scholarly journals Gas Hydrate Combustion in Five Method of Combustion Organization

Entropy ◽  
2020 ◽  
Vol 22 (7) ◽  
pp. 710
Author(s):  
Sergey Y. Misyura ◽  
Andrey Yu. Manakov ◽  
Galina S. Nyashina ◽  
Olga S. Gaidukova ◽  
Vladimir S. Morozov ◽  
...  
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Thick Layer ◽  
Combustion Products ◽  
Dissociation Rate ◽  
Powder Layer ◽  
Muffle Furnace ◽  
Mixed Gas ◽  
Harmful Emissions ◽  
Burning Coal

Experiments on the dissociation of a mixed gas hydrate in various combustion methods are performed. The simultaneous influence of two determining parameters (the powder layer thickness and the external air velocity) on the efficiency of dissociation is studied. It has been shown that for the mixed hydrate, the dissociation rate under induction heating is 10–15 times higher than during the burning of a thick layer of powder, when the combustion is realized above the layer surface. The minimum temperature required for the initiation of combustion for different combustion methods was studied. As the height of the sample layer increases, the rate of dissociation decreases. The emissions of NOx and CO for the composite hydrate are higher than for methane hydrate at the same temperature in a muffle furnace. A comparison of harmful emissions during the combustion of gas hydrates with various types of coal fuels is presented. NOx concentration as a result of the combustion of gas hydrates is tens of times lower than when burning coal fuels. Increasing the temperature in the muffle furnace reduces the concentration of combustion products of gas hydrates.

scholarly journals Dissociation and Combustion of a Layer of Methane Hydrate Powder: Ways to Increase the Efficiency of Combustion and Degassing

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4855
Author(s):  
Sergey Y. Misyura ◽  
Igor G. Donskoy
Keyword(s):  
Flame Front ◽  
Gas Hydrates ◽  
Methane Hydrate ◽  
Experimental Studies ◽  
Combustion Efficiency ◽  
Dissociation Rate ◽  
Front Velocity ◽  
Powder Layer ◽  
Vapor Concentration ◽  
Efficiency Increase

The interest in natural gas hydrates is due both to huge natural reserves and to the strengthened role of environmentally friendly energy sources conditioned by the deterioration of the global environmental situation. The combustion efficiency increase is associated with the development of understanding of both the processes of dissociation and combustion of gas hydrates. To date, the problems of dissociation and combustion have, as a rule, been considered separately, despite their close interrelation. Usually, during combustion, there is a predetermined methane flow from the powder surface. In the present paper, the combustion of methane hydrate is simulated taking into account the non-stationary dissociation process in the powder layer. Experimental studies on the methane hydrate dissociation at negative temperatures have been carried out. It is shown that due to the increase in the layer temperature and changes in the porosity of the layer over time, i.e., coalescence of particles, the thermal conductivity of the layer can change significantly, which affects the heat flux and the dissociation rate. The flame front velocity was measured at different external air velocities. The air velocity and the vapor concentration in the combustion zone are shown to strongly affect the combustion temperature, flame stability and the flame front velocity. The obtained results may be applied to increase the efficiency of burning of a layer of methane hydrate powder, as well as for technologies of degassing the combustible gases and their application in the energy sector.

scholarly journals Influence of Gas Supply Changes on the Formation Process of Complex Mixed Gas Hydrates

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 3039
Author(s):  
Mengdi Pan ◽  
Judith M. Schicks
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Formation Process ◽  
Gas Flow ◽  
Hydrate Formation ◽  
Experimental Investigations ◽  
Gas Composition ◽  
Mixed Gas ◽  
Hydrate Phase ◽  
Gas Supply

Natural gas hydrate occurrences contain predominantly methane; however, there are increasing reports of complex mixed gas hydrates and coexisting hydrate phases. Changes in the feed gas composition due to the preferred incorporation of certain components into the hydrate phase and an inadequate gas supply is often assumed to be the cause of coexisting hydrate phases. This could also be the case for the gas hydrate system in Qilian Mountain permafrost (QMP), which is mainly controlled by pores and fractures with complex gas compositions. This study is dedicated to the experimental investigations on the formation process of mixed gas hydrates based on the reservoir conditions in QMP. Hydrates were synthesized from water and a gas mixture under different gas supply conditions to study the effects on the hydrate formation process. In situ Raman spectroscopic measurements and microscopic observations were applied to record changes in both gas and hydrate phase over the whole formation process. The results demonstrated the effects of gas flow on the composition of the resulting hydrate phase, indicating a competitive enclathration of guest molecules into the hydrate lattice depending on their properties. Another observation was that despite significant changes in the gas composition, no coexisting hydrate phases were formed.

Basic Research on Reducing Emission of CH4 Based on Gas Hydrate Technology

2010 ◽  
Vol 113-116 ◽  
pp. 1940-1944
Author(s):  
Feng Xu ◽  
Long Jun Xu ◽  
Qiang Wu ◽  
Li Hua Zhu
Keyword(s):  
Natural Gas ◽  
Gas Hydrates ◽  
Coal Mine ◽  
Gas Hydrate ◽  
Storage Stability ◽  
Basic Research ◽  
Dissociation Rate ◽  
Gas Extraction ◽  
Coal Mine Gas ◽  
Mine Gas

Methane (CH4) a potent greenhouse gas (GHG). Human activities, such as natural gas extraction, natural gas transportation and coal mining, result in emissions of the large amounts of CH4 into the atmosphere. Thus it is necessary to study the reduction of CH4 in these fields. The experiments of hydrates formation of CH4 and coal mine gas were respectively carried out using self-developed experiment apparatuses. The results show that the hydrates of CH4 and coal mine gas are prone to be formed under appropriate conditions. The strong storage stability of natural gas hydrates was approved by the experiments to determine the dissociation heat and the average dissociation rate of hydrates. At the same time, the technology flow for recovery and utilization of coal mine gas was proposed based on gas hydrate technology. The experiment results and the former literatures indicate that the reducing emission of CH4 using gas hydrates is feasible.

Thermodynamic Modelling of Gas Hydrate Formation in the Presence of Inhibitors and the Consideration of their Effect

2014 ◽  
Vol 14 (1) ◽  
pp. 45
Author(s):  
Peyman Sabzi ◽  
Saheb Noroozi
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Low Temperatures ◽  
Hydrate Formation ◽  
Transportation Systems ◽  
Flow Lines ◽  
Main Approach ◽  
Efficient Inhibitor ◽  
System A ◽  
Gas Hydrate Formation

Gas hydrates formation is considered as one the greatest obstacles in gas transportation systems. Problems related to gas hydrate formation is more severe when dealing with transportation at low temperatures of deep water. In order to avoid formation of Gas hydrates, different inhibitors are used. Methanol is one of the most common and economically efficient inhibitor. Adding methanol to the flow lines, changes the thermodynamic equilibrium situation of the system. In order to predict these changes in thermodynamic behavior of the system, a series of modelings are performed using Matlab software in this paper. The main approach in this modeling is on the basis of Van der Waals and Plateau's thermodynamic approach. The obtained results of a system containing water, Methane and Methanol showed that hydrate formation pressure increases due to the increase of inhibitor amount in constant temperature and this increase is more in higher temperatures. Furthermore, these results were in harmony with the available empirical data.Keywords: Gas hydrates, thermodynamic inhibitor, modelling, pipeline blockage

Mixed gas sources induced co-existence of sI and sII gas hydrates in the Qiongdongnan Basin, South China Sea

2021 ◽  
Vol 128 ◽  
pp. 105024
Author(s):  
Jiangong Wei ◽  
Tingting Wu ◽  
Linqi Zhu ◽  
Yunxin Fang ◽  
Jinqiang Liang ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Gas Hydrates ◽  
Qiongdongnan Basin ◽  
Mixed Gas ◽  
China Sea

scholarly journals Rapid Gas Hydrate Formation—Evaluation of Three Reactor Concepts and Feasibility Study

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3615
Author(s):  
Florian Filarsky ◽  
Julian Wieser ◽  
Heyko Juergen Schultz
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Synthetic Natural Gas ◽  
Operation Conditions ◽  
Gas Hydrate Formation ◽  
Gas Conditioning ◽  
And Storage ◽  
Economic Considerations ◽  
High Storage

Gas hydrates show great potential with regard to various technical applications, such as gas conditioning, separation and storage. Hence, there has been an increased interest in applied gas hydrate research worldwide in recent years. This paper describes the development of an energetically promising, highly attractive rapid gas hydrate production process that enables the instantaneous conditioning and storage of gases in the form of solid hydrates, as an alternative to costly established processes, such as, for example, cryogenic demethanization. In the first step of the investigations, three different reactor concepts for rapid hydrate formation were evaluated. It could be shown that coupled spraying with stirring provided the fastest hydrate formation and highest gas uptakes in the hydrate phase. In the second step, extensive experimental series were executed, using various different gas compositions on the example of synthetic natural gas mixtures containing methane, ethane and propane. Methane is eliminated from the gas phase and stored in gas hydrates. The experiments were conducted under moderate conditions (8 bar(g), 9–14 °C), using tetrahydrofuran as a thermodynamic promoter in a stoichiometric concentration of 5.56 mole%. High storage capacities, formation rates and separation efficiencies were achieved at moderate operation conditions supported by rough economic considerations, successfully showing the feasibility of this innovative concept. An adapted McCabe-Thiele diagram was created to approximately determine the necessary theoretical separation stage numbers for high purity gas separation requirements.

scholarly journals Effects of Catalysts on Emissions of Pollutants from Combustion Processes of Liquid Fuels

2014 ◽  
Vol 13 (2) ◽  
pp. 5-17
Author(s):  
Agnieszka Bok ◽  
Joanna Guziałowska-Tic ◽  
Wilhelm Jan Tic
Keyword(s):  
Combustion Process ◽  
Combustion Products ◽  
Organometallic Complexes ◽  
Liquid Fuels ◽  
Motor Fuels ◽  
Harmful Emissions ◽  
Fuel Oils ◽  
Sulphur Oxides ◽  
Dynamic Growth ◽  
Combustion Processes

Abstract The dynamic growth of the use of non-renewable fuels for energy purposes results in demand for catalysts to improve their combustion process. The paper describes catalysts used mainly in the processes of combustion of motor fuels and fuel oils. These catalysts make it possible to raise the efficiency of oxidation processes simultanously reducing the emission of pollutants. The key to success is the selection of catalyst compounds that will reduce harmful emissions of combustion products into the atmosphere. Catalysts are introduced into the combustion zone in form of solutions miscible with fuel or with air supplied to the combustion process. The following compounds soluble in fuel are inclused in the composition of the described catalysts: organometallic complexes, manganese compounds, salts originated from organic acids, ferrocen and its derivatives and sodium chloride and magnesium chloride responsible for burning the soot (chlorides). The priority is to minimize emissions of volatile organic compounds, nitrogen oxides, sulphur oxides, and carbon monoxide, as well as particulate matter.

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