Topped crude

A combination unit is a special type of unit that was developed to reduce the investment for a small refinery. In effect, one main distillation unit serves as a crude fi-actionator as well as the cat unit primary fractionator. This same tower also serves the naphtha reformer and visbreaker. A schematic diagram of a combination unit is shown in Figure 2. Crude oil is topped (material boiling below 650°F is removed) in the atmospheric tower, and the topped crude is sent to the combination tower along with cat products and naphtha reformer products. These latter streams provide heat to distill the topped crude and also, being more volatile than topped crude, provide a lifting effect which assists in vaporizing more of the crude. 

Gas oil is a heavier petroleum fraction than kerosine. It can be obtained from the atmospheric distillation of crude oils (atmospheric gas oil, AGO), from vacuum distillation of topped crudes (vacuum gas oil, VGO), or from cracking and hydrocracking units. 

Figure 2.2. DSC thermograms of n = 6 monomer illustrating melting point processing window at three stages of purification (top, crude monomer product middle, insufficiently purified monomer bottom, sufficiently purified monomer).

Petroleum Sulfonation Process Developments. Crude oil and/or topped crude oil were sulfonated using S03 by Marathon Oil... 

In one continuous method (17), the waxy oil charge—for example, in the case of a topped crude—is diluted with an equal volume of propane and the mixture is chilled to about —25° F. by means of heat exchange with cold filtrate in double-pipe scraped-surface equipment. This chilled mixture is then mixed with propane which has been chilled by autorefrigeration to —45° F. to bring the ratio of propane to oil to about 5 to 1. Ninety per cent of the refrigeration required is accomplished in this manner the remaining 10% is obtained by evaporating propane from the diluted mixture. 

Residual Fuel Oils—Topped crude petroleum or viscous residuums obtained in refinery operations. Commercial grades of burner-fuel oils Nos. 5, and 6 are residual oils and include Bunker fuels. 

Topped Crude—A residual product remaining after the removal, by distillation or other processing means, of an appreciable quantity of the more volatile components of crude petroleum. 

Kuwait residual, Agha Jari topped crude... 

Agha Jari topped crude Gach Saran atmospheric residuum Kuwait and Lagomedio atmospheric residual 3 Jobo crude resin fraction asphaltene fraction Adriatic Sea atmospheric resid Gach Saran vacuum residuum... 

Topped crude oil must always be stripped with steam to elevate the flash point or to recover the final portions of gas oil. The composition of the topped crude oil is a function of the temperature of the vaporizer (or flasher). 

The HOT process is a catalytic cracking process for upgrading heavy feedstocks such as topped crude oils, vacuum residua and solvent deasphalted bottoms using a fluidized bed of iron ore particles (Ozaki, 1982). 

These processes are designed to remove sulfur, nitrogen, asphaltene, and metal contaminants from residua and are also capable of accepting whole crude oils or topped crude oils as feedstocks (Brossard, 1997 Hydrocarbon Processing, 1998). The major product of the processes is a low-sulfur fuel oil and the amount of gasoline and middle distillates is maintained at a minimum to conserve hydrogen. 

Topped crude petroleum that has had volatile constituents removed up to a certain temperature, e.g., 250°C (480°F+) topped crude not always the same as a residuum ([Pg.457]

With Arabian topped crude, the solvent loses its enhancement... 

Supercritical Hydrotreatment of Arabian Topped Crude. A series of experiments were performed with Arabian topped crude (650F+) to investigate the hydrotreatment of high sulfur crudes in the presence of a light solvent under supercritical conditions. The experimental results obtained are summarized in Table IV. The overall results are comparable to those obtained from the supercritical hydrotreatment of SCE shale oil (Run l). The sulfur removal is very extensive (about 99 removal, reduced from 3.355 to 0.02 ). The nitrogen content in the heavy oil fractions are relatively low, less than 60 ppm for runs with total liquid hourly space velocity (LHSV) of 0.5 (Runs 6 and 7) and about 770 ppm for Run 8 with an LHSV of 1.6. Thus, for extensive nitrogen removal, lower LHSV is needed. 

The effect of crude oil concentration in the feed was investigated with Arabian 65OF+ topped crude. Three concentrations (20, 50 and 80 of topped crude in toluene) were chosen, while... 

Figure 2. Effect of oil concentration in supercritical hydrotreatment of arabian topped crude.

Table IV. Supercritical Hydrotreatment of Arabian Topped Crude (ATC) (850F, 11 00 psig, H2 GHSV-300, Nalco Ni-Mo Catalyst)...

Runs 9 and 10 were carried out to study the effect of an aliphatic solvent such as n-heptane in supercritical hydrotreating of topped crude. Comparing the results from Runs 6 and 7 in which toluene was used as the solvent, the nitrogen contents in heavy oil fractions are much lower for the heptane runs than the toluene runs. The sulfur contents are about the same. Thus, one can conclude that an aliphatic solvent is better solvent for hydrodenitrogenation than the aromatic solvent. The reason is that the aromatic solvent was competing for hydrogenation (about 1 wt of the toluene was converted to methyl cyclohexane). 

The use of a non-aromatic solvent as the supercritical hydrotreating solvent was studied first with Arabian topped crude and then with Paraho shale oil in hope of reducing hydrogen consumption. The results are tabulated in Tables IV and VI. 

Split 2 top crude VCM/bottoms crude EDC Split 3 top Lights (CLP)/bottoms crude EDC Split 4 top pure EDC/bottoms TCE and heavies... 

Cracking of a topped crude oil (sp. gr. 0.91-0.93, 45% boiling below 300°C.) over silica-alumina at 310-355°C. was reported by the Institute of Mineral Fuels (186). A 20% yield of gasoline boiling below 200°C. was obtained. The catalyst was prepared from a natural mineral and resembled aluminum chloride in its action. 

Generally gas oil for catalytic cracking has a boiling point of about 630-1025°F. Gas oil is produced by vacuum distillation of atmospherically topped crude. Figure 1 gives a schematic diagram of... 

The topped crude is typically reduced by two-thirds of the total naphtha cut. The bottoms from the second pre-flash tower are sent to the charge heater and directed to the main distillation column and produce four product streams heavy naphtha, several kerosene cuts, and bottoms residue. The residue is further processed in a vacuum column and produces VGO and several distillate streams. 

Crude Oil A mixture of hydrocarbons that exists in liquid form at atmospheric pressure after passing through surface separating facilities. Included are lease condensate and liquid hydrocarbons produced from tar sands, Gilsonite and oil shale. Drip gases are also included, but topped crude oil (residual) and other unfinished oils are excluded. Liquids produced at natural gas processing plants and mixed with crude oil are likewise excluded where identifiable. 

Gas oil above 500°F, vegetable oil Liquid naphtha above 500°F, quenching oils Topped crude (below 25°API), fuel oil Cracked residuum, coke-oven gas, illuminating gas... 

The desulfurization of heavy fuel oil is generally categorized as direct or indirect. Feedstocks for the direct process can be a whole crude, top crude, an atmospheric residuum, or a vacuum residuum. The indirect process for desulfurization is similar to the direct process except that it is applied to a vacuum gas oil fraction, after which the desulfurized product is blended with either an undesulfurized vacuum residuum, a desulfurized vacuum residuum, a naturally occurring low-... 

Desalted hot crude oil feed is sent to a preflash column where it is separated into gas, gasoline, naphtha, and topped crude as shown in Figure 9.5. Using column modules representation, determine the number of degrees of freedom for this operation. What specifications may be used to define the column performance The crude feed is of fixed composition and thermal conditions. The stripping steam thermal conditions are fixed, but its flow rate may be varied. The column pressure is independently fixed. 

Purification takes place by distillation in a series of three columns, separating the following products in succession at the top crude add (=70 trays), sent to the recovery stage, giarial acetic add (=100 trays), recyded to pyrolysis and absorption, and acetic anhydride in a purity of over 99 per cent (=10 trays). The heavier components are collected at the bottom of the final fractionation. 

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