Jacketed tank

A stable crystalline form for chocolate depends primarily on the method used to cool the fat present in the Hquid chocolate. To avoid the grainy texture and poor color and appearance of improperly cooled chocolate, the chocolate must be tempered or cooled down so as to form cocoa butter seed crystals (31). This is usually accompHshed by cooling the warm (44—50°C) Hquid chocolate in a water jacketed tank, which has a slowly rotating scraper or mixer. As the chocolate cools, the fat begins to soHdify and form seed crystals. Cooling is continued to around 26—29°C, during which time the chocolate becomes more viscous. If not further processed quickly, the chocolate will become too thick to process. 

The fluidfoil impellers (shown in Fig. 18-2) usually give more flow for a given power level than the traditional axial- or radial-flow turbines. This is also thought to be an advantage since the heat-transfer surface itself generates the turbulence to provide the film coefficient and more flow should be helpful. This is true to a limited degree in jacketed tanks (Fig. 18-34), but in helical coils (Fig. 18-35), the... 

Examples of Vacuum-Related Accidents Figure 26-47 shows a jacketed tank, where the jacket was designed for low-pressure steam. When the steam was turned off and the drain valve and trap were closed, the steam condensed, causing the jacket to collapse. The jacket should have been designed for full vacuum, or a suit le vacuum relief device should have been installed on the jacket. 

LNG tanks use low pressure (less than 5 psi), yet need double-wall construction so that insulation between the walls keeps the LNG cool. For the large tanks, a cylindrical design with a domed roof is used, but for smaller quantities (70,000 gallons or less), storage is in horizontal or vertical vacuum-jacketed tanks at pressures any where from less than 5 psi to over 250 psi. 

The basic mix is made up in liquid form, pasteurized, homogenized and cooled, using chilled water in plate heat exchangers. It is then aged for a few hours and, for this, it will be stored at 2-3°C in jacketed tanks, with chilled water in the jacket. 

Jacketed tank reactors, mainly stainless steel reactors and glass-lined reactors equipped with a stirrer, predominate in plants for the manufacture of fine chemicals. Glass-lined reactors are in common use although they are by 30-50 % more expensive than stainless steel reactors. This is because of the high chemical resistance of enamels towards typical chemical media and the much lower possibility of contamination of products with heavy metals, which should not be... 

This is the simplest type of industrial crystallising equipment. Crystallisation is induced by cooling the mother liquor in tanks which may be agitated and equipped with cooling coils or jackets. Tank crystallisers are operated batchwise, and are generally used for small-scale production. 

Therefore, even a moderate error in the mixer scale-up will have only a small effect on the agitator-side heat transfer coefficient. Other factors that include heat transfer area per unit volume are considerably more significant. For instance, in the jacketed tank, the heat transfer area per unit volume decreases upon scale-up. In order to assure the same proportionate heat removal or addition per unit batch size, additional heat transfer area (e.g., coils) may be required. Additionally, other variables such as temperature driving force may have to be adjusted to compensate for decreased heat... 

Load 86.8 g propylene glycol into a glass-lined or suitable stainless steel-jacketed tank. 

Adjust flow rate such that the temperature rise of the suspension does not exceed 10°C. Collect the milled suspension in a stainless steel-jacketed tank with vacuum. Mix at 25° to 30°C under vacuum until a uniform suspension is achieved. 

Charge 285 mL purified water into a suitable jacketed tank and heat to 90° to 95°C. 

Charge glycerin and 210 mL purified water into a stainless steel-jacketed tank. 

Load 780 g (portion of item 2) of sorbitol solution into a stainless steel-jacketed tank. Remaining sorbitol to be used later. 

Charge 950 g sorbitol solution in a stainless steel-jacketed tank and heat to 95° to 100°C. 

Values of overall coefficients of heat transfer are collected in Tables 17.10-17.12. Two sets of formulas for tank-side film coefficients are in Tables 17.13 and 17.14. They relate the Nusselt number to the Reynolds and Prandtl numbers and several other factors. In the equation for jacketed tanks, for example,... 

Does the process require a jacketed tank to heat the product ... 

Refrigeration. At least one major winery minimizes the amount of wine movement necessary by cold stabilizing the wine at 28° F (-2.22° C) in a jacketed tank until laboratory evaluation shows the wine to be cold stable. The wine is allowed to warm to 30°-32° F (-1. ll°-0° C), then a slurry of bentonite, which has been soaked at least overnight in hot water, is added to the wine at the level prescribed by the previously described laboratory procedure. When the bentonite has settled to the bottom of the tank, the wine is racked off the bentonite lees and filtered to a holding tank. The wine is now ready for polish filtration and bottling. 

Compute the process-side heat-transfer coefficient. The correlations for inside (process-side) heat-transfer coefficient in an agitated tank are similar to those for heat transfer in pipe flow, except that the impeller Reynolds number and geometric factors associated with the tank and impeller are used and the coefficients and exponents are different. A typical correlation for the agitated heat-transfer Nusselt number (ANu = htT/k) of a jacketed tank is expressed as... 

Portable Melter-Mixers for Foam Precursor Preparation. The melter-mixers assembly (Figure 6) consists of a 1500-gal tank and a 800-gal tank having a capacity of 18,000 and 9,600 lb per batch, respectively. These jacketed tanks are equipped with stirrer, filters, circulating... 

Several approaches were used for the temperature control, for example, heating of the lines, pumps, valves mixing head, etc., by electrical resistance heating by means of heating cartridges and tracing lines, as well as by the recirculation of heated oil through jacketed tanks and lines. The methods used depend on the specific requirements of the application and the complexity of the machines. 

The cost of a fermenter with helical coils is cheaper than a jacketed tank with internal coils. 

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