Fiber optic sensing system for temperature and gas monitoring in coal waste pile combustion environments

Duarte Viveiros ,A Lopez-Albada,A M R Pinto,J L Santos,J M Baptista,Alejandro Domínguez-López ,Susana Silva ,Deolinda Flores ,Orlando Frazão ,Óscar Esteban ,Alexia López-Gil ,Sonia Martín‐López ,Miguel Gonzalez-Herraez ,Joana Ribeiro ,Sébastien Rougier ,Raphaël Jamier ,João José Pinto Ferreira ,Silvia Díaz ,Philippe Roy ,Rosa Ana Pérez-Herrera ,M Lopez-Amo,J.-L Auguste

doi:10.1117/12.2195088

Abstract

It is presented an optical fiber sensing system projected to operate in the demanding conditions associated with coal waste piles in combustion. Distributed temperature measurement and spot gas sensing are requirements for such a system. A field prototype has been installed and is continuously gathering data, which will input a geological model of the coal waste piles in combustion aiming to understand their dynamics and evolution. Results are presented on distributed temperature and ammonia measurement, being noticed any significant methane emission in the short time period considered. Carbon dioxide is also a targeted gas for measurement, with validated results available soon. The assessment of this technology as an effective and reliable tool to address the problem of monitoring coal waste piles in combustion opens the possibility of its widespread application in view of the worldwide presence of coal related fires.

Highlights

The occurrence of coal related fires is known all over the world and is associated with coal mining, disposal of coal mining residues, coal transportation, and coal storage
Proc. of SPIE Vol 9634 96343Y-1 it is presented a brief description of this coal deposit, the structure of the fiber optic sensing system developed and, results relative to the measurement of distributed temperature and gas emission are delivered
A comprehensive set of temperature measurements in the coal waste pile were accomplished over several weeks

Summary

INTRODUCTION

The occurrence of coal related fires is known all over the world and is associated with coal mining, disposal of coal mining residues, coal transportation, and coal storage. Multi-point and continuous measurement of combustion temperature and gaseous emissions in self-burning waste piles, a R&D INTERREG-SUDOE project entitled ECOAL-MGT- (“Ecological Management of Coal Waste Piles in Combustion”) is being developed, with participation of groups from Portugal, Spain and France. In this project, a fiber sensing system is being used for the first time in this environment. Pedro da Cova coal waste pile resulted from the past mining activities in Douro Coalfield and started burning in 2005 after intense forest fires in the region, which caused their ignition This waste pile has an area of approximately 28 000 m2 and is located close to the oldest center of mining activities in S. Pedro da Cova coal waste pile (red contour), showing: i) region of distributed temperature measurement (yellow line); ii) gas measurements spots (green points); iii) optical fiber cable path to the central office; iv) installation of the fiber optic cable for distributed temperature measurement (right, top); v) installation of one of the boxes to accommodate the gas sensors (right, middle)

OPTICAL FIBER SENSING SYSTEM

RESULTS

CONCLUSIONS