Method and apparatus for torrefaction

Abstract

The torrefaction method includes: passing biomass into a treatment chamber; heating the biomass in the treatment chamber to a predetermined temperature to pyrolyze the biomass and release syngas from the biomass, wherein the syngas contains at least 20% of the power contained in the biomass flow; and oxidizing the syngas to heat the biomass in the treatment chamber.

Description

[Technical field]

[0001] The present invention relates generally to a method and apparatus for torrefaction. [Background technology]

[0002] In countries that lack resources of fossil fuels such as coal or oil, or that want to transition to sustainable energy production, biomass is considered as an alternative energy source. In this respect, gas obtained by decomposition of organic matter in the absence of oxygen, usually called biogas, has been used for quite some time. However, biogas generally requires gas tanks for storage, which greatly limits the storage capacity. Furthermore, some components are considered to be toxic or greenhouse gases. Biogas production also produces fermentation residues that remain after its production. The fermentation residues can be difficult to dispose of.

[0003] Torrefaction has been found to convert biomass into biocoal or biochar, a solid with a lower moisture content and an increased amount of carbon, especially by mass percentage, compared to the input biomass. Biomass usually means wood chips, but a wide variety of biomasses are possible. The biocoal obtained by torrefaction has been found to have a lower weight, especially a lower oxygen weight, and a higher energy density in terms of volume and mass, compared to the input biomass. The biocoal derived from torrefaction can be used in the same way as conventional coal for energy generation in coal-fired power plants. If the biocoal rating is high enough, other applications, such as steel production, are also possible. Furthermore, biocoal is chemically stable and therefore can be stored and transported as easily as conventional coal.

[0004] In principle, torrefaction is a pyrolysis process essentially at atmospheric pressure, in the absence of oxygen other than that contained in the biomass itself. Usually, the biomass is subjected to 200°C to 350°C, with a residence time of 10 to 120 minutes. The quality of the biocoal obtained depends on said temperature and residence time. During torrefaction, synthesis gas is separated from the biomass. It contains tars, H2, CH4 and / or CO. It is usually gaseous, but may also contain droplets of condensed tars. It is mainly cooled to condense and remove the tars, so that its use in conventional applications is possible, for example in gas engines for generating electrical energy.

[0005] Conventional torrefaction processes typically provide biocoal with an energy density of 20-21 GJ / ton. As discussed in detail below, the energy density depends primarily on the temperature and residence time of the biomass in the treatment atmosphere, with longer residence times or higher temperatures providing biocoal with a lower amount of energy from the original biomass but a higher energy density.

[0006] However, as the energy density increases, the amount of tars contained in the synthesis gas produced also increases. This requires an increased amount of tar to be removed from the synthesis gas. Otherwise, the tars in the synthesis gas would naturally condense and could foul or clog the gas engine. Also, when tar is used, it can release polycyclic aromatic hydrocarbons, which have been found to be associated with various forms of cancer. Therefore, tar is usually replaced by bitumen, which makes it more difficult to utilize the tars produced during torrefaction.

[0007] WO 2015 / 084162 A1 describes a modified dryer that operates on a different principle to that used in conventional torrefaction plants. The invention uses heat conduction to torrefy biomass in a vibrating reactor, where a heated solid non-perforated plate is sealed inside the reactor to separate the upper biomass from the gas used to heat the lower plate. Also, the synthesis gas generated in this way is used to power a gas engine, the exhaust output of which is recirculated to heat the reactor plate. When the gas engine is connected to a generator, the unused energy is recovered for use in other parts of the plant or sent elsewhere. Summary of the Invention

[0008] The invention is defined in the independent claims, whilst further aspects of the invention are described in the dependent claims, the drawings and the following text. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 shows a torrefaction apparatus according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing the reaction and product profiles of the torrefaction process for different energy capacities. Modes for carrying out the invention

[0010] 1 shows a torrefaction apparatus having a treatment chamber 11a and an oxidizer 12. Before describing the torrefaction apparatus in detail, some general aspects of the present invention will be considered.

[0011] According to one aspect, a torrefaction apparatus comprises: - Processing chamber arranged for torrefaction of biomass; - an oxidizer arranged to heat the treatment chamber; and - Conduit for the synthesis gas released from the biomass during torrefaction Including, The conduit is positioned to conduct the syngas from the treatment chamber to the oxidizer; the oxidizer is configured to oxidize the syngas and release a power of at least 20% of the power contained in a maximum flow of biomass passing through the treatment chamber.

[0012] The resulting biocoal is hydrophobic and can be easily stored without additional weather protection. The resulting biocoal can be made water resistant with certain additives. Biocoal can be subject to dust ignition in existing installations.

[0013] In the following, the flow of biomass refers to the amount of biomass per unit of time. For example, the flow of biomass is the mass of biomass in kilograms [kg] per unit of time [hr], i.e.

[0014]

number

[0015] It can be expressed as:

[0016] The maximum flow of biomass through the treatment chamber represents the amount of biomass that the treatment chamber can process in a unit time. Since the flow of biomass is a quantity per time, the energy contained in that quantity per unit time corresponds to power.

[0017] In some embodiments, the conduit is configured to maintain the syngas temperature during operation above the condensation temperature of the syngas from the treatment chamber. In various embodiments, the syngas temperature is maintained above 330° C. and / or at least 50° C. above the maximum temperature of the biomass in the treatment chamber. In various embodiments, the maximum temperature of the biomass is the core temperature of the individual particles. Typically, the core temperature lags the ambient temperature and may differ from the surface temperature of the particles. Combusting the syngas in an oxidizer adjacent to the treatment chamber also limits the effort required to maintain the syngas temperature above its condensation temperature.

[0018] For example, while passing through the treatment chamber, the biomass is heated to a maximum of 280° C., and the conduit therefore maintains the syngas temperature at 330° C. In another example, the biomass is heated to a maximum of 300° C., and the conduit therefore maintains the syngas temperature at 350° C. The biomass reaches its maximum temperature just before it leaves the treatment chamber.

[0019] In some embodiments, the conduit is insulated.

[0020] In some embodiments, the conduit and / or treatment chamber includes an air intake that allows for controlled combustion of a portion of the syngas. This typically means that a portion of the syngas is combusted before it reaches the oxidizer. For example, in an apparatus having an oxidizer that burns about 4 MW, the syngas combusted in the conduit and / or treatment chamber corresponds to about 100 kW.

[0021] In some embodiments, the oxidizer is configured to provide oxidation that releases at least 23%, 25%, or 27% of the power contained in the maximum flow of biomass passing through the treatment chamber. In some embodiments, the oxidizer is configured to provide oxidation that releases no more than 36% or no more than 40% of the power contained in the maximum flow of biomass passing through the treatment chamber. In some embodiments, the oxidizer is configured to provide oxidation that releases 23%-40% of the power. In some embodiments, the oxidizer is configured to provide oxidation that releases 23%-36% of the power. In some embodiments, the oxidizer is configured to provide oxidation that releases 25%-40% of the power. In some embodiments, the oxidizer is configured to provide oxidation that releases 25%-36% of the power. In some embodiments, the oxidizer is configured to provide oxidation that releases 27%-40% of the power. In some embodiments, the oxidizer is configured to provide oxidation that releases 27%-36% of the power.

[0022] The more power the oxidizer can handle, the higher the energy density of the resulting biocoal. Higher energy density makes the biocoal applicable for additional uses, such as steel production.

[0023] In some embodiments, the oxidizer is configured to combust the syngas at a temperature greater than 750° C., more preferably greater than 850° C. or 1050° C. In various embodiments, the oxidizer is configured for the syngas to pass therethrough with a residence time of 1 second, preferably 2 seconds or less. For an oxidizer configured with a residence time of 1 second, a temperature of at least 850° C. has been found to allow essentially complete combustion of the combustible components of the syngas. In various embodiments, the oxidizer temperature and the residence time of the syngas are adjusted to allow essentially complete combustion.

[0024] In some embodiments, the oxidizer is configured to maintain the treatment chamber at 400° C. to 650° C., preferably about 500° C. In further embodiments, the torrefaction apparatus includes a cooling structure that dissipates a portion of the thermal energy from the oxidation in a sink to control the temperature of the treatment chamber. In various embodiments, the cooling structure allows for plant construction of low-cost materials.

[0025] In some embodiments, the oxidizer is configured with an oxidizer air feed. The oxidizer air feed is configured to maintain the temperature of the treatment chamber below 600° C., preferably below 550° C., by generating a flow of dilution air from the surroundings toward the treatment chamber. In some embodiments, additionally or alternatively, warm gas is sent from the treatment chamber to a dryer where the biomass is dried before entering the treatment chamber. The oxidizer air feed in some embodiments is a blower or fan.

[0026] In some embodiments, the temperature rating of the process chamber is less than 600° C., preferably less than or equal to 550° C. The temperature rating refers to the temperature at which the process chamber can be operated without damaging the equipment. Process chambers with higher temperature ratings require different materials and different construction, which usually makes the process chamber much more expensive.

[0027] In some embodiments, the processing chamber reaches temperatures above 500° C., as high as 950° C., and uses high grade materials and insulation to protect lower grade materials and help increase biomass throughput in the production of very high grade carbon materials such as coke.

[0028] In some embodiments, the treatment chamber includes feeding, conveying and / or distribution elements configured to hold a certain amount of biomass in the treatment chamber for a time period between 15 and 30 minutes. In some examples, the above configuration leads to biocoal production with an energy content between 22 GJ / ton and 30 GJ / ton for a biomass input of 3100 kg / hour, corresponding to a power of about 14.6 MW, since the temperature and residence time substantially determine the energy content of the product.

[0029] In some aspects, the treatment chamber is configured to minimize natural air exchange between the contents and the surrounding air, the treatment chamber preferably has an inlet with an airlock and an outlet with an airlock, the biomass is transported through the inlet, the treatment chamber and the outlet, and the treatment chamber is preferably maintained at a pressure lower than the ambient air pressure. By keeping the treatment chamber at lower than ambient air pressure, a small leak in the treatment chamber will not release syngas to the surroundings and will not pose any health or safety hazards due to syngas being released to the surroundings. In some aspects, the conduit has a fan or blower to create a low pressure in the treatment chamber.

[0030] In some embodiments, the syngas contains tars, H2, CH4, and / or CO, and the oxidizer is preferably configured to combust at least a portion of the tars.

[0031] According to a further aspect, the torrefaction method comprises: - Sending the biomass to the processing room; - heating the biomass in the treatment chamber to a predetermined temperature to pyrolyze the biomass and release a synthesis gas from the biomass, the synthesis gas containing at least 20% of the power contained in the flow of biomass; and - Oxidizing the synthesis gas to heat the biomass in the treatment chamber Includes.

[0032] In some embodiments, the amount of biomass is held in the treatment chamber for 15-30 minutes.

[0033] In some embodiments, the syngas is maintained at a temperature above the condensation temperature of the components of the syngas. In various embodiments, the syngas temperature is maintained above 330° C. and / or at least 50° C. above the maximum temperature of the biomass in the treatment chamber. Maintaining the syngas at these temperatures prevents the tars from condensing before they reach the oxidizer where they are combusted.

[0034] In some embodiments, the syngas is mixed with a controlled flow of air, which is preferably heated. Mixing the syngas with some air allows for combustion control to maintain the temperature of the syngas.

[0035] In some embodiments, the oxidizer combusts the syngas at temperatures greater than 750° C., more preferably greater than 850° C. or 1050° C., to provide thermal energy for heating the biomass in the treatment chamber. In some embodiments, the syngas passes through the oxidizer within at least 1 second, preferably within 2 seconds. Combustion at these temperatures allows for significant oxidation of the tars.

[0036] In some embodiments, the air flow regulates the heat energy provided to the treatment chamber. In some embodiments, the heat energy is further sent to a dryer where the biomass is dried before entering the treatment chamber. In some embodiments, the oxidizer air feed creates pressure to direct the warm gas, containing the heat energy from the oxidation, through the treatment chamber and into the dryer. This eliminates the need for an additional fan between the oxidizer and the dryer, which would otherwise have to be configured to accommodate the much higher temperatures.

[0037] It has been found that the amount of tar produced during torrefaction can be reduced by combustion in the treatment chamber, conduit and / or oxidizer. The burned tar may be used to heat the biomass in the treatment chamber and / or oxidizer.

[0038] Returning to the description of FIG. 1, in various embodiments, biomass 21 is stored and sent to a dryer 17, where it is heated to remove water, preferably by evaporation. The dried biomass 22 is then fed to a treatment chamber 11a. In operation, the oxidizer 12 provides thermal energy 25 to the treatment chamber 11a, which produces, on the one hand, synthesis gas 23, such as tar, hydrogen, methane and carbon monoxide, and, on the other hand, a solid component 24 by treating the dried biomass 22 in a torrefaction step. The solid component is hereinafter referred to as biochar or biocoal. In various embodiments, the oxidizer is configured to combust the synthesis gas 23 to provide the thermal energy 25.

[0039] The flow of syngas 23 in a given time period contains at least 20% of the energy of the flow of biomass in the same time period. The oxidizer 12 is therefore configured to burn a corresponding amount in that time period. As understood in the art, this means that the air or oxygen feed to the oxidizer is sized accordingly. At least a portion of the 20% of the energy content of the biomass treated in said time period is essentially used to heat the treatment chamber 11a for approximately that time period.

[0040] The torrefaction apparatus further includes a conduit 13 for supplying the synthesis gas 23 to the oxidizer 12. In various embodiments, the treatment chamber 11a and the conduit 13 are configured to maintain the temperature of the synthesis gas 23 higher than the condensation temperature of most of the components of the synthesis gas. In particular, components with high condensation temperatures, such as tar, are sent to the oxidizer 12 in a gaseous state. Thus, the amount of tar discharged from the torrefaction apparatus is reduced.

[0041] As will be explained further below, this allows the production of biocoal 24 with a higher energy density, in particular in terms of energy content per unit mass. In particular, the energy density of the biocoal produced according to the invention is at least 22 GJ / tonne, preferably 24 GJ / tonne, although grades of 28 GJ / tonne and above are also possible.

[0042] In various embodiments, the conduit 13 is disposed with insulation to maintain the temperature of the syngas 23. In further embodiments, the conduit 13 is disposed with a first air feed 15 configured to provide heated compressed air to the conduit 13. In various embodiments, the treatment chamber 11a is disposed with a second air feed 16 configured to provide heated compressed air to the treatment chamber 11a. In various embodiments, the air in the first and second air feeds 15, 16 is heated by the oxidizer 12.

[0043] The heated air supplied to the treatment chamber 11a and / or the conduit 13 heats the syngas 23 and allows for the controlled combustion of a portion of the tar to maintain the temperature of the syngas 23. The combustion of a portion of the tar reduces the amount of tar in the syngas 23.

[0044] In various embodiments, the first and second air feeds 15, 16 provide air at ambient temperature. In further embodiments, the first and second air feeds 15, 16 provide air heated by the oxidizer 12. In further embodiments, the first and second air feeds 15, 16 are connected to the same compressed air source. In various embodiments, the first and second air feeds are controlled in a closed loop to maintain the temperature of the syngas 23 above the condensation temperature of most of the components of the syngas 23.

[0045] In various embodiments, the oxidizer 12 is housed in a heating chamber 11b disposed adjacent to the treatment chamber 11a. In various embodiments, the heating chamber 11b is disposed below the treatment chamber 11a. The heating chamber 11b is disposed to hold thermal energy 25 adjacent to the treatment chamber 11a. The oxidizer 12 is further disposed with an oxidizer air feed 14. In various embodiments, the oxidizer air feed 14 is disposed to provide oxygen for oxidizing the syngas 23. In various embodiments, the oxidizer air feed 14 is configured to provide more air than is required to oxidize the syngas 23. In various embodiments, the oxidizer air feed 14 is configured to provide air to regulate the thermal energy 25 provided to the treatment chamber 11a and thus control the temperature of the treatment chamber 11a. In various embodiments, the oxidizer air feed 14 provides ambient air. In different embodiments, the oxidizer 12 is provided with a supply line to provide oxygen from a source other than air.

[0046] In various embodiments, the oxidizer 12 is configured to combust the syngas 23 at a temperature greater than 750° C., preferably greater than 850° C., and more preferably greater than 950° C. or 1050° C. In various embodiments, the oxidizer is configured to allow the syngas to pass through within a residence time of at least 1 second, preferably 2 seconds or more. The residence time and oxidizer temperature are preferably configured to allow essentially complete combustion of combustible components of the syngas 23. In various embodiments, the oxidizer air feed 14 is configured to control the thermal energy 25 generated by the oxidizer 12 such that the treatment chamber 11a is heated to 400° C. or greater, preferably 500° C.

[0047] In various embodiments, the heating chamber 11b is maintained at 600° C. or less, preferably 550° C. By limiting the temperature of the treatment chamber 11a and / or heating chamber 11b, less expensive materials can be used to construct the treatment chamber 11a and / or heating chamber 11b, or the entire torrefaction apparatus, thus allowing for an economically viable design. In various embodiments, air from the oxidizer air feed 14 is used to regulate the thermal energy 25 between the oxidizer 12 and the treatment chamber 11a to regulate the temperature of the treatment chamber 11a and / or heating chamber 11b. In various embodiments, the oxidizer air feed 14 has two separate fans to supply air for oxidizing the syngas 23 and regulate the temperature of the treatment chamber 11a and / or heating chamber 11b.

[0048] In various embodiments, the air provided by the oxidizer air feed 14 and the oxidized syngas form a flow of warm gas 26 that is used as a heat source. In various embodiments, the flow of warm gas 26 passes from the heating chamber 11b to the dryer 17. In the dryer 17, the flow of warm gas 26 dries the biomass 21 by evaporating water 27. The flow of warm gas 26 and the evaporated water 27 are then discharged from the dryer 17.

[0049] In further embodiments, the dryer 17 is located adjacent to the treatment chamber 11a. In various embodiments, the oxidizer air feed 14 is configured to supply air to the oxidizer 12 under sufficient pressure such that the flow of warm gas 26 is directed from the heating chamber 11b to the dryer 17. In various embodiments, the flow of warm gas 26 is mixed with the biomass 21. In various embodiments, the oxidizer 12 and the dryer are arranged such that the flow of warm gas 26 heats the dryer 17 without contacting the biomass 21. In various embodiments, the piping for the warm gas 26 is located between the chamber with the oxidizer 12 and the dryer 17. Preferably, the dryer is a cross-flow dryer, where the flow of warm gas 26 passes perpendicular to the flow of biomass 21. In further embodiments, the flow of warm gas 26 and the flow of biomass 21 pass through the dryer 17 simultaneously in the same direction or counter-currently in opposite directions.

[0050] In various embodiments, an oxidizer sized to process a syngas containing at least 20% of the power of the biomass flow is configured with an oxidizer air feed 14 that provides a sufficient amount of oxygen to combust essentially all of a corresponding flow of combustible syngas containing at least 20% of the power of the biomass flow. In various embodiments, the oxidizer air feed 14 provides more oxygen than is consumed in combustion with the syngas.

[0051] In various embodiments, the process chamber 11a is maintained at a pressure different from the ambient pressure. In some embodiments, the pressure in the process chamber 11a is lower than the ambient pressure. This prevents the synthesis gas 23 generated in the process chamber 11a from escaping to the environment, which could otherwise pose a health risk to operators and could also ignite if the synthesis gas escapes from the process chamber 11a and comes into contact with the ambient air.

[0052] In various embodiments, the treatment chamber 11a has an inlet airlock 18 that allows dried biomass 22 to enter the treatment chamber 11a while preventing air exchange between the interior of the treatment chamber 11a and the surroundings. In various embodiments, the treatment chamber 11a has an outlet airlock 19 that allows biocoal 24 to exit the treatment chamber 11a while preventing air exchange between the interior of the treatment chamber 11a and the surroundings.

[0053] The conduit 13 has a fan 20 for moving the syngas 23 from the treatment chamber 11a to the oxidizer 12. In some embodiments, the pressure within the treatment chamber 11a drives the syngas 23 to the oxidizer 12 and a fan is not required. In further embodiments, the fan 20 generates a pressure inside the treatment chamber 11a that is lower than the ambient pressure. Thus, even if there is a hole in the treatment chamber 11a, little or no syngas will leak from the treatment chamber 11a to the ambient.

[0054] 2 is a schematic diagram showing the embodiment of reactants in the treatment chamber 11a and the embodiment of products with different energy contents. In an embodiment that essentially includes biomass from wood, the reactants sent to the treatment chamber 11a mainly include carbon C, oxygen O, and hydrogen H. In various embodiments, the wood-derived reactants further include ash, moisture contained in wood if wood is used, moisture from hydrogen, and moisture from air. In one embodiment, about 49% of the mass of wood is carbon C, about 44% is oxygen O, about 6% is hydrogen H, and the remainder (about 1%) is ash, nitrogen, and other elements. Other reactants are moisture from different sources, such as wood moisture, moisture from hydrogen, and moisture from the air that enters the treatment chamber 11a with the dried biomass and / or compressed air.

[0055] The three sloping solid lines in Figure 2 show the qualitative distribution of biomass content into biocoal and syngas at various energy densities per tonne of biocoal 24 after torrefaction. In particular, the left side of each sloping solid line is biocoal 24 and the right side of each sloping solid line is syngas 23.

[0056] Therefore, the slope of the biocoal line with an energy density of 21 GJ / tonne shows that the biocoal content is not significantly different from that of dry biomass. Most importantly, the carbon content of the resulting syngas is negligible. Therefore, very little tar needs to be removed from the syngas.

[0057] The sloping line for biocoal, with an energy density of 24 GJ / ton, indicates that biocoal contains approximately one-quarter to one-half less non-carbon elements such as oxygen (O) and hydrogen (H). Since a considerable amount of energy is contained in carbon, when oxygen (O) is removed, the energy density increases. However, the synthesis gas from biocoal with an energy density of 24 GJ / ton contains more carbon (C) and more tar than the biocoal mentioned above.

[0058] The sloping line for biocoal with an energy density of 30 GJ / ton shows that biocoal contains relatively small amounts of oxygen, O, and hydrogen, H, allowing for such a high energy density. However, Figure 2 also shows that syngas with an energy density of 30 GJ / ton contains a significant amount of carbon and a significant amount of tar.

[0059] In the process according to the invention, the tar remains with the synthesis gas and is burned to drive the process chamber 11a and to dry the biomass. Therefore, the tar does not require a separate process from the torrefaction device, but instead provides the energy to run the torrefaction device. The energy of the tar is usually derived from the carbon and hydrogen content of the synthesis gas.

[0060] The energy density of the biocoal depends, among other things, on the residence time during torrefaction of the dried biomass 22 in the treatment chamber 11a and the final temperature of the resulting biomass 22. For example, a residence time of 15 minutes in a treatment chamber 11a at about 500°C provides biocoal with an energy density of about 22 GJ / ton. A longer residence time at the same temperature, as shown by the time arrow, results in a higher energy density. At a residence time of 30 minutes, the energy density can be about 28 GJ / ton.

[0061] This also means that the amount of tar released from the biomass during torrefaction increases over time. In some embodiments, the first and / or second air feeds 15, 16 are controlled to adapt the supply of hot compressed air to the treatment chamber 11a and / or conduit 13 to the amount of tar released from the biomass during torrefaction in order to maintain the synthesis gas temperature above the condensation temperature of the tar. In some embodiments, biomass with different degrees of torrefaction is present in the treatment chamber 11a, and the treatment chamber 11a is arranged to be operated continuously such that the amount of tar released over time is essentially constant.

[0062] The torrefaction process in the torrefaction apparatus of the present invention will be described below. Note that although the following description is based on a batch of biomass, the process is continuous so that the generated synthesis gas can be used to heat the treatment chamber in the subsequent batch.

[0063] The biomass 21 is sent to the dryer 17 where it is dried with the aid of warm gas 26 from the oxidizer 12. The dryer 17 releases water 27 from the biomass 21 along with the warm gas 26. The dryer 17 provides dried biomass 22. The dried biomass 22 is sent through the inlet airlock 18 to the treatment chamber 11a.

[0064] In the treatment chamber 11a, the dry biomass 22 is heated to about 280°C-400°C so that it is torrefied and converted into biocoal 24 over time while releasing syngas 23. In various embodiments, the residence time of the dry biomass 22 in the treatment chamber 11a is 15 minutes to 30 minutes. In various embodiments, the temperature in the treatment chamber 11a is 400°C-550°C, preferably about 500°C. Once the dry biomass 22 has been converted into a given grade of biocoal 24, i.e. after a given residence time in the treatment chamber 11a, the biocoal 24 is discharged through the exit airlock 19. The biocoal 24 is then used for various possible applications, such as energy production, additive in steel production or permanent carbon storage.

[0065] A syngas 23 containing tars, H2, CH4 and / or CO is separated from the dry biomass 22 during torrefaction and passes through conduit 13. The syngas 23 in the treatment chamber 11a and conduit 13 is maintained at a temperature above the condensation temperature of the tars to prevent condensation of the tars. In various embodiments, the condensation temperature is about 400° C. In various embodiments, the temperature is maintained by preventing temperature exchange of the treatment chamber 11a and conduit 13 with the surroundings. In various embodiments, the temperature is maintained by burning a small amount of tar. In some embodiments, air is sent to the treatment chamber 11a and / or conduit 13 to burn the tars. In some embodiments, the air flow is controlled to maintain the temperature of the syngas 23 above the condensation temperature of the tars.

[0066] The syngas 23 is sent to the oxidizer 12. In various embodiments, air is sent to the oxidizer 12. In various embodiments, the flow of air sent to the oxidizer 12 is at least sufficient to combust all of the combustible components of the syngas 23. In various embodiments, the flow of air sent to the oxidizer 12 is adjusted to combust all of the combustible components of the syngas 23 and adjust the heat energy 25 provided from the oxidizer 12 to the treatment chamber 11a. In various embodiments, the flow of air sent to the oxidizer 12 is adjusted to provide warm gas 26 to the dryer 17 to dry the biomass 21. In various embodiments, the flow of air in the oxidizer 12 is adjusted to adjust the temperature of the treatment chamber 11a to between 400°C and 550°C, preferably about 500°C.

[0067] In various embodiments, the oxidizer air feed 14 regulates the air flow. In various embodiments, the air flow in the oxidizer 12 and / or the oxidizer air feed 14 is choked to regulate the air flow. In various embodiments, the air flow in the oxidizer 12 is regulated to regulate the temperature of the treatment chamber 11a. In various embodiments, the material that constitutes the treatment chamber 11a absorbs and dampens temperature fluctuations. This is particularly advantageous for biomass of varying quality that releases syngas of varying proportions during torrefaction.

[0068] Below are some examples of biomass input and biocoal production. Generally, biomass with a moisture content of about 10% has an energy content of approximately 16 GJ / ton to 19 GJ / ton. In the examples below, the flow of biomass is provided at 3100 kg / hour. This corresponds to a thermal power capacity of about 14.6 MW.

[0069] In a first example, the oxidizer 12 consumes approximately 3 MW in the form of synthesis gas to heat the treatment chamber 11a and dry the biomass. The treatment chamber 11a is heated to 500° C. The residence time of the biomass in the treatment chamber 11a is approximately 15 minutes. During the residence time, the biomass is heated to approximately 280° C. The energy yield is approximately 22 GJ / ton or 11.6 MW, which corresponds to approximately 79% of the energy contained in the original biomass.

[0070] In a second example, the oxidizer 12 consumes approximately 3.4 MW in the form of synthesis gas to heat the treatment chamber 11a and dry the biomass. The treatment chamber 11a is heated to 500° C. The residence time of the biomass in the treatment chamber 11a is approximately 20 minutes. During the residence time, the biomass is heated to approximately 300° C. The energy yield is approximately 24 GJ / ton or 11.2 MW, which corresponds to approximately 77% of the energy contained in the original biomass.

[0071] In a third example, the oxidizer 12 consumes approximately 4 MW in the form of synthesis gas to heat the treatment chamber 11a and dry the biomass. The treatment chamber 11a is heated to 500° C. The residence time of the biomass in the treatment chamber 11a is approximately 25 minutes. During the residence time, the biomass is heated to approximately 350° C. The energy yield is approximately 28 GJ / ton or 10.6 MW, which corresponds to approximately 72% of the energy contained in the original biomass.

[0072] In a fourth example, the oxidizer 12 consumes over 4 MW in the form of syngas to heat the treatment chamber 11a and dry the biomass. The treatment chamber 11a is heated to 500° C. The residence time of the biomass in the treatment chamber 11a is about 30 minutes. During the residence time, the biomass is heated to over 400° C. The energy yield is about 30 GJ / ton.

[0073] In all instances, the heat generated has sufficient energy to maintain the temperature of the reaction chamber while simultaneously drying wet biomass with a moisture content of 50% by weight at the inlet of the treatment chamber to a moisture content of about 10% by weight.

[0074] Note that for high energy densities of over 25 GJ / ton, bio-coal can be used for steel production. In these examples, up to 100 kW of syngas 23 is combusted in the process chamber 11a and / or conduit 13 to maintain the temperature of the syngas 23 above the condensation temperature of the tar.

[0075] Some examples of processing according to various aspects are shown in the table below.

[0076] [Table 1]

[0077] Here, "processing energy yield" refers to the energy retained in the biocoal after semi-carbonization, "product energy ratio" refers to the ratio of the energy density of the obtained biocoal to the input biomass, "input energy MJ / kg" refers to the energy density of the input biomass, "output energy MJ / kg" refers to the energy density of the obtained biocoal, and "mass yield" refers to the ratio of the mass of the obtained biocoal to the input biomass. The following claims as originally filed of this application are given as embodiments. [1] - A treatment chamber arranged for torrefaction of biomass; - an oxidizer arranged to heat the treatment chamber; and - a conduit for synthesis gas released from the biomass during the torrefaction process; A torrefaction apparatus comprising: the conduit is arranged to conduct the synthesis gas from the treatment chamber to the oxidizer; the oxidizer is configured to effect oxidation of the synthesis gas and release a power of at least 20% of the power contained in a maximum flow of biomass passing through the treatment chamber; Torrefaction device. [2] The torrefaction apparatus of [1], wherein the conduit is configured to maintain a synthesis gas temperature during operation higher than a condensation temperature of the synthesis gas from the treatment chamber. [3] The torrefaction apparatus of [2], wherein the synthesis gas temperature is maintained above 330°C and / or at least 50°C higher than the maximum temperature of the biomass in the treatment chamber. [4] The semi-carbonization apparatus according to any one of [1] to [3], wherein the conduit is insulated. [5] A torrefaction apparatus described in any of [1] to [4], wherein the conduit and / or the treatment chamber includes an air intake that enables controlled combustion of a portion of the synthesis gas. [6] The torrefaction apparatus described in any of [1] to [5], wherein the oxidizer is configured to provide oxidation that releases a power of at least 23%, 25% or 27% of the power contained in the maximum flow of biomass passing through the treatment chamber, and preferably, the oxidizer is configured to provide oxidation that releases a power of 36% or less or 40% or less of the power contained in the maximum flow of biomass passing through the treatment chamber. [7] The torrefaction apparatus according to any one of [1] to [6], wherein the oxidizer is configured to maintain the treatment chamber at 400°C to 550°C, preferably about 500°C. [8] The torrefaction apparatus according to any one of [1] to [7], wherein the oxidizer is arranged with an oxidizer air feed configured to maintain the temperature of the treatment chamber below 550°C, preferably below 500°C, by generating a flow of ambient dilution air toward the treatment chamber. [9] The torrefaction apparatus according to [7] or [8], wherein the temperature rating of the treatment chamber is less than 600°C, preferably 550°C or less.

[10] The torrefaction apparatus according to any of [1] to [9], wherein the treatment chamber comprises a supply element, a conveying element and / or a distribution element configured to retain a specific amount of biomass within the treatment chamber for at least 15 minutes, preferably at least 30 minutes.

[11] A torrefaction apparatus as described in any of [1] to

[10] , wherein the treatment chamber is configured to minimize natural air exchange between the contents and the surrounding air, the treatment chamber preferably includes an inlet having an airlock and an outlet having an airlock, the biomass is transported through the inlet, the treatment chamber and the outlet, and the treatment chamber is preferably maintained at a pressure lower than the surrounding air pressure.

[12] The synthesis gas is a mixture of tar, H 2 , C.H. 4 and / or CO, and the oxidizer is preferably configured to combust at least a portion of the tar.

[13] - Sending the biomass to the processing room; - heating the biomass in the treatment chamber to pyrolyze the biomass and release a syngas from the biomass, the syngas containing at least 20% of the power contained in the flow of the biomass; and - oxidizing the synthesis gas to heat the biomass in the treatment chamber; The torrefaction method includes the steps of:

[14] The torrefaction method according to

[13] , wherein a certain amount of biomass is kept in the treatment chamber for at least 15 minutes, preferably at least 30 minutes.

[15] The torrefaction method of

[13] or

[14] , wherein the temperature of the synthesis gas is maintained above 330°C and / or at least 50°C higher than the maximum temperature of the biomass in the treatment chamber.

[16] The torrefaction method according to

[15] , wherein the synthesis gas is mixed with a controlled flow of air, the air being preferably heated.

Claims

1. - a treatment chamber arranged for torrefaction of biomass; an oxidizer arranged to heat the treatment chamber, and - a conduit for the synthesis gas released from the biomass during the torrefaction process; A torrefaction apparatus comprising: the conduit is arranged to conduct the synthesis gas from the treatment chamber to the oxidizer; and the oxidizer is configured to effect oxidation of the synthesis gas to release a power of at least 27% of the power contained in a maximum flow of biomass through the treatment chamber. Torrefaction device.

2. The torrefaction apparatus of claim 1 , wherein the conduit is configured to maintain a syngas temperature during operation above a condensation temperature of the syngas from the treatment chamber.

3. 3. The torrefaction apparatus of claim 2, wherein the synthesis gas temperature is maintained above 330° C. and / or at least 50° C. higher than the maximum temperature of the biomass in the treatment chamber.

4. The torrefaction apparatus according to any one of claims 1 to 3, wherein the conduit is insulated.

5. Torrefaction apparatus according to any one of claims 1 to 4, wherein the conduit and / or the treatment chamber comprises an air intake allowing controlled combustion of a portion of the synthesis gas.

6. The torrefaction apparatus according to any one of claims 1 to 5, wherein the oxidizer is configured to maintain the treatment chamber at 400°C to 550°C.

7. 7. The torrefaction apparatus according to any one of claims 1 to 6, wherein the oxidizer is arranged with an oxidizer air feed, the oxidizer air feed being configured to maintain a temperature of the treatment chamber below 550°C by generating a flow of ambient dilution air towards the treatment chamber.

8. 8. The torrefaction apparatus according to claim 6 or 7, wherein the temperature rating of the treatment chamber is less than 600°C.

9. 9. The torrefaction apparatus according to claim 1, wherein the treatment chamber comprises a supply element, a conveying element and / or a distribution element configured to retain a certain amount of biomass in the treatment chamber for at least 15 minutes.

10. 10. The torrefaction apparatus according to any one of claims 1 to 9, wherein the treatment chamber is configured such that natural air exchange between the contents and the surrounding air is minimized.

11. The synthesis gas is ２ , C.H. ４ The torrefaction apparatus according to any one of claims 1 to 10, further comprising:

12. - sending the biomass to a treatment room; - heating the biomass in the treatment chamber to pyrolyze the biomass and release a synthesis gas from the biomass, the synthesis gas containing at least 27% of the power contained in the flow of the biomass; and - oxidizing said synthesis gas to heat said biomass in said treatment chamber; The torrefaction method includes the steps of:

13. 13. The torrefaction method of claim 12, wherein the amount of biomass is held in the treatment chamber for at least 15 minutes.

14. 14. The torrefaction process according to claim 12 or 13, wherein the temperature of the synthesis gas is maintained above 330°C and / or at least 50°C higher than the maximum temperature of the biomass in the treatment chamber.

15. 15. The torrefaction process according to claim 14, wherein said synthesis gas is mixed with a controlled flow of air.

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