Condensers design layout

The vertical cylindrical column provides, in a compact form and with the minimum of ground requirements, a large number of separate stages of vaporisation and condensation. In this chapter the basic problems of design are considered and it may be seen that not only the physical and chemical properties, but also the fluid dynamics inside the unit, determine the number of stages required and the overall layout of the unit. 

The magnitude of the individual coefficients will depend on the nature of the heat transfer process (conduction, convection, condensation, boiling, or radiation), on the physical properties of the fluids, on the fluid flow rates, and on the physical arrangement of the heat transfer surface. As the physical layout of the exchanger cannot be determined until the area is known, the design of an exchanger is of necessity a trial-and-error procedure. The steps in a typical design procedure are as follows ... 

The two basic chamber/condenser layouts (that is, internal or external condenser) are illustrated in Figure 10.2. While there has been controversy over the most suitable layout, Rowe has suggested that neither design has an overall advantage in terms of safe operation. 

Polymers with intrinsic microporosity, abbreviated as PIMs, were developed for the first time by McKeown and Budd. The general design strategy involves incorporation of extended aromatic components within a rigid polymer network in order to imitate the structural layout of graphene sheets of activated carbons.The principle behind the synthesis of PIMs employs non-reversible condensation reactions to form polymers. These polymers cannot efficiently fill the space and pack together due to components that are rigid and ladder-like, and thus force the backbone of the polymer to twist or turn. 

Exhibit 4-27 illustrates how primary process considerations govern the elevation of the surface condenser and some of its auxiliary equipment. Because a pump is needed to remove the condensate from the hot well, the pump net positive suction head (NPSH) must be satisfied to operate satisfactorily. Vertical pumps are generally used in this application because the NPSH requirement is calculated from the bottom of the lower impeller for vertical pumps, compared with the centerline of the inlet nozzle for horizontal pumps. Setting the elevation of the inter-after condenser, usually located to the side of the suifice condenser, can be done with fewer restriaions. Ilie bottom of the inter-after condenser shell must not be more than 3 ft (900 mm) below the condensate return nozzle on the side of the hot well. The plant layout designer is then free to set the elevation as high as necessary. 

Figure 1.16 Schematic layout of hypothetical process for semi-continuous extraction from bed of particulate solids using a supercritical solvent. The layout shown above for the product recovery and recompression units is not necessarily the most economic one and the design engineer would wish to examine other possibilities. The ideal work requirement, for example, which from Figure 1.19 is 30 joules per gram of CO2 recirculated, could be substantially reduced by condensing the CO2 and recompressing in the liquid state (see chapter 9). However, the subsequent return of the CO2 stream to the extraction temperature would involve an appreciable heat load. It might also be preferable to operate the separator under sub-critical conditions. The economic consequences of these and other modifications would need to be examined in the light of the requirements of the particular process and the availability of services on the plant site.

The shielding and containment for a modern BWR typically comprises a steel or concrete inner containment (the drywell) connected by underwater ducts to a suppression pool full of water, the purpose of which is to condense the escaping steam in the event of a circuit breach. Two layouts which have been adopted are the bulb-and-torus design (Fig. 9.2) and the more recent weir wall construction described in detail later for the Grand Gulf BWR. The standard PWR containment consists of a concrete structure with either a... 

It should be possible to develop ring design heuristics that can generate clear and aesthetic layouts for even highly condensed ring systems such as cubane. Although there is no substitute for an RTD to lay out and orient traditional systems (steroids), the RTD approach alone is inadequate because the presence of substituents can affect the optimal layout. 

A layout for the Super LWR NPP is drawn in Fig. 3.2 [2]. It is a two-loop system. The supercritical steam flows into the turbine system through the outlet nozzles of the RPV and the main steam lines. The water is pumped out of the condenser by a series of pumps and back to the reactor through the inlet nozzles. A series of low pressure and high pressure feedwater heaters are placed upstream and downstream from the main feedwater pumps, respectively, to preheat the cold water before it flows into the reactor. The safety system design and characteristics are discussed in Chap. 6 in detail. 

---