1 COPYRIGHT 2020, LUBES’N’GREASES MAGAZINE. REPRODUCED WITH PERMISSION FROM THE 25TH ANNIVERSARY ISSUE

The Age of Group IIBY STEVE HAFFNER

When Lubes’n’Greases was in its infancy, the AmericanPetroleum Institute’s base oil groups were just a couple ofyears old, and API Group I was the base stock of choice formost lubricants. In the mid-1990s, new refining technologywas being scaled up that could deliver better base stock per-formance and more efficient production. These advance-ments would eventually turn Group II oils into the workhorsethat they are today, making up 40 percent of the world’s baseoil production capacity.

In 1993, the American Petroleum Institute classified basestocks into five groups, with Group I, II and III paraffinic min-eral oils categorized by saturates, sulfur and viscosity index.Polyalphaolefins got their own category, Group IV, and GroupV encompasses all other base stocks, including naphthenics.

Group II was defined as having saturates greater than 90 per-cent, sulfur less than 0.03 percent and a viscosity index between80 and 120. API Group III base stocks have a viscosity indexgreater than 120.

COPYRIGHT 2020, LUBES’N’GREASES MAGAZINE. REPRODUCED WITH PERMISSION FROM THE 25TH ANNIVERSARY ISSUE 2

Chevron’s 25,000-barrels-per-day API Group II base oil plant in Pascagoula, Mississippi (Photo: Chevron)

Chevron began to develop a selective waxisomerization process. Instead of remov-ing wax molecules as in solvent dewaxingor cracking them into light hydrocarbonsas in catalytic dewaxing, the Isodewaxing-branded catalyst and technology isomer-izes the wax molecules—rearranging theatoms to form new molecules—into lowpour point lubricating base oil.Launched in 1993 at Chevron’s

Richmond plant, this new process repre-sented a breakthrough improvement inhydroprocessing technology. “TheIsodewaxing catalyst significantly increaseslubricant base oil yield over competitivetechnologies [solvent dewaxing, catalyticdewaxing],” said Bharat Srinivasan,Chevron’s managing director of technolo-gy marketing. “It also can significantlyimprove the product’s V.I. due to the iso-merization of wax, which is the highest V.I.component, into the base oil fraction.”The technology “made it possible for

refiners to produce large volumes ofhigher quality base oil economically,” heboasted, which “has led to the steadyincrease of premium base oil productionworldwide.”Brent Lok was a green engineer in the

mid-1980s when he began working on

Industry veteran Terry Hoffman, for-merly of Sunoco, remarked that the firstGroup II-type oils appeared in 1971when the first hydrocrackers wereinstalled in Japan and at the company’sYabucoa, Puerto Rico, refinery. “Theseinitial base oils were introduced usingGulf Oil technology. The early process tomake Group II at Yabucoa used furfuralsolvent extraction to reduce aromatics,then hydrocracking to further reducearomatics and increase V.I.,” heexplained.“Another furfural extraction step

[achieved] color stabilization, and finallyvacuum distillation was used to cut thematerial into 40, 50, 70, 100, 170 and 300[Saybolt Universal Seconds] viscositybase oils.” Hoffman noted the early 100solvent neutral cut only had a viscosityindex of 90, which was much lower thanthe 100 to 110 V.I.—and even higher foroils marketed as Group II+—that formu-lators see today. Plants with the new technology could

also make base stocks from crude thatcould not be used by solvent processingrefineries. The next Group II plant started up

around 1978 at what is now Petro-Canada’s refinery in Mississauga, Ontario,followed by Chevron’s Richmond plant in1984. These early facilities struggled toraise viscosity index in light neutral cuts(SN 100, 150 and 220) without significantreductions in the volumes that the plantscould produce.Viscosity index and pour point are two

competing property targets for base oils.Normal paraffins, or waxes, have thehighest V.I., but their pour points are pro-hibitive for base oil applications. To meetthe pour point target, solvent dewaxingremoves wax from the base oil fractions.Catalytic dewaxing was also developed

in the 1970s to remove wax from oil. Itprovided an alternative to solvent dewax-ing because it separated normal paraffinsand waxy side chains from other mole-cules by catalytically cracking them intolight hydrocarbons. In the mid-1980s,

the new technology. After it made itsdebut, “I participated in an internal studyteam that recommended Chevron licensethe technology rather than keep it pro-prietary to advance the overall use ofGroup II technology in the marketplace,”Lok recalled. “It has been quite gratifyingto see the phenomenal market growth ofGroup II and III base oils to where it istoday.”Jirong Xiao, Chevron Oronite’s vice

president of sales and marketing, was alsoa young engineer on the Isodewaxingproject. “No one spoke in terms ofGroup I or II, as API had not officiallyclassified base stocks back then, but justhow we could transform to higher qualitybase stocks that could extend oil drainsand allow for higher quality lubricants,”he noted. Xiao pointed out that lubricant additive

companies were also able to take advan-tage of Group II base stocks. Everyoneunderstood the oils’ improved oxidativeproperties and their ability to yield prod-ucts at lower viscosity, lower volatility andhigher V.I., which enabled better fuelefficiency. But soon the industry foundother benefits, such as lower additivetreat rates to meet sludge and deposit

3 COPYRIGHT 2020, LUBES’N’GREASES MAGAZINE. REPRODUCED WITH PERMISSION FROM THE 25TH ANNIVERSARY ISSUE

North American Base Oil Capacity Shifts

requirements as well as the ability to han-dle soot in diesel engines.Mike McMillan, former manager of the

Lubricant Chemistry and Systems Groupin the Chemical & EnvironmentalSystems Laboratory at General MotorsR&D, was one of the first on the automo-tive side of the lubricants business tonotice the opportunities brought byGroup II base stocks. “GM first tookadvantage in their factory-fill applicationswhen we had Sunoco and Petro-Canadaas key suppliers,” he said. “SAE 5W-30 [engine oil] was rolling out

to the marketplace, and Group II basestocks not only facilitated improved fueleconomy for that viscosity grade, theyalso provided a lubricant that had superi-or oxidation properties and eventuallyallowed for a step-change in oil volatilityfrom 22 percent to 15 percent Noackwhen ILSAC GF-3 performance require-ments were [proposed] around 1996,”McMillan continued.He also noted that further advances

with Group III and Group III+ basestocks later enabled General Motors tomove to SAE 0W-20 lubricants with evenmore stringent oxidation and volatilityrequirements.ExxonMobil first began producing

Group II base oil in 1997 at its Jurongrefinery in Singapore. Those oils madetheir debut in North America at theBaytown refinery in 1999. Ted Walko,base stocks & specialties marketing man-ager, told Lubes’n’Greases that “the deci-sion to invest in Jurong was driven byExxonMobil’s desire to serve the growingdemand for Group II base stocks in Asia-Pacific.” “At the time, most lubricants were for-

mulated with Group I base stocks; how-ever, as the advantages of Group II—par-ticularly its improved oxidation stability—became more well-known in the industry,ExxonMobil anticipated that more andmore formulators in Asia-Pacific wouldconsider a switch,” he explained. Theproducer was able to utilize Jurong’sexisting structure, which came at a lower

COPYRIGHT 2020, LUBES’N’GREASES MAGAZINE. REPRODUCED WITH PERMISSION FROM THE 25TH ANNIVERSARY ISSUE 4

initial cost and provided a technologybase that could be readily expanded tomeet increasing demand. The Group II upgrade at Baytown was

completed in 1999 in anticipation of therollout of ILSAC GF-3 and its lower volatili-ty requirements. According to Walko, “thisled to ExxonMobil’s investment in raffi-nate hydroconversion technology thatleveraged the existing solvent refiningprocesses at Baytown to produce the lightneutral base stock required for GF-3.”Rick Dougherty, ExxonMobil’s

basestocks & specialties technologychief, added, “ExxonMobil produces basestocks through several of its proprietaryselective catalytic dewaxing processesthat offer higher yields, contaminant tol-erance and higher activity, leading tolonger life of the catalyst.”The company first commercialized its

Mobil Lube DeWaxing process forGroup I base stocks in 1981 at itsAdelaide, Australia, refinery. Based onthe ZSM-5 aluminosilicate zeolite cata-lyst, MLDW technology was designedfor dewaxing raffinate, but was laterlicensed to several Group II base stockproducers, Dougherty said. “ExxonMobil began development of its

own isomerization dewaxing technology,Mobil Selective DeWaxing, which was firstcommercialized at its Jurong refinery. In2000, ExxonMobil commercialized thesecond generation of its MSDW technolo-gy at Jurong with industry-leading selec-tivity for both light and heavy stocks,” hecontinued. Over the years, ExxonMobilhas continued to innovate with new andimproved catalysts as well as advances inhydrocracking technology, most recentlydeployed at its API Group II plant inRotterdam in early 2019.Gerry Jackson, vice president of busi-

ness development with Renkert Oil,recalled that selling Group II base oil waschallenging in the beginning. He hadworked on the 1995 startup of the ExcelParalubes plant in Westlake, Louisiana.“Early times were challenging, as thevalue of Group II was not reflected when

ILSAC GF-2 was introduced,” he said.Motiva in Port Arthur, Texas, converted

one of its Group I trains to Group II in1998, then converted the other in 2001.Jackson was working for the producerwhen it streamed its new base oil hydroc-racker in 2005. “Moving 41,000 barrels perday was initially challenging, but with ILSACGF-3 the industry began taking advantageof the newer base stocks and the qualityadvantages they offered. Then we startedseeing Group II postings in industry publi-cations, and the [price] separation betweenGroup I and Group II began.”“The last 25 years have seen remarkable

change for base stock manufacturing,including the validation of Group II oils,the rise of Group III because of the avail-able new technology, as well as the firstworld-scale gas-to-liquids plant,” Jacksonconcluded.Over the next 25 years, the drive

toward even lower viscosity oils is expect-ed to spur advances in API Group III andnon-conventional base stocks to meetfuel savings targets without negativelyimpacting volatility or low-temperatureperformance. API Group II is poised to be the domi-

nant base stock for the next decade, andwith their increasingly higher viscosityindex, these oils will combine with GroupIII to meet much of the world’s lubricantdemand. Refiners around the world also are

rethinking their distillate slates in responseto the International MaritimeOrganization’s new curbs on burning high-sulfur fuel at sea. “IMO 2020 may also havean impact on some Group I refineries that,in turn, could accelerate the growth ofGroup II in lubricants applications,”ExxonMobil’s Walko predicted. “In the future, quality and technical per-

formance of base stocks will also becomemore prevalent, and … the industry mustadapt to the changes in the base stockbusiness. We believe that productioncapacity should adjust over time in linewith demand trends—although it isalways difficult to predict the pace.” �