Abstract:
A system and method for compositional analysis of a process stream in an industrial process transports a liquid process stream through an absorption/desorption packed column (A/D column), along with a carrier gas. A gas phase combination of the carrier gas and one or more solutes from the liquid process stream is passed out of the A/D column to a flow cell for analysis by an analyzer to determine presence and concentration of the one or more solutes within the gas phase. A processor uses the concentration of the solutes within the gas phase to perform a headspace analysis to determine the concentration of the solutes in the process stream.
Abstract:
A method for analyzing fluids, particularly the solute concentration in liquids which are dense or viscous and are only slightly transparent to light, which utilizes an attenuated total reflectance cell with a curved-path optical wave guide, particularly an optical fiber, the wave guide having a portion of its surface interfacing with the fluid to be analyzed. The wave guide has selected dimensions and properties including bend radius, waveguide radius, index of refraction, and effective light path which optimize the measurement. The optimum wave guide dimensions and wavelength of light are selected through calibration of the ATR device with a plurality of fluids of known composition. Light is transmitted through the wave guide and is attenuated by partial reflectance within the wave guide due to absorbance by the fluid being analyzed. The attenuated transmittance is related to optical absorbance, which is correlated directly to concentration of solute.
Abstract:
A stack gas monitor system has an optimized gas flow portion which is permanently installed in a fossil fuel burning facility, and to which a spectrophotometric portion can be readily coupled for real-time determination in the system of a concentration of a first gas having a characteristic absorption spectrum and which is selectably introducible as a measured amount into a stack gas stream. A sample of the stack gas stream is flowing through the gas flow portion, with at least one gas of the sample stream having an absorption spectrum extending within an ultraviolet range of wavelengths of radiation and having absorbance values within this range which are higher than absorbance values of the first gas. The system can be purged and can be calibrated with the first gas. Stack gas blank data are obtained in the absence of the first gas. Composite gas data are provided upon introduction of the first gas into the stack gas. Absorbance values for the first gas in the composite gas are calculated, and first gas concentration levels are determined and are monitored on a periodic basis.
Abstract:
An improved rapid-scan spectrophotometer with an optical grating continuously rotating at a constant angular velocity. An optical trigger actuated by the rotating turntable supporting the grating, actuates an analog to digital converter to sample at discrete times an output signal from the sample detector over the desired wavelength range and to store the digitized information in a direct memory access (DMA) buffer. The information may be retrieved as desired from the buffer for further processing or permanent data storage. With each revolution of the optical grating, the range (typically 15.degree.) of wavelengths from the grating that provides useful information is sampled by the analog to digital converter and stored in the buffer. Because the grating is continuously rotating at a constant angular velocity and is not limited by the inertia of optical components, the spectrophotometer can be operated at a much higher scanning speed than an oscillating or vibrating grating spectrophotometer.
Abstract:
A spectrometer includes a light source, a fiber optic bundle with a first and second leg, where the first leg has more fibers than the second leg, a flow cell, focusing optics, a disperser, and a detector. The spectrometer may also include a mask and system electronics to control the spectrometer. The spectrometer allows for simultaneous dual analysis of a reference and sample beam and minimizes errors and attenuations in the signals. The elimination of mechanical moving parts and control of attenuation losses enables less sophisticated control electronics to be utilized.
Abstract:
A system for rapid-scan spectral analysis comprising a concave holographic diffraction grating continuously rotated at a substantially constant angular velocity to provide a rapid scanning monochromator (a monochromator is used to transfer nominal regions of wavelengths out of the continuous light source). The unique sampling circuitry uses an optical shaft encoder. The angular velocity and angular acceleration of the grating are calculated from time measurements, just before the first wavelength of interest falls on the detector. This information is used to control the Analog to Digital converter sampling rate across the region of interest. The samples as a function of time are stored in a memory buffer so that each data point corresponds to a wavelength.