Application Research Of RBI Technology On Heavy Oil Catalytic Cracking System

RBI (Risk-Based Inspection) is an arising technology in the world in recent years, which aims at, within an acceptable risk range, optimization of equipment test’s frequency and efficiency, maintenance of equipments’ safety margin, and reduction in daily check and maintenance costs. This thesis discusses RBI analysis methods, analysis procedures and risk estimation based on the progress history of the device management. On this basis, a overall risk assessment is made on the system of heavy oil catalytic cracking (FCC) in Lanzhou Petrochemical Company, by adopting RB-eye@(RBI analysis software) developed by BV company in France. The risk matrix is developed. According to the results, the reasons which cause risks are analyzed for the high risk equipment in the heavy oil catalytic cracking system, from point of view of design and manufacture, corrosion mechanism and process operation. The rationality and reliability of the results are argued.The FCC is divided into five sections in this thesis, which are reaction®eneration section, fractional distillation section, absorption&stabilization section, merox section, and gas recovery section. RBI analysis is put on223static equipment of FCC. It concludes that there are136high and middle-high risk equipments, accounting for53.2%of the equipment,In this thesis, the inspection plan in the confonnity is developed with the national conditions for the high risk equipments and piping. Controlling risk through on-line inspection and improving management level are proposed as remedial measures for reducing risk. Solutions to problems about the regenerator shell, such as Nitrates SCC problem, Hydrogen sculphide corrosion problem, carbonate stress corrosion problem and caustic embrittlement problem, are provided.The reasons why the ratio of equipment with middle or high risk in China is higher when using RBI is analyzed. It is mainly manifested as follows. The first one is that some of the static equipment and pipelines with design manufacturing defects may result in excessive deficit. The second one is the test is lack of effectiveness and relevance, because of the failure to give full consideration to the damage mechanism and damage equipment. Thirdly, some equipment and piping are in the extended duty status, and lack of effective inspection. The last one is that the management level also lag to other foreign countries.The improvement ideas on the problems facing the application of RBI in China are suggested. Chinese laws and safety technical specification are consistent with RBI. Risk-based inspection activities must be carried out in the permission of laws and regulations, and within the supervision of the government. RBI can make the inspection cycle of pressure equipment more reasonable, and not just by extending it. So in order to develop the RBI technology, regulations and safety technical specification should documented relevant provisions of the RBI. Although the risk analysis method is a general principle, API580and API581documents are limited in the scope of application, and sometimes need to add the corresponding basic data. The realities of Chinese pressure equipment must be considered when RBI technology is used. On-line detection method should be allowed in stead of stop when the test. Application of the RBI technology can not pursuit of short-term direct economic benefits, but should be based on the nature of the safety and long-term operation at lower costs.