Document Detail


Evaluation on thermal explosion induced by slightly exothermic interface reaction.
MedLine Citation:
PMID:  15363527     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
An asphalt-salt mixture (ASM), which once caused a fire and explosion in a reprocessing plant, was prepared by imitating the real bituminization process of waste on a lab scale to evaluate its actual thermal hazards. Heat flux reaction calorimeters were used to measure the release of heat for the simulated ASM at a constant heating rate and at a constant temperature, respectively. Experimental results show that the reaction in the ASM below about 250 degrees C is a slightly exothermic interface reaction between the asphalt and the salt particles contained in the asphalt, and that the heat release rate increases sharply above about 250 degrees C due to melting of the salt particles. The reaction rates were formulated on the basis of an assumed reaction model, and the kinetic parameters were determined. Using the model with the kinetic parameters, temperature changes with time and drum-radius axes for the ASM-filled drum were numerically simulated assuming a one-dimensional infinite cylinder system, where the drum was being cooled at an ambient temperature of 50 degrees C. The minimum filling temperature, at which the runaway reaction (MFTRR) can occur for the simulated ASM in the drum is about 194 degrees C. Furthermore, a very good linear correlation exists between this MFTRR and the initial radius of salt particles formed in the bituminization product. The critical filling temperature to the runaway reaction is about 162 degrees C for the asphalt-salt mixture, containing zero-size salt particles, filled in the same drum at an ambient temperature of 50 degrees C. Thus, the runaway reaction will never occur in the drum filled with the asphalt-salt mixture under the conditions of the filling temperature below 162 degrees C and a constant ambient temperature of 50 degrees C. As a consequence, the ASM explosion occurred in the reprocessing plant likely was due to a slightly exothermically reaction and self heating.
Authors:
Ma-Hong Yu; Yong-Fu Li; Jin-Hua Sun; Kazutoshi Hasegawa
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Publication Detail:
Type:  Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of hazardous materials     Volume:  113     ISSN:  0304-3894     ISO Abbreviation:  J. Hazard. Mater.     Publication Date:  2004 Sep 
Date Detail:
Created Date:  2004-09-14     Completed Date:  2005-02-25     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9422688     Medline TA:  J Hazard Mater     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  165-74     Citation Subset:  IM    
Affiliation:
School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China. yumahong@mail.njust.edu.cn
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MeSH Terms
Descriptor/Qualifier:
Explosions*
Hazardous Substances*
Hydrocarbons / chemistry*
Kinetics
Models, Chemical
Salts / chemistry*
Thermodynamics
Chemical
Reg. No./Substance:
0/Hazardous Substances; 0/Hydrocarbons; 0/Salts; 8052-42-4/asphalt

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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