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Lube- · PDF filehydroprocessing technology All-hydroprocessing for base oils starts with the same feed as a solvent plant. However, instead of using a solvent to

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  • L U B E M A G A Z I N E N o . 1 0 7 F E B R U A R Y 2 0 1 22


    Modern Base Oils & Blending for Optimal PerformanceMeeting the Evolving Needs of theEuropean Lubricant MarketThe lubricants industry in Europe is at acrossroads. Historically, lubricant form-ulations have been based uponoptimising Group I, Group III or a GroupI/III blend with a proven additive package.

    Relying on Group I and Group III hasserved the European lubricants industryexceptionally well. Group I is readilyavailable, and typically, is the leastexpensive base oil. Historically, it hasbeen the dominant ingredient in manylubricant formulations, particularlyindustrial lubricants and automotiveformulations with a lower viscosity index(VI). As a result, Group I has become thework horse base oil throughout Europe,whilst Group III has been used to deliverhigher performance and lower viscosity.

    With tightening environmental legislationthis historical balance is beingchallenged. In order to meet greeninitiatives, the Automobile ManufacturersAssociation (ACEA) is pushing for tighterengine oil specification standards.

    This has created a maze of OEMrequirements that call for emissionsystem protection and extended drainintervals from both Passenger Car MotorOils (PCMO) and Heavy Duty Motor Oils(HDMO). Meeting those specificationsrequires lubricants with lower viscosityand lower volatility.

    In addition to tightening performancerequirements for crankcase lubrication,automatic transmission fluids, greasesand industrial oils are also facing tougherchallenges. Automatic transmissions are

    being redesigned to boost fuel economyand are moving to fluids that can providefill-for-life performance. Greases arebeing subjected to higher loads, higherbearing speeds, and higher temperaturesthat require formulations with betteroxidation and thermal stability. Similarly,users of industrial lubricants want betterthermal stability and longer oil life.

    Generally speaking, these performancetrends are calling for base oils that have Higher VI to enable better fuel

    economy and low volatility Lower volatility for reduced oil

    consumption Practically zero sulphur Excellent oxidation stability High saturates content for improved

    additive response

    Whilst these new standards are verygood for the environment, they arecreating significant challenges forlubricant manufacturers who mustgrapple with optimising lubricantformulations for new specifications whilstmanaging supply chain cost andcomplexity. New premium quality baseoils will need to be added to the supplychain in order for blenders to meet thefull range of new specifications for their Automotive Engine Oils (AEO).

    This means increasing tankage toaccommodate additional base oils or re-evaluating formulations across a blendersentire product line and identifyingopportunities for reformulating with newpremium base oils.

    Careful selection of base oil suppliers willhelp reduce potential supply chaincomplexity and cost. Given the complicatedand costly process for qualifying lubricants,selecting base stocks from suppliers withlarge volumes and multiple plants helpsminimise the need for expensive requalifi-cation testing with alternative base stocks.This also reduces tankage requirements.These challenges have brought a newlevel of scientific sharing between OEMs,lubricant manufacturers, additivecompanies and base oil suppliers to findsolutions that optimise performance andmeet market demands.

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    Lube-TechMeeting New Mid/Low SAPSRequirements A Blending Challengefor Lubricant ManufacturersOf particular concern, is how to optimiseblending strategies for AutomotiveEngine Oils (AEO) in light of new specifi-cations. Group I base stocks are high inaromatics, sulphur and nitrogen, all ofwhich have a negative impact onlubricant performance. Historically, as theneed for improved product qualityincreased, some combination of theadditive treat rate and the amount ofGroup III were increased to compensatefor the impurities/inefficiencies in Group Ibase stocks.

    In response to the introduction of Euro Vand VI emission regulations, OEMs havemodified their engine designs andemission control systems to reduce thelevel of nitrogen oxides and particulatesreleased into the atmosphere. One of thesolutions was to install after treatmentdevices, such as diesel particulate filters(DPFs) and selective catalytic reductionunits (SCRs).

    Protecting the performance of thesedevices drove the need for newEuropean specifications that restrict thelevels of sulphated ash, phosphorous andsulphur (SAPS) in motor oils. In responseto these tightening standards, newcategories of Mid and Low SAPSengine oils have been designated.

    Significantly, given the high amount ofsulphur in Group I base oils, they cannotbe used in AEO formulations designedfor Mid or Low SAPS specifications.This creates a significant challenge forproducers of 10W-XX and 15W-XXmultigrade lubricants, which account formore than 85% of the European finishedlubricants HDMO market. Group III alonehas insufficient viscometrics to meet theperformance requirements for heavier

    motor oil grades and Group I has toomuch sulphur for the new specifications.

    This is the crossroads for Europeanlubricant manufacturers. The challengelies in meeting the requirements for Midand Low SAPS lubricants whilst providingthe necessary performance for enginesrequiring 10W-XX and 15W-XXlubricants. This is particularly true forheavy-duty engines. Large diesel enginesare subjected to demanding workloads.They typically operate at low speeds andvery high torque. Their engines requirelubricants that provide sufficient hightemperature/high shear (HTHS) character-istics to insure adequate wear protectionand maximise engine durability.

    To meet this challenge European blendersare evaluating the range of base oilsavailable and their impact onperformance and supply chaineconomics.

    Alternative Base OilsThe ATIEL and API base oil classificationsystem groups base oils based on theirpurity and VI. It was established to helpmarketers minimise re-testing costs whenblending licensed engine oils with baseoils from different manufacturingsources. The system uses physical andchemical parameters to divide all basestocks (oils) into five Groups Groups I.II, III, IV and V.

    Base stocks, even in the same Group,may differ widely in their molecularcomposition, and physical and chemicalproperties depending on the feedstockand processing parameters used by therefiner. Differences in base stockcomposition affect the performance offinished lubricants, consequently, basestocks are considered non-fungible inmany lubricant formulations. This isparticularly true in high performance

    automotive engine oils. As a result,supply reliability of fungible base stocksshould be a critical consideration in theearly stages of new lubricantformulations.

    Where Automotive Lubricants go, Base Stock Characteristics goAutomotive lubricants demand morethan half of all base oil production.Additionally, they have strictrequirements for physical and chemicalproperties. So refiners, within thecapabilities of their processing scheme,design the physical and chemicalproperties of their base oil production tomeet the performance requirements ofautomotive lubricants.

    Refiners can influence the characteristicsof their base stocks by feed stockselection, processing severity andcatalyst selection. But, by far, the mostsignificant limiting factor on base oilquality is the manufacturing processused by the refiner. There are twogeneral processing schemes forproducing mineral oil base stocks. Theolder process, solvent dewaxing wasdeveloped in the 1920s and is used forproducing Group I base stocks. Thesecond, an all-hydroprocessing schemeChevron introduced in 1993 usesisomerisation for dewaxing. It is used tomake Group II/III base stocks.

    Group I Base Stocks Excellent for many industrialapplications, but too much sulphurfor tightening AEO specificationsProducing Group I base stocks starts withvacuum gas oil (VGO), one of the heavierstreams coming out of the crude unit.Solvents are used to selectively remove50-80% of the impurities. However, thetreated base oils stream still has paraffinsthat need to be removed to produceusable base stocks.


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    The paraffins are removed by a dewaxingprocess that uses solvents taken to a lowtemperature, where the wax is precipitatedout. The resulting Group I base stock hasrelatively high sulphur making it unsuitablefor Mid and Low SAPS AEO specifications.

    Group II/III Base Stocks All-hydroprocessing technologyAll-hydroprocessing for base oils startswith the same feed as a solvent plant.However, instead of using a solvent toremove undesirable compounds, the feedis processed in a high-pressure hydro-cracker with catalysts that reshape themolecules, saturate the aromaticcompounds and create high quality isoparaffins. In total, 98-99.9% of theimpurities are converted to high qualitybase oils. Chevron invented thisprocessing scheme in the 1990s andtoday more than two thirds of theworlds premium base oil is producedusing this upgrade path.

    Whilst the same upgrading technology isused for producing Group II and Group IIIbase stocks, the driver for which grade arefinery produces is the source of thefeed - a large diesel hydrocracker vs agasoline hydrocracker.

    Group II is typically produced byprocessing VGO in a dedicated base oilhydrocracker in a gasoline refinery.Gro

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