Safety Assessment For Heat-wall Hydrogenation Refining Reactor

With the development of petrochemical industries and the requirement of environment protections, hydrocracking emerged. Low-carbon, low-alloy steels are often used in petrochemical industries and refineries. These steels mainly contain Cr, Mo or V as significant alloying elements. It is Introduced that the main types of corrosion in hydrocracking unit are high temperature hydrogen damage, high temperature hydrogen and sulfureted hydrogen corrosion, temper brittleness of chrome-molybdenum steel, corrosion of polythionic acid. The Cr-Mo pressure vessel steels have a potential for hydrogen and temper embrittlement that leads to toughness degradation and decrease of the critical flaw size for brittle fracture. With respect to this fact, there is a growing importance being attached to the assessment of the integrity of such structures that work at high pressure and elevated temperatures. In this investigation the effect of high temperature and high pressure hydrogen on a vessel, made of21/4Cr-1Mo and3Cr-1Mo-1/4V low-alloy steel is studied. These predicted values were compared with Kic values obtained from Rolfe-Barsom equations based on Charpy V-Notch (CVN) impact test results. This paper presents the results of the research aimed at developing fracture toughness correlations. Results from two methods of measuring the fracture toughness are presented and discussed: Charpy V-Notch testing and small punch testing. Samples were taken at two locations: de-embrittling and embrittling. As to hydrogrn embrittlement, Threshold temperature is calculated. By using the fracture mechanics and safety analysis curve, the safety of major equipment is evaluated. Safety measures taken in the design of hydrocracking unit is put forward. Safety measure will be offered to ensure safety during operation, production and shutdown.