Charcoal Kiln Testing in Thailand

Bill Stewart

ITDG Stoves Project

One of the major parts of a Nonconventional Renewable Energy Project in Thailand has been to improve the efficiency of charcoal production. The Royal Thai Forestry Department is carrying out the work, and at a testing and training centre they have tested many of the best charcoal kilns from around the world under the same conditions. The following table is a translation from a brochure in Thai giving the results of their tests.

 

KILN NUMBER AND TYPE	VOL cu m	FIRING TIME hrs	%EFF'Y by wt	COST OF KILN US$
1 BRICK BEEHIVE	8	90	40	226
2 BRICK BEEHIVE	2	40	38	109
3 MUD BEEHIVE	7	70	38	38
4 MUD BEEHIVE	4	60	38	24
5 MUD BEEHIVE	2	40	38	22
5 BRAZILIAN CYLINDRICAL (brick)	8	75	35	157
7 MARK V METAL	5	42	30	652
8 MARK V METAL	3	23	31	522
9 OIL DRUM (vertical)	0.2	4	23	13
10 OIL DRUM (horizontal)	0.2	3	24	17
11 2 OIL DRUMS (horiz'l)	0.4	4	24	30
12 RICE HUSK BLANKET	0.7	8	32	-
13 SAWDUST BLANKET	0.7	18	33	-

 

The most interesting results are that the mud and brick kilns have considerably higher yields than the much more expensive metal kilns and that even small rice husk or sawdust blanket kilos have higher yields than oil barrel kilns - with no investment. The Royal Thai Forestry Department is presently running training programmes for charcoal makers and organising plantations of fast growing trees for charcoal production so that the production of charcoal will be an efficient system without destroying forests for the raw material. Construction details for the brick kilns are in the FAO Forestry Paper No 41 'Simple Techniques for Charcoal Making' 1983, available from authorised FAO Sales Agents, or directly from the Distribution and Sales Section, FAO, Via delle Terme di Caracalla, 00100 Rome, Italy.