The Journal of Energy and Environmental Science. 132 (2017) 663-668 https://sites.google.com/site/photonfoundationorganization/home/the-journal-of-energy-and-environmental-science Original Research Article. ISJN: 4382-1729: Impact Index: 5.68

The Journal of Energy and Environmental Science

Ph ton

Influence of Relative Humidity and Temperature on Grindability of Pakistani and Afghani Coals Sumaira Kanwal*, Hafiza Sana, Shafqat Nawaz, Shahid Munir Lecturer, Centre for Coal Technology, University of the Punjab, Pakistan Article history: Received: 01 June, 2017 Accepted: 05 June, 2017 Available online: 12 September, 2017 Keywords:

Pakistani Coal; Grindability; Relative Moisture content; Coal Pulverization

Humidity;

Abbreviations: HardgroveGrindability Index (HGI), Xray fluorescence (XRF) Corresponding Author: Kanwal S.* Lecturer Email: sumaira.cct (at) pu (dot) edu (dot) pk Sana H. Research Officer Nawaz S. Professor

coals, due to increase in the atmospheric relative humidity from 65% to 82%,reduce the HGI value up to 4.76 in the case of hard coals while it increased the HGI value up to11.85 in the case of soft coals. The magnitude of change in HGI with change in total moisture content after air drying of four coals under study was found to be somewhat similar. However, the magnitude of change in HGI with change in total moisture content on as received basis of a softer coal was found to be higher compared to that of harder coals. Countries like Pakistan have temperatures touching -2°C in winter and 47°C in summer. The relative humidity also changes from 60.2% to 80.5% during different weather conditions. Accordingly equilibrium moisture content of coal also changes with change in the relative humidity/atmospheric temperature. The purpose of the present research is to measure the impact of equilibrium moisture contentof Pakistani and Afghan coals under different relative humidity conditions on its HGI, which will be helpful for the calculation of specific energy requirement to mill the sample.

Munir S. Professor

Abstract Grindability of coal is a composite physical property which is generally measured by determining its Hardgrove Grindability Index (HGI). In the present study, the effect of change in total moisture content on as received and air dried basis of four different coals(from Pakistan and Afghanistan) on the HGI was studied. The results have shown that an increase in the total moisture content upto 8.11% on as received and air dried basis of

Citation: Kanwal S..*, Sana H. Nawaz S., Munir S., 2017. Influence of Relative Humidity and Temperature on Grindability of Pakistani and Afghani Coals: The Journal of Energy and Environmental Science. Photon 132, 663-668 All Rights Reserved with Photon. Photon Ignitor: ISJN43821729D858812092017

1. Introduction The choice of a coal for utilization in the industrial sector depends not only on its price per million BTU, its proximate analysis, and its sulphur content but also on the cost of its pulverization to the required size. The grind ability of coal is a composite physical property which reflects its hardness, strength, tenacity and fracture. It affects the energy cost of coal pulverization to the required size needed for its utilization (Özbayoğlu et al. 2008). The methods for measuring coal grind

Ph ton

ability are based on grinding the coal of requisite size in a standard mill for specific number of revolutions, estimating the amount of new surface by screen analysis and then comparing this amount of new surface with those for standard coal samples (Speight 2012, Shahzad et al. 2014, Rafaqat et al. 2015). The most common methods used for measuring grind ability is that of HGI which is useful in predicting the capacity, performance and energy requirement of the grinding machinery. Easy-to-

663

Figure 1: Effect of relative humidity on total moisture of coals: Where Low moisture afghan coal= LMAC, High moisture afghan coal = HMAC, Afghan coal= AC, Lakhra coal= LC 16

14 Total moisture

12 10 8

○ LMAC □ HMAC

6 4 2 0 60

65Relative 70 humidity 75 % 80

85

2. Objective of Research/Justification of Research

pulverization of coal under different relative humidity/ atmospheric temperature conditions which shall advance the scientific domain. Figure 2: Effect of relative humidity on air dried loss moisture in coals. Legend abbreviations same as in Figure 1

90 80

○ LMAC □ HMAC ∆ AC × LC

70

HGI

grind coals have high HGI numbers while difficultto-grind coals have low HGI numbers. Accordingly, coals having HGI values below 40 are classified as very hard coals, those having HGI value from 40 to 60 as hard coals, those with HGI value from 60 to 80 as medium hard, those with HGI value from 80 to 100 as soft coals and those with HGI value from 100 to 120 as very soft coals. For different coals HGI numbers depend upon their rank i-e its petrography, proximate analysis, ultimate analysis and type of inorganic mineral matter present in different coals.Sengupta (2002) developed an equation by regression analysis to predict HGI from proximate analysis by taking more than 300 coal samples from all over India. This change in moisture content of a specific coal changes its HGI and accordingly the energy required for its pulverization to the desired size (Deniz and Umucu 2013, Deniz 2014). As Pakistan and Afghanistan are located in tropical region where weather variations are significant throughout the year and information in literature about the effect of climatic condition on HGI of Pakistani and Afghan coal is not available. The purpose of 1. this investigation was to study the HGI of four coals under different climatic conditions as these will result in the change in moisture content of these coals.

60 50 40

30 0

4

Total8moisture,12%

16

Methodology The 50 Kg of each sample was collected from the coal mine sites following standard sampling procedures ASTM D2234/D2234M-07. By applying conning & quartering technique on each sample according to ASTM D346-04 method, the representative samples were obtained. Each representative sample was thoroughly mixed and reduced to particle size -16 +30 mesh, by doing so the sample was placed on a 1.18mm (16 mesh) sieve. The retained sample i.e. +1.18mm was further ground until the whole material was passed from 1.18mm (-16 mesh). The -1.18mm sample was further sieved through 600µm (30 mesh) sieve to get -16+30 mesh fraction for the determination of HGI. The -600µm (-30 mesh) was discarded and +600µm (+30 mesh) was used for determining the HGI values according to ASTM D293-93. The proximate analysis of found coals was carried out using standard ASTM producer ASTM D-3173, ASTM D-3175ASTM D-3174 and ASTM D-388 for moisture. Air drying of coal samples was achieved using ASTM D-3302 until the constant weight was achieved. XRF analysis of ground coal was carried out using XRF analyzer. Table 1 & 2 show the results of proximate analysis and XRF analysis of coal ashes.

This study will generate the baseline data of physicochemical characteristics of Pakistani and Afghani coals such as proximate analysis,grindabilityand XRF analysis. Results of the present study will help for assessment of precise energy requirements for Ph ton

664

Figure 4: Effect of moisture on HGI of coals after air drying. Legend abbreviations same as in Figure 1

Figure 3: Effect of total moisture on HGI of coals. Legend abbreviations same as in Figure 1.

90 95

80

○ LMAC □ HMAC ∆ AC × LC

65 55

60

HGI

75

○ LMAC □ HMAC ∆ AC × LC

70

50 40

45

30

35 2

Air 4 dried coal 6 moisture, 8 %

60

10

For each test, 50g sample of coal having size-16 + 30 mesh was taken in the grinding unit of standardized HGI machine as per ASTM D-409. The mouth of the static grinding unit was closed and adjusted by using four disks with a grove. Grinding unit was inserted in the upper rotating part of HGI machine. The apparatus was then set to rotate for 60 revolutions for one experiment. The sample in the grinding mill was then collected and any powder sticking to the surface of the grinding mill was also collected with the help of the brush. The sample was placed in the sieve of 200 mesh size which was shaken in a sieve shaker for about 5 minutes. The sample which passed through 200 mesh size sieve was taken and weighed. The HGI was read from the calibration chart prepared by making use of four standard samples provided with the machine by adopting the same procedure as for determination of HGI mentioned above(Speight 2012). 2. Results and Discussion Figures 1 to 2 show the effect of relative humidity on total moisture (as received basis),and air dried loss moisture in coals. Figure 3 & 4 explains the effect of total moisture and air dried moisture of coals on HGI. Figure 5 explains effect of relative humidity on HGI.

65 75 % Relative70Humidity

80

85

The results indicate a considerable increase in the total moisture content of four coals under study with an increase in the atmospheric relative humidity. This could be due to the fact that coal is hygroscopic in nature and rapidly reaches equilibrium with the prevailing atmospheric humidity. The magnitude of change in air dried loss with change in the atmospheric relative humidity, given in Figure 2, was noticed to be about one third to half of the change in total moisture content (as received basis) with the respective atmospheric relative humidity given in Figure 1. This appears to be because of the fact that air drying was carried out in the air drying oven maintained at 40◦ C while atmospheric temperature varied between 24◦C and 36◦C during the course of this study. Figure 5: Effect of relative humidity on HGI of air dried coals. Legend abbreviations same as in Figure 1 90

80

○ LMAC □ HMAC ∆ AC × LC

70 60

HGI

HGI (air dried)

85

50 40 30 60

65 75 % Relative70Humidity

80

85

Change in HGI of four coals (as received) with an increase in atmospheric relative humidity from 65% to 82%, given in Figure 3, indicated a reduction in HGI value by 2.51 to 4.76 in the case of hard Afghan coals (HGI from 40 to 60) while it showed an increase in the HGI value by 11.85 in the case of soft Lakhra coal (HGI from 80 to 100). Similarly change in HGI of four coals (air dried) with increase in atmospheric relative humidity, given in Figure 5, indicated a reduction in HGI Ph ton

665

value from 4.54 to 5.65 in the case of hard coals while it exhibited an increase in the HGI value by 4.89 in the case of a soft coal. An increase in total moisture content (as received basis) from 6.74% to 8.11% resulted a decrease in HGI value from 2.51 to 4.76 in the case of hard coals while it indicated an increase in HGI by 11.85 in the case of a soft coal. It may thus be concluded that an increase in the atmospheric relative humidity from 65% to 82% has enhanced the total moisture content of coals up to 8.11% which resulted in the reduction of HGI value up to 4.76 in the case of hard coals while it showed an increase in the HGI value by 11.85 in the case of a soft coal. The results of the present study are in agreement with the findings of (Özbayoğlu et al. 2008) concluded that HGI reduces with the increase in moisture content. These authors also observed that moisture content contributes positively to the grinding of low rank coals which supplement finding of this study in the case of Lakhracoal which obviously is a low rank coal as can be seen from the results of its proximate analysis given in Table 1. The results of present investigation are also supported by findings of

(Vuthaluru et al. 2003) who studied the change in HGI with change in the moisture content of three Australian coals as a result of change in the atmospheric temperature and humidity. They found that reduction in the moisture content of coals by oven drying at 40°C increased the HGI value in the case of two coals while reduced the HGI value in the case of one coal. The experimentally determined HGI values of four coals were found to be in agreement with the values computed from the results of their proximate analysis(Sengupta 2002) given in Table 1. Similarly, HGI results of four coals are also supported by the XRF analysis of their ash,given in Table 2 which indicates that lower Al2O3 and higher Fe2O3 coals give higher values of HGI and vice-versa (Jorjani et al. 2008). Similarities and dissimilarities in the results of present study and those of other researchers mentioned above may be attributed to the fact that different coals have been investigated in different studies while coals is a heterogeneous substance and its HGI is dependent on its maturity, petrography, and mineral impurities(Sengupta 2002, Chelgani et al. 2008).

Table 1: Proximate Analysis and HGI of boals Proximate Analysis (as received basis) Coal Total Volatile Fixed Ash% Moisture % Matter% Carbon% LC 10.98 30.55 37.4 21.07 AC 9.97 28.02 10.93 51.07 LMAF 6.215 28.81 28.13 36.85 HMAF 11.77 26.11 15.95 46.16 Table 2: XR Fanalysis of ash obtained from coals Constituents of Ash% Coal Source Fe2O SiO2 Al2O3 3

LC AC LMAF HMAF

41.05 45.48 50.22 45.69

15.03 27.39 25.55 20.84

17.76 5.6 4.66 6.68

86.85 46.46 52.02 50.91

CaO

MgO

K2O

Na2O

5.94 4.06 3.83 6.19

1.42 2.02 1.93 2.35

0.39 1.32 1.92 1.26

0.18 0.73 0.99 0.84

Conclusion The following conclusions can be drawn from this study: 1. Influence of relative humidity and temperature was measured ongrind ability of Pakistani and Afghan coals. It was found that an increase in the atmospheric relative humidity from 65% to 82% has enhanced the total moisture content of coals up to 8.11% which resulted in the reduction of HGI value up to 4.76 in the case of hard coals while it showed an increase in the HGI value by 11.85 in the case of a soft coal. Similarly, change in air dried coal samples, reduction in HGI value of hard coals from 4.54 to 5.65 while it exhibited an increase in the HGI value by 4.89 in the case of a soft coal. Ph ton

Estimated HGI

2. Total moisture content (as received),air dried loss and Total moisture content(air dried) of a coal is affected by the atmospheric percentage relative humidity which influences its Hardgroove Grindability Index. This consequently affects input required for coal pulverization which is substantial varying from 5KWh/ton to 15 KWh/ton. 3. Hardgroovegrind ability index of a coal can reasonably be predicted by making use of its proximate analysis results. 4. Lower Al2O3 and higher Fe2O3 contents in a coal ash give higher values of HGI and vice-versa.

666

Research Highlights Physicochemical characterization of coals was done. Impact of relative humidity and temperature on the HGI of four coals selected from Pakistan and Afghanistan was measured and it was found that atmospheric relative humidity has a direct impact on the grind ability of coals. Limitations This study determined the Influence of relative humidity and temperature on grindability of Pakistani and Afghan coals. It is focused on two coals only due to limited resources because it was not a funded project.

Deniz V., Y. Umucu., 2013. 'Interrelationships between the bond grindability with physicomechanical and chemical properties of coals,' Energy Sources, Part A: Recovery, Utilization, and Environmental Effects Vol. 35, No. 2, pp. 144-151. Jorjani E., J.C. Hower, S.C. Chelgani, M. A. Shirazi and S. Mesroghli (2008). 'Studies of relationship between petrography and elemental analysis with grindability for Kentucky coals,' Fuel Vol. 87, No. 6, pp. 707-713. Özbayoğlu G., A. M. Özbayoğlu and M. E. Özbayoğlu (2008). 'Estimation of hardgrove grindability index of Turkish coals by neural networks,' International Journal of Mineral Processing Vol. 85, No. 4, pp. 93-100. Rafaqat U., J. Akhtar, N. U. Sheikh and S. Munir (2015). 'Cleaning of Dukki (Baluchistan) coal by oil agglomeration process,' International Journal of Oil, Gas and Coal Technology Vol. 9, No. 1, pp. 79-88.

Recommendations It is recommended to study the influence of relative humidity and temperature on grindability of different coals from different provinces of Pakistan and make a comparison with Afghan coal as weather conditions of both countries are almost same. Funding and Policy Aspects

Sengupta A. N. (2002). 'An assessment of grindability index of coal,' Fuel Processing Technology Vol. 76, No. 1, pp. 1-10. Shahzad, K., S. Kanwal S. Nawaz, N. Sheikh, S. Munir (2014). 'Effects of moisture and coal blending on the hardgrove grindability index of Pakistani coals,' International Journal of Coal Preparation and Utilization Vol. 34, No. 1, pp. 1-9. Speight, J. G. (2012). Chemistry and Technology of Coal. New York, CRC Press, pp.

It was not a funded project. Author’s Contribution and Competing Interests The authors Sumaira Kanwal and Hafiza Sana designed the research, completed the experiment and wrote the paper. Dr.Shafqat Nawaz provided some ideas on the paper and edited the paper. Dr. Shahid Munir checked the results and the entire manuscript.

Vuthaluru, H., R. Brooke, D. Zhang and H. Yan (2003). 'Effects of moisture and coal blending on hardgrove grindability index of Western Australian coal,' Fuel Processing Technology Vol. 81, No. 1, pp. 67-76.

Biographical Notes of Authors: Ms. Sumaira Kanwal

Acknowledgement The authors acknowledge the DG cement industry for the contribution of conducting XRF analysis of samples. References Chelgani S.C., J. C. Hower, E. Jorjani, S. Mesroghli and A. Bagherieh (2008). 'Prediction of coal grindability based on petrography, proximate and ultimate analysis using multiple regression and artificial neural network models,' Fuel Processing Technology Vol. 89, No. 1, pp. 13-20. Deniz V., 2014. 'The effects of moisture content and coal mixtures on the grinding behavior of two different coals,' Energy Sources, Part A: Recovery, Utilization, and Environmental Effects Vol. 36, No. 3, pp. 292-300.

Ph ton

Ms. Sumaira Kanwal did her M.Sc. in Coal Technology from Centre for Coal Technology, University of the Punjab in 2008 and secured Gold Medal and M.Phil in Environmental Sciences in 2009 from College of Earth & Environmental Sciences,University of the Punjab. She joined Centre for Coal Technology in 2009 as Research Scholar and was later promoted as lecturer in 2011 base upon her exceptional performance. She is currently undertaking her Ph.D studies. She has published 6 journal papers.

667

Ms. Hafiza

Ms. Hafiza Sana did her M.Sc. in Coal Technology in 2010 and M.Phil in Coal Technology in 2016 from Centre for Coal Technology, University of the Punjab. She joined Centre for Coal Technology in 2013 as Research Officer. She has published 3 journal papers. She has supervised 12 research thesis of M.Sc. Coal Technology students. Professor Dr. Shafqat Nawaz

Professor Dr. Shafqat Nawaz has been a renowned Professor of Chemical Engineering in University of the Punjab for the last four decades. He completed his Ph.D in 1973 from University of Leeds, UK. He has worked as Director, Institute of Chemical Engineering & Technology and Centre for Coal Technology in University of the Punjab. He has published 35 research papers. Prof. Dr. Shahid Munir

Prof. Dr. Shahid Muniris the leading scientist in the discipline of Energy and Environmental Engineering in Pakistan who has 23 years of industrial, teaching and research experience. He is currently serving University of the Punjab as Professor in Chemical Engineering and Director in Centre for Coal Technology. He did his Ph.D in chemical Engineering from University of Leeds, UK. He has published 27 research papers. Ph ton

For publications/ Enquiries/ Copyrights: Email: [email protected] 668

Ph ton

4 hours ago - Lecturer, Centre for Coal Technology, University of the Punjab, Pakistan. Article history: Received: 01 June ... the year and information in literature about the effect of climatic ..... Environmental Sciences in 2009 from College of.

941KB Sizes 0 Downloads 342 Views

Recommend Documents

Ph ton
2012) . The taste, color, odor, and turbidity were observed organoleptically. Table 1: Locations of wells under consideration. Well NO. Location. 1. Kafr El Ais. 2. Kafr El Ais. 3 ... However, the World. Health Organization (WHO, 2011) does not list

Ph ton
16 hours ago - the current study is agreed with the data obtained by Varank .... recovery a review. Energy ... a laboratory specialist in water quality, fish culture.

Ph ton - MA Zayed
Jan 19, 2017 - 39.2. 60. 8. 90. 60. 330. 0.310. 0.01. 0.60. 0.20. 0.20. 23. 2. 104. 41.65. 100. 12. 80. 50. 420. 0.394. 0.05. 0.40. 0.16. 0.10. 25. 3. 76. 41.6. 40. 6.

Ph ton
Sep 4, 2017 - Email: kalpna.bhandari ( at ) gmail ( dot ) com. Citation: Bhandari K*., 2017. Proline: .... Enquiries/ Copyrights: Email: [email protected].

Ph ton - MA Zayed
Jan 19, 2017 - shows mixture of three types of water with variable concentrations of ... usage and consumption, it can be a renewable or a non-renewable ...

Ph ton
6 hours ago - Email: srrohi ( at ) gmail ( dot ) com. Abstract ..... The leaves are good for piles, kidney ... carminative, stomachic; good for the teeth and the.

Ph ton
May 11, 2017 - analysis of fluopyram, trifloxystrobin and its metabolite in vegetables (tomato, and cowpea) and fruits (pear, grape, apple, and watermelon). The.

Ph ton
1 day ago - The Journal of Bioprocess Technology. 103 (2017) 523- ... Department of Medical and Molecular Biotechnology College of Biotechnology Al-Nahrain University, Iraq ... hydrocarbon contaminated soil in Iraq and showed good.

Ph ton
3 days ago - Journal of Agricultural Economics and Sustainable Development Photon 106 (2017) 219- ..... The formal and informal financial systems co-exist.

Ph ton
Dec 6, 2016 - https://sites.google.com/site/photonfoundationorganization/home/ ...... The paper deals with the medicinal plants .... Internet Book Distributors,.

Ph ton
High transformation frequency was achieved by using 3-day-old precultured leaf explants. ... alkaloids, saponins and steroids which contained high level of antioxidant activity (Dzomba and. Mupa, 2012). ... stemmed, tendril climbers, leaves are alter

Ph ton
undertaking a GHG emissions assessment or other calculative activities denoted as carbon accounting. Once the size of a carbon footprint is known, a strategy can be ..... By far the biggest contributor is the shoe's raw material. "For most Timberland

Ph ton
4 hours ago - Email: tagrawal02 ( at ) gmail ( dot ) com ... Araucaria is the genus of the great values. They ... grows well in the lower altitudes with good.

Ph ton
30 mins ago - Director. Email: pef_unp ( at ) yahoo ( dot ) com ( dot ) ph. Abstract ... Poles.html), house builders and furniture makers recognize bamboo for its ...

Ph ton
Nov 26, 2016 - b Department of Chemistry, S. N. Art's, D.J. Malpani Commerce and B. N. Sarada Science ... d Department of Pharmacognosy & Phytochemistry, Amrutvahini College of Pharmacy, Sangamner, MS, India. ..... the application of an analysis of v

Ph ton
Abstract. Many different animals and amphibians play an important role in the life cycle of different species of nematode parasites as a paratenic or intermediate or final hosts. This study was design to identification the intestinal nematode that fo

Ph ton
May 17, 2017 - it also leads to quick recovery of the infected rats. Citation: Adebolu T.T.* ... are lost during episodes of diarrhoea (Victora et al.,. 2000). ORS is ...

Ph ton
Jun 28, 2017 - Recurrent pericoronitis with attendant symptoms;. 3.Periodontal pocketing affecting ... of auto-transplantation. 4.For prosthetic considerations. 5.

Ph ton eBooks
Email: [email protected] ... specialization in Fisheries) from University of Kashmir Srinagar India. ... processing, storage, transport, or marketing. ..... solution). The term "partition coefficient" is now considered obsolete by IUPAC,.

PH METER.pdf
There was a problem previewing this document. Retrying... Download. Connect more apps... Try one of the apps below to open or edit this item. PH METER.pdf.

hep-ph
Aug 19, 2010 - At a proton-proton collider, QBHs will be ... Classical black hole solutions are known in this .... Quantum black holes produced at a proton-.

Ph. D.
sa réactivité et son aptitude à répondre avec égale bienveillance, quelle que soit la pertinence de la question. Sa manière d'appréhender les mathématiques m'inspirera toujours. Je suis évidemment .... de densités de lois exponentielles, al

Partitura vois sur ton chemin.pdf
œ. j. œ. œ œ œ œ. sens au coeur de la. ̇. ̇. mains au. ‰. œ. œ. œ. œ. œœ. ‰. œœ. œ. œ. œ. œ. œ Œ œ Œ. VOIS SUR TON CHEMIN. B. COULAIS. Page 1 of 5 ...

635810 Ph
(5) Deficiency of thyroxine results in Simple goiter, Myxoedema and cretinism. Excess .... phenolphthalein, methyl orange, sodium carbonate salt, zinc granules,.