NSF Award
9211764
Characterizing the particle size distribution, concentration, and temperature within an aerosol reactor is essential to the proper understanding and control of the process. Phase I research has demonstrated a novel Fourier transform infrared (FT-IR) emission/transmission (E/T) techniques to address the above problems for the synthesis of TiO particles. TiO particles strongly absorb at wavenumbers less than 1000/cm, and thus the measured extinction is directly proportional to the particle mass. In contrast, extinction above 1000/cm is due to scattering and is a strong function of the particle size distribution. Using Mie theory, one can deconvolute extinction spectra to estimate the geometric mean diameter within 10% of its actual value. In addition to particle mass and size, E/T FT-IR can also simultaneously measure particle temperature as well as gas concentrations and temperature. This Phase II project will develop an instrument for on-line in- situ analysis of submicron sized particles. This research will (1) develop improvements to the FT-IR and procedures to optimize the acquisition of transmission and emission data, (2) improve and extend the theory relating measured transmission spectra to particle size, (3) evaluate the instrument and analysis software by comparing the IR deconvolution to other particle sizing techniques, and (4) field test the instrument and software on a commercial TiO2 production facility. This proposal combines the expertise of three key organizations: (1) Advanced Fuel Research provides its extensive knowledge of FT-IR technology; (2) Prof. Hemant Pendse (University of Maine) is an expert in the deconvolution of particle size distributions from attenuation spectra; and (3) Prof. Sotiris Pratsinis (University of Cincinnati) will evaluate the FT-IR results and compare them to conventional particle sizing techniques. The above instrument will perform size measurements of aerosols as well as measuring particle mass, particle temperature, gas composition, and gas temperature. The instrument will be rugged, user friendly, portable, and relatively inexpensive. The applications for such an instrument include the synthesis of catalyst supports, sinterable ceramics, metal particles, optical materials, and electronic materials.
