Pressurized　Oxy-combustion　is　one　of　the　most　promising　technologies　for　carbon　capture,　utilization,　and　storage　(CCUS)　of　coal　utilization.　In　pressurized　oxy-combustion,　the　removal　of　acid　gas　pollutants　and　the　latent　heat　of　moisture　condensation　are　mainly　carried　out　by　an　integrated　direct-contact　wash　column　(DCC).　Recent　studies　have　shown　that　the　inlet　concentration　of　NOx　in　the　column　is　important　for　the　combined　removal　of　NOx　and　SOx,　therefore,　it　is　essential　to　control　the　NOx　emissions　before　the　DCC.　Selective　non-catalytic　reduction　(SNCR)　is　a　promising　and　economical　technology　of　NOx　reduction;　however,　no　study　has　been　conducted　on　SNCR　at　elevated　pressure,　especially　in　pressurized　oxy-combustion.　In　this　paper,　kinetic　modeling　is　carried　out　to　explore　and　optimize　the　NOx　reduction　by　SNCR　in　pressurized　oxy-combustion.　First,　the　detailed　mechanism　used　in　this　study　is　validated　by　the　experimental　results　in　literature.　Based　on　the　validation　of　the　detailed　mechanism,　the　effects　of　different　parameters　including　temperature,　oxygen　concentration,　moisture　content,　NH3　concentration,　and　SO2　concentrations　on　the　SNCR　performance　are　analyzed　at　higher　pressures　in　oxy-combustion　atmosphere.　The　modeling　results　show　that　by　increasing　the　pressure　from　1　atm　to　15　atm,　the　SNCR　de-NOx　efficiency　increased　by　2–3%.　The　width　of　the　optimum　temperature　window　for　maximum　De-NOx　is　broadened　from　1250K　to　1450K　with　increasing　the　pressure　from　1　atm　to　10　atm.　The　increase　of　pressure　has　no　significant　effect　on　thermal　de-NOx　efficiency　with　increasing　the　NH3/NO　ratio.　At　higher　pressure　(10　atm)　the　increase　in　O2　concentration　from　1　to　20%　the　de-NOx　efficiency　decreases　almost　twice　as　much　as　at　1　atm.　The　increase　of　SO2　and　moisture　contents　at　high　pressure　have　no　significant　effect　on　the　de-NOx　efficiency.　Rate　of　production　(ROP)　and　sensitivity　analysis　are　performed　to　determine　the　dominant　reaction　paths　of　de-NOx　in　pressurized-oxy　SNCR　process.　This　study　can　provide　guidance　for　the　process　optimization　of　de-NOx　by　SNCR　in　pressurized　oxy-combustion.　©　2020　Energy　Institute