Investigation On The Ultimate Pressure Of Ultrahigh Pressure Tubular Reactor

The reaction tubes are widely used as reaction vessels, separation vessels or heatexchangers in the high pressure vessel. Usually, the working pressure is higher than100MPa,even up to several thousand MPa, the consequences will be unimaginable in case of a leakageaccident at such high working pressure. Therefore, studying the ultimate pressure andanalyzing the stress distribution, ultimate bearing capacity of the reactor vessel is extremelyimportant.In this article, experiment and nonlinear finite element analysis method was used tostudy the ultimate pressure of thick wall straight tube and bending tube （R/D=13.8） underthe internal pressure situations, the following main conclusions are gotten:（1）Comparing the result of the nonlinear finite element simulation of the reaction tubeswith experimental results, the relative error did not exceed±4.5%, whether used the zerocurvature criterion or the slope of twice elastic criterion to determine the ultimate pressure.（2）The relative error of the bend pipe’s ultimate pressure did not exceed±1.9%comparing with the straight pipe, whether used the zero curvature criterion or the slope oftwice elastic criterion to determine the ultimate pressure.（3）For the bend pipe with R/D≥5, the relative error of the ultimate pressuredetermined with zero curvature criterion and the straight pipe’s ultimate pressure was lessthan0.65%, therefore, the calculation of the ultimate pressure can be regarded as a straightpipe.（4）For the bend pipe made of30CrNiMo8, which has served for20years and thediameter ratio K between2.0³.0and R/D≥5, according to the zero curvature criterion,ultimate pressure can be calculated using the following formula: P₀=-85.9772+451.5727kBy comparing the theoretical ultimate pressure and the test results of the two differentforms of reaction tube——the straight pipe and bend pipe, informative data can be providedfor the safety assessment of the in-service reaction tubes, which is of great practical projectsignificance and academic research value.