Design and numerical simulation of a microwave antenna with coaxial slots for preventing secondary formation of gas hydrate

Gas hydrate is a new clean energy resource with polar molecule. However due to the change of temperature and pressure during extraction process, there will be secondary formation of gas hydrate, which usually occurs in reservoirs or pipelines near the wellhead. It is significance to prevent secondary formation of hydrate because of safety issues or production rate reduction caused by it. Theoretically, microwave heating can accelerate the decomposition of gas hydrate. Therefore, it is possible to use microwave radiation to prevent secondary formation of hydrate. In this paper, a microwave antenna with special shaped coaxial-slots was designed. Based on electromagnetics and antenna transmission theories, the key parameters of the coaxial-slot antenna were calculated. The frequency is 2.45 GHz, the impedance is 50 ohms, and ratio of outer to inner conductor radius is 3.32. The slots were designed as ‘H’-shape with the width is 2 mm, the radial length is 12mm, the axial length is 14 mm and the interval is 35 mm. Teflon was used as filling material and the radome. Then the software HFSS and ANSYS were used to analyze the electromagnetic field and temperature field to further optimize the parameters. It will be proved that the microwave antenna can heat gas hydrate and prevent the secondary formation.

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Research Status and Trend of Natural Gas Hydrate in China

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.978.165 ◽

2014 ◽

Vol 978 ◽

pp. 165-168 ◽

Cited By ~ 1

Author(s):

Rong Huo ◽

Kai Bo Duan

Keyword(s):

Natural Gas ◽

Gas Hydrate ◽

Alternative Energy ◽

Energy Resource ◽

Clean Energy ◽

Development Trend ◽

Research Progress ◽

Natural Gas Hydrate ◽

Environment Quality ◽

Further Development

With the further development of national economy, people have become more concerned about the environment quality. Especially in recent years, due to the frequent occurrence of hazy weather, there has been a growing demand for clean energy [Fig. 1]. As one kind of non-conventional energy, natural gas hydrate, featured by large reserves and relatively clean products of combustion, is considered by the scientific community to be an alternative energy resource in replacement of coal and petroleum. This paper gives a brief introduction of the research progress of natural gas hydrate both at home and abroad, presents the research results and the obstacles in the next step to be taken for China, and then looks into the future development trend.

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Focus on the development of natural gas hydrate in China

10.20944/preprints201607.0041.v1 ◽

2016 ◽

Author(s):

Zhongfu Tan ◽

Ge Pan ◽

Pingkuo Liu

Keyword(s):

Natural Gas ◽

Future Development ◽

Gas Hydrate ◽

Energy Resource ◽

Clean Energy ◽

Development Trend ◽

Natural Gas Hydrate ◽

The World ◽

The Future ◽

Resource Shortage

Natural gas hydrate, also known as combustible ice and mainly composed of methane, it is identified as the potential clean energy in the 21th century. Due to its large reserves, gas hydrate can ease problems caused by energy resource shortage and has gained attention around the world. In this paper, we focus on the exploration and development of gas hydrate as well as discussing its status and future development trend in China and abroad, then we analyze its opportunities and challenges in China from four aspects: resource, technology, economy and police with five forces model and PEST method. The results show, China has abundance gas hydrate resource; however the backward technologies and inadequate investment has seriously hindered the future development of gas hydrate, so China should establish relevant cooperation framework and intuitional arrangement to attract more investment as well as breaking through technical difficulties to make gas hydrate commercialization as soon as possible.

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Wave Propagation Characteristics in Gas Hydrate-Bearing Sediments and Estimation of Hydrate Saturation

Energies ◽

10.3390/en14040804 ◽

2021 ◽

Vol 14 (4) ◽

pp. 804

Author(s):

Lin Liu ◽

Xiumei Zhang ◽

Xiuming Wang

Keyword(s):

Gas Hydrate ◽

Clay Content ◽

Clean Energy ◽

Compressional Wave ◽

Physical Parameters ◽

Well Log ◽

Log Data ◽

Phase Velocities ◽

Hydrate Saturation ◽

Hydrate Bearing Sediments

Natural gas hydrate is a new clean energy source in the 21st century, which has become a research point of the exploration and development technology. Acoustic well logs are one of the most important assets in gas hydrate studies. In this paper, an improved Carcione–Leclaire model is proposed by introducing the expressions of frame bulk modulus, shear modulus and friction coefficient between solid phases. On this basis, the sensitivities of the velocities and attenuations of the first kind of compressional (P1) and shear (S1) waves to relevant physical parameters are explored. In particular, we perform numerical modeling to investigate the effects of frequency, gas hydrate saturation and clay on the phase velocities and attenuations of the above five waves. The analyses demonstrate that, the velocities and attenuations of P1 and S1 are more sensitive to gas hydrate saturation than other parameters. The larger the gas hydrate saturation, the more reliable P1 velocity. Besides, the attenuations of P1 and S1 are more sensitive than velocity to gas hydrate saturation. Further, P1 and S1 are almost nondispersive while their phase velocities increase with the increase of gas hydrate saturation. The second compressional (P2) and shear (S2) waves and the third kind of compressional wave (P3) are dispersive in the seismic band, and the attenuations of them are significant. Moreover, in the case of clay in the solid grain frame, gas hydrate-bearing sediments exhibit lower P1 and S1 velocities. Clay decreases the attenuation of P1, and the attenuations of S1, P2, S2 and P3 exhibit little effect on clay content. We compared the velocity of P1 predicted by the model with the well log data from the Ocean Drilling Program (ODP) Leg 164 Site 995B to verify the applicability of the model. The results of the model agree well with the well log data. Finally, we estimate the hydrate layer at ODP Leg 204 Site 1247B is about 100–130 m below the seafloor, the saturation is between 0–27%, and the average saturation is 7.2%.

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Evaluation and re-understanding of the global natural gas hydrate resources

Petroleum Science ◽

10.1007/s12182-021-00568-9 ◽

2021 ◽

Vol 18 (2) ◽

pp. 323-338

Author(s):

Xiong-Qi Pang ◽

Zhuo-Heng Chen ◽

Cheng-Zao Jia ◽

En-Ze Wang ◽

He-Sheng Shi ◽

...

Keyword(s):

Natural Gas ◽

Gas Hydrate ◽

Oil And Gas ◽

Material Balance ◽

Energy Resource ◽

Resource Assessment ◽

Future Trend ◽

Natural Gas Hydrate ◽

The Future ◽

Recoverable Resources

AbstractNatural gas hydrate (NGH) has been widely considered as an alternative to conventional oil and gas resources in the future energy resource supply since Trofimuk’s first resource assessment in 1973. At least 29 global estimates have been published from various studies so far, among which 24 estimates are greater than the total conventional gas resources. If drawn in chronological order, the 29 historical resource estimates show a clear downward trend, reflecting the changes in our perception with respect to its resource potential with increasing our knowledge on the NGH with time. A time series of the 29 estimates was used to establish a statistical model for predict the future trend. The model produces an expected resource value of 41.46 × 1012 m3 at the year of 2050. The statistical trend projected future gas hydrate resource is only about 10% of total natural gas resource in conventional reservoir, consistent with estimates of global technically recoverable resources (TRR) in gas hydrate from Monte Carlo technique based on volumetric and material balance approaches. Considering the technical challenges and high cost in commercial production and the lack of competitive advantages compared with rapid growing unconventional and renewable resources, only those on the very top of the gas hydrate resource pyramid will be added to future energy supply. It is unlikely that the NGH will be the major energy source in the future.

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Can Hydropower Still Be Considered a Clean Energy Source? Compelling Evidence from a Middle-Sized Hydropower Station in China

Sustainability ◽

10.3390/su11164261 ◽

2019 ◽

Vol 11 (16) ◽

pp. 4261 ◽

Cited By ~ 2

Author(s):

Xuerong Li ◽

Faliang Gui ◽

Qingpeng Li

Keyword(s):

Power Plants ◽

Thermal Power ◽

Construction Materials ◽

Ghg Emissions ◽

Energy Resource ◽

Clean Energy ◽

Hydropower Station ◽

Intergovernmental Panel ◽

Fossil Carbon ◽

Global Economic Growth

The development of clean energy is of great importance in alleviating both the energy crisis and environmental pollution resulting from rapid global economic growth. Hydroelectric generation is considered climate benign, as it neither requires fossil carbon to produce energy nor emits large amounts of greenhouse gases (GHG), unlike conventional energy generation techniques such as coal and oil power plants. However, dams and their associated reservoirs are not entirely GHG-neutral and their classification as a clean source of energy requires further investigation. This study evaluated the environmental impact of the Xiajiang hydropower station based on life cycle assessment (LCA) according to the 2006 Intergovernmental Panel on Climate Change (IPCC) guidelines, focusing specifically on GHG emissions after the submersion of the reservoir. Results reveal that although hydropower is not as clean as we thought, it is still an absolute “low emissions” power type in China. The amount of GHG emissions produced by this station is 3.72 million tons with an emissions coefficient of 32.63 g CO2eq/kWh. This figure is lower than that of thermal power, thus implying that hydropower is still a clean energy resource in China. Our recommendations to further minimize the environmental impacts of this station are the optimization of relevant structural designs, the utilization of new and improved construction materials, and the extension of farmland lifting technology.

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Energy Transition and Post-COVID World

World Economy and International Relations ◽

10.20542/0131-2227-2021-65-6-79-85 ◽

2021 ◽

Vol 65 (6) ◽

pp. 79-85

Author(s):

E. Telegina

Keyword(s):

Social Transformation ◽

Continuous Process ◽

Energy Resource ◽

Energy Transition ◽

Clean Energy ◽

Green Energy ◽

Digital Transformation ◽

Transport Infrastructure ◽

Electricity Production ◽

Digital World

Received 13.01.2021. The coronavirus pandemic has accelerated global economic, technological and social transformation, including the energy sector, and has given the impetus to energy transition from organic fuels to clean energy sources. Though oil will remain an important energy resource in the global energy balance, in the long run renewables will become the leading energy. The European Union and China are the leaders in implementation of energy transition strategies from fossil to clean energy. The transformation in the energy market has affected dramatically the relations between producers and consumers, who now actively determine the consumption trends (for example, green energy, electric vehicles, etc.). Distributed generation and blockchain in power industry enable the consumers to play an active part in the electricity production and distribution chains. Digital transformation and climate agenda are changing the structure of energy business from vertically integrated companies to knowledge-intensive networks. Investors almost unanimously vote for renewable energy. The largest oil and gas companies change their long-term strategies and transform into energy holdings with the prevailing share of renewables in the business structure. Hydrogen attracts particular attention as a promising energy source. The EU plans to develop hydrogen transport infrastructure. For its part, Russia has the ability to supply hydrogen to the European market through the existing gas pipelines. Coronacrisis accelerated the development of online services, artificial intelligence, and distant work. Education and telemedicine received a powerful impetus for further development. Еducation becomes continuous process in the digital world. New educational ecosystems in which skills and competencies are worked out on an interdisciplinary basis are formed. Digital transformation meets the expectations of the generation Z, which in the coming decades will become economically active and will dominate in social and economic agenda. Digitalization, adaptive nature-like technologies, environmentally friendly energy resources, flexible horizontal network between market participants are already a post-COVID reality.

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A Fuzzy Logic Controlled Single Axis Solar Tracking System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.787.893 ◽

2015 ◽

Vol 787 ◽

pp. 893-898

Author(s):

Suneetha Racharla ◽

K. Rajan ◽

K.R. Senthil Kumar

Keyword(s):

Fuzzy Controller ◽

Tracking System ◽

Renewable Energy Sources ◽

Energy Resource ◽

Clean Energy ◽

Energy Sources ◽

Pv Panel ◽

Solar Tracking ◽

Simulation Results ◽

Improved Performance

Recently renewable energy sources have gained much attention as a clean energy. But the main problem occurs with the varying nature with the day and season. Aim of this paper is to conserve the energy, of the natural resources. For solar energy resource, the output induced in the photovoltaic (PV) modules depends on solar radiation and temperature of the solar cells. To maximize the efficiency of the system it is necessary to track the path of sun in order to keep the panel perpendicular to the sun. This paper proposes the design and construction of a microcontroller-based solar panel tracking system. The fuzzy controller aims at maximizing the efficiency of PV panel by focusing the sunlight to incident perpendicularly to the panel. The system consists of a PV panel which can be operated with the help of DC motor, four LED sensors placed in different positions and a fuzzy controller which takes the input from sensors and gives output speed to motor. A prototype is fabricated to test the results and compared with the simulation results. The results show the improved performance by using a tracking system

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Geothermal resource exploration by using Numerical simulation and comprehensive geophysical method

10.21203/rs.3.rs-828808/v1 ◽

2021 ◽

Author(s):

Yang Yang ◽

Bin Xiong ◽

Sanxi Peng ◽

Ibrar Iqbal ◽

Tianyu Zhang

Keyword(s):

Detection Efficiency ◽

Energy Resource ◽

Clean Energy ◽

Shanxi Province ◽

Geothermal System ◽

Exploratory Research ◽

Geothermal Resource ◽

Geothermal Resources ◽

Transient Electromagnetic ◽

Resistivity Model

Abstract Geothermal energy is an important renewable clean energy resource with high development and usage potential. Geothermal resources, on the other hand, are buried deep below, and mining hazards are significant. Geophysical investigation is frequently required to determine the depth and location of geothermal resources. The Transient Electromagnetic Method (TEM) and the Controlled Source Audio Frequency Magnetotellurics (CSAMT) have the highest detection efficiency and accuracy of all electromagnetic exploration methods. This article initially explains the algorithm theory of the finite difference technique before establishing a simplified geothermal system resistivity model. Established on the simplified resistivity model, a simulation analysis of the ability of CSAMT and TEM to distinguish target body faults at different resistivities and dip angles was performed, and the effectiveness and difference of the two methods in detecting typical geothermal resource targets was verified. A complete exploratory research of CSAMT and TEM was conducted in Huairen County, Shuozhou City, Shanxi Province, China, based on theoretical analysis. Both approaches can reflect the geoelectric structure of the survey region, demonstrating the efficacy of the two methods in detecting genuine geothermal resources.

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AIRFOIL SHAPED STRUTS FOR VERTICAL AXIS WIND TURBINE

International Journal of Engineering Applied Sciences and Technology ◽

10.33564/ijeast.2021.v05i09.025 ◽

2021 ◽

Vol 5 (9) ◽

Author(s):

Samyak Jain ◽

Gautam Singh ◽

Varun Yadav ◽

Rahul Bisht

Keyword(s):

Aspect Ratio ◽

Wind Energy ◽

Wind Turbine ◽

Energy Resource ◽

Bending Moment ◽

Clean Energy ◽

Vertical Axis ◽

Vertical Axis Wind Turbine ◽

Aspect Ratios ◽

Cost Of Energy

Currently, many countries are racing towards switching to clean energy resource (1). Among the options available Solar and Wind are two viable options that are economically feasible. Each day a new development is helping in bringing down the cost of energy extracted from these sources. With currently available technologies, solar energy is almost as expensive as the energy generated from burning coal, whereas wind energy is still slightly expensive (2). However, wind energy could be made cheaper by the use of a vertical axis wind turbine (3). However, structure is a major factor that is holding back the development of VAWTs with better efficiency (4). The efficiency of a VAWT depends upon its aspect ratio. Aspect Ratio is the ratio of the height of the blade to the diameter of the turbine. The lower the aspect ratio, the higher the efficiency (5). However, decreasing the AR would mean either increasing the diameter of the turbine or the height of the blade. In either case, the bending moment would increase on the struts, that connect the blades to the shaft. In this paper we propose, struts with airfoil cross-section. This is because, the lift generated by airfoil struts acts as additional support for the blade, thus increasing our ability to work at lower aspect ratios.

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An integrated approach to assess both risk and impacts related with geo-resources exploration and exploitation

10.5194/egusphere-egu21-2216 ◽

2021 ◽

Author(s):

Maria Vittoria Gargiulo ◽

Alexander Garcia ◽

Ortensia Amoroso ◽

Paolo Capuano

Keyword(s):

Life Cycle ◽

Probabilistic Approach ◽

Energy Resource ◽

Clean Energy ◽

Integrated Approach ◽

The European Union ◽

Horizon 2020 ◽

Risk Sources ◽

New Perspective

To the welfare of both economy and communities, our society widely exploits geo-resources. Nevertheless, with benefits come risks and even impacts. Understanding how a given project intrinsically bares such risks and impacts is of critical importance for both industry and society. In particular, it is fundamental to distinguish between the specific impacts related to exploiting a given energy resource and those shared with the exploitation of other energy resources. In order to do so, it is useful to differentiate impacts in two categories: routine impacts &#8211; caused by ordinary routine operations, investigated by Life-cycle assessment with a deterministic approach &#8211; and risk impacts &#8211; caused by incidents due to system failure or external events, investigated by risk assessments with a probabilistic approach. The latter category is extremely interesting because it includes low probability/high consequences events, which may not be completely independent or unrelated, causing the most disastrous and unexpected damages. For this reason, it is becoming more and more crucial to develop a strategy to assess not only the single risks but also their possible interaction and to harmonize the result obtained for different risk sources. Of particular interest for this purpose is the Multi-Hazard/Multi-Risk Assessment.The aim of our work is to present an approach for a comprehensive analysis of impacts of geo-resource development projects. Routine operations as well as risks related to extreme events (as e.g.,seismic or meteorological) are linked using a Multi-Hazard Risk (MHR) approach built upon a Life-Cycle analysis (LCA). Given the complexity of the analysis, it is useful to adopt a multi-level approach: (a) an analysis of routine operations, (b) a qualitative identification of risk scenarios and (c) a quantitative multi-risk analysis performed adopting a bow-tie approach. In particular, after studying the two tools, i.e. LCA and MRA, we have implemented a protocol to interface them and to evaluate certain and potential impacts.The performance of the proposed approach is illustrated on a virtual site (based on a real one) for geothermal energy production. As a result, we analyse the outcome of the LCA, identify risk-bearing elements and events, to finally obtain harmonised risk matrices for the case study. Such approach, on the one hand, can be used to assess both deterministic and stochastic impacts, on the other hand, can also open new perspective in harmonizing them. Using the LCA outputs as inputs of the MRA can allow the analyst to focus on particular risk pathways that could otherwise seem less relevant but can open new perspective in the risk/impact evaluation of single elements, as we show in this case study.This work has been supported by S4CE ("Science for Clean Energy") project, funded from the European Union&#8217;s Horizon 2020 - R&I Framework Programme, under grant agreement No 764810 and by PRIN-MATISSE (20177EPPN2) project funded by Italian Ministry of Education and Research.

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