Refineries are a source of emissions of volatile hydrocarbons that contribute to the formation of smog and ozone. Fugitive emissions of hydrocarbons are difficult to measure and quantify. Currently these emissions are estimated based on standard emission factors for the type and use of equipment installed. Differential absorption light detection and ranging (DIAL) can remotely measure concentration profiles of hydrocarbons in the atmosphere up to several hundred meters from the instrument. When combined with wind speed and direction, downwind vertical DIAL scans can be used to calculate mass fluxes of the measured gas leaving the site. Using a mobile DIAL unit, a survey was completed at a Canadian refinery to quantify fugitive emissions of methane, C 2ϩ hydrocarbons, and benzene and to apportion the hydrocarbon emissions to the various areas of the refinery. Refinery fugitive emissions as measured with DIAL during this demonstration study were 1240 kg/hr of C 2ϩ hydrocarbons, 300 kg/hr of methane, and 5 kg/hr of benzene. Storage tanks accounted for over 50% of the total emissions of C 2ϩ hydrocarbons and benzene. The coker area and cooling towers were also significant sources. The C 2ϩ hydrocarbons emissions measured during the demonstration amounted to 0.17% of the mass of the refinery hydrocarbon throughput for that period. If the same loss were repeated throughout the year, the lost product would represent a value of US$3.1 million/yr (assuming US$40/bbl). The DIAL-measured hourly emissions of C 2ϩ hydrocarbons were 15 times higher than the emission factor estimates and gave a different perspective on which areas of the refinery were the main source of emissions. Methods, such as DIAL, that can directly measure fugitive emissions would improve the effectiveness of efforts to reduce emissions, quantify the reduction in emissions, and improve the accuracy of emissions data that are reported to regulators and the public.

10, gasification kinetics of chars from two Alberta coals (Obed Mountain, high volatile bituminous and Highvale, subbituminous) have been studied using a thermogravimetric analyzer (TGA) and a fixed bed reactor. Charification and gasification reactions were performed sequentially in both the TGA instrument and in the fixed bed reactor to simulate real gasifier operating conditions. TGA and fixed bed data were processed numerically to evaluate the kinetic rate of CO, gasification of the chars. Calculated gasification kinetics could be correlated using both the volume reaction and the grain models. Activation energies of the kinetic rate constants were near 200 Wlmol for both Highvale and Obed Mountain coal chars using the TGA data. The activation energies calculated for the Obed Mountain coal char using the fixed bed reactor were about 250 kllmol. For all the cases studied the calculated activation energies were nearly the same for both the volume and grain reaction models.

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amounts of oxygen in the saturate and aromatic fractions. They proposed that oxidation of bitumen at low temperatures involves conversion of original resins to asphaltenes with simultaneous conversion of oils to resins. These authors suggested that in these processes oxygen is for the most part a catalyst for condensation reactions, being initially incorporated as labile functional groups that promote these reactions and subsequently eliminated as water. Our chemical kinetic model is consistent with this interpretation, indicating a weak dependence of the rate of depositional processes on oxygen pressure and a stronger effect of pressure of oxygen on the rate of combustion processes. The increase in saturates and decrease in polyaromatic and polar fractions that we observed in the produced oil relative to the original bitumen, in combination with the increasing aromaticity (decreasing molar H/C ratio) of cokes produced with increase in temperature, also support this interpretation. Acknowledgment. We are grateful to D. D. McIntyre for performing chromatographic separations and for many helpful discussions. We also thank Y .-M. Xu for preparation of the calorimetric sample, and Z.-L. Zhang and J.F. Smith for much good advice. We thank the Alberta Oil Sands Technology and Research Authority for support of this and related research.The tars from five hydropyrolysis testa of Highvale (subbituminous, Alberta) coal were studied to determine the effects of reaction severity on concentrations of structural groups. The yields of gases and vapors (carbon oxides + light hydrocarbons + benzene, toluene, and xylene) were used as an internal measure of reaction severity for tars produced from an entrained flow reactor operated at 6 0 0 0 "C, 7 MPa hydrogen pressure, and 0.5-5 s residence times. The structural groups in the tars were estimated by combining data from ' H NMR, ' % NMR, and infrared spectroscopy, nitrogen titration, and elemental analysis. The samples processed at higher severity showed overall concentration increases in aromatic groups and decreases in aromatic side chains, naphthenic rings, and oxygen-containing structures relative to low-severity tars.

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