| 摘要 |
<p>D-12129 n-PARAFFIN - ISOPARAFFIN SEPARATION PROCESS Normal paraffins are isolated from a feedstock mixture of normal and non-normal paraffins in the vapor phase at superatmospheric pressure using an adsorption system comprising at least four fixed adsorption bed containing a 5 Angstrom molecular sieve adsorbent, each of which cyclically undergoes the stages of (a) adsorption-fill, (b) adsorption, (c) void space purging, and (d) purge desorption. The improvement of the present process comprises recycling in the vapor phase in combination with feedstock the mixture of isoparaffin and normal paraffins purged from one bed of the system during stage (c) to another bed of the system undergoing stage (b). In conventional practice the void space contained hydrocarbons purged from each bed during stage (c) was cooled, separated from the purging gas, pumped to a holding tank in the liquid phase and thereafter reheated to form the vapor phase before being admixed with fresh feedstock for further treatment. S P E C I F I C A T I O N</p> |
