Process for fractional separation of a plurality of components from the mixture thereof

A process for fractional separation of a plurality of components from the mixture thereof in a system comprising a group of a number of packed bed units packed with an adsorbent and connected with each other to form an endless, or continuous, series of a circulatory fluid channel in which system a state that a fluid is flowed into said channel or to the outside of said channel while continuously circulating the internal fluid, can be changed either into or from a state that the fluid is flowed into said channel or to the outside of said channel while substantially shutting off the internal fluid circulation at at least one position of the channel, or system, and in which system a fluid feed having three or more components having respective mutually different affinities for said adsorbent is flowed through said group of packed bed units to separately form an adsorption zone enriched with a component having a weak affinity for said adsorbent, an adsorption zone enriched with a component having a strong affinity for said adsorbent and at least one adsorption zone enriched with a component having an intermediate affinity for said adsorbent:

• which process comprises repeating a cycle comprising
• a step (1) of substantially shutting off the internal fluid circulation at at least a position of said system immediately upstream of the packed bed unit where the components having the weak and intermediate or strong affinity for the adsorbent coexist,
• and sequentially withdrawing, from the same position in the system, a fraction enriched with said component having the intermediate affinity for said adsorbent and a fraction enriched with said component having the strong affinity for said adsorbent while feeding the fluid feed from top, or upstream side, of the packed bed unit, immediately downstream of the shut-off position or the second packed bed unit downstream thereof;
• and
• a step (2) of withdrawing the fraction enriched with said component having the weak affinity for said adsorbent and remaining in the system after the step (1) above and sequentially shifting, in step with the migration of the adsorption zones downstream of the system, the position of feeding a fluid desorbent into the system and the position of withdrawing the fraction enriched with said component having the weak affinity for said adsorbent while circulatorily flowing the internal fluid without feeding the fluid feed but simultaneously feeding the fluid desorbent into the system.

A process for fractional separation of a plurality of components from the mixture thereof in a system comprising a group of a number of packed bed units packed with an adsorbent and connected with each other to form an endless, or continuous, series of a circulatory fluid channel in which system a state that a fluid is flowed into said channel or to the outside of said channel while continuously circulating the internal fluid, can be changed either into or from a state that said fluid is flowed into said channel or to the outside of said channel while substantially shutting off the internal fluid circulation at at least one position of the channel, or system, and in which system a fluid feed having three or more components having respective mutually different affinities for said adsorbent is flowed through said group of packed bed units to separately form an adsorption zone enriched with a component having a weak affinity for said adsorbent, an adsorption zone enriched with a component having a strong affinity for said adsorbent and at least one adsorption zone enriched with a component having an intermediate affinity for said adsorbent:

• which process comprises repeating a cycle comprising
• a step (1) of substantially shutting off the internal fluid circulation at at least a position of said system immediately upstream of the packed bed unit where the components having the weak and intermediate or strong affinity for the adsorbent coexist, and withdrawing a fraction enriched with said component having the intermediate affinity for said adsorbent from the end of the packed bed unit containing said fraction mentioned just above, while feeding the fluid feed from top, or upstream side, of the packed bed unit immediately downstream of the shut-off position or the second packed bed unit downstream thereof;
• a step (2) of withdrawing said fraction enriched with said component having the weak affinity for said adsorbent from the end of the packed bed unit containing said fraction mentioned just above and sequentially shifting, in step with the migration of the adsorption zones downstream of said system, the position of feeding the fluid desorbent into the system and the position of withdrawing the fraction enriched with the component having the weak affinity for said adsorbent, while circulatorily flowing the internal fluid without feeding the fluid feed but simultaneously feeding a fluid desorbent into the system;
• and
• a step (3) of withdrawing the fraction enriched with the component having the weak affinity for said adsorbent from the end of the packed bed unit containing said fraction enriched with said component having the weak affinity for said adsorbent, and at the same time withdrawing the fraction enriched with said component having the strong affinity for said adsorbent from the end of the packed bed unit containing said fraction mentioned just above, and, if desired, withdrawing said at least one fraction enriched with the component having the intermediate affinity for the adsorbent from the end of the packed bed unit containing said fraction enriched with said component having the intermediate affinity for said adsorbent, while at the same time circulating the internal fluid and feeding the fluid desorbent into the system and sequentially shifting, in step with the migration of the adsorption zones, the position of feeding said fluid desorbent and the positions of withdrawing the respective fractions.