Air Pollution Its Origin and Control Second Edition [Kenneth Wark and Cecil F. Warner] on echecs16.info *FREE* shipping on qualifying offers. Classic text about . Air Pollution: Its Origin and Control, 3rd Edition. Kenneth Wark, both of Purdue University. Cecil F. Warner, both of Purdue University. Wayne T. Davis, University . The authors continue to expose students to both the quantitative and the qualitative aspects of air quality management and air pollution control with several new.
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Air pollution: its origin and control by Kenneth Wark. Air pollution: its origin and control. by Kenneth Wark; Cecil Francis Warner; Wayne T Davis. Print book. Download Citation on ResearchGate | Air pollution: its origin and control | The first The second edition essentially continues to present information on the. The second edition essentially continues to present information on the Wark, K. , and Warner, C.F. Air pollution: its origin and control. United.
This mix is patted down into disc-shaped cakes, dried, and then used as fuel in stoves. When it burns, it produces smoke and numerous indoor air pollutants at concentrations 5 times higher than coal. Fuel and biomass burning[ edit ] A rural aburo stove using biomass cakes, fuelwood and trash as cooking fuel. Surveys suggest over million households in India use such stoves chullahs every day, 2—3 times a day. Clean burning fuels and electricity are unavailable in rural parts and small towns of India because of poor rural highways and limited energy generation infrastructure. Fuel wood and biomass burning is the primary reason for near-permanent haze and smoke observed above rural and urban India, and in satellite pictures of the country.
Series The IEP series in mechanical engineering. Classifications Dewey Decimal Class The Physical Object Pagination xvi, p. Number of pages Check nearby libraries with: WorldCat Library. download this book site. Share this book Facebook.
History Created April 1, 5 revisions Download catalog record: Wikipedia citation Close. Edit Last edited anonymously November 27, History 1 edition of Air pollution, its origin and control found in the catalog.
November 27, GOV collections: Book Not Available Representatives from industry and environmental groups as well as government and state officials offered testimony at a hearing on H. These bills would control air pollution from sources on the outer continental shelf and would reduce the harmful effects of air pollution associated with ozone and carbon monoxide concentrations. In addition, this legislation would insure the safety of consumers in issuing regulations concerning mobile sources.
The main focus was on bill H. It reviews available technologies for controlling sulphur emissions; and conducts a cost-benefit analysis of alternative programs for sulphur emission control in the ECE region. Part One documents the effects of sulphur compounds on aquatic ecosystems; soil, groundwater, and vegetation; various materials, including historical and cultural monuments; visibility; and personal health. Part Two examines technologies for reducing the sulphur content of fuels, modifying combustion gases, utilizing recovered materials, and disposing waste products from desulphurization technologies.
The California Energy Commission is mandated by the Warren-Alquist Act to maintain adequate and reliable supplies of electricity, and to protect environmental quality standards. The five major mechanisms which result in de-activation of a catalytic converter bed are: Sintering is the loss of active surface area of the adsorbent, i. Sintering occurs due to agglomeration of small metal crystallites into larger ones.
At high temperatures, extreme sintering leads to the transformation of the catalytic crystalline phase of the metal into a non-catalytic one. This phenomena is called solid- state transformation Forzatti et al.
Large pressure drop across the catalyst bed is a result of fouling Bartholomew, As discussed in an earlier section, the use of TEL was done as a fuel additive in the s. TEL in the gasoline decomposed in the cylinders and formed a mixture of halides and oxides.
A part of this mixture was emitted as gases and remaining left as particulate matter ranging in diameter from 0. This blocked the pores of the honeycomb structure in the catalytic converter and thus resulted in reduced efficiency Wei, An example of fouling in a catalytic converter is shown in Figure 5.
Figure 5. Fouling of a Catalytic Converter Eastern Catalytic, 5. Very high velocity of exhaust gas can also result in erosion of the catalyst bed.
Bartholomew, An example of poisoning in a catalyst bed is shown in figure 5. P could be present in the form of impurities in the fuel and also in engine lubricants. A layer forms on the wash-coat surface, comprising of Zn, Ca and Mg phosphates. This occurs due to the dissociation of SO2 into oxygen and free sulfur; the latter gets strongly adsorbed onto the precious metal sorption site, thus blocking the site from interacting with NOx, CO and UHCs Degobert, While the presence of Si in the fuel is very low, fugitive presences of soluble forms of Si in the fuel could occur, resulting in the formation of Si deposits on the catalyst bed.
Limitations and Disadvantages of Catalytic Converters Catalytic converters are a major means in controlling the emissions of NOx, UHCs and CO, three harmful products emitted by gasoline combustion engines. However, the use of catalytic converters is not the very ultimate solution to the control of these harmful emissions. There are several limitations and disadvantages of proliferating the use of catalytic converters in automobiles. This section deals with the negative aspects of using catalytic converters.
The catalyst bed must reach a temperature of OC to be effective Degobert, When an engine is started, the engine as well as the catalyst bed are at ambient temperatures. As the engine operates, it heats up and the hot exhaust gases emitted by the engine start heating up the catalyst bed. Due to inability of the catalyst to convert the emissions during light-off period, the emissions during this period are higher Amin et al.
These emissions are known as Cold-Start Emissions. Figure 6. The UHC emissions on the vertical axis are in cumulative form. It is evident from the graph that the highest proportion of the emissions occur during the first seconds of the cycle, which is the light-off period.
The cycle has two phases: These are precious metals and are thus expensive. As of November , the prices of the precious metals used as catalysts are as under: Table 6. Current Prices of Precious Metals on a 1 lb.
Rh mass ratio of the three noble metals to As can be seen in the table above, the cost of Pt is higher than both Rh and Pd. Because of the high cost of these noble metals, the overall price of a catalytic converter increases. The cost breakdown of the catalyst bed of a typical TWC is shown in Table 6. It is evident that the cost of impregnating the noble metals onto the surface of the substrate is more than that of the noble metals itself.
Platinum mining, for instance, has been proven to have negative effects on the aquatic ecosystems, water quality and sediment quality of the water bodies around the mining operation site Gumede, Platinum occurs in deposits with 5 other elements: Tailings are the non-metallic materials and often contain undesired toxic metals such as cadmium, lead, and arsenic present in the ores of PGMs. The mining and extraction process generates large amount of tailings ELAW, One of the limitations of catalytic converters are that though they are converting the harmful NOx gases to the inert and harmless N2 gas, they are simply converting the UHCs and CO, two harmful gases, to CO2, a relatively less harmful gas.
However, the increased CO2 emissions are certainly not desirable. With increase in concentration of CO2 in the atmosphere, there are several ill effects that may occur, such as increased acidity of natural water bodies and increased melting of polar ice caps due to global warming, causing a rise in the mean sea level Soon et al. Recent Developments in Catalytic Converters It has been established in the Section 6 that though catalytic converters are effective in controlling the harmful emissions from automobiles, they have certain limitations such as light- off and high capital costs.
There have been several recent developments in the field of catalytic converters in order to mitigate these limitations. Some of these developments have been discussed in this section. A clear solution to this limitation would be to employ a heat source that can heat up the catalyst bed rapidly after cold start and thus effectively eliminate light-off period. However, a large amount of energy is needed for heating the catalyst bed to such a high temperature.
The TWC could be moved closer to the engine itself, so as to attain rapid heating of the bed due by convection from the engine.
But this could result in overheating of the catalyst bed and cause thermal degradation of the precious catalysts used.
Past approaches to solving the issue of cold-start emissions have included electric heating of the catalyst. This approach requires a large energy input of 2kW and reduces the light-off period to 30 seconds. But by this approach, cold- start emissions are only reduced, not eliminated. Moreover, electrically heating the catalyst causes physical stress that causes distortion of shape and deactivation of the catalyst bed Adams et al.
The technology is based on the principle that hydrogen gas has a very high thermal conductivity even at low pressures. The high thermal conductivity of hydrogen gas is evident from the data in Table 7.
An insulation jacket is placed around the TWC with metal hydride typically zirconium hydride coated on the cooler side, as shown in Figure 7. The metal hydride is electrically heated. As the temperature is increased, the metal hydride undergoes thermal oxidation and releases hydrogen gas. H2 absorbs the heat, expands and settles exothermally on the other end of the jacket, which is adjacent to the TWC.
Thus, the TWC is heated and light-off period is shortened. Once the light- off period is over, the electrical heating is stopped and H2 gas is reduced back to hydride form, thereby reducing the conductance Benson et al. By using VCI, energy saving is also achieved: As the engine is started again, the stored heat is utilized to heat up the TWC Adams et al. Figure 7. Table 7. VCI can maintain this temperature for up to 10 hr Adams et al. However, when engines are started after longer periods of rest, the heat stored by the VCI is lost.
Moreover, no additional energy input is required to heat the converter because the energy of the exhaust gases from previous run of the engine is stored for subsequent uses. PCMs typically used in TWCs are metal alloys and eutectic salt mixtures because of their high heat of solidification and melting Korin et al.
When engine is turned off, PCM starts undergoing partial solidification and the latent heat released keeps the TWC hot for a long duration Bokde et al. A typical TMS converter is shown in Figure 7. But due to an extremely high temperature of OC, the PCM was very difficult to melt during the test cycle.
Yet, after 23 hr of turned-off engine, the converter was at OC. Moreover, alternating layers of Cu foil and glass were used to provide radiation shielding within the VCI. A comparison of converter cool-down time periods for different technologies NREL, 7. Hence, it is essential to derive maximum use out of these metals till they are exhausted completely. Poisoning of the catalyst bed of a TWC by phosphorus was described in the earlier section as: Reactivation of these catalysts can be carried out by several methods.
One such method is the use of EDTA ethylene diamine tetraacetic acid. EDTA is a strong chelating agent. The effectiveness of reactivation by these chemicals was tested by Christou et al. The results of reactivation obtained are shown in the Figure 7. Summary and Conclusions Today, air pollution is one of the major environmental concerns on a global scale. The modern catalytic converter has been modified and evolved with the employment of variable-conductance insulation, phase-change material and thermal management systems.
CO2 may be relatively less harmful than its precursors in catalytic conversion, but it not a harmless gas. Emphasis may be placed on improving the design of the engine and purity of gasoline, such that the amount of pollutants generated are reduced in the first place.
Moreover, reduced generation of pollutants implies that the TWC has to treat a smaller volume of gases.
Thus, longer life of the catalyst bed is achieved. It is crucial to carry out sustainable practice when it comes to fuel use and emissions.
Awareness has to be created among people regarding the impact of their day-to-day driving on emissions and the impacts of these emissions on a global scale. References Adams, D. Amin, M. Bartholomew, C. General, vol. Benjamin, M. Water Chemistry. McGraw-Hill, c Benson, D. Birgersson, H. PhD Diss.
Bleiwas, D. Geological Survey Open-File Report —, pp. Blumenthal, D. Anatomy of a Los Angeles Smog Episode: