High vessels

As well as the normal addition reaction, an extremely exothermic decomposition reaction may occur, particularly at high vessel loadings. At loadings of 0.8 ml of 1 1 mixture per ml, the violent reaction, catalysed by iron(III) chloride, initiates at —40°C and will attain pressures above 0.7 kbar at the rate of 14 kbar/s. At 0.5 ml loading density, a maximum pressure of 68 bar, attained at 114 bar/s, was observed. 

The concentration of solids in the upper lean region can be reasonable represented by an exponential decay function which starts from the value in the lower region and falls to the limiting value in an infinitely high vessel. This is the value for pneumatic conveying. 

Multiplying this number with the term ZJd, where Z is the fixed-bed length, we obtain the vessel Peclet number. A high vessel Peclet number means better flow quality, thus closer to ideal flow. Typically, if this number is higher than about 100, the flow is considered to be ideal (plug flow). 

Nickel-plated copper vessels were used in all radiolysis experiments. The vessels were made from copper tubing, 1.5 inches in diameter. The bottom was a 1-mm. thick copper sheet which was silver soldered to the approximately 10-cm. high vessel. A Hoke brass valve with Teflon seat and phosphorus bronze bellows was attached to the top of the vessel by a 1/4-inch Swagelock fitting. Each vessel and all parts of the valves were nickel plated. 

Like all other cooling crystallizers, this unit can only be used to advantage when the solute shows an appreciable reduction in solubility with decrease in temperature. Examples of some of the salts that can be crystallized in this manner are sodium acetate, sodium thiosulphate, saltpetre, silver nitrate, copper sulphate, magnesium sulphate and nickel sulphate. Bamforth (1965) reports the production of 7 ton/day of 10 x 5 mm sodium thiosulphate crystals in a 2 m diameter 6 m high vessel with 200 m heat exchange surface. 

The main sodium tank holds some 560,000 gal of sodium. During normal operation, the tank sodium will be at the reactor inlet temperature of 800°F. During refueling, the temperature will be 350°-400°F. The tank is a 1-in. thick, 52-ft-diam by 47-ft-high vessel. The tank structure would be built to withstand about 10 psig. 

Calculate the pressure produced by water (62.4 lb) in a 6-ft high vessel. 

Gas-tight, 65-mil (61ST) aluminum cylindrical tank, 32.2 cm in diameter and 76 cm high. Vessel has a 1-in. glory hole on the horizontal center line and appropriate control rod thimbles. Tank contains core fuel discs and graphite reflector plugs. 

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