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•Multi-way analysis classifies crude oil samples by their origin.•DOSY NMR spectra are good experimental data for predicting crude oil stability.•Machine learning enables accurate ...predictive stability models.•Robust approach shows a great potential for practical applications.
Crude oils are extremely complex organic mixtures, composed of various constituents ranging in size, shape and polarity. Obtaining a detailed insight into the petroleum composition is of highest priority for quality evaluation of crude oils and crude oil product performances. The stability of crude oils and their components represents one of the major challenges in petroleum industry, since there is no existing single method to determine the stability of all fractions. In this study, statistical multi-way analysis (MWA) and machine learning (ML) methods were coupled with diffusion-ordered NMR spectroscopy (DOSY) and compared to different crude oil stability affecting parameters in order to explore possibilities to predict crude oil stability. The potential of this approach was explored to identify and classify the crude oils of different origin according to their composition, stability, density and diffusion properties. With the application of MWA using the TUCKER3 decomposition model for a set of DOSY NMR spectra, the principal components were determined for the model (5,5,5), which described 99.89 % of the total variance. The reduced space of the first 3 principal components was used for the sample classification. Similar samples were identified, and reduced space was further utilized for the regression of measured stabilities. Extensive ML multivariate linear regression was carried out for modeling crude oil stability in relation to DOSY NMR spectra and other measured properties, such as aromaticity, API gravity, percentage of aliphatic chains, asphaltene content and relative diffusivities. In both MWA and ML cases the best predictive models were determined. For such complex mixtures as crude oils are, exceptionally good correlations were obtained, proving that this new and robust model can accurately predict crude oil stability and other important parameters relevant for petroleum industry thus showing a great potential for practical applications.
NMR spectroscopy in combination with statistical methods was used to study vacuum residues and vacuum gas oils from 32 crude oils of different origin. Two chemometric metodes were applied. Firstly, ...principal component analysis on complete spectra was used to perform classification of samples and clear distinction between vacuum residues and vacuum light and heavy gas oils were obtained. To quantitatively predict the composition of asphaltenes, principal component regression models using areas of resonance signals spaned by 11 frequency bins of the ¹H NMR spectra were build. The first 5 principal components accounted for more than 94 % of variations in the input data set and coefficient of determination for correlation between measured and predicted values was R.sup.2 = 0.7421. Although this value is not significant, it shows the underlying linear dependence in the data. Pseudo two-dimensional DOSY NMR experiments were used to assess the composition and structural properties of asphaltenes in a selected crude oil and its vacuum residue on the basis of their different hydrodynamic behavior and translational diffusion coefficients. DOSY spectra showed the presence of several asphaltene aggregates differing in size and interactions they formed. The obtained results have shown that NMR techniques in combination with chemometrics are very useful to analyze vacuum residues and vacuum gas oils. Furthermore, we expect that our ongoing investigation of asphaltenes from crude oils of different origin will elucidate in more details composition, structure and properties of these complex molecular systems. Keywords: NMR, PCA, PCR, crude oils, vacuum residues and gas oils, asphaltenes
Adsorption is one of the effective methods of advanced wastewater treatment, which industries employ to reduce hazardous organic and inorganic wastes in effluents. The use of low cost adsorbent has ...been investigated as a replacement for current costly methods of removing toxic substances from wastewater. In this article, the use of low cost adsorbents for the removal of toxic substances from wastewater has been reviewed.
Copper oxide micro-particles immobilised on diatomite surface were prepared by coating diatomite from the solution of copper(II) salts under the room conditions followed by a thermal transformation ...or sintering at the two different temperatures (900
°C and 1100
°C). The purpose of these investigations was to develop a method for detection and identification of copper on a modified diatomite. Characterisation of copper-modified diatomite was performed by the abrasive stripping voltammetry and compared with the X-ray diffraction on powder (XRD) and scanning electron microscopy (SEM) results. XRD results obtained at different sintering temperatures reveal formation of mixtures of phases with tenorite (CuO) and cuprite’s (Cu
2O) structures. Microstructure of the copper-modified diatomite changes at applied sintering temperatures, as can be seen by SEM, while rising of sintering temperature increases agglomeration.
Mazivo za horizontalne busotine primjenjuje se u isplakama za povecanje njezinih podmazujucih svojstava prilikom provedbe postupaka busenja. Dobro podmazuju}e svojstvo isplake je vrlo znacajno zbog ...znatne ustede vremena, produzenja trajnosti opreme, smanjivanja broja manevara i isplativije provedbe ukupnog postupka busenja. Primjenom ekoloskih povoljnih sirovina u mazivima moguce je sprijeciti zagadivanje okolisa (tla i vode). Repicino ulje spada u grupu baznih ulja prihvatljivih za okolis te osim lake i relativne brze biorazgradnje ima i druga povoljna svojstva: dobru mazivost, visoku viskoznost, dobru prionljivost na metalne povrsine i vrlo dobru podnosljivost na opterecenja. Losa primjenska svojstva repicinog ulja: ponasanja na visokoj i niskoj temperaturi, hidroliticka stabilnost te svojstvo pjenjenja moguce je poboljsati ugradnjom odgovarajucih aditiva.
KOMPLEKSNA EVALUACIJA NAFTA Maja Fabulic Ruszkowski; Ljiljana Marinic Pajc; Telen, Sanda ...
Goriva i maziva,
09/2014, Volume:
53, Issue:
3
Journal Article
Na svjetskom naftnom trzistu u zadnjih nekoliko godina doslo je do znacajnih promjena koje su utjecale na preispitivanje postupka nabave nafte u naftnim kompanijama. Pravilnim odabirom nafta mogu se ...znacajno smanjiti troskovi. Odabirom nafta Ina slijedi trendove i kontinuirano se prilagodava novim trzisnim uvjetima. S obzirom na mediteranski polozaj Hrvatske i raspolozivi naftovod, Ini su vrlo dostupne nafte iz bivsih zemalja Sovjetskog Saveza (Rusija, Kazahstan i Azerbajdzan), kao i nafte s Bliskog istoka. Novitet su zapadnoafricke nafte, posebice nigerijske, koje su zadnjih godina dostupne i na mediteranskom trzistu zahvaljujuci smanjenju uvoza nafte u SAD. Zadnjih nekoliko godina Ina pomno odabire nafte i formira naftnu kosaricu koju cine nafte izabrane s obzirom na dostupnost, cijenu i kvalitetu pogodnu za preradu. Nafte iz naftne kosarice se tehnoloski, a potom i ekonomski evaluiraju. Kada izabrana nafta prode obje evaluacije, izdaje se odobrenje za preradu. Ako je trenutacna cijena evaluirane nafte povoljna, tada se ona kupuje. Naftna kosarica znatno se prosirila te se danas u Ini pored nekoliko standardnih nafta preraduju i druge nafte, a trend je jos vise pratiti promjene na trzistu i preradivati naftne mjesavine visoko i niskosumpornih nafta. Kontinuirano se prikupljaju uzorci potencijalnih nafta iz naftne kosarice te se izraduju karakterizacije nafte ili naftni eseji (eng. crude oil assay). Podaci se koriste za provedbu tehnoloske evaluacije te kao ulazni podaci u softver pomocu kojeg se simulira rafinerijska prerada. U radu ce biti opisan postupak tehnoloske evaluacije i prikazan slucaj evaluacije nigerijske nafte Bonga koja se od ove godine pored jos jedne nigerijske nafte preraduje u INI.
In developing new materials for the sorption of mercury from hydrocarbon mixtures, based on copper-modified diatomaceous earth, sorption of copper from aqueous solutions of Cu2+ ions on natural (Dz) ...as well as on conditioned diatomaceous earth was investigated. Dz was conditioned in two ways, by rinsing (Dz-I) and by hydration (Dz-H-48). Equilibrium and kinetic sorption analysis was performed by a simple batch procedure at 25, 40 and 60 °C; concentration of Cu in solution was measured by atomic absorption spectroscopy. It was found that Dz-I was capable of binding significantly more copper (79.10 mg g-1) than Dz (44.8 mg g-1); increasing temperature diminished the mass of bound copper. Equilibrium sorption of water on Dz, Dz-I and Dz-H-48 was successfully described by the Freundlich model. Sorption kinetics was well approximated by the Lagergren 1st order pseudokinetic model.
U postupku razvoja novih materijala za sorpciju zive iz ugljikovodicnih smjesa na osnovi bakrom modificirane dijatomejske zemlje, istrazena je sorpcija bakra iz vodenih otopina Cu2+ iona na prirodnoj ...(Dz), odnosno predobradenoj dijatomejskoj zemlji. Predobrada Dz provedena je na dva nacina: ispiranjem vodom (Dz-I) ili hidratacijom (Dz-H-48). Ravnotezna i kineticka sorpcijska analiza provedena je jednostavnim sarznim postupkom pri 25, 40 i 60 °C; koncentracija Cu2+ u otopini mjerena je atomskom apsorpcijskom spektrometrijom. Pokazalo se da Dz-I veze znatno vecu masu bakra (79,10 mg g-1) u odnosu na Dz (44,8 mg g-1), pri cemu povisenje temperature smanjuje masu vezanog bakra. Ravnotezna sorpcija bakra na Dz, Dz-I i Dz-H-48 uspjesno se opisuje Freundlichovim modelom. Kinetiku sorpcije moguce je opisati Lagergrenovim pseudokinetickim modelom I. reda.
Lubricant for horizontal wells shall be applied in mud for increasing their lubricating properties during the performance of drilling procedures. A good lubricating property of drilling mud is very ...important for a considerable time-saving, prolongation of equipment durability, reduction of the number of manoeuvres, and more cost-effective operation of the entire drilling procedure. Pollution of the environment (soil and water) is preventable by applying environmentally more advatageous raw materials in lubricants. Rapeseed oils belongs to a group of base oils acceptable for the environment, so, in addition to an easy and relatively fast biodegradation it has also other advantageous properties as good lubricity, high viscosity, good adhesiveness to metal surfaces, and very good loadcarrying properties. It is possible to improve poor application properties of rapeseed oil: behaviour at high and low temperatures, hidrolytic stability, as well as foaming property, by admixing suitable additives.
KOMPLEKSNA EVALUACIJA NAFTA Fabulić Ruszkowski, Maja; Marinić Pajc, Ljiljana; Telen, Sanda ...
Goriva i maziva,
09/2014, Volume:
53, Issue:
3
Paper
Open access
Na svjetskom naftnom tržištu u zadnjih nekoliko godina došlo je do značajnih promjena koje su utjecale na preispitivanje postupka nabave nafte u naftnim kompanijama. Pravilnim odabirom nafta mogu se ...značajno smanjiti troškovi. Odabirom nafta Ina slijedi trendove i kontinuirano se prilagođava novim tržišnim uvjetima. S obzirom na mediteranski položaj Hrvatske i raspoloživi naftovod, Ini su vrlo dostupne nafte iz bivših zemalja Sovjetskog Saveza (Rusija, Kazahstan i Azerbajdžan), kao i nafte s Bliskog istoka. Novitet su zapadnoafričke nafte, posebice nigerijske, koje su zadnjih godina dostupne i na mediteranskom tržištu zahvaljujući smanjenju uvoza nafte u SAD. Zadnjih nekoliko godina Ina pomno odabire nafte i formira naftnu košaricu koju čine nafte izabrane s obzirom na dostupnost, cijenu i kvalitetu pogodnu za preradu. Nafte iz naftne košarice se tehnološki, a potom i ekonomski evaluiraju. Kada izabrana nafta prođe obje evaluacije, izdaje se odobrenje za preradu. Ako je trenutačna cijena evaluirane nafte povoljna, tada se ona kupuje. Naftna košarica znatno se proširila te se danas u Ini pored nekoliko standardnih nafta prerađuju i druge nafte, a trend je još više pratiti promjene na tržištu i prerađivati naftne mješavine visoko i niskosumpornih nafta. Kontinuirano se prikupljaju uzorci potencijalnih nafta iz naftne košarice te se izrađuju karakterizacije nafte ili naftni eseji (eng. crude oil assay). Podaci se koriste za provedbu tehnološke evaluacije te kao ulazni podaci u softver pomoću kojeg se simulira rafinerijska prerada. U radu će biti opisan postupak tehnološke evaluacije i prikazan slučaj evaluacije nigerijske nafte Bonga koja se od ove godine pored još jedne nigerijske nafte prerađuje u INI.
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