Characterization of Hydrocarbon Emissions from Green Sand Foundry Core Binders by Analytical Pyrolysis

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• 作者：Yujue Wang ; Fred S. Cannon ; Magda Salama ; Jeff Goudzwaard ; and James C. Furness
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：November 15, 2007
• 年：2007
• 卷：41
• 期：22
• 页码：7922 - 7927
• 全文大小：159K
• 年卷期：v.41,no.22(November 15, 2007)
• ISSN：1520-5851

文摘

Analytical pyrolysis was conducted to study a relativecomparison of the hydrocarbon and greenhouse gasemissions of three foundry sand binders as follows: (a)conventional phenolic urethane resin, (b) biodiesel phenolicurethane resin, and (c) collagen-based binder. Thesebinders are used in the metal casting industry for makingcores that are used to create internal cavities withincastings. In this study, the core samples were flash pyrolyzedin a Curie-point pyrolyzer at 920 C with a heating rateof about 3000 C/sec. This simulated some key features ofthe fast heating conditions that the core binders wouldexperience at the metal-core interface when molten metalis poured into green sand molds. The core sampleswere also pyrolyzed in a thermogravimetric analyzer (TGA)from ambient temperature to 1000 C with a heating rateof 30 C/min, and this simulated key features of the slowheating conditions that the core binders would experienceat distances that are further away from the metal-coreinterface during casting cooling. Hydrocarbon emissionsfrom flash pyrolysis were analyzed with a gas chromatography-flame ionization detector, while hydrocarbon andgreenhouse gas (CO and CO₂) emissions from TGApyrolysis were monitored with mass spectrometry. Theprominent hazardous air pollutant emissions during pyrolysisof the three binders were phenol, cresols, benzene, andtoluene for the conventional phenolic urethane resin andbiodiesel resin, and they were benzene and toluene for thecollagen-based binder. It was also found that volatileorganic compound and polycyclic aromatic hydrocarbonemissions considerably decreased in order from conventionalphenolic urethane resin to biodiesel resin to collagen-based binder. These results have shown some similaritywith those for stack emission testing conducted atdemonstration scale and/or full-scale foundries, and thesimilar trends in the two sets of results offered promise thatbench-scale analytical pyrolysis techniques could be auseful screening tool for the foundries to compare therelative emissions of alternative core binders and to chooseproper materials in order to comply with air-emissionregulations.