LV11333B - Method and device for production of charcoal - Google Patents

Abstract

This invention pertains to charcoal recovery by means of a dry distillation technique in retorts by a gradual increase of temperature up to 430-450 degrees C. All stages of the process and necessary equipment/units are stipulated so that to realize an energy-autonomous and environmentally friendly process flow, control and management, the equipment includes a single furnace and one to four retorts.

Description

Method and equipment for the production of charcoal

Description of the Invention

BACKGROUND OF THE INVENTION The invention relates to the chemical technology of fuel and can be used in the forest chemistry and fuel extraction industries, in particular in the field of dry wood by means of retorting.

Techniques for obtaining several charcoal are known (1-5), including in retorts and cassettes. There is a great variety of equipment for their implementation. Among these is LV patent 10631/6 / which describes a method for obtaining charcoal and a retort furnace for implementing this method, which have been selected as a prototype.

According to the prototype, the retorts are placed directly in a furnace designed in the form of a heat-insulated shaft and fitted with a lid. Underneath, there is a support for openings in the top of the stove. Sealing lids, such as sand-filled pockets, shall be provided at the joints between the cover and the housing and / or the grooves and the horizontal support. A gas manifold is formed between the lid and the horizontal support to transfer gaseous products of wood pyrolysis to the furnace furnace, thereby ensuring the heating of the retorts to the end of the charcoal formation. The production of charcoal by this method, when retorting is inserted directly into the furnace, results in faster charcoal burning and simpler process implementation, but the overall quality of charcoal is lower than that of the charcoal obtained by dry distillation at lower temperatures. In addition, by this method and equipment, by-products of dry distillation of wood, such as wood tar, vinegar water, wood alcohol, acetone and, in the case of conifers, turpentine and rosin, are completely eliminated, since all the condensate is evaporated, returned to the furnace. The higher the retort temperature, the less coal and wood tar we get, but the more fuel we get. Slowly increasing the temperature, we produce ~ 25 m ^{3 of} fuel gas per 100 kg of wood, while raising the temperature rapidly we get 110-120 m ³ . Thus, if more wood is needed, but less charcoal is needed, it is advisable to use the method and equipment described in the prototype for charcoal production. It is common knowledge that the range of wood distillation products is highly dependent on the type and temperature of wood heating. The higher the temperature, the more the retorts become more deformed and burned out during the process, which results in a very long lifetime of the retorts located on both sides of the fire area. The duration of the technological process in retorts depends on the intensity of the firing and is determined by the flue gas color, using the skills of the firefighter, as the retorts do not include temperature gauges, which results in charcoal burning and roaring, though good in appearance.

The abovementioned by-products of the charcoal production, which can be obtained by dry distillation of wood at retorting at moderate temperatures, may give the producer additional output and profit. Even at lower temperatures, the resulting amount of fuel gas is sufficient for production to maintain the process and it is not economically viable to use valuable tar water as fuel. Even if there is a small need for extra fuel, it is economically more profitable to get this small amount by burning woodworking waste - firewood, etc.

The object of the invention is to eliminate the disadvantages of the process described above, at the same time increasing its economic efficiency and ensuring its energy autonomy and ecological purity.

Description of drawings

FIG. 1 Proposed charcoal production scheme

Fig.2 Schematic of the vapor-gas discharge from the retort and the construction of the retort cover

Fig.3 Proposed charcoal production scheme with one insert and four retorts

Fig.4 One possible embodiment of the furnace is a cross-section A-A

Fig. 5 The furnace shown in fig. 4, section B-B

Fig.6 Nozzle-burner for returning and gaseous wood products from the gas distillation furnace

The following terms are used:

- raw material (wood) basket - container, 2 - retort, 3 - central furnace, 4 - cooling container, 5 - chimney, 6 - retort, 7 gas pipe, 8 - sand can, 9 - top cover, 10 - retorts wall, 11 sand layer, 12 - ring seal, 13 - steam-gas outlet, 14 water seal, 15 - vertical movable seal, 16 - rotary manifold, 17 - steam outlet, 18 - stationary seal, 19 - smoke on chimney - external wall of the building.

Summary of the Invention

A schematic diagram of the proposed charcoal production method and apparatus is shown in FIG. 1. It provides for the vertical retort to be heated from the outside by raising the temperature to 430 ° -450 ° C. In addition to heating the retort without process fuel, the vapors and gases of the products of the thermal destruction of wood are additionally used, returning them to the furnace through the gas nozzle-burner continuously throughout the process.

The process is offered in 5 stages.

Step one. At the start of the retort, the steam outlet is opened and held open until almost all physically bound water has been removed from the process firewood. In order to ensure a better discharge of water vapor into the atmosphere, a vapor collection pipe is connected to a chimney about 10 meters long. When the retort temperature reaches about 130 ° -150 ° C, it can be considered that the capillary and hydroscopic water is completely removed from the technological firewood.

Before any mechanically bonded water from the retorted firewood has been discharged and the exhaust gas has started to escape, the vapor exhaust pipe is closed. Volatile gases begin to form and, along with the last water vapor, begin to flow into the furnace as fuel.

For the control of flowing vapor-gases, it is proposed to install a burner, approximately 5 mm in diameter (with tap), in the gas line, through which the flow of gas from the retort is checked in an attempt to ignite it. In case of ignition it is

- The vapor drain pipe is closed and the gas flows to the furnace as fuel. The process is energetically autonomous.

The duration of the distillation process retort with external heating and retort volume for 4-5 m ³ dry and semi-dry firewood (21-33%) is about 20 hours, while the actual process lasts up to 24 hours for freshly prepared, non-dried firewood. Therefore, in all subsequent calculations (also during the summer period) the duration of the technological mode is assumed to be 24 hours. Undoubtedly, this duration of wood distillation will be reduced if the above mentioned disadvantages are eliminated. This in turn will improve economic performance. Provision should be made for the firewood to be prepared in good time for a reserve of at least 3-6 months. During this time, the wood dries to about 30% moisture.

When wood is heated without air at 102 ° -105 ° C, it dries. When the tree is heated to 130 ° C, it dries completely. All organic materials, as the temperature increases, interfere with the conversion of simple but durable compounds such as water, carbon, CO and CO ₂ .

Phase Two. At 150 ° -230 ° C - brown spots appear on the wood and the wood particles start to char. When wood is heated to 170 ° C, it loses hydroscopic water. In the second period, the release of wood distillation products begins. Only non-thickening gases and tar are released during this period.

Stage Three. At 230 ° -280 ° C, light onset of charcoal is formed, it has a high adsorption property and so-called pyrophoric carbon is formed. Carbon begins to intensively bond with oxygen during this period to form carbon dioxide. The temperature during the retort increases steadily but not rapidly during this period.

Phase Four. At 280 ° C to 330 ° C carbon formation occurs. At 280 ° C a significant amount of gas is released. The rapid decomposition of wood with the release of large gaseous products occurs even without further heating. During this period, gaseous hydrocarbons are mainly emitted: CH4, C2H4, C2H2, CO, CO2. There is rapid decomposition of wood and release of large amounts of heat. At this temperature, hydrogen, methane, ethane, as well as more acetic acid, methyl alcohol (wood alcohol) and tar are released, but carbon dioxide and carbon monoxide are released. At the exothermic reaction, the temperature in the pyrolysis retort increases rapidly to 330 ° C.

Step Five. At 430 ° C, the charcoal formation process ends. At 430 ° C, wood decomposes technically because up to this temperature has already released about 81% of volatile compounds. Depending on the final temperature (430θ-450θ C), it takes about 1-2 hours for the temperature to rise in diameter and height to retort.

-7Table 1

Charcoal formation process

Stage Temperature, ° C Duration, h Characteristics The first 50-150 6th The wood dries completely The second 150-230 - 5 The wood starts to charcoal Third 230-280 - 5 Light charcoal glow Fourth 280-330 - 3 Coal formation occurs Fifth 450-470 ~ 5 The carbon formation process ends Together 450-470 -24 Produces quality charcoal

The duration (in hours) of the charcoal formation process is calculated by averaging 30 charcoal production cycles (control numbers).

The duration of the individual stages of the charcoal formation process depends on: 1) the initial moisture content of the wood in the wood, 2) the species of wood, 3) the retort cooling rate during retrieval of charcoal from the retort factors.

It is proposed to remove the condensed liquid from the process, hereafter referred to as tar water, from the system by equipping the gas condensate line with a liquid fraction drain tap and place it in a settling vessel where it decomposes into two main fractions, wood tar and vinegar.

In order to improve the organization of the work, to reduce the time wastage during retort filling, it is proposed to design the retort cover structure as shown in FIG. 2:

- cover ring (diameter 1 m) made of flat iron 50 x 10 mm (or 40 x 8 mm);

- the ring is clad on both sides with a sheet of 1.5-1.8 mm thick and filled with heat-insulating material inside;

- a seal made around the circumference of the ring, eg 3 x 50 (70) mm welded to the bottom edge;

- at the upper flange of the retort the wedges of the retort were replaced by a U-shaped ring filled with fine gravel;

- a water-tight seal of average construction of not more than 250 mm in the center of the cover.

By placing the retort cover on a U-shaped seal, its sharp edge dips into the gravel filler and completely seals the gas release into the atmosphere along the edge of the cover, ensuring ecological cleanliness and high productivity.

In order to vent the outgoing steam from the retort to the atmosphere, it is proposed to install a special vapor-gas receiver (Fig. 2), which is connected to an additional mounted 10-meter high chimney (calculated from the top of the retort). The inside diameter of the chimney is 180-200 mm.

This gas-vapor trap is also used during the emptying of the retort from the coal to achieve the upward movement of the gas retorted during the retorting process.

In this way, the remaining gas mixture with air is retorted into the atmosphere at a height of about 15-16 meters.

The operating principle and tasks of the proposed steam-gas discharge system (Fig. 2) are as follows:

1. After the process wood is filled into the retort 2, the vapor gas outlet duct 13 is completely sealed with a stationary seal 18 for 30 minutes to interrupt the slight pre-combustion of the feedstock in the retort and to accelerate the water evaporation process from the retorted wood.

2. After 30 minutes, the stationary seal is replaced with a vertically movable seal 15 connected to a rotary manifold 16 and further to a steam outlet chimney 17.

3. As a result of the dry distillation of the wood, water vapor is released from the logging 2 retorted into the atmosphere and discharged into the atmosphere through the chimney 17. This prevents the possible release of steam into the production space.

4. When the temperature gauge (thermometer, thermocouple) at the top of the retort shows 160 ° -170 ° C, the vapor-gas discharge system is disconnected as the water vapor has ceased. The steam-gas outlet is sealed with a stationary seal 18. The first combustion gases begin to flow to the furnace as fuel.

5. When the retort is prepared for the release of the charcoal in the coal cooling container 4, the retort is connected to a vapor-gas discharge system. Opening the retort lower hatch and releasing the charcoal creates an upward air-gas draft in the retort.

In order to reduce the duration of the technological cycle, it is offered:

1) create a smoke section around the retort depending on the retort diameter and height;

2) use ceramics (bricks, tiles) but not metal to create a smoke spiral;

3) latches, such as throttle bolts, shall be fitted both before the retort (used mainly for retort repair) and behind the retort (used to control the technological mode);

4) retort the retorts with a 500-600 mm thick masonry layer; possible variants:

(a) complete masonry with well-dried, but not burnt, bricks;

(b) the masonry is made up of three layers, the inner and outer layers of semi-brick masonry and the middle part of which is filled with a lean clay dressing;

(c) The masonry unit shall be made of perforated bricks by pre-casting the holes in the bricks with a thick mortar.

For the chimney not only to function as a smoke collector and extractor, but also to replace a smoke fan, its optimum dimensions are as follows:

- for the operation of one retort, the chimney has an inside diameter of 260-280 mm and a length of 22 meters from the upper edge of the retort, the flue;

- for the operation of two retorts, the chimney has an inside diameter of 300 to 320 mm and a length of 24 meters from the top of the retort, a flue.

Furnace wall masonry as well as smoke duct on retort should be 500-600 mm thick, including inner layer of semi-brick made of fireproof bricks ~ 6 ~

One furnace can provide the simultaneous normal operation of four retorts (fig.3).

Example of implementation of the invention

Raw material - dry birch and alder wood, cut into 15-17 cm cubes and chopped into pieces of 6 cm (larger cubes are slower to distill). The raw material is cut using a conventional circular saw blade or a circular saw blade with a mechanical pusher.

It is not advisable to use a wood saw splitter with a hydraulic wood pusher because of its low productivity for small wood splitting.

Subsequently, the feedstock is filled into a wood basket-container 1, for example by means of a conveyor, and the retort 2 is emptied through a retractor through the upper port of the retort. See point. The apparatus for carrying out the process is described in Claim 8 of the formula of the invention. The furnace used is shown in fig. 4 and 5, and the gas burner retorting to recover and burn the resulting gas in the furnace is shown in figs. 6. The implemented technological process is autonomous and ecologically clean.

Central furnace outside dimensions per retort, mm:

1) Length - 2800-3250, 2) Width - 1600-2100, 3) Height - 2200-2600. Furnace dimensions depend on the number of retorts.

Retort dimensions (for metal part), mm:

1) overall length 3000-3600

2) cylindrical length 2200-2650,

3) internal diameter * 1700-2200,

4) length of the lower cone - 350-450

5) firewood filling and charcoal discharge hatch diameter - 1000-1150.

The minimum or maximum retort length or cylinder diameter depends on their relationship.

When the charcoal formation process at 450 ° -470 ° C retort is completed and the temperature equalization time (** 1h) is observed, a coal cooling container is run underneath the retort, 30-40 liters of water are poured into it, the retort 2 bottom hatch and air free quickly pour into the cooling container. Immediately seal the container with a lid. Pour water into the lid channel to form a seal.

The charcoal must remain in the cooling container until its temperature has dropped to 50 ° C. The removal of the hotter coal from the cooling container results in the coal self - igniting.

If the temperature of the coal in the cooling container does not exceed 50 ° C, the container may be emptied.

After the retort has been emptied, it is immediately filled with raw material for starting a new technological cycle. As the retort's special masonry has accumulated a large amount of heat during the previous technological cycle,

-7 After the retort is filled and the lid of the retort sealed, the process immediately begins with the intensive release of water vapor.

It is expedient to fractionate the condensed effluent, which consists mainly of tar, vinegar, wood alcohol and acetone, and to sell it separately as raw materials. The condensed product obtained by the process, when mixed with sawdust, can also be used as an additional fuel provided that it is completely combusted, resulting in only water and carbon dioxide.

The condensed composition obtained during the process also depends on the degree of thermal insulation of the vapor-gas leaks.

Sources of information

1. DE - Patent Applications: P 2401810, P2523968.3 and P2953663.8; SKI C10B53 / 02.

2. USSR a.a. 597706, 610854, 661000, 865890, 947177, 994548, 1154305, 1171506, 1337394, 1399727, 1446139, 1504244, 1624015, 1663009, 1663010, 1808003, 1826983 and 1826984; SKI C10B53 / 02.

3. Patent applications: PCT / AU84 / 00208, PCT / US81 / 01615, PCT / FR79 / 00006, PCT / FR79 / 00037, PCT / FR82 / 00187 and PCT / FR89 / 00436; SKI C10B53 / 02.

4. Patent applications: EP 93305 402.5 and EP 92307788.7; SKI C10B53 / 02.

5. JP - Patent Applications: 56-98322, 56-109744, 57-187947, 59-145282, 59147080, 58-76002, 58-76993, 60-38492, 61-209293, 61-170901, 63156884, 62-24714 , 62-24715, 62-328872, 63-113859, 64-344289 and 64144093; SKI C10B53 / 02.

6. Patent LV 10631 (prototype) Charcoal extraction process and retort furnace process; SKI C10B47 / 00.

Claims (14)

Formula of the Invention 1. A method of extracting charcoal which includes: pre-drying, sorting, slicing / shredding and loading of the raw material into a stationary or mobile intermediate container, - Emptying the intermediate container - retransfer, sealing and sealing the raw material, - heating the retort from the outside by gradually raising the temperature (t °) to 430 ° -450θ C and using for this purpose (in addition to process fuel) the vapors and gases of the wood thermal destruction products, returning them to the furnace and incineration, - unloading of the charcoal from the retort in a closed air-cooled container and cooling to 50 ° C, - the removal of condensed water, mainly consisting of tar, vinegar, wood alcohol and acetone, from the system (retort pipelines) by one or more processes, characterized in that: - the heat treatment of the starting material during retorting is carried out in 5 steps: in the first step, it is completely free of hygroscopic non-bound water at t ° = 50 - 130-150 ° C; in the second stage, it is mainly free of hygroscopic water and partially charred (t ° = 150-230 ° C, duration up to 5 h); in the third stage, it is partially superseded, producing mainly carbonic acid (t ° = 230-280 ° C, duration up to 5 h); in the fourth stage, it is rapidly distilled off to form a large quantity of gaseous products (t ° = 280 to 330 ° C, duration up to 3 h); in a fifth step, equalization of the carbon formation process over the entire retort volume (t ° = 330 4-450-470 ° C, duration - up to 5 h, including temperature equalization duration over the entire retort volume 1-2 h); - in the first stage of heat treatment of the feedstock, water vapor from the retort is discharged through the vapor discharge system in the top lid, keeping the steam outlet open until the required moisture and t ° of the feedstock are achieved; - in the second to fifth stages of heat treatment of the raw material, the vapor discharge system is kept closed, but the gaseous products formed during the process are introduced into the furnace via a gas line through a nozzle burner and burned; - at all stages of the heat treatment of the feedstock, the process is controlled by measuring the temperature inside the retort at least at one point, preferably at several points, more preferably by a sample of the feedstock and by controlling the flammability of the vapor the addition of a special burner to ignite the exhaust gas; - the charcoal extraction process described above is controlled by providing combustion and flue gas parameters such as an air inlet duct opening in the furnace, which in turn provides the necessary treatment of the wood by retorting. 2. The method of claim 1, wherein said method is different. that the retorts are sealed by placing the top lid loosely on the retort hatch without any additional fastening or sealing, such as clay or the like. A method according to any one of the preceding claims, characterized in that the process is controlled; in the first stage, the steam-air outlet duct is closed for 30 minutes by means of a stationary seal and then by means of a vertical movable seal, which is connected to a rotary manifold and further to a chimney (fig-2); - in the second + fifth step, by simultaneously or alternately adjusting the position of the shutters in the furnace and the heat carrier - the distillation of wood in the gaseous product circulation system. A process according to any one of the preceding claims, characterized in that the condensed effluent is mixed with sawdust and used, for example, in the form of briquettes as an additional fuel for the process. 5. A method as claimed in any preceding claim, wherein a multichannel device is used to control / record and control the process, such as a multichannel potentiometer that registers / outputs a series of data in which each member retorts and processes the process at a fixed instant. pipelines. Method according to any one of the preceding claims, characterized in that the process temperature is controlled by means of thermocouples introduced into the retort through a lid by means of a special element. 7. A process according to any preceding claim, wherein the process is energetically autonomous and ecologically clean, providing condensed drainage, collection and / or eco-friendly recycling, and returning the resulting process gas to the furnace via a closed gas line and complete combustion, as well as control of the exhaust through the chimney and, if necessary, further treatment. 8. A charcoal production plant according to the above-described process comprising; - heat generating unit - furnace, - at least one vertical hermetically sealed retort formed by double-walled smoke-filled walls, the outer wall of which is covered with heat insulation, with openings for loading / unloading raw materials and openings for venting and condensing gas, - a system for removing water vapor and heat carrier gas from the retort into the atmosphere, - a system for ensuring the circulation of gaseous products of heat carrier and wood distillate from the retort back to the heat unit equipped with a condensed collector; - process control / recording and control system, - Auxiliary equipment for loading of raw material and for unloading and cooling of charcoal (containers, lifters, etc.), characterized in that: - the retort cover (fig. 2) is made of a flat iron ring which is clad on both sides and covered with heat insulating material; a seal fitted on the circumference of the ring, for example welded polished iron; the retractor's upper flap wedge is formed as a U-profile ring, which is filled with fine gravel, and a water seal is formed in the middle of the lid; a vapor-gas receiver with a vertical movable seal, a rotatable manifold and an outlet chimney; ~ zc ~ - Ceramic materials, such as bricks, tiles, used for the installation of smoke between the retort inner and outer walls: - Chimneys fitted with latches such as butterfly valves, both before and after the exit of the retort (for regulation of the technological mode): - retort thermal insulation is made of masonry made of well-dried but unburned bricks in a layer of 500-600 mm thickness, with the inner layer of semi-bricks made of refractory bricks. 9. An apparatus according to claim 8, characterized in that. that the thermal insulation of the retort is made up of three layers - the inner and outer layers like a half-brick wall and the interlayer filled with a lean clay dress. The apparatus according to claim 8, characterized by. that the retort heat insulation is made of masonry made of perforated bricks by pre-casting the holes in the bricks with a thick clay mortar. The apparatus of any preceding claim. that up to four retorts are clutched with one insert. 12. An apparatus according to claim 11, characterized in that. that the inside diameter and height of the chimney relative to the level of the retort cover are selected depending on the number of retorts. Apparatus according to any preceding claim. that the gaseous product circulation system for collecting the liquid fraction of the wood distillation is equipped with a tap for condensed discharge. Device according to any one of the preceding claims, characterized in that all the assembling units / equipment and fittings ensure the implementation of an energetically autonomous and ecologically clean process according to any one of the first to seventh claims.