DE1508069A1 - Procedure for operating shaft ovens - Google Patents

Description

Dipl.-Ing. H. Sauerland * "Ζ ***" ^S8 · ^{April w6fi} Patent attorneys

Bank account:

Deutsche Bank AG., Düsseldorf branch

Postichedk account: Essen 8734

Telephone number 432732

V «rw.ndtn Si« im Sdiriftvtrkehr also ungrZ.! ** "Y / Kö / SOh

Salzgitter Hüttenwerk Aktiengesellschaft, Salzgitter-Drütte

"Procedure for operating shaft furnaces"

The invention relates to a method for operating shaft furnaces, but in particular to a method for producing iron and iron alloys from iron ores in a shaft furnace, preferably in a blast furnace, with pulverulent solid fuel being introduced into the frame of the furnace.

Numerous attempts have recently been made to incorporate additional fuels into, for example, the To blow in the frame of a blast furnace, in this way to remove some of the coke that was given up at the top with the Möller to save and to reduce the specific coke consumption. For example, it is known from Swiss patent specification 276 474 to use it in the frame of a shaft furnace special gasifier heads to introduce powdery solid fuel, for example hard coal dust.

In this known process, a mixture of more than 60% of oxygen is produced outside the furnace

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Letter of April 28, 1966 .. to? .Y..eri! A] ir.eiL..Jz.um operation., Yon ». · ·" Sheet *&

tend gas and finely divided solid fuel and this mixture without further pretreatment in this way Oven frame initiated that the reaction between oxygen which only begins when the mixture enters the frame and finely divided solid fuel is essentially complete before the reaction mixture is filled with the Frame comes into contact. A notable reduction in the reduction and heat requirement of the shaft furnace However, the required coke requirement could not be achieved with this process because the amount that was blown into the frame Cold fuel draws a considerable amount of heat from the rack, resulting from the combustion of the gout abandoned coke results and must be applied by this.

The considerable heat consumption in the furnace frame by the blown solid fuel is due to the fact that the fuel is blown into the frame when it is cold and therefore first has to be brought to frame temperature by absorbing the heat of combustion of the coke given to the furnace further not inconsiderable amount of heat is required for the expulsion of the moisture contained in the coal in more or less large amounts, as well as the volatile constituents. Finally, there is a further pleasure in warmth from the fact that the volatile bed and breakfast

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from April 28, 1966 on "Procedure for the operation of« ««. " Sheet V

parts of the coal, provided that ea are hydrocarbons, and the expelled water can be split into hydrogen and carbon monoxide at the high frame temperatures. These strongly endothermic processes result in a further loss of heat in the frame.

The amount of heat required to heat the cold coal dust to the temperature of the rack to save and to counter the disadvantageous phenomenon that cold coal dust does not react with the blast furnace wind, has also already been proposed, the dusty Before introducing the fuel into the furnace frame, preheat the fuel in an externally heated tube with the exclusion of air. However, this process was also unsuccessful because the heat balance of the blast furnace despite the Preheating of the injected fuel still to a considerable extent by the solid fuel in the furnace frame is loaded with volatile constituents. This is particularly useful when using it cheaper, but also noticeably lower quality fuels.

In addition, it can be assumed that because of the high temperatures prevailing in the frame after the Boudouard's equation there just burns the carbon to carbon monoryd takes place. It follows from this, taking into account the results from the degassing and splitting

009 810/0580

For the letter dated August 2nd »April 1966 to" .Y.er.fflJir.en ZMM ... Jetri.Bb ... YQXJ. * .. «..." sheet ....%,

heat loss resulting from volatile fuel components, that the specific additional amount of heat that arises from the combustion of the injected fuel the known method is very low. In addition, the combustion temperature of the area around the blow molding is increased Mold gas is reduced accordingly by its increase by the degassing products.

The object underlying the invention now consists in part of the task given up with the Möller Replacing coke with powdery carbon, which generates the highest possible specific additional heat in the frame results and the introduction of a comparatively large amount of carbon permitted into the frame. The solution to this problem is that in the blast furnace frame solid fuel consisting practically only of pure carbon and a small proportion of ash is introduced.

More specifically, the invention consists in that fine coal is coked in an upstream the furnace coking reactor, that is, "dried and degassed, and the resulting hot fine coke is introduced in the frame, while the volatile constituents of the Peinkohle be introduced into the locking or the shaft of the furnace . For practical implementation, it is recommended that , before the extensive separation of the coke / reaction gas mixture, for example in a cyclone, a small coke pebble / gas

0 09B10 / 05S0

To the letter of April 28th, September 1st, 2006 to !! Yerf ahxfin .... for the operation of. «..." Sheet V

Branch off partial flow and use this as a carrier gas for the main amount of coke dust.

The invention is described below with reference to a device for coking of Peinkohle and for introducing the reaction products into a blast furnace explained in more detail.

The coal comes from a bunker 1 into a pipeline 2, through which it together with the through line 10 supplied combustion air is introduced into a coking reactor 3. The fed through line 10 Combustion air can be enriched with oxygen or preheated. The reaction products resulting from coking leave the coking reactor 3 via a pipe 5 opening into a cyclone 6, one of which Junction 4 leads directly to the blast furnace frame. Via junction 4, carbonaceous coking gas is used as Carrier gas for the pein coke fed into line 4 from cyclone 6 is passed into the blast furnace frame. The gaseous Reaction products of the coking reactor 3 leave the cyclone 6 via a riser 9, from which a branch 7 leads to the rest or to the shaft of the blast furnace, while a second junction 8 leads to the excessive coking gas for other use, e.g. as town gas. The riser 9 is returned to the inlet line 2, so that part of the cyclone 6

009810/0580

[to the letter dated 2.8 April ... 19.6.6 .. to '.VVerfaiireiL ... to the company, van. «» "Sheet \

leaving hot reaction gas for preheating the combustion air introduced via the pipe 10 and thus can be returned to increase the coking temperature in the coking reactor 3. In the individual pipelines control valves or slides (not shown) are installed, with the help of which the flow of the gaseous Reaction products and the pein coke can be metered.

Because the solid fuel is coked outside the blast furnace B, the blast furnace frame is practically supplied with a high concentration of carbon which is free from moisture and volatile constituents. In addition, there is produced during degassing fine coke to coking temperature, which is the usual coking at about 1000 ⁰ C and not much below the temperature at which enters the discontinued at the furnace coke in the frame. The introduction of the volatile constituents resulting from the coking of the fine coal into the rest or the shaft of the furnace leads to a further improvement in the blast furnace process. The coke gas produced is namely at the coking temperature, ie approximately at 1000 ^° C. and therefore gives off a considerable part of its heat to the charge descending in the rest or the shaft. By preheating the combustion air introduced into the coking reactor, a

009810/0580

To the letter dated April 28, 1966 to "Procedure .. to ... operation, .from. -." Sheet ...%...

substantial increase in the coking temperature and thus the Möllvorwärmung can be achieved. A higher coking temperature is expediently achieved in that as Combustion air preheated wind from the heater or oxygen-enriched air is used. When initiating of the coking gas in the rest or the shaft of the furnace is the reducing effect of the rising in the shaft Gases improved, because the proportion of reducing components, such as carbon oxide and hydrogen, increased and at the same time the nitrogen content is reduced. Also the reducing effect is favorably influenced by an increased coking temperature, because it is known that higher temperatures are used the Boudouard equilibrium largely shifted in the direction of CO formation. Thus, by introducing of the hot coking gas at suitable points in the rest area and shaft, the fuel consumption of the blast furnace can be further reduced.

The coking gas can also be used outside the blast furnace, for example to fire steam boilers, use. In addition, it can also be used for correction after adding, for example, blast furnace gas and / or natural gas of density and calorific value can be used as town or long-distance gas in accordance with the acceptance regulations.

Finally, there is a further advantage of the method according to the invention when the sulfur content

009810/0580

For writing from ... April 1966 to? .Y.ßr.fflJtlX.eXL ... ÄUHl..betrieb ... YQJX ... *. · ..!?. BIaH ... "8k.

of the degassed coal dust introduced into the rack is kept low and thus reduces the total amount of sulfur introduced into the blast furnace by the coke can be. Through the use of coal with a high proportion of degassed sulfur or through the use of heating gas With a higher hydrogen content for the degassing, the coking process can be controlled via the HpS formation in such a way that that as large a part of the sulfur present in the coal as possible passes into the gas phase. Because about 80 # of the in pig iron Existing sulfur comes from the coke and the desulfurization in steel production is costly and is difficult, makes the use of as possible low-sulfur fine coke instead of part of the Möller abandoned coke lake very beneficial noticeable. However, the advantage of the method with regard to the reduced sulfur introduction into the blast furnace only have a full effect if either the sulfur from the coke gas removed by one of the known processes or the sulfur-containing reaction gas mainly outside of the blast furnace is used, otherwise the sulfur will be fed back into the blast furnace charge and thus into the Rohelsen got.

The coal is preferably degassed by one of the known continuous processes in which im Ways of quick degassing powdery or granular coal

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For the letter dated April 28, 1.96.6. on ^{according to} Y.erfahrBiL ... aiua..Betrlel3t .. from *. · ....?. Sheet ... 3.

can be degassed within a few seconds. Coking reactors for son degassing of fine-grained or powdered coal using the moving bed, fluidized bed or plug flow method are known from the magazine "fuel chemistry", issue 10, pages 330 to 343. With such or similar This method allows almost complete degassing of the fine coal to be achieved in a very short time, which then as fine coke at coking temperature from the reactor directly is introduced into the furnace frame.

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Claims (3)

to letter dated April 28, 1966. on.! i. ¥ .er. £ ahr.ßn .... ziim ... operated by. .. · "Sheet M) Salzgitter Hüttenwerk Aktiengesellschaft, Salzgitter-Drütte Patent Claims ι 1. Process for operating shaft furnaces, in particular blast furnaces, in which pulverulent solid fuel is introduced into the furnace frame, characterized in that that fine coal coked in a coking reactor upstream of the shaft furnace and the hot one Fine coke is introduced into the frame, while the volatile components in the rest or the shaft of the furnace be initiated. 2. The method according to claim 1, characterized in that the hot fine coke with a small Part of the degassing products is introduced into the frame as a carrier gas * 3. Process according to claims 1 and 2, characterized in that the volatile constituents of the fine coal originating from the coking are used or partially outside the blast furnace. 009810/0580