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The exploration on the microscale transport phenomena is of great significance to understand the mechanism of microscale mixing and chemical reaction in a rotating packed bed (RPB). In this paper, numerical investigation is carried out and compared with the experimental results. Two different scale reaction models are applied to simulate and the numerical result is in reasonable agreement with the experimental results. The fluid flow and the species transfer with a competitive and consecutive reaction are studied to obtain the evolution of the segregation index and flow field. Each environment changes and is updated continuously with the liquid film flowing outward, and the micromixing and reaction are influenced by the fractions p 1 and p 2 of different environments. It is evidenced that different factors such as rotational speeds, volume ratios and initial mixing concentration impose considerable influences on the micromixing and reaction processes. The micromixing time ranges about 5.2 × 10 −2 –1 × 10 −3 ms showing that micromixing performance in RPB is much better. The main product and by-product appear different evolution pattern along the package wires, which provide guideline for the optimization of RPB structure. The optimization on the RPB structure is provided and the simulation results clarify a deeper understanding on the micromixing and reaction features in RPB. [ABSTRACT FROM AUTHOR]

Highlights: [•] Behavior of H2S-containing natural gas exhibits appearance of neutral gas by CFD. [•] The poisoning hazards of H2S by gas pipeline releases are successfully estimated. [•] An assessment method for available safe egress time is proposed. [Copyright &y& Elsevier]

Abstract: The storage capacity of natural gas containing hydrogen sulfide is large and widely distributed. Release of hydrogen sulfide-bearing natural gas from the pipelines imposes serious threats to the lives and property near the leakage source. Based on a large number of accident statistics and analysis and experiment results, a new risk analysis method for hydrogen sulfide poisoning is proposed, which takes into account of the probability of risk, the scope of damage and dose-response model. A suitable leakage source model is established, and according to the leakage scenario, Gaussian plume model is chosen to estimate the diffusion extent of well blowout of natural gas containing sulfide hydrogen. Three leakage scenarios of Sichuan-Eastern Gas Transportation Project are analyzed based on the historical data of European Gas Pipeline Incident Data Group and BG Transco, including individual risk analysis and societal risk analysis. The corresponding social risk curves are plotted and hazardous areas based on different hole diameters are classified. Societal risk varies significantly with the factors such as population density, probability of death and so on. With the acceptable risk criteria published by HSE taken into account, individual risk and societal risk of the leakage scenarios in this paper are found all unacceptable. The proposed method can provide supports for the safety management and maintenance of natural gas pipeline as well as evacuation after accidents happen. [Copyright &y& Elsevier]

• Developed real-time hybrid model (RTHM) tests to reproduce Saige building vibration incident. • Developed RTHM testing system that includes the loading system, instrumentations, and the delay compensation component. • Wind loads tests of the masts were first carried out show that the dynamic characteristics of scaled mast models were conserved. • RTHM results demonstrate the capability of the developed testing method to reproduce the Saige building abnormal vibration. In May 2021, the 72-story Shenzhen Saige building experienced abnormal vibration that was strongly felt on many floors and triggered social panic. The tower was therefore closed for more than 2 months resulting in huge economic losses. A preliminary study consisting of field resonant excitation tests and a series of numerical simulations were carried out. It was concluded that the wind loads provoked the higher modes of the building vibration. Specifically, the vibration of the mast, which is located at the building top, induced this abnormal vibration. To validate this conclusion, real-time hybrid model (RTHM) tests was developed to reproduce this building vibration incident. This paper presents the details of the validation RTHM tests including testing design and result discussions. Structural vibration parameters obtained from the field tests were used in the numerical substructure building model, and the experimental substructures were the two scaled down mast models (the cantilever beam section of the masts). During RTHM test, the restoring force of the experimental substructure due to real wind loads induced by an air fan was measured and used in the numerical simulation to compute interface motions. A shaking table was then used to impose the interface motion back to the bottom of the mast model to reproduce the abnormal vibration incident. The demonstrated ability of the developed RTHM testing method to reproduce the resonant phenomenon of the wind-induced tower vibration provides an alternative experimental method to study vibration responses of high-rise buildings in future. [ABSTRACT FROM AUTHOR]

Due to the ineffectiveness in removing cyclic sulfur compounds (S-compounds) and nitrogen compounds (N-compounds) such as thiophene (TS), dibenzothiophene (DBT), carbazole, pyridine and their derivatives from fuel oils, the traditional hydrodesulfurization and hydrodenitrogenation processes are facing some challenges especially now in the wake of sterner regulation of S-/N-content in fuel oils. This work demonstrates that some acidic ionic liquids (ILs) are capable of extracting cyclic S-/N-compounds particularly the basic N-species from fuel oils. Both Lewis acidic ILs 1-butyl-3-methylimidazolium chloride/ZnCl2 ([Bmim]Cl/ZnCl2) and [Bmim]Cl/2ZnCl2 as well as Brφnsted acidic ILs [Bmim]HSO4 and [Hmim]HSO4 are used to extract TS, DBT, carbazole and pyridine from their hexane (model gasoline) or octane (model diesel fuel) mixtures. Typically, 93.8% TS removal (S-content drops from 500 ppm to 31 ppm) and 95.9% DBT removal (S-content from 516 ppm to 21 ppm) by [Bmim]Cl/ZnCl2 after 6-stage extraction are obtained at 25 °C, 1:1(w/w)IL:oil, 30 min; while 93.8% carbazole removal (N-content from 279 ppm to 17 ppm) and 97.8% pyridine removal (N-content from 495 ppm to 11 ppm) are realized after only one stage extraction and the N-content is undetectable after 2-stage extraction. [Bmim]Cl/ZnCl2 is selected as a representative IL to undergo a series of parallel experiments to determine the influence of extraction time, temperature, IL:oil mass ratio and multi-stage extraction on S-/N-removal efficiency. The mutual solubility of [Bmim]Cl/ZnCl2 in fuel oil as well as IL recycling is also performed. [ABSTRACT FROM AUTHOR]