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An on-line carbon-in-ash monitor based on in-situ infrared emission spectrometry is described. Laboratory measurements of the infrared spectral emissivity of flyash are presented in order to demonstrate that emissivity can be correlated to the residual carbon content in the range of interest for pulverized coal-fired power plants. Data collected during a field test at a pilot-scale combustor are presented in order to demonstrate that the emissivity measurements could be made in situ on a realistic facility, and that the spectral emissivity could be correlated to the residual carbon content. Since this measurement can be made in-situ in a few seconds using an FT-IR spectrometer, an infrared emissivity based carbon-in-ash monitor will be capable of providing data on a time scale appropriate for implementation in combustion control strategies while avoiding the disadvantages associated with extractive ash sampling.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Recently, infrared transmitting optical fibers have been employed for remote spectral analysis of processes such as composite curing and polymerization of polyurethane. By imbedding the fiber in the sample, spectra can be obtained by measuring the attenuation of the evanescent wave that penetrates into the sample. This method, fiber optic attenuated total reflectance (FO/ATR), provides a minimally invasive technique for probing the chemistry occurring inside the sample during processing. The purpose of this work is to extend FO/ATR to the analysis of harsh liquid process streams that are difficult to monitor using other techniques.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The development of diagnostic instrumentation for monitoring coal liquefaction process streams is discussed. A sapphire optical fiber was used as an attenuated total reflectance (ATR) element in conjunction with Fourier transform infrared (FT-IR) spectrometry to probe harsh liquefaction process streams. ATR provides a short, reproducible pathlength which allows for the analysis of highly absorbing materials, such as liquid hydrocarbons, and the properties of sapphire are well suited for the analysis of high temperature and high pressure process streams. A test cell was constructed which allowed in-situ monitoring of coal liquefaction reactions at 400 degree(s)C and 3000 psig. The cell incorporated a sapphire optical fiber as an ATR sensing element which was coupled to an FT-IR spectrometer using zirconium fluoride fiber optic cables. The spectra provide qualitative information about the liquefaction process.

been hindered by the lack of reliable instrumentation and test methods to evaluate these fuels.This paper describes the use of an insitu FT-JR fiber optic probe to monitor the growth andcomposition of deposits from thermal stressing of jet fuel A high temperature (500°C), highpressure (700 psig) heated flow cell was constructed and equipped with a sapphire fiber as anAttenuated Total Reflectance (ATR) element. At the outlet of the system, a Spectra Tech ATR

An important requirement in many industries is the ability to perform on-line monitoring and control of harsh, multi-phase process streams. During the last ten years, significant progress has occurred in the hardware and applications for Fourier transform infrared (FT-IR) spectroscopy. Instrumentation is now available which can perform, in harsh environments, continuous unattended and simultaneous measurements of absorbed (or reflected) and emitted radiation. The applications of FT-IR include: (1) concentrations of multiple species and phases (gases, liquid, particles, surfaces) as low as ppb; (2) temperatures of multiple species and phases (gases, liquid, particles, surfaces) with accuracies as good as +/- 1 degree(s)C at any elevated temperature; (3) measurement of particle sizes; (4) measurement of film thickness; (5) in-situ line-of-sight data; (6) in-situ spatially resolved data using tomography; (7) data on extracted samples; and (8) data on time scales as short as a few milliseconds.