PP 07 12 02 “Fixed-Bed Study of Elemental Mercury Removal from Flue Gas Using a SiO₂-TiO₂ Nanocomposite” by Ying Li, Patrick Murphy and Chang-Yu Wu, University of Florida, Gainesville, FL. 5 p.
A novel methodology using titanium oxide (TiO₂) nanoparticles as a photocatalyst has been recently developed to effectively remove Hg⁰. Under ultraviolet (UV) irradiation, hydroxyl (OH) radicals can be generated on the surface of TiO₂ and then oxidize Hg⁰ into mercury oxide (HgO), which is retained on the particle surface due to its low vapor pressure. The efficiency of Hg⁰ removal using SiO₂-TiO₂ nanocomposite was able to reach up to 99% at low relative humidity at room temperature. It should be noted that typical coal-fired flue gas consists of much higher concentration of water vapor and various minor gas components such as HCl, SO₂, and NO_x. It has been reported that these minor gases significantly impact Hg adsorption and/or oxidation by carbon and flyash. The goal of this research was to identify the effects of the flue gas components on the Hg removal by SiO₂-TiO₂ nanocomposite and to explore possible surface interaction mechanisms. Results from this study can help evaluate the potential of applying this novel material as an effective Hg control strategy for coal-fired power plants.
IP 589 MERCURY, IP 202 RESEARCH, S 2816/11 TITANIUM DIOXIDE, S 4911/23 UTILITY, COAL-FIRED

PP 07 12 03 “Kinetic Modeling of Enhanced Mercury Removal” by Bela K. Deshpande and Alvaro I. Martinez, Texas A&M University-Kingsville, Kingsville, TX. 10 p.
This study demonstrates the application of H₂O₂ as a source of OH radicals to accelerate the oxidation of Hg⁰, using kinetic modeling. The reaction mechanism of the mercury oxidation was from past research and the reaction pathways were established to analyze the effect of H₂O₂ addition. Preliminary results indicate that the conversion of Hg⁰ into Hg²⁺ increases with the addition of H₂O₂. The optimum temperature range for the oxidation was found to be 470-500°C. The preliminary analysis of the species production rates indicates that the supply OH radicals increase the formation of Cl₂, which accelerates the formation of HgCl₂ and enhances the oxidation process. The pathway OH → ClO → HgO was prominent in the formation of HgO. Also, the HO₂ radicals produced from H₂O₂ motivated the NO→ NO₂ conversion, leading to multi-pollutant control. This research aims to investigate into the enhanced oxidation of elemental mercury to increase its capture in wet scrubbers.
IP 352 OXIDATION, IP 202 RESEARCH, IP 589 MERCURY, IP 276 MODELING

PP 07 12 04 “Acid Dewpoint Measurement” by Stuart Harris, Land Instruments International, Dronfield, United Kingdom. Pollution Engineering, June 2007, 2 p.
Visible blue plume emissions have been an unforeseen side effect of the increase in wet scrubber additions to power plants (to reduce the emissions of SO₂), coupled with the addtion of SCR units (for NO_x removal), which also add SO₃ into the flue gas as a result of the SO₂ oxidation in the vanadia-based catalyst bed of the SCR. An increased level of SO₃ in the flue gas results from the combustion of fuel containing these additives, a problem which is even more prevalent in RFO-fired boilers due to the reactions between vanadium oxides, oxygen and SO₂. Measuring ADT can assist with the use of other emissions reduction technologies by providing a constant SO₃ monitoring system. It can be effectively utilized alongside SCR units to ensure that an excess amount of SO₃ is not being produced as a result of the catalyst, while simultaneously allowing plants to cut down the high costs involved in using too much of the expensive SO₂-reducing fuel additives. Flue gas ADT measurement also can be helpful in assuring that electrostatic precipitators are functioning at optimum efficiency. SO₃ is injected into the gas flow to reduce the resistance of the flyash and increase the electrostatic precipitator’s (ESP’s) ability to collect the particles effectively, yet if the ash becomes saturated with an excess of damaging SO₃, this excess is then released into the environment in the exit gas and may contribute to the formation of a blue plume. The SO₃ slip in the ESP can be monitored using sulfuric ACT measurements to ensure that the correct amount of SO₃ is being added during this process, an aid that will both optimize ash collection in the ESP and prevent damaging and regulated emissions of SO₃.
IP 530 FLYASH HANDLING, IP 593 ACID MIST, IP 591 FGD SYSTEMS, IP 576 SO₃, IP 272 MONITORING

PP 07 12 05 “Critical Review of Mercury Chemistry in Flue Gas” by M. H. Mendelsohn and C. D. Liverpood, Argonne National Laboratory, IL. NTIS DE2007-898529ABS, November 2006, 98 p.
This report begins by summarizing the survey process and describing how the results were used to shape the critical review. Analyses of information obtained from the various publications are presented chronologically, beginning with the earliest relevant publication found and concluding with the end of the review in early 2003. Finally, the conclusions and recommendations for future research are presented. The survey instrument is included in Appendix A, while detailed information on each of the publications reviewed is given in Appendix B.
IP 112 SURVEYS, IP 589 MERCURY

PP 07 12 06 “Efficiency vs Corrosion: Sulphuric Acid Dewpoint Monitors Find the Right Balance” by Stuart Harris, Land Instruments International, Dronfield, United Kingdom. Modern Power Systems, July 2007, 2 p.
Power plant operators need to steer a course between low flue gas temperatures that may cause H₂SO₄ deposition, with consequent corrosion, and high flue gas temperatures, which may avoid corrosion but increase heat losses and reduce efficiency. A sulphuric acid dewpoint monitor can provide continuous and clear guidance on what the optimal flue gas temperature should be. Another common corrosion issue arises from inefficient electrostatic precipitator (ESP) function. If the acid is allowed to come into contact with flyash, acid smut is formed which may then initiate corrosion in places where it settles. It is important to ensure that the ESP is working efficiently in order to remove this acid smut, thereby preventing its emission to the atmosphere or collecting in the stack and causing additional corrosion. In many ESPs SO₃ is injected into the gas stream to improve the efficiency of the ESP. An acid dewpoint monitor can be used to monitor for SO₃ slip caused by the injection of too much SO₃.
IP 205 EFFICIENCY, IP 610 CORROSION, IP 272 MONITORING, S 2819/02 SULFURIC ACID

PP 07 12 07 “Fly Away Fly Ash” by Jug A. Wollensky. Modern Power Systems, July 2007, 1 p.
Current obsession with so-called carbon emissions has diverted opprobrium from old-fashioned acid rain. Only a few decades ago this pollutant made coal-fired power stations into hate targets almost as good as nuclear ones. The fly ash from coal-firing of course contains rain-acidifying sulphur and nitrogen oxides; and electrostatic precipitators are among the well-known countermeasures. Unfortunately fly ash particles tend to accumulate on precipitator plates, and so much so that big hammers may be needed to “debond” the particles and release them into the hoppers provided. This ‘rapping’ can damage the plates, however, and German station operators have been trying something gentler — stimulation by very intense low-frequency sound — instead. It has worked, but not always, and research has been mounted at Liverpool University in the UK to sort the problems out.
IP 530 FLYASH HANDLING, IP 202 RESEARCH, IP 538 SONIC CLEANING

PP 07 12 08 “Low-Cost Options for Moderate Levels of Mercury Control” by S. Sjostrom, ADA-ES, Inc., Littleton, CO. NTIS DE2007-899759ABS, 2006, 136 p.
ADA-ES, Inc., with support from DOE/NETL and industry partners, is conducting evaluations of EPRI’s TOXECON II process and of high-temperature reagents and sorbents to determine the capabilities of sorbent/reagent injection, including activated carbon, for mercury control on different coals and air emissions control equipment configurations. This is the final site report for tests conducted at MidAmericans Louisa Station, one of three sites evaluated in this DOE/NETL program. The other two sites in the program are MidAmericans Council Bluffs Station and Entergys Independence Station. MidAmericans Louisa Station  burns Powder River Basin (PRB) coal and employs hot-side electrostatic precipitators with flue gas conditioning for particulate control. This part of the testing program evaluated the effect of reagents used in the existing flue gas conditioning on mercury removal.
IP 412 HOT SIDE, IP 570 GAS CONDITIONING, IP 700 COSTS, IP 202 RESEARCH, IP 589 MERCURY, IP 589 SORBENT, C ADA-ES, S 4911/23 UTILITY, COAL-FIRED

PP 07 12 09 “Notice of Lodging of Consent Decree Under the Clean Air Act; United States et al. v. Evergreen Pulp, Inc.” by U.S. EPA. Federal Register, Vol. 72, No. 197, October 12, 2007, 1 p.
Notice is hereby given that on October 2, 2007, a proposed Consent Decree in United States et al, v. Evergreen Pulp, Inc, Civil Action No. C 07-05067 SBA, was lodged with the United States District Court for the Northern District of California. In this action the United States, the California Air Resources Board (ARB) and the North Coast Air Quality Management District (NCAQMD) sought civil penalties and injective relief under the Clean Air Act and state law against Evergreen Pulp, Inc. at its wood pulp mill located in Samoa, CA. The Consent Decree requires Evergreen Pulp, Inc. to: 1) Pay a civil penalty of $300,000 to the United States; 2) Pay a civil penalty of $300,000 to ARB; 3) Pay a civil penalty of $300,000 to NCAQMD; and 4) Install air pollution control equipment.
IP 150 LEGISLATION & REGULATION, IP 135 COURT ACTIONS, C EVERGREEN PULP,  2611/00 PULP MILLS

PP 07 12 10 “Use Predictive Techniques to Guide Your Mercury Compliance Strategy” by Stephen Niksa and David P. Bour, Niksa Energy Associates LLC, and Thomas A. Burnett and Naresh B. Handagama, Tennessee Valley Authority. Power, August 2007, 5 p.
Several states have mandated faster and/or deeper reductions in plant mercury emissions than those called for by the Clean Air Mercury Rule. Unfortunately, differences between plants make accurate evaluation of control options difficult. In most cases, even statistically based Hg emission models do not pass muster because they do not account for the dynamic chemical behavior of Hg species in gas cleaning systems. This article describes one system evaluation tool that has been validated using Hg field test data from 50 full-scale flue gas cleaning systems. It is already being used by TVA and other utilities.
IP 589 MERCURY, IP 591 FGD SYSTEMS, IP 272 MONITORING, C CAMR, S 4911/23 UTILITY, COAL-FIRED