Charcoal is known since ancient times. It was produced in many regions of the world, including, of course, Russia. Basically, they were regions rich in forest resources. There is evidence to suggest that the use of charcoal was known more than 7,000 years ago when it was used for copper smelting. It is known that in Egypt charcoal was used for iron melting and glass production 5000 years ago.
The most known methods of production of charcoal are pit and heap burning of coal. When using the heap method, the wood was laid so as to obtain a cone, the holes for air supply were left at the bottom. The pit method involved the use of a recess instead of the lateral part of the structure, and air was supplied through special wooden blows, which came out at the second end into the pits, the level of which is slightly below the level of the main pit. On top of the cone / pit covered with turf or wet clay. These methods gave a small percentage of the finished product, were long in time (sometimes a few weeks!) and required constant human control.
In Russia since the middle of the 19th century charcoal began to be produced in furnaces. Demidov dynasty made a significant contribution to the development of metallurgy and coal mining in the Urals. Demidov iron and foundry production began its development with charcoal. Only on charcoal is obtained benign malleable, ductile iron. Its special properties made it possible to create all the wonderful cast iron fences and many monuments of St. Petersburg. In the future, large forest chemical plants were built, which provided environmentally friendly production of charcoal and could provide an increasing demand for charcoal.
In the late 30s of the 20th century Professor of the timber industry V.N. Kozlov has developed a two-channel coal-burning furnace of continuous circulation type. Throughout the furnace in the floor are cast iron rails, which is moving trolleys with wood, and later with charcoal. Each channel has a drying chamber, the actual furnace, condensing and calorific setting. The drying chamber is located separately from the oven, but is on the same line with the latter. Two channels of the furnace are absolutely identical, so the description of only one channel is given further.
The drying chamber is a brick channel, separated from the receiving vestibule of the furnace at a distance of 8 m.at the beginning and end of the drying chamber there are iron gates with thermal insulation, rising by means of a winch with an electric motor. The chamber can accommodate 10 trolleys. The boot capacity of one trolley 10 m3 of timber, cut into lumps with a length of 200 mm, loaded in bulk. Heating and drying of wood are produced by the heat of waste combustion products from the furnace heat exchanger. For this purpose, combustion products are sucked in by the drying chamber fan and pumped into the mixing chamber through an underground gas pipeline. Drying time is about 20 hours.
After pyrolysis, the trolleys enter the cooling chamber, which is made of brick in the first 7.5 meters, the rest of the 22 m is made of sheet iron. Cooling of trolleys and coal occurs due to heat transfer outside through the walls, arch and under. Coal trolleys are cooled for 12 hours to reduce the chance of spontaneous combustion.
The whole process of carbonization, from the receipt of wood in the drying chamber and to complete cooling is about 40 hours. Loading wood into the oven. Cooling of the product. The finished charcoal
Now let’s look at some examples of modern furnaces
Now consider several options of modern ovens:
Dutch oven of the firm’s C.M.Technology BV with a front-load to produce a high quality coal. The manufacturer describes his furnace as
- This furnace does not require a building, only a flat and solid surface is required for its installation.
- The capacity is about 800-1000 tons / year depending on the time of production, the degree of coal calcination, wood species and moisture content of raw materials.
- For 1000 tons of coal, approximately 3200 tons of air-dried raw materials or wood waste from sawmills or a furniture factory are needed.
- On this furnace it is possible to make coal with a high percentage of non-volatile carbon. In this furnace coal of constant quality that is important for the industry and household consumers is made.
- Furnace continuous process, the most efficient use 24 hours a day, 7 days a week. It is possible to stop the process, but it will take additional time to start again.
- For the initial start-up, you will only need gas or diesel to heat the installation. When the operating temperature is reached, the furnace does not require additional fuel. The plants will be operated from pyrolysis gases coming from wood.
Installation of coal-burning pyrolysis “Buran-300”.
The equipment of the Buran series belongs to the type of continuous, non-retort, with full afterburning of pyrolysis gases, installations.
Capacity: 10 tons per day, up to 300 tons per month of hard-hardwood (birch, beech, hornbeam, oak). 8.6 tons per day, up to 260 tons per month from aspen, alder (including sawmill waste). 7.2 tons per day, up to 220 tons per month of pine, spruce (including sawmill waste).
- all pyrolysis gases are completely burned in the furnace.
- Number of staff two people (without preparation of raw materials).
- The content of solid carbon in the finished product is more than 88%.
- The technological cycle takes 4 hours.
Photos from the site www.tdi-ural.com
One of the best modern retort charcoal kilns installations is Ekolon 5.2. The peculiarity of the furnace is that the liquid and gaseous products of thermal decomposition are not removed, but are sent to the furnace and burned there. The heat from their combustion is used for further operation of the furnace. Due to this, the furnace furnace in the summer does not need additional fuel, and in winter consumes limited wood waste. The only product is charcoal. The operating parameters can achieve different degrees of coal calcination in accordance with the customer’s requirements. Emissions to the environment are environmentally friendly and do not differ from the smoke of conventional wood-burning stoves. According to the manufacturer, this coal-burning plant produces about 5 tons of finished coal per day
Another example of a great retort charcoal kiln — a furnace from “Synergy Dream ” MODEСO 4-60. This furnace consists of 2 pyrolysis blocks, each having two stationary retorts. This furnace works only with an automatic control system, which ensures the safety of work and the minimum number of workers serving the installation. Feature furnace system MODECO 4-60 is the variety allowing you to choose the stove to suit your needs. So the basic model of the MODECO 4-60 works fine with lumpy coal with a moisture content up to 25%.
Model MODECO 4-60 PS is equipped with a pre-drying complex, with which you can work with wood of natural moisture, that is, about 60%. The complex of pre-drying reduces the moisture content in the wood by 30-40%, which allows to obtain higher quality charcoal with less labor.
MODESO 4-60 CS is specially designed for coconut shell burning, which is very useful for regions where the main source of raw materials is coconut.
MODECO 4-60 S is a furnace designed to burn small-sized raw materials such as wood chips, small-scale waste from wood-processing industries, walnut shells, seeds of fruit trees, etc. The design of the retorts is such that it can effectively burn wood in a fraction of 10 to 40 mm.
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