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Title: Combustion and inorganic bromine emission of waste printed circuit boards in a high temperature furnace

Abstract

Highlights: Black-Right-Pointing-Pointer The combustion efficiency of waste printed circuit boards (PCBs) depends on temperature, excess air factor, and high temperature zone residence time. Temperature has the most significant impact. Under the proposed condition, combustion of waste PCBs alone is quite complete within the furnace. Black-Right-Pointing-Pointer High temperature prompts a more complete bromine release and conversion. When temperature is high enough, 99.9% organobrominated compounds, the potential precursors for brominated dixoins formation, are destroyed efficiently and convert to inorganic bromine in flue gas, as HBr and Br{sub 2}. Black-Right-Pointing-Pointer Temperature has crucial influence over the inhibition of HBr conversion to Br{sub 2}, while the oxygen partial pressure plays a reverse role in the conversion to a very small extent. Increasing temperature will decrease the volume percentage ratio of Br{sub 2}/HBr in flue gas greatly. Black-Right-Pointing-Pointer The thermodynamic equilibrium approach of bromine conversion was investigated. The two forms of inorganic bromine in flue gas substantially reach thermodynamic equilibrium within 0.25 s. Under the proposed operating condition, the reaction of Br transfer and conversion finish. - Abstract: High temperature combustion experiments of waste printed circuit boards (PCBs) were conducted using a lab-scale system featuring a continuously-fed drop tube furnace. Combustion efficiency and the occurrencemore » of inorganic bromine (HBr and Br{sub 2}) were systematically studied by monitoring the main combustion products continuously. The influence of furnace temperature (T) was studied from 800 to 1400 Degree-Sign C, the excess air factor (EAF) was varied from 1.2 to 1.9 and the residence time in the high temperature zone (RT{sub HT}) was set at 0.25, 0.5, or 0.75 s. Combustion efficiency depends on temperature, EAF and RT{sub HT}; temperature has the most significant effect. Conversion of organic bromine from flame retardants into HBr and Br{sub 2} depends on temperature and EAF. Temperature has crucial influence over the ratio of HBr to Br{sub 2}, whereas oxygen partial pressure plays a minor role. The two forms of inorganic bromine seem substantially to reach thermodynamic equilibrium within 0.25 s. High temperature is required to improve the combustion performance: at 1200 Degree-Sign C or higher, an EAF of 1.3 or more, and a RT{sub HT} exceeding 0.75 s, combustion is quite complete, the CO concentration in flue gas and remained carbon in ash are sufficiently low, and organobrominated compounds are successfully decomposed (more than 99.9%). According to these results, incineration of waste PCBs without preliminary separation and without additives would perform very well under certain conditions; the potential precursors for brominated dioxins formation could be destroyed efficiently. Increasing temperature could decrease the volume percentage ratio of Br{sub 2}/HBr in flue gas greatly.« less

Authors:
 [1]; ; ; ; ;  [1]
  1. State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027 (China)
Publication Date:
OSTI Identifier:
21612949
Resource Type:
Journal Article
Journal Name:
Waste Management
Additional Journal Information:
Journal Volume: 32; Journal Issue: 3; Other Information: DOI: 10.1016/j.wasman.2011.10.016; PII: S0956-053X(11)00475-2; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0956-053X
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 54 ENVIRONMENTAL SCIENCES; AIR POLLUTION MONITORING; ASHES; BROMINE; CARBON MONOXIDE; COMBUSTION; DIOXIN; EFFICIENCY; EMISSION; FLAMES; FLUE GAS; FURNACES; HYDROBROMIC ACID; OXYGEN; PARTIAL PRESSURE; PRINTED CIRCUITS; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0400-1000 K; THERMODYNAMICS; BROMINE COMPOUNDS; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; CHEMICAL REACTIONS; COMBUSTION PRODUCTS; ELECTRONIC CIRCUITS; ELEMENTS; GASEOUS WASTES; HALOGEN COMPOUNDS; HALOGENS; HETEROCYCLIC COMPOUNDS; HYDROGEN COMPOUNDS; INORGANIC ACIDS; INORGANIC COMPOUNDS; MONITORING; NONMETALS; ORGANIC COMPOUNDS; ORGANIC OXYGEN COMPOUNDS; OXIDATION; OXIDES; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES; RESIDUES; TEMPERATURE RANGE; THERMOCHEMICAL PROCESSES; THERMODYNAMIC PROPERTIES; WASTES

Citation Formats

Ni Mingjiang, E-mail: xiaohanxi_2@163.com, Hanxi, Xiao, Chemistry and Chemical Engineering School, Hunan University of Science and Technology, Xiangtan, Yong, Chi, Jianhua, Yan, Buekens, Alfons, Yuqi, Jin, and Shengyong, Lu. Combustion and inorganic bromine emission of waste printed circuit boards in a high temperature furnace. United States: N. p., 2012. Web.
Ni Mingjiang, E-mail: xiaohanxi_2@163.com, Hanxi, Xiao, Chemistry and Chemical Engineering School, Hunan University of Science and Technology, Xiangtan, Yong, Chi, Jianhua, Yan, Buekens, Alfons, Yuqi, Jin, & Shengyong, Lu. Combustion and inorganic bromine emission of waste printed circuit boards in a high temperature furnace. United States.
Ni Mingjiang, E-mail: xiaohanxi_2@163.com, Hanxi, Xiao, Chemistry and Chemical Engineering School, Hunan University of Science and Technology, Xiangtan, Yong, Chi, Jianhua, Yan, Buekens, Alfons, Yuqi, Jin, and Shengyong, Lu. Thu . "Combustion and inorganic bromine emission of waste printed circuit boards in a high temperature furnace". United States.
@article{osti_21612949,
title = {Combustion and inorganic bromine emission of waste printed circuit boards in a high temperature furnace},
author = {Ni Mingjiang, E-mail: xiaohanxi_2@163.com and Hanxi, Xiao and Chemistry and Chemical Engineering School, Hunan University of Science and Technology, Xiangtan and Yong, Chi and Jianhua, Yan and Buekens, Alfons and Yuqi, Jin and Shengyong, Lu},
abstractNote = {Highlights: Black-Right-Pointing-Pointer The combustion efficiency of waste printed circuit boards (PCBs) depends on temperature, excess air factor, and high temperature zone residence time. Temperature has the most significant impact. Under the proposed condition, combustion of waste PCBs alone is quite complete within the furnace. Black-Right-Pointing-Pointer High temperature prompts a more complete bromine release and conversion. When temperature is high enough, 99.9% organobrominated compounds, the potential precursors for brominated dixoins formation, are destroyed efficiently and convert to inorganic bromine in flue gas, as HBr and Br{sub 2}. Black-Right-Pointing-Pointer Temperature has crucial influence over the inhibition of HBr conversion to Br{sub 2}, while the oxygen partial pressure plays a reverse role in the conversion to a very small extent. Increasing temperature will decrease the volume percentage ratio of Br{sub 2}/HBr in flue gas greatly. Black-Right-Pointing-Pointer The thermodynamic equilibrium approach of bromine conversion was investigated. The two forms of inorganic bromine in flue gas substantially reach thermodynamic equilibrium within 0.25 s. Under the proposed operating condition, the reaction of Br transfer and conversion finish. - Abstract: High temperature combustion experiments of waste printed circuit boards (PCBs) were conducted using a lab-scale system featuring a continuously-fed drop tube furnace. Combustion efficiency and the occurrence of inorganic bromine (HBr and Br{sub 2}) were systematically studied by monitoring the main combustion products continuously. The influence of furnace temperature (T) was studied from 800 to 1400 Degree-Sign C, the excess air factor (EAF) was varied from 1.2 to 1.9 and the residence time in the high temperature zone (RT{sub HT}) was set at 0.25, 0.5, or 0.75 s. Combustion efficiency depends on temperature, EAF and RT{sub HT}; temperature has the most significant effect. Conversion of organic bromine from flame retardants into HBr and Br{sub 2} depends on temperature and EAF. Temperature has crucial influence over the ratio of HBr to Br{sub 2}, whereas oxygen partial pressure plays a minor role. The two forms of inorganic bromine seem substantially to reach thermodynamic equilibrium within 0.25 s. High temperature is required to improve the combustion performance: at 1200 Degree-Sign C or higher, an EAF of 1.3 or more, and a RT{sub HT} exceeding 0.75 s, combustion is quite complete, the CO concentration in flue gas and remained carbon in ash are sufficiently low, and organobrominated compounds are successfully decomposed (more than 99.9%). According to these results, incineration of waste PCBs without preliminary separation and without additives would perform very well under certain conditions; the potential precursors for brominated dioxins formation could be destroyed efficiently. Increasing temperature could decrease the volume percentage ratio of Br{sub 2}/HBr in flue gas greatly.},
doi = {},
journal = {Waste Management},
issn = {0956-053X},
number = 3,
volume = 32,
place = {United States},
year = {2012},
month = {3}
}