Heat coil-type

Siace dimer acids, monomer acids, and trimer acids are unsaturated, they are susceptible to oxidative and thermal attack, and under certain conditions they are slightly corrosive to metals. Special precautions are necessary, therefore, to prevent product color development and equipment deterioration. Type 304 stainless steel is recommended for storage tanks for dimer acids. Eor heating coils and for agitators 316 stainless steel is preferred (heating coils with about 4s m (50 ft ) of heat transfer surface ia the form of a 5.1 cm schedule-10 U-bend scroU are recommended for a 37. 9-m (10,000-gal) tank. Dimer acid storage tanks should have an iaert gas blanket. 

Many boilers are fitted with a heat exchanger-type water sampling coil that permits the collection of a representative and cooled BW sample. The design generally provides for a coil of copper or stainless steel (SS) fitted inside a small SS shell. The unit is fitted with gate valves to control the flow of cooling water and BW. 

Both types of boiler systems may incorporate finned copper heating coils, which are located above the furnace and gas-pass tubes (smoke tubes or fire tubes) and provide for indirect heating of domestic HW. Where coils are fitted and the boilers are only fired during winter months, domestic HW heating usually is provided via gas heaters for the summer. 

For ice on coil type ice storage tank, water inside the tank is sometimes agitated to enhance heat transfer on coil surface. Small water or air pumps are used for this purpose. This agitation is effective until ice is formed on the coil, because temperature during ice forming is uniformly freezing point. Degree... 

Application of a divided cell containing one pair of electrodes (Pt-coated Ti anode 316 type stainless steel cathode) with an effective area of 100 cm2. Nafion-324 was used as the membrane. Two 81 tanks contained anolyte (feed) and catholyte (caustic). A coil-type heat exchanger was used to maintain the heat... 

A 200-ml. three-necked flask is equipped with a thermometer, a mechanical stirrer, a gas inlet tube extending as far into the flask as the stirrer permits, and a trap (designed to return the heavier layer of the condensate) (Note 1), which is attached to a bulb and a coil-type reflux condenser connected in series. Methyl p-ethylbenzoate (98 g., 0.597 mole) (Note 2) and a mixture of 1 g. of chromium oxide and 4 g. of calcium carbonate, prepared by grinding the solids together in a mortar, are added. An air line with a bleed control valve (Note 3) is connected from the top of the condenser to a water aspirator. The flask is heated with a hemispherical electric mantle (Note 4). 

Figure 5.1 Few common types of heat exchangers, (a) Double-tube type (b) shell-and-tube type (c) coil-type and (d) plate-type.

Adiabatic calorimetry is particularly useful for the study of closed adsorption systems at low temperatures (where radiation losses are small) and for temperature scanning experiments. It is the preferred type of measurement for the determination of the heat capacity of adsorption systems, especially in the temperature range 4-300 K (Morrison et al., 1952 Dash, 1975). The temperature scan is obtained by means of the Joule effect applied to the sample container the sample heating coil shown in Figure 3.14 is used for this purpose. 

Table IX presents heat transfer data for an external catalyst cooler of the FFB type. Heat flux of 70-150 kW/m2 and heat transfer coefficient of 350-490 W/(m2-k) were obtained, both somewhat less than those of a turbulent bed internal cooler (horizontal coil type), but approximately equal to those of the external cooler of the bubbling bed type.

The coiled heat exchanger is very compact, and it is frequendy used when space is limited. The decision between the heat-exchanger types is not as distinct as indicated. At the boundary of each category, a detailed analysis is required to arrive at the most economical choice. Walas [5] discusses other heat-exchanger designs. 

Heat transfer is more of a problem in batch reactors than in other types of equipment because of their small surface-to-volume ratio and because rates are high initially. Effective stirring is essential. If the reaction is highly exothermic or endothermic, cooling or heating coils are usually needed. 

Jacket and Coil Type.—Figure 5 shows the construction of the first multiple-effect evaporator invented and patented by Pecqueur, and the heating surface consists simply of dished copper bottoms. The whole arrangement of the multiple effect is very simple, but naturally the capacity is small as such a construction is always limited in size. Figure 6 shows Howard s vacuum pan with jacket for the concentration of sugar juice. A similar pan was used by Roth for the same purpose. 

Conveying-screen dryers are fabricated with conveyor widths from 0.3- to 4.4-m sections 1.6 to 2.5 m long. Each section consists of a sheet-metal enclosure, insulated sidewalls and roof, heating coils, a circulating fan, inlet air distributor baffles, a fines catch pan under the conveyor, and a conveyor screen (Fig. 12-51). Table 12-23 gives approximate purchase costs for equipment with type 304 staimess-steel hinged conveyor screens and includes steam-coil heaters, fans, motors, and a variable-speed conveyor drive. Cabinet and auxiliary equipment fabrication is of aluminized steel or stainless-steel materials. Prices do not include temperature controllers, motor starters, preform equipment, or auxiliary feed and discharge conveyors. These may add 75,000 to 160,000 to the dryer purchase cost (2005 costs). 

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