scholarly journals Structural optimization of baffle internals for fast particle pyrolysis in a downer reactor using the discrete element method

Clean Energy ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 167-179
Author(s):  
Bing Liu
Keyword(s):  
Discrete Element Method ◽  
Structural Optimization ◽  
Heat Carrier ◽  
Process Design ◽  
Slope Angle ◽  
Discrete Element ◽  
Coal Pyrolysis ◽  
The Mean ◽  
Downer Reactor ◽  
Element Method

Abstract The structural optimization of baffle internals for fast pyrolysis of coal with particulate mixing and heat transfer in a downer reactor using the discrete element method (DEM) has been investigated in this research. The pyrolysis terminal temperature at the exit of the downer reactor is not only decided by the volume-feeding-rate ratio of the coal to the sand, but also is affected by the inner structural design of the baffle internals in the downer reactor. As presented in the previous publication of the author, the inhibition from the baffle internals in a downer reactor can improve the particulate-mixing degree and heat carrier, and increase the mean residence time of the coal and heat-carrier particles in the downer reactor. The structure of the baffle internals in the downer reactor mentioned in this research can be optimized by the independently developed 3D soft-sphere model of the DEM programme of a 40-mm baffle length, a 30° baffle-slope angle and at least four baffles designed in the downer reactor, which is beneficial for the process design of coal pyrolysis with a heat carrier in the downer reactor.

scholarly journals Complex Failure Simulation of Underinclined Shale Slope Based on Discrete Element Method

2020 ◽  
Vol 24 (1) ◽  
pp. 83-89
Author(s):  
Bin Li ◽  
Da Huang
Keyword(s):  
Discrete Element Method ◽  
Slope Failure ◽  
Slope Angle ◽  
Soft Rock ◽  
Discrete Element ◽  
Failure Patterns ◽  
Site Investigations ◽  
Dip Angle ◽  
Different Parts ◽  
Element Method

A landslide occurred in the cut slope located in Chongqing west railway station, this slope belongs to a under-dip shale slope, which means that its bedding dip angle is larger than slope angle and it is comprised of soft rock. Some on-site investigations have been made to explore the deformation characteristics of this slope, the outcome suggested that sliding, buckling and toppling deformation existed at its different parts. To elucidate the complex failure mechanism exhibited by the under-dip slope under the long-term influence of gravity and material deterioration, the discrete element method has been employed in simulations. The simulated failure patterns have proven to be in strong agreement with the actual slope failure. This study suggests that sliding, buckling and toppling occur at different parts of the studied slope in sequence.

scholarly journals Dynamic Modeling of a Vibrating Screen Considering the Ore Inertia and Force of the Ore over the Screen Calculated with Discrete Element Method

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Manuel Moncada M. ◽  
Cristian G. Rodríguez
Keyword(s):  
Discrete Element Method ◽  
Dynamic Model ◽  
Dynamic Models ◽  
Adhesion Force ◽  
Angular Displacement ◽  
Slope Angle ◽  
Discrete Element ◽  
Vibrating Screen ◽  
Linear Dynamic ◽  
Element Method

Vibrating screens are critical machines used for size classification in mineral processing. Their proper operation, including accurate vibration movement and slope angle, can provide the benefits of energy savings and cost reductions in the screening process and the whole mining process. Dynamic models of the vibrating screen movement available in the literature do not simulate ore motion or its interaction with screen decks. The discrete element method (DEM) allows for the calculation of the dynamic of the ore. In this paper, two 2D three-degrees-of-freedom dynamic models for a vibrating screen are tested, using linear and nonlinear approaches for angular displacement. These models consider the inertia of the ore and the ore force calculated with DEM. A double-deck linear motion vibrating screen is simulated using the DEM software LIGGGTHS. DEM is used to obtain the ore parameters in the steady state and the force on the screen decks. Two cases are compared: Case 1 considers the ore as moving together with the vibrating screen, and Case 2 considers the ore force on the screen deck as calculated by DEM. Simulations are carried out with data for an industrial vibrating screen used in copper mining. The force over the screen is significantly different between the cases. Case 1 produces a force that is unrealistic because the ore cannot produce a high-amplitude adhesion force over the screen decks. In Case 2, no adhesion force acts between the ore and deck. It is concluded that the linear dynamic model used in Case 2 is adequate to evaluate the influence of the ore on the movement of the vibrating screen. The linear dynamic model considering the force as in Case 1 can be used to simulate a vibrating screen, as long as a correct calibration parameter is included to obtain an accurate motion amplitude.

scholarly journals VERIFICATION OF ROCKFALL MODEL, BASED ON THE DISCRETE ELEMENT METHOD

2016 ◽  
Author(s):  
А.Г. Кусраев ◽  
Д.Г. Минасян ◽  
Н.С. Орлова ◽  
Д.Г. Пантилеев ◽  
Ш.С. Хубежты
Keyword(s):  
Experimental Investigation ◽  
Discrete Element Method ◽  
Theoretical Investigation ◽  
Slope Angle ◽  
Discrete Element ◽  
Laboratory Equipment ◽  
Horizontal Section ◽  
Affected Area ◽  
Model Based ◽  
Element Method

Исследовалось движение обвала по склону, сопряженному с горизонтальным участком. Теоретическое исследование осуществлялось с использованием модели на основе метода дискретных элементов. Для верификации модели был проведен эксперимент на лабораторной установке. Представлено сравнение дальности пробега обвальной массы в зависимости от крутизны склона в экспериментах и расчетах. Получено удовлетворительное совпадение результатов The rockfall movement of the slope, which is associated with the horizontal section, was investigated. The theoretical investigation was performed using model, based on the Discrete element method. The experimental investigation was performed using laboratory equipment. Comparison between the experiment results and calculations were presented. Numerical calculations of the affected area of rockfall, performed for various values of the slope angle to horizontal surface, satisfactorily describe experiments

Discrete element method to model cracking for two layer systems

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 101-108
Author(s):  
Daniel Varney ◽  
Douglas Bousfield
Keyword(s):  
Discrete Element Method ◽  
Flexural Modulus ◽  
Single Layer ◽  
Discrete Element ◽  
Flexural Stress ◽  
Layer System ◽  
Three Point Bending ◽  
Moving Force ◽  
Coating Layers ◽  
Element Method

Cracking at the fold is a serious issue for many grades of coated paper and coated board. Some recent work has suggested methods to minimize this problem by using two or more coating layers of different properties. A discrete element method (DEM) has been used to model deformation events for single layer coating systems such as in-plain and out-of-plain tension, three-point bending, and a novel moving force picking simulation, but nothing has been reported related to multiple coating layers. In this paper, a DEM model has been expanded to predict the three-point bending response of a two-layer system. The main factors evaluated include the use of different binder systems in each layer and the ratio of the bottom and top layer weights. As in the past, the properties of the binder and the binder concentration are input parameters. The model can predict crack formation that is a function of these two sets of factors. In addition, the model can predict the flexural modulus, the maximum flexural stress, and the strain-at-failure. The predictions are qualitatively compared with experimental results reported in the literature.

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