A continuous cooling preheating and waste heat recovery system and its flexible control method

Abstract

The invention discloses a continuous annealing and preheating and waste heat recovery system and a flexible control method thereof. The continuous annealing and preheating and waste heat recovery system comprises a preheating section and a waste heat recovery section, wherein the waste heat recovery section is connected with the preheating section, the preheating section comprises a gas collectingchamber, a preheating box body, heat exchangers, a plurality of pairs of air injection bellows, a plurality of circulating fans and a smoke discharge fan, the gas collecting chamber communicates withthe upper end of the preheating box body, the plurality of pairs of air injection bellows are all arranged in the preheating box body, the heat exchangers are respectively arranged in each air injection bellows, the plurality of circulating fans are all arranged in the preheating box body, each circulating fan communicates with one pair of air injection bellows, the lower end of the preheating box body communicates with the smoke discharge fan through a pipeline, the waste heat recovery section comprises recovery equipment and a chimney, and the chimney respectively communicates with the recovery equipment and the smoke discharge fan through pipelines. According to the continuous annealing and preheating and waste heat recovery system, the energy utilization rate of burning tail gas of aradiant tube can be increased, and the thermal load relation between air injection heating equipment of the preheating section and superheated water equipment of the waste heat recovery section can befully coordinated.

Description

technical field [0001] The invention relates to the field of continuous heat treatment of cold-rolled strip steel, and more specifically relates to a continuous annealing preheating and waste heat recovery system and a flexible control method thereof. Background technique [0002] The heating section of a large vertical continuous annealing furnace generally uses a radiant tube to burn gas to generate heat, and heats the strip steel by radiation, so that a large amount of combustion exhaust gas is discharged from the radiant tube and the exhaust gas temperature is relatively high. Generally speaking, the radiant tube The exhaust gas temperature is 700°C. In order to reduce energy consumption, the traditional practice of continuous heat treatment technology for cold-rolled strip steel is to use a preheating device to preheat it in the strip heat treatment area. However, due to the insufficient capacity of the current preheating furnace, the final exhaust gas temperature is st...

AI Technical Summary

Problems solved by technology

Generally speaking, according to the design requirements, the waste heat recovery equipment 9 has certain restrictions on the flue gas temperature and flow rate. When the heat load in the heating section is high, it may exceed the normal working range of the waste heat recovery equipment. In order to ensure the safety of the equipment, in the pipeline Install a temperature sensor 6 on top, when the temperature of the flue gas is higher than the design requirement, open the valve 2d to supplement the cold air in the part to cool down the flue gas, and a flow meter 7 is installed on the pipeline to test the flow of the flue gas, and when the cold air is mixed in When the flow rate of the flue gas is greater than the design requirement, the bypass valve 2f has to be opened to discharge part of the flue gas into the chimney. Once this happens, it means a huge waste of energy

Analysis of the main reason why the current preheating section and waste heat recovery equipment (the energy recovery of this equipment is generally less than 5%) cannot work fully and effectively at the same time is: the preheating section not only has poor heating capacity, but also poor adjustment ability

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