Flash And Fire Point 1b5u7

King Saud University College of Engineering Department of Chemical Engineering First semester of 1431/1432H

CHE 441 Flash and Fire Point

Name:

Dafer M. Al-Shahrani

Univ. No.: 462103969

Supervised by: Dr. Tariq El-Faris Eng. Mohammad Gelly 1

♠ Contents : Pag e

Subject

Summary

3

Introduction and Theory

3,4

Experimental Procedure

4

Schematic Diagram

5

Results & Computations

5

Discussions & Conclusions

6

References

6

Appendix

6

2

♠ Summary : The objective of experiment is to determine the flash and fire point for different types of oils. Result in table 1.

♠ Introduction & Theory : The flash point of a volatile liquid is the lowest temperature at which it can vaporize to form an ignitable mixture in air. Measuring a liquid's flash point requires an ignition source. At the flash point, the vapor may cease to burn when the source of ignition is removed. The flash point is not to be confused with the auto ignition temperature, which does not require an ignition source. The fire point, a higher temperature, is defined as the temperature at which the vapor continues to burn after being ignited. Neither the flash point nor the fire point is related to the temperature of the ignition source or of the burning liquid, which are much higher. The flash point is often used as a descriptive characteristic of liquid fuel, and it is also used to help characterize the fire hazards of liquids. “Flash point” refers to both flammable liquids and combustible liquids. There are various standards for defining each term. Most people agree that liquids with a flash point less than 60.5°C (141°F) or 37.8°C (100°F) are flammable, and liquids with a flash point above those temperatures are combustible.[1]

Mechanism Every liquid has a vapor pressure, which is a function of that liquid's temperature. As the temperature increases, the vapor pressure increases. As the vapor pressure increases, the concentration of evaporated flammable liquid in the air increases. Hence, temperature determines the concentration of evaporated flammable liquid in the air. Each flammable liquid requires a different concentration of its vapor in air to sustain combustion. The flash point of a flammable liquid is the lowest temperature at which there will be enough flammable vapor to ignite when an ignition source is applied.[1]

Measuring flash points There are two basic types of flash point measurement: open cup and closed cup.

3

In open cup devices the sample is contained in an open cup which is heated, and at intervals a flame is brought over the surface. The measured flash point will actually vary with the height of the flame above the liquid surface, and at sufficient height the measured flash point temperature will coincide with the fire point. The best known example is the Cleveland open cup (COC). There are two types of closed cup testers: non-equilibrium, such as Pensky-Martens where the vapours above the liquid are not in temperature equilibrium with the liquid, and equilibrium, such as Small Scale (commonly known as Setaflash) where the vapors are deemed to be in temperature equilibrium with the liquid. In both these types the cups are sealed with a lid through which the ignition source can be introduced. Closed cup testers normally give lower values for the flash point than open cup (typically 5-10 °C) and are a better approximation to the temperature at which the vapor pressure reaches the lower flammable limit (LFL) .[1]

♠ Experimental Procedure :     

Filled the cup with the oil. S C increased this was when there was a lot of vapors formed over the cup. Recorded the lowest temperature at which application of a flame caused the vapors above the surface of liquid to ignite as the flash point. Continued the heating and recorded the lowest temperature at which application of flame caused the liquid (petroleum product and other fluids) to burn for at least 5 sec fire point. Cleaned the cup and repeated steps 1-5 for other samples.

4

♠ Schematic Diagram :

Fig1: Flash and Fire Point with Open Cup.[3]

♠ Results & Computations : Table 1: Readings and result of experiment.

Test Type Flash Point (C) Fire Point (C)

Gulf 100 258 270

5

Gulf 700 184 210

♠Discussion and Conclusions :  The temperature Flash point for gulf 100 greater than for gulf 700.  The temperature Fire point for gulf 100 greater than for gulf 700.  The reason is because the density of gulf 100 higher than the density of gulf 700.

♠References : [1] http://en.wikipedia.org/wiki/Flash_point [2] Note of Petroleum Engineering Laboratory. [3] www.petrotest.com/index_256e77448c5d143f37250...

♠Appendix :

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