Method for overheating steam of cooler waste heat boiler and device used in same

Abstract

The invention discloses a method for overheating steam of a cooler waste heat boiler by using tail smoke gas waste heat of a sintering machine and a device used in the same. The device comprises a chimney, a spindle fan, a sintering machine, a large-flue dust remover, a cooler, a cooler dust remover, a sintering machine large flue, a cooler waste heat boiler, a sintering smoke gas heat exchanger, a heat user, and the like. The method mainly comprises the step of feeding the steam of the cooler waste heat boiler to the heat user via the high-quality steam formed by the sintering smoke gas heat exchanger. The method for overheating steam of the cooler waste heat boiler by using tail smoke gas waste heat of the sintering machine improves the amount and the quality of steam at the outlet of the waste heat boiler and avoids low-temperature corrosion produced in the heat exchanging process as the temperature of the steam at the inlet of the heat exchanger is far greater than that of an acid dew point of the sintering smoke gas.

Description

technical field [0001] The invention relates to the field of waste heat utilization of sintering process in the iron and steel industry, in particular to a method for superheating the waste heat boiler steam of a cooling machine by utilizing the waste heat of tail flue gas of a sintering machine and a device used therefor. Background technique [0002] The iron and steel industry is one of the industrial sectors with the largest energy consumption, and the energy consumption of the sintering process accounts for about 10% of the total energy consumption in the steel production process, ranking second only to the iron-making process. The waste heat resources in the sintering process are mainly composed of two parts: the sensible heat of sintering ore from the cooling machine, that is, the cooling waste gas, and the sensible heat of the sintering waste gas from the sintering machine, that is, the sintering waste gas. The temperature of the cooling waste gas varies from 100 to ...

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Problems solved by technology

[0003]Since most of the cooling waste gas is composed of air, there is almost no corrosive gas and impurities after dust removal by the dust collector, so many domestic sintering plants use high temperature to cool the waste gas, Entering the waste heat boiler to generate steam, but because the temperature and flow rate of this part of the exhaust gas are not very high, the steam generated after entering the waste heat boiler has a low degree of superheat, low quality, and the steam flow rate is not large. If this part of steam is used to generate electricity, due to the Poor working ability, high steam consumption for power generation, low power generation output, and poor economy. If it is incorporated into the pipeline network, the poor quality of steam will also affect the economy

However, the sintering flue gas at 300-400°C at the tail of the sintering machine has a relatively small quantity, low quality, and complex composition, which contains SO2, NOX Impurities such as sub> and dust directly affect the recovery of this part of heat, so many domestic sintering plants do not use this part of heat, but directly mix it with low-temperature sintering waste gas and discharge it directly through a large flue, which wastes heat energy and pollutes the environment

Even if the sintering waste heat boiler is used to recover this part of the heat, the addition of the sintering flue gas waste heat boiler will increase the equipment cost and complicate the process, and because there will be SO 2 , NO X Corrosive gases such as corrosive gases will inevitably cause low-temperature corrosion. According to relevant literature reports, after low-temperature corrosion occurs on the low-temperature heating surface of a waste heat boiler, the pin ribs at the low-temperature corrosion will be corroded from φ6 to φ1.5. The life of the air preheater is shortened to 4-5 years, and after low-temperature corrosion, it will also cause ash blocking, which will increase the flue gas resistance sharply (it can be increased by more than 1-2 times), overload the fan, and limit the output and output of the boiler. The operation period is shortened, and the boiler is even forced to shut down. If the corrosion is severe, the tube will be perforated and the working medium will leak. Therefore, the occurrence of low-temperature corrosion seriously affects the safety and economy of the boiler operation.

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