UNIVERSITY OF ZAKHO

Faculty of Engineering

School of Petroleum Engineering

Practical Petroleum Properties Lab.

2nd Year Level

Name of student: Diar Ismail MohammedStage: 2nd stageClass: AName of Experiment: Determination of Flash and Fire Point by Cleveland open Cup Tester (for light fractions)

No. of Experiment: 5Experiment date: 10 .1.2016Date of submitting: 18 .1.2016

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Experiment No. 5

Determination of Flash and Fire Point by Cleveland open Cup Tester (for light fractions)

1. Objective:

To determine flash point of an oil product using open cup method (Cleveland open cup apparatus

2. Introduction:

This International Standard specifies a procedure for the determination of flash and fire points of petroleum products using the Cleveland open cup apparatus. It is applicable to petroleum products having an open cup flash point above 79 °C, except fuel oils, which are most commonly tested by the closed cup procedure.

Flash point and fire point are indications of the ability of a substance to form a flammable mixture with air under controlled conditions, and then to support combustion.

Flash Point: - Flash point of an oil is the lowest temperature at which the oilgives sufficient amount of vapour and gives a momentary flash when a test flame broughtnear it.Fire point: Fire point is the lowest temperature at which the oil gives sufficientamount of vapour and burns continuously when a test flame brought near it. This apparatus is used to determine the flash and fire point of an oil, if the fire point is less than 70°c

The flash point is a general indication of the flammability or combustibility of a liquid. Below the flash point, insufficient vapour is available to support combustion.

At some temperature above the flash point, the liquid will produce enough vapour to support combustion. (This temperature is known as the fire point. Flash points are measured by heating a liquid to specific temperatures under controlled conditions and then applying a flame. The test is done in either an “open cup” or a “closed cup” apparatus, or in both,7The fire point is defined as the lowest fuel temperature at which the diffusion flame is sustained longer than 5 s above the fuel pool without any external heat supply. The fire point for engine oils is usually 20-30 higher than flash point. A fire point happens when an ignition source is applied and the heat produced is self-sustaining, as it

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supplies enough vapors to combine with air and burn even after the removal of the ignition source.

There are two ways to measure the flash and fire point, open cup or closed cup experiments. Both methods involve heating the sample in a small cup and inserting an ignitor into the vapor.

1-Open cup:

The open-cup test was initially developed to assess the potential hazards of liquid spillage. An ignition source is passed horizontally over the surface of the liquid, while the cup and liquid are being heated, to test if the vapors ‘flash’. If the test is repeated at increasing test specimen temperatures a point may be reached at which the specimen continues to burn without further application of the ignition source, this is the fire point.

1- Closed cup: The closed-cup test contains any vapors produced and essentially simulates the situation in which a potential source of ignition is accidentally introduced into a container. In this test a test specimen is introduced into a cup and a close-fitting lid is fitted to the top of the cup. The cup and test specimen is heated. Subsequently, apertures are opened in the lid to allow air into the cup

and the ignition source to be dipped into the vapors to test for a flash.

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Fig. 1 (Cleveland open Cup Tester)

Fig.2 (Cleveland closed Cup Tester)

3. Apparatus and Materials:Cleveland open Cup Teste:

Cleveland open cup is used to determine the flash and fire point of all petroleum products. It consists of a cup contains oil is heated by an electrical heater. Power to the heater is regulated

Sample (kerosene and Gas oil)

4. Procedure:

1.Clean the cup (75 ml specimen) and fill the oil to be tested up to the mark.

2. Put it to the Cleveland tester tool.

3. Supply the electrical supply through a regular so that temperature of oil increases slowly. With a test flame, vapor above the cup is tested at an interval of 2°c rise of oil temperature. Note down whether flash occurs or not. Note down the flash pint.

4.After getting the flash point continue to heat the oil and vapor is tested at an interval of 2°c until fire point noticed Note down the fire point.

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Fig.3 (Cleveland open Cup Tester)

5. Calculations:

Test sample Flash point, ℃ Fire point, ℃Kerosene 62 64diesel 66 68

6. Discussion:

Flash point less then 23oC is dangerous and highly inflammable. The safe value is greater than 60oC. • Cleveland open cup tester used for volatile oils having flash point > 50oC. • Flash point give the idea about the volatility of fuel and the explosion hazard. • Fire point is the lowest temperature at which vapours given off by oil, ignite and continue to burn for at-least five seconds, when flame is applied. • Fire point is 5 – 40oC higher than flash point and is measured in same apparatus used for determination of flash point.

The typical flash point of the two samples that we used in the lab was

Diesel fuel flash points vary between 52 and 96 °C (126 and 205 °F).

The flash point of kerosene is between 37 and 65 °C (100 and 150 °F).

1) What are the factors affecting the flash point and fire point?

1. Frequency of application of test frame

2. Rate of heating 3. Rate of stirring

4. Size of test flame

5. Time of opening the shutter.)

More factors:

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pressure – The flash point temperature increases with increasing pressure and decreases with decreasing pressure.

Others - Tester configuration, sample size, ignition source, temperature control, sample homogeneity, drafts, and operator bias.

2) Different between flash and fire point

Every flammable liquid has a vapor pressure that increases with an increase in temperature.

The lowest temperature at which there is enough concentration of vapors in air to ignite the liquid is called its flash point. However, vapors cease to burn if the source of ignition is removed.

Fire point is slightly higher temperature at which these vapors continue to propagate and burn after removal of source of ignition

In general fire point is taken to be 10 degrees higher than flash point of flammable liquids.

3) What is the difference between open cup and closed cup tester?

The difference between the two methods is that that the cup is covered in the Closed Cup test which prevents any vapor from dissipating to the air.

Open Cup Flash Points Measuring a flash point using an open cup method is, as the name suggests, conducted in a vessel which is exposed to the air outside. The temperature of the substance is gradually raised and an ignition source is passed over the top of it, until it reaches a point at which it “flashes” and ignites. The flash point here will vary according to the distance between the substance and the ignition source – the height of the source above the cup.

The most commonly-used open cup method is known as the Cleveland open cup (COC).

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References:

http://www.slideshare.net/ThanmayJS/ec-lab-manual

http://www.petro-online.com/news/analytical-instrumentation/11/breaking_news/open_and_closed_cup_flash_point_what_is_the_difference/30654/

http://blog.anton-paar.com/a-guide-to-flash-and-fire-point-measurement/

http://www.differencebetween.com/difference-between-flash-point-and-vs-fire-point/

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