Regeneration schemes for a two-stage adsorption process for Claus tail gas treatment

A Claus tail gas treatment system for sulfur recovery, the Claus tail gas treatment system comprising:

• a hydrogenation reactor, the hydrogenation reactor configured to receive a Claus tail gas and to convert sulfur-containing compounds to hydrogen sulfide such that a hydrogenated gas stream is produced, wherein the Claus tail gas comprises the sulfur-containing compounds, wherein the hydrogenated gas stream comprises hydrogen sulfide, water, and at least one of:
• carbon dioxide and nitrogen, wherein the hydrogenated gas stream is in the absence of the sulfur-containing compounds other than hydrogen sulfide;
• a quench tower, the quench tower fluidly connected downstream of the hydrogenation reactor to receive the hydrogenated gas stream, the quench tower configured to condense and recover liquid water via a first water condensate stream and to produce a quenched gas stream, wherein the quenched gas stream comprises hydrogen sulfide and at least one of:
• water, carbon dioxide, and nitrogen;
• a first stage adsorption unit, the first stage adsorption unit comprising at least three first stage adsorption vessels fluidly connected in parallel, wherein, during a first stage adsorption cycle, one of the at least three first stage adsorption vessels is fluidly connected downstream of the quench tower to receive the quenched gas stream and adsorb water to produce a first outlet gas stream, wherein, during a first stage regeneration cycle, one of the at least three first stage adsorption vessels desorbs water to produce a first byproduct gas stream, wherein the first outlet gas stream comprises hydrogen sulfide and at least one of:
• carbon dioxide and nitrogen, wherein the first outlet gas stream is in the absence of water, wherein the first byproduct gas stream comprises water;
• and
• a second stage adsorption unit, the second stage adsorption unit comprising at least three second stage adsorption vessels fluidly connected in parallel, wherein, during a second stage adsorption cycle, one of the at least three second stage adsorption vessels is fluidly connected downstream of first stage adsorption unit to receive the first outlet gas stream and adsorb hydrogen sulfide to produce a second byproduct gas stream, wherein, during a second stage regeneration cycle, one of the at least three second stage adsorption vessels desorbs hydrogen sulfide to produce a second outlet gas stream, wherein the second byproduct gas stream is in the absence of hydrogen sulfide, wherein the second outlet gas stream comprises hydrogen sulfide.