Problems that should be avoided in the production of environmentally friendly lime kilns

1) The limestone size is too large : the calcination speed of limestone depends on the temperature at which the particle size of lime contacts with the surface of limestone. At a certain temperature, the rate of calcination of limestone depends on the size of the limestone.The larger the particle size, the slower the calcination speed.Since the thermal conductivity of lime is smaller than that of limestone, the more difficult it is for the heat to enter the stone as the thickness of the lime layer increases, and the calcination speed slows down.So large blocks of limestone tend to have sandwich, which is the main reason for lime burning.The particle size of the ordinary environment-friendly lime kiln should be controlled at 40-80mm, and the size of the kiln can be relaxed to 50-150mm.

2) Small proportion of fuel or low fuel calorific value: the ratio of environment-friendly lime kiln fuel is related to the technical performance of the lime kiln. At present, the coal used for burning a ton of lime in some new environment-friendly lime kilns has dropped below *125 kg. Generally, the calorific value of environment-friendly lime kiln coal is more than 5500 kcal.The particle size of the fuel should be controlled, and water should be added when the coal is used.

3)Unreasonable air supply: environmental protection kiln in reaction to generate lime stone rely on fuel burning high temperature firing, and fuel burning need oxygen (air) combustion, any fuel burning should have three necessary conditions for fuel, oxygen, ignition source landscapes themselves, and it is the wind wind and fire, the fire in addition to the coal and limestone in a certain proportion to join, reasonable for wind also appears especially important, environmental protection kiln section on local air volume have greatly small, windy place the coal burning full, high ambient temperature, wind small area coal combustion is not sufficient, inadequate response, limestone ShengShao phenomenon.In order to make the air supply reasonable, by adjusting the air supply height and computer simulation hood, the air pressure can enter into the section of the environment-friendly lime kiln stably and evenly, and the fuel can be burnt evenly.Production practice experience shows that vertical lime kiln environmental protection low productivity and production by the lime active degree is caused by the unreasonable air flow distribution in the furnace, and the flow distribution is not reasonable to reflect the defects in the structure of computer simulation cowl, my company integrating technology, through the computer simulation software to simulate the change of the flow field around hood, analysis the simulation results found on top of the hood airflow “dead zones”.By setting a special air duct on the top of the hood, the central airflow is opened up and the “dead zone” of airflow is eliminated, so as to avoid the burning phenomenon caused by the central suction. After the hood structure transformation, the airflow distribution in the lime kiln is more even, and the lime activity produced by the hood is increased by more than 15% compared with the unreformed lime activity.

4) Over burning: the quality of quicklime, on the one hand to check the content of calcium oxide, magnesium oxide, on the other hand to see the rate of overburning of quicklime, raw burning is part of the limestone is not completely decomposed, overburning is calcination of limestone, so that quicklime dense, also known as fire lime or dead burned lime.This part of quicklime activity is low, difficult to decompose, ordinary limestone, the normal combustion temperature is l000-1200℃, usually over burnt lime is burning temperature too high, long time, surface cracks or glass shell, volume shrinkage is obvious, the color burned into black, block capacity increased.Reasons for overburning: first consider whether the ratio of fuel is too large, should be adjusted to reasonable ingredients, coal blending quantity should fully consider the quality of coal, in addition to adjust the appropriate air supply.Rotation is the case to solve control coal ratio and fuel in environmental protection kiln are arranged in the main method of uniform, multipoint rotary feeder can realize single point, multi-point, forward and reverse charging operation, which can control the case material flow, feed rate, fuel cloth evenly, make fuel uniform and fully mixed with the raw material, the combustion.


Post time: May-25-2020

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