INDUSTRIAL PROCESS USING A FORCED-EXHAUST METAL FURNACE AND MECHANISMS DEVELOPED FOR SIMULTANEOUSLY PRODUCING COAL, FUEL GAS, PYROLIGNEOUS EXTRACT AND TAR

Abstract

This patent of invention is related to a process and a furnace developed for production of charcoal with recovery of gases, tar and pyroligneous extract. The unity system is composed by a metallic furnace, a loading platform, a carbonization platform and unloading platform. For continuous generation of gases, the process operates with multiple carbonization platforms and one or more furnaces for carbonization platform. The furnace is provided with air inputs in strategic side points and mechanism for relieving pressure. The carbonization system is composed by an exhauster, special pipes for conducting the gases, and devices for the recovery of condensable. The gases generated in the process are directed to a burner, a gasifier or directly in a boiler to generate thermal and/or electrical energy. The technology presents, exclusively, a gravimetric yield in fuel gas superior to 60% and a productivity on charcoal above 800 kg/h, so that each operating cycle of the furnace takes less than 5 hours. The coal is discharged hot, after carbonization and loaded on wooden billets immediately after unloading. The process combines technical, economic, operational, and environmentally viable solutions.

Claims

1. Industrial process using metallic furnace with forced exhaust and mechanisms developed for concomitant production of coal, fuel gas, pyroligneous extract and tar, characterized by having a carbonization system comprising a movable support base, which comprises a metal ring guides for furnace positioning, truncated cone and weighing system and mechanisms for locking the furnace on the ring; condensable recovery equipment, which comprises an expansion box with independent outlets for the gases and condensable, filter and storage tank; safety device for pressure relief, which comprises a hinged door and chimney; exhauster and gases and vapors conducting ducts.

2. Industrial process using metallic furnace with forced exhaust and mechanisms developed for concomitant production of coal, fuel gas, pyroligneous extract and tar, according to claim 1, characterized by a movable support base, which comprises a cylindrical ring of diameter equal to the largest diameter of the support structure, with positioning guides made of parallel plates that form a channel through which a guide plate attached to furnace runs, until the furnace completely supports on the movable base.

3. Industrial process using metallic furnace with forced exhaust and mechanisms developed for concomitant production of coal, fuel gas, pyroligneous extract and tar, according to claim 1, characterized by a movable support base provided with a industrial weighing system with loading cells articulated to absorb any lateral shift caused by collision between the furnace and the guides, between the furnace and movable support base.

4. Industrial process using metallic furnace with forced exhaust and mechanisms developed for concomitant production of coal, fuel gas, pyroligneous extract and tar, according to claim 1, characterized by an expansion box of sufficient diameter to reduce the speed to 50% of speed in the gas conducting duct; having two flow outputs with the first located at the base of the box and is provided with a filter that allows the flow only of the condensable to a storage tank and the second outlet located at the side of the expansion box enables output of the gases and vapor and mist still dispersed in the gas flow through the duct, sized not to have flow velocity above 16 m/s.

5. Industrial process using metallic furnace with forced exhaust and mechanisms developed for concomitant production of coal, fuel gas, pyroligneous extract and tar, according to claim 1, characterized by a connection between movable support base and the expansion box carried out by two concentric tubes wherein the smaller diameter tube is physically connected to the truncated cone reversed of the movable support base and the largest diameter tube remains connected to the expansion box wrapped by a flexible junction made of glass fiber fabric coated with a plastic film having one end attached by clamps to the inverted truncated cone in the upper position and the other end attached to the larger tube at the bottom.

6. Industrial process using metallic furnace with forced exhaust and mechanisms developed for concomitant production of coal, fuel gas, pyroligneous extract and tar, according to claim 1, characterized by it containing a safety device for pressure relief at the end of the pipe comprised by a flat surface, which is kept closed by using only the own weight of this surface constructed in metal plate called cover which rises in case of pressure in the ducts that lead the gas to the exhauster and chimney for conducting gases released during the pressure relief.

7. Industrial process using metallic furnace with forced exhaust and mechanisms developed for concomitant production of coal, fuel gas, pyroligneous extract and tar, characterized by a base for unloading comprised by a platform that has a truncated cone with the largest diameter compatible with the diameter of the largest bearing structure (DB) and smaller diameter compatible with the discharge valve.

8. Industrial process using metallic furnace with forced exhaust and mechanisms developed for concomitant production of coal, fuel gas, pyroligneous extract and tar, according to claim 7, characterized by for disposing or relying on a mobile cylindrical container with capacity between 24 and 32 m.sup.3 of charcoal, constructed of metal plate, prepared to receive the burning coal unloaded by the unloading platform, having 3 to 5 water spray nozzles, with flow rate ranging between 5 and 20 L/min, which are positioned to cool the burning coal during unloading and a central nozzle, positioned in the center of the load.

9. Industrial process using metallic furnace with forced exhaust and mechanisms developed for concomitant production of coal, fuel gas, pyroligneous extract and tar, according to claim 7, characterized by for disposing or relying on a cylindrical container, provided with an upper cover, sealed by hydric seal; said container after receiving the coal keeps isolated, without air intake, for cooling, with time of less than 15 hours, to achieve temperatures below 60 C. throughout all volume.

Description

DESCRIPTION OF THE DRAWINGS

[0058] The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

[0059] FIG. 1 shows sectional views of a furnace for the industrial production of charcoal and the recovery of generated gases;

[0060] FIG. 2 shows cross-sectional views of the furnace of FIG. 1 illustrating the opening and closing of the furnace during the loading and unloading of the furnace;

[0061] FIG. 3 is a schematic view of the furnace shown in FIG. 1 including the equipment used for gas recovery; and

[0062] FIG. 4 is a cross-sectional view of the furnace illustrating the unloading of the furnace.

DESCRIPTION OF THE INVENTION

[0063] The metal container of the industrial furnace (1) for the production of charcoal has its inside volume divided virtually into three parts according to FIG. 1: Top (R1), core (R2) and lower frustum (R3). There are no physical barriers between regions; the division listed here is done only to simplify the description of the various components of the proposed solution.

[0064] The top region (R1), located at the top of the furnace may be in cone shape or torresferic. This region may be partially divided or completely separated from the central cylinder, as shown in FIG. 2, assuming the cover function (2) to the biomass charging hole inside the furnace (3). Moreover, its truncated cone-shaped or torresferic shape allows the creation of relief mechanisms to control the internal pressure of the process (4). This pressure relief mechanism is defined as a relief hole, preferably circular in the surface of the top region sealed by a mobile relief cover, compatible with the hole that vertically moves upwards when the internal pressure rises beyond the expected and returns to the seat of the hole when regularized the internal pressure. The hole may be positioned anywhere on the top surface of the region, but it should preferably be concentric with the diameter close to the furnace. The relief cap should have an area and weight compatible with the furnace with the raw material and the process, which to this invention corresponds to an area ranging between 0.25 and 0.45 m2 and weight between 30 and 55 kg. The initial dimensioning of valves for burst relief had a base on the standard NFPA68/2007, but due to limited applicability of this standard to the industrial furnace for charcoal production, the final values for area and weight was due to the development of own mathematical models associated to blast tests conducted in situ in the furnace. The seal (5) between the cover and the relief hole must be made by a material resistant to temperatures up to 95 C., soft to absorb impacts and promote the sealing, since the pressure necessary to ensure sealing process will be function only of cover weight. The mobile relief cap has its vertical travel limited by a series of tabs, preferably three equidistant or hinged connecting the pressure relief hole cap (4) to the top region (R1).

[0065] In its optimal configuration, the top region has the largest diameter, in the case of frusto-conical shape equal to the diameter of the central cylinder region, with a frustoconical inclination to the vertical must have an angle (A1) between 8 and 25. The region is internally insulated with ceramic fiber blanket (6) and this is isolated from contact with the raw material inside the furnace by a thin plate (thickness 1.5 mm) of stainless steel (7). This plate also prevents contact of the insulating blanket with vapors and tar dispersed in the internal atmosphere of the furnace. The top region (R1) is fixed to the central cylinder region via specific mechanisms positioned near the larger diameter top. These mechanisms are pivot pins (8) secured to the central cylinder region which fit over guides (9) attached to the top region (R1). The joint is sealed using special seals for high temperature (10). The pressure required to ensure the seal is made possible by threads presented on pins and nuts placed on the guides.

[0066] The called central cylinder region (R2), shown in FIG. 1 corresponds to the main area of process control. The central cylinder preferably has diameter (D) of 3500 mm and height (H) of 4800 mm. Its lateral surface has a series of holes, shown schematically in FIG. 2, provided with flow control mechanisms (11) (control valves). These valves are distributed as follows: four (4) columns of valves equally spaced along the perimeter of the cross section and each column there are valves distributed in 7 positions along the furnace height. There are a total of 28 holes (11) through which they can inject gas into the furnace or use as a leak in case of overpressure during the conversion of biomass into charcoal. These 28 valves (11) are responsible for providing atmospheric oxygen to the perimeter area of the furnace. Furthermore there were placed four (4) tubes which connect the furnace wall to its inside in a diameter close to the center. These four tubes are also equipped with flow control mechanisms. These mechanisms are ball valves, with ball in stainless steel and focus in material for temperature to 150 C. With respect to height, the tubes are positioned at an intermediate height of the holes located on the lateral wall, with two tubes per level.

[0067] The height of each of the valves is determined according to the study of the furnace temperature profile. In this study, it was evaluated the speed when the temperature isotherm at 200 C. value moves along the furnace height. The value of 200 C. is said by studies in the area as the temperature at which finishes the drying of wood, i.e., from this temperature begins to roast, followed by carbonization process itself. The studies developed for the preparation of the proposed solution demonstrated that the step of greater length of the conversion process is the drying of the wood linking water, we sought to study the isotherm behavior at 200 C. in the furnace and the means to promote the acceleration of its movement, thus accelerating the drying process. So, it was proceed with analysis of the isotherm velocity displacement at 200 C. due to the positioning of the holes. The data obtained from laboratory tests have shown that the speed with which this isotherm advances in the furnace bed is reduced gradually from the furnace ignition point forward. Only there is the increase in speed of propagation when new approach occurs from an oxygen entry point. Given the typical behavior of the speed of isotherm with value of 200 C., it was possible to affirm and optimize what would be the recommended minimum distances between atmospheric gas inlet holes. The positioning of the holes along the height of the central cylinder region to its optimum configuration can be seen schematically in FIG. 1, according to the detailed study should be distributed as follows: four holes with a 2 diameter in the position (H1) between 5% and 7% of the total height of the cylindrical region measured from the base of the central cylinder, 4 holes with a diameter of 2 at the position (H2) between 18% and 26% of the total height of the cylindrical region measured from the base of the central cylinder, 4 holes with a diameter of 2 at the position (H3) between 30% and 38% of the total height of the cylindrical region measured from the base of the central cylinder, 4 holes with a diameter of 2 at the position (H4) between 60% and 54% of the total height of the cylindrical region measured from the base of the central cylinder, 4 holes with a diameter of 2 at the position (H5) between 62% and 68% of the total height of the cylindrical region measured from the base of the central cylinder, 4 holes with a diameter of 2 in position (H6) between 78% and 84% of the total height of the cylindrical region measured from the base of the central cylinder, four holes with a 2 diameter in the position (H7) between 94% and 98% of the total height of the cylindrical region measured from the base of the central cylinder; all holes are equipped with valves for flow control. The minimum distance between tubes positioned between the holes on the cylinder side is 26% of the total height of the cylindrical region measured from the base of the central cylinder, it is recommended the use of these tubes between the levels located in the furnace base, because at this part the conducting of carbonization process becomes more critical.

[0068] In FIG. 2, close to each of holes and tubes, one sensor monitors the temperature at the side (12) and inside the furnace (12a) with the aim of providing an accurate indication about the status or progress of the process carbonization and ensure that the safety limits for proper furnace operation are not exceeded. These devices for measuring temperature may be K-type thermocouples that are embedded in thermowells which house the sensor and electrical connections of tar vapors and mists present inside the furnace. For purposes of control, beyond the side thermocouples, a series of temperature sensors is installed inside the furnace (12a) near the central region, for a better monitoring of the procedure.

[0069] The region of the central cylinder (R2) is internally coated with several layers of materials which thermally insulate the metallic housing. The industrial furnace for charcoal production works with process temperatures of around 400 C., but in the region of the holes this temperature can reach peaks of up to 1100 C. This occurs due to the entry of external atmosphere oxygen from the interior furnace, which in contact with the fuel gas and ignition source form a flame like a blow torch. Technically there are materials on the market that can withstand the high temperatures described in this report, but the carbonization process has aggravations that makes impossible the isolated use of these materials. During carbonization are released in addition to the condensable and non-condensable gases, water vapor, tar, pyrolignous extract and volatile compounds present in the ash. The tar inside the furnace is in the form of a fine mist, which would pervade and damage certain types of insulating blankets, as well as the alkalis present in the ash. Furthermore, most of the refractory material presents a percentage of total passageway pore, i.e., they are pores that connect hot face to the cold face allowing the passage of tar, which could damage the outer wall of the furnace. Both the tar, as pyrolignous extract have in their composition a portion of acetic acid which reflect the corrosive nature of the internal atmosphere. Some refractories are incompatible with acidic atmospheres or water vapor. The material to be loaded by the top of the furnace reaches the inner walls with impact, causing wear by abrasion and break conventional refractory materials. The invention, object of this report proposes a solution so as to thermally insulate the furnace, ensuring temperature in the housing of the order of 100 C. and reducing in the maximum the tar passage to the outer wall. The proposed solution is a combination of materials that alone could not meet the process needs, but together meet with accuracy and efficiency. For the region of the holes (considered in this report, the region comprised in a radius of between 100 mm and 200 mm taken from the hole center), the materials for promoting the isolation of internal surface of the metallic cylinder to the inside furnace are ceramic fiber blanket (13) with 2-inch thick, insulating material of low density and relatively low cost (this material is the main responsible for the reduction of the temperature in the furnace housing); smooth stainless steel plate of 1.5 mm thickness (14) covering the entire exposed surface of the blanket; refractory low cement concrete with at least 45% of Al2O3 mixed with metal fibers in stainless steel at a proportion of 2% by mass of concrete (15) usedthis concrete associated with the use of metallic fibers ensures integrity co concrete, avoiding the spread cracks due to process temperature variation. For the outside region of the holes and ignition points, the refractory concrete with metallic fibers is substituted by a refractory concrete with at least 47% of Al2O3 and maximum density of 2.27 kg/m3 applied on a hexagonal mesh, suitable for concrete anchorage refractories, with total thickness of 27 mm. The use of this concrete in this region coupled to a special curing process reduces the total percentage of full bore pores to 5%.

[0070] In FIG. 1, the area called the lower frustum (R3) consists of an inverted frustum, or in a transition of a circular cross-section to a square with rounded corners made of sheet metal. In FIG. 2, this cone (16) must be drilled to allow the passage of gases from biomass bed to the bottom, however, retaining the biomass. It is recommended that the holes have a diameter of 40 mm with an average spacing of 120 mm holes, or at least 20% of free passage area in the lateral area of the cone. The tilt angle for the cone should be such that promote the flow of charcoal without retentions flow. FIG. 1 shows for charcoal this angle (A2) varies between 30 and 50, with an optimum configuration the inclination of 36. The larger diameter of the frustum must follow the diameter of the central cylinder region.

[0071] Located in the lower portion of the lower frustoconical region and seen in FIG. 2, it is located a discharge valve (17) of charcoal. This valve consists of a blocking surface of the solid material located above it and must allow the passage of gas and condensables generated in the process. The valve must be mobile, clearing the passage at the end of the carbonization process in order to unload the charcoal produced. For that meets the minimum requirements, this valve must be flat with holes distributed over the surface uniformly so as to allow the passage of gases and retaining solid objects such as the inverted frustum. The diameter of the holes may be similar to that used in the cone, but the percentage of hollow area on the opening area must be at least 20% in order to ensure maximum flow for the gas flow. A flat surface with a hole (18) is installed on a frame provided with wheels (19), which in turn is on a track that allows the displacement of the cap and structure in only one direction. Turning the structure to the external environment there is a stainless steel metal rod (20). The set cover, frame with wheels and rod gives the name of car cover. In the lower region, some of the frustum holes (21) establish, through ducts, contact with the external environment for the injection of gases, such as atmospheric air, dosed for specific control mechanisms such as valves. These valves are ball valves, with ball in stainless steel and seat in material for temperature up to 150 C. The cover may be made of special steel alloy such as ASTM 572.

[0072] In FIG. 1, the total height of the volume (HC) comprised by the three regions (top (R1), core (R2) and lower frustum (R3)) on the diameter (D) of the central area (central cylinder) should vary between 1.0 and 2.2. The range of the central cylinder diameters ranges from 3300 mm and 4580 mm, recommended value as optimal configuration of the furnace.

[0073] The internal volume of the furnace, available to receive the biomass as feedstock, consisting of the three regions (top (R1) central cylinder (R2) and lower frustum (R3)), hereinafter called conversion zone may have volumetric capacity between 35 and 65 m3 with satisfactory results, and the optimum condition equal to 50 m3.

[0074] The conversion zone is maintained upright by a holding device whose shape is the association of a frustum and a cylinder with defined proportions made of sheet metal. This device consist of a fundamental point for the invention as will be shown below. This support structure shown in FIG. 2, also called furnace skirt (22) acts as an expansion box in the process, allowing the accumulated gases in the furnace base to recirculate, providing an atmosphere of hot gases and facilitating the conduction of process for the preheating of the biomass at the bottom of the furnace. In case of overpressure in the lower frustum region, the furnace skirt (22) is provided with specific pressure relief devices, called relief valves (23). Such relief valves must always be symmetrically distributed, and along the circumference of the furnace. The relief cap should be compatible with the area and weight of the furnace, raw material and process for this invention that corresponds to an area ranging between 0.25 and 0.6 m2 and weighing between 90 and 160 kg. Its position is limited to the lateral area of the frustum truncated cone and should be equipped with a duct or chimney (24) that directs the flow from the pressure increase in process or in a secure location. The smaller diameter of the support structure is equal to the diameter of the central cylinder region, with the point of union between the furnace skirt (22) and the central cylinder (R2) of about 200 mm above the lower limit. The higher diameter (DB) may vary between 1.25 to 1.35 times the diameter of the central cylinder region. The structure is coated internally with ceramic fiber blanket (25) with a density of 128 kg/m3, protected by a stainless steel flat plate (26) with 2 mm thick. The skirt also acts as an equalizer of the center of gravity of the furnace to make its operation safer about the possibility of an imbalance and toppling.

[0075] The furnace support base of the supporting structure of the furnace is provided with water channel (27) for cooling of the carbonization system coupling sealing. Next to the furnace support base are present guides for coupling the furnace to the support base of the carbonization system.

[0076] The invention, object of this specification, is provided with special holes called ignition points of process (28). These points may be located in the three regions of the conversion zone, however the ideal position for the ignition process is lower region of the central cylinder shown in FIG. 1, the position (H0) between 5% and 15% of the total height of cylindrical region measured from the base of the central cylinder. The location of this point in the limit given above allows a better control of the process, since although the isotherm of 200 C. gradually advance the ignition point for the rest of the furnace, the ignition in this height of the furnace allows that by means of the hot gases of the ignition process occurs a preheating of the entire conversion zone, increasing the isotherm velocity of 200 C. The size for the hole destined for the ignition process can vary between 4 and 6 inches. Similarly to the holes for the entry of atmospheric air, the ignition holes must be equipped with air flow control devices. As basic requirements for operation the guarantee of sealing, the hole area should not have obstructions (such as, for example, butterfly type valves whose outflow obstruction element bisects the flow passage area) and should be resistant to temperatures up to 200 C. Therefore, it is recommended the use of ball valve, with stainless steel ball and seat material for temperatures up to 200 C. Due to the high temperatures near the ignition point, it is installed in this region a refractory block with at least 70% of A1.sub.2O.sub.3, resistant to temperature of 1600 C.

[0077] In addition to the furnace described above, this invention makes exclusive use of the carbonization system described below and shown in FIG. 3.

[0078] The carbonization system, integrant part of the industrial furnace for the production of charcoal, comprises a movable support base (29), condensable recovery equipment (30), safety device for pressure relief (31), exhauster (32) and conducting ducts of gases and vapors (33). The carbonization system is a fixed equipment in a carbonization plant and the furnace is a movable device that couples to this system.

[0079] The movable support base is constituted by a cylindrical ring (34) of diameter equal to the largest diameter of the supporting structure, built of metallic material. Attached to the ring are the guides (35) which has the function of assisting the furnace positioning on the movable support base. Also on the movable support base are installed pivot pins (36) that fit on the guides of the furnace support base (37). Through this mechanism, with the aid of a system of nuts and spindles, the furnace is kept pressed against the movable support base. The seal (38) between the furnace and the movable support base is promoted by the use of special rubber for temperatures up to 90 C. Internally connected to the support ring, an inverted truncated cone (39), made of steel plate, allows uniform capture of the entire gaseous stream and condensable. The larger diameter of the cone should accompany the minor diameter of the supporting ring. The opening angle (A3) should be between 40 and 60 and the smaller diameter (DC) should be sufficient so that the gas flow speed does not exceed 10 m/s.

[0080] The movable support base receives this name for being allocated on an industrial weighing system, with articulated loading cells (40) (typically used for road scales) to absorb any lateral shift caused by collision between the furnace and the guides (35) and between the furnace and the movable support base. Therefore, the base has freedom to move vertically, allowing the correct weighing of the material.

[0081] Connecting the movable base support to the exhauster, there are a number of pipelines and equipment that conduct the gases and condensable flux out of the furnace. These gases and condensable can be used in other processes, such as combustion to supply heat energy, among others. Due to the presence of the weighing system, the connection between the smaller diameter of the inverted cone movable support base and the first section of the gas pipe must be made using a flexible junction (41). This junction (41) must be resistant to temperatures up to 265 C., made of stainless material and free of spaces where condensable material can accumulate and impair the flexibility of the joint. The solution presented in this invention is the use of two concentric pipes, being the smaller diameter tube (42) physically connected to the inverted truncated cone (39) of the movable support base and the largest diameter tube (43) connected to the expansion box (44). To prevent false air being sucked through the gap between the pipes, a flexible junction (41) made of glass fiber fabric coated with a plastic film, involves the ducts. This flexible junction (41) having one end attached by clamps to the cone (39) in the upper position and the other end attached to the larger tube (43) at the bottom. This assembly allows perfect operation of the weighing system, since it disconnects the set that is supported on the loading cells from the rest of the equipment. Is avoided, thus, the possibility of creating a lever effect, when the weight of the fuel/carbon contained in the furnace would be influenced or suffer changes depending on the gas flow and pipe handling and remaining system, which would be connected the cone.

[0082] Attached to the larger duct, used to connect the expansion junction to the movable support base, there is an expansion box (44) for reducing the flow rate and deposition of particulate matter and condensable. The speed in this region will be reduced to 50% of the speed in the duct. The expansion box is provided with two flow outputs. The first is located on the base of the box and is provided with a filter (45) which allows only the flow of condensable to a storage tank (46). The second output located on the box lateral of the expansion box allows output of gases, vapor and mist still dispersed in the gas stream. In this second output, the duct (33) is dimensioned not to have flow velocity exceeding 16 m/s. This duct follows leading the gases to the exhauster.

[0083] At the end of the duct (33), the connection to the exhauster is made perpendicular to the length of the pipe. This is because an explosion door (47) is installed at the end of the duct to ensure operational safety and integrity of the equipment in case of overpressure in the gas lines and/or return of the flame resulting from the flaring of gas in the incinerator. The explosion door is composed of a flat surface, which is kept closed by using only the own weight of the cover. In case of increased internal pressure, the door opens, relieving the internal pressure and directing, through a chimney (48), the exhaust flow to a safe region. This region or gas receiving location should preferably be suitable for burning the gas with capacity for complete combustion thereof.

[0084] The exhauster (32), one of the major component of the process, consists of a centrifugal exhauster with nominal flow of 10.000 m.sup.3/h and static pressure of at least 250 mmca. The rotor must be made of stainless steel. The equipment must be equipped with speed controller to allow adaptation thereof to the use of different forms of biomass and production process.

[0085] The industrial furnace for the production of charcoal has a device for rapid unloading of coal still warm in order to release the furnace for the carbonization process as soon as possible. FIG. 3 shows this device.

[0086] The basis for unloading comprises a platform that has a truncated cone (49) with the largest diameter compatible with the largest diameter of the bearing structure (DB) and smaller diameter compatible with the discharge valve (17). Below the platform there is a movable cylindrical container (50) with capacity between 24 and 32 m.sup.3 of charcoal. The movable cylinder has 3 to 5 water spray nozzles (51) with a flow rate ranging between 5 and 20 L/min, which are positioned in its interior to cool the burning coal during and after unloading.

[0087] On the procedure for operating the furnaces.

[0088] The industrial furnace for production of charcoal is loaded with biomass by the upper opening in the in the central cylinder region. For the loading, due to high volumetric capacity of these furnaces, it is preferably recommended the use f conveyor belt with or without silos or storage cylinders/stock, to ensure the constant supply of biomass to the furnace. This procedure ensures a quick loading time, which preferably should be less than 5 minutes to the feeding of 50 m.sup.3 of splinter in the furnace whose internal temperature must be above 200 C.

[0089] Then the top cover or top region is placed on the central region of the cylinder and fastened thereto with the aid of the threaded pivot pins, guides and nuts. The carbonization furnace is then moved to the carbonization system, where it is then positioned and locked on the movable support base.

[0090] Once the furnace is locked, the exhauster is turned on and adjusted so that its speed be compatible with the material used. Typically, it is aimed the maintenance of a constant volumetric flow rate of 6.000 m.sup.3/h, being the rotation speed adjusted so that the aforementioned flow rate be obtained.

[0091] The ignition process is then initiated. First it is assured that the valves located at the top of the furnace are opened to create a continuous flow of gases within the furnace. Only then the ignition itself takes place. Through the 4 ignition points of the process, a small amount not exceeding 2 kg of needles or burning coal, is injected into the furnace. The heat generated in these 4 points propagates by the lower region while a hot gas stream rises through the bed heating it. The strategic position of the ignition point allows the preheating to a temperature higher than 200 C. all the volume of the bed, optimizing the process, since with all the furnace above 200 C. the conduction of the carbonization becomes faster.

[0092] The carbonization process is then controlled by the air inlet holes, which are opened to permit entry of oxygen, which in turn leads to partial combustion of gases inside the furnace. This burning supplies energy to the rest of the endothermic phase of the carbonization process, being in the sequence closed the holes whose regions have reached the limit temperatures for the process.

[0093] This process of opening and closing of the valves is repeated until all of the internal volume is at temperatures above 350 C. Throughout all the period the furnace has its weight and temperature continuously monitored. The end of the process is reached when the weight of the furnace charge is equal to the weight stipulated as production target for the furnace.

[0094] When production target is reached, the furnace is then uncoupled and removed from the support base and the exhauster is turned off. The furnace is then positioned on the unloading basis wherein automatic unloading mechanisms connected to cover car rods unblock the orifice of the bottom cone region for the unloading of burning coal, with temperatures above 300 C. During the drop of the burning coal, water spray nozzles directed to the descending coal flow promote a superficial cooling of coal. The discharged coal is accumulated in a special container, metallic, non-insulated, for the cooling. Once completed the unloading process, which preferably does not exceed 3 minutes, the vessel containing hot charcoal is closed and sealed, from which follows to complete its cooling process.

[0095] The cooling process takes place by natural convection and the enthalpic effect of the removal of evaporation heat of the water that is sprayed, strategically in the regions of the carbon bed where the temperature exceeds 120 C.

[0096] This process step, which lasts 10 to 15 hours, ensures the release of the container furnace for continuous charging process, carbonization, unloading, loading, carbonization, unloading . . . and so on in cycles lasting between 3 and 6 hours.

[0097] The container furnace tested in pilot scale laboratory had its design optimized, resulting in the manufacture of a pilot furnace on an industrial scale. The changed items were especially related to increased wood put into the furnace capacity, improved instrumentation, control, mechanization, operating procedure, process and thermal size. In this furnace the parameters monitored during the running are: load weight, flow rate, composition, density, pressure and gas temperature, air inlet flow in load, temperature of sampled firewood in more than 70 points around the furnace volume and volume of pyrolignous generated.

[0098] All data was generated continuously in real time and simultaneously. The tests have converged to a stabilized process under the following conditions: volumetric yield of 1.3 st of wood for per m.sup.3 of charcoal, gravimetric yield of 35%, carbonization time of 3 h, generation of 6.500 m.sup.3/h per furnace with an average PCI of 1.700 kJ/m.sup.3, possibility of thermal power generation from furnace of 3 MW or equivalent to generating 1 MWe per 1000 tons of coal, producing 150 liters of pyroligneous per cycle, charcoal production with 200 kg/m.sup.3 bulk density. These results demonstrate that the industrial Container furnace of charcoal production, or Furnace Container Rima (FCR) consists of a pioneer industrial technology in charcoal cogeneration and thermal power capable of generating electricity technically and economically viable way.

[0099] The development of this project enabled the mass and energy balance detailing in the FCR, whose values show that in this furnace there is excess of oxygen; the combustion occurs with all products derived from the process (gas, tar, pyroligneous and coal). And in addition to the combustion reaction, it was verified that occur important intermediate reactions, such as carbon exothermic reaction with water vapor, gasification and cracking. These intermediate reactions which occur in the furnace, with an operational exclusivity that is being requested in this application, are responsible for an innovative result in the state of the art of carbonization technology. That is, only in the structural, operational, thermal and mechanical conditions of this project, it is possible to produce coal with a gravimetric yield of 35% while a gravimetric yield of 60% gas is obtained, against traditional values, around 30% for the generation of gas. This means that the furnace has a very significant difference from current carbonization furnaces: the generation or preferential production of gas relative to tar and pyroligneous (the condensable fraction ends up gasifying). This is an essential factor to promote the association of this carbonization project to a Thermoelectric central with simultaneous burning of biomass and gas carbonization. With a fraction of condensable contained in the generated gas transport, displacement, storage and piping become feasible to be conducted to a plenum or a balloon, where it is homogenized, and then to direct combustion in a boiler in order to promote the generation of electricity. [0100] i. The mass and energy balance, resulted in the verification of a highly efficient process. The thermal losses are inferior to 5%. The energy percentage available necessary to maintain or sustain the pyrolysis is 10%. The energy contained in the coal around 60% of the energy present in the wood and in the gases of 25%.

APPLICATION EXAMPLES

[0101] Below, it will be shown a series of possible configurations for the invention, which aim illustrate its several uses. And, although it can be exemplified by, it is not limited to the examples that follow.

Example 1

[0102] The industrial furnace of production of charcoal with capacity for 35 m3 can be loaded by the upper hole with wood cavacos, average granulometry between 100 and 120 mm. The furnace, already with the cover placed and locked, is placed on the carbonization system and locked on the movable support base. The exhauster is then switched on and the ignition on specific points, with ember, starts. The carbonization control by the opening and closing of the holes follows in order to provide energy for the endothermic phase. The process ends in about 3 hours, producing 2400 kg of charcoal with gravimetric yield of 33%.

Example 2

[0103] The industrial furnace for charcoal production with a capacity of 35 m3 can be loaded by the upper hole with wood small logs, average size of 200 mm. The furnace already with the cover placed and locked, is placed on the carbonization system and locked on the movable support base. The exhauster is then switched on and the ignition on specific points, with ember, starts. The carbonization control by the opening and closing of the orifices follows in order to provide energy for the endothermic phase. The process ends in about 5 hours, producing 2800 kg of charcoal with gravimetric yield of 35%.

[0104] While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.