Of firebrick of cement rotary kiln erode mechanism and protection

March 15, 2024Nov 25, 2024

Of the firebrick inside cement rotary kiln erode mechanism
The main effect of rotary kiln firebrick is the harm that protects kiln cylindrical shell not to get high temperature gas and high temperature stock, assure manufacturing on the rails. In industrial production, firing the service life that leads firebrick is very brief, kiln overhaul stops outside often causing a plan, it is influence cement kiln high quality, high yield, low cost is mixed the crucial factor of year of movement rate.
No matter be wet kiln, still be new-style rotary kiln working a way, in process of clinker to calcine, because body temperature is enraged inside kiln,get higher than stock temperature much, kiln every rotate circuit, kiln line surface gets periodic thermal shock, temperature change extent is 150~250 ℃ , thermal stress arises inside limits of surface layer of kiln line 10~20mm.
The radial that the system of bricky build by laying bricks or stones that kiln line still bears to arise as a result of the whirl of kiln changes alternately and axial machinery stress, and of to calcine stock erode wear away. Because produce silicate fuse-element at the same time, form initiative layer very easily below high temperature environment with interaction of surface of kiln line firebrick, arrive along the hole infiltration of firebrick at the same time the interior of firebrick, be together with firebrick felt, make the chemical composition inside limits of 10~20mm of firebrick surface layer and photograph composition produce change, reduce the specifications of firebrick.


The agglomeration range when stock is narrower perhaps form short blaze to burn generation urgently when local high temperature, can make the photograph of fluid of stock of temperature prep above of kiln skin surface caky temperature, layer of kiln skin surface turns into from solid state namely liquid state and fall off, and reach li of development by the watch to kiln skin initiative hind form new kiln skin again initiative layer. When this kind of case appears repeatedly, firing the line that bring pit gradually by thick attenuate, fall off completely even, bring about local show kiln cylindrical shell and red kiln.
Actually firing absolutely of circumstance of attaint of the line that bring pit, the arc with curvature bigger radius is shown to distributing in substantially of ply of brick of incomplete of high temperature area, fall in kiln cylindrical shell by arc sometimes inside apparently.

 

How to undertake protective to the firebrick inside cement rotary kiln
1. fights broken bits sex is the ability that shows fireproof material resists chemistry is eroded, forming kiln skin initiative layer and when stock agglutinant big or produce local heat preservation to make kiln skin fall off below the circumstance, the sex that fight broken bits appears very important.
Interstitial rate reachs thermal conductance, initiative to forming kiln skin layer is having very main effect, and be in kiln skin is local when falling off, what hole is led and the fireproof stuff with older thermal conductance conduces to kiln skin is seasonable fill hang. But show huge to destroy effect likely again at the same time, the layer that makes firebrick comes off falls off.
2. firebrick is in its production process, its change physico-chemically to was not achieved commonly firing the balance position below temperature. Also have firing inadequate firebrick, suffer again in rotary kiln action consequently when high temperature action, most firebrick reachs the fill of hole as a result of the generation of photograph of main body fluid, happen not reversible burn systole again. Accordingly, stability of high temperature bulk is in choose firing when taking firebrick, give consideration.
Heating up exterior layer shape to come off is rotary kiln firing the main form of the attaint after the line that bring pit experiences thermal shock; If skin of coinstantaneous local kiln falls off, can make firebrick service life shortens greatly.
When 3. makes fuel with coal, the volatilization of coal is divided and ash content is having conclusive effect, affect blaze figure directly. Volatilize the coal fines with component is higher and inferior ash content, but nigrify flame shortens, form microtherm to grow blaze to calcine. It is advantageous commonly to protecting kiln line, but volatilize cent is exorbitant, catch fire too fast, temperature of exert kiln grog is as high as 260 ℃ above, 2 times wind Wen Chao crosses 900 ℃ , extremely easy burned-out nozzle, make its are out of shape or burn broken occurrence breach, produce disorder blaze figure, damaged kiln line before its are changed. The volatilization of coal has assigned low, ash content too tall (be more than 28% ) , the incomplete combustion of a large number of coal fines can sedimentation burn inside stock and give off much heat to also can injure kiln skin.
Aborning of structure of 4. fuel burner often did not get enough attention, nozzle appearance and exit dimension basically affect coal fines same the mixture degree of second wind and ejective speed, it is those who strengthen wind coal to mix sometimes, still can add the wing that install wind inside nozzle, but should notice to come back shed wind to rotate extent crosses congress to sweep kiln skin.
5. is led when aluminium exorbitant, when fluid photograph viscosity is big, kiln skin breaks down in great quantities fall, on the operation not easy control, adverse to protecting kiln line, in producing practice, aluminous rate is controlled commonly in 1.3~1.6; Should adopt tall saturation to compare, easy generation is sticky when Gao Gui rate, low fluid expects suitably medicinal powder makings erode, abrasion kiln skin makes pit small serious when scathing kiln line, the silicon in producing practice 2.5 when, saturation comparing exceeds 0.92 not easily, lead when silicon 2.8 when, saturation comparing exceeds 0.9 not easily.
The wave motion that 6. raw material feeds makings volume is bigger to the harm of kiln line. When the supplied materials inside kiln is too much, must close small pit end to discharge wind force, increase coal fines dosage to undertake forcing fire is burned by force, make firing take thermic load mushroom, make kiln line is damaged badly. Become when the supplied materials inside kiln is too little, coal fines blaze is apparent declination, the kiln skin of this area can fall off below high temperature, attenuate, the makings layer with thinner go at, if be moved not in time,measure with coal, skin of extremely easy burned-out kiln and firebrick. Additional, the wave motion that raw material feeds makings volume can cause system of industry of the heat inside kiln again not stable, temperature is too big, make kiln skin falls off or be damaged.
Accordingly, be as high as 1260 ℃ above when temperature of grog giving pit, when 2 times wind Wen Chao crosses 900 ℃ , extremely easy burned-out nozzle, make its are out of shape or burn broken occurrence breach, produce disorder blaze figure, make kiln line damages extremely easily. 3 rate value controls clinker commonly in KH0.91 ± 0.01, silicon leads 2.6 ± 0.1, aluminous rate control is between 1.3~1.6, to protecting firebrick service life is mixed increase clinker strength extremely good part.

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