Charcoal production for carbon sequestration

Charcoal production for carbon sequestration

Gustan Pari Djeni Hendra Dadang Setiawan Mahpudin Saepuloh Salim Soleh Mad Ali (Forest Products Technology Research and Development Center)

Kiyoshi Miyakuni Nobuo Ishibashi (Japan International Cooperation Agency)

April, 2004 Demonstration Study on Carbon Fixing Forest Management in Indonesia

Table of contents I. Background …………………………………………………………..……….. 4 II. Purposes and methodologies

……………………………………………. 6

1. Purposes 2. Sites for field trials 3. Comparison of carbonization efficiency: carbon yield 4. Comparison of cost efficiency 5. Estimation of carbon fixation potential by charcoal production

III. Types of kilns for field trials

…………………………………………… 12

1. Nonpermanent kiln 1-a. Earth pit kiln 1-b. Modified earth pit kiln: Brick floor and galvanized iron sheet for closing kiln 1-c. Sawdust mound kiln 2. Movable kiln 2-a. Single drum kiln: Air inlets at the side of drum 2-b. Single drum kiln: Air inlets at the bottom of drum 2-c. Double drum kiln 3. Permanent kiln: Yoshimura kiln 4. Kiln for producing sawdust charcoal: flat kiln

IV. Comparison of carbonization efficiency …………..………………… 32 1. Nonpermanent kilns 2. Movable kilns: drum kilns 3. Permanent kiln: Yoshimura kiln 4. Flat kiln for sawdust charcoal 5. Comparison of carbon yield

V. Comparison of cost efficiency …………..……………………..………… 44 1. Earth pit kiln and brick floor kiln 2. Earth pit kiln at sawmill 3. Drum kiln 4. Yoshimura kiln 5. Flat kiln 6. Comparison of costs for producing charcoal and carbon

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VI. Evaluation of viability of charcoal production for CDM projects …………..………………… 56 1. Carbonization of wood material from shrubs or secondary forests 1-a. Total amount of charcoal and carbon produced in West Java experimental sties 1-b. Carbonizing wood material from shrubs or secondary forests 2. Wood residues from plantation forests (Acacia mangium) 3. Wood residue from sawmill

VII. Conclusions ……………………………………………..………..……….. 67 1. Factors which affect on carbon yield and cost efficiency 2. Viable project types for carbon sequestration

Acknowledgements ……………………………………………………..…….... 68 References ………………………………………………………………..…….... 69

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I. Background In Indonesia, Logging operations in man-made and natural forests, wood industries (plywood factories, sawmills, pulp mills, etc.) and other activities are generating various types of wood residues and large amount of such residues are left unused. Recycling them has been an important issue. According to the data provided in Okimori, et al., (2003), from Acacia mangium plantations in South Sumatra, 23.39% of total aboveground biomass becomes wood residue (56.4t/ha from 241.1t/ha) after taking out materials for pulp. As shown in Photo 1 and 2, those residues are abandoned in the field. It will decompose and can be the source of CO2 emission. At pulp mills, although wood bark is utilized as fuel for a generator, large amount is still abandoned (Okimori, et al., 2003).

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Photo 1 and 2 Wood residue left in the plantation site (in PT. Musi Hutan Persada, South Sumatra)

Slabs from sawmills and plywood factories are often burned or thrown out to the river and sea (Ohara, et al., 1996a and Ohara, et al., 1996b). It is said that 20 to 30 percent of wood material becomes sawdust in sawmill operations (Kikata and Sri Nugroho, 1994). Often it is piled up beside the sawmill and burned (Photo 3). It can also cause water pollution if the sawdust hill is located beside a river. If the sawdust is left decomposed or burned, it causes carbon emission. Therefore, it is necessary to develop ways to utilize sawdust and reduce pollution and carbon dioxide emission. There are several ways to utilize sawdust. For example, (1) Production of compost for agriculture (2) Mushroom cultivation (3) Material for activated charcoal (produced using a flat kiln) (4) Briquette charcoal (5) Material for mesquite coils 4

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(6) Fuel for cooking (in Central and East Java)

Photo 3 Sawdust-hill beside sawmill (Bogor District, West Java) Unused sawdust is often burned at the sawmill. Although the above methods have already been implemented in Indonesia, there is still a large amount of sawdust un-utilized because of a limited market, location of sawmills (small scale sawmills are scattered in the whole Indonesia), the difficulty in controlling the quality of products, and so on. Producing compost can be a good way to return nutrients in wood residue to the soil. This method, however, is still not common because fermentation of sawdust is difficult. One of the countermeasures for recycling those residues is production of charcoal for fuel, soil conditioner, water purification and other purposes, and at the same time, contributing to carbon sequestration or CO2 emission reductions (Seifritz, 1993; Ogawa, 1997; Kurosu and Sugiura, 1997, Glazer et al., 2002; Okimori et al., 2003). Charcoal is a very stable substance (Seifritz, 1993: Glazer et al., 2002 and Ogawa, 2003). According to the experiments by Ogawa (2003), half-life of charcoal (carbonized in 1000 degree Celsius) was 1,029 years (if exposed to ozone: 0.005ppm). Charcoal carbonized under lower temperature was more stable under the higher concentration of ozone in the air. Charcoal can hold pure carbon inside it for a long time and playing a role as a carbon sink. The efficiency for carbonization, however, must be examined. In the carbonization process (pyrolysis), considerable amount of carbon in wood material is gone to the air. The CO2 emission from charcoal production must be reduced. The cost efficiency also must be considered for the implementation of carbon fixing project by charcoal production.

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II. Purposes and methodologies 1. Purposes This report is to compare several types of kilns and find out effective charcoal production methods for CDM projects, and evaluate viability of charcoal production for carbon sequestration. (1) Comparison of efficiency among several types of charcoal production method i. Efficiency for carbonization (carbon yield): The amount of CO2 emitted in the process of carbonization must be decreased. ii. Cost efficiency: costs for producing 1 ton charcoal or carbon: Not only the costs for producing charcoal, but also for carbon should be analyzed. (2) Estimation of potential for carbon fixation potential by charcoal production: How much carbon can be stored in charcoal? The amount of wood residue must be estimated. Is must be mentioned that charcoal production is not admitted as CDM project at present. This report is only for demonstrating the viability and efficiency of charcoal production for carbon sequestration. 2. Sites for field trials (1) West Java: See Fig.1 for the map a. Forest Product Research and Development Center in Bogor city b. Shrubs and secondary forest area under the jurisdiction of PT. Perhutani, Unit III, KPH (forest district) Bogor: After shrubs or secondary forests were cut for land preparation, using the wood material, charcoal was produced. Charcoal production was conducted mainly from July until October 2001. Some of the produced charcoal were clashed and put in the planting holes for accelerating the growth of seedlings. After charcoal production, Acacia mangium (in Marbaya), Shorea leprosula (in Ngasuh) and Pinus merkusii (in Cianten) were planted at three locations from the end of 2001 until the beginning of 2002. Many local residents had been experienced charcoal making before this project started. Earth pit kiln is the common method in this area. i. <Maribaya>: RPH (ranger district) Maribaya, BKPH (forest subdistrict) Parungpanjang: Charcoal making is common in this area. ii. : RPH Ngasuh, BKPH Jasinga: Charcoal making is common in this area. Among three sites in West Java, local residents in this area were the most skilled makers. iii. : RPH Cianten, BKPH Leuwiliang: Only one person in villages around this site had been experienced charcoal making.

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Java Island

1

Fig.1 Location of field trial sites in West Java

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Notes: (1) Maribaya: Acacia experimental site (2) Ngasuh: Shorea experimental site (3) Cianten: Pinus experimental site

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Fig.2 Location of Toho experimental site of Yayasan Dian Tama

West Kalimantan

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(2) East Kalimantan: See Fig.2 for the map Toho experimental site of Yayasan Dian Tama (Its office is located in Pontianak, Capital city of West Kalimantan), local NGO for community development. In the experimental site, several types of kilns had been constructed. Brick kiln (called Sugiura kiln), Yoshimura kiln, drum kiln and other types had been build there. Some of them were introduced by “Kokusai Sumiyaki Kyoryoku Kai”, Japanese NGO of which main members are involved in charcoal industry. Charcoal are utilized for animal husbandry (pigs and chickens); cleaning the hog pen, mixed with feedstuff for good taste of eggs. Paddy, beans and other crops are planted and compost mixed with charcoal is utilized as fertilizer. Laban trees (Vitex pinnata) were planted for material of charcoal (There once had been cooperation study with Center for International Forest Research for planting Laban trees at alang-alang (Imperata cylidrica) field.). Trials under cooperation with this JICA project for carbonization using Yoshimura kiln (explained later about this kiln) had been conducted in October 2003. 3. Comparison of carbonization efficiency: carbon yield In the process of carbonization, considerable amount of carbon is emitted to the air. Seifrtiz (1993) stated that approximately 50% of the carbon in the biomass (mainly the trunk and the thicker branches) can be extracted in the form of charcoal. Glazer (2002) compiled previous literatures and calculated average carbon yield of various types of kilns including laboratory furnace, and stated that 49.9% of carbon yield on the average. It means that half of the total carbon inside raw material will be emitted to the air or stored in the form of half-carbonized matter which is easily decomposed (volatile matter, explained later). To raise the carbon fixation potential, carbon yield must be improved. Charcoal is composed of (1) moisture, (2) ash content, (3) volatile matter and (4) fixed carbon. To raise carbon yield, not only charcoal yield, but also fixed carbon content must be higher. To calculate carbon yield, percentage of each component in charcoal was measured. Analyses of charcoal were conducted in Forest Product Technology Research and Development Center according to the process indicated in the SNI (Standard Nasional Indonesia). (1) Moisture content: Moisture content of charcoal immediately after finishing carbonization in the kiln was close to 0%. After unloading charcoal from the kiln, charcoal absorbs moisture from the air. In some cases of earth pit or other types of kilns, charcoal was watered after opening the kiln and moisture content of charcoal became higher. Moisture content of charcoal is calculated as follows:

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Weight of charcoal – Oven dried weight of charcoal Moisture content (%) = ――――――――――――――――――――――― x 100 Weight of charcoal

(2) Ash content: Some kinds of minerals derived from wood material (CaO, K2O, MgO, etc.) Ash content of charcoal is calculated as follows: Weight of ash in charcoal Ash content (%) = ――――――――――――――― x 100 Oven dried weight of charcoal

Formula indicated above is different from that of SNI. SNI uses (fresh) weight of charcoal as a denominator in the formula (it is the same for volatile matter content). For moisture content of charcoal can vary due to the time after unloading charcoal from kilns or moisture content of the air. Therefore, in this report, the above formula is applied for accurate comparison of charcoal quality among data from various sites. (3) Volatile matter: It comprises all those liquid and tarry residues not fully driven off in the process of carbonization. If the carbonization is prolonged and at a high temperature, then the content of volatiles is low. (FAO, 1987) Volatile matter content of charcoal is calculated as follows: Weight of volatile matter in charcoal Volatile matter content (%) = ―――――――――――――――― x 100 Oven dried weight of charcoal

(4) Fixed carbon = Pure carbon Fixed carbon content of charcoal is calculated as follows: Fixed carbon content (%) = 100 – Ash content – Volatile matter content

Formula indicated above is also different from that of SNI. In the case of SNI, Fixed carbon content (%) = 100 – Moisture content - Ash content – Volatile matter content. For the reason already mentioned above (for more accurate comparison), the above formula is used in this report. Pure carbon in charcoal is difficult to be decomposed. According to Seifritz (1993), it shows no chemical affinity to the oxygen of the air and it does not rot, neither in an aerobic nor in an anaerobic way. This component mainly contributes to carbon storage. (5) Charcoal yield and carbon yield Usually, efficiency of charcoal production is indicated by charcoal yield. Charcoal yield is calculated using formula mentioned below:

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Weight of charcoal (kg) Charcoal yield (%) =

―――――――――――――――――――――――

x 100

Oven dry weight of wood material (kg)

This indicator, however, cannot explain the efficiency of carbon fixation potential. Instead, ‘carbon yield’ is used in this paper. It expresses the percentage of pure carbon derived from wood material which is preserved in the produced charcoal. Carbon yield is calculated using formula mentioned below: Carbon yield (%) = Weight of charcoal (kg) Fixed carbon content (%) 100 - Moisture content (%) ――――――――――――――――― x ――――――――――― x ――――――――――― x 100 0.5 x Oven dry weight of wood material (kg) 100 100

The above formula indicates how many percent of carbon in wood material is stored in produced charcoal in the form of pure carbon. In this equation, it is presumed that carbon content of wood material is 50% as shown in Fig.3.

Fig.3 Carbon in wood material and pure carbon in charcoal

Data obtained from field survey in West Java and East Kalimantan were compared with other previous studies and effective charcoal production methods were determined. 4. Comparison of cost efficiency Not only production costs per ton charcoal, but also per ton carbon were calculated and compared. Costs of charcoal production by the kilns which were tried by this project were analyzed in this report. Transportation costs were not included. Costs for collecting wood material were analyzed in the next chapter. Costs per ton carbon were converted to US dollars. The exchange rate applied in this report is 1US$=Rp.8,610 (in 14, April 2004).

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5. Estimation of carbon fixation potential by charcoal production Viability of carbonization projects in several conditions mentioned below was examined: (1) Wood material after slashing shrubs or secondary forests is carbonized. (2) Wood residues after logging Acacia mangium plantations are carbonized. (3) Carbonizing slabs and sawdust at sawmill. For the estimation of carbon fixation potential, the amount of wood residues must be estimated. Amount of wood material obtained from shrubs, secondary forests in the three sites in West Java, and total amount of charcoal and carbon produced were estimated using field data. For Acacia mangium, data from West Java (RPH Maribaya and Tenjo, BKPH Parungpanjang, KPH Bogor, Perhutai Unit III) were compared with that from PT. MHP, South Sumatra. The amount of sawdust residue was estimated from field survey, statistical data and previous literatures.

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III. Types of kilns for field trials 1. Nonpermanent kiln 1-a. Earth pit kiln This type of charcoal production is very common in West Java. It is called “Cara timbun” in Indonesian language and “Fuseyaki” in Japanese (earth mound kiln is also called by these terms). Some of village residents were very skilled makers and using only materials obtained in the filed (for example, wood, bamboo, soil, grasses and leaves) (Photo 4). Wood materials piled up in the earth pit are covered by leaves, grasses and soil. Working process of earth pit kiln was shown in Photo 5 to 13. Sites with slope facing windward are usually chosen to build kilns.

Photo 4 Earth pit kiln in Ngasuh. After logging Pinus merkusii plantation of PT. Perhutani, some part of wood residue (wood of less than 10cm in diameter or wood with scars by taking resin) was given to local people. Local people produce charcoal from the material.

Photo 5 Digging earth pit (Maribaya)

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Photo 6 Wood materials were piled up in the pit. A gentle slope was made for more smooth ventilation. (Maribaya)

Photo 7 Local people prefer smaller sized kiln. (Maribaya)

Photo 8 Wood material was covered by leaves. Later, this was covered by soil. (Maribaya)

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Photo 9 Kiln is covered by soil. Kiln wall is made by bamboo. (Maribaya)

Photo 10 Checking the smoke coming out from the rear part of the kiln (Maribaya)

Photo 11 Smoke exits from the chink of rear wall made by wood. ( Ngasuh)

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Photo 12 Carbonization was finished. (Ngasuh)

Photo 13 Collecting fragmented charcoal. (Ngasuh)

Photo 14 Earth pit kiln at sawmill. The kilns is covered by soil and sawdust. From the front side of the kiln, charcoal had been already collected and stored in sacks (karung).

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At a sawmill near Jasinga town (located between Maribaya and Ngasuh experimental site, see Fig.1), one charcoal maker produce charcoal using wood residues from sawmill by the earth pit kiln method (Photo 14). Although, around Jasinga town, there are many sawmills, only one sawmill producing charcoal could be found.

1-b. Modified earth pit kiln: Brick floor and galvanized iron sheet for closing kiln In the trial of earth pit kiln at Forest Products Technology Research and Development Center, some amount of wood material was not fully carbonized. From the fear of producing low quality of charcoal and to reduce half-raw charcoal and increase the carbon yield, some modification has been made. For example, kiln’s floor was covered by bricks to reduce effects of soil moisture (Photo 15 and 18). Chimney was installed for more smooth ventilation (Photo 15). In some trials, galvanized iron sheets were used to cover the top of kilns following the method of “Fuseyaki” in Japan (Photo 17). Field trials were conducted in Forest Products Technology Research and Development Center and three locations (Maribaya, Ngasuh and Cianten) in West Java.

Photo 15 Covering kiln floor with bricks Arrangement of bricks was similar with that of flat kiln. (Bogor, Forest Products Technology Research and Development Center)

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Photo 16 Two lines of flues which connect with chimney were made. (Forest Products Technology Research and Development Center)

Photo 17 The kiln was covered with galvanized iron sheets. (Bogor)

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Photo 18 Brick floor trial in Cianten. At the rear part of the kiln, space for chimney was made.

1-c. Sawdust mound kiln This types of kiln is already applied at sawmills in Malaysia (Photo 19 and 20). At large scale sawmills, heavy machinery can be used to carry and piling up wood materials (Photo 21). For the fire often goes up and sawdust can be burnt, charcoal production by this kiln needs vigilance.

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Photo 19 and 20 Sawdust mound kiln in a sawmill in Malaysia Width:7m, Length:20m, Height:2m Wood material: 50m3, Sawdust: 13m3 (Information from Mr. Furumoto, Hyonen Kogyo. Co. Ltd.)

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Photo 21 Heavy machinery can be used to carry wood residues at large scale sawmills. (Malaysia)

Following the guidance by Mr. Furumoto, Hyonen Kyogo Co. Ltd., sawdust mound kiln was built in Ngasuh, Shorea experimental site. Photo 22 to 27 show working process for the kiln. This type of kiln can produce larger amount of charcoal at once. The carbonization process, however, must be watched overnight for the fear of exiting fire from sawdust.

Photo 22 Start loading wood material for sawdust mound kiln. Three poles are located vertically to secure the insufflations. (Ngasuh)

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Photo 23 Loading wood material was finished. (Ngasuh)

Photo 24 Covering kiln with sawdust. (Ngasuh)

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Photo 25 The rear part of the kiln. Slabs from a sawmill were utilized for the kiln wall. (Ngasuh)

Photo 26 Kiln volume reached 10m3. (Ngasuh)

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Photo 27 Ignition (in Ngasuh)

2. Movable kiln 2-a. Single drum kiln: Air inlets at the side of drum A drum kiln comprises a recycled oil drum with a chimney made of galvanized iron. This method is common in Indonesia and often used for carbonizing coconut shell. Around sites for field trial in West Java, however, utilization of this kiln could not be observed. Although the amount of charcoal produced at once is limited because of kiln size, it needs only 1 day for carbonization and can be used at least 100 times according to Okimori et al. (2003). Data obtained from field trials (conducted in October 2001) in Ngasuh and Cianten were recorded and compared. Drum kiln was used also in Maribaya (Photo 28), but no measurement was conducted.

Photo 28 Drum kiln (Maribaya)

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Air inlets are located at the side of kiln. Chimney and cover of the kiln can be detached (Photo 30). Burned fuel wood (starter) is put into the kiln from the top. At first air inlets near the bottom of kiln are opened. After finishing carbonization at the bottom zone of kiln, the air inlets are closed and the above inlets are opened. This is to equalize the quality of charcoal. 2-b. Single drum kiln: Air inlets at the bottom of drum If air inlets are located at the side of kiln, charcoal makers must carefully watch the kiln during the whole carbonization process. For easier control and possibility to reduce workforce for charcoal production, the air inlets were moved to the bottom (Photo 29 to 31). Once ignited from the bottom of the kiln (Photo 31), charcoal makers only watches the color of the smoke from the chimney. As same as the other types of kiln, if smoke color turns into thin blue, bricks under the kiln (Photo 31) are removed and the side bottom are closed by soil. Field trials were conducted in Ngasuh and Cianten in July 2002.

Photo 29 Experiment in Cianten. Air inlets at the side of kiln were closed. Instead, holes were made at the bottom of the kiln.

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Photo 30 Wood material was put from the top of the kiln. At the center of the kiln, one larger sized wood are located as shown in the Photo. After filling the kiln with wood material, this wood was pulled out. (in Cianten)

Photo 31 Fuel wood for starter is under the kiln. Ignited from the bottom of the kiln. (Toho experimental site of Yayasan Dian Tama, West Kalimantan)

2-c. Double drum kiln In Forest Products Technology Research and Development Center in Bogor, double drum kiln was tried once. Two oil drums were cut and opened and reconnected. The trial was conducted in June 2001.

3. Permanent kiln: Yoshimura kiln For the comparison with nonpermanent and movable kiln, trials of permanent kiln were conducted in Toho experimental site of Yayasan Dian Tama, West Kalimantan. This kiln was named after a Japanese charcoal maker who introduced this kiln to Yayasan Dian Tama. Although there were four Yoshimura kilns before the corporation with this project, before starting trials, some repairing was needed (Photo 32). Photo 33 to 37 show 24

working process of charcoal production. As shown in Fig. 4, firing port of this kiln is separated from main body of the kiln. This is to avoid burning of wood material and maintain the good shape of produced charcoal. This type of kiln needs larger amount of fuel wood for starter. As seen in Photo 33, evenly sized wood material was utilized. Wood material was put into the kiln vertically. Trial using smaller and not-evenly sized material was not conducted. In the trials, some part of wood material became ash (Photo 37). Wood vinegar was collected using bamboo (Photo 38).

Photo 32 Repairing kiln floor

Photo 33 Loading wood material

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Fig. 4 Kiln profile Firing port is separated from space for wood material. This is to produce good-shaped charcoal.

Photo 34 Wood material was covered by leaves of tree and palm

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Photo 35 After closing kiln by iron cover, kiln top was covered with soil.

Photo 36 Ignition. Larger amount of fuel wood for starter is needed.

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Photo 37 Carbonization was finished.

Photo 38 Collecting wood vinegar using bamboo

4. Kiln for producing sawdust charcoal: flat kiln A flat kiln is a modified type of earth pit kiln with brick on the floor and sidewalls. Usually, it is used for producing materials of activated carbon, briquette charcoal and so on. Sawdust and tree bark can be carbonized using this kiln. In large-scale activated charcoal factories, many kilns are combined and flues are connected to a single large-sized chimney (Photo 39 and 40). In Forest Products Technology Research and Development Center, a small sized flat kiln was constructed (Photo 41). Fig. 5 shows the size and profile of the kiln. Process of kiln construction and carbonization are explained in another report (Gustan Pari, et al. 2004).

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Photo 39 Flat kiln in an activated charcoal factory Kiln volume is about 7.7m3. Length of the kiln reachs 7m. (Parungpanjang town , West Java)

Chimney

Photo 40 Flues under the kilns are connected to one large sized chimney. (Parungpanjang, West Java)

Because the kiln does not have a roof, carbonization temperature is low (250 to 300 degrees Celsius) according to Mr. Sugai, Director of Hokuetsu Shoji Co. Ltd. (Personal communication). The air enters into the kiln through an interstice of sawdust particles, goes to the kiln floor and finally it exits from the chimney. Carbonization starts at the bottom of the kiln, and proceeds to the top of the kiln (surface of sawdust). The speed of carbonization depends on the size of sawdust particles and intensity of the air suction in the chimney (according to Mr. Sugai, Personal communication). Carbonization tests were conducted three times at Forest Product Technology Research and Development Center in September 2002 and June 2003. After finishing 2nd trial, the location of the chimney was changed to improve its ventilation.

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Photo 41 Flat kiln (Forest Product Technology Research and Development Center) In the 3rd trial. Raw material (sawdust brought from sawmill) was prepared beside the kiln.

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Fig. 5 Size of flat kiln constructed in Forest Products Technology Research and Development Center

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IV. Comparison of carbonization efficiency 1. Nonpermanent kilns Lists of data obtained from field trials are indicated in Table 1. For not all trials, fresh weight of wood material was not measured. In such case, dry weight of wood material was estimated from kiln volume. Table 2 and 3 are additional data for the estimation. Table 4 is the summary of those data indicated in Table 1. Several facts were found: (1) Using brick floor improved the quality of charcoal (higher fixed carbon content) and decrease half-carbonized material. The amount of ash (separated from charcoal for analyses), however, increased and charcoal yield decreased. For these reasons, carbon yield decreased. (2) Using galvanized iron sheet to cover the kiln increased the quality of charcoal. For the same reasons with brick floor kilns, however, carbon yield decreased. (3) In the case of sawdust mound, carbon yield was still low. It was partly because local people in West Java were still not used to large-sized kiln. Workers should be trained to maintain higher efficiency for large sized kiln. Sawdust mound kiln must be watched overnight for the fear of forest fire. This method is usually applied in sawmills for carbonizing wood residue. It is recommended that this sawdust mound is conducted in or around sawmills. (4) It became clear that earth pit could produce relatively higher quality of charcoal. (5) Skill of workers seems to affect quality of charcoal and carbon yield. At Cianten, where only one person had experience of charcoal making, carbonization efficiency was lower. Fig. 6 shows relationship between kiln volume and carbon yield. To increase the amount of charcoal produced at once and increase the yield and quality of charcoal, larger sized kilns were tried. Charcoal makers in the experimental sites, however, were not familiar with large size kilns and the results were, as shown in the Figure, that the larger was the size of kiln, the lower was the carbon yield.

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33

4)

3)

2)

1)

2)

Bogor Bogor Bogor Maribaya Maribaya Maribaya Maribaya Ngasuh Ngasuh Ngasuh Ngasuh Ngasuh Maribaya Ngasuh Ngasuh Ngasuh Cianten Cianten Cianten Maribaya Ngasuh Bogor Bogor Ngasuh

Location

5.45 7.77 4.42 2.82 4.17 6.81 5.41 5.00 2.41 2.26 3.81 6.40 4.26 4.48 11.13 7.37 8.09 17.62 4.39 7.18 8.48 20.55 34.19 4.33

2.36 1.55 2.69 3.71 2.62 2.28 1.87 3.05 1.63 2.31 1.65 2.59 1.51 1.80 2.02 1.64 1.86 1.83 2.24 2.85 5.02 4.18 1.77 2.00

Moisture Ash content content (%) (%)

15.45 9.56 16.71 19.51 19.80 17.82 20.23 9.57 20.54 20.60 21.10 20.46 17.28 17.84 11.95 12.92 23.85 19.61 11.79 11.79 10.45 12.38 13.01 19.02

Volatile matter content (%)

82.19 88.90 80.61 76.78 77.59 79.91 77.89 87.38 77.82 77.09 77.25 76.95 81.21 80.36 86.02 85.44 74.29 78.55 85.97 85.36 84.53 83.45 85.22 78.98

Fixed carbon content (%)

Charcoal analysis

n.a. n.a. n.a. 8.99 8.90 8.88 8.83 9.02 8.19 8.98 8.45 9.26 9.30 8.40 n.a. n.a. 8.64 8.95 9.30 n.a. 9.11 n.a. 9.43 9.08

pH

6 6 9 9 9 9 9 9 9 6 9 9 9 9 9 5 9 9 9 7 6 9 9 9

n.a. n.a. n.a. 9.24 3.91 3.52 4.40 2.76 3.00 2.63 3.00 2.40 3.84 2.76 2.76 2.76 4.08 8.63 2.63 3.60 4.20 n.a. 2.25 10.00

Raw mater

522.03 522.03 522.03 522.03 390.28 390.28 390.28 390.28 390.28 522.03 390.28 390.28 390.28 415.40 415.40 522.03

390.28

66.07

66.07

1992.6 664.6 1096.5

1190

700 1000 993

Fresh Wood weight of density wood 3 3) (kg/m ) material (kg)

66.07 66.07 66.07 66.07 66.07 66.07 66.07 66.07 66.07 66.07 66.07 66.07 66.07 66.07 66.07

Number of Kiln volume Volume of raw material samples for (m3) / Volume of charcoal analysis kiln (%) 3)

GIS- Galvanized iron sheet on the top of the kiln. Brick floor + GIS - Galvanized iron sheet on the top and bricks on the floor. Bogor - Forest Products Technology Research and Developent Center Refer to Table 2 and 3. Figures in parentheses : carbonization time excluding time for cooling down.

Earth pit Earth pit Earth pit Earth pit Earth pit Earth pit Earth pit Earth pit Earth pit Earth pit Earth pit Earth pit Brick floor Brick floor Brick floor Brick floor Brick floor Brick floor Brick floor GIS GIS Brick floor + GIS Brick florr + GIS Sawdust mound

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Notes:

Type of kiln

Kiln No.

1)

Table 1 Data list of nonpermanent kiln (Trials in West Java)

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M M M E E E E E E E E E E E E E E E M E M M M E

43.50 24.14 48.01

45.50

17.01 14.22 38.84

580.9 857.8 607.3 3186.9 1348.6 1214.1 1517.6 711.7 773.6 676.9 773.6 618.9 1324.4 711.7 711.7 711.7 1119.8 2367.2 648.5 1241.7 1125.8 504.2 570.0 2578.6

104.0 165.2 102.5 398.0 259.0 202.5 350.0 175.0 199.8 183.6 180.0 118.0 168.0 159.5 162.5 175.0 135.0 198.0 76.0 73.0 89.7 120.0 92.5 405.0

(Weight of raw Moisture Dry wight of Weight of material) content of wood charcoal M:Measured raw material material (kg) (kg) E:Estimated (%)

rial

17.90 19.26 16.88 12.49 19.21 16.68 23.06 24.59 25.83 27.12 23.27 19.07 12.68 22.41 22.83 24.59 12.06 8.36 11.72 5.88 7.97 23.80 16.23 15.71

Charcoal yield (%)

27.72 31.35 25.89 18.62 28.47 24.69 33.85 40.68 39.21 40.85 34.53 27.20 19.68 34.33 33.13 38.67 16.23 9.47 19.22 9.25 12.19 28.13 11.14 23.66

5 3 10 9 10 7 n.a. (2) (2) (3) (3) (2) 5 (2) (2) (3) 4 4 5 n.a. n.a. n.a. 7 13

25 148 2.5

Temperature (degree Celsius)

Acacia mangium

Rubber

Acacia mangium(60%), Pinus merkusii(20%), Gmelina arborea(10%), Caliandra(10%)

Acaica mangium(60%), Pinus merkusii(20%), Albizia(20%)

Other information

Carbon yield Carbonization Uncarbonized (%) time (day) 4) material (kg)

Charcoal, carbon

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Kiln No.

Table 2 Calculation of volume of raw material / kiln volume Fresh weight of Moisture content Dry weight of Wood density Volume of Volume of raw wood material material/Kiln wood material of wood material wood material (kg/m3) 2) Volume (%) (kg) (%) (kg) (m3)

No. of kiln in Table 1

Location

Kiln volume (m3) a

b

c

d=b*(1-c/100)

e

21 19 n.a. 1) 23

Ngasuh Cianten Cianten Bogor

4.20 2.63 2.09 2.25

1992.60 1190.00 1193.50 1096.50

43.50 45.50 45.50 48.01

1125.76 648.50 650.41 570.02

390.28 415.40 415.40 412.48

Notes:

f=d/e

g=100*f/a

2.88 68.68 1.56 59.31 1.57 74.83 1.38 61.45 Average 66.07 % 3)

1)

This data is not included in Table 1 because no charcoal analysis was made. Refer to Table 3. 3) This figure is utilized in Table 1 for estimating volume of raw material. 2)

Table 3 Wood density in each experimental site + Acacia mangium (BKPH Parungpanjang, KPH Bogor) Wood density Number of Location, Diameter (DBH) 2), or stand Species 3 1) species samples age (kg/m ) Max=7.9cm Schima sp., Fagraea sp. etc. Maribaya average 522.03 20 Max=43.3cm, mostly under 20cm Maesopsis sp., Bellucia sp., Schima sp. etc. Ngasuh average 390.28 19 Max=38.2cm, mostly under 20cm Macaranga sp., Maesopsis sp., etc. Cianten average 415.40 20 3, 5 8 and 10 years old stand Acacia mangium 412.48 59 Notes: Data were obtained in forest area under jurisdiction of PT. Perhutani, Unit III, KPH Bogor. 1) Wood density = (oven dry stem weight) / (stem volume) 2) Data obtained from tree census conducted in shrubs and secodary forests adjacent to kiln sites.

Table 4 Comparison of carbon yield (Summary of nonpermanent kiln) Location

Bogor

Type of kiln

Earth pit Brick floor and GIS Maribaya Earth pit Brick floor GIS on the top Ngasuh Earth pit Brick floor Sawdust mound GIS on the top Cianten Brick floor All locations Earth pit Brick floor All

No. of samples

Fixed carbon content (%)

3 2 4 1 1 5 3 1 1 3 12 7 24

83.90 84.33 78.04 81.21 85.36 79.30 83.94 78.98 84.53 79.60 80.03 81.69 81.24

35

Charcoal yield Carbon yield (%) (%)

18.01 20.02 17.86 12.68 5.88 23.98 23.28 15.71 7.97 10.71 20.45 16.38 17.90

28.32 19.63 26.41 19.68 9.25 36.49 35.38 23.66 12.19 14.97 31.09 24.39 26.17

Fig. 6 Relationship between kiln volume and carbon yield

2. Movable kilns: drum kilns Table 5 is the list of data from field trials and analyses of charcoal quality. Single drum kilns were tried at Ngasuh and Cianten experimental sites. The reason of low charcoal and carbon yield was still not known clearly. One of the reasons can be skill of workers. Some technicians at the Forest Products Research and Development Center stated that higher moisture content in the air (altitude of Cianten experimental site is more than 900m and annual rainfall is above 4,000mm.) affected the yield. Carbonization efficiency was compared in each experimental site as shown in Table 6 and Fig. 7. It is apparent that there was no reverse effect of moving air inlets from the side to the bottom of drum. Drum kiln with air inlets at the bottom is easier to control and could reduce the number of workers to watch the carbonization process. Double drum kiln was tried once at the Forest Products Technology Research and Development Center. The result, however, was not good from the aspects of carbon yield and amount of produced charcoal.

36

Table 5 Data list of drum kiln Single drum kiln: Air inlets at the side Charcoal analysis No.

Location Moisture content (%)

1 Ngasuh 2 Ngasuh 3 Ngasuh 4 Ngasuh 5 Ngasuh 6 Ngasuh 7 Ngasuh 8 Ngasuh 9 Ngasuh 10 Ngasuh 11 Ngasuh 12 Ngasuh 13 Ngasuh 14 Ngasuh 15 Ngasuh 16 Cianten 17 Cianten 18 Cianten 19 Cianten 20 Cianten 21 Cianten 22 Cianten 23 Cianten Average

3.50 4.43 3.18 4.95 4.37 7.46 9.03 6.95 5.46 8.85 5.20 4.80 4.19 3.48 2.94 5.07 5.20 4.49 5.91 6.79 4.37 4.43 3.59 5.16

Ash Volatile Fixed content matter carbon (%) content (%) content (%)

3.04 2.30 2.40 2.08 3.07 2.81 1.64 3.55 1.41 2.37 1.09 2.28 1.60 2.76 1.90 1.37 2.13 3.21 4.01 3.61 3.76 1.33 1.55 2.40

11.56 12.43 11.59 11.67 12.16 11.27 11.40 11.62 11.34 11.84 11.89 11.05 11.67 10.82 10.52 6.43 7.62 9.72 8.55 8.41 7.56 9.29 10.88 10.49

Raw material pH

85.40 85.27 86.01 86.25 84.77 85.92 86.96 84.83 87.25 85.79 87.02 86.67 86.73 86.42 87.58 92.20 90.25 87.07 87.44 87.98 88.68 89.38 87.57 87.11

No. of Fresh weight of Dry weight of Moisture samples for raw material raw material content (%) analysis (kg) (kg)

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

38.00 39.00 37.00 40.00 40.00 40.00 40.00 40.00 40.00 40.00 40.00 40.00 40.00 40.00 40.00 34.70 52.00 46.00 49.20 48.00 49.20 50.00 49.20 42.27

21.06 21.06 21.06 21.06 21.06 23.73 21.06 21.06 21.06 21.06 21.06 21.06 21.06 21.06 21.06 27.59 19.30 26.48 27.19 24.11 24.11 24.11 19.34 22.21

30.00 30.79 29.21 31.58 31.58 30.51 31.58 31.58 31.58 31.58 31.58 31.58 31.58 31.58 31.58 25.12 41.96 33.82 35.82 36.43 37.34 37.94 39.68 32.87

Weight of charcoal (kg)

5.80 6.20 6.10 6.00 6.10 6.35 6.13 5.93 5.87 6.21 7.20 7.20 8.60 8.40 8.00 5.00 7.00 5.80 6.40 6.00 5.80 7.20 6.00 6.49

Single drum kiln: Air inlets at the bottom Charcoal analysis No.

Location Moisture content (%)

1 Ngasuh 2 Ngasuh 3 Ngasuh 4 Ngasuh 5 Ngasuh 6 Ngasuh 7 Ngasuh 8 Ngasuh 9 Ngasuh 10 Ngasuh 11 Ngasuh 12 Ngasuh 13 Cianten 14 Cianten 15 Cianten 16 Cianten 17 Cianten 18 Cianten 19 Cianten 20 Cianten 21 Cianten 22 Cianten 23 Cianten 24 Cianten Average

6.26 4.70 3.71 5.36 6.59 6.74 7.00 5.91 4.88 7.19 7.10 5.79 6.55 7.12 6.42 4.65 6.79 6.83 7.57 7.54 7.45 7.21 7.44 6.27 6.38

Ash Volatile Fixed content matter carbon (%) content (%) content (%)

2.22 2.42 2.21 2.86 2.39 2.24 2.94 2.70 2.45 3.32 3.08 2.47 5.63 2.01 3.63 3.75 2.23 1.89 2.59 2.98 3.12 3.13 2.78 3.20 2.84

11.42 13.58 13.65 11.12 13.38 12.12 12.53 10.31 11.80 11.19 10.14 10.35 14.06 11.03 12.54 20.82 10.23 11.04 8.73 10.57 9.50 10.86 11.31 10.88 11.80

86.36 84.00 84.14 86.03 84.23 85.64 84.53 86.99 85.76 85.49 86.78 87.18 80.30 86.96 83.83 75.43 87.54 87.07 88.68 86.46 87.39 86.01 85.90 85.92 85.36

pH

9.05 8.69 9.00 8.98 8.88 8.76 9.08 8.89 8.72 8.86 8.88 8.75 9.93 10.17 9.71 9.71 9.66 9.75 9.81 9.75 9.82 9.75 9.89 9.69 9.34

Raw material No. of Fresh weight of Dry weight of Moisture samples for raw material raw material content (%) analysis (kg) (kg)

6 6 6 6 6 6 6 6 6 6 6 6 3 3 3 3 3 3 3 3 3 3 3 3

50.00 50.00 50.00 57.50 50.00 50.00 45.00 50.00 50.00 48.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.02

28.94 28.69 34.92 29.69 28.69 34.92 28.94 28.69 34.92 28.94 28.69 34.92 22.73 28.66 28.09 22.73 28.66 28.09 22.73 28.66 28.09 22.73 28.66 28.09 28.70

35.53 35.66 32.54 40.43 35.66 32.54 31.98 35.66 32.54 34.11 35.66 32.54 38.63 35.67 35.96 38.63 35.67 35.96 38.63 35.67 35.96 38.63 35.67 35.96 35.66

Weight of charcoal (kg)

7.35 9.15 8.29 9.15 9.65 9.30 8.30 9.30 9.65 7.70 10.60 10.90 5.50 4.80 8.50 7.00 3.70 8.10 6.30 3.45 11.20 8.30 4.20 8.80 7.88

Double drum kiln Charcoal analysis No.

1

Location

Bogor

Moisture content (%)

8.63

Ash Volatile Fixed content matter carbon (%) content (%) content (%)

2.68

10.47

86.85

pH

9.07

37

Raw material No. of Fresh weight of Dry weight of Moisture samples for raw material raw material content (%) analysis (kg) (kg)

1

77.50

17.82

63.69

Weight of charcoal (kg)

10.50

Charcoal, carbon Charcoal yield (%)

Carbon yield (%)

19.34 20.14 20.89 19.00 19.32 20.82 19.41 18.78 18.59 19.67 22.80 22.80 27.24 26.60 25.34 19.90 16.68 17.15 17.87 16.47 15.53 18.97 15.12 19.93

31.87 32.83 34.79 31.16 31.32 33.10 30.71 29.65 30.67 30.76 37.62 37.63 45.27 44.38 43.07 34.84 28.55 28.52 29.40 27.02 26.35 32.42 25.53 32.93

Carbonization Temperatur time (hours) e (highest)

5.75 5.25 4.50 5.20 5.00 4.20 4.15 4.05 4.25 4.00 5.27 5.27 4.12 4.08 5.00 5.45 6.00 5.30 6.00 6.00 6.00 6.00 6.00

Date

2/October/2001 2/October/2001 2/October/2001 2/October/2001 2/October/2001 3/October/2001 3/October/2001 3/October/2001 3/October/2001 3/October/2001 4/October/2001 4/October/2001 4/October/2001 4/October/2001 4/October/2001 9/October/2001 9/October/2001 9/October/2001 10/October/2001 10/October/2001 10/October/2001 10/October/2001 10/October/2001

Charcoal, carbon Charcoal yield (%)

Carbon yield (%)

20.69 25.66 25.48 22.63 27.06 28.58 25.96 26.08 29.66 22.57 29.73 33.50 14.24 13.46 23.64 18.12 10.37 22.53 16.31 9.67 31.15 21.48 11.77 24.47 22.28

33.49 41.09 41.28 36.85 42.59 45.65 40.81 42.70 48.39 35.82 47.93 55.03 21.37 21.74 37.09 26.06 16.93 36.55 26.73 15.46 50.39 34.29 18.72 39.42 35.68

Carbonization Temperatur time (hours) e (highest)

6.05 6.14 4.20 6.14 4.16 4.30 4.29 4.30 4.58 3.18 4.35 3.40 4.50 6.15 4.75 4.10 7.20 5.00 4.45 8.20 6.70 5.55 7.10 5.25 5.17

605 580 590 580 600 685 630 685 680 680 665 600

Date

18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002 18/June/2002

Charcoal, carbon Charcoal yield (%)

Carbon yield (%)

16.49

26.17

Carbonization Temperatur time (hours) e (highest)

4.50

Date

29/June/2001

38

Table 6 Comparison of efficiency for carbonization (Summary of drum kiln) Location

No. of samples

Type of kiln

Ngasuh

Air inlets at the side Air inlets at the bottom Average Cianten Air inlets at the side Air inlets at the bottom Average Bogor Double drum Total average (exclude double drum)

15 12 27 8 12 20 1 47

Carbon yield (%)

Ngasuh: side 45 Ngasuh: bottom Cianten: side 40 Cianten: bottom 35 Bogor: double

Fixed carbon Charcoal yield (%) content (%) (fresh weight/dry (excluding moisture) weight)

86.19 85.59 85.93 88.82 85.12 86.60 86.85 86.21 15 12 8 12 1

21.38 26.47 23.64 17.21 18.10 17.75 16.49 21.13

86.19 85.59 88.82 85.12 86.85

21.38 26.47 17.21 18.10 16.49

30 25 20 15 10 5 0 Ngasuh: side Fig. 8

Ngasuh: bottom

Cianten: side Type of kiln

Cianten: bottom

Comparison of efficiency for carbonization (drum kiln)

39

Bogor: double

Carbon yield (%)

34.99 42.64 38.39 29.08 28.73 28.87 26.17 34.34 34.99 42.64 29.08 28.73 26.17

3. Permanent kiln: Yoshimura kiln Permanent kiln can produce larger amount of charcoal compared with nonpermanent kilns. This type of kiln requires large amount of fuel wood for starter because of the distance from firing port to main body of the kiln. For this reason, weight of starter cannot be neglected and included in the analysis. As shown in Table 7, in these trials, large amount of wood material became ash and carbon yield was about 33.4%. According to the Table, 5m3 kiln showed higher efficiency for carbonization. In the case of nonpermanent kiln, larger size of kiln is recommended also from the aspect of cost efficiency (explained later in the next chapter). 4. Flat kiln for sawdust charcoal Table 8 shows the results of trials using the flat kiln. Because of lower carbonization temperature, higher volatile matter content and lower fixed carbon content were observed. Because the staffs (technicians and hired labors) in Forest Product Technology Research and Development Center were not familiar with this method, charcoal yield was very low for the first trial. Charcoal yield was improved as the staffs got used to this techniques. Carbon yield could reach 24.2%. 5. Comparison of carbon yield To evaluate the data obtained by this project, the results from field trials in West Java and East Kalimantan were compared with previous researches as shown in Table 9. The following facts were found: (1) It is difficult to achieve 50% of carbon yield. Only two cases for single drum kiln (Single drum kiln, air outlets at the bottom, Table 5) showed more than 50% carbon yield. Most cases in Indonesia showed 20 to 40%. (2) In trials by the project, single drum kiln in Ngasuh experimental site and Yoshimura kiln showed the highest carbon yield (38.39% and 37.85%), although in the case of Yoshimura kiln, large amount of starter was necessary. (3) Average carbon yield of earth pit kiln was less than 30%. (4) For Mark V kiln (Photo 42), data in Thailand showed higher carbon yield (42.85%). On the other hand, data in Indonesia showed lower yield (25.21%). This can be partly explained by the high specific gravity of raw material in Thailand. Specific gravity of Acacia catechu is 0.98 according to Nettai Shokubutsu Yoran (in Japanese). Even considering this factor, yield of Indonesia was still low. (5) Permanent kilns (brick kilns) showed higher yield. It, however, sometimes can be lower according to several factors. More skilled workers are necessary for building kilns and producing charcoal. (See Photo 43 for brick kiln) (6) If raw material with higher specific gravity was carbonized, carbon yield became higher. As shown in the data by Tjutju et al. (2003), mangrove charcoal showed higher yield than Acacia charcoal. Data from Thailand also supported this fact. 40

41

Ash content (%)

Raw material

15.94 1.48 18.91 2.12 19.72 1.64 14.50 3.86 17.27 2.27 17.42946048 1.7956785

Volatile matter content (%)

2684.00 2352.00 1243.00 1671.00 1987.50

41.82 42.77 30.42 31.65 36.67

1561.53 1345.99 864.93 1142.06 1228.63

Fresh weight Moisture content Dry wight of of wood of raw material wood material material (kg) (%) (kg)

4.94 3.86 5.40 5.63 4.96 4.4033333

Moisture content (%)

158.8 70.39 83.36 73.13 96.43

1st 2nd 3rd

Trials

3.39 3.86 2.46

Moisture content (%)

24.62 23.58 21.00

3.99 4.08 6.35

71.39 72.34 72.65

Volatile Fixed Ash content matter carbon (%) content (%) content (%) pH

8.63 8.80 7.37

Dry weight of starter (kg)

82.58 78.97 78.64 81.63 80.46 80.77486105

Fixed carbon content (%)

Charcoal analysis

Table 8 Results: flat kiln (sawdust charcoal) Charcoal analysis

1 2 3 4 Average

Kiln No.

1 2 3 4 Average

Kiln No.

Table 7 Results: Yoshimura kiln

2 6 6

11 11 11

Kiln volume (m3)

27.02 25.78 18.38 22.77 23.49

Charcoal yield (%)

5 5 3 3

Raw material

38.51 37.20 24.95 32.97 33.41

Carbon yield (%)

840.00 1848.00 1787.00

20.84 20.84 19.31

Other information

7 8 6 5 6

664.98 1462.95 1442.00

63 55 32 24 43.50

64.81 254.60 229.50

9.75 17.40 15.92

Charcoal yield (%)

18 14 7 14 13.25

13.44 24.21 22.56

Carbon yield (%)

Charcoal, carbon

5 6 4 4 4.75

Other information

Acaia mangium Heavea sp. (Rubber) Vitex sp. (Laban) Bellucia sp.

Tree species for raw material

36 60 72

160 48 192

Carbonizatio Halfn time carbonized (hours) material (kg)

Carbonization Weight of Carbonization time Weight of wood time (day) (excluding ash (kg) vinegar (kg) cooling down)

Moisture Dry wight of Weight of Fresh weight wood content of charcoal of wood raw material material (kg) material (kg) (kg) (%)

24.53 24.50 16.77 21.40 21.80

Charcoal yield (include starter) (%)

Charcoal, carbon

3 3 3 3

Number of Kiln volume (m3) samples for charcoal analysis

Number of samples for charcoal analysis

422 347 159 260 297

Weight of charcoal (kg)

8.63 9.47 8.47 8.74 8.83 77.21807467

pH

42

Type of kiln

2 1 1 2 2 3 3

5.0 5.5

11.0

11.64 10.50 19.51 22.27 22.27

19.02 19.06

17.61 9.29 25.03 22.99

Volatile matter

85.93 86.60 77.32 75.05 73.24

80.03 87.64 68.16 73.36 90* 78.98 77.69

Fixed carbon content (%)

3.23

4.81

Acacia mangium, Rubber Eucalyptus, etc. Secondary forest species (Alstonia, Arocarpus, etc.) Mangrove Acacia mangium Acacia catechu, etc.

Paraserianthes, Maesopsis, etc.

13 Yoshimura kiln 14 Brick kiln 15 16 17 18 Brick Beehive kiln

19 Flat kiln (sawdust)

23.07

182.97

192.25 111.5 976.30

384.50 458.5

452.30

7.76 6.45 20.4

405.00 50.60

52.90

203.13

Amount of charcoal produced (kg)

14.35

26.40 30.00 23.42 26.95 20.97 39.60

23.64 17.75 24.2 17.92 30.40

20.45 14.00 16.00 31.10 14.3* 15.71 32.80

Charcoal yield (%)

20.07

37.85 43.18 34.83 46.28 29.65 47.87

38.39 28.87 35.22 25.21 42.85

31.09 23.11 20.22 42.45 32.00 23.66 48.08

2

10 9 4

10 5

1 1 1 10

13 1

5-10 3 2-8 0.5

Carbon yield Carbonizatio (%) n time (days)

Bogor, West Java, Indonesia

Thailand

Toho, West Kalimantan, Indonesia Bogor, West Java, Indonesia Teluk Dalam, East Kalimantan, Indonesia

Ngasuh, West Java, Indonesia Cianten, West Java, Indoensia Thailand Teluk Dalam, East Kalimantan, Indonesia Thailand

Ngasuh, West Java, Indonesia Thailand

The project Sudradjat and Salim (1994) Agus (1982) Tjutju et al. (2003) Tjutju et al. (2003) Royal Thai Government and US. Agency for International Development (1984)

The project The project Royal Thai Government and US. Agency for International Development (1984) Agus (1982) Royal Thai Government and US. Agency for International Development (1984)

The projet

Location

West Java, Indonesia Purwosari, Gunung Kidul, Yogyakarta, Indonesia Yogyakarta, Indonesia Thailand

The project Sri Nugroho, et al. (2004) Sri Nugroho, et al. (2004) Royal Thai Government and US. Agency for International Development (1984) Coomes and Burt (2001) in Glaser et al. (2002) The project Royal Thai Government and US. Agency for International Development (1984)

Literature

72.13

4.40 1.80 17.43 80.77 3.75-4.21 1.70-4.90 7.50-27.2 69.20-80.70 6.37 2.61 20.97 79.42 2.37 3.79 8.075 87.965 7.39 1.42 22.22 76.335 19.29 74.88

2.43 2.90 3.17 2.34 3.80

2.00 3.25

2.36 3.07 4.14 3.65

Secondary forest species Teak, Acacia mangium Dalbergia latifolia, teak, Acacia mangium, Mahogany Acacia catechu, etc. Secondary forest, fruit orchard Secondary forest species Acacia catechu, etc.

Wood material

2.0 2.0 8.3

4.8

5.56 6.08 5.87 6.25 3.77

4.33 5.66

4.73 5.83 7.29 6.96

Moisture Ash content content (%)

Secondary forest species Secondary forest species Acacia catechu, etc. Secondary forest species (Alstonia, Arocarpus, etc.) Acacia catechu, etc.

Sawdust mound kiln

Earth mound kiln

Earth pit kiln

Type of kiln

27 20 7 1 2

0.2 0.2 0.2

10.0 0.7

12 2 4 5 98 1 5

No. of samples

2.4-9.2 2.0 2.0-3.0 0.7

Size of kiln (m3)

8 Single drum kiln 9 10 11 Mark V kiln 12

1 2 3 4 5 6 7

No.

Continue

Nonpermanent kiln 1 Earth pit kiln 2 3 Earth mound kiln 4 5 6 Sawdust mound kiln 7 Movable kiln 8 Single drum kiln 9 10 11 Mark V kiln 12 Permanent kiln 13 Yoshimura kiln 14 Brick kiln 15 16 17 18 Brick Beehive kiln Kiln for sawdust charcoal 19 Flat kiln

No.

Table 9 Comparison: Carbon yield and other information

Mangrove wood, however, is getting more difficult to obtain at the present. (7) Carbon yield of flat kiln was still lower comparing with other types of kilns. From these data, drum kiln or permanent kilns can be recommended if considering the efficiency of carbonization. drum kiln, however, can produce small amount of charcoal at once. Permanent kilns need skilled worker and higher costs for building kilns, and are less suitable for carbonizing small sized wood residues. It needs evenly sized wood material. Earth pit kiln still can maintain more than 30% carbon yield if charcoal makers were well-trained.

Photo 42 Mark V kiln (East Kalimantan) Photo by Agus (1982) Behind the kiln: Retort kiln.

Photo 43 Brick kiln in East Kalimantan Photo by Agus (1982)

43

V. Comparison of cost efficiency 1. Earth pit kiln and brick floor kiln Table 10 shows the cost to produce charcoal by earth pit kiln (kiln volume = 4.5m ). Earth pit kiln merely uses materials which are available in the field, and only labor cost was considered here. Totally, Rp.70,000 is necessary if one worker make one kiln. In the case of smaller kiln, digging earth pit and loading wood material can finish in one day and total costs can be reduced to Rp.60,000. Fig. 8 shows the relationship between kiln volume (volume of wood material) and weight of produced charcoal. As already indicated in Fig. 6, efficiency of carbonization of larger sized kiln (more than 8m3) declined drastically and in this figure, such kiln was excluded. Estimation using the equation in the figure indicates that 3m3 kiln can produce 189kg charcoal and 4m3 kiln can produce 284kg charcoal. 3

Table 10 Costs for charcoal production by earth pit kiln Item Digging earth pit Loading wood material Watching kiln (ignition to closing kiln) Unloading charcoal Total

Amount 1 person*day 4.5m3

Price (Rp.) 15,000 15,000

2 days

30,000

1 person*0.5day

10,000 70,000

Fig. 8 Relationship between kiln volume and weight of produced charcoal Note: Earth pit kiln at Maribaya and Ngasuh. Large sized kiln (9.24m3) at Maribaya was excluded.

44

Table 11 demonstrates one example of working schedule. Considering period of cooling process, one worker can make two kilns. This schedule was made under the assumption that whole carbonization process (including cooling down) can finish in one week (7 days). In this case, first charcoal can be obtained in 9th day. After that, every 4 days charcoal can be unloaded (Table 12). Table 12 is the cost estimation under this condition. For one month (29 days), one worker can produce 1.70 ton charcoal and 1.28 ton of The costs were Rp.255,282(US$29.65)/t-Charcoal and carbon. Rp.338,929(US$39.36)/t-Carbon. After about 2 months (61 days), 4.00ton charcoal and 2.99ton carbon can be produced at the cost of Rp.230,131(US$26.73)/t and Rp.305,537(US$35.49)/t respectively.

Table 11 One example of working schedule for one worker (Earth pit kiln) Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

1st kiln Digging pit Loading wood material, Ignition Watching Watching Watching, Closing kiln

2nd kiln

Digging pit Digging pit, Loading wood material Loading wood material, Ignition Watching Watching Watching, Closing kiln

Unloading charcoal Loading wood material, Ignition Watching Watching Watching, Closing kiln

Unloading charcoal Loading wood material, Ignition Watching Watching Watching, Closing kiln

Unloading charcoal

45

Table 12 Calculation of cost per charcoal and carbon (one worker) Accumulated amount

Average cost (Rp.)

Charcoal production (unloading)

Days

Total wage (Rp.)

Charcoal (kg) 1)

Carbon (kg) 2)

Cost/t-Charcoal

Cost/t-Carbon

1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 14th

9 13 17 21 25 29 33 37 41 45 61

135,000 195,000 255,000 315,000 375,000 435,000 495,000 555,000 615,000 675,000 915,000

284 568 852 1136 1420 1704 1988 2272 2556 2840 3976

213.91 427.82 641.73 855.64 1069.54 1283.45 1497.36 1711.27 1925.18 2139.09 2994.72

475,352 343,310 299,296 277,289 264,085 255,282 248,994 244,278 240,610 237,676 230,131

631,110 455,802 397,366 368,148 350,617 338,929 330,581 324,320 319,451 315,555 305,537

Notes: 1) One worker make 2 kilns (Size = 4m3) following the schedule indicated in Table 12. The kiln can produce 284kg charcoal at once. 2) Percentage of pure carbon in charcoal (fresh weight) = 75.32% (Calculated from the data shown in Table 1. Average of earth pit kiln at Maribaya and Ngasuh).

Table 13 Costs for producing charcoal and carbon (per one worker, earth pit kiln) under different assumptions Labor wage

Duration

Wage =Rp.20,000/person*day Wage =Rp.25,000/person*day

29 days 61 days 29 days 61 days

Accumulated amount Charcoal Carbon (kg) (kg)

1,704 3,986 1,704 3,986

1,238 2,995 1,238 2,995

Average cost (Rp.) Cost per Cost per charcoal carbon

340,736 306,841 425,469 383,551

451,906 407,383 564,882 509,229

Table 13 demonstrates average costs under different assumptions (different labor wage). Outside Java Island, labor costs are higher and Rp.15,000/person*day is not applicable. If wage is Rp.25,000/person*day, cost per ton carbon is Rp.509,229 (US$59.14) after 2 months’ operation. One of other alternatives is buying produced charcoal from local people. During 2001 to 2002, local price of charcoal was Rp.5,000 (Sri Ngroho et al. (2004) stated that local price around Yogyakarta was also Rp.5,000). Average weight of charcoal per karung in Ngasuh was 10.64 kg (about this figure, explained later in Table 30). In such case, cost per ton carbon becomes Rp.617,104 (US$71.67). PT. Perhutani sells fuel wood of Acacia mangium (stem and branches less than 10m in diameter) at the price of Rp.17,000/staple meter (0.75m3). One informant from a local brick factory near Leuwiliang town (See Fig.1, located between Bogor and Jasinga 46

town) bought 1 staple meter of fuel wood at the price of Rp.20,000. If wood material must be bought, local people never produce charcoal. PT. Perhutani gives some part of fuel wood to local people for free and they can make charcoal without considering costs for material. Table 14 shows costs to produce charcoal by brick floor kiln (Rp.190,000, US$22.07). If carbonization efficiency is not improved using bricks, earth pit kiln is recommended because in the process of brick production, certain amount of carbon is emitted to the air. According to the data obtained by interview at brick factory (Photo 44) located near Leuwiliang town (See Fig. 1, located between Bogor and Jasinga town), to produce 20,000 bricks, 15 staple meter (1 staple meter = 0.75 m3) of fuel wood is necessary. Oven dry weight of fuel wood stored beside the kiln was 148.21 kg/1 staple meter. To produce 20,000 bricks, 1,110kg of carbon was emitted (0.0555kg/brick). Production of 400 bricks equals to 22.2kg carbon emission. Table 14 Costs for charcoal production by brick floor kiln Item Brick Digging pit and putting bricks Loading wood material Watching kiln (ignition to closing kiln) Unloading charcoal Total

Amount 400 1person*1day 1person*1day 1person*2day 1person*half day

Price (Rp.) 120,000 15,000 15,000 30,000 10,000 190,000

Photo 44 A kiln for producing bricks. Comparing with other factories around experimental sites in West Java, this kiln is larger size.

47

3. Earth pit kiln at sawmill At a sawmill near Jasinga town, slabs were carbonized by earth pit kiln (Photo 14). Table 15 is the result of survey conducted at the sawmill. This is only rough estimation based on data from interview. Actual data of charcoal yield (30.41%) and carbon yield (43.78%) could be lower than estimation in Table 16. One charcoal maker was working with 2 kilns. Carbonization finishes 10 days after ignition, and unloading of charcoal is taken place twice within 10 days. 300 karung of charcoal (produced in 10 days) are sold at the price of Rp.1,650,000 (US$191.64). After selling charcoal, owner of the sawmill took two thirds of the gains (Rp.1,100,000, US$127.76), and the charcoal maker took the rest (Rp.550,000, US$63.88). Monthly income of the charcoal makers can amount to Rp.1,650,000. Produced carbon amounts to 2.22t/10days. Regarding Rp.1,650,000 as production cost (if the charcoal is not sold and stored for carbon sequestration), average cost per ton carbon is Rp.247,748 (US$28.77).

Table 15 Information of earth pit kiln at a sawmill (one kiln) Kiln volume Dry weight of wood material (slab) Produced charcoal (kg) Charcoal yield Charcoal analysis Moisture content Fixed carbon content

Carbon yield Carbonization time (including cooling down) Price of charcoal

25.65 m3 5,070 kg 1) 1,542 kg 2) (10.28kg/karung x 150karung) 30.41 % 2.81 % 74.06 % 43.78 % 10 days Rp. 5,500/karung

Notes: 1) Sample of slabs (0.71m3) was weighed. Dry weight of the sample was 140.84kg. Using this data, total dry weight of wood material was estimated from kiln volume (140.84 kg x 15.65m3 / 0.71m3). 2) 5 karung of produced of charcoal were weighed. The average was 10.28kg/karung. The respondent (charcoal maker at the sawmill) stated that 150 karung of charcoal is produced

4. Drum kiln Table 16 shows costs for making single drum kiln. The cost was Rp.109,500/kiln (US$12.72).

48

Table 16 Costs for making single drum kiln Item Oil drum Galvanized iron sheet Rivet Worker Total

Amount 1 1.5 m 20 1person*day

Price (Rp.) 75,000 7,500 2,000 25,000 109,500

Drum kiln (air inlets at the bottom of kiln) can produce 7.88kg charcoal at once (Table 5). From the experience in the field, it is assumed that one worker was able to operate 5 drum kilns. According to Okimori et al. (2003), drum kilns can use at least 100 times. After 100 times carbonization, 5 drum kilns can produce 3.9t charcoal or 3.7t carbon (Table 17). Cost per ton-carbon was Rp.656,806(US$76.28)/t-Carbon. This estimation was made under the assumption that labor wage is Rp.15,000/person*day. Cost/10kg-charcoal was Rp.5,250, and this is about the same as local price of charcoal. Table 18 indicates cost per ton charcoal and carbon when labor wages are higher than the assumption of Table 17.

Table 17 Costs for producing charcoal and carbon (per one worker, 5 single drum kilns) Accumulated amount Day

1 2 3 4 5 10 30 60 100

Average cost

Cost (Rp.)

Charcoal (kg) 1)

Carbon (kg) 2)

Cost/t-Charcoal (Rp.)

Cost/t-Carbon (Rp.)

562,500 577,500 592,500 607,500 622,500 697,500 997,500 1,447,500 2,047,500

39 79 118 158 355 1,143 2,325 3,901

31 63 94 126 283 913 1,858 3,117

14,657,360 7,519,036 5,139,594 3,949,873 1,967,005 873,009 622,688 524,919

18,340,041 9,408,203 6,430,923 4,942,284 2,461,218 1,092,354 779,139 656,806

Notes: 1) One kiln can produce 7.88kg at once. 2) Percentage of pure carbon in charcoal (fresh weight) = 79.92% (Calculated from the data shown in Table 5).

49

Table 18 Costs for producing charcoal and carbon (per one worker, 5 single drum kilns) under different assumptions Wages

Cost (Rp.)

Produced charcoal (kg)

(1) Rp.30,000/person*day (2) Rp. 20,000/person*day

2,572,500

3,901

3,117

659,514

825,218

3,901

3,117

794,109

993,629

(1) Rp. 35,000/person*day 3,097,500 (2) Rp. 25,000/person*day Notes: (1) Wages for making drum kilns (2) Wages for producing charcoal

Carbon in charcoal (kg)

Cost/t-Charcoal (Rp.)

Cost/t-Carbon (Rp.)

Table 19 Costs for making double drum kiln Item Oil drum Galvanized iron sheet Rivet Worker Total

Amount 4 1m 30 1person*10day

Price (Rp.) 260,000 15,000 3,000 250,000 528,000

Costs for making double drum kiln are indicated in Table 19 (Rp.528,000, US$61.32). The total costs were nearly 5 times as much as those of single drum kiln. The amount of produced charcoal, however, was 10.5kg (Table 5). This method was not economically viable.

5. Yoshimura kiln Table 20 and 21 indicates costs for building Yoshimura kiln (5m3 and 3m3). The difference between 5m3 and 3m3 kilns was Rp.656,878. Table 22 shows the labor costs for producing charcoal. If two kilns are operated simultaneously, 2 workers can operate 2 kilns after ignition. Under the assumption made in Table 23, average cost per charcoal and carbon are calculated (Table 24). Even after carbonization is repeated 10 times (100 days), average cost per ton is still more than 3 million Rupiah (Rp.3,250,075/t-Carbon, US$377.48).

50

Table 20 Costs for building Yoshimura kiln (5m3) Item Bricks for kiln wall Bricks to uphold chimney Chimney Iron grating for kiln floor Roof of the kiln Transportation costs (grating and kiln cover) Cement Pole (8/8) for hovel Bar (9/9) for hovel Beam (5/7) Galvanized iron sheet Palm leaves Nail <Wages> Wages for workers

Quantity

Price per unit (Rp.)

Total (Rp.)

1,814

600/brick

1,088,400

600

600/brick

360,000

1

150,000/unit

150,000

4,91m2

100,000/ m2

490,874

2

5,15m

2

140,000/ m

721,552

1 trip

250,000/trip

250,000

2sacks

28,500/sack

57,000

9 9 26 39 sheets 150 sheets 1 packet

25,000 27,000 8,000 17,000/sheet 500/sheet 38,000/packet

225,000 243,000 208,000 663,000 75,000 38,000

3 workers (18 days)

20,000/person*day

1,080,000

Total

5,649,826

Table 21 Costs for building Yoshimura kiln (3m3) Item Bricks for kiln wall Bricks to uphold chimney Chimney Iron grating for kiln floor Roof of the kiln Transportation costs (grating and kiln cover) Cement Pole (8/8) for hovel Bar (9/9) for hovel Beam (5/7) Galvanized iron sheet Palm leaves Nail <Wages> Wages for workers

Quantity

Price per unit (Rp.)

Total (Rp.)

1,451

600/brick

870,600

600

600/brick

360,000

1

150,000/unit 2

150,000

2

314,159

3.28 m

2

140,000/m

459,189

1 trip

250,000/trip

250,000

2 sacks

28,500/sack

57,000

9 9 26 39 sheets 150 sheets 1 packet

25,000 27,000 8,000 17,000/sheet 500/sheet 38,000/packet

225,000 243,000 208,000 663,000 75,000 38,000 (3,912,948)

3 workers (18 days)

20,000/person*day

1,080,000

100,000/m

3.14 m

2

Total

4,992,948

51

Table 22 Costs for loading wood material and vigilance (watching) Trial Acacia (5m3) Hevea (5m3) Vitex (3m3) Bellucia (3m3)

For loading wood material Wages 6 workers x 3 days Rp.450,000 6 workers x 3 days Rp.450,000 4 workers x 3 days Rp.300,000 4 workers x 3 days Rp.300,000

Total wages Rp.650,000 Rp.700,000 Rp.500,000 Rp.450,000

Watching

Workers x days

Workers x days 2 workers x 4 days 2 workers x 5 days 2 workers x 4 days 2 workers x 3 days

Wages Rp.200,000 Rp.250,000 Rp.200,000 Rp.150,000

Note: Wages for labor = Rp.25,000/worker*day

Table 23 Assumptions for analysis (2 Yoshimura kilns: 5m3 x 2) Item Costs to build a kiln Wages for loading wood material Watching Unloading charcoal Carbonization time (including cooling down) Produced charcoal Percentage of carbon in (fresh weight of) charcoal

Amount 2 kilns, Rp.5,649,826/kiln 6 workers x 3 days, Rp.25,000/person*day 2 workers x 4 days 6 workers x 1 day

Price (Rp.) 11,299,652

7 days

-

769kg (429kg+347kg) 1)

-

77.22% 2)

-

450,000 200,000 150,000

Notes: 1) 2) Average of data from No.1 and No.2 in Table 7.

Table 24 Costs for producing charcoal and carbon (Yoshimura kiln) Accumulated amount Day

Average cost

Cost (Rp.)

Charcoal (kg)

Carbon (kg)

Cost/t-Charcoal (Rp.)

Cost/t-Carbon (Rp.)

10

12,099,652

769

594

-

-

20

12,899,652

1,538

1,188

8,387,290

10,861,551

30

13,699,652

2,307

1,781

5,938,297

7,690,103

40

14,499,652

3,076

2,375

4,713,801

6,104,378

50

15,299,652

3,845

2,969

3,979,103

5,152,944

100

19,299,652

7,690

5,938

2,509,708

3,250,075

6. Flat kiln Table 25 shows costs for building a flat kiln. Total cost was Rp.6,146,500 (US$713.88). As mentioned earlier, producing one piece of brick emits 0.0555kg carbon. This means that 222kg carbon was emitted by production of 4,000 pieces of bricks. 52

Emission factor for cement production in Japan was 417kgCO2/t (in the year of 2000, equivalent to 113.73kgC/t, 0.11373kgC/kg. Ministry of Environment). Using this figure, production of 15 sacks of cement (750kg cement) emitted 85.3kg carbon. Possibly, emission from cement production per kg in Indonesia is larger than that in Japan. Under the assumption indicated in Table 26, average costs for producing charcoal and carbon were calculated (Table 27). In this table, emission by brick and cement production is not included.

Table 25 Costs for building a flat kiln Item Galvanized iron sheet Scantling Nail Cement Sand Sieve (For sieving sand) Bricks Iron pipe for the chimney (Diameter: 6 inch)

Amount 34 sheet

Price (Rp.) 1,088,000 1,336,000 45,000 420,000 437,500 10,000 1,600,000

6kg 15 sacks 2.5m3 4,000

Wages of workers

6ｍ

625,000

Rp.35,0001) x 11 person*day + Rp.25,0002) x 8 person*day

585,000

Total

6,146,500

Note: The size and structure of the kiln is indicated in Fig.2. Costs for modification was not included. 1) Wages for skilled worker (3 workers) 2) Wages for non-skilled worker (2 workers)

Table 26 Assumptions for analysis Item Cost for building a kiln Carbonization time Charcoal produced at one time carbonization Percentage of carbon in (fresh weight of) charcoal Numbers of workers employed Wages of workers 1)

Amount Rp.6,146,500 3 days 0.255 t 69.55% 2 workers Rp.15,000/person*day

Data obtained in the 2nd trial (See Table 8)

According to Table 27, after 60days, 5.10ton charcoal and 3.55ton carbon are produced at the average cost of Rp.1,558,177(US$180.97)/t-Charcoal and 53

Rp.2,240,312(US$260.20)/t-Carbon respectively. If considering the carbon emission from brick and cement production mentioned earlier, the average cost per ton carbon becomes Rp.2,452,813 (US$284.88) (1.10% Increase). Table 28 shows cost estimation under the different assumptions. As mentioned earlier, Rp.15,000/person*day is too low in areas near large cities or outside Java Island.

Table 27 Costs for producing charcoal and carbon (Flat kiln) Accumulated amount Day

3 6 9 12 30 60

Average cost

Cost (Rp.)

Charcoal (kg)

Carbon (kg)

Cost/t-Charcoal (Rp.)

Cost/t-Carbon (Rp.)

6,236,500 6,326,500 6,416,500 6,506,500 7,046,500 7,946,500

255 510 765 1020 2550 5100

177 355 532 709 1774 3547

24,456,863 12,404,902 8,387,582 6,378,922 2,763,333 1,558,137

35,164,432 17,835,948 12,059,787 9,171,706 3,973,161 2,240,312

Table 28 Costs for producing charcoal and carbon under different assumptions (flat kiln) Labor wage

Duration

Wage =Rp.20,000/person*day Wage =Rp.25,000/person*day Wage = Rp.600,000/person*month 2)

30 days 60 days 30 days 60 days 30 days 60 days

Accumulated amount Charcoal Carbon (kg) (kg) 1)

2550 5100 2550 5100 2550 5100

1774 3547 1774 3547 1774 3547

Average cost (Rp.) Cost per Cost per charcoal carbon

2,880,980 1,675,784 2,998,627 1,793,431 2,874,534 1,669,338

4,142,315 2,409,467 4,311,470 2,578,622 4,141,278 2,404,978

Notes: 1) Emission by brick and cement production were not considered here. 2) Refer to Gustan Pari et al. (2004).

6. Comparison of costs for producing charcoal and carbon It is apparent that earth pit kiln can produce charcoal and carbon at the lowest costs. Considering carbonization efficiency, however, oil drum kiln still can utilized for carbon sequestration project. The average cost after 100 times carbonization was still Rp.656,000 (US$76.28; Costs for collecting wood material are not included.) and much lower than permanent kilns. This method can be recommended for small to middle scale charcoal production. In large scale production, many drums are utilized, and after 100 times carbonization, will be wastes. The drums should be utilized for other purposes to avoid environmental degradation.

54

Costs for earth pit kiln at sawmill was the lowest (US$28.77). It is because it can produce large amount of charcoal at once. It does not need to consider transportation cost of wood material as shown in the case of sawmill near Jasinga town. If the scale and carbon efficiency of charcoal production by earth pit (in the field), it can produce charcoal and carbon at lower price. The trials to enlarge kilns showed that it was difficult to maintain the same efficiency with small kiln because local people were not familiar with large kiln. There is, however, possibility that after many trials or trainings, local people can produce charcoal using large kilns at higher efficiency. Permanent kilns can produce larger amount of charcoal at once. The costs per produced carbon were much higher than those of earth pit and drum kiln. Permanent kilns need evenly sized material, and if materials with higher specific gravity are utilized as raw material, they can produce higher price of charcoal. Wood residues, however, are usually uneven sized, and it is difficult to obtain raw material with good quality (especially high specific gravity) recently.

55

VI. Evaluation of viability of charcoal production for CDM projects 1. Carbonization of wood material from shrubs or secondary forests 1-a. Total amount of charcoal and carbon produced in West Java experimental sties Table 29 shows total aboveground biomass in three locations. At Maribaya, some area had been burned for rice cultivation one year before the measurement and small trees and undergrowth dominated the area. Other than slash and burn, this area was utilized by local people as source of fuel and material for charcoal making. Fig. 9 shows aboveground biomass of fallow lands in East Kalimantan. Comparing with this figure, vegetation in Maribaya is equivalent to 1 year-old stand, Ngasuh is about 7 year-old stand and Cianten is about 4 to 5 year-old stand.

Table 29 Biomass amount of three locations in West Java Location

Total aboveground biomass (t/ha) 1)

Maribaya 2) Ngasuh Cianten

12.36 40.94 29.57

Wood material: Stems, branches and stumps of trees (t/ha) 5.24 (4.47) 36.62 25.28

Percentage (%) 42.39 (36.17) 89.45 85.49

Notes: 1) Average of 20 plots (size of plot = 10m x 10m) 2) Figures in parentheses indicate amount of wood material excluding branches.

Fig. 9 Aboveground biomass of fallow land (East Kalimantan) Data source: Kojima et al. (1997), Morikawa (2001) and data from this project (at Maribaya)

56

In Ngasuh and Cianten, no effects by slash and burn by local people. Larger sized trees had been often extracted for pulp, sawn wood, and other purposes. Photos 45 to 47 are vegetations at Maribaya, Ngasuh and Cianten.

Photo 45 Shrubs in Maribaya (in the year of 2001)

Photo 46 Secondary forest in Ngasuh (in the year of 2001)

57

Photo 47 Secondary forest in Cianten (in the year of 2001)

Table 30 shows total amount of produced charcoal in each location. Karung is Indonesian language which means large sized sack. Usually, charcoal is stored in karung and transported and sold. Weight of charcoal per karung seems to depend on wood density of materials indicated in Table 3. Amount of carbon stored in charcoal at three sites are indicated in Table 31. At Maribaya, wood material was collected from the whole slashed area. At other two sites, not all wood material was collected.

Table 30 Total amount of produced charcoal Location

Area (ha)

Maribaya Ngasuh Cianten

4.02 4.08 3.76

Total amount of produced charcoal (karung) 179 850 636

Weight of charcoal per karung (kg) 13.56 10.64 11.29

Number of samples1) 6 54 25

Total amount of produced charcoal (kg) 2,427.24 9,044.00 7,180.44

Note: 1) Number of karung with charcoal weighed and recorded.

Table 31 Amount of carbon stored in charcoal Location

Area (ha)

Maribaya 2)

4.02

Ngasuh Cianten

4.08 3.76

Amount of wood material (t/ha) 5.24 (4.47) 36.62 25.28

Amount of produced charcoal (total, t)

(t/ha)

2.43

0.60

9.04 7.18

2.22 1.91

Charcoal yield (%) 11.52 (13.51) 6.05 7.55

Amount of carbon stored in charcoal (t/ha) 1) 0.48 1.77 1.53

Notes: 1) Calculated under the assumption that percentage of carbon inside charcoal is 80%. 2) Figures in parentheses: amount of wood material excluding branches.

58

Percentage of carbon stored in charcoal 18.44 (21.61) 9.69 12.09

This low percentage of carbon storage in Maribaya is assumed to come from: (1) In Maribaya, small sized branches and twigs dominated the area (See Photo 45). (2) In the field, wood material was collected manually, and possibly, some materials were not collected and left on the ground. (3) Shrubs were cut not from the ground level. Stumps near the ground were still left in the field. These facts demonstrated that, in the field, because of several factors, it was difficult to utilized all wood residues and achieve high carbon yield. At the Ngasuh experimental site, if the wood material was fully carbonized, 3.66t/ha (Carbon yield = 20%) or 5.49t/ha (30%) of carbon can be produced. At the Cianten, the amount can be 2.53t/ha (Carbon yield = 20%) or 3.79t/ha (30%). Table 32 shows the cost for collecting wood material. Data was obtained from field trials in West Java. Wood material was collected all manually. No vehicle was used. After clear-cutting the shrubs or secondary forests, wood material was scattered in the area. The cost in Maribaya was higher than other site because of difficulty to find proper size of wood for charcoal production. In shrubs of Maribaya, small trees (diameter at breast height < 2cm) dominated the vegetation. In the case of Ngasuh and Cianten, costs for collecting wood material can be Rp.5,000 to Rp.6,250 per m3. Cianten is steep-slope area and the costs became higher than Ngasuh (slope is more gentle). Average of three sites shows that volume of material collected by one person*one day was 2.05m3. Cost to collect 1m3 was Rp.10,417 (US$1.20; under the rate in 14/4/2004. 1US$=Rp.8,610). If labor wage is Rp.20,000/person*day, the cost becomes Rp.13,889 (US$1.61 under the same exchange rate). When the wage is Rp.25,000/person*day, the cost is Rp.17,361 (US$2.02).

Table 32 Costs for collecting wood material Location

Maribaya Ngasuh Cianten

Distance

50 to 300 meter 50 to 300 meter 300 meter

Number of workers

Working hours

Volume of material collected (m3)

Wage (Rp./person *day)

Volume of material / person * day

Person*day / volume of material

Wage per volume (Rp./ m3)

4

8

3

15,000

0.75

1.33

20,000

2

8

6

15,000

3.00

0.33

5,000

2

5

3

15,000

2.40 1)

0.42 2)

6,250 3)

2.05

0.69

10,417

Average

Notes: 1) 2) 3) Recalculated: Working hours = 8 hours Æ Volume of material collected = 4.8 m3/2 workers.

Costs for collecting wood material can vary from place to place. In large scale plantation forests, trucks and other vehicles can be utilized for transportation. Even in such case, collecting wood material from the field to the road side is usually conducted

59

manually.

1-b. Carbonizing wood material from shrubs or secondary forests In the above case, several types and various sizes of kilns were utilized for charcoal production. One worker worked with one kiln and carbonization and cost efficiency became lower. Under the assumption indicated in Fig. 8, Table 11 and Table 32, cost per ton carbon is calculated (Table 33). In this table, it is assumed that not all wood material is utilized because of following reasons: (1) Some of stems and branches are left in the field to reduce soil erosion. (2) Small twigs (for example, less than 2cm diameter) are not suitable for charcoal production. (3) Some amount of wood could be utilized as fuel wood.

Table 33 Estimation of carbon fixation potential and the costs Amount of Location

wood material (t/ha) 1)

Ngasuh

Cianten

Volume of wood material (m3) 2)

Kiln volume (m3) 3)

Number of kiln

Produced charcoal (t/ha) 4)

Labor cost (Rp.) 6)

Weight of carbon in charcoal (t/ha) 5)

Charcoal production

Cost per ton

Collection of wood

carbon

material 7)

Rp. /t (US$/t)

36.62 (total) 18.31 (1/2)

46.92

71.01

17

4.92

3.71

1,170,000

355,040

24.41 (2/3)

62.55

94.68

23

6.79

5.11

1,530,000

473,387

12.64 (1/2)

30.43

46.05

11

3.32

2.50

810,000

287,843

16.85 (1/3)

40.57

61.41

15

4.39

3.31

1,050,000

383,791

411,178 (47.76) 391,906 (45.52)

25.28 (total)

Notes: 1) (Total)=Stem weight + Branch weight + Stump weight, (1/2)=half of total amount of wood material is utilized, (2/3)=two thirds of wood material is utilized. 2) Wood density=390.28kg/m3 in Ngasuh, 415.40kg/m3 in Cianten (Table 3). 3) Volume of wood material / Kiln volume =66.07% (Table 3). 4) 4m3 kiln can produce 284kg charcoal. In the last kiln, the volume becomes more than 4m3. Weight of produced charcoal was calculated using formula shown in Fig. 8. 5) Percentage of pure carbon in charcoal (fresh weight) =75.32% (Calculated from the data shown in Table 1) Average of earth pit kiln at Maribaya and Ngasuh. 6) 2 workers work with 4 kilns following the schedule shown in Table 11. Labor wage =Rp.15,000/person*day. 7) Data of Table 32 were used for the calculation.

According to the table, the costs were US$45 to 51/t-Carbon. If charcoal makers, however, are not trained well, weight of produced charcoal becomes lower. Specific 60

439,150 (51.00) 433,200 (50.31)

gravity of wood material also affects weight of produced charcoal. If specific gravity is low, the figures in Table 33 become lower. Labor cost was calculated under the assumption that labor wage is Rp.15,000/person*day. If the labor wage is Rp.25,000/person*day, the costs become as Table 34. As mentioned in the last chapter, if produced charcoal was bought at the price of Rp.5,000/karung, cost per ton carbon becomes Rp.617,104 (US$71.67). In such case, charcoal production must be watched carefully to prevent charcoal makers from taking wood material outside the boundary of project area.

Table 34 Cost per ton carbon: in the case that labor wage is Rp.25,000/person*day Location Ngasuh Cianten

1/2 2/3 1/2 2/3

Rp./t-Carbon 685,289 653,170 731,923 722,007

(US$) (79.59) (75.86) (85.01) (83.86)

In the case of drum kiln, total costs will be higher as indicated in the last chapter. To improve the cost efficiency, size of earth pit kiln must be enlarged without reducing charcoal yield. This, however, needs training because large-sized earth pit kiln is not common in Indonesia. Baselines can be as follows: (1) Slash-and-burn for agriculture (shifting cultivation) (2) Slash-and-burn for conversion of vegetation into tree plantations. If the baseline is slash-and-burn, assuming all carbon emitted to the air (actually, small amount of carbon still remains on the field in the form of charcoal in the case of shifting cultivation), total amount of sequestered carbon can be as shown in Table 33. In the densely populated area, there is competition with demand for fuel wood. In such case, leakage effects must be considered. For example, in Java Island, biomass from shrubs or secondary forests is fully utilized and there seems to be no wood residues. This type of project can be implemented only in less-densely populated area where demand for fuel wood is smaller. Just buying charcoal in the market and storing the charcoal cannot be carbon sequestration project. As mentioned earlier, in the process of carbonization, 60 to 70% of carbon was disappeared to the air (or in the form of volatile matter). CDM project can implemented in where the baseline is clear.

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2. Wood residues from plantation forests (Acacia mangium) In West Java, Acacia mangium wood was used for furniture, not for pulp. 2m logs with above-10cm diameter (average diameter of tip and bud) are sold. Residues are sold as fuel wood or given to village people for free. Local people often produce charcoal from the given wood residue. Table 35 shows the amount of total aboveground biomass and wood residue and amount of pure carbon stored in charcoal. Data from West Java indicate that after 8 years, the amount of wood residue did not increase. Low stand density in West Java was because of thinning operations. According to the data shown in the table, amount of wood residue are proportional to stand density.

Table 35 Amount of wood residue (oven dry weight) and pure carbon stored in produced charcoal (logs of above 10cm diameter are extracted) Location PT. Perhutani, West Java, 10 year-old stand PT. Perhutani, West Java, 8 year-old stand MHP, South Sumatra, 9 year-old stand

Stand density (trees/ha)

Total aboveground biomass (t/ha)

225

Wood residue: Stem(