DE2032400A1 - Refuse derived fuel as part of the blast furnace charging - Google Patents

Description

8289-70 / Dr.U.

U.S. Serial Uo. 837.575

filed: June.30, 1969

BAILEY IiJVENl ¹ IONS, INC. 3502 Chipr. On Road, Easton, Pennsylvania / USA

"Substitute fuel as part of the fan shaft furnace charging"

The present invention relates to the reduction of sisen in the Fan shaft furnace.

One of the objectives of U.S. ^ Pat ent 3 3 ^ 6 367 of the same Applicant was to enable a mode of operation in the fan shaft furnace, in which the withdrawing furnace gases one that is too low for later recycling in ovens Content of CO and H "included.

This was done by introducing secondary air into the upper zone of the furnace and restricting the reaction of the secondary air on the combustion of CO and Hp, which by the upper

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Zone, reached in order to prevent the consumption of fuel while this migrates down through the upper zone and ura as much of the thermal energy of the fuel as possible for a release in form: of CO in a lower zone Zone to get aort the high ₃ required for the reduction of the liisen ore. Generate content of gaseous CO.

The mode of operation in the fan shaft is consistent with the present invention maintains the achievement of this goal, but additionally takes note of the fact that the production of coke itself i: a coke oven entails a loss of units of heat before the process has ever started in the fan shaft furnace.

Ss is therefore an object of the present invention which Invention of the earlier patent to the effect that not only the previously lost heat units in the escaping Top gas, but also the now lost from the fuel in the coke ovens in the course of the production of the coke fuel for its use in the fan shaft furnace Thermal units are released.

In short, the present invention transfers the

coking process from the conventional coke oven into the fan

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oon-ichtofen. Lie introduces the material into the fan shaft furnace - which was previously fed to the coke oven, namely ..ji.ue. ^ he converts the raw (ie uncoked ^ although possibly briquetted) coal into coke within the fan: .acntofeiirf - by driving off the volatile substances of the coal 1. ·! t Inei 'ooeren zone of the furnace to where these with the above ues ..iveauo oer "eduktionszone introduced secondary air rea _t;. ier.3n, such that these volatile substances within the jebläsesehachvofens ait any carbonic oxide or V / on Hydrogen content "burn ascending in. from the reducing zone JLser. Vu. these coking in the top

des. C te ns without consumption of solid carbon of coal izuf Ü-iren,. -suitable means are provided for the coal •. • ■ • ar.renä äes coking <_s process before, through the upper or Yeiv.okuHoS-tcne to protect or invade rising gases, in a manner similar to the original filling of the coke described in US Pat. No. 3,3 · '' 3t7. However, to the Operation of the present invention in the event that ■ the ■■ "J.-huilune, is a co-elder and, v; ie here, instead of vo-r'jeforr.ter .. contains coke to coke, It is essential to vent the container in such a way that the 'volatile constituents of the coal to the extent that they are set free, expand and out of the container sur combustion in the surrounding, rising gas stream can flow out. This is done by

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makes the container gas-permeable. A higher differential pressure: inside the container, which is due to the expanding Volatiles caused keeps the rising gases from coming into contact with the coal or the coke inside of the container.

In addition, the containers for the coal to be coked are made of metal, which bears the load of the falling charge. They can be made of metal such as steel, iron or some other fusible material that will alloy with your iron from the ore. The encapsulating material should be as in the case of US Patent 3346367 have a melting point of about 1538 ⁰ C (280O ⁰ F) - The containers may be made in a cylindrical, round, cube-shaped or other rectilinear form of tubes, stampings or Gußwaren be. The wall thickness should vary with size, but it can be steel of about 0.304 mm (12 gage) or cast iron of an appropriate thickness. The containers are filled with the coal, preferably as individual briquettes of a shape and volume corresponding to the inner shape and volume of the container, the lids using mechanical devices, such as interlocking lugs, or by riveting or spot welding or by others suitable devices are attached, but in each case vents

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released for the escape of volatile gases therefrom will. If the containers are spherical, they can be made from two hemispherical shells of a selected size are made, which coal in the form of a round briquette, for example from 0.23 to Contain just over 0.9-1 kg (1/2 to just over 2 pounds) in weight. The outlet openings can be openings in the container walls or they can be cracks between the Form the lid and the rest of the container or between the welds.

It is understood that a briquette, which is essentially in Size and shape corresponds to the inner space of the container, exerts a considerable pressure on the walls of the container, which is caused by the swelling of the coal Withstand the urge to expand when the coal is down is subjected to increasing heat gradients in the upper zone of the furnace. The resulting compression forces result in a good, solid coke that takes the load off carries after the containers melt away.

The metal containers are sufficiently rigid to withstand the furnace load in the upper zone and then, After the hard coke is formed, this coke will be his Contribute to the load after the metal containers have melted in the lower zone, in which the coke

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the same punctures as in a standard fan shaft furnace exercises.

In the attached drawings Fig.l shows a schematic view of a fan shaft furnace, in v / elcher in the frame the tapping hole 10 for the melted Lisen, above the slag branch 12 and above the Kinführungstutzen I ² I for the introduction of a gas that maintains the combustion, for example oxygen-enriched air, in which rest is indicated. At 16 inlets for the introduction of preheated secondary air are shown. The portion of the furnace above the inlets 16 is referred to as the upper heating zone and the portion of the furnace above the molten slag is referred to as the lower reduction zone.

Pig.2 is a flow chart in which the reactions and Reaction sequences during a combined coking process in the upper area and an ore reduction process in the lower area Area in accordance with the present invention is indicated in a registering manner.

The jacketed coal is introduced into the furnace top as part of the charge: which comprises ore pellets and sinter. Any CO or H ₂ entering the resting area as part of the rising gases as a result of the oxygen wind

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^ inführungsstutzen IH enters upwardly koninit and in the upper zone ues furnace burns along this zone HDT hydrocarbons and others from the coal in the vessels aborted other volatile compounds under neaktion! .. it the secondary air such that the stack gases a very high content of C0 _? and HG iu relationship to theirs. Have content of CO and H ₂ . '.''hen the top gas virtually free of irgendvfelchen flammable gases and as a result of Viax-i.ieaust exchange with the Singangsb it chi ckung on lower ^ Etruscan-temperature is brought, a Warmeruck- ■ _o ewirmünö iri.cien conventional ovens superfluous, which results in further savings in terms of equipment and operating costs.

The volatiles are expelled from the coal at initial temperatures of about 371 C (700 F) and this expulsion is ^{completed at about i20ft ° C (220O 0} P).

Just as the old coal has sunk beneath the inlets Io, freed from its volatile substances and now coked, the containers have by then melted from the coke and the coke then formed reaches the lower part of the furnace, with its surfaces now like this are openly exposed that the solid carbon in it with the vind blown in at Ik to maintain the reduction

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conditions for ore reduction as in the standard fan shaft furnace. The wind can be heated by separate, stationary Vorviärner using coal, oil or gas and if necessary with oxygen enrichment.

Insofar as the supply of coated charcoal to the gout of the fan shaft furnace replaces the supply of pre-formed coke, it represents a corresponding saving in investment costs for a coke oven and its operating and maintenance costs. Even if it is in some cases it is to be expected that the entire fuel consumption of the fan shaft furnace is only partially covered by coated charcoal, with the remainder being the preformed one currently in use Coke is, however, any decrease in coke requirements for steelmaking will be more than welcome, in view of the limited service life of many coke ovens, which otherwise have to be rebuilt or replaced soon.

In addition, it is to be expected that certain types of coal, which are currently not regarded as coking coal and therefore cost less, wholly or partly in the containers of the present invention and because of the higher pressure conditions in the fan shaft furnace over the conventional coke ovens satisfactorily coked therein can be. ·

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The numerical values given in the present description are for explanation purposes only and may vary depending on can be varied according to the prevailing conditions »

009 882/108 $

Claims (2)

Claim e 1. Method of replacing some or all of the coke required for one in a fan shaft furnace Iron ore reduction process carried out with an upper heating zone and a lower reduction zone, characterized in that that coal is introduced into the top of the furnace as part of the descending charge, intended for the shooter from the gases rising from the lower reduction zone through the upper zone into gas-permeable, rigid, fusible ones Enclosed is the coal in the containers to drive off the volatile content from the container Coal in the gas-permeable container is heated in the ascending gas flow and the coal in the one in the upper zone converts the prevailing pressure into coke, a combustion sustaining gas near the bottom of the upper zone of the furnace in order to volatilize in the furnace the volatile expelled from the coal in the containers during coking Burn connections and so heat the upper zone and after converting the coal into coke and Sinking the same into the lower zone the container to expose the coke melts around the coke through the lower zone Zone to maintain a reducing atmosphere in the same to expose rising, heated gases ". 009 882/166 $ - 11 - 2. The method according to claim 1, characterized in that the coal in the form: is present from briquettes, which in the Wes ent borrowed the same size and shape as the Innenrauui cos mentioned üehälters has to the coal eini .. • .'iaerstanu _ , e _{: j} en to suspend their expansion if they, as well as they uci. downwardly rising liitze-öradients of the Ofeiu are subject to Viira, dasu nei _o t, anzuscawellen, woi. oiii taster coke produced v / ird. BADOB.G.NAL 009682/1665 ^bath ORIGINAL L e r s e ι t e COPY