TCP/CRO/3101 (A) Development of a sustainable charcoal industryINDUSTRIAL CHARCOAL PRODUCTION June 2008 Zagreb, Croatia www.drveniugljen.hr FAO TCP 3101: Industrial charcoal production This publication is a part of deliverables of the FAO project: TCP/CRO/3101 (A) Development of a sustainable charcoal industry Editors: Dr Julije Domac Dr Miguel Trossero Production: North-West Croatia Regional Energy Agency This project was launched in July 2006 within FAO Technical Cooperation Programme withthe objective to assess the current status of the charcoal production in Croatia, in order to develop a programme for the revitalisation of this industry. Apart from recommendations and best solutions for the technological modernisation, the programme will provide guidelines for the production improvement and amplification with a holistic approach. Ministry of Agriculture, Forestry and Water management is responsible for the project execution on behalf of the Government of the Republic of Croatia. FAO TCP 3101: Industrial charcoal production INDUSTRIAL CHARCOAL PRODUCTION Project Technical Officer: Dr Miguel Trossero National Project Co-ordinator: Dr Julije Domac Contributing Authors: Dr Roland Siemons 4 ...............................................................................FAO TCP 3101: Industrial charcoal production CONTENTS ACRONYMS AND ABBREVIATIONS.........17 3..1 CARBO TWIN RETORT ....................................................................7 1..............17 3............................7 1.........................................................................26 LITERATURE .......................6 UNITS ....................::::::::::::::::::::::::::::::.........................................................20 3.................1 ECONOMIC CONSTRAINTS ....................2 WAGGON RETORT .........3 O..........1 KILN METHODS ..............9 2 CHARCOAL PRODUCTION PROCESSES .......14 3 EXAMPLES OF RETORT BASED CARBONISATION TECHNOLOGIES ...2 TECHNOLOY DEVELOPMENTS ..T CALUSCO TUNNEL RETORT ................................................................................................................2 RAW MATERIAL ...............................4 LAMBIOTTE .....2 RETORT CHARCOAL PRODUCTION ..........1 GENERAL OVERVIEW OF CHARCOAL PROPERTIES ........6 1 PHYSICAL AND CHEMICAL PROPERTIES OF CHARCOAL .................................30 ANNEX A ADDRESSES ......................................E.....................................................................11 2.........................................22 4 FUTURE DEVELOPMENTS IN INDUSTRIAL CHARCOAL PRODUCTION ....................................11 2.............25 4...................21 3...................................31 5 ......................................24 4........................................................ MJ/Nm ) UNFCCC United Nations Framework Convention on Climate Change MC moisture content (-) m mass (g. K) t time (s. yr) W physical work (J/s) ηenergy efficiency (-) ρ density (kg/m ) UNITS Area 2 3 o 3 3 ha hectare (10. solid matter (bulk volume less voidance) m a cubic metre.000 m ) Distance m metre Energy J Jouletoe tonne oil equivalent (41. 8760 h) Volume 3 3 litre m b cubic metre.868 TJ)W Watt (=J/s)Wh Watt-hour (3600 J) Mass g gram gx gram of matter at a reference moisture content (MCw) of x %m t tonne (1000 kg) tx tonne of matter at a reference moisture content (MCw) of x %m Temperature o C degrees Celsius K Kelvin Time d day (24 hours)h hours secondyr standard year (365 days. h. MJ/Nm ) T temperature ( C. MJ/kg. MJ/kg. t) NCV net calorific value (GJ/t. solid matter including its pores (apparent volume) Prefixes m milli (10 ) c centi (10 ) k kilo (10 ) G Giga (10 ) 6 9 3 -2 -3 3 M Mega (10 ) 6 . bulk volume m s cubic metre. d.FAO TCP 3101: Industrial charcoal production ACRONYMS AND ABBREVIATIONS AC ash content (-)GCV gross calorific value (GJ/t. 1 GENERAL OVERVIEW OF CHARCOAL PROPERTIES The quality of charcoal depends on both wood species used as a raw material and of the proper application of the carbonisation technology.” Charcoal intended for barbecue typically contains 20-30%m of volatiles.3468 US Dollar 0. and burns without flame. and does not crush. on the other hand.1359 0. The bulk density of charcoal does not only depend on the apparent density but also on the size distribution. Charcoal made from softwood.FAO TCP 3101: Industrial charcoal production T Tera (10 ) P Peta (10 ) E Exa (10 ) Subscripts 1 with energy units: primary energy 2 with energy units: secondary energy b with m : bulk volume (equal to the specific volume times [1-porosity]) d on a dry basis daf on a dry and ash-free basis e electric G gross M mechanical m with %: mass percent N net p at constant pressure s with m : specific (or true) volume of solid material th thermal v at constant volume v with %: volume percent w on a wet basis Currencies Rates on Tuesday. Charcoal produced from hardwood like beech or oak is heavy and strong. The gross calorific value (GCV) is usually in the range of 29-33 GJ/t. the fixed carbon content is 78-90 %m.7612 1 5. it is jet black in colour with a shining luster in a fresh cross-section.5929 Croatian Kuna 0. February 16. and is in the range of 180-220 kg/m b.3136 7. is soft and light.45 t/m a. It floats in water.28 t/m a. 7 2 3 3 1 3 3 . whereas metallurgical charcoal often contains 10-15%m (or even less) volatile matter. 2007: Currency names Euro US Dollar Croatian Kuna Euro 1 1.1785 1 3 3 18 15 12 1 PHYSICAL AND CHEMICAL PROPERTIES OF CHARCOAL 1. Good quality charcoal was characterized by Chaturvedi as follows: “[It] retains the grain of the wood. that of pine charcoal 0. Hence. The density of beech charcoal is 0. is a bad conductor of heat and electricity. nor does it soil the fingers. taking ash contents into account. It is sonorous with a metallic ring. FAO TCP 3101: Industrial charcoal production This carbon is a finely crystalline and practically free of sulfur. oxygen. fixed carbon = total charcoal . Standards for barbecue charcoal and charcoal briquettes. wet basis < 8% Granulation [d > 80 mm] < 10% [d > 20 mm] > 80% [0 mm < d < 10 3 mm] < 7% Bulk density > 130 kg/m b Charcoal briquettes: Carbon (fix). consisting of hydrogen. Major quality issues are reviewed in Table 1. dry basis < 8% Moisture. Charcoal also contains volatiles that may escape at elevated temperatures (obviously above the charcoal manufacturing process of approximately 400 C). Moisture content varies between 5 %m-8 %m. the amount being dependent on ambient temperature and humidity. for dry basis values. It assumes the volume of a piece of charcoal. Charcoal also contains water. dry basis < 18% Moisture. including the pores. wet basis < 8% Granulation 8 3 . 3/ These are dry basis values. and nitrogen. dry basis > 60% Ash.5-5%m. In the European Union the quality of barbecue charcoal is specified in standard EN 1860-2:2005. Charcoal: Carbon (fix). 4 o 1/ kg/m a is the apparent density. Ash content is approximately 1. Approximately.volatile matter ash. according to EN 1860. 2/ Cited by Foley (1986). dry basis > 75% Ash. Tabel 1. 4/ EN 18602:2005. plastic. 5 o 5/ As experienced by and hypothesised by Mok et al. However. With regard to yield. To develop an understanding of this phenomenon. The question as to what extent the wood is to be dried prior to carbonisation. sawdust. fruit stones. stone powder. Yet another aspect is.g. pitch. petroleum. wood shavings. that drying always comes with a cost. should be analyzed from two angles: attainable yield and productivity. in actual practice it was found that the presence of moisture may have strong positive effects on charcoal yield. In these cases the resulting charcoal needs to be briquetted. their residues. but also for heating and evaporating all of the water contained in the wood as well. nutshells. one should go beyond thermodynamical equilibrium theory. Mok and Antal speculate that this is due to the moisture’s role as a catalyst in charcoal formation.FAO TCP 3101: Industrial charcoal production Suitable for BBQ equipment of EN 1860-1 [d < 20 mm] < 10% Binder Combustion gases cause no health hazards in contact with food. slag. and similar products can be used. but then one has to sacrifice part of the material that otherwise could have been turned into charcoal. nuts. 1.2 RAW MATERIAL Both hardwood and softwood can be used as a raw material. Theoretical thermodynamical equilibrium analysis for an ideal process without heat losses shows that the charcoal making process does not require the wood to be dried further than about 50%m (w) prior to the carbonisation process. Chemical burner sustainers not permitted. corn cobs. etc. and its evaporation takes time. Also. To some extent the presence of moisture has a negative influence on productivity. cotton seeds. One can also make charcoal from wood at higher moisture contents. their wood contains 50%m-60%m water (on a wet basis).e. and analyze carbonization at the level of secondary chemical reactions of the vapours released during carbonization. 1992) and by Antal and 9 . glass. Lump wood is used directly from the forest or from wood processing industries (i.: fossil coals and derivatives. This is because the heating of water. Charcoal and Charcoal Briquettes: Inadmissible additions Specific rules for presence of substances like e. When trees are being cut. the basic issue is whether the volatile matter released during carbonisation does not only carry sufficient energy for heating the dry-matter wood to the required processing temperature of about 400 C. such as slabs and off-cuts). bark. Binder is of food grade quality. 1) does not play a role in the estimate of the dried mass. say MCw. Note that the original moisture content (MWw. respectively. and therefore that of the wood input counts. In that case the equivalent mass of a dried stère can be estimated from: 1 − MCw.2 10 .2. wood is most often sold in volumetric units. however. If that is not the case. The mass equivalence of a stère of fuelwood. can be estimated as follows: ρ 8 3 7 s. This is.0 is specific for the wood species. the mass of the output. Usines Lambiotte recommend an MCw as low as 10% for the Lambiotte Shaft Furnace. is dependent on the wood species. and MWw.0 is the density of the dry solid wood. whereas a stère of pulpwood is approximately 0. A traditional unit for wood is the stère.1 ≈ 1 − MCw. and the optimum moisture content depends on the technology employed. ρs. while stating that “the details of the chemistry that underlies the improved yields are not understood. which is equal to 1 m of stacked (outer) volume. kg 1stereMC w.2 065 MC w. under such a circumstance the initial moisture contents and the mass of the “wet” stère should be determined.0 . after having been dried to any moisture content. An MCw of 30% in the wood feed gives good results in the Carbo Twin Retort. or as bulk (or stacked) volume. However.72 m s.” 8 There are thus several opposing effects. 6 For the charcoaler. A stère of fuelwood is estimated at 3 3 0. and on the moisture content of the wood. because the density of the dry wood is supposed to be known.1 and MCw.FAO TCP 3101: Industrial charcoal production Grønli (2003). The density of the dry solid wood.2 where ρs. Conversion of these units of volume to units of mass. the mass of the dried stère can still be estimated.2 are the wet basis moisture contents of the fresh and the dried wood. To make it even more complicated wood volumes are either given as solid volume.65 m s. 7/ Padovani (2002). E. volatile matter content and ash content are parameters that are different with producer and production technology. Premery.g.. For a pile of wood chips. is yields.1 6/ Mares. G. both charcoal and biomass feeds can be of varying qualities. moisture contents vary with lot.65 is based on the assumed voidance of 35% for a stacked pile of fuelwood (Padovani. 2002). and technologies are characterized in tems of economics and other parameters. Unless these 11 .8/ The expression disregards shrinkage of solid wood upon drying.28). Padovani substitutes a voidance of 28% (and thus a factor of 1-0. Usines Lambiotte. Yield is generally defined as the mass ratio of charcoal made and biomass fed: m Yield = charcoal m biomass feed However. climate and producer. The factor of 0. J. 1999.FAO TCP 3101: Industrial charcoal production mass2 = mass 1. France. A particular topic that needs some discussion to enable a proper technologyevaluation. 1 − MC w. 10 2 CHARCOAL PRODUCTION PROCESSES In this chapter. Personal communication to Antal and Grønli (2003). Also the fixed carbon contents. operating principles are being discusse. but it has been abondoned during the first half of the 20 century. Kilning methods for charcoal making are a strong emitter of polluting gases (mainly unburnt methane and other carbon compounds). only few research has been reported in which this statement is underpinned. Carbonisation rates (or the Cfix content) differ. 2. In the USA this technique was also widely used for the manufacture of metrallurgic charcoal. sand and mud.". Missouri kilns. Smith et al.. e. . The technology is still widely used. In practice.. managed by Horner Charcoal Company (Taneyville. were widespread up until 1975 and later. Beehive kilns can be found in large industrial complexes.de).FAO TCP 3101: Industrial charcoal production quality parameters are further specified. these claims are seldom related to the moisture content of the wood. Some examples of such improved kilning techniques are Missouri kilns. and there can be contamination with ash. http://www. at least in the state Missouri. So. part of the feedstock is offered to start and control the process.g. At least one example of a set of Missouri kilns was found to be currently in operation. however. and they vary with the skills of the operators. both in developing countries and in industrialized countries.1 KILN METHODS Traditionally. Missouri). With the kiln method.. There is a direct contact of the combusted pyrolysis vapours with the biomass feed (internal heating). The range of yields and qualities is narrower (tending towards higher yields and better qualities) for the improved kiln methods.holzkohlewerk. Also the improved kilning techniques are widely used today. Also the quality of the charcoal thus manufactured is variable. charcoal is being made in mound or pit kilns. making charcopal for the steel in dustry in Brazil. Yields are usually in the range of 5%-20%. Aucamp (1979)11/ Some German and Austrian charcoal manufacturer advertise this technology. Köhlerei Jatznick 12 . However. In Germany: Holzkohlewerk Lüneburg (Hamburg. observed that "extremely good charcoal yields are commonly claimed by South American charcoal producers. Already Violette (in the 1850s). and Brazilian Beehive kilns. one should be aware that claims of high yields should be carefully evaluated in view of these quality aspects.10/ Aucamp. Over the past century the kilning technology has been improved. Argentine kilns. carried out emission tests for the following traditional 12 th 11 10 9 9/ Violette (1853). a yield is quite meaningless as an indicator of a technology. made note of this issue. thefixed-carbon content of the charcoal. There is not much capital involved in mound and pit kilning technology (apart from labour and feed stock).e.de). i. (Michelbach. Improved kilning techniques do involve substantial investments.koehlerei-jatznick.holzkohle. Rice Husk Mound. 1992).12/ 500 Missouri kilns were reported by Deglise and Magne (1987). 15 14 13 Figure 2. Productivity is also low. InAustria: Johann Hochecker. 13 .FAO TCP 3101: Industrial charcoal production (Jatznick. Traditional mound kiln in Liberia (Photo: Roland Siemons. Emissions to air were also reviewed by the USA Environmental Protection Agency. 1 1 kilning methods: Mud Beehive. www. to reduce polluting emissions to an acceptable level under the USA EPA regulations. Earth Mound. Also improved kilning methods were studied by them. www.at). the Missouri kilns operated by Horner Charcoal Company were facilitated with an after-burner system. In 2004. the Brick Beehive and a Single Drum. et al. Pennise.gov/eiera/index.FAO TCP 3101: Industrial charcoal production 13/ Smith.7 Charcoal) 14 .dnr. Khummongkol. (1999). Figure 3. Wise River Ranger District. Beehive kilns in Canyon Creek. http://www. M. P. A Missouri kiln. Emission Factor Documentation for AP-42. 15/ Source: Environmental Improvement and Energy Resources Authority (Missouri Department of Natural Resources). 14/ EPA (1995). D. Montana (USA) Figure 4.mo. (Source: EPA.html. Section 10. Antal’s flash carbonisation technique (in the R&D phase). Some indicative names of existing (or commercially lost) retort processes for the carbonisation of lump wood are: Arkansas or Waggon Retort. For the carbonisation of biomass grains. In a retort. However. Badger-Stafford Process (no longer in use). There are many methods of implementing the retort principle. Degussa). Degussa Retort (Reichert Retort). In these retort processes. O. and few of them are commercially offered. Waggon Retort. Exceptionally additional fuels are used. and methanol. the development of retort technologies in the past may have had other reasons than yield optimization alone: separation enables the manufacturer to produce a variety of chemicals. the pyrolysis vapours are separated from the feed material.2 RETORT CHARCOAL PRODUCTION Most modern industrial charcoal makers use retorts for their process. the Pyro rotary furnace (being demonstrated). SIFIC Process and the related Lambiotte Retort. for start-up and in case of feed material that is too wet. such as acetic acid. the wood feed is either externally heated through a shell (Carbo Twin Retort. 15 .T Calusco Tunnel Retort. as firms who employ them halt their production over time. Only the vapours are used to provide the energy sustaining the process. Most of them have been developed by the charcoal producers themselves. e. Direct contact of the biomass feed with oxygen from air is being prevented.E. before being combusted.FAO TCP 3101: Industrial charcoal production 2.E. the following indicative names are found: Herreshoff Furnace (storey furnace). If carried out properly. In this manner it ensured that the entire biomass feed is available for the conversion into charcoal.g. Today. VMR (no longer in use) and the O. or through direct contact with the combusted pyrolysis vapours (Lambiotte.T Calusco). An implication is that knowledge of the processes fades away. Carbo Twin Retort. the production of these by-products is no longer viable in view of of the competition with other manufacturing processes. wood vinegar. such as saw dust or nut shells. charcoal yields from retort processes can be very high. A continuous multiple hearth kiln for charcoal production (Source: EPA. Figure 6. 16 . Washington.7 Charcoal. EPA. Emission Factor Documentation for AP-42. Section 10.FAO TCP 3101: Industrial charcoal production Figure 5. The retort principle for carbonization. 1995. Bodenfelde (DE) Waggon Retort (since early 1900) Carbo Twin Retort (since appr. the application of these criteria shall take some time. Green-Charcoal.A. high quality Pollution: gases are burnt during the process. whether they are in operation today.T Calusco (tunnel retort) (ITB) Lambiotte Shaft Retort Batch Retort 3 EXAMPLES OF RETORT BASED CARBONISATION TECHNOLOGIES In this chapter.FAO TCP 3101: Industrial charcoal production Figure 7. Mortera (I) Prémery (France) Belgium Less S. Important criteria for their selection are. December 2004) Retort charcoal production technologies are characterized by: Mechanised production 20%-30% yield of charcoal by weight Controlled. and whether the technology can be supplied. A continuous rotary retort (Pyro 7) (Source: Pro Natura International. Of some 17 . retort carbonization technologies are used by: Belišće (HR) Carbo Group (NL) Green Coal Estonia (EE) Carbo France (FR) Milazzo. 1990) Carbo Twin Retort Carbo Twin Retort O. As it turns out. Chemviron). (CZ) ProFagus (former Degussa. high capital investment In Europe. some retort based carbonisation technologies are described. thus preventing the release of noxious gases Spare energy may be available for steam generation or for drying Stationary.E. that vessel removed. This chapter therefore deserves an update later. if the vessels are used for pre-drying). Carbonisation of one vessel takes 8-12 hr. For hard wood it is approximately 900 tonnes of charcoal per year. The direction of gas flows is swithched by making use of valves. depending on wood properties. 10. vessels now containing charcoal. external energy source are not needed except for initial start-up. see Figure 8) is loaded with two 5 m vessels containing the wood feed. This operating principle is sketched in Figure 9. the carbonization cyle of which are effectively operated in counter-phase. France. South Arica. The latter is being discussed here. Singapore. Senegal. When. The production steps are shown in Figure 10.FAO TCP 3101: Industrial charcoal production technologies it is not immediately clear if they can be delivered by a technology supplier. and replaced by another that has been filled with fresh wood. 3. one vessel is to be removed every 4 hours (6 vessels per 24-hours) from the Carbo Twin Retort. Its capacity is determined by the number of batch runs that can be carried out in a given period of time. If the wood is sufficiently dry. Nigeria. as chrcoal trader. Oman. The Carbo Twin Retort system is currently in use several countries: the Netherlands. The pyrolysis vapours released from one hot carbonizing vessel. 3 16 18 .g. e. are combusted to heat-up another vessel freshly loaded with wood. Continuously operated. The process is to be repeated interminably. are placed in a sand lock and left to cool for a period of 24 hr. Estonia. When removed from the Carbo Twin Retort. after several hours the latter has reached carbonization temperature and emits pyrolysis vapours suitable for combustion. and as supplier of briquetting and carbonization equipment. Therefore. An oil burner is used to provide heat for initial process start-up. The Carbo Twin Retort is a semi-continuous production module. The Carbo Twin Retort (for a sketch.1 CARBO TWIN RETORT The Carbo Twin Retort was developed by Ekoblok/Carbo Group. one Carbo Twin Retorts needs a total of 6 vessels to keep the system running (and more. the charcoal in the first vessel is ready. Ghana. which is active as briquette and charcoal manufacturer. Cross-section of the Carbo Twin Retort.FAO TCP 3101: Industrial charcoal production 16/ For a full address see Appendix A. Figure 8. Exhaust gas Exhaust gas 19 . Thus the emission of other polluting gases. This is because the vapours are completely combusted into CO2 and H2O.FAO TCP 3101: Industrial charcoal production Figure 9. such as CH4. The charcoal yield. The optimum moisture content is about 30% (wet basis). Operating principle of the Carbo Twin Retort. CO and higher C-compounds is negligeable. complying with EN 1860. In comparison with kilning technologies for charcoal production. is 30% or higher. The temperature of the exhaust gas from the Carbo Twin Retort is about 580 C. the Carbo Twin Retort technology is very low on emissions to air. and suitable to drive a thermal wood dryer. 20 o . The Carbo Twin Retort is fed with wood that has been cut to sizes in the range of 30x30x10cm. The process lost ground due to the development of semicontinuous systems like those of Lambiotte and Degussa. in view of obtaining project finance.000 1. the technology performs well.000 5. During the late 19 th th and early 20 centrury it was widely used in Europe and the USA.FAO TCP 3101: Industrial charcoal production Also in terms of particulate emissions.000 Total 1. Waggon Retorts are suitable for a variety of feed sizes. The complex operation and the changing heat exposure of the various plant components result in relatively high maintenance. if the technology is replacing traditional kilning technology. Tabel 2.000+ x 3. split roundwood and slabs from sawmilling. 3. piece length may be upto 1 to 1.2 WAGGON RETORT The Croatian firm Belišće operates a Waggon Retort system. Units Unit cost (€) Costs (€) Open building Carbo Twin Retort 3 360.E.3 O. The Waggon 1 9 Retort system was particularly noted for high maintenance costs of the steel waggons and the shell of the retort itself. The system is also known under the name of Arkansas Retorts.080. Indicative cost estimate for a Carbo Twin Retort system.T CALUSCO TUNNEL RETORT 21 . An indicative cost estimate is given in Table 2.000 60. which showed lower overall operating costs. The avoidance of GHG emissions. complying with the strict Dutch emission regulations. The minimum number of sets of retorts and coolers to ensure a steady supply of wood gas for retort heating is six but much larger numbers were not uncommon. The wood is charged into steel waggons with slatter sides.145.000 Hoist and rail 1 5. The waggons fit the dimension of the retort rather closely. The waggons roll into and are removed from the retort on steel rails which connect with a cooling chamber of the same dimensions as the retort and built directly facing it so that the waggons after carbonisation can be drawn quickly into the cooling chamber and sealed for cooling.000 Fork lift with rotator 1 60. The wood should be dried to about 25% moisture content for good results. may be a relevant issue. supervision and operating costs.2 metres. including roundwood. 45 m long. The tunnel. Impianti Trattamento Biomasse in Calusco d’Adda (Italy). producing 6. varying with the characteristics of the feedstock used. From there. 2) carbonized and 3) cooled. operated by the Société Usines LAMBIOTTE. The third part is cooled and used to prevent the cooling charcoal from ignition. Another part is used to indirectly heat the carbonisation chamber (via a heat exchanger). 20 3. the hot combustion gases are separated into three.T. and said to be operational in at least two places: Milazzo and Mortera. The operating principle. 3 Figure 11.000 tons/year of charcoal each. the Prémery plant produced 25. When still in production.FAO TCP 3101: Industrial charcoal production The O.T Calusco Tunnel Retort has been described in the literature. The carbonization vapours are removed from the carbonization chamber and combusted in an external furnace.E. and from various sources it has been confirmed that the firm currently no longer in existence. Wood is put in 12 m trolleys that are moved through a tunnel. It was closed down in 2002. One part drives the the drying chamber where it is in direct contact with the wood feed.4 LAMBIOTTE The largest operational Lambiotte Retort was located in Prémery (France). The total residence time within the tunnel is 25-35 hours. The walls of the trolleys are made of perforated steel. The chambers are separated by a door.000 tons/year of charcoal from oak wood in 22 17 . O. is shown in Figure 11. The technology is said to be developed by I.B. showing a large resemblanc with the Arkansas waggon retort. but its operation could not be confirmed in the course of this project. is divided in three chambers where the wood successively is being 1) dried.T Calusco Tunnel Retort system.E. The Lambiotte carbonisation process consists of a continuously operated shaft furnace. the SIFIC and the CISR system. to serve as a heating medium for drying and carbonisation. the wood passes a drying zone. to remove certain commercial components. The carbonization vapours are removed through the top of the retort. One part of the combustion gases is injected in the middle of the retort. one for the drying/carbonisation stage and one for the cooling stage. The Lambiotte process being continuous. and the moisture content should be below 25% (wet basis). Both systems have two closed gas-loops. There exist two variants of the Lambiotte process. Further enquiries are being made (particularly in Belgium)whether the Lambiotte technology can be supplied from elsewhere. 23 . On its way down. Wood enters the retort from the top through a lock-hopper. The remaining gas is burnt in a combustion combustion chamber. The SIFIC process can be run with by-product recovery. The wood should be prepared into lieces of about 10 cm. a homogeneous quality of wood feed is essential. the carbonisation zone and and a charcoal cooling zone. In the SIFIC variant. Another part is cooled and re-injected at the bottom of the retort for cooling the charcoal. the condensable fraction is taken through coolers and scrubbers.FAO TCP 3101: Industrial charcoal production two shaft retorts. 22 4 FUTURE DEVELOPMENTS IN INDUSTRIAL CHARCOAL PRODUCTION In a final chapter we review possible trends that apply to the charcoal making industry. and into the options for improving the charcoal making 24 . To this end we look into the development of end-user markets.FAO TCP 3101: Industrial charcoal production 17/ Latest available address in Appendix A. 1 ECONOMIC CONSTRAINTS The traditional markets for charcoal are: Metallurgical industries Purification (active coal) Barbecue in industrialized countries Household cooking in developing countries. The position of charcoal as a household fuel in developing countries is largelydue to its suitability as a relatively clean fuel for urban environments (moderate local emissions) and its low costs for the end-user (also taking into account the low-costs of the appliances needed for its use). for descaling of metal sheets and wires. The prospective developments of existing markets are not likely to trigger innovative technologies. Charcoal is also usedas a carburizing agent. for tempering. However. including fuels for the electricity sector. However. These markets are gradually growing. mainly in urban areas In the first three markets. 4. the position of charcoal would be based on two properties: its biological origin (and thus its suitability as a sustainable carbon-neutral fuel) and its potential of contributing to the politically desired diversification of supplies. Just a few examples taken from a presentation for the UNFCCC: 22 18/ Including the production of ferrosilicon. Torrefied wood is also occasionally mentioned as an alternative fuel product. the role of charcoal is based on its unique properties that cannot be easily replaced by alternative products. charcoal could become an alternative for mineral coal and fuel oil. although a 2 MW pilot plant is currently being built in Uganda and is planned to be operational in fall 2008. The product is not yet commercially offered at an industrial scale. pure silicon. A new market for sustainable industrial fuels A new market for charcoal could be that of industrial fuels. Alternative products that could serve the same energy market include pyrolysis oil and wood pellets. 21 20 19 18 Wood pellets are traded as a biomass substitute fuel for coal in electrical power plants. Charcoal is also used 25 . charcoal is likely to be phased out as a common cooking fuel.FAO TCP 3101: Industrial charcoal production technology. and refining copper. Here. The potential of pyrolysis oil for the energy market was elaborated by Siemons in 2002. With ongoing development of these developing countries. charcoal is not the only product that can play this role. In this market. whether it can be offered attractively in the market has not been analyzed nor demonstrated yet. ferromanganese. This is equivalent to an effective power of 420 MW (assuming a conversion efficiency of 45% and 7000 full-load equivalent operational hours annually).g.g. handling. and that charcoal is less attractive than pellets.2 1300 22400 0. and 910. E. A comparison of energy density.5% Pyrolysis oil 17. 20/ Siemons (2002). pulverization).J. charcoal is less costly to pulverize than pellets. (2006a)and (2006b).5 650 11400 0. On the other hand. also The Netherlands are substantial importers. suggests that in terms of transportation costs. In 2006. Danish power plants used 570.000 t of straw pellets annually.000 t of wood pellets in 2001. Tabel 3. Additionally.50% Charcoal (lump) 29 200 5800 1.50% Wood pellets 17.10% Coal 25 1000 25000 13% Development of the market for sustainable industrial charcoal-based fuels 26 3 . especially if theyare supplied from within the region. 2 3 Unit 2 (510 MWe) of Avedoere Power Station in Denmark combusted 300.000 t of wood in the form of pellets and chips. .5 130 1890 5% Straw pellets 15 600 9000 5% Wood chips 10.J.Denmark). See. 3 Fuel typeNCV (MJ/kg) Density ( kg/m b) Energy density Ash (d) (MJ/m b) Straw 14. Indicative parameter values are given in Table 3. e. 21/ The plant of Clean Fuels Kakira Ltd...5 300 3200 0.FAO TCP 3101: Industrial charcoal production in blast-furnaceprocesses. its usage could be more attractive than pellets. Denmark is not the only European country that produces and imports biomass pellets as a substitute for fossil fuels. this argument only applies when large transportation distances are involved.22/ Gert Schultz (Energi E2 . 19/ Torrefaction. M. review is not currently available. pyrolysis oil is the most attractive biomass derived fuel. K. A comparative study is not known.000 t of pelletized straw. An unsubstantiated source claims the existing European consumption of 8 million tonnes of pellets annually. as a biomass fuel treatment technique (low-temperature carbonization) has certain advantagesin view of energy use for fuel preparation (drying. Unit 2 (82 MWe) of Amager Power Station in Denmark combusts 150. as well as their cost-effective calorific value and density. So. will supply local industries with pyrolysis oil as a substitute for Heavy FuelOil. combustion). et al. Prins. Ptasinski. for power plants and industries such as cement works. Some trading properties of bio-fuels in comparison with mineral coal. 23 A published market These fuels are suitable for trading because of their ease of application (storage. as in the norms for barbecue charcoal (EN 1860) are not an issue here. do not apply to fuels used in the industrial fuel market.FAO TCP 3101: Industrial charcoal production might stimulate a particular development of carbonization technologies.. 27 25 . After all. Henrich and Dinjus (2003) Scale-economy Lambiotte (Belgium) offers systems of 2000 and 6000 t of charcoal annually. scale-up (realizing economies of scale). Yield As discussed in previous sections. This would be particularly caused by specific preferred product properties. Details are given in several papers written by Henrich et al. the preferred characterisitics of lump charcoal. e. proposed by the Karlsruhe Research Centre FZK. with regard to simplification (reducing capital costs). or processing yield (reducing operational costs)? 23/ http://pressherald. Note that this indeedappears to apply if the issue of the fixed carbon content of the charcoal is properly taken intoaccount (as discussed in Chapter 2). The analysis will not be made here. there is a distinct difference in yield between traditionalkilning techniques (usually in the range of 5%-20%) and industrial retorting techniques(20%-30%). is the manufacture and trade of slurries from charcoal and pyrolysis oil. as being used in the barbecue market.mainetoday. Carbo Group systems of 1000 t/a. Larger plants using the Carbo Twin Retort operate multiple retorts in parallel (One operator handles 10 of them. A promissing industrial concept.com/business/stories/070415woodpellets.g. as well as the wood acquisition risk for larger carbonization plants. 24 4.ht ml24/ E. Granualation in sizes below or above certain sizes and a specific fixed carbon content.2 TECHNOLOY DEVELOPMENTS May further developments of carbonization technologies be expected.g. provided the charcoalers are well-skilled in their trade. It is not known whether there is an interest in scaling up the Lambiotte system to even larger capacity. Schenkel (1998) argued that high yields are also feasible by means of kilningtechnologies. at Carbo’s own production facility). Whether scale-up can actually result in improved economies of scale is a question that cannot be answered without a thorough analysis. One of the parameters that provides a counter indication against scale-up is the increased costs of raw material (wood). The Carbo system cannot be scaled up easily (being a balanced systemconsisting of two batches operated in counter-phase). i. An intriguing question concerns the role of secondary vapour reactions for the formation of charcoal. although the issue seems to be simply this: what are the improvements in yield that we may expect from further R&D?.26/ Antal. like for commercial charcoal. and this was also recognized by Antal and Grønli.FAO TCP 3101: Industrial charcoal production Whether the achievement of higher yields is technically feasible. But still . a theoretical approach should be quite complicated in order to be valid.: How is the product defined? Charcoal is broadly determined as a product that contains fixed carbon at a ratio larger than 70%. (1998).08 CH4 25/ Schenkel. The relevance of those reactions is supported by a host of scientific reports. there are ambiguities that arise immediately. was investigated by Antal andco-workers.2 define the thermal production conditions by pressure and temperature. Varhegyi and Szekely (1990). but merely on the thermal equilibrium of their own postulated final products (CO2. but the precise chemical composition. they arrive at the following molar and mass balance (it is not a reaction mechanism!): C6H10O5 6 0.7%/75%).7% (being the mass ratio of 3. so that a fixed carbon content of 75% results. and reported in two scientific papers. C (graphite).65 H2O +1. They reviewed past research.74 C + 2. since we observe that this charcoal consists purely of fixed carbon in the formof graphite. Upon carbonization. and their ownthermal analyses and experiments. H2O. A clear over-simplification of the matter was presented by Antal and Grønli (2003) by a determination of the equilibrium products of cellulose pyrolysis at varying pressure and temperature (Figure 13). We cannot agree with Antal and Grønli that this would be an indicator for “the theoretical carbon yield” of the carbonisation process. Assessing the maximum theoretical yield is not a simplematter. CH4 and CO). and physical structure vary strongly with process characteristics and raw material . At first sight. For a processing temperature of 400 C and a pressure of 1 MPa (10 bar).17 CO2 + 1. One could propose to extend the model by allowing an incomplete reaction (prior to achieving equilibrium). or should one also consider secondary carbonization reactions of vapours that result in precipitation of fixed carbon? Clearly.e. and conclude that the yield of charcoal would be 27. does a piece of wood simply disintegrate into charcoal and vapours that are gone.is this the theoretical maximum? It is hard to say. Antal and Grønli (2003).3 analyse the reaction thermodynamically. Bertaux et al. The maximum theoretical charcoal yield would then become 37% (= 27.74 mole of carbon per mole of cellulose). one would perhaps approach the issue as follows:1 define the raw material and the product. Mok.However. because the equilibrium calculations of Antal and Grønli are not based on a chemical reaction model. 28 o 26 . It seems possible. In view of the results of their equilibrium model for graphite formation (compare Figure 13). that the reported effect is the result of increased vapour residence time that may occur in a high-pressure test device.FAO TCP 3101: Industrial charcoal production Figure 13. We shall not summarize the entire discussion here. Antal et al. the reader is referred to the indicated papers. They do draw that conclusion (‘high pressure. do not discuss that hypothesis. Therefore. conclude that it would be favourable to increase processing pressure above 1 bar. In their reviews. Instead. . by Antal and Grønli (2003). Antal and co-workers considered a large number of parameters. it is surprising that Antal et al. Results of the equilibrium model of cellulose carbonization. hence high yield’) though on the basis of their interpretation of experiments. but at least the results obtained by Violette (1853) (in view of the test procedures employed by him: carbonization in a sealed glass tube) are perhaps best explained in this manner. we put forward that favourable reaction circumstances for carbonization are these: Slow vapour removal from charcoal matrix Vapour exposure to high-temperature charcoal Options for optimised 29 . and thus is caused by secondary vapour reactions contributing to charcoal yield. 221-225. 1995.r3. 1979. Res.P. 28 LITERATURE Antal. in Hall. Requirements and test methods. The art. It is described on a website. D. Reported results.. Overend.. pressurized with air at 10 bar. Office of Air Quality Planning and Standards. London. Mochidzuki. R.FAO TCP 3101: Industrial charcoal production reactor configuration are then: Closed container Vapour flow control The first of these optimizations is indeed employed by Antal. in the so-called Flash Carbonisation process. Grønli. S.. the concept consists of a vessel packed with biomass. In brief. 30 27 . Emission Factor and Inventory Group. 3 May / June 1990. Foley. 1619-1640. Res. Energy & Fuels (An American Chemical Society Journal).: Charcoal Making in Developing Countries. but rather because of the prolonged vapour residence time that can be achieved in a closed reactor vessel. and Magne.edu/bio. Mok. New York. not so much though in view of increased reaction pressures. Szekely. P. L. and M. V Encontro Nacional de Florestadores. Antal. Large Scale Charcoal Technology. Whether this Flash Carbonisation process is the answer.hnei. and ignited electrically. M. 4. Ind. solid fuels and firelighters for barbecuing. L. Environmental Protection Agency. Chem. and L. jr. S. K. Earthscan. Chem. Ind. Antal. Varhegyi and T. Section 10.asp#newsitem. 42. EPA. 3690-3699. Barbecue charcoal and barbecue charcoal briquettes. it seems an interesting R&D route. 2003. In any case. and in a paper. at the Renewable Resources Research Laboratory (Hawaii Natural Energy Institute). . from the data reported in the referred paper). p 1. Washington. Aucamp. Jr. Eng. are an average charcoal yield of 34% an average fixed carbon yield of 29%. 42. 1987. 2003. 1986. M. Emission Factor Documentation for AP-42. H. M. X. Pyrolysis and Industrial Charcoal. G. Such results are not yet very dramatic in comparison with state-of-the-art industrial carbonization technologies. still remains to be seen. U.. Biomass.. J. Flash Carbonization of Biomass. J. Deglise. so far. and Paredes (2003). and Antal. and an average energy efficiency of 60% (derived by the author of this report. Gramado & Canela. Review of Methods for Improving the Yield of Charcoal from Biomass. S.7 Charcoal. Eds. Mochidzuki. J.hawaii. W.O. 27/ http://www.. science. G. EN 1860-2:2005 Appliances. jr. Eng. and technology of charcoal production. Paredes. 1909. E. Ed.V. 1992.J. Environmental Protection Agency. K. Chim. (2002).economic technology assessment in view of sustainability. ECOS 2004 . et al. and Borbala Zelei. P. 2003. M. 25." Journal of Analytical and Applied Pyrolysis 77 (1): 35-40. Bangkok. V. Y.J. A development perspective for biomass-fuelled electricity generation technologies . P. (1998). Schenkel. Smith. Violette. Norlin. E. Antal. Faculty of Economics and Econometrics.. .J.. Formation of Charcoal from Biomass in a Sealed Reactor. (2006)... In Pyrolysis and Gasification of Biomass and Wastes. K.in Bridgwater. M.pdf. 304. Amsterdam. Mok. 20-24 May. M. Heidenstam. A. et al. Res. pp 511-526. UK. Chem. R. Ptasinski.. jr. Prins. Bertaux. "Torrefaction of wood: Part 2. "An evaluation of the mound kiln carbonization technique. Washington. Greenhouse Gases From Small-scale Combustion Devices in Developing Countries: CharcoalMaking Kilns in Thailand..v. K. Phys.. Varhegyi... Project GCP/RAS/173/EC. http://unfccc. 1162-1166 Padovani. Klason. ANNEX A ADDRESSES CARBONISATION EQUIPMENT Carbo Group b.J. Universiteit of Amsterdam. Die trockene Destillation der Cellulose. 1205. Untersuchungen zur Holzverkohlung. Prins. W. E... PhD thesis. M. Khummongkol.17th International Conference on Efficiency. in: Proceedings of the Workshop and Training on Forest Product Statistics. 32. EC-FAO Partnership Programme (2000–2002). Bedrijvenpark Twente 168 7602 KE ALMELO Netherlands 31 . P. G. Ind.. Ann. Costs.J.. S. 2002.FAO TCP 3101: Industrial charcoal production Henrich.. High-Pressure Synthesis Gasfrom Biomass. G." Energy. D. G. Dinjus. Simulation. 1999. F. Szabo. I. Mémoire sur les Charbons de Bois. and Environmental Impact of Energy on Process Systems 31 (15): 3458-3470. Analysis of products. The Measurement of Forest products. Tar-free. Eng.. R. Chem. P. Ptasinski.31. (Energi E2 . Siemons." Biomass and Bioenergy 14 (5-6): 505-516. M. (2006). et al.Denmark). Angew.int/files/methods _and_science/mitigation/application/pdf/eu_schultz. et al. Z. Modern biomass utilisation. 1853. Schultz. Optimization. "More efficient biomass gasification via torrefaction. EPA-600/R-99-109. CPL Press: Newbury. Pennise. com Lambiotte & Cie S.brand@carbo. Hajo Brandt I.Czech Republic Tel: +420 777 320 730 Tel: +420 573 391 118
[email protected]. des Aubépines B-1180 Brussels Belgium Tel.r.horvat@bj. Zdenko Jaki Belišće France ETS CALLEGARI CHRISTIAN Chez FAURE 17130 COURPIGNAC France Phone : +33 5 46 70 30 57 Fax : +33 5 46 49 71 39 Girondine de Carbonisation 33680 LACANAU France Phone : +33 5 56 03 56 30 Fax : +33 5 56 03 55 92 Navarre 32 32 . Svačića 15 HR-43280 Garešnica Tel: 043 / 44 50 21 Tel: 098 / 43 61 27 Tel: 043 / 53 14 94 Tel: 098 / 23 95 69 Fax: 043 / 53 14 94 mario. Mario Horvat KRIŽEVCI . Cvrčovice .b.cz/de_index.nl Mr.31.Pavel Svoboda EKOGRILL.55 E-mail : mail@lambiotte. Dr.Miroslav Macík Mr.holzkohle.volny.at Mr Johann Hochecker Czech Republic LESS a.cz www. Rajnochovice 276 768 71 .cz www. Ferde Kerna 8 HR-48260 Križevci Tel: 048 / 71 45 94 Fax: 048 / 71 45 94 Mr.dreveneuhli. : +32 2 374.PRODUKT d.o.T. Steinholz 23 A-3263 Randegg Tel: (07487) 8410
[email protected]. 18.o.44.at www. Via San Rocco 818 24033 Calusco d’Adda (Bg) Italy Tel : +39 035 791 800 Fax : +39 035 794 068 Email : info@itbiomass. s.l.cz/ekopor/ Croatia HORMAR d.H.o. P. Av.com CHARCOAL MANUFACTURE Austria Gebrüder Gruber Gesellschaft m.hr Mr.o.Karla Čurdy 119 CZ-27341 Brandýsek Tel: 313 564 732
[email protected] Mr Johann Gruber Johann Hochecker Kleindurlas 13 A-3074 Michelbach Tel: (02744) 8556
[email protected] Mr.65 Fax : +32 2 375. s.FAO TCP 3101: Industrial charcoal production Tel: +31546570462 Tel: +31653449505 Fax: +31546570604 Email: h.B.o. de Herr Heinrich Schmitz Rheinbraun Brennstoff GmbH.de
[email protected] TCP 3101: Industrial charcoal production Route Nationale 134 40420 GAREIN France Phone : +33 5 58 51 41 64 Fax : +33 5 58 51 63 44 Chemviron Carbon 58.
[email protected]@rwe. Tel. Avenue Wagram 75017 PARIS 17 France Phone : +33 8 00 80 28 52 Fax : +33 8 00 10 07 12 Ets Rousseau et Fils 24270 DUSSAC France Phone : +33 5 53 52 61 50 Fax : +33 5 53 52 28 16 Carbo France EURL 55290 MONTIERS SUR SAULX France Phone : +33 3 29 75 98 80 Fax : +33 3 29 75 88 83 Bordet Frères 21290 LEUGLAY France Phone : +33 3 80 81 81 69 Fax : +33 3 80 81 84 40 Usines Lambiotte Halted 3 Rue Auguste Lambiotte 58700 Premery tel : 0386377200 fax : 0386377225 Germany proFagus GmbH Uslarer Straße 30 -371 94 Bodenfelde Telefon +49 55 72 1 94 4-0 . Bedrijvenpark Twente 168 7602 KE ALMELO Netherlands Tel: +31546570462 Tel: +31653449505 Fax: +31546570604 Email: h. www.slzchemia.de Holzkohlewerk Lüneburg Plan 6 20095 Hamburg Director: Bernd Eichin Tel: +49-40-3233200 www. Hlavná 133 SK-98111 Hnúšťa Tel: 047/5422104 Tel: 047/5422165 Fax: 047/5422552 predajslzchemia@stonline. Hajo Brandt Slovakia SLZ CHÉMIA.r. D-50935 Köln.de Peter Diers Netherlands Carbo Group b.holzkohlewerk. Jaroslava Maceková EUROSLAT s.nl Mr.Fax +49 55 72 I 94 4-1 31 Heinrich Schmitz Hocksteiner Weg 62 D41189 Mönchengladbach Telefon: (02166) 958565
[email protected] Ing.koehlerei-jatznick.de
[email protected] Köhlerei Jatznick Rothemühler Chaussee 2 D-17309 Jatznick Tel.s.com.v. Still active? Skačany 189 SK-95853 Skačany Tel: 33 . a.de www.o.sk www. (0221) 480-0.schmitz-holzkohle.: (039741) 80892 koehlerei. o.B. Dušan Divko TENDER SLOVAKIA s.euroslat.FAO TCP 3101: Industrial charcoal production 038/7488136
[email protected]. Vihorlatská 1412 SK-06901 Snina Tel: 057/7750477 Tel: 0903/239635 Robert Petřík 34 .1 SK-01701 Považská Bystrica Tel: 042/4322960
[email protected] Ivan Hudec FINEKOS.o.r. Kragujevská 12SK-01001 Žilina Tel: 041/5622625 Ing.sk www.o.sk M. Podmostie č.sk www.paliva. s.s.r. Jana Turanová PALIVÁ spol.r.