Liquid space

Fluidization Vessel The most common shape is a vertical cylinder. Just as for a vessel designed for boiling a liquid, space must be provided for vertical expansion of the solids and for disengaging... 

In the more general and more difficult case, either the punc ture is initially in the liquid space, or in a line attached to it, or the liquid swells to reach the punc ture or punc tured line, giving two-phase or all-liquid discharge. For these cases the discharge model solutions must treat four regimes, which are defined by the initial void (vapor) frac tion Ot and by the pressure ratios ... 

Regime 1. If the tank is initially saturated (usually pressurized with volatile contents) there is no padding gas contributing noncon-densables, so Tj, = 1 and Ot, = 0. In this case, a discharge in the liquid space is a flashing hquid. 

Proper condensate removal is important. An inverted split cup inside the shell, with the upper capped end above the nozzle and the lower open end -in. above the bottom tubesheet, should be used to cover the oudet nozzle. This can be made by splitting a pipe that is one size larger than the condensate oudet down the centerline. In this case, a 2-in. split is adequate. This cup must be fully seal welded (not tack welded) to force condensate down to the -in. clearance above the bottom tubesheet. A common error is to allow 6 in. or more above the tubesheet for the centerline of the condensate oudet. In this case, 6 in. of tube is 10% of the surface. If the cup is not used, add 10% more tubes to correct for the dead liquid space near the bottom. This is in addidon to the 10% safety factor. 

Catalyst temperature, flush liquid, space velocity SO2 removal in 190 mm deep bed (%) Bed depth for 95% S02 removal (m) Pressure drop at 95% S02 removal (kPa)... 

A puncture in the liquid space of the vessel or a break in the bottom-attachment or dip-leg pipe, initially, at least, discharges liquid plus any solids present without any noncondensable components. The liquid can begin to flash when the pressure drops to the bubble point pressure Pbub. If the liquid is extremely volatile, it could totally evaporate when the pressure drops below the dew point, producing vapor plus solids. The initial mass vapor fraction Xo is zero as is the initial volume fraction (Xq. 

Typically a BLEVE occurs after a metal container has been overheated above 538 °C (1,000 °F). The metal may not be able to withstand the internal stress and therefore failure occurs. The contained liquid space of the vessel normally acts as a heat absorber, so the wetted portions of the container are usually not at risk, only the surfaces of internal vapor spaces. Most BLEVEs occur when containers are less than 1/2 to 1/3 full of liquids. The liquid vaporization expansion energy is such that container pieces have been thrown as far as 0.8 km (1/2 mile) from the rupture and fatalities from such incidents have occurred up to 244 meters (800 ft.) away. Fireballs may occur at the time of rupture, that are several meters in diameter, resulting in intense heat exposure to nearby personnel. Fatalities due to burns from such incidents have occurred to personnel as much as 76 meters (250 Ft.) away from the point of rupture. 

Catalysts A, prepared from aluminum isopropoxide and calcined at 700° for 4 hours A—Na, contained 1 % by weight of sodium by impregnation with sodium carbonate A—H, purchased from Harshaw Chemical Company it contained 0.35% of sodium. HLSV = hourly liquid space velocity, grams of alcohol per gram of catalyst per hour. 

Catalyst 5% nickel on silica-alumina Pressure 350 lb./sq. inch gage Liquid space velocity 1.0 vol./vol./hour H2 HC, mole ratio 4.0... 

In view of these considerations, a large amount of effort is reported in the scientific press on the development of a process to produce benzene from n-hexane by combined cyclization and dehydrogenation. w-Hexane has a low Research octane number of only 24.8 and can be separated in fair purities from virgin naphthas by simple distillation. Recently, an announcement was made of a process in the laboratory stage for aromatiza-tion of n-hexane (16). The process utilizes a chromia-alumina catalyst at 900° F., atmospheric pressure, and a liquid space velocity of about one volume of liquid per volume of catalyst per hour. The liquid product contains about 36% benzene with 64% of hexane plus olefin. The catalyst was shown to be regenerable with a mixture of air and nitrogen. The tests were made on a unit of the fixed-bed type, but it was indicated that the fluid technique probably could be used. If commercial application of this or similar processes can be achieved economically, it could be of immense help in relieving the benzene short-age. 

Chlorine gas from a cylinder passes through a flask used as a safety trap and then is condensed in a large test tube (or flask for larger amounts) by surrounding it with a mixture of acetone or ether and solid carbon dioxide. The powdered iodine is added slowly and immediately is converted to flocculent, orange, iodine trichloride which settles gradually. When the liquid space is filled with the trichloride, the excess chlorine is evaporated into a second container where the process may be repeated. 

Let us take a given configuration, in a micro-region of liquid space, denoted by C ,... 

Let C represent the static configuration that resides within the potential in the micro-region of liquid -space i.e., the counterpart to the configuration, ( n(. We know that the relationship exists between the static, C, and the dynamic, C configurations should... 

Algebraic equations (AEs) describe relations among variables of the system which are independent of time or space changes. They represent variables not related by material energy or momentum balances. They may characterize physicochemical or other type of relationships between physically independent portions of the system, as the vapor and liquid spaces of a reaction vessel. 

In the fixed-film reactor, the organisms grow on an inert surface that is maintained in the reactor. The inert surface can be granular material, proprietary plastic packing, rotating discs, wood slats, mass-transfer packing, or even a sponge-type material. The reactor can be flooded or nave a mixed gas-liquid space (Fig. 25-52). The biomass level on the... 

Type of Minimum particle Minimum Approx. Typical gas Maximum Gas pressure Liquid Space no... 

Liquid space surrounding active solid. Particularly in heterogeneous reaction system involving a liquid medium, thorough examination of the hydrodynamic flow conditions is appropriate. An example will illustrate this point. 

In the study of reaction rates of organic acids with lead (Turnbull and Frey, 6), a solid lead cylinder was rotated at high speeds in a solvent containing the acid. The liquid space in the vessel and velocity of rotation were chosen to yield Reynold s numbers of the order of 12,000 to 60,000, thus definitely creating turbulent flow in the medium. The reaction rates measured in this system were of the order of 10 moles/sec./cm. metal surface. While the bulk of the liquid medium was doubtless in turbulent... 

The reaction conditions were as follows temperature 482 <>C, pressure 520 kPa, liquid space velocity (WHSV) 2 h l, hydrogen to hydrocarbon ratio 3. 

Kinetic tests were carried out In a fixed-bed tubular reactor described elsewhere (ref.10). Reaction conditions were catalyst weight = 5 g total pressure 3 MPa molar ratio Kj/ethylbenzene - 10 liquid space velocity > 3 h and reaction temperature > 523 K. Liquid ethylbenzene (ETB) was diluted with decal in (70 wtX) and 100 ppm of thiophene were added. Reactants and products were analyzed by GLC. 

---