Multiplexed Sensor for Synthesis Gas Compsition and Temperature

Abstract

The overall goal of this project has been to develop a highly sensitive, multiplexed TDL-based sensor for CO 2 , CO, H 2 O (and temperature), CH 4 , H 2 S, and NH 3 .Such a sensor was designed with so-called "plug-and-play" characteristics to accommodate additional sensors, and provided in situ pathintegrated measurements indicative of average concentrations at speeds suitable for direct gasifier control. The project developed the sensor and culminated in a real-world test of the underlying technology behind the sensor. During the project, new underlying measurements of spectroscopic constants for all of the gases of interest performed, in custom cells built for the project. The envisioned instrument was built from scratch from component lasers, fiber optics, amplifier blocks, detectors, etc. The sensor was tested for nearly a week in an operational power plant. The products of this research are expected to have a direct impact on gasifier technology and the production of high-quality syngas, with substantial broader application to coal and other energy systems. This report is the final technical report on project #DE-FG26-04NT42172. During the project we completed all of the milestones planned in the project, with a modification of milestone (7) required due to lack of funding and personnel.UCSD / Buckley #DE-FG26-04NT42172Final Technical Report p4 2. Executive SummaryThis project was to design, build, and test an integrated sensor that could be used to measure and control the products of coal gasification. The first milestone completed was the selection of experimental parameters, particularly the wavelengths for measurement of the desired species (H 2 O, CH 4 , CO, CO 2 , H 2 S, and NH 3 ). This was accomplished using software databases, careful inspection for interferences, particularly from hot H 2 O bands, and the availability of laser sources.The design and construction milestones involved hardware design choices, followed by assembling and testing of hardware. The sensor design and construction milestones were completed in the first year of the project, as planned.The measurement of temperature-and pressure-dependent spectroscopic parameters for the molecules and specific transitions of interest were monumental, time-consuming tasks. For these measurements, several long-path spectroscopic cells (one high pressure, one atmospheric and lower-pressure, two all-glass cells) were designed and built. Full spectroscopic understandingmeasurement of all of the relevant pressure broadening and line strength parameters at a range of pressures from 0-10 bar and temperatures up to 800 K was achieved for the CO, CO 2 , CH 4 , and H 2 O transitions selected for the sensor. Detailed and difficult similar measurements were also completed for NH 3 . Based on these measurements, highly accurate concentration measurement of these five gases is possible. Based on a more limited set of parameter measurements, qualitative measurement of H 2 S is also possible. The gas-handling requirements related to the toxicity of ...