Coal making

Making coals from Cocos through charcoal brick kiln

by Ellaine Grace L. Nagpala

Coconut (Cocos nucifera) remains to be the top cultivated crop in the Philippines.  Out of the 12 million hectares of farmlands in the country, 3.1 million hectares of it is devoted to coconut production.  With the vast size of farmland devoted to coconut farming, it can be said that a large percentage of the country’s population still depends on coconut for their living.

Over 3.5 million coconut farmers are widely distributed in different parts of the country, mostly in Southern Luzon and in different parts of Mindanao.

To help the coconut farmers gain extra income while attending to their farm activities, the group of Engineer Rosella B. Villaruel of the Philippine Coconut Authority (PCA) in Region X1 came up with a charcoal brick kiln where coconut shells can be turned into quality charcoals.

What are kilns?
A kiln is a thermally insulated chamber used to harden, burn or dry materials, it could be utilized in drying and heating wood to produce firewood and charcoal, or in firing-materials used in ceramic-making.

Traditional means
Kilns were first utilized in Bago Oshiro, Davao City under the Philippine-German Coconut Project (PGCP) in 1995.

In the Philippines, charcoals are traditionally produced using drum kilns where a standard oil drum with an approximate capacity of 55 gallons is used. With the use of a drum kiln, charcoals can be produced from 600 pieces of split coconut shells.  However, charcoal workers encountered problems with regards to the operation, durability and efficiency of the drum kiln.

The charcoal brick kiln
The batch type brick kiln was fabricated as an alternative to the traditional methods of charcoal production and to ease the operations in charcoal making of the charcoal workers.

The brick kiln is made of 2”x4”x8” standard rectangular bricks, constructed in a dome-shape.  The kiln’s dome structure is for the purpose of optimal carbonization process.  Its inside has a base diameter of 1.2 meters and a net height of 1.10 meters with an approximate volume of 0.73 cubic meters.  This prototype kiln can accommodate approximately 3,000 pieces of average split shells.  This could be increased if the shells are semi-crushed.

The charcoals produced by the kiln from the coco shell wood passed the standard of a good quality charcoal which possesses a fixed carbon content of 86.5%, ash of 1.4%, volatile combustible matter of 9.6% and 2.5% moisture content.

The charcoal brick kiln is expected to last for five years or more with an initial investment of PhP 4,100 while the drum kiln has a serviceable life span of six months to one year, with each drum costing PhP 500.

One problem encountered by the charcoal workers with the drum kiln is its difficulty to operate.  Since metals are strong conductors of heat, the drum kiln becomes difficult to handle as it turns very hot during the process.

Moreover, the smoke being emitted under the drum becomes a nuisance to the workers.  As such, the brick kiln was designed to be user- friendly.

Bricks being resistors of heat makes the charcoal brick kiln easier to operate.  The kiln was also designed in such a way that it will suppress the heat pressure inside and prevent it form leaking outside the kiln.  In this way, the kiln will be convenient for the operators as they will no longer have trouble with the heat coming from the kiln.  Also, the smoke coming from the kiln not be a problem for the workers since a ‘nose’ for the emission of smoke is included in the structure which is strategically placed at the top of the kiln.  This way, it will be easier for the operators to recharge the kilns.

Time saving
The proper procedure for making good quality charcoals only requires 16 percent of the total time to produce charcoals with the brick kiln as compared to the drum kiln which requires 90 percent operation time.

With the charcoal brick kiln, 74 percent time more will be saved in charcoal making.  For a farmer who needs to attend to his farm and his family, and his other chores, the 74 percent time that can be saved means more time to attend to his tasks.

In general, this implies that the kiln is not only designed to increase the capacity of charcoal produced but also for the benefit of the worker. end

This article was based on ‘A comparative study between batch type brick kilns and drum kilns using decision tree analysis’ by Engineer Rose B. Villaruel and Mr. Kalvin Mesias Balucanag of the Philippine Coconut Authority in Region XI.  The Batch Type Brick Kiln was funded by the Philippine Coconut Authority and the Korea Institute of Industrial Technology.

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