HEALTH AND SAFETYASPECTS OF

NAPHTHENIC OIL

www.nynas.com/naphthenics

HEALTH AND SAFETYASPECTS OF

NAPHTHENIC OIL

1 INTRODUCTION 11.1 Oils and their environmental impact 11.2 Natural resources and energy 21.3 Effects on human health and the environment 21.4 Waste 3

2 CLASSIFICATION AND ASSESSMENT 42.1 Chemical substances - product streams 42.2 Mixtures of substances 5

3 PRODUCT INFORMATION IN SDS 63.1 Identification of the substance/preparation 73.2 Composition 73.3 Dangerous properties 73.4 Physical and chemical properties 73.5 Toxicological information 73.5.1 Acute toxicity 83.5.2 Oils and toxicity 83.5.3 Local effects 93.5.4 Skin delipidising 93.5.5 Oils and local effects 93.5.6 Sensitisation 103.5.7 Oils and sensitisation 103.6 Chronic toxicity/long-term effects 103.6.1 Mutagenicity 103.6.2 Carcinogenicity 113.6.3 Teratogenicity 123.7 Oils and long-term effects 12

CONTENTS

3.8 Ecological information 143.8.1 Mobility 143.8.2 Persistence/degradability 143.8.3 Bioaccumulation 143.8.4 Ecotoxicity 14

4 METHODS, TESTS AND ORGANISATIONS 16

4.1 Skin irritation tests 164.1.1 Method 164.1.2 Results 164.2 Biodegradability 174.2.1 Marine discharges of crude oil 174.2.2 Oil escapes on shore 184.2.3 Refined oils 184.3 The Ames Test 194.4 Life-cycle analysis 204.4.1 ELU value of Nynas oil 214.5 Organisations and authorities 234.5.1 CONCAWE 234.5.2 Directorate General XI (DGXI) 24

5 APPENDIX 255.1 Chemistry 255.1.1 Chemical composition 255.2 Methods of PAC analysis 265.2.1 IP 346 265.2.2 HPLC 275.2.3 Gas chromatography 275.3 Refining technique 285.3.1 The various stages of refining 285.3.2 Distillation 295.3.3 Solvent refining 295.3.4 Hydrotreatment 305.3.5 Acid clay treatment 31

1 INTRODUCTION

Safety Data Sheets are by nature brief and leave many questions unans-wered. We are often approached by customers who need more informa-tion than is supplied by the sheets: they might want to know what isthe difference between a preparation and a substance; or why one oil islabelled and another with the same values is unlabelled; or what shouldbe done following skin contact with a particular oil. This handbookaims to answer these questions, while providing a summary of current(1997) knowhow concerning the labelling, toxicity and environmentalrisks of oil products.

The environmental effects of industrial products are a topic of growingconcern. The Nynas Group is engaged in environmental work withinthe oil industry organisation CONCAWE and the European ChemicalIndustry Federation, CEFIC. As a result, the group companies areworking in compliance with the CEFICs Responsible Care pro-gramme and have comprehensive systems for labelling of productsaccording to EU requirements and ISO 11014.

With regard to Nynas Naphthenics product slate, labelling has led tothe decision to stop the production and marketing of toxic products. AtNynas Naphthenics, it is our aim to maintain a high degree of environ-mental awareness and to act accordingly.

Mineral oils are complex materials, and both their environmentalimpact and safety aspects demand careful consideration. This handbookdeals with aspects of European Union law and looks at some of our in-house research findings which substantiate our labelling practice.

This handbook has been compiled as a complement to NynasNaphthenics Safety Data Sheets (SDS). Information specific to indivi-dual products is supplied in SDS which are obtainable from our salesoffices.

1.1 OILS AND THEIR ENVIRONMENTAL IMPACTIn order to assess the environmental impact of a product, it is necessaryto perform a life-cycle analysis (see Life-cycle analysis, section 4.4).This serves to identify all potential sources of environmental impact:from sourcing and transport of the raw material, through productionand distribution, to use and final destruction.

A life-cycle analysis is not complete unless transport and refiningoperations, which of course involve energy consumption, are includedin the analysis, although these factors are not specific to the productionof oils.

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An important question regarding the environmental impact of oils con-cerns their degree of biodegradability (see Biodegradability, section 4.2)and whether they are toxic - and if so, how toxic - to flora and fauna.Decomposition products also have to be evaluated for toxicity.

1.2 NATURAL RESOURCES AND ENERGYAll use of crude oil involves the exploitation of a finite natural resource.Since total world use of oil is great in relation to existing reserves, themagnitude of this consumption can be considered to cause serious envi-ronmental impact.

Here we might add that when a given quantity of oil is used as trans-former oil, it has a working life that can be measured in decades. Thiscan be compared with the same amount of oil which when used as fuel,would be transformed into exhaust fumes within a matter of hours ifused in a powerful speedboat. Furthermore, the inherent energy in thetransformer oil remains unused even at the end of its useful lifespan andcan either be combusted and converted into energy, or recycled.

Figure 1 describes the proportion of oil used as base oils, in comparison with fuel oil and bitumen. Seen in these terms, transformer oils accountfor only 0.01%, for example.

1.3 EFFECTS ON HUMAN HEALTHAND THE ENVIRONMENT An oil can prove to be harmful to human health. The risk of healthhazards can range from high, to practically zero, depending on the oilchosen and type of application. As for the oil itself, it is the degree ofrefining which decides whether or not it can be harmful to the health(see Refining technique, in the Appendix).

Oil spillage into the soil or water is another important issue. Thoughspillage should, of course, never occur, the risk exists and the conse-quences have to be examined. Here again, the composition of the oilmakes a difference, although the damage depends mainly on the size ofthe spill and the environment in which it occurs.

3% Bitumen1% Base

oil

96% Fuel

2

1.4 WASTEWaste can be generated in the course of production, or it can constitutethe remains after the product has been used. (Internal waste is discussedin section 4.4.1). The appropriate treatment of the used end productvaries from one application to another, depending on whether the oilhas been used, for example, as a plasticiser for rubber, a solvent forprinting ink or as an industrial lubricant. However it has been used, itis very important that the used oil should be collected.

In the case of lubricating oils, it is commonly held that they can bepurified and reused, while others maintain that they should be burned.The argument in favour of combustion is that, as long as feedstock forbase oils are still used in large quantities as heating oils, recycling of theoil contained in used lubricants is not worth the trouble. Moreover,additives and contaminants in the lubricant may be easier to deal withby means of efficient combustion techniques and gas purification, thanin the concentrated form resulting from re-refining.

There are several methods for re-refining, and these have to be evalua-ted on a case-by-case basis (compare Life-cycle analysis, section 4.4).Here we might note that purification on site, will probably always bethe preferred method from an ecological point of view.

Nynas always uses virgin oils, in order to avoid system contaminationwith additives (for example PCB) and to ensure full control of the rawmaterials from which our oils are manufactured.

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2 CLASSIFICATION AND ASSESSMENT

Classification and assessment cover only one aspect of the risk involvedin handling a chemical (n.b. an oil is considered a chemical by classifica-tion bodies). The other is exposure, i.e. if there is no exposure to a toxicchemical, then use of that chemical does not entail any risk.

In all cases, however, it is recommended to minimise exposure to anychemical. Special care is needed when handling used chemicals.

The classifications are based on pure chemicals (substances) and blendsof substances (preparations).

2.1 CHEMICAL SUBSTANCES PRODUCT STREAMS

The basis for classification and assessment is to arrive at a clear defini-tion of the substance in question.

The European Inventory of Existing Commercial Substances(EINECS) is a register of chemical substances in the EU. The substanceslisted are defined by their CAS (Chemical Abstracts Service) numbers,an American descriptive reference system that includes a short descrip-tion of the substance.

Since the composition of an oil distillate is highly complex and refining can be varied - both in the choice of technique and the way inwhich the different stages of refining are performed - the content offinished oils is infinitely variable. It would therefore be out of the ques-tion to devise CAS numbers for all existing grades. Instead a number of process streams have to be defined on the basis of different refiningprocesses, and these are then treated as if they were chemical substances.

Every process stream is identified by a CAS number and anEINECS number. All oils can be referred to by one of these productcategories. The content of the individual oil has a composition withinthe limit values that defines the process stream to which it belongs.

In describing the effects of an oil on health and the environment,what we are really describing are the theoretically worst possible properties of the different CAS categories. If a product stream is notincluded in the CAS system, full testing of the substance is necessary.However, this is so expensive that new products are difficult to intro-duce. Evaluation of existing process streams both can and should becross-referenced in the literature, to minimise animal testing of existingproducts.

The European labelling of substances follows the Classification ofDangerous Substances Directive, 67/548/EEC. This directive has beenrevised several times, with seven amendments and 22 adaptations to

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technical progress, the eighteenth of which prescribes procedures forthe self-classification of products not yet listed in the directive.

The main principle is that the best possible information should begiven for a process stream flow. The directive devotes a separate page to each substance included, and for mineral oils, notas are used, e.g.concerning carcinogenicity and aspiration hazards. There are some substances to which these notas are inapplicable, and the directive hastherefore to be consulted for the CAS number of the product to be evaluated; if the product is not listed in the directive, the self-classifica-tion procedure has to be employed.

Nynas Naphthenics manufactures a wide variety of products. Thesecan be divided into four main groups, with defined CAS numbers. Twoof these are especially prominent, i.e. hydrotreated light naphthenic dis-tillate with a viscosity of less than 19 cSt, CAS number 64742-53-6, andhydrotreated heavy naphthenic distillate, CAS number 64742-52-5. SeeChemistry, section 5.1.

2.2 MIXTURES OF SUBSTANCESSome products are mixtures of two or more substances.

Products composed of two product streams, and thus defined as amixture of two substances, include the oil/bitumen blends used formanufacturing printing ink and rubber. Here the product consists of anoil with a certain CAS number and a bitumen grade with another CASnumber.

Assessment of these mixtures (preparations) is regulated by thePreparation Directive 88/79/EEC. If, for example, a carcinogenic sub-stance occurs in the mixture in concentrations exceeding 0.1 per cent,the entire mixture has to be labelled. As yet there are no such condi-tions for mixture concentrations with regard to ecotoxicity, but thesewill probably be included in coming adoptions to preparation directives.

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3 PRODUCT INFORMATIONIN SAFETY DATA SHEETS

All customers purchasing oils from Nynas receive Safety Data Sheets(SDS) indicating the properties and effects of the product concerningsafety, health and the environment.

The required information content of the sheet is based on the EECDirective on SDS (Commission Directive 91/155/EEC implementationof Article 10 in Directive 88/379/EEC). There is also an internationalstandard for product information sheets (ISO 11014-1:1994), based onthe EEC standard. National standards may contain other conditions.

The product information sheet contains 16 obligatory main head-ings (categories of information). Neither the ISO standard nor the EECDirective specify the order in which the headings are to come. Some ofthese main headings will be commented on below (e.g. DangerousProperties in section 3.3, Toxicological Information in 3.5 andEcotoxicological Information in 3.6) although the information suppliedunder these headings is very clearly defined, it is hard to understand if the definitions are not known.

The manufacturermust be able to presentempirical data to sup-port the informationsupplied in the materi-al safety data sheet. Inpractice, this is admi-nistered by variousindustrial organisa-tions. Within theEuropean petroleumindustry, test resultsare collected and disse-minated by CONCA-WE. Member compa-nies contribute newtest results when theyare needed. These arethen made available toall member companies.Nynas, together withall main member com-panies, have contribu-ted to the common testbank.

Figure 2: Front page of a typical safety datasheet.

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3.1 IDENTIFICATION OF THE SUBSTANCE/PREPARATIONThis heading in the SDS is followed by information concerning the des-ignation of the product, its manufacturer and an emergency telephonenumber. The organisation with this number has our SDS and can ans-wer specific questions in an emergency. The CAS number can be statedhere, but this is not obligatory. The SDS may be valid for a range ofproducts with the same CAS number.

3.2 COMPOSITIONThe substance or substances included in the product (see section 2.2,Mixtures of substances) are stated here. The CAS number is obligatory,and often the EEC number is given as well.

When several substances are used, their proportions are given, mostoften expressed as an interval. This is not in any way to be regarded asa recipe or specification. Instead a fairly wide interval is given, e.g. 40-60 per cent. From this one may conclude that the properties stated inall SDS apply to all products whose composition comes within thisinterval. The percentage is important when deciding whether the mix-ture has to be labelled. The Preparations Directive bases labelling onthe quantity of the various substances.

Classification, if any, and danger labelling are also to be indicatedunder this heading. No such particulars are given under this headingfor Nynas Naphthenic oils, because they are not classified as dangerousto the health.

3.3 DANGEROUS PROPERTIESThe main properties considered dangerous to the environment, healthand safety are stated under this heading, together with relevant classifi-cations.

3.4 PHYSICAL AND CHEMICAL PROPERTIESThe properties stated here refer to the compositions shown under theheading Composition. Thus the product in question may have a muchnarrower specification than is indicated here, but it cannot have proper-ties which fall outside these intervals. In other words, there is no singlespecification for this product.

3.5 TOXICOLOGICAL INFORMATIONThis section provides detailed information on all harmful effects tohealth and the environment. Where some types of health hazards areconcerned, e.g. carncinogenic, information must always be given, evenif there are no risks involved. For other risks, e.g. defatting, informa-tion of this kind can be omitted.

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This section falls into four parts: Acute toxicity: This is always given, with the effects of ingestion

and dermal contact. Local effects: These are always given, with the effects of inhalation,

ingestion, dermal contact and eye contact. Sensitisation: This can be omitted. Chronic toxicity or long-term effects: These can be omitted.

3.5.1 Acute toxicityAcute toxicity means toxicity during brief, occasional exposure.

Acute toxicity is measured in LD50, which stands for Lethal Dose50% and is given in mg/kg. In other words, the dose given in mg per kgbody weight is the dose which is lethal to 50 per cent of those receivingit. LD50 is followed by an indication of the experimental animal used(most often a rat or a rabbit) and whether the product was swallowedby the animals, e.g. LD50/oral/rat, was applied to their skin, e.g.LD50/dermal/rat or was inhaled by them, e.g. LD50/inhalation/rat.

Because the type of exposure is stated, e.g. dermal contact, this in-formation is likely to be confused with the information presented underthe heading Local effects. Acute toxicity always refers to lethal doses,whatever the type of exposure. The effect, in other words, is not local,even if the exposure is. Exposure classification doses are appended.

3.5.2 Oils and toxicityA typical LD50 value for a highly refined naphthenic oil is:LD50/oral/rat

Limits are set locally for each country, in units of mg/m3.The conditions normally refer to average exposure over a period of fiveeight-hour working days. Measurements have to be taken in workingconditions and must include both particles and fumes.

For oil products, the value depends mainly on local conditions atthe workplace. Important conditions include ventilation efficiency, ope-rating temperature versus boiling range of the product (choice of pro-duct) and how operating speed influences particle emission versus pro-duct viscosity.

The actual exposure of people working in an environment with acertain substance concentration in the air is then influenced by the pro-tective equipment used. In order to minimise fumes, oil with a higherboiling range can be used.

3.5.3 Local effectsThe local effects are stated for dermal contact, inhalation and eyecontact. Here, then, we are concerned, not with lethal doses but witheffects on the skin, the respiratory organs and the eyes. Usually it isalso stated here whether ingestion leads to nausea and vomiting.

A chemical substance can have different degrees of corrosive, irri-tant or delipidising effects on the tissues it comes into contact with.

Definitions of corrosive properties are based on tests on animal skinor on the predictability of effects on animal skin. Effects on otherorgans are presumed to be no less serious.

3.5.4 Skin-delipidisingA skin-delipidising substance does not really have any direct effect onthe skin, it only affects the fat which is secreted by normal skin, for-ming a protective layer. Substances which dissolve this fat, e.g. deter-gents, solvents and oils, leave the skin dry and unprotected, which cancause skin disorders. These can be rectified by regularly applying a skinlotion to the exposed area.

Over-frequent washing with detergents can also dry out the skinand, the detergent as such can cause an allergic reaction. A mild type ofsoap is recommended, and a neutral skin lotion should be placed closeto the basin. For exposure to oils in large quantities, oil-resistant glovesor barrier lotions should be used.

The use of skin lotion is especially important in dry, cold weather.Conditions of this kind tend to dry out the skin, causing it to crack.Anyone handling oils should be on their guard against redness or skin-cracking.

3.5.5 Oils and local effectsLight oils, and especially light naphthenic oils, are widely supposed tobe more irritating to the skin than others. Nynas have therefore com-missioned an independent institute to test different base oils naph-

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thenic and paraffinic, light and heavier (see the chapter headed Skinirritation tests, section 4.1), to establish their dermatological properties.

The results show that neither naphthenic nor paraffinic oils can beclassed as primarily skin irritant. The majority are classed as slightlyirritant, while some are classed as non-irritant. Naphthenic oils areno more irritant than paraffinic.

3.5.6 SensitisationSensitisation means that an individual repeatedly exposed to a certainchemical substance becomes hypersensitive to it. The immune systemhas learned to recognise the substance and in future will be mobilisedwhenever the individual comes into contact with it.

This means that a substance which, for non-sensitised individuals, isneither toxic nor irritant, produces severe inflammatory reactions in thesensitised or allergic individual. This is what distinguishes allergenic orsensitising substances from irritant ones. A substance classed as irritanttriggers reactions at the very first time of exposure, while a sensitisingsubstance only does so when the individual has become hypersensitiveto it.

Some natural products that are used, for example as solvents fromnatural sources, have been shown to give allergic reactions.

Chemical substances can have sensitising effects in connection withtwo types of exposure: inhalation and dermal contact.

3.5.7 Oils and sensitisationThere are no studies to suggest that oils can cause sensitisation.

3.6 CHRONIC TOXICITY/LONG-TERM EFFECTSThe properties of chemical substances causing long-term effects in manare divided into three types: mutagenic, carcinogenic and teratogenic.

All three types are concerned with damage to human genetic materi-al. The differences between them concern the demonstrable effects ofsuch damage.

3.6.1 MutagenicityIf a substance is mutagenic, this means that exposure to it can lead tochanges - mutations - in the genetic code. This is a very general defini-tion; it does not say which organism can develop these mutations, nordoes it say anything about the consequences of the mutations for theorganism. What is tested, in other words, is the capacity to affect DNAmolecules. The fact that a substance is mutagenic does not mean thatthe mutations it may cause can in turn lead to cancer, impaired repro-ductive capacity or any other risk.

Mutagenicity, as a criterion of the harmfulness of a substance, suf-fers from the obvious disadvantage that there is no absolute connection

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between mutagenicity and, for example, carcinogenicity. The advantageis that there is a simple, dependable method for testing a substance formutagenicity, namely the Ames test (see section 4.3). This test requiresonly bacteria, not experimental animals, and it is both quick and rela-tively cheap.

Although the accepted way of testing a substance for mutagenicityis to test it on bacteria, in the labelling context mutagenicity is designedas the capacity of the chemical substance to cause hereditary geneticinjuries in human beings or increasing their incidence, the reason beingthat this, and not what happens to bacteria, is the interesting question.

Hereditary genetic injuries can occur through mutations in genecells. A mutation occurring in a sperm or ovum can lead to defects inthe progeny. This, then, is a specific consequence of a substance's muta-genicity. But it is a very serious consequence. If there is evidence that achemical substance can cause this kind of injury, this means that thesubstance is very dangerous.

For labelling purposes, mutagenicity is divided into three categories:

Category 1 There is enough evidence to establish a causal connec-tion between exposure to the substance and hereditary genetic injuries in man.

Category 2 There are sufficiently strong reasons for presuming a causal connection between exposure to the substance and hereditary genetic injuries in man.

Category 3 There is evidence from relevant mutagenicity studies, but not sufficient to place the substance in category 2.

In order for a substance to be placed in category 1, there should be epi-demiological studies showing, among persons exposed to the substance,an increased number of hereditary genetic injuries compared with thenormal population. Placement in category 2 calls for animal studies or other relevant information. Both these categories mean that the substance is labelled with a skull and crossbones as toxic. Substances in category 3 are regarded as harmful to health and labelled with the cross of St. Andrew. These substances may, for example, have shownmutagenicity in the Ames test but not in animal experiments.

If a substance is to be tested for mutagenicity and there are no pre-vious data concerning its effect on genetic material, the Ames testmakes an appropriate beginning.

3.6.2 CarcinogenicityAnimal experiments or epidemiological studies are generally used inorder to establish whether a substance is carcinogenic. Epidemiologicalstudies are very expensive and can only provide firm information aboutsubstances which many people have already been exposed to for a longtime, because often human beings do not develop cancer until severaldecades after exposure to the carcinogenic substance.

Animal experiments too are expensive and time-consuming, butthey are performed quite often in order to investigate whether a sub-stance is carcinogenic or not.

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The most common way in which a chemical substance can provokecancer is by causing a mutation in a special part of the human geneticmaterial, known as an oncogene. An oncogenic mutation in a cell,however, will not of itself lead to the formation of a tumour. Whetheror not this happens, will depend on a host of different factors, amongthem the efficiency of the body's immune system. Some chemical substances, although not themselves mutagenic, augment the risk of amutated oncogene leading to cancer. Substances like this are calledcancer promoters.

The mechanisms involved in the origins of cancer are complex andnot all factors are known, and so one cannot automatically infer that amutagenic substance is also carcinogenic or that only mutagenic sub-stances can be carcinogenic. The two properties have to be separatelytested.

3.6.3 TeratogenicityA chemical substance is defined as teratogenic if it impairs male or femalefertility or is capable of causing injury to the unborn child/progeny.

It is tempting to suppose that effects on human reproduction areconnected with damage to the genetic material. This is of course a pos-sible cause, but there are others. For example, a substance may affectthe hormonal balance and affect fertility in this way. Gestation too canbe disrupted by various chemical substances, without any mutagenicchanges being involved.

Teratogenic substances are divided into three categories, each ofwhich has two different definitions: one for effects on human fertility,and one for effects on the unborn child.

3.7 OILS AND LONG-TERM EFFECTSBecause mineral oils contain a very large number of chemical substances,assessments of different injury risks have to be based on tests of thewhole oil, not on each of the constituent chemical substances individu-ally. In this way it can be established that a highly refined naphthenicoil is neither mutagenic, carcinogenic nor teratogenic. This is because,after extreme refining, very little remains of the substances which areknown to be mutagenic and also carcinogenic, namely the polyaromates.

There are several ways of analysing the polyaromatic content (PAC)of an oil.

IP 346 (see section 5.2.1) is the method used for determining whetheran oil has to be labelled. This method supplies relevant informationabout the oil, because good correlation has been found between PAC as per IP 346 and mutagenicity and carcinogenicity. On the other hand, IP 346 does not provide a good quantitative indication of PAC.

According to IP 346, labelling becomes obligatory at 3 per cent. Ifthis were the real PAC, an oil with a value just below the limit wouldpresumably be clearly carcinogenic. The problem is that IP 346 doesnot measure PAC directly, but measures the proportion of the oilending up in the DMSO phase in an extraction. Analysing the DMSO

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phase, one finds that, in addition to polyaromates, it also includesmonoaromates and naphthenes. The true PAC content at a IP 346 valueof 3 per cent is approximately 0.1 per cent.

The graph above illustrates the difference between different oils andclearly shows that naphthenic oils at 3% IP 346 level are not carcino-genic. The data has been supplied by CONCAWE database and arebased on skin painting on mice. Four, five or more tumours on themice indicate that the oil is potentially carcinogenic. The percentage ofskin tumours is correlated to the IP 346. Other markers, such asBenzo(a) pyren, have not shown this correlation with skin tumours,hence the EU's decision to use IP 346 as a marker for labelling. It mustbe pointed out that oils that are not included, such as re-refined oils,used oils and blends of different substances can give misleading results.

Nynas oils have IP 346 values below 3%, and our oils have alsobeen tested by other methods, such as modified Ames tests, with goodresults.

The above graph also shows that low-refined oils such as distillatesand aromatic extracts, which have a high PAC content according to IP346, are carcinogenic to mice and therefore have to be labelled with askull and crossbones.

0 1 2 3 4 5 6 7 8

Paraffinic Naphtenic

% mice tumours

40

35

30

25

20

15

10

5

0IP 346

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Figure 3. Skin tumours versus IP 346.

3.8 ECOLOGICAL INFORMATION

3.8.1 MobilityThe mobility of a substance is usually determined by its solubility inwater. This information is mainly of interest in relation to the toxicityof the substance, but also in relation to its degradability.

A substance which is highly mobile in the environment can, forexample, enter the groundwater, which is serious if it is toxic. A sub-stance which is slightly toxic but mobile and at the same time readilydegradable will quickly be diluted and therefore less dangerous.

3.8.2 Persistence/degradabilityIt is always beneficial for the environment if a substance is biodegradable(see section 4.2). At the same time, this property is mainly interesting inrelation to toxicity.

A substance which does not degrade readily and, moreover, is toxic,is much more harmful than one which is persistent but non-toxic. Poly-aromates are both persistent and toxic, whereas naphthenes are muchmore degradable and are also non-toxic.

3.8.3 BioaccumulationBioaccumulation means that the concentration of a substance in livingbeings may increase with the passing of time. DDT and PCB are famili-ar examples. A substance bioaccumulates because it dissolves muchmore easily in fat than in water, with the result that it accumulates inthe fatty tissue of human beings and animals instead of being absorbedby the blood and disposed of by the liver and kidneys.

Bioaccumulation is measured in log Pow (the logarithm of the dis-tribution constant between octanol and water). A high value indicates arisk of bioaccumulation.

Substances found in mineral oils have a relatively high log Powvalue of 3.9 to more than 6. Whether or not this matters depends onwhether or not the substances are toxic, i.e. basically the decision canbe made according to their PAC value.

3.8.4 EcotoxicityEcotoxicity is measured and defined in essentially the same way asother toxicity, but instead of being based on facts about acute toxicityor long-term effects on man, it is concerned with effects on aquaticorganisms, soil organisms, flora and land animals.

Other effects on the environment can also come under the headingof ecotoxicity, e.g. effects on the ozone layer, potential for formingground-level ozone, potential for contributing to the greenhouse effectand effects on wastewater processing plants.

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In the case of mineral oils, there is a clear relation between PAC andecotoxicity. Oils with high amounts of PAC such as aromatic extractsshould therefore be labelled with R53/R52.

The ecotoxicity which is measured is mainly related to effects on aquatic life. Studies have shown that well-refined naphthenic oils donot have any toxic properties capable of posing a long-term threat toaquatic organisms. This is based on daphnia and fish studies. With refe-rence to the above, the following text is included in our data sheets(highly refined oils).

Aquatic toxicity data on base oils indicate an LC 50 value exceeding1,000 mg/l. Substances may not meet the criteria for ready biodegrad-ability and components have log Pow values ranging from 3.9 to greaterthan 6. However, chronic toxicity studies show that they do not repre-sent a long-term danger to the aquatic environment. No classification istherefore needed.

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4 METHODS, TESTS ANDORGANISATIONS

In this chapter we describe tests conducted and the results obtained. Wealso describe a number of organisations, such as CONCAWE and EUDGXI.

4.1 SKIN IRRITATION TESTSNynas commissioned Hazleton Laboratories Ltd., an independentinstitute in the UK, to test 17 base oils, partly to decide whether theyare skin irritants, but also to see whether there are differences betweennaphthenic and paraffinic oils and between oils of differing viscosity.

4.1.1 MethodThe test, which conformed to OECD Guidelines 404, was performedon rabbits. Oil was applied to the shaved test area on the rabbits backs,which was then kept under cover for four hours. When the oil hadbeen washed away, the skin was studied after 1, 24, 48 and 72 hours.The occurrence of inflammation and swelling was noted and was ratedon a 4-point scale. The sum total of the scores from 24 and 72 hours for all (12) animals were worked out and then divided by 6, to give anirritation index ranging from 0 to 16.

This means, for example, that an average of 1 for the degree of irri-tation after both 24 and 72 hours gives an irritation index of 4. An irri-tation index below 2 means that grade 1 effect was noted in not morethan half the observations.

Irritation index Classification0 non-irritating0-2 slightly irritating2-5 moderately irritating5 severely irritating

4.1.2 Results

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Sample Visc Irritation cSt/40C index

Paraffinic oil 2.5 028 1.290 1.2

Low refined 8 0.2naphthenic 22 1.3oil 100 0.5

Sample Visc Irritation cSt/40C index

Solvent refined 2.5 0naphtenic oil 8 0.3

22 1.0100 0.2

Hydrotreated 8 0.2naphthenic 22 1.3oil 100 0.5

In order for a substance to be classified as a skin irritant, significantirritation must occur and persist for at least 24 hours after an exposuretime of not more than four hours in tests on animal skin.

All the oils tested come outside this definition. There is no observ-able difference between naphthenic and paraffinic oils, nor can light oilsbe termed more irritating to the skin than heavy ones. On the otherhand one finds that both lighter and heavier oils are less irritating thanthose with a viscosity of about 20 cSt/40 C, the values for which areslightly higher in the case of both naphthenic and paraffinic oils.

4.2 BIODEGRADABILITYOne of the most important environmental properties of a chemical sub-stance is whether it is biologically or chemically degradable or stable. A toxic substance which breaks down rapidly in the environment gene-rally causes less environmental problems than a less harmful substancewhich accumulates in the environment. DDT, PCB and CFC are typi-cal examples of substances whose greatest fault is their stability.

Most, but not all, organic substances can be broken down byvarious microorganisms. Even substances which are toxic to humanscan serve as food for bacteria and fungi, for example. Some bacteria canadjust to using the most varied substances as carbon and energy sour-ces.

Stability, of course, is also a positive property in a substance. Itwould not exactly be an advantage if oil were to turn rancid in storage,perhaps necessitating the addition of preservatives in order for it toretain the properties conferred by refining. The preservatives couldthen cause more harm than the oil itself. The use of oils in some emul-sions has in fact proved conducive to health problems, as a result ofbacterial growth in the emulsions.

It is a fact that large quantities of oil are, for various reasons, releasedinto the environment. The harm the oil can do there depends on:

the amount of oil per unit of area the type of environment contaminated the composition of the oil.

4.2.1 Marine discharges of crude oilMost often when oil is mentioned as an environmental problem, thereference is to heavy discharges or escapes of oil at sea. In such cases,the acute damage is great, even though most of the oil can eventually bedegraded. Degradability is still worth studying, in order to find outwhether the oil released will persist in the environment for a long timeto come. Also, there are various ways of accelerating biodegradationwhen the mechanisms are known.

Some environments are more sensitive than others to the acuteeffects of oil discharges. Biodegradability also varies from one environ-ment to another. These differences depend mainly on the needs of theso-called oil-eating bacteria.

17

First and foremost, the bacteria need to be able to get at the oil.Because the bacteria need water, they can only get at the surface layerof the oil if it is sufficiently large. This is why emulsifiers are sometimesspread after an oil escape, so as to divide up the oil into small dropletswhich will have a large interface with the water. The problem with thismethod is that the emulsifier may be ecotoxic.

Once the bacteria have reached the oil, they need oxygen and othernutrients. At sea, oxygenation is usually so good that oxygen supply isnot a limiting factor. Sheltered bays with stagnant water are an excep-tion to this rule. On the other hand, there may be a shortage of nitro-gen and sulphur, for example. In connection with the tanker disaster offthe coast of Alaska in 1989, the expedient was tried for the first time ofspreading various fertilisers to boost the growth of the oil eaters.

It can take time for a strain of bacteria to develop which is adaptedto living on the escaped oil, and so sometimes an attempt is made tospread bacteria which are already adapted in this way. Grafting oileaters can be difficult, because the bacteria have to come from outsideand compete in an alien ecosystem, albeit an ecosystem containing thevery food they are adapted to. Grafting of this kind produces goodresults in laboratory experiments, but is usually less successful in natur-al conditions. In environments which are constantly being subjected tosmall escapes of oil, the bacteria population consists to a very greatextent of oil eaters, in which case biodegradation will be faster andmore efficient than in environments where escapes have not occurredpreviously.

4.2.2 Oil escapes on shoreWhen oil gets into the ground, the oxygen supply can vary a great deal,depending on the type of soil and moisture conditions. After an escapeof oil on land, the soil can be ventilated in various ways to improve thesupply of oxygen, e.g. by sucking in air with a vacuum pump dug intothe ground. A simpler way is to plough the soil. Oxygen can also beadded indirectly, e.g. by spreading hydrogen peroxide. This is anexpensive method and requires careful dosages. Excessive dosage harmsbacteria and under-dosage has little effect. Spreading nitrates which aredenitrified in the soil can also be an effective method, but it may causeproblems if the nitrates leach into the groundwater.

There may also be a shortage of various nutrients in the soil, and thespreading of fertilisers may hasten the degradation process.

4.2.3 Refined oilsAlthough the big tanker accidents are responsible for the most specta-cular escapes of oil into the seas, they do not by any means account forthe greater part of escapes. Used industrial oils and motor oils accountfor 63 per cent of discharges into the seas, whereas tanker accidentsaccount for only 2 per cent. There are no figures showing the quantitiesof these types of oil which end up in the soil.

18

Generally speaking, the simpler the molecules, the faster the biodegra-dation. Molecules with double bonding, aromatic rings and hetero-atoms degrade more slowly. The more complex the molecule, the harderit is to break down.

Alkanes, i.e. paraffins and naphthenes, are the hydrocarbons whichare most easily degraded by bacteria. Paraffins degrade somewhat moreeasily than naphthenes, straight paraffins more easily than branchedones, and naphthenes with few rings more easily than naphthenes withmany rings.

Aromates are more difficult for bacteria to break down. The smallerthe number of aromatic rings, the faster the biodegradation. Benzene isthe most readily degradable of the aromates, while polyaromates can bevery persistent.

Bitumens, i.e. asphaltenes and resins consisting of molecules withmore than eight aromatic rings, degrade very slowly. Extrapolation ofresults from experiments indicates between 25 and 75 per cent biode-gradation in 1,000 years. The molecules in bitumen form lumps of tarand stable emulsions which are not toxic but will remain present in theseas for a very long time. These substances are present in crude oil butseldom in refined products.

The polyaromates occupy a special position in the above list. Thesesubstances are both the most persistent and the most toxic. Asphaltenesand resins are the only substances which degrade even more slowly, butthey are not toxic. There is reason, therefore, to be extra vigilant withoils containing large quantities of polyaromates. From an environmentalviewpoint, it makes no difference whether the oil used is paraffinic ornaphthenic, because neither paraffins nor naphthenes are toxic, andboth paraffins and naphthenes are readily degradable. Environmentally,it is PAC that matters most.

4.3 THE AMES TESTThe Ames test has been accepted by some companies and organisationsas a marker for predicting carcinogenicity. Some scepticism persistsconcerning this method, but it is cheap and relatively fast. It has theadvantage of being a routine test and commercially available. Skin test-ing remains the ultimate method accepted as final evaluation, but testsof this kind are expensive and take about two years to perform. Ageneral effort is, however, being made to substitute short-term tests forpainful tests on animals. The method is based on the fact that mutated,histidine-dependent salmonella bacteria mutate back to histidine-inde-pendent when exposed to a mutagenic substance and the colonies startto grow.

Ames testing was adapted to petroleum products by Mobil, whohave found a correlation to skin painting on mice. Most sample prepa-rations for Ames tests are diluted with cyclohexane and extracted withDMSO to obtain an aromatic fraction from the oil. Liver homogenatefrom hamster and salmonella bacteria, commonly strain T98, are usedfor measuring frame test mutation. They are added to agar plates and

19

the colonies counted after 48h. The number of colonies is proportionalto mutagenicity.

A mutagenicity index is calculated from these results, and an MI ofmore than one is considered mutagenic.

Figure 4. The figure above shows two curves: one for a non-mutagenicproduct and one for a positive control oil mutagenic.

4.4 LIFE-CYCLE ANALYSISA life-cycle (LCA) analysis is an analysis of a system's environmentalimpact throughout its life-cycle. Note that the reference here is to asystem, not to a product. In order to mean anything, a LCA must referto a system performing a certain function. For example, one studies,not a litre of process oil for rubber production but the amount ofoil needed to achieve a certain plasticising effect in a certain amount ofrubber.

A LCA, in order to be meaningful, should involve some kind ofcomparison, perhaps a comparison between two different systems orbetween different parts of one and the same system. For purposes ofcomparison, one would like to be able to convert the different parts ofa complete LCA into figures which could then be added up. Thiswould give two numerical values, one of which would be incontestablyhigher than the other, thus showing one product or system to have amore negative environmental impact than the other.To arrive at numerical values of this kind, we have to evaluate differenttypes of environmental impact, which in turn calls for a valuation sys-tem. There ought preferably to be just one, universally accepted valua-tion system. Eventually there will presumably be a standard which isuniversally valid, but at present we have a host of different valuationsystems.

Nynas have not decided in favour of any particular valuation method,but one of our products on the other hand has been analysed and evalu-ated by ABB Transformers, using the Swedish EPS system, in whichenvironmental impact is calculated in terms of ELUs (Environmental

125

100

75

50

25

00 10 20 30 40 50 60

l of Extract per Plate

TA98 Revertants per Plate

275

250

225

200

175

150

125

100

75

50

25

0 0 10 20 30 40 50 60

l of Extract per Plate

TA98 Revertants per Plate

300

20

Load Units). If a customer wishes to work out the score for a Nynasproduct under some other valuation system, Nynas will supply all thedata required.

Valuation in the Swedish EPS (Environmental Priority Strategies inproduct design) system is based on how much people in the OECDcountries are prepared to pay in order to preserve a number of qualitiesof the environment, such as biodiversity, human health, the productivecapacity of ecosystems, and so on. Willingness to pay may sound like asubjective starting point, but it is in the nature of things that, as soon aswe depart from straight collection of data and begin to evaluate theimportance of the data, a certain subjective element creeps in.

4.4.1 ELU value of Nynas oilAt the time when ABB Transformers performed their life-cycle analysisof a transformer oil from Nynas, not all data from crude oil productionin Venezuela were available, and so use has been made of the valuewhich North Sea oil would have yielded, namely 0.458 ELU/kg.

Transport to the Nynshamn refinery contributes 0.0024 ELU/kg.Transport of the finished product naturally makes contributions ofvarious sizes, depending on where the customer is, but seldom contri-butes more than the crude oil transport.

Refining involves the use of electrical energy, roughly half of whichin Sweden comes from nuclear power and half from hydro power. Inaddition, fuel oil is used for heating. Energy consumption contributes atotal of 0.0305 ELU/kg.

All Nynas speciality oils undergo hydrotreatment. This requireshydrogen, which is produced from naphtha and water. Hydrogen pro-duction makes the biggest single contribution to the ELU/kg of the oil in refining, partly because naphtha and energy are consumed and carbondioxide is formed. Naphtha consumption in itself contributes 0.0358ELU/kg. This, however, is not to say that hydrotreatment is environ-mentally a bad method. On the contrary. The alternative would be sol-vent refining, which would reduce the naphtha requirement, but wouldinstead mean a lower yield and as a by-product would generate exotoxicwaste. To remove sulphur in the process would increase the ELU index,but on the other hand, using the oil after use as a source for energy wouldlower the amount of SO2 emission compared to traditional heavy fueloils. In addition to the product itself, hydrotreatment yields by-products:naphtha and sulphur. The naphtha can be used for hydrogen production.Altogether, refining leads to emissions of carbon dioxide, carbon mon-oxide, sulphur oxides, nitrogen oxides, hydrocarbons and dust. Allthese emissions taken together, however, make a contribution of 0.0660ELU/kg.

21

Figure 5. The figure above shows the life cycle of a base oil/transformeroil. It shows that, after use, the oil can be used as an energy source.Nynas produces Bitumen and Naphthenic oils only and has only a smalloutput of fuel.

ELU/kg oilRaw materials (mostly oil and naphtha) 0.50267Electricity 0.00065Non-electrical energy 0.02985Atmospheric emission 0.06599Effluent 0.00000025Waste 0.0124Total 0.60039

The total, then, comes to 0.6 ELU/kg oil, a figure which only becomesinteresting when viewed in relation to the value for other products, i.e. alternative products for the same function and products with otherfunctions relating to the end product.

A transformer manufacturer may find it interesting, for example,that the oil has a very low ELU value compared with other materials.The value for copper, for example, is 28.7 ELU/kg.

The quantity of crude oil used is estimated to account for nearly 80per cent of the total ELU value. This is because the Nynas refinery hassmall emissions and also because the use of crude oil is rated highlyunder the EPS system. This means that measures to improve the refin-ing yield, do a great deal to give transformer oil a low ELU value.Hydrotreatment refining gives a yield of about 0.8, whereas solventrefining gives about 0.5.

Using a life-cycle analysis for marketing is hazardous. It presupposesthat the result of the analysis can be generalised so as to apply to all

22

Rerefinings

Application

RefiningEnergy, raw materialEmission

Energy, raw materialEmission

Waste

Losses duringapplication

3%Bitumen

96%Fuel

Crude oil

Shipping

Refinery

Collection used oil

1% Base oil

functions which a product can perform. One interesting application,however, may be that of comparisons between subcontractors' environ-mental impacts. Perhaps one's own environmental impact can be reducedby changing suppliers.

The strategy is in its infancy and methods are gradually being refined.

4.5 ORGANISATIONS ANDAUTHORITIESBelow we present some of the bodies that exercise an important influ-ence on the formulation of Nynas policy.

4.5.1 CONCAWECONCAWE is the European organisation of the petroleum companiesfor the environment, health and safety. The emphasis of its work is ontechnical and economic studies of the refining, distribution and market-ing of oil in Europe. CONCAWE was formed in 1963 and its secretar-iat has been located in Brussels, Belgium since 1990.

Work within CONCAWE is divided between eight ManagementGroups: Air Quality Automotive Emissions Health Oil Pipelines Petroleum Products Safety Water Quality Refining Planning

The compilation of reports of different kinds is an important part of CONCAWE's work. These reports contain the results of scientificstudies performed by experts in various working groups. The reportsare distinguished by their dependability, and they supply technical andeconomic information to companies and authorities concerned with theenvironment, health and safety. A very large part of the data used bymember companies in their safety data sheets has been compiled byCONCAWE working groups.

There are various types of reports with various types of content,indicated by the cover design. Yellow reports deal with matters of gen-eral interest, blue reports are product dossiers, reports in A5 formatare known as field guides and the white reports deal with matters ofspecial interest to different groups.

CONCAWE also arranges seminars, often resulting in reports, onimportant subjects.Because the content of CONCAWE's reports is becoming increasinglycomplex and is of a high scientific standard, the organisation has alsobegun disseminating its results in more readable form by publishing theCONCAWE Review. For more information see: http://www.concawe.be

23

4.5.2 Directorate General XI (DGXI)DGXI is the European Union Directorate for Environment, NuclearSafety and Civil Protection. Its tasks are as follows: Determining and managing standards and criteria for environmental

quality and environmental space Addressing target groups with tasks and visions for solutions Developing and managing legal, economic, financial and social

instruments Promoting the application of policy instruments, environmental

infrastructure and appropriate implementation conditions Enforcement, monitoring and evaluation of the implementation of

EU policies and regulations.

DGXI is divided into five Directorates, of which Directorate E is espe-cially interesting to industry. Directorate E is responsible for the pro-motion and integration of environmental protection requirements intoindustrial, internal market and consumer policies; the co-ordination ofpolicies and activities in the field of environmental control of industrialinstallations and their emissions, industrial products and biotechnology,and waste management.

Directorate E covers the following areas: Industrial installations and emissions Industrial hazards, environmental management and eco-audit Chemical substances and biotechnology Waste management Industry, internal market, products and voluntary approaches.

The work of DGXI has been governed since 1993 by the Fifth Environmental Action Programme, the title of which, Towards Sustainability, underlines a concern with more long-term goals than previously, as well as a global perspective.

The following instruments are used in pursuit of the programme objectives: Legislation to set environmental standards Economic instruments to encourage the production and use of

environmentally-friendly products and processes Horizontal support measures (information, educations, research) Financial support measures (funds).

For more information see: http://www.europa.eu.int/en/comm/dg11 /dg11home.html

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5. APPENDIX

5.1 CHEMISTRYLabelling for each product group, e.g. CAS, is decided by the chemicalcomposition of each group. Under this section, different ways of char-acterising oil products will be discussed.

5.1.1 Chemical compositionThe naphthenic distillates used for Nynas' various product flows, allcome from the same kind of crude oil. This crude oil is distinguishedby high naphthene and aromate content, low paraffin content and alarge proportion of heavy molecules.

During distillation, the heavy molecules end up in the bitumen frac-tion. The lighter fractions are used for production of naphthenic baseoils, process oils and insulating oils.

The molecules in these fractions can be divided into three maingroups: paraffins naphthenes aromates.

The paraffins are straight hydrocarbon chains with varying numbersof carbon atoms.

The naphthenes are hydrocarbons containing one or more ringswith 5-6 carbon atoms each. There are no double bondings between thecarbon atoms in the rings. Paraffinic chains and aromate rings may bebonded to a naphthenic ring.

The aromates consist of one or more aromatic rings, i.e. hydrocar-bon rings with six carbon atoms and three double bondings betweenthem (the numbers of single and double bondings vary, and so the

25

Figure 6. Schematic molecule structures.

Paraffin Isoparaffin

Naphthenes

Aromatic Polyaromatic

molecule is usually drawn as a hexagon with a ring in the middle). Thearomates are divided into monoaromates (1 ring), diaromates (2 rings)and polyaromates (3 rings). In addition to aromatic rings, aromaticmolecules can also contain naphthenic rings, paraffinic chains and hetero-atoms. Hetero-atoms like sulphur and nitrogen are nearly 100 per centbonded to aromatic structures.

Complex structures with high molecular weight form part of thebitumen fraction.

5.2 METHODS OF PAC ANALYSISWhen discussing polyaromate content, one is very liable to find oneselfin a chalk-and-cheese situation. Measurements performed using methodslike IP 346, HPLC and GC give a very wide variety of results, becausethey measure completely different things, and so comparisons betweenresults are meaningless.

It is important to have a clear understanding about what the differ-ent methods measure and what it is one wishes to know.

5.2.1 IP 346IP 346 is the method used for deciding which oils have to be labelledunder EU regulations. The limit for labelling is three per cent byweight.

IP 346 measures the content of substances which are soluble indimethyl sulphate oxide (DMSO). DMSO is a polar organic solvent,and substances which are soluble in it have to be fairly polar. Theoccurrence of aromatic rings, naphthenic rings and so-called hetero-atoms (such as sulphur, nitrogen and oxygen) make organic moleculespolar. The more rings and/or hetero-atoms, the more polar the mole-cules become.

DMSO dissolves all polyaromates. Quite a number of single aroma-tes and naphthenes are also dissolved, especially if they contain hetero-atoms. As a result, IP 346 values are a good deal higher than true PAC,especially where naphthenic oils are concerned, naphthenes being agood deal more polar than paraffins.

Nynas' R&D department has studied the composition of the mole-cules extracted with DMSO from severe hydrotreated naphthenic oiland from an aromatic extract. With IP 346, severe hydrotreated naph-thenic oil scored 1.7 per cent and the aromatic extracts 30 per cent. Theanalysis was performed using HPLC (High Performance Liquid Chro-matography). The DMSO-soluble severe hydrotreated naphthenic oilfraction had a PAC of 5-10 per cent. The PAC of the DMSO-solublefraction from the aromatic extract proved to be between 20 and 50 percent. This means that a severely hydrotreated naphthenic oil had a PACof 0.1-0.2 per cent and the aromatic extract 6-15 per cent.

From these results one might jump to the conclusion that IP 346 isa bad method. First, though, we should discuss what it is we reallywant to know.

The main reason for wanting to measure PAC is that we want to

26

know whether the product may be carcinogenic. Results from IP 346analyses show good correlation with the occurrence of skin cancer inmice. The method, then, is relevant, even if it yields a percentage wellover the true PAC.

IP 346, in fact, does not purport to measure PAC, only to measurethe content of substances which are soluble in DMSO.

5.2.2 HPLCHPLC is one of the methods which Nynas uses in-house for measur-ing PAC. It is faster than IP 346 and does not involve handling DMSO,which is a very unpleasant chemical.

The Nynas HPLC method measures the quantity of substanceswhich are more polar than a given marker. The marker used is generallyeither naphthalene or anthracene.

With naphthalene which has two aromatic rings as a marker,severe hydrotreated naphthenic oil scores 1.7 per cent. An aromaticextract scores 30 per cent with the same marker. This measurementincludes molecules with at least two aromatic rings, the majority ofpolar diaromates and some monoaromates with hetero-atoms.

If instead we use anthracene (a three ring aromatic) as a marker, themajority of aromates with at least three rings and a number of mono-and di-aromates with hetero-atoms will be included. This time severehydrotreated naphthenic oil scores 0.17 per cent.

5.2.3 Gas chromatographyGas chromotography mass spectrophotometer (GC-MS) measures theconcentrations of individual substances. If, for example, we wish tomeasure the content of individual polyaromatic hydrocarbons (PAH)or to know the PAH profile of an oil, GC-MS is the best method.

Sometimes, however, one comes across studies in which a numberof polyaromatic hydrocarbons have been selected and their concentra-tions measured and added together. The sum total is then claimed toequal the total PAC. Often, only about 10 or so PAH has been meas-ured, whereas the oil analysed may actually contain several thousandpolycyclic aromates.

A Swedish firm of environmental consultants has performed a GC-MS analysis, using an ordinary standard method. Two Nynas oils andan aromatic extract were measured for their content of 15 PAH (seefigure 7). The test showed that the total content of the individual poly-aromates measured in severe hydrotreated naphthenic oil is less than 10ppm, while mildly hydrotreated naphthenic oil contains upwards of100 ppm and an aromatic extract about 850 ppm. In percentages thiscomes to 0.001, 0.01 and 0.085 respectively.

There is a big difference between the severe hydrotreated naphthe-nic oil scores of 0.001 per cent by GC-MS and 1.7 by IP 346, and alsobetween the extract's 0.085 per cent by GC and 30 per cent by IP 346.

If the total content of polyaromatic hydrocarbons is to be obtainedby adding the individual concentrations, then of course one has to add

27

the concentrations of all polyaromates in the sample. For severe hydro-treated naphthenic oil, more than 345 individual polyaromates havebeen identified. All one then sees is PAH. All substances with hetero-atoms have been removed by extraction prior to GC-MS analysis.

Once again, therefore, one has to ask: What is it we wish to know?If we want to know which oils may be carcinogenic, IP 346 will supplythe answer. If we wish to know the total PAC, there is no really exactmethod, but a good answer can be obtained using HPLC or a CG method which includes all polyaromates.

Figure 7. PAC ppm measured by GC-MS.

5.3 REFINING TECHNIQUEThere are several choices to be made when naphthenic crude is refinedto different grades. The technique chosen depends on a number of pre-conditions. Various environmental problems arise, some of them moreeasy or difficult than others to deal with, depending on the techniqueadopted.

5.3.1 The various stages of refining The first stage in refining is vacuum distillation, in which the oil is

divided into different fractions, depending on molecular boiling points.

After distillation the oil can pass through an extraction process to remove aromatic molecules.

Whether it has gone through extraction or not, the oil can be gentlyor severely hydrotreated.

28

PhenanthreneAnthraceneFluoranthenePyreneBenzo(a)fluoreneBenzo(a)anthraceneChrysene-TriphenyleneBenzo(j)fluorantheneBenzo(e)pyreneBenzo(a)pyrenePeryleneIndeno(1,2,3,cd)-PyreneBenzo(g,h,i)-PeryleneAnthatreneDibenzo(a,c) anthraceneIP 346

Severelyhydrotreated

5.3.2 DistillationThe first step in the refinery train is always distillation. In this processthe crude is separated into different boiling ranges by fractionation. Forlight crudes this is done under normal pressure. For heavy crudes orresidues the fractionation is performed under vacuum conditions.

Different viscosities are obtained for different oils with a given boil-ing range depending on their chemistry. The higher the boiling ranges,the more complex the structure that will be obtained. Gasoline, forexample, might contain benzene, which will not be found in heavierproducts such as lube oils. On the other hand, the complex PAC mole-cules will show up more isomers with increasing boiling ranges.

5.3.3 Solvent refiningIn solvent refining, the distillate is extracted with a polar solvent inorder to remove aromatic and polyaromatic compounds. Extractionresults in two phases, one with low aromatic content and one consis-ting almost entirely of aromatic compounds plus the extraction agent,normally furfural. The normal aromatic content obtained with solventextraction is between 5 and 11%. It is hard to achieve more or less thanthis, due to equilibrium between the phases. If higher aromatic contentis aimed for, the content of individual PAC will also increase.

The extract coming out of this process is of less value today, due to itshigh PAC content and because it is labelled with a skull and crossbonesboth for carcinogenicity and for ecotoxicity. Furthermore, the sulphurcontent is also high, which makes it of small worth for heating oils (SO2emissions).

29

Figure 8. Distillation process.

5 % %50 100 5 50 100

Temperature Temperature

The 5% point correlateswith the flashpoint

The 50% point correlateswith the viscosity

Dist.curve Bitumen

Crude

Figure 9. In the figure above, the extract emerging from the process possesses low commercial value due to the high content of sulphur andPAC.

5.3.4 HydrotreatmentHydrotreatment of the distillate involves adding hydrogen in the pre-sence of a catalyst at high temperature and high pressure. The hydrogenthen reacts with aromatic rings, causing the double bondings to breakand hydrogen atoms to take over the free bonding spaces. The bond-ings between hetero-atoms and hydrocarbons are also broken, with theresult that the hetero-atoms are replaced by hydrogen atoms. Hydroxylgroups also disappear, which leads to the disappearance of naphthenicacids, for example.

As a result, aromatic rings are converted into naphthenic rings andhetero-atoms are removed. The proportion of aromates and hetero-atoms reacting with the hydrogen depend on the process conditions.Higher pressures and temperatures together with more efficient cata-lysts will mean a larger proportion of the aromates reacting with thehydrogen.

Figure 10. Simplified hydrogenation process (where x=sulphur, nitrogen and oxygen).

In theory, hydrotreatment can be taken to any lengths, but in practice,of course, there are limits. Besides, excessively severe treatment wouldcause the naphthenic rings to disintegrate and paraffins to form, whichis undesirable if one plans to utilise the special properties of naphthenes,such as good solubility and good low temperature properties. If refin-

30

CA%D = Distillate 20-25R = Raffinate 5-12E = Extract >40

R

E

SolventSolvent

Oil

Mixing

Raffinate DistD

Extract

Dist

Light products, H2S, NH3, H2O

HIGH SEVERITY

MEDIUM SEVERITY

X

CA 25%feed

H2

H2

CA %20-25

CA %2-17

H H . H . H .

H . H . H . H .

H H. H .

H . H . H . H .H H .

H .X

X

X

CATALYST

CATALYST

ing is to be taken to extreme lengths, as for example in the productionof white oils, it may be preferred to extract first and hydrotreat theoil afterwards.

5.3.5 Acid clay treatmentSulphuric acid is the most versatile refining agent known. It acts as anextraction medium and as a reactive agent, depending on temperatureand concentration. Oleum is still used in some countries for productionof petroleum sulphonate, but is being successively replaced by hydro-treatment. Acid clay is an obsolete process today, due to labelling andthe ecotoxic waste which the process generates.

31

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Responsible CareNynas is a signatoriy to the international Responsible Care programme of the

CEFIC (European Chemical Industry Federation).

The programme is the chemical industrys commitment to continuous

improvement in all aspects of health, safety and environmental protection.

Responsible Care is a voluntary initiative, fundamental to the industrys

present and future performance and a key to regaining public confidence and

maintaining acceptability.

The signatories pledge that their companies will make health, safety and

environmental performance an integral part of overall business policy on all

levels within their organizations.

SALES OFFICES

Australia & New ZealandNynas (Australia) Pty Ltd. One Park Road, Milton, QLD 4064, Brisbane, Australia

Tel: +61 7 387 66 944. Fax: +61 7 387 66 480

BelgiumNynas N.V., Haven 281, Beliweg 22, BE-2030 Antwerp

Tel: +32 3 545 68 11. Fax: +32 3 541 36 01

BrazilNynas Do Brasil LTDA, Rua Jesuino Arruda 676, 9th Floor cj. 91, Itaim Bibi, So Paulo, SP

Tel: +55 11 3083-1399. Fax: +55 11 3082-2537

CanadaNynas Canada Inc., Suite 610, 201 City Centre Drive, Mississauga, Ontario, Canada L5B 2T4

Tel.: +1 905 804-8540. Fax: +1 905 804-8543

ChinaNynas (Hong Kong) Ltd. Beijing, Room 703C, Huapu International Plaza

No. 19 Chaoyangmenwai Street, Beijing, 100020Tel: +86-10-6599 26 95. Fax: +86-10-6599 26 94

France Nynas S.A., Le Windows, 19 Rue dEstienne dOrves, F-93500 Pantin

Tel: +33 1 48 91 69 38. Fax: +33 1 48 91 66 93

Germany Nynas GmbH, Berliner Allee 26, D-40212 Dsseldorf

Tel: +49 211 828 999 0. Fax: +49 211 828 999 99

Great BritainNynas Naphthenics Ltd, Wallis House, 76 North Street, Guildford, Surrey, GU1 4AW

Tel: +44 1483 50 69 53. Fax: +44 1483 50 69 54

Hong KongNynas (Hong Kong) Ltd, 1301 Chinachem Johnston Plaza, 178-186 Johnston Road, Wanchai

Tel: +852 2591 99 86. Fax: +852 2591 49 19.

ItalyNynas S.r.l., Via Teglio 9, I-20158 Milan

Tel: +39 02 607 01 87. Fax: +39 02 688 48 20

MalaysiaNynas HK Ltd, Representative office, Suite No 7, 22nd Floor, MNI Twins Tower 2

11 Jalan Pinang, 50 450 Kuala LumpurTel: +603 21 69 65 08. Fax: +603 21 69 64 09

PolandNyns Sp. z.o.o., ul. Toszecka 101, 44-100 Gliwice

Tel: +48 32 232 74 10. Fax: +48 32 279 28 50

South AfricaNynas South Africa (PTY) Ltd, Gatesview House A3, Constantia Park

Cnr 14th Avenue and Hendrik Potgieter Street Weltevreden ParkTel: +27 11 675 1774. Fax: + 27 11 675 1778

Spain Nynas Petrleo S.A., C/Serrano 45 - 7Dcha, E-28001 Madrid

Tel: +349 1 431 53 08. Fax: +349 1 575 49 12

SwedenNyns Naphthenics AB Norden, P.O. Box 10701, S-121 29 Stockholm

Tel: +46 8 602 12 00. Fax: +46 8 81 20 12

TurkeyNynas Naphthenics Yaglari Tic. Ltd. Sti. Kantaciriza Sokak 15/3, 81070 Erenky, Istanbul

Tel: +90 216 368 38 42. Fax: +90 216 368 37 48

Central- and Eastern Europe / Middle East / Latin AmericaNynas Naphthenics AB

Box 10701, S-121 29 Stockholm, Sweden. Tel + 46 8 602 12 00. Fax: + 46 8 508 665 10

RESEARCH & DEVELOPMENTNyns Naphthenics AB, S-149 82 Nynshamn, Sweden

Tel: +46 8 520 65 000. Fax: +46 8 520 20 743

Internet: www.nynas.com/naphthenics