Separation process

Abstract

Abstract A separation process which may be used for example to separate aromatic compounds from naphthenic and paraffinic components in a hydrocarbon feed or for separating normal and non-normal hydrocarbons comprises introducing a feed containing "solvent" and "solute" into an adsorption zone containing adsorbent which is selective for the solute and carries adsorbed solvent, and collecting an adsorption effluent lean in solute; flowing a displacing agent into the zone and collecting a desorption effluent containing desorbed solvent and solute; and introducing a portion of the adsorption effluent into the zone in the same direction of flow as the displacing agent and collecting the displaced displacing agent and a product rich in solute. The examples relate to separation of hexane and benzene at 650 DEG F. and 1 atmos. pressure on 10X molecular sieve using ammonia as displacing agent. Generally there may be used the A and X series of sieves, for example <PICT:1110133/C4-C5/1> the 5A and 13X sieves, and the displacing agent is preferably a compound NR1R2R3 where R1R2, R3 are hydrogen or C1-C5 alkyl radicals: CO, NO, SO2, CO2, C1-C5 alcohols, glycols, methyl and ethyl chloride, methyl fluoride or nitromethane. In the two bed process of Fig. 2, feed entering at 101 is heated in 102 and passes into bed 107. The first cut of adsorption effluent which is solvent-rich is collected in 114. The second cut passes through valve 113 to bed 108 for the second desorption step in this bed. In the first desorption step in bed 108 displacing agent from 115 is passed to the bed through line 119; the material displaced from the bed is recycled to feed by line 129. During the second desorption step in bed 108 the effluent passes to 130; the separated displacing agent is returned from 130 to storage at 115 and a solute-rich stream recovered at 132. Figs. 1 ad 3 (not shown) relate respectively to a single-bed and a three-bed process; Fig. 4 (not shown) to a moving bed process.

Inventors

• 👤 Jerry L Robertson
• 👤 William R Epperly

Bibliographic Details