Internally cooled

Different cooling concepts are used for the adjustment of the heatbalance in the blades. Illustration 2a shows a hollowpoured turbine blade with complex internal cooling structure. 

Electrolysis cell. This is shown in Fig. VI, 31, 1 and is almost self-explanatory. The cylindrical cell of Pyrex glass (6" long by 2 " diameter) is cooled by immersion in a cooling bath. The electrodes consist of two platinum plates (4 cm. X 2-5 cm. X 0-3 mm.), which are placed about 2 mm. apart. The temperature of the electrolyte is maintained at 30-35° by means of the internal cooling coil and also by immersion of the cell in ice-water. A current of 1 5-2 0 amperes is passed until the electrolyte becomes slightly alkaline, which normally takes about 20-50 per cent, longer than the calculated time on the basis of the current and the amounts of acid employed. It is advantageous to reverse the direction of the current occasionally. 

Injection molds are constmcted of metal precision-machined with internal cooling, multiple cavities, and multifaces, and with devices for extraction... 

Process. A typical indirect hydration process is presented in Eigure 1. In the process, propylene reacts with sulfuric acid (>60 wt%) in agitated reactors or absorbers at moderate (0.7—2.8 MPa (100—400 psig)) pressure. The isopropyl sulfate esters form and are maintained in the Hquid state at 20—80°C. Low propylene concentrations, ie, 50 wt %, can be tolerated, but concentrations of 65 wt % or higher are preferred to achieve high alcohol yields. Because the reaction is exothermic, internal cooling coils or external heat exchangers are used to control the temperature. 

Environment Internal Cooling water near ambient temperature, intermittent low flow, daily chlorination for 1 hour... 

Environment Internal Cooling water containing neutralizing amine, oxygen scavenger, caustic... 

Environment Internal Cooling water phosphonate and zinc water treatment... 

Environment Internal Cooling water treated with phosphate, dispersant, and bleach temperature 70-100°F (21-38°C), pH 6.S-7.2... 

Environment internal Cooling water, pH 8.6, all organic treatment External Freon refrigerant... 

Environment Internal Cooling water phosphate, zinc, and polymer treatment, 70°F (21 °C)... 

Environment Internal Cooling water treated with scale inhibitor External Refractory... 

Environment Internal Cooling water treated with corrosion inhibitors and sodium hypochlorite biocide, 75°F (24°C), 50 psi (345 kPa), pH 7-8... 

Environment Internal Cooling water External Steam and condensate... 

LEC 60034-6 has specified a number of probable cooling systems, as adopted by various manufacturers. The more commonly used practices are shown in Table 1.12. According to this specification any cooling system may be expressed by the letters IC (international cooling) followed by... 

However, in certain cases, the impingement plate design is preferred over packed-tower columns when either internal cooling is desired, or where low liquid flow rates would inadequately wet the packing. 

If the temperature rise over the temperature range is very high, then to operate at constant temperature requires internal cooling coils in the column, or other means of heat remo al to maintain constant temperature operation. Usually this condition will require considerably less transfer imits for the same conditions when compared to the adiabatic operation. 

The usual centrifugal compressor is uncooled internally, and hence, operates with polytropic characteristics having n greater than k however, if the unit is internally cooled, then n will be greater than 1.0 but may be less than k. The inefficiencies caused by internal losses (friction, etc.) keep the operation from being truly adiabatic however, some compressions are close to this condition and may be used for approximations. 

A mixture of a 4-azidopyridine (0.9-1.0 g), 28% NaOMe/MeOH (10 mL. large excess), MeOH (65 mL) and dioxane (75 mL) was irradiated under N2 with a 400-W high-pressure Hg lamp equipped with a Pyrex filter, the apparatus being internally cooled with running water. When TLC showed that all starting material had been consumed (3 4 h), the solvents were distilled off under reduced pressure and the residue was treated with ice-water (30-50 mL). The aqueous mixture was extracted with hexane or benzene and the dried extract was evaporated in vacuo, leaving the product as an oil, which was purified by chromatography (Scphadex or silica gel, benzene). 

The internal cooling system was applied to the Fischer-Tropsch process by the U. S. Bureau of Mines (48, 49), the British Fuels Board (54), and Rheinprussen-Koppers (52, 53). The external cooling system was applied to the Fischer-Tropsch process by I. G. Farben (61). 

A schematic drawing is shown in Fig. 14. Two "prepoly CSTR s in parallel, each with a 1400-kg. holduo, fed a total of 44 kg./hr. of syrup at 80 C and 33-35% conversion to a second-stage LFR. The CSTR s were cooled via jackets and internal cooling coils, and slowly agitated with gate-type agitators. 

The micro bubble column comprises internal cooling via heat conduction from the reaction zone to a mini channel heat exchanger [3, 9, 10], Either two such heat exchange plates can encompass the reaction plate, or only one. In the latter case, the free position is occupied by an inspection window which allows direct observation of the quality of the flow patterns. 

By operating in this mode, the necessity for using heat exchangers is eliminated or minimized. If one regards the exit temperature of 181 °C as excessive, a heat exchanger could be used between the CSTR and the PFR, or arrangements could be made for internal cooling within the PFR. 

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