scholarly journals Numerical Analysis on Erosion and Optimization of a Blast Furnace Main Trough

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4851
Author(s):  
Hao Yao ◽  
Huiting Chen ◽  
Yao Ge ◽  
Han Wei ◽  
Ying Li ◽  
...  
Keyword(s):  
Blast Furnace ◽  
High Efficiency ◽  
Low Cost ◽  
Continuous Production ◽  
Hot Metal ◽  
Main Trough ◽  
Impact Position ◽  
Refractory Life ◽  
Volume Method ◽  
The Impact

The main trough of a blast furnace (BF) is a main passage for hot metal and molten slag transportation from the taphole to the torpedo and the slag handling. Its appropriate working status and controlled erosion ensure a safe, stable, high-efficiency and low-cost continuous production of hot metal. In this work, the tapping process of a main trough of a BF in the east of China was numerically studied with the help of a CFD library written in C++, called OpenFOAM, based on the use of the Finite Volume Method (FVM). The results show that turbulence intensity downstream of the hot metal impact position becomes weaker and the turbulence area becomes larger in the main trough. During the tapping, thermal stress of wall refractory reaches the maximum value of 1.7 × 107 Pa at the 4 m position in the main trough. Furthermore, baffles in the main trough placed between 5.8 m and 6.2 m were found to control and reduce the impact of the turbulence on the refractory life. The metal flowrate upstream of the baffles can be decreased by 6%, and the flow velocity on the upper sidewall and bottom wall decrease by 9% and 7%, respectively, compared with the base model. By using baffles, the minimum fatigue life of the refractory in the main trough increases by 15 tappings compared with the base model, so the period between the maintenance stops can be prolonged by about 2 days.

scholarly journals The Impact and Empirical Analysis of the Development Level of E-commerce Industry on China’s Export Trade

2021 ◽  
Vol 235 ◽  
pp. 02046
Author(s):  
Chun Feng ◽  
Fei Lei ◽  
Zhijun Luo
Keyword(s):  
High Efficiency ◽  
Positive Impact ◽  
Low Cost ◽  
Status Quo ◽  
Export Trade ◽  
Empirical Methods ◽  
Existing Problems ◽  
Development Level ◽  
The Status ◽  
The Impact

With its advantages of low cost and high efficiency, e-commerce is not only favored by ordinary consumers, but also effectively promotes SMEs to find business opportunities and win the market. This article starts with the development scale of China’s e-commerce industry and the status quo of export trade, and measures the overall index of China’s e-commerce industry development level from 2008 to 2018 through empirical methods to analyze its impact on China’s export trade. The results show that the development level of the e-commerce industry has a significant positive impact on China’s export trade. Finally, it analyzes the existing problems in the development of China’s e-commerce industry.

scholarly journals Economics of an Additive Manufactured Heat Exchanger for Concentrating Solar Power

2022 ◽  
Author(s):  
Tracey Ziev ◽  
Erfan Rasouli ◽  
Ines Noelly-Tano ◽  
Ziheng Wu ◽  
Srujana Yarasi Rao ◽  
...  
Keyword(s):  
High Efficiency ◽  
Solar Power ◽  
Cost Model ◽  
Low Cost ◽  
Operating Conditions ◽  
Concentrated Solar Power ◽  
Future Technologies ◽  
The Cost ◽  
Alternative Current ◽  
The Impact

Developing low cost, high efficiency heat exchangers (HX) for application in concentrated solar power (CSP) is critical to reducing CSP costs. However, the extreme operating conditions in CSP systems present a challenge for typical high efficiency HX manufacturing processes. We describe a process-based cost model (PBCM) to estimate the cost of fabricating an HX for this application using additive manufacturing (AM). The PBCM is designed to assess the effectiveness of different designs, processes choices, and manufacturing innovations to reduce HX cost. We describe HX design and AM process modifications that reduce HX cost from a baseline of$780/kW-thto$570/kW-th. We further evaluate the impact of alternative current and potential future technologies on HX cost, and identify a pathway to further reduce HX cost to$270/kW-th.

Numerical Analysis on the Refractory Wear of the Blast Furnace Main Trough

2014 ◽  
Vol 92 ◽  
pp. 294-300 ◽  
Author(s):  
Ca Min Chang ◽  
Yon Sen Lin ◽  
Chien Nan Pan ◽  
Wen Tung Cheng
Keyword(s):  
Shear Stress ◽  
Blast Furnace ◽  
Erosion Rate ◽  
Three Dimensional ◽  
Stress Profile ◽  
Refractory Wear ◽  
Main Trough ◽  
Split Operator ◽  
Shear Stress Profile ◽  
Volume Method

This study aims to numerically analyze the refractory wear of the blast furnace main trough. The three dimensional transient Navier-Stocks equation associated with the volume of fluid (VOF) was developed to describe the flow fields of air, molten iron and slag in the main trough of the blast furnace during tapping process; and then solved by the finite volume method (FVM) subject to the pressure implicit with split operator (PSIO). Based on the Newton’s law of viscosity, the computed shear stress profile in the impingement region consists with the erosion rate of main trough from the no. 4 blast furnace at China Steel Corporation (CSC BF4). The influence of the tapping angle and the ratio of iron to slag in tapping stream on the wall shear stress of main trough was also examined for the suggestion to minimize the refractory wear of blast furnace main trough in this work.

scholarly journals Influence of Prescribed Burning on a Pinus nigra subsp. Laricio Forest: Heat Transfer and Tree Vitality

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 915
Author(s):  
Lila Ferrat ◽  
Frédéric Morandini ◽  
Gauthier Lapa
Keyword(s):  
Heat Transfer ◽  
Prescribed Burning ◽  
High Efficiency ◽  
Low Cost ◽  
Fire Spread ◽  
Pinus Nigra ◽  
Critical Threshold ◽  
Long Term Effects ◽  
Tree Vitality ◽  
The Impact

Surface fuel removal is crucial to facilitate the mitigation of severe fires in forests. Prescribed burning is often used by forest managers, thanks to its low cost and high efficiency in hard-to-reach areas. The determination of heat transfer between fires and trees has rarely been carried out on living species and consequently, their long-term effects on tree physiology are still not fully understood. In this study, a multidisciplinary approach was conducted to evaluate the impact of a late spring (June) prescribed burning on a Mediterranean pine forest (Pinus nigra subsp. laricio). The surface fuels consisted of a 656 g m−² needle litter, mixed with a few scattered living herbaceous strata. During the fire spread, measurements of the inner and outer trunk temperatures were made at the base of 12 trees with an average bark thickness of 19.4 ± 7.0 mm. The fireline intensity and flame residence time were in the range of 110–160 kW m−1 and 220–468 s, respectively. Despite a maximum heating rate at the cambial area of 4.37 °C min−1, the temperature of these tissues remained below 60 °C, a critical threshold above which thermal damage will occur. In addition, prior- and post-fire physiological monitoring was performed over a long time period (2.5 years) on 24 trees, using sap flow, chlorophyll fluorescence and gas exchange measurements. All parameters remain highly correlated and indicate that the burned trees did not suffer physiological damage. Moreover, drought resistance strategies were not altered by the prescribed burning. The thermal insulation capability of the bark allowed the functional tissues to experience low heat stress that did not affect tree vitality.

scholarly journals Iterative Learning Method for In-Flight Auto-Tuning of UAV Controllers Based on Basic Sensory Information

2019 ◽  
Vol 9 (4) ◽  
pp. 648 ◽  
Author(s):  
Wojciech Giernacki
Keyword(s):  
Control Systems ◽  
Performance Index ◽  
High Efficiency ◽  
Search Algorithm ◽  
Low Cost ◽  
Sensory Information ◽  
Learning Method ◽  
Comprehensive Description ◽  
Auto Tuning ◽  
The Impact

With an increasing number of multirotor unmanned aerial vehicles (UAVs), solutions supporting the improvement in their precision of operation and safety of autonomous flights are gaining importance. They are particularly crucial in transportation tasks, where control systems are required to provide a stable and controllable flight in various environmental conditions, especially after changing the total mass of the UAV (by adding extra load). In the paper, the problem of using only available basic sensory information for fast, locally best, iterative real-time auto-tuning of parameters of fixed-gain altitude controllers is considered. The machine learning method proposed for this purpose is based on a modified zero-order optimization algorithm (golden-search algorithm) and bootstrapping technique. It has been validated in numerous simulations and real-world experiments in terms of its effectiveness in such aspects as: the impact of environmental disturbances (wind gusts); flight with change in mass; and change of sensory information sources in the auto-tuning procedure. The main advantage of the proposed method is that for the trajectory primitives repeatedly followed by an UAV (for programmed controller gains), the method effectively minimizes the selected performance index (cost function). Such a performance index might, e.g., express indirect requirements about tracking quality and energy expenditure. In the paper, a comprehensive description of the method, as well as a wide discussion of the results obtained from experiments conducted in the AeroLab for a low-cost UAV (Bebop 2), are included. The results have confirmed high efficiency of the method at the expected, low computational complexity.

scholarly journals Updating the Role of Reduced Graphene Oxide Ink on Field Emission Devices in Synergy with Charge Transfer Materials

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 137 ◽  
Author(s):  
Minas Stylianakis ◽  
George Viskadouros ◽  
Christos Polyzoidis ◽  
George Veisakis ◽  
George Kenanakis ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Field Emission ◽  
Large Scale ◽  
High Efficiency ◽  
Low Cost ◽  
Field Enhancement ◽  
Field Emitter ◽  
Reduced Graphene ◽  
The Impact

Hydroiodic acid (HI)-treated reduced graphene oxide (rGO) ink/conductive polymeric composites are considered as promising cold cathodes in terms of high geometrical aspect ratio and low field emission (FE) threshold devices. In this study, four simple, cost-effective, solution-processed approaches for rGO-based field effect emitters were developed, optimized, and compared; rGO layers were coated on (a) n+ doped Si substrate, (b) n+-Si/P3HT:rGO, (c) n+-Si/PCDTBT:rGO, and (d) n+-Si/PCDTBT:PC71BM:rGO composites, respectively. The fabricated emitters were optimized by tailoring the concentration ratios of their preparation and field emission characteristics. In a critical composite ratio, FE performance was remarkably improved compared to the pristine Si, as well as n+-Si/rGO field emitter. In this context, the impact of various materials, such as polymers, fullerene derivatives, as well as different solvents on rGO function reinforcement and consequently on FE performance upon rGO-based composites preparation was investigated. The field emitter consisted of n+-Si/PCDTBT:PC71BM(80%):rGO(20%)/rGO displayed a field enhancement factor of ~2850, with remarkable stability over 20 h and low turn-on field in 0.6 V/μm. High-efficiency graphene-based FE devices realization paves the way towards low-cost, large-scale electron sources development. Finally, the contribution of this hierarchical, composite film morphology was evaluated and discussed.

scholarly journals Application of a blast furnace slag carrier catalyst in flue gas denitration and sulfur resistance

RSC Advances ◽  
2021 ◽  
Vol 11 (25) ◽  
pp. 15036-15043
Author(s):  
Zhang Lei ◽  
Lu Xi ◽  
Qi Lingbo ◽  
Shu Hao ◽  
Jia Yang ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Flue Gas ◽  
Blast Furnace Slag ◽  
High Efficiency ◽  
Low Cost ◽  
Sulfur Resistance ◽  
Furnace Slag

It is an urgent need to develop a new catalyst with high efficiency and low cost.

Effect of slag-remaining operation on dephosphorization based on single-slag converter steelmaking technology

2019 ◽  
Vol 116 (5) ◽  
pp. 504
Author(s):  
Yuxiang Dai ◽  
Jing Li ◽  
Wei Yan ◽  
Shenyang Song
Keyword(s):  
Phosphorus Content ◽  
High Efficiency ◽  
Early Stage ◽  
Low Cost ◽  
Continuous Production ◽  
Converter Steelmaking ◽  
Molten Bath ◽  
Industrial Practice ◽  
The Times ◽  
Steelmaking Technology

During converter steelmaking process, large amounts of slags are generated which take away heat and iron resources from molten bath. The slag-remaining operation is a kind of hot slag recycling. It is that all or most of the slags are left in the converter for next heat during continuous production of several successive heats. The basicity of the remaining slag is about 3, and the content of (FeO) is about 20%.When slag-remaining operation is adopted, it increases the slagging speed in the early stage. Influence of slag-remaining process on the dephosphorization during converter steelmaking was studied through industrial practice and theoretical calculation. The results show that the slag-remaining operation can realize low cost and high efficiency for converter steelmaking. It can reduce the consumption of lime and achieve better dephosphorization effect. But phosphorus content in slag increases gradually with the increase of slag remaining times and the dephosphorization capacity of slag is reduced, which result in the poor dephosphorization of steel. Therefore, the times of slag-remaining should be less than 5 to ensure the dephosphorization of steel.

scholarly journals Numerical Analysis on Flow Behavior of Molten Iron and Slag in Main Trough of Blast Furnace during Tapping Process

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Li Wang ◽  
Chien-Nan Pan ◽  
Wen-Tung Cheng
Keyword(s):  
Blast Furnace ◽  
Separation Efficiency ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Molten Iron ◽  
Three Dimensional Model ◽  
Operation Conditions ◽  
Main Trough ◽  
Iron Losses ◽  
Volume Method

The three-dimensional model was developed according to number 4 of the main trough of blast furnace at China Steel Co. (CSC BF4). The k-ε equations and volume of fluid (VOF) were used for describing the turbulent flow at the impinging zone of trough, indicating fluids of liquid iron, molten slag, and air in the governing equation, respectively, in this paper. The pressure field and velocity profile were then obtained by the finite volume method (FVM) and the pressure implicit with splitting of operators (PISO), respectively, followed by calculating the wall shear stress through Newton’s law of viscosity for validation. Then, the operation conditions and the main trough geometry were numerically examined for the separation efficiency of iron from slag stream. As shown in the results, the molten iron losses associated with the slag can be reduced by increasing the height difference between the slag and iron ports, reducing the tapping rate, and increasing the height of the opening under the skimmer.

Еfficiency increase of powdered coal application at hot metal production and limestone calcination under unstable technology conditions

2020 ◽  
Vol 76 (7) ◽  
pp. 676-690
Author(s):  
Yu. S. Semenov ◽  
A. L. Podkorytov ◽  
V. V. Gorupakha ◽  
I. Yu. Semion ◽  
A. Yu. Orobtsev ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Ferrous Metallurgy ◽  
Gas Flow ◽  
High Efficiency ◽  
Furnace Productivity ◽  
Hot Metal ◽  
Coal Injection ◽  
Powdered Coal ◽  
Limestone Calcination ◽  
Steel Works

Operation of Ukraine ferrous metallurgy under conditions of dependence on import and instability of energy carriers supply, shortage of investments in modernization of production equipment, make the matter of cooperation between steel-works and research organization particularly actual. Basic results of cooperation between Z.I. Nekrasov Institute of Ferrous metallurgy, NAN of Ukraine and Dnepr steel-works in 2017–2019 on blast sfurnace operation pefection and technology of powdered coal injection into rotating limestone calcination furnaces. Results of the finding of the powdered coal optimal consumption shown, which ensure a high efficiency of the coke substitution, reaching of maximum possible blast furnace productivity as well as satisfactory utilization degree of the reducing gas ability. Results of implementation of a complex of measures presented, which ensure a rational distribution of the powdered coal by BF air tuyeres for making the heat conditions of the tuyere zone even by the blast furnace circle. Efficiency of application of technology of joint injection the powdered coal and natural gas was shown, which is achieved by improving the powdered coal combustion conditions in case of increase their mixing degree. Recommendations quoted for blast furnaces starting-up after their idling for a period exceeding the permissible one, without tapping the plug hot metal. The recommendations ensure an accident-free putting a blast furnace into operation followed by reaching planned parameters. Results of usage sensors information, measuring temperature of gas flow above the charge surface presented. The results allow to prove the correction of blast furnace charging mode by an expert module, generating correction impact to support control actions by technological personal. A complex of measures formed to prevent a disturbance of a blast furnace running in case of powdered coal injection in an amount exceeding 140 kg/t of hot metal and without application of special washover materials. The results of efficiency of the mastered technology, envisaging application manganese-bearing materials at a constant base, were shown. Results of diagnostics of workability of the facility for powdered coal injection into rotating limestone calcinating furnace presented, followed by elaboration recommendation on correction parameters of injection facility operation.

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