Wyniki wyszukiwania - BazTech

1

Self-preservation Effect of Gas Hydrates

Pavlenko Anatoliy

Rocznik Ochrona Środowiska

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2021

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Tom 23

346--355

EN

This work was performed to improve the storage and transportation technology of gas hydrates in nonequilibrium conditions. At atmospheric pressure and positive ambient temperature, they gradually dissociate into gas and water. Simulation of the gas hydrate dissociation will determine optimal conditions for their transportation and storage, as well as minimize gas loss. Thermodynamic parameters of adiabatic processes of forced preservation of pre-cooled gas hydrate blocks with ice layer were determined theoretically and experimentally. Physical and mathematical models of these processes were proposed. The scientific novelty is in establishing quantitative characteristics that describe the gas hydrates thermophysical parameters thermophysical characteristics influence on the heat transfer processes intensity on the interphase surface under conditions of gas hydrates dissociation. Based on the results of experimental studies, approximation dependences for determining the temperature in the depths of a dissociating gas hydrate array have been obtained. Gas hydrates dissociation mathematical model is presented.

2

Thermophysical-based Effect of Gas Hydrates Self-Preservation

Kutnyi Bohdan, Pavlenko Anatoliy, Koshlak Hanna

Rocznik Ochrona Środowiska

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2020

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Tom 22, cz. 1

11--23

EN

To improve gas hydrates dissociation technology, studies of heat transfer processes on the interfacial surface are significant. In the work, experimental and theoretical studies of the gas hydrates dissociation are presented. The scientific novelty is in establishing quantitative characteristics that describe the gas hydrates thermophysical parameters thermophysical characteristics influence on the heat transfer processes intensity on the interphase surface under conditions of gas hydrates dissociation. Based on the results of experimental studies, approximation dependences for determining the temperature in the depths of a dissociating gas hydrate array have been obtained. Gas hydrates dissociation mathematical model is presented. The practical significance of the research results is in determining quantitative indicators of the heat transfer processes intensity under the conditions of propane hydrate dissociation. The results of the work can be applied to designing equipment for gas hydrates storage and dissociation.

PL

Badania procesów wymiany ciepła na powierzchni międzyfazowej mają ogromne znaczenie dla poprawy technologii dysocjacji hydratów gazowych. W pracy przedstawiono eksperymentalne i teoretyczne badania dysocjacji hydratów gazu. Nowość polega na ustaleniu cech ilościowych, które opisują wpływ właściwości termofizycznych hydratów gazu na intensywność procesów wymiany ciepła na powierzchni międzyfazowej w warunkach dysocjacji hydratów gazu. Na podstawie wyników badań eksperymentalnych uzyskuje się zależności aproksymacyjne do określania temperatury na głębokościach dysocjującego układu hydratów gazu. Przedstawiono matematyczny model dysocjacji hydratów gazu. Praktyczne znaczenie wyników badań polega na określeniu ilościowych wskaźników intensywności procesów wymiany ciepła w warunkach dysocjacji hydratu propanu. Wyniki można zastosować w projektowaniu urządzeń do magazynowania i dysocjacji hydratów gazu.

3

Influence of nitrogen on thermodynamic properties and plasma composition in discharge tube of CO-laser

Grigorian G. M., Cenian A.

Archives of Thermodynamics

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2016

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Vol. 37, no. 3

31--43

EN

The role of the addition of nitrogen to the discharge plasma of CO lasers on thermodynamic properties and composition of the laser active medium is discussed here. It is shown that nitrogen addition improves laser characteristics and changes the composition of the laser active medium. The addition of nitrogen significantly decreases CO dissociation level and concentrations of C atoms created in plasma-chemical reactions of laser discharge.

4

Apparatus to study volumetric properties of the gas hydrates

Lorenc M., Warowny W.

AGH Drilling, Oil, Gas

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2012

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Vol. 29, no. 3

419--430

EN

A new pVT apparatus was built on Department of Drilling, Oil and Gas at AGH University of Science and Technology, which was sponsored by the Polish Oil and Gas Company. The apparatus was adjusted to measurement of the proprieties of the gas hydrates. On the schematic diagram of this apparatus, methodological solutions of the equipment were compared to different of this kind literature apparatuses. Among others innovatory elements of the present apparatus some of them should be counted: method of the changes of volume or automatic system (arrangement) to taking the sample with supported nafion drying. The first step of the experimental study is desulfurization of the natural, by using process of the hydrates formation in gas mixture.

5

Zjawiska dysocjacji i asocjacji towarzyszące reakcjom przeniesienia protonu między C-kwasami i zasadami organicznymi w rozpuszczalnikach aprotonowych

Nowak I., Binkowska I., Stańczyk-Dunaj M., Jarczewski A.

Wiadomości Chemiczne

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2008

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[Z] 62, 1-2

67-95

EN

The proton transfer reactions in solutions have attracted the attention of a number of laboratories for many years. These processes seem to be quite simple as they proceed without perturbation of bounding electrons and have low steric demands what enables study of their mechanism. However, many factors influences the mechanisms of these reactions. Among them and not the trifling ones, are dissociation-association effects accompanying them. The definition, behavior and reactivity of carbon acids (C-acids) depending on the type of electron withdrawing group are given [1-57]. Also the values of dissociation constants of C-acids in protic and aprotic solvents are collated in Tables 4, 5 and 7 [11, 38, 49]. The nature of products, free ions and ion pairs, of proton transfer reactions of various C-acids and strong organic bases are carefully discussed. Also their spectral characteristics are given. The equilibria and the possible routes between the substrates and the products of these reactions are also shown [58-66]. The reasons of the homoconjugation effects as a result of an association of the ionic products of the proton transfer reactions in different solvents are discussed in the context of their solvation abilities [67-86]. The formation constants of the homoconjugation complexes of amidine and guanidine bases in relation to their pK? values are quoted in Table 6 [87-95]. The nature of heteroconjugation complexes formed as the result of hydrogen bonding of different entities in the system of proton transfer reactions is discussed [96-116]. The pK? values of a number of C-acids, derivatives of nitromethane, measured in acetonitrile by potentiometric method, are given in Table 7. The pK? values of these derivatives measured in DMSO/H2O systems are compared with those obtained in acetonitrile [18, 38]. The general view of these problems is discussed and carefully reviewed.

6

Piroliza, dysocjacja i spalanie fazy stałej w analizie termicznej

Mianowski A.

Przemysł Chemiczny

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2006

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T. 85, nr 8-9

1049-1053

PL

Analiza termiczna procesów dysocjacji związków chemicznych, pirolizy (węgli kamiennych, paków węglowych i mezofazowych, odpadowych poliolefin) i spalania różnych nośników pierwiastka C opiera się na równaniach termokinetycznych, w których wykorzystuje się prawo Arrheniusa. Jednocześnie rolę czasu przejmuje temperatura, wzrastająca proporcjonalnie do czasu. Omówiono metody klasyczne i nowsze, oparte na równaniu trójparametrycznym. Przeprowadzono dyskusję nad efektem izokinetycznym przy wykorzystaniu równania Eyringa. Przedstawione rozważania umożliwiają dokonanie selekcji spośród bardzo wielu możliwości interpretacji danych termograwimetrycznych. Zwrócono uwagę na praktyczne wykorzystanie wyników badań, dla niektórych procesów hutniczych (COS) i koksowniczych (oczyszczanie komór koksowniczych z depozytów grafitowych).

EN

A review with 39 refs. covering pyrolysis of coal, coal-tar and mesophase pitches, and waste polyolefins, and combustion of various C carriers, analysis in terms of thermokinetic equations using Arrhenius law, discussion of the isokinetic effect based on Eyring’s equations, and practical directions on how to make use of studies carried out on some metallurgical processes (cont. steel casting) and on C deposits from coking chambers.

7

Electron impact excitation and dissociation of halogen-containing molecules

Kitajima M., Suzuki R., Tanaka H., Pichl L., Cho H.

Nukleonika

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2003

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Vol. 48, nr 2

89-93

EN

A systematic analysis of the absolute differential cross sections (DCSs) for electron scattering by halogen-containing molecules CF3X (X = H, F, Cl, Br, I) has been performed with impact energy and scattering angle ranging from 1.5 to 100 eV and 15 to 130°, respectively. Three of the results of these experiments are described in the present report. Firstly, a clear difference is demonstrated in the elastic-scattering cross section angular distributions of polar and nonpolar molecules with the substitution of one of the F atoms in CF4 for a H, Cl, Br or I atom. Secondly, vibrational excitation spectra of the unresolved composite modes (mainly CF3 stretching) for CF3X reveal a common broad structure in the region from 7 to 9 eV due to shape resonance. The third result presented is the observation of a low-lying electronic state of CF3Cl, CF3Br, and CF3I. This feature is enhanced at lower incident energies and larger scattering angles. Also discussed are some preliminary results on the formation of negative and neutral fragments from SiF4 and CH4 by electron impact.

8

Doświadczalno-teoretyczne studium zjawisk powstawania i dysocjacji hydratów gzu ziemnego

Lubaś J.

Prace Instytutu Górnictwa Naftowego i Gazownictwa

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2002

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nr 117

1--103

PL

W pracy przedstawiono wyniki wieloletnich badań autora nad zjawiskami tworzenia i dysocjacji hydra¬tów gazu ziemnego wykonanych z wykorzystaniem zmodyfikowanej aparatury PVT w Laboratorium Badania Złóż IGNiG. Pozwoliły one zweryfikować program zbudowany w oparciu o zasady termodynamiki równowagowej oraz własny wykorzystujący algorytm równań Istomina a następnie uwidocznić zasadniczy wpływ zawartości siarkowodoru i azotu na przebieg krzywych dysocjacji hydratów. Badając zjawisko metastabilności hydratów wykazano, że hydraty powstają w warunkach, które określa krzywa tworzenia nie pokrywająca się jak dotychczas sądzono z krzywą dysocjacji. Zastosowanie rachunku sieci neuronowych pozwoliło wykluczyć wpływ składu chemicznego gazu na wielkość średniej temperatury przechłodzenia określającej wielkość obszaru metastabilności. Znaczna część pracy dotyczy zagadnień technologicznych związanych z zastosowaniem optymalnych metod przeciwdziałania zjawiskom tworzenia hydratów. Opracowano w niej metodykę lokalizacji interwałów zagrożonych powstawaniem hydratów w odwiertach jak również przedstawiono sposoby uzbrojenia wgłębnego z wykorzystaniem kolumny cyrkulacyjnej i metody wtłaczania gorącego medium. W oparciu o obliczenia wykorzystujące równania bilansu energetycznego w przepływie jednofazowym oraz modelowania VFP z pakietu Eclipse przedstawiono oryginalną koncepcję wykorzystania płynów o niskim współczynniku przenikania ciepła wypełniających przestrzeń pierścieniową odwiertu. Stosując program obliczeniowy PVT SIM oraz wyniki badań doświadczalnych opracowano kryteria i zakresy zastosowania poszczególnych inhibitorów hydratów. Omówiono również zjawiska tworzenia i dysocjacji hydratów gazu ziemnego w warunkach złożowych szczególnie w odniesieniu do warunków termodynamicznych panujących w akwenie Morza Bałtyckiego.

EN

Presented are results of laboratory tests on formation and dissociation of natural gas hydrates. The lab tests were performed in IGNiG laboratories using the modified PVT equipment. The tests results allowed us to asses reliability of computer programs i.e. the program based on statistical thermodynamic principles and the program based on Istomin equilibrium algorithm. Results indicated strong impact of H2S and nitrogen content on hydrate dissociation. It had been demonstrated that the hydrates formation are rather governed by the so called „hydrate formation curve" instead of „dissociation curve" - which is in opposition to what was suggested before. Calculations performed using the artificial neural network indicated that the chemical composition of gas has no impact on supercooling temperature which defines the envelope of hydrate metastability region. Discussed are the methods of preventing the hydrate formation and the procedure is presented which allows us to find the place where hydrate plugs are formed within the gas well. Hydrate removal procedures are discussed including the fluid recirculation and hot fluid injection methods. Presented is the original concept which consist in filling the gas well annular with fluids having the low heat transfer coefficient. This concept is supported by energy balance for single phase flow and VFP program. Provided are criteria for selection of hydrate inhibitors. Discussed are the formation and dissociation of gas hydrates in thermodynamic conditions prevailing in the Baltic Sea region.

9

Analysis of annular detonation wave characteristics, propagating in explosive gas mixture

Włodarczyk E.

Problemy Techniki Uzbrojenia

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2001

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R. 30, z. 79

19--35

EN

Theoretical, qualitative and quantitative analysis of annular detonation wave parameters are carried out. In accordance to the theory of detonation optics, the chemical reaction zone is replaced by surface of strong discontinuity. This surface is termed the detonation wave front. It was found that in the upper layer of the cylindrical charge (more than 0.5r0 thick the explosive gas mixture) the annular detonation wave propagates with velocity comparable to the Chapman-Jouguet velocity, and its front is similar to the half-tours surface. The radial cumulation of the annular detonation wave parameters occurs in the direct neighborhood of the charge axis. All the parameters, except of the specific volume, increase to infinity when the charge radius decreases to zero. The phenomena of the dissociation and ionization of detonation product in the cumulation state have been neglected, therefore the results obtained in the direct neighbourhood of the charge axis have a qualitative character.

10

Influence of the temperature of preparation process on refractive index of sol-gel matrices.

Lechna-Marczyńska M., Podbielska H.

Optica Applicata

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2001

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Vol. 31, nr 1

257-261

EN

The preparation of sol-gel materials in the form of bulks and thin films at different temperatures is described The procedure involves running the reaction at 50 degrees C and 90 degrees C in an open vessel. Such an approach enables acceleration of hydrolysis and condensation reactions. This procedure yields crack-free sol-gel glasses. The changes in refractive index of sol-gel materials were studied by using a Pulfrich refractometer. The experimental data indicates significant differences in the optical properties of sol-gel glasses, depending on the temperature during the preparation. The samples show normal dispersion, whereas a higher refractive index was stated for films prepared at a higher temperature.

11

Metoda regulowanego azotowania gazowego "Nitreg"

Różycki R., Smolik J.

Problemy Eksploatacji

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1999

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nr 4

155-166

PL

W artykule przedstawiono metodę regulowanego azotowania gazowego „Nitreg". Opisano konstrukcję i zasadę działania urządzenia technologicznego typu NX-811, wykorzystującego zasadę kontroli potencjału azotowego według metody „Nitreg". Przedstawione zostały przykłady zastosowania azotowania gazowego „Nitreg" w celu ulepszenia warstwy wierzchniej detali ze stali narzędziowej stopowej do pracy na gorąco. Zamieszczone zostały wyniki badań metalograficznych, wykazujące różnice strukturalne warstw azotowanych w zależności od parametrów technologicznych procesu azotowania.

EN

Modern process control technology has allowed the transformation of gas nitriding into an efficient and predictable technology, successful in a wide variety of steels and applications. It is competitive with another clean technology of plasma nitriding, featuring fewer of the latter's limitations. It is very successful as a replacement for salt bath treatments. In the case of gas nitriding the only noxious effluent is gaseous ammonia which is routinely eliminated in recently developed neutralizing burners, or standard dissociators. There are no solid or liquid residues to be treated. Controlled gas nitriding is gaining a gradually growing acceptance in the manufacturing industry as a cost-effective, versatile and reliable method of enhancing the surface properties of steel parts and tools. The cost effectiveness relates to overall manufacturing costs, and in particular to a possible reduction in finishing costs of parts of more complex shape, due to negligible distortion and insignificant dimensional changes occurring during nitriding.

12

General formula for shape-resonance life times: the HeH(+) example

Peek J.M.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 7S

1334-1342

EN

Translational spectroscopy stimulated the investigation of shape resonances in the electronic ground state of HeH(+) a number of years ago. Subsequent spectroscopic studies have increased the accuracy of these experimental data. Theoretical investigations require an extremely accurate potential energy curve over an extended range of internuclear separation. The calculation by Kołos proved invaluable in identifying these states and continues to be the standard to which improvements are added. The accurate characterization of many isolated shape resonances may be necessary so convenient techniques are required. Test functions are often used to create a boundary condition that converts this problem in the continuum to a discrete state calculation. The resulting eigenvalue search is efficient and convenient to automate. The associated widths are usually found by other techniques. It is shown here that the eigenvalue calculation implies a width if one convenient and easily satisfied requirement is met. Two versions of this result are applied to selected experimantal data for HeH(+).