Other Fuels (MJ)
Energy Fuel Content of Production Delivered Feedstock
& Delivery Fuel Transport Energy Total (MJ)
3.74 50.38 0.07 26.49 115.90 3.80 19.59 0.14 5.73 90.85 2.61 5.94 0.24 13.70 80.23 1.41 11.75 0.01 36.42 72.37
1.83 7.48 0.07 29.62 80.82 3.32 12.77 0.13 5.84 74.78 3.37 13.56 0.14 5.84 76.10
Polymethyl methacrylate (beads)
Polymethyl methacrylate (sheet)
Polyols (polyurethane precursor)
Polystyrene (general purpose)
Polystyrene (high impact)
Polyvinyl chloride (emulsion) (PVC)
Polyvinyl chloride (suspension)
TDI2 (polyurethane precursor)
0.07 26.86 107.65
0.08 24.91 129.10
0.10 20.74 109.82
0.44 49.64 153.27
^Totals may not agree because of rounding. These data are based on average European practices during the 1990s. iMDI = Diphenylmethane diisocyanate.
2TDI = Tolylene diisocyanate.
exhibits a consumption of 34.81 MJ of oil feedstock and 13.70 MJ of gas feedstock. If the calorific values of oil and gas are 45 and 54 MJ/kg, respectively, these data correspond to 34.81/45 = 0.774 kg oil and 13.70/54 = 0.254 kg gas—a total feedstock input of 0.774 + 0.254 = 1.028 kg hydrocarbon feedstock per kilogram polymer. Suppose now that all of this feedstock were to be supplied as gas rather than a mixture of oil and gas. The gas feedstock rises to 54 x 1.028 = 55.15 MJ, and the gas production energy rises from 2.61 to 8.10 MJ. At the same time, the oil feedstock decreases to zero, and the oil production energy decreases from 0.49 to 0.14 MJ. The overall gross energy therefore increases from 80.23 MJ/kg polymer to 92.37 MJ/kg polymer, an increase of 15%. Conversely, if all of the feedstock had been supplied as oil, then the gross energy would decrease to 76.51 MJ/kg polymer, a fall of 5%. It is generally true that gross energy is always higher when gas feedstock is used, and so any comparison of two polymer production processes must take into account variations in feedstock type.
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