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A handy method for estimating the particle concentration distribution in FCC risers using a gamma-ray transmission technique

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Petroleum Science 2014年第2期11卷 318-322页

作者： Liu Xiaocheng Wei Yaodong Song Jianfei State Key Laboratory of Heavy Oil Processing China University of Petroleum

A handy gamma-ray transmission method for estimating the particle concentration distribution in a fluid catalytic cracking （FCC） riser is proposed. The method is based on an empirical correlation ε（r）= ε-（0.191＋φ25＋3φ11）, which has only one unknown parameter y, hence only one single-beam experimental result is enough to estimate the particle concentration distribution in the riser. In order to verify the feasibility of this method, the particle concentrations of three cross-sections of the laboratory riser were measured and the distribution profiles were compared with those reported in the literature. Furthermore, by comparing other gamma-ray function methods applied in the measurement of risers, this method has distinct advantages, such as the device is simple and has no moving parts, the measurement is rapid, and the safety is high because only one gamma-ray beam is used. Therefore, the method has promising applications in estimating particle concentrations or monitoring operation conditions of risers.

关键词： Gamma-ray riser FCC catalyst concentration measurement

Fully Coupled Effects of Hull,Mooring and risers Model in Time Domain Based on An Innovative Deep Draft Multi-Spar

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China Ocean Engineering 2010年第2期24卷 219-233页

作者：李彬彬欧进萍滕斌 School of Civil Engineering Harbin Institute of Technology School of Civil & Hydraulic Engineering Dalian University of Technology

The coupled hull, mooring and riser analysis techniques in time domain are widely recognized as the unique approach to predict the accurate global motions. However, these complex issues have not been perfectly solved due to a large number of nonlinear factors, e.g. forces nonlinearity, mooring nonlinearity, motion nonlinearity and so on. This paper investigates the coupled effects through the numerical uncoupled model, mooring coupled model and fully coupled model accounting mooring and risers based on a novel deep draft multi-spar which is especially designed for deepwater in 2009. The numerical static-offset, free-decay, wind-action tests are executed, and finally three hours simulations are conducted under 100-year return period of GOM conditions involving wave, wind and current actions. The damping contributions, response characteristics and mooring line tensions are emphatically studied.

关键词： coupled analysis Spar platform nonlinear hull mooring riser time domain

Thermal stress analysis method considering geometric effect of risers in sand mold casting process

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China Foundry 2014年第6期11卷 531-536页

作者： S.Y.Kwak H.Y.Hwang C.Cho e-Design R&D Group Korea Institute of Industrial Technology (KITECH) Department of Virtual Engineering Korea University of Science and Technology(UST) Department of Mechanical Engineering Inha University

Solidif ication and f luid f low analysis using computer simulation is a current common practice. There is also a high demand for thermal stress analysis in the casting process because casting engineers want to control the defects related to thermal stresses, such as large deformation and crack generation during casting. The riser system is an essential part of preventing the shrinkage defects in the casting process, and it has a great inf luence on thermal phenomena. The analysis domain is dramatically expanded by attaching the riser system to a casting product due to its large volume, and it makes FEM mesh generation diff icult. However, it is diff icult to study and solve the above proposed problem caused by riser system using traditional analysis methods which use single numerical method such as FEM or FDM. In this paper, some research information is presented on the effects of the riser system on thermal stress analysis using a FDM/FEM hybrid method in the casting process simulation. The results show the optimal conditions for stress analysis of the riser model in order to save computation time and memory resources.

关键词： thermal stress sand mold casting riser numerical analysis hybrid method simulation

TLP平台张力筋与顶张紧立管动态响应的数值和实验研究

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Journal of Marine Science and Application 2022年第4期21卷 177-191页

作者：康庄刘光兴李少杰常瑞隋海波 College of Shipbuilding Engineering Harbin Engineering UniversityHarbin 150001China Office of Planning and Investment Saodo UniversityHai DuongVietnam

In this study,the dynamics of the tendon/top tension riser(TTR)system of a tension-leg platform(TLP)are investigated through an experiment and by using absolute nodal coordinate formulation(ANCF).First,the model test of the TLP system is conducted in the water tank of Harbin Engineering University to examine the motion response of the TLP and the dynamic response characteristics of the tendon and *** test scale ratio is set to 1:***,on the basis of the ANCF,the stiffness,external load,and mass matrices of the element are deduced to establish the motion equation of the tendon/***,the static and dynamic characteristics of the tendon/TTR system of TLP are analyzed systematically by using the ANCF *** results are compared with commercial software and test *** motion response of tendon/TTR is affected by the TLP movement and environmental load *** analysis proves the effectiveness and accuracy of the ANCF method despite the low number of riser units,suggesting the superiority of the ANCF method for calculating the dynamics of tendon/riser in the field of ocean engineering.

关键词： Absolute nodal coordinate formulation Model test Tendon riser Tension-leg platform

Fischer-Tropsch wax catalytic cracking for the production of low olefin and high octane number gasoline: Process optimization and heat effect calculation

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Petroleum Science 2023年第2期20卷 1255-1265页

作者： Mei Yang Gang Wang Jian-Nian Han Cheng-Di Gao Jin-Sen Gao State Key Laboratory of Heavy Oil Processing College of Chemical Engineering and and EnvironmentChina University of PetroleumBeijing 102249China College of Science China University of PetroleumBeijing 102249China

To produce low olefin gasoline with high octane number by Fischer-Tropsch (F-T) wax fluid catalytic cracking (FCC) process, operating conditions optimization were carried out in the pilot-scale riser and turbulent fluidized bed (TFB) FCC unit. The experimental results in the riser indicated that under the condition of low reaction temperature and regenerated catalyst temperature, large catalyst-to-oil weight ratio (C/O) and long reaction time, the gasoline olefin content could be reduced to 20.28 wt%, but there is large octane number loss owing to a great loss in high octane number olefin. Therefore, a novel FCC process using the TFB reactor was proposed to strengthen the aromatization reaction. The reaction performance of TFB reactor were investigated. The result demonstrated that the TFB reactor has more significant effect in reducing olefins and improving aromatics. At the expense of certain gasoline yield, the gasoline olefin content reduced to 23.70 wt%, aromatics content could increase to 26.79 wt% and the RON was up to 91.0. The comparison of reactor structure and fluidization demonstrated that the TFB reactor has higher catalyst bed density. The reaction heat and coke combustion heat was calculated indicating the feasibility of its industrial application of the TFB process.

关键词： Fischer-Tropsch wax Catalytic cracking riser TFB Gasoline olefin Reaction heat

New Agri-Silvo-Pastoral Model Utilizing Terrace riserEnhancing Crop and Livestock Production Developed inNepal

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Journal of Agricultural Science and Technology(A) 2019年第6期9卷 371-389页

作者： Barakoti Tanka Prasad Sah Raj Kumar Agricultural Research Station Nepal Agricultural Research CouncilDhankuta 56800PakhribasNepal

Twelve fodder species with maize (Zea mays) and millet (Eleusine coracana) were evaluated under agri-silvo-pastoral system along the Terrace risers (T-risers) of cropping land in the Agricultural Research Station Pakhribas, Nepal. Major aim of innovative agroforestry experiment designed and tested first time in Nepal was to utilize one-third land in risers of cropping terraces due to limited lands of smallholders to produce green fodders needed for livestock. Trees were planted at 1.5 m on the terrace edges and ground fodders at 30-50 cm on the risers. Trees were not allowed to grow tall to avoid shade effect on crops grown in terraces. They were felled at breast height in second year growing coppices for fodder. The results showed higher survival (76% to 100%), growth (1-3 m high) and yield of improved forages and fodder trees indicating potential for cultivation on T-risers. Dry matter (DM) of tree fodders varied 31%-49%, and ground fodders 19%-32%. DM yields ranged 3.0 t/ha (Stylosanthes guanensis) to 26.5 t/ha (Pennisetum purpureum). Combined effects of fodder species on major hill crops, maize and finger millet growth, yield and other attributes were monitored in the terraces. Most mean data were significant and at par between the treatments. Better combinations of tree and ground fodders for higher grain and stover yields (3.1 t/ha and 3.4 t/ha, respectively) of maize were Grewia optiva/Thysalonaema maxima, Desmodium intortum, Ficus auriculata/Setaria anceps, D. intortum (2.7 t/ha and 3.3 t/ha, respectively). Promising combinations for finger millet growth and yields (2-3 t/ha) were G. optiva/T. maxima, Bauhinia purpurea/S. anceps, F. semicordata/P. cetaceum. Soil analysis result showed positive impact of fodders on the risers where organic matter was highly increased after three years. Farmers and stakeholders also evaluated this technology that has been successful and recommended for similar ecological regions.

关键词： Terrace riser fodder trees forage species maize and millet agri-silvo-pastoral system new model.

水下压缩空气储能系统柔性立管响应特性分析（英文）

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Journal of Marine Science and Application 2019年第3期18卷 353-365页

作者：胡博王志文度红望 Rupp Carriveau David S.K.Ting 熊伟王祖温 Institute of Ship Electromechanical Equipment Dalian Maritime UniversityDalian 116026China Turbulence and Energy Laboratory Ed Lumley Centre for Engineering InnovationUniversity of WindsorWindsorOntario N9B 3P4Canada

With the rapid development of marine renewable energy technologies, the demand to mitigate the fluctuation of variable generators with energy storage technologies continues to increase. Offshore compressed air energy storage (OCAES) is a novel flexible-scale energy storage technology that is suitable for marine renewable energy storage in coastal cities, islands, offshore platforms, and offshore renewable energy farms. For deep-water applications, a marine riser is necessary for connecting floating platforms and subsea systems. Thus, the response characteristics of marine risers are of great importance for the stability and safety of the entire OCAES system. In this study, numerical models of two kinds of flexible risers, namely, catenary riser and lazy wave riser, are established in OrcaFlex software. The static and dynamic characteristics of the catenary and the lazy wave risers are analyzed under different environment conditions and internal pressure levels. A sensitivity analysis of the main parameters affecting the lazy wave riser is also conducted. Results show that the structure of the lazy wave riser is more complex than the catenary riser;nevertheless, the former presents better response performance.

关键词： Offshore compressed air energy storage Flexible riser Marine energy Catenary Lazy wave Sensitivity analysis

Influence of separator control on the characteristics of severe slugging flow

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Petroleum Science 2014年第2期11卷 300-307页

作者： Luo Xiaoming He Limin Liu Xinye Lü Yuling College of Pipeline and Civil Engineering China University of Petroleum

Due to the special structure of offshore multiphase pipes, it is easy for severe slugging to occur in the riser at low gas-liquid velocity. Violent pressure fluctuations and dramatic changes of flow rate are the main characteristics of severe slugging, leading to the risk of serious damage. In this paper, the separator control is adopted to accurately control the separator liquid level and pressure under severe slugging flow conditions. This indicates that the separator liquid level control alone does not have a significant impact on the upstream flow, but it is beneficial for normal operation and pressure control of the separator. As the separator pressure increases, the peak pressure in the riser apparently diminishes, and the amplitude of pressure fluctuation gradually decreases, which means that severe slugging is inhibited. During the slug blowing out, the gas/liquid slipping in the riser intensifies. The long gas plug quickly flows through the riser, and then tends to morph into short and slowly flowing gas bubbles. The elimination effect of the pressure control strategy on severe slugging is related to the relative rate of the superficial gas/liquid flow.

关键词： Multiphase flow severe slugging separator control riser

Insulation effect of air cavity in sand mold using 3D printing technology

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China Foundry 2018年第1期15卷 37-43页

作者： Cheng-yang Deng Jin-wu Kang Hao-long Shangguan Tao Huang Xiao-peng Zhang Yong-yi Hu Tian-you Huang School of Materials Science and Engineering Tsinghua University Key Laboratory for Advanced Materials Processing Technology Ministryof Education Beijing China Beijing DRUCK Technology Development Co. Ltd. China

The insulation effect of the air cavity surrounding the riser in a 3D printed sand mold was studied. The influence of the air cavity on heat flux was theoretically analyzed. The results demonstrated that the heat flux of the air cavity in the 3D printed sand mold was significantly less than that of resin-bonded sand. The insulation effect of the air cavity in sand molds for a cylinder casting and a stress-frame casting were simulated using software COMSOL. The results illustrated that the air cavity could be used to insulate the riser and it was more suitable for a lower melting point metal casting. An air cavity with 10-15 mm width and 5-10 mm away from the riser can significantly prolong the solidification of the riser by over 10%. Meanwhile, the sand mold for the stressframe was made by 3D printing technology and poured with aluminum alloy A356 melt. The experiment results showed that the presence of the air cavity led to a 12.5% increase of the solidification time of its riser.

关键词： 3D printing sand mold air cavity insulation effect riser