Efficiency of coal washing process and Harrington desirability function

2021 ◽  
pp. 106-109
Author(s):  
D.A. Zavalishin
Keyword(s):  
Desirability Function ◽  
Ash Content ◽  
Laboratory Assessment ◽  
Clean Coal ◽  
Processing Scheme ◽  
Technological Efficiency ◽  
Washing Process ◽  
Washing Efficiency ◽  
Coal Washability ◽  
Scheme Evaluation

The technological efficiency of the coal washing process is traditionally assessed by the correlation between the practically achieved results of this coal washing at a coal dressing plant and the theoretically possible ones defined by the laboratory testing to define the coal washability. However, the laboratory assessment of coal washability is a labor-intensive process and cannot be used for on-line control. The article considers the possibility of introducing a performance evaluation indicator using parameters traditionally defined in operational control schemes. This indicator is based on the well-known function of qualitative process evaluation based on several parameters, i.e. the Harrington's desirability function. The proposed efficiency indicator was calculated based on the qualitative and quantitative parameters of washing thirty different coals using the conventional processing scheme. Evaluation of the proposed efficiency indicator was made by comparing it with the traditionally used efficiency indicators. The evaluation results showed that the proposed indicator is more informative, because it also allows to take into account the compliance of the ash content during washing with the specified parameter, as well as to evaluate the efficiency of the washing process more objectively than the traditionally used clean coal yield indicator. Within a given ash content of the clean coal there exists a correlation with the performance indicators recommended for assessment of the washing efficiency. Given the specific features of the desirability function, the indicator makes it possible to qualitatively assess the coal washing process and determine the optimal value..

A Design of an Inclined Froth Zone in Column Flotation Device to Reduce Ash Content in Clean Coal

2015 ◽  
Vol 35 (6) ◽  
pp. 281-294 ◽  
Author(s):  
Chao Ni ◽  
Guangyuan Xie ◽  
Bo Liu ◽  
Yaoli Peng ◽  
Jie Sha ◽  
...  
Keyword(s):  
Ash Content ◽  
Column Flotation ◽  
Clean Coal

The Flotation Process with High Intensity Conditioning and Cleaning for Fine Coal

2014 ◽  
Vol 1010-1012 ◽  
pp. 1636-1639 ◽  
Author(s):  
Ji Hui Li ◽  
Li Qiang Ma ◽  
Yan Zhao Li ◽  
Wen Jing Li ◽  
Jian Wei Yue
Keyword(s):  
High Intensity ◽  
Coal Sample ◽  
Ash Content ◽  
Clean Coal ◽  
Flotation Reagents ◽  
Flotation Process ◽  
Fine Coal ◽  
Percentage Points ◽  
Coal Slime

The properties analyzing of flotation feed sample told that this fine coal sample is high-ash and hard-to-float coal slime. The ash reduction comparison of the step-by-step release flotation test with high intensity conditioning (HIC) or not, and the comparison of flotation test with HIC and adding depressant were made. The results showed that HIC can significantly improve the flotation effect for high-ash and hard-to-float coal slime. Comparing with the traditional step-by-step flotation process, if it meets the demand of ash content is 10.00% and 8.00%, the clean coal yield with HIC will increase 18 and 29 percentage points respectively; comparing with the effect of floatation adding depressant, HIC has more help to reduce the ash content and increase the yield of clean coal. In addition, HIC will save a lot of flotation reagents.

scholarly journals Improving Coal Flotation by Gaseous Collector Pretreatment Method and its Potential Application in Preparing Coal Water Slurry

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 500 ◽  
Author(s):  
Shen ◽  
Min ◽  
Liu ◽  
Xue ◽  
Zhu
Keyword(s):  
Contact Angle ◽  
Coal Sample ◽  
Ash Content ◽  
Low Rank ◽  
Distribution Analysis ◽  
Low Rank Coal ◽  
Clean Coal ◽  
Pretreatment Method ◽  
Water Slurry ◽  
Coal Water Slurry

Low-rank coal is difficult to upgrade using conventional flotation methods due to its high hydrophilic properties. Thus, it is necessary to explore new methods for upgrading and utilizing low-rank coal. In this investigation, a gaseous dodecane pretreatment method was used to enhance the flotation performance of low-rank coal. Pore distribution analysis, FTIR (Fourier Transform Infrared Spectroscopy), and contact angle measurements were used to study the surface properties of the coal sample. Size distribution and float-sink test results indicated that the coal sample contained a lot of clean coal with low ash content, which could be used as a high quality raw material for making coal water slurry. FTIR, pore distribution analysis, and contact angle results showed that the coal was very hydrophilic due to the high concentration of -OH group and the large number of pores and cracks on the coal surface. The hydrophobicity of the coal sample was significantly improved by the gaseous dodecane pretreatment method. Clean coal with 67.2% combustible matter recovery and 10.5% ash content was obtained by gaseous dodecane pretreatment flotation method. Coal water slurry with 60% concentration was prepared using the flotation clean coal.

Experimental Research of Roughing and Cleaning Column Flotation of Difficult-to-Float High Ash Coal

2014 ◽  
Vol 1010-1012 ◽  
pp. 1603-1608 ◽  
Author(s):  
Jian Zhong Wang ◽  
Xian Bo Zhang ◽  
Hai Bin Qin ◽  
Li Tan
Keyword(s):  
Coal Sample ◽  
Ash Content ◽  
Clean Coal ◽  
Flotation Concentrate ◽  
Flotation Column ◽  
Flotation Tailing ◽  
Concentrate Yield ◽  
Coal Slime ◽  
High Ash Coal ◽  
Preparation Plant

Coal slime in Zhongcheng coal preparation plant in Baotou, Inner Mongolia, was analyzed. It is found that this coal sample is with high inner ash content and very difficult to float. It is hard to obtain low ash concentrate and high ash tailing with primary flotation. The live scale required ash content is 12.00% for total clean coal, 15.00% for flotation concentrate. It is found that the lowest concentrate ash content is 29.24% through exploring flotation experiments, which can not meet the producing requirement. Results of timed release flotation experiment show that when concentrate ash content is 15.00%, the theoretical concentrate yield is 24.36%, with 50.03% of flotation tailing ash content and 35.49% of combustible matter recovery. It can be concluded that the floatable grade of this coal sample is Very Difficult to Float. So flotation column is taken into account. The lowest concentrate ash content of roughing flotation by flotation column is 18.94%, which does not meet the requirement, either. Results of cleaning flotation of roughing flotation concentrate show that when the recycling pressure is 0.14 MPa, the concentrate ash content is 14.15% with a yield of 30.39%, which is satisfactory and can be referred to direct industrial production.

scholarly journals Studies on washability characteristics of low-volatile Indian coking coal by differential crushing

2020 ◽  
Author(s):  
Sugali Sekhar Chandra
Keyword(s):  
Specific Gravity ◽  
Coal Ash ◽  
Ash Content ◽  
Similar Degree ◽  
Clean Coal ◽  
Coking Coal ◽  
Relative Ease ◽  
Indian Origin ◽  
Two Parameters ◽  
Material Index

Abstract The effect of differential crushing on liberation characteristics has been studied for a low volatile coking coal of Indian origin through washability studies. Two parameters, namely “Index of Washability” (IW) and “Near Gravity Material Index” (NGMI), are used to describe the ease of washability. The ROM Coal is crushed to four different top sizes namely, 75 mm, 25 mm, 13 mm and 6 mm.On the basis of calculated IW it is observed that relative ease of washabiltiy increases with decrease in top size. From calculated IW values it may be said that this coal can be economically beneficiated using gravity process after crushing to -6 mm size. From the calculated NGMI values, the critical specific gravities have been estimated and the values for crushing to -75 mm,-25 mm,-13 mm and − 6 mm are 1.65, 1.68, 1.53 and 1.58 respectively. These critical specific gravity values suggest the separation at this specific gravity range is most difficult task using gravity methods. From NGMI analysis, it may be said that the NGMI values for coals crushed to -25 mm & -6 mm are identical (≈ 0.18) at 17% clean coal ash content. This suggests that with similar degree of difficulty, clean coal of 17% ash can be produced from these two different crushing sizes. In order to increase the yield for the clean coal of 17% ash, the decision on blending these two size coals may need to be taken.

On-line prediction of clean coal ash content based on image analysis

Measurement ◽  
2020 ◽  
pp. 108663
Author(s):  
Zhaoyu Qiu ◽  
Dongyang Dou ◽  
Deyang Zhou ◽  
Jianguo Yang
Keyword(s):  
Image Analysis ◽  
Coal Ash ◽  
Ash Content ◽  
Clean Coal ◽  
On Line

Study on Coal Separability for Wangcun Inclined Shaft in Chenghe

2013 ◽  
Vol 734-737 ◽  
pp. 1082-1085
Author(s):  
Xi Yuan Yang ◽  
Mei Li Du ◽  
Jin Ren Zhang ◽  
Jian Li Yang
Keyword(s):  
Particle Size ◽  
Coal Ash ◽  
Quality Characteristics ◽  
Ash Content ◽  
Test Results ◽  
Coal Seams ◽  
Clean Coal ◽  
Coal Quality ◽  
Heating Value ◽  
The Given

On the basis of the coal quality characteristics, the screening and drifting tests have been carried out to investigate the separability of the coals in the inclined shaft coal samples of Chenghe Wangcun coal mine. The results showed that the mine raw coal seams are medium ash, high sulfur and medium volatile coals. The screening test results showed that the water content and sulfur content of coals samples in each grade after sieving essentially remained the row coal characteristic. Heating value increased with the decrease of particle size, but ash content decreased with the particle size. The float-and-sink tests showed that when the given clean coal ash content was 10%13% and 15% respectively, the coal samples were in the extremely difficult degree, medium separability degree and medium separability degree respectively.

scholarly journals Cleaning of Dulmial-Punjab Coal by Froth Flotation

2017 ◽  
Vol 60 (3) ◽  
pp. 169-171
Author(s):  
Muhammad Shahzad ◽  
Zulfiqar Ali ◽  
Asim Siddique
Keyword(s):  
Particle Size ◽  
Froth Flotation ◽  
Maximum Yield ◽  
Ash Content ◽  
Impeller Speed ◽  
Clean Coal

This study was undertaken to assess the cleaning potential of Dulmial-Punjab coal by froth flotation.Release analysis was performed to determine the optimum flotation response of the coal. Number of batchflotation tests were performed to investigate the effects of various parameters such as particle size, impellerspeed, collector dosage, frother dosage and conditioning time on clean coal yield and ash content. It wasfound that maximum yield of 51.25% with 39.5% ash content was achieved at impeller speed, collectordosage, frother dosage and conditioning time of 1600 RPM, 1200 g/t, 200 g/t and 10 min, respectively.

scholarly journals Influence of curd particles washing on the composition of curd made of milk in which co aggregates were formed

2004 ◽  
Vol 49 (1) ◽  
pp. 75-86
Author(s):  
Snezana Jovanovic ◽  
Ognjen Macej ◽  
Jelena Denin-Djurdjevic
Keyword(s):  
Moisture Content ◽  
Technological Process ◽  
Significant Influence ◽  
Milk Protein ◽  
Whey Proteins ◽  
Ash Content ◽  
Free Basis ◽  
Heat Treated ◽  
Washing Process ◽  
Chemical Complex

The composition of curd A and curd B was investigated as influenced by the technological process known as curd washing after removing 1/3 or 1/2 of whey and replacing by the same volume of water at the drying temperatures of 42?C and 45?C, respectively. Milk used for experiments was heat-treated at 87?C/10 min, during which the chemical complex between casein and whey proteins (milk protein co aggregates) was formed. It is shown that the applied drying temperatures of 42?C (curd A) and 45?C (curd B) do not have significant influence on the curd composition. The curd A and B gained without washing of the curd had 50.91% and 50.60% of moisture, respectively. If the curd washing process is applied after removing 1/3 of whey, the resulting curd has higher moisture content, 52.27% and 52.63%, respectively for the curd A and B. The highest moisture content in the curd is noted in the curd gained when 1/2 of whey is replaced by water during washing treatment. The same tendency is noted for the moisture in fat- free basis (MFFB), the parameter used for cheese classification. Also, it is observed that fat, protein and ash content are lower in the curd A and B when the curd washing process is applied than in the curd produced without the curd washing process. However, regardless of the increased moisture content of the curd gained by washing process, it is possible (even from heat-treated milk in which coaggreagates are formed) to achieve the average MFFB typical for semi-hard cheeses of Dutch type, by further technological processes such as molding, pressing, salting and ripening.

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