Atmospheric Distillation Column - Initial

After we have completed the steam specifications, the column model will run automatically and quickly converge to the solution. We may receive warnings about a potential aqueous phase in the Light Naphtha stream. We will ignore these warnings until we complete building the entire column model. 

---

Initially, petroleum Is distilled into fractions up to 350 C (650 F) under atmospheric pressure into gas, naphtha, middle distillates, gas oils, and residua. The atmospheric residua can be further distilled up to 350°C under vacuum to produce vacuum gas oils, lubricant oils, and vacuum residua. A modern refinery is no longer just a big distillation column that sells various boiling fractions to different consumer markets. While distillation is usually the first step, it is important to understand that a refinery processes 100,000 to 500,000 barrels of oil a day, and must turn every barrel of that oil into something that can be sold economically in the marketplace. For this reason, many of the crude oil fractions ( streams ) undergo catalytic transformation into more valuable streams and then are blended to produce petroleum products or petrochemicals that provide the highest value to the final end use. 

Dicyclopentadiene (50 g, 0.38 mole) is dissolved in 100 ml of anhydrous ether. Platinum oxide (0.25 g) is added, and the mixture is hydrogenated in a Parr apparatus at an initial pressure of 50 psi. Initially the reaction mixture becomes warm. The absorption of 2 mole equivalents of hydrogen takes 4-6 hours. The mixture is filtered by suction to remove the catalyst, and the filtrate is distilled at atmospheric pressure through a short fractionating column. 

Under an atmosphere of dry nitrogen gas, the dropping funnel is replaced by a fractional distillation apparatus provided with a 10-cm Vigreux column and a 5-cm water-cooled condenser. The system is heat-dried under a flow of nitrogen gas with an electric heat gun or may be assembled from oven-dried glassware. The mixture is then heated over a period of 20-30 min until the silicone oil bath reaches 130-140 °C. During this time, the initial yellow precipitate is partially dissolved and the mixture refluxes smoothly. The silicone oil bath is maintained at this temperature for an additional 30 min. Heating is then increased over the period of 1 h to achieve distillation of the product the final oil temperature reaches 200 to 215 °C. 

Several of the commercial simulation programs offer preconfigured complex column rigorous models for petroleum fractionation. These models include charge heaters, several side strippers, and one or two pump-around loops. These fractionation column models can be used to model refinery distillation operations such as crude oil distillation, vacuum distillation of atmospheric residue oil, fluidized catalytic cracking (FCC) process main columns, and hydrocracker or coker main columns. Aspen Plus also has a shortcut fractionation model, SCFrac, which can be used to configure fractionation columns in the same way that shortcut distillation models are used to initialize multicomponent rigorous distillation models. 

The reaction is completed by refltjxing for 2 days (twice for 10 hours) on the water bath. The product is then checked for malodorous methyltin halides which are initially present. If the odor is present, refltixing must be continued. The reaction mixture is then carefully decomposed with distilled water from the dropping funnel. The flask must be cooled with ice water, and addition is continued until the initial effervescence subsides. Finally, 10% hydrochloric acid is added until the precipitated Mg salt dissolves completely and two layers can be observed in the solution (if necessary, let stand for some time). The ether layer is separated in a separatory funnel and washed successively with some water and a 5% KF solution. Any methyltin halides still present are thus converted to the corresponding fluorides. These are insoluble and can be filtered off. The ether solution is dried for several hours with CaClg. Then most of the solvent is removed in a slow distillation with a suitable column. The remainder is fractionated at atmospheric pressure, using the same column. The boiling point of the pure substance is 76°C. The yield corresponds to about 90% of theoretical, based on the SnCl used. 

Purification procedures which depend primarily on the removal of interfering materials by partial polymerization of the monomer are usually not described in detail [22]. It appears that the monomer is generally warmed with a typical free-radical initiator until a slight increase in viscosity is observed. Then the impolymerized monomer is distilled off in an inert atmosphere through a fractionating column. The monomer may be predried with a zeolite such as Linde 4A prior to partial polymerization and fractional distillation [29]. 

Operation is at 1.0 atmosphere. The batch distillation system consists of a still pot plus a column with the equivalent of 9 equilibrium contacts and a total condenser. We operate at a constant external reflux ratio of 2/3. The initial charge to the still pot is 1000.0 kg. We desire a final still pot concentration of 0.004 mole fraction ethanol. Equilibrium data are in Table 2-1. Convert the amount of feed to kmole using an average molecular weight. Find Wfjnai and D otai in kmole, and... 

---