lorena deleanu, sorin ciortan, liviu cătălin Şolea 2009... · the annals of university...

THE ANNALS OF UNIVERSITY “DUNĂREA DE JOS“ OF GALATI FASCICLE VIII, 2009 (XV), ISSN 1221-4590

TRIBOLOGY

124

Paper presented at the

International Conference on Diagnosis and Prediction in Mechanical

Engineering Systems (DIPRE’09) 22 - 23 October 2009, Galati, Romania

RAPESEED OIL FLAMMABILITY ON HOT SURFACE

Lorena DELEANU, Sorin CIORTAN, Liviu Cătălin ŞOLEA

University “Dunărea de Jos” Galati, ROMANIA [email protected]

ABSTRACT The paper presents the tests and results upon rapeseed oil flammability on hot surface. The oil samples were obtained from a rapeseed oil after a dewaxing process. There were established temperature ranges for which the oil samples could get one of the three qualifications, as expressed in SR EN ISO 20823:2004.

KEYWORDS: Rapeseed oil, flammability on hot surface, flammability test,

SR EN ISO 20823:2004.

1. INTRODUCTION

Romania is the 15th world producer of rapeseed. Analysing the UN Food & Agriculture Organisation statistics, among the first 20 countries producing rapeseed, there are 10 countries from the European

2007

0.000 2.000 4.000 6.000

DE

FR

PL

UK

CZ

DK

HU

RO

SK

SE

Rapeseed production (million tones)

Fig. 1. Rapeseed production of UE countries in the top 20 world producers [6]. ISO 3166-2 code

Alpha-2 symbols for countries’ names.

Union, their sum production being 17,137,511 tones (fig. 1) that is 86.5% of the production volume of the first two countries (China and Canada) and almost 34% of the world total [6].

These facts underline the increasing interest for producing and using rapeseed oils, not only for food, but also for industrial applications as lubricants and bio-fuels [7, 10, 16, 17]. Oil-seed crops (for example, rape-seed, soybean and sunflower) can be converted into methyl-esters, which can substitute normal fossil diesel, and they can be used in their pure or blended states [17]. The success of vegetal oils is related to their biodegradability and reduced toxicity, but a wide use is limited by a set of properties being of great interest for industrial applications, including their unsatisfactory stability in time [12, 15].

At present, the use of pure (non-altered) vegetal oils is limited only for applications with total loss of lubricants, such as chain saws lubricants, oils for moulds and hydraulic fluids, with a low level of ther-mal and mechanical stresses [10, 21]. The usage of fast biodegradable lubricants represents an ecological advantage, but also an economical one. Unfortu-nately, the presence on the market of these materials is relatively low. Figure 2 shows the total USA vegetal oil and animal fat consumption in 2007 [18]. A market study shows that the share of non-polluting hydraulic fluids, based on vegetal oils, increased in 2000 at 8% and the tendency is maintained [12].


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Fig. 2. Total US vegetal oil and animal fat

consumption (15.0 billion kg/year) by source (Bureau of Census, USDA-ERS) for 2007-2008.

Selecting a fluid for an application includes not

only high level of performances for the main aim (lu-bricant properties as viscosity and viscosity index etc. for tribosystems, thermal properties for processing and treatments, time stability properties under wor-king conditions in any application), but also the crite-ria of reducing fire risk as this characteristic becomes of major interest in particular and general industrial applications [1-54, 13, 22].

For industrial applications of vegetal oils their flammability characterisation is of recent interest as researches were conducted especially for improving their properties obviously required by the system: viscosity, time-temperature stability etc. The industrial oleochemicals business is investigating the use of high oleic vegetal oils in order to act as feedstock for the production of numerous products [7, 14, 21]. These products not only have the ecological benefit of being biodegradable and derived from a renewable resource, but they also have different and enlarged functiona-lities.

High oleic vegetal oil is being tested and utilized in the cosmetics business and as a machine lubricant (e.g., for high temperature engine, transmissions, hydraulics, gears and grease applications). Independent testing has shown that these new oils may actually perform better than petroleum-based products in some uses [12, 14, 21].

Longterm projections indicate that continued advancement in industrial applications research could result in an even greater volume requirement for high oleic oils in industrial applications than in edible applications [7].

Until recently, manufacturers have not had much choice. Synthetic alternatives to mineral oils, such as polyglycols and polyol esters, have been priced out of reach for most manufacturers. Those with high-pressure and other extreme applications requiring a fire-resistant hydraulic fluid have had to “bite the bullet” - paying up to six times more for synthetic hydraulic oils than they used to pay for petroleum-based products (fig. 3) [14].

To answer this need, many industrial oil produ-cers have began to formulate efficient hydraulic fluids based on vegetal oils. Because vegetal oil is a naturally occurring ester, it is biodegradable. It also exhibits good lubricity, on par with synthetic polyol ester fluids. In addition, vegetal oil is a relatively inexpensive base stock [14, 17].

These vegetal oils have traditionally exhibited low oxidative stability – a critical shortcoming, which prevented their widespread use [10]. However, resear-ches and tests are continued, working with additive packages and using selected base stocks, and creating fire-resistant fluids [14, 21]. For instance, Cosmolubric B-230 [14] is a canola1 oil-based and uses additive technology to successfully perform like polyol esters. It contains viscosity index modifiers, rust and oxidation inhibitors, extreme pressure (EP) additives, copper passivators and defoamers. These additives have improved the oxidation stability of vegetal oils, so that they can equal the desired characteristics of synthetic polyol esters.

0 2 4 6 8

Mineral oil

Invert emulsion

Water glycol

Canola oil

Synthetic polyol ester

Phosphate ester

Fig. 3. Cost comparison of hydraulic fluids base stocks [14].

Table 1. Cost comparison of hydraulic fluid

base stocks (adapted from [14]). Canola

oil Synthetic

polyol Mineral polyol

ISO viscosity grade 68 68 68 Viscosity [cSt]: at 100°C

14.3

12.5

8.3

at 40°C 75.1 68.3 74.0 Viscosity index 214 214 90…100 Acid number 0.9 3.0 0.8 Flash point, °C 257 312 196 Fire point, °C 321 615 218 Pour point, °C -18 -23 -15 Specific gravity 0.92 0.92 0.88

1 Rapeseed (Brassica napus), also known as rape, oilseed rape, rapa, rapaseed and (in the case of one particular group of cultivators) canola, is a bright yellow flowering member of the family Brassicaceae (mustard or cabbage family). The name derives from the Latin for turnip, rāpum or rāpa, and is first recorded in English at the end of the 14th century.


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Organizations such as Occupational Safety and Health Association (OSHA), National Fire Protection Association (NFPA) and some specialists classify flammable liquids according to their flashpoint [1, 4, 11, 22]. A flashpoint within the operating temperature range of the system is obviously undesirable as any leak would create an immediate fire hazard [1, 4, 14]. Thus, the aim of the paper is to give a qualifica-tion of this grade of rapeseed oil (the grade obtained after dewaxing process of the oil) concerning the flammability on hot surfaces.

In 2000 Koseki, Natsume and Iwata reported that the flash points of vegetal oils are above 300°C, which are considerably higher than those of fuel oils with flash points of 100°C and lubricating oils with flash points of 160…300°C, vegetal oils being considered relatively safer than hydrocarbon oils. However, it was found that the burning rate, radiant heat, and flame height of vegetable oils are higher than those of C-fuel oil or some of lubricating oils. This means that once a fire occurs, the fire propagation danger of vegetal oils is higher than C-fuel oil or some of lubricating oils [13].

2. TESTING METHODOLOGY

The standard EN ISO 20823:2003 “Petroleum and related products. Determination of the flammability characteristics of fluids in contact with hot surfaces. Manifold ignition test” was adopted in Romania in 2004, by the endorsement method and it gives a testing method for determining the relative flammability of a fluid when it contacts a hot metallic surface having a fixed temperature. The method also allows establishing the ignition temperature of the studied fluid by increasing the manifold temperature in steps. The test results are quantified in only three possible results: I(T) when the fluid flashes or burns on the tube, but does not continue to burn when collected in the tray below, I(D) when the fluid flashes or burns on the tube and continues to do so when collected in the tray below and N when the fluid does not flash or burn at any time. The procedure was well established in order to obtain repeatability, a much desired characteristic of test results, but hard to obtain for test involving fire or flammability characteristics. The equipment used in LubriTEST Laboratory at University “Dunarea de Jos” of Galati has this plat-form with three thermocouples as ISO standard recommends (position 7 in fig. 4) [5], but a better accuracy was obtained with a thermocouple attached to the manifold surface and protected by a small case made of the same steel as the manifold, welded as the thin bar required by the standard. Figure 5 presents the display of the PC included in the testing equipment in order to preserve the design requirements as established in the logical chart in figure 6. Points 1 and 2 (fig. 5) are confirmed by

Romanian Bureau of Legal Metrology (BRML) to fulfil the requirements of SR EN ISO 2003:84, meaning reaching a temperature of 700±5ºC, point 3 having a tolerance greater than ±5ºC, but not reaching ±6.0ºC); this is the reason why point 3 is used only for research purpose and for protecting the manifold not to have a thermally non-loaded zone. All results presented here are obtained for points 1 and 2 (fig. 5 and table 2).

Fig. 4. Frammability test Equipment: 1-dispenser monitoring system, 2-ventilated enclosure, 3-2D robotic arm, 4-fluid reservoir, 5-high temperature

steel sheet box, 6-hot manifold (with electric heater), 7-the thermocouples’ platform, 8-automatization

system, 9-video fast camera.

Fig. 5. View of the commanding display of the equipment computer.

The samples of rapeseed oil (obtained after a dewaxing process) were tested under the standard conditions (10 ml ± 1ml of tested fluid dropped on the hot manifold in 50 s±10 s, initial oil temperature: 20…25ºC, ambient temperature: 20…22ºC, air relative humidity: 58±12%). Table 2 presents the test results, in a chronological order, last column having some authors’ remarks about the fluid behaviour when dropping on the hot surface being maintained at different temperatures.


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CTTTT

T requestedCCC

m05

3321 ±=

++=

CTT cerutm05±> CTT requestedm

05±>

Fig. 6. Logical chart of the testing equipment [8, 9] as designed by professor Lorena Deleanu and put into

practice by ICTCM Bucharest, Dolsat SA and University “Dunarea de Jos” of Galati.


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128

3. RESULTS AND DISCUSSION Oil samples were obtained from ULVEX SA Ţăndărei, Romania and all tested samples were of rape-seed oil after a dewaxing process, from the same charge. Taking into account former papers and tests [8, 9], table 2 presents the behaviour of this vegetal oil grade, this one being separated into three classes, depending on the temperature range and the fluid behaviour: 1. a temperature range for which there are obtained repeatedly the same results when testing the fluid on hot manifold (200…551ºC); 2. a temperature range for which the test results are randomly different (in one test the fluid does not burn, but in the following one it is burning and so on): 551…557ºC; 3. The temperature range for which the fluid burns, receiving one of the two qualifications, depending on the burning process: θ > 560ºC. Analysing the recorded films of the tests the authors noticed the followings: • when tested at the highest temperature at which

the fluid does not burn, there was noticed white, foggy vapour due to the evaporation of some components of the oil, but liquid drops of fluid are still visiblely flowing on the hot manifold;

• there is a tendency of fluid to flash and/or burn on the tube and continues to do so when collected in the tray below (meaning the qualification I(D), as coded in the ISO standard), characterising the temperature range closely above 551ºC, that is

560…570ºC and not the highest range tempera-ture tested in the laboratory (600ºC);

• tested at 570…600ºC, the oil could get the quali-fication I(T), that is when the fluid flashes or burns on the tube but does not continue to burn when collected in the tray below.

Even if the dropping process was regulated before heating the manifold, meaning the oil volume to flow in small drops, with a quite constant rate during 40…60 seconds, as imposed by the test procedure in the ISO standard, the burning process was intermittent for almost all tests as one may notice from analyzing the photos presented in figures 7 to 10. This could be explained by the presence of many chemical constituents in this vegetal oil, and further study will be done for trying to explain this process. Taking into account the results, the temperature at which the tested oil does not burn anyway (551ºC) is similar to some previously tested additivated mineral oils for transmissions, including T90 (Rompetrol); this oil had obtained the qualification N for 545ºC, but from 550ºC it burns getting an I(D) qualification. Tests were repeated 6 times for each of these temperatures. As temperature allowances are ±5ºC, any test between this two values (545 and 550ºC) are irrelevant, especially because tests between these temperatures do not have repeatability for T90 (Rompetrol). The same conclusion could be underlined for the temperature range 552…562ºC for the dewaxed rapeseed oil.

Table 2. Results of testing dewaxed rapeseed oil flammability on hot surface.

Test no.

Temperature of the

manifold surface [ºC]

Dropping time [s]

Fluid qualification

Comments

1 200 57 N 2 250 45 N 3 300 49 N 4 350 40 N 5 400 56 N 6 450 45 N 7 500 43 N; very fine traces of white vapour (visible only on the film and under careful

observation of the manifold surface; also there are visible fluid drops sliding along the manifold and falling on the tray below.

8 551 39 N; (dropping time is 1 second shorter than the interval recommended by ISO standard procedure); white vapour, very visible, but with variable intensity of generation: there are also visible fluid drops sliding along the manifold and falling on the tray below (fig. 7).

9 600 42 I(T); fluid burns, the flames being continuous, but having variable height in time 10 574.6 38 I(D); (dropping time is 2 second shorter than the limit value recommended by

ISO standard procedure); test was repeated after tuning the dispenser (fig. 9). 11 575 45 I(D); the fluid burns intermittently. 12 577.2 I(D); the fluid burns intermittently (fig. 10) 13 562 59 I(T) (fig. 8).

Note: I(T) when the fluid flashes or burns on the tube but does not continue to burn when collected in the tray below, I(D) when the fluid flashes or burns on the tube and continues to do so when collected in the tray below and N when the fluid does not flash or burn at any time.


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6th second 14th second 43th second

Fig. 7. The rapeseed oil tested on the manifold having the temperature of 551ºC.

2nd second (first drop on

manifold, visible white fume, but the drop does not burn yet)

11th second (the oil does not burn yet, but there is visible fume, but

oil is changing its chemical structure and reaction substances remain on the manifold as dark

and non-uniform deposits).

20th second (this drop is burning on the tube and part of it continues to burn when falling, but does not

reach the tray in burning).

22nd second (detail of the burning

oil on the hot manifold). 58th second (the oil burns in the

tray). 59th second (last drop is

extinguishing on the manifold). Fig. 8. The rapeseed oil tested on the manifold surface heated at the temperature of 562.0ºC.

4. CONCLUSION

Prediction or diagnosis is connected by the future evolution of various processes occurring inside the complex technical systems with a view to optimizing their relevant parameters. Diagnosis implies a work for putting into a structure the cumulated knowledge. This structure must be based on the systems theory. The after-dewaxing rapeseed oil could be recommended as industrial fluid, not only as bases for lubricant formula, but also as industrial fluid for cutting processes or heat treatment, especially because it could be used in some of these applications as emulsions oil-in-water or water-in-oil. Of course, the first type could be less expensive, but design and

maintenance engineers have to pay attention to how the presence of water would affect machine elements and durability of the entire system, even if these solutions are environmentally friendly. The after-dewaxing rapeseed oil is only a product obtained after a necessary step in refining vegetal oils, but further processes of modifying this oil could give better results as concerning the flammability on hot surfaces or/and other desired properties. Studying how the oil is manifesting on hot surfaces could offer solutions for fire sensors and fire suppression in industrial, transport fields, but also for those used in public food service, evaluating better the fire risks in these domains of activity.


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1st second (first oil drop under the nozzle of dispensing device).

2nd second (first oil drop reached the hot manifold surface).

4th second

6th second 8th second

10th second

11th second 12th second

13th second

15th second 17th second 19th second

Fig. 9. The rapeseed oil tested on the surface manifold temperature of 574.6ºC.

Note. All images were extracted with the help of a specialized soft in order to observe the time recorded on the PC display.


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2nd second(first drop on manifold) 3rd second 4th second

5th second 6th second (second drop on

manifold). 7th second

Fig. 10. The rapeseed oil tested on the manifold surface heated at 577.2ºC (snapshots are chronologically extracted).

REFERENCES

1. ** Approval Standard for Flammability Classification of Industrial Fluids (Class 6930), Factory Mutual Global, January 2002. 2. ** Council Directive 92/104/EEC of 3.12.1992 on the mini-mum requirements for improving the safety and health protection of workers in surface and underground mineral-extracting industries (twelfth individual Directive within the meaning of Article 16 (1) of Directive 89/391/EEC) (OJ L 404, 31.12.1992), Amended by: Directive 2007/30/EC of the European Parliament and of the Council of 20.06.2007, L 165 21 27.6.2007 3. ** Directive 94/9/EC of the European Parliament and the Council of 23.03.1994, on the approximation of the laws of the Member States concerning equipment and protective systems intended for use in potentially explosive atmospheres, (OJ L100, 19.4.1994, 1), amended by Regulation (EC) No 1882/2003 of the European Parliament and of the Council of 29.09.2003, OJ L284 1 31.10.2003, Corrected by Corrigendum, OJ L21, 26.1.2000, 42 (94/9/EC), Corrigendum, OJ L304, 5.12.2000, 19 (94/9/EC). 4. ** HSE Approved specifications for fire resistance and hygiene of hydraulic fluids for use in machinery and equipment in mines, (M) File L11.6/3, (1999). 5. ** ISO/TC 28N 2139, 2001, Results of voting ISO/CD 20823 Petroleum and related products. Determination of the flammability characteristics of fluids in contact with hot surfaces. Manifold ignition test. 6. .** Food and Agriculture Organization of the United Nations, FAO Statistics Database, http://faostat.fao.org/, available on-line at the address: http://faostat.fao.org/site/339/default.aspx 7. Butzen S., Schnebly S., 2009, High Oleic Soybean, on-line: http://www.pioneer.com/web/site/portal/menuitem.666b80f644978322a0030d05d10093a0/#indus 8. Deleanu L. et al., 2007, Research Report for grant CEEX-M4-452 “Adoption and Implementation of Test Methods for Lubricant Con-formity Assessment” supported by National Authority for Scientific Research, Minister of Education and Research Romania. 9. Deleanu L. et al., 2007, Flammability Test Data in Risk Assess-ment, 10th International Conference on Tribology, Bucharest, Romania, paper RO-061, pp 2.2-6.

10. Fox N.J., Stachowiak G.W., 2007, Vegetable oil-based Lubricants. A review of oxidation, Tribology International, 40, pp. 1035-1046. 11. Jagger S.F. Nicol, A., Sawyer J., Thyer A.M., 2004, The incorporation of fire test data in a risk-based assessment of hydraulic fluid fire resistance, INTERFLAME, p. 569-576. 12. Karheinz H., 2000, Fats and oils as oleochemical raw materials, Pure Appl. Chem., vol. 72, no 7, pp. 1255-1264. 13. Koseki H., Natsume Y., Iwata Y., Evaluation of the Burning Characteristics of Vegetable Oils in Comparison with Fuel and Lubricating Oils, Journal of Fire Sciences, vol. 19, January/February 2001, pp 31-44. 14. Noblit T., 2005, Biodegradable Hydraulic Fluids Prove Bene-ficial - Fire Resistance a Plus, Machinery Lubrication Magazine, March 2005 15. Qingye Gong Q., He W., Weimin Liu W., 2003, The tribological behavior of thiophosphates as additives inrapeseed oil, Tribology International, 36, pp. 733-738. 16. Shunmugam V., 2009, Biofuels—Breaking the Myth of ‘Indestructible Energy’?, Journal of Applied Economic Research, vol. 3, no. 2, pp. 173-189. 17. Schneider M., Smith P., 2002., Plant Oil in Total Loss & Potentisl Loss Applications, Finall Report, Government Industry Forum on Non-food Uses of Crops (GIFNFG 7/7), 16 May. 18. Hayes, K.F. Skerlos S.J., 2006, Design of Novel Petroleum Free Metalworking Fluids, R831457, US. 19. Toy, N. Nenmeni, V.l., Bai X., Disimile P.J., 2004, Surface ignition on a heated horizontal flat plat, 4th Intern. Aircraft & Cabin Safety Research Conerence. 20. Yuan L., 2006, Ignition of hydraulic fluid sprays by open flame and hot surfaces, J. of Loss Prevention in Process Industry, vol.19 (4), pp. 353-361. 21. Zeng X., Wu H., Yi H., Ren T., 2007, Tribological behavior of three novel triazine derivatives as additives in rapeseed oil, Wear, 262, pp. 718-726. 22. Zinc M.D., 2000, Fire Resistant Hydraulic Fluids: Shifting Definitions and Standards, Proc. of 48th National Conf. on Fluid Power, paper 105-8.3.

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