Grantee Research Project Results
Final Report: Diminishing Materials Use and Air Pollutants in Foundries via an Integrated Advanced Oxidation Process: Characterization of Materials and Pollutants at the Nano-Scale
EPA Grant Number: R829581Title: Diminishing Materials Use and Air Pollutants in Foundries via an Integrated Advanced Oxidation Process: Characterization of Materials and Pollutants at the Nano-Scale
Investigators: Cannon, Fred S. , Voigt, Robert C. , Bhide, Harsh , Clobes, Jason , Goudzwaard, Jeff , Furness-Newburge, Jim , Firebaugh, Joel , Land, Josh , Milan-Segovia, Nohemi , Komarneni, Sridhar , Wang, Yujue
Institution: Pennsylvania State University
EPA Project Officer: Richards, April
Project Period: January 1, 2002 through December 31, 2004
Project Amount: $325,000
RFA: Technology for a Sustainable Environment (2001) RFA Text | Recipients Lists
Research Category: Sustainable and Healthy Communities , Pollution Prevention/Sustainable Development
Objective:
The objectives of this research project were to: (1) use advanced oxidation (AO) to diminish emissions and materials use in foundries that use green sand; (2) employ a consortium of protocols to characterize and better understand the nano-scale effects that this AO process has on green sand materials and air emissions; (3) experimentally identify and model AO effects as a function of distance from the molten metal interface; (4) apply this nano-scale data to enhance further the extent to which the AO process effectively preserves and activates the coal within the green sand, so that it further adsorbs and/or retains volatile organic compounds (VOCs) and thus prevents pollution before it happens; (5) apply this nano-scale data to enhance the extent to which the AO process preserves and activates clay that appears to be “dead” (i.e., unusable) in a manner that further diminishes the wasting of spent clay; and (6) interface on the validation of these improvements at full-scale foundries, via onsite trials that are informally coordinated by the Pennsylvania State University (Penn State) team in collaboration with ongoing foundry operations.
Summary/Accomplishments (Outputs/Outcomes):
Summary of Findings: Throughout the research period, tests were conducted to characterize the effects of an AO system on emission reduction and sand property improvements in green sand foundries. Emission testings were performed in both pilot-scale and full-scale iron casting foundries. In pre-production trials conducted at a pilot foundry, AO processing diminished VOC emissions by 43 percent and 27 percent for non-cored and cored castings, respectively. During production trials at a pilot foundry and at full-scale foundries, AO processing reduced VOC emissions by 63-64 percent and 26-47 percent for non-cored and cored castings, respectively. A portion of the reduced emissions occurred because the AO process allows a foundry to employ less clay (measured as methylene blue clay) and coal (measured via loss on ignition) in the green sand.
Sand system perfomance and control of the green sand system during the installation and operation of an AO system in a full-scale green sand foundry also were investigated. Significant AO process events and the corresponding sand system control actions and responses during the 2-year history of AO system start-up and operation were recorded. It was found that in foundries that employed AO systems, green compressive strength and muller efficiencies had increased immediatedly after AO system startup, and this facilitated the opportunity to diminish the consumption of bonding materials by 20-30 percent.
Experiments at Penn State aimed to reveal the mechanisms by which the AO processing had diminished the air emissions and raw material consumptions in foundries. Bench-scale and pilot-scale testings that simulated the casting processes in full-scale foundries were conducted to examine the effects of AO processing on green sand physicochemical properties and emissions. Favorable changes of green sand properties with respect to material conservation and emission reduction were observed. It was found that AO-treated green sand exhibited about twice as much pore volume and 50-100 percent higher m-xylene adsorption capacity as did non-AO-treated green sand. The AO-treated green sand also hosted 35 percent more cumulative surface charge than did the non-AO-treated green sand. Moreover, when the green sands were moisturized with AO water right before the thermogravimetric analysis (TGA), they lost 10-15 percent less mass than did the non-AO-treated green sand, in the temperature range of 344-510° C where the mass loss can be attributed primarily to coal pyrolysis. Corresponding to the less mass loss, the AO-treated green sand also released 17-22 percent less VOC emissions than did the non-AO water-moisturized green sand. The results implied that AO-initiated radical reactions at high temperatures during the casting processes might be one of the main reasons for the diminished air emissions.
At Penn State, it was found that when the clay was heated in the presence of the coal, the pyrolysis products of the coal would accumulate on the clay surface. This carbon covering rendered the clay to be hydrophobic. As a result, the clay platelets were less able to adsorb water and to bond with the sand grains. It was found, however, that AO water could displace the carbon coating readily from the clay surface. This AO treatment restored the clay’s capacity to adsorb methylene blue and water vapor. In full-scale foundries, these parameters have been tied to improved green compressive strength and mold performance.
It was found that ultrasonics, as a component of the AO system, could greatly improve the reclamation of active clay from the baghouse dust in the blackwater clarifier. When baghouse dust from a full-scale foundry received ultrasonic treatment in the laboratory, 25-30 percent of the dust classified into the clay-size fraction, whereas only 7 percent classified this way without ultrasonics. The ultrasonication also caused a size reduction of the bentonite because of the delamination of bentonite particles. The average bentonite particle diameter decreased from 4.6 mm to 3 mm, while the light-scattering surface area increased more than 50 percent after 20 minutes of ultrasonication. This would greatly improve the bonding efficiency of the bentonite according to the classical clay bonding mechanism.
Different combinations of pilot-scale AO processes were tested at Penn State. Factors that influence AO radicals generation were investigated to get a better understanding of AO chemisty and AO kinetics. It was found that with aid from the other components of AO units, namely ozone, acoustical sonication, hydrosonication and under water plasma, a given dose of H2O2 generated more OH* radicals (nearly twice as many) than if H2O2 had been employed alone. This enhancement was most dramatic for the less than or equal to 500 ppm H2O2 range. It is in this H2O2 range that the AO unit traditionally has been operating in full-scale foundries around the United States and Canada.
Conclusions:
As a newly developed technology, the AO system offers considerable application potential in foundry pollution prevention and material conservation. Full-scale foundry experiences had shown that the AO system was effective in diminishing air emission from the casting process by 20-75 percent. At the same time, the clay and coal consumption could be diminished by 20-35 percent. This would in turn diminish the amount of clay and other green sand components that would need to be landfilled or reused beneficially.
The AO processing changed the green sand system in a very profound and complicated way. The AO-treated green sand exhibited about twice as much pore volume and 50-100 percent higher m-xylene adsorption capacity as did non-AO-treated green sand after multiple casting cycles. Thus, more VOCs could be retained in the green sand mold matrix and subjected to subsequent AO degradation rather than being released as emissions. The AO processing also affected the pyrolysis behavior of the green sand. The AO-treated green sand released 10-15 percent less mass and 17-22 percent less VOC emissions than did the non-AO-treated green sand in the TGA test. In addition, the AO treatment could remove the carbonaceous condensates from the clay surface. This restored the damaged foundry properties of clay and resulted in less new clay addition requirement in full-scale foundries. The ultrasonic component of the AO system greatly improved the clay reclamation efficiency from the baghouse dust in the blackwater clarifier by detaching active clay from the sand fines surface. In addition, the ultrasonics caused a size reduction of the clay particles that improved the bonding efficiency of the clay according to the classical clay bonding mechanisms.
Journal Articles on this Report : 5 Displayed | Download in RIS Format
| Other project views: | All 8 publications | 8 publications in selected types | All 7 journal articles |
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Glowacki CR, Crandell GR, Cannon FS, Clobes JK, Voigt RC, Furness JC, McComb BA, Knight SM. Emissions studies at a test foundry using an advanced oxidation-clear water system. Transactions of the American Foundry Society 2003;111:579-598. |
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Goudzwaard JE, Kurtti CM, Andrews JH, Cannon FS, Voigt RC, Firebaugh JE, Furness JC, Sipple DL. Foundry emissions effects with an advanced oxidation blackwater system. Transactions of the American Foundry Society 2003;111:1191-1211. |
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Milan-Segovia N, Wang YJ, Cannon FS, Voigt RC, Furness JC. Comparison of hydroxyl radical generation for various advanced oxidation combinations as applied to foundries. Ozone-Science & Engineering 2007;29(6):461-471. |
R829581 (Final) |
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Wang YJ, Cannon FS, Komarneni S, Voigt RC. Mechanisms of advanced oxidation processing on bentonite consumption reduction in foundry. Environmental Science & Technology 2005;39(19):7712-7718. |
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Wang Y, Cannon FS, Neill D, Crawford K, Voigt RC, Furness JC, Glowacki CR. Effects of advanced oxidation treatment on green sand properties and emissions. Transactions of the American Foundry Society 2004;112(N 04-069):635-648. |
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Supplemental Keywords:
environmentally conscious manufacturing, air pollution, waste minimization, sustainable development, ozone, oxidants, pollution prevention, industry, sustainable industry/business, toxics, chemical engineering, chemistry, chemistry and materials science, civil/environmental engineering, environmental chemistry, environmental engineering, new/innovative technologies, sustainable environment, technology for sustainable environment, cleaner production/pollution prevention, PA, Pennsylvania, VOC removal, volatile organic compounds, VOCs, advanced oxidation process, air emissions, air pollutants, air pollutants at foundries, characterization of materials, characterization of pollutants, clean technology, cleaner production, emission controls, engineering, environmentally friendly technology, flame ionization detection, foundry industry, foundry mold and core processing, green sand mold material, green technology, hazardous emissions, industrial design for environment, industrial innovations, industry pollution prevention research, materials reduction, metal casting industry, nano-scale, process modification, RFA, Scientific Discipline, Toxics, Geographic Area, Sustainable Industry/Business, Chemical Engineering, Sustainable Environment, Environmental Chemistry, cleaner production/pollution prevention, Chemistry, VOCs, State, Technology for Sustainable Environment, Civil/Environmental Engineering, Chemistry and Materials Science, New/Innovative technologies, Environmental Engineering, characterization of materials, materials reduction, industrial design for environment, foundry industry, environmentally conscious manufacturing, sustainable development, waste minimization, air pollutants, Pennsylvania, cleaner production, environmentally friendly technology, foundary industry, waste reduction, advanced oxidation process, green sand mold material, clean technology, hazardous emissions, VOC removal, nano-scale, emission controls, metal casting industry, engineering, industry pollution prevention research, process modification, pollution prevention, air emissions, industrial innovations, Volatile Organic Compounds (VOCs), air pollutants at foundries, characterization of pollutants, PA, foundry mold and core processing, green technologyProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.