Stripping in distillation

A standard extraction process is one in which the primary purpose is to transfer solute from the feed phase into the extract phase in a manner analogous to stripping in distillation. Fractional ex action... 

The product gases are first cooled below 200°C to selectively condense so-called zirconium tetrachloride snow in a large space condenser. The sihcon tetrachloride subsequendy is condensed in a quench condenser wherein the warm gases are countercurrendy scmbbed with Hquid siUcon tetrachloride at —20° C. The siUcon tetrachloride is purified by stripping and distillation. 

Dilute (1—3%), chloride-containing solutions of either HOCl, hypochlorite, or aqueous base, can be stripped in a column against a current of CI2, steam, and air at 95—100°C and the vapors condensed giving virtually chloride-free HOCl solutions of higher concentration in yields as high as 90% (122—124). Distillation of more concentrated solutions requires reduced pressure, lower temperature, and shorter residence times to offset the increased decomposition rates. 

Condition of Feed (q Fine). The q line, which marks the transition from rectifying to stripping operating lines, is determined by mass and enthalpy balances around the feed plate. These balances are detailed in distillation texts (15). 

For absorption, stripping, and distillation, there are three main steps involved in design ... 

Data on the gas-liquid or vapor-liquid equilibrium for the system at hand. If absorption, stripping, and distillation operations are considered equilibrium-limited processes, which is the usual approach, these data are critical for determining the maximum possible separation. In some cases, the operations are are considerea rate-based (see Sec. 13) but require knowledge of eqmlibrium at the phase interface. Other data required include physical properties such as viscosity and density and thermodynamic properties such as enthalpy. Section 2 deals with sources of such data. 

The design of a plate tower for gas-absorption or gas-stripping operations involves many of the same principles employed in distillation calculations, such as the determination of the number of theoretical plates needed to achieve a specified composition change (see Sec. 13). Distillation differs from gas absorption in that it involves the separation of components based on the distribution of the various substances between a gas phase and a hquid phase when all the components are present in Doth phases. In distillation, the new phase is generated From the original feed mixture by vaporization or condensation of the volatile components, and the separation is achieved by introducing reflux to the top of the tower. 

Figure 14-6 illustrates the graphical method for a three-theoretical-plate system. Note that in gas absorption the operating line is above the equihbrium curve, whereas in distillation this does not happen. In gas stripping, the operating line will be below the equihbrium curve. 

Solvents are recovered from the oil stream through distillation and steam stripping in a fractionator. The stream extracted from the solvent contains high concentrations of hydrogen sulfide, aromatics, naphthenes and other hydrocarbons, and is often fed to the hydrocracking unit. 

Certain refinery wastewater streams are treated separately, prior to the wastewater treatment plant, to remove contaminants that would not easily be treated after mixing with other wastewater. One such waste stream is the sour water drained from distillation reflux drums. Sour water contains dissolved hydrogen sulfide and other organic sulfur compounds and ammonia which are stripped in a tower with gas or steam before being discharged to the wastewater treatment plant. 

The heated oil is flashed into the VPS flash zone where vapor and liquid separate. Split between distillate and bottoms depends on flash zone temperature and pressure. Separation of vapor and liquid in the flash zone is incomplete, since some lower boiliug sidestream components are present in the liquid while bottoms components are entrained in the vapor. The liquid from the flash zone is steam stripped in the bottom section of the VPS to remove the lower boiling components. 

The packed column has been quite useful in distillation, stripping, and absorptions processes and has become competitive tvith many types of distillation tray designs or types/styles. 

Ni-Si recovery of HP Processes involving cone. H2SO4 processes. Sulphur stripping columns. Distillation columns containing acidic chlorides. Handling acid sludges processes impellers, propeller shafts, fasteners. Demisters in desalination plants refrigerating brines. Salt production. Evaporators steel... 

At 220°C a water-paraffin mixture is distilled off in a circulating evaporator (8). The product mixture passes to a second circulating evaporator (9) where the paraffin is stripped at 270°C with overheated water vapor, and finally the paraffin content in the resulting alkanesulfonate melt is further reduced by vapor stripping in a packed column (10). A heat transfer oil dissipates excess heat. 

Apply emulsion of choice, e.g., Amersham LM-1, Ilford KS, Kodak NTB2 diluted l lv/v in distilled H20 or apply Kodak AR10 Stripping Film. 

Petroleum distillation units generate considerable wastewater. The process water used in distillation often comes in direct contact with oil and can be highly contaminated. Both atmospheric distillation and vacuum distillation produce an oily, sour wastewater (condensed steam containing hydrogen sulfide and ammonia) from side-stripping fractionators and reflux drums. 

Many processes in a refinery use steam as a stripping medium in distillation and as a diluent to reduce the hydrocarbon partial pressure in catalytic or thermal cracking [37]. The steam is eventually condensed as a liquid effluent commonly referred to as sour or foul water. The two most prevalent pollutants found in sour water are H2S and NH3 resulting from the destmction of organic sulfur and nitrogen compounds during desulfurization, denitrification, and hydrotreating. Phenols and cyanides also may be present in sour water. 

Raw material recovery can be achieved through solvent extraction, steam-stripping, and distillation operations. Dilute streams can be concentrated in evaporators and then recovered. Recently, with the advent of membrane technology, reverse osmosis (RO) and ultrafiltration (UF) can be used to recover and concentrate active ingredients [14]. 

Clean each polished stainless steel strip (or any surface to be treated) with detergent and rinse well with distilled water. Spot-inoculate four steel strips with a known volume of a culture for each dilution of sanitizer. Each strip should contain approximately 100 organisms. Allow drying for 30 min at room temperature. After drying, immerse two strips in sanitizer solution to be tested. Allow the contact for 5, 10, or 15 min. 

The amine (0.1 mole) is dissolved in a buffered (pH 4-5) solution of 500 ml of 60 % aqueous acetic acid and 68 gm of sodium acetate. The reaction mixture is warmed to 90°C. Then 69 gm (1.0 mole) of sodium nitrite dissolved in 100 ml of water is added dropwise over a 45 min period while heating at 90°C is continued. After the addition, the reaction mixture is heated for 2 hr, cooled, poured into 200 ml of cold water, and extracted three times with 200 ml portions of ether. The ether was washed with 10 % potassium carbonate solution until basic, then with saturated sodium chloride solution, dried, stripped, and distilled to obtain the products shown in the table. 

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