The Clean Air Act Amemdments of 1990 mandated emissions levels for SO2 and NOx and on the horizon is the potential regulation of hazardous air pollutants (HAPS). This legislation has resulted in the need for developing technologies for reducing the amount of SO2, NOx, particulates and HAPS in flue gas. CUC personnel have fourteen years of research into studying the formation and remediation of SO2 emissions produced during combustion. The CUC is equipped to conduct EPA Method sampling and analysis of HAPS in a variety of test equipment.
The CUC is actively involved in characterizing and reducing emissions from fossil fuel-fired boilers. Emissions specifically being addressed are SO2, NOx, fine particulates (PM2.5), trace elements, and volatile organic compounds. Activities include sorbent performance evaluation in fluidized-bed combustors, limestone reagent performance in wet flue gas desulfurization (WFGD) applications, and cofiring coal-water slurry fuel (CWSF) with pulverized coal for NOx reduction, all of which primarily focus on cogeneration facilities and utility boilers. Those activities which are related to industrial boilers include: characterizing air toxic emissions; evaluating ceramic filter systems to remove fine particulate matter; evaluating sorbent injection to reduce SO2 and SO3 emissions; and identifying/developing a selective catalytic reduction (SCR) catalyst for NOx reduction that is compatible with the typical operating conditions and economic constraints of industrial boilers.
Relevant Publications
SO2 Emissions
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Twenty-five well-characterized limestones were evaluated as reagents in a pilot-scale, forced-oxidation wet flue gas desulfurization (WFGD) test facility. Limestone performance was determined as the extent and rate of sulfur capture as a function of time and the dissolved carbonate/sulfur capture molar ratio. A data base was generated of the relative performance of the limestones, which represented a range of stratigraphic intervals with diverse chemical compositions, and geologic histories.
The study suggests that limestones with as little as 82 wt. % calcium carbonate are suitable reagents based on the defined performance parameters. Relative performance was not predictable solely from the calcium carbonate content. The effect on limestone performance of operating parameters, i.e. liquid-to-gas ratio, gas-liquid contact time, residence time in the reaction tank, pH, and SO2 concentration, and slurry characteristics, i.e., solids loading and particle size distribution, was also investigated.
Results of the program include:CUC personnel have experience in sorbent injection into coal-fired boilers for SO2 control. This includes in-furnace and duct injection technologies for pulverized and micronized coal-fired boilers. Currently the CUC is evaluating sodium bicarbonate duct injection into the flue gas from a micronized coal-fired industrial boiler to achieve 90% SO2 emissions, and to reduce SO3 emissions to minimize ammonium bisulfate deposition during NOx reduction from a SCR system. Penn State's demonstration boiler system is being used for this demonstration.
The CUC is actively involved in the development and evaluation of low-NOx burners for industrial boilers. This includes burner and boiler modeling, burner performance evaluation, and new burner development. Low-NOx burner evaluation and development activities have been conducted in conjunction with ABB Combustion Engineering (High Efficiency Advanced Coal Combustor and Radially Stratified Fuel Core burner) and Energy and Environmental Research Corporation (FlamemastEERTM burner) using the demonstration boiler.
A NOx reduction catalyst is being identified/developed at the CUC, in conjunction with Englehard Corporation, that is compatible with the typical operating conditions and the economic constraints of industrial boilers. The optimum temperature for SCR catalysts currently being used is ~700oF. The objective of the low-temperature catalyst work is to operate a SCR system at typical baghouse temperatures (~350-400oF). This work has progressed from a bench-scale laboratory reactor to the pilot scale (100 acfm) and is being scaled up to the demonstration boiler (8,150 acfm). The catalyst is being developed for two applications -- as a monolith supported catalyst on the clean side of a conventional baghouse and as a coating on a ceramic filter. The CUC is collaborating with Englehard Corporation, CeraMem Corporation, and Babcock & Wilcox on this activity.
The CUC is demonstrating the removal of ultrafine particulate matter with increased particulate collection efficiency through the use of a ceramic filter. A ceramic filtering device is operated in parallel with the fabric filter baghouse to evaluate this new technology, contrast it with conventional filtration, and demonstrate a smaller, more efficient filtering device for boiler retrofit applications. The CUC verifies particulate loading utilizing EPA Methods 5 and 201 (PM-10)
The CUC is studying the occurrence of trace metals in flue gas in both pilot- and demonstration-scale facilities utilizing EPA sampling and analytical techniques outlined in Methods 5 and 29. Of particular interest is the effect of coal cleaning techniques on the amount of specific trace metals in the flue gas and ash. The CUC is also conducting tests evaluating the effect of different particulate removal systems, i.e., conventional baghouse and ceramic filter, on trace metals. Particular attention is given to mercury, arsenic and selenium.
The primary solid product at the completion of combustion is fly ash. One area of evolving technologies is the use of such as a by-product. The CUC collaborates with the Material Research Laboratory, Penn State University characterizing and determining the suitability of ash for use in building materials, stabilization material for ash disposal sites and acid mine drainage treatment.
The CUC has participated in and conducted several different forums that involve the dissemination of information to sponsors and the general public. The CUC has provided invited speakers to present the results of specific projects of interest to certain industry organizations and conferences. The CUC has also hosted several international delegations interested in its research and facilities.
Listed are a few of the types of activities that the CUC has participated in:
Relevant PresentationsPage 1 2
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