry 4

Development of Hydraulic EALs

• Research with Luleå University of Technology since early 1990s • “Rena smörjan” (“Clean lubricants”) – A government-sponsored report 1992 • SMP Projects start ca 1992 – – – Now running SMP VI All-stakeholder project Successful investigation and solution of technical issues • Work with Eco Labels and standards – – Nordic Swan, SP List SS 15 54 34 HFs 5

Development of Hydraulic EALs

• A range of products in the market – Rape seed oil & ester mix based – PAO-based – Various ester based HFs • Unsaturated, long-chain • Saturated, short-chain • Hi-performance saturated synthetic esters have been around for many years – No significant market for vehicles has materialized (e.g. Panolin) 6

Development of Chain bar EALs

• Different sawing operations – Chain saws, chain bars, sawmills etc • In the market about 15 years • Early products were white oil-based: occupational health • Cutting in mechanized forestry • Tall oil based (from pine trees): a logical choice, nice product loop • Pine & pine LT – Phased out due to some technical problems, wrong price and competing raw material usage • Rape see oil based (total loss applications) • Synthetic ester based (sawmill) 7

Development of Turbine EALs

• Research with Luleå University of Technology started in 1997 revealed new knowledge regarding film formation • Retained film thickness, lowered visc.

• Extensive rig & field testing • EAL-type formulation – Extensive transfer of knowledge from previous generations of EALs • Offers 20-25% better bearing efficiency – ~1% overall improvement in electricity generation!

• Hydraulic gates and outdoor parts subject to exposure and stand-still • Technology applicable to many journal bearing applications 8

Two-stroke engine oil

• Novel bottoms-up designed EAL 2T • Offers superior cold-starting performance in systems with a separate oil tank • EAL profile, substantial content of renewable and biodegradable content • Patented two-stroke engine oil – Snowmobiles, small engines – Europe Patent # 1 383 852 B1 – Valid in Russia, Sweden, Finland and Poland • First markets - snowmobiles 9

10

Technical Standards and Testing

• The Swedish technical standard, SS 155434, incorporates requirements for maximum kinematic viscosity after 72 hours stand-still at -30  C (ISO VG 32) and -20  C (ISO VG 46 & 68). • ISO 15380:2002 has provisions for the testing of hydraulic fluids after low temperature storage for seven days, however without specifying limits. • Flow and shear properties, which may tested in a laboratory environment, include: – pour point (flow under gravity) ASTM D 97 – kinematic viscosity (flow under gravity in a capillary) ASTM D 445

Conclusions

• Low temperatures affect rheology – Non-Newtonian behaviour – Change after extended storage • Synthetic lubricants offer significant improvements in permissible operating conditions • Extensive experience of the field application of environmentally adapted lubricants has been accumulated • Technical standards offer useful guidelines •

Thank you for your kind attention!

11

Typical ester base fluids O Alcohol-part is a neopentyl glycol (in this case trimethylolpropane) O O O O O O O O O O O Saturated fatty acids Un-saturated fatty acids KV 40  C ca 20 cSt KV 40  C ca 44 cSt 12