CN104745757B - A kind of microwave fuel combined heat formula coal-based direct reduction method and rotary hearth furnace - Google Patents
A kind of microwave fuel combined heat formula coal-based direct reduction method and rotary hearth furnace Download PDFInfo
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- CN104745757B CN104745757B CN201310740483.4A CN201310740483A CN104745757B CN 104745757 B CN104745757 B CN 104745757B CN 201310740483 A CN201310740483 A CN 201310740483A CN 104745757 B CN104745757 B CN 104745757B
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Abstract
The invention discloses a kind of microwave fuel combined heat formula coal-based direct reduction method and rotary hearth furnace, the method is：Material enters reduction operation by drying and preheating, and material is reduced first with the mode of fuel combustion, and material is further reduced by the way of microwave then；Metal oxide be reduced to metal needed for the fixed carbon that comes from material of reducing agent.The rotary hearth furnace is the equipment based on the above method.The present invention has the advantages that simple structure, with low cost, degree of metalization high, easy realization and popularization and application.
Description
Technical field
Present invention relates generally to coal-based direct reduction rotary hearth furnace field, the microwave combustion of a kind of use fuel and microwave is refered in particular to
Material combined heat formula coal-based direct reduction method and the rotary hearth furnace based on the method.
Background technology
Coal-based direct reduction rotary hearth furnace technology is with coal as reducing agent, by the metal in ore materials under non-soft heat situation
Oxide is reduced into a kind of method of metal.The method does not rely on coking coal resource, compared to traditional Steel Production Flow Chart, can be significantly
The discharge of pollutant is reduced, its product can replace steel scrap as the raw material of electric furnace smelting high-quality steel.Therefore, the technique market prospects
It is wide, it is one of Main way of following smelting iron and steel development.
The conventional method of direct-reduction production has gas-based shaft kiln method, coal base grate kiln method, coal base rotary hearth furnace method.
Gas-based shaft kiln method is with natural gas as reducing agent, if being used for the deficient and expensive area of natural gas resource, direct-reduction production
High cost.In addition the technological investment is excessive, and equipment performance requirement is higher, and popularization receives extreme influence.Coal base drying grate-return
Rotary kiln method has very big attraction to the area that coal resource enriches with coal as reducing agent, but the technology will to temperature control precision
Ask higher, it is relatively low easily to tie kiln, operating rate in production, cause often stopping production, its promotion and application to stay cool.Coal base turns
Bottom stove Direct Reduction Technology is because of rotary hearth furnace simple in equipment, maximization difficulty is small, do not tie kiln, plant maintenance is simple, investment phase
To it is less the advantages of, be widely used in the industries such as metallurgical and building materials.It is used for heating the rotary heating furnace of steel billet such as steel plant, its
Structure is close with rotary hearth furnace, simply thermal regulation and operation principle difference.
Above advantage based on rotary hearth furnace, recent domestic for rotary hearth furnace treatment steel plant zinc-containing dust, separate iron,
Zinc, lead element；Treatment loess nickel minerals, extracts nickel metal；Treatment vanadium titano-magnetite, extracting vanadium, titanium valuable metal etc. has been carried out extensively
General research, and achieve some breakthrough progress.Unanimously think that rotary hearth furnace method is that existing treatment steel plant contain zinc in metallurgical boundary
The preferable method of dust, can efficiently separate iron, zinc, the lead and other elements in dust, zinc enrichment is solved well and causes blast furnace
Dross, shortens the problem of the life of the blast furnace, solves the problems, such as that dust stores up a large amount of land occupations, pollution environment, solves dust
Middle valuable metal is difficult to the problem for recycling.But such as resultant metal rate is still suffered from rotary hearth furnace process implementation process
Low, the product quality crucial technical problem such as uneven, if problem above can be captured, its development prospect will be more wide.
As depicted in figs. 1 and 2, the existing rotary hearth furnace top view and expanded view respectively containing cooling section；Such as Fig. 3 and Fig. 4 institutes
Show, existing rotary hearth furnace top view and expanded view respectively without cooling section.The rotary hearth furnace technology be using the burning fuel of burner 1 come
Carbon containing material 3 on heating siege 2.Main 4 groups of the siege 2 and top bonnet by rotating of this conventional direct-reduction rotary hearth furnace
Into.Bonnet 4 is covered on the siege 2 of rotation, is sealed by way of liquid-tight envelope or sand seal between bonnet 4 and siege 2, to prevent stove
Inside and outside air-flow is fled and heat losses.Siege 2 according to its operation function be in turn divided into cloth section 101, drying and preheating section 102,
Fuel combustion reduction section 103, cooling section 105（Fig. 1）, discharge zone 106.Cloth section 101 and drying and preheating section 102 between and arrange
Envelope wall 7 is equipped between material section 106 and cooling section 105, and between cloth section 101 and discharge zone 106.As heating plant
Burner 1 be provided on the inside and outside side wall of the bonnet 4 of fuel combustion reduction section 103, the burning fuel of burner 1 produce high temperature cigarette
Gas, the heat needed for meeting direct reduction reactor temperature, minimum temperature is 800 DEG C in stove, and maximum temperature is up to 1300 DEG C or higher.
The flue gas stream direction of motion that stove fuel combustion is produced is opposite with the traffic direction of material 3（The traffic direction of material 3 and siege 2
Such as direction shown in solid in Fig. 1, Fig. 3；Flue gas stream traffic direction such as Fig. 1, direction shown in dotted lines in Figure 3）, finally from setting
The chimney 6 near cloth section side at the top of the bonnet of drying and preheating section 102 is put to discharge.Material 3（It is commonly called as green-ball）By material distributing machine 8
Equably it is laid on the siege 2 of rotary hearth furnace rotation, by after the processes such as drying, preheating, reduction, moisture, Yi Hui in material 3
Hair part is removed, and metal oxide is reduced into metal by the fixed carbon in material 3.The high temperature reduction product of acquisition is by unloader 10
Discharge rotary hearth furnace（Such as Fig. 3）, or cooled down through being covered with the cooling section 105 of cooling water pipe 9（Such as Fig. 1）Afterwards, discharged by unloader 10 and turned
Bottom stove, molten point of heating is carried out into cooler 11 or into mineral hot furnace.
The subject matter that routine direct-reduction rotary hearth furnace is present has：
1）Due to being laid on the required heat of the drying of material 3 rotated on siege 2, preheating, reduction both from being located at
The radiant heat of the high-temperature flue gas produced by the burning fuel of burner 1 on the inside and outside side wall of bonnet 4 of fuel combustion reduction section 103, and
Material 3 has certain thickness again, so that top material 3 is heated soon, bottom material 3 is heated slowly.Material 3 is thicker, this
Thermograde is more obvious.Meanwhile, after the temperature of only material 3 reaches certain value, reduction reaction just can fast and stable carry out.With
Upper both sides reason generates yield and quality of the rotary hearth furnace to its product（Mainly percent reduction）The contradiction taken into account is difficult to, i.e.,
The timing of thickness of feed layer one, residence time of the yield with material 3 in stove is inversely proportional, and percent reduction and stop of the material 3 in stove
Time is directly proportional.A series of problems, such as this contradiction causes investment, operating cost, energy consumption, economy, product quality.It is just existing
Have from the point of view of some the rotary hearth furnace production instances for putting into operation, the counter investment of its unit capacity is larger, to ensure product
Degree of metalization meets the requirement of electric arc furnace smelting, and production capacity need to be greatly reduced, and this makes it difficult for enterprise to be received.Just because of this,
So that numerous enterprises give up the pursuit of high metal rate and ensure certain disposal ability, cause the resultant metal rate come out of the stove compared with
Low, its product can only be used as blast furnace burden, and less than 3 millimeters granular materials can only return to sintering agglomeration again.According to existing production
Data statistics, the degree of metalization of product is below 70%, and more than 3 millimeters yield rates only have 50% or so, and zinc recovery only has 80%.
As can be seen here, conventional rotary hearth furnace technology is also clearly present numerous problem demanding prompt solutions, otherwise by danger on the verge of being replaced.
2）Another major issue that conventional rotary hearth furnace technology is present is, even if it is sufficiently long to allow material 3 to be stopped in stove
Time, it is ensured that the metal oxide of lower floor's material 3 obtains sufficiently high percent reduction, but big due to containing in the flue gas of fuel combustion
The CO of amount2The gas of class oxidizing atmosphere, can be by as-reduced metal re-oxidation in top material 3.This is also existing to turn bottom
Under stove thermal regulation, resultant metal rate another reason not high.Further investigation is found, is difficult to solve using conventional heating means
Certainly problem above, if taking the back segment of fuel combustion reduction section 103 not lay the measure of burner, to reduce the oxidisability in flue gas
Atmosphere, then reduction heat absorption and body of heater radiating will make furnace temperature rapid decrease, cause resultant metal rate still cannot further improve.Cause
This, there is fatal defect in conventional rotary hearth furnace technology, it is impossible to realize the double targets high of yield, degree of metalization in thermal regulation.
3）In order to provide enough heats, improve resultant metal rate, often require that conventional rotary hearth furnace reduction section temperature is high
In 1300 DEG C.In rotation process, constantly the temperature difference impact between experience high temperature reduction section and sub-cooled section, causes siege 2
Siege reduced lifetime.
There is practitioner to propose a kind of direct-reduction rotary hearth furnace using full microwave mode, as shown in Figure 5 and Figure 6, it is utilized
One or more microwave catheters, microwave 12 are imported in furnace chamber from microwave generator, by the intensity for controlling microwave
Grade, makes carbon containing ferriferous oxide material 3 be heated to moderate moisture and carries out autoreduction, it is to avoid the reduction of phosphorus, sulphur and silica.
But, the method has no the report of related further investigation and practice at present.By the in-depth analysis to which, lead
Causing its subject matter for being difficult to put into practice has：
1）When material 3 is less than certain temperature, the coupling between microwave 12 and material 3 is weaker, microwave 12
Radiant heating speed to metal oxide material 3 is slower, and the thermal efficiency is very low.But at high temperature, not only microwave itself radiation
Ability is strengthened, and can strengthen the activity of metal oxide, accelerates the gasification reaction of fixed carbon so that the reduction of metal oxide
Temperature reduction, rate of reduction is accelerated.Therefore, material 3 is not to be suitable for being heated using microwave under all temperature conditions.
Result illustrates full microwave mode when furnace temperature is relatively low, and efficiency is very low, and this will cause production cost uprises.
2）The rotary hearth furnace device of full microwave mode heat supply, its cost of investment is than conventional fuel combustion heat supply rotary hearth furnace device
Cost of investment will be higher by tens times of even hundred times, particularly in the feelings that current HIGH-POWERED MICROWAVES heater price is very expensive
Under condition, its investment cannot can bear for enterprise.And, the life-span of microwave device and maintenance cost are to production run and economy
Strong influence can be produced, is also that full ripple slightly is difficult to industrialized another reason.
3）Current full microwave mode is a blank, provide only a conception of species, does not there is matching, Neng Gougong
The complete design of industry, wherein the technology such as fume emission, controling of the pressure of the oven under many technical problems such as microwave reduction was not
There is any research.
The content of the invention
The technical problem to be solved in the present invention is that：For the technical problem that prior art is present, the present invention provides one
Kind of simple structure, investment and low production cost, degree of metalization be high, the microwave fuel combined heat formula coal of easy realization and popularization and application
Base directly reducing method and the rotary hearth furnace based on the method.
In order to solve the above technical problems, the present invention uses following technical scheme：
A kind of microwave fuel combined heat formula coal-based direct reduction method, material goes back original work by drying and preheating to enter
Industry；Material is reduced first with the mode of fuel combustion, material is carried out further by the way of microwave then
Reduction；Metal oxide be reduced to metal needed for the fixed carbon that comes from material of reducing agent.
As the further improvement of the inventive method：When being reduced using fuel combustion mode, using burner combustion
Fuel heat supply, the high-temperature flue gas of generation are heated and reduced to the material, and reduction temperature is 900~1250 DEG C；Using
When microwave mode is reduced, by microwave heat supply, the material is heated and reduction is catalyzed, reduction temperature is
950~1300 DEG C.
The present invention further provides a kind of microwave fuel combined heat formula coal-based direct reduction rotary hearth furnace, including the stove for rotating
Bed and bonnet, it is characterised in that sequentially form cloth section, drying and preheating section, fuel combustion along the rotation direction of the siege
Reduction section, microwave reduction section and discharge zone；Burner is provided with the fuel combustion reduction section, in microwave reduction
Section is provided with for producing microwave）Microwave component.
As the further improvement of apparatus of the present invention：Side near microwave reduction section in the discharge zone is provided with
Furnace pressure control device, the reducibility gas flow direction of the microwave reduction section is identical with the rotation direction of siege, described
The reducibility gas produced at microwave reduction section are discharged from furnace pressure control device.
As the further improvement of apparatus of the present invention：Chimney is provided near the side of cloth section in drying and preheating section, it is described
The flue gas of fuel combustion is discharged from chimney.
As the further improvement of apparatus of the present invention：Between fuel combustion reduction section and microwave reduction section, microwave
Envelope wall is equipped between radiation reduction section and discharge zone.
As the further improvement of apparatus of the present invention：Along the rotation direction of the siege, microwave reduction section with
Cooling section is set between discharge zone.
As the further improvement of apparatus of the present invention：Side near cooling section in the discharge zone is provided with controling of the pressure of the oven
Device, the reducibility gas flow direction for stating microwave reduction section is identical with the rotation direction of siege, the microwave spoke
The reducibility gas for penetrating reduction section generation are discharged from furnace pressure control device.
As the further improvement of apparatus of the present invention：Between the fuel combustion reduction section and microwave reduction section,
Envelope wall is equipped between microwave reduction section and cooling section.
As the further improvement of apparatus of the present invention：As the further improvement of apparatus of the present invention：In the drying and preheating
Section is provided with chimney near the side of cloth section, and the flue gas produced by fuel combustion is discharged from chimney.
As the further improvement of apparatus of the present invention：In drying and preheating section, material on siege by siege remaining temperature
600~900 DEG C are heated to the fume afterheat of fuel combustion；In the fuel combustion reduction section, by the burner combustion fuel
Heat supply, the high-temperature flue gas of generation are heated and reduced to material, and reduction temperature is 900~1250 DEG C；In the microwave
Reduction section, by microwave heat supply, is heated and is catalyzed reduction to the material, and heating process produces reducibility gas, also
Former temperature is 950~1300 DEG C；The flow of flue gas direction of the fuel combustion is opposite with the rotation direction of siege.
As the further improvement of apparatus of the present invention：The length of the microwave reduction section is that correspondence central angle is accounted for entirely
The 10/360~60/360 of rotary hearth furnace one week.
As the further improvement of apparatus of the present invention：The cloth section and discharge zone between, cloth section and drying and preheating
Between section, between discharge zone and microwave reduction section, envelope wall is respectively provided between discharge zone and cooling section.
Compared with prior art, the advantage of the invention is that：Microwave fuel combined heat formula coal base of the invention is directly gone back
Former rotary hearth furnace, simple structure, investment and low production cost, degree of metalization high, easy realization and popularization and application；Rotary hearth furnace of the invention
Material be in low-temperature condition when, heated and reduced using burner combustion fuel, so as to avoid occur microwave with
Coupling between low-temperature material is weaker, microwave is to the radiant heating speed relatively slow, thermal efficiency of metal oxide material
Very low problem.Meanwhile, after temperature of charge rises to be reached to a certain degree, then it is heated and is urged by microwave
Change reduction, this enhances the activity of metal oxide, accelerate the gasification reaction speed of fixed carbon, and cause metal oxide
Reduction temperature reduction, rate of reduction accelerate.It is final to improve and ensure that whole in all the period of time that material runs in rotary hearth furnace
Rotary hearth furnace equipment it is high-effect, reduce operating cost.From the point of view of another angle, due to using the side of local microwave
Formula, so being greatly reduced cost of investment, reduces the difficulty of rotary hearth furnace manufacture assembling, is advantageously implemented industrialization and market
Popularization and application.
Brief description of the drawings
Fig. 1 is the overlooking the structure diagram of the conventional rotary hearth furnace containing cooling section in the prior art.
Fig. 2 is the deployed configuration schematic diagram of the conventional rotary hearth furnace containing cooling section in the prior art.
Fig. 3 is the overlooking the structure diagram of the conventional rotary hearth furnace without cooling section in the prior art.
Fig. 4 is the deployed configuration schematic diagram of the conventional rotary hearth furnace without cooling section in the prior art.
Fig. 5 is the overlooking the structure diagram of full microwave mode rotary hearth furnace in the prior art.
Fig. 6 is the deployed configuration schematic diagram of full microwave mode rotary hearth furnace in the prior art.
Fig. 7 is the overlooking the structure diagram without cooling structure multistage heat-supply type rotary hearth furnace of the invention.
Fig. 8 is the deployed configuration schematic diagram without cooling structure multistage heat-supply type rotary hearth furnace of the invention.
Fig. 9 is the overlooking the structure diagram of the heat-supply type rotary hearth furnace of multistage containing cooling structure of the invention.
Figure 10 is the deployed configuration schematic diagram of the heat-supply type rotary hearth furnace of multistage containing cooling structure of the invention.
Figure 11 is with the elevated iron ore concentrate change in dielectric constant trend schematic diagram of temperature.
Figure 12 is with the elevated iron ore concentrate magnetic conductivity variation tendency schematic diagram of temperature.
Marginal data：
1st, burner；2nd, siege；3rd, material；4th, bonnet；5th, wheel；6th, chimney；7th, envelope wall；8th, material distributing machine；9th, cooling water
Pipe；10th, unloader；11st, cooler；12nd, microwave；13rd, furnace pressure control device；101st, cloth section；102nd, drying and preheating section；
103rd, fuel combustion reduction section；104th, microwave reduction section；105th, cooling section；106th, discharge zone.
Specific embodiment
Below with reference to Figure of description and specific embodiment, the present invention is described in further detail.
Electromagnetic performance is the internal cause for embodying material and microwave coupling ability to function, and the electromagnetic performance of material determines material
Micro-wave heating characteristic, is that can material by the basic of heating using microwave.From material electromagnetic performance in itself, research influence material is removed
Material absorbs the ability of microwave, and the factor of main examination has the complex dielectric permittivity of material（Real part of permittivity ε 'rWith imaginary part ε "r）, because
It is the mainly dielectric loss of influence material warms in microwave electromagnetic field.But the electromagnetic performance of material also can be with temperature
The change of factor such as change, thing phase and structure and there is very big variation.The result that studies for a long period of time shows（As shown in figure 11）, when
Magnetite concentrate is put into microwave field when heating, below 400 DEG C, the real part of permittivity ε ' of magnetite concentraterWith imaginary part ε "rChange
Less, after exceeding this temperature, ε 'rWith ε "rRapid increase.According to formula（1）Understand, as temperature is raised, the liter of material
Warm speed is accelerated, and the functioning efficiency of microwave is improved.
ε=ε0·ε″eff=ε0(ε′-jε″) （2）
μ=μ0·μ″eff=μ0(μ′-jμ″) （3）
In formula, f represents frequency (Hz), and ε ' represents real part of permittivity, ε " represents imaginary part of dielectric constant, E represents electric-field strength
Degree size, H represents magnitude of field intensity, ε0It is permittivity of vacuum, ε "effIt is effective relative dielectric loss factor, μ "effIt is
Effective relative magnetic loss factor, ρ is density of material, and C is sample specific heat capacity, qDamageIt is to be caused due to radiation, convection current and conduction
Heat loss.
As shown in figure 12, when magnetite concentrate is put into be heated in microwave field, before 550~600 DEG C, magnetic conductivity（Magnetic conductance
The real part μ ' of raterWith imaginary part μ "r）Change is little, and after 600 DEG C, magnetic conductivity disappears close to null value, the magnetic of material.For
Magnetite concentrate material, after temperature is more than 600 DEG C, dielectric loss turns into the major way that heating using microwave heats up.
Based on a kind of theoretical above, microwave fuel combined heat formula coal-based direct reduction method of the invention, step is：Thing
Material enters reduction operation by drying and preheating, and material is reduced first with the mode of fuel combustion, then using microwave
The mode of radiation carries out the reduction of a step to material, and metal oxide is reduced into metal by the final fixed carbon using in material.
In concrete application example, when being reduced using fuel combustion mode, using burner combustion fuel heat supply, produce
High-temperature flue gas material is heated and reduced, reduction temperature be 900~1250 DEG C；Gone back using microwave mode
When former, by microwave heat supply, reduction is heated and is catalyzed to the material, reduction temperature is 950~1300 DEG C.
Further, as shown in Figure 7 and Figure 8, the present invention proposes a kind of microwave fuel combined heat formula coal-based direct reduction
Rotary hearth furnace, siege 2 in Fig. 7 along rotating clockwise direction（Solid arrow direction in Fig. 7）Or along being rotated from left to right in Fig. 8
Direction（Solid arrow direction in Fig. 8）, successively by cloth section 101, drying and preheating section 102, fuel combustion reduction section 103, microwave
Radiation reduction section 104, discharge zone 106 is constituted, and burner 1 is provided with fuel combustion reduction section 103, and burner 1 is installed on corresponding area
On the medial and lateral wall of bonnet 4 in domain, the microwave group for producing microwave 12 is provided with microwave reduction section 104
Part；In other words, the whole reduction section of rotary hearth furnace is constituted by two sections, and every section of heat-supplying mode is different, near drying and preheating section 102
Side by the burning fuel heat supply of burner 1, in the microwave 12 produced by microwave component near the side of discharge zone 106
Heat supply, microwave 12 also has the effect of catalysis reduction simultaneously.
In the present embodiment, 101 material distributing machine 8 is provided with cloth section, after blended pelletizing containing fixed carbon（Contain the particle of charcoal
Thing）And metal oxide（That is the particulate matter of containing metal oxide）Material 3（It is commonly called as green-ball）Uniformly it is laid in by material distributing machine 8 and is turned
On the siege 2 of bottom stove, rotated clockwise with the siege 2 driven by wheel 5（Such as Fig. 7 solid arrows direction）Or from left to right
Rotate（Such as Fig. 8 solid arrows direction）.Material 3 enters drying and preheating section 102, by the flue gas of the gentle fuel combustion of siege more than 2
To 600~900 DEG C, moisture, volatile part are progressively removed waste-heat.Incoming fuel burning reduction section 103, is adopted by burner 1
With traditional burning fuel mode heat supply, material 3 is heated and reduced, in about 900~1250 DEG C of reduction temperature condition
Under, the fixed carbon in material 3 starts to gasify and metal oxide is reduced into metal.Into microwave reduction section 104, by micro-
The heat supply of microwave 12 that wave radiation component is produced, the metal oxide in material 3 is completely reduced, and reduction temperature is 950~
1300℃.Under the conditions of the reduction temperature, the not only radiant heating ability enhancing of microwave itself, and microwave 12 can be strengthened
In the range of in material 3 metal oxide activity, accelerate the gasification reaction speed of fixed carbon in material 3, and make metal oxide
Reduction temperature reduction, rate of reduction accelerate, make microwave 12 have catalysis reduction effect.Material 3 is after fuel combustion
After reduction section 103 and microwave reduction section 104, degree of metalization is up to more than 92%.Material 3 after reduction is final by discharge zone
The discharge rotary hearth furnace of unloader 10 at 106, molten point of heating is carried out into cooler 11 or into mineral hot furnace.
By using said structure of the invention, when material 3 is in low-temperature condition, using the confession of the burning fuel of burner 1
Hot mode is heated and reduced, so as to avoid coupling under cryogenic between microwave 12 and material 3 compared with
Weak, microwave 12 is to asking that the radiant heating speed very low phenomenon of the relatively slow, thermal efficiency of metal oxide material 3 is produced
Topic.The incoming fuel of material 3 burning reduction section 103, temperature is further raised, the fixed carbon gasification in part, produces reduction reaction, then
Into microwave reduction section 104, then it is continued by microwave 12 heat and be catalyzed reduction.This not only increases metal
The activity of oxide, accelerates the gasification reaction speed of fixed carbon, and causes that the reduction temperature of metal oxide is reduced, reduction
Speed is accelerated.It is final to ensure that the high-effect of whole rotary hearth furnace equipment in all the period of time that material 3 runs in rotary hearth furnace, reduce
The operating cost of rotary hearth furnace.From the point of view of another angle, due to using the mode of local microwave, so being greatly reduced
Cost of investment, reduces the difficulty of manufacture assembling, the need for can meeting marketing.
It is generally right depending on the length of microwave reduction section 104 need to be according to the different qualities of material 3 in the present embodiment
Central angle is answered to account for the 10/360~60/360 of whole rotary hearth furnace one week, this is the prioritization scheme obtained by experiment.
In another embodiment, as shown in Figure 9 and Figure 10, can also be further along the rotation direction of siege 2, micro-
Cooling section 105 is set between wave radiation reduction section 104 and discharge zone 106, the material 3 after microwave reduction is completed through being equipped with
After the cooling section 105 of cooling water pipe 9 is cooled down, rotary hearth furnace is finally discharged by unloader 10, into cooler 11 or enter mineral hot furnace
Carry out molten point of heating.Cooling water pipe 9 is laid in the bonnet 4 corresponding to cooling section 105.
In the present embodiment, further except being provided with envelope wall 7 in cloth 101 rear ends of section and the front end of discharge zone 106, herein
The effect of envelope wall 7 is to prevent the flue gas at cloth section 101 from running helter-skelter to discharge zone 106, allows cloth section 101 and discharge zone as far as possible
106 atmosphere and temperature do not interfere with each other.Outside, and also in the front and back end of microwave reduction section 104, i.e. fuel combustion reduction section
Between 103 and microwave reduction section 104, between microwave reduction section 104 and cooling section 105（During without cooling section 105, it is
Between microwave reduction section 104 and discharge zone 106）Envelope wall 7 is equipped with, to prevent air or oxidizing gas from entering microwave spoke
Penetrate reduction section 104, it is to avoid reoxidizing for reducing metal is leaked with microwave.The purpose for preventing microwave from leaking has two：First is
Allow microwave action in microwave reduction section 104 as far as possible, improve microwave energy utilization ratio；Second is to prevent microwave leakage to combustion
After material burning zone, continue to be leaked into outside stove from chimney 6 and cloth section 101（Because, fuel combustion reduction section 103 and chimney 6 and cloth
Material section 101 is connection）, cause safety problem.
In the present embodiment, chimney 6, the high temperature that fuel combustion reduction section 103 is produced are provided with the front end of drying and preheating section 102
Flue gas flow direction is in opposite direction with what siege 2 was rotated, the void as corresponding to fuel combustion reduction section 103 in Fig. 7, Fig. 8, Fig. 9, Figure 10
The line direction of arrow, through drying and preheating section 102 after, discharged from chimney 6.Fuel combustion reduction section 103 produce high-temperature flue gas with
The counter current contacting of material 3 that siege 2 is rotated, heated material 3 makes its top layer fix carbon gasification and reduces metal oxide, then
Continue the counter current contacting of material 3 with drying and preheating section 102, moisture, volatile part are progressively removed.
In the present embodiment, further between the rear end of cooling section 105 and unloader 10（It is microwave when without cooling section 105
Between radiation reduction 104 rear ends of section and unloader 10）Furnace pressure control device 13 is provided with, what microwave reduction section 104 was produced goes back
The direction that originality high-temperature gas is flowed to siege 2 is rotated is identical, such as the institute of fuel combustion reduction section 103 in Fig. 7, Fig. 8, Fig. 9, Figure 10
Corresponding dotted arrow direction, through cooling section 105（（When there is cooling section 105）, after discharge zone 106, from furnace pressure control device 13
Top discharge.The Main Function of furnace pressure control device 13 is to ensure that in microwave reduction section 104 reproducibility of atmosphere and also
Former reaction speed.
Micro-vacuum state is remained in rotary hearth furnace, after preventing from being revealed because of sealing problem, causes the reproducibility in stove
Gas（Belong to imflammable gas）Leak, produce inflammable and explosive safety issue.
One of effect of microwave reduction section 104 is the oxidizing atmosphere for avoiding burning fuel from producing to reducing metal
Reoxidize.During rotary hearth furnace normal work, the gas pressure in bonnet 4 is in micro-vacuum state.The furnace pressure provided by the present invention
Control device 13 so that the gas pressure absolute value of rotary hearth furnace microwave reduction section 104 is slightly above fuel combustion adjacent thereto
The gas pressure of reduction section 103, discharge zone 106 or cooling section 105 is burnt, the flue gas and discharge of fuel combustion reduction section 103 is prevented
The gas of section 106 or cooling section 105 enters, it is ensured that the reproducibility of atmosphere in microwave reduction section 104.Additionally, material 3 is turning
Direct Reduction in the stove of bottom is reacted by indirect reduction（1）And gasification reaction（2）Collectively constitute, reducing agent is derived from
Fixed carbon.The speed of Direct Reduction receives gasification reaction（2）Control, gasification reaction（2）It is an increase-volume reaction, if stove
Pressure is raised, then reaction equation（2）The speed for carrying out to the right declines so that CO partial pressures reduction in balance gas phase, and then causes reaction equation
（1）The speed for carrying out to the right declines.Therefore, the gas of rotary hearth furnace microwave reduction section 104 is caused by furnace pressure control device 13
Body pressure absolute value is slightly above the gas pressure of fuel combustion reduction section 103, discharge zone 106 or cooling section 105 adjacent thereto,
Both can ensure that the gas that reaction is produced smoothly flows to outer row after furnace pressure control device 13, ensure that the reduction of atmosphere in rotary hearth furnace
Gesture, it is also ensured that the speed of whole reduction reaction.
MexOy+yCO=xMe+yCO2（1）
xC+xCO2=2xCO （2）
In whole rotary hearth furnace device operation process, flow of flue gas direction and material 3 that fuel combustion reduction section 103 is produced
Rotation direction is reverse（The direction of the place respective dashed of fuel combustion reduction section 103 in Fig. 7, Fig. 9）, it is pre- through drying and preheating section 102
After thermal material 3, discharged from chimney 6.In the presence of furnace pressure control device 13, the gas pressure of microwave reduction section 104 is exhausted
Slightly above adjacent fuel combustion reduction section 103, discharge zone 106 are in value（During without cooling section 105）Or the pressure of cooling section 105
Power state, microwave reduction section 104 produce gas in the presence of furnace pressure control device 13, most of gas flow direction
It is in the same direction with the rotation direction of material 3（Direction in Fig. 7, Fig. 9 at microwave reduction section 104 shown in dotted line）, from controling of the pressure of the oven dress
13 top discharge is put, a small amount of gas meeting incoming fuel burning reduction section 103 is discharged by chimney 6 in the lump.
The above is only the preferred embodiment of the present invention, protection scope of the present invention is not limited merely to above-described embodiment,
All technical schemes belonged under thinking of the present invention belong to protection scope of the present invention.It should be pointed out that for the art
For those of ordinary skill, some improvements and modifications without departing from the principles of the present invention should be regarded as protection of the invention
Scope.
Claims (12)
1. a kind of microwave fuel combined heat formula coal-based direct reduction method, it is characterised in that material（3）By drying and preheating
Into reduction operation；First with the mode of fuel combustion to material（3）Reduced, then to thing by the way of microwave
Material（3）Further reduced；Reducing agent needed for metal oxide is reduced to metal comes from material（3）In fixed carbon；
When being reduced using fuel combustion mode, using burner（1）Burning fuel heat supply, the high-temperature flue gas of generation are to the material
（3）Heated and reduced, reduction temperature is 900~1250 DEG C；When being reduced using microwave mode, by microwave spoke
Heat supply is penetrated, to the material（3）Reduction is heated and is catalyzed, reduction temperature is 950~1300 DEG C.
2. a kind of microwave fuel combined heat formula coal-based direct reduction rotary hearth furnace, including the siege for rotating（2）And bonnet（4）, its
It is characterised by, along the siege（2）Rotation direction sequentially form cloth section（101）, drying and preheating section（102）, fuel combustion
Burn reduction section（103）, microwave reduction section（104）And discharge zone（106）；In the fuel combustion reduction section（103）It is provided with
Burner（1）, in the microwave reduction section（104）It is provided with for producing microwave（12）Microwave component.
3. microwave fuel combined heat formula coal-based direct reduction rotary hearth furnace according to claim 2, it is characterised in that in institute
State discharge zone（106）In near microwave reduction section（104）Side be provided with furnace pressure control device（13）, the microwave
Reduction section（104）Reducibility gas flow direction and siege（2）Rotation direction it is identical, the microwave reduction section
（104）Locate the reducibility gas for producing from furnace pressure control device（13）Discharge.
4. microwave fuel combined heat formula coal-based direct reduction rotary hearth furnace according to claim 3, it is characterised in that dry
Dry preheating section（102）Near cloth section（101）Side be provided with chimney（6）, the flue gas of the fuel combustion is from chimney（6）Row
Go out.
5. microwave fuel combined heat formula coal-based direct reduction rotary hearth furnace according to claim 2, it is characterised in that in combustion
Material burning reduction section（103）With microwave reduction section（104）Between, microwave reduction section（104）With discharge zone（106）It
Between be equipped with envelope wall（7）.
6. microwave fuel combined heat formula coal-based direct reduction rotary hearth furnace according to claim 2, it is characterised in that along
The siege（2）Rotation direction, in microwave reduction section（104）With discharge zone（106）Between cooling section is set（105）.
7. microwave fuel combined heat formula coal-based direct reduction rotary hearth furnace according to claim 6, it is characterised in that in institute
State discharge zone（106）In near cooling section（105）Side be provided with furnace pressure control device（13）, it is described to state microwave reduction section
（104）Reducibility gas flow direction and siege（2）Rotation direction it is identical, the microwave reduction section（104）Produce
Reducibility gas from furnace pressure control device（13）Discharge.
8. microwave fuel combined heat formula coal-based direct reduction rotary hearth furnace according to claim 6, it is characterised in that in institute
State fuel combustion reduction section（103）With microwave reduction section（104）Between, microwave reduction section（104）And cooling section
（105）Between be equipped with envelope wall（7）.
9. microwave fuel combined heat formula coal-based direct reduction rotary hearth furnace according to claim 6, it is characterised in that in institute
State drying and preheating section（102）Near cloth section（101）Side be provided with chimney（6）, flue gas produced by fuel combustion is from chimney
（6）Discharge.
10. the microwave fuel combined heat formula coal-based direct reduction rotary hearth furnace according to any one in claim 2~9,
Characterized in that, in drying and preheating section（102）, siege（2）On material（3）By siege（2）Remaining gentle fuel combustion
Fume afterheat be heated to 600~900 DEG C；In the fuel combustion reduction section（103）, by the burner（1）Burning fuel is supplied
Heat, the high-temperature flue gas of generation are to material（3）Heated and reduced, reduction temperature is 900~1250 DEG C；In the microwave
Reduction section（104）, by microwave（12）Heat supply, to the material（3）Reduction is heated and is catalyzed, heating process is produced also
Originality gas, reduction temperature is 950~1300 DEG C；The flow of flue gas direction of the fuel combustion and siege（2）Rotation direction
Conversely.
The 11. microwave fuel combined heat formula coal-based direct reduction rotary hearth furnace according to any one in claim 2~9,
Characterized in that, the microwave reduction section（104）Length be that correspondence central angle accounts for the 10/360 of whole rotary hearth furnace one week
~60/360.
The 12. microwave fuel combined heat formula coal-based direct reduction rotary hearth furnace according to any one in claim 2~9,
Characterized in that, in cloth section（101）And discharge zone（106）Between, cloth section（101）With drying and preheating section（102）It
Between, discharge zone（106）With microwave reduction section（104）Between, discharge zone（106）And cooling section（105）Between be respectively provided with it is close
Envelope wall（7）.
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| CN107151722B (en) * | 2016-03-02 | 2023-03-10 | 中冶长天国际工程有限责任公司 | Microwave fuel combined heating coal-based direct reduction test device and method |
| CN105907405A (en) * | 2016-06-15 | 2016-08-31 | 江苏省冶金设计院有限公司 | Rotary hearth furnace and method for treating low-rank coal and iron-containing materials |
| CN106011458B (en) * | 2016-06-24 | 2017-11-17 | 长沙有色冶金设计研究院有限公司 | The method and its equipment of high arsenic multi-metal complex material dearsenification |
| CN108913897A (en) * | 2018-08-06 | 2018-11-30 | 王德清 | A kind of energy conservation ferrochrome production method |
| CN111172405A (en) * | 2020-02-27 | 2020-05-19 | 北京矿冶科技集团有限公司 | Microwave rotary hearth furnace chlorination gold extraction device and method |
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