Heavy distillate

During the production of mineral oils from vacuum distillates, one of the process steps, dewaxing , removes the high melting point materials in order to improve the oil s pour point. Dewaixing produces paraffins and waxes, the first coming from light distillates, and the second from medium or heavy distillates. 

Solvent deasphalting. This is an extraction of the heaviest fractions of a vacuum residue or heavy distillate. The extract is used to produce the bitumen. The separation is based on the precipitation of asphaltenes and the dissolution of the oil in an alkane solvent. The solvents employed are butane or propane or a butane-propane mixture. By selecting the proper feedstock and by controlling the deasphalting parameters, notably temperature and pressure, it is possible to obtain different grades of bitumen by this process. 

Vacuum distillation of the atmospheric residue complements primary distillation, enabli r.ecoyery of heavy distillate cuts from atmospheric residue that will un r o further conversion or will serve as lube oil bases. The vacuum residue containing most of the crude contaminants (metals, salts, sediments, sulfur, nitrogen, asphaltenes, Conradson carbon, etc.) is used in asphalt manufacture, for heavy fuel-oil, or for feed for others conversion processes. 

Property 0-GT" Naphtha 1-GT" Light distillate 2-GT" Medium distillate 3-GT Heavy distillate 4-GT Heavy residual... 

The principal sources of feedstocks in the United States are the decant oils from petroleum refining operations. These are clarified heavy distillates from the catalytic cracking of gas oils. About 95% of U.S. feedstock use is decant oil. Another source of feedstock is ethylene process tars obtained as the heavy byproducts from the production of ethylene by steam cracking of alkanes, naphthas, and gas oils. There is a wide use of these feedstocks in European production. European and Asian operations also use significant quantities of coal tars, creosote oils, and anthracene oils, the distillates from the high temperature coking of coal. European feedstock sources are 50% decant oils and 50% ethylene tars and creosote oils. 

Product Recovery. The aHyl chloride product is recovered through the use of several fractional distillation steps. Typically, the reactor effluent is cooled and conducted into an initial fractionator to separate the HCl and propylene from the chloropropenes, dichloropropanes, dichloropropenes, and heavier compounds. The unconverted propylene is recycled after removal of HCl, which can be accompHshed by adsorption in water or fractional distillation (33,37,38) depending on its intended use. The crude aHyl chloride mixture from the initial fractionator is then subjected to a lights and heavies distillation the lighter (than aHyl chloride) compounds such as 2-chloropropene, 1-chloropropene, and 2-chloropropane being the overhead product of the first column. AHyl chloride is then separated in the second purification column as an overhead product. Product purities can exceed 99.0% and commercial-grade aHyl chloride is typicaHy sold in the United States in purities about 99.5%. 

TBP cut point between the heavy distillate and the bottoms = 650°F. Percent overflash = 2 volume percent of feed. 

General Fuel Type True Distillate Naphthas Blended Heavy Distillates Low-Ash Crudes Residuals High-Ash Crude... 

Finally, the weight of a fuel, light or heavy, refers to volatility. The most volatile fuels vaporize easily and eome out early in the distillation proeess. Heavy distillates will eome out later in the proeess. What remains after distillation is referred to as residual. The ash eontent of residual fuels is high. 

Hydrofining usually involves only minor molecular changes of the feed with hydrogen consumption in the range of about 100 to 1,000 cu.ft./bbl. Typical applications include desulfurization of a wide range of feeds (naphtha, light and heavy distillates, and certain residua) and occasional pretreatment of cat cracker feeds. 

J. V. Bmnnock, Separation and distribution of normal paraffins from petroleum heavy distillates by molecular sieve adsorption and gas cliromatogr aphy , Anal. Chem. 38 1648-1652(1966). 

Another U.S. policy to attain energy independence was to force all Alaskan North Slope crude oil to he consumed inside the United States and not be allowed to he exported. The problem was that North Slope crude oil is relatively heavy and not suitable for west coast fuel needs. The mismatch of supply and demand caused California refineries to sell heavy distillate fuels abroad and import lighter fuel additives. Furthermore, the forced selling of Alaska crude oil on a very saturated west coast market caused Alaska crude prices to he 1 to 5 per barrel less than the international price, resulting in less oil exploration and development in Alaska. The upshot of all this was lower tax revenue, a loss of jobs in the oil fields, and less oil exploration and development on the North Slope. The United States actually exported heavy bunker fuel oil at a loss, as opposed to the profit that could have been attained by simply exporting crude oil directly. 

Fuel oil that is used for heating is graded from No. 1 fuel oil to No. 6 fuel oil, which covers light distillate oils, medium distillate, heavy distillate, a blend of distillate and residue, and residue oil. For example. No. 2 and No. 3 fuel oils medium to light distillate grades used in domestic central heating (Table 3.7). 

Some PAHs (e.g., phenanthrene, pyrene, and benzo[g,/z,i]perylene) are commonly seen in products boiling in the middle to heavy distillate range. In a method for their detection and analysis (EPA 8310), an octadecyl column and an aqueous acetonitrile mobile phase are used. Analytes are excited at 280 nm and detected at emission wavelengths of >389 nm. Naphthalene, acenaphthene, and fluorene must be detected by a less sensitive UV detector because they emit light at wavelengths below 389 nm. Acenaphthylene is also detected by UV detector. 

Gasoline 333 gallons per tonne Light distillate 285 gallons per tonne Heavy distillate 256 gallons per tonne Crude oil 272 gallons per tonne... 

Since CPP cracking effluent is molecularly similar to that of heavy distillate cracking it will be logical to construct integrated CPP-steam cracker units, or even to add a CPP reactor-regenerator as a revamp side-cracker expansion feature. Various plans are under review for such prospective projects. 

In naphtha and light distillate components, oxygen-containing compounds appear as carboxylic acids and phenols. Most of these compounds concentrate in the kerosene, fuel oil, and lighter lubricant fractions. Straight-run gasoline, heavy distillates, and residual fuels usually contain few acids. 

Light Low-pour-point heavy distillate fuel for use in pressure-atomizing type burners... 

It is recommended that any higher-viscosity product such as residual oil or heavy distillate fuel be evaluated for changes in low-temperature handling properties over time. Testing for reversion in pour point by the Shell Amsterdam Reversion Test or the British Admiralty Pour Point Reversion Test are recommended. Also, viscosity increase versus temperature decrease determinations are recommended for products stored at low temperatures for extended periods of time. 

Macrocrystalline wax is larger in size and typically contains waxes from 17 to approximately 30 carbons in length. Plate structure wax is macrocrystalline in form and can be found in low concentration in some distillate fuel. Heavy distillates and residual oils can contain higher concentrations of macrocrystalline wax. 

The liquids used during WWI and WWII were combinations of heavy and light distillates of petroleum, coal rar or wood tar. The presence of small amounts of light distillates Is necessary in order to secure easier ignition, while the presence of heavy distillates is necessary because heavy liquids can be thrown farther and are longer-burning... 

Generally, the heavy materials removed in the process included both resins and asphalts, but by operating in two or more stages, these materials can be segregated. This may often be desirable, as both products then may be obtained in a relatively pure state and thus they become of greater commercial importance. Deresining of heavy distillate fractions also is possible, and the process may be operated for the separation of special resin fractions (38), which may be of value in the manufacture of specialty products. 

A single-step reaction at 430°C for 3 hr eliminated only 30% of the nitrogen from the heavy distillate of a Wandoan coal liquid (bp 350-500°C) as shown in Table 11. In marked contrast, a 100% denitrogenation was... 

Two-Stage Hydrodenitrogenation of Coal Heavy Liquid Heavy Distillate... 

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