Heavy Oil Catalytic Cracking System Security Analysis And Key Risk Assessment Study

With the development of economy, the demands for petrochemical are increasing rapidly. As the key tache of the petrochemical industrial chain, oil refining industry developed rapidly. Heavy oil FCC Unit is the core equipment for oil refining factories. Along with continually expanding of the production scale of heavy oil FCCU, how to keep it safely, smoothly and long-term operating becomes very important. Safety system analysis and risk inspection in its process is an important measure to discover the latent risk factors, to prevent accidents, and to ensure the process running safely and steadily. One of domestic refineries' FCCU was selected to be safety analyzed and risk evaluated in the thesis. The main contents in this dissertation were described as follow:1. The production system safety of the domestic refineries' FCCU was systematically analyzed backward with the method of FMEA. The main fault modes and effects were got. The analysis result indicated that a majority of risks of the FCCU exits in the Reactor-Regenerator System.2. The production system safety of the domestic refineries' FCCU was systematically analyzed forward with the method of FTA in order to get the main causations of risks. Because the bottom event is the indicate causation for risks but not the indicate objects of risks in the FTA method. A system dividing method based on the character matrix was put forward. The production system of the FCCU was divided into processing units and equipment units with this method. Then a new risk analysis method based on system-dividing and FTA was put forward. Its main principle is that the structure-wieght of FTA should maple to the structure-wieght of the processing unit or equipment unit. Then the risks of the production system of the FCCU were analyzed with this method.3. The key processing risks of the production system of this FCCU were analyzed. A risk evaluation method based on the soft-sensing technique was put forward because the proceeding parameters were always measured difficultly. And the models of risk evaluation were founded. 4. The risks of heavy oil FCCU include its failure probability and failure effects. So the key equipments risks of the production system of this FCCU were analyzed based on RBI risk evaluation method. Because the risk evaluating on the heavy oil FCCU includes multi-dimensional and multi-level factors and a lot of uncertainties, so the interval number fuzzy integrated evaluation method was put forward. Then the key equipments risks of the production system of this FCCU were analyzed based on this method.