LNG Applications Research Articles

Risk Assessment and Application of Port Liquefied Natural Gas Trucks Bunkering Based on Hazard Identification and Computational Fluid Dynamics

In order to safely and orderly promote the application of LNG as a clean energy for inland river ships, the paper takes a port truck to bunker a 2000 tons LNG power bulk carrier for example, carrying out a qualitative risk assessment based on HAZID method, putting forward risk prevention and control measures, and using FLACS software to get CFD accident consequence quantitative calculation. The analysis shows that the overall risk is controllable under certain measures. It is the first time that this method has been applied to the risk assessment of Trucks Bunkering.

Influence of flow disturbances on the performance of industry-standard LNG flow meters

In the last decade significant progress has been achieved in the development of measurement traceability for LNG inline metering technologies such as Coriolis and ultrasonic flow meters. In 2019, the world's first LNG research and calibration facility has been realised thus enabling calibration and performance testing of small and mid-scale LNG flow meters under realistic cryogenic conditions at a maximum flow rate of 200 m3/h and provisional mass flow measurement uncertainty of 0.30% (k = 2) using liquid nitrogen as the calibration fluid. This facility enabled, for the first time, an extensive test programme of LNG flow meters under cryogenic conditions to be carried out to achieve three main objectives; the first is to reduce the onsite flow measurement uncertainty for small and mid-scale LNG applications to meet a target measurement uncertainty of 0.50% (k = 2), the second is to systematically assess the impact of upstream flow disturbances and meter insulation on meter performance and the third is to assess transferability of meter calibrations with water at ambient conditions to cryogenic conditions. SI-traceable flow calibration results from testing six LNG flow meters (four Coriolis and two ultrasonic, see acknowledgment section) with water in a water calibration facility and liquid nitrogen (LIN) in the LNG research and calibration facility under various test conditions are fully described in this paper. Water and LIN calibration data were compared and it was observed that the influence of removing the meter insulation on mass flow rate measurement accuracy can be more significant (meter error > ±0.50%) than the influence of many typical upstream disturbances when the meter is preceded by a straight piping length equal to twenty pipe diameters (20D) with no additional flow conditioning devices, in particular for ultrasonic meters. The results indicate that the correction models used to transfer the water calibration to cryogenic conditions (using LIN) can potentially result in mass flow rate measurement errors below ±0.5%, however, the correction models are specific to the meter type and manufacturer. This work shows that the target measurement uncertainty of 0.50% can be achieved if the expanded standard error of the mean value measured by the meter is smaller than 0.40% (k = 2). It is planned to repeat these tests with LNG in order to compare the results with the LIN tests presented in this paper. This may reveal that testing with an explosion safe and environmentally friendly fluid such as LIN produces representative results for testing LNG flow meters.

The effect of geometrical modifications to a shell and tube heat exchanger on performance and freezing risk during LNG regasification

The regasification of LNG is a crucial process in a majority of LNG applications and can be conducted in various types of heat exchangers. The low boiling temperature of LNG makes the vaporization process prone to the risk of ice formation, which can obstruct the flow of the heating fluid. This, in turn, can lead to a significant drop in pressure, decrease in heat transfer or even to the destruction of the heat exchanger itself. In a wide range of important applications, the heating fluid is often water or a water-glycol mixture, characterized by a freezing temperature that is substantially higher than the boiling temperature of LNG. Consequently, this can intensify the ice formation process. In the current research, a numerical model was proposed and developed to analyze the risk of ice formation during the LNG vaporization process within a shell-and-tube type of heat exchanger (STHX). The model consists of two distinct parts: heat transfer through the boiling LNG and the freezing dynamics of the heating fluid. To generalize the developed model for various boiling regimes a continuous and differentiable expression of the boiling curve of LNG was proposed. The expression smoothly connected the nucleate with the film boiling regions and methodically filled the gap of the transition region. The developed numerical model was used to investigate a wide range of flow conditions and various shapes and spacing of tubes within the STHX. It was shown that the risk of total freezing could be indicated by a critical value of the Reynolds number. The conducted study made it possible to define a heat-flux-to-pump-duty-ratio coefficient, which showed that flattened tubes could ensure better heat transfer, higher reliability and also decrease the pump duty needed to supply the STHX.

Experimental and simulation study on the capacitive liquid level gauge of LNG vehicular cylinder

Abstract To obtain a high precision and intelligent level gauge in LNG vehicular cylinder, the three capacitive liquid level gauges (CLLGs) were developed through theoretical analysis, numerical simulation and experiment. Firstly, the composition distributions of LNG along different liquid levels under sloshing condition were simulated. The optimal heights of the two reference sensors in CLLG are 1/2 and 1/5 of the height of LNG vehicular cylinder, respectively. Secondly, the signal converter was developed based on the program design of single chip microcomputer and filter system. Thirdly, the liquid level measurement experiments of single/multi-component were carried out using single CLLG and three CLLGs under the static and sloshing condition. The average relative error of three CLLGs under sloshing condition is only 3.61%, which satisfies the high precision measurement of LNG vehicle. The three CLLGs can promote the development of LNG vehicle and play an important role in the application of LNG.

Synergistic Emission Reduction of SO2 and CO2 Based on Clean Energy Replacement in ports

China’s energy-saving emission reduction policy calls for improved air quality while reducing greenhouse gas emissions. This paper takes the container terminal as the research object, the energy saving and emission reduction of clean energy alternative fuels such as solar energy, wind energy, geothermal energy, LNG and electricity are studied through the combination of energy substitution and emission factors. In particular, SO2 and CO2 Synergistic mitigation effect. The results show that the reduction SO2 and CO2 is positively correlated with the usage of clean energy amount. Among them, LNG has the greatest contribution to the coordinated emission reduction of SO2, and solar energy contributes the most to CO2 reduction. Our conclusion is that the use of LNG and shore power in ports can achieve better synergistic emission reductions for SO2 and CO2. And through the use of air sources, solar energy, wind energy and light energy, CO2 emission reduction effect is better than SO2 emission reduction. The Chinese government can use this method as a policy tool for energy conservation and emission reduction, and vigorously promoted the application of LNG and shore power in ports.

Study on Calculation of Liquid Level And Storage of Tanks for LNG-fueled Vessels

As the ongoing development of the application of LNG as a clean energy in waterborne transport industry, the fleet scale of LNG-fueled vessels enlarged and the safety operation has attracted more attention in the industry. Especially the accurate detection of liquid level of LNG tanks is regarded as an important issue to ensure a safe and stable operation of LNG-fueled ships and a key parameter to keep the proper functioning of marine fuel storage system, supply system and safety control system. At present, detection of LNG tank liquid level mainly adopts differential pressure detection method. Liquid level condition could be found from the liquid level reference tables. However in practice, since LNG-fueled vessels are generally not in a stationary state, liquid state within the LNG tanks will constantly change, the detection of storage of tanks only by reference to the tables will cause deviation to some extent. By analyzing the temperature under different pressure, the effects of temperature change on density and volume integration calculation, a method of calculating the liquid level and storage of LNG tanks is put forward making the calculation of liquid level and actual storage of LNG tanks more accurately and providing a more reliable basis for the calculation of energy consumption level and operation economy for LNG-fueled vessels.

Life cycle assessment and optimization analysis of different LNG usage scenarios

This paper aims to compare the environmental impacts of LNG in different life cycle stages and for various usages by applying life cycle assessment (LCA). According to different usage processes, we set three scenarios including S1-hydrogen production, S2-electricity generation, and S3-vehicle fuel to evaluate their environmental impacts. Furthermore, in order to satisfy better city development, an optimization analysis was made to identify the optimal distribution structure of LNG. The environmental impact analysis of LNG was conducted using life cycle assessment and CML2001 method. LCA was performed based on the ISO 14040 standard using GaBi 5.0 software. Four impact categories (i.e., global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), and photochemical ozone creation potential (POCP)) were considered. Sensitivity analysis was also made by means of GaBi 5.0 software. Crystal Ball software was applied to make the optimization analysis for different LNG usage scenarios. The minimum environmental impact factor was taken as the objective function to confirm the optimal distribution structure of LNG. The LCA results indicate that the environmental impacts of the gasification and usage stages far outweigh that of the transportation stage, and the highest environmental impact category for each scenario is GWP. The largest contribution factor to GWP of S1 is the production supply of imported electricity, whereas the largest contribution factor to GWP of S2 and S3 is the emissions. The optimization analysis indicate that when imported LNG is allocated 25% for hydrogen production, 73% for electricity generation and 2% for vehicle fuel, the GWP and cost of the total LNG usage are both minimum. Environmental analysis on different LNG usage scenarios allows the identification and selection of comprehensive LNG usage plans with the minimum environment impacts and lowest cost. For different LNG usage scenarios, the GWP of LNG used for vehicle fuel is the highest and for hydrogen production is the lowest. The production supply of imported electricity and the emissions are the two largest contribution factors to LCA results as well as the sensitivity analysis results of the three scenarios. The optimization analysis method and results can provide technology reference for scientific urban planning of LNG application and allocation.

Facilitating the implementation of LNG as an alternative fuel technology in landlocked Europe: A study from Austria

Liquefied Natural Gas, LNG, is known to be an innovative alternative fuel technology. However, there are severe barriers which impede the application of LNG in the landlocked areas of Europe. Above all, the necessary infrastructure which could stimulate the spacious application of LNG is still lacking there. The objective of the present work is therefore to build a basement for launching LNG in this region. This will be carried out in two stages: First by deliberately examining the potential demand for LNG to see if the construction of LNG infrastructure is viable in this region and second by identifying the stakeholders which have to be taken into account to successfully accomplish this process. Therefore, a demand analysis has been carried out by interviewing 15 potential Austrian pioneer users with capacious vehicle fleets. Their requirements towards LNG application have been categorized and prioritized using Maslow's hierarchy of needs. Finally, a stakeholder matrix evaluates crucial stakeholders and gives an indication of how to deal with them appropriately. The results reveal that interest for LNG exists and the potential for introducing LNG in landlocked Europe is given.

Cryogenic Fatigue and Stress-strain Behavior of a Fibre Metal Laminate

This paper reports on the cryogenic fatigue life of Al 2024 / Stycast 2850 FT composite sandwiches loaded under cyclic strain, as well as on the strength of their constituent materials at 77K. These Fibre Metal Laminate (FML) specimen serve as a model for an alternative class of cryogenic structural materials that might be used e.g. in downstream LNG applications. FMLs, such as the GLARE ™, are already used in the aeronautic industry, where they provide better damage tolerance, corrosion resistance and lower specific weight. Their cryogenic performance, however, is yet to be understood. Preliminary results show that the metal/filled- epoxy combination presented here withstands repeated cool-down to 77K. Moreover, its cryogenic fatigue life is at least 20 times longer than at room temperature. These observations are consistent with the measured stress-strain behaviour of the metal and the epoxy, as well as with the shear strength of the bond between them. The Youngs modulus, yield strength and tensile strength of the Stycast 2850 FT roughly double when cooled down to 77K. In addition to this, the bond strength with the GLARE-type coated Al increases significantly. These preliminary experiments indicate that cryogenic FML are technically feasible.

LNG Distributed Energy Brings New Opportunity for Port Power Optimization in China

This article tries to bring you an idea that using LNG distributed energy system in domestic ports. Ports used LNG instead of diesel as fuel for container trailers and bulk cargo loaders. The quantity of LNG consumption of port is in small scale with this way. LNG distributed energy will be good for port power optimization. It can decrease emission and improve port environment. Under the rapid growth and development of LNG application in China, it’s time to study this subject now. At the end of article, the author gives some questions about how to well use LNG distributed energy for deep studies in the future.

Long-term regression of experimental endometriosis in a rat model treated with local application of levonorgestrel-loaded biodegradable microspheres

A previous study demonstrated that local application of levonorgestrel-loaded polylactic acid microspheres (LNG microspheres) resulted in significant regression of endometriotic cysts in a rabbit model for 6 months without disturbing the metabolic parameters or ovarian function. In order to investigate the feasibility of local application of LNG microspheres as a long-term maintenance treatment for endometriosis, the suppressive effect of a single intra-cystic injection of LNG microspheres was studied for 1 year in a rat model. Twenty four rats with experimental endometriotic cysts were randomized to be treated with a single intra-cystic injection of LNG microspheres (n = 8); 6-month GnRH agonist (GnRHa, n = 8) or control (n = 8). Intra-cystic injection of LNG microspheres and GnRHa treatment caused comparable regression and atrophy in endometriotic cysts in the first 6 months. Compared with the control, the wet weight of the endometriotic cysts was significantly lower in both groups at Month 6 but by Month 12 only remained low in the LNG microspheres group (P < 0.01). The immunostaining of estrogen receptors (ERs) in both the epithelium and stroma and progesterone receptors (PRs) in the stroma was significantly weakened in the LNG microspheres group at Month 6 and was not fully restored at Month 12 (P < 0.01). Metabolic parameters and estrous cycle were not disturbed by local application of LNG microspheres. In a rat endometriosis model, the suppressive effect of a single intra-cystic injection of LNG microspheres was comparable to that of GnRHa, and was maintained for 1 year. The down-regulation of ERs and PRs might serve as possible mechanism of long-term effectiveness.

Synthesis of mechanical driver and power generation configurations, Part 2: LNG applications

AbstractOptimization framework for the synthesis of power systems has been presented in Part 1 of this article, which systematically identifies the most cost‐efficient number, type, and model of mechanical drivers, together with optimal arrangement for compressor stage, helper motors or generators, and power plants. The developed methodology is applied to an LNG case study in which optimal and near‐optimal systems at various economic scenarios are identified. Also, a systematic methodology for the integrated design of refrigeration and power systems has been addressed to improve the overall design of low temperature processes. Additional key degrees of freedom such as stage pressure ratios and plant capacity are optimized, alongside other design variables, which provide greater flexibility in the matching of power supply and demands. This strategy is applied to an LNG case study and shows the convenience of this approach as the interactions between the refrigeration and power systems are systematically exploited. © 2010 American Institute of Chemical Engineers AIChE J, 2010

Minimum Mass Polymer Seawater Heat Exchanger for LNG Applications

The present study explores the thermofluid characteristics of a corrosion-resistant, thermally enhanced polymer composite, seawater-methane heat exchanger module for use in the liquefaction of natural gas on offshore platforms. Several metrics, including the heat transfer rate, the mass-specific heat transfer rate, and the total coefficient of performance (COPT), are used to compare the thermal performance of polymer composites having a range of thermal conductivities with that of corrosion-resistant metals. For operating conditions considered typical of the natural gas liquefaction industry in the Persian Gulf, a 10 W/m K polymer composite is found to provide nearly identical heat transfer rate to that of a corrosion-resistant titanium heat exchanger, almost 50% higher mass-specific heat transfer than for titanium (at 200 W pumping power), and COPT values approximately twice that of a least-material titanium heat exchanger. The results contribute to establishing the viability of using polymer composites for gas-liquid heat exchanger applications involving seawater and other corrosive fluids.

Significant benefits with a cylindrical hull for FPSO, drilling, LNG, and offshore power plant applications

Significant benefits with a cylindrical hull for FPSO, drilling, LNG, and offshore power plant applications

Development of 9% Nickel Steel for LNG Applications

Liquefied natural gas is usually transported by specially equipped ships and stored in LNG terminals. The construction of vessels and tanks for LNG transportation purposes leads to a demand for steels with specified low temperature properties. This article presents the development of 9%-nickel-alloyed high-strength steels for low temperature applications and gives an overview on their production, properties, and processing behaviour. Heavy plates of these steels meet the highest demands on strength, toughness and resistance against brittle fracture. Furthermore, an insight into industrial production experience is given and some current applications of nickel steel plates are illustrated. (orig.)

Overall design of low temperature processes

A methodology for the overall design and analysis of low temperature processes is proposed. A low temperature process such as the cold end of ethylene consists of three main components; the process (usually distillation), the heat exchange system (cold box and other exchangers), and the refrigeration system. The task of overall design is complex since all three components are interlinked and interactive. The proposed approach allows the designer to resolve these interactions and combine all three components in one design task. The approach is based on a combination of Pinch Analysis and Exergy Analysis. The overall design of low temperature processes is dominated by the shaftwork or power consumption of the refrigeration system. The concept of “Shaftwork Targeting” from Pinch Analysis is extended to encompass the design of the entire process. This allows the designer to identify the refrigeration shaftwork benefit related to individual process units thus obtaining “process shaftwork targets” ahead of design. The overall procedure commences with the identification of appropriate column modifications using the concept of “Column Targeting”. The concept of “process shaftwork targeting” is then used to establish the net shaftwork benefit which results from any column modifications. This benefit is traded off against the capital cost of the column modifications thereby enabling the designer to preoptimise distillation column ahead of design. This pre-optimlsation by-passes the usual repeated column and refrigeration system simulations. Finally, the column modifications are “fine tuned” incorporating the actual choice of refrigeration levels and heat exchanger network (HEN) configuration. The refrigeration system and the HEN are also optimised at this final stage. The overall procedure systematically modifies each of the design components ensuring that promising design options are easily identified at an early stage and all major design options are considered. The methodology has been tested on several ethylene and LNG applications yielding an average of 15% shaftwork savings in addition to the savings obtained through established Pinch Analysis procedures.