Background technology
Pulverized coal injection in blast furnace is the key link of ironmaking system composition optimizes, is one of three great technological lines of China's Iron And Steel Industry development, also is the megatrend of domestic and international blast furnace technology development.Improve the coal powder injection ratio, not only can alleviate the situation of China's coking coal shortage, and can reduce the pollution of process of coking to environment, simultaneously, can also reduce ironmaking production cost (1 ton of coal dust of every spray can produce the economic benefit of 500-600 unit) by a relatively large margin, improve the market competitiveness of ironmaking enterprise, realize the environmental friendliness of production process.So iron and steel enterprise is all making great efforts to improve the coal powder injection ratio, but excessive coal powder injection meeting causes blast wandering, because pulverized coal injection in blast furnace enters belly pipe by spray gun, through mixing with high speed hot blast stream, by heated at high speed, moisture evaporation, volatile matter is separated out, must rapid decomposition combustion in the air port, otherwise the unburned carbon powder can influence blast furnace permeability with the speed of millisecond meter, therefore to improve injecting coal quantity and will take measures improving on burning of coal characteristic and the rate of combustion.A large amount of reported literatures show, add metallic element or its esters, particularly basic metal such as K, Na or its esters in fire coal, can play the effect of catalyzed reaction.These metallic elements have mainly served as the active carrier of oxygen in the burning of coal process, Sauerstoffatom is constantly passed to carbon atom, and this process is direct more much easier with the oxygen reaction than carbon, has quickened the oxidising process of coal.These metal ions can also embed the carbon intracell simultaneously, and the electronic configuration of carbon surface is changed, and as electron donor, by the migration of electric charge, make the oxidizing fire reaction of carbon obtain quickening.Therefore these metallic elements particularly K, Na can quicken the reaction process of carbon and oxygen, make catching fire in advance of carbon, the rate of combustion raising.Salting on firewood carbon (NaCl) adds Ba (NO in honeycomb briquet lighting and barbecue coal briquette
3)
2, NaNO
3, KClO
3, KMnO
4, coal firing boiler adds the chemical catalysis ignition dope in coal, all be utilizing basic metal such as K, Na or its esters to reduce the point of ignition of coal as oxygenant and catalyzer, improving volatile matter and separate out productive rate, combustionvelocity and efficiency of combustion.The also available chemical additive of pulverized coal injection in blast furnace improves the combustionvelocity and the efficiency of combustion of coal powder injection, thereby improve the coal powder injection ratio, but the pulverized coal injection additive can not contain basic metal such as K, Na, these can promote the molten damage reaction of coke to take place at the blast furnace circulating enrichment to bringing into of blast furnace ironmaking harmful element, destroy the skeleton supporting role, infiltrate the furnace lining slit, shorten the life-span of furnace lining, also can be in blast furnace dross destroy the reasonable distribution and the utilization ratio of blast furnace gas, cause the blast wandering coke ratio to increase.Therefore the pulverized coal injection in blast furnace chemical additive can not contain basic metal such as K, Na.
Summary of the invention
The object of the present invention is to provide a kind of basic metal such as K, Na that do not contain, the chemical additive that pulverized coal injection in blast furnace is had catalysis, oxidation, activation, performance such as combustion-supporting, be used for improving the combustioncharacteristics of coal injection, improve the combustionvelocity and the efficiency of combustion of coal injection.Contain passivator in the additive of the present invention, be used for the reactive behavior of passivation blast-furnace coke, strengthen the supporting role of coke skeleton, suppress the low temperature reduction degradation of blast furnace top iron-containing charge.
A kind of chemical additive for pulverized coal injection in blast furnace, composition comprise oxygenant, catalyzer, ignition dope, passivator, mix according to a conventional method.Active principle content (weight percent) is: oxygenant 20-40%; Catalyzer 15-25%; Ignition dope 20-50%; Passivator 5-15%.The best composition of additive is oxygenant 28-32%; Catalyzer 18-22%; Ignition dope 43-47%; Passivator 3-7%.
The coal powder injection additive mechanism of action
Additive is selected BaMnO for use
4, Ca (NO
3)
2, Ce (NO
3)
3Make oxygenant, decompose release O in the differing temps stage
2, promote coal-fired oxidizing reaction speed, and its degradation production (BaO, CaO, Ce
2O
3, MnO) be again coal combustion catalyst, further excite the reactive behavior of each component in the coal, quicken the burning of coal process.BaMnO
4, Ca (NO
3)
2, Ce (NO
3)
3Make oxygenant, can select wherein a kind ofly arbitrarily, also can select wherein the mixture of two kinds or three kinds to mix, the ratio of each composition is unrestricted in the mixture.
Select (C for use in the coal powder injection additive
5H
5)
2Fe has further excited the reactive behavior of each component in the coal as active catalyst.
Additive is selected ferrocene [(C for use
5H
5)
2Fe] more superior to the catalyst combustion reaction of coal as catalyzer than basic metal such as K, Na or its esters.Ferrocene is a kind of organometallics, various fuel there is very strong combustion supporting catalytic performance, in space industry, be used as the burningrate catalyst of rocket propellant, its principle is that ferrocene is when burning together with various fuel, decomposite the active iron ion, this active iron ion and airborne oxygen intense reaction generate α-Fe
2O
3Bioactive molecule, α-Fe
2O
3Be the combustion supporting catalyst of various fuel, can accelerate the combustionvelocity of fuel and make its burning fully.In addition, catalyzer can add 90-10% Manganse Dioxide [MnO
2] substitute the ferrocene of corresponding section.Contain metallic elements such as Ba, Ca, Ce, Mn, Fe in the coal powder injection additive fire coal is also played obvious catalysis, the active carrier that in the burning of coal process, has mainly served as oxygen, promote that oxygen spreads to carbon surface from gas phase, thereby reduced fixed carbon surface kindling temperature, also promote separating out of volatile matter in the coal simultaneously, improve the activity on fixed carbon surface, promoted the carrying out of gas-solid phase combustion reactions.Catalyzer in the additive also at the composition that changes volatile matter, reduces the kindling temperature of coal homogeneous combustion when improving coal-fired volatile producibility, thereby quickens the burning of coal process.Simultaneously catalyzer has also quickened the scission reaction of coal itself, makes the coal-tar middle oil and crude benzol of coal be easy to decompose, and causes the increase of gas and lower molecular weight hydrocarbon polymer output, therefore, the coal powder ignition point temperature that is added with the coal powder injection additive reduces, and combustionvelocity is accelerated, and efficiency of combustion improves.
Additive select for use waste old or plastics after the powder process of jet spray cooling as ignition dope, the heat release and produce section H of at high temperature burning
2, combustion-supporting effect is played in burning of coal, and H
2Or the desirable reductive agent of ironmaking.
Additive is selected the CoCl with stable chemical property for use
2Or InCl
3Or CoCl
2With InCl
3Mixture be passivator, CoCl
2With InCl
3Mixture ratio unrestricted.This passivator high temperature gasifies to be regardless of down and separates, and rise to the blast furnace cold zone with blast furnace gas and solidify, adhere to iron-containing charge and coke surface, drop to the high-temperature zone rising of gasifying again with furnace charge again, at the blast furnace circulating enrichment, even dispersion sticks to coke and iron-containing charge surface, fills the pore of coke and iron-containing charge, and molten damage and the gasification combustion reactions of coke at cold zone decayed.Simultaneously, in composition silicate and acid ferric complex salt crystal or the lattice, improved the mechanical property and the intensity of composition silicate, and suppressed Fe when passivator embeds the iron-containing charge low-temperature reduction with calking or the mode of subrogating
2O
3Be reduced into Fe
3O
4The time crystal conversion and the efflorescence of volumetric expansion.
Additive has catalysis, activation, oxidation, combustion-supporting performance to coal injection, can obviously improve the combustioncharacteristics of coal injection, reduce kindling temperature, improve volatile matter and separate out productive rate, combustionvelocity and efficiency of combustion, substantially prevent 500 ℃ of low temperature reduction degradations of iron-containing charge, significantly reduce the gasification, and combustion speed of coke, strengthen the skeleton supporting role, improve blast furnace permeability, promote furnace condition anterograde.
In fire coal, add 1.5% coal powder injection additive, can reduce by 11 ℃ of coal-fired ignition temperatures, improve volatile matter and separate out productive rate 23.38%, improve efficiency of combustion 18.52%, low-temperature reduction intensity index (RDI during 500 ℃ in agglomerate
+ 6.3) improving 23.10%, coke reactivity (CRI) reduces by 11.23%, and post-reaction strength (CSR) improves 10.57%.
If China's iron-smelting blast furnace is all with addition of this kind additive, burnt about more than 700 ten thousand tons of Nian Kejie, the blast furnace ironmaking cost can significantly reduce, and can reduce the input of coke production simultaneously, reduces environmental pollution.
Embodiment
Choose four kinds of prescriptions and test the influence that point of ignition, ignition delay time, volatile matter to coal are separated out productive rate, efficiency of combustion respectively, test the passivation effect of its STRENGTH ON COKE and iron-containing charge simultaneously, further instruction of the present invention.
Embodiment 1
Active principle content (weight percent) is: oxygenant 28% (Rosensthiel's green 50%, nitrocalcite 50%); Catalyzer 21% (ferrocene 30%, Manganse Dioxide 70%); Ignition dope 47% (waste rubber powder); Passivator 4% (cobalt chloride).
Embodiment 2
Active principle content (weight percent) is: oxygenant 30% (Rosensthiel's green 30%, nitrocalcite 30%, cerous nitrate 40%); Catalyzer 20% (ferrocene 50%, Manganse Dioxide 50%); Ignition dope 45% (waste rubber powder); Passivator 5% (cobalt chloride 50%, Indium-111 chloride 50%).
Embodiment 3
Active principle content (weight percent) is: oxygenant 32% (Rosensthiel's green 60%, cerous nitrate 40%); Catalyzer 22% (ferrocene 40%, Manganse Dioxide 60%); Ignition dope 43% (synthetic resin moulding compound); Passivator 3% (Indium-111 chloride).
Embodiment 4
Active principle content (weight percent) is: oxygenant 31% (calcium manganate 60%, cerous nitrate 40%); Catalyzer 18% (ferrocene 70%, Manganse Dioxide 30%); Ignition dope 45% (synthetic resin moulding compound); Passivator 6% (cobalt chloride 50%, Indium-111 chloride 50%).
Standard method of test according to the coal dust firing characteristic is tested embodiment of the invention 1-4, with additive press the coal injection amount 1.5% with addition of in coal dust, test it separates out productive rate, efficiency of combustion to igniting temperature of pulverized-coal, volatile matter influence.This test is adopted and is mixed coal (bituminous coal and hard coal respectively account for 50%).Simultaneously according to the effect of GB/T 13242-91 standard method test coal powder injection additive to inhibition low temperature reduction degradation under 500 ℃ of temperature of agglomerate.According to the measuring method of GB/T 2006-94 metallurgical coke physical strength, the active passivation effect of test coal powder injection additive STRENGTH ON COKE pyroreaction.Test result to the coal dust firing characteristic sees Table 1, and STRENGTH ON COKE influence reactive and post-reaction strength sees Table 2, and the influence of 500 ℃ of reduction degradation performances of iron-containing charge is seen Table 3.
Table 1: the coal powder injection additive is to the influence of mixed coal combustioncharacteristics
Embodiment | With addition of ratio (%) | Point of ignition (℃) | Volatile matter eduction rate (%) | Efficiency of combustion function (static %) |
0 | 1.5 | 393 | 7.7 | 35.1 |
1 | 1.5 | 386 | 8.5 | 39.5 |
2 | 1.5 | 382 | 9.5 | 41.6 |
3 | 1.5 | 385 | 8.9 | 38.3 |
4 | 1.5 | 389 | 8.6 | 39.1 |
Table 2: the coal powder injection additive is to the influence of 500 ℃ of reduction degradation performances of agglomerate
Embodiment | Reduction intensity index RDI
+6.3 | Reduction degradation index RDI
+3.15 | Reduction abrasion index RDI
-0.5 |
0 | 39.4 | 65.2 | 12 |
1 | 45.6 | 79.6 | 4.5 |
2 | 48.5 | 88.6 | 2.4 |
3 | 43.7 | 81.5 | 3.6 |
4 | 44.2 | 82.3 | 4.7 |
Table 3: the influence of coal powder injection additive STRENGTH ON COKE reactivity and post-reaction strength
Embodiment | Coke reactivity (CRI%) | Postreaction strength of coke (CSR%) |
0 | 28.5 | 63.4 |
1 | 26.4 | 66.5 |
2 | 25.3 | 70.1 |
3 | 27.6 | 67.7 |
4 | 26.9 | 69.2 |
By test-results as can be seen, coal injection adds coal powder injection additive of the present invention can reduce by 11 ℃ of coal-fired kindling temperatures, improves volatile matter and separates out productive rate 23.38%, improves efficiency of combustion 18.52%, low-temperature reduction intensity index (RDI during 500 ℃ in agglomerate
+ 6.3) improving 23.10%, coke reactivity (CRI) reduces by 11.23%, and post-reaction strength (CSR) improves 10.57%.