of the fuel’s energy content. While sulfur reduction in diesel fuel requires capital equipment, the energy and emission impacts are relatively small.
Emissions associated with reformulated diesel production were estimated to correspond to those for generating electric power for the additional energy input less a credit for the reduction in fuel input to the refinery. Emissions for producing electric power are discussed in Section 4.8.
Table 4-17: Model Energy Inputs for Producing Reformulated Diesel
150 ppm Diesela
20 ppm Dieselb
Crude Oil (kWh/day)
Electric Power (MWh/day)
a MathPro Case 8.
b MathPro Case 9a.
c Electricity is counted as 9000 Btu/kWh.
4.3 LPG Processing from Natural Gas
The study evaluated the emissions attributable to LPG production. These emissions can be associated with the process for converting raw natural gas into market dry gas since LPG components are removed from the gas as waste products. The propane (over 97 percent), ethane, butane, and methane are removed from natural gas during the extraction process. In 1998, 561 million metric tonnes of gas were withdrawn from oil and gas wells. Of this, approximately 400 million tonnes were produced as dry gas, while 14 million tonnes of LPG were extracted. The LPG produced has been calculated by examining the DOE Energy Information Administration’s inventories of gas withdrawn, portions removed during production, and portions removed during extraction. Methane, light hydrocarbons, and other gases are used for pressurizing gas and are lost due to venting and flaring during production. In addition, hydrocargons is removed during the liquid extraction process and fugitive losses occur. The EIA inventories show that only 29 percent of the extracted liquids is propane. Since this is the main component of LPG, the quantity of LPG produced is much less than the total hydrocarbons extracted.