Evaluation of Volatile Hydrocarbon Emission Characteristics of Carbonaceous Additives in Green Sand Foundries
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- 作者：Yujue Wang ; He Huang ; Fred S. Cannon ; Robert C. Voigt ; Sridhar Komarneni ; James C. Furness
- 刊名：Environmental Science & Technology
- 出版年：2007
- 出版时间：April 15, 2007
- 年：2007
- 卷：41
- 期：8
- 页码：2957 - 2963
- 全文大小：167K
- 年卷期：v.41,no.8(April 15, 2007)
- ISSN：1520-5851
文摘
This research studied a relative comparison of thehydrocarbon emissions during pyrolysis of four carbonaceousadditives that can be used in green sand foundries.These included a highly volatile bituminous coal, anthracite,lignite, and cellulose. Analytic pyrolysis was conductedto simulate the heating conditions that the carbonaceousadditives would experience during metal pouring.Specifically, the samples were flash pyrolyzed in a Curie-point pyrolyzer at 920 
C with a heating rate of about3000 C/sec. This simulated some key features of the fastheating conditions that the carbonaceous additiveswould experience at the metal-mold interface whenmolten metal is poured into green sand molds. The sampleswere also pyrolyzed in a thermogravimetric analyzer(TGA) from ambient temperature to 1000 C with a heatingrate of 20 C/min; and this simulated key features of theslow heating conditions that the carbonaceous additiveswould experience within the bulk of green sand molds thatis further away from the metal-mold interface. Hydrocarbonemissions from flash pyrolysis were analyzed with GC-FID, while those from TGA pyrolysis were monitored withmass spectroscopy and GC-FID. The anthracite exhibitedvery low volatile hydrocarbons during both flash pyrolysisand TGA pyrolysis. The cellulose released less hydrocarbonsthan bituminous coal or lignite in TGA pyrolysis, but morehydrocarbons than those two during flash pyrolysis. Thismeans that cellulose can release sufficient volatilehydrocarbons at the intensely heated molten metal-moldinterface where they are most desired for ensuringcasting quality, but much less within the bulk of the moldwhere they are undesirable. This characteristic ofcellulose offers an important opportunity for green sandfoundries to diminish their hazardous air pollutant (HAP)emissions.
C with a heating rate of about3000 C/sec. This simulated some key features of the fastheating conditions that the carbonaceous additiveswould experience at the metal-mold interface whenmolten metal is poured into green sand molds. The sampleswere also pyrolyzed in a thermogravimetric analyzer(TGA) from ambient temperature to 1000 C with a heatingrate of 20 C/min; and this simulated key features of theslow heating conditions that the carbonaceous additiveswould experience within the bulk of green sand molds thatis further away from the metal-mold interface. Hydrocarbonemissions from flash pyrolysis were analyzed with GC-FID, while those from TGA pyrolysis were monitored withmass spectroscopy and GC-FID. The anthracite exhibitedvery low volatile hydrocarbons during both flash pyrolysisand TGA pyrolysis. The cellulose released less hydrocarbonsthan bituminous coal or lignite in TGA pyrolysis, but morehydrocarbons than those two during flash pyrolysis. Thismeans that cellulose can release sufficient volatilehydrocarbons at the intensely heated molten metal-moldinterface where they are most desired for ensuringcasting quality, but much less within the bulk of the moldwhere they are undesirable. This characteristic ofcellulose offers an important opportunity for green sandfoundries to diminish their hazardous air pollutant (HAP)emissions.