Hot-blast stoves

Heat recovery tor steam generation, pre-heating combustion air, and high efficiency burners Adjustable speed drives, heat recovery coke oven gases, and dry coke quenching Efficient hot blast stove operation, waste heat recovery for hot blast stove, top gas power recovery turbines, direct coal injection... 

Air required for combustion is furnished by turboblowers and preheated in hot-blast stoves lined with refractory-brick checker-work. Commonly,... 

Bustle Pipe or Hot-blast Circulating Duct. A metal tube of large diameter which surrounds a blast furnace at a level a little above the tuyeres it is lined with refractory material and distributes the hot air from the hot-blast-stoves to the pipes known as... 

Cowper Stove. See hot-blast stove. CPDA. Clay Pipe Development Association. 

Dome Plug. A refractory shape, usually made of aluminous fireclay or of a refractory material of still higher alumina content, used in the top of the dome of a hot-blast stove (q.v.). 

Hot-blast Main. A duct, lined with refractory material, through which hot air passes from a hot-blast stove (q.v.) to the bustle pipe (q.v.) of a blast furnace. 

Stove Fillings. The special fireclay refractory shapes used as checker bricks in a HOT-BLAST STOVE (q.v.). Normally, these stoves operate at a max. temperature (at the top of the stove) of about 1200°C the top 5m or so of fillings are therefore built with 40-42% AI2O3 refractories, with 35-37% AI2O3 refractories below. At higher hot-blast temperatures 50-65% AI2O3 stove fillings for the upper courses have been introduced. 

Air for the hot blast may also be considered a raw material. The air is preheated in stoves to between 900 and 1300°C. Over 1.5 t of air is required to produce 11 of hot metal (pig iron). SoHd, Hquid, or gaseous fuels, eg, coal, fuel oil, or natural gas, may be added to the hot blast at the tuyeres to replace some of the coke. Oxygen may also be added to the hot blast to increase flame temperature. 

After it leaves the stoves, the hot blast enters a large refractory-lined busde pipe to distribute the gas evenly around the furnace. Multiple connecting pipes (tuyere stock) direct the hot blast to the blowpipes. At the ends of the blowpipes are the tuyeres, water-cooled copper no22les set into the refractory lining of the blast furnace. 

Computer controls are likewise used for stove operation, to control deUvery of the hot blast. High hot blast temperatures are generally desirable, as these reduce the coke rate. Control of the flame temperature in the raceway is effected by controlled additions to the hot blast, primarily of moisture. Injectants into the tuyeres such as coal, oil, and natural gas are often used to replace some of the coke. The effect of these injectants on flame temperature must be accounted for, and compensation is performed by lowering moisture or adding oxygen. 

Key words Blast furnace Hot air stove Refractory Hot air channel Abstract... 

The serviee behavior of refractories used in hot air pipeline for hot air stoves in a 3200 M3 blast furnace of WISCO was analyzed. The damage faetors ean be concluded as the poor quality of andalusite based bricks, the severe thermal shoek damage, the more porosity in structures, loose bonding capability, and the unreasonable ehoiee of materials and design of bricks. By analysis, the service life of hot air stoves ean be enhaneed by the measurements such as the reasonable ehoiee of materials and their mateh, the use of light-weight refractories, the improvement of brick type, etc. Thereafter, the normal produehon operahon of hot air stoves is guaranteed. 

The hot exhaust gases, which contain some unoxidized carbon monoxide, are cleaned of dust and then are mixed with air and burned in large steel structures filled with fire brick. When one of these structures, which are called stoves has thus been heated to a high temperature the burn-ing exhaust gas is shifted to another stove and the heated stove is used to pre-heat the air for the blast furnace. 

Modern blast furnaces (Figure 6.5.10) have a volume of 5000 and produce 10 000 tonnes of Fe per day. A fixed-matrix regenerator system with periodic flow -a so-called Cowper stove, named after Edward A. Cowper (see box) - is used to preheat the blast air up to 1300 °C. The furnace is supplied with a constant flow of hot... 

The No.7 blast furnace of WISCO has been used for about 5 years and it was mid-repaired in March, 2012. The top phenomena of worn hot air pipelines are brick drop, breakage, severely local wear and deformation, existing hidden danger, so the worn hot air pipelines were renewed. Investigations have been done on the stove damage and design [1,2]. In order to elarify the wear mechanism, the used refractories for hot air pipelines were sampled and analyzed, the properties and structures of worn materials and reused materials are relatively studied. 

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