a) b) A coal fired power plant produces 30 kmol s-1 of exhaust gas with a composition of 12 mol% CO2, 16 mol% H2O, 4 mol% O2 and the balance N. A CCGT plant of the same power rating produces 41.5 kmol/s of exhaust with a composition of 7 mol% CO2, 5 mol% H2O, 13 mol% O2 and the balance is N2. (i) Treating both exhaust streams as ideal gases, what is the minimum work (kJ kmolco21) for the isothermal and isobaric separation of CO2 from the flue gas mixture such that 90% of the CO2 is captured and produces a CO2 product stream of 98 mol% purity? [30 Marks] (ii) Given this initial answer, what does this imply for the cost of CCS applied to gas- as opposed to coal-fired power plants in terms of both tco21 captured and MWh-1 of low carbon energy generated? [20 Marks] If CCS on power or industry is not deployed in the near term, it is increasingly recognised that it will be necessary to remove CO2 from the air, with Direct Air Capture (DAC) being proposed as one method. With relation to the solution of the gas CCS plant in Part A, determine: (i) How much air do you need to treat in order to capture the equivalent amount of CO2 as the gas CCS plant, given that there are currently 400ppm CO2 in air? [5 Marks] (ii) What is the specific work (kJ kmol-1 of CO2) required for this option, given that ambient air is available at 15C? [30 Marks]