ADJUSTMENT OF AUTOMATED EMISSION MONITORING SYSTEMS

ABSTRACT

For continuous control of large sources automated emission monitoring systems for dust and different gaseous pollutants are used. These analysers have to be calibrated, depending on the national regulations after the installation and in regular intervals by means of independent reference methods, e.g. every three years. During the intervals of calibration and functional controls the operator has to maintain his analytical equipment for himself. One of these tasks is adjustment of analysers. All analysers are no absolute measuring systems. Generally drifting of zero and span (reference point) can be noticed. The stability of different systems can vary considerably. Therefore it is necessary to adjust zero and span point of analysers in regular intervals. This paper describes systems for adjustment of dust and gas analysers. It starts for gas analysers with conventional manual technique with span gases followed by automated systems still using span gases and describes modern systems according different principles, e.g. analysers only with adjustment of zero or systems working with cuvettes, filled with the gas to be measured. The results of long term studies of these systems are reported.

1. INTRODUCTION

Continuous emission monitoring - from the instrumentation point of view - is derived from the measurement technology for operating analyses. In this area continuous gas analysis processes had already been developed, even before any legally-specified emission monitoring had hardly been thought of, e.g. due to the invention of the first photometer which operated according to the NDIR method [1]. Before emission monitoring, continuous gas analysis was already being carried out in various areas of industry such as the chemical industry, in power stations, steel manufacture or in mining.

The following general comments are based on the developments in Germany but they may well be similarly relevant for other European countries.