Exchange factors, Covers

Here the absorptivity depends on the spacing of the tubes and is given by item 5 of Table 8.16. The cold plane area Acp is the product of the number of tubes by their lengths and by the center-to-center spacing. The combination (xAcp is equal to the area of an ideal black plane that has the same absorptivity as the tube bank, and is called the equivalent cold plane area. Evaluation of the exchange factor F is explained in item 9 of Table 8.16. It depends on the emissivity of the gas and the ratio of refractory area A to the equivalent cold plane area aAcp. In turn, A = A — Acp, where + is the area of the inside walls, roof, and floor that are covered by refractory. 

For an exchanger AAith alloy parts and a design pressure of 150 Ibf/im, the alloy extras are added. For shell and shell cover the combined alloy-pressure extra is the alloy extra times the shell-side pressure extra/100. For channel and floating-head cover the combined alloy-pressure extra is the alloy extra times the tube-side pressure extra/100. For tube sheets and baffles the combined alloy-pressure extra is the alloy extra times the higher-pressure extra times 0.9/100. (The 0.9 factor is included since baffle thickness does not increase because of pressure.)... 

Adsorption to the K+-covered siloxane surfaces of the clay, illite, can be estimated using Eq. 11-20. A tnt.eda is 300,000 L mol-1 and the surface area factor, /saf, for illite is 6 (Table 11.2). Since the ground water contains so much calcium relative to potassium (30 1), only a very small fraction of the cation exchange sites on the illite are covered with weakly hydrated potassium ions you assume/K+clay is about 0.01. Thus, you estimate ... 

Currently, anthropogenic S02 production exceeds natural SO2 production by a factor of 3 (Bates et al. 1992), but the impact of the former on aerosol production is largely confined to industrialised areas of the Northern Hemisphere. The oceans, on the other hand, cover approximately 70% of the Earth s surface and much of this area is remote from man-made atmospheric contaminants. Consequently, the exchange of marine DMS is of high regional importance and may affect climate globally. Since the publication of a global inventory of DMS data by... 

In the literature, one can hnd theoretical and practical studies relating to heat transfer conditions in scraped-surface heat exchangers (19, 54), which cover factors such as specific weight, specific heat, latent heat of crystallization, dry matter content, retention time, and overall heat transfer conditions. 

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