Most hydrogen produced today is made via steam-methane reforming, a process in which high temperature (700 to 1000C) steam is used to produce hydrogen from a methane source, such as natural gas. In such a process, methane reacts with steam under high pressure ( 3 to 25 bar) in the presence of a nickel based catalyst to produce hydrogen, carbon monoxide, and a relatively small amount of carbon dioxide. However, steam reforming is an endothermic reaction so the tail gas which consists of 10.0 vol\% CH4,15.0 vol\% CO,25.0 vol\% H2 and 50.0 vol\% CO2 leaving the pressure swing adsorption unit is utilised as a fuel in the reformer. The standard heats of combustion of CH4(g),CO(g) and H2(g) as well as heat capacities (T is in C) of H2O(I,g),CH4(g),CO2(g),CO(g),H2(g),O2(g) and N2(g) are given below: CH4(g)+2O2(g)CO2(g)+2H2O(l)Hc0=890.36CO(g)+1/2O2(g)CO2(g)Hc0=282.99kJ/molH2(g)+1/2O2(g)H2O(l)Hc0=285.84kJ/molkJ/molCp.H2O(i)=75.4103Cp,H,O(g)=33.46103+0.6880105T+0.7604108T23.5931012T3kJ/molCCp.CH4(9)=34.31103+5.469105T+0.3661108T211.01012T3kJ/molCCp..(Co2(g)=36.11103+4.233105T2.887108T2+7.4641012T3kJ/molCCp,co(g)=28.95103+0.4110105T+0.3548108T22.2201012T3kJ/molCCp,.02(g)=29.10103+1.158105T0.6076108T2+1.3111012T3kJ/molCC.N2(g)=29.0103+0.2199105T+0.5723108T22.8711012T3kJ/molC The heat of vaporisation of water at 100C is 40.656kJ/mol and the atomic weights of H, C and O are, respectively, 1,12 and 16. (a) What is Hr0 for 2CO2(g)+4H2O(l)2CH4(g)+4O2(g) ? [3 marks] (b) Calculate the lower heating value of CH4(g) in kJ/kg. [6 marks] (c) When 100mol/s of tail gas at 25C combusted completely with theoretical amount of air preheated at 300C in the reformer, estimate the maximum heat released when the products of combustion leave the reformer at 1000C. [8 marks] (d) List three factors that will have a significant effect on the maximum heat released and briefly explain your answers. [3 marks]