INDUSTRIAL COMPLEX FOR THE PRODUCTION OF CHARCOAL

Abstract

An industrial complex for producing charcoal from briquetted wood waste includes a section for heat carrier preparation, a section for ground wood waste preparation, a wood drying section equipped with a driving device, a briquetting section and a low-temperature pyrolysis section. The section for preparing the gaseous heat carrier is in the form of a heat generator and is equipped with a furnace chamber for receiving combustion gases, a unit for incinerating recovered pyrolysis gases and a unit for introducing the steam-gas mixture returned from the drying section. The section for ground wood waste preparation includes a receiving hopper for the feedstock, crushing and milling equipment and a storage hopper equipped with a batch feeder. The wood drying section is equipped with a drying device that operates in a mode of combined circulation in a suspended state of the steam-gas heat carrier and crushed wood. A section for separating the mixed stream exiting the drying device includes a cyclone and a receiving hopper. The pipeline upstream of the cyclone is equipped with a device for regulating the target moisture of wood particles. The separation section includes a flue for dispersing waste gases from drying. The briquetting section is equipped with an extrusion-type press. The section for low-temperature pyrolysis is equipped with devices for producing charcoal.

Claims

1. An industrial complex for the production of charcoal from briquetted wood waste, comprising a heating agent preparation section, a crushed wood waste preparation section, a wood drying section equipped with a drying device, a briquetting section, and a low-temperature pyrolysis section, characterized in that said gaseous heating agent preparation section is embodied in the form of a multipurpose heat generator equipped with a combustion chamber for producing flue gases, a waste pyrolysis gas combustion unit, and a unit for supplementing the generated heating agent with, at least, a portion of the low-oxygen and high-steam content gas-steam mixture returned from the drying section; furthermore, the crushed wood waste preparation section located upstream of the drying section includes at least one feedstock feed hopper, crushing and grinding equipment, and at least one storage hopper located upstream of the inlet channel of the drying device and equipped with a metering feeder; furthermore, the wood drying section is equipped with a drying device operating under the condition of a joined circulation of the suspended gas-steam heating agent and crushed wood within the working zone embodied in the form of a looped channel, while the drying device includes a wood particle input unit, a low-oxygen heating agent input unit, a wood particle removal unit configured to enable a complete removal of the wood particles with the gas-steam flow, or a complete or partial return thereof for an additional drying cycle, wherein said removal unit is configured to prevent oxygen from penetrating into the working zone of the drying device; furthermore, the section for separating a mixed flow exiting the drying device into a gas-steam mixture and crushed wood is configured to recover at least a portion of the gas-steam mixture in the multipurpose heat generator of the gaseous heating agent preparation section and includes at least one cyclone and one feed hopper, placed downstream relative to the drying device, wherein the pipeline upstream of the cyclone is equipped with a means for controlling target moisture content of the wood particles by condensing moisture from the gas-steam flow; furthermore, the separation section also includes a stack for dispersing at least a portion of the flue gases resulting from drying with said stack being provided with control valves and/or dampers, the positioning of which ensures a level of pressure inside the complex that suppresses oxygen from leaking into the system, while allowing at least a portion of flue gases to exit the system; furthermore, the briquetting section is equipped with at least one press, preferably, of extrusion type; furthermore, the thermostabilized low-temperature pyrolysis section is equipped with at least two charcoal production devices, each of which includes a thermally insulated housing provided with a system of gas ducts, wherein the working zone of each device is embodied in the form of a looped channel provided with a gas-permeable recuperator installed inside said looped channel, a heat-resistant fan, and a butterfly damper, while the gas duct system is configured to transport pyrolysis gases to the multipurpose heat generator installed at the gaseous heating agent preparation section; the pyrolysis section is additionally equipped with removable devices for loading and unloading briquettes.

2. The industrial complex for the production of charcoal from briquetted wood waste according to claim 1, characterized in that the means for controlling the target moisture content of the wood particles by condensing moisture from the gas-steam flow is embodied in the form of a movable sleeve mounted coaxially on the pipeline and configured to move therealong.

3. The industrial complex for the production of charcoal from briquetted wood waste according to claim 1, characterized in that the means for controlling the target moisture content of the wood particles by condensing moisture from the gas-steam flow is embodied in the form of a folding half-sleeve mounted coaxially on the pipeline and configured to move both in the longitudinal and transverse directions relative to the pipeline axis.

4. The industrial complex for the production of charcoal from briquetted wood waste according to claim 1, characterized in that the wood drying section is equipped with a system responsible for tuning and controlling the drying process, including the adjustment of temperature, oxygen content, humidity and volume of heating agent supplied to the drying device; adjustment of the volume and feed rate of crushed wood waste supplied to the drying device; adjustment of the gas-steam heating agent and crushed wood joint circulation rate; adjustment of the pressure level inside the drying device and adjustment of the residence time of the circulating flow of suspended wood particles inside the looped channel.

5. The industrial complex for the production of charcoal from briquetted wood waste according to claim 1, characterized in that the briquetting section is equipped with a system responsible for tuning and controlling the briquetting process, including the adjustment of humidity and temperature of the wood particles supplied for extrusion; and adjustment of extrusion temperature and rate.

6. The industrial complex for the production of charcoal from briquetted wood waste according to claim 1, characterized in that the low-temperature pyrolysis section is equipped with a system responsible for tuning and controlling the process of thermostabilized pyrolysis, including the adjustment of pyrolysis gas temperature and circulation rate; and adjustment of the volume of pyrolysis gases supplied for combustion at the gaseous heating agent preparation section.

7. The industrial complex for the production of charcoal from briquetted wood waste according to claim 1, characterized in that the gaseous heating agent preparation section is equipped with a system responsible for tuning and controlling the heating agent preparation process, including the adjustment of flue gas volume; adjustment of the volume of the return gas-steam flow after drying; and adjustment of the operation of burners for combustion of pyrolysis gases.

8. The industrial complex for the production of charcoal from briquetted wood waste according to claim 1, characterized in that the site for the preparation of crushed wood waste is equipped with a system responsible for tuning and controlling the technological process for wood feedstock preparation, including the adjustment and control of the size of wood particles supplied for drying.

9. The industrial complex for the production of charcoal from briquetted wood waste according to claim 1, characterized in that said complex is provided with thermal insulation.

10. The industrial complex for the production of charcoal from briquetted wood waste according to claim 9, characterized in that the portion of the pipeline upstream of the cyclone at the mixed flow separation section allows for the adjustment of the amount of thermal insulation.

Description

[0037] The complex depicted in FIG. 1 represents only one of the most preferred configuration options of the proposed solution. However, there could be other design solutions of the Complex, which would enable achieving the claimed technical result. A mandatory requirement for the implementation of the invention is the use of the author-designed thermal units (looped drying device; low-temperature pyrolysis furnace equipped with a powerful gas-permeable recuperator), as well as a closed-loop process gas recycling system as part of the Complex.

[0038] According to FIG. 1, the Complex comprises a crushed wood waste preparation section (1) provided with storage, crushing and grinding, and dosing equipment; a gaseous heating agent preparation section (2) equipped with a multipurpose heat generator; a wood drying section (3) equipped with a loop-type drying device; a device for controlling the target moisture content of the wood particles (4), the structural implementation of which may vary (several embodiments are described in the dependent claims 2 and 3 of the invention); a mixed flow separation section (5) equipped with at least one cyclone; a storage hopper (6); an extrusion briquetting section (7); a low-temperature pyrolysis section (8) equipped with at least two low-temperature pyrolysis furnaces; a packaging section (9), which utilizes the original packaging easily distinguishable for a consumer; and a finished product warehouse (10).

[0039] The industrial complex depicted in FIG. 1 (schematic diagram) operates as follows.

[0040] The initial feedstock (forest clearing and/or wood-processing waste, such as sawdust, shavings, bark, wood chips, wood powder, timber offcuts, as well as from off-grade wood, such as branches, pulpwood, and second-growth timber) is supplied to the crushed wood waste preparation section (1), where wood particles (11) are obtained. Depending on the quality of the waste supplied for processing, a certain type of the crushing and grinding equipment is used, while the only requirement for the wood particles (11) has to do with controlling the maximum permissible size thereof (not to exceed 5 mm). In this case, there is no need to control the fractional composition with respect to the particle sizes less than 5 mm, since the utilized drying device eliminates the initial fluctuations under the conditions of a dynamic weighted looped heat flow. Section (1) contains at least one feed hopper provided with an initial feedstock supply line. The transport line equipped with a metering feeder transfers wood particles (11) from the feed hopper to the drying device of section (3) embodied in the form of a looped channel, preferably with a circular cross-section having the same size over the entire length of the channel.

[0041] The gaseous heating agent preparation section (2) is equipped with a multipurpose heat generator operating based on gaseous, as well as solid fuel. Once the Complex reaches the operating conditions, the heat generator generates process heat, which is supplied to the drying unit of section (3) practically without any losses due to recycling of process gases generated during briquette production. The dynamic process gas flows generated during briquette production (pyrolysis gases, gas-steam phase of the drying device) are looped into the multipurpose heat generator of section (2). At the heat generator outlet, a heating agent (12) is obtained, which is supplied to the drying device under the perfect conditions (in terms of temperature, low oxygen content, and high steam content). Moreover, by recycling a gas-steam phase (15), in addition to energy savings it becomes possible to reduce the oxygen content and increase the steam content of the heating agent supplied for drying. Pyrolysis gas (18), generated at the low-temperature pyrolysis section (8), is supplied for combustion inside the multipurpose heat generator, which makes it possible to almost completely satisfy all the heat-related process needs of the production. Thus, recycling of flue/process gases in the multipurpose heat generator provides an efficient preparation of wood particles in section (3), and minimizes the overall energy consumption of the production.

[0042] Wood particles (11) and heating agent (12) are supplied to the author-designed drying device of section (3). The looped drying device operates under the repeating cycle conditions within the working channel enabled by the presence of high-capacity fans and a recycling unit, which returns feedstock for repeated heat treatment, both installed within the working channel. The recycling unit is configured to control the volume of recirculating flow inside the channel.

[0043] Mixed flow (13), consisting of dried wood particles and gas-steam phase, is supplied as a suspension from the drying device to the transport line equipped with a means (4) for controlling the ultimate moisture content of the wood particles. The design solution of such means may vary, e.g., it can be embodied in accordance with claim 2 or 3 of the invention. The only requirement for this means is of a technological nature, namely: the specified means should allow for the implementation (to a certain degree, depending on the specific requirements) of condensation of a portion of steam from the gas-steam phase to achieve the specified target moisture content of the wood particles (16). This means (4) must be dynamic and capable of simply and quickly changing the amount of thermal insulation of the transport line section where it is installed.

[0044] After adjusting the moisture content of the wood particles using means (4), mixed flow (13) is supplied to section (5) for separation. Section (5) is equipped with at least one cyclone configured to separate the gas-steam phase into two flows. One flow (14) is directed through the stack to the atmosphere, and another (15) is returned to the gaseous heating agent preparation section.

[0045] According to the diagram shown in FIG. 1, the solid phase in the form of wood particles (16) is supplied from the cyclone of section (5) to the storage hopper (6), and then to the briquetting section (7). In practice, depending on the specific production situation, several options for delivering wood particles (16) to the extruders of section (7) can be implemented, namely:from the cyclone of section (5) to the storage hopper (6) (as shown in FIG. 1);from the cyclone of section (5) directly to the extruders of section (7) (not shown in FIG. 1);from the cyclone, one portion of wood particles (16) is supplied to the storage hopper (6), and anotherdirectly to the extruders of section (7) (not shown in FIG. 1).

[0046] The briquetting section (7) is equipped with at least one press, preferably, of an extrusion type. The number of presses in the Complex is determined by the design capacity of the plant. It is more practical to direct briquettes (17) directly to the low-temperature pyrolysis section (8).

[0047] At this section (8), briquettes (17) are used to fill the replaceable removable devices carrying briquettes (17) to the author-designed thermostabilized low-temperature pyrolysis furnaces. In the proposed industrial complex, the furnace for producing charcoal operates on a continuous basis with periodic loading and unloading of the replaceable removable devices. The residence time of one batch of briquettes in the furnace does not exceed six hours, and is typically 4-5 hours. The optimal duration of briquette treatment in the furnace is determined by visual inspection of the flue gases (based on the flue gas color). The resulting pyrolysis gas (18) is supplied to the multipurpose heat generator of section (2).

[0048] After unloading from the pyrolysis furnace, charred briquettes (19) require no forced cooling. This is due to their stable geometric shape (hollow cylinder). After the briquettes are naturally cooled to ambient temperature, they are supplied to the packaging section (9), where they are packed in the original packaging and dispatched to the warehouse and/or consumer.

[0049] All process heating devices within the Complex, as well as transport lines used to transfer the heating agent are thermally insulated.

[0050] The above-described operation of the proposed Complex is related to the process dynamics of solid and gaseous products from the moment of wood feedstock delivery to the moment of producing the target charred briquette (19).

[0051] From the environmental standpoint, it is important to mention that the proposed production complex operates based on a waste-free technology. Moreover, waste-free production is realized with respect to both the solid part of the feedstock and process gases from the drying section and low-temperature pyrolysis section, formed during the production process.

[0052] At this time, the proposed complex for the production of briquetted charcoal has passed pilot plant tests using various initial feedstock. The tests were successful and proved the adaptability of the Complex to any wood waste without changing the process line as a whole.

[0053] The tests also showed that the Complex in question is much more effective from the energy standpoint compared to the prior art.

[0054] Considering the simplicity and reliability in manufacturing and operation, the proposed Complex can be recommended for widespread implementation into the charcoal production.