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Introduction to the optimization and transformation of SJK g

  An overview,

  Grate cooler is one of the core equipment of the firing system, it and the preheater, calciner, rotary kiln, burner and other components of the firing system, its performance, the performance of the firing system plays a key role in the operation rate and performance.

  Some people compared grate cooler to the "burning system of the engine," it not only plays the role of cooling clinker, conveying clinker, but also for the kiln combustion to provide two or three times of wind, coal mill drying, waste heat power generation to provide heat.

  Only the grate cooler with excellent performance can realize higher clinker cooling capacity and heat recovery efficiency and provide sufficient higher air temperature for the kiln.

  Raising the temperature of two or three times and optimizing the furnace air supply are the most direct means of sintering optimization, which is the key to achieve the improvement of quality, production, consumption and emission reduction. There are also cases that "the improvement of grate cooler and the optimization of preheater are the same".

  Two, the grate cooler design defects

  Grate cooler used in industry for the third generation, fourth generation of grate cooler, due to design flaws, system above, plus the air distribution is unreasonable, not scientific, grate plate form the two or three times the wind, low temperature waste heat power generation, honghe, discharge temperature, the high problems emerged at the same time, has highlighted the grate cooler in firing system bottleneck position, of clinker production process in the "good quality and high yield authors, increase efficiency" goal.

  The technological design defects and influence of grate cooler are listed for discussion

  1. The fixed bed

  1.1 fixed design defects

  1.1.1 part fixed bed slope Angle, the length of the grate cooler design rationality, opinions vary on this, the differences, caused by a lack of lack of related discipline knowledge, design basis, add in fixed bed for long, part of the design of more than 2.4 m, even have more than 3 m, slope Angle is too big, there are more than 14 °, even achieve 17 ° above;

  1.1.2 the fixed bed of some grate coolers and the step height of one room exceed 300mm, and some models are much higher than this;

  1.1.3 most grate cooler fixed bed partition air supply is not scientific or do not partition;

  1.1.4 fixed bed design defect is the problem thoroughly solved by domestic and foreign grate cooling mechanism manufacturers and technical innovation enterprises.

  1.2 results of fixed bed design defects

  1.2.1 frequent snowman accidents;

  1.2.2 secondary and tertiary air temperature is low, honghe is serious, discharge temperature is high, waste heat power generation is not ideal, grate cooler heat recovery efficiency is not ideal.

  2. With the wind

  2.1 defects of air distribution design

  2.1.1 air distribution design basis in the industry has not clearly given the specific standards, clinker cooling design with the wind from 1.6 to 2.6m /kg, or even large air volume is small twice the relationship between;

  2.1.2 the issue of zero pressure point (high temperature and middle temperature) has been endlessly debated. Discussions like "the blind men feel the elephant" are common, and "windscreen wall and zero pressure wall" of some models have become the standard configuration;

  2.1.3 fuzzy concept of functional zoning;

  2.1.4 unreasonable fan selection, functional zoning and low fan efficiency.

  2.2 results of defects in wind distribution and functional zoning design

  2.2.1 secondary and tertiary air temperature is low, honghe is serious, discharge temperature is high, waste heat power generation is not ideal, grate cooler heat recovery efficiency is not ideal;

  2.2.2 the internal and external air leakage and channeling of grate cooler are serious, resulting in misleading operation of feedback parameters and affecting the realization of the correct design concept of air distribution.

  3. Grate plate

  3.1 defects in grate plate design

  3.1.1 the grate design is not reasonable, and the high resistance grate maintains the wind speed 60m/s;

  3.1.2 the debate between high resistance grate and low resistance grate is continuous and has not been settled yet;

  3.2 results caused by design defects of grate plates

  3.2.1 the grate is blocked or blocked, and the leakage is serious or cannot be eliminated;

  Grate ablation is serious;

  3.2.2 high resistance grate affects the control of material layer thickness. Without higher material layer thickness, it is difficult to achieve greater cooling capacity and heat recovery efficiency.

  4. The red river:

  4.1 the application of the baffles once made outstanding contributions to the treatment of "red river". However, "heroes are also dying". With the increase of the overproduction range, the role of the baffles technology is difficult to play, or even has a negative effect;

  4.2 fixed bed design defects, air distribution design defects and grate plate design defects are the root of repeated treatment of honghe.

  Three, SJK grate cooler optimization and transformation of the technical concept

  1. SJK engineers and technicians combine cement technology, combustion science, thermal dynamics, fluid mechanics and mechanics, and put forward the design concept of "coal-based material, drag reduction and efficiency improvement, fixed-point zoning, and scientific air distribution".

  2. Coal-based: grate cooler, as the key equipment of the production line, provides secondary air for clinker cooling and kiln furnace;

  According to the output and heat consumption of clinker, determine the total volume of second and third air.

  3. Resistance reduction and improvement: SJK low resistance grate plate is adopted to reduce the resistance of grate bed and reasonably control the thickness of high material layer (suggested reasonable value: 0.8m -- 1.2m) to improve the quenching effect of clinker, increase the second and third air temperature and improve the heat recovery efficiency.

  4. Fixed-point zoning: the blanking point of the grate cooler and the partition of the fixed grate plate of the fixed bed are accurately determined.

  SJK point of view: the location where the clinker falls on the grate is an area.

  The following parameters are required to calculate the location of the unloading point: the normal granulation ratio of clinker, the normal kiln speed, the location of the hot kiln opening, the vertical distance from the kiln to the grate cooler, and the distance of the grate cooler from the kiln axis. The range can be determined by the comprehensive calculation of thermodynamics and physics.

  5. Scientific air distribution: according to the total amount of the second and third times, the zero pressure point of grate cooler is calculated scientifically (or known as the zero pressure surface, some of the grate cooler has a baffle wall or zero pressure wall), and the fan is rationally configured to ensure stable production and low consumption.

  Zero pressure point from SJK point of view: before the zero pressure point, the air distribution must meet the requirement of furnace air, which slightly moves back and forth depending on the output, coal consumption and operation method at the station.

  SJK cooling philosophy: the heat exchange efficiency of clinker is the highest in the high temperature section (fixed bed), and the heat exchange efficiency decreases with the decrease of clinker temperature (the lower the temperature difference, the lower the heat exchange efficiency);

  Clinker in the high temperature section did not get rapid cooling, to the middle and low temperature section by strengthening the cooling to normal temperature is impossible.

  Iv. Brief introduction to the optimization and transformation method of SJK grate cooler (excluding the transmission part)

  1. The fixed bed

  1.1 geometric parameters of fixed bed

  1.1.1 fixed bed slope Angle, the appropriate Angle of 11-13 °, have pushed the snowman device can put Angle in 10 °, is not reasonable to make corrections;

  1.1.2 the length of fixed bed should be 1.7-2.1m, and the unreasonable length should be corrected;

  1.1.3 the step height between the fixed bed and one room should be less than 150mm, which is unreasonable and needs to be adjusted;

  1.2 fixed bed partition air supply

  1.2.1 based on normal clinker granulation ratio, normal kiln speed, hot kiln opening position, vertical distance between kiln and grate cooler, and the distance between grate cooler and kiln axis, the drop point of grate cooler can be accurately determined by comprehensive thermodynamic and physical calculation, and then the fixed bed grate plate partition can be determined.

  1.2.2 three-generation grate cooler fixed bed partition plan I (original air-filled beam direct partition) : the fixed grate plate of the fixed bed is directly divided into three to five zones (patent no. : 201810334554.3), and a fan is added at the same time;

  If the original fixed bed and one room share one balance fan, one room and the fixed bed need to be separated, need to add a fan;

  1.2.3 division plan 2 for fixed bed of three-generation grate cooler (SJK fixed bed division) : remove the original fixed bed and replace it with SJK fixed bed, and then scientifically divide the fixed bed air box into three to five zones according to the original fans (patent no. : 201820531642.8), and add one to three fans;

  2. Division plan for fixed bed of fourth-generation grate cooler: the original fixed bed was modified into SJK fixed bed for inflatable box, and then the fixed bed for inflatable box was divided into three to five zones (patent no. : 201820531642.8), adding one to three fans;

  3. Grate plate

  3.1 according to the original grate structure, combined with the needs of air distribution, the grate is designed specifically, and the installation size of the grate is generally not changed;

  3.2 replace the fixed bed and one-chamber grate plate with SJK low-resistance grate plate (patent no. 201820170303.7);

  3.3 the two Chambers and the later grate plates are all designed in accordance with the specific design. They should be replaced according to the design needs or after wear and tear.

  4. Treatment of honghe river

  4.1 the fine material side adopts SJK lateral grate plate technology (patent no. : 201821026632.5) to eliminate or alleviate the phenomenon of honghe river, and an additional fan is needed;

  4.2 if the over-production range is too high, SJK lateral grate technology can be adopted on both sides.

  5. Air distribution method

  5.1 calibrate the original cooling fan's air pressure and air volume;

  5.2 according to the heat consumption of clinker, the current situation of coal burning and the output per hour, the total amount of secondary and tertiary air into the furnace is calculated scientifically, and the theoretical zero pressure point is set;

  5.3 if there is zero pressure wall or wind shield, it shall be removed;

  5.4 give consideration to residual heat power generation, adjust the overall wind distribution of grate cooler, and do not make any adjustment if it is reasonable. If it is not reasonable, adjust the wind distribution again. If necessary, repair the impeller or replace the fan.

  6. Fan adjustment

  6.1 two transformation schemes can be provided for SJK of three-generation grate cooler, and the total number of fans will increase by 1-3;

  6.2 for the SJK of the fourth-generation grate cooler, a set of transformation scheme can be provided, and the total number of fans can be increased by 1-3.

  V. summary of patent technology related to SJK grate cooler optimization

  Patent name: a grate cooler of the gas box fixed grate bed

  Patent no. : 201810334554.3

  Use position: fixed bed

  Remarks: designed specifically to ensure heat recovery efficiency

  Patent name: cement clinker grate cooler partition combination of air box fixed grate bed

  Specialist no. : 201820531642.8

  Use position: fixed bed

  Remarks: designed specifically to ensure heat recovery efficiency

  Patent name: a grate cooling machine of low resistance grate plate

  Specialist no. : 201820170303.7

  Use position: all grate plates

  Note: targeted design can increase the thickness of material layer

  Patent name: a grate cooler side inflatable low resistance leakage protection plate

  Patent no. : 201821026632.5

  Application position: fine material side

  Note: solve the honghe problem

  Five, the review

  Through the use of SJK grate cooler optimization reconstruction technique can make the secondary air temperature stability in 1150 + 50 ℃, discharge temperature environment temperature + 65 ℃ or less or ideal values (particle size 25 mm or less and 95% or higher), at the same time can reduce the grate cooler reducing atmosphere, improve the quality of clinker, raising clinker grinding ease;

  And can greatly reduce the process accident and equipment failure rate, greatly improve the equipment operation rate, to achieve energy saving, consumption reduction, improve the production of the technical reform goals.

  SJK believes that the advanced grate cooler should have the operating indicators

  Material: 1, the discharge temperature discharging temperature environment temperature + 65 ℃ 100 ℃ or less;

  2, secondary air temperature: secondary air temperature is 1150 ℃, or 1180 ℃ or less best temperature 1220 ℃ or less;

  3, three times the wind temperature, three times the wind temperature 900 ℃, or 950 ℃ or less best temperature 1000 ℃ or less;

  4, process accidents: no "red river", "snowman" and other process accidents;

  5, cooling capacity: ㎡ cooling capacity of 45-48 t / ㎡, d, up to 50 t / ㎡, d;

  6, cooling power consumption: tons of clinker cooling power consumption 5.5kwh;

  7 waste heat power generation: the waste heat power generation load rate is above 95%;

  8. Operation rate: the mechanical failure rate is low, and the relative operation rate is above 99%.

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