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Steel reheat furnaces

Measurement of the NOx from oxygen-enriched burners in steel reheat furnaces ... [Pg.48]

RECUPERATORS ON STEEL REHEAT FURNACES 10 Btu/hr for 170 Tona/hr Steel Throughput 480,000 0.7 x 109 per Quad of fuel 10 Times Conservation... [Pg.136]

Air Liquide, in collaboration with Physical Sciences Inc., developed a TDL instrument for temperature and species concentration measurements in heavy industrial applications. This work, sponsored by the U.S. Department of Energy (DoE), was performed befween 2000 and 2006, and involved (1) fhe development of a protofype insfrument, (2) validation tests in a small-scale Air Liquide furnace, and (3) field fesfs in three separate industrial facilities. The three industrial facilities were (1) a steel reheat furnace, (2) a reverberatory aluminum recycling furnace, and (3) an EAF. Documentation on this project is provided in a publicly available final report (Von Drasek et al. 2006). [Pg.319]

Installed FIRS DL9 burner on steel reheating furnace in Corns Llanwern Works, UK (manufacturing and installation by ICS Industrial Combustion Systems Sp.zo.o, European Licensee of NFK). [Pg.439]

For application in steel reheating furnaces, uniform temperature distribution in the entire furnace section is achieved due to dispersed flame in addition to the advantages of energy saving and low NO. Skid marks of the slab can be diminished with the dispersed flame in a steel reheating furnace. Example of skid mark reduction is shown in Figure 21.22. [Pg.439]

Fig. 1.3. Five-zone steel reheat furnace. Many short zones are better for recovery from effects of mill delays. Using end-fired burners upstream (gas-flow-wise), as shown here, might disrupt flame coverage of side or roof burners. End firing, or longitudinal firing, is most common in one-zone (smaller) furnaces, but can be accomplished with sawtooth roof and bottom zones, as shown. [Pg.11]

Fig. 1.4. Eight-zone steel reheat furnace. An unfired preheat zone was once used to lower flue gas exit temperature (using less fuel). Later, preheat zone roof burners were added to get more capacity, but fuel rate went up. Regenerative burners now have the same low flue temperatures as the original unfired preheat zone, reducing fuel and increasing capacity. Fig. 1.4. Eight-zone steel reheat furnace. An unfired preheat zone was once used to lower flue gas exit temperature (using less fuel). Later, preheat zone roof burners were added to get more capacity, but fuel rate went up. Regenerative burners now have the same low flue temperatures as the original unfired preheat zone, reducing fuel and increasing capacity.
A study of a 7 (2.13 m) high steel reheat furnace versus a 9 (2.74 m) high similar furnace (using the Shannon Method explained in chap. 8) showed that the 7 furnace required a higher average gas temperature than the 9 to heat the same load at the same rate—because of its shorter gas beam height. [Pg.47]

Suggested research project, described at the end of this chapter. No convection, conduction, or particulate radiation are included in Shannon Method calculations for steel reheat furnaces. [Pg.47]

Another example of the effect of the problem occurs with the bottom zone of a steel reheat furnace when fired longitudinally counterflow to the load movement, and with the control sensor installed 10 to 20 ft (3-6 m) from the (end-fired) burner wall. At low-firing rates, with the zone temperature set at 2400 F (1316 C), the burner wall may rise to more than 2500 F (1371 C). At that temperature, scale melts and drips to the floor of the bottom zone where it may later solidify as one big piece. At high firing rates, the peak temperature may move beyond the bottom zone T-sensor,... [Pg.52]

Fig. 4.18. Continuous steel reheat furnace, longitudinally fired in all five zones. Unless a recuperator will be above the furnace, flues at the far right bottom zone would be better than the up-flue shown (a) to minimize cold air inflow around the charge entrance and (6) for better circulation in the bottom right end of the furnace. Fig. 4.18. Continuous steel reheat furnace, longitudinally fired in all five zones. Unless a recuperator will be above the furnace, flues at the far right bottom zone would be better than the up-flue shown (a) to minimize cold air inflow around the charge entrance and (6) for better circulation in the bottom right end of the furnace.
Fig. 4.19. Continuous steel reheat furnace, side tired from both sides, staggered, not opposed, in all top and bottom zones. Fig. 4.19. Continuous steel reheat furnace, side tired from both sides, staggered, not opposed, in all top and bottom zones.
When waste heat boilers are used with steel reheat furnaces, they are often fed gases that are far above the boiler design temperature. Depending on the tightness of the furnace, 2300 F gases may reach the boiler every time there is more than a 15-min... [Pg.209]

The feed water supply is most important to protect against boiler failure. Complete dual systems to the de-aerator are essential. When the water level falls to near the bottom of the water level gauge glass, the source of heat to the boiler must be removed immediately Unlike ffiel-fired boilers, where removal of the heat sources is generally not complicated, removal of the heat source from a waste heat boiler applied to a steel reheating furnace may involve large dampers that move slowly and do not shut tightly. [Pg.209]

Preheat zones of steel reheat furnaces were formerly unfired, in line with the unfired preheat vestibule philosophy (advocated earlier in this chapter) for recovering heat from the gases exiting the soak and heat zones. However, the regenerative burners are so effective at recovering heat that their final throwaway temperature is just as low with, or lower than, an unfired preheat zone. And the furnace now has much additional... [Pg.227]

Fig. 5.27. Continuous steel reheat furnace with nine pairs of regenerative burners in three top control zones and four pairs in a bottom zone. The sweep of hot poc from side burners can alternately proceed all the way across the furnace width, avoiding the former uneven heating when opposed burners created a hot spot pileup of heat in the center when on high fire, and a cool stripe down the middle on low fire. Fig. 5.27. Continuous steel reheat furnace with nine pairs of regenerative burners in three top control zones and four pairs in a bottom zone. The sweep of hot poc from side burners can alternately proceed all the way across the furnace width, avoiding the former uneven heating when opposed burners created a hot spot pileup of heat in the center when on high fire, and a cool stripe down the middle on low fire.
Q3. Why are steel reheat furnaces without waste heat recovery so thermally inefficient in compared to boilers ... [Pg.240]

Longitudinal firing of steel reheat furnaces in top and bottom heat and soak zones, including sawtooth-roof rotary furnaces, is used to reduce the number of burners and to develop a uniform temperature across the hearth. Otherwise, most of these furnaces would be side fired to hold the heat transfer temperature higher and longer (many times for as long as 40 ft, perhaps 25 ft, for longitudinally fired zones). [Pg.245]

Fig. 6.3. Flame profile of a conventional type A flame (fig. 6.2) on a steel reheat furnace. The vertical (temperature) scale reflects the heat flux profile. ATP burners can operate at a constant high input while switching temperature profiles, for example, from 30% to 100%. Fig. 6.3. Flame profile of a conventional type A flame (fig. 6.2) on a steel reheat furnace. The vertical (temperature) scale reflects the heat flux profile. ATP burners can operate at a constant high input while switching temperature profiles, for example, from 30% to 100%.
Walking Hearth Furnace Control. The design of steel reheat furnaces has developed to such an extent that many early problems have been solved or at least remedied. However, the following are some difficulties that still cannot be estimated accurately enough to prevent concerns in final designs. [Pg.298]

Fig. 6.30. Heating curve for a three-zone steel reheat furnace top curve) and loads lower curve) In normal operation (without any delay). The billet discharge temperature is 2220 F (1215 C). Fig. 6.30. Heating curve for a three-zone steel reheat furnace top curve) and loads lower curve) In normal operation (without any delay). The billet discharge temperature is 2220 F (1215 C).
Fig. 6. 32. Heating curve for a three-zone steel reheat furnace top curve) and of the third billet to enter the furnace at the end of a 30-min delay lower curve). Discharge temperature of this third load piece is only 2000 F (1093 C)—too cold to roll. Note that the furnace temperature at the charging entrance has cooled from 1360 F (738 C) in figure 6.30 to 920 F (493 C) and furnace temperature at the entrance to the heat zone has dropped from 2140 F (1171 C) in figure 6.30 to 1450 F (788 C) in this figure 6.32. Fig. 6. 32. Heating curve for a three-zone steel reheat furnace top curve) and of the third billet to enter the furnace at the end of a 30-min delay lower curve). Discharge temperature of this third load piece is only 2000 F (1093 C)—too cold to roll. Note that the furnace temperature at the charging entrance has cooled from 1360 F (738 C) in figure 6.30 to 920 F (493 C) and furnace temperature at the entrance to the heat zone has dropped from 2140 F (1171 C) in figure 6.30 to 1450 F (788 C) in this figure 6.32.
Fig. 6. 33. Heating curve for a three-zone steel reheat furnace top curve) and of third billet lower curve) to enter the furnace after a 30-mln delay and with coauthor Shannon s system of T-sensor locations (nearer hearth for load temperature sensing and control, Instead of furnace or flame). Steel discharge temperature is 2240 F (1227 C)—good for rolling, and the furnace can resume its usual productivity more promptly after the delay. Fig. 6. 33. Heating curve for a three-zone steel reheat furnace top curve) and of third billet lower curve) to enter the furnace after a 30-mln delay and with coauthor Shannon s system of T-sensor locations (nearer hearth for load temperature sensing and control, Instead of furnace or flame). Steel discharge temperature is 2240 F (1227 C)—good for rolling, and the furnace can resume its usual productivity more promptly after the delay.
Fig. 8.5. Typical time-versus-temperature curves for a steel reheat furnace, with a side-sectional drawing aligned above the curves. Fig. 8.5. Typical time-versus-temperature curves for a steel reheat furnace, with a side-sectional drawing aligned above the curves.
Refractory Heat Loss Sample Problem 8.1—Required Fuel Inputs. An added aspect of sample problem 8.1 (the same continuous walking beam steel reheat furnace) calculate the required gross heat input to each zone. (See worksheet tables 8.14 to 8.17.). [Pg.366]

Coauthor Shannon believes that we have advanced in our understanding of scale formation in steel reheat furnaces, except for one problem—when a steel surface receives too much radiation too soon in a furnace. [Pg.387]

Case 1 Hearths In rotary-hearth steel-reheat furnaces, where load pieces are positioned directly on the hearth, the weight of the loads will cause depressions in the hearth after perhaps 6 mo. of operation. The cure for this problem is to build the hearth with stainless-steel rails built into the refractory hearth so that the ball of each rail protrudes above the top of the refractory surface 2 to 3 in. (5.8 to 7.6 cm). With this arrangement, loads are supported from deep in the hearth refractories where materials are cooler, and therefore stronger and not attacked by the furnace gases. [Pg.404]

In furnaces with bottom zones, such as pusher or walking beam steel reheat furnaces, each skid rail, on which the loads rest or slide, consists of a schedule 160 pipe, 6.625" (0.1683 m) OD with 0.718" (18.24 mm) wall thickness, through which cooling water is circulated. A solid skid wear bar is securely welded onto the top surface of the pipe. The skid wear bars are often small diameter bars of heat-resisting, wear-resisting material. Their small diameter allows less contact area with the load pieces, thereby minimizing heat loss from the loads. [Pg.414]


See other pages where Steel reheat furnaces is mentioned: [Pg.85]    [Pg.41]    [Pg.439]    [Pg.471]    [Pg.281]    [Pg.13]    [Pg.14]    [Pg.52]    [Pg.118]    [Pg.160]    [Pg.167]    [Pg.226]    [Pg.245]    [Pg.273]    [Pg.301]    [Pg.331]    [Pg.391]    [Pg.408]    [Pg.428]    [Pg.439]    [Pg.445]   
See also in sourсe #XX -- [ Pg.10 , Pg.11 , Pg.152 , Pg.154 , Pg.209 , Pg.226 , Pg.227 , Pg.228 , Pg.245 , Pg.260 , Pg.273 , Pg.331 , Pg.391 ]




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