~ Pergamon Radiat. Phys. Chem. Vol.45, No. 6, pp. 1049-1055,1995 Copyright © 1995Elsevier Science Ltd 0969-806X(94)00165-0 Printed in Great Britain.All rights reserved 0969-806X/95 $9.50 + 0.00 COMPUTER MONITORING AND CONTROL SYSTEM (CMCS) FOR ELECTRON BEAM FLUE GAS TREATMENT M. SOWIIqSKI, 1 T. PLAWSKI, l M. OSOWIECKI,2 M. KOBUS, 2 M. 7,AK, 2 A. CHMIELEWSKP and J. LICKI 4 ~Soltan Institute for Nuclear Studies, 05-400 Otwock-Swierk, Poland, 2polon System, Warszawa, Poland, 3Institute of Nuclear Chemistry and Technology, ul. Dorodna 16, 03-195 Warszawa, Poland and 4Institute of Atomic Energy, 05-400 Otwock-~wierk, Poland Abstract--The computer monitoring and control system (VME based) with various facilitiesare described. The solution of preparing sampling probes and automatic calibration system is also presented. 1. INTRODUCTION The development of electron beam flue gas treatment technology put still growing demands on associated computer systems for data acquisition and control [Licki et aL (1992) and Szlachciak et aL (1992)]. The early systems based on mechanical and man- ual-control, having high degree of complexity and resultant low legibility, are replaced by digital sys- tems. Similarly, in the class of computer systems very large changes are also seen. The popular systems based on PC-class computers equipped with ADC & DAC cards and digital IN/OUT, appeared to be unrealiable mainly due to excessive centralisation of measurements and control processes. Dedicated in- dustrial controllers, excellent in the simple and cheap installation, here where there is a need of continuous development and changes, are not flexible enough. It appears that the most effective design is that of Modular Computer Systems based on international standards, e.g. VME and VXI. It was decided to use such a solution in the design and construction of the system described in this paper. The additional arguments on the favour of the open modular systems are following: (1) There is continuous, fast influx of new, mod- ernised execution units like regulation valves, pressure stabilisers, pump and so on; this new generation of execution units have standard con- trol and measurement signals; (2) There is also an influx of a new generation of gas analysers continuously miniaturised and industri- ally prepared to interface the computer systems. Of course this phenomenon is to some extent symmetric. The installation in which the modern computer system is to be used must fulfil a series of conditions concerning the possibility of control of execution units and analytic devices, as well as the accessibility to the parameters to be measured. In this report we wish to describe the system the first part of which is already in operation at EPS KAWECZYN pilot plant. The next components of the system are in realisation. Additionally, we de- scribe parts of flue-gas scrubbing installation adapted to the co-operation which modern systems of moni- toring and control. 2. METHODS OF FLUE GAS PREPARATION FORANALYSIS Application of modern flue gas analysers requires the flue gas from different points of installation to be properly prepared. Usually these points are distant from each other and are located in not easily accessi- ble places. The transport lines become long (high cost particularly in the heated lines). This creates the problem of settling of impurities in the lines. There is a question of the number of analysers to be used. To keep the cost of total system low one tries to use a single analyser for a large number of measured points. This, however, complicates the sys- tem of transport and switching. Continuous monitoring of emission of such gases as SO2, NOx, CO 2 or NH 3 is technically much more complicated than monitoring of their emission. In our case, flue gas emitted from the coal-fired boiler consisted of: CO2 (9-12%), 02 (6-9%), H20 (4-6%), SO2 (0.054).5%), NOx (0.024).2%) and nitrogen (after electron irradiation appear NH3, N 20 and O3). In 1992-93 a few methods and systems for prep- aration of flue gas for analysis and monitoring have been developed. Figure 1 shows the flow diagram of one of those systems. 1049