SELECTIVE REMOVAL OF NITROGEN FROM NATURAL GAS BY PRESSURE SWING ADSORPTION

摘要

A pressure swing adsorption process for the separation of nitrogen from natural gas utilizes two separate pressure swing adsorption stages, the first containing a hydrocarbon-selective adsorbent and the second containing a nitrogen-selective adsorbent. In the process, the product stream from the first pressure swing adsorption unit contains a natural gas stream having a reduced hydrocarbon content and the product stream from the second pressure swing adsorption unit is a natural gas stream having a reduced nitrogen concentration. The product from the second pressure swing adsorption unit is used to desorb the hydrocarbons from the first pressure swing adsorption unit so as to add the hydrocarbons, which have heat value to the product natural gas stream. Periodically, heating the nitrogen-selective adsorbent with heated product stream from the second pressure swing adsorption unit has been found to improve the capacity of the nitrogen-selective adsorbent to adsorb nitrogen.