Flue gas waste heat recovery method for rotary kiln

Abstract

The invention discloses a flue gas waste heat recovery method for a rotary kiln, wherein the method can be used for realizing the efficient and reliable waste heat resource recovery of the rotary kiln. The method is characterized in that the flue gas of a rotary kiln 1 is introduced into waste heat recovery heat exchangers 2 and 3, the heat exchangers absorb the heat in the flue gas up to the hilt, and the waste heat is utilized after being transformed into the enthalpy values of liquid, gas and steam; a flue gas steady flow system 4 is connected at the flue gas outlet of the heat exchanger 3 in series, the flue gas steady flow system 4 can perform automatic regulation according to the thermal regulation of the rotary kiln 1, so that the change brought by additionally arranging the waste heat recovery heat exchangers 2 and 3 can be overcome, and the different temperature field and pressure field parameters of the rotary kiln 1 under different working conditions can be maintained; and the rotary kiln 1 is also provided with a radiation heating surface which can absorb high-temperature radiant heat so as to reduce the heat dissipation of the rotary kiln 1 and recover the waste heat in all directions, thereby most comprehensively recovering the waste heat up to the hilt, and simultaneously ensuring that the rotary kiln operates stably, parameters have no need to be changed and can not be changed, and the quality of produced products is not influenced at all.

Description

technical field [0001] The invention relates to a method for recovering waste heat from flue gas of a pre-roasting rotary kiln Background technique [0002] The sintering process of ferrite pre-sintered material in the rotary kiln is the key to ensure the quality of permanent magnet ferrite products. When the permanent magnet ferrite magnetic powder sintering technology is carried out in the sintering system, the precise requirements of the process for the sintering process must be strictly implemented. High temperature direct discharge method. Because the flue gas temperature of some rotary kiln pre-firing systems is too high (usually as high as 900°C), a blower has to be used to introduce normal temperature air for mixing to reduce the flue gas temperature, so as to reduce the investment in the exhaust system and prolong the life of the exhaust system. The main schemes of the flue gas waste heat recovery project of the rare rotary kiln pre-firing system include: figure ...

AI Technical Summary

Problems solved by technology

This design scheme has the following defects: ① Increase the smoke exhaust resistance of the rotary kiln pre-burning system, resulting in difficulty in smoke exhaust, changes in the pressure field and temperature field in the rotary kiln, affecting the pre-burning effect, and the quality of permanent magnet ferrite powder will be affected. Influence; ②, "heat grabbing phenomenon" occurs, that is, after installing a waste heat recovery heat exchanger on the exhaust channel of the rotary kiln pre-combustion system, the temperature in the kiln will drop under the same input heat of the rotary kiln. to the temperature required by the process; ③, unable to maximize the recovery and utilization of waste heat from flue gas

On the one hand, the flue gas of the pre-burning rotary kiln often contains corrosive components, such as sulfur, which are prone to low-temperature corrosion, so the waste heat recovery heat exchanger must have high temperature corrosion resistance; on the other hand, the temperature of the flue gas discharged from the rotary pre-burning rotary kiln is relatively high , usually up to 900°C, to require the waste heat recovery heat exchanger to be resistant to high temperatures, and there is still no heat exchanger that can perform these two functions well at the same time; ④, it is impossible to fully utilize the waste heat resources of the rotary kiln

The rotary kiln emits a large amount of high-temperature radiant heat to the surroundings. Although the kiln body has done limited heat insulation, there is no recycling.

Images