Kerosene cracking

Fractions treated by this process are light products from the primary distillation LPG to Kerosene, or light products from thermal and catalytic cracking (visbreaking, coking, FCC). 

Gas oil is a product hoiling slightly higher (235—425°C, or sometimes wider) than kerosene. The main feedstock to the catalytic cracking units (see Feedstocks), it received its name from use as an enriching agent in the production of city or manufactured gas. It is often used as diesel fuel. 

A modem petroleum refinery is a complex system of chemical and physical operations. The cmde oil is first separated by distillahon into fractions such as gasoline, kerosene, and fuel oil. Some of the distillate fractions are converted to more valuable products by cracking, polymerization, or reforming. The products are treated to remove undesirable components, such as sulfur, and then blended to meet the final product specifications. A detailed analysis of the entire petroleum production process, including emissions and controls, is obviously well beyond the scope of this text. 

In single-stage units which do not produce kerosene or other critical stocks, flash zone temperatures may be as high as 750 - 775 F. The principal limitation is the point at which cracking of distillates to less valuable gas or the rate of coke formation in the furnace tubes becomes excessive. 

Gas oil, which is heavier than kerosene, is the raw material of choice in cracking and other refinery operations. Cracking of gas oil produces a variety of fuels for automotive, industrial, and domestic (furnace) use. 

Consecutively, the heavy paraffins are cracked into lighter hydrocarbon fractions by hydro-cracking. For example, for the Shell Middle Distillate Synthesis (SMDS) process, the liquid product stream is composed of 60% gasoil (diesel), 25% kerosene and 15% naphtha. The gaseous product mainly consists of LPG (a mixture of propane and butane) (Eilers et al., 1990). Figure 7.3 shows a simplified diagram comprising all process steps to produce synthetic hydrocarbons from biomass, natural gas and coal. 

Palm oil has been cracked at atmospheric pressure and a reaction temperature of 723 K to produce biofuel in a fixed-bed microreactor. The reaction was carried out over microporous HZSM-5 zeolite, mesoporous MCM-41, and composite micromesoporous zeolite as catalysts. The products obtained were gas, organic liquid product, water, and coke. The organic liquid product was composed of hydrocarbons corresponding to gasoline, kerosene, and diesel boiling point range. The maximiun conversion of palm oil, 99 wt.%, and gasoUne yield of 48 wt.% was... 

The distillate manufacturing processes of diesel fuel oils, such as fuel oil 1-D and fuel oil 2-D, are similar to those of fuel oil no. 1 and fuel oil no. 2, respectively (lARC 1989). Fuel oil no. 1-D is manufactured from a straight-run distillate process. Diesel fuel oil (1-D, 2-D) is defined as the fraction of petroleum that distills after kerosene (Air Force 1989). Fuel oil no. 2-D is also made from mixing of straight-run and catalytically cracked distillates (LARC 1989). 

Today s diesel fuel grades are blends which may contain straight-run distillate, cycle oil, various gas oils, and heavy cracked distillates. Kerosene or jet fuel may be blended into the diesel to improve the low-temperature viscosity and handling characteristics of the fuel. 

Recently, Takenaka et studied a series of base metal catalysts supported on various ceramic oxides for catalytic cracking of kerosene fuel. Yields of H2 and methane from a model kerosene fuel (52 wt% n-Ci2, 27 wt% diethylbenzene and 21 wt% t-butylcyclohexane) over various base metals at 600°C are shown in Figure 33. Ni/Ti02 showed the highest catalytic activity for the cracking reaction of kerosene fuel, and also maintained a better performance for the kerosene feed that contained benzothiophene. However, the catalytic performance of the... 

The extraction process can be performed in acidic conditions which produces the cocaine as its hydrochloride salt. Alkaline conditions will produce a lipophilic "free base" which can be extracted with a nonpolar solvent like ether. The ether can be volatilized with heat and the free base smoked, snorted, injected, or eaten. The salt form cannot be smoked. Cocaine paste, not common in the U.S. is a kerosene extract which may contain 20-90% cocaine sulfate. Crack is the result of free-basing with baking soda (sodium bicarbonate). The residual fillers and other impurities... 

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