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721.
Hans T. Karlsson Harvey S. Rosenberg 《Journal of the Air & Waste Management Association (1995)》2013,63(7):822-826
This is the conclusion of a 2-part article dealing with the technical aspects of lime/limestone scrubbers for coal-fired power plants, it covers instrumentation, participate removal and sludge disposal. Part I (June JAPCA) covered process chemistry and scrubber systems 相似文献
722.
723.
The requirements of environmental regulations imposed on industry are complex and expensive. As these regulations have developed, corporate compliance programs have had to become more sophisticated. For many, this means that an environmental auditing program is now timely (or overdue) for organizing their approach to meeting the constraints of these regulations. Contributing to this timeliness is a renewed emphasis by regulators on enforcement activities. This paper discusses what environmental auditing is and what it consists of, gives examples from a few approaches which are currently being used, and reviews some of its benefits and liabilities. 相似文献
724.
David W. Layfon Richard T. Cederwall 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1185-1190
The development of sour-gas resources in Canada and the United States has prompted concerns about the public health risks of accidental releases of gas contaminated with hydrogen sulfide (H2S) from wells. This paper focuses on methods for improving the prediction and management of those risks. Data associated with the health effects of hydrogen sulfide are examined, and it is suggested that sublethal effects should be addressed in risk assessments of sour-gas wells along with the life-threatening effects normally considered. The demarcation of hazard zones around wells can be improved by using a statistical approach for estimating an upper-bound H2S release rate; this rate can then be used in an atmospheric dispersion model to estimate maximum distances to downwind concentrations for lethal (300 ppmv) and sublethal (50 ppmv) effects resulting from an accidental release. A vertical release is found to have little impact, especially under stable atmospheric conditions; horizontal releases, on the other hand, result in the greatest downwind distances for health impacts. Management of health risks depends on a mix of safety technologies and contingency actions, such as well-ignition options and provision for post-release monitoring and assessment of ambient H2S concentrations. 相似文献
725.
Josephine A. Jackson Jude T. Sommerfeld 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1328-1243
The DSS/2 software system was used to numerically simulate oxygen stratification effects in a typical industrial boiler stack. The model developed for the simulation involves turbulent mass transfer in a tube with a constant, high mass flux from the walls of the tube. The concentration profile is considered to be developing, but the velocity profile is assumed to be fully developed. The model is for a gaseous system at constant temperature and pressure; the transport properties are shown to be constant. The universal velocity profile for turbulent flow and von Karman’s expressions for the turbulent eddy diffusivity are incorporated in the model. An expression for a wall concentration profile corresponding to conditions of high mass flux at the wall is developed. The model is then expressed as a system of partial differential equations which are solved using the numerical method of lines together with the DSS/2 numerical integration system. The resulting concentration profiles are presented for various flux rates which might be encountered in a typical stack. These profiles indicate that a potential for oxygen stratification in stacks does exist; they also suggest that careful placement of the oxygen cell probe can help minimize such errors. 相似文献
726.
R. K. M. Jayanty J. A. Sokash G. B. Howe R. G. Fuerst T. J. Logan M. R. Midgett 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1342-1346
A simple, inexpensive, and accurate technique for evaluating or auditing the sampling, recovery, and analytical phases of EPA Source Reference Method 25 has been developed. The technique involves spiking a U-shaped stainless steel cartridge containing Tenax® with known quantities of selected organic compounds and thermally desorbing them at temperatures from 160°C to 180°C to generate organic vapors quantitatively. The major advantages of this technique are that no other measurement methods can be used to determine the generated organic concentrations in lieu of Method 25; and that the cartridge can easily be taken to the field for evaluation. The organic compounds generated in test runs are collected and analyzed using the Method 25 procedure. The generation of organics is quantitative and recoveries were found to be 100 ± 10%. The time required for desorption of the majority of organics is generally less than forty-five minutes at a flow rate of 100 mL/min; however, based on laboratory experience the recommended sampling time is sixty minutes. These spiked cartridges are stable at room temperature over a two-month period. Results of interlaboratory studies showed close agreement with the expected concentrations based on calculations from the mass loadings and sample volumes. 相似文献
727.
728.
T. Tirabassi M. Tagliazucca P. Zannetti 《Journal of the Air & Waste Management Association (1995)》2013,63(5):592-596
This paper presents a mixed methodology for the simulation of atmospheric disperson phenomena in which vertical diffusion is computed using an analytical solution of the K-theory equation, while horizontal diffusion is simulated by the Gaussian formula. This new formulation, while maintaining a simple analytical form for the concentration field, incorporates the effects of power-law vertical profiles of both wind speed and eddy diffusivity. The performance of this approach, which has been implemented into a full computer package (KAPPA-G), is evaluated by comparison with data from SF6 tracer experiments. 相似文献
729.
730.
Judith C. Chow John G. Watson Richard T. Egami Clifton A. Frazier Zhiqiang Lu Andrew Goodrich 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1134-1142
Street sweeping is often proposed as a means of reducing the emissions from paved roads. The objective of this study was to evaluate the effectiveness of street sweeping on ambient particulate matter concentrations and to determine the difference In source contributions to PM10 concentrations between street sweeping and non-street sweeping periods. Chemically-speciated measurements of PM10 and PM2.5 were taken in the commercial section of Reno, Nevada, for a one-month sampling period. The Chemical Mass Balance (CMB) model was applied to these data and an average of approximately 50 percent of the PM10 was apportioned to resuspended geological material. During half of the sampling period, streets In the vicinity of the sampling site were completely swept with a regenerative-air vacuum sweeper, while no sweeping was performed during the remainder of the experiment. Ratios of primary geological contributions divided by primary motor vehicle contributions to PM10 were compared between sweeping and non-sweeping periods using analysis of variance. This ratio of source contributions minimizes the effects of variations in traffic volume and meteorological dispersion. No significant differences in geological contributions to PM10 were detected as a result of regenerative-air vacuum street sweeping. 相似文献