Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B9/00—Stoves for heating the blast in blast furnaces
  • C21B9/14—Preheating the combustion air

Definitions

• ABSTRACT A method for operating a hot blast stove in which a combustion gas of a sulfur-containing fuel is passed through a regenerator to heat up the regenerator and air subsequently is blown through the regenerator and is heated by heat-exchange with the heat built up in the regenerator, the improvement comprising preheating the air to a temperature above the acid dew point of the combustion gas whereby corrosion of the regenerator by sulfur is prevented.
• This invention relates to a method for operating a hot blast stove in which a sulfur-containing fuel is burned.
• this invention relates to a method for operating a hot blast stove without causing corrosion of the regenerator structure.
• a fuel is burned in a combustion furnace which is separate from a regenerator, and then, the combustion gas is passed through the regenerator to transfer the heat of the combustion gas to the regenerator, with the combustion gas being passed through the regenerator for about 30 to 55 minutes to achieve a wall temperature of about 250 to 350C.
• air at room temperature is introduced into the regenerator generally from the side of the outlet of the combustion gas from the regenerator and is brought into contact with the regenerator to recover the heat as hot blast. In this case, the temperature of the section of the regenerator near the air inlet of the regenerator drops to about 50C.
• the amount of corrosion of a steel material in general. for example, is to 50 mg/dm Hr. If the lifetime of a hot blast stove can be calculated on this basis, a hot blast stove should be renewed every eight years when it is operated in the conventional method. This is about half of the inherent lifetime. Generally speaking. the inherent lifetime of a hot blast stove is about yearsv In order to avoid this, fuels containing large quantities of sulfur have not been employed as a heat source.
• .it is an object of this invention to remove these defects of the conventional methods, and to provide a method for operating a hot blast stove which permits the use of a fuel having a high sulfur content which could not be used previously.
• the present invention provides a method for operating a hot blast stove of the type in which a combustion gas of asulfurcontaining fuel is passed through a regenerator and the regenerator heated up, followed by the blowing of air through the regenerator to heat the air using the heat built up in the regenerator, comprising preheating the air to be blown through the regenerator to a temperature above the acid dew point of the combustion gas prior to blowing the air through the regenerator.
• the hot blast stove is operated so that the temperature of every part of the regenerator is not below the acid dew point of the combustion gas.
• the air to be blown for about 35 to 60 minutes through the regenerator generally at 500 to 650 Nm"/min, for producing the hot blast is pre-heated toa temperature above the acid dew point. preferably at least about C above the acid dew point, so that upon blowing the pre-heated air through the regenerator, the temperature of the regenerator is maintained always at a temperature above the acid dew point.
• the range of acid dew point of the exhaust gas can not be unequivocably defined.
• the acid dew point is dependent upon the sulfur content of the fuel, and the water content in the exhaust gas. Therefore, the heating temperature for the blast air is determined by the fuel used. Generally, a pre-heating temperature of about 200C to about 250C is sufficient.
• the preheating of the air blast can be by any known method, but a method for heating using steam, or a method of heating by circulating a part of the high temperature hot blast is preferred.
• EXAMPLE A hot blast stove which was used to provide a feed hot blast to a smelting furnace for smelting a copper ore and which had a regenerating capacity of 6,700,000 Kcal per hour was used.
• a heavy oil containing 2 percent of sulfur was burned at a rate of 1,000 liters per hour, and the burning was stopped when the temperature of the brick at the outlet of the combustion exhaust gas of the hot stove reached 350C.
• air was pre-heated to 200C with superheated steam, and then fed to the hot blast stove at a rate of 500 Nm per minute.
• the supply of the blast was stopped when the hot blast temperature fed to the smelting furnace could not be maintained at 900C, and the operation was switched over to one for regeneration.
• the time required for regeneration was about minutes, and the time for supplying the hot blast was about minutes.
• the regenerator can be heated to the desired temperature even if the combustion time is shorter than in conventional method.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Air Supply (AREA)
• Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=13284789

Family Applications (1)

Country Status (4)

Cited By (3)

Families Citing this family (1)

Citations (3)

• 1973
  • 1973-06-12 JP JP48065363A patent/JPS5014506A/ja active Pending
• 1974
  • 1974-06-04 CA CA201,650A patent/CA1080211A/fr not_active Expired
  • 1974-06-11 PH PH15931A patent/PH10883A/en unknown
  • 1974-06-12 US US478499A patent/US3902844A/en not_active Expired - Lifetime

Patent Citations (3)

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