Mar 1, 2012 - phosgene were also measured. The following are the ana- lytical methods used. CFCs. For CFC analysis, the exhaust gas was sampled in.
Journal of the Air & Waste Management Association
ISSN: 1096-2247 (Print) 2162-2906 (Online) Journal homepage: http://www.tandfonline.com/loi/uawm20
Destruction of Chlorofluorocarbons in a Cement Kiln Hiroyuki Ueno , Yoshiharu Iwasaki , Sukehisa Tatsuichi & Masataka Soufuku To cite this article: Hiroyuki Ueno , Yoshiharu Iwasaki , Sukehisa Tatsuichi & Masataka Soufuku (1997) Destruction of Chlorofluorocarbons in a Cement Kiln, Journal of the Air & Waste Management Association, 47:11, 1220-1223, DOI: 10.1080/10473289.1997.10464068 To link to this article: http://dx.doi.org/10.1080/10473289.1997.10464068
Published online: 01 Mar 2012.
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Ueno, Iwasaki,PAPER Tatsuichi, and Soufuku TECHNICAL
ISSN 1047-3289 J. Air & Waste Manage. Assoc. 47:1220-1223 Copyright 1997 Air & Waste Management Association
Destruction of Chlorofluorocarbons in a Cement Kiln
Journal of the Air & Waste Management Association 1997.47:1220-1223.
Hiroyuki Ueno, Yoshiharu Iwasaki, Sukehisa Tatsuichi, and Masataka Soufuku The Tokyo Metropolitan Research Institute for Environmental Protection, Tokyo, Japan
ABSTRACT One of the thermal oxidation technologies recommended by the United Nations Environment Programme (UNEP) is destruction of chlorofluorocarbons (CFCs) in a cement kiln. The destruction of CFC12, CFC11 and CFC113 was studied in a cement kiln plant in actual commercial operation. CFCs were completely destroyed in the kiln under normal operating conditions. Hydrogen fluoride and hydrogen chloride generated by CFC decomposition were absorbed by cement materials. No formation of toxic halogenated organic compounds, such as polychlorinated dibenzo-p-dioxins or dibenzofurans (PCDDs/PCDFs), was observed in the CFC incineration. INTRODUCTION Chlorofluorocarbons (CFCs) are ozone-depleting substances (ODS), commonly known as the greenhouse gases. As specific CFCs were to have stopped production at the end of 1995, according to the 1992 Montreal Protocol, they are produced in almost no countries today. In Japan, many local governments recover specific CFCs from appliances such as refrigerators and stock them. The collected CFCs are either reused or destroyed. But if reused, the CFCs still remain to be emitted into the ambient air. Therefore, we inevitably need a practical and safe method to destroy CFCs. Several destruction methods have been studied throughout the world.1-6 For example, Mizuno7 reported a new method using a plasma technique. The United
Nations Environment Programme (UNEP) 8 recommended six thermal destruction methods, including a cement kiln method. For the destruction method using a cement kiln, very few experiments had results, and few details are available. For that reason, we experimented with the CFC destruction method using a small-sized cement kiln. 9 In this paper, we report the results of our experiment, which uses a commercial kiln in actual operation. EXPERIMENT The Cement Kiln The experiment was carried out at the Chichibu Plant 2 of Chichibu Onoda Cement Corporation. The cement kiln used was a dry rotary type with a diameter of about 5.5 m and a length of 83 m, equipped with a new suspended preheater (NSP). The plant produces clinker for ordinary Portland cement, and the manufacturing capacity is about 5,000 tons per day. The fuel is mainly coal, but also waste tires and waste oil. The kiln temperature is about 1450 °C and the gas residence time is about 6–7 sec. The exhausted gas flow rate in dry base is 5,750 m3/min. Figure 1 is a simplified diagram of the cement kiln. CFCs were injected into the kiln through a main burner pipe. The air pollutant measurement point was between the electrostatic precipitator (ESP) and the stack.
IMPLICATIONS Chlorofluorocarbons (CFCs) have been widely used throughout the world. CFC emission into ambient air causes ozone depletion and greenhouse effect. Specific CFCs stopped production at the end of 1995, in accordance with the 1992 Montreal Protocol. Now in Japan, many local governments recover specific CFCs from appliances such as refrigerators and stock them. Therefore, we inevitably need a practical and safe method to destroy CFCs. This report evaluates a cement kiln method, which is one of the thermal destruction techniques recommended by United Nations Environment Programme (UNEP). Figure 1. Schematic drawing of the test kiln. 1220 Journal of the Air & Waste Management Association
Volume 47 November 1997
Ueno, Iwasaki, Tatsuichi, and Soufuku Table 1. CFC concentrations in the exhaust gas and ambient air (ppb).
Journal of the Air & Waste Management Association 1997.47:1220-1223.
CFC12 CFC11 CFC113
Blank Run n av.
min.
max.
CFC Feed n av.
min.
max.
n
Ambient Air av. min.
max.
8 2 2
