coal briquettes analysis using different binding materials...

COAL BRIQUETTES ANALYSIS USING DIFFERENT BINDING MATERIALS, FOR K H Y B E R PAKHTUNKHWA COAL

Muhammad Daud*, Amad UllahKhan**, MuhammadBabar*** UET, Peshawar Pakistan. ** UET, Peshawar Pakistan. *** UET, Peshawar Pakistan.

Correspondence Author: engr. daud@gmail. com

Abstract: Coal samples from various places of Khyber Pakhtunkhwa are collected for making coal briquettes. For this purpose different compositions of Poly Vinyl Acetate (PVA), molasses, CaC03 and saw dust are used as binding materials to enhance the strength of coal briquettes and to increase its calorific value, keeping in view its ease of burning inpyro processing. Ultimate and proximate analysis of various samples are conducted, and the obtained data for the samples are than compared with each other and with the data obtained for the already existing coal briquettes available in Khyber Pakhtunkhwa market. By visiting the already existing coal briquette plants in the province, different parameters suchas calorific value, volatile matter, ash content etc. are noted for improving the quality of coal briquettes. The experimental results obtained during this research work will motivate the implementation of this research proj ect on a larger scale.

Keywords: Briquetting, Coal, Binding Agents, Harmful Gases.

1. Introduction

The modern world is facing the problem of energy crisis; especially our country has the alarming situation in this regard, which can be solved by harnessing the power of coal. Coal is abundantly present in Pakistan, and by using only few percent of these reserves, Pakistan can overcome these energy crises. Coal briquettes are made in order to improve the ranking of coal and increase its calorific value and make it easily combustible. The manufacturing of coal briquettes is aimed to increase the surface area of coal available for combustion. [1] Coal is a cheap fuel because of its abundant reserves, but it emits harmful gases and particulates, leaves ash when it burns, and contaminates the environment because of transportation. It is also hard to ignite as compared to gas or petrol fuels. Since long time people all over the world are trying to overcome these problems and to make it convenient and clean fuel. Briquetting is one of the approaches; the other approach is gasification that requires large scale factory, big investment and may produce secondary pollution. Briquetting is receiving high attention in developing countries where oil and gas are scarce and wood fuel supply is diminishing. [2]

2. Literature Review

Several attempts have been reported from time to time regarding the selection of binders and its cost in the manufacturing of coal briquettes. Early research

in this regard suggests the use of different types of pitch which includes coal-tar and petroleum. Coal-tar is considered to be the most economical however the latter is the best for consolidating small coal into a coherent form. Ammonium Nitro Humate is good binder. This binder has very good binding qualities and is very cheaply produced from Ammonium Hydroxide and Elbiston lignite and far more feasible to replace the Nitric Acid, used as a binder. [3] An increase in pitch content within the range tested (1025 wt %) improves significantly the impact and compressive resistance of the briquettes. Whatever the amount of pitch used, the mechanical resistance of the briquettes decreases during burning. In both cases (before and after activation) the mechanical resistance of the briquettes depends on the starting char and the pitch contentused. [4]

3. Problem Statement

The present hike in the prices of petroleum products diverts the attention of the people towards coal however its handling, low calorific value, and burning problems are the obstacles that create hesitancy in its utilization. The proposed study is focused to minimize the above stated problems.

3.1 Objective

The objective of the proposed work is to develop coal briquettes of high calorific value, high tensile strength (for easy transportation and handling) and

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Coal Briquettes Analysis using Different Binding Materials, for Khyber Pakhtunkhwa Coal

improved combustion performance.

3.2 Methodology

Different samples of coal and different composition of PVA, molasses, saw dust and CaC03 are taken for making of coal briquettes. These binding materials were added one by one and then together to the coal for making briquettes of different compositions. Once these briquettes got dry different tests are conducted for the ultimate and proximate analysis. The data obtained for these briquettes is then compared with one another and with the data obtained from already available coal briquettes in market. Furthermore tensile strength and better design of coal briquettes are investigated in order to get high tensile strength and high calorific value coal briquettes.

4. Conclusions

After conducting trials on different combination of coal with PVA, saw dust, molasses, CaC03 and clay it was found that presence of one full time fireman is must every time for cleaning ash, removal of clots and placing of briquettes in the furnace. Moreover, in curing with coal, the temperature could not be raised beyond 120°C without firewood coupling. Specialized persons are required for combustion of coal briquettes who could maintain the 3 T's (time, temperature and turbulence).

The primary air was not excessively provided to the tobacco barn that is why complete combustion could not be obtained. This is the reason why wood burning is practiced (illustrated in physically tested data). Also the percentage of fixed carbon contributes very much to easy ignition and calorific value, which is different for different places of coal in Khyber Pakhtunkhwa (illustrated in chemically tested data).

In Khyber Pakhtunkhwa market two main manufacturer of coal briquettes are available. The one manufactures under PTC supervision while the other is monitored by Phoenix Company.

PTC is using clay and CaC03 as binders, which is causing high clinker formation in the grate. On the other hand Phoenix is using CaC03, clay and silica,

but is having the same problem in the grate as PTC is facing. The clay and CaC03 also reduces the flame length and temperature, thus damaging the grate and reducing its life there by increasing its maintenance cost.

Clay and CaC03 are not combustible therefore it reduces the calorific value of the coal briquette, while PVA and molasses are organic compounds, which has its own calorific value and does not generates by products. The PVA also gives high tensile strength to the coal briquettes.

I f the secondary air is processed, we can also recover useful products like tar and naphtha, thus reducing the environmental hazardous compounds.

Future Outcomes

At national level Pakistan Tobacco Board (PTB) and at multinational level Pakistan Tobacco Corporation ltd (PTC) will adopt the project for tobacco curing. In conventional barns the wood burning is practiced, which is the main reason for deforestation and thus causing global warming. Thus by using the coal briquettes we can improve the quality of our environment which in turn will reduce the Global Environmental problems. This project is aimed to increase the efficiency of the current tobacco barns.

Acknowledgment

We are thankful to Maj(r) Mr. Sahibzaba Khalid (Chairman PTB) & Mr. Naseer Khattak, (Chief Planning Officer PTB), for their valuable suggestions and cooperation in this research.

References

[1] http://hubpages.com/hub/THAR-COAL-RESERVES-in-Pakistan(accessed on 1 st June 2010)

[2] http://www.hedon.info (accessed on 3rd June 2010) [3] Mehmet Yildirim and Gulhan Ozbayoglu (1997).

"Production of Ammonium Nitrohumate from Elbistan Lignite and its use as a coal binder" Fuel Vol. 76, No.5: 385-389.

[4] B. Rubio, M.T. Izquierdo, E. Segura (1999). 'Effect of binder addition on the mechanical and physicochemical properties of low rank coal char briquettes" Carbon37:18331841.

NFC-IEFR Journal of Engineering & Scientific Research

http://hubpages.com/hub/THAR-COAL-RESERVES-

http://www.hedon.info


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Table-II Summary of Physical Data for Coal Testing

S. No. Combination Formula Merits Demerits

1. Coal No. 3 PVA -1000 ml. CaCO3 -500gm

i. Fire quality good. ii. Maintained the required

temperature.

i. Clots of small size were formed.

2. Coal No. 1 PVA-1000 ml CaCO3_250gm

Compact, did not break during transportation.

i. Fire quality was not good. ii . Did not maintain the

required temperature. iii. Clots were also formed. iv. Did not catch the fire.

3. Coal No. 1 PVA-1000 ml CaCO3-500gm

i. Compact. ii. Do not break during

transportation and while placing in furnace.

i. Raise the temperature to required 130°F to 135°F.

ii . No clots were formed during burning also the merit of his combination.

4. Coal No. 1 PVA-1000 ml

i. Compact. ii. Do not break during

transportation and while placing in furnace

i. Burning quality not good. ii . Has very small flame.

iii. Meter reading drop from 130°Fto 125°F


i. Maintained the required temperature.

ii. Optimum compact, hardly bear the transportation load.

Clots were formed in negligible number.


Compact do not break. i. Do not raise the temperature to the required degree.

ii. Blocked the clots and ash. iii. Clots were being made.

1. Coal No. 3 PVA — 500 ml. CaCO3 -500gm

Very soft and broken during transportation so could not be loaded in furnace.

8. Coal No. 1 Coal No. 2 Coal No. 3 Molasses -500 ml Molasses -250 ml PVA —250 ml. PVA — 125 ml. CaC03

i . Compact. ii. Good burning quality.

iii. No clots formation or any other problem.

The only demerit noted was that it takes 4-5 days to become dry.

9. Coal No. 1 Coal No. 2 Coal No. 3 With saw dust in 500 gm and 1 kg in 10 kg coal PVA -1000 ml

When using saw dust in different doses with coal and PVA, no single merit was seen.

i. Too soft, during transportation and while putting in furnace.

ii. Blocked the mesh. iii. Burning was effected by

clots formation.

10. Coal No. 1 Coal No. 2 Coal No. 3 CaCO3 -500gm Clay-500 gm PVA -1000 ml

When using PVA-1000 ml with different formulation of clay & calcium carbonate no single merit was observed.

i. So soft that hardly be transported and put it in furnace.

ii. Very poor quality fire. iii. Hardly raised the

temperature of dry bulb to 100° but could not maintain the required temperature and the meter reading dropped.



Table-Ill Chemical Analysis of Coal Briquettes

Coal Briquettes Sample

Moisture Level (%)

Volatile Matter (%)

Ash Content (%)

Fixed Carbon (%)

Calorific Value (joules)

Tensile Strength (ton)

Coal No. 1 PVA - 1000 ml. 1.53 11.55 24 63 30463 0.15

Coal No. 1 PVA - 1000 ml. CaC0 3 -25Ggm

1.30 18.58 32 48.12 23268 0.18

Coal No. 1 PVA —1000 ml. CaCO 3 -500gm

1.7 14.85 47 36.45 22251 0.21

Coal No. 2 PVA-1000 ml. CaCO 3 -250gm

1.44 12.96 18 67.6 25893 0.17

Coal No. 3 PVA-1000 ml. 1.56 18.13 26 54.3 28354 0.16

Coal briquette available in market

CPTC) 1.51 13.15 58 32.12 16232 0.19

Coal briquette available in market

(Phoenix) 1.41 15.30 43 52.15 24523 0.14


coal briquettes analysis using different binding materials...

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