Comprehensive controlling method and comprehensive controlling system for temperature field and air pressure field of grate bed of grate

Abstract

The invention discloses a comprehensive controlling method and a comprehensive controlling system for a temperature field and an air pressure field of a grate bed of a grate, and relates to the field of measurement and control technology of metallurgical industry. The technical proposal adopted by the invention comprises the following steps: designing a hot airflow flowing route of the grate; determining the air pressure gradient relation among sections of the grate bed of the grate; determining the temperature gradient relation among the sections of the grate bed of the grate; establishing a comprehensive control strategy based on an air pressure gradient field and a temperature gradient field of each section of the grate bed of the grate; and establishing the comprehensive controlling system for the temperature field and the air pressure field of the grate bed of the grate. Through the comprehensive control of the temperature field and the air pressure field of the grate bed of the grate, the real-time control of the temperature gradient field of the grate bed of the grate is easier and steadier to improve the utilization efficiency of hot wind energy, improve the compressive strength of pellets, ensure the quality of the pellets and prolong the service life of the grate.

Description

technical field [0001] The invention relates to a method for comprehensively controlling the grate bed temperature field and air pressure field of a grate machine and its control system, which belongs to the technical field of metallurgical industry measurement and control, and is mainly used to realize the real-time stability of the grate bed temperature field and air pressure field of a pellet chain grate machine control. Background technique [0002] Grate machine is one of the key equipment for producing pelletized metallurgical materials, mainly used for drying and preheating green pellets. It spreads the green balls on the grate plate of the grate bed of the grate machine running at a slow speed, and uses the waste heat of the annular cooler and the hot air discharged from the rotary kiln to carry out blast drying, draft drying and preheating oxidation of the green balls, and achieves After sufficient compressive strength, it is directly sent to the rotary kiln for ro...

AI Technical Summary

Problems solved by technology

[0003] When the temperature field of the grate bed of the grate machine is not effectively controlled, there are problems: the temperature of the grate bed is too high, and the service life of the grate machine will be greatly reduced; the temperature rises too fast during the drying process, and the green balls are easy to explode; The process temperature does not meet the requirements, and the green pellets do not have sufficient compressive strength, which affects the quality of the pellets

This control method only considers the control of the temperature field, and does not consider the control of the pressure field. The existing problems are:

[0005] (1) When the air pressure above the grate bed in the blast drying section of the chain grate machine exceeds the air pressure above the grate bed in the draft drying section, a large amount of low-temperature hot air in the blast drying section will be directly sucked into the draft drying section through the gap between the partition walls, reducing The hot air temperature of the draft drying section is increased, the water vapor content is increased, and the drying effect of the draft drying section is reduced. A large amount of hot air above the grate bed in the drying section flows to the blast drying section, which makes the drying effect of the bottom pellets in the draft drying section worse and affects the quality of green pellets

[0006] (2) When the air pressure above the grate bed in the exhaust drying section of the chain grate machine exceeds the air pressure above the grate bed in the preheating section, the hot air containing evaporated water vapor in this section will flow to the preheating section, which will affect the preheating temperature of the green pellets in the preheating section and reduce the utilization of heat sources Conversely, when the air pressure above the grate bed in the draft drying section is much lower than the air pressure above the grate bed in the preheating section, a large amount of hot air above the grate bed in the preheating section will also flow to the draft drying section, thus making the preheating effect of the bottom pellets in the preheating section less Poor, affecting the quality of green balls

[0007] (3) The heat required in the preheating section mainly comes from the rotary kiln. If the negative pressure in the preheating section is too small, the hot air from the rotary kiln will not enter the preheating section smoothly, which will destroy the heat balance. Long-term work will cause the sealing cover of the rotary kiln to The cylinder is burned out by high temperature; on the contrary, if the negative pressure in the preheating section is too large, a large amount of high-temperature gas of 1000 °C coming out of the rotary kiln will make the preheating section too high, which will make the grate bed temperature too high, greatly reducing the service life of the grate bed

This patent only considers temperature control and air pressure control separately, does not consider the relationship between temperature and air pressure, and comprehensively controls temperature and air pressure

Images