Emissions control from stationary sources

The East Bridgewater facility (also serving Brockton), was built with an incinerator, (conventional except that it has bag filters for emission control), and as an alternate disposal means, a Resource Recovery facility. In 1972 CEA entered into an agreement with Arthur D. Little (ADL) to develop processes for emission controls from stationary sources and also for treatment of Municipal Solid Wastes. 

Control of stationary sources of air pollution requires the application of either the control concepts mentioned in Chapter 28 of the control devices mentioned in Chapter 29. In some cases, more than one system or device must be used to achieve satisfactory control. The three general methods of control are (1) process change to a less polluting process or to a lowered emission from the existing process through modification of the operation,... 

EPA, 1982. U.S. EPA, Office of Air Quality Planning and Standards, "Control Techniques for Particulate Emissions from Stationary Sources, Volume 1," EPA-450/3-81-005a, Research Triangle Park, NC, September, 1982. 

Control Technologies for Sulfur Oxide Emission from Stationary Sources," 2" Edition, Research Triangle Park, NC, April, 1981. 

Emission control from heavy duty diesel engines in vehicles and stationary sources involves the use of ammonium to selectively reduce N O, from the exhaust gas. This NO removal system is called selective catalytic reduction by ammonium (NH3-SGR) and it is additionally used for the catalytic oxidation of GO and HGs.The ammonia primarily reacts in the SGR catalytic converter with NO2 to form nitrogen and water. Excess ammonia is converted to nitrogen and water on reaction with residual oxygen. As ammonia is a toxic substance, the actual reducing agent used in motor vehicle applications is urea. Urea is manufactured commercially and is both ground water compatible and chemically stable under ambient conditions [46]. 

The control of NO from stationary sources includes techniques of modification of the combustion stage (primary measures) and treatment of the effluent gases (secondary measures). The use oflow-temperature NO,.burners, over fire air (OFA), fiue gas recirculation, fuel reburning, staged combustion and water or steam injection are examples of primary measures they are preliminarily attempted, extensively applied and guarantee NO reduction levels of the order of 50% and more. However, they typically do not fit the most stringent emission standards so that secondary measures or flue gas treatment methods must also be applied. 

Although the standard urea-ammonia SCR technology is nowadays well established and used world-wide for the control of NO, from stationary sources, additional applications are predicted in large gas turbines, incinerators, stationary diesel engines and the cement and glass industries in view of the enforcement of stricter emission limits and of the high cost of alternative very efficient primary methods. 

Control of sulfur dioxide emissions from stationary sources (such as power plants) usually takes one of three forms fuel cleaning, also known as fuel beneficiation removal of sulfur during combustion or flue gas processing. 

Reduction of Nitric Oxide with Ammonia. - Control of the emission of NO from stationary sources is possible by selective catalytic reduction, for which up to now NH3 is the only effective reductant in the presence of excess 02. Beside noble metal catalysts Bauerle etal.101 109 and Wu and Nobe108 studied Al2 03-supported vanadium oxide and found this to be highly effective in NO removal which is considerably enhanced by the presence of 02. Alkali metal compounds which are usually added as promoters for S02 oxidation completely inactivate the catalysts for NO reduction. Adsorption kinetic studies indicated first-order dependence on NH3 adsorption. Similar results were obtained for NO on reduced vanadium oxide, but its adsorption on... 

The American 1970 Clean Air Act defined ambient air quality standards (NAAQS) in the United States for atmospheric ozone, NO, lead, carbon monoxide, sulfur oxides, and PM-10 (particulate matter less than 10 p.m). The strategy to reduce levels of lead, NOx, PM-10, and to some extent carbon monoxide was to control emissions from automobiles that included the phasing-out of leaded fuel. As previously noted, ozone is a product of the photochemical reaction of volatile organic compounds with NOx (photochemical smog), so the balance between organic compounds and NOx pollutants is important in meeting target ozone levels (e.g., 0.12 ppm). Emissions from stationary sources is an important factor, and limits have been set for them. Because of low pressure drop requirements, coated monolithic catalysts... 

Stationary sources are the major contributors of most environmentally important metals in air. Flinn and Reimers (23) reported the annual airborne emissions of metals in the United States from stationary sources projected through 1983 based on production estimates and assuming no changes in processes or control technology. Their results, summarized in Table V, show projected increases in emissions from all environmentally important metals where data are available. Comparatively low concentrations (150-900 ton/year) of the highly toxic metals— berylhum, selenium, and mercury— were reported for the 1969-1971 period. Metals emitted in the highest concentrations are zinc (151,000 ton/year) and titanium (88,000 ton/year), although iron could be expected to exceed these levels. 

Control Techniques for Nitrogen Oxide Emissions from Stationary Sources, ... 

The Environmental Agency of Japan has conducted questionnaire surveys on the emission of air pollutants from stationary sources every three years, in order to obtain information for promotion of air pollution control policy. Based on the results of these surveys, together with the data on emission factors for mobile and other sources, the emission trends for SO2 and NO are shown in Table 5. 

Catalyst monoliths are also effective in the control of air pollution from stationary sources. They have been used for many years to oxidize hydrocarbon vapors in the vent streams from chemical plants and to reduce solvent emissions from printing and cleaning processes. More recent applications include CO removal from gas turbine exhaust and the selective catalytic reduction of NO in flue gas. Performance curves for the oxidation of various compounds over a Pt/Al203 catalyst are shown in Figure 10.5, where the conversion is plotted against the feed temperature. The reactors operate adiabatically, and the exit temperature may be 10-100°F above the feed temperature. At first, the conversion increases exponentially with temperature, as expected from the Arrhenius relationship. The decrease in slope... 

Schuetzle, D Prater, T. J., Ruddell, S. R. Sampling and Analysis of Emissions from Stationary Sources, 1. Odor and Total Hydrocarbons, J. Air Pollut. Control Assoc. 25, 925(1975)... 

Over the last two decades, emphasis was placed on reducing VOC emissions in order to attain the ozone ambient air quality standard. The 1970 and 1977 amendments to the CAA did not explicitly require NO, reductions from stationary sources for purposes of attainment of the ozone standard. The best available scientific evidence at the time suggested that VOC reductions were preferred in most instances. The VOC control approach was reinforced by the fact that NOx reductions could in some cases increase ozone concentrations. 

Industrial plants have been relying on a form of SCR since the 1960s [19], however, the controlled and stable nature of industrial plant operation allows several degrees of freedom that are not possible on a vehicle. Industrial plants have relatively steady emissions output, are able to introduce gaseous NH3, can control the temperature of the catalyst to a very narrow window, and readily employ cleanup catalysts as the space constraints are not as limiting as on a vehicle. With these factors in mind, the low-cost vanadium and tungsten oxides supported on titania are the most widely used catalysts employed to selectively reduce NOx from stationary sources [20]. These catalysts have also been implemented for diesel vehicles in Europe, but they have limited thermal durability as well as the potential to emit harmful gaseous vanadium [21-23]. 

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