Abstract

Global warming concerns have motivated the study of new approaches that can decarbonize fossil fuels to produce clean fuels and commodities. A promising approach is solar-thermal methane pyrolysis to convert natural gas into clean hydrogen fuel and high-quality carbon product with virtually zero CO2 emissions by utilizing concentrated solar power. However, one of the challenges to continuous methane pyrolysis is deactivation of catalyst, when present, and establishing a facile means of extracting the valuable carbon product. In this work, a scalable route to continuous solar-thermal methane pyrolysis is presented that employs a roll-to-roll mode of operation. A high-flux solar simulator is used to mimic concentrated solar power and to allow operation at temperatures of approximately 1500 K, where methane rapidly decomposes onto the fibers of a porous carbon roll, collecting graphitic solid carbon and exhausting clean hydrogen fuel in addition to unconverted methane. The efficacy of the roll-to-roll approach for methane decomposition is investigated, and the technique is observed to be effective in achieving a continuous process. The roll-to roll mechanism maintains stable and relatively high methane conversion compared to a stationary substrate, where enhancement in methane conversion as high as 42% is observed. The quality of the carbon product obtained is generally high, with Raman D/G peak ratios near 0.5. This work therefore establishes a proven baseline for continuous production of graphitic carbon from solar pyrolysis.

Abstract

Injection of carbon dioxide into underground geological formations with proper structure is a common approach performed, such as, for geo-sequestration purposes. During this operation, host rock may then undergo a series of chemical and petrophysical alterations including dissolution and changes in pore structure. Subsequently, knowledge of potential variation in reservoir rock properties against these alterations is of great interest in planning for the geological storage of CO2. Amid these properties is the pore compressibility as a key factor in understanding of rock geomechanical behaviors. However, lab-based analysis of pore compressibility is a challenging procedure with ongoing issues. The present work provides a comparison between two different approaches for lab-based measurement of pore compressibility. The work compares usage of sister plugs and a single one to determine the effect of dissolution and applied pressure on pore compressibility in limestone samples exposed to supercritical CO2. For this purpose, core-flooding experiments with pore-water rich in CO2 were carried out to resemble real reservoir condition while the samples were undergone pore compressibility measurements with the above-mentioned approaches. In the end, it was revealed that using a single plug will provide more precise results compared to the sister plugs, however, attention must be paid to a number of critical parameters. In fact, injection and confining pressures are potential to cause pore closure, and so change the internal structure, during pre-injection pore compressibility measurement. Moreover, in case of using sister-plug approach, it is important to screen the samples based on their pore type and internal structure,

Abstract

The world is shifting towards cleaner energy resources from the high emission energy resources. Natural gas was proved to be one of the better fuels in overall comparison to conventional fuels with higher energy efficiency and lower emission. Natural gas has many challenges in order to store and transport it on a large and small scale. Liquefied natural gas (LNG) is an appropriate option available for large scale transportation of natural gas, while compressed natural gas (CNG) is used for small scale transportation. However, CNG has some disadvantages over the other available alternative way to store natural gas. Past research shows that CNG is not much economical for medium scale transportation. CNG also has inherent safety concerns due to transporting the highly pressurized gas on board. Natural gas hydrate (NGH) can be an optimistic source to store and transport natural gas.
Major studies available in the present world included the use of chemical additives to enhance gas hydrate growth. The chemical additives are divided into two groups: kinetic hydrate promotors (KHPs) and thermodynamic hydrate promotors (THPs). KHPs are chemical additives that can reduce the interface mass transfer limitation by their inherent properties for reducing surface tension using micellization or other physical properties. While THPs are the chemical additives that can shift the phase equilibria requirement of gas hydrate formation by taking part in the process. This study represents alternate chemical additives that can work better than conventional surfactant-based KHPs. Sodium dodecyl sulfate (SDS) is a well-known KHP that has been used to study gas hydrate formation. SDS and other surfactants have the inherent disadvantage of very high foam generation, which can create trouble in the scale-up of the methane gas hydrate technology. Therefore, the need for an hour is to find an inexpensive, biodegradable, efficient, and reliable chemical additive with the added advantage of no foam generation.
The current study demonstrates the use of sodium salts of pnictogen oxides (SPO) to explore methane gas hydrate formation. The performance of the SPO is up to the mark of SDS in order to enhance the gas hydrate formation. There was no foam generation while using the SPO in pure water, and due to their inorganic nature, they can easily dissolve in pure water. The current research shows the result of using 0.01 mole % SPO to form methane gas hydrate, which can open the opportunity for the scale-up by lower utilization of the additives. The morphology of gas hydrate can also be understood with the help of photos taken at a fixed, consecutive interval of time. Artificial intelligence based deep learning approach was utilized to validate the experimental results obtained from this research. An artificial neural network (ANN) was used to develop the model in Matlab R21. The model predicted results were perfectly aligned with the experimental results, which shows the application of this model in future chemical additive selection. The linear regression of the experimental and model predicted results have an R2 value of greater than 0.9, which can explain the reliability of the model. Overall, SPO was proved to be a better alternative to conventional KHPs by using experimental and modeling study.

Abstract

Sustainable Development of energy is a problem that every country in the world needs to consider, which is a huge challenge to the adjustment of energy structure of every country. In China, hydropower is a high-quality and renewable energy source, and the key to the implementation of the Paris Agreement and the implementation of China’s emission reduction commitments lies in China’s hydropower. At present, the application of UNFC in the field of water energy resources is still in the preliminary stage, the research group on water energy resources established by the United Nations is in the research and development stage, and there are no examples of application in the field of water energy resources on its website. In this paper, we collected the data of China’s hydropower projects, which have been put into operation and are being surveyed and exploited, is preliminarily based on the core theory of UNFC, through the actual reference indicators of some projects, the impact of the impact has been identified, pros and cons of such information, classified assessment. On the basis of the 2019 revised UNFC, the classification and evaluation system is analyzed and summarized in the light of the hydropower resources utilization projects that have been put into operation and are being surveyed and developed in China. The basic three-dimensional framework of UNFC and some applicable terms are retained in the analysis process, in combination with the actual situation of China’s projects, the inappropriate parts are modified to adapt to the application of China’s hydropower resources utilization projects. The purpose of this paper is to find out the key points that need to be paid attention to when using the UNFC, and how to evaluate the project reasonably, so that it can be used as an evaluation tool to evaluate the water energy resources utilization projects .As a decision-making tool that has been put into operation, it can provide decision-making and reference guidance for hydropower resource utilization projects under research and development and projects to be developed in the future, and provide a certain reference for countries to achieve their goals. it can provide decision-making and reference guidance for the water energy resources utilization projects being investigated and developed and the future projects to be developed, it can provide some reference for countries to achieve the goal of sustainable, environment-friendly, carbon-neutral and efficient development.

Abstract

This study investigates the effects of firm characteristics on firms’ decisions to invest in renewable energy. Using the unique dataset of annual firm-level data from around 300 firms from the People’s Republic of China that invested in renewable energy projects in the People Republic of China during the period 2015-2020 from Bloomberg Terminal, Bloomberg New Energy Finance, and S&P Capital IQ pro, our results demonstrate which firm characteristics affect firm decisions to invest in renewable energy.

Abstract

Energy storage and water desalination are two fields where Egypt is intensively investing in to plan for the current and future energy and water demands as well as commit to its sustainability targets, Integrated Pumped hydro Reverse osmosis System “IPHROS” is a system that combines both water production and energy storage, its operating schedule in studied in multiple scenarios that represent current status and future trends. The system is modeled as an unconstrained price taker, this revenue scheme starts yielding a positive re-turn on investments when higher renewables penetration are added to the grid but also in-creases the overall grid emissions, the IPHROS was also modeled in an off-grid scenario to provide energy and fresh water to a hydrogen electrolyzer, which proved to be the most profitable scenario for IPRHOS.

Abstract

We discuss the role OPEC producers can play in the transition to a net-zero future through shifting their financial investment capacity into alternative energy sources. OPEC producers, especially Saudi Arabia, could establish a significant advantage in becoming a dominant player in the hydrogen market.

Abstract

The effects of carbon fuel consumption on the environment have stimulated development of a ‘net-zero’ energy measurement in buildings envelope for sustainable buildings a net-zero energy is key to reducing energy use and saving money .For several decades, low-income citizens in Moroccan cities have been suffering from thermal inequality, energy poverty and thermal comfort constraints.The article presents the integrated the mechanical solar ventilation and phase change materials into the building envelope using the simulation software of the thermal behavior in dynamic regime TRNSYS, this project aims at the design of a single- family house whose energy balance over one year of operation. In particular when the air temperature is close to the melting temperature 22 °C . A global building model consisting of a building envelope modeled and simulated in TRNSYS and EnergyPlus and the modeled exchanger Mechanic solar ventilation air/PCM fan system is simulated under climate (CASABLANCA NOUSSEUR).The energy consumption related to the specific uses of electricity is taken into account in the annual energy balance. The results show that the Mechanical solar ventilation with the phase change materials (PCM+MSV) reduces the operating temperature of the house significantly and relative humidity and maintain the demand energy from HVAC system. Indeed, the Mechanical solar ventilation has decreased its average operating temperature by about 2.7°C-3°C and created the fresh and comfort space.

Abstract

Metal foam has excellent characteristics to improve the performance of heat transfer in the latent thermal energy storage. However, as for horizontal heat storage tube, the refractory problem at the bottom leads to reduce heat storage efficiency. In this Manuscript, we cut off the bottom of horizontal tubes with different ratios to explore the influence on heat storage efficiency. Through the method of experiment and numerical simulation comparison, the melting fraction, melting interface and velocity field are obtained. The results showed that the smaller the bottom cross-cut ratio, the faster the melting rate. When the bottom cross-cut ratio is 0.6, the complete melting time is the least, 1120 s, which is 18.841 % shorter than that of the round tube.

Abstract

In previous studies on thermal performance of solid-liquid phase change thermal energy storage (TES), it could be found that the lower phase change material (PCM) of TES was difficult to melt due to the influence of natural convection. Therefore, many scholars improved the overall thermal performance by enhancing the heat transfer in the lower region, increasing the distribution of the lower fins, increasing the length of the lower fins, or changing the porosity of the lower metal foam to improve the lower heat transfer. However, it had not been found that by changing the ratio of the upper and lower PCM to improve the heat storage performance. Therefore, this paper designed ten cases to study the effect of different ratios of the upper and lower PCM on the heat storage performance and finally found that the case 2 performed best, and the full melting time is 17240 s, reduced 39.05% compared with 28290 s of case 6.