Adsorption process for treating natural gas
A process of treating a natural gas stream is provided comprising sending natural gas stream through a first adsorbent bed to remove water and heavy hydrocarbons (C8+) to produce a partially treated gas stream in which the first adsorbent bed is regenerated by a temperature swing adsorption process and then sending the partially treated gas stream through a second adsorption bed to remove carbon dioxide and lighter hydrocarbons (C7−) to produce a purified natural gas stream wherein said second adsorption bed is regenerated by a temperature pressure swing adsorption process.
1. A process of treating a natural gas stream comprising
sending said natural gas stream through a first adsorbent bed to remove water and heavy hydrocarbons (C8+) to produce a partially treated gas stream wherein said first adsorbent bed is regenerated by a temperature swing adsorption process; and
sending said partially treated gas stream through a second adsorption bed to remove carbon dioxide and lighter hydrocarbons (C7−) to produce a purified natural gas stream wherein said second adsorption bed is regenerated by a temperature pressure swing adsorption process.
2. The process of claim 1 wherein said natural gas stream comprises less than about 3 vol % carbon dioxide.
3. The process of claim 1 wherein a closed loop or semi-closed loop regeneration gas stream is used to regenerate said second adsorbent bed.
4. The process of claim 3 wherein a semi-closed loop regeneration gas stream is used to regenerate said second adsorbent bed.
5. The process of claim 1 wherein said temperature pressure swing adsorption process comprises a series of steps in order comprising adsorption, co-current depressurization, closed-loop heating, a purge with heating, a purge without heating, repressurization of the adsorbent bed and cooling with feed and then withdrawal of product.
6. The process of claim 1 wherein said temperature pressure swing adsorption process comprises a series of steps in order comprising adsorption, co-current depressurization, a first closed loop heating step and a second closed loop heating step, a depressurization step, a purge without heat, repressurization and cooling with feed and withdrawal of product.
7. The process of claim 5 wherein a portion of said product is used in said purge without heating step.
8. The process of claim 6 wherein a portion of said product stream is heated and sent through said adsorbent bed.
9. The process of claim 8 wherein a stream exiting said adsorbent bed is sent into said adsorbent bed or into a second adsorbent bed.
10. The process of claim 5 wherein said heating step is at a higher pressure than said purge step.