Device and method for recovering afterheat during red hot pellet cooling of rotary hearth furnace

Abstract

The invention relates to a device and a method for recovering afterheat during red hot pellet cooling of a rotary hearth furnace. A charging bucket is arranged on the top of a vertical contraflow cooler; an upper pipeline of the vertical contraflow cooler is connected with a first-stage dust pre-remover; the pipeline of the first-stage dust pre-remover is connected with the upper part of a boiler; the bottom of the boiler is connected with a second-stage bag-type dust remover; and the second-stage bag-type dust remover is connected with the lower part of the vertical contraflow cooler througha circulating fan. The method for recovering the afterheat comprises the following steps of: performing contact heat exchange between low-temperature nitrogen and red hot pellet until the temperatureof the low-temperature nitrogen is 800 DEG C; removing dusts from high-temperature nitrogen; cooling the high-temperature nitrogen until the temperature is 200 DEG C and producing steam; removing dusts from the cooled nitrogen; and recycling the low-temperature nitrogen. By adoption of the invention, closed cycle of the nitrogen can be realized so that recycling of energy mediums can be realized;meanwhile, separation between powder and the pellet is realized by controlling a flow speed of the pipeline nitrogen; moreover, due to the contact contraflow heat exchange, quick cooling is realized and the afterheat utilization efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of waste heat recovery, in particular to a waste heat recovery device and method for cooling red-hot pellets in a rotary hearth furnace. Background technique [0002] As a new type of pelletizing processing and manufacturing equipment, the rotary hearth furnace has been rapidly promoted around the world. The promotion of rotary hearth furnace technology has effectively improved the technical means of preparing pellets, thereby alleviating the bottleneck problem of insufficient high-quality pellet resources. Although the rotary hearth furnace has explored and applied the waste heat recovery technology of the high-temperature flue gas system, and the effect is remarkable, but the waste heat energy in the red-hot pellet cooling process has not been efficiently recovered and utilized. [0003] The temperature of the pellets discharged from the rotary hearth furnace is generally controlled at 1100°C. In order to...

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Problems solved by technology

[0005] Due to the non-contact cooling of the horizontal rotary drum cooling structure, the cooling time is relatively long, and the operating cost of the system equipment is high. At the same time, the waste heat generated in the cooling process is not recovered in the whole process, and the steam generated by the drum wall is directly discharged. Cause waste of water resources and affect the environment

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