Scientists from Peter the Great St. Petersburg Polytechnic University (SPbPU, PolytechScientific )’s and Technological Complex “New Technologies and Materials” of the Competence Center of the NTI “New Production Technologies” investigate how hydrogen affects the structure and properties of pipe steels. The findings will demonstrate that the existing gas transmission system is capable of carrying energy hydrogen over a network of pipes, as well as aid in determining the hydrogen infrastructure’s safety.
It’s not straightforward to switch from old hydrocarbons to hydrogen. Difficulties are mostly due to the materials utilized, which include steels that are not intended to cope with compressed hydrogen. They can, however, be utilized to enhance the volume of pure gaseous hydrogen and methane-hydrogen mixes produced, stored, and transported. The research of St. Petersburg specialists will allow them to assess the hydrogen permeability of steels as well as the influence of a hydrogen-containing gas mixture on the characteristics of the metal used in gas transmission pipes and equipment.
Hydrogen is delivered in a variety of forms (cylinders, tankers, pipes, etc.) and states (gas, liquefied gas, mixed with methane, in the form of ammonia, etc.). Pipeline transport is the most cost-effective technique to transfer big, consistent volumes. Simultaneously, although previously hydrogen was carried via short-distance pipes with small diameters and varied pressures, the aim today is to analyze the feasibility of employing major pipelines with bigger diameters and working pressure pipes.
“One of the key issues with transporting hydrogen through pipelines is the embrittlement impact on the pipe material, the amount of which is currently unknown.” Research techniques, assessment criteria, and requirements for materials in contact with pure gaseous hydrogen under pressure are not controlled in the United States. The outcome of our research will be a determination of existing pipe steels’ resistance to hydrogen embrittlement at a certain pressure or hydrogen concentration in a methane-hydrogen combination. Furthermore, the development of research methodology will allow for the formulation of requirements and criteria for assessing the effect of gaseous hydrogen on the structure and properties of pipe steels,” said Nikita Shaposhnikov, Executive Director of the SPbPU NTI Center’s NTC “New Technologies and Materials.”
Hydrogen atoms are able to permeate steel due to their tiny mass and size, as well as their great diffusive mobility. Steel’s ductility can be reduced by hydrogen contact, resulting in structural degeneration.
The STC “New Technologies and Materials” has developed a Devanathan-Stachursky electrochemical cell for determining hydrogen permeability, as well as a stationary autoclave for preliminary hydrogenation and an autoclave with a built-in loading system (using a universal testing machine), all of which recreate the conditions for transporting a hydrogen-containing gas mixture through pipes and allow tests on the resistance of materials to hydrogen embrittlement, such as steel.
An autoclave is a pressure vessel, as you may recall. It is important to produce a gaseous medium in a specific volume and at a specific pressure (for example, the working pressure of gas transportation through a pipeline). This is accomplished by squeezing hydrogen gas. The test sample is put in a volume before being subjected to the medium and pressure, simulating the effect of the transported medium under pressure on the pipe wall material during transit. Tensile tests are used to determine the degree of hydrogen embrittlement and offer information about the key mechanical features.
In Russia, only SPbPU possesses such a set of equipment, which allows materials to be examined in both normal and pressurized hydrogen environments. The research is being conducted by the NTI Center of SPbPU as part of the Russian Ministry of Education and Science’s nationwide initiative “Science and Universities.”
