GEOMETRY OF VESSELS AND

See also dust explosion incidents, geometry of vessels and pipework,... 

See also GEOMETRY OF VESSELS AND PIPEWORK, DEFLAGRATION TO DETONATION Methane... 

Note it is assumed that the geometry of vessel is not changed and that it does not fail due to fire impact. 

Effect of Vessel and Impeller Geometry and Scale. The effects of the geometry of the impeller, vessel, and its internals are subsumed in the... 

Skirts are used in vessels and towers. They transmit high axial and bending loads and offer favorable geometry for thermal gradients. In piping, when loads are beyond the capacity of lugs and tmnnions, skirts are often favored. 

Variables It is possible to identify a large number of variables that influence the design and performance of a chemical reactor with heat transfer, from the vessel size and type catalyst distribution among the beds catalyst type, size, and porosity to the geometry of the heat-transfer surface, such as tube diameter, length, pitch, and so on. Experience has shown, however, that the reactor temperature, and often also the pressure, are the primary variables feed compositions and velocities are of secondary importance and the geometric characteristics of the catalyst and heat-exchange provisions are tertiary factors. Tertiary factors are usually set by standard plant practice. Many of the major optimization studies cited by Westerterp et al. (1984), for instance, are devoted to reactor temperature as a means of optimization. 

Usually, the geometry is determined by space limitations. Both horizontal or vertical cyhndrical vessels are designed as pressure vessels, and for pressures up to 50 psig, an L/D ratio of 2 to 3 results in an economic design. 

Standard Geometry describes a vessel and mixer design based on a fluid depth equal to vessel diameter and a top-entering impeller having a diameter equal to 1/3 of vessel diameter and located with a clearance of 1/3 of vessel diameter above the bottom of the vessel. 

The two types of vessel geometries employed are vertieal and horizontal. In most of the fine ehemieals proeesses the leaves are fitted into vertieal vessels whereas horizontal vessels are used in the heavier process industries sueh as the preparation of sulfur in phosphoric acid plants. The leaves inside horizontal tanks may be positioned either along the tank axis or perpendieular to the axis. In order to utilize the tank volume for maximum filtration area the width of the leaves is graduated so they fit to the eireular eontour of the tank. 

The principal unresolved uncertainties in MARCH involve core melting and containment behavior. Important details that are not well known are (1) the core liquefaction temperature (the core acts like a two-phase slurry), (2) the maximum temperature, (3) changes in the zircalloy oxidation rate because of geometry changes and reaction with UOj, and (4) the amount of corium and steel that is expelled from the vessel and the rate of expulsion. 

Even if satisfactory equations of state and constitutive equations can be developed for complex fluids, large-scale computation will still be required to predict flow fields and stress distributions in complex fluids in vessels with complicated geometries. A major obstacle is that even simple equations of state that have been proposed for fluids do not always converge to a solution. It is not known whether this difficulty stems from the oversimplified nature of the equatiorrs, from problems with ntrmerical mathematics, or from the absence of a lamirrar steady-state solution to the eqrratiorrs. 

The earth itself is the reaction vessel and chemical plant. The complicated reaction chemistry and thermodynantics involve ntixers, reactors, heat exchangers, separators, and flnid flow pathways that are a scrambled design by nature. Only the sketchiest of flowsheets can be drawn. The chemical reactor has complex and ill-defined geometry and must be operated in intrinsically transient modes by remote control. Overcoming these difficulties is a trae frontier for chemical engineering research. 

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