CN117450779A - Method for quickly adjusting kiln of metallurgical rotary kiln - Google Patents
Method for quickly adjusting kiln of metallurgical rotary kiln Download PDFInfo
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- CN117450779A CN117450779A CN202311617812.6A CN202311617812A CN117450779A CN 117450779 A CN117450779 A CN 117450779A CN 202311617812 A CN202311617812 A CN 202311617812A CN 117450779 A CN117450779 A CN 117450779A
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- 238000000034 method Methods 0.000 title claims abstract description 48
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 43
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 36
- 238000004519 manufacturing process Methods 0.000 claims abstract description 29
- 230000008569 process Effects 0.000 claims abstract description 22
- 239000003575 carbonaceous material Substances 0.000 claims abstract description 19
- 238000012360 testing method Methods 0.000 claims abstract description 19
- 230000007246 mechanism Effects 0.000 claims abstract description 5
- 239000002994 raw material Substances 0.000 claims description 50
- 239000000463 material Substances 0.000 claims description 47
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 38
- 239000003245 coal Substances 0.000 claims description 26
- 239000007789 gas Substances 0.000 claims description 22
- 239000003546 flue gas Substances 0.000 claims description 12
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 11
- 238000007599 discharging Methods 0.000 claims description 10
- 239000000428 dust Substances 0.000 claims description 9
- 238000002347 injection Methods 0.000 claims description 9
- 239000007924 injection Substances 0.000 claims description 9
- 238000009826 distribution Methods 0.000 claims description 7
- 238000006722 reduction reaction Methods 0.000 claims description 7
- 238000011049 filling Methods 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 5
- 238000005303 weighing Methods 0.000 claims description 5
- 230000008859 change Effects 0.000 claims description 4
- 239000000779 smoke Substances 0.000 claims description 3
- 230000009467 reduction Effects 0.000 abstract description 2
- 238000002485 combustion reaction Methods 0.000 description 11
- 238000006243 chemical reaction Methods 0.000 description 10
- 238000013461 design Methods 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 239000008188 pellet Substances 0.000 description 4
- 238000001816 cooling Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 239000002893 slag Substances 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 2
- 230000000740 bleeding effect Effects 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 238000002309 gasification Methods 0.000 description 2
- 239000006148 magnetic separator Substances 0.000 description 2
- 230000001360 synchronised effect Effects 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 238000004177 carbon cycle Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000011900 installation process Methods 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000001465 metallisation Methods 0.000 description 1
- 238000010310 metallurgical process Methods 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000007363 ring formation reaction Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B7/00—Rotary-drum furnaces, i.e. horizontal or slightly inclined
- F27B7/20—Details, accessories, or equipment peculiar to rotary-drum furnaces
- F27B7/42—Arrangement of controlling, monitoring, alarm or like devices
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Muffle Furnaces And Rotary Kilns (AREA)
Abstract
The invention discloses a method for quickly adjusting kiln of a metallurgical rotary kiln, which uses carbon materials to burn in the kiln to supply heat to develop a blank test, can quickly determine an optimal air supply structure corresponding to a required production temperature curve, and simultaneously calibrates key process parameters such as minimum carbon circulation base number, air supply quantity and the like. And by utilizing the thermal engineering characteristics and metallurgical reduction mechanism of the metallurgical rotary kiln, the actual maximum capacity of the rotary kiln can be calibrated and proper technological parameters can be found through deduction calculation and carrying out a belt test, and the rotary kiln can be adjusted to a full-load stable state in a short time.
Description
Technical Field
The invention belongs to the technical field of ore processing and metallurgy, and relates to a method for quickly adjusting a kiln of a metallurgical rotary kiln.
Background
The kiln adjustment of the rotary kiln refers to the process of adjusting various process parameters of the rotary kiln to the maximum capacity steady state. The rotary kiln production line has to carry out kiln adjustment before being built and put into production, and when the rotary kiln is changed in process, switched in products, greatly modified and even stopped in accident, kiln adjustment is carried out again, and the best production state of the metallurgical rotary kiln cannot be achieved without kiln adjustment. Because of the serial metallurgical reactions in the production process of the metallurgical rotary kiln, the metallurgical rotary kiln has complex structure, more parameters and more interference factors, and has high kiln adjustment operation difficulty. Kiln adjustment not only requires specialized knowledge and abundant experience, but also requires a long time and high cost. Improper kiln adjustment is light, which leads to production line failure and failure to reach standard, and serious damage to equipment and causes various accidents, thereby causing larger loss, and kiln adjustment is a necessary and important work for the metallurgical rotary kiln, but is a very difficult work at the same time.
The traditional kiln regulating method of the metallurgical rotary kiln generally comprises the steps of heating the rotary kiln to a high temperature state according to a kiln drying curve, and then starting with a small material amount according to production line design data or artificial experience, and starting with trial feeding according to a certain formula and parameters. After feeding, various parameters are required to be continuously adjusted at any time according to the state and the discharging condition of the rotary kiln until the rotary kiln reaches a stable state suitable for the feeding amount. After reaching a certain stable state, gradually increasing the feeding amount, then adjusting, re-adapting and re-stabilizing, and thus, repeatedly searching the maximum productivity and proper technological parameters of the rotary kiln. The process is simple, is difficult to practice, is easy to oversand undersize in the kiln adjustment process, often does not start production, and can be started again for feeding after accident treatment because the conditions such as liquid leakage, kiln cooling and the like are forced to stop. The kiln adjustment process takes a few months and a plurality of years, and a large amount of manpower and material resources are consumed in the kiln adjustment process, so that the cost is high, and the final effect is unsatisfactory.
All such difficulties in the kiln adjustment process of metallurgical rotary kilns are mainly caused by the following reasons: firstly, the metallurgical rotary kiln system inevitably has some errors, defects and mismatch in the design, manufacturing and construction processes, the system design data always has a certain difference from the actual situation, the data can only be used as a reference and cannot be directly used, and only the data actually calibrated on site really has a use value. Secondly, the manual experience often varies from person to person, lacks theoretical support, kiln adjustment operation is not systematic and accurate, related experience is limited by a plurality of specific conditions, and the reason cannot be judged and proper measures can be taken to correct after deviation or abnormal conditions occur; thirdly, the metallurgical rotary kiln has a complex structure, a great number of parameters needing synchronous adjustment, and the parameters have strong coupling property, poor linear relation and great difficulty in synchronous adjustment due to series metallurgical reactions. Fourth, the inherent large hysteresis characteristics of the rotary kiln and the actual various interference factors further increase the difficulty of adjustment. Therefore, the traditional kiln adjustment has long time, high cost and poor effect, and the problems not only severely restrict the production of the metallurgical rotary kiln, but also prevent the development of the metallurgical process taking the rotary kiln as main process equipment.
Disclosure of Invention
In order to solve the problem of difficult kiln adjustment of the metallurgical rotary kiln, the invention provides a method for quickly adjusting kiln of the metallurgical rotary kiln, which uses carbon materials to burn in the kiln to supply heat to develop a blank test, can quickly determine an optimal air supply structure corresponding to a required production temperature curve, and simultaneously calibrates key process parameters such as minimum carbon circulation base number, air supply quantity and the like. And by utilizing the thermal engineering characteristics and metallurgical reduction mechanism of the metallurgical rotary kiln, the actual maximum capacity of the rotary kiln can be calibrated and proper technological parameters can be found through deduction calculation and carrying out a belt test, and the rotary kiln can be adjusted to a full-load stable state in a short time.
In order to achieve the above purpose, the invention adopts the following technical scheme:
the method for quickly adjusting the kiln of the metallurgical rotary kiln comprises the following steps of using a metallurgical rotary kiln system, wherein the metallurgical rotary kiln system comprises a rotary kiln, a raw material conveying system and a flue gas dust removal system are connected to the kiln tail of the rotary kiln, and a kiln tail induced draft fan is arranged at the tail end of the flue gas dust removal system; the kiln back of the rotary kiln is provided with at least one kiln backup fan, the kiln head of the rotary kiln is connected with a granular coal injection system, an air supply Roots fan, a gas burner and a finished product discharging system, and the gas burner is also connected with a combustion-supporting fan; characterized in that the method comprises the steps of:
step one: starting the rotary kiln to enable the rotary kiln to normally operate at a rotating speed of 0.1-0.5 r/min, adding carbon materials into the kiln from the tail of the kiln by using a belt scale and conveying equipment at the moment, enabling the carbon materials to build a neat material layer and normally travel until the kiln head is discharged; the dip angle of the material layer is kept between 15 degrees and 45 degrees;
step two: igniting carbon materials of the whole kiln by using a gas burner, heating the rotary kiln to 600-1200 ℃, wherein the temperature of kiln tail smoke is 500-700 ℃, the temperature of kiln head cover is less than or equal to 900 ℃, the pressure of kiln head is-20 to +20Pa, and the pressure of kiln tail is-10 to-120 Pa; observing the condition of the materials in the kiln during the period, so that the filling rate of the materials in the kiln is always more than or equal to 10%;
step three: the wind power of a kiln tail induced draft fan, the wind power of a wind supply Roots blower, the wind power of a kiln back blower, the wind power of a combustion-supporting blower and the opening degree of a kiln door are adjusted to form different wind supply structures, and a blank test is developed; testing the change rules of kiln temperature distribution and kiln pressure under various different air supply structures, analyzing and comparing experimental data, and summarizing the relation between the air supply structures and kiln temperature curves; the priority order of the air supply structure adjustment is as follows: kiln back fan > air supply Roots fan > combustion supporting fan > kiln tail induced draft fan > other;
step four: adjusting the air supply structure and the air supply quantity to ensure that the kiln temperature curve of the rotary kiln is consistent with the curve required by the production process and reaches a stable state for more than 1 hour;
step five: the carbon consumption required by maintaining the current kiln temperature curve in an empty kiln state, namely the minimum carbon circulation base number, is calculated by weighing the carbon residue, the air supply quantity corresponding to the current air supply structure is recorded, and according to the thermal engineering characteristics of the rotary kiln, the carbon consumption and the air supply quantity at the moment correspond to 30% -40% of the full load of the rotary kiln, so that the iron oxide raw material quantity corresponding to the air supply quantity can be calculated based on the carbon consumption and the air supply quantity;
step six: the air supply structure and the air supply quantity are kept unchanged, iron oxide raw materials are added from the kiln tail, and the carbon quantity is increased, so that the kiln temperature curve is basically consistent with a blank test; according to the thermal engineering characteristics of the rotary kiln and the mechanism of metallurgical reduction reaction, because the air supply structure and the air quantity are kept unchanged, the rotary kiln can reach 60% -80% of full load at the moment, so that the iron oxide raw material quantity of the rotary kiln at 100% of full load, namely the maximum productivity reference value, can be calculated according to the material quantity;
step seven: gradually increasing the iron oxide raw material amount according to the iron oxide raw material amount reference value calculated in the step six when the rotary kiln is fully loaded, stopping increasing the raw material amount when the raw material amount is increased until the rotary kiln is fully cooled, a high temperature zone is continuously moved or a certain parameter of the system reaches the upper limit, and recovering the last stable state, wherein the actual material amount is the actual maximum capacity of the rotary kiln, and recording the current process parameter value as the full-load stable state parameter.
The kiln adjusting principle of the invention is as follows:
the blank test is carried out by using the carbon material to eliminate the influence of the conditions of material adhesion, ring formation and the like caused by material hot melting on the calibration result by utilizing the high melting point characteristic of the carbon, and simultaneously, the interference of volatile matters, impurities and the like can be reduced to the greatest extent. When the carbon material is used for blank test, the atmosphere and the environment in the kiln are relatively single, and mainly the fuel combustion is used for heating so as to heat the rotary kiln and the flue gas. The chemical reaction mainly comprises gasification and combustion of carbon, wherein 50% of oxygen in air supply in the rotary kiln is used for producing CO by reacting with carbon, and 50% is used for supporting combustion of CO to produce CO 2 . According to the experience of thermal engineering, the thermal load required by using fuel to maintain a normal kiln temperature curve in an empty kiln state of a metallurgical kiln is 30% -40% of the full load, that is to say, the minimum air volume calibrated at the moment of a blank test is 30% -40% of the air volume required by the full load, and the air supply is totally used for being in reverse with C at the momentTherefore, the air supply quantity at the moment can be accurately calculated according to the carbon consumption, and the calibration result is not influenced by system errors. The main reaction equation is as follows:
O 2 +2C→2CO
CO 2 +C→2CO
2CO+O 2 →2CO 2
under the condition of keeping the air supply structure and the air quantity unchanged, the raw material is added into the kiln again, and at the moment, the contact area of the raw material is obviously larger than O due to the direct contact of the raw material and C 2 The contact area with the material layer surface C, so that CO in the kiln is converted from O 2 Gasification production is converted to metallurgical reduction reaction production, and the latter production is much greater than the former. Due to the selective nature of the chemical reaction, O 2 The CO gas which is easier to react is firstly selected to carry out combustion reaction, and when the CO is completely combusted, the redundant O 2 It is possible to react with C. O in the kiln as the feedstock travels 2 Will soon become totally reacted with CO to generate CO 2 CO in flue gas 2 Will continue to gasify C to produce CO, a portion of which is used to form O 2 The reaction burns to supply heat, and part of the heat is used for reducing the iron oxide raw material to continuously produce CO 2 This is cycled back and forth, and a series of metallurgical reactions occur. The main chemical reaction equation is as follows:
3Fe 2 O 3 +C→2Fe 3 0 4 +CO
Fe 3 O 4 +C→3FeO+CO
Fe 3 O 4 +4C→3Fe+4CO
2FeO+2C→2Fe+2CO
3Fe 2 O 3 +CO→2Fe 3 0 4 +CO 2
Fe 3 O 4 +CO=3FeO+CO 2
FeO+CO→Fe+CO 2
CO 2 +C→2CO
2CO+O 2 →2CO 2
as can be seen from the above equation, the metallurgical reduction reaction is continuously enhanced and increased along with the continuous increase of the material amount after feedingThe heat released by the combustion of CO generated by the method not only can offset the influence of heat absorption of the cooling material, but also can support the heat required by the metallurgical reaction until a heat balance point is reached. The material amount at this time is the maximum material amount supported by the air quantity of the air supply structure. Since the air quantity is unchanged at this time, 50% of the original O used for gasifying carbon 2 The method is characterized in that the method is used for generating CO through combustion-supporting metallurgical reaction, the gas amount generated at the moment is doubled compared with that of a blank test, so that the calculation is carried out according to 30% -40% of heat load of the blank kiln, the steady state at the moment corresponds to 60% -80% of heat load of the maximum energy production of the rotary kiln, and the material amount also corresponds to 60% -80% of energy production material amount.
According to the 60% -80% full load maximum energy production amount calibrated by the belt material test, the reference value of 100% full load amount and the corresponding set value of parameters such as a fan, an air pipe valve and the like can be calculated. According to these references, it is usually only necessary to adjust the mass to full load very quickly, with 2-3 times. The adjustment method and principle are also to take the air supply structure as the adjusting main line, and at the same time, maintain enough carbon residue. Therefore, the full-load maximum capacity of the rotary kiln and the calibration of corresponding steady-state process parameters can be completed quickly only by adjusting in a smaller material amount range and only when the upper limit of the system is reached and the material amount can not be increased continuously.
The beneficial effects of the invention are as follows:
(1) Compared with the traditional kiln adjustment time which is as long as several months, the method can shorten the kiln adjustment time to be within 1 week, and has the advantages of high efficiency, short time, good effect and economy.
(2) The method gets rid of possible deviation and defects of the rotary kiln system in the design, manufacture and installation processes by using the test method, also reduces the influence of on-site actual comprehensive factors to the greatest extent, and the kiln temperature curve is more in accordance with the requirements of the actual production process, and the adjustment result is accurate and stable.
(3) The method has the advantages of simple steps and convenient operation, and the used devices and instrument equipment are common equipment of the metallurgical rotary kiln, so that the method does not need to modify the original production line and add additional measuring equipment, and is easy to popularize and implement.
(4) The thought and the method related to the adjustment of the technological parameters can be applied to various production scenes, can be used for not only the whole production process of kiln starting, production and kiln stopping, but also the emergency treatment under the condition of guiding various abnormal halts.
(5) In the implementation process of the invention, the carbon is always sufficient, SO that the kiln is always in a reducing atmosphere, sulfur in the raw material cannot be oxidized into SO2 gas, the problem of exceeding SO2 standard which cannot be avoided in the traditional kiln adjustment process is solved, and the adjustment process is completely environment-friendly.
Drawings
FIG. 1 is a process flow diagram of the present invention.
FIG. 2 is a schematic diagram of a metallurgical rotary kiln system employed in the method of the present invention.
In the figure, a 1-raw material bin, a 2-raw material belt scale, a 3-carbon bin, a 4-carbon belt scale, a 5-raw material belt conveyor, a 6-roller granulator, a 7-feeding belt conveyor, an 8-rotary kiln, a 9-kiln back fan, a 10-gas burner, an 11-combustion fan, a 12-air supply Roots fan, a 13-coal throwing Roots fan, a 14-coal bin, a 15-quantitative feeder, a 16-roller slag cooler, a 17-finished product belt conveyor, an 18-dry magnetic separator, a 19-flue gas dust removal system and a 20-kiln tail induced draft fan.
Detailed Description
The invention is further illustrated by the following description in conjunction with the accompanying drawings and specific embodiments.
As shown in fig. 2, a metallurgical rotary kiln system comprises a rotary kiln 8, wherein a raw material conveying system and a flue gas dust removal system are connected to the kiln tail of the rotary kiln 8, and a kiln tail induced draft fan 20 is arranged at the tail end of the flue gas dust removal system; the kiln back of the rotary kiln 8 is at least provided with a kiln backup fan 9, the kiln head of the rotary kiln 8 is connected with a granular coal injection system, an air supply Roots fan 12, a gas burner 10 and a finished product discharging system, and the gas burner 10 is also connected with a combustion-supporting fan 11.
The raw material conveying system comprises a raw material bin 1 and a carbon bin 3, wherein the bottoms of the raw material bin 1 and the carbon bin 3 are respectively and correspondingly provided with a raw material belt balance 2 and a carbon material belt balance 4, a raw material belt conveyor 5 is arranged below the raw material belt balance 2 and the carbon material belt balance 4, the raw material belt conveyor 5 is connected with the feeding end of a roller granulator 6, a feeding belt conveyor 7 is arranged below the discharging end of the roller granulator 6, and the feeding belt conveyor 7 is connected with the kiln tail of a rotary kiln 8.
The flue gas dust removal system adopts an ultralow emission system for flue gas desulfurization, dust removal and denitration of a lime rotary kiln disclosed in the prior art CN 202020893816.2.
The pellet coal injection system comprises a pellet coal bin 14, a doser 15 is connected to the bottom of the pellet coal bin 14, the doser 15 is connected with the kiln head of the rotary kiln 8 through a pipeline, and a coal throwing Roots blower 13 is further arranged on a connecting pipeline between the doser 15 and the rotary kiln 8.
The finished product material discharging system comprises a roller slag cooler 16 connected with the discharging end of the kiln head of the rotary kiln 8, a finished product belt conveyor 17 is arranged below the roller slag cooler 16, and the tail end of the finished product belt conveyor 17 is connected with a dry magnetic separator 18.
Weighing carbon materials and raw materials by using a raw material belt scale 2 and a carbon material belt scale 4, granulating the weighed materials by adopting a roller granulator 6, adding the materials into a rotary kiln 8 from a kiln tail chute by adopting a feeding belt conveyor 7, sintering the materials into finished products in the kiln through a high-temperature metallurgical reduction reaction, discharging the finished products from a kiln head, and finally cooling and sorting to obtain finished product materials. The kiln head of the rotary kiln is provided with a gas burner 10 and a granular coal injection system, and the middle and front area of the rotary kiln is provided with 3 kiln back fans to form a secondary air supply system. The granular coal injection system uses Roots blower to supply air, the kiln lee blower 9 and the combustion-supporting blower 11 of the burner nozzle adopt centrifugal blower to supply air, and the kiln hood is also provided with a kiln door which can be opened and closed. The kiln head and the kiln tail of the rotary kiln 8 are provided with fixed pressure and temperature meters, and the kiln body is also provided with a plurality of inserted thermocouples for transmitting temperature signals into a monitoring system. In addition, a handheld thermometer is used for measuring the temperature of the kiln cover at intervals of 3-5 m to master the distribution condition of the temperature curve of the rotary kiln.
As shown in fig. 1, a kiln adjustment method adopting the metallurgical rotary system comprises the following steps:
step one: starting the rotary kiln to enable the rotary kiln to normally operate at a rotating speed of 0.1-0.5 r/min, adding carbon materials into the kiln from the tail of the kiln by using a belt scale and conveying equipment at the moment, enabling the carbon materials to build a neat material layer and normally travel until the kiln head is discharged; the dip angle of the material layer is kept between 15 degrees and 45 degrees;
step two: igniting carbon materials of the whole kiln by using a gas burner, heating the rotary kiln to 600-1200 ℃, wherein the temperature of kiln tail smoke is 500-700 ℃, the temperature of kiln head cover is less than or equal to 900 ℃, the pressure of kiln head is-20 to +20Pa, and the pressure of kiln tail is-10 to-120 Pa; observing the condition of the materials in the kiln during the period, so that the filling rate of the materials in the kiln is always more than or equal to 10%;
step three: the wind power of a kiln tail induced draft fan, the wind power of a wind supply Roots blower, the wind power of a kiln back blower, the wind power of a combustion-supporting blower and the opening degree of a kiln door are adjusted to form different wind supply structures, and a blank test is developed; testing the change rules of kiln temperature distribution and kiln pressure under various different air supply structures, analyzing and comparing experimental data, and summarizing the relation between the air supply structures and kiln temperature curves; the priority order of the air supply structure adjustment is as follows: kiln back fan > air supply Roots fan > combustion supporting fan > kiln tail induced draft fan > other;
step four: adjusting the air supply structure and the air supply quantity to ensure that the kiln temperature curve of the rotary kiln is consistent with the curve required by the production process and reaches a stable state for more than 1 hour;
step five: calculating the carbon consumption required by maintaining the current kiln temperature curve in an empty kiln state, namely the minimum carbon circulation base number, by weighing the carbon residue, simultaneously recording the air supply quantity corresponding to the current air supply structure, and according to the thermal engineering characteristics of the rotary kiln, calculating the iron oxide raw material quantity corresponding to the air supply quantity based on the carbon consumption and the air supply quantity by corresponding to 30% -40% of the thermal load of the rotary kiln according to the thermal engineering characteristics of the rotary kiln;
step six: the air supply structure and the air supply quantity are kept unchanged, iron oxide raw materials are added from the kiln tail, and the carbon quantity is increased, so that the kiln temperature curve is basically consistent with a blank test; according to the thermal engineering characteristics of the rotary kiln and the mechanism of metallurgical reduction reaction, because the air supply structure and the air quantity are kept unchanged, the rotary kiln can reach 60% -80% of heat load at the moment, so that the iron oxide raw material quantity of the rotary kiln at 100% of full load, namely the maximum productivity reference value, can be calculated according to the material quantity;
step seven: gradually increasing the iron oxide raw material amount according to the iron oxide raw material amount reference value calculated in the step six when the rotary kiln is fully loaded, stopping increasing the raw material amount when the raw material amount is increased until the rotary kiln is fully cooled, a high temperature zone is continuously moved or a certain parameter of the system reaches the upper limit, and recovering the last stable state, wherein the actual material amount is the actual maximum capacity of the rotary kiln, and recording the current process parameter value as the full-load stable state parameter.
Carbon and raw material selection: the carbon material must be coke or heat treated coal such as: recycling carbon residue, semi-coke, modified coal, etc. The carbon quantity fed into the kiln is regulated according to the carbon residue quantity of the kiln head, so that the carbon residue quantity is always more than or equal to 10%, and if the carbon residue quantity is less than 10% or continuously reduced, the carbon quantity added into the kiln tail is timely supplemented. The raw materials can be blocks, granules and powder containing iron oxide.
Use of a pellet coal injection system: when the raw materials enter the coal injection drop point area in the belt test, the metallization rate of the materials can be improved by injecting coal particles with the granularity of 5-30mm into the kiln from the kiln head, so that the temperature resistance of the materials is improved, and the risk of adjusting improper hot melting of the materials is reduced.
The priority order of the air supply structure adjustment is as follows: kiln lee fan > Roots fan > combustion-supporting fan > kiln tail induced draft fan > others.
The method for adjusting the kiln tail induced draft fan comprises the following steps: and the rotating speed of the induced draft fan is regulated in real time, the kiln head pressure is kept within the range of-20 to +20Pa, and the kiln tail pressure is kept within the range of-10 to-120 Pa. The induced draft fan at the kiln tail runs at the lowest rotation speed as far as possible on the premise of meeting the requirement of the pressure in the kiln.
Temperature measurement and temperature distribution curve drawing: the temperature of the kiln head and the kiln tail is measured by a thermocouple fixedly arranged on the rotary kiln, and the distribution condition of the kiln temperature curve is measured by a handheld temperature measuring device at intervals of 3-5 meters.
Examples:
in the following, a rotary kiln with a diameter of 3m and a length of 60m is taken as an example to treat blast furnace gas ash, so as to specifically describe how to adjust and calibrate the actual production load of a newly built (or modified) rotary kiln by adopting the above adjusting method.
Step 1: and starting related production equipment such as a rotary kiln, a kiln tail induced draft fan and the like, so that the rotary kiln is kept to operate at a rotating speed of 0.2r/min, and at the moment, using equipment such as a belt scale, a belt conveyor and the like to add coal into the rotary kiln from the kiln tail according to the material quantity of 2 t/h.
Step 2: igniting kiln head gas burner according to 300nm 3 And (3) continuously adjusting the rotating speed of the induced draft fan in real time in the whole process by using the gas quantity of/h from the kiln head to heat the rotary kiln, so that the kiln head maintains micro-positive pressure of 0-20 Pa, and the kiln tail ensures micro-negative pressure of-10 to-50 Pa, so that air and flue gas in the kiln can smoothly flow from the kiln head to the kiln tail. At this time, the other air supply devices are in a closed or minimum opening state.
Step 3: and when the kiln head has carbon residue for discharging, observing the filling rate, the inclination angle and the discharging amount of the materials in the kiln. By observing the inclination angle of the material in the kiln at 25 degrees, but the filling rate of the material in the kiln is less than 10 percent, the carbon inlet amount of the tail of the kiln is adjusted to be 3t/h, so that the filling rate of the material in the kiln is at least maintained to be more than 10 percent. The rotary kiln is continuously operated for more than 1 hour, and the kiln head temperature is kept above 900 ℃ stably. And calculating the residual carbon quantity by a weighing instrument of the finished product section, so that the residual carbon quantity of the kiln head discharged material is kept above 0.5 t/h.
Step 4: when the kiln tail temperature is higher than 500 ℃, opening gate valves of all kiln back fans 9, wherein the opening is the minimum 10%. Starting the air supply Roots blower 12, wherein the opening of a bleeding valve of the air supply Roots blower 12 is 30% -70%. Starting a granular coal injection system, and throwing 0.1-0.3t/h of granular coal into the kiln from the kiln head through a coal throwing Roots blower 13. When the temperature of the kiln tail is higher than 600 ℃, the gas of the gas burner 10 is closed, and 1000-3000 m of gas is reserved 3 Combustion air/h.
Step 5: according to the content of the patent, kiln temperature curves are adjusted by adjusting the opening of a gate valve of a kiln back fan, the opening of a diffusing valve of an air supply Roots blower, the coal throwing amount and the like, so that the kiln temperature curve of the rotary kiln completely meets the requirements of normal production processes. And the curve can be stably maintained for more than 1 hour, and if the curve can not be maintained, the step 4 is returned.
Step 6: recording the pure carbon mode of the rotary kiln after the operation is stableThe parameters of the air supply structure are as follows: the opening degrees of the kiln back fans 1-6 are respectively as follows: 10%, 30%, 50%, 70%, 50%, 30%, the opening of a coal throwing Roots blower bleeding valve is 60%, and combustion air is 1200nm 3 And/h. At this time, the residual carbon amount was weighed again to be 2.2t/h, whereby the kiln internal carbon consumption was found to be 0.8t/h, i.e., the carbon cycle base was: 0.8t.
Step 7: according to the theoretical value of the maximum design capacity of 7t/h of the rotary kiln, the method can be used for initially measuring and calculating that the treatment capacity of 2.1-2.8t/h can be supported under the carbon quantity. Taking the influence of other uncertain factors such as the actual air temperature into consideration, feeding the raw material of the blast furnace gas ash according to the raw material amount of 2t/h, and continuously increasing the raw material amount until the kiln temperature curve shows a descending trend, and stopping increasing the raw material amount. At this time, the measured maximum material under the air supply structure was recorded to be 3t/h.
Step 8: the air supply structure and the air supply quantity are kept unchanged, and coal with proper proportion is synchronously added according to the content of iron oxide in the raw materials. And (3) increasing the feeding amount until the kiln temperature curve cannot be maintained by increasing the blending coal, recording the actual feeding amount at the moment as 6t/h, and calculating the actual maximum productivity of the rotary kiln as 7.5-8.5 t/h.
Step 9: according to the target total amount of coal of which the gas ash raw material is externally matched with 4t/h at 8t/h, the kiln feeding amount is gradually increased. And the air quantity is synchronously improved according to the air supply structure, and various parameters of the rotary kiln are adjusted in a small range, so that the kiln temperature curve is always kept relatively stable. Finally, the actual maximum treatment capacity of the rotary kiln is 9t/h, and the corresponding main process parameters are as follows: kiln speed is 0.5r/min, and the opening degree of the kiln back fan is 1-6 respectively: 30%, 60%, 80%, 100%, 80%, 50%, 60% opening of a Roots blower blow-off valve, 0.5t/h of coal throwing amount and 3000nm of kiln head combustion air 3 And/h, finishing adjustment and calibration of the rotary kiln.
Claims (3)
1. The method for quickly adjusting the kiln of the metallurgical rotary kiln comprises the following steps of using a metallurgical rotary kiln system, wherein the metallurgical rotary kiln system comprises a rotary kiln (8), a raw material conveying system and a flue gas dust removal system are connected to the kiln tail of the rotary kiln (8), and a kiln tail induced draft fan (20) is arranged at the tail end of the flue gas dust removal system; the kiln back of the rotary kiln (8) is at least provided with a kiln backup fan (9), the kiln head of the rotary kiln (8) is connected with a granular coal injection system, an air supply Roots fan (12), a gas burner (10) and a finished product discharging system, and the gas burner (10) is also connected with a combustion-supporting fan (11); characterized in that the method comprises the steps of:
step one: starting the rotary kiln to enable the rotary kiln to normally operate at a rotating speed of 0.1-0.5 r/min, adding carbon materials into the kiln from the tail of the kiln by using a belt scale and conveying equipment at the moment, enabling the carbon materials to build a neat material layer and normally travel until the kiln head is discharged; the dip angle of the material layer is kept between 15 degrees and 45 degrees;
step two: igniting carbon materials of the whole kiln by using a gas burner, heating the rotary kiln to 600-1200 ℃, wherein the temperature of kiln tail smoke is 500-700 ℃, the temperature of kiln head cover is less than or equal to 900 ℃, the pressure of kiln head is-20 to +20Pa, and the pressure of kiln tail is-10 to-120 Pa; observing the condition of the materials in the kiln during the period, so that the filling rate of the materials in the kiln is always more than or equal to 10%;
step three: the wind power of a kiln tail induced draft fan (20), the wind power of an air supply Roots blower (12), the wind power of a kiln back blower (9), the wind power of a combustion-supporting blower (11) and the opening degree of a kiln door are adjusted to form different air supply structures, and a blank test is carried out; testing the change rules of kiln temperature distribution and kiln pressure under various different air supply structures, analyzing and comparing experimental data, and summarizing the relation between the air supply structures and kiln temperature curves;
step four: adjusting the air supply structure and the air supply quantity to ensure that the kiln temperature curve of the rotary kiln is consistent with the curve required by the production process and reaches a stable state for more than 1 hour;
step five: the carbon consumption required by maintaining the current kiln temperature curve in an empty kiln state, namely the minimum carbon circulation base number, is calculated by weighing the carbon residue, the air supply quantity corresponding to the current air supply structure is recorded, and according to the thermal engineering characteristics of the rotary kiln, the carbon consumption and the air supply quantity at the moment correspond to 30% -40% of the full load of the rotary kiln, so that the iron oxide raw material quantity corresponding to the air supply quantity can be calculated based on the carbon consumption and the air supply quantity;
step six: the air supply structure and the air supply quantity are kept unchanged, iron oxide raw materials are added from the kiln tail, and the carbon quantity is increased, so that the kiln temperature curve is basically consistent with a blank test; according to the thermal engineering characteristics of the rotary kiln and the mechanism of metallurgical reduction reaction, because the air supply structure and the air quantity are kept unchanged, the rotary kiln can reach 60% -80% of full load at the moment, so that the iron oxide raw material quantity of the rotary kiln at 100% of full load, namely the maximum productivity reference value, can be calculated according to the material quantity;
step seven: gradually increasing the iron oxide raw material amount according to the iron oxide raw material amount reference value calculated in the step six when the rotary kiln is fully loaded, stopping increasing the raw material amount when the raw material amount is increased until the rotary kiln is fully cooled, a high temperature zone is continuously moved or a certain parameter of the system reaches the upper limit, and recovering the last stable state, wherein the actual material amount is the actual maximum capacity of the rotary kiln, and recording the current process parameter value as the full-load stable state parameter.
2. A method for rapid kiln adjustment in a metallurgical rotary kiln as defined in claim 1, wherein: in the third step, the priority order of the air supply structure adjustment is as follows: kiln lee fan (9) >, air supply Roots fan (12) >, combustion-supporting fan (11) >, kiln tail induced fan (20) >, and others.
3. A method for rapid kiln adjustment in a metallurgical rotary kiln as defined in claim 1, wherein: and thirdly, measuring the temperature of the kiln head and the kiln tail of the rotary kiln by using a thermocouple fixedly arranged on the rotary kiln and measuring the distribution condition of the kiln temperature curve at intervals of 3-5 meters by using a handheld temperature measuring device to obtain a change curve of the temperature in the kiln along the length direction of the rotary kiln.
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| CN202311617812.6A CN117450779A (en) | 2023-11-30 | 2023-11-30 | Method for quickly adjusting kiln of metallurgical rotary kiln |
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