Regenerable adsorbent

Adsorption and Desorption Adsorbents may be used to recover solutes from supercritical fluid extracts for example, activated carbon and polymeric sorbents may be used to recover caffeine from CO9. This approach may be used to improve the selectivity of a supercritical fluid extraction process. SCF extraction may be used to regenerate adsorbents such as activated carbon and to remove contaminants from soil. In many cases the chemisorption is sufficiently strong that regeneration with CO9 is limited, even if the pure solute is quite soluble in CO9. In some cases a cosolvent can be added to the SCF to displace the sorbate from the sorbent. Another approach is to use water at elevated or even supercritical temperatures to facilitate desorption. Many of the principles for desorption are also relevant to extraction of substances from other substrates such as natural products and polymers. 

Catalyst and adsorbent could be easily manufactured 2. The proprietary composition is difficult to imitate. 1. Catalyst is relatively new technology for indoor air cleaners 2. Regenerable adsorbent is new for the industry. 

Supercritical fluid extraction can be used to remove carbonaceous material from spent catalysts. De Filippi and Robey (2) used supercritical carbon dioxide extraction to regenerate adsorbents. Abel (3) tried supercritical carbon dioxide extraction to regenerate a certain catalyst. Tiltscher et al. (4,5) studied the isomerization of 1-hexene on an alumina catalyst and showed that under supercritical conditions, 1-hexene was able to remove the oligomeric compounds (C -C q) from t ie catalyst surface and prevent coking. 

The adsorption columns were of 27 mm in i.d. and 300 mm in length. A certain amount of regenerated adsorbent was packed into each column, as shown in Table. 2. Temperature was set to 303.13 K by use of a constant temperature bath. A thermocouple was inserted into the column at 13 cm from the bottom. The concentration changes in product gas were measured until a cyclic steady state was obtained. Concentration of feed, product and exhaust gases were determined by a gas chromatograph (SHIMAZU GC-7A) equipped with a thermal conductivity detector. 

There are numerous commercial processes available to remove the sulfur content from syngas, ranging from throwaway regenerable adsorbent-type to regen-erable solvent-type processes. Solvent-type processes are of primary interest for sulfur removal from syngas. The solvent-type processes can be divided into three types ... 

Three generic adsorptive process schemes have been commercialized to serve most of the applications shown in Table 1. They include 1) temperature swing adsorption (TSA) 2) pressure swing adsorption (PSA) and 3) concentration swing adsorption (CSA).P The fluid mixture (feed) to be separated is passed over a regenerated adsorbent (contained in an adsorber vessel) to produce a stream enriched in the less strongly adsorbed components of the mixture. 

U.S. 4,124,528 Process for regenerating adsorbents with supercritical fluids, Nov. 7, 1978. 

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