Faculty of Mining, Geology and Petroleum Engineering Repository
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Numerička analiza učinkovitosti bušotinskoga izmjenjivača topline u plitkim vodonosnicima šljunka i tlu u kojemu dominira glina
No full textThe performance of geothermal heat extraction in shallow aquifers depends on both Borehole Heat Exchanger (BHE) and soil or aquifer properties. In this work, an analysis of the thermal yield of a shallow geothermal reservoir was made numerically with the finite element method used to simulate heat and mass transfer in the three-dimensional reservoir. The main parameters for analysis which have been considered are the geometry and physical parameters of the BHE and grout, as well as aquifer matrix and groundwater fluid. Physical parameters are thermal conductivity, flow conductivity, expansion coefficient, porosity, volumetric heat capacity, anisotropy and dispersivity. The numerical tests have been performed in single BHE line source configuration representing numerically modelled thermal response test for the estimation of sustainable heat extraction. The domain size was a 100x100 meter rectangle with a depth of 200 meters. Three main lithological configurations have been modelled: gravel aquifer with low and high convection of groundwater fluid, as well as a shallow geothermal reservoir dominated by clay material without convection. For selected cases, the analysis for temporal and spatial discretization was also made. Three-dimensional transient modelling was made in FEFLOW® software with pre- and post-processing done in user-defined Python scripts. The results show the most influential parameters to be considered when setting up the real case simulation of geothermal heating and cooling, as well as optimal temporal and spatial discretization set-up with respect to expected thermal gradients in the reservoir.Učinkovitost korištenja geotermalne topline u plitkim vodonosnicima ovisi o bušotinskome izmjenjivaču topline (BHE) i svojstvima tla ili vodonosnika. U ovome radu numerički je napravljena analiza osjetljivosti toplinskoga prinosa plitkoga geotermalnog ležišta metodom konačnih elemenata korištenom za simulaciju prijenosa topline i mase u trodimenzionalnome ležištu. Glavni parametri za analizu osjetljivosti koji su uzeti u obzir jesu geometrija i fizički parametri BHE-a i cementne obloge te matrice vodonosnika i podzemne vode. Fizički su parametri toplinska vodljivost, vodljivost protoka, koeficijent ekspanzije, poroznost, volumetrijski toplinski kapacitet, anizotropija i disperzivnost. Numerički testovi provedeni su u konfiguraciji jednoga bušotinskog izmjenjivača topline koji predstavlja numerički modelirani test toplinskoga odziva za procjenu održivoga korištenja topline. Domena je bila pravokutnoga oblika 100 x 100 metara s dubinom od 200 metara. Za svaku analizu osjetljivosti modelirane su tri glavne konfiguracije: šljunčani vodonosnik s niskom i visokom konvekcijom podzemne vode te ležište u kojemu dominira glinoviti materijal bez konvekcije. Za odabrane slučajeve također je napravljena analiza osjetljivosti na vremensku i prostornu diskretizaciju. Trodimenzionalno modeliranje napravljeno je u softveru FEFLOW® uz prethodnu i naknadnu obradu u korisnički definiranim skriptama za Python. Rezultati pokazuju najutjecajnije parametre koje treba uzeti u obzir pri postavljanju stvarne simulacije slučaja grijanja i hlađenja geotermalnim izvorom, kao i optimalnu postavku vremenske i prostorne diskretizacije s obzirom na očekivane toplinske gradijente u ležištu
Soil formation and environmental reconstruction of a loess-paleosol sequence in Zmajevac, Croatia
No full textLoess-paleosol sequences are widely recognized in the Pannonian region from a sedimentological perspective; however, fewer studies are focusing on the soil formation processes within these paleosols. We present a detailed pedological study of one of the sequences in Zmajevac, aiming to complete the paleoenvironmental information related to these paleosols, particularly to decipher the nature and environmental conditions that formed the thick, slightly developed (cumulus) Bw horizons on top of the three paleosols in the selected sequence. Chemical, physical, mineralogical, and micromorphological analyses, as well as 14C dating of shells, were performed on samples from the three paleosols and the recent soil of the Zmajevac sequence. The results suggest that a discontinuous but rather rapid supply of aeolian and partly alluvial materials led to weak soil formation in all paleosols, limited to calcium carbonate mobilization. The sedimentary accretion processes and milder climatic conditions account for the lack of significant rubefaction and the absence of clay illuviation. The most recent (ZN REC) soil is a paleoclimatological archive of the Bølling–Allerød interstadial period. Each older paleosol section represents three sedimentological and pedological events from MIS 3 (ZN 1), MIS 4 interglacial (ZN 2) and MIS 5e (ZN 3). In general, the younger the age of the horizons within each succession, the lower the level of development. These top horizons of investigated sequences are Bw (cumulus) horizons. Thus, this study enhances our understanding of paleoenvironmental conditions in the Pannonian region
Mammal-bearing Pleistocene deposits, Vranić, southwestern Pannonian Basin System
No full textVranić site is a sand quarry that is located on the southern foothills of Papuk Mountain. Frombottom to top of the succession, three sedimentary units have been recognized as: Unit 1 containing massivesand with scattered gravel-sized clasts, marl cobbles and boulders, and abundant marine mammal and fish fossils; Unit 2 consisting of sand intercalated with silt, clay and gravel, which may be horizontally bedded; and Unit 3, which is an erosionally-based lenticular matrix to clast-supported structureless gravel. The basal part of Unit 1 shows numerous reworked skeletal remains of Miocene marine mammals. Cosmogenic radionuclides constrain the age of burial of Unit 1 to 895 ± 211 ka, while the source area of Unit 1 had a quick denudation. The massive sands deposited on the slopes of Papuk Mountain were vulnerable to erosion due to the absence of clay. Heavy rainfall or water from snow melting created flash floods that infiltrated the sands, thereby causing slope destabilization and deformation. This process led to slumps that were transformed into a sandy debris flow. This sediment was probably deposited during the interglacial marine isotope age (MIS) 21 period when the scarce vegetation and a warmer climate favored the melting of permafrost ice and consequently triggered slope movements during MIS 22. The reworked skeletal material sampled at the Vranic site comprises fossilized fish along with mammal bones and teeth. Thus, the Vranić site represents an important site for cetacean fossil remains and serves as an important data source for marine life in the Central Paratethys
New undergraduate and graduate studies in Applied geology and geological engineering in Croatia
No full textThe landscape of higher education is constantly evolving to meet the dynamic needs of various industries. In response, the University of Zagreb’s Faculty of Mining, Geology, and Petroleum Engineering has undertaken a crucial initiative to develop new undergraduate and graduate study programs in Applied Geology and Geological Engineering. This effort highlights the Faculty's commitment to both academic excellence and industry relevance. The new programs, set to commence in the academic year 2024/25, mark a significant advancement in geological education in Croatia. This presentation aims to illustrate the comprehensive approach taken in developing these programs, starting with the establishment of occupational standard and culminating in the implementation of curricula that align with both industry demands and academic expectations
Determination of the flooded area in the area of Karlovačka and Sisačko-moslavacka counties using multispectral satellite images Sentinel-2 in software language R : master's thesis
No full textKlasifikacija terena poplavljenog područja Karlovačke i Sisačko-moslavačke županije korištenjem multispektralnih satelitskih snimaka Sentinel-2 prije i poslije poplave. Satelitske snimke preuzete sa službene stranice geoportala Copernicus. Osim satelitskih snimaka, ulazni podaci su područje istraživanja i poligoni za treniranje izrađeni u programu ArcMap. Klasifikacija terena izvedena je strojnim učenjem korištenjem algoritama Random Forest, Support Vector Machine i Neural Network u programskom jeziku R.Classification of flood-affected areas in the Karlovac and Sisak-Moslavina counties using Sentinel-2 multispectral satellite images before and after the flood. The satellite images were downloaded from the official Copernicus geoportal website. In addition to the satellite images, the input data include the study area and training polygons created in ArcMap. The terrain classification was performed using machine learning algorithms, including Random Forest, Support Vector Machine, and Neural Network, in the R programming language
Strukturno-geološka analiza u mezozojskim i kenozojskim naslagama u okolnom području Tomislavgrada : završni rad
No full textU ovom završnom radu načinjena je strukturno-geološka analiza mezozojskih i kenozojskih naslaga na temelju prikupljenih terenskih podataka i već postojećih podataka u okolnom području Tomis lavgrada. U uvodnom dijelu rada opisan je geografski položaj istraživanog područja, kao i naslage koje se nalaze na površini istraživanog područja te je opisan dosadašnji pregled strukturno-tektonskih istraživanja. Potom su opisane metode rada te strukturna i mikropetrološka analiza temeljena na prikupljenim terenskim podacima. Terenskom analizom je utvrđeno da Šujički bazen, odnosno Šujička sinklinala predstavlja sinklinorij koji se sastoji od parazitskih bora višeg reda te da je rasjed koji razdvaja Kupreško-ljubušku tektonsku jedinicu od Slovinskocincarske tektonske jedinice strmo nagnut, odnosno okomit. Ovi podaci, zajedno s drugim podacima o orijentaciji slojeva su korišteni za reinterpretaciju strukturnih odnosa na području istraživanja, na temelju ko jeg je izgrađena strukturno-geološka karta i profil
Modeling of the bauxite deposit and underground rooms in the Studena vrila exploitation field with a proposal for the development of mining works : master's thesis
No full textU ovom diplomskom radu analizirana su ležišta boksita koja se nalaze u eksploatacijskom polju Studena Vrila, na granici općina Posušje i Tomislavgrada. Izrađeni su prostorni modeli (3D) terena, ležišta boksita i postojećih podzemnih prostorija u računalnom programu Open Roads Desinger (ORD). Prostorni modeli poslužili su za proračun rezervi boksita, pomoću metode računalnog modeliranja (MRM), te izradu prijedloga razvoja novih rudarskih radova.In this master thesis, the bauxite deposits located in the exploitation field of Studen Vrila, on the border of the municipalities of Posušje and Tomislavgrad, were analyzed. Spatial models (3D) of the terrain, bauxite deposits and existing underground rooms were created in the computer program Open Roads Desinger (ORD). Spatial models were used for the calculation of bauxite reserves, using the computer modeling method (MRM), and the creation of proposals for the development of new mining works
Studija izvodljivosti projekta hvatanja i korištenja ugljika (HKU) na primjeru hrvatskog LNG terminala : diplomski rad
No full textCarbon capture projects are becoming more common around the world. After capture, carbon dioxide can be stored (CCS), utilized (CCU), or both (CCUS). Projects based on carbon capture from flue gases have, so far, largely focused on CCS to hedge the future cost of CO2 allowances, e.g. in the EU ETS, for the emitter. Some have focused on EOR as a CCUS technology. However, almost none have focused on pure utilization (CCU) of carbon dioxide as a product, even though carbon dioxide is a very important gas for industry and the economy, with numerous applications. Recent turbulences in the supply of CO2 and the significant rise of CO2 prices, coupled with the development of innovative products using CO2 as a feedstock, might provide more opportunity to focus on utilization of the CO2 in carbon capture projects. This master’s thesis presents an example of a feasibility study of a CCU project along with a comprehensive overview of technologies for carbon capture and of many possible uses of carbon dioxide. The feasibility study is provided mainly as a techno-economic analysis with consideration of some legislative aspects of the project. A practical description of functioning of the EU ETS is provided in the introduction. Cases are based on the Croatian LNG terminal as the emitter of carbon dioxide which could potentially install a carbon capture system. Real-world information about functioning of the LNG terminal was provided by LNG Croatia LLC, including flue gas compositions and properties. Carbon dioxide emissions at the LNG terminal result from Wärtsilä generating sets that the plant uses to produce its own electrical energy necessary for the functioning of the terminal. The techno-economic analysis is provided in two separate chapters. The technological analysis is provided through simulation and modelling of an amine carbon capture plant in Aspen HYSYS, while the economic analysis is provided through a detailed explanation of foundational assumptions for the analysis and, then, through calculations of CAPEX, OPEX, NPV, and specific production costs of CO2 for each case. Three cases are presented and analysed. Settings and results of modelling in HYSYS are provided in extensive detail, in part to also potentially serve any future researchers. Assumptions for the economic analysis are also based on real-world industry sources, which increases the accuracy of the results. Finally, possible future research directions are presented as well.Projekti hvatanja ugljika postaju sve češći u svijetu. Nakon hvatanja, ugljikov dioksid se može skladištiti (CCS), koristiti (CCU) ili oboje (CCUS). Projekti hvatanja ugljika iz dimnih plinova su se, dosad, uglavnom usredotočivali na CCS radi hedžiranja budućeg troška emisijskih dozvola, npr. u EU ETS-u, za emitera. Neki su se usredotočili na EOR kao CCUS tehnologiju. Međutim, gotovo nijedni se nisu usredotočili na čisto korištenje (CCU) ugljikovog dioksida kao proizvoda, iako je ugljikov dioksid vrlo važan plin za industriju i gospodarstvo, s mnogobrojnim primjenama. Nedavne turbulencije u dobavi CO2 i značajan rast cijena CO2, zajedno s razvojem inovativnih proizvoda koji koriste CO2 kao sirovinu, mogli bi pružiti više prilika za usredotočivanje na upotrebu CO2 u projektima hvatanja ugljika. Ovaj diplomski rad predstavlja primjer studije izvodljivosti CCU projekta zajedno s opsežnim pregledom tehnologija za hvatanje ugljika i mnogih mogućih upotreba ugljikovog dioksida. Studija izvodljivosti je dana primarno kao tehno-ekonomska analiza s razmatranjem nekih pravnih aspekata projekta. Praktičan opis funkcioniranja EU ETS-a je dan u uvodu. Slučajevi se temelje na hrvatskom LNG terminalu kao emiteru ugljikovog dioksida koji bi potencijalno mogao instalirati sustav za hvatanje ugljika. Stvarne informacije o funkcioniranju LNG terminala ustupljene su od strane LNG Hrvatske d.o.o., uključujući sastav i svojstva dimnog plina. Emisije ugljikovog dioksida na LNG terminalu dolaze iz Wärtsilinih motora koji služe za proizvodnju vlastite električne energije potrebne za funkcioniranje terminala. Tehno-ekonomska analiza dana je u dva zasebna poglavlja. Tehnološka analiza je dana kroz simulaciju i modeliranje aminskog postrojenja za hvatanje ugljika u programu Aspen HYSYS, dok je ekonomska analiza dana kroz detaljno objašnjenje temeljnih pretpostavki za analizu te, zatim, kroz izračune CAPEX-a, OPEX-a, NPV-a i specifičnih proizvodnih troškova CO2 za svaki slučaj. Tri slučaja su predstavljena i analizirana. Postavke i rezultati modeliranja u programu HYSYS dani su s opsežnim detaljima, djelomice zato da bi možda poslužili i nekim budućim istraživačima. Pretpostavke za ekonomsku analizu također se temelje na stvarnim izvorima iz industrije, što povećava točnost rezultata. Zaključno, predstavljeni su i mogući budući smjerovi istraživanja
Ubrzanje primjene tehnologija vodika : završni rad
No full textAnaliziran je potencijal vodika kao alternativnog goriva za domaće letove u Hrvatskoj, uz detaljan proračun potrebnih količina i troškova, te infrastrukturnih zahtjeva za njegovu implementaciju. Procjene su pokazale da bi godišnja potreba za vodikom iznosila oko 286 672 kg, što je tehnički moguće skladištiti u samoj zračnoj luci, ali uz značajno povećanje u odnosu na trenutne troškove goriva. Istaknuta je važnost podzemnog skladištenja vodika kao ključnog elementa za stabilizaciju opskrbe, omogućujući balans između proizvodnje i potrošnje. Predviđa se da bi, uz tehnološki napredak i smanjenje cijena obnovljivih izvora energije, troškovi proizvodnje vodika mogli postati konkurentniji do 2030. godine, što bi moglo poboljšati ekonomsku izvedivost projekta
Karotažna mjerenja dielektrične permitivnosti : završni rad
No full textDielektrična karotaža je geofizička metoda koja omogućava precizno razlikovanje vode od nafte na temelju dielektrične permitivnost. Primjenom visokih frekvencija tijekom mjerenja u bušotini, ova metoda može odrediti otpornost i dielektričnu konstantu stijene u horizontalnom i vertikalnom smjeru. Povećanjem frekvencije odašiljača na sondi smanjuje se opseg mjerenja. Cilj ovog rada je istaknut značaj dielektrične konstante, predstaviti dugačku povijest dielektrične karotaže i na koji način nova generacija dielektričnih sondi može pridonijeti istraživanju naftnih ležišta