Adsorbent bed for mercaptan removal with increased hydrothermal stability

A thermal swing adsorption method to perform mercaptan removal and water removal in a single adsorbent bed, the method comprising:

• directing a gas feed stream having an initial mercaptans mole fraction and an initial water mole fraction toward the adsorbent bed, the adsorbent bed comprising:
• a first adsorbent layer to remove mercaptans and water from the gas feed stream, the first adsorbent layer comprising one or more of an amorphous silica adsorbent, an amorphous silica-alumina adsorbent, or a high-silica zeolite adsorbent;
• and
• a second adsorbent layer downstream from the first adsorbent layer to remove remaining mercaptans and/or water from the gas feed stream, the second adsorbent layer comprising a zeolite that is less hydrothermally stable than the adsorbent of the first adsorbent layer and selected from one or more of zeolite A or zeolite X,
• wherein a weight percent (wt %) of the first adsorbent layer with respect to a total weight of the first adsorbent layer and the second adsorbent layer, is greater than 50 wt %, and
• wherein the gas feed stream has a reduced mercaptans mole fraction when the gas feed stream reaches the second adsorbent layer that is maintained for at least 90% of the duration of each adsorption step of an adsorption cycle.

A method of removing water and mercaptans from a gas feed stream comprising hydrocarbons and water during an adsorption step of an adsorption cycle, the method comprising:

• directing the gas feed stream having an initial mercaptans mole fraction and an initial water mole fraction toward an adsorbent bed, the adsorbent bed comprising:
• a first adsorbent layer to remove water and mercaptans from the gas feed stream, the first adsorbent layer comprising one or more of an amorphous silica adsorbent or an amorphous silica-alumina adsorbent;
• and
• a second adsorbent layer downstream from the first adsorbent layer to remove remaining water, the second adsorbent layer comprising a zeolite that is less hydrothermally stable than the adsorbent of the first adsorbent layer and selected from one or more of zeolite A or zeolite X,
• wherein a weight percent (wt %) of the first adsorbent layer with respect to a total weight of the first adsorbent layer and the second adsorbent layer, is greater than 50 wt %, and
• wherein the gas feed stream has a reduced mercaptans mole fraction and a reduced water mole fraction when the gas feed stream reaches the second adsorbent layer, wherein the reduced mercaptans mole fraction is maintained for at least 90% of the duration of the adsorption step, and
• wherein the reduced mercaptans mole fraction is less than or equal to about 90% of the initial mercaptans mole fraction, and wherein the reduced water mole fraction is less than about 10% of the initial water mole fraction.