Straight run gas oil

Euel oil, residues-straight-run gas oils, high sulphur Euel oil, residual... 

Trickle-bed operation is the oldest and the most commonly used its development is described in a recent publication (VI). Cobalt-molybdenum catalysts may be used at a temperature of 360°C and a pressure of 57 atm for the hydrogenation of straight-run gas oils. 

The DS7 strain is characterized for its activity on the representative sulfur groups of the molecules present in fuel producing cuts, both gasoline and diesel. Examples given include straight-run gas oils, gas oils from hydrodesulfurization and the main streams coming from the atmospheric distillation of petroleum (cuts 70-160°C, 160-230°C and 230-350°C.),... 

Fluid catalytic cracking (FCC) (Fig. 13.5) was first introduced in 1942 and uses a fluidized bed of catalyst with continuous feedstock flow. The catalyst is usually a synthetic alumina or zeolite used as a catalyst. Compared to thermal cracking, the catalytic cracking process (1) uses a lower temperature, (2) uses a lower pressure, (3) is more flexible, (4) and the reaction mechanism is controlled by the catalysts. Feedstocks for catalytic cracking include straight-run gas oil, vacuum gas oil, atmospheric residuum, deasphalted oil, and vacuum residuum. Coke inevitably builds up on the catalyst over time and the issue can be circumvented by continuous replacement of the catalyst or the feedstock pretreated before it is used by deasphalting (removes coke precursors), demetallation (removes nickel and vanadium and prevents catalyst deactivation), or by feedstock hydrotreating (that also prevents excessive coke formation). 

Two feeds have been used, a Middle East medium straight run gas-oil (SRGO) and a mixture (50/50vol) of the same SRGO and an FCC light cycle oil (LCO). The analysis of the SRGO, LCO and the mixture are reported in Table 1. 

The observation that vacuum residue causes significant coke deposition on catalysts was further ascertained by conducting a special test run (Run R05) which is similar to Run R02 except straight run gas oil was used instead of vacuum residue as feedstock at 380 °C. The... 

Because the boiling ranges, sulfur contents, and other properties of even the same fraction vary from crude oil to crude oil and with the way the crude oil is processed, it is difficult to specify which fractions are blended to produce specific fuel oils. In general, however, furnace fuel oil is a blend of straight-run gas oil and cracked gas oil to produce a product boiling in the 175-345°C (350-650°F) range. 

As in the traditional acid extraction process, the feedstock is generally dewaxed solvent refined base stock, since levels of the aromatics, polynuclear aromatics, and nitrogen and sulfur compounds are already reduced relative to a straight-run gas oil. This facilitates hydroprocessing by lightening the load on the catalysts and extending their lives. Equally important is that this is an already dewaxed feed, so the white oil producer does not have to bear the capital costs of crude fractionation and dewax units. 

Between 1990 and 1999, the global capacity of hydrotreatment had already increased by more than 40 % and is expected to continue to grow in the coming years. Certain cuts that escaped hydrodesulphurization in the past will have to undergo this treatment in the future (certain kerosenes and straight run gas oils or FCC gasolines). 

Figure 14.13 TEM micrographs of sulfided N1-M0/AI2O3 catalysts [92] (a) after liquid-phase sulfidation (DMDS spiked straight run gas oil (SRGO), 30 bar, 320°C) and (b) after H2S/H2 sulfidation (10% H2S in H2, 1 bar, 300°C).

Feedstock Calif. straight-run gas oil Calif. coker-gas oil Gachsaran gas oil ... 

In this work a study about the effect of external difiiision on the hydrodesulfurization reaction of straight run gas oil is presented. The experimental study was carried out at typical HDS operating conditions over a commercial catalyst using an iqiflow and downflow trickle-bed microreactor (TBMR). The experimental results showed that upflow is the best system for conducting kinetic studies in order to avoid interphase mass transfer limitations. 

Experimental results about the hydrodesulfurization of straight run gas oil over a commercial Ni-Mo/Al203 catalyst are presented. The tests were conducted in an upflow and downflow microreactor at pressure of 54 kg/cm, hydrogen-to-oil ratio of 2000 ft /bbl. LHSV and reaction temperature were studied on the renges of 1-2.5 and 340-380°C, respectively. 

The set of kinetic experiments was conducted in a bench-scale HDT unit. The plant consisted of two FBRs in series (-500 cm of catalyst in each reactor) which were loaded with a triple layer of catalyst extrudates a front-end HDM catalyst, a mid-end catalyst with balanced HDM/HDS activity, and a tail-end highly active catalyst for HDS and HCR. Catalysts were activated in situ by sulfiding with spiked straight-run gas oil (1.46 wt% sulfur, also containing 1.0 wt% dimethyl disulfide). The feedstock was an AR (343°C-i-) from a Mexican heavy crude oil (13°API). 

Cetane index, as defined by ASTM D976, is not a measurement, but the result of a calculation based on density and mid-boiling point. It is nearly the same the as cetane number for diesel fuels comprised mostly of straight-run gas oils blended with lesser amounts of cracked stocks. Diesel index is a ... 

Fig. 2 illustrates the diversity of composition by showing the elemental distribution of some typical petroleum fractions, such as LCO (light cycle oil), MCO (medium cycle oil), SRGO (straight run gas oil), H-SRGO (hydrotreated straight run gas oil), and gasoline, as determined by GC-AED... 

Figure 2. AED Chromatograms of Various Fuel Oils. LCO light cycle oil, MCO medium cycle oil, VGO(hexane soluble fraction) Vacuum Gas Oil, SRGO straight run gas oil, H-SRGO hydrotreated straight run gas oil. (Cn Paraffin with n carbons, T Thiophene, BT Benzothiophenes, DBTiDibenzothiophene, Cz Carbazole, DM Dimethyl, EM Ethylmethyl, TM Trimethyl.)...

Fig. 2 illustrates the sulfur distribution of a current 300 ppm diesel fuel (HSRGO). Comparison of its sulfur distribution to that of the straight run gas oil (SRGO) revealed that 100% of reactive sulfur species and 80% of refractory sulfur species are removed to obtain 300 ppm by current HDS units. The nitrogen species in the 300 ppm diesel are also illustrated in the same figure, showing carbazole of 50 ppm. 

Kuwait Straight Run Gas Oil (SRGO) Blend of 25% light coker oil (LCO) and 75% SRGO... 

Figure 4 shows product sulfur as a function of temperature for the three catalysts on the blend of 75% straight run gas oil and 25% light coker oil (LCO). In these tests, the hydrogen to oil ratio was 500 Nl/1, and the hydrogen pressure was 30 bar. LHSV was held constant. 

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