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Development of Automatic Monitoring Technology for Hydrogen Chloride and Other Components from Stack Emission – Fourier Transform Infrared Spectroscopy Method (FTIR)

Absrtact	It is important to achieve automatic monitoring of target gases (hydrogen chloride and ammonia) in stacks. The relevant local standard methods were not established, but such standards have already been applied abroad for years. This project refer to the relevant standard methods, using a closed-cell FTIR as an analytical instrument to evaluate the application of the stack emission gas monitoring for hydrogen chloride and ammonia, and evaluate the practicality of the method by field tests. Calibration curves were completed in laboratory, including the high concentration HCl (10 ~ 200 ppmv, r2 = 0.9993), low concentration HCl (1 ~ 20 ppmv，r2 = 0.9992), high concentration NH3 (10 ~ 200 ppmv, r2 = 0.9993) and low concentration NH3 (1 ~ 20 ppmv, r2 = 0.9982). The detection limit of HCl was 1.82 ppmv and NH3 was 1.78 ppmv, based on the principle of automatic detection method. The detection limit was 0.176 ppmv for HCl and 0.230 ppmv for NH3, based on the principle of environmental test method. The results of reproducibility test in recovery were 100.17% ~ 103.75% for HCl and 99.96~102.63% for NH3; all met the performance specification of 95~105%. The accuracies (100.74 ± 3.13% for HCl and 101.48 ± 1.88% for NH3) and precisions (1.56% for HCl and 0.95% for NH3) were good while proceeding the test. There were in total 5 field tests and all the results met the checking test requirements, including analyzer calibration error check (<± 2%), sampling system bias (<±5%) and calibration drift test (<± 3%). Checking the spectra from field measurements, there were no target gas absorbance peaks while introducing the zeroing-gas into the analyzer, but the respective peaks appeared while calibration gas was introduced. The hydrogen chloride absorbance peaks also appeared in the spectra of some stack emission gas. The average hydrogen chloride concentrations were variant between 11 ~ 19 ppmv, and the average ammonia concentration were all less than 1 ppmv. The method might be valuable for emission gas monitoring, but the condensation or chemical deposition of reactive HCl and NH3 make it difficult to determine the concentration of the target gas.
Keyword	Stack, Fourier Transform Infrared Spectroscopy, FTIR, Automatic Monitoring Technology

Absrtact

It is important to achieve automatic monitoring of target gases (hydrogen chloride and ammonia) in stacks. The relevant local standard methods were not established, but such standards have already been applied abroad for years. This project refer to the relevant standard methods, using a closed-cell FTIR as an analytical instrument to evaluate the application of the stack emission gas monitoring for hydrogen chloride and ammonia, and evaluate the practicality of the method by field tests. Calibration curves were completed in laboratory, including the high concentration HCl (10 ~ 200 ppmv, r2 = 0.9993), low concentration HCl (1 ~ 20 ppmv，r2 = 0.9992), high concentration NH3 (10 ~ 200 ppmv, r2 = 0.9993) and low concentration NH3 (1 ~ 20 ppmv, r2 = 0.9982). The detection limit of HCl was 1.82 ppmv and NH3 was 1.78 ppmv, based on the principle of automatic detection method. The detection limit was 0.176 ppmv for HCl and 0.230 ppmv for NH3, based on the principle of environmental test method. The results of reproducibility test in recovery were 100.17% ~ 103.75% for HCl and 99.96~102.63% for NH3; all met the performance specification of 95~105%. The accuracies (100.74 ± 3.13% for HCl and 101.48 ± 1.88% for NH3) and precisions (1.56% for HCl and 0.95% for NH3) were good while proceeding the test. There were in total 5 field tests and all the results met the checking test requirements, including analyzer calibration error check (<± 2%), sampling system bias (<±5%) and calibration drift test (<± 3%). Checking the spectra from field measurements, there were no target gas absorbance peaks while introducing the zeroing-gas into the analyzer, but the respective peaks appeared while calibration gas was introduced. The hydrogen chloride absorbance peaks also appeared in the spectra of some stack emission gas. The average hydrogen chloride concentrations were variant between 11 ~ 19 ppmv, and the average ammonia concentration were all less than 1 ppmv. The method might be valuable for emission gas monitoring, but the condensation or chemical deposition of reactive HCl and NH3 make it difficult to determine the concentration of the target gas.

Keyword

Stack, Fourier Transform Infrared Spectroscopy, FTIR, Automatic Monitoring Technology