Battery-Powered, Differential Infrared Absorption Sensor for Methane, Ethane, and Other Hydrocarbons

摘要

This report presents the performance goals, design considerations, and physical details of the miniature infrared absorption sensor being developed for the US DOE's Liquefied Natural Gas Spill Safety Program. The sensor is lightweight, battery-powered, portable, self-contained, and able to interface readily to large-array data systems. Essentially a precision infrared differential spectrometer capable of operating over the full range of gas concentrations expected in the spill diffusion tests, the sensor is expected to cost less than $7000 per unit. The present design of this open-cell, fast-response sensor allows it to measure two components, but it can be modified to measure additional components at a reduced sampling frequency. To minimize temperature effects and power consumption, the sensor has a single-source, single-detector design which includes a rotating chopper-filter wheel. A CMOS microprocessor interfaced with a fast arithmetic chip is used to linearize sensor output and correct for component interference. (ERA citation 05:004037)