Development And Implementation Of Cracking Severity Control System For Ethylene Plant Of Qilu Company

Cracking severity of ethylene cracking furnace is an important index for cracking reaction, and in practical application it must be controlled in a suitable range to acquire a given cracking product yield (mainly ethylene and propylene yield) Cracking severity dynamics is a complicated nonlinear process and is affected by quite a few factors, which can be described by few mature mechanism models till now. Consequently, the cracking severity control strategy is a key research topic in the research of the advanced control technology of ethylene cracking furnace.In this paper, based on the background of the Cracking Severity Control transformation of the olefin plant of Qilu Branch of Sinopec, according to the plant BA-101～BA-104, BA-112～BA-117,10 sets of liquid phase raw material cracking furnaces implementation of cracking severity control. Intelligent cracking depth neural network prediction model of Smith Predictor Control scheme is introduced into cracking severity control based on the application of temperature and carrying capacity advanced process control system, the model can predict the direction of change of the cracking severity, according to the changes of the properties of the raw materials and the changes of the operating conditions of the cracking furnace timely and accurately and to implement the corresponding control. At the same time, this paper puts forward a method based on DMC predictive control algorithm to realize the cracking severity control. This paper elaborates the construction and application of the analysis system of cracking gas chromatogram analyzer. The fault diagnosis programs are designed based upon the certain familiar faults. Some practical applications of the cracking severity control technique in several crackers of QiLu olefin plant show that the control of the cracking severity of ethylene cracker can be suitable the change of the feed composition with good reliability and stability.