Cooling and stabilizers

One hundred milliliters of a 0.001% solution of tetrachloroauric (III) acid (or silver nitrate) in distilled water ia treated with several drops of 1% sodium carbonate 10-hydrate and heated to boiling in a flask. Every 30 seconds one drop of a fresh 1% tannin solution (XJ.S.P.) is added with agitation. When a deep red gold color has formed (or yellow-brown to red-brown for the silver) the colloidal solution is cooled and stabilized by the addition of a few milliliters of chloroform or toluene. 

Once the optimum operating conditions are established, individual runs can be quite short, depending upon the retention time at which enantiomers elute, from 10 to 100 min. Most enantiomers of interest can be made to elute in <30 min when a single oven system is used. The instrument has to be cooled and stabilized before another run can be carried out, so the total time from one run to the next will be -1 hr. The run time will depend mostly upon the temperature program. 

In the process (Figure 9-12), the feedstock (a vacuum residuum) is mixed with recycle vacuum residue from downstream fractionation, hydrogen-rich recycle gas, and fresh hydrogen. This combined stream is fed into the bottom of the reactor whereby the upward flow expands the catalyst bed. The mixed vapor liquid effluent from the reactor, either goes to flash drum for phase separation or the next reactor. A portion of the hydrogen rich gas is recycled to the reactor. The product oil is cooled and stabilized and the vacuum residue portion is recycled to increase conversion. 

NASA is also considering a more advanced aircraft such as Mach 5 to cut Pacific travel time to about three hours, but in this case kerosene fuel is no longer acceptable, and liquefied natural gas or liquefied hydrogen would be needed to provide the necessary cooling and stability. However, a completely new fueling system would be required at every international airport to handle these cryogenic fluids. 

Immediately upon extrusion from the die, the film tube is expanded by internal air pressure, which is supplied by air fittings and controls in the center of the die. An air ring may be used on the die to control the cooling and stabilize the semi-molten LCP film tube. The driven pinch rollers are controlled so that the total take-up speed will produce stretching, or draw, in the machine direction. 

Measurement of the density of smoke evolved from a burning or smouldering specimen has been widely studied and several tests proposed. They differ mainly in that some measure the density of hot smoke as evolved from the specimen, while others allow the smoke to cool and stabilize before density is measured. Other tests use a gravimetric method for smoke determination. 

A modern day blown film process is shown in Figure 6.16. Based on the shape of the bubble as the molten polymer exits the die, this line is processing LLDPE. Advanced designs are utilized to cool and stabilize the bubble (referred to as a Bubble Cage) at high line rates to form films of a uniform thickness. Single to multilayer films are possible. 

The autoclave is filled with monomer in a water mix and a catalyst is added. Heating is applied by the TIC loop until reaction starts to occur and the process becomes exothermic. The TIC loop applies cooling and stabilizes the temperature of the contents over a period of several hours as the contents convert to polymer. 

Organophosphoms compounds, primarily phosphonic acids, are used as sequestrants, scale inhibitors, deflocculants, or ion-control agents in oil wells, cooling-tower waters, and boiler-feed waters. Organophosphates are also used as plasticizers and flame retardants in plastics and elastomers, which accounted for 22% of PCl consumed. Phosphites, in conjunction with Hquid mixed metals, such as calcium—zinc and barium—cadmium heat stabilizers, function as antioxidants and stabilizer adjutants. In 1992, such phosphoms-based chemicals amounted to slightly more than 6% of all such plastic additives and represented 8500 t of phosphoms. Because PVC production is expected to increase, the use of phosphoms additive should increase 3% aimually through 1999. 

Pre-liming. Lime slurry, 0.25% lime on juice (0.250 g of CaO/100 g juice), is added to bring the pH of the mixture into the alkaline range. Insoluble calcium salts are precipitated as finely dispersed coUoids. Calcium carbonate in the form of recycled first carbonation sludge is added to provide coUoid absorption and stabilization. Temperature may be cool (50°C) or hot (80°C) depending on the temperature of the next step, or occasionally on the type of diffusion equipment. Retention time is 15 to 30 min. 

On the other hand, this type of cooling permits the study of increasing or decreasing temperature profiles in the jacket and their influence on the inner temperature profile, reactor performance, and stability. For this type of study a reactor tube is needed that is large enough to accommodate an inner thermowell holding a multiple thermocouple assembly. 

Generally the substances in this class are unstable when heated or exposed to light they should be stored cool and in the dark. However, for liquids with added stabilizer cooling may cause separation of the material from the stabilizer. Similarly, precipitation of a potentially explosive compound from a diluent may occur on cooling. In both cases this can represent a hazardous situation. 

Film generated by depositing a layer of liquid plastic onto a surface and stabilizing by evaporating the solvent, by fusing after deposition or by cooling. Cast films are generated from solutions or dispersions. 

The chromatogram is freed from mobile phase (stream of warm air, 15 min), immersed for 2 s in the reagent solution after cooling to room temperature and heated to 110— 120°C for 10—20 min. The chromatogram is then briefly immersed in liquid paraffin — n-hexane (1 + 6) in order to enhance and stabilize the fluorescence. 

Teflon support with its glass side facing the gas inlet the autoclave was evacuated (10 min, < 1 mbar), carefully filled with HCl gas (1 bar) and heated to 110°C for 15 min. After opening the autoclave the HCl vapors were blown out with a stream of cold air (5 min) and the HPTLC plate was cooled to room temperature. In order to intensify and stabilize the fluorescence the plate was dipped in a solution of liquid paraffin in chloroform (30 + 70) for 15 s. 

Detection and result The chromatogram was dried in a stream of cold air and then intensively irradiated with UV Ught (A = 365 nm) for 2 min and then immersed in the reagent solution for 1 s. It was finally heated to 120°C for 10 min and after cooling dipped into hquid paraflln — n-hexane (1 2) to intensify and stabilize... 

Figure 6-3 shows a condensate stabilizer system. The well stream flows to a high pressure, three-phase separator. Liquids containing a high fraction of light ends are cooled and enter the stabilizer tower at approxi-... 

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