Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Regeneration sequence control

With some exceptions mentioned later, the first stage in the regeneration sequence of operations is backwashing with a controlled upflow of water to give typically 30-40% bed expansion. Backwashing a bed, where applicable, serves to effect the following important requirements ... [Pg.168]

Filtration involves the flow of a fluid through a porous medium. Solid particles present in the fluid entering the filter deposit onto that medium. The typical filter in a brine or caustic plant relies either on a bed of solids or on a porous cloth or cartridge for the separation. The operation becomes semi-continuous, with the filter operating until the amount of solid deposited from the fluid has sufficient effect to make its removal necessary. These filtrations, therefore, require multiple units to allow the operation to continue during the regeneration of one filter and sequence controllers to take the operation through the various steps without constant attention from the operators. [Pg.1057]

Adsorption-Control Equipment If a gas stream must be treated for a short period, nsnally only one adsorption unit is necessary, provided, of course, that a sufficient time interval is available between adsorption cycles to permit regeneration. However, this is usually not the case. Since an nninternipted flow of treated gas is often required, it is necessary to employ one or more units capable of operating in this fashion. The units are designed to handle gas flows without interruption and are charac terized by their mode of contact, either staged or continuous. By far the most common type of adsorption system used to remove an objectionable pollutant from a gas stream consists of a number of fixed-bed units operating in such a sequence that the gas flow remains nninternipted. A two- or three-bed system is nsn ly... [Pg.2187]

Figure 4 shows a sequence of cyclic voltammograms recorded in a CO saturated solution of 0.5 M H.SO, which contained 10-5 M SnCl,. These voltammograms were recorded by increasing the upper limit of the potential during successive cycles. The major feature is the CO oxidation peak at 0.6 V(SCE) that is observed in the later scans. For cycles with an upper limit below this potential, there is a second, smaller oxidation feature at about 0.4 V. Control experiments using an SnCl /H.SO solution without CO show that this feature can be assigned to the oxidation of adsorbed Sn atoms. We note that the Sn oxidation step does not produce a well-resolved current maximum in the curves in Figure 4. We interpret this to indicate that adsorbed CO molecules are rapidly oxidized by newly generated Sn cations, thus regenerating the Sn adatoms and allowing further oxidation current to flow. Figure 4 shows a sequence of cyclic voltammograms recorded in a CO saturated solution of 0.5 M H.SO, which contained 10-5 M SnCl,. These voltammograms were recorded by increasing the upper limit of the potential during successive cycles. The major feature is the CO oxidation peak at 0.6 V(SCE) that is observed in the later scans. For cycles with an upper limit below this potential, there is a second, smaller oxidation feature at about 0.4 V. Control experiments using an SnCl /H.SO solution without CO show that this feature can be assigned to the oxidation of adsorbed Sn atoms. We note that the Sn oxidation step does not produce a well-resolved current maximum in the curves in Figure 4. We interpret this to indicate that adsorbed CO molecules are rapidly oxidized by newly generated Sn cations, thus regenerating the Sn adatoms and allowing further oxidation current to flow.
The phosphatidylinositol pathway is completed by regeneration of the phospholipid from IP3 and DG. It is remarkable that IP3 is successively dephosphorylated to mositol. The last step of this sequence is inhibited by Li ions, which block phosphatidylinositol synthesis. Li salts are used to control the symptoms of manic-depressive illness, an affective mental disorder (see section 3.5.4), and it is thus tempting to implicate the last reaction of the PI pathway in the etiology of this disorder. [Pg.96]

After further heat recovery, final cooling and condensate separation (6), the gas is sent to the pressure swing adsorption (PSA) unit (7). Loaded adsorbers are regenerated isothermally using a controlled sequence of depressurization and purging steps. [Pg.14]

The configuration of most ion exchange plants involve one or several fixed resin beds contained in cylindrical pressure vessels interconnected by pipework. Valves control and direct pumped or gravity fed liquid flows in a strictly controlled sequence, and safely designed regenerant measuring plus dilution systems are required to handle resin regeneration chemicals. Finally, instrumentation is required to monitor liquid levels, flows, pressures, volumes, and product quality. [Pg.261]


See other pages where Regeneration sequence control is mentioned: [Pg.268]    [Pg.268]    [Pg.12]    [Pg.116]    [Pg.253]    [Pg.283]    [Pg.315]    [Pg.170]    [Pg.90]    [Pg.94]    [Pg.378]    [Pg.63]    [Pg.208]    [Pg.253]    [Pg.150]    [Pg.82]    [Pg.255]    [Pg.77]    [Pg.283]    [Pg.19]    [Pg.16]    [Pg.640]    [Pg.817]    [Pg.1043]    [Pg.510]    [Pg.956]    [Pg.277]    [Pg.513]    [Pg.240]    [Pg.1180]    [Pg.337]    [Pg.217]    [Pg.34]    [Pg.817]    [Pg.1043]    [Pg.683]    [Pg.209]    [Pg.537]    [Pg.168]    [Pg.386]    [Pg.601]   
See also in sourсe #XX -- [ Pg.268 ]




SEARCH



Regenerator control

Sequence control

© 2024 chempedia.info