Method of operating a blast furnace

Claim 2

IN A METHOD OF OPERATING A BLASTFURNACE WITH COKE AS THE PRINCIPAL FUEL AND WITH A CARBON OR HYDROCARBON-CONTAINING AUXILIARY FUEL, SUCH AS PETROLEUM, PETROLEUM PRODUCTS NATURAL GAS, COKE OVEN GAS OR COAL DUST, WHEREIN THE COLE, IN CONVENTIONAL MANNER IS CHARGED THROUGH THE TOP OF THE FURNACE WHILE THE AUXILIARY FUEL IS HEATED AND BROKEN DOWN IN A REACTION SPACE LOCATED OUTSIDE THE HEARTH OF THE FURNACE AND THE DECOMPOSITION PRODUCTS OF THE AUXILIARY FUEL THUS OBTAINED ARE INTRODUCED INTO THE HEARTH THROUGH TUYERE MEANS, THE HOT BLAST FOR THE OPERATION OF THE FURNACE BEING CARRIED BY BLOW PIPE MEANS ADJACENT TO AND COMMUNICATING WITH SAID TUYERE MEANS AND BEING INTRODUCED INTO THE FURNACE THROUGH SAID TUYERE MEANS, THE IMPROVEMENT WHICH COMPRISES THAT AID AUXILIARY FUEL IS DECOMPOSED AND INCOMPLETELY BURNT IN SAID REACTION SPACE AND THE INCOMPLETELY BURNT DECOMPOSITION PRODUCTS

Claim 3

The improvement as claimed in claim 1, wherein the quantity ratio of auxiliary fuel to oxygen in the reaction space is such that the decomposition products exiting from said reaction space contain a large proportion of soot.

Claim 4

The improvement as claimed in claim 1, wherein pure oxygen is introduced into said reaction space.

Claim 5

The improvement of claim 1, wherein said blow pipe means defines at least three separate flow passages, said hot blast flowing through each of said flow passages, while auxiliary fuel is charged to less than all said flow passages.

Claim 6

The improvement as claimed in claim 1, wherein said hot blast is divided in said blow pipe means into first and second streams of which one stream is introduced into the hearth of the furnace through said tuyere means while the other stream, after separation from said one stream, is contacted in said reaction space with said auxiliary fuel to break down said auxiliary fuel, said other stream constituting said reaction space and said auxiliary flow, whereafter the decomposition products thus formed and said other stream are united with said one stream at a location which is closely adjacent to the entry point into the hearth of the furnace.

Claim 7

The improvement as claimed in claim 5, wherein the auxiliary fuel is introduced into said other stream in a direction perpendicular or opposite to the flow direction of said other stream of the hot blast.

Claim 8

The improvement as claimed in claim 1, wherein said blow pipe means defines first and second separated flow passages, said first flow passage coaxially surrounding said second flow passage, one of said flow passages defining said reaction space and said auxiliary flow, said auxiliary fuel being introduced into said one flow passage and the hot blAst flowing through both of said flow passages.

Claim 9

The improvement of claim 7, wherein said auxiliary fuel is introduced into said second flow passage.

Claim 10

The improvement of claim 7, wherein said flow passages are united adjacent said tuyere means.

Claim 11

The improvement of claim 7, wherein the auxiliary fuel is introduced into said first flow passage.

Claim 12

In a method of operating a blastfurnace with coke as the principal fuel and with a carbon- or hydrocarbon-containing auxiliary fuel, such as petroleum, petroleum products, natural gas, coke oven gas or coal dust, wherein the coke, in conventional manner, is charged through the top of the furnace while the auxiliary fuel is heated and broken down in a reaction space located outside the hearth of the furnace and the decomposition products of the auxiliary fuel thus obtained are introduced into the hearth through tuyere means, the hot blast for the operation of the furnace being carried by blow pipe means adjacent to and communicating with said tuyere means and being introduced into the furnace through said tuyere means, the improvement which comprises that said reaction space surrounds and communicates with said blow pipe means, said decomposition products of the auxiliary fuel after formation in said reaction space and after exiting from said reaction space, being directly introduced into said blow pipe means where the decomposition products intermingle with the hot blast flowing through said blow pipe means, said hot blast and decomposition products thereafter flowing into the hearth through said tuyere means.

Claim 13

In a method of operating a blastfurnace with coke as the principal fuel and with a carbon- or hydrocarbon-containing auxiliary fuel, such as petroleum, petroleum products, natural gas, coke oven gas or coal dust, wherein the coke, in conventional manner, is charged through the top of the furnace while the auxiliary fuel is heated and broken down in a reaction space located outside the hearth of the furnace and the decomposition products of the auxiliary fuel thus obtained are introduced into the hearth through tuyere means, the hot blast for the operation of the furnace being carried by blow pipe means adjacent to and communicating with said tuyere means and being introduced into the furnace through said tuyere means, the improvement which comprises that said reaction space surrounds and communicates with said blow pipe means, said decomposition products of the auxiliary fuel after formation in said reaction space and after exiting from said reaction space, being directly introduced into said blow pipe means where the decomposition products intermingle with the hot blast flowing through said blow pipe means, said hot blast and decomposition products thereafter flowing into the hearth through said tuyere means.

Claim 14

The improvement of claim 11, wherein said decomposition products enter said blow pipe means in a direction which is inclined relative to the flow direction of hot blast through said blow pipe means.

Claim 15

The improvement of claim 11, wherein said hot blast and said decomposition products flow towards said tuyere means through a zone having a cross-section which is narrower than the cross-section of the flow space defined by said blow pipe means.

Claim 16

In a method of operating a blast-furnace with coke as the principal fuel and with a carbon- or hydro-carbon-containing auxiliary fuel, such as petroleum, petroleum products, natural gas, coke oven gas or coal dust, wherein the coke, in conventional manner, is charged through the top of the furnace while the auxiliary fuel is heated and broken down outside the hearth of the furnace and the decomposition products of the auxiliary fuel thus obtained are introduced into the hearth through tuyere means, the hot blast for the operation of the furnace being carried by blow pipe means adjacent to and communicating with said tuyere means and being introduced into the furnace through said tuyere means, the improvement which comprises at least partially breaking down said auxiliary fuel in a reaction zone closely adjacent said tuyere means and conveying the decomposition products thus obtained into the flow passage of said blow pipe means for contact with the hot blast flowing therethrough, said reaction zone surrounding and communicating with said flow passage.

Claim 17

In a method of operating a blast-furnace with coke as the principal fuel and with a carbon- or hydro-carbon-containing auxiliary fuel, such as petroleum, petroleum products, natural gas, coke oven gas or coal dust, wherein the coke, in conventional manner, is charged through the top of the furnace while the auxiliary fuel is heated and broken down outside the hearth of the furnace and the decomposition products of the auxiliary fuel thus obtained are introduced into the hearth through tuyere means, the hot blast for the operation of the furnace being carried by blow pipe means adjacent to and communicating with said tuyere means and being introduced into the furnace through said tuyere means, the improvement which comprises at least partially breaking down said auxiliary fuel in a reaction zone closely adjacent said tuyere means and conveying the decomposition products thus obtained into the flow passage of said blow pipe means for contact with the hot blast flowing therethrough, said reaction zone surrounding and communicating with said flow passage.

Claim 18

In a method of operating a blast-furnace with coke as the principal fuel and with a carbon- or hydrocarbon-containing auxiliary fuel, such as petroleum, petroleum products, natural gas, coke oven gas or coal dust, wherein the coke, in conventional manner, is charged through the top of the furnace while the auxiliary fuel is heated and broken down in a reaction space located outside the hearth of the furnace and the decomposition products of the auxiliary fuel thus obtained are introduced into the hearth through tuyere means, the hot blast for the operation of the furnace being carried by blow pipe means adjacent to and communicating with said tuyere means and being introduced into the furnace through said tuyere means, the improvement which comprises that said decomposition products of the auxiliary fuel, after exiting from said reaction space, are directly introdUced into said blow pipe means or said tuyere means, said blow pipe means defining first and second separated flow passages, said first flow passage coaxially surrounding said second flow passage, one of said flow passages defining said reaction space, said auxiliary fuel being introduced into said first flow passage and the hot blast flowing through both of said flow passages.

Claim 19

In a method of operating a blast-furnace with coke as the principal fuel and with a carbon- or hydrocarbon-containing auxiliary fuel, such as petroleum, petroleum products, natural gas, coke oven gas or coal dust, wherein the coke, in conventional manner, is charged through the top of the furnace while the auxiliary fuel is heated and broken down in a reaction space located outside the hearth of the furnace and the decomposition products of the auxiliary fuel thus obtained are introduced into the hearth through tuyere means, the hot blast for the operation of the furnace being carried by blow pipe means adjacent to and communicating with said tuyere means and being introduced into the furnace through said tuyere means, the improvement which comprises that said decomposition products of the auxiliary fuel, after exiting from said reaction space, are directly introdUced into said blow pipe means or said tuyere means, said blow pipe means defining first and second separated flow passages, said first flow passage coaxially surrounding said second flow passage, one of said flow passages defining said reaction space, said auxiliary fuel being introduced into said first flow passage and the hot blast flowing through both of said flow passages.

Claim 20

In a method of operating a blast-furnace with coke as the principal fuel and with a carbon- or hydrocarbon-containing auxiliary fuel, such as petroleum, petroleum products, natural gas, coke oven gas or coal dust, wherein the coke, in conventional manner, is charged through the top of the furnace while the auxiliary fuel is heated and broken down outside the hearth of the furnace and the decomposition products of the auxiliary fuel thus obtained are introduced into the hearth through tuyere means, the hot blast for the operation of the furnace being carried by blow pipe means adjacent to and communicating with said tuyere means and being introduced into the furnace through said tuyere means, the improvement which comprises at least partially breaking down and incompletely burning said auxiliary fuel in a reaction zone closely adjacent said tuyere means and conveying the decomposition products thus obtained into the flow passage of said blow pipe means in the form of an auxiliary flow for contact with the hot blast flowing therethrough, said auxiliary flow intermingling with said hot blast just prior to the discharge of the hot blast into the furnace through said tuyere means.

Claim 21

In a method of operating a blast-furnace with coke as the principal fuel and with a carbon- or hydrocarbon-containing auxiliary fuel, such as petroleum, petroleum products, natural gas, coke oven gas or coal dust, wherein the coke, in conventional manner, is charged through the top of the furnace while the auxiliary fuel is heated and broken down outside the hearth of the furnace and the decomposition products of the auxiliary fuel thus obtained are introduced into the hearth through tuyere means, the hot blast for the operation of the furnace being carried by blow pipe means adjacent to and communicating with said tuyere means and being introduced into the furnace through said tuyere means, the improvement which comprises at least partially breaking down and incompletely burning said auxiliary fuel in a reaction zone closely adjacent said tuyere means and conveying the decomposition products thus obtained into the flow passage of said blow pipe means in the form of an auxiliary flow for contact with the hot blast flowing therethrough, said auxiliary flow intermingling with said hot blast just prior to the discharge of the hot blast into the furnace through said tuyere means.

Claim 22

The improvement of claim 16, wherein said flow passage defines first and second passage-ways, one of said passage-ways constituting said reaction zone and auxiliary flow, said auxiliary fuel being introduced into said one passage-way while said hot blast is introduced into both of said passage-ways.