Free Swelling Index Research Articles

A new Ensemble based multi-agent system for prediction problems: Case study of modeling coal free swelling index

In this article, a new ensemble based multi-agent system called “EMAS” is introduced for prediction of problems in data mining. The EMAS is constructed using a four-layer multi-agent system architecture to generate a data mining process based on the coordination of intelligent agents. The EMAS performance is based on data preprocessing and prediction. The first layer is dedicated to clean and normalize data. The second layer is designed for data preprocessing by using intelligent variable ranking to select the most effective agents (select the most important input variables to model an output variable). In the third layer, a negative correlation learning (NCL) algorithm is used to train a neural network ensemble (NNE). Fourth layer is dedicated to do three different subtasks including; knowledge discovery, prediction and data presentation. The ability of the EMAS is evaluated by using a robust coal database (3238 records) for prediction of Free Swelling Index (FSI) as an important problem in coke making industry, and comparing the outcomes with the results of other conventional modeling methods Coal particles have complex structures and EMAS can explore complicated relationships between their structural parameters and select the most important ones for FSI modeling. The results show that the EMAS outperforms all presented modeling methods; therefore, it can be considered as a suitable tool for prediction of problems. Moreover, the results indicated that the EMAS can be further employed as a reliable tool to select important variables, predict complicated problems, model, control, and optimize fuel consumption in iron making plants and other energy facilities.

A multi-attribute decision making approach of mix design based on experimental soil characterization

The clay mineral composition is one of the major factors that governs the physical properties of silty sand subgrade. Therefore, a thorough knowledge of mineral composition is essential to predict the optimum engineering properties of the soil, which is generally characterized by different indices like maximum dry density (MDD), California bearing ratio (CBR), unconfined compressive strength (UCS) and free swelling index (FSI). In this article, a novel multiattribute decision making (MADM) based approach of mix design has been proposed for silty sand–artificial clay mix to improve the characteristic strength of a soil subgrade. Experimental investigation has been carried out in this study to illustrate the proposed approach of selecting appropriate proportion for the soil mix to optimize all the above mentioned engineering properties simultaneously. The results show that a mix proportion containing approximately 90% silty sand plus 10% bentonite soil is the optimal combination in context to the present study. The proposed methodology for optimal decision making to choose appropriate combination of bentonite and silty sand is general in nature and therefore, it can be extended to other problems of selecting mineral compositions.

Producing low-ash coal by microwave and ultrasonication pretreatment followed by solvent extraction of coal

Low ash clean coal was produced from Indian coking coal through microwave irradiation or ultrasonication followed by solvent extraction in N-methyl-2-pyrollidone (NMP) containing smaller amount of Ethylenediamine (EDA) or Monoethanolamine (MEA). Pretreatment by ultrasonication followed by extraction with only NMP gave 10–15% higher clean coal yield of (56–58%) than extraction with only NMP (without pretreatment). Effect of using up to 10% EDA as cosolvent in NMP led to maximum clean coal yield. However use of EDA concentration beyond this showed decrease in clean coal yield and increase in ash contents. Clean coal yield increases because EDA is a strong polar solvent and strong base, which disrupts coal interactions and breaks bonds in coal by acid-base interactions. The extraction yield with and without pretreatment and microwave irradiation led to the enhancement in the yield of clean coal and was found to be in the range of 66–70% with microwave irradiation, which was 3–4% higher than without pretreatment. Clean coal Free Swelling Index (FSI) was improved by one unit. This was demonstrated at lab scale. Subsequently, this process was scaled up to 40 kg/batch coal mini-pilot plant.

Properties of Kuznets Basin gas coal

Six samples of G coal characterized by different vitrinite reflection coefficient (R o,r = 0.64–0.74%) are investigated. With increase in R o,r , the plastic-layer thickness y increases from 7 to 17 mm, the free-swelling index SI from 0.5 to 3.5, and the Roga index RI from 1 to 21. The temperature range of plasticity expands from 34 to 94°C. The results clarify the difference in clinkering properties of the gas coal.

Improving the properties of high volatile coking coals by controlled mild oxidation

Four bituminous coals of the same rank but with different thermoplastic properties were oxidized at 40 and 50°C for one month. The chemical changes due to oxidation were studied by applying Gieseler plastometry, the free-swelling index (FSI), thermogravimetric analysis and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). In general, oxidation at 50°C produced a greater impairment of coking properties, the different responses to oxidation depending on the parent coal. The main effects caused by oxidation were a loss of thermoplastic properties, a decrease in aliphatic hydrogen and a slight increase in groups with oxygen functionalities.Both the fresh and oxidized coals were carbonized in a movable-wall oven of 17kg capacity and the quality of the resulting cokes was tested by means of the JIS and ASTM standard methods. The results showed that, in certain cases, mild oxidation produced an improvement in coke quality. Oxidation also affected the porosity of the cokes, which may be related to the coke quality. It was found that the higher quality cokes had less macroporosity, whereas the lower quality cokes had a higher pore volume.

Study the Effect of Weathering on Coal and Coke Quality

ABSTRACTIn this study weathering was carried out for coals (source wise) in open piles at the Bhilai Steel Plant (BSP). Imported hard coals were selected for these studies. Several methods such as alkali extraction test, measurement of the free-swelling index, and the pH of the coal slurry have been applied to monitor coal weathering. These tests suggest that the pH of the coal slurry and alkali extractions are better methods to identify the weathered coals. The relative sensitivity to weathering for hard coals was also determined. These coals were carbonized using a box filled with coal at a bulk density of 830 kg/m3 in a commercial oven at the Bhilai Steel Plant. In each case, the coke produced from weathered coal deteriorates the coke quality, but the degree was different for different coals.

Effect of Rate of Crude Oil Contamination on Index Properties and Engineering Properties of Clays and Sands

Background: The recent advancements and industrial growth has adversely affected the environment which has direct or indirect impact on geotechnical properties of soil. One of the most perturbed sources of contamination is crude oil contamination, which basically takes place either due to accidental spillage of crude oil or through the industrial waste. This leads to alternation of index properties, chemical properties as well as engineering properties of soil. Methodology: Many researchers have worked on studying the impact of crude oil contamination on various types of soil. Present research work, focuses on not only evaluating the extent of alternation of the index properties (Specific Gravity, Liquid Limit, Plastic Limit, Shrinkage Limit) as well as engineering properties (Free Swelling Index) for Kaolinite Clay and fine grained sand due to crude oil contamination but also the effect of rate of crude oil contamination viz. 3%, 6% and 9% of crude oil contamination on both the soil types by performing geotechnical tests in accordance with IS Code:2720 part 3-1 (1980), part 5,6 (1985), part 40 (1977) respectively on non-contaminated soil samples as well as crude oil contaminated soil samples. For this purpose, the crude oil contaminated samples were prepared in the laboratory at water content equal to the liquid limit; simulating the in-situ conditions. Findings and Conclusion: The results thus obtained find its application in comparing the effect of crude oil on fine grained and coarse grained soil. The coarse grained soil (sand) due to its inherent structure and high permeability allows the penetration of crude oil at higher rate than that of fine grained soil (clay) which have low permeability and thus are less liable to get affected due to crude oil contamination. Increment in rate of crude oil contamination can be stated for the deterioration of geotechnical properties for both the soil types.

Modeling of free swelling index based on variable importance measurements of parent coal properties by random forest method

Abstract Coke quality has a critical role in the steelmaking industry. The aim of this study is to examine the complex relationships between various conventional coal analyses using coke making index “free swelling index (FSI)”. Random forest (RF) associated with variable importance measurements (VIMs), which is a new powerful statistical data mining approach, is utilized in this study to analyze a high-dimensional database (3961 samples) to rank variables, and to develop an accurate FSI predictive model based on the most important variables. VIMs was performed on various types of analyses which indicated that volatile matter, carbon, moisture (coal rank parameters) and organic sulfur are the most effective coal properties for the prediction of FSI. These variables have been used as an input set of RF model for the FSI modeling and prediction. Results of FSI model indicated that RF can provide a satisfactory prediction of FSI with the correlation of determination R 2 = 0.96 and mean square error of 0.16 from laboratory FSIs (which is smaller than the interval unit of FSI; 0.5). Based on this result, RF can be used to rank and select effective variables by evaluating nonlinear relationships among parameters. Moreover, it can be further employed as a non-parametric reliable predictive method for modeling, controlling, and optimizing complex variables; which to our knowledge has never been utilized in the fuel and energy sectors.

Explaining relationships between coke quality index and coal properties by Random Forest method

In this study was shown that random forest (RF) can be used as a sensible new data mining tool for variable importance measurements (VIMs) through various coal properties for prediction of coke quality (Free Swelling Index (FSI)). The VIMs of RF within coal analyses (proximate, ultimate, and petrographic analyses) were applied for the selection of the best predictors of FSI over a wide range of Kentucky coal samples. VIMs assisted by Pearson correlation through proximate, ultimate, and petrographic analyses indicated that volatile matter, carbon, vitrinite, and Rmax (coal rank parameters) are the most effective variables for the prediction of FSI. These important predictors have been used as inputs of RF model for the FSI prediction. Outputs in the testing stage of the model indicated that RF can predict FSI quite satisfactorily; the R2 was 0.93 and mean square error from actual FSIs was 0.15 (had less than interval unit of FSI; 0.5). According to the result, by providing nonlinear inter-dependence approximation among parameters for variable selection and also non-parametric predictive model RF can potentially be further employed as a reliable and accurate technique for the determination of complex relationship through fuel and energy investigations.

The Effects of High Alkaline Fly Ash on Strength Behaviour of a Cohesive Soil

Contemporarily, there are 16 coal-burning thermal power plants currently operating in Turkey. This number is expected to rise to 46 in the future. Annually, about 15 million tons of fly ash are removed from the existing thermal power plants in Turkey, but a small proportion of it, 2%, is recyclable. Turkey’s plants are fired by lignite, producing Class C fly ash containing a high percentage of lime. Sulfate and alkali levels are also higher in Class C fly ashes. Therefore, fly ash is, commonly, unsuitable as an additive in cement or concrete in Turkey. In this study, highly alkaline fly ash obtained from the Yeniköy thermal power plants is combined with soil samples in different proportions (5%, 10%, 15%, 20%, and 25%) and changes in the geomechanical properties of Ankara clay were investigated. The effect of curing time on the physicomechanical properties of the fly ash mixed soil samples was also analyzed. The soil classification of Ankara clay changed from CH to MH due to fly ash additives. Free swelling index values showed a decrease of 92.6%. Direct shear tests on the cohesion value of Ankara clay have shown increases by multiples of 15.85 and 3.01 in internal friction angle values. The California bearing ratio has seen a more drastic increase in value (68.7 times for 25% fly ash mix).

Improvement of the Strength of Ankara Clay with Self-cementing High Alkaline Fly Ash

Turkey's plants are fired by lignite, producing class C fly ash containing a high percentage of lime. Sulphate and alkali levels are also higher in class C fly ashes. Therefore, fly ash is, commonly, unsuitable as an additive in cement or concrete in Turkey. In this study, highly alkaline fly ash obtained from the Yenikoy thermal power plants is combined with soil samples in different proportions (5%, 15%, and 25%) and changes in the geomechanical properties of Ankara clay were investigated. The effect of curing time on the physical-mechanical properties of the fly ash mixed soil samples was also analyzed. Free swelling index values showed a decrease of 92.6%. The California bearing ratio has seen a more drastic increase in value (68.7 times for 25% fly ash mix).

Organo-refining of high-ash Indian coals at bench scale

Organo-refining is a process of solvent extraction through which organic matters are extracted from coal using organic solvents. Indian coals have high mineral matter content ranging from 25 to 45wt.% (dry basis). The ash in coal is highly disseminated, which makes it difficult to remove by physical beneficiation. Thus, chemical beneficiation is needed to remove the mineral matter. This study was conducted for high ash Indian coals at bench scale. The capacity of the bench scale plant was 40kg/batch feed basis. Coking coal, washery discards and thermal coals of bituminous origin were used as feed material. The mineral matter of these coals varied in the range of 27–36wt.% (db). The feed size of the particle was below −0.5mm. N-methyl-2-pyrrolidone (NMP) and ethylenediamine (EDA) were used as main solvent and co-solvent respectively. The extraction was done at 200°C with 1:6 coal to solvent ratio (by mass, wt./wt.) for 60min. Extraction was followed by solid–liquid separation, solvent recovery and washing of products. The feed and product materials were subjected to proximate analysis, ultimate analysis, and Free Swelling Index (FSI) tests. Organo-refining process produced clean coal yield in the range of 30–45% and clean coal mineral matter was less than 10% for coking as well as non-coking coals. Free Swelling Index (FSI) also improved from 1–5 range for feed coals to 7–8 for product clean coals. Two types of filter (basket and centrifuge) were also tried for separation of solid and liquid from different types of slurries. It was observed that cake moisture can be reduced by 6–12% points for these slurries using decanter centrifuge. The cake moisture reduced to 70% from 76% for clean coal slurry and 60% to 48% for reject slurry. The clean coal yield increased by 5 units (from 35% to 40%) with decanter centrifuge filter. In order to have better filtration and precipitation, the extraction was carried out by mixing of two different raw coals (TL and TC) in a certain ratio (1:1 to 1:3). Also, the extraction was done separately for TL and TC coals and then the clean coal extracts were mixed in 1:1 to 1:3 proportions. Mixing of two raw coals gives better results (36wt.% yield with 6.4% ash clean coal) than mixing of their extracts (30wt.% yield with 6.7% ash clean coal).

Analyzing the effect of various soil properties on the estimation of soil specific surface area by different methods

Depending on the method used, measuring the specific surface area (SSA) can be expensive and time consuming and limited numbers of studies have been conducted to predict SSA from soil properties. In this study, 127 soil sample data were gathered from the available literature. The data set included SSA values and some of the soil physical and chemical index properties. At the first step, linear regression, non-linear regression, regression trees, artificial neural networks, and a multi-objective group method of data handling were used to develop seven pedotransfer functions (PTFs) for the purpose of finding the best method in predicting SSA. Results showed that the artificial neural networks performed better than the other methods used in the development and validation of PTFs. At the second step, to find the best set of SSA for predicting input variables and to investigate the importance of the input parameters, the artificial neural networks were further used and 25 models were developed. The results showed that the PTF, containing the input variables of sand%, clay%, plastic limit, liquid limit, and free swelling index performed better than the other PTFs. This can be attributed to the close relation between the free swelling index and Atterberg limits with the soil clay mineralogy, which is one of the most important factors controlling SSA. The sensitivity analysis showed that the greatest sensitivity coefficients were found for the cation exchange capacity, clay content, liquid limit, and plasticity index in different models. Overall, the artificial neural networks method was proper to predict SSA from soil variables.

Reduction of Caking Propensity in Large (Millimeter-Sized) South African Coal Particles with Potassium Carbonate Impregnation To Expand Fixed- and Fluidized-Bed Gasification Feedstock Suitability

The caking propensity of coal causes challenges in combustion, gasification, and fluidized-bed applications, where this property limits coal selection. Certain gasifiers are fitted with mitigation technologies such as stirrers to overcome operational problems associated with caking. However, additive addition is a possible alternative method with benefits such as reduction of caking and swelling and increased reaction rates. It is known that select additives alter the coal’s thermoplastic behavior, where studies have predominantly focused on powdered coal. Here, large coal particles (5, 10, and 20 mm) suitable for select fluidized-bed and gasification applications, from three South African coal fields, were examined. The coals have different thermal swelling characteristics: Highveld (TWD) (FSI 0), Grootegeluk (GG) (FSI 5.5–6.5), and Tshikondeni (TSH) (FSI 9) (where FSI is the free swelling index). Digital photography, SEM, and X-ray computed tomography were used to evaluate the caking propensity during d...

Application of the Taguchi Method in Establishing Criticality of Parameters that Influence Cracking Characteristics of Fine-Grained Soils

Extensive studies have been conducted by earlier researchers to understand cracking characteristics of fine-grained soils. Based on these studies, several theories and models which facilitate understanding the effect of various soil- and environment-specific parameters (viz., clay content, plasticity, free swelling index, specimen dimensions, boundary conditions, temperature, and humidity) that influence cracking characteristics of such soils have been proposed. A critical synthesis of the existing literature reveals that selection of any crack sealing/arresting technique would largely depend on the most critical of these parameters. However, studies related to identification of this critical parameter(s) and its (their) influence on cracking characteristics of fine-grained soils are not available in the existing literature. Hence, efforts have been made in the present study to establish the effect of each of these parameters on the cracking characteristics of fine-grained soils and the most critical parameter(s) has/have been identified. To achieve this, the Taguchi method, which is basically a statistical method and has been widely adopted for designing experiments and optimizing and/or detecting the most influential parameter(s) from the set of parameters of any multi-variant problem, has been employed. From the present study, it has been demonstrated that temperature, humidity, and mineralogy are the most critical parameters that affect cracking behavior of fine-grained soils.

Petrographic and Chemical Characterization of the Bonito Seam and its Beneficiation Products, South Santa Catarina Coalfield — Brazil

The Bonito seam has become recently a new exploration and exploitation target in the South Santa Catarina Coalfield, Brazil. The present study is a contribution to an understanding of the petrographical and chemical characteristics of the Bonito seam collected at three underground mine sites, followed by beneficiation tests using a density range from <1.6 to > 2.4 g/cm3. Seam Characteristics and Ash Fusibility Tests. Averaged ash yield is 58 wt.%, volatile matter content is 16 wt.%, and calorific value is 2910 cal/g. Vitrinite reflectance indicate high volatile B bituminous rank. Inertinite and vitrinite maceral groups are most abundant. Quartz, kaolinite and pyrite are the predominant minerals. The Free Swelling Index is 1. Ash Fusibility Tests indicated an initial deformation temperature at 1260 °C, and a flow temperature at 1473 °C. Beneficiation tests. In the beneficiated sample a gradual increase of ash yields with increasing density fraction occurs, whereas volatile matter, calorific values and fixed carbon decrease. Technological properties. High ash yields and low FSI values in the 1.6 and <1.6 g/cm3 density fractions, and the predominance of non-reactive components prevents the use of the Bonito seam in coke-making. The beneficiated samples showed, however, a high potential to be used in combustion.

Activation of Jordanian Ore Bentonite by Sodium Carbonates

The Hashemite Kingdom of Jordan has a large reserve of raw Bentonite in the area of Ain Al-Baida at Basin of Al-Azraq city that has not activated yet to become valid as drilling mud. The Ore Ain AL-Baida Bentonite was investigated and activated by Na2CO3. The products were investigated by chemical analysis, X-Ray Diffraction, rheological properties and free swelling index with clay fraction. It was observed that the activities clay ranged between 0.98 < AC < 1.48 medium to high content of clay minerals. In addition, it was determined the Atterberg limits, the results of plasticity chart and relation between index and clay fraction. This means that the amount of the attracted water will be suitable influenced by the clay that is present in Ore Ain Al-Baida bentonite. The liquid limit was ranged between 83% to 140%, and plastic limit ranged between 39% - 48%. Also, rheological properties (apparent viscosity, plastic viscosity), gel strength, yield point, filtrate loss. These properties have been compared with those standard specifications properties required for the drilling fluid in order to know the appropriate circumstances to activate the Bentonite ore of Ain Al Baida at Azraq basin to become close to the standard specifications required for the drilling fluids, the ratio between Y.P/P.V was ranged 0.88 to 1.21, it is meant that the behavior of drilling fluids confirms the Bingham plastic and power-law rheological models using fine grinding of bentonite mixture with 3% - 6% concentration of sodium carbonate powder.

Hydrogen and Syngas Generation from Gasification of Coal in an Integrated Fuel Processor

Hydrogen is a clean and new energy carrier to generate power and effectively turned out through the gasification of organic material such as coal. The main objective of this manuscript is to present an analysis of the coal gasification for the generation of high-purity hydrogen in a lab-scale fixed-bed downdraft gasifier. Better understanding of the rank, formation, structure, composition and calorific value and method of analysis of the material is crucial for the proper utilization of these resources requires. Traditionally the quality of the Coal samples has been determined by their physical and proximate analysis, such as, bulk density, free swelling index, gross calorific value, sulfur, moisture, fixed carbon, volatile matter and ash content. In this study, coal is partially oxidized and ultimately converts into hydrogen rich syngas (CO and H2). As well, approximately 220 kg h−1 of coal would be gasified at 673–1073 K and 46.2 atm with the reactor volume 0.27m3 to obtain approximately 3.8×105 kcal h−1 of thermal energy during over 67% syngas generation with the generation of 110kW electrical powers.

EFFECT OF FLY ASH ON GEOTECHNICAL PROPERTIES OF LOCAL SOIL-FLY ASH MIXED SAMPLES

The primary fuel of thermal power plants i.e. coal generates significantly huge quantities of solid byproduct as fly ash, bottom ash and pond ash (called fly ash in this study). Fly ash have been collected from Kolaghat Thermal Power Plant, Kolaghat, West Bengal, India. Concerning the major challenges regarding the safe reuse, management and disposal of these wastes an attempt has been made to mix fly ash at 10, 15, 20, 25, and 30% on the basis of dry weight with local silty-clay soil (Sand= 10.65%, Silt= 52.35% and Clay = 37.00%). The local silty-clay soil collected from river bank near to NIT, Agartala, Tripura, India. The study is carried out through large scale tests to simulate field conditions as closely as possible and found to be a very effective means to control the specific gravity (G), liquid limit (LL) and plastic limit (PL), linear shrinkage (L-S), initial void ratio (ei), initial degree of saturation (Si), maximum dry density (MDD) and optimum moisture content (OMC) at standard Proctor compaction energy, hydraulic conductivity (k), unconfined compressive strength (UCS), free swelling index (FSI), and swelling potential (SP) characteristics. With increase of fly ash contents in the soil-fly ash mixed samples specific gravity, linear shrinkage, plasticity, MDD, Si, UCS, FSI, and SP have been decreased and OMC, ei increased. Depending on above percentages of fly ash in mixed samples hydraulic conductivity values achieved for soil, soil mixed with 10% of fly ash (Kolaghat fly ash), and soil mixed with 30% of fly ash (Kolaghat bottom ash) are 8.60 10 -9 cm/s, 3.50 10 -8 cm/s, and 1.53 10 -7 cm/s respectively. Up to 30% of fly ash contents in soil-fly ash mixed sample, this material can be used as liner. 30% of fly ash contents or above in soil-fly ash mixed sample, this material may be used as land filling and embankments in the field of geotechnical engineering construction.

Determination of Weathering of Coal Using pH Values of the Coal Slurry

During transportation and stockpiling, coal is in contact with air for periods of time that may exceed 6 months. During this time, reaction with oxygen in the presence of water, sunlight, and possibly elevated temperatures may take place. The resulting weathered coal suffers some alteration in its physical and chemical properties. This article describes weathering with reference to coking coal, and its importance in understanding the weathering of coal. In this article, the effect of weathering on coal quality is discussed. Two Indian coals were kept for a period of 2 months, and different coal properties such as free swelling index (FSI), ash, and slurry pH were monitored at different intervals. This article suggests pH determination of coal slurry technique is more reliable for monitoring weathering of the Indian coal.