Special Issue "Analysis and Experimental Study on Natural Gas Hydrate Exploitation Processes"

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Environmental and Green Processes".

Deadline for manuscript submissions: closed (31 December 2020).

Special Issue Editors

Dr. Beatrice Castellani
E-Mail Website
Guest Editor
Department of Engineering, CIRIAF, University of Perugia, Via G.Duranti 67, 06125 Perugia, Italy
Interests: energy storage and energy systems; natural gas hydrates; clathrate hydrates; CO2 capture; energy efficiency; waste management
Special Issues and Collections in MDPI journals
Prof. Dr. Andrea Nicolini
E-Mail Website
Guest Editor
Department of Engineering, University of Perugia, Via G.Duranti 67, 06125 Perugia, Italy
Interests: gas hydrates; sustainable development; energy saving; renewables; energy storage; environmental impact
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

Natural gas hydrates are considered a huge reservoir of methane, with the amount of stored organic carbon twice the amount contained in all currently recoverable worldwide conventional hydrocarbon resources.

Research outcomes from theoretical studies, molecular modeling, and experimental works on the recovery of gas from hydrate in laboratory settings have revealed the possibility of energy production from hydrate resources. Traditional production methods include depressurization, thermal stimulation, in-situ combustion, and chemical injection. In addition, a novel technique based on carbon dioxide injection into methane hydrate, has been proposed to recover methane and simultaneously store carbon dioxide, enhancing the idea of a carbon neutral fuel source.

Nevertheless, several issues need further investigation, for instance, kinetic and thermodynamic aspects, hydrates’ mechanical properties as well as full-scale exploitation processes and related energy and environmental analysis.

This Special Issue “Analysis and Experimental Study on Natural Gas Hydrate Exploitation Processes” will collect new outcomes on the above-mentioned issues and offer the scientific community an opportunity to illustrate their research. Therefore, I invite you to submit original research and review articles on this topic.

Prof. Dr. Beatrice Castellani
Prof. Dr. Andrea Nicolini
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Processes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • natural gas hydrate
  • methane hydrate
  • methane reservoir
  • carbon storage
  • CO2 replacement

Published Papers (5 papers)

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Research

Article
Water Salinity as Potential Aid for Improving the Carbon Dioxide Replacement Process’ Effectiveness in Natural Gas Hydrate Reservoirs
Processes 2020, 8(10), 1298; https://doi.org/10.3390/pr8101298 - 16 Oct 2020
Cited by 9 | Viewed by 649
Abstract
Natural gas hydrates represent a valid opportunity to counteract two of the most serious issues that are affecting humanity this century: climate change and the need for new energy sources, due to the fast and constant increase in the population worldwide. The energy [...] Read more.
Natural gas hydrates represent a valid opportunity to counteract two of the most serious issues that are affecting humanity this century: climate change and the need for new energy sources, due to the fast and constant increase in the population worldwide. The energy that might be produced with methane contained in hydrates is greater than any amount of energy producible with known conventional energy sources; being widespread in all oceans, they would greatly reduce problems and conflicts associated with the monopoly of energy sources. The possibility of extracting methane and simultaneously performing the permanent storage of carbon dioxide makes hydrate an almost carbon-neutral energy source. The main topic of scientific research is to improve the recovery of technologies and guest species replacement strategies in order to make the use of gas hydrates economically advantageous. In the present paper, an experimental study on how salt can alter the formation process of both methane and carbon dioxide hydrate was carried out. The pressure–temperature conditions existing between the two respective equilibrium curves are directly proportional to the effectiveness of the replacement process and thus its feasibility. Eighteen formation tests were realized at three different salinity values: 0, 30 and 37 g/L. Results show that, as the salinity degree increases, the space between CO2 and CH4 formation curves grows. A further aspect highlighted by the tests is how the carbon dioxide formation process tends to assume a very similar trend in all experiments, while curves obtained during methane tests show a similar trend but with some significant differences. Moreover, this tendency became more pronounced with the increase in the salinity degree. Full article
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Article
Integrating Support Vector Regression with Genetic Algorithm for Hydrate Formation Condition Prediction
Processes 2020, 8(5), 519; https://doi.org/10.3390/pr8050519 - 27 Apr 2020
Cited by 1 | Viewed by 928
Abstract
To predict the natural gas hydrate formation conditions quickly and accurately, a novel hybrid genetic algorithm–support vector machine (GA-SVM) model was developed. The input variables of the model are the relative molecular weight of the natural gas (M) and the hydrate formation pressure [...] Read more.
To predict the natural gas hydrate formation conditions quickly and accurately, a novel hybrid genetic algorithm–support vector machine (GA-SVM) model was developed. The input variables of the model are the relative molecular weight of the natural gas (M) and the hydrate formation pressure (P). The output variable is the hydrate formation temperature (T). Among 10 gas samples, 457 of 688 data points were used for training to identify the optimal support vector machine (SVM) model structure. The remaining 231 data points were used to evaluate the generalisation capability of the best trained SVM model. Comparisons with nine other models and analysis of the outlier detection revealed that the GA-SVM model had the smallest average absolute relative deviation (0.04%). Additionally, the proposed GA-SVM model had the smallest amount of outlier data and the best stability in predicting the gas hydrate formation conditions in the gas relative molecular weight range of 15.64–28.97 g/mol and the natural gas pressure range of 367.65–33,948.90 kPa. The present study provides a new approach for accurately predicting the gas hydrate formation conditions. Full article
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Article
Screening of Amino Acids and Surfactant as Hydrate Promoter for CO2 Capture from Flue Gas
Processes 2020, 8(1), 124; https://doi.org/10.3390/pr8010124 - 19 Jan 2020
Cited by 10 | Viewed by 1306
Abstract
In this study, the kinetics of flue gas hydrate formation in bulk water in the presence of selected amino acids and surfactants are investigated. Four amino acids (3000 ppm) are selected based on different hydropathy index. Constant-ramping and isothermal experiments at 120 bar [...] Read more.
In this study, the kinetics of flue gas hydrate formation in bulk water in the presence of selected amino acids and surfactants are investigated. Four amino acids (3000 ppm) are selected based on different hydropathy index. Constant-ramping and isothermal experiments at 120 bar pressure and 1 °C temperature are carried out to compare their hydrate promotion capabilities with surfactant sodium dodecyl sulfate (SDS) (500–3000 ppm) and water. Based on experimental results, we report the correlation between hydrate promotion capability of amino acids and their hydrophobicity. Hydrophobic amino acids show stronger flue gas hydrate promotion capability than water and hydrophilic amino acids. We discuss the controlling mechanisms to differentiate between promoters and inhibitors’ roles among the amino acids. Between 2000–3000 ppm concentrations, hydrophobic amino acids have near similar promotion capabilities as SDS. This research highlights the potential use of amino acids as promoters or inhibitors for various applications. Full article
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Article
Molecular Insights into Cage Occupancy of Hydrogen Hydrate: A Computational Study
Processes 2019, 7(10), 699; https://doi.org/10.3390/pr7100699 - 03 Oct 2019
Cited by 3 | Viewed by 835
Abstract
Density functional theory calculations and molecular dynamics simulations were performed to investigate the hydrogen storage capacity in the sII hydrate. Calculation results show that the optimum hydrogen storage capacity is ~5.6 wt%, with the double occupancy in the small cage and quintuple occupancy [...] Read more.
Density functional theory calculations and molecular dynamics simulations were performed to investigate the hydrogen storage capacity in the sII hydrate. Calculation results show that the optimum hydrogen storage capacity is ~5.6 wt%, with the double occupancy in the small cage and quintuple occupancy in the large cage. Molecular dynamics simulations indicate that these multiple occupied hydrogen hydrates can occur at mild conditions, and their stability will be further enhanced by increasing the pressure or decreasing the temperature. Our work highlights that the hydrate is a promising material for storing hydrogen. Full article
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Article
Insights into Kinetics of Methane Hydrate Formation in the Presence of Surfactants
Processes 2019, 7(9), 598; https://doi.org/10.3390/pr7090598 - 05 Sep 2019
Cited by 14 | Viewed by 1062
Abstract
Sodium dodecyl sulfate (SDS) is a well-known surfactant, which can accelerate methane hydrate formation. In this work, methane hydrate formation kinetics were studied in the presence of SDS using a rocking cell apparatus in both temperature-ramping and isothermal modes. Ramping and isothermal experiments [...] Read more.
Sodium dodecyl sulfate (SDS) is a well-known surfactant, which can accelerate methane hydrate formation. In this work, methane hydrate formation kinetics were studied in the presence of SDS using a rocking cell apparatus in both temperature-ramping and isothermal modes. Ramping and isothermal experiments together suggest that SDS concentration plays a vital role in the formation kinetics of methane hydrate, both in terms of induction time and of final gas uptake. There is a trade-off between growth rate and gas uptake for the optimum SDS concentration, such that an increase in SDS concentration decreases the induction time but also decreases the gas storage capacity for a given volume. The experiments also confirm the potential use of the rocking cell for investigating hydrate promoters. It allows multiple systems to run in parallel at similar experimental temperature and pressure conditions, thus shortening the total experimentation time. Understanding methane hydrate formation and storage using SDS can facilitate large-scale applications such as natural gas storage and transportation. Full article
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