A manufacturing facility requires saturated steam at 120°C at a rate of 1.2 kg/min. Design an electric steam boiler for this purpose under these constraints:
• The boiler will be in cylindrical shape with a height to diameter ratio of 1.5. The boiler can be horizontal or vertical.
• The boiler will operate in the nucleate boiling regime, and the design heat flux will not exceed 60 percent of the critical heat flux to provide an adequate safety margin.

• A commercially available plug-in type electrical heating element made of mechanically polished stainless steel will be used. The diameter of the heater cannot be between 0.5 cm and 3 cm.
• Half of the volume of the boiler should be occupied by steam, and the boiler should be large enough to hold enough water for 2 h supply of steam. Also, the boiler will be well insulated. You are to specify the following:

(a) The height and inner diameter of the tank,

(b) The length, diameter, power rating, and surface temperature of the electric heating element,

(c) The maximum rate of steam production during short periods of overload conditions, and how it can be accomplished.

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Boiler