WO2011041880A1

WO2011041880A1 - Method and apparatus for producing oil-impregnated biomass products

Info

Publication number: WO2011041880A1
Application number: PCT/CA2010/001304
Authority: WO
Inventors: Mark A. Lowe
Original assignee: Southern Biomass, Llc
Priority date: 2009-10-05
Filing date: 2010-08-30
Publication date: 2011-04-14
Also published as: CA2686099A1; WO2011041881A1

Abstract

A method for the production of a torrefied biomass product from a particulate biomass material, comprising treating the biomass material with a bio-liquid selected from an animal fat and plant oil at an effective temperature to provide the torrefied product. The bio-oil is selected from plant oil and animal fat, preferably, vegetable oil, such as, canola or soybean oil. The biomass material is, preferably, a hardwood, softwood or wood bark.

Description

METHOD AND APPARATUS FOR PRODUCING OIL-IMPREGNATED BIOMASS

PRODUCTS

FIELD OF THE INVENTION

[0001] This invention relates to torrefaction processes for the production of torrefied products, particularly, wood, bark and agricultural biomass using plant and animal oils, an apparatus for carrying out said processes.

BACKGROUND OF THE INVENTION

[0002] Torrefaction is the process of turning biomass material into a charcoal-like state by super-heating the material in a non-oxygen environment. In the art, it is generally anticipated that biomass, or more particularly, torrefied biomass will be an important source of energy as fossil fuels become less appealing due to the impact they have on the environment or as supply dwindles. Biomass, on the other hand, is renewable, reduces significantly fewer greenhouse gasses and is widely available. Raw biomass products generally have a low density resulting in inefficient storage and shipping and otherwise include a low energy density. Thus, the amount of biomass required to be effective as a fuel has hampered their widespread use.

[0003] More recently, densification and torrefaction processes have been used to produce a higher quality biomass. Densification involves a commercial process that converts biomass into pellets, logs, or other easily useable shapes. Unfortunately, densification processes require the use of costly machinery requiring large amounts of energy to run. Prior art torrefaction processes have involved the use of hot gases to subject the biomass to a heat sufficient to increase the mass density of the biomass and render the now torrefied biomass waterproof. Prior art torrefied biomass generally resulted in a mass energy density of between 8000 to 10000 Btu/lb). More recent improvements to torrefaction processes have allowed for an energy density of up to 1 1000 Btu/lb. As will be appreciated by a person skilled in the art, an increased energy density will be required for more widespread use of torrefied biomass products, and accordingly , there is a need in the art for an improved torrefaction process that can produce an improved biomass product having a greater mass energy density.

[0004] Furthermore, prior art torrefaction processes are otherwise inefficient, resulting in the loss of large amounts of biomass material SUMMARY OF THE INVENTION

[0005] The present invention provides a more efficacious torrefaction process of producing a biomass product of enhanced heat value.

[0006] Accordingly, in one embodiment of the invention there is provided a method for the production of a torrefied biomass material from a particulate biomass material, comprising treating said material with a bio-liquid selected from an animal fat and plant oil prior to heating said biomass to a temperature suitable to torrefy the biomass. In this manner, the biomass material is treated with, impregnated with, or otherwise mixed with a bio-liquid such that torrefaction is carried out on the oil-treated biomass. Preferably, the treating step is one of spraying and mixing the bio-liquid with the particulate biomass material, submerging the particulate biomass material in the bio-liquid, or liquid drying the biomass material with the bio- liquid. The bio-liquid may comprise a vegetable oil, a soybean oil, or a canola oil.

According to one aspect of the invention, the treating comprises liquid drying with the bio-liquid at a temperature between 150 °C and 250 °C, and more preferably at approximately 200 °C.

[0007] According to another embodiment of the invention, there is provided a method for the production of a torrefied wood product from a wood source, the method including the steps of subjecting the wood source to mechanical means to produce particulate wood, treating the particulate wood with a bio-liquid selected from an animal tallow and plant oil, heating the particulate wood at an effective temperature for an effective period of time to effect torrefaction, removing the torrefied wood from excess of the bio-liquid, and collecting the now torrefied wood product.

[0008] According to one aspect of this embodiment, the treating step includes liquid drying the particulate wood. Preferably, during liquid drying, the bio-liquid is maintained at a temperature between 150 °C and 250 °C, and more preferably, at a temperature of approximately 200 °C.

[0009] According to another aspect of this embodiment, the mechanical means is a chipper to produce particulate wood having dimensions of about 6 mm to 2 cm. Alternatively, the mechanical means may comprise a mill to produce milled particulate wood. The method may then further include the steps of treating the milled particulate wood with a first bio-liquid selected from an animal fat and plant oil to produce a bio-liquid-milled particulate wood admixture, and transforming the wood admixture in a pellet mill extruder to produce pellets having dimensions of about 6 mm to 2 cm, prior to carrying out the treating, torrefying and cooling steps identified above.

[0010] Preferably, the effective temperature to effect torrefaction is greater than 200°C, and more preferably, is in the range of 240°C to 375°C.

[0011] The biomass material may be selected from wood material, cellulosic agricultural material, peat moss and industrial sludge. The wood material may further be in the form of chips, pellets or bark. Preferably, the torrefied biomass product has a vegetable oil content of at least 1% w/w, and more preferably between 4 to 12% w/w, where w/w refers to wet weight.

[0012] Preferably, the bio-liquid is filtered throughout the process to remove any soluable materials.

[0013] According to another aspect of the invention, the method further comprises cooling the torrefied wood product at least in part with condensed steam obtained from the liquid drying step. As will be appreciated by one skilled in the art, the heating step results in the release of gases contained in the particulate wood product, and the method optionally further includes the step of recovering the gases and using the gases to supplement energy required to maintain the bio-liquid at the temperature required to treat the bio-liquid.

[0014] According to another embodiment of the invention, there is provided a system for carrying out the above-identified methods, the system including storage means for storing a raw biomass product, treating means for treating the raw biomass product with a heated bio-liquid selected from a plant oil and an animal tallow; and, a torrefaction chamber for effecting torrefaction of the raw biomass product to produce a torrefied biomass product. The storage means may be a hopper, bin, warehouse, transport vehicle, or any type of space, apparatus or device capable of storing the raw biomass product. The system may further include cooling means for cooling said torrefied biomass product. The cooling means may be a cooling tower. [0015] According to one aspect of this embodiment, the system further includes mill means to reduce the raw biomass product to a raw particulate biomass product.

[0016] According to another aspect of the invention, the treating means comprises one of a bio-liquid bath and a bio-liquid spray. According to another aspect, the treating means is a liquid dryer. The liquid dryer may be filled with the bio-liquid and produces condensed steam as moisture leaves the raw biomass product during the liquid drying process. Optionally, this condensed steam may be used to cool the torrefied biomass product in the cooling tower.

[0017] According to another aspect of the invention, the system may include a boiler unit fo heating the bio-liquid. Preferably, during torrefaction, the torrefaction chamber release gases contained in the raw biomass product while effecting torrefaction and these gases are supplied to the boiler unit to supplement the energy required to heat the bio-liquid.

[0018] According to another embodiment of the invention, there is provided a method for the production of a torrefied biomass material from a raw biomass material, comprising heating sthe raw biomass material material with a bio-liquid selected from an animal tallow and plant oil, at a temperature sufficient to effect torrefaction of the raw biomass material.

[0019] Surprisingly, it has been discovered that the torrefaction process according to the invention is effected in a relatively short period of time, dependent on the temperature and nature and particle size of the biomass material. For example, times of less than 10 minutes can be readily achieved. Pinewood pellets can be torrefied with canola or soybean oils at about 240°C in about 6 minutes. Pine and a hardwood was torrefied with canola oil at about 280°C within 6 minutes. At a temperature of about 320°C in canola oil, pine wood was completely torrefied in about 1 minute.

[0020] In a further aspect, the invention provides a method for the production of a torrefied wood product from a wood source, said method comprising

(i) subjecting said wood source to mechanical means to produce particulate wood; (ii) heating said particulate wood in a bio-liquid selected from an animal fat and plant oil at an effective temperature for an effective period of time to effect torrefaction and produce torrefied wood;

(iii) removing said torrefied wood from excess said bio-liquid; and

(iv) collecting said torrefied wood product.

[0021] In a further aspect, the invention provides, a method as hereinabove defined wherein said mechanical means comprises a chipper to produce particulate wood having dimensions created by conventional wood chipping apparatus.

[0022] In a further aspect, the invention comprises a pelletizing method that virtually eliminates fine, wood particles or dust that would otherwise be created after the pellets are extruded, because the bio-oil creates a binding agent for the material that precludes the creation of these dust particles during the pelleting process.

[0023] Thus, in yet a further aspect, the invention provides, a method as hereinabove defined wherein said mechanical means comprises a mill to produce milled particulate wood; and further comprising

(v) treating said milled particulate wood with a first bio-liquid selected from an animal fat and plant oil to produce a bio-liquid-milled particulate wood admixture;

(vi) treating said wood admixture in a pellet mill extruder to produce pellets having dimensions; and effecting steps (ii), (iii) and (iv) as defined in claim 1 wherein said pellets constitute said particulate wood.

[0024] Preferably, the pellets have a particle size of about 4-6 mm in diameter and 1-2 cm in length. [0025] In a yet further aspect, the invention provide a process for producing a torrefied particulate biomass material comprising at least 4-12% w/w vegetable oil.

[0026] According to another embodiment of the invention, there is provided method for the production of a torrefied biomass material from a raw biomass material, comprising treating said material with a bio-liquid selected from an animal tallow and plant oil and heating said treated biomass material at a torrefaction temperature to provide said torrefied biomass material.

[0027] Thus, it has been have found that torrefaction of biomass material with a bio-oil selected from plant oils and animal fats, preferably, vegetable oil, gives a BTU boost compared to traditional torrefaction methods because of the penetration of the oil through the strata of biomass material, preferably, wood fibre.

[0028] Vegetable oil provides an anaerobic oxygen-free super heated environment to allow torrefaction. Further, by using new or used vegetable oil in the method of the invention, torrefied pellets maintain a low pollution emission level, are water resistant, and reduced organic materials found in non-torrefied biomass. Advantageously, the pellets, according to the invention, can be shipped and stored safely because the gases released by normal wood pellets are not present in consequence of the removal of the organics in the present torrefaction process. Further, the pellets can be used for energy production in co-fired coal burning facilities due to their extremely low moisture level and similar BTU values. The torrefied pellets can be crushed to dust and blown into existing coal fired furnaces with minimal changes to the furnace and coal feeding process being needed. Torrefying methods using hot oil versus traditional hot gases allow the biomass material to retain more mass, since traditional torrefaction methods experienced large volume loss due to the removal of carbon molecules. During hot oil torrefaction, the carbon molecules are sequestered and maintain more mass.

[0029] The pelletized product as hereinabove defined can be used to generate heat in residential or commercial pellet stoves and/or other industrial uses, such as, energy creation or bulk heating applications.

[0030] Preferably the torrefied particulate biomass material is burnt in admixture with particulate coal. [0031] In a further aspect, the invention provides a torrefied biomass material as hereinabove defined for use as a soil modifier.

[0032] The world is currently focused on the global warming crisis and the development of carbon neutral fuel sources. The present invention not only produces a carbon-neutral hybrid energy pellet, it also diverts waste agricultural and/or forestry materiel from the waste stream and creates a product that can be used for energy production. Using bio-oils such as those derived from plants and animals, e.g. new vegetable oil, refined, used vegetable oil, animal fats and the like. The method according to the invention allows for virtually total use of the oil. This is in contrast to historical usage for biodiesel production wherein conventional use utilizes only 60% of the total weight of material because the unwanted soaps and other delirious substances arc discarded.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order that the invention may be better understood, preferred embodiments will now be described, by way of example only, with reference to the accompanying drawings, wherein

[0034] Figure 1 is a block diagram of a torrefaction process according to one embodiment of the invention;

[0035] Figure 2 is a block diagram of an alternative torrefaction process according to the invention; and wherein the same numerals denote like parts.

[0036] Figure 3 is a block diagram of a third embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0037] Referring now to Figure 1, there is shown a system 10 for carrying out a torrefaction process according to one embodiment of the invention. The system 10 is preferably used to produce an improved torrefied biomass product, described in further detail below. As will be understood by those skilled in the art, the system 10 provides for exemplary machinery and other components for carrying out the process of the invention, however, the invention is not limited to such machinery and other components, where similar, analogous, or other functionally equivalent equipment may be used.

[0038] In the illustrated embodiment of Figure 1, a conditioning chamber 12 is provided functionally linked by a conveyor 14 to a mill chipper 16, which is linked to a secondary conditioner 18 by conveyor 20. Above conditioner 18 is located a spray tank 22 containing a bio- liquid 24. Bio-liquid 24 is preferably, one of a vegetable oil, a plant oil, an animal fat, an combinations thereof. Particular examples, include, but are not limited to canola oil, soybean oil, and animal tallow. Conditioner 18 is connected to a screw conditioner 26 which is connected to a torrefaction tank 28. A screen unit 32 is connected in-line with the torrefaction tank 28 to separate now torrefied biomass from any excess oil. The torreified biomass exiting the screen unit 32 is collected on conveyor 34 and transferred to a cooling tower 32. A packaging unit 36 is provided at an exit of cooling tower 32.

[0039] In operation, wood, or other, biomass material is initially fed to conditioning chamber 12 by conveyor 14 and then to chipper 16 where the material is reduced to less than 6 mm in diameter and a maximum length of 10 cm. The thus reduced material is transferred on conveyor 20 to secondary conditioner 18 and treated with the bio-liquid 24 at a temperature of about 240°C from spray tank 22. The oil sprayed chips are mechanically mixed in screw conditioner 26 and subsequently submerged and torrefied in torrefaction tank 28 at a temperature of at least 240°C for a sufficient period of time to effect torrefaction. Provided below are examples of what constitutes a sufficient time for various materials and oils used. A temperature of between 240°C-300°C is preferred.

[0040] The torrefied biomass is removed from tank 28 and filtered at screen 32 to remove any excess oil. The torrefied biomass is then transferred to tower 32 via conveyer 34 to cool and harden and is subsequently packaged in unit 36 in bulk or in bags. The excess oil may be recovered and routed back to the spray tank 22.

[0041] It will be understood by those skilled in the art that the terms linked to, connected to, functionally attached to, and other terms used in describing the systems for carrying out the process according to the invention, to indicate a connection between certain functional elements in the systems are not limited as such. That is, any arrangement of components as described and used to carry out the functions earlier described may be used, and connected to each other as would be known to a person skilled in the art. Furthermore, various means of moving biomass between the functional elements may be employed and are not limited to the conveyors or augering means described in these preferred embodiments.

[0042] Fig. 2 shows a system 50 for carrying out a torrefaction process according to an alternate embodiment of the invention. In the illustrated embodiment of Figure 2, a conditioning chamber 12 is provided functionally linked by a conveyor 14 to a hammer mill 52, which is linked to a secondary conditioner 18 by conveyor 20. Above conditioner 18 is located a spray tank 22 containing a bio-liquid 24. Bio-liquid 24 is preferably, one of a vegetable oil, a plant oil, an animal fat, an combinations thereof. Particular examples, include, but are not limited to canola oil, soybean oil, animal tallow. Conditioner 18 is connected to a screw conditioner 26 which is connected to a torrefaction tank 28, with a pellet mill extruder therebetween. A screen unit 32 is connected in-line with the torrefaction tank 28 to separate now torrefied biomass from any excess oil. The torreified biomass exiting the screen unit 32 is collected on conveyor 34 and transferred to a cooling tower 32. A packaging unit 36 is provided at an exit of cooling tower 32.

[0043] The process of system 50 operates generally as the system of 10 of Figure 1, however, the hammer mill 52 reduces the biomass material to less than 6 mm in diameter; and extruder 54 produces pellets of about 6 mm to 10 mm in diameter.

[0044] The process described in Figure 2 provides the torrefaction of chipped biomass before pelletization to enable the removal of the traditional drying procedure currently being used to dry biomass so that pellets may be extruded.

[0045] Referring now to Figure 3, there is shown a system 80 for carrying out a torrefaction process according to a further embodiment of the invention. In the system 80, a conveyor 82 is provided to load the raw biomass material into a hopper 84. Hopper 84 is connected to a liquid dryer 86, having a hot bio-liquid 88 therein. Bio-liquid 88 may comprise any of the bio-liquids described throughout this specification. Preferably, liquid dryer 86 has an open top. The liquid dryer 86 is functionally attached to a torrefaction chamber 94, which is connected to a cooling chamber 88. Further processing equipment 90 is provided following the cooling chamber 88. A hot oil boiler 92 is attached to the torrefaction chamber 94 to heat the bio-liquid to a temperature effective to initiate torrefaction, as will be described below. An auger is provided to assist in the removal of the biomass material from the liquid dryer 86.

[0046] In operation, the system 80 carries out a torrefaction process whereby biomass flows from the hopper 84 to the liquid dryer 86 where the raw biomass is bathed, sprayed, or otherwise treated with one of the aforementioned bio-liquids. Preferably, the bio-liquid in the liquid dryer 86 is held at a temperature of between 150 °C and 250 °C, and more preferably, at a constant temperature of 200 °C. It has been discovered that this temperature range allows a majority, or all of the moisture to be biled off. The moisture leaves the dryer 86 as steam, that is preferably re-used, as described in more detail below.

[0047] Next, the biomass material is augered out and directed towards the torrefaction chamber 94. Preferably, the torrefaction chamber maintains a temperature of between approximately 240 °C and 375 °C. Preferably, filters (not shown) are provided to filter the oil, for example, to remove any soluble material produced during torrefaction. As the biomass undergoes torrefaction, gasses are released from the biomass. These gases are preferably recovered by vacuum and pumped to the hot oil boiler 92 to supplement the energy required to head the bio-liquid. Recycling the excess released gasses from the torrefaction chamber 94 as an energy source for the boiler 92 provides for increased energy efficiency of the system.

[0048] Once torrefaction is complete, the biomass is augered to a cooling chamber 88that contains condensed steam. Optionally, the condensed steam in the cooling chamber 88 is obtained as a by-product from the liquid dryer 86 as the biomass is dried earlier in the process. Once the biomass is cooled, it is further processed into end-use products, such as fuel pellets or briquettes, after which they are packaged for transport.

EXAMPLE 1

[0049] Table 1 gives the results for two oil torrefied wood chips referred to as Light and

Dark.

LIGHT

[0050] Prepared by torrefying pine wood pellets in canola oil at 240°C for 6 minutes. DARK

[0051] Prepared by torrefying pine wood pellets in soybean oil at 280°C for 6 minutes.

TABLE 1

Light Dark

Sample ID (Log-in #7441/1) (Log-in #7442/2)

Moisture Content(Wet Basis)% 3.51 0.72

Moisture Content(Dry Basis)% 3.64 0.73

Ash% 0.18 0.18

Higher Heating Value BTU/lb bone dry 1 1783 12337

Higher Heating Value BTU/lb at MC received 1 1369 12247

Procedures:

Moisture Content— ASTM E871-82 Ash Content— ASTM Dl 102-84 Heating Value— ASTM E71 1-87

EXAMPLE 2

[0052] In additional experiments, the following tests were performed and the results presented. [0053] The first test was heating canola oil to 200°C and putting pine wood pellets in the oil to expel moisture. The moisture level went from 7.01% down to 1.4% after 4 minutes in submersion. The pellets were removed and tested for BTU value.

[0054] The second test was heating canola oil to 280°C and placing the wood pellets that had been previously exposed to the 200°C oil into the higher temperature oil. The pellets were submerged for an additional 4 minutes. The moisture level was checked and a level reduction from 1.4% to a new low level of 1.2% was experienced. The BTU level was checked and has increased from 8098 btu/pound (original at 7.01%) to a level of 9299 btu/pound.

[0055] The second set of tests were completed using the same procedure as above, however, wherein wood pellets made of a 80% hardwood and 20% pine mixture were used.

[0056] The control pellets received were 7.04% moisture with a btu level of 8167 btu/pound. After the process a moisture value of 1.63% and a 9591 btu/pound level was achieved.

[0057] During the experiment the pellets were observed to first turn light brown in color at the 200°C heat level then dark brown to black as they were torrefaction was experienced during the 280°C to 320°C heat level.

[0058] Both types of pellets were observed to maintain the same physical characteristics for hardness and durability after the torrefaction process. It was observed during the cooling process the residual oil on the pellets was absorbed by the pellet and a miniscule film of oil was left present.

[0059] When the pellets were broken apart it was noted that the material had been torrefied throughout the strata of the pellet.

[0060] A test to determine if the torrefied pellets would re-absorb the moisture lost was effected by submersion in water. After a lengthy period of time of submersion the pellets were observed and noted that they did not reabsorb moisture where normal pellets re-absorb and crumble in minutes. EXAMPLE 3

Test Method

[0061] An analysis was conducted on burn rate and energy content of vegetable oil - heat treated wood pellets. The main purpose of this analysis was to determine how much longer the heat treated pellets burned compared to untreated conventional wood pellets. Also included in this analysis was a visual comparison of the residue left behind after burning heat treated and unheat-treated wood pellets. Two different heat treated samples of wood pellets and two samples of untreated pellets from the same bags were used for heat treatment.

[0062] An additional object was to determine the heat value (Btu/lb) of the heat treated pellets according to standard test method ASTM E71 1-87 and the moisture content according to standard test method ASTM E871-82.

[0063] Two groups of oil torrefied pellets were analyzed. The first group of pellets consisted entirely of softwood, while the second group, called mixed wood, was made up of 80 percent hardwood and 20 percent softwood. To make a valid comparison, the two groups were compared to untreated pellets of the same type.

[0064] A pellet stove, Enviro EFllli Bay™, was provided with thermal couple temperature sensors to monitor temperatures at the following locations, (1) air into heat exchanger (stove supply air), (2) out of heat exchanger (room heat), (3) combustion air (air to firebox) and (4) combustion exhaust to stack.

[0065] The first step was to run some pellets through the stove to warm it up. Next, the feed rate was set at a constant rate and a 0.50 kg sample of untreated softwood pellets was passed through the stove and the difference between the average temperature out of the stove heat exchanger and the average temperature of the stove supply air was calculated. Also noted was the run Lime to bum the 0.50 kg sample. Next, a 0.50 kg sample of heat treated softwood pellets was burned and the run time noted. In this case, the feed rate was adjusted to maintain the same temperature differential as was noted for the first run. By using this approach, a direct comparison of the burn times between the heat treated and untreated wood pellets can be made since the sample mass and temperature differential were held constant. [0066] The same method was followed for the mixed wood group as is described above for the softwood group.

Results

[0067] Table 1 summarizes the results comparing the burn times of the heat treated versus the untreated wood pellets for both the softwood and mixed wood groups.

[0068] Table 1 - Results summary of wood pellet burn test (sample size = 0.50 kg)

Pellet type Run time, min Temp, °C

Softward, untreated 46 43

Softwood, heat treated 60 42

Mixed wood, untreated 54.5 40

Mixed wood, heat treated 65 40

¹ Temperature differential between the average temperature out of the stove heat exchanger and the average temperature of the stove supply air.

[0069] Based on the results given above, the heat treated softwood pellets burned 30 percent longer than the untreated softwood control. The heat treated mixed wood pellets burned 19 percent longer than the untreated mixed wood control. It is noted that the temperature differential of the heat treated softwood group was one degree cooler than the control, which would result in a slight increase in the burn time.

[0070] Visual assessment of the residue after burning revealed no apparent difference between the heat treated and untreated pellets for both the softwood and mixed wood groups.

[0071] The results from the heat value tests are given in Table 2 for all four groups of pellets tested.

[0072] Table 2 - Heat value (Btu/lb) test results Pellet type As received moisture Higher Heating Value, BTU/lb content (MC), %^l Oven dry [2] (¾ as received MC

Softward, untreated 7.01 8.665 8.098

Softwood, heat treated 1.70 9.455 9,299

Mixed wood, untreated 7.04 8.742 8.167

Mixed wood, heat treated 1.63 9.750 9,591

^{1 1} Moisture content calculated on an oven-dry basis.

^[2] Higher heating value test conducted on oven dried material. Higher heating value @ as received moisture content calculated from oven dry and as received moisture content result.

[0073] Based on these results the oven dry heating value of the heat treated softwood pellets was 9 percent higher than the untreated softwood pellets. The oven dry heating value of the heat treated mixed wood pellets was 1 1.5 percent greater than the untreated mixed wood pellets. The as received moisture content of the heat treated pellets was over four times lower than that of the untreated control for both softwood and mixed wood groups. The energy needed to dissipate the moisture in the pellets is accounted for in the '@ as received MC heating values. The heating value '@ as received MC of the heat treated softwood pellets was 15 percent greater than the untreated softwood pellets. The heating value '@ as received MC of the heat treated mixed wood pellets was 17 percent greater than the untreated mixed wood pellets.

Conclusion

[0074] The following conclusions are based on the findings from this analysis which consider the results from one set of tests, as follows:

• The heat treated softwood pellets and mixed wood pellets burned at least 19 percent longer than the untreated wood pellets they were made from. Based on a visual assessment, there was no apparent difference in the amount of residue after burning between the heat treated and untreated pellets for both the softwood and mixed groups.

The 'as received' moisture content of the heat treated softwood and mixed wood pellets was 4.1 and 4.3 times lower than that of the untreated softwood and mixed wood control groups, respectively.

The higher heating value (@ as received moisture content) of the heat treated softwood pellets was 15 percent greater than the heat value of the untreated softwood pellets.

The higher heating value (@ as received moisture content) of the heat treated mixed wood pellets was 17 percent greater than the heat value of the untreated mixed wood pellets.

EXAMPLE 4

[0075] Pine wood chips treated in canola oil at 320°C produced total torrefaction within

1 minute.

EXAMPLE 5

[0076] A wood carbon sample produced in accordance with the process illustrated and described with reference to Figure 3, above. The raw wood biomass material was liquid dried in animal tallow before being subjected to a torrefaction process. The resultant torrefied wood carbon was analyzed in accordance with the aforementioned ASTM test methods. The sample tested showed the following results:

AS RECEIVED DRY BASIS

TOTAL MOISTURE % 5.26

ASH % 1.14 1.20

VOLATILE MATTER % 57.07 60.24

FIXED CARBON % 36.53 38.56

SULFUR % 0.21 0.22

GROSS BTU/LB 13,963 14,738 [0077] As shown, raw wood biomass material, when liquid dried with an oil, prior to torrefaction results in an increased heat energy measurement. Various other experiments have shown an increase to between 13500-14000 btu/lb.

[0078] Thus, it has been have found that torrefaction of biomass material with a bio-oil selected from plant oils and animal fats, preferably, vegetable oil, gives a BTU boost compared to traditional torrefaction methods because of the penetration of the oil through the strata of biomass material, preferably, wood fibre.

[0079] Vegetable oil provides an anaerobic oxygen-free super heated environment to allow torrefaction. Further, by using new or used vegetable oil in the method of the invention, torrefied pellets maintain a low pollution emission level, are water resistant, and reduced organic materials found in non-torrefied biomass. Advantageously, the pellets, according to the invention, can be shipped and stored safely because the gases released by normal wood pellets are not present in consequence of the removal of the organics in the present torrefaction process. Further, the pellets can be used for energy production in co-fired coal burning facilities due to their extremely low moisture level and similar BTU values. The torrefied pellets can be crushed to dust and blown into existing coal fired furnaces with minimal changes to the furnace and coal feeding process being needed. Torrefying methods using hot oil versus traditional hot gases allow the biomass material to retain more mass, since traditional torrefaction methods experienced large volume loss due to the removal of carbon molecules. During hot oil torrefaction, the carbon molecules are sequestered and maintain more mass.

[0080] Although this disclosure has described and illustrated certain preferred embodiments of the invention, it is to be understood that the invention is not restricted to those particular embodiments. Rather, the invention includes all embodiments which are functional or mechanical equivalence of the specific embodiments and features that have been described and illustrated.

Claims

A method for the production of a torrefied biomass material from a raw biomass material, comprising treating said material with a bio-liquid selected from an animal tallow and plant oil and heating said treated biomass material at a torrefaction temperature to provide said torrefied biomass material.

A method according to claim 1, wherein said treating is selected from the group comprising spraying, submerging and liquid drying.

A method according to claim 1, wherein said treating comprises liquid drying with said bio-liquid at a temperature between 150 °C and 250 °C.

A method according to claim 3, wherein said temperature is approximately 200 °C.

A method according to any one of claims 1 to 4, wherein said bio-liquid comprises one of a vegetable oil, a soybean oil and a canola oil.

A process for the production of a torrefied wood product from a wood source, said method comprising

(i) subjecting said wood source to mechanical means to produce particulate wood;

(ii) treating said particulate wood with a bio-liquid selected from an animal tallow and plant oil;

(iii) heating said particulate wood at an effective temperature for an effective period of time to effect torrefaction;

(iv) removing said torrefied wood from excess said bio-liquid; and

(v) collecting said torrefied wood product.

A process according to claim 6, where said treating comprises liquid drying.

A process according to claim 7, wherein said bio-liquid is maintained at a temperature between 150 °C and 250 °C in said liquid drying step.

9. A process according to claim 8, wherein said temperature is approximately 200 °C.

10. A process as claimed in claim 6 wherein said mechanical means comprises a chipper to produce particulate wood having dimensions of about 6 mm to 2 cm.

1 1. A process as claimed in claim 6 wherein said mechanical means comprises a mill to produce milled particulate wood; further comprising

(vi) treating said wood admixture in a pellet mill extruder to produce pellets having dimensions of about 6 mm to 2 cm; and effecting steps (ii), (iii) and (iv) as defined in claim 6 wherein said pellets constitute said particulate wood.

12. A process as claimed in any one of claims 6 wherein said effective temperature is greater than 200°C.

13. A process as claimed in claim 12 wherein said effective temperature is selected from the range of 240°C to 375°C.

14. A process as claimed in any one of claims 1 to 13 wherein said biomass material is selected from wood material, cellulosic agricultural material, peat moss and industrial sludge.

15. A process as claimed in claim 14 wherein said wood material is in the form of chips, pellets or bark.

16. A process as claimed in any one of claims 6 to 15 wherein said torrefied biomass product has a vegetable oil content of at least 1% w/w.

17. A process as claimed in claim 16 wherein said torrefied biomass product has a vegetable oil content selected from 4-12% w/w.

18. A process according to claim 8, further comprising filtering said bio-liquid before any one of steps (ii) and (iii).

19. A process according to any one of claims 8 to 18, further comprising cooling said torrefied wood product.

20. A process according to claim 7, further comprising cooling said torrefied wood product at least in part with condensed steam obtained from said liquid drying step.

21. A process according to any one of claims 8 and 9, wherein said heating step results in the release of gases contained in said particulate wood product, said method further comprising the step of recovering said gases and using said gases to supplement energy required to maintain said bio-liquid at said temperature.

22. A system for producing a torrefied biomass product comprising:

(a) storage means for storing a raw biomass product;

(b) treating means for treating said raw biomass product with a heated bio- liquid selected from a plant oil and an animal tallow; and,

(c) a torrefaction chamber for effecting torrefaction of said raw biomass product to produce a torrefied biomass product.

23. A system according to claim 22, further comprising cooling means for cooling said torrefied biomass product.

24. A system according to claim 22, further comprising mill means to reduce said raw biomass product to a raw particulate biomass product.

25. A system according to any one of claims 22 to 24, wherein said treating means comprises one of a bio-liquid bath and a bio-liquid spray.

26. A system according to claim 23, wherein said treating means comprises a liquid dryer.

27. A system according to claim 26, wherein said liquid dryer is filled with said bio-liquid and produces condensed steam as moisture leaves said raw biomass product.

28. A system according to claim 26, wherein said condensed steam is used to cool said torrefied biomass product in said cooling means.

29. A system according to any one of claims 22 to 28, further comprising a boiler unit for heating said bio-liquid.

30. A system according to claim 29, wherein said torrefaction chamber release gases contained in said raw biomass product while effecting torrefaction and said gases are supplied to said boiler unit to supplement the energy required to heat said bio-liquid.

31. A method for the production of a torrefied biomass material from a raw biomass material, comprising heating said raw biomass material material with a bio-liquid selected from an animal tallow and plant oil and heating at a temperature sufficient to effect torrefaction of said raw biomass material.

32. A method according to claim 31, wherein said temperature is selected from the range of 240°C to 375°C.

33. A method according to any one of claims 1 to 5 and 31, wherein saw raw biomass material is selected from the group comprising hardwood chips, softwood chips, pellets, bark, cellulosic waste agricultural materials, peat moss, and industrial sludge.

34. A process according to any one of claims 6 to 21, wherein saw wood source is selected from the group comprising hardwood and softwood.

35. A process according to claim 34, where said hardwood or softwood is provided in the form of chips, pellets or bark.