On-line continuous detection device for ammonia in gas using chemical spectrophotometry

Abstract

The invention discloses an on-line continuous detection device for ammonia in gas using chemical spectrophotometry, comprising: a particulate filter, which is arranged at the gas inlet end; a sampling pipe, which is connected with the outlet of the particulate filter; a mixer, which is connected to the outlet of the particulate filter. The outlet of the sampling pipe is connected, and the liquid inlet of the mixer is connected with one end of the absorption liquid circulation pipe; the new absorption liquid storage bottle is connected with the liquid inlet of the mixer through the new absorption liquid replenishing pump; the absorption liquid circulation pump, which is connected with the bottom of the absorption bottle; ammonia absorption pipe, one end of which is connected with the liquid outlet of the mixer, and the other end is connected with the inlet of the absorption bottle; gas-liquid separator, which is connected with the gas outlet at the top of the absorption bottle It is connected with the gas dehydrator, mass flow meter and gas pump in sequence through pipelines; the rich liquid concentrator and the rich liquid diluter are connected in parallel. The on-line continuous detection device for ammonia in gas of the present invention uses chemical spectrophotometry to monitor the ammonia concentration in the gas, and realizes the on-line continuous monitoring of ammonia.

Description

technical field [0001] The invention belongs to the technical field of environmental protection monitoring, and relates to a continuous detection device for ammonia in gas by absorption method, in particular to an online continuous detection device for ammonia in gas by chemical spectrophotometry. Background technique [0002] With the acceleration of thermal power construction in China, the control of NOx emissions from coal-fired power plants has become the top priority of the power industry's environmental protection work. Flue gas denitrification technology is one of the main methods to control nitrogen oxide emissions in my country. At present, the technologies that are widely used at home and abroad and have mature technology are selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) flue gas denitrification. Among them, selective catalytic reduction (SCR) technology is currently the mainstream technology for flue gas denitrification, account...

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Problems solved by technology

Chinese patent application number 201510638435.3 discloses an online ammonia escape concentration measurement device and measurement method based on liquid absorption method. The patent analyzes the defects of the laser measurement method, but does not specify how the patent can efficiently and accurately detect ammonia escape

[0005] Laser in situ measurement enables real-time monitoring of NH 3 However, the disadvantages of this method are: ①The measurement results are greatly affected by factors such as smoke concentration in the flue, flue vibration, flue gas temperature and pressure fluctuations, and this method cannot be calibrated online, so the accuracy of the measurement results cannot be verified ; ② Due to the direct measurement method, there are many factors that affect the measurement results, and the stability of the measurement data cannot be guaranteed; ③ The optical devices are easy to be polluted, and due to the influence of flue vibration, thermal expansion and contraction, etc. Adjustment and Maintenance

Chinese patent application number 201510201370.6 discloses an online detection device and method for escaped ammonia by gas-liquid transfer method. In this patent, ammonia gas enters the absorption liquid after drying and gas-liquid separation, and the mass concentration of ammonia nitrogen is measured by a water quality ammonia nitrogen sensor. However, due to the characteristics of ammonia gas being easily adsorbed and soluble in water, it is easy to adsorb in the desiccant, resulting in low measurement results

At the same time, the water quality ammonia nitrogen sensor is a multi-parameter chemical sensor, which is composed of a temperature sensor, a pH electrode, and an ammonia gas sensitive electrode. The disadvantages of ammonia gas-sensing electrodes are analyzed in "Research on Escaped Ammonia Detection System": poor selectivity and stability, greater influence by the environment, and the electrode method has higher requirements on the sample environment, electrode state and maintenance

However, the SKALAR continuous flow analyzer is only used for automatic laboratory analysis, and further research is needed for the online continuous analysis of ammonia in flue gas

[0008] In summary, none of the existing ammonia on-line analyzers can solve the problem of ammonia detection in flue gas and air well, and it is urgent to develop a new online continuous ammonia detection device and method

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