IMPROVEMENT OF AUTOMATIC CONTROL SYSTEMS AND SAFETY INSTRUMENTED TUBE FURNACES ON THE BASIS OF MONITORING OF THE COKING PROCESS PARAMETERS

Abstract

Tubular heating furnaces are an important element of modern oil and gas complex, they are used for high temperature heating and reactions of liquid and gaseous oil products. At the same time, tubular heating furnaces are one of the most hazardous production facilities. The most common method of ensuring industrial and fire safety tubular heating furnaces is the use of emergency warning systems (EWS) and emergency automatic protection (EAP). Causes of accidents and their consequences in tubular heating furnaces are: - depressurization of a tubular coil – is the predecessor of the fire of the furnace; - the extinction of the burner – which causes an explosion in a tube furnace; - depressurization of equipment outside the furnace leads to an explosion the outside of the tube furnace. In this article, we have considered in detail one of the emergency situations in tubular furnaces, namely a fire caused by the burnout of the tubular coil. This situation was chosen because it is most often occur in process plants with tubular furnaces. It potentially improve terms of improving systems of automatic control and EAP. Burnout of the tubular coil is very often associated with its coking. At the moment, the introduction of the contours of the EAP of the stop function of the furnace due to coking of the coil is not implemented, only the triggering of EWS. In this paper we propose an improvement of automatic control systems, EAP and EWS tubular furnace by monitoring parameter of a coking – speed coking. The rate of coking is proposed to calculate using the virtual quality analyzers using the parameters of the coking process: temperature, flow, pressure, product density, and other parameters. The obtained value of the coking rate will be the average value due to the fact that it is not constant along the length of the tubular coil.