Design and Manufacture of Pressure-Bearing Equipment Based on Risk and Life Analysis

Since the turn of the 21^st century, the technical means for engineering risk analysis for safety assurance of in-service equipment such as risk-based inspection (RBI), reliability-centered maintenance (RCM) and safety integrity level (SIL) etc. have been extensively applied in Chinese petrochemical enterprises, and good effect has been achieved. However, it is found that most of the causes for accidents or failures are due to unreasonable design and manufacture, or deviation of design and manufacture requirements from the requirements for service environment. The existing design standards and software are short of database support of failure mechanisms and failure modes, etc. in the service process of pressure-bearing equipment without fully taking into account various kinds of risk factors in the dynamic service environment in the full life process of pressure vessels, therefore, it is unable to determine the service life of pressure-bearing equipment in advance. In this paper, by taking the design and manufacture of hydrogenating reactor and large ethylene spherical storage tank as examples, suggestions are made about the risk and life analysis based design and manufacture to be carried out in China for important pressure-bearing equipment, that is, within the design life (intended service life) of pressure-bearing equipment, considerations should be given to various kinds of failure modes possibly arising under the dynamic service conditions in the full-life process and the effect of risks due to damage mechanism on equipment safety and life so as to control and reduce the risk of pressure-bearing equipment in the full-life process at the early stage of design and manufacture through reasonable material selection, improvement of structural design and optimization of manufacture process, etc. and make the equipment serve to the expected design life safely in combination with other process guarantee measures. Finally, the critical technical bottlenecks waiting for solution for the development of risk and life based design and manufacture in China are described in combination with the latest news about the revision of Chinese technical codes and standards.