Infrared Spectroscopy for Online Measurement of Tars, Water, and Permanent Gases in Biomass Gasification

Abstract

Online measurements of the raw gas composition, including tars and water, during biomass gasification provide valuable information in fundamental investigations and for process control. Mainly consisting of hydrocarbons, tars can, in principle, be measured using Fourier transform infrared (FT-IR) spectroscopy. However, an instrument subjected to raw gas runs the risk of condensation of tars on optical components and subsequent malfunction. Therefore, an external cell, heated to at least 400 ℃, has been designed to ensure that tars remain in the gas phase during FT-IR measurements. The cell was used for on-line FT-IR measurements of permanent gases (CO, CO2, CH4), water, and tars during the operation of a lab-scale downdraft gasifier using wood pellets, bark pellets, and char chips. Based on calibration, the measurement error of permanent gases was estimated to be 0.2%. Concentrations evaluated from spectral signatures of hydrocarbons in tar are in good agreement with results from solid-phase adsorption measurements and correlated well with operational changes in the gasifier.

Optofluidic Platform for Rapid On-Chip Analysis of Total Phosphorus in Surface Water Using Absorption Spectrometry

“…[2][3][4][5] In contrast, spectral analysis possesses the merits of high sensitivity and accuracy, simple operation, fast response, and so on. 6,7 Therein, absorption spectrometry has been adopted by the Chinese National Standard (GB 11893-89) to determine the content of some ions and organic pollutants in drinking water, surface water and industrial wastewater. However, traditional methods with poor combination between biochemical reactions and optical detection usually involve complex manual operation for water samples pretreatment, which is time-consuming (usually several hours) and easy to bring uncertainties.…”