DE1086165B - Method for operating a gas or oil-heated shaft furnace - Google Patents

Description

Method for operating a gas- or oil-heated shaft furnace The invention relates to the operation of a gas or oil-heated shaft furnace, in particular lime kiln, the burners of which are arranged in the outer wall and those with devices for injecting incombustible gases above the burners and devices is equipped for the lateral extraction of cooling air below the burner.

Shaft furnaces for lumpy items where the fuel is in Form of generator gas, coal dust, oil or the like. Laterally by means of the furnace wall burner located outside the bulk material is introduced, in particular lime kilns, have the disadvantage that the furnace lining is above the fuel introduction point is severely affected by local overheating, since the in the furnace shaft rising air, which serves as a coolant for the sinking material, feeds the fuel and the flame rips up and presses against the masonry. In the locally intensive Mixing gas and air therefore creates very high combustion temperatures.

To avoid impermissibly high temperatures on the shaft wall of the As a result, the fuel must pass through the burner in the lower combustion zone, without or can only be introduced with a small amount of air added. In this way, however, can overheating of the shaft wall does not completely fix it, since it is close to the furnace wall Air rising from the cooling zone hits the inflowing fuel, as a result of which high flame temperatures arise that even high-quality oven linings cannot are sufficiently resistant.

To avoid local overheating, the burners are completely or partially guided into the furnace axis. However, such burners protruding into the shaft are subject to high mechanical and thermal stress.

To ensure that the items to be fired sink evenly in the shaft and evenly To achieve a distributed rise of the hot gases over the shaft cross-section, is Furthermore, the shaft cross-section through vertical partitions into a series of individual shafts have been divided, each provided with a number of burners. Above the Burners are thereby arranged exhaust gas feeds through which by mixing with the fuel gas a uniform distribution of the combustion over the cross-section the individual shafts are supposed to cause.

Local overheating also occurs in this known shaft furnace cannot be completely avoided, as the warm air rising from below in the area of the shaft wall mixes directly with the fuel flowing out of the burners and the hot flame, at least partially, steers against the 2 shaft wall, even before a distribution of the exhaust gas supplied above begins.

It is also a method of burning lime in a shaft furnace known, in which the hot air of the cooling zone is withdrawn from the shaft and into the combustion zone, especially in the middle or upper part of the combustion zone.

The invention now consists in operating the shaft furnace in such a way that that the injection pressure of the non-flammable gases as well as the suction at the lateral discharge points the cooling air is dimensioned so that by the interaction of the Pressure conditions inside the furnace keep the flames away from the outer wall and towards it be steered towards the furnace axis.

In a furnace operated in accordance with the invention in this way, through corresponding adjustment of the suction of the cooling air to be withdrawn achieved that only in the area of the shaft wall there is an immediate mixing of the rising, hot Avoid cooling air with the fuel emerging from the burners and at the same time the flame through the suction in conjunction with the pressure of the above the burner Introduced exhaust gas in a substantially horizontal direction to the furnace axis is steered. The exhaust gas drawn off above the burner forms a heat protection curtain between the shaft wall and the material to be fired.

The drawing shows an exemplary embodiment of the invention.

It shows a vertical section through one according to the invention trained, schematically shown shaft furnace.

The shaft 1 is from above via a funnel 2 in a known manner covered with limestone. Of the Limestone migrates according to that progressive firing process down and reaches the firing zone A. The lower The end of the combustion zone is provided with openings into which gas burners 4 open.

Above the burner 4 are 3 lines in the individual openings 5 for introducing protective gas under pressure, for example from the upper end of the shaft withdrawn exhaust gas, introduced, which in a heat exchanger part of the sensible Heat can be withdrawn.

Immediately below each burner 4 is the shaft wall with a Suction opening 7 is provided, through which part of the from below through a cooling zone B sucked in air is sucked off in the area of the shaft wall.

The pressure of the exhaust gas introduced through the lines 5 and the suction the cooling air withdrawn through the shaft wall openings 7 are now coordinated in such a way that that the Drenner flame is deflected in the direction of the shaft axis without being in the area the shaft wall a substantial mixing of the rising cooling air with the Combustion gas of the burner can be done. The burnt lime leaves below the saddle 8 through the discharge devices the furnace shaft.

Claims (1)

PATENT CLAIM: A method for operating a gas or oil-heated shaft furnace, in particular a lime kiln, the burners of which are arranged in the outer wall and which is equipped with devices for blowing in incombustible gases above the burners and devices for the lateral extraction of cooling air below the burners, characterized in that, that the injection pressure of the non-flammable gases and the suction at the side draw-off points of the cooling air is so dimensioned that the flames are directed away from the outer wall and in the direction of the axis of the furnace through the interaction of the pressure conditions created within the furnace. Considered publications: German Patent Nos. 186196, 351196, 1008 641; U.S. Patent No. 2,470,543.