CN1789437A - Slit type ladle bottom blowing powder injection process and apparatus - Google Patents

Abstract

The invention relates narrow slit type ladle bottom-blown dusting technology, comprising the following steps: conveying fluidized dust to narrow slit type air brick by dusting pot system, then spraying the dust into molten steel with narrow slit type air brick. The narrow slit type ladle bottom-blown dusting device comprises pipe line, dusting pot system, narrow slit type air brick which is set in the bottom of ladle and connected with dusting pot system. The invention comprises the following steps: easy to realize; safety and high reliability, avoiding the stoppage, meeting all requirements of gas content in many conditions; immediately removing the desulfurization product to clean the molten steel; good stirring effect; saving the up-down device and low cost of technical innovation.

Description

Slit type ladle bottom blowing powder injection process and device

Technical field

The invention belongs to iron and steel refining techniques field, be specifically related to slit type ladle bottom blowing powder injection process and device.

Background technology

The purity that improves steel can improve the mechanical property of steel significantly.The development of high Clean Steel production technique and equipment is one of emphasis of Iron and Steel Enterprises in China composition optimizes.Along with the development of society is more and more higher to the requirement of steel, even mass-produced staple is also answered the deterioration of working conditions and had higher requirement.Table 1 is the trend of impurity element monomer controlled levels development in the steel.

Impurity element monomer controlled levels development trend (* 10 in table 1 steel ^-6)

As can be seen from Table 1, the user is more and more harsher to the requirement of sulphur in the steel.Sulphur in the steel can cause hot-short, and the long strip shape in the steel (especially distributing along crystal boundary) sulfide is the necessary condition that produces hydrogen induced cracking, so sulphur is harmful element (easily except the smear metal steel) in most of steel, wishes to control low more well more.

The thermodynamic condition of desulfurization is high temperature, high basicity, low oxidisability.The characteristics of converter steelmaking process itself have determined that the ideal desulfurization process is at hot metal pretreatment and secondary refining, and secondary refining be control steel in the sulphur composition last the ring operation, its final decision in the steel constituent content whether meet customer requirements.Although there are production practice both domestic and external to show, hot metal pretreatment is to smelt more effective, the economic technical guarantee of Clean Steel, the prerequisite that also is absolutely necessary operation, but because oxidizing atmosphere that converter smelting has is unfavorable for desulfurization (even might increase sulphur) very much, so depending merely on hot metal pretreatment, to come sulphur removal to make it to reach the finished product requirement be unpractical.The secondary refining process of various desulfurization has appearred for this reason, and as shown in table 2.

Table 2 secondary refining process and sweetening effectiveness thereof

Technology	Method of refining	Refining effect/10 -6
			TN、KIP	Winding-up CaO-CaF 2-Al 2O 3Or Ca-Si	[S]＜10
LF	The reductibility slag is made in heating	[S]＜10
			V-KIP	Vacuum is dusted	[S]＜10
VD	The vacuum slag making	[S]＜10
			VOD-PB、RH-PB	Vacuum spray CaO-CaF 2Powder	[S]＜2

Wherein, dust because of using fine powder, greatly increased specific surface area and brought up good dynamic conditions, and generally used, the vector gas of pulvis can stir molten steel again, has accelerated mass transfer.

At present, the dusting device of secondary refining can simply be divided into two kinds by the mode of spraying in ladle: a kind of is directly to spray in ladle, and another kind is indirect spray.Preceding a kind of as TN, KIP, V-KIP, VOD-PB, RH-PB etc., and RH-PTB etc. belong to the latter.The method commonly used of directly dusting in the ladle is to spray into by spray gun.

Spray gun can be divided into consumable formula spray gun and non-consumable formula spray gun again, and the advantage of consumable formula spray gun is to make simply, and is cheap, but shortcoming is:

1. work under bad environment;

2. increased labor intensity of operating personnel;

3. Cao Zuo poor stability.

Non-consumable formula spray gun has overcome the shortcoming of consumable formula spray gun, use at present wider, but present stage himself shortcoming also very obvious, specific as follows:

1. spray gun is to consume spare unit, and price is higher, and its life-span is directly connected to the cost of refining treatment technology.Therefore making great efforts to prolong service life of lance is one of important measures that reduce desulphurization cost.As long as spray gun inserts ladle, just unavoidably to contact with slag, slag takes place invade, scouring is one of key factor that shortens spray gun work-ing life.

2. spray gun also can enterprise's self manufacture.Self manufacture needs vibration type system gunlock, and make in the refractory materials and be mixed with steel fiber, and the spray gun roaster.Spray gun making and baking there are strict requirement, just can obtain qualified spray gun.Stove is fuel used according to the enterprise condition decision, designs roaster by fuel.

Might touch convex closure when 3. spray gun descends, cause huge vibrations, can only mention spray gun this moment, and ladle hangs away, has a strong impact on molten steel processing plan and production scheduling.

4. the spray gun stroke is certain, and the liquid steel level height but might change, and changes greatlyyer sometimes, is not to enter too deeply when making rifle work, enters too shallowly exactly, and influence is operated stablely, is unfavorable for the production direct motion.And the stroke of rifle can not all be transferred at every turn, even transfer, also do not have the data of liquid steel level height, so this has become long-standing problem.

When accidents such as contingency generation power failure, present spray gun both domestic and external all is stymied by, and has not only damaged rifle when 5. jetting, and Baogang's water all might be scrapped.

6. the work-ing life of spray gun is not long at present, and the baking of dress rifle is time-consuming, if the danger of influential steel quality is fallen in the molten steel in the spray gun fracture.

RH-PTB (Ruhrsstahl Heraeus---Powder Top Blowing) is that RH top powder injection process is to be equipped with powder spraying system on RH-KTB method (Ruhrsstahl Heraeus-Kawatetsn top Blowing) is the basis of top blowing oxygen recirculation degassing, by top rifle blowing desulfurization pulvis in the vacuum chamber molten steel, constitute RH-PTB (or RH-KTB/PB) technology, can realize the vacuum powder injection desulphurization.Pulvis is sprayed into by water-cooled top rifle, as shown in Figure 1.This method advantage is:

1. there is not the spray gun blockage problem;

2. there is not refractory consumption rate;

3. load volume is little, because of no molten steel resistance.

Shortcoming is:

1. if the rifle position in the RH is too high, influence sweetening effectiveness; Also can cause powder gas shock RH inwall, shorten the work-ing life of inwall refractory materials.

2. if the position of lances in the RH is low excessively, shower nozzle is easily tied cold steel; And easily burnt out by molten steel.

3. water cooled lance is to be made by the multilayer weldless steel tube, costs an arm and a leg.

4. very easily cause Serious Accident as if cut off the water suddenly or power failure etc.

Also all there is potential safety hazard in above-mentioned various method of refining except that many self shortcomings are arranged, therefore be necessary to develop a kind of not only safety but also inexpensive, possesses the refinery practice of preferable sweetening effectiveness simultaneously again.

Summary of the invention

Weak point at existing iron and steel refinery practice and device the invention provides a kind of slit type ladle bottom blowing powder injection process and device.

Slit type ladle bottom blowing powder injection device of the present invention mainly is made up of powder spraying pot system and slot-type ventilating brick, as shown in Figure 2.

The powder spraying pot system is made up of weighing device and control device, and wherein weighing device dynamically shows pulvis weight by load sensor, and signal is passed to Controlling System, and then decision winding-up amount and time.The powder spraying pot system divides manually control and control automatically.Manually control is mainly used in debugging at ordinary times, and interlock is in closing condition, and control is by the omnidistance program control and computer operation of PLC automatically, and interlock is in opened condition.One storage bunker 8 is arranged at powder spraying pot 12 tops, and the blanking amount is controlled by the feed valve between the two 10.After treating that a jar internal pressure reaches certain value, delivering gas begins to supply gas, and blanking ball valve 15 is opened, and powder spraying pot begins powder down, and material constantly is brought into pipe-line transportation to gas permeable brick.

Have the slit that an arrowhead distributes axisymmetricly in the middle of the slot-type ventilating brick, the length in slit changes wavelength width of a slit by the exit diameter decision of gas permeable brick on the basis of gas permeable brick commonly used, enables the pulvis winding-up effect that reaches best.The height of gas permeable brick is determined by ladle bottom thickness.Structure as shown in Figure 3, Figure 4.The width of slit in theory can be definite by following formula,

r＝-2σcosθ/ρgh (1)

R-slit width in the formula

σ-molten steel surface tension

ρ-molten steel proportion

G-universal gravity constant

The h-melt pool height

The contact angle of θ-molten steel and anti-material.

As can be seen from the above equation, can molten steel infiltrate the gas supply element pore and depend primarily on contact angle and gas supply element pore radius between melt pool height, molten steel surface tension, molten steel and the refractory materials.As calculated, the molten steel height is greater than the ladle of 2m, and its air supply brick pore radius must be less than 15 μ m in theory, and molten steel just can not infiltrate.Also can not ooze steel when in fact the hole diameter of air supply brick is the hundreds of micron, this is to stop molten steel to infiltrate pore because refractory materials produces a kind of gluey liquid film under the effect of high-temperature molten steel.In order to reach best pulvis winding-up effect, slit width should be limited in 0.1mm～0.3mm, when the molten steel height is higher, suitably reduces slit width.

Be connected by pipeline between powder spraying pot system and the slot-type ventilating brick.

The technology that the employing said apparatus carries out bottom blowing powder injection is as follows:

Carry qualified fluidised pulvis by the powder spraying pot system to slot-type ventilating brick, by slot-type ventilating brick pulvis is sprayed into the molten steel from ladle bottom again.Various injection parameters can be regulated arbitrarily immediately during manual operation.If during by microcomputer control, whole winding-up action is carried out automatically by preset program.Concrete winding-up process is as follows: powder is delivered into powder spraying pot 12 from storage bunker 8, add powder after, the beginning pressurization of supplying gas in the powder spraying pot 12.(the powder spraying pot pressure parameter needs according to the concrete working conditions in scene when pressure reaches certain value, the debugging back is determined), the gas control shutoff valve 23 of control drainage gas is opened, drainage gas is started working, open the fluidizing agent in the vaporizer 14 then, open the blanking ball valve 15 of powder spraying pot lower part outlet at last, the action beginning of dusting, powder begins to be transported to gas permeable brick.Powder enters the air chamber of gas permeable brick, and slit is given in reallocation, arrives in the molten steel by slit.

After carrying beginning, the material in the powder spraying pot is constantly brought into pipeline by air-flow, and along with the material in the pipeline is on the increase, the operating pressure of powder spraying pot also constantly increases, and this process is for carrying initial period.When pressure reached certain value, the operating pressure of powder spraying pot did not again raise, and kept constant, and promptly enter delivery phase this moment, and in this stage, the powder spraying pot transportation concentration is also higher, so efficient is also higher.Along with material in the jar constantly reduces, the operating pressure of powder spraying pot also constantly reduces, and promptly enter purge stages this moment, promptly carries ending phase.When powder spraying pot pressure is reduced to certain value (keep constant or the speed that reduces very slow), i.e. expression is carried and is finished.Intake valve cuts out then, thereby enters next working cycle.

For guaranteeing the slot-type ventilating brick works better, powder delivery is smooth, this process using dilute phase intermittent delivery mode of operation, and one jar of material of every conveying is a working cycle.

Injection parameters is as follows:

(1) parameter request of pulvis:

1. particle diameter d _p≤ 0.2r (2)

D in the formula _p-pulvis diameter r-slit width

2. must be solid particulate

Pulvis is selected carbon dust, passive lime, Na for use ₂CO ₃Pulvis or CaSi alloy powder etc.

The powder to air ratio parameter request:

For preventing that gas permeable brick from stopping up, and requires the powder fraction by volume $\mathrm{\φ}=\frac{V_p}{V_{\mathrm{mix}}}\≤0.6---\left(3\right)$

φ in the formula-fraction by volume V _pThe volume V of-powder _MixThe cumulative volume of-powder and gas

(2) carrier gas requires:

1. the speed V of gas must be greater than the critical fluidization velocity V of powder in the pipeline _Mf, promptly

$V{>V}_{\mathrm{mf}}=\frac{(1-{\mathrm{\ϵ}}_{\mathrm{mf}})({\mathrm{\ρ}}_p-{\mathrm{\ρ}}_g)}{150\frac{{(1-{\mathrm{\ϵ}}_{\mathrm{mf}})}^2}{{{\mathrm{\ϵ}}_{\mathrm{mf}}}^2{\left({\mathrm{\φ}}_s\stackrel{\‾}{d_p}\right)}^2}+1.75\·\frac{1-{\mathrm{\ϵ}}_{\mathrm{mf}}}{{{\mathrm{\ϵ}}_{\mathrm{mf}}}^2}\frac{{\mathrm{\ρ}}_g}{{\mathrm{\φ}}_s\stackrel{\‾}{d_p}}}---\left(4\right)$

Gas velocity V in the V-transfer lime in the formula _Mf-critical fluidization velocity ε _Mf-critical voidage

ρ _p-pellet density ρ _g-gas density μ-gas viscosity

φ _s-sphericity

The mean diameter of-pulvis

2. in order to prolong gas permeable brick work-ing life, gas flow should satisfy following formula:

$Q>\frac{2100{\mathrm{\πd}}_0{\mathrm{\μ}}_l}{4{\mathrm{\ρ}}_g}---\left(5\right)$

Q-gas flow d in the formula ₀-nozzle inside diameter

ρ _gThe density μ of-gas _LThe viscosity of-liquid

The present invention has the following advantages:

1, relative various supporting technology comparative maturity is easy to realize.

Various supporting technologies mainly are the making and the hot swap technology of gas permeable brick, and the existing ability of present domestic most of refractory materials producer is produced the gas permeable brick of corresponding specification according to different technical requirementss.As for the hot swap technology of bottom-blown air brick, also comparative maturity at present, the popular way is to adopt to divide a body structure, promptly ventilative core brick+cover brick form.

2, the complete and reliability in Rong'an is an one.

Because refractory materials---the effect of molten steel interfacial tension, molten steel are difficult to soak into tiny slit, thereby have avoided latch up phenomenon.Bottom-blown air brick commonly used has 3 kinds of forms: diffuse type gas permeable brick, straight-through pass gas permeable brick and slot-type ventilating brick.Obviously, the diffuse type gas permeable brick is not suitable for being applied to dust.The two all possesses the primary condition of dusting straight-through hole shape and slit, and wherein straight-through pass bottom-blown air brick mainly contains two kinds of structure formations, and a kind of is the nozzle type gas permeable brick, and another kind is an orienting stephanoporate type gas permeable brick (MHP).The nozzle type gas permeable brick is relatively poor on safety, molten steel takes place easily ooze.Orienting stephanoporate type gas permeable brick (MHP) is a kind of more advanced technology.

The advantage of MHP brick is adjustable large-minded, and security is good, even under the extreme condition of dying, molten steel can be always not on earth yet, and solidify on air chamber top.As seen MHP mainly is suitable for converter, and converter can omnidistance oxygen blast, and ladle oxygen blast in the handling process will bring inconvenience to production, otherwise can cause molten steel to solidify on air chamber top, stops up gas permeable brick so that can't dust.So dust in ladle, slot-type ventilating brick is more excellent.

3, the adjustable scope of tolerance is big.

Slit has improved the dynamic conditions of gas greatly, and the tolerance regulation range reaches as high as more than 10 times.Can satisfy the ladle bottom blowing tolerance requirement under the various conditions.

4, investment for trnasforming urban land is low, does not change original technology.

In metallurgical process, in order to remove gas and the impurity in the molten steel, reach the purpose of even molten steel composition and temperature, domestic most of ladle all adopts blowing argon gas to smelt.A large amount of practice and theories prove that all this is the not only effective but also inexpensive technology of a cover.The dividing potential drop of obnoxious flavour in Argon Bubble is lower, thus one by one little Argon Bubble just just as one by one little vacuum chamber, and the Argon Bubble of come-up can drive and is mingled with come-up in the molten steel, and then is caught by slag.Ladle argon-blown can be divided into two kinds of top blast and bottom blowings, wherein steel ladle bottom argon blowing is because of being better than the top blast argon at aspects such as removing steel inclusion and obnoxious flavour, and occupied ground does not need the lifting hoisting equipment, and can reduce working strength of workers, extensively adopted by metallurgy industry.

For original steel ladle bottom argon blowing technology, only need gas permeable brick is replaced with slot-type ventilating brick, add a cover and supply the powder spraying pot system of powder to get final product.Saved the essential jacking equipment of top-blown powder institute, so the technological transformation cost is low.

5, the gas permeable brick melting loss is few.

About ladle bottom blowing gas supply element melting loss mechanism, what Chinese scholars was relatively admitted at present is following three aspects:

The bubble counterattack: the air-flow that is blown into the molten bath enters the molten bath in the bubble mode.Bubble disengagement gas supply element moment air-flow carries out ballistic phenomenon to refractory materials around the gas supply element and is called " bubble counterattack ".

Water hammer washes away: MOLTEN STEEL FLOW around causing when being the bubble disengagement gas supply element, wash away the gas supply element phenomenon of anti-material on every side.Airshed is big more, and the molten steel scouring that water hammer causes corrodes serious more.

Pit corrode: because washing away of gas and molten steel forms pit around gas supply element.Pit is dark more, and transmission of heat by convection is poor more, the aggravation erosion action.

In order to alleviate the bubble counterforce, require to strengthen the velocity of discharge that air-blowing quantity improves gas, when gas velocity during greater than critical velocity, the bubble counterforce disappears, but after the tolerance increasing, water hammer washes away aggravation.When gas was the dispersive bubble in the gas permeable brick outlet, the influence of bubble counterforce be can not ignore; When gas was jet in the gas permeable brick outlet, the bubble counterforce can be ignored.

David Laibsons etc. are according to the experimental result of air one aqueous systems, and the nozzle Reynolds number condition that proposes formation dispersive bubble is:

Re ₀＝Ud ₀ρ _g/μ _L＜2100 (6)

The gas flow rate d of U-nozzle place in the formula ₀-nozzle inside diameter ρ _gThe density of-gas

μ _LThe viscosity of-liquid

When gas flow increases to Re ₀＞2100, in the time of may entering the fluerics, the gas that sprays into is split into many small bubbles very soon, and Re ₀Big more, the diameter of bubble is more little.According to the relation of the gas flow and the cross-section area of nozzle, can obtain the Reynolds number behind the variation:

${\mathrm{Re}}_0=\frac{4Q{\mathrm{\ρ}}_g}{{\mathrm{\πd}}_0{\mathrm{\μ}}_l}---\left(7\right)$

Q-gas flow in the formula

From (3) formula as can be seen, under certain winding-up tolerance, reduce nozzle inside diameter d ₀Can increase Reynolds number, enter the fluerics.So from gas permeable brick melting loss mechanism; when the slit refractory brick with tiny slit is blown reverse impact little, deteriorate for a short time, and mobile gas plays the cooling protection effect to refractory materials, it is even to be blown into gas distribution; can significantly reduce erosion, improve work-ing life refractory materials.Be other types refractory brick commonly used can't be obtained.

6, in desulfurization, make desulfurization product and be mingled with timely come-up and remove, thus cleaning molten steel.

Inclusion in the molten steel also is subjected to the effect of motion molten steel except that being subjected to buoyancy and gravity.The inclusion size is more little, and liquid motion is just obvious more to its influence.So for undersized inclusion, the state of liquid motion is the key factor of its removal effect of decision in the ladle.Fig. 6 is a bottom blowing ladle structural representation.

Bottom blowing is gone to be mingled with to go to be mingled with RH and is compared, no matter be from " Argon Bubble of come-up adheres to be suspended in the inclusion the molten steel and to bring to molten steel surface and absorbed by slag blanket " theory, still from " the stream thigh that makes progress drives inclusion, shortens its floating interval of floating dock " theory, the bottom blowing ladle removes to be mingled with and all is better than RH.Though RH is in the superiority that himself is arranged aspect the degassing, the smelting ultralow-carbon, its flow characteristics in ladle is unfavorable for the removal of inclusion very much.Experiment of RH water mould and Flow Field Calculation (as shown in Figure 8) result all show: have the many places whirlpool in the RH ladle.Impact after molten steel comes out from downtake and wrap at the end, the stream stock looses, and a part of stream thigh is met Bao Bihou, forms whirlpool near downtake, and some enters upcast and participates in the next round circulation.In the RH treating processes, because the existence of whirlpool has prolonged the inclusion floating time greatly, also some inclusion is inhaled into upcast, enters ladle afterwards again.

Molten steel just unavoidably can produce desulfurization product in sweetening process, so RH-PTB (as shown in Figure 1) has also increased the danger of polluting molten steel in desulfurization.Consider from purification of molten steel, be not suitable for desulfurization in the RH device.

7, mixing effect is than top-blown powder ideal.

The gas powder stream that sprays into also to the liquid acting, stirs molten steel except that participating in reaction.Wherein pulvis is compared with gas and can be ignored the stirring action of molten steel.This conclusion can be obtained by formula (4) (gas stirring energy density) and formula (5) (pulvis stirs energy density) simple computation.

$\mathrm{\ϵ}=\frac{R{T}_l{Q}_g}{V_N{M}_l}\{\ln \frac{p_1}{p_{\mathrm{atm}}}+\mathrm{\η}\·[(1-\frac{T_{g0}}{T_l})+\frac{T_{g0}}{T_l{p}_0}\left(\frac{1}{2}{\·\mathrm{\ρ}}_{g0}{{\·U}_{g0}}^2\right)+\frac{T_{g0}}{T_l}\ln \frac{p_{\mathrm{atm}}}{p_1}\left]\right\}---\left(8\right)$

${\mathrm{\ϵ}}_p=\frac{{\mathrm{\ρ}}_1{\mathrm{\ρ}}_g\mathrm{m\β}}{{\mathrm{\ρ}}_p{M}_l}[g{Q}_g+\frac{{{2Q}_g}^3}{(4+{\mathrm{\ρ}}_l/{\mathrm{\ρ}}_p){\mathrm{\π}}^2{d_0}^4}]---\left(9\right)$

ε in the formula-stirring can density T _l-fluid temperature Q _gThe volumetric flow rate of-gas

M _l-liquid mass P ₁-environmental stress η-stirring action effectiveness coefficient

ρ _G0-nozzle exit gas density T _G0-nozzle exit gas temperature

p ₀-nozzle exit gaseous tension U _G0The speed of-nozzle exit gas

ρ _l-fluid density ρ _g-gas density ρ _p-density of powder

M-solid-gas ratio β-penetration ratio d ₀-jet exit diameter

With winding-up CaC ₂Be example, suppose solid-gas ratio m=40, gas flow Q _g=0.021Nm ³/ h, penetration ratio β=0.5, substitution formula (8) and formula (9) calculating can learn that the ratio of gas and pulvis stirring energy density is about 100: 1, visible pulvis is very little to the influence of stirring energy, can ignore, so gas is occupied an leading position to the influence of stirring energy.But be blown into gas liquid is done work, comprises four aspects:

Work of expansion: gas does work owing to the temperature rising causes volumetric expansion near nozzle

Buoyancy merit: do work with expanding because of buoyancy in the bubble floating process

Power merit: the kinetic energy of gas streams acting during winding-up

The static pressure merit: remaining static pressure makes gas expansion for doing work during the gas ejection.

Because after air-flow comes out from spray gun in the top-blown powder device (as shown in Figure 8), also want downward retarded motion one segment distance, when speed was zero, bubble just began come-up.This just offsets the power merit is zero, and bottom blowing ladle (as shown in Figure 6) has then utilized the power merit fully.

Description of drawings

Fig. 1 is the RH-PTB synoptic diagram.Among the figure: 1 water cooled lance, 2 powders, 3 circulation gas.

Fig. 2 is a slit type ladle bottom blowing powder injection device synoptic diagram, 4 ladles among the figure, 5 slot-type ventilating bricks, 6 pipelines, 7 powder spraying pot systems.

Fig. 3 is a slot-type ventilating brick master TV structure synoptic diagram.

Fig. 4 is a slot-type ventilating brick plan structure synoptic diagram.

Fig. 5 constitutes synoptic diagram for the powder spraying pot system.

Among Fig. 5: 8 storage bunkers, 9 manual insertion plate doors, 10 feed valves, 11 pressure units, 12 powder spraying pots, 13 LOAD CELLS, 14 vaporizers, 15 blanking ball valves, 16 mixing sections, 17 electro connecting pressure gauges, 18 vent valves, 19 pressure release valves, 20 stopping valve, 21 vacuum breaker, 22 relief valves, 23 gas control shutoff valves.

Fig. 6 is a bottom blowing ladle structural representation

Fig. 7 is a RH flow field synoptic diagram

Fig. 8 is a top-blown powder device synoptic diagram

Embodiment

Embodiment 1 further describes slit type ladle bottom blowing powder injection device of the present invention, and embodiment 2～6 specifically describes the slit type ladle bottom blowing powder injection process of being implemented under distinct device parameter, the different technology conditions.

Embodiment 1

As shown in Figure 2, slit type ladle bottom blowing powder injection device of the present invention comprises slot-type ventilating brick 5, pipeline 6, powder spraying pot system 7.Slot-type ventilating brick 5 is installed in ladle 4 bottoms, and slot-type ventilating brick 5 is connected with powder spraying pot system 7 by pipeline 6.

Have the slit that an arrowhead distributes axisymmetricly in the middle of the slot-type ventilating brick, slit width should be limited in 0.1mm～0.3mm.

Powder spraying pot system 7 comprises 8 storage bunkers, 9 manual insertion plate doors, 10 feed valves, 11 pressure units, 12 powder spraying pots, 13 LOAD CELLS, 14 vaporizers, 15 blanking ball valves, 16 mixing sections, 17 electro connecting pressure gauges, 18 vent valves, 19 pressure release valves, 20 stopping valve, 21 vacuum breaker, 22 relief valves, 23 gas control shutoff valves, and storage bunker 8 bottoms are communicated with powder spraying pot 12 by manual insertion plate door 9 and feed valve 10; Powder spraying pot 12 tops are provided with pressure unit 11 and vent valve 18, pressure release valve 19; Powder spraying pot 12 sidewalls are equipped with LOAD CELLS 13, powder spraying pot 12 bottoms are vaporizers 14, vaporizer 14 is connected with mixing section 16 by blanking ball valve 15, be connected by pipeline between mixing section 16 and the electro connecting pressure gauge 17, vacuum breaker 21, stopping valve 20, gas control shutoff valve 23, relief valve 22, stopping valve 20 are installed on the pipeline successively; Powder spraying pot 12 tops are equipped with vacuum breaker 21 and are connected by pipeline with main line, and stopping valve 20, gas control shutoff valve 23 are installed on the pipeline successively; Vaporizer 14 is connected to vacuum breaker 21, is connected with main line by stopping valve 20.

The effect of following brief description powder spraying pot system 7 each several parts:

8 storage bunkers, material to be transported material leave in herein before entering powder spraying pot, and when opening feed valve, the material in the storage bunker constantly enters powder spraying pot, and when the material in powder spraying pot reached certain weight, Controlling System was closed feed valve.

9 manual insertion plate doors during the equipment load carrying, are opened manual insertion plate door, can adjust its aperture according to the blanking situation.

10 feed valves, feed valve are the key parts on the powder spraying pot.The principle of work of this valve is to drive coupking shaft by outer inside casing to do action up and down, thereby drives cone valve, when cone valve makes progress, promptly closes feed valve, when cone valve is downward, promptly opens feed valve.

11 pressure units are measured and demonstration powder spraying pot pressure, and give Controlling System signal feedback, and Controlling System is carried out the Adjustment System parameter with reference to this signal.

12 powder spraying pots are deposited the pressurized vessel of pulvis, for powder, are the main body of whole powder spraying system to delivery system.

13 LOAD CELLS show powder spraying pot weight in real time, by LOAD CELLS the powder spraying pot working condition are monitored.When the powder spraying pot charging, use it to control charging and guarantee that charging is reliable.

14 vaporizers carry out fluidisation to material, prevent that material from getting lodged in outlet.Gas is entered by the vaporizer side, during conveying the material that is transferred is carried out fluidisation, is beneficial to mass transport.

15 blanking ball valves are positioned at vaporizer bottom discharge mouth, and whether the major control material can enter transport pipe.

16 mixing sections, gas and powder mix at this, guarantee to carry uniform powder air-flow to gas permeable brick.

17 electro connecting pressure gauges are monitored total pipe pressure.

18 vent valves are positioned at the top of powder spraying pot, carry open after finishing vent valve quicken jar in pressure release, make charging smoothly and prevent that jar interior residual air from scurrying into the works better that top influences top equipment.

19 pressure release valves when the powder spraying pot internal pressure is excessive, excrete out pressure, the intravital pressure of stable can.

20 stopping valve for reply pneumatic control system burst accident, reasonably distribute tolerance, be provided with hand stop valve and regulate tolerance on each inlet pipe.

21 vacuum breaker prevent gas or powder airflow reflux.

22 relief valves, setting pressure in advance, both stable system pressure carried out overload protection to total system again.

23 gas control shutoff valves link to each other with housing by pipeline, are easy to the microcomputer Long-distance Control.

Embodiment 2

Cold conditions is implemented, and implementation condition is as follows:

Gas permeable brick: the slot-type ventilating brick that uses on 30 tons of ladles, gas permeable brick exit diameter 73mm, slit width 0.15mm, slit number are 18.

Powder: passive lime, particle diameter are all less than 45 μ m

Delivering gas: dried pressurized air

The speed of gas: 10m/s in the pipeline

Temperature: room temperature

Contact medium: atmosphere

Gaseous tension: 0.3MPa

Powder volume percentage: φ=0,10,20,30,40

Implementation process: present embodiment directly sprays gas powder stream in atmosphere, before dusting, open drainage gas earlier until arriving predetermined pressure 0.3MPa, then opening baiting valve begins to dust, after treating that the lime winding-up finishes, close baiting valve, drainage gas works on, and guarantees to close behind the noresidue lime in the pipeline drainage gas again.Regulate powder to air ratio by the gaseous tension in the adjustment powder spraying pot and the aperture of baiting valve in the implementation process, tested powder spraying system and slot-type ventilating brick serviceability under volume percentage φ=0,10,20,30 and 40 conditions.Do not find lime precipitation in the transfer lime in the implementation process, open the air chamber of gas permeable brick after the enforcement, do not find lime precipitation yet.

This illustrates that this process unit is feasible under the cold conditions situation.

Embodiment 3

Hot enforcement, implementation condition is as follows:

Gas permeable brick: the slot-type ventilating brick that uses on 30 tons of ladles, gas permeable brick exit diameter 73mm, slit width 0.15mm.In order to be adapted at working on the little induction furnace, the slit number of gas permeable brick is reduced to 8 by original 18.

Powder: carbon dust, particle diameter are all less than 30 μ m

Delivering gas: dried pressurized air

The speed of gas: 7m/s in the pipeline

Temperature: 1500 ℃

Contact medium: molten iron

Gaseous tension: 0.45MPa

The induction furnace of container: 200kg

Powder volume percentage: φ=10,30

Implementation process: the present embodiment carbon dust of in the induction furnace of the 200kg that molten iron is housed, jetting, before dusting, open drainage gas earlier until arriving predetermined pressure 0.45MPa, then opening baiting valve begins to dust, after treating that the carbon dust winding-up finishes, close baiting valve, drainage gas works on, and guarantees to close behind the noresidue carbon dust in the pipeline drainage gas again.Regulate powder to air ratio by the gaseous tension in the adjustment powder spraying pot and the aperture of baiting valve in the experimentation, tested volume percentage φ=10 and φ=30 time powder spraying system and the serviceability of slot-type ventilating brick under hot conditions.Do not observe the carbon dust deposition in the implementation process in the transfer lime, air chamber and the transfer lime implementing to check gas permeable brick in the back all do not have the carbon dust of discovery deposition.

Present embodiment illustrates that this process unit also is feasible under the condition of high temperature.

Embodiment 4

Hot enforcement, implementation condition is as follows:

Gas permeable brick: slot-type ventilating brick, gas permeable brick exit diameter 100mm, slit width 0.10mm, slit number are 16.

Powder: Na ₂CO ₃Pulvis, particle diameter are all less than 20 μ m

Delivering gas: industrial nitrogen

The speed of gas: 9m/s in the pipeline

Temperature: 1590 ℃

Contact medium: molten steel

Gaseous tension: 0.50MPa

Powder volume percentage: φ=10,20,30,40

Implementation process: present embodiment sprays gas powder stream in the induction furnace that the 100kg molten steel is housed, and before dusting, opens drainage gas earlier until arriving predetermined pressure 0.50MPa, then opens baiting valve and begins to dust, and treats Na ₂CO ₃After winding-up finishes, close baiting valve, drainage gas works on, and guarantees noresidue Na in the pipeline ₂CO ₃After close drainage gas again.Regulate powder to air ratio by the gaseous tension in the adjustment powder spraying pot and the aperture of baiting valve in the implementation process, tested powder spraying system and slot-type ventilating brick serviceability under volume percentage φ=10,20,30 and 40 conditions.Do not find Na in the transfer lime in the implementation process ₂CO ₃Deposit, open the air chamber of gas permeable brick after the enforcement, also do not find Na ₂CO ₃Deposition.

As long as meeting the solid particulate of injection parameters, the present embodiment explanation may be used to winding-up.

Embodiment 5

Hot enforcement, implementation condition is as follows:

Gas permeable brick: slot-type ventilating brick, gas permeable brick exit diameter 150mm, slit width 0.25mm, slit number are 24.

Powder: CaSi alloy powder, particle diameter are all less than 50 μ m

Delivering gas: industrial nitrogen

The speed of gas: 9.5m/s in the pipeline

Temperature: 1470 ℃

Contact medium: molten iron

Gaseous tension: 0.51MPa

Powder volume percentage: φ=15,25,35,40

Implementation process: present embodiment sprays gas powder stream in the induction furnace that the 100kg molten iron is housed, before dusting, open drainage gas earlier until arriving predetermined pressure 0.51MPa, then opening baiting valve begins to dust, after treating that the winding-up of CaSi powder finishes, close baiting valve, drainage gas works on, and guarantees to close drainage gas again behind the noresidue CaSi powder in the pipeline.Regulate powder to air ratio by the gaseous tension in the adjustment powder spraying pot and the aperture of baiting valve in the implementation process, tested powder spraying system and slot-type ventilating brick serviceability under volume percentage φ=15,25,35 and 40 conditions.Do not find CaSi powder deposition in the transfer lime in the implementation process, open the air chamber of gas permeable brick after the enforcement, do not find CaSi powder deposition yet.

Embodiment 6

Hot enforcement, implementation condition is as follows:

Gas permeable brick: slot-type ventilating brick, gas permeable brick exit diameter 40mm, slit width 0.12mm, slit number are 7.

Powder: passive lime, particle diameter are all less than 30 μ m

Delivering gas: dried pressurized air

The speed of gas: 8.2m/s in the pipeline

Temperature: 1600 ℃

Contact medium: molten steel

Gaseous tension: 0.53MPa

Powder volume percentage: φ=10,20,30,40

Implementation process: present embodiment sprays gas powder stream in the induction furnace that the 150kg molten steel is housed, before dusting, open drainage gas earlier until arriving predetermined pressure 0.53MPa, then opening baiting valve begins to dust, after treating that the lime winding-up finishes, close baiting valve, drainage gas works on, and guarantees to close behind the noresidue lime in the pipeline drainage gas again.Regulate powder to air ratio by the gaseous tension in the adjustment powder spraying pot and the aperture of baiting valve in the implementation process, tested powder spraying system and slot-type ventilating brick serviceability under volume percentage φ=10,20,30 and 40 conditions.Do not find lime precipitation in the transfer lime in the implementation process, open the air chamber of gas permeable brick after the enforcement, do not find lime precipitation yet.

Claims (8)

1, slit type ladle bottom blowing powder injection process, it is characterized in that carrying fluidised pulvis to slot-type ventilating brick by the powder spraying pot system, by slot-type ventilating brick pulvis is sprayed into the molten steel from ladle bottom again, concrete winding-up process is: powder is delivered into powder spraying pot (12) from storage bunker (8), after adding powder, begin the pressurization of in powder spraying pot (12), supplying gas, the gas control shutoff valve (23) of control drainage gas is opened, drainage gas is started working, open the fluidizing agent in the vaporizer (14) then, open the blanking ball valve (15) of powder spraying pot lower part outlet at last, the action that begins to dust is transported to gas permeable brick with powder, and powder enters the air chamber of gas permeable brick, slit is given in reallocation, arrives in the molten steel by slit.

2,, it is characterized in that injection parameters is as follows according to the described slit type ladle bottom blowing powder injection process of claim 1:

(1) parameter request of pulvis:

1. particle diameter d _p≤ 0.2r

D in the formula _p-pulvis diameter r-slit width

2. pulvis is a solid particulate

The powder to air ratio parameter request:

Require the powder fraction by volume $\mathrm{\φ}=\frac{V_p}{V_{\mathrm{mix}}}\≤0.6$

φ in the formula-fraction by volume V _pThe volume V of-powder _MixThe cumulative volume of-powder and gas

(2) carrier gas requires:

1. the speed V of the interior gas of pipeline is greater than the critical fluidization velocity V of powder _Mf, promptly

$V>V_{\mathrm{mf}}=\frac{(1-{\mathrm{\ϵ}}_{\mathrm{mf}})({\mathrm{\ρ}}_p-{\mathrm{\ρ}}_g)}{150\frac{{(1-{\mathrm{\ϵ}}_{\mathrm{mf}})}^2\mathrm{\μ}}{{{\mathrm{\ϵ}}_{\mathrm{mf}}}^2{\left({\mathrm{\φ}}_s\stackrel{\‾}{d_p}\right)}^2}+1.75\frac{1-{\mathrm{\ϵ}}_{\mathrm{mf}}}{{{\mathrm{\ϵ}}_{\mathrm{mf}}}^2}\·\frac{{\mathrm{\ρ}}_g}{{\mathrm{\φ}}_s\stackrel{\‾}{d_p}}}$

Gas velocity V in the V-transfer lime in the formula _Mf-critical fluidization velocity ε _Mf-critical voidage

ρ _p-pellet density ρ _g-gas density μ-gas viscosity

φ _s-sphericity The mean diameter of-pulvis

2. gas flow satisfies following formula:

$Q>\frac{2100{\mathrm{\πd}}_0{\mathrm{\μ}}_l}{{4\mathrm{\ρ}}_g}$

Q-gas flow d in the formula ₀-nozzle inside diameter

ρ _gThe density μ of-gas _LThe viscosity of-liquid.

3, according to the described slit type ladle bottom blowing powder injection process of claim 1, it is characterized in that delivering gas is dried gas, gaseous tension is 0.30～0.7MPa.

4, according to the described slit type ladle bottom blowing powder injection process of claim 1, it is characterized in that adopting dilute phase intermittent delivery mode of operation, every conveying one pump material, be a working cycle, each working cycle comprises the conveying initial period, delivery phase, carry ending phase, after carrying beginning, material in the powder spraying pot is brought into pipeline by air-flow, and the material in the pipeline increases, and the operating pressure of powder spraying pot increases, this process is for carrying initial period, when the constant delivery phase that promptly enters of operating pressure maintenance of powder spraying pot, along with material in the jar reduces, the operating pressure of powder spraying pot reduces, enter purge stages this moment, promptly carries ending phase.

5,, it is characterized in that pulvis is that diameter meets d according to the described slit type ladle bottom blowing powder injection process of claim 1 _pThe solid particulate of≤0.2r comprises passive lime, carbon dust, Na ₂CO ₃Pulvis or CaSi alloy powder.

6, the slit type ladle bottom blowing powder injection device of the described process using of claim 1, it is characterized in that this device comprises slot-type ventilating brick (5), pipeline (6), powder spraying pot system (7), slot-type ventilating brick (5) is installed in ladle (4) bottom, and slot-type ventilating brick (5) is connected with powder spraying pot system (7) by pipeline (6).

7, according to the described slit type ladle bottom blowing powder injection device of claim 6, it is characterized in that having the slit that an arrowhead distributes axisymmetricly in the middle of the slot-type ventilating brick, slit width is limited in 0.1mm～0.3mm.

8, according to the described slit type ladle bottom blowing powder injection device of claim 6, it is characterized in that powder spraying pot system (7) comprises storage bunker (8), pressure unit (11), powder spraying pot (12), LOAD CELLS (13), vaporizer (14), mixing section (16), storage bunker (8) bottom is communicated with powder spraying pot (12) by manual insertion plate door (9) and feed valve (10); Powder spraying pot (12) top is provided with pressure unit (11) and vent valve (18), pressure release valve (19); Powder spraying pot (12) sidewall is equipped with LOAD CELLS (13), powder spraying pot (12) bottom is vaporizer (14), vaporizer (14) is connected with mixing section (16) by blanking ball valve (15), be connected by pipeline between mixing section (16) and the electro connecting pressure gauge (17), vacuum breaker (21), stopping valve (20), gas control shutoff valve (23), relief valve (22), stopping valve (20) are installed on the pipeline successively; Powder spraying pot (12) top is equipped with vacuum breaker (21) and is connected by pipeline with main line, and stopping valve (20), gas control shutoff valve (23) are installed on the pipeline successively; Vaporizer (14) is connected to vacuum breaker (21), is connected with main line by stopping valve (20).

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