TDLAS based escaped ammonia concentration detection device and method

Abstract

The invention discloses a TDLAS based escaped ammonia concentration detection device and method. The device comprises a microprocessor, a current control circuit, a temperature control circuit, a feedback control circuit, a laser, a collimator, an optical gas chamber, a photoelectric detector, a data processing circuit and a display circuit, wherein the output ends of the current control circuit and the temperature control circuit are connected with the input end of the laser, the output end of the photoelectric detector is connected with the output end of a pre-amplification circuit, and the output end of the microprocessor is connected with the input ends of the current control circuit, the temperature control circuit and the feedback control circuit. According to the invention, the absorption peak position of ammonia gas can be locked accurately and quickly without a reference gas chamber, so that the development cost of an escaped ammonia monitoring device is saved, optical noise generated when light rays pass through an optical fiber splitter can be avoided, the signal to noise ratio of a system is improved, and the accuracy of an escaped ammonia concentration detection result can be improved greatly.

Description

technical field [0001] The invention relates to the field of detection of escaped ammonia concentration, in particular to a device and method for detecting the concentration of escaped ammonia based on TDLAS technology. Background technique [0002] Coal and other fossil fuels will emit a large amount of nitrogen oxides (NOx) pollutants during the combustion process. NOx emissions into the air can form acid rain and photochemical smog, etc., which bring great harm to people's production and life. Coal generating units and coal-fired boilers are equipped with selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) flue gas denitrification devices to reduce NOx emissions; the principle of SCR / SNCR method is to use liquid Ammonia or ammonia water is injected into the denitration device as a reducing agent, and ammonia gas (NH 3 ), the ammonia gas and the NOx in the flue gas undergo a reduction reaction to generate harmless N 2 and H 2 O. However, in ...

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Problems solved by technology

[0005] According to the above method, each gas analysis instrument based on TDLAS technology needs to be equipped with a beam splitter and a reference gas chamber; however, on the one hand, when the light passes through the beam splitter, optical noise will be generated, which will reduce the signal-to-noise ratio of the system and seriously affect the gas Concentration measurement results; on the other hand, the reference gas chamber needs to be heated and evacuated during the manufacturing process to remove pollutants. In addition, each reference gas chamber needs to pass the helium leak test to ensure the service life Therefore, the manufacturing process of the reference gas chamber is very difficult, and the market price is expensive, which not only increases the cost of use, but also is not conducive to the promotion and application of the product

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