https://nova.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:26896 10bar) where the kinetic rate of NO oxidation to NO₂ increases less with pressure increase. Capture of NOₓ was increased from 55% to 75% by doubling the residence time in the compressor and could be further extended to 83% by increasing back end pressure from 24bar to 30bar. Lowering the temperature during compression produced the greatest NOₓ and Hg capture. Overall, the results indicate that capture of mercury during compression occurred as a consequence of high pressure, longer residence time and concentration of NO₂.]]> Wed 11 Apr 2018 15:32:06 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:8033 Sat 24 Mar 2018 08:36:48 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:26105 total and Hg⁰ with SOₓ removal. Total mercury emissions in oxy-firing measured a maximum of 6–7 μg/m³ of which 89% was in oxidised form (Hg²⁺). The use of low NOₓ burners had an overriding influence on the mercury measurements reducing the total mercury levels to 0.13 and 0.15 μg/m³ (air, oxy respectively) with no Hg²⁺ being measured. The SO₃ concentrations were also lower than expected, estimated at ∼0.5–0.8 ppm (based on a practical estimate of 1% conversion of SO₂). Overall mercury capture in either operating mode was estimated at 92–93% for the existing burners and 98–99% with the low NOₓ burners used (being 2 of the 4 burners operating). Total SOₓ captured from the flue gas was 16% in oxy-mode and 19% in air firing. These findings suggest that operational conditions have a primary impact on capture of Hg and SOₓ during transitions with a secondary impact of firing mode (i.e. air or oxy).]]> Sat 24 Mar 2018 07:39:52 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:22742 x and Hg can also be removed as part of the liquid condensate. This work presents field tests conducted on the condensates to determine the stability of captured NO_x and Hg species when depressurised. These tests involved sampling liquid condensate directly into a customised aeration vessel and measuring the evolved gases over an 8–12 h period. The low-pressure condensate (∼4 bar) showed that 3–18% of captured NO_x species and 0.5–1.2% of the Hg were volatile, while the high-pressure condensate (24 bar) re-emitted 2–68% of captured NO_x and 0.05–12.5% of the captured Hg. These tests showed that volatile Hg was related to volatile NO_x and that this volatility of condensates changed with time as the compression plant operated from start-up. Equilibrium calculations of HNO₂ in the gas and liquid phases supported the volatility measurements, suggesting that the rate of oxidation of HNO₂ to HNO₃ in the condensed phase is slow. Overall, the conditions which favoured NO_x stability in the condensates, namely longer residence and higher pressure also favoured Hg stability. This work has shown that emissions from an oxy-fuel compression plant must include those emanating from depressurised condensates and suggest that the re-emitted species may not the same as in typical combustion flue gas, but the result of higher-pressure conversion.]]> Sat 24 Mar 2018 07:12:24 AEDT ]]>