Research on Reasonable Particle Size of Coal Blends for Blast Furnace Injection: Semi Coke and Bituminous Coal

2015 ◽  
pp. 613-619
Author(s):  
Haiyang Wang ◽  
Runsheng Xu ◽  
Tengfei Song ◽  
Pengcheng Zhang
Keyword(s):  
Particle Size ◽  
Blast Furnace ◽  
Bituminous Coal

Obtaining and investigation of a finely dispersed fraction of granulated blast-furnace slags for use as components of clinker-free binders

2021 ◽  
pp. 56-63
Author(s):  
B. B. Khaidarov ◽  
D. S. Suvorov ◽  
D. V. Lysov ◽  
A. K. Abramov ◽  
G. G. Luchnikova ◽  
...  
Keyword(s):  
Particle Size ◽  
Blast Furnace ◽  
Physicochemical Characteristics ◽  
Air Classification ◽  
Granulated Slag ◽  
Comprehensive Study

A method for obtaining a finely dispersed fraction of ground blast-furnace granulated slag has been developed. The resulting material with the introduction of an alkaline additive can be offered as an alternative to foreign analogous fine-dispersed mineral binders, an example of which can be microcement. A comprehensive study of granular slags of two metallurgical plants was carried out, the physicochemical characteristics of materials were determined. The possibility of obtaining a fraction of ground granular slag with a particle size of no more than 16 microns using vortex electromagnetic homogenization and subsequent air classification is shown.

Effects of Briquettes with Different Crack Structures on Propagation Characteristics of Ultrasonic Waves under Wetting Conditions

2020 ◽  
Author(s):  
Gang Wang ◽  
Jinzhou Li ◽  
Huaixing Li ◽  
Zhiyuan Liu ◽  
Yanpei Guo ◽  
...  
Keyword(s):  
Particle Size ◽  
Ultrasonic Velocity ◽  
Bituminous Coal ◽  
Ultrasonic Attenuation ◽  
Crack Size ◽  
Ultrasonic Waves ◽  
Ultrasonic Frequency ◽  
Propagation Characteristics ◽  
Sample Mass ◽  
Velocity Increase

Abstract In order to examine the effect of briquettes with different crack structures on ultrasonic characteristics under different wetting conditions, a series of ultrasonic testing are carried out on briquettes at different wetting heights and the ultrasonic characteristics in these coal samples are explored. The results show that ultrasonic amplitude is positively correlated with the emission voltage, whereas ultrasonic frequency is negatively correlated with the emission voltage. Changes in both are closely related to the particle size and density. The ultrasonic velocity is positively correlated with the wetting degree. Sample mass has the greatest effect on the ultrasonic velocity, followed by particle size, and pressure has the smallest effect. At dry stage, ultrasonic velocity in gas coal is less than that in bituminous coal. The opposite is true in the fully wet state. The influence of crack thickness on ultrasonic velocity gradually increases with the wetting degree increasing. At dry stage, the velocity gradually increases with the crack dip increasing, while as the wetting height increasing, magnitude of velocity increase gradually decreases with the dip increasing. The ultrasonic attenuation in the briquettes reduces with the emission voltage enhancing. The attenuation decreases with sample particle size, crack thickness and crack size decreasing and with sample mass, pressure and crack dip increasing. The ultrasonic attenuation shows a trend of increase before decrease with the wetting height increasing. The attenuation of ultrasonic wave increases with wave velocity increasing for intact samples and shows a trend of increase before decrease for cracked samples.

Computational Study of 16 kWth Furnace Cofired Using Pulverized Bituminous Coal and Liquified Petroleum Gas Operated in Un-Staged and Air-Staged Conditions

2020 ◽  
Vol 143 (8) ◽  
Author(s):  
Nitesh Kumar Sahu ◽  
Mayank Kumar ◽  
Anupam Dewan
Keyword(s):  
Particle Size ◽  
Coal Particle ◽  
Bituminous Coal ◽  
Computational Study ◽  
Pearson Correlation ◽  
Turbulence Models ◽  
The Other ◽  
Test Facility ◽  
Measured Temperature ◽  
Inlet Swirl

Abstract This paper presents a computational study on air-fuel combustion of bituminous coal and liquified petroleum gas (LPG) in a 16 kWth test facility with a coflow-swirl burner. The performance of three turbulence models is investigated for the furnace operated under both air-staged and un-staged conditions by comparing their predictions with the reported measurements of temperature and species concentrations. This comparison shows that the shear stress transport (SST) k–ω model and SST k–ω model with low-Re correction predict the profiles of temperature and species concentrations reasonably well, but significantly underpredict the temperature in the furnace core at axial locations away from the burner. On the other hand, the transition SST k–ω model provides better overall congruency with the measured temperature and species concentrations when compared with the other turbulence models used, as indicated by relatively higher values of the Pearson correlation coefficient at locations away from the burner. The present high-fidelity computational model developed is also capable of accurately simulating the effect of coal particle size on the furnace environment, which is verified by the match between the computational predictions and the experimental results for two different sized coal samples. The model is also used to investigate the effect of coal particle size on the internal recirculation zone (IRZ) and the reattachment length (LR) for the same inlet swirl number (SN). A decrease of nearly 50% in the coal sample size results in the increase of LR and IRZ length by 20% and 82.6%, respectively.

Fuel Flexible Biomass Reburn Technology

2009 ◽  
Author(s):  
Guang Xu ◽  
Wei Zhou ◽  
Larry Swanson
Keyword(s):  
Particle Size ◽  
Bituminous Coal ◽  
Nox Reduction ◽  
Unburned Carbon ◽  
Gas Temperature ◽  
Mean Particle Size ◽  
High Volatility ◽  
Order Of Magnitude ◽  
Char Reactivity ◽  
Computational Fluid Dynamics Cfd

Biomass reburn is a low NOx alternative to cofiring that effectively uses the high volatility and high char reactivity of biomass for NOx reduction. In this paper, computational fluid dynamics (CFD) and thermal modeling, and a NOx prediction model were used to evaluate the impacts of sawdust/coal reburn on the performance of a 250 MW opposed-fired boiler burning bituminous coal as the primary fuel. The results showed that the reburn system maintained overall boiler performance with a 50 – 70 °F reduction in the furnace exit gas temperature. Predicted losses in thermal efficiency were caused by the lower biomass fuel heating value (similar to biomass cofiring) and increase in unburned carbon. The higher unburned carbon emissions were attributed to an order of magnitude larger biomass mean particle size relative to bituminous coal. Thus, LOI emissions can be improved significantly by reducing the biomass mean particle size. The NOx predictions showed that for reburn rates above about 19%, adding dry sawdust biomass to a coal reburn system can improve NOx reduction; i.e., using pure dry sawdust as reburn fuel at 30% of the total heat input can lead to NOx levels about 30% less than those for pure coal reburn under for similar firing conditions.

Prediction of Raceways in a Blast Furnace

2006 ◽  
Author(s):  
Naresh K. Selvarasu ◽  
D. Huang ◽  
Zumao Chen ◽  
Mingyan Gu ◽  
Yongfu Zhao ◽  
...  
Keyword(s):  
Particle Size ◽  
Blast Furnace ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Gas Oil ◽  
Cfd Model ◽  
Coke Particle ◽  
Fuel Gas ◽  
Computational Fluid Dynamics Cfd ◽  
Insight Into

In a blast furnace, preheated air and fuel (gas, oil or pulverized coal) are often injected into the lower part of the furnace through tuyeres, forming a raceway in which the injected fuel and some of the coke descending from the top of the furnace are combusted and gasified. The shape and size of the raceway greatly affect the combustion of, the coke and the injected fuel in the blast furnace. In this paper, a three-dimensional (3-D) computational fluid dynamics (CFD) model is developed to investigate the raceway evolution. The furnace geometry and operating conditions are based on the Mittal Steel IH7 blast furnace. The effects of Tuyere-velocity, coke particle size and burden properties are computed. It is found that the raceway depth increases with an increase in the tuyere velocity and a decrease in the coke particle size in the active coke zone. The CFD results are validated using experimental correlations and actual observations. The computational results provide useful insight into the raceway formation and the factors that influence its size and shape.

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