Flue Gases from Stationary Sources

Abstract

The sections in this article are Emissions from Stationary Sources Drivers for Flue Gas Cleaning Technology The USA E urope A sia C hina J apan NO x Removal Technologies Nitrous Oxide (N 2 O) Selective Catalytic Reduction ( SCR ) SCR Technology SCR Catalysts Different Catalyst Types Choice of Carrier Optimization of Activity The Effect of Increasing V 2 O 5 Loading Activation Energy as a Function of Vanadium Content The Effect of Co‐Oxides SCR Reaction Mechanism for Vanadium Catalysts: the Eley–Rideal Route Global Kinetics The Importance of B rønsted Acidity The Influence of Reoxidation or NO 2 The Influence of Gas Composition on Reaction Rate The Influence of Water The Influence of O 2 Modeling Definition of Different Model Types Estimation of Interphase Mass Transfer Intraporous Mass Transfer Kinetic Expressions The Feasibility of Different Models Deactivation Chemical Poisoning Surface Fouling, Pore and Channel Clogging Sintering Catalyst Management and Regeneration SCR Catalyst Testing Laboratory‐ and Bench‐Scale Testing Pilot‐Scale Testing Slip‐Stream Reactors Full‐Scale Catalyst Testing Gas Sampling and Analysis Other Emissions Sulfur Removal The Wet Sulfuric Acid ( WSA ) Process and Combined WSA and De NO x ( SNOX ) Hydrogen Sulfide Carbon Monoxide Carbon Dioxide Hydrocarbons Dioxins Hg Oxidation and Capture Hg Oxidation Thermodynamics Hg Removal from Coal‐Fired Power Plants A Conventional Flue Gas Cleaning Processes B Sorbent Injection, Coal Additives, and Coal Blending Hg Oxidation Mechanism and Catalysis Alternative Processes Multipollutant Processes The DESONOX Process Other Combined Processes Catalytic Filters New Technologies Plasma‐Assisted Processes Photocatalytic Processes

Structure of Isolated Vanadia and Titania: A Deep UV Raman, UV–Vis, and IR Spectroscopic Study

“…Titania is also commonly used as a catalyst support material for noble metals and oxides as it induces a strong interaction with the active phase . For example, titania-supported vanadium oxide catalysts have been widely used as catalysts for selective oxidation reactions of organic compounds and the selective catalytic reduction (SCR) of NO x with ammonia . To this end, the use of silica as additional support may be beneficial because of its higher surface area and higher resistance to sintering.…”

Selective Catalytic Reduction of NOx over V2O5-WO3-TiO2 SCR Catalysts—A Study at Elevated Pressure for Maritime Pre-turbine SCR Configuration

“…Formation of other byproducts such as N2O from NH3 oxidation was not observed at any conditions. At atmospheric pressure water is known to limit the formation of N2O across V-SCR due to competitive adsorption [7,24], which also seems to apply for increased pressure. Fig.…”

“…3b shows that when NH3 becomes the limiting reactant at high temperatures the conversion of NOx levels off at a NOx conversion close to the ANR value, as also typically reported for atmospheric pressures. The fact that the SCR reaction is not affected by the increased pressure also means that a regular kinetic expression [15,24,42,43] taking into account the NH3 surface coverage can be used, either in more complicated forms of Temkin isotherms as discussed later or using regular…”

“…10. starts to become influenced by external and internal diffusion limitations and as the temperature is increased these limitations becomes more pronounced [24]. The increased diffusion limitations at increased pressure is linked to the inverse proportionality between pressure and the binary diffusion coefficient which will limit the SCR reaction.…”

“…SCR of NOx was first introduced in the 1970's and 1980's for the removal of NOx from stationary applications such as power plants, waste incinerators and within the chemical industry [15,22,23]. NOx is typically reduced over a catalyst containing 1-5 wt% V2O5/~10 wt% WO3/TiO2 (V-SCR catalyst) using an N-containing reductant such as ammonia (NH3) on stationary units or urea on mobile units, which decomposes into NH3 upon heating [15,16,24,25]. The SCR of NOx typically proceeds at temperatures between 200-500°C, during which NO is reduced according to Reaction (1) into harmless nitrogen and water.…”