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Improvement of grate cooler and its effect analysis

  1. Conditions before transformation

  The 2500t/d clinker production line of shandong rizhao zhonglian cement plant is equipped with TC 1 1164 grate cooler, and the effective area of grate bed is 61.2m.

  5 rows of fixed grate beds, of which the effective area is 3.5m;

  The movable grate bed is divided into two sections with three air Chambers in each section. The structure of each air chamber and the distribution of air are shown in table 1.

  Before the transformation, the output of the grate cooler is about 2500 -- 2600t/d, and the cooling fan is fully open except for the fan with the opening degree of F4 ~ F6 at about 60%.

  At this point, the main problems are: two or three times the wind temperature is low, general secondary air temperature < 900 ℃, three times the wind temperature < 800 ℃, and waste heat power generation with wind temperature is close to 400 ℃;

  There is the phenomenon of "red river", and burn out grate plate, air chamber leakage red material and so on.

  Poor cooling effect, the grate cooler clinker temperature about 300 ℃, inclined zipper machine more red material, the serious influence the follow-up service life of the conveyor belt;

  The clinker quality was poor, and the clinker strength was less than 28MPa.

  Reason analysis and reform implementation

  2.1 cause analysis

  According to the analysis of the original configuration of the grate cooler and the study of the field application, the main reasons for the poor performance of the equipment are as follows.

  (1) the grate bed (especially the fixed grate bed and the first section of the grate bed) lack of air distribution, resulting in the high temperature clinker grate cooler in the high temperature end of the grate bed can not be quickly cooled.

  (2) the air supply mode is unreasonable, the cooling wind is easy to blow through the short circuit on the grate bed, the utilization rate is low, and with the deformation of the beam and the wear of the grate guard plate in production, the problem will gradually aggravate.

  For example, the two fans in the original fixed grate bed use left and right zones for air supply, which is inconsistent with the requirements of the material layer formed by hot materials falling on the fixed bed;

  For example, in the first section of movable grate bed, only four beams are provided with air by inflatable beams, and the grate bed has not taken any specific measures to mitigate the impact of material segregation.

  (3) the design of cooling air duct including grate plate is unreasonable. It can be seen from the scene that there are many pipe turns. The diameter of the pipe connected to the fixed beam is only 159mm.

  The above causes too much resistance along the way, resulting in too much fan head in the wasted effort, rather than used to really cool the clinker.

  In this way, the clinker at the high temperature end of the grate cooler can not be effectively and quickly cooling, resulting in two or three times of low air temperature, clinker poor quality;

  At the middle and low temperature end, the high temperature of the clinker entering the second moving grate bed leads to the high temperature of the waste heat generating wind, and the high temperature of the clinker leaving the grate cooler is abnormal.

  2.2 solutions

  According to the above problems and analysis, combined with the requirements of short construction period, low investment and large input-output ratio put forward by rizhao zhonglian cement plant, the following simple, practical, safe, reliable and practical technical renovation plan is formulated under the condition of keeping the appearance of grate cooler unchanged.

  (1) the fixed grate bed, the first section of the moving grate bed for a new upgrade.

  In the fixed bed, transverse grate plates without leakage material are used; in the first section of movable bed, transverse damping grate plates with low leakage material are used. For the same row of grate plates without leakage material, all grate beams and side protection plates should be replaced correspondingly, so as to ensure uniform gap of cooling air outlet and low resistance, and meet the air distribution needs of clinker cooling at the high temperature end.

  (2) in the first section of the moving grate bed, the side of part of the moving beam is separated by the bridge grate plate, that is, the two adjacent rows of moving grate plates ask a moving grate plate near the guard plate to be changed into a fixed bridge grate plate.

  In this way, the grate plates across the bridge can slow down the conveying speed of clinker, improve the distribution of clinker in the width direction of the grate bed, and realize the uniform cooling of the clinker on the grate bed by cooling wind.

  (3) improve the air supply mode and optimize the air supply pipeline.

  Among them, the air supply in the original left and right sections of the fixed grate bed was changed to the air supply in the middle part of the side to adapt to the rapid cooling needs of high-temperature materials stacked on the fixed bed;

  For the second and third air Chambers in the first section of the moving grate bed, the air supply from all the air Chambers of the fixed beam grate plates is the air supply from most of the air-filled beams, so as to eliminate the adverse effects of the changes in the overlapping joints of the grate plates caused by the deformation of the grate beam or the wear of the grate plates and the serious segregation on both sides of the grate bed.

  In addition, the air-filled beam supply duct adopts the method of reducing the resistance to reduce the useless power loss of the fan.

  (4) adjust the fan configuration and increase the hot end air supply.

  Specifically, a spare fan F1A of the original fixed grate bed was used in the new fixed bed, and a new fan F1C was used in the middle of the new fixed grate bed.

  The two F1A fans in the original fixed grate bed were moved to the air beam in the first air chamber, while the two F1B fans in the original first air chamber were used on the fine material side of the grate plate of the newly added fixed air beam in the second and third air Chambers, and a new fan F1D was used on the coarse material side of the grate plate of the newly added fixed air beam.

  Correspondingly, the air volume of the original fans F2 and F3 in the second and third air Chambers is reduced, while the others remain unchanged, as shown in table 2.

  3. Improvement effect

  The above reconstruction plan was implemented in the middle of February 2014, which lasted about 15 days and achieved good results.

  After the modification, the cooling effect of clinker at the high temperature end of grate cooler is greatly improved, so that the second and third air temperature is significantly increased, and the clinker quality and system output are improved, energy consumption is reduced, as well as the failure rate of equipment is reduced, and the maintenance cost is reduced.

  Transformation for months, after the production of the system output basically stable at around 2700 t/d, twice, three times the wind temperature reached to 1000 ℃ and ~ 900 oc, waste heat power generation wind temperature drop to ~ 300 ℃;

  The grate cooler clinker temperature drop to ~ 110 ℃, clinker strength of 3 d remain in 32 mpa;

  In addition, the grate bed on the "red river" phenomenon has been completely eliminated, there is no longer because of the grate cooler cooling effect is poor, causing grate cooler equipment fault or belt burn-out and other accidents.

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