Microwave kiln for assisting in cement clinker calcination and microwave calcination method thereof

Abstract

The invention discloses a microwave kiln for assisting in cement clinker calcination. The microwave kiln for assisting in cement clinker calcination comprises a kiln body and further comprises a rotary kiln cover, a driving mechanism, a fixed kiln cover, a distributing device, a microwave generator and a waveguide tube, wherein a draught fan is installed on the bottom of the kiln body, and the rotary kiln cover is installed on the kiln mouth of the kiln body. According to the microwave kiln for assisting in cement clinker calcination, microwave field radiation is even; the rotary kiln cover is arranged, the waveguide tube and the microwave generator are installed on the rotary kiln cover and rotate along with the rotary kiln cover, and a microwave field which is large in coverage area and even in microwave radiation is formed gradually in the kiln body by microwaves emitted by the microwave generator during rotation; in addition, an annular power supply slide wire and the driving mechanism are arranged, the rotating speed of the rotary kiln cover can be adjusted through the driving mechanism, and thus the microwave field can be adjusted.

Description

technical field [0001] The invention relates to a cement clinker calcining equipment and method, in particular to a microwave kiln for assisting in calcining cement clinker and a microwave calcining method thereof. Background technique [0002] Since the invention of cement, the calcination of its clinker has always used coal or a small amount of natural gas as the heat source. The way to heat the material is mainly conduction and convection, supplemented by radiation. The heating of the material has a heat transfer process from the outside to the inside, forming a large The temperature gradient leads to inconsistent chemical reaction speed, which affects the improvement of clinker quality; in addition, the temperature rise rate of the material through the combustion of the medium is slow, generally 10-20°C / min, the clinker calcination time is long, and the thermal efficiency is low; at the same time, due to the material The particle size and the side wall effect of the kiln...

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Problems solved by technology

[0002] Since the invention of cement, the calcination of its clinker has always used coal or a small amount of natural gas as the heat source. The way to heat the material is mainly conduction and convection, supplemented by radiation. The heating of the material has a heat transfer process from the outside to the inside, forming a large The temperature gradient leads to inconsistent chemical reaction speed, which affects the improvement of clinker quality; in addition, the temperature rise rate of the material through the combustion of the medium is slow, generally 10-20°C / min, the clinker calcination time is long, and the thermal efficiency is low; at the same time, due to the material The particle size and the side wall effect of the kiln equipment itself cause uneven cross-section ventilation, which also affects the improvement of clinker quality

[0003] In addition, the combustion process of coal is also a process from drying and preheating, volatile matter escape combustion, to fixed carbon combustion with the increase of temperature. The excess air coefficient is high, and the combustion speed of coal is fast, but the heat loss due to ventilation is large; Low air excess coefficient, poor ventilation, prominent chemical incomplete combustion, waste of heat energy, and failure to meet the temperature requirements required for calcination at each stage

[0004] In the actual production process, due to the demand for heat from clinker formation, the coal content in raw materials is generally about 10%, and the physical conditions of high air excess coefficient are not easy to meet, and the amount of oxygen inside the ball is small, which leads to chemical incomplete combustion. It must exist, and the heating rate of the material can only reach 10-20m / min in general, which restricts the chemical reaction speed and reaction quality of clinker formation, thereby limiting the quality of clinker

[0005] Therefore, people have added microwave generators on some microwave equipment to assist in calcining cement. For example, the patent application number 00102065X adds a microwave emission tube to the high-temperature zone of the rotary kiln, and radiates the high-temperature zone through the microwave field to improve the calcined cement. quality; but many devices with microwave transmitters are the same as the above-mentioned patents, the radiation of the microwave field to the kiln cannot be uniformly distributed, and the irradiation area of ​​the microwave field to the kiln is fixed, which cannot really increase the heat of calcination and quality, it will still cause the occurrence of overburning and raw burning of cement clinker, and the microwave field only irradiates the high temperature zone of the kiln, but does not irradiate the preheating decomposition zone and the solid phase reaction zone. The quality of cement clinker cannot be guaranteed to be stable

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