Performance and Reaction Mechanism of a Novel Coking Binder Obtained from Low-Grade Coal.

Under the premise of ensuring the quality of coke, reducing coking/fat coal utilization is an urgent problem in the coking industry. This study prepared an extract with softening and bonding characteristics from noncaking low-grade coal by a degradative solvent extraction method. The substitution effect of coking/fat coal by the extract for coking was studied, and the effect mechanism was analyzed in detail.

Decoupling the influence of NO in flue gas on the application of nano-amorphous selenium for mercury removal.

Nitrogen oxides are inevitable hazardous components in coal-fired flue gas. This study designed a series of experiments and combined theoretical calculations to systematically investigate the effect of NO on the removal of element mercury (Hg) by nano-amorphous selenium (nano-a-Se). It was found that the impact of NO on the removal of Hg by nano-a-Se primarily involves two mechanisms: competitive adsorption between NO and Hg, and the induced reduction effect of NO on chemisorbed mercury (HgSe).

Enhancement of fine particle removal through flue gas cooling in a spray tower with packing materials.

The efficient removal of fine particles from coal-fired flue gas poses challenges for conventional electrostatic precipitators and bag filters. Recently, a novel approach incorporating deep cooling of the flue gas has been proposed to enhance the removal of gaseous pollutants and particles. However, the achievable efficiency and underlying mechanisms of particle capture within the gas cooling system remain poorly understood.

Insight into volatile-char interaction mechanisms of biomass torrefaction based on three major components.

Volatile-char interaction is an important phenomenon in biomass thermal conversion process, which significantly contributes to the decomposition, deoxygenation and upgrading of biomass. However, the deep insight into volatile-char interaction mechanisms between hemicellulose, cellulose and lignin is currently unclear. In this work, above mechanism was studied through systematic single-/bi-component torrefactions and the follow-up char analysis.

Simulation and experimental study of gas-phase diffusion coefficient of selenium dioxide.

Improving the removal effect of selenium in wet flue gas desulfurization system is a key way to reduce the emission of selenium pollutants from coal-fired power plants. In order to clarify the removal mechanism of selenium pollutants in the desulfurization tower, it is necessary to obtain accurate selenium gas-phase diffusion coefficient. In this paper, molecular dynamics simulations were used to carry out theoretical calculations of gas-phase diffusion coefficients of SeO (the main form of selenium in coal combustion flue gas).

Comprehensive effect of increased calcium content in coal on the selenium emission from coal-fired power plants: Combined laboratory and field experiments.

Coal combustion is the major contributor to global toxic selenium (Se) emissions. Inorganic elements in coals significantly affect Se partitioning during combustion. This work confirmed that the calcium (Ca) in ash had a stronger relationship with Se retention at 1300 °C than other major elements.

Improving Fine Particle Removal Using a Single-Channel Slit Bubbling Device in Wet Flue Gas Desulfurization System.

To improve the cleanliness of coal-fired power plants' particulate matter emissions, a novel device (single-channel slit bubbling particle removal device (SCSB-PRD)) is proposed to improve the wet flue gas desulfurization system's (WFGDs) collaborative particle removal effect. Actual coal-fired flue gas was used to test the particle removal performance. The results showed that the flue gas temperature had no obvious effect on the scrubbing effect of the SCSB-PRD.

Modeling of arsenic migration and emission characteristics in coal-fired power plants.

After coal combustion, the minerals present in fly ash can adsorb arsenic (As) during flue gas cooling and reduce As emissions. However, a quantitative description of this adsorption behavior is lacking. Herein, the As adsorption characteristics of minerals (Al/Ca/Fe/K/Mg/Na/Si) were investigated, and a model was developed to predict As content in fly ash.

Gas-Pressurized Torrefaction of Lignocellulosic Solid Wastes: Deoxygenation and Aromatization Mechanisms of Cellulose.

A novel gas-pressurized (GP) torrefaction method at 250 °C has recently been developed that realizes the deep decomposition of cellulose in lignocellulosic solid wastes (LSW) to as high as 90% through deoxygenation and aromatization reactions. However, the deoxygenation and aromatization mechanisms are currently unclear. In this work, these mechanisms were studied through a developed molecular structure calculation method and the GP torrefaction of pure cellulose.

Partitioning of selenium from coal to fly ash: The key roles of Fe-bearing minerals and implications for Se potential recovery.

The roles of Ca/Fe phases on selenium (Se) enrichment behavior in fly ash during coal combustion were investigated by examining the Ca/Fe mineralogy of various ash samples, exploring the binding forms of Se in fly ashes, and performing bench-scale adsorption experiments (150-1000 ℃). The results indicated that Se capture by fly ash is a function of flue gas temperature, particle size, and more importantly, the contents and form of Ca/Fe in combustion ash. Physical condensation/adsorption was mainly determined by temperature and particle size, contributing to less than 25% of total Se in fly ash.

Gas-pressurized torrefaction of lignocellulosic solid wastes: Low-temperature deoxygenation and chemical structure evolution mechanisms.

A novel gas-pressurized (GP) torrefaction realizes deeper deoxygenation of lignocellulosic solid wastes (LSW) to as high as 79% compared to traditional torrefaction (AP) with the oxygen removal of 40% at the same temperature. However, the deoxygenation and chemical structure evolution mechanisms of LSW during GP torrefaction are currently unclear. In this work, the reaction process and mechanism of GP torrefaction were studied through follow-up analysis of the three-phase products.

Flue Gas-Enhanced Water Leaching: AAEM Removal from Agricultural Organic Solid Waste and Fouling and Slagging Suppression during Its Combustion.

Alkali and alkaline earth metals (AAEMs) in agricultural organic solid waste (AOSW) contribute to the fouling and slagging during its combustion. In this study, a novel flue gas-enhanced water leaching (FG-WL) method using flue gas as the heat and CO source was proposed for effective AAEM removal from AOSW before combustion. The removal rate of AAEMs by FG-WL was significantly superior to that by conventional water leaching (WL) under the same pretreatment conditions.

Effect of Al modification on the adsorption of AsO on the CaSiO(001) surface: A DFT study.

CaSiO is highly resistant to sintering and can trap arsenic at high temperatures in the boiler furnace. However, the trapping capacity of CaSiO for arsenic does not meet the requirements of practical applications, and it is easy to react with acidic gases, which significantly affects the adsorptive property of arsenic. In this paper, the effect of Al modification on the AsO adsorption behaviour on the CaSiO(001) surface was systematically investigated using a density functional theory.

A critical review on lead migration, transformation and emission control in Chinese coal-fired power plants.

Coal is widely utilized as an important energy source, but coal-fired power plant was considered to be an important anthropogenic lead emission source. In the present study, the distribution characteristics of lead in coal and combustion by-products are reviewed. Specifically, lead is mainly transferred to ash particles and the formation and migration mechanisms of particulate lead are summarized.

Fine particulate-bound arsenic and selenium from coal-fired power plants: Formation, removal and bioaccessibility.

The arsenic (As) and selenium (Se) in fine particulate matter (PM) have attracted increasing attentions due to their health effects. However, the emission control of fine particulate-bound arsenic and selenium (fine particulate-bound As/Se) from coal-fired power plants still faces various challenges. Understanding the formation and characteristics of fine particulate-bound As/Se is crucial for developing specific control technologies.

Yield prediction of "Thermal-dissolution based carbon enrichment" treatment on biomass wastes through coupled model of artificial neural network and AdaBoost.

The "Thermal-dissolution based carbon enrichment" was proven as an efficient and homogenizing treatment method in converting biomass wastes into similar high-quality carbon materials. However, their yields varied significantly with respect to the different experimental parameters employed. It is therefore imperative to establish the correlation between product yield and experimental parameters for material selection and condition optimization.

Condensation and adsorption characteristics of gaseous selenium on coal-fired fly ash at low temperatures.

Gaseous selenium is of high saturated vapor pressure, making its retention in solid phases quite difficult during coal combustion. The selenium transformation from gaseous form into solid phases at low temperatures can be essential to control selenium emission. To understand the migration of SeO (g) on ash particles in the low-temperature zone, this study investigated the speciation of selenium in fly ash and simulated the physical retention of SeO (g) on fly ash.

Kinetic Study on Continuous Sampling of Coal Char from a Micro Fluidized Bed.

We self-design a micro fluidized bed reactor (MFB) with combination of an online char particle sampling system to study the kinetics of coal char combustion and gasification. The system mainly contains two parts: a micro fluidized bed and vacuum online sampling. Vientiane coal was continuously sampled from the MFB.

Do FeCl and FeCl/CaO conditioners change pyrolysis and incineration performances, emissions, and elemental fates of textile dyeing sludge?

The pyrolysis and incineration performances of sulfur-rich textile dyeing sludge (TDSS) were determined in response to the additions of FeCl or FeCl + CaO. The emissions of eight air pollutants from the incineration and pyrolysis were systematically identified. The 3-to-8% FeCl additions increased the comprehensive combustibility index by 2.

Potential hazards of novel waste-derived sorbents for efficient removal of mercury from coal combustion flue gas.

Novel waste-derived sorbents synthesized through one-step co-pyrolysis of wood and PVC (or brominated flame retarded plastic) were demonstrated as cost-effective sorbents for mercury (Hg) removal in our previous studies. To introduce magnetism and improve porosity, Fe species were further doped into such waste-derived sorbents. The ultimate fate of Hg-laden sorbents after their service is mainly disposed in landfill.

Fate of chromium with the presence of HCl and steam during oxy-coal combustion: Quantum chemistry and experimental study.

Quantum chemistry combined with kinetic simulation and drop tube furnace (DTF) experiments were conducted to reveal the transformation behavior of chromium at the presence of steam and HCl under oxy-coal combustion. A completed kinetic system Cr‒O‒H‒Cl containing 107 elementary reactions was firstly proposed. The unknown microcosmic reaction paths and corresponding Arrhenius parameters were calculated via quantum chemistry.

Gas-pressurized torrefaction of biomass wastes: Co-gasification of gas-pressurized torrefied biomass with coal.

Co-gasification of coal and biomass offers a relatively cleaner utilization way of fossil fuel. The fuel property improvement of biomass can not only improve the property of syngas but also enhance the synergistic effect during the co-gasification. In our previous work, a novel gas-pressurized (abbreviated as GP) torrefaction was proposed to effectively upgrade the biomass under mild condition.

Mercury stable isotope fractionation during gaseous elemental mercury adsorption onto coal fly ash particles: Experimental and field observations.

Mercury (Hg) stable isotopes have a great potential to track coal combustion Hg emissions, but mass-dependent fractionation (MDF) during Hg adsorption onto fly ash particles could significantly alter isotope signatures of emitted Hg species. The detailed processes causing this MDF, however, are not well understood. Here, we simulated how isotopes fractionate during gaseous Hg adsorption onto fly ash at different times and temperatures.

Gas-pressurized torrefaction of biomass wastes: The optimization of pressurization condition and the pyrolysis of torrefied biomass.

A novel gas-pressurized (GP) torrefaction with high oxygen removal efficiency at mild temperature was proposed in our previous work. However, the optimal condition of the GP torrefaction and subsequent pyrolysis of the torrefied biomass were not clear. In this work, the effect of pressure on the GP torrefaction and pyrolysis product properties of the torrefied biomass were studied in detail.

Modeling Study of Selenium Migration Behavior in Wet Flue Gas Desulfurization Spray Towers.

Wet flue gas desulfurization (WFGD) system is the core equipment for removing SO from coal-fired power plants, and it also has an important synergistic effect on the removal of selenium. However, the removal efficiency of Se across WFGD systems is not as expected, and it varies greatly in different coal-fired units (12.5-96%).