Maximizing Demineralization during Chemical Leaching of Coal through Optimal Reagent Addition Policy

2015 ◽  
Vol 10 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Pratik S. Dash ◽  
D. N. Prasad ◽  
Santosh K. Sriramoju ◽  
R. K. Lingam ◽  
A. Suresh ◽  
...  
Keyword(s):  
Coal Ash ◽  
Hierarchical Optimization ◽  
Mineral Matter ◽  
Batch Reactors ◽  
Simulation Studies ◽  
Time Intervals ◽  
Chemical Leaching ◽  
Minimal Quantity ◽  
Leaching Experiments ◽  
Optimum Sequence

Abstract The main objective of the optimal reagent addition was to maximize the quantity of product with minimal quantity of feed. In the present study, the optimal addition of reagents during the chemical leaching of coal was computed. Chemical leaching of coal was carried out using aqueous solution of caustic to dissolve and remove the mineral matter. Simulation studies were carried out using the optimal reagent addition for chemical leaching of coal in batch reactors. This was experimentally validated, using the bench-scale reactor setup with hierarchical optimization architecture. Chemical leaching experiments were conducted using West Bokaro coal. Samples collected at various time intervals during the experiment were analyzed. Variations in silica (SiO2) and alumina (Al2O3) concentrations, which were main constituents present in coal ash, were evaluated with respect to time for different concentrations of caustic. The simulation studies for optimal addition were carried out at 6, 8 and 10 intervals. An objective function, required for maximum ash removal, was solved, using sequential quadratic programming (SQP) algorithm to find out the optimum sequence for reagent dosing. An improvement of about 1% (wt) ash reduction on an average was observed with implementation of optimal reagent addition.

Abstract 147: Rapid Responder Operating Times for Out-of-hospital Cardiac Arrest Using Three Automated External Defibrillator Models

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_4) ◽  
Author(s):  
Mengqi Gao ◽  
Chenguang Liu ◽  
Dawn Jorgenson
Keyword(s):  
Cardiac Arrest ◽  
Life Support ◽  
Operating Time ◽  
Sudden Cardiac Arrest ◽  
The United States ◽  
Automated External Defibrillator ◽  
Simulation Studies ◽  
Time Intervals ◽  
Shock Delivery ◽  
External Defibrillator

Background: Early defibrillation with an automated external defibrillator (AED) is crucial for improving the survival rate in out-of-hospital resuscitation from sudden cardiac arrest (SCA). Chance of survival decreases by 7% to 10% for every minute that defibrillation is delayed. While simulation studies have been used to assess AED usability factors, our objective was to report the actual operating time for three Philips AED models used in SCA responses. Methods: A convenience dataset recorded by Philips AEDs (HS1, FRx, or FR3) was obtained from Europe and the United States from 2007 - 2018. The HS1 is intended for minimally trained or untrained individuals, the FRx is for Basic Life Support (BLS), and the FR3 is for both BLS and Advanced Life Support (ALS) responders. A retrospective analysis was conducted to report the operating time intervals for cases where a shock was delivered after initial rhythm analysis. The study analyzed 90 HS1, 46 FRx and 32 FR3 cases. Results: Compared with HS1, both FRx (p < 0.001) and FR3 (p = 0.001) responders spent less time in placing pads on the patient after powering on the AED (Figure 1) as expected. Similarly, time intervals from the start of shock advised prompt to first shock delivery for FRx (p = 0.02) and FR3 (p < 0.01) are shorter than for HS1. Time from AED power-on to first shock was within 90 seconds in 74.4% (67 of 90) HS1 cases, 97.8% (45 of 46) FRx cases, and 100% (32 of 32) FR3 cases. On average, the FR3 and FRx responders were able to deliver the first shock within 48 seconds. Conclusions: The analysis shows that responders were able to quickly apply the AEDs and respond to the shock advisory prompt for all three AED models despite different training levels. This real-world performance is better than most reported simulation studies, however, this analysis cannot convey variety of activities that account for the differences in timing (e.g. pads applied before power-on, or compressions began before applying pads, etc.).

scholarly journals Evaluation of Pig Manure for Environmental or Agricultural Applications through Gasification and Soil Leaching Experiments

2021 ◽  
Vol 11 (24) ◽  
pp. 12011
Author(s):  
Despina Vamvuka ◽  
Adamantia Raftogianni
Keyword(s):  
Carbon Dioxide ◽  
Soil Amendment ◽  
Activated Carbons ◽  
Raw Materials ◽  
Structural Characteristics ◽  
Pig Manure ◽  
Mineral Matter ◽  
Soil Leaching ◽  
Agricultural Applications ◽  
Leaching Experiments

The current study aimed at evaluating an untreated pig manure, firstly for its suitability for soil amendment in combination with an agricultural/bio-solid biochar, and secondly for its potential to be used for adsorption of hazardous species, replacing expensive activated carbons. Column soil leaching experiments were designed to simulate field conditions, and physical, chemical and mineralogical analyses were performed for raw materials and/or leachates. For activated carbon production, the manure was gasified by steam or carbon dioxide at high temperatures. Biochars were analyzed for organic and mineral matter, structural characteristics and organic functional groups. Activation by steam or carbon dioxide greatly enhanced specific surface area, reaching values of 231.4 and 233.3 m2/g, respectively. Application of manure to the soil promoted leaching of nitrates and phosphates and raised COD values of water extracts. Biochar addition retained these ions and reduced COD values up to 10 times at the end of the three-month period. The concentrations of heavy metals in the leachates were low and, in the presence of biochar in soil blends, they were significantly reduced by 50–70%. The manure presents a significant potential for adsorption of various pollutants or improvement of soil amendment if carefully managed.

An Improved Model of Sulfur Self-Retention by Coal Ash During Coal Combustion in FBC

2005 ◽  
Author(s):  
Vasilije Manovic ◽  
Borislav Grubor
Keyword(s):  
Thermal Decomposition ◽  
Fluidized Bed ◽  
Coal Ash ◽  
Sulfur Oxides ◽  
Mineral Matter ◽  
Fluidized Bed Combustion ◽  
Particle Volume ◽  
Reaction Rate Constants ◽  
Dependent Relation ◽  
Improved Model

During combustion of coal a significant amount of sulfur may be retained in ash due to the reactions between mineral matter in coal and sulfur oxides. This process is known as sulfur self-retention and its significance lies in the fact that a part of sulfur oxides, one of the main pollutants during combustion of coal, is not released in the atmosphere. Sulfur self-retention is influenced by parameters that depend on coal characteristics and combustion conditions. The interest for this process was enhanced with the introduction of fluidized bed combustion (FBC) technology since the temperatures and other conditions are favorable for sulfur self-retention. Investigation of this process, primarily modeling, is the subject of this work. The presented model is based on the previously developed model for the combustion of porous char particles under FBC conditions, along with a changing grain size model of sulfation of the CaO grains dispersed throughout the char particle volume. Incorporating the phenomena of sintering, reduction of the produced CaSO4 with CO, thermal decomposition of the produced CaSO4, as well as allowing for the different reactivity of various forms of calcium make major improvements of the model. A temperature dependent relation for the CaO grain radius takes sintering into account. Reductive and thermal decomposition were taken into account by the corresponding reaction rate constants of the Arrhenius type. The reactivity of the calcium forms in coal was considered by different initial radius of the CaO grains. The model was verified by the experimental results of sulfur self-retention of three Serbian coals during combustion in a fluidized bed combustion reactor. The comparison with the experimentally obtained results showed that the model can adequately predict the levels of the obtained values of sulfur self-retention efficiencies, as well as the influence of temperature, coal type and coal particle size.

Chemical Leaching on Sulfur and Mineral Matter Removal from Asphaltite (Harbul, SE Anatolia, Turkey)

2011 ◽  
Vol 33 (5) ◽  
pp. 383-391 ◽  
Author(s):  
A. Saydut ◽  
M. Z. Duz ◽  
S. Erdogan ◽  
Y. Tonbul ◽  
C. Hamamci
Keyword(s):  
Mineral Matter ◽  
Chemical Leaching

Mineral Matter Transformation of Coal Ash under Gasification Atmosphere: A Case of Huolinhe Lignite

2011 ◽  
Vol 347-353 ◽  
pp. 3732-3735 ◽  
Author(s):  
Feng Hai Li ◽  
Jie Jie Huang ◽  
Yi Tian Fang ◽  
Yang Wang
Keyword(s):  
Low Temperature ◽  
Alkali Metal ◽  
Fluidized Bed ◽  
Coal Ash ◽  
Volume Ratio ◽  
Phase Changes ◽  
Mineral Matter ◽  
Alkali Metal Oxide ◽  
Reducing Atmosphere ◽  
Initial Melting

Experiments have been conducted with Huolinhe lignite low temperature ashes (HLH-LTA) to investigate the mineral behaviors under gasification atmosphere (H2/CO2=1:1, volume ratio) with the temperature increase by SEM and XRD. The results show that the contents of SO3 and alkali metal oxide (e.g. K2O, Na2O) are higher in the HLH-LTA than that in laboratory HLH ashes. The formation of some low-melting ferrous eutectic compounds causes the initial melting temperature of HLH-LTA is lower about 300 °C than its deformation temperature. The formation of slag during HLH fluidized-bed gasification is the results of the interaction among minerals and phase changes with the temperature increases under reducing atmosphere.

Parameter Estimation of Kinetic Model Equations for Chemical Leaching of Coal

2014 ◽  
Vol 9 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Santosh Kumar Sriramoju ◽  
A. Suresh ◽  
Pratik Swarup Dash ◽  
P. K. Banerjee
Keyword(s):  
Rate Equation ◽  
Kinetic Equations ◽  
Parametric Estimation ◽  
Core Model ◽  
Mineral Matter ◽  
Shrinking Core Model ◽  
Chemical Leaching ◽  
Leaching Process ◽  
Heterogeneous Rock ◽  
Shrinking Core

Abstract Coals are invariably associated with mineral matter, which makes it unsuitable for efficient utilisation. For difficult-to-wash coals, advanced coal beneficiation technologies like chemical leaching methods are under development. In this paper, kinetic equations using different methods have been evolved, and related parameters have been estimated, using the experimental results obtained during coal leaching process. As coal is a heterogeneous rock, three different methods namely (i) parametric estimation through rate equation, (ii) non-linear regression and (iii) parametric estimation through shrinking core model have been developed and validated to check the minimum level of permitted error tolerance. Experiments were designed, using full factorial design with three variables, which are sensitive to the process. Values of activation energy and k0 obtained, using the parametric estimation of rate equation and shrinking core model, are almost in the same range. The order of the reaction for silica and alumina is two, using rate equation method. The parametric data obtained from the polynomial regression method were compared with the actual data. The exponential polynomial provides a better fit for the chemical leaching process of coal.

Recycling of Florescent Phosphor Powder Y2O3:Eu by Leaching Experiments

2017 ◽  
Vol 262 ◽  
pp. 596-600
Author(s):  
Romy Auerbach ◽  
Katrin Bokelmann ◽  
Stefan Ratering ◽  
Rudolf Stauber ◽  
Sylvia Schnell ◽  
...  
Keyword(s):  
New Technologies ◽  
Raw Materials ◽  
Waste Products ◽  
Chemical Leaching ◽  
Process Waste ◽  
Biosorption Process ◽  
The Future ◽  
Abiotic Control ◽  
Leaching Experiments ◽  
Fe Addition

Due to the advancing development of new technologies and consumer goods the future demand for raw materials will rise significantly. The finite primary raw materials will not be able to meet the demand quickly enough or the prices for the extraction will rise enormously. In consequence, a recycling of process waste and end of life products will be in future an essential step in order to meet the demand. Y2O3:Eu fluorescent phosphor was identified as the main composition in phosphor waste fractions and was chemical leached and bioleached with A. ferrooxidans. A selective leaching towards Y in bioleaching batches was observed and already after four days 100 % could be leached. The bioleaching with the bacteria showed no significant differences in comparison to the abiotic control without microorganism. Initial Fe3+ in the medium was identified as the driving force and lower extraction efficiencies of the biotic batches were attributed to a biosorption process and to high pH-values. This work showed that the extraction of yttrium out of waste products with high Y2O3:Eu content by chemical leaching with Fe-addition under mild conditions offers a good perspective to support the material demand of Y in the future growing market. In comparison to bioleaching of other fluorescent phosphors and waste fractions leaching efficiencies up to 100% were achieved and it was identified that the microorganisms can positively influence the leaching effect. Furthermore, it became obvious that the leaching behavior of microorganisms was highly dependent on the sample material. As relevant parameters mainly the structural composition of the phosphor was identified.

Slag-Coal Interface Phenomena

1966 ◽  
Vol 88 (1) ◽  
pp. 40-44 ◽  
Author(s):  
E. Raask
Keyword(s):  
Carbon Monoxide ◽  
Molten Slag ◽  
Iron Carbide ◽  
Coal Ash ◽  
Sulfur Oxides ◽  
Mineral Matter ◽  
Slag Removal ◽  
Interface Phenomena ◽  
Coal Particles ◽  
Initial Melting

In a cyclone system of combustion or gasification with molten-slag removal a large proportion of the coal is thrown to the slag-coated cyclone walls before it has time to burn. The welting properties of coal-ash slag on devolatilized coal, the evolution of gases from molten slag when in contact with coal particles, and the effect of mineral matter on combustion of coal have been investigated briefly using a heating microscope. Coal-ash slag does not wet coal or coal residues, thus combustion of the coal particles on the surface of molten slag is not retarded. Evolution of gases lakes place from the slag (a) on its initial melting with release of sulfur oxides, and above 1400 C where carbon monoxide is given off when the slag is in contact with coal. The latter is explained in terms of the formation of iron carbide at the slug/carbon interface, the carbide then diffuses into the slag where it reads with silica.

The Effect of Ca-Rich Deposits on the High Temperature Degradation of Coated and Uncoated Superalloys

2008 ◽  
Vol 595-598 ◽  
pp. 805-812 ◽  
Author(s):  
Kee Young Jung ◽  
Frederick S. Pettit ◽  
Gerald H. Meier
Keyword(s):  
Gas Turbines ◽  
Cyclic Oxidation ◽  
Alternative Fuels ◽  
Coal Ash ◽  
Mineral Matter ◽  
Type I ◽  
Platinum Aluminide ◽  
Alternate Fuels ◽  
Different Characteristics ◽  
Type Ii Hot Corrosion

When gas turbines use alternate fuels, such as syngas derived from coal, ash from the fuels can deposit on turbine hardware. These deposits can cause substantial corrosion of the hardware which may have significantly different characteristics than Type I and Type II hot corrosion. The composition of the ash is determined by the mineral matter in coals, which often have kaolinite (Al2O3·2SiO2·2H2O), pyrites (FeS2), and calcites (CaCO3) as major components. This study was directed at degradation produced by CaO and CaSO4 and comparing it with the attack induced by Na2SO4 deposits. The alloys GTD 111, IN 738, and René N5, as well as these alloys coated with CoNiCrAlY and platinum aluminide, were exposed to conditions relevant to corrosion induced using alternative fuels. The initial test conditions involved a number of deposits including Na2SO4, CaO, and CaSO4 in dry and wet (pH2O = 10.1 kPa, 0.1 atm) air at 950oC. The most severe degradation occurred with CaO deposits. Specimens of the three alloys were subsequently exposed to cyclic oxidation conditions at 950oC with deposits of CaO in dry and wet air. All three alloys were attacked more severely when CaO deposits were present and this attack became even more severe in wet compared to dry air. However, the increase in attack caused by the presence of water vapor was small compared to the attack caused by the CaO deposits. The degradation induced via CaO deposits caused more severe degradation of René N5 compared to GTD 111 and IN 738. Tests using CaO deposits and cyclic oxidation conditions at 950oC in dry and wet air were also performed for the two coatings on the three alloy substrates. Both coatings were significantly degraded by attack induced by the CaO deposits. No effect of the alloy substrates on coating performance was apparent. Mechanisms for the effects of Ca-rich deposits on superalloy and coating degradation are discussed.

scholarly journals Morphology and chemical composition of mineral matter present in fly ashes of bituminous coal and lignite

2020 ◽  
Author(s):  
E. Strzałkowska
Keyword(s):  
Chemical Composition ◽  
Bituminous Coal ◽  
Coal Ash ◽  
Heterogeneous Material ◽  
Raw Material ◽  
Spherical Particles ◽  
Hard Coal ◽  
Mineral Matter ◽  
Fly Ashes ◽  
Main Component

AbstractThe changing properties of energy waste force us to look for alternative directions of their use. The aim of the research presented in this paper was to indicate the possibilities of managing fly ashes from bituminous coal and lignite based on the observation of individual particles of these ashes. Innovative research techniques were used, among others: SEM with EDS detector and Image Analysis. Microscopic observations have shown that fly ashes are a heterogeneous material composed of particles occurring in three basic morphological forms: spherical, irregular and fine-detritic. A high proportion of spherical particles was found in bituminous coal ashes (rich in SiO2 and Al2O3), which gives them high pozzolanic activity. This kind of morphology and chemical composition make these ashes a potential material for zeolites synthesis. The amorphic phase of ash from lignite coal has aluminium–silicate-calcium chemical composition, which is what determines pozzolanic and hydraulic properties of these ashes. Magnetic separation of iron-rich particles may be a way to manage the researched ashes. One of the valuable components of hard coal ash are microspheres, which are characterized by high variability in chemical composition, so further utilization will require prior refining. The main component of irregular particles found in ashes is unburned coal and, to a lesser extent, a mineral substance. The separation of all useful components from the tested ashes before their further management will allow the full use of their raw material potential.

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