OCR Text |
Show 8 In spite of the removal of the conventional flue when the regenerative burner system was applied, it is thought that about 1 0 % of exhaust escape occurs since a certain amount of gap around the door is seen and moreover the furnace pressure of +10 Pa is maintained. Therefore, the exhaust temperature from the regenerator element is around 250°C as shown in Fig. 8, but it is thought that the temperature may be about 100°C higher when in a complete no-escape condition. 180 °E 150 © a 120 -f- ^=w*n :/ fJjT Af ter^ application\ > k ^ \ x [mf*^ TT~* >1 T ^ [m%*** J" ^ / 8 888 8 8 8 8 8 8 8 888888 88888 OD 6i 6 »• c j c o o ^ - o j o r r i n i p r ^ c o b S o »- c\i o eo «*• 1400 r »- <- CM OJ CY CM Time Fig. 7 Comparison of consumed fuel per day I eoo <D before and after the application 2.4.2 NOx value As shown in Fig. 9, NOx value at peak is 200 ppm (02=0% conversion) and this clears the Japanese regulation by a wide margin but there are some regenerative burners used in large furnaces, such as for hot rolling which achieve ultra low N Ox values of about 100 ppm. Compared with such, the PAX-R burner is not necessarily the lowest in NOx value. However this is because the PAX-R burner was developed, based on the concept of 0 simple control, @ low pressure drop, (D securing of stable combustion at low temperatures, and @ compactness. 400 200 0 Furnace temperature Pre-heated air temperature Flue gas temperature 50 100 150 Time min 200 250 Fig. 8 Main measured values of the forage furnace with the PAX-R burner Air ratio =1.1 exhaust escape = 0% 250 E § 200 x O Z 150 •D CD 0) > 100 o oo II 50 ::::: -^f< :::::: Z^T- u Lo« r idfactor=100% - A% f jf JT\ ::::::::::: . -jp . .oad factor=80% _^s^- |_oaCj factor L7TTTL oad factor-40% =60% ;: 1 !-- 1 800 1000 1200 Furnace temperature ^C 1400 Fig. 9 NOx characteristics of the PAX-R burner |