Temperature control method for reduction rotary kiln

Abstract

The invention provides a temperature control method for a reduction rotary kiln. The temperature control method includes the following steps of: additionally arranging an ultrasonic temperature and distance measurement analyzer on a kiln head cover of the rotary kiln; monitoring the temperature along a kiln length direction line on line in real time; simultaneously installing a series of secondaryair nozzles on a kiln body in the kiln length direction; and changing the air volume of the secondary air nozzle at the corresponding point according to the difference between the temperature of a measured point and a target temperature to ensure that the uniformity of a temperature field in the kiln and along the length direction of the kiln is guaranteed, the local temperature is prevented frombeing too high or too low, ring formation in the rotary kiln is avoided, a longer high-temperature zone is provided for reduction materials, and the product quality index is remarkably improved; besides, volatile components, CO and the like volatilized from material layers are fully combusted with secondary air, so that the reduction materials in the rotary kiln are provided with a temperature, the content of volatile components and CO entering a re-combustion chamber is greatly reduced as well, the fuel utilization efficiency is high, and high-temperature ring formation and water explosion of the re-combustion chamber are avoided.

Description

technical field [0001] The invention relates to a temperature control method for a rotary kiln, in particular to a temperature control method for a rotary kiln used for oxide reduction, and belongs to the technical field of the rotary kiln. Background technique [0002] The environmental protection department has long 2 and NOx emission charges, as the pressure on carbon emission reduction intensifies, China's carbon emission trading system is about to operate, CO 2 Emissions will also be gradually included in the scope of payment. The traditional long process will bring a higher cost burden to steel enterprises than the short process; the world's steel development trend is gradually transitioning from the long process of "blast furnace-converter" to the short process of "direct reduction (scrap steel) - electric furnace". It will be increased from 66.8% to 70%, and many blast furnaces will be closed or temporarily idle; direct reduction + electric furnace short process is...

AI Technical Summary

Problems solved by technology

[0012] In view of the existing technology, the temperature in the rotary kiln along the kiln length is uneven, easy to form rings, and the reduction efficiency is low; the high temperature section is short, volatile matter and CO escape into the reburning chamber, and the temperature is difficult to control, the output is small, and the energy consumption is low. High; the temperature cannot be accurately monitored in real time online, causing technical problems such as incoordination between the air supply system, the fuel system, and the temperature, and easy ring formation; the present invention proposes a method for controlling the temperature of the reduction rotary kiln. An ultrasonic temperature measurement and distance measuring analyzer is added to monitor the temperature along the kiln length line in real time. At the same time, a series of secondary air nozzles are installed on the kiln body along the kiln length direction. According to the difference between the measured point temperature and the target temperature, change The air volume of the secondary air nozzle at the corresponding point ensures the uniform temperature field in the kiln along the kiln length direction, prevents local temperature from being too high or too low, avoids the occurrence of ring formation in the rotary kiln, and provides a longer high temperature zone for reducing materials , the product quality index has been significantly improved; in addition, the volatile matter, CO, etc. volatilized in the material layer are fully combusted with the secondary air, which not only provides temperature for the reduced material in the rotary kiln, but also greatly reduces the volatilization into the reburning chamber and CO content, high fuel utilization efficiency, avoiding high-temperature ring formation and "water explosion" in the reburning chamber

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