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Resumen

 

20 PPB’S BENZENE DETECTION IN A CO2 FLOW USING A SEMICONDUCTOR GAS SENSOR MATRIX AND A THERMAL DESORTION SYSTEM

DETECCION DE 20 PPB’S DE BENCENO EN UN FLUJO DE CO2 USANDO UNA MATRIZ DE SENSORES DE GASES SEMICONDUCTORES Y UN SISTEMA DE DESORCION TERMICA
PhD. Christian M. Durán Acevedo.
PhD. Jesús Brezmes Llecha.

Abstract: A novel multisensor system including a thermal desortion unit was built to detect Benzene traces in a CO2 flow. The desortion system uses an "Carbopack B" unit which adsorbe Benzene traces in 10 minutes and later, by means of a current pulse, and through a 50 ml/min of the carrier flow are thrown toward the sensors chamber for its respective detection. The system is able to classify Benzene samples below 20 ppb's (parts per billion) in a CO2 flow with purity superior to 99.95% and with diverse volatile
interferences. A concentration factor bigger than 200 was obtained, can be say that it is the first time that such a system has been designed.

Resumen: Un novedoso sistema multisensor incluyendo una unidad de desorción térmica fue construido para detectar trazas de Benceno en un flujo de CO2. El sistema de desorción utiliza una unidad de “Carbopack B” el cual adsorbe trazas de Benceno en un tiempo de 10 minutos y después por medio de un pulso de corriente y a través de un flujo de 50 ml/min del portador son lanzados hacia la cámara de sensores para su respectiva detección. El sistema es capaz de clasificar muestras de Benceno por debajo de 20 ppb’s (partes por billon) en un flujo de CO2 con una pureza superior al 99.95% y con diversas interferencias volátiles. Se obtuvo un factor de concentración mayor de 200, se puede decir que es la primera vez que se ha diseñado tal sistema.

Keywords: Quality control, CO2, Gas sensors, Pattern recognition, Electronic smelling system.