Energy Science & Engineering最新文献

Hot water injection has been a simple and promising method of thermally stimulating the extraction of hydrates, which promotes the dissociation of natural gas hydrates and improves gas production. However, the temperature region influenced by injecting hot water requires further research and evaluation. In this study, a computational model of the temperature field in the hydrate reservoir during hot water injection with the finite volume method, considering coupled gas–liquid two-phase flow, heat conduction, and hydrate dissociation, was developed. The model focuses on hot water injection vertical wells completed with slotted liners in the Shenhu Sea area hydrate reservoir, which can consider the heterogeneity of porosity, permeability, and saturation. It also analyzes the effects of injection volume, injection rate, hot water temperature, and other factors on the variations in temperature and pressure distribution. The results indicate that selecting the appropriate injection volume, the temperature of hot water, and the injection rate can promote hydrate decomposition and expand the range of heat stimulation reservoir temperature. Reservoir heterogeneity leads to heterogeneity of the hydrate dissociation front and temperature influence range, and the influence range of heat stimulation is larger than homogeneous reservoir.

The use of static drill-rooted energy piles in deep soft soil foundations causes thermal exchange between the piles and the surrounding soil, resulting in excess pore pressure and consolidation settlement in the soft soil layer around the piles, which affects the long-term deformation of the site. To investigate the impact of the operation of this novel energy pile on the consolidation of the soil around the pile, a simulation analysis was conducted using the ABAQUS software to assess the soil temperature, pore pressure, and consolidation settlement around the static drill rooted energy pile group under a 120-day heating and cooling cycle. The research findings indicated that the temperature change decreased as the distance between the soil and the pile increased, resulting in less thermal consolidation settlement and pore pressure variations. Heating conditions (ΔT = 18.7°C) resulted in a 17°C increase in the soil temperature below the center of the pile group, with temperature changes becoming negligible beyond 8D. The maximum pore pressure variations in the soil occurred at 2D and 6D distances from the pile, with values of 1.24 and 1.12 kPa, respectively. Under heating conditions, the surface settlement at a 2D distance from the pile group was 6.19 mm, which increased to about 10 mm under heating–cooling cycles. These research findings provide a foundation for analyzing the environmental impact of novel energy piles in coastal areas.

To address the problems of the large deformation of surrounding rock, failure of support, and even roof fall under the influence of severe mining in the return airway of the panel I0116³06 in Mindong No.1 Coal Mine, the fracture evolution characteristics and deformation law of the roadway composite roof were investigated through numerical simulation, theoretical analysis, and on-site detection. With the continuous evolution of the magnitude and direction of the main stress in the surrounding rock of the mining roadway with a composite roof, the following observations were made: first, plastic failure occurred in the shallow area; second, because the undamaged hard coal seam cannot block the expansion of the plastic zone, the plastic zone crosses the undamaged hard coal seam and expands into the deep part. The strong deformation pressure caused by the expanding plastic failure of the deep interlayer leads to tensile fracture failure at the middle of the lower part of the undamaged hard coal seam, and to overall instability. According to the evolutionary pattern of the plastic zone in the composite roof of the mining roadway, the multi-level coupling support technology (MCST) focusing on the fracture morphology of the composite roof is applied to the test roadway. The field monitoring results reveal that the application effect is satisfactory.

Alternative fuels for diesel engines are essential to reduce greenhouse gas emissions, improve energy security by reducing dependence on petroleum, and minimise air pollution by using cleaner-burning fuels. This study investigates the environmental effects of utilising biodiesel derived from waste mosambi peel oil as a sustainable fuel alternative for common rail direct injection diesel engines. Butylated hydroxytoluene (BHT) nanoparticles were employed as an ignition enhancer to mitigate the emissions. The test fuels comprised conventional diesel, mosambi waste peel biodiesel (MWPB), and MWPB blends with BHT [MWPB + 10-µm BHT 10 ppm (parts per million) and MWPB + 20-µm BHT 10 ppm]. The test results indicated that the MWPB + 10-µm BHT 10 ppm blend significantly reduced primary pollutants, with smoke, hydrocarbon and carbon monoxide emissions by 42.3%, 38.09% and 61.71%, respectively, compared to pure diesel. Utilising MWPB resulted in a substantial 14.67% increase in nitrogen oxide emissions at maximum brake power. This study emphasises the potential of waste-derived biodiesel to substantially minimise environmental emissions, encouraging a more sustainable energy future.

Bend pipe is a commonly used part of long-distance pipelines. It is very important to study the flow law of hydrate particles in the bend pipe to optimize pipeline design. In addition, the efficiency and safety of pipeline gas transmission will be improved. The flow of hydrate particles in the bend pipe is the research object of this paper, and the short twist tape is used as the spiral device, and numerical simulation methods are used to study the effects of the bend angle and the twist rate on the velocity distribution, turbulence intensity distribution, wall shear, particle movement and pressure drop distribution of the spiral flow carrying hydrate particles. The results show that as the twist rate of the twist tape is smaller, and the spiral flow is stronger, the fluid can generate a larger tangential velocity when flowing through the bend. The maximum speed at the section closest to the entrance is 28% higher than at the section furthest. Maximum tangential speed increased by 2 times. When the angle of the bend is larger, and velocity is more conducive to maintaining the spiral flow pattern of the particles, it is also more conducive to maintain. However, the twist rate is smaller, and the resistance is greater, then the pressure drop is greater, and the resistance coefficient of the bend pipe section is greater. With the increase of torsion, the pressure drop decreased by 52%. When the angle of the bend pipe section becomes smaller, it increases the collision frequency between the pipe wall and the natural gas. Unit pressure drop loss increased by 13%. When the angle is smaller, the change in the direction of the velocity of the particles will be more violent, and the pressure drop is larger, and the drag coefficient is larger. In the same section, the maximum turbulence intensity is about twice the minimum.

Minimizing the detrimental effects of global warming and pollution from fossil fuel consumption is essential to meet the growing demand for energy and fresh water, making it imperative to adopt renewable energy alternatives. The integration of solar energy and biomass in hybrid renewable energy systems will grow in importance. The proposed study introduces a new design that facilitates the simultaneous production of power, biogas, and fresh water in a continuous process. The present research aims to tackle the challenge of utilizing multiple renewable energy sources, such as solar and biomass, to generate power, fuel, and fresh water. To achieve this, a 4-stage multi-effect desalination system will be employed for desalinating seawater. This paper discusses combining hybrid solar and biomass feedstocks to address the challenge of maintaining consistent energy production in renewable solar power plants at night, when there is no sunlight. The challenge at hand involves assessing various factors using ASPEN Plus software, such as solar heat transfer fluid (SHTF), sewage sludge flowrates, biogas production, output waste stream of gasification reactor, power generation, and freshwater production. Additionally, the payback period for this project is approximately 4.8 years, with a net present value (NPV) of around 560 million dollars. By performing a sensitivity analysis, the viability of the designed process and the quality of the resulting products were effectively demonstrated. From the gasification process, an impressive 76.8586 tons per hour of syngas, composed of carbon monoxide and hydrogen, was generated. Additionally, the power output of the system reached 34.547 MW, while simultaneously producing approximately 783 m³/h of fresh water. Due to efficient energy recovery throughout the entire process, only 25 MW of solar power was required. Despite efforts, fresh water production was only operating at a 50% productivity level. To supply the required solar energy during daylight hours, a total of 38,908 square meters of Parabolic trough collector (PTC) was necessary. According to the environmental analysis, the primary concern is the detrimental effect of pollution on human health. Solar collectors and sea water desalination units account for over 95% of the pollution. The revelation showed that combining solar and biomass energy resources could provide a sustainable solution to meet the rising demand for fresh water, electricity, and fuel.

To reduce carbon emissions of an integrated energy system (IES), and decrease curtailment of wind and solar energy due to the “power determined by heat” characteristics of combined heat and power (CHP) units, this paper proposes a low-carbon and economic optimal scheduling model of an IES that considers solar thermal coupled with CHP. First, to alleviate the coupling of heat and electric power, a solar thermal collector (STC)-CHP unit model is developed by integrating an STC unit with the traditional CHP unit in the IES. In addition, hydrogen energy utilization equipment, including hydrogen fuel cell (HFC), hydrogen storage (HS), is introduced based on the traditional power-to-gas (P2G) process, to fully exploit the value of hydrogen. Meanwhile, the carbon capture system (CCS) is considered in the IES to reduce the carbon emission. Next, a low-carbon economic dispatch model of the STC-CHP-P2G-CCS coupled IES is established considering the reward and punishment ladder-type carbon trading (RPLCT) mechanism, aiming to minimize economic costs. The proposed model is solved by programming the CPLEX solver through the YALMIP toolbox. Finally, two categories of scenarios simulation are set up to evaluate the proposed IES and its dispatch strategy. Results show that the total daily operating cost of the proposed system amounts to 8.6525 million RMB, marking a significant reduction of 8.2695 million RMB compared to the basic system. This substantial saving not only covers but also exceeds the daily investment cost of 1.8561 million RMB required for the new equipment, demonstrating a certain level of economic viability. In addition, the system achieves a 100% renewable energy accommodation rate, and carbon emissions are reduced by 2596.3 tons by incorporating the RPLCT mechanism, achieving negative carbon emissions.

Bolt support mechanisms represent a key technique to support the surrounding rock in coal mines. In deep rock engineering applications, the bolt-supported structure of the surrounding rock of a deep roadway under high bearing stress may fail under dynamic loads such as those of blasting vibrations and earthquake motion. In this study, dynamic uniaxial compression tests were conducted on steel bar reinforced rock to investigate the rockbolt performance under dynamic loading. The deformation of the specimen surface and rockbolt was recorded during the test. The strengths and failure modes of the bolted rock samples were investigated. The results show that the bolt and rock deform asynchronously when the bolted specimen is subjected to a dynamic load, and the time of the asynchronous deformation of the specimens with different bolt angles is considerably different. When the stress wave acts along the direction of the bolt, it is more likely to cause the failure of the bolted specimen. Anchorage agents should be employed to realize the synchronous deformation of the bolt and rock mass. The slip and dislocation of the anchorage agent/rock surface and anchorage agent/bolt interface are the key factors influencing the failure of bolted specimens. The influence of a dynamic stress wave on the surrounding rock support structure of a deep roadway can be effectively reduced by improving the antisliding characteristics of the anchoring agent and increasing the bolt density. The research results can provide theoretical guidance and serve as a reference to realize the reinforcement engineering of underground permanent chambers and roadways.

CCUS-enhanced oil recovery (EOR) technology relies on the unique properties of CO₂ gas in the process of efficient oil displacement while achieving effective storage, which has become one of the most economical and effective measures for reducing greenhouse gas emissions in today's society and is important for helping to realize the global strategic goal of carbon neutrality. Based on previous research results, this review presents the oil displacement and geological storage mechanisms of CO₂ in micropores in the oil and gas fields, and summarizes their respective influencing factors. At the same time, it also summarizes the current research status of CO₂-EOR and geological storage from the perspectives of laboratory experiments and numerical simulations. Moreover, it provides a detailed overview of four key technologies namely, miscibility improvement, swept volume expansion, storage potential assessment and storage safety monitoring, and their field applications. On this basis, this review compares the development status of field applications in Developed Countries and China, analyzes the problems of CCUS-EOR technology in theoretical research, technology research and development and project industrialization, and points out the future development directions. Results are presented that research on CO₂-EOR and geological storage in Developed Countries such as the United States started early and developed rapidly. A relatively complete industrial chain system has been formed, and the scale and number of CCUS-EOR projects are far ahead those in China. In China, relevant research started relatively late and developed slowly at the early stage. In recent years, due to the notable attention given to climate change and carbon storage, development efforts in China have gradually intensified. At present, there are more than 20 large-scale CCUS-EOR demonstration projects in operation, which are preliminarily ready for industrial promotion. Notably, the world has continued to increase its attention to CCUS-EOR projects based on national conditions, further improving policy guidance mechanisms, strengthening research and development efforts, promoting the construction of the full-process industry chain, achieving large-scale and refined development, and providing theoretical guidance and technical support for realizing the strategic goal of carbon neutrality.

Nima Basin, as a typical Tethys area, is a Cenozoic oil-bearing basin in the middle of Qinghai-Tibet Plateau, which is expected to become an important target for petroleum exploration. The main controlling factors and models of organic matter enrichment are not yet clear. To identify the organic geochemical characteristics of high-quality source rocks and the main controlling factors of their formation, this study analyzes the paleoclimate and paleo-salinity indexes based on the analysis of the major and trace elements through systematic sampling of the muddy sediments of Niubao Formation in Well Shuangdi 1, Cebuco Depression. The results show that the organic matter of the E_1-2n source rocks in Nima Basin is differentially enriched, which shows that the organic matter of the middle E_1-2n source rocks is more enriched than that of the upper E_1-2n source rocks. Hydrocarbon source rocks of the middle E_1-2n are mainly of type I organic matter, while those of the upper E_1-2n are mainly of type Ⅱ₁ organic matter, both of which are in the mature stage. Organic matter enrichment is primarily governed by a combination of climate and redox conditions, with humid climate and reducing environments emerging as the dominant factors, whereas salinity exerts a lesser influence. On the one hand, this study can supplement the accumulation mechanism of organic matter in the Tethys domain in Asia; on the other hand, it will fill the gap in the geological research of Nima Basin, contributing to the prediction and exploration of oil and gas resources in the Nima Basin.