![]() Sulfur oxides (SOx), mainly SO 2, are of concern due their potential to create sulfuric acids. The main reactions occurring in catalytic NOx treatment are as follows:ĢNO 2 + 4NH 3 + O 2 ➝ 3N 2 + 6H 2O (slow) Catalysts typically consist of TiO 2, V 2O 5 or WO 3. The ammonia-based gas thus created then reacts with the NOx over a catalyst. In order to avoid the risk of undesired formation of ammonium sulfate (AS) or ammonium bisulfate (ABS) at lower temperatures, the inlet temperature must be controlled to remain above 662☏. In applications with high-temperature furnace offgas (around 1,150☏), water spray injection, fresh air dilution or heat exchangers can be used to cool and control the gas velocity and temperature distribution in order to reach the optimum reaction conditions. The NOx-reduction operation is performed by injecting an ammonia-based reagent. Catalytic reduction of NOx is typically performed at a temperature range between 600 and 700☏. Common technologies used to remove NOx are selective catalytic reduction (SCR), which reacts NOx with ammonia at around 700☏ with the aid of a catalyst, and selective non-catalytic reduction (SNCR), which reacts with ammonia at even higher temperatures to reduce NOx emissions. Oxides of nitrogen (NOx) include nitrogen dioxide and nitric oxide. These methods are described in the following sections. To understand the process specifics for CCF systems, it is first important to outline the traditional treatment technologies for the major air pollutants: NOx, SOx and PM. A CCF system can simultaneously remove multiple pollutants, including SOx, NOx, particulate matter and dioxins Tackling air pollution Glass industry furnaces (float glass, tableware and container)įIGURE 2.CCF systems have seen successful installations in many industrial applications, including the following: Figure 2 summarizes the removal efficiencies of a CCF unit for various pollutants. Such catalyst ceramic filtration (CCF) installations can achieve simultaneous pollutant removal with lower capital expenditure and plot-space requirements than traditional baghouse or ESP configurations. Simultaneous removal of the three major pollutants from fluegas can also be achieved with catalyst-impregnated ceramic filter elements within one housing-boxed system (Figure 1). Currently, industrial pollution-control equipment installations are dominated by baghouse fabric filters and electrostatic precipitators (ESPs).
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