Adsorption chamber

Most adsorption systems use stationary-bed adsorbers. However, efforts have been made over the years to develop moving-bed adsorption processes in which the adsorbent is moved from an adsorption chamber to another chamber for regeneration, with countercurrent contacting of gases with the adsorbents in each chamber. Union Oil s Hypersorption Process (90) is an example. However, this process proved uneconomical, primarily because of excessive losses resulting from adsorbent attrition. 

A simplest vessel used for experimental investigation of pyrolysis of hydrogen, oxygen, and nitrogen, as well as other molecules is shown in Fig.4.3. The pyrolysis Hlament (below) is separated from the adsorption chamber (above) by a plane shutter driven by a magnet, whidi permits the sensor to be exposed to the established atomic flux during a required... 

The faujasite zeolite in the UOP Parex process has some finite affinity for aU the aromatic species in the mixed xylene feed, indicated by the fact that selectivities between the components are typically less than five. Because the adsorbent has the tendency to adsorb all aromatic species in the feed to some extent, the fundamental variable dictating the adsorption zone operation is the ratio of zeolitic selective pore volume circulated past the feedpoint by the stepping action of the rotary valve per the volume of aromatics conveyed to the adsorption chambers. Typically this ratio is set to obtain a certain target recovery of p-xylene. 

The Molex process developed by U.O.P. is unique not only in its liquid-phase operation but also in its adsorption system (1-8). Its adsorption system consists of a single adsorption tower with multiple inlet-outlet points and a special rotary valve. The adsorption tower has many smaller adsorption chambers interconnected in series, and it operates under the so-called simulated moving bed operation. Instead of moving the adsorbent bed, the simulated moving bed operates by simultaneously advancing inlet-outlet points periodically. At any time, the adsorber has four zones—viz., adsorption, primary rectification, desorption, and secondary rectification zones, and these zones advance simultaneously as the rotary valve turns periodically. Desorption of n-paraffins is achieved by displacement. 

Figure 1. Schematic of apparatus A, calibrated variable-volume mercury burette B, reference volume C, main chamber D, mixing pump E, adsorption chamber F, reference chamber G, constant temperature baths H, mercury manometer J, cold-cathode gauge P, Pirani vacuum gauge R, mercury reservoir...

Adsorption isotherms were determined on a Cahn 1000 vacuum micro-balance system, using a Leybold-Heraeus Turbotronic TMP 120 turbomolecular pump for evacuation and a variable-leak valve for adsorbate gas injection. Approximately 0.3 grams of the sodium-exchanged zeolite was placed into a 1 cm. diameter hemispherical quartz sample pan within the adsorption chamber... 

Description The separation takes place in an adsorption chamber (2) that is divided into a number of beds. Each bed contains proprietary shape-selective adsorbent. Also, each bed in the chamber is connected to a rotary valve (1). The rotary valve is used along with the shape-selective adsorbent to simulate a counter-current moving bed adsorptive separation. Four streams are distributed by the rotary valve to and from the adsorbent chamber. The streams are as follows ... 

The adsorption data of the n-alkanes were measured according to standard procedures the adsorption chamber was pressurized with the pure gas at approximately the desired pressure and then sealed. Then, the pressure and the change in the mass (weight) of the... 

The adsorbents are activated in vacuo below 10" torr at 350°—400°C for 16 hours. Desorptions are carried out by repeatedly connecting the adsorption chamber to an evacuated vessel from which the desorbate is collected in a mixing chamber. Desorptions usually are carried out at the adsorption temperature, and completeness of removal is checked by material balance it is usually within 2%. Occasionally, to speed up the procedure, desorptions may be carried out at elevated temperatures. 

Essentially all Sorbex process units consist of an adsorption chamber, a Rotary Valve and an extract and a Raffinate Column. Process flow scheme is as shown in Fig. 3.6 [11,12]. 

The main analyser chamber contains a spectrometer and ports for different excitation sources. The preparation chamber is needed for sample preparation e.g. cleavage). The electrolyte components are allowed to react with the interface in the adsorption chamber, where temperature control is used to stabilise the interface-adsorbate interaction. Water, halogen and alkali species are allowed to interact with electrode material to investigate structure and potential distribution of the electrochemical double layer (Sass, 1983 Bange et al, 1987 Sass et al., 1990). laegermann (1996) gives a comprehensive review of the semicondnctor/electrolyte interface within the vacnnm science approach. 

For each experiment, a new mica window was prepared from a thin sheet (5 to 7 microns) of cleaved Indian ruby mica. The window was moimted in the adsorption chamber and thoroughly washed with twice-distilled benzene. 

The Figure 2 is the principle diagram of the experiment system which will discover the sorting characteristic of gas and coal outburst. This experiment system mainly includes gas cylinder and gas adsorption chamber, outburst hole and rubber membrane, pressure sensor speed sensor and high-speed camera, small coal sorting acquisition boards and so on. 

I. Gas cylinder 2. Gas adsorption chamber 3. Outburst hole and rubber membrane 4. Pressure sensor 5. Speed sensor 6. Model of roadway 7. High-speed camera. 8. Personal computer 9. Small coal "sotting" acquisition board... 

Apparent Density - This is the bulk density of the adsorbent shapes. It is simply the total weight of adsorbent shapes held within a volume, measured in g/cc or more likely, Ib/CF. This measurement indicates the weight quantity of adsorbent shapes necessary to fill the adsorption chamber. This value should be at least 0.44 g/cc (27.5 Ib/CF) and perhaps as much as 0.58 g/cc (36.2 Ib/CF) - depending upon the chosen size of the particle shape, and the methods of carbonization and activation . ... 

An instrument for volumetric measurements of pure gas adsorption basically consists of a gas storage vessel (volume Vsv) and an adsorption chamber (Vac) being connected by a tube bearing a valve. Both vessels should completely be placed within a thermostat (water, oil, air etc.) and provided with tubes for gas supply and evacuation as well as with thermometers and manometers to measure the temperature (T) and pressure (p) inside the vessels, cp. Figure 2.1. 

To measure adsorption a certain amount of gas of mass (m ) is prepared in the storage vessel and the adsorption chamber is evacuated. Upon opening the expansion valve, the gas expands to the adsorption chamber where it is partly adsorbed on the (external and internal) surface of the sorbent material. This process may last milliseconds, minutes, hours or even several days - as in case of helium on activated carbon (Norit Rl) [2.8]. After thermod)mainic equilibrium, i. e. constancy of pressure (p) and temperature (T) inside the vessels has been realized, these data can be taken as a basis to calculate the mass of the gas adsorbed on the sorbent (m ). That is, volumetric adsorption experiments mainly result in pressure measurements. Hence the name Manometry for this method should be used [2.2]. 

The quantity m in Eq. (2.1) on principle also includes the mass of gas adsorbed on the walls of the adsorption chamber and possibly desorbed from the walls of the storage vessel upon gas expansion (Am jii). These quantities should be determined by calibration... 

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