Advanced One-Dimensional Entrained-Flow Gasifier Model Considering Melting Phenomenon of Ash

A one-dimensional model is developed to represent the ash-melting phenomenon, which was not considered in the previous one-dimensional (1-D) entrained-flow gasifier model. We include sensible heat of slag and the fusion heat of ash in the heat balance equation. To consider the melting of ash, we propose an algorithm that calculates the energy balance for three scenarios based on temperature. We also use the composition and the thermal properties of anorthite mineral to express ash. gPROMS for differential equations is used to solve this algorithm in a simulation; the results include coal conversion, gas composition, and temperature profile. Based on the Texaco pilot plant gasifier, we validate our model. Our results show good agreement with previous experimental data. We conclude that the sensible heat of slag and the fusion heat of ash must be included in the entrained flow gasifier model

Techno-economic and environmental impact analysis of tuyere injection of hot reducing gas from low-rank coal gasification in blast furnace

Our goal is to find a strategy to reduce coke use during operation of a blast furnace (BF). This study focuses on the techno-economic and environmental impact analysis of tuyere injection of hot reducing gas (HRG) from low-rank coal (LRC) gasification in the BF. LRC gasification by entrained-flow gasifier is introduced to make gaseous fuel, and the cleaning process of the raw syngas is implemented using Aspen Plus V10. The effects of HRG injection are evaluated using a BF model derived from the Rist operating diagram. Integrated results from raw fuel to the BF were analyzed considering economic, energy, and environmental aspects. By injecting rich syngas (>95 vol %) into the BF at 1150 K, coke replacement ratio is estimated to be 0.354 kg/Nm3 without adverse impact on the BF. The most sensitive economic factor is coke price. The energy efficiency of raw syngas cleaning process, relative energy intensity of LRC, gas utilization ratio are 57.5%, 90.6%, and 50.0% respectively. Utilization of HRG can reduce CO2 emission by 21.88 ktCO2/yr compared to the reference BF operation.11Nsciescopu

Techno-economic and environmental impact analysis of tuyere injection of hot reducing gas from low-rank coal gasification in blast furnace

Our goal is to find a strategy to reduce coke use during operation of a blast furnace (BF). This study focuses on the techno-economic and environmental impact analysis of tuyere injection of hot reducing gas (HRG) from low-rank coal (LRC) gasification in the BF. LRC gasification by entrained-flow gasifier is introduced to make gaseous fuel, and the cleaning process of the raw syngas is implemented using Aspen Plus V10. The effects of HRG injection are evaluated using a BF model derived from the Rist operating diagram. Integrated results from raw fuel to the BF were analyzed considering economic, energy, and environmental aspects. By injecting rich syngas (>95 vol %) into the BF at 1150 K, coke replacement ratio is estimated to be 0.354 kg/Nm(3) without adverse impact on the BF. The most sensitive economic factor is coke price. The energy efficiency of raw syngas cleaning process, relative energy intensity of LRC, gas utilization ratio are 57.5%, 90.6%, and 50.0% respectively. Utilization of HRG can reduce CO2 emission by 21.88 kt(CO2)/yr compared to the reference BF operation. (C) 2021 Published by Elsevier Ltd

Recent advances in optical imaging through deep tissue: imaging probes and techniques

Abstract Optical imaging has been essential for scientific observations to date, however its biomedical applications has been restricted due to its poor penetration through tissues. In living tissue, signal attenuation and limited imaging depth caused by the wave distortion occur because of scattering and absorption of light by various molecules including hemoglobin, pigments, and water. To overcome this, methodologies have been proposed in the various fields, which can be mainly categorized into two stategies: developing new imaging probes and optical techniques. For example, imaging probes with long wavelength like NIR-II region are advantageous in tissue penetration. Bioluminescence and chemiluminescence can generate light without excitation, minimizing background signals. Afterglow imaging also has high a signal-to-background ratio because excitation light is off during imaging. Methodologies of adaptive optics (AO) and studies of complex media have been established and have produced various techniques such as direct wavefront sensing to rapidly measure and correct the wave distortion and indirect wavefront sensing involving modal and zonal methods to correct complex aberrations. Matrix-based approaches have been used to correct the high-order optical modes by numerical post-processing without any hardware feedback. These newly developed imaging probes and optical techniques enable successful optical imaging through deep tissue. In this review, we discuss recent advances for multi-scale optical imaging within deep tissue, which can provide reseachers multi-disciplinary understanding and broad perspectives in diverse fields including biophotonics for the purpose of translational medicine and convergence science. Graphical Abstract Methodologies for multi-scale optical imaging within deep tissues are discussed in diverse fields including biophotonics for the purpose of translational medicine and convergence science. Recent imaging probes have tried deep tissue imaging by NIR-II imaging, bioluminescence, chemiluminescence, and afterglow imaging. Optical techniques including direct/indirect and coherence-gated wavefront sensing also can increase imaging depth

Ultrastable-Stealth Large Gold Nanoparticles with DNA Directed Biological Functionality

The stability of gold nanoparticles (AuNPs) in biological samples is very important for their biomedical applications. Although various molecules such as polystyrenesulfonate (PSS), phosphine, DNA, and polyethylene glycol (PEG) have been used to stabilize AuNPs, it is still very difficult to stabilize large AuNPs. As a result, biomedical applications of large (30–100 nm) AuNPs are limited, even though they possess more favorable optical properties and are easier to be taken up by cells than smaller AuNPs. To overcome this limitation, we herein report a novel method of preparing large (30–100 nm) AuNPs with a high colloidal stability and facile chemical or biological functionality, via surface passivation with an amphiphilic polymer polyvinylpyrrolidone (PVP). This PVP passivation results in an extraordinary colloidal stability for 13, 30, 50, 70, and 100 nm AuNPs to be stabilized in PBS for at least 3 months. More importantly, the PVP capped AuNPs (AuNP-PVP) were also resistant to protein adsorption in the presence of serum containing media and exhibit a negligible cytotoxicity. The AuNP-PVPs functionalized with a DNA aptamer AS1411 remain biologically active, resulting in significant increase in the uptake of the AuNPs (∼12 200 AuNPs per cell) in comparison with AuNPs capped by a control DNA of the same length. The novel method developed in this study to stabilize large AuNPs with high colloidal stability and biological activity will allow much wider applications of these large AuNPs for biomedical applications, such as cellular imaging, molecular diagnosis, and targeted therapy