| 摘要 |
<p>Normal paraffins present in high concentrations in light naphtha streams are separated from non-normal paraffins in a four or more bed adsorption system employing, on a cyclic basis, the processing steps of (1) cocurrent purge/adsorption, (2) cocurrent feed/adsorption, (3) countercurrent purge and (4) countercurrent displacement. A processing sequence is employed wherein the cocurrent purge/adsorption and countercurrent purge steps are carried out on a discontinuous basis, while cocurrent feed/adsorption and countercurrent displacement steps are carried out in overlapping sequence. Control means are provided to assure that the high normal paraffin-containing hydrocarbon feed gas and stripping gas are passed to the appropriate beds for said cocurrent purge/adsorption and countercurrent purge steps on a non-continuous basis, said feed gas being continuously fed to a mix drum for mixture with countercurrent purge effluent before removal for use in said cocurrent purge/adsorption step and in said cocurrent feed/adsorption step of the overall four-step process.</p> |
