Nagynyomású hidrogénatmoszférás kemence gyártása szénacélok elridegedésének vizsgálatához
Authors: Varbai Balázs , Katula Levente , Dobránszky János , Fodor Olivér 
Published: May 2024

Összefoglalás.

A hidrogén tárolása iránti igény egyre növekszik, melynek oka az, hogy a hidrogén
mint alternatív energiahordozó jelentős szerepet játszik a
szén-dioxidkibocsátás-csökkentési törekvésekben. Azonban, az elridegedési
folyamatok körében a hidrogén által előidézett károsodások jelentik a
legkomolyabb problémát az acélokra nézve. Kutatómunkánk során egy nagynyomású
hidrogénatmoszférás hőkezelésre alkalmas autoklávot terveztünk, majd
gyártottunk. Az autoklávban P355 NH minőségű alapanyagból kimunkált szabványos
Charpy-féle ütőpróbatesteket hőkezeltünk 150 °C-on, 40 bar túlnyomáson, 200 órán
keresztül, tiszta hidrogén atmoszférában. A vizsgálatok eredményei alapján
megállapítottuk, hogy a jelentős mértékű elridegedés a hidrogénezési folyamat
után sem történt.

Summary.

The demand for hydrogen storage is growing. The primary reason for this is that
hydrogen as an alternative energy carrier is playing a significant role in
carbon reduction efforts as a fuel for road and maritime transport. In addition,
hydrogen can be seen as a long-term flexible energy storage option. Hydrogen as
an energy carrier is expected to play a significant role in residential and
industrial use in the future. A first step in this development is the mixing of
hydrogen with natural gas in small quantities. Increasing the share of hydrogen
would not only reduce CO2 emissions, but would also facilitate the
development of different hydrogen production methods and thus reduce production
costs. The upper safety limit for hydrogen blending with natural gas is set by
the national specification of the natural gas supply, possible material quality
restrictions and the tolerance of the most sensitive equipment in the network.
For this reason, the maximum allowable hydrogen content in natural gas is
generally limited to 2,5%.

However, among the embrittlement processes, hydrogen-induced damage is the most
serious problem for both non-alloy and low-alloy steels. Atomic hydrogen
diffuses in steel at high rates. The diffusion rate is orders of magnitude
higher than that of other elements; this is due to the small atomic diameter of
hydrogen.

To investigate the degradation of different carbon steels in a high-pressure
hydrogen atmosphere, a hydrogenation furnace was designed and fabricated at the
Department of Materials Science and Engineering at BME. The hydrogenation
furnace is the main part of a complex mechanical engineering system, for the
operation of which the mechanical, heating, electrical supply, control and gas
handling components are indispensable. The entire design process of the furnace
was led by József Blücher, Professor Emeritus at BME, with the help of the
engineers and technicians working on the project. Standard Charpy impact test
specimens were machined from P355 NH grade material to test the embrittlement of
carbon steels. The hydrogenation temperature was 150 °C, the internal
overpressure in the chamber was 40 bar, the hydrogenation time was 200 hours and
the atmosphere was hydrogen gas of purity 5.0. The impact test was carried out
at -20, 0 and +20 °C.

Based on the results of the tests, it can be concluded that there was no
significant degree of degradation both before hydrogenation and after prolonged
exposure to hydrogen. It can be concluded that the tube material used as a
sample is suitable for operation in a hydrogen medium. Based on the analysis of
the burst areas and impact values of the impact test specimens, it was concluded
that hydrogen did not cause any observable damage to the test material.