Heat vessels/piping elements

Bayonet Heaters A bayonet-tube element consists of an outer and an inner tube. These elements are inserted into tanks and process vessels for heating and cooling purposes. Often the outer tube is of expensive alloy or nonmetalhc (e.g., glass, impeivdous graphite), while the inner tube is of carbon steel. In glass construction, elements with 50.8- or 76.2-mm (2- or 3-in) glass pipe [with lengths to 2.7 m (9 ft)] are in contact with the external fluid, with an inner tube of metal. 

A calibrated water tank was used to measure the water input to the steam generator. Both the water and inert gas rates were measured by rotometers. Heat input to the gas and water was maintained by voltage control of resistance elements in the heaters, permitting remote control of temperature levels. Thermocouples were located on all test components and interconnecting piping. Pertinent temperatures in the reaction vessel and gas streams were measured by iron-con-stantan thermocouples. 

Separation processes typically consist of hrmdreds of elements (pipes, vessels, heat exchangers, columns, pumps, compressors, engines, measuring and control devices, etc.) that are too complex for exact graphical depiction. Therefore, the process structures are depicted in a very abstract and geometrically nonsimilar manner in the form of flow sheets. Flow sheets show the process structure with symbols for the essential process elements according to international standards (e.g., DIN, ISO). 

Heat from spherical fuel elements is transferred by natural convection of the molten salt coolant in the riser to the salt-aif heat exchangers, where, in turn, it is transferred to the environmental air serving as a working medium of the secondary circuit. The molten salt coolant never exits the vessel boundary. Heated air is directed to the gas-turbine unit through the pipes located on the cover of the reactor mono-block. 

A step-by-step analysis is given for the direct computation of 2D heat flow and safe pitching of the cooling pipes. Two models of the cooling system have been selected and calculations have been carried out for an existing vessel. On the one model this analysis is compared with the 3D finite-element analysis for obtaining insulation conductance for various cooling pipes. A safety factor is established. 

---