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Vacuum units

Vacuum Treatment. Milk can be exposed to a vacuum to remove low boiling substances, eg, onions, garlic, and some silage, which may impart off-flavors to the milk, particularly the fat portion. A three-stage vacuum unit, known as a vacreator, produces pressures of 17, 51—68, and 88—95 kPa (127, 381—508, and 660—711 mm Hg). A continuous vacuum unit in the HTST system may consist of one or two chambers and be heated by Hve steam, with an equivalent release of water by evaporation, or flash steam to carry off the volatiles. If Hve steam is used, it must be cuUnary steam which is produced by heating potable water with an indirect heat exchanger. Dry saturated steam is desired for food processing operations. [Pg.359]

Control of trav and compartment equipment is usually maintained by control of the circulating-air temperature (and humidiy) and rarely by solids temperature. On vacuum units, control of the absolute pressure and heating-medium temperature is utihzed. In direct dryers, cycle controllers are frequently employed to vary the air temper-... [Pg.1190]

Cracking imposes an additional penalty in a vacuum unit in that it forms gas which cannot be condensed at the low pressures employed. This gas must be vented by compressing it to atmospheric pressure. This is accomplished by means of steam jet ejectors. Ideally, it would be possible to operate a vacuum pipe still without ejectors, with the overhead vapors composed only of steam. In practice, however, leakage of air into the system and the minor cracking which occurs make it necessary to provide a means of removing non-condensibles from the system. In addition to the distillation of atmospheric residuum, the lube vacuum pipe still is also used for rerunning of off specification lube distillates. [Pg.217]

Cracking imposes an additional penalty in a vacuum unit in that it forms gas which carmot be condensed at the low pressures employed. This gas must be vented by compressing it to atmospheric pressure. This is accomplished by means of steam jet ejectors. [Pg.76]

The chapter on Compression in Volume 3 of this series presents details of several mechanical vacuum units, and this information will not be repeated here. However, more specific vacuum units and system related data is given. [Pg.382]

In some instances the baffle spacing must be rearranged to allow for a nozzle or coupling connection, ft is important that changes in baffle location be reviewed, as performance or pressure drop can be seriously affected. This is of extreme importance in vacuum units. Baffle orientation is sometimes misinterpreted by the fabricator, and this can cause serious problems where liquid drainage is concerned, or the revised vapor flow path can allow for bypassing the tube surface. [Pg.50]

The feed is first preheated by exchange with the products, charged to the vacuum unit heater, and then passed to the vacuum tower in an atmosphere of superheated steam. Using superheated steam is important it... [Pg.51]

Caustic that is added downstream of the crude oil desalter. Caustic is injected downstream of the desalter to control overhead corrosion. Natural chloride salts in crude decompose to HCl at typical unit temperatures. Caustic reacts with these salts to form sodium chloride. Sodium chloride is thermally stable at the temperature found in the crude and vacuum unit heaters. This results in sodium chloride being present in either atmospheric or vacuum resids. Most refiners discontinue caustic injection when they process residue to the FCC unit. It can still be present in purchased feedstocks, however. [Pg.67]

A test run is conducted to evaluate the performance of a 50,000 bpd (331 m /hr) FCC unit. The feed to the unit is gas oil from the vacuum unit. No recycle stream is processed however, the off-gas from the delayed coker is sent to the gas recovery section. Products from the unit are fuel gas, LPG, gasoline, LCO, and decanted oil (DO). Tables 5-2 and 5-3 contain stream flow rates, operating data, and laboratory analyses. The meter factors have been adjusted for actual operating conditions. [Pg.147]

The Standard-Messo turbulence crystalliser, Figure 15.18, is a draught-tube vacuum unit in which two liquor flow circuits are created by concentric pipes an outer ejector... [Pg.858]

The atmospheric bottom, also known as reduced oil, is then sent to the vacuum unit where it is further separated into vacuum gas oil and vacuum residues. Vacuum distillation improves the separation of gas oil distillates from the reduced oil at temperatures less than those at which thermal cracking would normally take place. The basic idea on which vacuum distillation operates is that, at low pressure, the boiling points of any material are reduced, allowing various hydrocarbon components in the reduced crude oil to vaporize or boil at a lower temperature. Vacuum distillation of the heavier product avoids thermal cracking and hence product loss and equipment fouling. [Pg.10]

The atmospheric crude unit separates crude oil into several fractions including LPG, naphtha, kerosene, gas oil and residues. The heavy residues are then sent to the vacuum unit where they are further separated into vacuum gas oil and vacuum... [Pg.99]

Figure 7.7 Research clinical prototype for laser ablation and vacuum extraction of interstitial fluid, (a) Alignment ring with energy-absorbing dye, (b) laser porator, (c) low-pressure, continuous vacuum unit, (d) harvesting head, and (e) 1 mL insulin syringe. Reprinted with permission from Ref. 12. Copyright 2006 Mary Ann Liebert, Inc. publishers. Figure 7.7 Research clinical prototype for laser ablation and vacuum extraction of interstitial fluid, (a) Alignment ring with energy-absorbing dye, (b) laser porator, (c) low-pressure, continuous vacuum unit, (d) harvesting head, and (e) 1 mL insulin syringe. Reprinted with permission from Ref. 12. Copyright 2006 Mary Ann Liebert, Inc. publishers.
Entrainment is kept at a minimum by a wash oil section in the vacuum unit and checked with a colour specification on the FCC feed. The "real" FCC resid cracking seems to start, when the wash oil stream in the vacuum column is also routed to the FCC unit, obviously the colourof the FCC feed will deteriorate strongly. [Pg.324]

The most cited silica deuteration study was performed by Davydov and co-workers.15,24,25,49 A known amount of D20 vapour was contacted with silica in a vacuum unit with circulation of vapours.50 The silica used for deuteration was pretreated at temperatures ranging from 298 to 473 K. Reaction was performed at room temperature with subsequent evacuation at 473 K. From a mass spectrometrical analysis of the produced vapours, a quantitative measure of the number of surface hydroxyl groups (a0n) was obtained, this quantity will be discussed in chapter 6. [Pg.69]

The temperatures of the sample inside the reactor and of the heating element in the furnace are controlled by thermocouples with an accuracy of +1°C. Low-temperature measurements are performed by submersion of the reactor into the Dewar flask with liquid nitrogen (T = 77 K). The vacuum system has been assembled on a basis of the universal vacuum unit VUP-5. [Pg.369]

It is ironic that the first term torr, from Torricelli, and the later term Pascal, from the mathematician by the same name, were both selected as terms for vacuum units since neither man was really fundamental in vacuum history. Important yes, but not fundamental. [Pg.328]

Atmospheric distillation is least effective in converting heavier products into lighter components. A second distillation column under vacuum is needed to further separate the heavier parts of crude oil into lighter fractions. Some fractions from the vacuum units have better quality than atmospheric distillation cuts because the metal-bearing compounds and carbon-forming materials are concentrated in the vacuum residue. [Pg.820]

For naphthenic acid containing hydrocarbons (Table A-4) where the neutralization number of the feed exoeeds 2 mg of KOH/g in a crude unit or 0 5 mg of KOH/g In a vacuum unit, use type 316L (UNS S31603) SS (2.5% Mo minimum) above 450°F (23°C) regardless of sulfur content. For castings, 316 (CF8M) with 2.5% Mo minimum may be used provided the ferrite content is 8% minimum. [Pg.152]

A process column separates side reaction low boilers from the diol, which is then recycled back to the reaction. Spray condensers and vacuum units recover unreacted feedstock and recycle the diol, thus improving the economics of this process. [Pg.143]

The absorption spectra of the dyes were measured with a Shimadzu UV-3101 PC spectrophotometer (Japan) in a cell with a 1-cm optical path length. The fluorescence and fluorescence excitation spectra were studied with the use of a Shimadzu RF-5301 PC spectrofluorimeter. To study the triplet state of the dyes, apparatuses of flash photolysis with xenon lamp excitation (with an energy of 50 J and a pulse length at half maximum of xi/2 = 7 ps) [6] was used. To detect the triplet state of the dyes, the solutions were deoxygenated using a vacuum unit or purged with argon for experiments on the laser flash photolysis apparatus. A... [Pg.66]

Redirect sour water stripper vent gas from flare to sulfur plant Use gas from crude vacuum unit as fuel rather than as flare Adjust process conditions to reduce flare gas generation FCU... [Pg.356]

A demister is sometimes installed at the top of the scmbber ahead of the vacuum unit, to reduce liquid carryover of small oil droplets, which would otherwise end up in the water from the barometric condenser or in the condensate from the cold (or dry) condensers. [Pg.2779]

The pressure in the deodorizer is always slighlty higher (0.5-1.5 mbar) than on the suction side of the vacuum unit, because of pressure losses caused by the oil demisters, the fatty matter scrubbers, and other equipment. Consequently, to reach an effective deodorization pressure of 2 mbar, a pressure of not more than 1.5 mbar at the suction side is required. To obtain an efficient steam sublimation at this low pressure, special stripping steam condensers operating at extremely low temperatures (—30°C) are required. (Table 19). [Pg.2781]


See other pages where Vacuum units is mentioned: [Pg.70]    [Pg.410]    [Pg.38]    [Pg.243]    [Pg.534]    [Pg.80]    [Pg.271]    [Pg.858]    [Pg.8]    [Pg.66]    [Pg.150]    [Pg.120]    [Pg.6]    [Pg.7]    [Pg.47]    [Pg.439]    [Pg.307]    [Pg.47]    [Pg.243]    [Pg.7]    [Pg.2752]    [Pg.2778]   
See also in sourсe #XX -- [ Pg.74 , Pg.75 ]




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Back vacuum distillation unit

Boiling vacuum distillation unit

Columns vacuum distillation unit

Component vacuum distillation unit

Crude vacuum distillation unit

Feed vacuum distillation unit

Flash vacuum distillation unit

Flow vacuum distillation unit

Hydrocarbons vacuum distillation unit

Light vacuum distillation unit

Mass vacuum distillation unit

Model vacuum distillation unit

Operating vacuum distillation unit

Plant vacuum distillation units

Pressure vacuum distillation unit

Process vacuum distillation unit

Product vacuum distillation unit

Quality vacuum distillation unit

Results vacuum distillation unit

Separators vacuum distillation unit

Steam vacuum distillation unit

Temperature vacuum distillation unit

The statutory units used in vacuum technology

Thermal vacuum distillation unit

Vacuum distillation unit

Vacuum distillation unit schematics

Vacuum frame units

Vacuum once-through units

Vacuum process development unit

Vaporization vacuum distillation unit

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