Device and method for detecting sulfur trioxide in flue gas on line

Abstract

The invention discloses a device and a method for detecting sulfur trioxide (SO3) in flue gas on line. The device comprises a flue gas collecting unit, a gas liquid separator, a gas phase detection unit, a first solution tank, a liquid phase detection unit and a digital control unit, wherein the gas liquid separator is used for condensing SO3 in the flue gas from a flue gas sampling unit into sulfuric acid liquid drops and separating the sulfuric acid liquid dropsfrom gas phase; the gas phase detection unit is used for measuring the flow of the gas phase from the gas liquid separator; the first solution tank is used for providing an absorption liquid to the gas liquid separator and mixing the absorption liquid with the sulfuric acid liquid drops to form mixed liquid; the liquid phase detection unit is used for measuring the mass of the transformed SO3 in the mixed liquid from the gas liquid separator; and the digital control unit is used for calculating the SO3 concentration of the flue gas according to the detection results of the gas phase detection unit and the liquid phase detection unit. According to the device and the method, on-line measurement of the SO3 of the flue gas is realized, the SO3 of the flue gas is sampled and the SO3 content is analyzed, so that a coal-fired power plant can take corresponding measures conveniently, the SO3 content of the flue gas is controlled, the corrosion to a flue and equipment is reduced, and the heat loss due to exhaust smoke of a boiler is reduced to the maximum degree.

Description

technical field [0001] The invention relates to the technical field of flue gas treatment, in particular to an online detection device and method for sulfur trioxide in flue gas. Background technique [0002] Currently thermal power plant SO 3 Although the emissions are very small, due to SO 3 It is easy to combine with water vapor in the flue gas to form sulfuric acid vapor, which condenses on the heating surface whose wall temperature is lower than the acid dew point, causing acid dew point corrosion. SO in flue gas 3 , the more content, the higher the acid dew point temperature, the wider and more serious the corrosion range. In recent years, more and more power plants in my country have installed wet flue gas desulfurization. Due to the high humidity of the net flue gas after wet desulfurization, the residual SO in the flue gas 3 It is very easy to quickly convert into sulfuric acid droplets, causing serious corrosion to the flue and downstream equipment. SO in exha...

AI Technical Summary

Problems solved by technology

There is no measurement part in the patent, and online measurement cannot be realized

[0007] The invention patent with the patent number 20091021169.1 discloses a method for detecting, measuring and controlling SO in flue gas 3 And other methods and devices for condensables can measure the concentration of various condensables, but this method requires high accuracy of materials and cannot achieve online continuous measurement

In the United States, a SO is disclosed in Patent No. 2011 / 0097809 3 The measurement method has high precision, but the device is inconvenient to carry and is suitable for laboratory operation

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