MODERN GAS FLOW MONITORING PRACTICES: A REVIEW OF ULSTR-SONIC SYSTEMS WITHIN CEMS APPLICATIONS

1. Introduction
Originally TA LUFT and later USA EPA regulations required emissions reporting on a daily mass basis. This stimulated the development of continuous flow monitors to allow accurate determination of mass emissions.

At present in the UK, annual tonnages for particulates, SO2 and NOx are calculated using a factor for m³ flue gas per kg fuel burned. It is envisaged that future EC emission regulations will require monitoring of actual flue gas volumes discharged to atmosphere.

A new continuous flow standard, developed by ISO, has recently been adopted as a British Standard (BS ISO 14164:1999).The introduction of the UK MCERT scheme demonstrates the intention of the UK Environment Agency to enforce emissions regulations.

In this document, several technologies for gas flow measurement are introduced with the emphasis being on ultrasonic flow measurement. Some application examples are introduced by means of the SICK AG´s Flowsic instrument range..

The FLOWSIC instrument described in this paper complies with the new flow standard and is presently awaiting MCERT testing.