Diesel fuel flash point

Diesel Fuel Safety as Characterized by Its Flash Point... 

The flash point of a petroleum liquid is the temperature to which it must be brought so that the vapor evolved burns spontaneously in the presence of a flame. For diesel fuel, the test is conducted according to a closed cup technique (NF T 60-103). The French specifications stipulate that the flash point should be between 55°C and 120°C. That constitutes a safety criterion during storage and distribution operations. Moreover, from an official viewpoint, petroleum products are classified in several groups according to their flash points which should never be exceeded. 

It should be noted finally that adding gasoline to diesel fuel which was sometimes recommended in the past to improve cold behavior conflicts with the flash point specifications and presents a serious safety problem owing to the presence of a flammable mixture in the fuel tank airspace. Adding a kerosene that begins to boil at 150°C does not have the Scune disadvantage from this point of view. 

Liquid fuels for ground-based gas turbines are best defined today by ASTM Specification D2880. Table 4 Hsts the detailed requirements for five grades which cover the volatility range from naphtha to residual fuel. The grades differ primarily in basic properties related to volatility eg, distillation, flash point, and density of No. 1 GT and No. 2 GT fuels correspond to similar properties of kerosene and diesel fuel respectively. These properties are not limited for No. 0 GT fuel, which allows naphthas and wide-cut distillates. For heavier fuels. No. 3 GT and No. 4 GT, the properties that must be limited are viscosity and trace metals. 

Biodiesel does not present any special safety concerns. Pure biodiesel or biodiesel and petroleum diesel blends have a higher flash point than conventional diesel, making them safer to store and handle. Problems can occur with biodiesels in cold weather due to their high viscosity. Biodiesel has a higher degree of unsaturation in the fuel, which can make it vulnerable to oxidation during storage. 

The oil for an oil-base mud can be diesel oil, kerosene, fuel oil, selected crude oil, or mineral oil. There are several requirements for the oil (1) API gravity = 36° - 37°. (2) flash point = 180°F or above, (3) fire point = 200°F or above, and (4) aniline point = 140°F or above. Emulsifiers are more important in oil-base mud than in water-base mud because contamination on the drilling rig is very likely, and it is very detrimental to oil mud. Thinners, on the other hand, are far more important in water-base mud than in oil-base mud oil is dielectric, so there are no interparticle electric forces to be nullified. 

The oil used should be of a volatile type, as the more volatile oils gives the greatest sensitivity. However, the use of petroleum fractions with too low a flash point is hazardous. The choice is, therefore, usually made of a fuel oil similar to those used for diesel engines. It is common practice to add a proportion of dyestuff to the oil, partly to make adequate mixing of the explosive immediately visible, and partly to assist the user in seeing proper loading of boreholes, particularly in salt and other white materials. 

An extensive review has been conducted to identify potential oxygenates for blending into diesel fuels [55]. Over 70 molecules were identified and tested, taking into account numerous physical properties such as oxygen content, flash point, viscosity, cetane number, corrosivity, toxicity, and miscibility with diesel blends. Five key aspects were considered critical to develop commercially valuable diesel additives ... 

Experiments [43] with very high flash point fuels (JP, kerosene, Diesel, etc.) revealed that the flame propagation occurred in an unusual manner and a much slower rate. In this situation, at ambient conditions, any possible amount of fuel vapor above the liquid surface creates a gaseous mixture well outside the fuel s flammability limits. What was discovered [44, 45] was that for these fuels the flame will propagate due to the fact that the liquid surface under the ignition source is raised to a local temperature that is higher than the cool ambient temperature ahead of the initiated flame. Experimental observations revealed [45] that this surface temperature variation from behind the flame front to the cool region ahead caused a variation in the surface tension... 

Liquids with flash points from (1.068 X 10 sq m/s)] at 122°F (SOX) dry fuel oils, etc. Kerosene, light furnace oils, diesel 30... 

The presence of low molecular weight, low flash point compounds in diesel fuel could lead to a shortening of the fuel ignition delay period. In a diesel engine, this could cause rough running due to early combustion of the low flash point compounds. 

Fuel Oils Refined petroleum products having specific gravities in the range of 0.85 to 0.98 and flash point temperatures above 55 °C. This includes auto diesel, industrial heating fuels, various bunker fuels, furnace fuels. Refer to Chapter 4 for specific examples and discussion of properties. Fuel Value Refers to the amount of potential energy that can be released by a fuel during combustion. Expressed in units of BTUs per pond of fuel. Examples are asphalt (17,158 BTU/lb typical value), LPG (18,000 BTU/lb), wood shavings (8,250 BTU/lb). 

Fuel Oils Refined petroleum products having specific gravities in the range from 0.85-0.98 and flash points greater than 55°C includes furnace, auto diesel, and stove fuels, plant or industrial heating fuels and various bunker fuels. 

Also according to Van Dolah ammonium nitrate-oil mixtures offer a certain dust explosion hazard and any electric equipment (switches controls, motors, lights) located in the plant should conform to the safety requirements or should be installed outside the plant. In order not to increase the dust explosion hazard no liquid hydrocarbon fuel with higher volatility than No. 2 Diesel fuel (minimum flash point of 145°F, ASTM closed-cup procedure) should be used as an admixture to ammonium nitrate. More volatile fuels, such as gasoline, kerosine or No. 1 Diesel fuel cannot be recommended according to Van Dolah, as they would seriously increase the hazard of a vapour explosion. 

Biodiesel is believed to be a promising alternative fuel to substitute petroleum-derived diesel fuel in diesel engines, and essentially no engine modifications are required to substitute biodiesel for diesel fuel. In addition, biodiesel is better than diesel fuel in terms of sulfur content, flash point, aromatic content, and biodegradability (1). Research on the commercial application of biodiesel has therefore been started in European countries, the United States, and Japan (2,3). 

In a diesel engine the contamination comes from the above and additional sources such as (a) soot as a normal by-product of diesel engine will increase the viscosity of the oil and become abrasive as its level increases in the oil (b) the fuel dilution will reduce the film strength of the oil to a point where accelerated wear occurs (c) the fuel dilution will reduce the flash-point of the oil (d) a diesel engine oil will also be exposed to the formation of acid from the sulfurized fuel max.5% a diesel engine will have a high TBN to assist it in combating the acid formation. 

The optimum pyrolysis temperature is 395°C to give a recovery ratio of 0.97 (i.e. 1000 kg polystyrene will yield 970 L liquid monomer) and 5 to 10% char residue. Fuel made from polystyrene feedstock will be high in aromatic character and have an energy content of 50 MJ/kg and a pour point of —67°C. However the flash point is only 26°C and the cetane rating only 12.6. The fuel needs to be blended with polyolefin-derived diesel or regular diesel in order to upgrade the flash point and cetane rating to within specification. 

The RON of gasoline obtained by thermal cracking or catalytic cracking is generally just about 80, and the flash point of diesel oil product is also very low. By isomerization and aromatization, catalytic reforming of cracked gas can greatly improve the quality of liquid fuel products. 

It is shown that after catalytic reformation, the quahty of liquid fuel produced is improved greatly. RON of gasoline reached more than 90 and the flash point of diesel oil also increased. 

---