US PATENT SUBCLASS 585 / 820
.~ By contact with solid sorbent

Current as of: June, 1999
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585 /   HD   CHEMISTRY OF HYDROCARBON COMPOUNDS

800  DF  PURIFICATION, SEPARATION, OR RECOVERY {7}
820.~ By contact with solid sorbent {7}
821  DF  .~.~> With measuring, sensing, testing, or recycle of sorbate to same sorption zone
822  DF  .~.~> Plural serial sorptions
823  DF  .~.~> Sorbate is nonhydrocarbon or chemically undetermined component, e.g., "color-former", etc. {1}
825  DF  .~.~> With fractional or linear desorption, e.g., chromatography, etc.
826  DF  .~.~> With specified sorbent rehabilitation procedure or agent, e.g., desorbent, etc. {2}
830  DF  .~.~> Sorbent is or contains organic
831  DF  .~.~> Cyclic sorbate

DEFINITION

Classification: 585/820

By contact with solid sorbent:

(under subclass 800) Subject matter wherein a solid mass is used to retain on its surface or inside its pores a constituent of a mixture from which hydrocarbon is to be recovered.

(1) Note. "Solid sorbent" includes but is not limited to diatomaceous earth, kieselguhr, perlite, activated carbon, asbestos, colloidal clays, molecular sieves, silica gel, ion-exchange zeolites, and resins, etc.

(2) Note. Sorption processes depend for their effectiveness upon the shape or chemical composition of the molecules

retained by the solid sorbent. They thus are distinguishable from filtration processes which depend upon a mechanical entrapment of solid particles because of their relatively large size compared to the interstices or spaces between individual elements of a filter. In the case of a filter mechanical brushing, wiping, shaking, etc., will remove the retained particles. Sorption processes which depend for their effectiveness upon molecular shape generally employ a "molecular sieve" which usually is a natural or synthetic metal aluminum silicate or similar material whose atoms are arranged in a crystal lattice in such a way that there are a large number of small pores interconnected by smaller openings or pores of precisely uniform size. The most common molecular sieves are zeolites, a class or natural or manufactured hydrated silicates of aluminum and either sodium or calcium or both, of the type Na2O.A12O3.nSiO2.xH2O. They will accept and retain molecules that are small and/or slender enough to pass through the pores, thus separating them from a mixture with larger or bulkier molecules.

Other sorption processes separate a constituent from a fluid mixture containing such constituents in a "quasi-chemical" manner. The action in most instances is that of selective retention, e.g., the sorbent interacts with and thereby retains only the part of the fluid mixture for which it has the greatest affinity. The retained portion cannot be removed by mechanical action but generally requires heating or use of a stripping or desorbing fluid.

(3) Note. Ion exchange is a chemical metathesis process in which ions are chemically transferred from a usually liquid material to a usually solid separatory substance or exchanger which has a chemical structure of loosely bound ions. The exchanger substance can usually be regenerated by passing another material through it to elute the exchanged ions and replace them with the original kind of loosely bound ions. When a patent calls a process involving an ion exchanger "sorption", the process is placed in these subclasses (820+), but when the true mechanism of the separatory procedure appears to be ion exchange, it is cross-referenced to subclasses 833+ below.

SEE OR SEARCH CLASS

95, Gas Separation: Processes, 90+, for processes of gas separation using solid sorbents.

203, Distillation: Processes, Separatory,

41, for separatory distillation process including the step of passing the distillate material through a solid sorbent.

208, Mineral Oils: Processes and Products,

310, for mineral oil fractionation processes which include adsorption.

210, Liquid Purification or Separation,

656+, and 660 for liquid purification by ion exchange or sorption, wherein the process is directed to the purification of water or a number of compounds, one of which is water, or if the claims are broad, as to the liquid purified. Where claims or disclosure specific to hydrocarbon purification indicates classification in this class, subclasses (820+) and that patent contains claims to the separation of any other liquid or fluid mixture, the patent is cross-referenced to Class 210.