Regeneration periodic

Regenerated periodically to remove unwanted eluant ions)... 

Design a plant to make 20,000 tonnes per annum of refined aniline by the hydrogenation of nitro-benzene. The total of on-stream operation time plus regeneration periods will be 7500 hours per year. 

These results suggest that oxidation state is not solely responsible for catalyst deactivation but that other factors such as V location and mobility may play an important role. Basic alkaline earth oxide passivators such as MgO, admixed to the catalyst, interact strongly with vanadium during the regeneration period. Although the oxidation state of vanadium is essentially unaffected, MgO structurally modifies V as evidenced by a unique X-ray absorption spectrum. 

The next development was the use of internal cooling by intermittent water circulation during the regeneration period. The heat was removed by radiation and flue gas convection from the walls of perforated pipes to water-cooled tubular coils installed inside these pipes. Thus, direct contact with the catalyst was avoided, which precluded cooling parts of the catalyst to temperatures at which combustion would stop. Most of the heat of combustion was recovered as steam. This was the basis of the design of the first commercial unit installed and operated in 1936. 

The catalyst must be regenerated periodically throughout the operation. The fresh catalyst has an activity such that k = 0.30 s-1. 

Ease of catalyst circulation through separate zones for continuous regeneration, periodic operation or other applications... 

A catalytic process uses a catalyst which must be regenerated periodically because of... 

In the second type of cycle, the regeneration period is twice as long as the on-stream period. Four catalyst cases are involved one on stream, two being regenerated, and the other undergoing purge or valve changes. This type of cycle is adaptable to on-stream periods as short as 7)- ... 

Starch was oxidized by Jackson and Hudson,who used periodic acid at room temperature. Considerable study has recently been made of the oxidation of starch on a commercial basis, using electrolytically regenerated periodic acid. The reaction is carried out under what are normally drastic conditions for a periodate oxidation, namely pH 1.2-1.4 and 100°F, apparently without occurrence of any over-oxidation. Oxystarch is known commercially as dialdehyde starch. ... 

Carrier gases are usually hydrogen, helium or nitrogen which are dried by passing through a molecular sieve column. This is regenerated periodically with a positive flow of gas and heating to 200 °C. 

Ion-exchange resins behave like storage batteries, as they must be recharged (regenerated) periodically to restore their exchange capacity. A cation resin is regenerated with... 

In the earlier instruments, the suppressor unit was a cation-exchange column of high capacity that had to be regenerated periodically. Newer suppressors contain ion-exchange membranes that can be regenerated continuously by flowing a solution of sulfuric acid over the outer membrane surface or by electrically generated acid. 

---