Development of a Web-Based RBI Program for LNG Plant Considering Cryogenic Environment

Recently, Risk-Based Inspection (RBI) evaluation technique based on API 581 has become a preferred approach to determine economic feasibility and safety to plants. However, there are limitations of applying API 581 to Liquefied Natural Gas (LNG) plant because its liquefaction process is operated in cryogenic temperature under −162 °C. It could affect the risk of main components in liquefaction process, but API code considered the temperature range of about −40∼149 °C to evaluate the brittle fracture damage factor. The objectives of this paper are to develop a RBI program based on a web-based reality environment to resolve the above issue and to evaluate the risk of equipment in LNG plant. To achieve these, Minimum Design Metal Temperature (MBDT) region of impact test exemption curves were extended to about −196 °C. Risk evaluation results considering cryogenic temperature and applicability of the proposed RBI program are fully discussed in the paper. The proposed RBI program will be useful to evaluate risk of the major components in cryogenic environment.

The Morphology Analysis of Axial Creep-Feed Grinding about Engineering Ceramics with a Small Grinding Wheel

The plastic deformation and brittle fracture damage remained within a certain depth of the abrasive surface of ceramic materials during axial creep feed grinding process, which included much information about damage mechanism and removal mechanism of ceramic materials. The surface morphology analysis showed that the brittle fracture was the main removal mode of grinding surface in addition to some micro-cracks in the affected layer, and cracks were not found in the matrix. Compared with general grinding, only the surface deterioration layer is thicker than general grinding surface, and there is no obvious damage to the workpiece