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Title	Fundamental Study on Non-Oxidizing Direct Heating Technology
Creator	Akiyama, T.; Ichizen, K.; Yoshimura, Y.; Katsuki, M; Mizutani, Y.
Publisher	Digitized by J. Willard Marriott Library, University of Utah
Date	1991
Spatial Coverage	presented at Honolulu, Hawaii
Abstract	Non-oxidizing furnace (NOF) sections have become involved into continuous annealing lines (CAL) and continuous galvanizing lines (CGL). In fact, a number of large scale lines are successfully operated also in Japanese steel mills. Such a vertical type direct heating method has the following advantages; (1) The current requirements of decreasing the furnace dimensions and layout space limit are fulfilled. (2) Reduction heating which results in better strip surface quality is permitted. (3) Due to rapid heating, improvement of metallurgical properties is expected. However, it is not yet well understood why and how the reducing (or non-oxidizing) heating of steel strip is achieved by impinging a flame at right angle, even when the air-fuel ratio is set at over 0.90 which is believed to be of oxidizing range in the theory of chemical equilibrium. This paper describes; (1) a new type nozzle mixing burner superior to the conventional ones in the capability of non-oxidizing heating, (2) experience of actual CGL with non-oxidizing direct heating zone (NOF) placed before RT burner zones, (3) experimental results obtained in a bench scale experimental furnace, aiming at clarifying the possible mechanisms in direct heating. It has been found through the experiments that the residual oxygen concentration in the flame must be lower than 0.1% by volume, and the volume ratios of CO/CO2 and H2/H2O in burnt gas should be over 0.4 and 0.09, respectively, to realize this concept.
Type	Text
Format	application/pdf
Language	eng
Rights	This material may be protected by copyright. Permission required for use in any form. For further information please contact the American Flame Research Committee.
Conversion Specifications	Original scanned with Canon EOS-1Ds Mark II, 16.7 megapixel digital camera and saved as 400 ppi uncompressed TIFF, 16 bit depth.
Scanning Technician	Cliodhna Davis
ARK	ark:/87278/s6z3226h
Setname	uu_afrc
ID	7370
Reference URL	https://collections.lib.utah.edu/ark:/87278/s6z3226h

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Title	Page 6
Format	application/pdf
OCR Text	Show application (Akiyama, 1988). Successful operation of CGL was achieved by using the y-jet gas burner, the installation list of which Table 2 shows. Operation , Oct. 1987 Auq. 1989 Mar. 1991 CoMBuSTION AIR ( r-t--=±=-:r. t] 11 ! ·'1 _f.~~JJ,.} ,: I " I t.: . ,.-I:i.l . _1._- .~,,==-="",~~-.. - ' --_.. . _-- -------·--·-I-+~3H'~ -=-+--- Fig. 3 Nozzle mix gas burner for NOF (Hot air use) Client Furnace F'ce Spec. No. ot Fuel Burner Burners Spec. SUlllitOIDO Metal Ind. ,lCeL 70 Mt/h lIax. 192 uts COG 70,000 Kcal/h WakayallA Works 200 mpm lIax. 500 C air Niaahin Steel Co., ,2CeL 65 Mt/h au. 56 .et. Butane-air 80,000 Kcal/h Ichikawa Works 60 .. pm lIIax. qa. Nakayama Steel Co., ,1CeL 32 Mt/h lUX. 84 .et. LNe 70,000 Kcal/h Funellachi Work. 57 IIIpcD .. ax. Table 2. Inatallation Li.t tor V-jet Type Nlzzle Mix Ca. Burner. IlIIplnqinq with Nor~l Anq1. to Ste.l Surface 4. FUNDAMENTAL STUDY ON NON-OXIDIZING MECHANISM In spite of the practically accomplished success in industrial experiences, nobody suggested the fundamental mechanism which explained how a high temperature mixture and an oxidizing flame (or combustion products) behave in the proximity of steel surface keeping it unoxidized. It is also uncertain about furnace design parameters and operating conditions of a non-oxidizing furnace section which determine the steel surface oxidation limit. - 5 -
Setname	uu_afrc
ID	7359
Reference URL	https://collections.lib.utah.edu/ark:/87278/s6z3226h/7359