CFD modelling of methane dispersion from buried pipeline leaks: experimental validation and hazard distance estimation

The safe operation of buried pipelines necessitates an understanding of potential leak dynamics and the subsequent formation of flammable clouds defining hazard distances. This paper presents a computational fluid dynamics (CFD) model and its validation against experimental data on the dispersion of methane through a sand layer of 100 mm thickness to the atmosphere. A leak orifice diameter of 4 mm was considered for pipeline gauge pressures in the range of 10 to 300 kPa. This study describes the methane propagation in time through the sand and the development of the flammable cloud in the atmosphere. The simulations demonstrate a high degree of accuracy in capturing the transient behaviour of methane propagation in the sand and dispersion in the atmosphere when compared with a 60 s experiment. The model was applied to predict the development and maximum spread of the flammable cloud and hazard distances are presented. The simulations provide insight into the development of the flammable cloud. The validated CFD model can serve as a predictive tool for hazard distance estimation in case of buried leaks, inform safer pipeline design and improve emergency response strategies for gas leaks

Blending Hydrogen into Natural Gas Pipeline Networks. A Review of Key Issues

The United States has 11 distinct natural gas pipeline corridors: five originate in the Southwest, four deliver natural gas from Canada, and two extend from the Rocky Mountain region. This study assesses the potential to deliver hydrogen through the existing natural gas pipeline network as a hydrogen and natural gas mixture to defray the cost of building dedicated hydrogen pipelines

The Intelligent Crude Oil Anti-theft System Based on IoT Under Different Scenarios

AbstractOil theft always results in huge economic loss, human casualties, and extremely environmental pollution especially when the leaks from crude oil pipeline are not detected and repaired timely. In this paper, we focus on how to detect and monitor abnormal noise and vibration beforehand or in real time by the Internet of Things (IoT). Firstly, the diversities of crude oil theft and the difficulties of oil anti-theft are analyzed in China, and the requirement analysis of the IoT application is stated. Secondly, the intelligent anti-theft system based on the IoT is planned and designed for crude oil transportation by tank trucks and by oil pipelines according to the current situation in China. Thirdly, the problems of anti-theft system implementation are discussed, and the suggestions and advice are put forward to ensure that the system can be implemented successfully. The intelligent anti-theft system application can not only stop oil theft timely, but also prevent oil mice from stealing crude oil beforehand

INVESTIGATION ON BIOGAS DISPERSION USING COMPUTATIONAL FLUID DYNAMICS MODELING

Biogas technology is developing rapidly in the recent year due to increment of dependency in human on the renewable energy. Process safety of biogas plant is one of the current issues which is very critical for the process operations. Several cases of fire and explosion related to biofuel plant have alarmed the industries on the potential hazard from current running biogas plant. Limited failure data is available for consequence risk analysis to understand scenario of biogas dispersion. Thus, a study is carried out on the dispersion model of biogas to show the behavior of biogas from pressurized release into the environment by using Computational Fluid Dynamics (CFD) modeling. CFD is a branch of fluid mechanics that uses numerical method and algorithm to solve the problem which involves fluid flow. The code used is CFD-FLUENT by ANSYS Company. CFD dispersion model developed is validated against IP Model Code and PHAST which shows close agreement with deviation at 18% and is acceptable. Gas dispersion study is based on influence of wind speed and the presence of obstacle. Lower wind speed will pose higher risk of fire and explosion due to stable atmospheric turbulence. Presence of obstacle will cause the gas to be easily trapped and create flammable region. Biogas shows shorter hazardous distance as compared to that of methane gas. It can be explained as the lower composition of methane in biogas. Thus, biogas is less flammable than pure methane gas

An advanced framework for leakage risk assessment of hydrogen refueling stations using interval-valued spherical fuzzy sets (IV-SFS)

The extensive population growth calls for substantial studies on sustainable development in urban areas. Thus, it is vital for cities to be resilient to new situations and adequately manage the changes. Investing in renewable and green energy, including high-tech hydrogen infrastructure, is crucial for sustainable economic progress and for preserving environmental quality. However, implementing new technology needs an effective and efficient risk assessment investigation to minimize the risk to an acceptable level or ALARP (As low as reasonably practicable). The present study proposes an advanced decision-making framework to manage the risk of hydrogen refueling station leakage by adopting the Bow-tie analysis and Interval-Value Spherical Fuzzy Sets to properly deal with the subjectivity of the risk assessment process. The outcomes of the case study illustrate the causality of hydrogen refueling stations' undesired events and enhance the decision-maker's thoughts about risk management under uncertainty. According to the findings, jet fire is a more likely accident in the case of liquid hydrogen leakage. Furthermore, equipment failure has been recognized as the most likely cause of hydrogen leakage. Thus, in order to maintain the reliability of liquid hydrogen refueling stations, it is crucial that decision-makers develop a trustworthy safety management system that integrates a variety of risk mitigation measures including asset management strategies

Construction of Hydrogen Safety Evaluation Model Based on Analytic Hierarchy Process (AHP)

With the large consumption of traditional primary energy, hydrogen as a clean and renewable energy has been widely studied by scholars around the world. Hydrogen is mainly used in hydrogen internal combustion engine and hydrogen fuel cell. Hydrogen internal combustion engine is the direct combustion of hydrogen as fuel, with the advantages of easy use. Alternatively, hydrogen fuel cell converts the chemical energy of hydrogen into electrical energy by electrochemical reaction, which has the advantages of high efficiency and zero pollution. Regardless of the use method, the safety of hydrogen use needs to be considered. However, in the whole life cycle of hydrogen, the process from hydrogen production to the use of hydrogen in automobiles is extremely complex. There are many factors affecting the safety of hydrogen use, and a single factor cannot be used as an evaluation. In order to make the evaluation of hydrogen safety more complete and accurate, the weight of four primary evaluation indexes and eight secondary evaluation indexes affecting hydrogen safety is determined by analytic hierarchy process, and a reliable hydrogen safety evaluation model is established.Citation: Xu, J., Wang, M., and Guo, P. (2022). Construction of Hydrogen Safety Evaluation Model Based on Analytic Hierarchy Process (AHP). Trends in Renewable Energy, 8(2), 84-95. DOI: http://dx.doi.org/10.17737/tre.2022.8.2.0014