Question

Question 4 Consider the following combustion reactor that is at a steady state as shown in Figure 4, where HCl reacts with 35 mol% excess air to form chlorine (CI) and water (H20). You may assume that the air contains 21% oxygen (O2) and 79% nitrogen (N2) (on a mole basis). 20 kmol HCI 4HCI + O2 + 2Cl2 + 2H,0 n, HCI ₂0₂ п, СІ, na H2O ng N₂ Air (O2 and N2) 35% Excess Figure 4. A combustion reactor at steady state a) Calculate the number of degrees of freedom of the combustion reactor. (15 marks] b) Using the general material balance equation, determine the number of moles of oxygen (O2) leaving the combustion reactor, if the conversion of HCl is 80%. [15 marks]

Answer 1

16 17 18 19 20 21 22 23 24 25 26 27 1 2 3 4 5 6 7 8 9 10 11 12 13 M A R 2145678910 11 12 13 14 15 16 17 18 19 21 21 21 20 27 35 20 30 WTWTFSSMTWTFSS 0 31 A WTWTFSS MTWTFSS N 19 01 FRIDAY FEBRUARY 052-333. WK05 SATURDAY FEBRUARY WK 05.033-332 02 119 DO -u-st I - R & 1 akulation of degrees of freedom Hel 9 vano of unknown snoof species I a no of indipendent reactions R2 noof relations Products n Hel n'oz n cl n H2O n Na 10 ANY 11 DOF 11 5 - 5+1 12 Neumbes unknowns = 5 (u Hel, no₂, nela, nH20,0 Hz) in the system tem soketion can be determined 1 de Conversion soy. number of species 5 (Hd, oor Cl2, H₂0, N2) Number of indipendent reactions ! m 4mot 4 HCl + o2 acl2 + H₂O 4 Helt O2 → 2ch tal20 4 amol Hel requires Imoloa to produce amolcle and s Number of relation = 1 imol H2O 357. excess air to form cland 16 Imot air contains 0.79 mol Na and a 21 motor i. Degrees of freedom (DOF) = Namber of unknown-Number of species t Number of indipendent reactions - Number of relation : Imol of oxygen present in 1 mol of ar 0.21 Oss H161 mol 4 ay has mal 9 SUNDAY 03 Stotiometric ratio of eron Dor uts 2019 Hel 48 02 2019

na wolar Cont 6/8E9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 2 21293031 MTWTFSS MTWTFSS MONDAY FEBRUARY N 04 M 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 A 2127 21 331 MTWTFSSMTWTFSS 19 19 TUESDAY FEBRUARY WK 0.03639 05 DS5-330WK05 : 20 mot Hel Product formed &mot cl2 gmol H₂O 5 mol oa requires 5 mol Only gen is present in the founu 5x4 761 mol of air, * 23.80 mot of air Ja 85% excess air provided 9 10 unreacted O2 6.749 - 4 = 2-749 mot of unreacted 02 unreacted Ne= 25.34 moteno Na. 10 11 13 Airsupplied = 1.35 x 23.8 = 32.142 mot fair supplied 20-16= 4 moles of unreacted Hel 12 12 - Number Feed contains : - 20mol Hel - 32-142 molofair 32-1420 19 = 25.39 meln of moles of oxygen leaving the reactor = 24 = 2-149 mols 2 32-142X0-21-6-749 mslo • Conversion is 80% 5. Hel converted = 20x0.8 = 16 moles of tel converted 5 8 Remaining unreacted Hel= 20-16 4molta 16 mol Hel Het + 102 + Amol O2 2 cl2 + 2H2O - gmolcl2 tsmot B H2O from 1 stotione fric ratio : 44:2:2 2019 2019