Összefoglalás.
Az energiaigény és a megújuló energiaforrásokból származó kínálat között fennálló
szezonális eltérés áthidalható a hidrogéngáz bevezetésével az energiaellátásba.
A nagy léptékű energiatárolás hidrogén formájában a felszín alatti térben
lehetséges. Azonban a kőzet pórusterében az injektált hidrogén hatására
végbemenő reakciók nemcsak a kitermelendő hidrogén mennyiségét és minőségét
csökkentik, de a kőzet hosszabb távú állékonyságát is ronthatják. A
Kárpát-Pannon régióban jelentős mennyiségben találhatók porózus kőzetek, amelyek
hidrogéntárolásra is alkalmasak lehetnek. Ugyanakkor, ezek a kőzetek változatos
ásványos összetételük miatt reakcióba léphetnek a hidrogénnel. Vizsgálatunk
célja, hogy megismerjük a kőzetalkotó ásványok viselkedését pórusvíz és hidrogén
jelenlétében, amely elengedhetetlen a rezervoár tárolási potenciáljának
felméréséhez.
Summary.
One of the key substances in the modern-day energy transition is hydrogen, which
can be utilized as an energy storage chemical substance. To store hydrogen on
the scales required for global hydrogen economy, porous geological formations
should be considered. However, geochemical challenges associated with hydrogen
storage in sedimentary formations are still not well understood. Mineral
dissolution and precipitation, as a result of hydrogen injection into the rocks
not only can decrease the quality and the quantity of the stored hydrogen but
may have an impact on the rock integrity as well. The Carpathian Pannonian
region is rich in porous rocks, which could serve as hydrogen storage sites.
However, many of them show various mineralogical compositions, which could
behave differently under high hydrogen partial pressure. The main objective of
our study is to predict geochemical reactions among rock-forming minerals, pore
water and hydrogen. For this purpose, we apply analytical techniques and
geochemical modeling.
The subject of this research is the Late Miocene Szolnok Sandstone Formation
located in the Pannonian Basin, Carpathian-Pannonian Region. In the future this
Formation can play a significant role in hydrogen storage, due to its favorable
reservoir geological and petrophysical characteristics.
X-ray diffraction analyses were carried out, polished and thin sections were
prepared for petrographic and geochemical analyses. The collected data were used
in the PHREEQC modeling environment. In the first stage, equilibrium batch
models were made to assess the potential long-term impacts of hydrogen on the
reservoir rock and the effect of the geological environment. The modeling
results of the project showed that hydrogen almost does not react with silicates
(e.g., quartz). Possible hydrogen loss can occur due to redox reactions. Pyrite
(FeS2) can react with hydrogen producing hydrogen sulfide
(H2S) and since petrography has revealed that the studied
sandstones have pyrite as accessory mineral.