Recycle TSA regen gas to boiler for oxyfuel operations

A method for removing water and at least NO2 from carbon dioxide flue gas comprising water, NOx, O2 and N2 as contaminants, generated an oxyfuel combustion system, said method comprising:

• passing said carbon dioxide flue gas at a first elevated pressure through a first adsorption system that selectively adsorbs water and NO2 to produce dry substantially NO2-free carbon dioxide gas, said first adsorption system comprising at least one adsorbent bed;
• purifying said substantially NO2-free carbon dioxide gas below 0° C. to produce purified carbon dioxide as a liquid and carbon dioxide-lean vapor comprising at least a major portion of said O2 and N2;
• recovering carbon dioxide and O2 from said carbon dioxide-lean vapor at a second elevated pressure to produce carbon dioxide-rich gas comprising O2 and carbon dioxide-depleted gas that is rich in N2;
• using at least a portion of said carbon dioxide-rich gas to regenerate at least a portion of said adsorbent bed(s) of said first adsorption system and produce NO2-enriched regeneration gas comprising O2 and water;
• and
• recycling at least a portion of said NO2-enriched regeneration gas to said oxyfuel combustion system.

An apparatus for removing at least NO2 from a carbon dioxide feed gas comprising NOx and at least one non-condensable gas as contaminants, said apparatus comprising:

• a first adsorption system for selectively adsorbing at least NO2 from said feed gas at a first elevated pressure to produce at least substantially NO2-free carbon dioxide gas, said first adsorption system comprising at least one adsorbent bed;
• a carbon dioxide purification system for purifying said at least substantially NO2-free carbon dioxide gas to produce purified carbon dioxide and carbon dioxide-lean vapor comprising at least a major portion of said non-condensable gas(es);
• a conduit arrangement for feeding at least substantially NO2-free carbon dioxide gas from said first adsorption system to said carbon dioxide purification system;
• a carbon dioxide recovery system for recovering carbon dioxide from said carbon dioxide-lean vapor at a second elevated pressure to produce carbon dioxide-rich gas and carbon dioxide-depleted gas that is rich in said non-condensable gas(es);
• a conduit arrangement for feeding carbon dioxide-lean vapor from said carbon dioxide purification system to said carbon dioxide recovery system;
• a conduit arrangement for feeding at least a portion of said carbon dioxide-rich gas to said first adsorption system to regenerate at least a portion of said adsorbent bed(s) of said first adsorption system and produce NO2-enriched regeneration gas.