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In a general high-dimensional process, a large number of process parameters or quality characteristics is found to be featured through their dependencies and relevance. The features that have similar characteristics or behaviors in the process operation can be categorized into multiple groups. Thus, when a few quality characteristics in the process change, it is highly probable that the process shift would have occurred in a few relevant groups. Recently, several advanced statistical process control techniques are developed to monitor the changes in high-dimensional processes under sparsity. However, monitoring schemes that utilize the grouped pattern of the quality characteristics are sparse. This paper proposes a new method to monitor the high-dimensional process when the grouped structure of the process data is observed. The proposed method identifies the potentially changed groups and individual variables within the groups based on a modified sparse group LASSO (MSGL) model. Then, a monitoring statistic is obtained using MSGL-based likelihood function to test abnormality of the process. Extensive numerical studies are conducted to demonstrate the effectiveness and efficiency of the proposed method. In addition, a real-life application of a liquefied natural gas process is presented to illustrate the proposed method. [ABSTRACT FROM AUTHOR]

To achieve net-zero objectives, the expansion of renewable energy sources is anticipated to be accompanied by an increased use of carbon-free fuels, such as hydrogen. Internationally, there are proposals for transporting hydrogen by synthesizing it into carriers like ammonia or Liquid Organic Hydrogen Carriers (LOHCs). However, considering the energy consumption required for hydrogenation and dehydrogenation processes and the need for high-purity hydrogen production, the development of liquid hydrogen transportation technologies is becoming increasingly important. Liquid hydrogen, with a density approximately one-sixth that of liquid natural gas and a boiling point roughly 90 K lower, poses significant challenges in suppressing and managing boil-off gas during transportation. Slush hydrogen, a mixture of liquid and solid phases, offers potential benefits. with an approximate 15% increase in density and an 18% increase in thermal capacity compared to liquid hydrogen. The latent heat of fusion of solid hydrogen effectively suppresses boil-off gas (BOG), and the increased density can reduce transportation costs. This study experimentally validated the long-duration storage and transportation concept of slush hydrogen by adapting NASA's (National Aeronautics and Space Administration) proposed IRAS (Integrated Refrigeration and Storage) technology for compact and mobile tanks. Slush hydrogen was successfully produced by reaching the triple point of hydrogen, resulting in a composition of 47% solid and 53% liquid, with a density of approximately 80.9 kg/m3. Most importantly, methodologies were presented to observe and measure whether the hydrogen was indeed in the slush state and to determine its density. Additionally, CFD (Computational Fluid Dynamics) analysis was performed using solid hydrogen properties, and the results were compared with experimental values. Notably, this analytical technique can be utilized in designing large-capacity tanks for storing slush hydrogen. [ABSTRACT FROM AUTHOR]

This study was aimed at improving the energy efficiency of the distribution of liquefied natural gas (LNG) as shipping fuel in the southern Baltic Sea. The objective of this study was to determine the demand for LNG for maritime shipping by analyzing the distribution of the resource from the water side (ship-to-ship). LNG was chosen due to the location of the LNG terminal in Świnoujście within the analyzed water area, where a problem has arisen in the southern part of the Baltic Sea regarding fuel supply for vessels due to the lack of developed infrastructure along the coast. An analysis was conducted to optimize the size of the LNG fleet and infrastructure facilities. Seeking compliance with Annex VI to the MARPOL 73/78 Convention, adopted by the International Maritime Organization (IMO), shipowners see potential in the switch from conventional fuels to LNG. As one of the alternative solutions, it will contribute to reducing harmful emissions. Determination of the LNG distribution volume requires the identification of LNG storage facility locations, specifying the number of LNG-powered ships (broken down by type) and the number of LNG bunkering ships. The first part of this study contains a detailed analysis of the number of sea-going ships that provide services in the southern part of the Baltic Sea and the world's number of LNG bunkering ships. The database contains a set of the characteristics required to determine the optimal demand for LNG, where LNG bunkering vessels are capable of supplying fuel within the shortest possible time and covering the shortest possible distance to LNG-powered ships. The characteristics include the type of ship, requested LNG volume, the speed of LNG bunkering ships, the distance between LNG facilities, and the loading rate (the volume of fuel received per time unit). Based on the collected data, the volume of LNG distribution was determined using MATLAB R2019a software. The remainder of this study contains a description of the conducted research and results of an analysis of the traffic density in the Baltic Sea. The results were obtained on the basis of data from the Statistical Yearbook of Maritime Economy and IALA IWRAP Mk2 2020 software. The number of LNG-powered ships and number of LNG bunkering ships were specified, and the demand for LNG for the area under analysis was determined. [ABSTRACT FROM AUTHOR]

Cryogenics is the science and technology of very low temperatures, typically below 120 K. The most common applications are liquified natural gas carriers, ground-based tanks, and propellant tanks for space launchers. A crucial aspect of cryogenic technology is effective insulation to minimise boil-off from storage tanks and prevent frost build-up. Rigid closed-cell foams are prominent in various applications, including cryogenic insulation, due to their balance between thermal and mechanical properties. Polyurethane (PU) foam is widely used for internal insulation in cryogenic tanks, providing durability under thermal shocks and operational loads. External insulation, used in liquified natural gas carriers and ground-based tanks, generally demands less compressive strength and can utilise lower-density foams. The evolution of cryogenic insulation materials has seen the incorporation of environmentally friendly blowing agents and bio-based polyols to enhance sustainability. Fourth-generation physical blowing agents, such as HFO-1233zd(E) and HFO-1336mzz(Z), offer low global warming potential and improved thermal conductivity. Additionally, bio-based polyols from renewable resources like different natural oils and recycled polyethylene terephthalate (PET) are being integrated into rigid PU foams, showing promising properties for cryogenic applications. Research continues to optimise these materials for better mechanical performance and environmental impact. [ABSTRACT FROM AUTHOR]

Floating production storage and offloading unit (FPSO) is an offshore vessel, producing, storing natural gas or crude oil, prior to oil shuttle tanker transport. The equivalent of natural gas is known as floating liquefied natural gas (FLNG). Robust prediction of the extreme mooring hawser tensions, during FPSO operations, is an important design and engineering reliability and safety concern. Excessive mooring hawser tensions may occur during certain types of offloading operations, posing potential operational risks. In this study, ANSYS-AQWA-software package has been used to model vessel dynamics, subjected to hydrodynamic wave loads, acting on FPSO or liquefied natural gas (LNG) vessel, under actual in situ environmental conditions. Experimental validation of the numerical results has been briefly discussed as well. This study presents novel multi-dimensional reliability method, based on Monte Carlo simulations (or alternatively on measurements). Proposed methodology provides accurate failure or damage risks assessment, utilizing available underlying dataset efficiently. Described approach may be well utilized at the vessel design stage, while selecting optimal vessel's parameters, minimizing potential FPSO mooring hawser tensions. The aim of this study was to benchmark state of the art Gaidai reliability method, proposed recently; this novel methodology opens up the possibility to predict simply and efficiently failure or damage risks for non-linear multi-dimensional dynamic offshore energy system as a whole. Key advantage of the suggested methodology is its multi-dimensionality (with unlimited number of system dimensions/components/processes, all having different physical dimensions), while classic reliability methods typically are not covering dimensions higher than two. [ABSTRACT FROM AUTHOR]

• A high cooling capacity Stirling cryocooler is developed to liquefy boil-off gas. • The relative Carnot efficiency of the cryocooler reaches 33.28% at 77 K. • The cryocooler is installed in the skid-mounted BOG liquefaction system. • The system produces 27.3 L/h LNG and shows a great application potential. Natural gas is a cost-effective energy supply for the development of low-carbon economy and environmental protection worldwide. Despite the environmentally friendly properties of natural gas, methane is a potent greenhouse gas. Therefore, efficiently recovering the boil-off methane gas (BOG) generated from liquefied natural gas (LNG) devices is becoming a pressing problem involving both the economy and the environment. The Stirling cryocooler is a promising technology in dealing with BOG. This technology has superior characteristics, including large cooling capacity, high efficiency, compact configuration, and flexible operating characteristics. In the study, a high cooling capacity Stirling cryocooler was developed. The influences of the regenerator on the cryocooler were studied. The refrigeration performance and the operating characteristics were systematically analyzed. A cooling power of 1050 W at 77 K with a relative Carnot efficiency of 33.28 % was achieved. Accordingly, the cryocooler outperforms the reported Stirling-type cryocoolers in terms of overall performance. A BOG liquefaction system based on the cryocooler was installed in an LNG refueling station. On-site test results demonstrated that the system can produce 27.3 L/h LNG with a power consumption of 14.5 kW. The present research lays a good foundation for future optimizations and applications of the cryocooler in liquefying BOG. [ABSTRACT FROM AUTHOR]

Highlights: Most of the studies on oil tanks have focused on the analysis of deformation and settlement, and more research needs to be done on crack extraction from external LNG tanks. Oil tanks are more sensitive to temperature due to the lower temperature inside the tank. Using infrared images as a dataset for crack recognition can identify cracks that the naked eye cannot see, and a convolutional neural network that introduces a channel attention mechanism is used for crack recognition with a recognition accuracy of 85.9%. The automatic extraction of three-dimensional (3D) crack point clouds using depth images is novel and accurate, with an accuracy of about 97.6%. The precise detection and ongoing surveillance of surface fractures on exterior LNG storage tanks are crucial in guaranteeing the secure transit and storage of natural gas. Undetected fractures have the potential to result in the release of liquefied natural gas (LNG), hence presenting a significant risk to both public health and the environment. This paper presents a novel approach for crack identification, which involves the integration of thermal infrared images and point clouds derived from close-range images captured by unmanned aerial vehicles (UAVs). The aim of this approach is to overcome the limitations of conventional manual detection methods, namely in terms of efficiency and safety concerns. The primary approach for acquiring two-dimensional photographs of the tank surface is the utilization of infrared technology to generate an infrared dataset capturing the presence of fractures on the storage tanks' exterior. The utilization of the attention mechanism convolutional neural network is employed during the process of model training. The UAV close-range photos were utilized in close-range photogrammetry to generate an accurate point cloud model. This was achieved by incorporating control point coordinates and matching feature points. The infrared photos that were discovered were subsequently matched with this particular model. The 3D model that was officially was employed as a point of reference on the unfolded two-dimensional (2D) plane. To construct the depth image, a least-squares approach of least-column fitting was utilized. In order to validate the accuracy of the automated extraction process, a manual crack extraction was conducted on the original close-range image point cloud of the tank exterior. The results indicated that the extracted cracks exhibited an accuracy level of around 97.6%. The experimental findings demonstrate that the process of crack extraction exhibits a high level of accuracy, hence presenting numerous possible applications in the realms of maintenance management and intelligent monitoring. The utilization of this technology is appropriate for the purpose of monitoring the thermal conditions and structural soundness of LNG storage tanks. [ABSTRACT FROM AUTHOR]

When loading liquefied natural gas (LNG) onto a dual-fuel LNG container ship fuelled by LNG, there is a considerable temperature difference between LNG and the fuel tank at room temperature. The current solution is to pre-cool the tank with LNG through a spray line but the cooling process, if not correctly handled, can result in excessive cooling rates and Boil-Off Gas (BOG), which can expose the tank to increased temperature stress and gas pressure. Therefore, this paper takes the Mark III fuel tank of a specific type of LNG container ship as the object and realises a real-time predictive control system by writing a UDF (User Defined Function) to simulate and analyse the influence of LNG spray rate on the change of cooling effect, cooling time and cooling cost under the unidirectional LNG spray cooling mode. Compared with the results of the fuel tank gas experiment, the deviation of numerical model simulation results is less than 5%. Under the same cooling rate, the real-time control scheme can achieve a more uniform cooling rate and reduce the total LNG consumption by 25%. With the increase in LNG cooling rate, the cooling time, LNG usage, and the total BOG exhaust volume all decrease; however, the decreased range gradually decreases as well. The results of this paper provide parameters and suggestions for optimising and improving the LNG fuel tank cooling monitoring and control system. [ABSTRACT FROM AUTHOR]

This study analyzed the mechanical properties of reinforced concrete flexural and axial-tension members at low temperatures ranging from 273.15 to 108.15 K based on experimental and theoretical analyses. Special test chambers were used to separately apply mechanical forces and low temperatures to the test members. The steel strain caused by the mechanical and thermal restraint forces was obtained using the self-compensation test method. The effects of low temperatures on the tensile and flexural stiffness behaviors of reinforced concrete beams, as well as the internal forces generated because of the different linear expansion coefficients of concrete and steel at low temperatures, were analyzed. Analytical models were developed to predict the restraint stress corresponding to different temperatures. The accuracy of the analytical models was verified using the test results. The results show that the deformation stiffness of both flexural and axial-tension members increases linearly with decreasing temperature. The difference between the thermal deformation of concrete and steel bars becomes more considerable as the temperature decreases, resulting in nonnegligible restraint stress in the steel bars. The study can provide a basis for the design of structures in service at low and ultralow temperatures, such as liquefied natural gas storage tank structures. Practical Applications: Liquefied natural gas (LNG) is primarily composed of methane. After extraction from gas fields, it goes through a purification process; thereafter, it is subjected to a series of ultralow-temperature liquefaction steps and transported through specialized LNG carriers. LNG has extensive applications in various aspects of daily life, including energy supply, transportation, industrial use, and power generation. Compared with traditional fuels, LNG offers higher efficiency and environmental benefits. Nonetheless, optimizing the design of LNG storage facilities presents several technical challenges. Presently, reinforced concrete is the predominant material used in the construction of LNG storage facilities. To fully exploit the advantages of concrete structures in ultralow-temperature environments and reduce construction costs, comprehensive studies on the performance of concrete under such extreme conditions are crucial. This study is of immense scientific value and offers promising prospects for practical applications. [ABSTRACT FROM AUTHOR]

Air separation processes are time‐consuming and energy‐intensive. Most of the energy used in air separation unit (ASU) is used for air compression. During the air compression process, some energy is lost, which is converted into waste heat. This wasted energy is used to warm liquefied natural gas (LNG). At some point, LNG ships will dock at an LNG regasification facility. Here, LNG is converted back to gas and supplied to the distribution and transmission systems. During the regasification process, cryogenic LNG has a huge opportunity for cold energy recovery. An innovative air separation process that is integrated with the cold utilization of LNG is presented in this study along with a thorough conceptual design and analysis. The results of this study show that producing high‐purity oxygen and nitrogen, respectively, requires 0.28 kWh kg−1 and 0.06 kWh kg−1 of specific energies. Prior to integration with cold utilization of natural gas, 25 141.6 kW is needed for air compression. However, following integration, 10 554.6 kW of energy is needed, resulting in a 58.01 % energy savings. Exergy destruction as well as efficiency have been calculated for the primary components of the system. Sensitivity analysis is carried out to examine the effects of LNG streams on important parameters. In conclusion, a cryogenic ASU is integrated with an LNG‐direct expansion cycle‐organic Rankine cycle power cycle to supply the necessary power for operation and reduce extraneous power inputs. Overall, this integrated approach increases efficiency, lowers costs, benefits the environment, allows for flexibility and adaptability, and raises system dependability. [ABSTRACT FROM AUTHOR]

This article discusses the concept of heat integration in distillation columns using side reboilers. It explains how side reboilers can supply a portion of the thermal duty required for distillation, using a lower-cost hot utility compared to the bottom reboiler. The article focuses on a graphical method based on pinch analysis to determine the thermal duty and column position for side reboilers, using a case study of a demethanizer column in a natural gas liquid recovery plant. The article is aimed at process engineers involved in conceptual design and optimization studies. Additionally, the article discusses the optimization of a simulation model for ethane recovery in natural gas liquids production, using parameters such as vapor split, column operating pressure, and inlet gas temperature. The simulation results show a 93% ethane recovery in the NGL product. The article also introduces the concept of a grand composite curve (GCC) and its application in heat integration for distillation columns, explaining how side reboilers can be incorporated into the simulation model to optimize heat integration. However, it should be noted that the method requires a trial-and-error approach and cannot predict in advance if a specific case has a solution. [Extracted from the article]

Emissions from transportation are one of the key factors preventing the achievement of carbon peaking and carbon neutrality by 2050, with particular attention to emissions from buses. Specifically, few research has been conducted on the exhaust emissions characteristics of liquified natural gas (LNG) buses under different driving scenarios. This study proposed a framework for predicting exhaust emissions of LNG buses based on the portable emission measurement system and GPS collaborative perception data. Firstly, the emission distribution characteristics of CO2, CO, HC, and NOx from LNG buses in real-world driving were analyzed by visualization methods. Then, the real-time exhaust emissions of LNG buses were predicted based on the temporal fusion transformers model for both urban and suburban sections of Zhenjiang City, and the model validity was verified. The current and past 10 s driving states were used for predicting the emission rate of LNG buses. The results showed that the proposed model outperforms other advanced algorithms in real-time exhaust emissions prediction of LNG buses, with an average R2 value higher than 0.94 and an average MAPE reduction of 14.19%. The error assessment revealed that the emission values and average emission rates are higher when driving in the urban section compared to the suburban section. Among the influencing factors, traffic conditions have the most significant impacts on the exhaust emissions of LNG buses, followed by road conditions and driving states, with relative feature importance of 48.9, 34.8, and 16.3%, respectively. Additionally, the current and past 10 s driving states also significantly influenced real-time predictions. This study provides an essential theoretical reference for reducing exhaust emissions for city buses. [ABSTRACT FROM AUTHOR]

This study aims to explore the use of Dielectric Barrier Discharge (DBD) technology for the joint treatment of methane (CH4) and nitrogen oxide (NO) in the exhaust of Liquid Natural Gas (LNG) engines during cold starts and at mid to low loads when the exhaust temperature is below 500 °C. Through experiment and numerical simulation, the effect of discharge power on the removal efficiency of CH4 and NO in the exhaust of LNG engines was investigated under the condition of simulated flue gas temperature at 438 °C. A plasma chemical model suitable for analyzing the mixture of N2/O2/H2O/CH4/NO in the exhaust gases of LNG engines was constructed and validated. The study found that the conversion efficiency of CH4 and NO exhibits different trends with the increase of discharge power, and CH4 tends to be oxidized to CO under plasma conditions. Key reaction pathways for the DBD treatment of CH4, NO, CO, and NO2 were identified, and an important chemical reaction pathway with the potential for the joint treatment of CH4 and NO was found: CH3O2 + NO → CH3O + NO2. Additionally, the crucial pathways for the stable conversion of NO to NO2 were identified: O + NO + N2 → NO2 + N2 and NO + O3 → NO2 + O2, providing forward-looking theoretical guidance for subsequent research on plasma-facilitated selective catalytic reduction of NOx by CH4. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive three-dimensional Computational Fluid Dynamics (CFD) analysis of the pre-cooling process of a Type B LNG tank using various refrigerants, including liquid nitrogen (LN), nitrogen gas (NG), liquefied natural gas (LNG), boil-off gas (BOG), and their combinations. The simulation model accounts for phase change (through the mixture multiphase model), convective heat transfer, and conjugate heat exchange between the fluid and the tank structure. The results indicate that liquid nitrogen is the most efficient refrigerant, achieving the highest cooling rate through both latent and sensible heat. LNG also demonstrated a relatively high cooling rate, 79% of that of liquid nitrogen. Gas-only pre-cooling schemes relying solely on sensible heat exhibited slower cooling rates, with BOG achieved 79.4% of the cooling rate of NG. Mixed refrigerants such as NG + LN and BOG + LNG can achieve comparable, while slightly slower, cooling than the pure liquid refrigerants, outperforming gas-only strategies. A further assessment of the heat transfer coefficient suggests the mixed cooling schemes have almost identical heat transfer coefficient on the inner tank surface to the liquid cooling scheme, over 5% higher than the gas refrigerants. The study also highlighted the uneven temperature distribution within the tank due to the bulkhead's blockage effect, which can induce significant thermal stress and potentially compromise structural integrity. Mixed schemes exhibit thermal gradients higher than those of gas schemes but lower than those of liquid schemes, while achieving cooling speeds comparable to liquid schemes if the inlet velocity of the refrigerants is properly configured. These findings offer valuable insights for developing safer and more efficient pre-cooling procedures for Type B LNG tanks and similar cryogenic storage tanks. [ABSTRACT FROM AUTHOR]

This study reports the comparative energy and exergy analysis of ortho-para hydrogen and non-ortho-para hydrogen conversion in hydrogen liquefaction process. Two cases were simulated, case A – hydrogen liquefaction with ortho-parahydrogen conversion and case B – hydrogen liquefaction without ortho-parahydrogen conversion. This is the first study that presents a comparative energy and exergy analysis between such two cases. In this research, a hydrogen liquefaction process was designed adopting cascaded five-stage Brayton refrigeration cycle. The process was simulated in Aspen PLUS. The process used a mixed refrigerant (of liquefied natural gas) refrigeration cycle to precool the gaseous hydrogen feed from 26 °C temperature to −192 °C temperature, and mixed refrigerant (of nelium) was subsequently used to further deep-cool the the hydrogen stream from −192 °C temperature to −245.99 °C temperature in the cryogenic section of the process. Liquefaction was achieved by expanding the hydrogen through Joule-Thomson valve at −248.37 °C and 1 bar. The simulated results of the two cases showed the specific energy consumption of case A to be 8.45 kWhr/kg LH , and that of case B to be 15.65 kWhr/kg LH respectively. The results also indicated a total exergy efficiency of 92.42% in case A and 87.18% in case B. The research results showed that the hydrogen liquefaction designed with configuration of ortho-parahydrogen conversion has better performance indicators than the liquefaction without ortho-parahydrogen conversion. Therefore, hydrogen liquefaction with ortho-parahydrogen conversion can be considered in the design and development of new hydrogen liquefaction plants. Process optimization is recommended to further enhance the specific energy consumption and exergy efficiency of both processes. • Comparative analysis of ortho-para and non-ortho-para hydrogen conversion. • Ortho-para Process is more energy efficient than non-ortho-para process. • Average exergy efficiency of 89.8% achieved in the analysed processes. • Integration of three refrigeration cycles to achieve hydrogen liquefaction. [ABSTRACT FROM AUTHOR]

For Egypt, ethane is a vital chemical precursor, with the potential to significantly attract financial resources and drive economic growth. Enhancing its added value necessitates efficient recovery of ethane before it enters the national grid without processing. This research investigates the technical and economic feasibility of integrating natural gas liquids (NGLs) from three Egyptian NGLs plants—South Western Desert NGLs (SWD NGLs), North Western Desert NGLs (NWD NGLs), and East Mediterranean NGLs (EMD NGLs)—to improve ethane recovery from natural gas fields. The study focuses on revamping these NGLs plants using various NGLs recovery techniques, conducting a comprehensive comparison to identify the most effective methods for processing rich feed gas. Detailed design of the NGLs recovery processes was developed using HYSYS V.14 simulation software and supplementary calculation sheets. The design criteria encompass both technical and economic parameters to ensure a holistic approach in meeting project requirements. Results indicate a significant increase in ethane recovery: 16% for SWD NGLs, 10% for NWD NGLs (A, B, C), and 85% for EMD NGLs. This improvement will boost ethane feedstock for petrochemical companies from 2000 ton/day to 3500 ton/day, enabling increased polyethylene production. Economic analysis for the base case shows an expected internal rate of return (IRR) of 26%, a net present value (NPV) of USD 73 million, and a payback period of approximately 3 years. Sensitivity analysis on product prices, feed gas prices, and total capital investment confirms the project's economic viability, with all cases showing feasibility (IRR ≥ 15%) except when product prices fall below USD 225/ton for propane, USD 215/ton for liquefied petroleum gas (LPG), and USD 25/bbl for condensate. This study highlights the potential for enhanced ethane recovery, offering substantial economic benefits and supporting the growth of Egypt's petrochemical industry. [ABSTRACT FROM AUTHOR]

This study focuses on optimizing the ship routing for Indonesia’s liquefied natural gas (LNG) logistics network using Mixed Integer Linear Programming (MILP). Indonesia's pivotal role in the global LNG market underscores the need for efficient logistics, especially given the challenges of limited port capacity, infrastructure, fluctuating demand, and environmental impact. MILP techniques were applied to address these challenges by optimizing vessel routes, minimizing costs, and reducing emissions. The research identified bottlenecks within Indonesia's logistics network and proposed optimized shipping strategies that enhance cost-effectiveness and operational efficiency. The findings contribute to sustainable energy logistics and provide actionable insights for stakeholders managing Indonesia's LNG supply chain. [ABSTRACT FROM AUTHOR]

Climate change has become a major agenda item in international relations and in national energy policy-making circles around the world. This review studies the surprising evolution of the energy policy, and more particularly the energy transition, currently happening in the Arabian Gulf region, which features some of the world's largest exporters of oil and gas. Qatar, Saudi Arabia, and other neighboring energy exporters plan to export blue and green hydrogen across Asia as well as towards Europe in the years and decades to come. Although poorly known and understood abroad, this recent strategy does not threaten the current exports of oil and gas (still needed for a few decades) but prepares the evolution of their national energy industries toward the future decarbonized energy demand of their main customers in East and South Asia, and beyond. The world's largest exporter of Liquefied Natural Gas, Qatar, has established industrial policies and projects to upscale CCUS, which can enable blue hydrogen production, as well as natural carbon sinks domestically via afforestation projects. [ABSTRACT FROM AUTHOR]

In this study, online ambient volatile organic compounds (VOCs) were collected at an urban site of Zhengzhou in Central China during February 2018. The VOCs characteristics, source contributions and the Chinese New Year (CNY) effects have been investigated. During the sampling period, three haze periods have been identified, with the corresponding VOCs concentrations of (92 ± 45) ppbv, (62 ± 18) ppbv and (83 ± 34) ppbv; in contrast, the concentration during non-haze days was found to be (57 ± 27) ppbv. In addition, the festival effects of the CNY were investigated, and the concentration of particulate matter precursor decreased significantly. Meanwhile, firework-displaying events were identified, as the emission intensity had been greatly changed. Both potential source contribution function (PSCF) and the concentration weighted trajectory (CWT) models results indicated that short-distance transportation was the main influencing factor of the local VOCs pollution, especially by transport from the northeast. Source contribution results by the positive matrix factorization (PMF) model showed that vehicle exhaust (24%), liquid petroleum gas and natural gas (LPG/NG, 23%), coal combustion (21%), industrial processes (16%) and solvent usages (16%) were the major sources of ambient VOCs. Although industry and solvents have low contribution to the total VOCs, their secondary organic aerosol (SOA) contribution were found to be relatively high, especially in haze-1 and haze-3 periods. The haze-2 period had the lowest secondary organic aerosol potential (SOAp) during the sampling period; this is mainly caused by the reduction of industrial and solvent emissions due to CNY. [ABSTRACT FROM AUTHOR]

In this study, the effects of fin configurations and layouts on thermal and hydraulic performances in a printed circuit heat exchangers with supercritical liquefied natural gas as the working fluid are numerically studied, and the overall heat transfer performance is evaluated by the thermal performance factor. Firstly, the effect of three different airfoil configurations, that is, NACA 0024, NACA 0024 with vortex generator, and NACA 0024 with curved vortex generator (CVG) is investigated. The comparative results indicate that NACA 0024 and CVG combined configurations offer the best overall heat transfer performance. Furthermore, the effect of the CVG minimum transverse distance is analyzed in detail. The results show that for a given CVG configuration, the CVG minimum transverse distance should not be too small or too large, so that the longitudinal vortices (LVs) generated will not interact with each other and the LVs' influences may reach a longer distance. The optimal CVG minimum transverse distance is 1.75 of maximum airfoil thickness. Finally, the effect of CVG attack angle is studied. The results indicate that the optimal CVG attack angle of combined configurations is 45° for improving the overall heat transfer performance, and an optimal CVG and airfoil fin arrangement is suggested. [ABSTRACT FROM AUTHOR]

The liquid natural gas (LNG) submerged pump is the core fluid transportation equipment in the LNG industry. The analysis of energy loss and flow characteristics can improve its performance. In this paper, the flow field is numerically simulated for a LNG cryogenic multistage pump and the energy loss is quantitatively evaluated using entropy generation theory. For each stage, there are significant differences for the energy loss and fluid flow at low flow rates, but they are basically the same except for the first stage when the operating flow rate is greater than 0.8Qd. The higher entropy generation appears in the gap between the impeller and the guide vane. In the first-stage impeller passage and import, the entropy generation is distinctly lower than that in other stages because the circumferential velocity gradient is reduced by the inducer pre-rotation. Meanwhile, as the shear force of the blade on the fluid weakens, the vortex at the first stage impeller can also be decreased. However, it has little effect on the energy loss caused by rotor–stator interaction at the impeller outlet. [ABSTRACT FROM AUTHOR]

Manual welding operations are performed inside the engine room of a liquefied natural gas carrier under construction. The welders are at risk of exposure to welding fumes in case of poor ventilation. Therefore, ventilation fans are installed at shipbuilding sites to improve indoor air quality. Although ensuring the respiratory health of welders is important, studies focusing on ventilation in the ship engine room have not been conducted. Therefore, the ventilation efficiency was evaluated herein based on the placement of ventilation fans to alleviate air stagnation using a computational fluid dynamic (CFD) model operating on Fluent. The mean age of air (MAA) was computed to assess the ventilation efficiency. In addition, particles with size and physical properties similar to welding fumes were sourced assuming 30 welders in the engine room. Results revealed that ventilation fan and/or exhaust in enclosed spaces contributes significantly to alleviating the MAA level. MAA and particle distribution did not correlate well due to the different properties of air and the iron oxide particle. Therefore, to determine the optimal ventilation fan displacement, particle motion should be studied along with performing MAA analysis. The proposed CFD model potentially guides to improvement of the working environments and respiratory health of welders. [ABSTRACT FROM AUTHOR]

Vietnam, a dynamic and rapidly developing country in Southeast Asia, is experiencing a surge in energy demand due to its booming economy and growing population. However, with the strong commitment of the Vietnamese government to achieve net-zero emissions by 2050 at COP 26, Vietnam needs to implement robust measures to reduce greenhouse gas emissions, with energy transition as a top priority. To meet this growing energy demand and minimize greenhouse gas emissions in the energy sector, Vietnam is turning its attention to liquefied natural gas (LNG), an environmentally friendly and versatile energy source. With the USA emerging as a major global exporter of LNG based on the shale gas revolution, Vietnam has recognized the potential to import LNG from the USA to meet its energy needs in a sustainable manner. The purpose of this article is to analyse the reasons why Vietnam has prospects for importing LNG from the USA. [ABSTRACT FROM AUTHOR]

This paper explores the temporalities behind resource nationalism and the liquefied natural gas project (LNG) in Tanzania. At a cost of $42 billion, the LNG project would be one of the most capital-intensive projects in Africa and would allow for export of Tanzanian gas. Focusing on the LNG negotiations during the rule of John Pombe Magufuli, this paper uses interviews with key stakeholders involved in the negotiation and planning of the LNG project, both from the government and the hydrocarbon sector. It argues that competing imaginaries of the future of the gas sector in Tanzania has led to friction between actors and has resulted in slow progression for the project. Central to this has been competing short-, medium-, and long-term time horizons, contrasting market and electoral cycles, and differing imaginaries of what the future of LNG holds for the country. This paper's core argument is that competing perceptions of the future between different actors involved in the project, have allowed for friction between actors. At its core, this is through how the future was constructed for actors, be it through development strategies, price forecasts, or different imagined futures. [ABSTRACT FROM AUTHOR]

Although shipping is the most energy efficient method of transporting trade goods it is held accountable for 2–3% of global greenhouse gas (GHG) emissions. The shipping industry is exploring pathways to carbon–neutral fuels to help eliminate GHG emissions by 2050. To date research on alternative fuels has not considered public opinion; it remains unclear whether the public will support alternative shipping fuels, or whether public opposition might prevent or defer their deployment. To fill this knowledge gap and help the industry and policy makers arrive at publicly acceptable decisions, our research examines UK public perceptions of six shipping fuels using a mixed-method approach. Our findings reveal that biofuels and hydrogen are clearly favoured, owing to biofuel's perceived low risk and hydrogen's lack of negative by-products. Perceptions of liquid natural gas are somewhat positive, suggesting that it provides an acceptable near-term option while other fuels are developed. Despite lingering stigma, nuclear is preferred over the incumbent heavy fuel oil, though both are perceived negatively. However, the UK public strongly dislike ammonia, perceiving it as unproven, risky, and lacking availability. A third support use of alternative shipping fuels, with support greater from those living near ports—a "yes in my back yard" effect. The results demonstrate that different alternative fuels are likely to elicit different public reactions as they become more widely known and show how the overall evaluations arise from specific positive or negative associations with each fuel. [ABSTRACT FROM AUTHOR]

The high demand for natural gas (NG) worldwide has led to an increase in the size of the LNG carrier fleet. However, the heat losses from this type of ship's engines are not properly managed, nor is the excess boil-off gas (BOG) effectively utilised when generation exceeds the ship's power demand, resulting in significant energy losses dissipated into the environment. This article suggests storing the lost energy into green H2 for subsequent use. This work compares three different electrolysis technologies: solid oxide (SOEC), proton exchange membrane (PEME), and alkaline (AE). The energy required by the electrolysis processes is supplied by both the LNG's excess BOG and engine waste heat through an organic Rankine cycle (ORC). The results show that the SOEC consumes (743.53 kW) less energy while producing more gH2 (21.94 kg/h) compared to PEME (796.25 kW, 13.96 kg/h) and AE (797.69 kW, 10.74 kg/h). In addition, both the overall system and SOEC stack efficiencies are greater than those of PEME and AE, respectively. Although the investment cost required for AE (with and without H2 compression consideration) is cheaper than SOEC and PEME in both scenarios, the cost of the H2 produced by the SOEC is cheaper by more than 2 USD/kgH2 compared to both other technologies. [ABSTRACT FROM AUTHOR]

In the current research, an ocean thermal energy conversion (OTEC) assisted multi-generation process with a transcritical Rankine cycle (tRC) working with carbon dioxide is proposed for green hydrogen, oxygen, and distilled water production. The suggested utilizes thermal energy from the ocean to drive tRC, where the liquefied natural gas (LNG) subsystem acts as the heat sink. The process also comprises an LNG turbine to take advantage of LNG cold energy, a proton exchange membrane electrolyzer (PEM-El) unit for hydrogen and oxygen production, photovoltaic/thermal (PV/T) collectors, and reverse osmosis (RO) desalination unit with a recovery turbine. For the thermodynamic evaluation, a numerical model is engineered for the system, and the evaluation of the system's performance in terms of energy and exergy is conducted. According to the analysis, the total net power obtained from the hybrid system is calculated as 1734 kW, while the overall energy efficiency of the system is found to be 26.3%. In addition, the total exergy destruction is determined as 4859 kW with an exergy efficiency of 35.5%. Furthermore, H 2 and distilled water production rates are estimated as 1.349 kg/h and 10.31 m3/h, respectively. • A novel design for an ocean thermal energy conversion-based combined plant is proposed. • Energetic and exergetic performance of the hybrid system is analyzed. • The overall energy and exergy efficiencies are 26.3% and 35.5%, respectively. • The highest contributor to the irreversibility rate is found to be the condenser with 3265 kW. [ABSTRACT FROM AUTHOR]

The pre-cooling of a large LNG storage tank involves complex phenomena such as heat transfer, low-temperature flow, gas displacement, and vaporization. The whole pre-cooling process could take up to 50 h. For large-scale, full-capacity storage tanks, it is particularly important to accurately control the pre-cooling temperature. Digital twin technology can characterize and predict the full life cycle parameters from the beginning of pre-cooling development to the end and even the appearance of damage in real time. The construction of a digital twin platform requires a large number of data samples in order to predict the operating state of the device. Therefore, a simulation method with high computational efficiency for the pre-cooling process of LNG tanks is of great importance. In this paper, the mixture model and discrete phase model (DPM) are applied to simulate the pre-cooling process of a large LNG full-capacity tank. Following Euler–Lagrange, the DPM greatly simplifies the solution process. Compared with the experimental results, the maximum error of the DPM simulation results is less than 11%. Such a highly efficient simulation method for the large LNG full-capacity storage tank can make it possible to build the digital twin platform that needs hundreds of data model samples. [ABSTRACT FROM AUTHOR]

In this study, a novel TIP–TIG (TT) automatic welding method was used to weld the girth seams of liquefied natural gas (LNG) tanks composed of 9% nickel steel. The microstructure of the joints was characterized via electron microscopy and x-ray diffraction. The tensile strength and ductility of the joints were evaluated via tensile testing. The low-temperature toughness of the joints was investigated via low-temperature impact testing at - 196 °C. This increased the toughness and strength of the TT-welded joint compared to the corresponding values of joints welded using conventional submerged arc welding (SAW). A comparison with the SAW-welded joints revealed that the TT-welded joint presented high strength and excellent low-temperature toughness, which can be primarily attributed to the low heat input. Compared with SAW, TT welding resulted in a lower joint dilution ratio, smaller heat-affected zone, and lower degree of grain coarsening. In addition to fine austenite, as the joint microstructure and several uniformly distributed carbides in the weld seam. These properties hindered the dislocation slip. However, they promoted precipitation strengthening and grain refinement and provided excellent low-temperature toughness to the TT-welded joints. Notably, TT welding does not require weld-bead cleaning between passes. Additionally, owing to improvements in the degree of automation for TT welding, the welding time can be further matched with that of SAW. TT welding with narrow-gap grooves reduces the required amount of filler metal by more than 50%. Therefore, the TT welding process is significantly advantageous and can replace SAW for girth–seam welding of LNG storage tanks. [ABSTRACT FROM AUTHOR]

Liquefied natural gas (LNG), recognized as the fossil fuel with the lowest carbon emission intensity, is a crucial transitional energy source in the global shift towards low-carbon energy. As the natural gas industry undergoes rapid expansion, the complexity of investment business models has increased significantly. Optimizing the combination of various segments within the value chain has become standard practice, making it essential to control risks and enhance economic benefits in these multifaceted scenarios. This paper introduces an integrated economic model encompassing upstream, liquefaction, shipping, regasification, and consumption, suitable for both upstream and downstream integration. The model offers a comprehensive analysis of the primary business models and key factors across each segment of the value chain. By constructing a robust economic evaluation framework, the study aims to provide a holistic approach to understanding the economic feasibility of LNG projects. Two detailed case studies are conducted to demonstrate the application and effectiveness of the proposed model, highlighting its capability to guide investment decisions, support risk management, and optimize asset portfolios. The integrated economic model developed in this study serves as a valuable tool for stakeholders in the LNG industry. It not only facilitates informed investment decision-making but also enhances the strategic management of risks and resources. By leveraging this model, investors and managers can better navigate the complexities of the LNG business, ensuring sustainable and economically viable operations. [ABSTRACT FROM AUTHOR]

Due to the extensive utilization of liquid nature gas (abbreviated as LNG) resources and a multitude of considerations, LNG storage tanks are gradually transitioning towards smaller footprints and heightened safety standards. Consequently, underground LNG storage tanks are being designed and constructed. However, underground LNG storage tanks release a considerable quantity of cold into the ground under both accidental and normal conditions. The influence of cold results in the ground freezing, which further compromises the safety of the structure. Existing research has neglected to consider the effects of this. This oversight could potentially lead to serious safety accidents. In this work, a complete set of experiments using a novel LNG underground storage tank fluid-solid-thermal coupled cryogenic leakage scale model were conducted for the first time to simulate the effect of the tank on the soil temperature field, stress field, and displacement field and to analyze the development of the three fields and the results of the effect. This research helps the related personnel to better design, construct, and evaluate the LNG underground storage tanks to avoid the catastrophic engineering risks associated with cryogenic leakage and helps to improve the design process of LNG underground storage tanks. [ABSTRACT FROM AUTHOR]

The liquefied natural gas (LNG) fuel tank in a large container ship is loaded with liquid LNG at an ultra-low temperature (-163°C), there is a significant temperature difference in the cargo hold area where the entire fuel tank is located, which will have an important impact on the steel grade design and structural safety of the cargo tank in container ship. This paper develops two heat transfer models using Computational Fluid Dynamics method (CFD method) and an analytical method to analyze the temperature distribution in a large container ship equipped with Type-B LNG fuel tank. These models incorporate the arrangement and heat transfer characteristics of LNG fuel tanks. The temperature field analysis is conducted under typical the environmental conditions specified in the Code for the Construction and Equipment of Ships Transporting Liquefied Gas in Bulk (IGC Code) and the United States Coast Guard Code (USCG Code), based on the CFD method and the analytical method, and the results of temperature field distribution are compared. Additionally, a parametric analysis of the hull temperature field is further carried out, the results show that the thermal conductivity of the insulation layer in LNG storage tanks and the types of the loaded liquid cargo have a limited impact on the final temperature field distribution in hull structure. However, the selection of steel grade in the local structure of the cargo hold, especially in the inner hull part, may lead to significant changes. [ABSTRACT FROM AUTHOR]

Floating Production Storage and Offloading (FPSO) unit being an offshore vessel, storing and producing crude oil, prior to crude oil being transported by accompanying shuttle tanker. Critical mooring/hawser strains during offloading operation have to be accurately predicted, in order to maintain operational safety and reliability. During certain types of offloading, excessive hawser tensions may occur, causing operational risks. Current study examines FPSO vessel's dynamic reactions to hydrodynamic wave-induced loads, given realistic in situ environmental conditions, utilizing the AQWA software package. Current study advocates novel multi-dimensional spatiotemporal risks assessment approach, that is particularly well suited for large dataset analysis, based on numerical simulations (or measurements). Advocated multivariate reliability methodology may be useful for a variety of marine and offshore systems that must endure severe environmental stressors during their intended operational lifespan. Methodology, presented in this study provides advanced capability to efficiently, yet accurately evaluate dynamic system failure, hazard and damage risks, given representative dynamic record of multidimensional system's inter-correlated critical components. Gaidai risk assessment method being novel dynamic multidimensional system's lifetime assessment methodology. In order to validate and benchmark Gaidai risk assessment method, in this study it was applied to FPSO and potentially LNG (i.e., Liquid Natural Gas) vessels dynamics. Major advantage of the advocated approach is that there are no existing alternative risk assessment methods, able to tackle unlimited number of system's dimensions. Accurate multi-dimensional risk assessment had been carried out, based on numerically simulated data, partially verified by available laboratory experiments. Confidence intervals had been given for predicted dynamic high-dimensional system risk levels. [ABSTRACT FROM AUTHOR]

Liquefied natural gas carrier (LNGC) orders are increasing owing to marine environment regulations. The complexity of the integrated system applied to shipbuilding and software errors have increased with the high degree of automation. Direct on-site inspection methods are associated with high costs and safety risks, whereas software-based simulations rely heavily on the accuracy of the models of power system components. Hardware-in-the-loop simulation (HILS) can be utilized for designing and testing intricate real-time embedded systems. Specifically, HILS offers a reliable means of evaluating power management system (PMS) performance for LNGCs, which are high-value vessels commonly used in offshore plants. This study proposes a PMS–HIL test bed comprising a power supply unit, consumer, simulation control console, and main switchboard. The proposed HILS test bed utilizes the real equipment data of the shipbuilding industry to replicate the conditions associated with actual LNGCs. The proposed system is verified and validated through a software acceptance test procedure. Additionally, load-sharing, load-dependent start, blackout prevention, and preferential tests are performed for the PMS function evaluation. Test results indicate that the proposed system has great potential for conventional PMS commissioning. Therefore, it exhibits the potential to replace traditional factory acceptance tests. Additional development of the system will be conducted for ship automation, utilizing PMS control and an energy management system. [ABSTRACT FROM AUTHOR]

Transporting natural gas in liquid form increases opportunities for storage and export worldwide, thus making transportation more sustainable. However, liquefied natural gas (LNG) is in an unsteady state, leading to LNG conversion to the gas state occurring throughout the storage, loading, unloading, and transportation processes. To observe the transition of LNG to natural gas, mathematical models are developed to monitor technical parameters. This research analyses a floating storage and regasification unit for and adopts a mathematical model of the LNG regasification system, aiming for improved observation of hydrodynamic, dynamic, and thermo-physical properties. The complex mathematical model of the system was implemented using the Fortran programming language and MATLAB R28a. From the investigation of the total LNG regasification system, it could be concluded that increasing the outlet pressure of the system results in a decrease in the velocity of LNG. It was found that the total hydraulic energy losses of the total LNG regasification system were approximately 41.3 kW (with outlet pressure of 2 MPa), 12.75 kW (with outlet pressure of 5 MPa), and 4.24 kW (with outlet pressure of 7 MPa). [ABSTRACT FROM AUTHOR]

As the receiving terminal of liquefied natural gas (LNG), the efficient emergency response of the floating storage and regasification unit (FSRU) is crucial to ensure the safety of LNG transportation at sea. However, few existing literature study the risk issues of FSRUs during emergency operations. In order to improve the emergency response capability of FSRU, this study proposes an innovative assessment method to identify hazards, quantify and rank the risks associated with emergency response and disposal operations of FSRU accidents. Firstly, a comprehensive index hierarchy system applicable to human, equipment, environment, and management aspects of emergency response and disposal operations of FSRU accident is established through an extensive literature review, analysis of accident reports, and expert judgments. Secondly, based on the concept of Intuitionistic Fuzzy Numbers, the Intuitionistic Fuzzy Hybrid Weighted Euclidean Distance (IFHWED) operator is used to enhance the conventional FMEA approach. This method considers the varying levels of expert confidence and integrates subjective and objective weights of risk influential factors (RIFs), and the efficacy is validated through sensitivity analysis. Finally, a comprehensive evaluation model employing the Analytic Hierarchy Process (AHP) and fuzzy comprehensive evaluation algorithms is used to aggregate the risk values of RIFs. The findings of this study offer decision-makers insights into risks during emergency operation, provide valuable guiding strategies for FSRU accident management, and improve the capability for emergencies at sea. [ABSTRACT FROM AUTHOR]

Bu çalışmada, ağır ticari araç sınıfında yer alan bir çekicinin performansı dizel ve sıvılaştırılmış doğal gaz (LNG) yakıtlı bir motora sahip olması durumunda deneysel olarak incelenmiştir. Testler sırasında her iki çekicide Euro VI normlarına sahip 338 kW gücünde motor kullanılmıştır. Araçlar toplam 41000 kg ağırlıkta eğimsiz düz bir yolda kullanılarak 85 km/h hızdan 20 km/h hıza serbest yavaşlama ve kalkıştan 85 km/h hıza ulaşana kadar hızlanma testlerine tabi tutulmuştur. Ayrıca 164,3 km’si otoyol, 44,4 km’si kırsal yol ve 54,7 km’si şehir içi yol olmak üzere toplam 263,4 km’den oluşan bir güzergâhta kullanılan araçların ortalama yakıt tüketim maliyetleri hesaplanmıştır. Sonuçlara göre, LNG yakıtlı aracın 100 km için yakıt maliyeti 1003,58 TL dizel aracın ise 1359,32 TL olarak hesaplanmıştır. LNG yakıtlı aracın ilk satış maliyetinin %30 daha pahalı olacağı öngörüldüğünde bile elde edilmiş olan %27 oranındaki yakıt tasarrufunun uzun yol kullanılan bir araç için kayda değer bir sonuç olduğu anlaşılmaktadır.

Canada’s Ad Standards Council ruled advertising from a pro-LNG group created a ‘misleading’ impression. Now it’s time for a thorough correction of the public [...]

The lack of freshwater in many countries pushes authorities to utilize desalination units. Solid Oxide Fuel Cells (SOFC) have shown promising results to provide the power to establish a multi-generation system using hydrogen as a renewable source. In this article, to better improve the efficiency of the suggested integrated system, the waste heat of the SOFC is recovered through the application of a Kalina power cycle and Humidification-dehumidification (HDH) desalination unit. Liquefied Natural Gas (LNG) cold stream also utilizes the waste heat of the Kalina cycle (KC) to provide cooling and power simultaneously. As all the considered cycles of Kalina, LNG cold stream, and SOFC can produce power and as this amount of electricity would be higher than the grid's demand, a further Reverse Osmosis (RO) desalination unit is utilized to increase the output amount of freshwater in the proposed system. The main focus of this study is to perform the thermodynamic analysis of this tri-generation system, which can generate power, cooling, and freshwater. Results indicate that the exergy and energy efficiencies of the current suggested system when the current density of the SOFC is 550 (A/ m 2), is around 55% and 60%, respectively. • Suggesting a novel system to produce freshwater, electricity, and cooling. • Thermodynamic analysis of the proposed novel tri-generation system. • Having energy and exergy efficiencies of 60% and 55%, respectively. • Parametric study considering the changes in the SOFC's current density. [ABSTRACT FROM AUTHOR]

The influence of different air supply modes on the vaporization performance of a finned tube in LNG ( liquefied natural gas) ambient air vaporizer was investigated by the FLUENT software, and the distribution of air physical parameters around the tube on different air supply modes i. e., the bottom air supply and top air exhaust mode, the top air supply and bottom air exhaust mode, the side-air supply and top air exhaust mode, and the side-air supply and bottom air exhaust mode were analyzed. The vaporization process of liquefied natural gas in the tube was investigated by using the Lee model. The effects of air supply mode and air inlet velocity on the vaporization capacity of the finned tube were analyzed by considering the variation of fluid temperature in the tube. The results indicate that the low wind speed boundary layer appears around the finned tubes, and a wake range with poor heat exchange efficiency is likely to be formed on the leeward side of the tube for side air-supply modes. When the air inlet velocity increases from 2. 8 m/ s to 3. 8 m/ s, and from 3. 8 m/ s to 4. 8 m/ s, the maximum heat transfer coefficients on the air side increase by 3. 92 and 2. 6 W/ (m²·K) respectively for the side-air supply and bottom air exhaust mode. The boundary layer distribution for the bottom air supply mode and the top air supply mode is uniform, and the maximum recommended air inlet velocity is 3. 2 m/ s because the heat transfer performance does not increase significantly with the rise on the air velocity. The vaporization performance of the finned tube on the top air supply mode is better than that on the bottom air supply mode. Among the four air supply modes, the side-air supply and top air exhaust mode is the best one to improve the heat transfer performance of the single finned tube. The forced-draft AAV ( ambient air vaporizer) using the side-air supply and top air exhaust mode has a much better vaporization performance than the general AAV. [ABSTRACT FROM AUTHOR]