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911.
Richard D. Siegel 《Journal of the Air & Waste Management Association (1995)》2013,63(11):845-853
An assessment has been made of the state of emission measurement technology to determine whether measurement techniques are sufficiently well advanced to support the development of emission control methods and the implementation of emission standards for aircraft engines. The conclusion drawn from this assessment is that current measurement technology will meet most of the requirements of an emission control program. Certain measurement techniques are inadequate at present but development of improved techniques appears to be proceeding at a satisfactory rate. 相似文献
912.
H.A. Clements Thomas B. McMuIlen Richard J. Thompson Gerald G. Akland 《Journal of the Air & Waste Management Association (1995)》2013,63(12):955-958
Pairs of standard NASN Hi-Vol suspended particulate samplers were operated biweekly at 25 stations (22 urban, 3 nonurban) from August to December 1969 to determine the comparability of paired samples collected under field conditions. The average of each pair of concentration values is taken as the best estimate of the true value; half the difference between each pair of sample values represents the deviation of the pair from that true value. A cumulative distribution of the individual percent deviations from the corresponding true values shows that half the measurements differ from their true value by less than ±4.5%. 90% of the measurements differ from the true value by less than ± 14%. 相似文献
913.
William A. Compton Jack R. Shekleton Thomas E. Duffy Richard T. LeCren 《Journal of the Air & Waste Management Association (1995)》2013,63(9):699-705
Rankine cycle engines have a high potential for meeting the emission levels established by the 1970 amendment to the Federal Clean Air Act for the 1975-76 automobile. This paper discusses a Solar research and development program sponsored by EPA/APCO which demonstrates a full scale 2 million Btu per hour working model of a Rankine cycle engine combustor and controls which can surpass the emission goals established. Special features of the combustor are the unique methods of precisely controlling both the fuel and air to provide optimum flame performance at any engine power level. This paper discusses the special requirements of the Rankine cycle engine and shows why the very wide range of fuel flow required necessitates use. of special techniques in fuel atomization, fuel and air control, and aerodynamics. Sufficient discussion is included to show the design methods that are necessary, in general, to achieve low emissions in continuous flow combustion systems. Emphasis is placed on the importance of interfacing a combustion system with other engine parts if a successful low emission, wide turndown ratio combustor working model is to be achieved. Sufficient discussion on combustion kinetics is included to advise on approaches necessary to minimize NO formation in external combustion systems while maintaining high efficiency and low CO and unburned hydrocarbons. 相似文献
914.
Richard H. Groth David J. Robertson 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1137-1140
Hydrocarbon emissions from gas turbine engines can be divided into unreactive and reactive components. The unreactive component consists of paraffins which do not take part in smog producing reactions with NOx. The reactive portion includes olefins, aro-matics and oxygenated derivatives of hydrocarbons which take part in smog producing reactions with NOx. Odor is attributed normally to the aromatics and oxygenates. Previous work led to the development of a high temperature subtractive analyzer (APCA 22, 696 (1972) which separates hydrocarbon emissions into a) paraffins and b) aromatics, olefins, and oxygenates. Liquid chromatographic techniques have also been used to separate the hydrocarbons into a) aliphatics, b) aromatics, and c) oxygenates. These aliphatics include olefins. In this work, engine emissions have been analyzed by these two techniques as a function of engine type, engine thrust (power) and fuel type. Specific engines tested were JT4, JT3D and JT9D. Fuels studied were JP5, and Jet A fuel. Power settings ranged from sub idle to high power. Results using the high temperature subtractive analyzer indicate that the % unreactive hydrocarbons ranges from 30 % at idle to near zero at high power for these engine types and fuels. In general, the higher the total hydrocarbon level, the higher the % unreactive hydrocarbons. Total hydrocarbons decrease sharply with increase in thrust. The emissions from different types of engines at various power settings were collected on an adsorbent Chromosorb 102 and the adsorbate analyzed by liquid chromatographic techniques at A. D. Little, Inc. These results showed similar trends from low power to high power. The oxygenate fraction increased and aliphatic portion decreased. However, the data for this portion of the work were very limited and no firm conclusions can be drawn. 相似文献
915.
Richard P. Bundy 《Journal of the Air & Waste Management Association (1995)》2013,63(7):754-758
Operation and maintenance and performing correct system monitoring of fabric filters is discussed. The anticipation of future problems at the time of start-up and the necessity of maintaining correct records on the system to assist in later troubleshooting is stressed. When all is going well, the fabric filter requires little but routine maintenance on moving parts, which is usually well identified in the service manuals. Problems usually appear as excessive emissions, high pressure drop, or inadequate bag life. In order to find the cause of these problems, one must have maintained sufficient Information on the system to identify what changed and when. With this information, there are logical paths to follow to the proper solutions. 相似文献
916.
William D. Vernon Bert M. Wyman Richard V. Hubert Joseph R. Snyder 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1280-1282
A manual method for measuring reduced sulfur compounds in kraft pulp mill and sulfur recovery plant emissions was evaluated. The method involves removing SO2 from the gas stream (if present) with a citric acid-potassium citrate buffer that passes reduced sulfur compounds; thermal oxidation of all reduced sulfur compounds to SO2; collection of the SO2 in H2O2; and a titrimetric analysis of the H2O2 for SO4 2?. A heated filter removes alkaline particulate matter that would produce a negative interference if absorbed by the buffer. When used at kraft pulp mills, the method agrees closely with Reference Method 16, provided that nonregulated reduced sulfur compounds, such as carbonyl sulfide, are not present in the emissions. At sulfur recovery plants, nonregulated reduced sulfur compounds, such as thiophene, are likely to be present in the emissions and will produce a positive bias in the results obtained with this method. The precision of the method ranges from 1 to 7 percent relative standard deviation. 相似文献
917.
Peter A. Gabele James O. Baugh Frank Black Richard Snow 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1168-1175
Exhaust and evaporative emissions were examined from vehicles fueled with methanol or a gasoline-methanol blend. Regulated automobile pollutants, as well as detailed hydrocarbons, methanol, and aldehydes were measured, and exhaust emission trends were obtained for vehicle operation over five different driving cycles. Results indicated that use of the blended fuel does not generally have any significant effect on base-line exhaust emission rates of regulated pollutants; however, emission rates of aldehydes increased during the Federal Test Procedure. Aldehyde emissions from the methanol-fueled car were roughly an order of magnitude higher than those resulting from blended fuel usage. The hydrocarbon composition of evaporative emissions with the blended fuel was similar to that with the base-line fuel except when canister breakthrough occurred. Evaporative emissions during breakthrough were comprised chiefly of N-butane. 相似文献
918.
919.
Barry Dellinger Sue L. Mazer Richard A. Dobbs 《Journal of the Air & Waste Management Association (1995)》2013,63(6):838-843
Laboratory thermal decomposition studies were performed to evaluate potential emissions from sewage sludge incinerators. Precisely controlled thermal decomposition experiments were conducted on sludge spiked with mixtures of hazardous organic compounds, on mixtures of pure compounds without sludge, and on unspiked sludge. Experiments were conducted in nitrogen and air atmospheres with gas phase reaction times of 2.0 seconds over the temperature range 300°C-1000°C. It was found that sludge inhibited the decomposition of moderately stable spiked contaminants but accelerated the decomposition of the most stable components. This effect was attributed to radical scavengers produced by the sludge matrix at lower temperatures which then decomposed at higher temperatures. A multiple hearth simulation study suggested that most of the organic material present In the sludge matrix is vaporized within the upper hearths that are held at lower temperatures and may consequently escape from such incinerators undestroyed. A number of stable byproducts resulted from the sludge decomposition that may be of environmental concern. 相似文献
920.
Richard T. Enander Victor A. Bell 《Journal of the Air & Waste Management Association (1995)》2013,63(4):510-512
A comparative analysis of forest precipitation depositions was performed using pine tree barks as biomonitoring tools and throughfall collectors in pine stands at various test sites in eastern Germany. For the elements sulfate sulfur (SO4-S), nitrate nitrogen (NO3-N), ammonium nitrogen (NH4-N), calcium (Ca), and iron (Fe), regression equations with r2 values between 0.81 and 0.96 were derived, enabling yearly conversion of bark loads to throughfall rates (TFRs) in pine stands (g*m-2*year-1). Applying this method to a network of 53 measuring sites in Dübener Heide nature park, north of Leipzig, lead to discovering spatial patterns of TFRs for SO4-S, NO3-N, and NH4-N in 1994. Differences between the TFRs of sulfur and nitrogen were traced back to different emission sources and the temporal trend related to major infrastructural changes in that region since 1990. Results suggest that the bark method will be particularly suited to identifying forest precipitation depositions of ecotoxicologically relevant airborne pollutants on regional scales. 相似文献