Smoke stack

One way to remove nitrogen oxide (NO) from smoke stack emissions is to react it with ammonia. 

FB boilers are similar to SM boiler designs except that, instead of a fully immersed furnace tube, they have a bottom furnace (with a crowned combustion chamber) that sits on a refractory floor. Two-pass fire tubes (smoke tubes) connect the combustion chambers to the gas exit vent (smoke stack). 

It has been recognized for some time that fluids in motion, such as the atmosphere or the ocean, disperse added materials. This properly has been exploited by engineers in a variety of ways, such as the use of smoke stacks for boiler furnaces and ocean ontfalls for the release of treated wastewaters. It is now known that dilution is seldom the solution to an enviromnental problem the dispersed pollutants may accumulate to undesirable levels in certain niches in an ecosystem, be transformed by biological and photochemical processes to other pollntants, or have nnanticipated health or ecological effects even at highly dilute concentrations. It is therefore necessary to rmderstand the transport and transformation of chemicals in the natural environment and through the trophic chain ctrlminating in man. 

While the use of low-sulfur fuels is one mechanism to reduce sulfur dioxide emission, alternatively most approaches focus on scrubbing or ridding the emissions in smoke stacks of sulfur dioxide gas. A number of different types of scrubbers, i.e., sulfur dioxide removal systems, are available for industry. One system sprays the flue gas into a liquid solution of sodium hydroxide. The hydroxide combines with SO2 and O2 to form the corresponding sulfate which can be removed from the aqueous solution ... 

Polycyclic aromatic hydrocarbons (PAH) are widespread environmental contaminants and one of the most potent classes of carcinogenic chemicals. They are byproducts of combustion, and significant levels are produced in automobile exhaust, refuse burning, smoke stack effluents, and tobacco smoke. It is strongly suspected that PAH may play an important role in human cancer. 

Results small scale fire tests. Initially we had in mind to make a comparison between NT-FIRE 025 and NT-FIRE 004 "box test" since most lining materials had been classified using that method. It turned out that the gases generated by the method NT-FIRE 004 needed a very high dilution before they could be fed into our direct reading instruments. Instrumentation used for smoke stack sampling. EMP-797, turned out to be suitable for our purpose. 

When air pollutants exit the smoke stack or exhaust pipe (called the sources), they are advected by winds and dispersed by turbulent diffusion. Winds blow from high pressure toward low pressure cells at speeds that depend on the pressure gradient. Because of the Coriolis force, wind trajectories are curvilinear in reference to fixed Earth coordinates, although within a relatively short (few to tens of km) distance, wind trajectories can be approximated as linear. Winds have a horizontal and vertical component. Over flat terrain the horizontal component predominates in mountainous and urban areas with tall buildings, the vertical component can be significant, as well at the land/sea interface. 

Fig. 4. Balti power plant run by AS Narva Elektrijamaad with ash plateaux and pond with ultra-alkaline leachate in foreground. The two tallest smoke-stacks are 180 m (Photo Courtesy AS Narva Elektrijamaad, from www.powerplant.ee/eng/photos.php).

Pulverized oil shale is the main fuel for Estonian power stations, and atmospheric emissions therefrom have been studied in detail by Aunela et al. (1995), Hasanen et al. (1997), and Jalkanen (2000). The main emissions are acidic or greenhouse gases (SO2, NOx, CO2) and large amounts of airborne particulate matter that escape the trapping devices in the smoke stack (i.e., the part of fly ash <50 xm in diameter). 

Some degree of fractionation as function of distance from the power station smoke stack is to be expected coarse particles will fall out in the immediate vicinity of the power station, whereas fine fly ash will be transported further, and gaseous emissions might be expected to be transported the furthest. Thus, from the point of view of environmental health, not only the chemical composition of emitted particles and aerosols, but also their size, is relevant (Teinemaa et al. 2002). As particulate matter is dominated by basic oxides (e.g., CaO) and gaseous emissions by acidic gases (e.g., CO2, SO2), this fractionation will influence the pH of... 

Monitoring the effluent of a smoke stack, or the concentration of a drug in a patient requires that the sampling rate is as low as possible and that can be predicted with a known probability that between the sampling times no fatal concentration change will occur. If it is expected that the monitored value will exceed a preset value a simple action can prevent that administer some drug, open or close a value, etc. 

Historical. The gases from a blast furnace, the smoke-stacks from boiler furnaces, cement plants, etc carry with.them solid particles in the form of dust. While the greater part of this dust may be recovered by passing the gases thru a dust collector , such as shown in Fig 242 of Ref 3, p 720 (our Fig E27) there are dusts, however, too fine to settle in the collector. The dust collector provides a... 

Emission measurement techniques have in many applications proven very useful in providing an alternative to the absorption method. Emission measurements free the experimenter from the time and position restraints imposed by a celestial source and remove the complications imposed by the necessity to position a remote source in line with the gas sample of interest. One example of the application of emission measurements and their effectiveness, is their use to measure the effluents from sources such as smoke stacks (57). In this application there is usually a temperature differential which allows discrimination between the target and the ambient atmosphere. This type of measurement is most effective in monitoring target gases when they are in close proximity to the source since the target gas temperature soon becomes the same as the ambient atmosphere and their measurement becomes much more difficult if not impossible. 

Transport mechanisms include mass movement of soil (soil erosion and landslides), wind, rain, surface waters (rivers and lakes), groundwater, and human intervention. The latter may consist of wastewater pipes, drainage ditches, roads, trains, ships, smoke stacks, etc. 

Finally, in an established application, silver membranes have also been utilized to capture coal-tar pitch volatiles and fly ash directly from smoke stacks and used in subsequent analysis [Minneci and Paulson. 1988]. 

This instrument has been available commercially for a few years (Lear Siegler Model SM400) and offers strong potential for monitoring the lower-boiling PNA and other simple aromatic molecules. Thus far it has been sold primarily for the in situ monitoring of NOx and SO2 inside smoke stacks. Its attractiveness for us is in its ability to provide rapid analysis of synfuel pollutants. 

Coal generally contains a mineral fraction that amounts to 5-20 wt.%. During combustion, most of the minerals are transformed into dust-sized, glassy particles and, along with some unaltered mineral grains and unburned carbon, are emitted from the smoke stacks. These particles contribute to the smog problem, are eye- and respiratory irritants, and act as substrates for the deposition of sulfuric and nitric acid. 

We consider the case of an aerosol illuminated by a collimated light source of a given wavelength. The experimental arrangement is shown schematically in Fig, 5.6. A photometer of this type installed in a smoke stack or duct would be suitable for measuring the attenuation... 

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