Identification And Control Measures For Critical Risk In Residue Fluid Catalytic Cracking Unit

With the continuous development of national economy and science and technology,the petrochemical industry plays a more and more important role in the development of the country.However,in recent years,accidents frequently occur in the petrochemical industry,which not only causes huge property losses to the country and people,but also destroys one happy family after another.It has become a hot topic in today’s world on how to effectively identify the harmful factors in the production process of oil-refining enterprises and take positive & effective measures to control them.Catalytic cracking is an important step for heavy oil processing in China.Because the process of catalytic cracking is complicated,raw material and product are characterized by flammable,explosive and high temperature,which is extremely prone to result in malignant accident such as fire explosion,consequently it is of great significance in safe & stable operation of heavy oil catalytic plant to conduct safety assessment with scientific assessment method.This paper carries out a variety of research works based on identification and control of critical safety risk in catalytic cracking plant,mainly including the following aspects.Firstly,hazardous chemicals generated from production and storage are analyzed on an item-by-item basis,to determine the characteristics regarding flammability,explosion and toxicity.According to the physical & chemical properties with specific reference to <fire prevention code of petrochemical enterprise design>,fire hazard is categorized while bringing forward fire-extinguishing measures.On the basis of the physical & chemical property of toxic & harmful substances,symptoms of toxic and harmful substances after poisoning as well as the first-aid measures are sorted out.After analysis for the causes of the previously-occurred accident,in consideration with the emergency management method currently-adopted by the plant,which provides a basis for the identification of the critical risk factors of the plant.Secondly,the overall safety assessment is carried out for the plant from the following 3aspects such as hazard identification and risk assessment regarding the process technology,risk identification and control about operation and job activities,and risk identification and control for equipment and facility,finding out the main risk factors existing in the plant.Through the analysis for the cause of major risk factors,the primary reasons at present behind limitation of safe & stable production of plant are sorted out.It can be specifically summarized as personnel operation,equipment/facility failure and safety leadership.The cause analysis is carried out based on the three-aspect above,while the corresponding control measures are put forward.Thirdly,the level of fire and explosion risk for the plant is evaluated with F&EI method by Dow Chemical.In view of actual operating condition of the plant,analysis for the type of the explosion to the liquefied gas storage tank under leakage is carried out.FTA is employed to do the probability calculation for all kinds of explosions,drawing the conclusion that the probability of leak-related fire & explosion is the maximum.The corresponding prevention measures are put forward for the fire and explosion of liquefied gas storage tank.Finally,in combination with the case about the leakage of liquefied gas storage tank,PHAST software was used to simulate the consequences of combustible gas diffusion after leakage.Based on the analysis of the thermal radiation after the jet fire and the shock wave after the explosion,the safe distance of the plant under different weather conditions is obtained,which provides data reference for emergency response in the future.In view of the current office area and the installation of a short distance and the office Windows towards the installation of the area and other problems put forward rectification recommendations.The corrective recommendations are come up with,in regard to the short distance between office area and plant area as well as the orientation of windows for the office building towards plant area.