Classification: Internal Status: Draft

Cold Climate Lubrication(the Swedish Experience)

"Lubricants Russia 2007", November 28 – 29, MoscowProf. Thomas Norrby

Manager R&D, Statoil Lubricants,

Sweden

stnb@statoil.com

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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

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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

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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 phasesonce formed

• Important factors are:

– Wax content of the fluid

•Varies with type, source, and refining

– Pour Point Depressant (PPD) chemistry

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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

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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)

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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)

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Development of Turbine EALs

•Research with Luleå University of Technology started in 1997revealed 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

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Two-stroke engine oil

•Novel bottoms-up designed EAL 2T

•Offers superior cold-starting performance insystems 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

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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

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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!

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Saturated fatty acids Un-saturated fatty acids

KV 40 C ca 20 cSt KV 40 C ca 44 cSt

Typical ester base fluids

Alcohol-part is a neopentyl glycol

(in this case trimethylolpropane)