[...]... 17 . 01 N2 63.99 – C3H8 2.5 C3H8 þ 5O2 ¼ 3CO2 þ 4H2O C4H10 16 .5 2C4H10 þ 13 O2 ¼ 8CO2 þ 10 H2O Total 10 0 2:5 Â 5 ¼ 12 :5 1 16:5 Â 13 ¼ 10 7:25 2 10 2.74 So 1 m3 of butane requires 1. 0274 m3 of oxygen – near enough 1 m3  Butane/air 1: 027 Â 10 0 ¼ 4:89 m3 of air or roughly 5 m3 21 PRODUCTS OF COMBUSTION It does not follow that because 1 m3 of natural gas requires 9.8 m3 of air, the volume of products will be 1. .. 1 þ 9.8 ¼ 10 .8 m3 of products of combustion (Tables 2.5–2.7) For example, – 0.6 90.0 5.3 1. 0 0.4 10 0.0 CO2 CH4 C2H6 C3Hg C4H10 Total – 10 5.8 0.6 90 Â 1 ¼ 90:0 1 5:3 Â 4 ¼ 10 :6 2 1 Â 3 ¼ 3:0 1 0:4 Â 8 ¼ 1: 6 2 Carbon Dioxide 2 01. 9 90 Â 2 ¼ 18 0:0 1 90 Â 2 ¼ 18 0:0 1 1 Â 4 ¼ 4:0 1 1 Â 4 ¼ 4:0 1 Water Vapour Products of Combustion Note that the 0.6 m3 of carbon dioxide present in the 10 0 m3 of gas before... that in natural gas there is 90 m3 of methane in each 10 0 m3 of the gas The equation is: or CH4 1 volume þ þ 2O2 2 volumes ¼ ¼ CO2 1 volume þ þ 2H2 O 2 volumes So each 1 m3 of methane requires 2 m3 of oxygen and produces 1 m3 of carbon dioxide and 2 m3 of water vapour Therefore, 90 m3 of methane will require 18 0 m3 of oxygen and produce 90 m3 of carbon dioxide and 18 0 m3 of water vapour The oxygen requirements... between the number of molecules and the volume of gases, the equation shows the volumes of gases involved So, FIGURE 2.4 Combustion of methane 18 Combustion FIGURE 2.5 The volumes of gases involved in the combustion of methane CH4 1 volume methane þ requires 2O2 2 volumes oxygen ¼ and gives off CO2 1 volume carbon dioxide þ and 2H2 O 2 volumes water vapour This is true for any volume of methane Figure... ¼ 7:5 1 16:5 Â 8 ¼ 66:0 2 Carbon Dioxide 92.5 2:5 Â 4 ¼ 10 :0 1 16:5 Â 10 ¼ 82:5 2 Water Vapour 85:9 Â 4 ¼ 343:6 1 12:0 Â 6 ¼ 36:0 1 1:5 Â 6 ¼ 4:5 2 0:6 Â 10 ¼ 3:0 2 387 .1 85:9 Â 3 ¼ 257:7 1 12:0 Â 6 ¼ 36:0 1 1:5 Â 4 ¼ 3:0 2 0:6 Â 8 ¼ 2:4 2 299 .1 Products of Combustion Water Vapour Carbon Dioxide Products of Combustion 22 Combustion Products of combustion C3 H8 1 volume þ 5O2 ¼ þ 5 volumes ¼ 6 volumes... 1 C3H6 12 .0 2C3H6 þ 9O2 ¼ 6CO2 þ 6H2O 12 Â 9 ¼ 54:0 2 C2H6 1. 5 2C2H6 þ 7O2 ¼ 4CO2 þ 6H2O C4H10 0.6 2C4H10 þ 13 O2 ¼ 8CO2 þ 10 H2O 1: 5 Â 7 ¼ 5:25 2 0:6 Â 13 ¼ 3:9 2 Total 10 0 492.65 So 1 m3 of propane requires 4.926 m3 of oxygen – near enough 5 m3 Table 2.4 Oxygen Requirement – Butane/Air Constituent Percentage by Volume Chemical Equation for Combustion Volumes of Oxygen Required to Burn O2 17 . 01 – 17 . 01. .. Since the atmosphere consists of 21% oxygen the air requirements for the complete combustion of 1 m3 of gas are as follows:  Natural gas 2:06 Â 10 0 ¼ 9:8 m3 of air or roughly 10 m3 21  Commercial propane 10 0 ¼ 23:45 m3 of air or roughly 24 m3 4:926 Â 21 Table 2.2 Oxygen Requirement – Natural Gas Constituent Percentage by Volume Chemical Equation for Combustion Volumes of Oxygen Required to Burn –... 90 Â 2 ¼ 18 0:0 1 5:3 Â 7 ¼ 18 :6 2 5:3 Â 7 ¼ 18 :6 2 5:3 Â 7 ¼ 18 :6 2 CH4 90.0 C2H6 5.3 2C2H6 þ 7O2 ¼ 4CO2 þ 6H2O C3H8 1. 0 C3H8 þ 5O2 ¼ 3CO2 þ 4H2O C4H10 0.4 2C4H10 þ 13 O2 ¼ 8CO2 þ 10 H2O Total 10 0 So 1 m3 of natural gas requires 2.062 m3 of oxygen – near enough 2 m3 206.2 20 Combustion Table 2.3 Oxygen Requirement – Commercial Propane Volumes of Oxygen Required to Burn Constituent Percentage by Volume. .. provide the 2.06 m3 of oxygen required to burn 1 m3 of natural gas, we needed 9.8 m3 of air The difference, 9.8 – 2.06 ¼ 7.74 m3, is nitrogen So, when 1 m3 of natural gas is burned, the total volume of gases which are leaving the combustion chamber of the appliance is: Carbon dioxide 1. 058 Water vapour 2. 019 Nitrogen from gas 0.027 Nitrogen from air 7.74 Total 10 .844 m3 or roughly 11 m3 For commercial... total volume The 2.7 m3 of nitrogen will need to be added into the final total 2C4 H10 þ 13 O2 ¼ 8CO2 þ 10 H2 O C3 H8 þ 5O2 ¼ 3CO2 þ 4H2 O 2C2 H4 þ 7O2 ¼ 4CO2 þ 6H2 O CH4 þ 2O2 ¼ CO2 þ 2H2 O – Chemical Equation for Combustion 2.7 Percentage by Volume N2 Constituents Table 2.5 Products of Combustion – Natural Gas Products of combustion 21 85.9 12 .0 1. 5 0.6 10 0.0 C3H8 C3H6 C2H6 C4H10 Total 16 .5 10 0.0 C4H10 . Energy 11 1 6 Pressure and Gas Flow 14 7 7 Control of Pressure 18 1 8 Measurement of Gas 207 9 Basic Electricity 240 10 Transfer of Heat 288 11 Gas Controls 311 12 . w0 h1" alt="" Tolley’s Basic Science and Practice of Gas Service Gas Service Technology Volume 1 This page intentionally left blank Tolley’s Basic Science