Region side-stream

As it has been shown, in AR approach the construction of the boundary is essential. Feinberg and Hidebrandt (1997) demonstrated that the boundary of attainable region could be assembled only by means of combinations of PFRs, CSTRs, and DSRs (differential side-stream reactors). The calculation of these elementary reactors is simple. The construction of an AR is not complicated, if the analysis is restricted at two dimensions. Moreover, 3-D representation could be visualised relatively easy with an appropriate computer tool. In the case of systems of higher dimensions the method relies rather on numerical techniques, and is not easy to apply. 

The target of most commercial SSCs has focused mainly on the separation of zeotropic mixtures. The criteria for the use of side streams for the separation of ideal mixtures with the expected feed composition regions of SSC arrangements are (Tedder and Rudd, 1978) ... 

Solving for 3/5+ the operating line for the region between the side stream and the feed is... 

Other factors that affect either production cost or the consumption of fertilisers tend to be periodic and short-Hved. On the consumption side, weather conditions, prices of fertilisers, and the pohtical stabiUty of a region influence demand. The supply side is influenced by raw material availabihty, rehabihty of infrastmcture, on-stream efficiency, age of plants, and the constmction or modernisation of existing plants. 

The reduction of the sample was made at 2250 K In a flowing stream of hydrogen carrier gas ( SO cm /mln). The total pressure of the carrier gas was approximately 1 atm. The water vapor produced during the reduction was swept by the carrier gas Into an electrolytic-type (P2O5) moisture monitor and a continuous recorder trace of the water concentration as a function of time was obtained. A typical plot of the moisture content of the carrier gas as a function of time Is shown In Figure 3. The region on the left side of this figure where the moisture content... 

As can be expected, the intensive fluctuation region is symmetrical with respect to the impingement plane, provided the two streams leaving the drawing tubes are at the same velocity. This is simply because the two sides of the reactor have the same structure. In addition, the figures also show that the region is essentially symmetrical about the flow axis, suggesting that the above assumption is reasonable. 

Optimization of the coiled-tube heat exchanger is quite complex. There are numerous variables, such as tube and shell flow velocities, tube diameter, tube pitch, and layer spacing. Other considerations include single-phase and two-phase flow, condensation on either the tube or shell side, and boiling or evaporation on either the tube or shell side. Additional complications come into play when multicomponent streams are present, as in natural gas liquefaction, since mass transfer accompanies the heat transfer in the two-phase region. 

While the engineer may frequently be interested in the heat-transfer characteristics of flow systems inside tubes or over flat plates, equal importance must be placed on the heat transfer which may be achieved by a cylinder in cross flow, as shown in Fig. 6-7. As would be expected, the boundary-layer development on the cylinder determines the heat-transfer characteristics. As long as the boundary layer remains laminar and well behaved, it is possible to compute the heat transfer by a method similar to the boundary-layer analysis of Chap. 5. It is necessary, however, to include the pressure gradient in the analysis because this influences the boundary-layer velocity profile to an appreciable extent. In fact, it is this pressure gradient which causes a separated-flow region to develop on the back side of the cylinder when the free-stream velocity is sufficiently large. 

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