Formation Kinetics and Self-Preservation of CO2 Hydrates in the Presence of Carboxylated Multiwall Carbon Nanotubes

2021 ◽  
Author(s):  
Khalik Mohamad Sabil ◽  
Omar Nashed ◽  
Bhajan Lal ◽  
Khor Siak Foo

Abstract Nanofluids are known of having the capability to increase heat and mass transfer and their suitability to be used as kinetic gas hydrate promoters have been recently investigated. They have favorable properties such as high thermal conductivity, large surface area, recyclable, ecofriendly, and relatively cheap that are favorable for kinetic gas hydrate promoters. However, the nanomaterials face challenges related to their stability in the base fluid. Therefore, it is crucial to investigate the impact of surfactant free nanofluid on hydrate formation and dissociation kinetics. In this work, COOH-MWCNT suspended in water is used to study the effect of surfactant free nanofluid on CO2 hydrates formation kinetic and stability. Kinetic study on CO2 hydrates formation as well as self-preservation are conducted in a stirred tank reactor. The kinetic experiments are carried out at 2.7 MPa and 274.15 K. The induction time, initial gas consumption rate, half-completion time t50, semi completion time t95 are measured to evaluate the effect of COOH-MWCNT. Furthermore, the dissociation rate was calculated to assess the impact of COOH-MWCNT on self-preservation at 271.15 K and atmospheric pressure. The results are compared with that of sodium dodecyl sulphate (SDS). The study of CO2 hydrates formation kinetic shows that the induction time is not affected by COOH-MWCNT. The impact of nanofluid is more pronounced during the hydrate growth. The initial formation rate is the highest at 0.01 wt% of COOH-MWCNT whereas 0.01 and 0.03 wt% shows the same and shortest t50. However, t95 found to be decreased with increasing the concentration. The effect of COOH-MWCNT is attributed to the strong functional group. Self-preservation results shows CO2 hydrates are less stable in the presence of COOH-MWCNT. The result of this work may provide significant finding that can be used to developed kinetic gas hydrate promoter based on nanofluid that work better than SDS to eliminate gas hydrate formation in oil and gas pipeline.

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Qiang Zhang ◽  
Qiang Wu ◽  
Hui Zhang

In order to explore the method of accelerating hydration separation process to recover methane from mine gas, propane hydrate phase equilibrium was used to measure the equilibrium points of three kinds of mine gas in NaCl solution. Driving force was set as 1 MPa on this basis and high-pressure experimental apparatus of mine gas hydrate was used to carry out the nucleation kinetics experiments of mine gas hydrate for three gas samples in different concentrations of sodium chloride (NaCl) and sodium dodecyl sulfate (SDS) compound systems, which was to study the effect of propane and NaCl-SDS solution on nucleation process of mine gas hydrate. The results showed that induction time of multicomponent mine gas hydrate formation was shortened with the decrease of methane concentration and increase of propane concentration. The induction time of mine gas hydrate formation was shortened with the reduction of NaCl concentration and the increase of SDS concentration. It was found that methane and propane in multicomponent mine gas nucleated collaboratively, which simplified its nucleation process compared with the single component. NaCl has two kinds of functions.


2013 ◽  
Vol 645 ◽  
pp. 146-149 ◽  
Author(s):  
Shi Dong Zhou ◽  
Shu Li Wang ◽  
Guo Zhong Zhang

Capturing carbon dioxide (CO2) by forming hydrate is an attractive technology for reducing the greenhouse effect. The most primary challenges are high energy consumption, low hydrate formation rate, and separation efficiency. In order to solve the problem of slow formation rate of gas hydrate, the effects of sodium dodecyl benzene sulfonate (SDBS), hexadecyl trimethyl ammonium bromide (CTAB) and polyethylene oxide - polypropylene oxide - polyethylene oxide triblock copolymer (P123) on the formation of carbon dioxide hydrate have been investigated.The results show that CTAB, SDBS and P123 can reduce phase equilibrium point of CO2 hydrate. The lower pressure of hydration reaction system ,the larger induction time of CO2 hydrate reduction.Maximum promotion effect of SDBS was observed at 700 mg / kg which was comparable with that of CTAB at 300 mg / kg and P123 at 500 mg / kg. The study has a certain significance to improve the rate of hydrate formation.


2020 ◽  
Vol 10 (15) ◽  
pp. 5052 ◽  
Author(s):  
Sayani Jai Krishna Sahith ◽  
Srinivasa Rao Pedapati ◽  
Bhajan Lal

In this work, a gas hydrate formation and dissociation study was performed on two multiphase pipeline systems containing gasoline, CO2, water, and crude oil, CO2, water, in the pressure range of 2.5–3.5 MPa with fixed water cut as 15% using gas hydrate rocking cell equipment. The system has 10, 15 and 20 wt.% concentrations of gasoline and crude oil, respectively. From the obtained hydrate-liquid-vapor-equilibrium (HLVE) data, the phase diagrams for the system are constructed and analyzed to represent the phase behavior in the multiphase pipelines. Similarly, induction time and rate of gas hydrate formation studies were performed for gasoline, CO2, and water, and crude oil, CO2, water system. From the evaluation of phase behavior based on the HLVE curve, the multiphase system with gasoline exhibits an inhibition in gas hydrates formation, as the HLVE curve shifts towards the lower temperature and higher-pressure region. The multiphase system containing the crude oil system shows a promotion of gas hydrates formation, as the HLVE curve shifted towards the higher temperature and lower pressure. Similarly, the kinetics of hydrate formation of gas hydrates in the gasoline system is slow. At the same time, crude oil has a rapid gas hydrate formation rate.


Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 124 ◽  
Author(s):  
Pandey ◽  
Daas ◽  
Solms

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.


Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3396
Author(s):  
Anatoliy M. Pavlenko

This paper presents the results of a study on the influence of pressure and temperature of the gas–water medium on the process of hydrocarbon gas hydrate formation occurring at the phase interface. Herein, a mathematical model is proposed to determine the optimum ratios of pressure, gas temperatures, water, and gas bubble sizes in the bubbling, gas ejection, or mixing processes. As a result of our work, we determined that gas hydrate in these processes is formed at the gas–water interface, that is, on the boundary surface of gas bubbles. Moreover, there is a gas temperature range where the hydrate formation rate reaches its maximum. These study findings can be used to optimize various technological processes associated with the production of gas hydrates in the industry.


2020 ◽  
Author(s):  
Aliakbar Hassanpouryouzband ◽  
Katriona Edlmann ◽  
Jinhai Yang ◽  
Bahman Tohidi ◽  
Evgeny Chuvilin

<p>Power plants emit large amounts of carbon dioxide into the atmosphere primarily through the combustion of fossil fuels, leading to accumulation of increased greenhouse gases in the earth’s atmosphere. Global climate changing has led to increasing global mean temperatures, particularly over the poles, which threatens to melt gas hydrate reservoirs, releasing previously trapped methane and exacerbating the situation.  Here we used gas hydrate-based technologies to develop techniques for capturing and storing CO<sub>2</sub> present in power plant flue gas as stable hydrates, where CO<sub>2</sub> replaces methane within the hydrate structure. First, we experimentally measured the thermodynamic properties of various flue gases, followed by modelling and tuning the equations of state. Second, we undertook proof of concept investigations of the injection of CO2 flue gas into methane gas hydrate reservoirs as an option for economically sustainable production of natural gas as well as carbon capture and storage. The optimum injection conditions were found and reaction kinetics was investigated experimentally under realistic conditions. Third, the kinetics of flue gas hydrate formation for both the geological storage of CO<sub>2</sub> and the secondary sealing of CH<sub>4</sub>/CO<sub>2</sub> release in one simple process was investigated, followed by a comprehensive investigation of hydrate formation kinetics using a highly accurate in house developed experimental apparatus, which included an assessment of the gas leakage risks associated with above processes.  Finally, the impact of the proposed methods on permeability and mechanical strength of the geological formations was investigated.</p>


2012 ◽  
Vol 616-618 ◽  
pp. 902-906 ◽  
Author(s):  
Chun Long Wang ◽  
Xue Min Zhang ◽  
Jin Ping Li ◽  
Lin Jun Wang ◽  
Liang Jiao

Predicting the driving force accurately is the key process to hydrate nucleating and growing of hydration reaction. The nucleating and growing process of hydrate is relevant to temperature, pressure and component of reactant, and the property of reaction tank and intermiscibility of reactant have notable effect on the formation process of hydrate with its nucleating position, the induction time, growth rate and hydration rate. However, the present driving force model of hydrate cannot predict nucleating area, induction time, growth rate and the reaction limit, and also can't explain the influence of some factors such as cooling rate, temperature disturbance and inlet way on the hydration reaction, it is uncertain of the process to gas hydrate nucleation. We introduced some driving force models, analyzed their merits and demerits, and looked into the distance of research direction to driving force in the future.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yohanes Aris Purwanto ◽  
Seiichi Oshita ◽  
Yasuhisa Seo ◽  
Yoshinori Kawagoe

Separation process of nonpolar gas hydrate formation in liquid food was experimentally studied under high pressure container. Xenon (Xe) gas was selected as hydrate forming gas and coffee solution was used as a sample of liquid food. The high-pressure stainless steel container having the inner diameter of 60 mm and the volume of 700 mL with a U-shaped stirrer was designed to carry out this experiment. A temperature of 9.0°C and Xe partial pressure of 0.9 MPa were set as a given condition. The experiment was designed to examine the effect of steel screen size, formation rate, temperature condition, and amount of Xe gas dissolving in the solution on the separation process which was indicated by concentration efficiency. Screen size of 200 and 280 mesh resulted in higher concentration efficiency than that of 100 mesh. The higher stirring rate caused the higher formation rate of Xe hydrate and created the smaller Xe hydrate crystals. At the condition giving the same solubility in water, temperature of 14.8°C resulted in lower concentration efficiency than 9.0°C. The increase in the amount of Xe gas dissolving in coffee solution caused the concentration efficiency to decrease; however, the concentration ratio between the final and initial concentration of the solution increased.


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