Laser spectroscopic investigation of formation and conversion of isocyanic acid during the aftertreatment of combustion exhaust gases

该项目旨在开发一种基于吸收的激光光谱仪，用于选择性测量燃烧过程（即发电厂）废气中的HNCO（异氰酸）。光谱仪将用于研究废气混合物、添加剂喷射（定时、数量、几何形状）以及流动条件（偏差、横截面、湍流）的影响。为了增加在最近的燃烧系统中进一步减少污染物的潜力，有必要提高对燃烧过程中的化学过程以及废气后处理的理解。为了获得更多的信息，废气成分与高的时间分辨率，需要一个更好的诊断。因此，在本项目中，将开发一种用于燃烧过程废气中HNCO原位测量的光谱仪。为了调查总体污染物含量，光谱仪具有高时间分辨率（ms）和高灵敏度以及选择性。基于近红外和中红外光谱区的可调谐二极管激光吸收光谱（TDLAS），光纤技术的最新进展将与新开发的多程池（改进的白色设计）一起使用，以使光谱仪适应高温过程。此外，基于FTIR的HNCO光谱线数据（线强度，线增宽）的测量将完成，以实现从TDLAS测量中准确提取HNCO摩尔分数。

The project aims on the development of an absorption based laser spectrometer for the selective measurement of HNCO (isocyanic acid) in the exhaust of a combustion process (i.e. power plant). The spectrometer will be used to investigate the influence of the exhaust gas mixture, the additive injection (timing, quantity, geometry) as well as the flow conditions (deviation, cross section, turbulence).To increase the potential for further pollutant reduction in recent combustion systems it is necessary to improve the understanding of the process chemistry during combustion as well as exhaust aftertreatment. To get more information about the exhaust gas composition with high temporal resolution, a better diagnostic is needed. Therefore, within this project, a spectrometer for the in situ measurement of HNCO in the exhaust of a combustion process will be developed. To investigate the overall pollutant content, the spectrometer measures with high temporal resolution (ms) and highly sensitive as well as selective. Based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) in the near as well as middle infrared spectral region, recent progresses in the fiber-technology will be used together with a new developed multi-pass-cell (modified White design) to adapt the spectrometer to the high-temperature process. Additionally, FTIR based measurements of the spectroscopic line data of HNCO (line strength, line broadening) will done to realize the accurate extraction of HNCO-mole fractions from the TDLAS measurements.