Sorption systems

Rockenfellcr, U. et al. Advanced heat pump staging for complex compound chemi-sorption systems. In proceedings of Solid Sorption Refrigeration, Paris, HR, 1992, pp,153 159. 

A closed sorption system is shown in Figure 8. It is based on the same physical effect as the open storage. However the engineering is quiet different from open sorption systems. Closed system could be more precisely described as evacuated or air-free systems. The operation pressure of the fluid to be sorbed can be adjusted in theses systems. In closed systems components, which are not existing in the atmosphere, can be used, because there is no connection to the ambience. 

Figure 234 is showing a closed sorption system using water vapor as adsorptive. The heat has to be transferred to and from the adsorbent by an heat exchanger. This holds also for the condenser/evaporator. Heat has to be transported to the adsorber and at the same time the heat of condensation has to be distracted from the condenser in order to keep up the water vapor flow... 

The temperature lift is defined as AT = Tair out — Tair in. The possible AT is crucial for the design of sorption systems for heating applications. The temperature lift of each adsorbent can be very different under the same adsorption conditions. The temperature lift can be calculated as... 

The self cooling beer keg is based on the principle of closed sorption systems shown in chapter Y2 Figure 8. Figure 244 shows the beer keg from the outside and the inside. 

Looking at the beer keg sorption system as an indirect heat storage, the system would look like Figure 246. The first part of Figure 3 shows the charging... 

The application of open sorption systems can provide dehumidification by the adsorption of water vapor and sensible cooling by adiabatic humidification (after a cold recovery for the dried air) at temperatures between 16 °C and 18 °C. Conventional systems have to reach temperature as low as 6 °C or lower in order to start dehumidification by condensation. For comfort reasons this cold air has to be heated up to about 18 °C before released into the building. This shows that open sorption systems can provide in general an energetically preferable solution. 

Brown, C.J. (1999) Mixed acid recovery with the APU acid sorption system - an update. Paper presented at the Cleaner Production Workshop, China Steel Corporation, Kaohsiung, Taiwan. 

U.S. Filter s powdered activated carbon treatment (PACT ) is a sorption system used to treat water contaminated with organics, inorganics, dyes, and metals. PACT combines biological treatment and powdered activated carbon (PAC) adsorption in one unit to attain treatment standards not readily attainable with these treatments independently. 

The coals were acetylated in the apparatus shown in Figure 2. The reaction chamber was 40 mm. in diameter and about 15 cm. long. This apparatus was connected to the same vacuum line as the sorption system. A steel rack, shaped to fit within the reaction chamber and provided with a taut nichrome wire to hold the sample buckets, is shown in Figure 3. 

About one-half of the radioiodine in the targets remains in the caustic-nitrate solution which is stabilized with sodium thiosulfate and stored until the radioiodine decays. During the acid dissolutions, the dissolver off-gas is directed to the iodine sorption system in which the gas is contacted with a 10 hi HNO3—0.4 M Hg(N03)2 solution in an absorption column. Then, the... 

Another significant effect is connected to the bulk concentration of the external solution (Cq). It is shown (Sec. IV) that the bulk concentration effects not only the concentration (Cg) of the invading counterion in the bead but, more importantly, the selectivity of exchanger for the exchanging counterions. According to the theory of mass transfer in sorption systems [63] the motion of the sorption concentration front of substances depend on the curvature of their sorption isotherm. For IE selective systems this effect is connected to the selectivity factor since this factor controls the shape of the ion-exchange isotherm. 

Figure 1. Experimental Set-up of high-temperature metal vapor sorption system I. Flow meter 2. Needle valve 3. Nj 4. O2 5. Steam generator 6. Gas mixer 7. Valve 8. Thermo gravimetric furnace 9. High temperature sorption bed 10. Thermocouple II. Filter 12. Impingers 13. Furnace controller 14. Silicagelbed IS. Vacuum pump 16. Dry gas-meter...

Figure 3. Domain-complexion diagrams (at left) and phase distribution (at right, condensate in black, vapour in blank) within the pores (sites circles, bonds cylinders) on planes of 3D porous networks for actual states of diverse sorption processes, a) Boundary ascending (BA) curve on network la, b) boundary descending (BD) curve on network 2a, c) primary ascending (PA) curve on network 3a and d) primary descending (PD) curve on network 4a. Rc is the critical radius of curvature at the present state of the sorption process and Rc is the critical radius of curvature at the point of reversal for scanning curves. Shaded areas (pores filled with condensate) delimited by full lines in the complexion diagrams represent current states of the sorption systems, broken lines delimit states at the points of reversal.

An example of the use of ab initio XANES calculations to determine nanoparticle structure is the Zn/ferrihydrite sorption system examined by Waychunas et al. (2001). In the case of sorption complexes the XAI S spectrum of the sorbed species will contain information about the local structure of the substrate, and thus the structural nature of the full sorption complex. In the Zn/ferrihydrite system it was observed via EXAFS that the number of Fe next nearest neighbors about the sorbed Zn ion decreased as the Zn sorption density increased. Direct calculation of the XANES structure identified MS paths that changed in number as a function of cluster size (and thus number of neighbor Fe atoms), and gave rise to XANES features that changed in intensity (Fig. 32). These changes agreed well with the structural interpretation of the EXAFS and the crystal chemistry of Zn-Fe hydroxides. 

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