Investigation of the Effects of Coke Reactivity and Iron Ore Reducibility on the Gas Utilization Efficiency of Blast Furnace

The use of coke with high reactivity in the ironmaking blast furnace (BF) has yet to be explored, and a thorough understanding is still required to clarify the effect of coke reactivity on the BF gas utilization efficiency. In this paper, a one-dimensional kinetic model of the BF is presented and the accuracy of the model is verified. The model is then applied to analyze the effect of coke reactivity on the gas utilization efficiency of the BF. The results show that, under the operating conditions considered, the height of indirect reduction region and the starting temperature of coke solution loss reaction decrease with the increase of coke reactivity. Moreover, coke reactivity is first, directly proportional to gas utilization efficiency, and then, inversely proportional to it. In addition, high-reactivity coke may not improve gas utilization efficiency in case of high H2 content. Both, lowly and highly reactive coke need to be combined with highly reducible iron ore to maximize the gas utilization efficiency. Nevertheless, only appropriately reactive coke can combine with lowly reducible iron ore to obtain an optimal gas utilization efficiency. Hence, it is necessary to select coke with appropriate reactivity, in accordance with iron-ore reducibility, instead of blindly pursuing high-reactivity coke in actual operation

Two-photon-pumped amplified spontaneous emission and cavity lasing of an organic dye HEASPS in PHEMA polymer

Two-photon-absorption (TPA)-induced upconverted amplified spontaneous emission (ASE) and cavity lasing of a styrylpyridinium dye: trans-4-[p-(N-hydroxyethyl-N-ethylamino)styryl]-N-methylpyridinium p-toluene sulfonate (abbreviated as HEASPS) in poly(2-hydroxyethyl methacrylate) (abbreviated as PHEMA) polymer were observed under a picosecond pump condition. The spectral and temporal behaviors of TPA-induced fluorescence, ASE and cavity lasing were studied. The cavity lasing with a total oscillation time of more than 200 ps was achieved when pumped with 1064-nm, 50-ps laser irradiation. The population inversion could persist for three times longer than the duration of the pump pulse. The gain coefficients of the dye-doped polymer at various wavelengths were calculated based on cavity lasing spectra and one-photon fluorescence spectra

Model Study on Burden Distribution in COREX Melter Gasifier

COREX is one of the commercialized smelting reduction ironmaking processes. It mainly includes two reactors, i.e., a (reduction) shaft furnace (SF) and a melter gasifier (MG). In comparison with the conventional blast furnace (BF), the COREX MG is not only equipped with a more complicated top charging system consisting of one gimbal distributor for coal and eight flap distributors for direct reduction iron (DRI), but also the growth mechanism of its burden pile is in a developing phase, rather than that in a fully-developed phase in a BF. Since the distribution of charged burden plays a crucial role in determining the gas flow and thus in achieving a stable operation, it is of considerable importance to investigate the burden distribution influenced by the charging system of COREX MG. In the present work, a mathematical model is developed for predicting the burden distribution in terms of burden layer structure and radial ore/coal ratio within the COREX MG. Based on the burden pile width measured in the previous physical experiments at different ring radii on a horizontal flat surface, a new growth mechanism of burden pile is proposed. The validity of the model is demonstrated by comparing the simulated burden layer structure with the corresponding results obtained by physical experiments. Furthermore, the usefulness of the mathematical model is illustrated by performing a set of simulation cases under various charging matrixes. It is hoped that the model can be used as a what-if tool in practice for the COREX operator to gain a better understanding of burden distribution in the COREX MG

Two-photon fluorescence properties of a styrylpyridinium derivative organic chromophore in different solvents

The fluorescence properties of a new two-photon absorption chromophore in dimethyl formamide, methanol, acetone, benzyl alcohol, methylene chloride and chloroform are reported. The lifetime, intensity and central wavelength of the fluorescence signal vary significantly in different solvents. The fluorescence properties are explained by using the twisted intra-molecular charge-transfer model, the viscosity of the solvents and the formation of the hydrogen bond. For the dye in all solvents, the longer the fluorescence lifetime, the higher the fluorescence intensity. Generally, the higher the dipole moments, the longer the central wavelengths of the dye

Upconversion fluorescence and optical power limiting effects based on the two- and three-photon absorption process of a new organic dye BPAS

Abstract not available

Estimation of the Blast Furnace Hearth State Using an Inverse-Problem-Based Wear Model

An undisturbed and well-controlled hearth state is an essential prerequisite for achieving a long campaign life and low production costs in an ironmaking blast furnace, because hearth wear and hot metal and slag drainage are crucial factors in its operation. With the objective to estimate the hearth state of the refractory of a three-taphole blast furnace, a wear model of the hearth erosion and skull formation was developed. The model is based on thermocouple readings in the hearth lining and solves an inverse heat conduction problem for a series of co-axial vertical slices, where the erosion and skull lines are optimized simultaneously. The model is optimized for fast computation by adopting a novel procedure featuring fixed mesh during the looping calculation. The results revealed that the hearth refractory showed an elephant-foot-shaped profile with excessive erosion in the hearth periphery, indicating that liquid flows are suppressed in the hearth bottom and that the permeability of the core of the deadman is low. These findings were further elaborated and confirmed by a comparison between the estimated hearth state and other key operation variables, including the coke rate, blast kinetic energy, and residual carbon appetite of the hot metal

An Experimental Technique for Investigating the Skulling Behavior in the Blast Furnace Hearth

The skulling behavior in the blast furnace (BF) hearth has yet to be investigated as few (if any) industrial/experimental studies with particular focus on hot metal are reported in the open literature. As a necessary first step toward a better understanding of the sophisticated behavior, an experimental technique is introduced in the present paper. The experimental apparatus, which mainly consists of a vertical tube furnace, a rotating and moveable pedestal, and a moveable water-cooled probe covered with a multi-layer structured refractory sleeve can utilize industrial coke, pig iron, and BF hearth carbon brick as raw materials. The technique is shown to be capable of producing chemical, thermal, and mechanical conditions similar to those in the real process. The feasibility and potential of the technique are demonstrated by a set of experimental runs. The results indicate that the air gap between the cooling device and the refractory lining plays a decisive role in both skull formation and lining erosion. Furthermore, the microstructure of graphite precipitated during solidification is influenced by the cooling rate, which in practice is affected by the BF hearth operating parameters. It is hoped that the current contribution will stimulate the growing research interest in this subject.Peer reviewe

Superradiance and lasing properties of new two-photon absorption dye DEASPS

Pumped by picosecond pulses from a Nd:YAG laser, a new lasing dye, trans-4-[4′-(N,N-diethylamino)styryl]-N-methyl pyridinium methyl sulfate (abbreviated to DEASPS), shows both intense superradiance and strong lasing properties in benzyl alcohol solution. By using streak camera systems, the superradiance and lasing can be distinguished both spectrally and temporally. It has been found that the peak wavelength of lasing is at 620 nm with a red-shift of about 12 nm to the superradiance wavelength. The lasing pulse shows an oscillatory effect that it is not found in the superradiance pulse. The fluorescence lifetime is 529±40 ps and the effective molecular two-photon absorption is (1.25 ± 0.1) × 10-48 cm4·s·photon-1, measured using a nonlinear transmittance method. This dye shows effective optical limiting of the pumping wavelength

Two-photon absorption and nonlinear optical properties of a new organic dye PSPI

Abstract not available

Two-photon-absorption and upconverted superradiance properties of organic dye HEASPS-doped linear homogeneous polymer at several wavelengths

The spectral and temporal properties of single- and two-photon fluorescence of a dye-doped linear homogeneous polymer are reported. The dopant is a new organic dye, trans-4-p-(N-hydroxyethyl-N-ethylamino)styryl-N-methylpyridinium p-toluene sulfonate (HEASPS), synthesized by researchers at the State Key Laboratory, Jinan China. When the dye is excited by near-infrared laser radiation, strong upcoverted fluorescence and superradiance can be observed. The difference in the blueshift of two-photon superradiance compared with that of two-photon fluorescence is explained by the use of different reabsorption coefficients under different conditions. The lifetime of two-photon fluorescence in a solid was measured to be 4.14 ns, which was much longer than that in solution. Two-photon transmittance and upconversion efficiencies at different wavelengths were measured with an optical parameter amplifier as the pump source. The strongest two-photon absorption occurred at 930 nm. The highest upconversion efficiency was 4.05% at 1030 nm. A possible mechanism is discussed