Method for preventing flue gas dew-point corrosion of exhaust heat recovery apparatus

Abstract

The invention discloses a method for preventing a waste heat recovery device from flue gas dew point corrosion, which aims to solve the problem that the prior method has a danger of making the waste heat recovery device produce the flue gas dew point corrosion. The method comprises the following steps: A, an acid dew point measurement instrument (1) is used to measure a flue gas acid dew point temperature Tm at a flue gas outlet of the waste heat recovery device and transmits the Tm to a comparator (3), and a wall surface temperature transmitter (2) is used to measure a flue gas side wall surface temperature Tgm of a heat transfer element close to the flue gas outlet, and also transmits the Tgm to the comparator; B, the comparator adds the Tm by minimum excess temperature difference dTmin (5-10 DEG C), compares the sum of the Tm and the minimum excess temperature difference dTmin (5-10 DEG C) with the Tgm to obtain regulation temperature difference delta Tgm, and transmits the delta Tgm to a temperature regulator (4); and C, the temperature regulator produces and outputs a heat exchange amount adjustment signal, controls a heat exchange amount adjustment device to actuate, and regulates the heat exchange amount of the waste heat recovery device to ensure that the Tgm is 5 to 10 DEG C higher than the Tm, therefore, the flue gas dew point corrosion is avoided.

Description

technical field [0001] The invention relates to a method for avoiding flue gas dew point corrosion in a waste heat recovery device in the field of industrial furnace waste heat recovery. Background technique [0002] In petrochemical, electric power, steel and other industries, reducing the flue gas discharge temperature of industrial furnace waste heat recovery device is a main way to improve the thermal efficiency of industrial furnaces. With the lack of energy and the rise of fuel prices, the exhaust temperature of industrial furnaces is getting lower and lower. Because the fuel contains a certain amount of sulfur or sulfide, when the temperature of the flue gas side wall surface of the heat transfer element near the flue gas outlet of the waste heat recovery device of the industrial furnace is lower than or equal to the acid dew point temperature of the flue gas, the waste heat recovery device (mainly Heat transfer elements, such as heat transfer tubes or heat transfer ...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for avoiding flue gas dew point corrosion in a waste heat recovery device, so as to solve the problem that the set temperature for preventing flue gas dew point corrosion on the flue gas side wall of the heat transfer element cannot be accurately determined and cannot be solved in the existing method. It is adjusted according to the change of the acid dew point temperature of the exhaust flue gas, so that the waste heat recovery device has the problem of flue gas dew point corrosion

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