In the context of the shipping industry emission reduction target set by the International Maritime Organization and based on the current situation of carbon reduction in the shipping industry, this paper introduces the development history and emission reduction advantages of hydrogen powered ships, analyzes the hydrogen storage methods of hydrogen powered ships at home and abroad and the safety risks of hydrogen energy onboard, and compares the technical advantages and onboard feasibility of various Marine hydrogen storage methods. It is concluded that the hydrogen production technology of shipboard methanol steam reforming is of great significance to solve the hydrogen safety problem of hydrogen?powered ships. At last, the problems faced in developing hydrogen?powered ships with shipboard hydrogen production units are put forward.

The finite element model of the bolt flange washer was established, and the fastening experiment of the DN500 bolt flange connection system was carried out to verify the rationality of the finite element model. By controlling the width of the nut washer and the medium pressure of the pipeline, the effect of adding the nut washer on the stress distribution on the washer and bolt was compared and analyzed. It was found that adding a reasonable sized nut washer can not only increase the contact area between the nut and the flange surface and increase the compressive stress on the gasket, but also in the case of high bolt pre?tightening load and medium pressure. Prevent the bending deformation of the bolts and the pressure failure of the washers, increase the service life of the bolts, and improve the overall sealing performance of the bolt flange connection system.

In order to study the sealing performance of bolted flange connection system under high temperature condition, the thermal?structural coupling analysis of bolted flange connection system under 400.00 ℃ was carried out by Ansys?Workbench. The results show that the temperature decreases gradually from the inside of the flange wall to the outside, the maximum stress appears on the contact surface between the nut and flange, and the maximum strain appears on the gasket. Evaluated the sealing performance of gaskets at room temperature and 400.00 ℃; at the same time, aiming at the easy sealing failure of gaskets in the connection system under high temperature, established gasket strength failure of bayesian networks, based on a series of methods such as expert evaluation to calculate the prior probability, used Bayesian network reverse reasoning to calculate the posterior probability of the root node and sort them to find out the main factors leading to the invalid gasket, so as to enhance the reliability in the process of using gasket.