Adsorption beds and method of operation thereof
AssigneeNear Equilibrium Research Associates
InventorMichael D. Oliker
Life of this patent
Estimating the term…
Abstract
Disclosed is a method of operating adsorption beds of the type which are regenerable with heat and a bed which exploits the method. By altering the timing of the beginning and termination of the adsorption stage, the regeneration stage, and the cooling stage, it is possible to significantly reduce energy consumption, increase the throughput of the bed, provide greater security against breakthrough, produce a more adsorbate-free product, or attain certain combinations of these advantages.
Claims24
A method of operating an adsorption bed having an adsorbent material disposed within a housing defining a feed entrance, a fluid flow path, and a product exit, said adsorbent material being of the type used to reduce the concentration of an adsorbate carried by a fluid feed, said method including cycling the bed through an adsorption stage wherein the fluid feed is passed through the bed and a fluid product of reduced adsorbent concentration is collected at the product exit, and a thermal regeneration stage wherein a hot regenerant fluid and a cooling fluid are serially passed through the bed co-currently to one another to produce a fluid waste having an adsorbate concentration substantially greater than said fluid feed at a waste exit wherein, during said regeneration stage,
- there is created in the bed an RW front having a first velocity, said RW front being bounded on its downstream side by bed conditions characteristic of equilibrium between the adsorbent material and the fluid waste and on its upstream side by bed conditions characteristic of equilibrium between the adsorbent material and the hot regenerant fluid, and
- upstream of said RW front, there is created in the bed by the introduction of said cooling fluid having a lower temperature than said regenerant fluid, a thermal front having a velocity greater than said first velocity, said thermal front being bounded on its downstream side by high temperature conditions and on its upstream side by low temperature conditions,
- wherein the improvement comprises:
- introducing said cooling fluid into the bed before the midpoint of the RW front exits the bed to produce, during a portion of the cooling fluid flow, fluid waste at said waste exit having an adsorbate concentration substantially greater than the adsorbate concentration of said feed.
A method of operating an adsorption bed having an adsorbent material disposed within a housing defining a feed entrance, a fluid flow path, and a product exit, said adsorbent material being of the type used to reduce the concentration of an adsorbate carried by a fluid feed, said method including cycling the bed through an adsorption stage wherein the fluid feed is passed through the bed and a fluid product of reduced adsorbate concentration is collected at the product exit, and a thermal regeneration stage wherein a hot regenerant fluid of temperature T.sub.R and a cooling fluid are serially passed through the bed co-currently to one another to produce a fluid waste having an adsorbate concentration substantially greater than said fluid feed at a waste exit, said fluid waste having a maximum adsorbate concentration, Y.sub.MAX, wherein the improvement comprises:
- switching the flow of fluid entering the bed during regeneration from hot regenerant fluid to cooling fluid after the adsorbate concentration in the fluid falls below about 0.5 Y.sub.MAX at a selected point within the bed whereby during a portion of the cooling fluid flow the adsorbate concentration of said fluid waste exiting the bed is substantially equal to Y.sub.MAX.
Dependencies are inferred from the claim text.