Development of All-Solid-State Sensors for Measurement of Nitric Oxide and Carbon Monoxide Concentrations by Optical Absorption

EPA Grant Number: R828180
Title: Development of All-Solid-State Sensors for Measurement of Nitric Oxide and Carbon Monoxide Concentrations by Optical Absorption
Investigators: Walther, Thomas , Caton, Jerry , Lucht, Robert P.
Institution: Texas A & M University
EPA Project Officer: Shapiro, Paul
Project Period: July 1, 2000 through June 30, 2002
Project Amount: $225,000
RFA: Exploratory Research - Engineering, Chemistry, and Physics) (1999) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Water , Land and Waste Management , Air , Engineering and Environmental Chemistry

Description:

The objective of this research is the development of new optical sensors for the detection of nitric oxide (NO) and carbon monoxide (CO) in the exhaust streams of combustion systems. Sensors based on absorption measurements combine high sensitivity and real-time capabilities. Present sensors rely on physical sampling techniques which are inherently slow.

The specific objectives of this research are:

  1. The development of a fiber-amplified, diode laser based UV optical sensor for NO measurements and mid-infrared sensor for CO measurements.

  2. Characterization of the performance of the sensors by absorption measurements in a gas cell, simulated combustion exhaust streams, and a well-characterized flame, and by comparison with Fourier Transform Infrared (FTIR) measurements and probe sampling.

  3. Completion of a feasibility study of the incorporation of the sensor systems in practical systems for pollutant monitoring and control.

Approach:

The sensors for NO and CO are based on absorption measurements in the UV (NO) and mid-infrared frequency (CO) regions. The optical sensor for NO is based on a sequence of frequency-conversion steps to obtain tunable ultraviolet laser radiation from the output of two infrared external-cavity diode laser (ECDL) systems of approximately 1064 nm and 1535 nm amplified by the use of fiber amplifiers.

The optical sensor for carbon monoxide is based on frequency difference mixing of the fiber-amplified radiation from ECDL systems operating at approximately 1017 nm and 1308 nm in a periodically poled Lithium Niobate crystal.

Expected Results:

The proposed research will produce new optical sensors for nitric oxide and carbon monoxide that are at least 2 orders of magnitude more sensitive than previous sensors. In addition these sensors will be capable of real-time measurements and could be used for combustion control applications.

Improvement in Risk and Risk Assessment and Risk Management: Because of its role in the chemistry of photochemical smog, nitric oxide (NO) is one of the most important pollutant species emitted by practical combustion devices. It is subject to increasingly stringent environmental regulations, and because of this billions of dollars are spent every year by manufacturers of automobiles, aircraft engines, power generating gas turbines and other practical combustion devices to control NO emissions. Due to their increased sensitivity and real-time capability our sensors will enable on the one hand capability to enforce these stricter emission standards and on the other hand make combustion control applications with the goal of reduced pollutant emission possible.

Publications and Presentations:

Publications have been submitted on this project: View all 13 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 2 journal articles for this project

Supplemental Keywords:

pollutant monitor, pollutant emissions, diode lasers, optical sensors, nitric oxide, carbon monoxide, fiber amplifiers, RFA, Scientific Discipline, Air, Toxics, Waste, Environmental Chemistry, Physics, HAPS, Environmental Monitoring, tropospheric ozone, Engineering, Chemistry, & Physics, EPCRA, Incineration/Combustion, Fourier Transform Infrared measurement, air quality standards, fiber ampiliers, risk assessment, nitrous oxide, combustion systems, pollutant monitoring, probe sampling, carbon monoxide (CO), air sampling, ambient emissions, chemical detection techniques, smog, carbon monoxide, laser based optical sensor, Nitric oxide, nitric oxide (NO), combustion, diode laser, diode laser spectrometer, optical absorption

Progress and Final Reports:

  • 2001
  • Final Report