Guangwu Tang

CFD Study of Gas-Liquid Phase Interaction Inside a Submerged Lance Smelting Furnace for Copper Smelting

Bath smelting technology, such as the submerged lance smelting furnace, is used in the modern copper making industry. The first submerged lance smelting furnace developed by Dongying Fangyuan Nonferrous Metals Co., Ltd has shown potential for high productivity and energy savings. In this study, computational fluid dynamics (CFD) was applied to investigate the current design of the furnace. A three-dimensional multiphase CFD model was developed to study the interaction between injected gas and the liquid bath. The multiphase Eulerian model was used for simulating gas/liquid two-phase flow. The flow pattern in the submerged lance smelting furnace indicated rapid flow development and strong turbulent interactions between the gas and liquid phases. The model was validated based on a water model experiment of the mixing process. Mixing times from the simulation results show good agreement with experimental data. Additionally, based on this model, the gas residence time and liquid copper matte splashing phenomena under varying gas flow rates were investigated.

CFD Modeling of Flow and Chemical Reactions in a Submerged Lance Copper Smelting Furnace

The submerged lance smelting furnace (SLS) for copper smelting has been developed and used by Dongying Fangyuan Nonferrous Metals Co., Ltd. The technology has shown advantages such as high oxygen enrichment, good feed adaptability, short processing time, high SO2 concentration for acid plant, and auto-thermal operation. In this study, computational fluid dynamics (CFD) was used to investigate the gas/matte two-phase flow characteristics and the chemical reactions in the SLS during typical operational conditions. The Eulerian-Eulerian approach was employed to model the phase interactions. The chemical reactions were modeled by calculating the mass transfer coefficients and using the eddy-dissipation model. The simulation was conducted using the commercial software ANSYS Fluent®. The developed CFD model is able to predict the flow, temperature, and species distributions inside the SLS under various operating conditions.

CFD Modeling of A Ladle With Top Stirring Lance

Steel cleanliness is very important for the quality of final products. Stirring ladles have been widely used to ensure the good quality steel produced from liquid iron in steelmaking industry. Proper stirring is crucial for obtaining clean steel. In this study, three-dimensional computational fluid dynamics (CFD) technique is used to study the transient multiphase flow inside a working ladle at a steel plant. The study presents a comparison of three different methods to model multi phase flow, i .e. the volume of fluid (VOF) method, the Eulerian-Eulerian method, and the Eulerian-Lagrangian method. The simulation results are compared with ex perimental data obtained from a working ladle. The best simulation method, which gives the most accurate results within a reasonable amount of computational time, will be applied to optimize operating parameters under various conditions.

CFD Analysis of Blast Furnace Operating Condition Impacts on Operational Efficiency

Blast furnaces are counter-current chemical reactors used to reduce iron ore into liquid iron. Hot reduction gases are blasted through a burden consisting of iron ore pellets, slag, flux, and coke. The chemical reactions that occur through the furnace reduce the iron ore pellets into liquid iron as they descend through the furnace. Experimental studies and live operation measurements can be extremely difficult to perform on a blast furnace due to the extremely harsh environment generated by the operational process. Computational Fluid Dynamics (CFD) modeling has been developed and applied to simulate the complex multiphase reacting flow inside a blast furnace shaft. The model is able to predict the burden distribution pattern, Cohesive Zone (CZ) shape, gas reduction utilization, coke rate, and other operational conditions. This paper details the application of this model to investigate the effects of coke size and porosity, iron ore pellet size, and burden descent speed on blast furnace efficiency.

CFD Simulation of a 6-Cylinder Diesel Engine Intake and Exhaust Manifold

Exhaust gas recirculation (EGR) is a nitrogen oxide (NOx) emissions reduction technique used in petrol/gasoline and diesel engines. By recirculating a portion of an engine’s exhaust, inert gas displaces combustible matter in the cylinder. Because NOx forms primarily when a mixture of nitrogen and oxygen is subjected to high temperature, the lower combustion chamber temperatures caused by EGR decrease the amount of NOx combustion generates. This project aims at optimizing the location of the EGR ports, which are crucial to the operation and efficiency of the EGR system. The Computational Fluid Dynamics (CFD) code ANSYS FLUENT was used to analyze the intake and exhaust manifold working processes. In order to conduct numerical optimization on determining the best EGR port location, a transient CFD model was developed. Real operational transient boundary conditions were applied to the model through user defined functions (UDF), and the results of flow characteristics and EGR distribution was analyzed in detail. The EGR mass flow rate mal-distribution was presented at the transient simulation. This model can be utilized for further optimization purposes.Copyright

Numerical Simulation for the Splashing Behavior in an Oxygen Converter Process

The three-dimensional model has been developed to analyze the transient mixing process of a vertical static oxygen converter with top and bottom oxygen lances blowing oxygen into the liquid steel and slag. Multiphase Volume of Fluid (VOF) method was employed to model three phases including oxygen, liquid steel, and liquid slag to simulate the behaviors of splashing. Numerical simulation was conducted to clarify the transient phenomena of oxygen injection into the vessel and the formation of splashing. The modeling simulations show that the splashing is quite violent when the bottom lances inject oxygen with high flow rate. Some liquid steel and slag were splashed onto the higher lining and tap hole, even out of the vessel which cause kidney formation and buildup. When bottom lances inject oxygen with low flow rate, the splashing is much better. The research results revealed the kidney formation and buildup, and the optimized flow rate was obtained.

Optimization of an Urea Decomposition Chamber Using CFD and VR

Selective Catalytic Reduction (SCR) is an important air pollution control process that consists of injecting ammonia (NH3) into the boiler flue gas and passing the flue gas through a catalyst bed where the NOx and NH3 react to form nitrogen gas (N2) and water vapor (H2O). [1] At a coal-fired power station, a decomposition chamber uses combustion air and a natural gas burner to provide the necessary temperature, air flow and pressure to convert the injected urea solution into ammonia gas. The inspections of this decomposition chamber indicate debris formations occurring at the burner/roof block the chamber from achieving proper temperature for conversion and redirect the burner flame/flow, which can potentially shift the flow pattern in the chamber. In order to identify the cause of this debris formation, Computational Fluid Dynamics (CFD) and Virtual reality fVR have been employed to simulate and visualize the flow distribution and species concentration inside this decomposition chamber. By analyzing the simulation data, excessive ammonia recirculation had been identified as the cause of the debris formation at the top of the chamber. Parametric studies have also been conducted to optimize the existing chamber design by introducing multiple turning vanes to eliminate the excessive recirculation, thus minimizing debris formation.Copyright

Numerical Simulation of an Industrial Fluid Catalytic Cracking Riser

A three-dimensional multi-phase, multi-species, turbulent reacting flow computational fluid dynamics (CFD) model was established to simulate fluid catalytic cracking (FCC) process inside an industrial FCC riser. FCC catalyst, oil, and air were used as the solid, liquid, and gas phases, respectively. A hybrid technique for coupling chemical kinetics and hydrodynamics computations was employed, where the simulation was divided into (a) reacting flow hydrodynamic simulation with a small but sufficient number of lumped reactions to compute flow filed properties and (b) and reacting flow hydrodynamics with many subspecies where complex chemical reactions occur. A four-lump kinetic model was used for the major species and a fourteen-lump kinetic model was used for the subspecies model. The results were validated against measurements from the actual riser.Copyright

Development of a Comprehensive Virtual Training Package for Power Plant Boiler

As one of the most important components in coal-fired power station, the operators and maintenance crews of boiler systems receive comprehensive training in unit operation procedures and emergency preparedness. Due to the inaccessibility of the field environment, the majority of the training sessions take place in a classroom using 2D presentation materials such as pictures, drawings, etc. In order to provide a more efficient training program, a software package for power plant boilers was developed through the integration of Computational Fluid Dynamics (CFD) and Virtual Reality (VR) visualization. Using numerical simulation data, the package creates a computer-generated boiler in which the users can observe the actual phenomenon in an easily-understood context. It also allows instructors and trainees to selectively explore various components, operating conditions and scenarios using the built-in Graphic User Interface (GUI). This training package enables people who are unfamiliar with boiler operations to gain better understanding in much less time.Copyright