STEAM PYROLYSIS OF CARBONACEOUS SOLIDS

FIELD OF THE INVENTION

The present invention generally relates to the exploitation of carbonaceous, solid waste materials, and biomass, especially lignocellulosic materials for bio-oil production, and in particular to an advanced one step process that can produce upgraded bio-oil directly from solid waste materials or biomass by hydrodeoxygenation (HDO) using high-temperature steam, as well as an arrangement for carrying out the inventive process.

DESCRIPTION OF THE PRIOR ART

Biomass is a renewable energy source with increasing potential in the worldwide energy market, and its net carbon dioxide emissions are essentially neutral, thus not contributing to the greenhouse effect. Moreover, its very low nitrogen (N) and sulfur (S) contents add to the environmental friendly character of such a material.

Municipal solid wastes also to a large extent comprises biomass and offer increased sustained potential for biofuel production, with cleaner environment. The plastics from municipal solid wastes also offer clean biofuel production with characteristics similar to that of biodiesel liquids.

The most important advantage of biomass, apart from its neutral CO2 net characteristic, is that it can be converted to liquid, solid, or gaseous fuels, unlike other renewable sources of energy (e.g. wind, and solar energy), which only give heat and power.

Similarly, the municipal solid wastes that are also biomass can be converted to liquid fuels for use in propulsion and power systems. The dumping of plastics in landfill causes environmental issues, since the plastics are not biodegradable. The energy content in plastics is much higher than in biomass materials, so that its fuel reforming would offer benefits of negative cost fuels from such wastes, improved environment, and a permanent solution to the plastic wastes.

Therefore, biomass, solid wastes and plastics can be considered as a renewable re- source which could be directly transformed into liquid fuel and value added products and chemicals.

The research in the area of transforming biomass has mostly focused on two aspects of thermochemical and bio-chemical processes. Biomass pyrolysis has at- tracted the highest interest amongst the thermochemical conversion technologies as it offers renewable liquid, gaseous and solid products converted by optimized technology conditions.

There are basically two methods being used to produce oil from biomass: high pres- sure liquefaction (typically hydro thermal for biomass), and atmospheric pressure fast pyrolysis. Available biomass pyrolysis technology for bioliquid production is to convert organics to solid, liquid and gas by heating in the absence of oxygen.

Fast pyrolysis of biomass is one way to generate liquid from biomass. This is the most intensively investigated pyrolysis process at present. The key issues in order to obtain as much liquid as possible are rapid heating and rapid quenching. External heat is generally provided by sand in fluidized-bed reactors, or by a hot wall, such as in ablative (vortex and rotating blade) reactors. The main heat transfer modes are conduction and convection. Fast pyrolysis has been developed relatively recently. Intensive studies were carried out in 70s. Presently, many laboratories around the world are trying to commercialize "fast wood pyrolysis" to liquid. Demonstration plants include 400 kg/h at Dynamotive with fluidized bed reactor, 1 ,000 kg/h CFB at Red Arrow, and 20 kg/h at VTT. 120 kg/h of rotating cone reactor at BTG, (Netherlands), 3,500 kg/h at Pyrovac with a vacuum reactor, 350 kg/h at For- turn, Finland with an ablative reactor, and 200 kg/h at Mississippi State University, USA with an auger reactor. However, bio-oil, directly derived from these traditional processes, is usually of high viscosity and exhibits a high content of oxygenated components, a low stability and a low heat value, and thus further processing and upgrading of the bio-oil is required. The oxygenated compounds present in raw bio-oil impart a number of un- wanted characteristics to the bio-oil, such as thermal instability (reflected in increasing viscosity upon storage of the bio-oil), corrosiveness and low heating value. This instability is associated with the presence of reactive chemical species, mainly aldehydes, ketones, carboxylic acids, alkenes and guaiacol-type molecules. During prolonged storage, condensation reactions involving the above mentioned functional groups result in formation of heavier compounds due to polymerization reactions.

From all the above it can be understood that upgrading biomass-derived oils to hydrocarbon fuels requires oxygen removal and water content and molecular weight reduction. In order to improve quality of the thus obtained bio-oil usually processes such as cracking, hydrogenation, and steam reforming are involved. An upgrading process of this kind of oil is needed. The concept of achieving a conversion of ligno- cellulosic biomass into liquid biofuels that are physically and chemically compatible with petroleum-based hydrocarbon fuels can be expressed by the formula:

Biomass -» Volatile (C _x H _y O _z )+ Char (C) C _x H O > -CH ₂ -

Upgrading biomass-derived oils to hydrocarbon fuels requires oxygen removal and molecular weight reduction. This requires that hydrogen is added in the process to increase the H/ C ratio of the product and to remove excess oxygen as water.

To date, two main deoxygenation methods have been investigated. The first comprises bio-oil cracking at atmospheric pressure, resulting in simultaneous dehydra- tiondecarboxylation.

Before cracking, however, the bio-oil must be vaporized. Such vaporization process is energy intensive, and causes undesired coke formation reactions and condensation reactions. If catalytic cracking is being employed severe coking and therefore deactivation of the catalysts will put a limitation to their application. The second method for bio-oil upgrading utilizes typical hydrotreating conditions, i.e., high hydrogen pressures for the hydrogenation of unsaturated groups (with elimination of oxygen as water) and hydrogenation-hydrocracking of large mole- cules. Although hydrotreating is extremely effective, techno-economic analyses reveal its economics to be unfavorable for the production of the fuel-type products it affords. Hydrogen is typically derived from steam methane reforming, which is dependent on methane, and is therefore not normally considered a renewable source. Alternative methods of hydrogen production include the use of water electrolysis. The prior art methods of producing hydrogen are relatively costly.

The most suitable and effective method for upgrading bio-oil is hydrodeoxygenation (HDO). During HDO, oxygen in the feed is converted to ¾0 which is environmentally benign.

The main problems with the upgrading methods described above is the coke deposition, and, as a result, catalyst deactivation, even though several catalysts have been tested, as well as the hydrogen availability and complexity of high pressure processes.

Moreover, the above prior art bio-oil upgrading processes are being carried out offline from the pyrolysis, using pyrolysis derived bio-oil as raw material. Accordingly, it would be desirable to provide a process enabling on-line bio-oil upgrading.

A method solving the above problems has recently been disclosed by Kantarelis, E.; Liu, J.; Yang, W.; and Blasiak, W., Sustainable Valorization of Bamboo via High- Temperature Steam Pyrolysis for Energy Production and Added Value Materials, Energy Fuels 2010 (DOI: 10. 1021 /efl00875g published on 1 November 2010, accessible from http: / /pubs. acs.org) , the contents of which is incorporated herein in its entirety by reference.

The inventive method is a fast pyrolysis process for the production of bio-oil from a carbonaceous, solid raw material selected from waste materials and biomass materials, or a mixture thereof, and especially lignocellulosic raw materials. The method uses high-temperature steam to pyrolyse the raw material. By virtue of the presence of high-temperature steam during the pyrolysis, deoxygenation of oxygenated spe- cies in the pyrolysis gas will also be accomplished at the same time.

It has recently been found by same inventors, that the deoxygenation can be further enhanced by means of providing additional hydrogen radicals (H*) to the process, which radicals can be readily generated, using electrical means, from the high- temperature steam.

According to the invention, upgraded bio-oil can be produced in a one-step process. SUMMARY OF THE INVENTION

The present inventors have found that, when high-temperature steam is used for pyrolysis of a lignocellulosic raw material, the degree of oxygenation in the resulting pyrolysis gases will be reduced. As alluded to in the article by Kantarelis et al.

above, hydrogen may be transferred to the oxygenated or unsaturated molecules, and this generally enhances the quality of the resulting bio-oil.

While the present invention as described herein has been focused on using lignocellulosic raw materials, the present inventors also believe that the inventive method could be used for converting carbonaceous solid waste materials and biomass materials in general, such as municipal solid waste, waste plastics, waste tyres, and biomass, such as e.g. lignocellulosic biomass. The oxygen content of waste plastics and waste tyres is likely to be comparatively low in general, and therefore, when such materials are being used as the sole raw material for the process, the deoxy- genation capacity of the inventive process will not be taken full advantage of. Accordingly, it is preferred that the raw material, or mixture of raw materials, for the process contains a substantial amount of oxygen containing compounds. Preferably, municipal solid waste and / or biomass is used as the raw material in the inventive process, and more preferably biomass, especially lignocellulosic biomass.

Accordingly, in a first aspect, and with reference to Figure 1 , the invention relates to a method of producing bio-oil 120 from a carbonaceous, solid raw material 40 selected from waste materials and biomass, and mixtures thereof, which method in its most generic embodiment comprises the steps of: (a) providing a carbonaceous, solid raw material 40; (b) subjecting the carbonaceous, solid raw material to conditions effective for accomplishing fast pyrolysis of said carbonaceous, solid raw ma- terial; (c) subjecting the oxygenates formed in step (b) to conditions effective for accomplishing deoxygenation of said oxygenates; and (d) cooling the components 60 formed in step (c), in order to obtain liquid bio-oil 120, wherein steps (b) and (c) are accomplished by means of subjecting the carbonaceous, solid raw material to high- temperature steam 28 at a temperature within the interval of 400-700°C.

By means of the method, the resulting bio-oil obtained upon quenching will be upgraded in respect of both hydrogen content, and also in respect oxygen content, i.e. the oxygen content will be low.

In the inventive method, steps (b) and (c), i.e. the pyrolysis and the deoxygenation, respectively, can be carried out in the same reactor 30.

Also, steps (b) and (c) can be combined into one step, wherein the raw material is subjected to preheated high-temperature steam.

As opposed to the prior art, no intervening condensation or recovery step between the pyrolysis step and the deoxygenation step is required, and steps (b) and (c) can be combined into one step. Thus, upgraded, low oxygen content, hydrodeoxygen- ated bio-oil can be obtained in merely one step, in addition to the quenching step, that is.

Accordingly, any energy intensive vaporization of raw bio-oil, such as in the prior art off-line cracking processes used for upgrading the bio-oil, is avoided by means of the inventive in-line upgrading process.

Also, undesired coke formation reactions and condensation reactions associated with the prior art vaporization process are avoided by means of the invention. In the inventive process, no catalyst is required, and therefore any problem of deactivation of the catalyst due to e.g. coking is avoided.

Additionally, the use of high-temperature steam in the pyrolysis has been found to reduce the yield of char. The char produced from the inventive process using high- temperature steam has been found to exhibit a higher surface area and higher carbon content, than char obtained from conventional pyrolysis. The char produced by the inventive process can therefore be used as e.g. an activated carbon precursor.

Also, by using steam, any co-produced synthesis gas during the process will not be diluted, as opposed to when e.g. N2, or another inert gaseous component is being used. According to the claimed process, only steam is required to be added. The hydrogen enriched gas that is produced can thus be utilized for heat generation for providing the necessary high-temperature steam of the inventive process, as well as raw material for chemical synthesis. The bio-oil of the present invention generally comprises products containing low oxygen to carbon ratio (0:C) which is essential for a good quality bio-oil. This will enhance the production, as well as the use of bio-oil as transport fuel substitute or/ and chemicals. The present inventors have found the resulting bio-oil obtained by means of the method to have a reduced content of soot, a reduced viscosity, enhanced storage- life, and a lighter colour, than conventionally obtained bio-oil. Accordingly, as opposed to the prior art pyrolysis oil, which is usually black and opaque, the bio-oil of the invention is typically yellow to brown in colour, and essentially transparent.

Recently, the inventors found that step (c) of the above generic embodiment of the method can be substantially enhanced by providing additional hydrogen radicals (H*) to the process, which radicals can be readily generated, using electrical means 50, from the high-temperature steam present in the process, that is in steps (b) and (c).

The inventors have found that, at the relevant temperature, water molecules (H2O) of the preheated high-temperature steam will to some extent dissociate into radicals (H* and OH*). This is presently believed to the main reason for the observed hydro- genation and oxygenation in the above article by Kantarelis et al. Especially the hydrogen radicals (H*) are believed to effectively contribute to the deoxygenation of oxygenated species in the pyrolysis gas by reacting with said oxygenated species. The type of deoxygenation of the invention can therefore be designated as hydrode- oxygenation (HDO). According to the invention, the high-temperature steam consequently serves the dual purposes of both constituting a heat carrying agent, which supplies the major part of the necessary heat for effecting pyrolysis, and also constituting a source of hydrogen radicals, thus also supplying a reactive agent (H*) that will serve to deoxy- genate oxygen containing species in the pyrolysis gas, whereby the bio-oil, obtained upon quenching, will be upgraded in this respect and exhibit a low oxygen content.

The provision of additional hydrogen radicals in the process will therefore further improve the quality of the resulting bio-oil, by virtue of additional deoxygenation and hydrogenation.

Accordingly, in a preferred embodiment of the method, additional hydrogen radicals (H*) are being generated and supplied to the method. The additional hydrogen radicals are being formed from the high-temperature steam in using electrical means. Oxygenates formed in pyrolysis step (b) are then brought into contact with the hydrogen radicals thus formed. Thereby, deoxygenation of oxygenates contained in the pyrolysis gas will be enhanced, and the quality of the resulting bio-oil further improved. For large scale operations, the use of a hydrogen radical generator will also serve to offer effective means of controlling the process, in terms of desired extent of hydrogenation and deoxygenation.

In another aspect the present invention relates to a corresponding arrangement for carrying out the above preferred inventive method comprising: a pyrolysis reactor 30 with the capability of withstanding temperatures in the range of 400-700°C, which reactor exhibits an inlet for a carbonaceous, solid raw material 40, and an inlet for high-temperature steam 28 of a temperature within the interval of 400- 700°C; and quenching means 100 for cooling the pyrolysis gas 60 obtained in the pyrolysis reactor 30, wherein the reactor further comprises electrical means 50 for producing hydrogen radicals (H*) from the high-temperature steam within the reactor.

In a preferred embodiment, the arrangement also comprises separation means 70, such as e.g. a cyclone, for removing char and solid residues from the pyrolysis gas before quenching.

In yet a preferred embodiment the quenching means 100 is also provided with electrical means 50 for producing hydrogen radicals (H*) from the high-temperature steam within the quenching means.

In a preferred embodiment, an arrangement for carrying out the above generic inventive method comprises: a pyrolysis reactor 30 with the capability of withstanding temperatures in the range of 400-700°C, which reactor exhibits an inlet for a car- bonaceous, solid raw material 40, and an inlet for high-temperature steam 28 of a temperature within the interval of 400-700°C; and quenching means 100 for cooling the pyrolysis gas obtained in the pyrolysis reactor 30, wherein the arrangement further comprises separation means 70 for removing char and solid residues 80 from the pyrolysis gas 60 before quenching, so as to obtain clean pyrolysis gas 90, which then can be quenched in cooler 100 so as to form bio-oil 120.

Another objective is the online reforming of complex long chain hydrocarbons and cyclic hydrocarbons, formed from the carbonaceous, solid raw material fed into the process upon pyrolysis thereof, to enhance the hydrogenation of the produced bio- oil.

Other objects and advantages of the present invention will become obvious to the reader skilled in the art and it is intended that these objects and advantages are within the scope of the present invention.

According to the embodiments of the present invention, biomass undergoes pyrolysis producing liquid oil, value added products and gaseous fuel products. The term liquid oil' as used herein means a liquid which is obtained upon quenching of the pyrolysis gases, and which is in a liquid state at room temperature. The terms liq- uid oil, bio-oil and pyrolysis liquid have been used interchangeably herein.

The inventive method is carried out in continuous operation. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a general system flow diagram, wherein reference numeral 28 denotes a high-temperature steam inlet, 30 denotes a pyrolysis reactor, 40 carbona- ceous feeding, 50 hydrogen radical generators, 60 pyrolysis gas generated from pyrolysis reactor, 70 a cyclone separator, 80 char and solid residues, 90 clean pyrolysis gas, 100 a cooler, 1 10 syngas obtained from the process, and 120 denotes bio- oil obtained from the inventive process. Figure 2 shows a pilot batch plant, which was used for carrying out the inventive method in batch mode operation on a pilot scale, wherein 1 -4 denotes gas nozzles, 5 air nozzle, 6 methane nozzle, 7 gas burner, 8 combustion chamber, 9 ceramic honeycomb, 10 cooling chamber, 1 1 lid, 12 online gravimetric measurement, 13 cooling nitrogen nozzle, 14 perforated basket with sample, 15 flue gases, 16 sam- pling line, 17 gas washing bottle for liquid collection, 18 reaction chamber, 19 window, 20 thermocouple for steam temperature measurement, 21 thermocouple for sample temperature measurement, 22 cooling bath of -15°C to - 10°C, 23-26 cooling water, and 27 denotes a gas chromatograph. The pilot batch plant is not an embodiment of the arrangement of the invention.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS THEREOF

Introduction of high-temperature steam in biomass pyrolysis process results in a low oxygen content upgraded bio-oil with an O/C ratio less than 0.2. The introduction of high-temperature steam allows the reforming and cracking of heavy bio-oil molecules to lower molecular weight substances while the hydrogen radicals that are present due to steam dissociation reactions are taking part in the hydrodeoxy- genation (HDO) of the primary oxygenated species resulting from the pyrolysis. The inventive system includes a biomass pyrolysis reactor 30 working in the temperature range of 400°C to 700°C, into which reactor high-temperature preheated steam of a temperature within the range of 400°C to 700°C is injected. The stream is not only acting as a heating agent supplying the major part of the heat necessary for the pyrolysis, but also acting as a hydrogen donor, providing reactive hydrogen which will react with oxygenates in the pyrolysis gas, and thereby reduce the oxygen: carbon in order to get rid of oxygen. The preferred working temperature range of the pyrolysis reactor, and also of the high-temperature steam being fed into the reactor, is within the interval of about 440°C to 600°C.

The heat required for the pyrolysis is mainly provided by the high-temperature steam entering the reactor. However, additionally heating will typically be required in order to maintain the temperature within the pyrolysis reactor within the range of 400-700°C. The additional heat can be provided by electrical heating of the reac- tor, and/ or by means of hot flue gases being passed into the pyrolysis reactor from combustion outside the reactor, such as e.g. from upstream generation of high- temperature steam. Such flue gases could enter the pyrolysis reactor together with the high-temperature steam, or via a separate inlet. Accordingly, the pyrolysis reactor may be provided with means for electrical heating thereof and / or an inlet for hot flue gases.

In a preferred embodiment the pyrolysis reactor uses a fixed or fluidized bed, preferably a fluidized bed, to which the carbonaceous raw material is being fed. The pyrolysis reactor is preferably operating at essentially atmospheric pressure, since otherwise the bio-oil yield will decrease. Also, for the same reason, the high- temperature steam is fed into the pyrolysis reactor preferably at about atmospheric pressure. Preferably, the pyrolysis reactor is provided with electrical means for generating hydrogen radicals from the high-temperature steam in the pyrolysis reactor. Hydrogen radicals can e.g. be generated by means of electrical discharge, such as electrodes, or plasma. The electrical discharge is preferably operating continuously during the pyrolysis. In the case of a fixed or fluidized bed, the electrical means (discharge or plasma) is preferably located in the freeboard of the bed.

In the inventive process, the bio-oil produced during the pyrolysis process is simultaneously cracked and reformed in the presence of steam to produce ¾. Produced hydrogen can take part in hydrogenation reactions; in addition hydrogen radicals from the highly superheated steam, and/or from the electric spark, or plasma, can also take part in the HDO of the of the oxygenated species contained in the pyroly- sis gas, so as to produce an upgraded bio-oil. The hydrogen radicals are very reactive during thermal cracking.

Hydrogen radicals are hydrogen donors enhancing the online upgrading of the produced bio-oil. The above mentioned can be schematically depicted by the following scheme:

+ H *

C _x H O _z > -CH ₂ - y -H ₂ 0

The above mentioned features result in a low oxygen content bio-oil, which is essential for the stability and overall quality of the resulting bio-oil as a fuel.

The co-produced gas is a hydrogen rich gas and therefore a valuable gas product.

The solid residue produced from the process exhibits enhanced surface characteristics that can enhance the exploitation of the material.

The pyrolysis vapors leaving the reactor are being passed through a tube and are rapidly quenched. With reference to the pilot plant illustrated in Figure 2, this can be accomplished using gas washing bottles at temperatures of - 10°C down to - 15°C, and a cooling bath. In large scale plants, the cooling temperature will typically be atmospheric or ambient. Condensable molecules are then obtained as a liquid, i.e. as bio-oil.

Having read the instant disclosure, optimum dimensional relationships for the parts of the invention, including variations in size, materials, shape, form, function and manner of operation, assembly and use, will be readily apparent and obvious to one skilled in the art.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as defined in the appended claims.

In accordance with the present invention, and with reference to Fig. 1 , there is provided a process for converting carbonaceous materials to liquid. In a preferred embodiment the process comprises the following steps. Feeding preheated high- temperature steam 28 of a temperature within the range of 400°C to 700°C, which can be generated by a regenerative system, an electrical heater, a boiler, or from combustion of hydrogen and oxygen. Feeding the carbonaceous, solid material 40 into pyrolysis reactor 30. The reactor 30 is operating in the temperature of 400°C to 700°C. The temperature of reactor 30 is maintained by an electric heater (not shown), or by hot flue gases from combustion of e.g. biomass, or syngas 110 ob- tained from the process, or solid residue 80 (predominantly char) generated from pyrolysis reactor 30. A hydrogen radical generator 50 is installed in the reactor 30. This generator produces hydrogen radicals (H ^* ), which are used as a hydrogen donor for the deoxygenation process of the pyrolysis gas. The stream of pyrolysis gas 60 generated from the pyrolysis reactor 30 passes through a cyclone separator 70. Here, solid residues 80 can be separated from the pyrolysis gas stream 60. A clean pyrolysis gas stream 90 exiting cyclone 70 flows into a cooler 100. Here, most of the gas is cooled to produce a pyrolysis liquid (i.e. bio-oil) 120. The pyrolysis liquid can then can be collected from the process. A hydrogen radical generator 50 is also installed in the cooler 100 in order to provide hydrogen radicals also at this loca- tion, enabling additional deoxygenation reaction of the gaseous oxygenates and hy- drogenation reaction of gaseous unsaturated compounds before being converted into a liquid state.

The following Example is provided for a better understanding of the features, as- pects, and advantages of the present invention.

EXAMPLE

The principal steps of the inventive process were carried out in batch-wise operation mode on a pilot scale apparatus as shown in Fig. 2. The pilot scale apparatus is based on a universal batch reactor, which reactor has been developed for a different purpose and has been described in more detail by Anna Ponzio, Sylvester Kalizs, Juliette Promelle, Wlodzimierz Blasiak, Susumo Mochida, Combustion of wood pellets in a high temperature and oxygen diluted environment, Proceedings from 6 ^th Hi- TACG conference 2005 , Essen 2005. The pilot scale plant shown in Figure 2 is not an arrangement according to the invention.

The experimental pilot scale rig shown in Figure 2 consists of a horizontal combustion chamber with an inner diameter about 0. 1 m. High-temperature steam was obtained as follows. Methane and air were fed via nozzles 5 and 6 to the gas burner 7. As the fuel burns in the combustion chamber 8 the hot flue gases will heat the ceramic honeycomb 9 and flow through the second part of the reactor 18 and towards the reactor's outlet 15. The rig is run in heating mode until the desired temperature of the honeycomb is reached. Once the proper temperature is reached, the methane feed is shut off and the experimental stage started. The proper feed gas (in this case N2) is set by adjusting the flow of steam and the resulting heating agent is fed through feed gas nozzles 1-4 and is heated by the hot honeycomb 9. The heated agent temperature is measured by a thermocouple 20. A portion of a feedstock is attached to a piston as a thin bed in a basket 14 fabricated by metal net for this purpose. The lid 11 with the piston and the feedstock sample is attached to the rig, with the feedstock sample in a small cooling chamber 10 where it is cooled by nitrogen 13. The experiment starts when the sample on the piston is pushed down into the reactor chamber 18 from above. Once the sample is in the chamber, the sample is visible through glass window 19. The temperature of the sample is measured by a thermocouple 21. Thereafter, the basket is lifted from the chamber to the cooling chamber 10 in order to quench the reactions through cooling with nitrogen. The pyrolysis vapors leaving the reactor are passed a sampling line 16 and they are rapidly quenched by gas washing bottles 17 to temperatures of - 10°C down to - 15°C, using a cooling bath 22. Condensable molecules are obtained as a liquid. The gases are driven to GC analyzer 27.

Bamboo has been tested in above facility. The particle size of the bamboo was about 200-500 μπι. The elemental analysis was performed using a Vario Micro Elemental Analysis instrument. The alkali content and other metals that can be found in the ash of the material were analyzed using a PE5300DV inductively coupled plasma spectrometer. Table 1 Analysis of the raw material

Moisture [%wt] 1.87

Cellulose [%wt] 39.61

Hemicellulose [%wt] 17.53

Lignin [%wt] 22.61

Extraction mat- ter[%wt] 18.38

Ultimate Analysis

C [% wt] 47.98

H [% wt] 6.59

O [% wt] 42.875

N [% wt] 1.93

Al [% wt] 0.004

Ca [% wt] 0.044

Fe [% wt] 0.05

K [% wt] 0.417

Mg [% wt] 0.044

Mn [% wt] 0.01

Na [% wt] 0.042

P [% wt] 0.012

Zn [% wt] 0.002

The quality of the inventive bio-oil generated from bamboo via fast pyrolysis in presence of steam was assessed. The results show that the ratio H/C is 1.51 , and the ratio of O/C is 0. 16. Both values demonstrate a good quality of the resulting bio-oil.

The water content in the resulting liquids were around 30% and the liquids obtained were fully miscible in water.

The bio-oils obtained were transparent, brown liquids. Elemental composition of bio-oil obtained from steam pyrolysis at 797 K (523.85°C)

Component Content [%wt]

High-Temperature

Steam Pyrolysis at

797 K (523.85°C) (this

study)

C 74.44

H 9.55

O 16.01

During the pyrolysis process of bamboo, the yields of different productions at different temperature are given below.

Temp. K Char Bio-oil Gases

(°C) (solid) wt% wt% wt%

797 25 55 20

(523.85)

865 21 43 36

(591.85)