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Show -APPLICATION-AOD VESSEL PREHEATER - MAINTAINER ... BSC STAINLESS, SHEFFIELD, U.K. ----~- DATE OF INSTALLATION - May 1984. DESCRIPTION - This reGen unit raises the temperature of a reconstructed, or maintains that of an in-use, 150 tonne (165 ton) AOD Vessel refractory lining. The original equip- ment supplied with the AOD consisted of an air/coke oven gas burner lance with O2 boost with a maximum input capability of 12 GJ/h (12 million BTU/hr), typical of that in use worldwide for this duty. The reGen System consists of a purpose bu i It 6 GJ/h (6 million BTU/hr) system with rectangular regenerators. I n normal use the unit maintains the temperature of the vessel at 980°C (1800°F) over weekend shutdown periods (around 32 hrs duration) and is used in the case of steelmaking interrupt ions du ring norma I product ion per i ods. PERFORMANCE - The reGen unit holds the AOD vessel at the desired 980°C (1800°F) with a fuel consumption of 3.0 GJ/h (3.0 million BTU/hr) - a saving of 9.0 GJ/h (9.0 million BTU/hr) over the system it replaced. It is observed that the total capital cost of the unit will be paid off in energy savings over 66 weeks if the use of the unit is confined to 32 hour weekend standbys. -APPLICATIONFORGE FURNACE A. FINKL & SONS CO., CHICAGO, ILLINOIS 82 DATE OF INSTALLATION - September 1984. EQUIPMENT - Two 3 GJ/h (3 mill ion BTU/hr) gas fired units, each compris'i'ng two burners, two regenerators and associated controls • DESCRIPTION - The furnace was a newly constructed rectangular box furnace 4.9m (16') wide, 4.3ri.l (14') deep and 2.4m (8') high. The hearth and side walls to 1.2m (4') are hard refractory, the upper walls, roof and door bei ng of ceramic fiber modules. The Regenerative Burners are mounted at high level in the rear wall, firing toward the door. The reversal system is configured to connect the two center burners as one pair, the two outer being the other pair. While a forge furnace may not normally be thought of as a dirty waste gas environment, there are several reasons why it rightly should. The high temperatures of the exhaust gases ensu res a high potent i a I for corrosi on of susceptible heat recovery devices by any volatiles in the exhaust gas stream. Typical volati les in forging furnace exhaust are sodium sulphate, calcium sulphate, and sod i um, ca Ic i um and molybdenum oxides. In the particular plant where this reGen equ i pment is i nsta lied, ceramic matr ix recuperators were both corroded and plugged by molybdenum oxides. Plugging occurred at the "cold" end of the matrix, and fluxing of the ceramic with resultant formation of low melting point eutectics caused total fai lure at the hot end. PERFORMANCE - The Regenerative Burners are providing an average air preheat of 1175°C (2150° F) at 1260°C (2300° F) furnace temperature, and an average waste gas temperature at the regenerator base of 290°C (550°F). As this was a new furnace there is no "before" data to report. I 1 I I I :1 I I I ReI~O\i,ery ing I FIGURE 10 - Chart Section from Forge Furnace |