A lime powder composite roasting system and method

Abstract

The invention discloses a lime powder composite roasting system and a lime powder composite roasting method. The system mainly comprises a raw material delivery and combustion heating unit, a multi-stage cyclone separation unit, a residual heat recovery and dedusting unit, and a power generation unit, which are sequentially connected through pipes and which matches each other. With the lime powder composite roasting system and the method provided by the invention, defects such as low temperature control precision, high device cost, large energy consumption, low raw material utilization rate, poor product quality, and the like of prior arts can be overcome. The system and the method has the advantages of high temperature control precision, low device cost, low energy consumption, high raw material utilization rate, and good product quality.

Description

technical field [0001] The invention relates to the technical field of limestone firing technology, in particular to a lime powder composite firing system and method. Background technique [0002] At present, the lime firing process at home and abroad generally adopts shaft kiln or rotary kiln, and the particle size of the raw material is also block limestone larger than several centimeters. However, the existing limestone firing process has the following characteristics: [0003] ⑴Because larger stones are not easy to burn through, in order to avoid "under-burning" inside the stone, the temperature in the calcination zone (firing area) in the kiln will reach 1200-1300°C, which causes "over-burning" outside the stone. burn"; [0004] (2) The temperature in the firing area of ​​the rotary kiln is mostly controlled by the experience of the workers, and it is difficult to achieve consistent high temperature field in the firing area of ​​the vertical kiln. Therefore, the curre...

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Problems solved by technology

[0003] ⑴Because larger stones are not easy to burn through, in order to avoid "under-burning" inside the stone, the temperature in the calcination zone (firing area) in the kiln will reach 1200-1300°C, which causes "over-burning" outside the stone. burn";

[0004] (2) The temperature in the firing area of ​​the rotary kiln is mostly controlled by the experience of the workers, and it is difficult to achieve consistent high temperature field in the firing area of ​​the vertical kiln. Therefore, the current production process is difficult to solve the contradiction between under-burning and over-burning. The proportion of underburning and overburning is generally higher than 10%, and some kilns even exceed 20%, which seriously affects the quality of lime;

[0005] (3) In order to burn through the large-grained stones, it is necessary to prolong the residence time of the stones in the high-temperature zone, so the kiln body is very large and complicated, the equipment cost is also very expensive, the heat loss is large, and the energy consumption is high;

[0006] ⑷The stones that are not suitable for entering the kiln because the particle size is less than 20mm are thrown away, and the utilization rate of the raw ore is less than 75%;

And because the equipment is complicated and tall, the temperature of the exhaust gas and the finished product is also high, resulting in high energy consumption, so the product quality and economic benefits are not high;

[0008] ⑹ There are also improved rotary kilns that can calcinate millimeter-scale small particles, but for those finer ore powders, they are often blown away by the airflow before being calcined at high temperature, and the quality is difficult to control

[0009] In the process of realizing the present invention, the inventors found that there are at least defects in the prior art such as low temperature control accuracy, high equipment cost, high energy consumption, low raw material utilization rate and poor product quality.

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