AU2005244569A1 - Process for the recovery of furfural, furfuryl alcohol and/or cellulose or cellulose-rich residues - Google Patents

Description

P:\OPERJCC\SPECIFICATIONSI2680410 specificatiom.doc.4/12I05 S-1- SPROCESS FOR THE RECOVERY OF FURFURAL, FURFURYL ALCOHOL AND/OR CELLULOSE OR CELLULOSE-RICH RESIDUES The present invention relates to a process for the recovery of low molecular weight 5 phenols, furfural and furfuryl alcohol and/or cellulose or cellulose-rich residues from a lignocellulosic biomass such as for example, hard or soft woods or other plant matter. In particular, the invention relates to a process for the pyrolysis-like degradation of lignocellulosic material to recover a high yield of low molecular weight phenols, furfural and furfuryl alcohol and/or cellulose or cellulose-rich residue.

Pyrolysis is a known process involving the thermal degradation of a biomass in the absence of oxygen. The process yields three product phases; a solid residue (char), pyroligneous liquor and low BTU gases. The relative yield of each phase depends on process parameters including reaction temperature, feedstock type and particle size, heat exchange method, equipment design and specification and product collection methods.

A number of methods are known for the pyrolysis of a biomass. These include batch type, ablative, vacuum, spinning disk and fluidised bed or fast pyrolysis. The main difference between these methods is the rate of heat transfer and the continuity of the process with respect to sample processing.

Hemicelluloses are polymers of 5 or 6 carbon sugars and constitute a major component of wood. Under pyrolytic conditions at temperatures lower than that for lignin, hemicelluloses degrade into furans such as furfural and furfuryl alcohol, as well as other lower molecular weight fragmentation products such as acetic acid and formaldehyde.

Wood consists of at least 10-15% of hemicellulose.

Lignin is a major component of wood material. It is a complex, high molecular weight polyphenyl propane polymer with repeating units consisting of the species guaiacol and syringol. The basic function of lignin in wood is to bind the wood cells together and it accounts for about 17-40% of total wood mass. It is known that the pyrolysis of lignin P:\OPERCC\SPECIFICATIONS\1268410 s1eifeautim.doc-14/ 2/05 S-2-

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Syields low molecular weight phenols, in particular guaiacol (and syringol in the case of hardwoods) and its para-alkyl substituted derivatives. Relatively recent research has demonstrated that very rapid pyrolysis of lignocellulosic material yields higher quantities of pyrolysis oil, as well as increased concentrations of phenols in the pyrolysis oil, C5 compared with traditional batch-type techniques. The rate of cracking of lignocellulose

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polymers is determined primarily by the reactor temperature and rate of heat transfer.

Ni Likewise, the preservation of primary products of the cracking process, or the oil, is O achieved through rapid quenching. However, if the reactor temperature is too great, the N, rate of secondary decomposition reactions becomes too great and the oil yield is reduced, apparently regardless of how efficiently the primary products are quenched. Thus, high yields of oil are achieved through a favourable balance between the rate of cracking of the wood polymers and the product residence times.

In practice, rapid pyrolysis is achieved via the fluidised bed system, although other systems are possible. In the fluidised bed system, a particulate heat exchange material having a density greater than that of the biomass, such as, for example aluminosilicate sand, is heated to the pyrolysis temperature. A gas is then passed through the sand bed.

The flow of gas imparts fluid like properties to the sand bed. The system is referred to as a fluidised bed reactor. Feedstock may be introduced into the fluidised bed on a separate stream of gas or it may be fed mechanically. Upon contact with the hot sand bed, the feedstock is pyrolysed virtually instantaneously. The movement of gas through the system transports the pyrolysis products away from the hot sand bed to various product collection systems.

At temperatures in excess of 800'C, the gas phase is the dominant pyrolysis product. Such a regime has been used to produce low BTU gases for energy production.

As temperature is decreased, the yield of gases decreases while the yield of oil and char increase. The char product may be used for iron ore processing and as a solid fuel.

Pyrolysis oil is the major product at temperatures between 350 and 600'C and because of this, most research on pyrolysis oil has been focused in this temperature region. Under conventional fast pyrolysis conditions, very little occurs below 350C.

P.\OPER\JCC\SPECIFICATIONS\12680410 specificatio.do.-14/I2/05 0-3- O SOils produced by the fast pyrolysis of lignocellulosic material between 350 and 600°C are thermally and chemically unstable and contain a large, disparate range of compounds that have proven to be very difficult to resolve. Attempts have been made to utilise these oils as a fuel for energy production. However, little success has been achieved.

,1 There has been considerable research conducted on the fast pyrolysis of O lignocellulosic material with the aim of producing phenols for adhesive purposes.

However, providing a satisfactory process is difficult due to thermal and chemical instability of the product, extreme complexity of the product, inability to scale up the process, expense of the process, and instability of the process with respect to hours of continuous run.

Australian Patent No. 758889, "Process for the recovery of low molecular weight phenols, furfural, furfuryl alcohol and/or cellulose or cellulose rich residues" describes a pyrolysis-like process for the recovery of several products. There are basically two types of products, the first of which includes low molecular weight compounds formed during the thermal decomposition and the second of which includes a cellulose rich solid residue. In the process, the decomposition of the hemicellulose component yields furfural and furfuryl alcohol as well as other low molecular weight products associated with xylose fragmentation. The reaction conditions employed are such that the lignin and cellulose components are only changed to a small degree. Therefore, the resultant solid residue, which is the partially degraded lignocellulose substrate, is composed predominantly of these latter components because the hemicellulose is extensively degraded.

Reprocessing of this residue under more severe conditions results in further decomposition, primarily of the lignin component, although significant depolymerisation, or 'chain-splitting' of the cellulose also occurs. The resultant residue therefore contains a high proportion of cellulose.

P:\OPER\JCC\SPECIFICATIONS\1268041o spmif-c6tin.doc-)4/lIO5 -4- SOverall, the process involves short substrate residence times, short product vapour residence times followed by rapid quenching, oxygen enriched reaction atmosphere, atmospheric pressure, temperatures within the range of 250-320'C, and high rates of heat transfer. In practice, these conditions are achieved by use of a fluidised bed reactor using air or some other oxygen enriched gas as the carrier gas. However, any hardware arrangement that permits these conditions could in principle be used suffice.

In O The process may be performed in two steps, where the hemicellulose is first C' degraded under one set of conditions and the residue reprocessed under another set of conditions resulting in lignin degradation. Alternatively, the steps may be combined and the process performed under the second, more severe, set of conditions.

It has now been found that the addition of a Lewis acid to the lignocellulosic substrate prior to the pyrolysis treatment provides a two-fold improvement. Firstly, it increases the yield of furfural and secondly it improves the residue as a substrate for the derivation of ethanol. These improvements, which are described below, occur as a consequence of the combination of the Lewis acid treatment with the pyrolysis-like process.

Thus, according to one aspect of the invention there is provided a process for the recovery of furfural and furfuryl alcohol from a lignocellulosic material, the process comprising introducing into a reactor a feedstock including particulate lignocellulosic material that has been treated with a Lewis acid, rapidly degrading the feedstock in the reactor at a temperature of from 250'C to 320 0 C; and quenching partially degraded feedstock and product vapours, the latter including furfural and/or furfuryl alcohol.

In principle this process of the present invention may be undertaken using any configuration of a reactor system that enables high rates of heat transfer into the particulate lignocellulose as well as rapid removal of decomposition products. In practice this can be achieved using a fluidised bed reactor as described herein. The fluidised bed may rely on a carrier gas to fluidise a bed of particles. Alternatively, the reactor may comprise a P:\OPERJCCSPECIFICATIONS12680410 speificatindo.I4/1I205

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Sfluidised bed arrangement in which a high speed screw-feed mechanism is used to fluidise particles of the bed and to transport materials into and out of the reactor. Another possibility uses a vortex reactor where particles are accelerated at high speed into a tapered reactor that may or may not be heated. Heat from the reactor surface and/or from friction D 5 generated from the increasing resistance met from the reactor surface as the particles are forced into an ever tightening spiral trajectory through the reactor provides the heat necessary for decomposition. The residence time of the particles is controlled by their O speed and angle of trajectory.

Volatile products can be removed from a fluidised bed reactor using a carrier gas or by use of a vacuum. In both cases, condensable volatile products can be collected in a variety of different ways, such as by using a quench column, water cooled condenser, electrostatic precipitator, ice cooled condenser, and the like.

One skilled in the art would understand how these various aspects of reactor design may be employed in the context of the present invention.

In one embodiment of this aspect of the invention there is provided a process for the recovery of furfural and furfuryl alcohol from a lignocellulosic material comprising: feeding a carrier gas into a reactor to facilitate a fluidised bed effect and to enable reaction products and residues to be carried away from the reactor via entrainment; introducing into the reactor a feedstock including particulate lignocellulosic material that has been treated with a Lewis acid; degrading the feedstock in the reactor at a temperature of from 250C to 320 0 C; and quenching partially degraded feedstock and product vapours, the latter including furfural and/or furfuryl alcohol.

There is also provided furfural and/or furfuryl alcohol when recovered by the process of the present invention.

According to a further aspect of the invention there is provided a process for the recovery of cellulose or a cellulose-rich material from a lignocellulosic material including: P:AOPER\JCC\SPECIFICATIONS\12680410 spciricatiimdoc-14/12105 -6-

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Sintroducing into a reactor a feedstock including particulate lignocellulosic material that has been treated with a Lewis acid; rapidly degrading the feedstock in the reactor at a temperature of from 250 0 C to 320 0 C; and quenching partially degraded feedstock to obtain cellulose and/or cellulose-rich material.

O In principle this process of the present invention may be undertaken using any configuration of a reactor system that enables high rates of heat transfer into the particulate lignocellulose as well as rapid removal of decomposition products. Similar reactors and reactor components as described above may be employed.

In one embodiment of this aspect of the invention there is provided a process for the recovery of cellulose or a cellulose-rich material from a lignocellulosic material comprising: feeding a carrier gas into a reactor to facilitate a fluidised bed effect and to enable reaction products and residues to be carried away from the reactor via entrainment; introducing into the reactor a feedstock including particulate lignocellulosic material that has been treated with a Lewis acid; degrading the feedstock in the reactor at a temperature of from 250'C to 320 0 C; and quenching partially degraded feedstock to obtain cellulose and/or cellulose-rich material.

There is further provided cellulose and/or cellulose-rich material recovered by the process of the present invention.

In general terms Lewis acids are defined as being species that are electron pair acceptors. In the present invention, the Lewis acid is required to catalyse dehydration reactions and in principle any known Lewis acid useful in this regard may be employed. In practice the Lewis acid is selected from those that are soluble and have a high thermal stability. Specific examples of compounds that have been found to be useful in practice of P:\OPER\JCC\SPECIFICATIONS\12680410 spewiricati.doc14/12/05 -7- Sthe present invention include zinc chloride, iron (III) chloride and cobalt (III) chloride.

The use of cobalt (III) chloride may be preferred.

As used herein the expression "treated with a Lewis acid" means that the particulate ND 5 lignocellulosic material has been contacted (or impregnated) with Lewis acid so that prior to introduction in the reactor the Lewis acid is provided in intimate contact with the In available surface area of the lignocellulosic material. The latter will invariably be porous Sso that treatment with the Lewis acid will involve deposition of the Lewis acid in pores of the material, as well as on the outer surfaces of the material.

For treatment of the lignocellulosic material the Lewis acid is usually dissolved in a suitable solvent and applied to the lignocellulosic material. This may be done by spraying or immersion of the lignocellulosic material in a solution containing the Lewis acid. After a suitable residence time to allow the Lewis acid (solution) to permeate/impregnate the lignocellulosic material, the solvent is recovered, typically by drying of the lignocellulosic material. The intention is that the Lewis acid is suitably and evenly deposited on and in the lignocellulosic material.

The concentration of the Lewis acid dissolved in the solvent for the treatment step may vary from case to case depending upon the potency of the Lewis acid, the type and nature of the lignocellulosic material and the treatment method to be used. Generally, a catalyst loading (mass of Lewis acid to (dry) mass of lignocellulosic material) of 5-15% wt/wt is employed.

The solvent that is used will obviously depend upon the Lewis acid that is to be used. By way of example, volatile organic solvents, such as methanol, may be used with the metal chloride compounds mentioned above.

It is in principle possible to introduce the lignocellulosic material and Lewis acid separately into the reactor. However, this may not be sufficiently effective since intimate contact between the Lewis acid and lignocellulosic material may not be readily achieved.

P:\OPER\JCC\SPECIFICATIONS\12680410 spemficatio.doc-4/I2105 -8- SFurthermore, fouling problems may arise if the Lewis acid is delivered into the reactor through reactor lines, and the like.

In the processes of the invention as described herein degradation of the feedstock in NO 5 the reactor may take place in the absence or presence of oxygen. Use of a Lewis acid in accordance with the present invention means that the presence of oxygen is not essential, and good yields can be obtained in the absence of oxygen. However, the presence of oxygen may actually contribute to improved yields. Therefore, in an embodiment of the present invention degradation of the feedstock takes place in the presence of oxygen, i.e. in an oxygen-containing atmosphere.

In accordance with the process of the present invention, after the lignocellulosic material has been degraded (pyrolysed), the Lewis acid may be recovered by dissolution in a suitable solvent. This solvent is typically the same solvent as used to treat the lignocellulosic material. Thus, the solid residue remaining after pyrolysis may be submerged in solvent and agitated to promote dissolution of the Lewis acid. The solvent is then removed and the Lewis acid recovered (for example, by evaporation of the solvent).

Recovery of the Lewis acid improves economy/efficiency of the process and ensures that the Lewis acid does not interfere with any subsequent processing of the residue.

Improvement offurfural yield In the initial stages of the process of the present invention, the reaction conditions employed are such that decomposition of hemicellulose predominates. When hemicellulose is pyrolysed, polymers undergo depolymerisation yielding constituent sugars and oligomeric fragments. If the sugar is a pentose, it may either dehydrate yielding furfural, or it may fragment yielding acetic acid and formaldehyde. Likewise, the oligomeric fragments may depolymerise further to their constituent sugars or may fragment yielding a wide range of potential products. High rates of heat transfer and short residence times are known to favour depolymerisation to sugars. For the conditions described in Australian Patent No. 758889 the rate limiting step in the formation of furfural P:\OPERJCC\SPECIFICATIONS\12680410 specificationdo4/121OS -9- Sis the dehydration of the liberated pentose sugar units. Consequently, a significant proportion of the hemicellulose is converted to fragmentation products and not furfural.

The incorporation of a Lewis acid into the lignocellulosic material prior to processing overcomes the rate limiting step of pentose dehydration, resulting in significantly improved furfural yields. Thus, if the substrate is pyrolysed under the same N, conditions described in Australian Patent No. 758889, the Lewis acid catalyses the dehydration of pentose resulting in improved furfural yield and minimising the extent of fragmentation. The Lewis acid is then preferably recovered so that it does not interfere in the reprocessing of the residues and also so that it can be recycled.

Improvement of cellulose-rich residue The production of ethanol from cellulose requires depolymerisation of cellulose to glucose. The liberated glucose may then be fermented to ethanol. Industrially, the depolymerisation of cellulose is achieved by an acid hydrolysis process, although enzymatic processes have also been developed. This hydrolysis step accounts for 25-30% of the ethanol production cost.

The residue obtained from the process described in Australian Patent No. 758889 is rich in cellulose that has also been extensively degraded with respect to the degree of polymerisation. That is, the residue is ideal as a raw material for ethanol production. This is because it is rich in cellulose, thereby permitting high yields of ethanol; (ii) its structure has been opened up by the removal of much of the hemicellulose and lignin, thereby facilitating rapid hydrolysis of the residual cellulose, and (iii) the cellulose chain length has been extensively reduced, thereby reducing the amount of hydrolysis actually required.

In accordance with the present invention treatment of the lignocellulosic material with a Lewis acid prior to pyrolysis accelerates the rate of cellulose depolymerisation during pyrolysis. Thus, the acid advantageously functions to further increase the extent of P:\OPER\JCC\SPECIFICATIONS\12680410 spsification.dmc.14/12/05 Scellulose depolymerisation so as to create a residue more easily convertible to ethanol than the residue obtained without the acid in accordance with Australian Patent No. 758889.

Under conventional pyrolysis conditions, the lignocellulose substrate is degraded to such an extent that the solid residue is composed of charcoal. This occurs because of the high reaction temperatures and/or because of long substrate residence times. The reaction conditions described in WO 00/31213 involve relatively low reaction temperatures and Sshort substrate reaction times. Such conditions minimise the extent of substrate decomposition such that the cellulose undergoes little more than a reduction in the degree of polymerisation. The extent of this reduction in the degree of polymerisation is markedly increased when a Lewis acid is incorporated into the substrate prior to its initial processing.

After the initial processing, which mainly decomposes the hemicellulose component, the catalyst may be recovered in the same manner in which it was applied so that it does not interfere in further processing for phenols recovery and so that it may be recycled.

Turning to the process of the invention more generally, and with reference to the disclosure of Australian Patent No. 758889, the classical definition of pyrolysis does not allow for the presence of oxygen in the reaction atmosphere because, at normal pyrolysis temperatures, combustion would occur. As already noted, the processes of the invention can be carried out in the absence of oxygen. However, it has been found that the presence of oxygen in the reaction atmosphere can promote the degradation of lignin to recover phenols as a degradation product. Further, it has been found that under the conditions of Australian Patent No. 758889, and indeed the present invention, the cellulose component remains substantially intact. In one embodiment, the degradation is carried out under an oxygen-enriched atmosphere.

When it is desired to produce an oil, conventional fast pyrolysis is generally conducted at a temperature of from 350 to 500C. Under such temperatures, the rate of hemicellulose, cellulose and lignin pyrolysis is high. As such, the resultant oil contains P:\OPERJCC\SPECIFICATIONS1268041O spcificationdo-14/1205 -11- Sdegradation products from all components, resulting in a complex, thermally and

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chemically unstable product which has practically no useful application without further processing and/or refinement. According to the present invention where temperatures of pyrolysis range from 250 to 320 0 C, the rate of volatile compound formation from cellulose pyrolysis is low whereas the rate of lignin pyrolysis is much higher, though still quite low compared with that at higher temperatures. The presence of oxygen in the process of the invention, however, promotes lignin degradation, thus yielding a phenol-rich oil.

O Therefore, due to the lower temperatures employed in the process of the present invention, compared with conventional fast pyrolysis processes, the oil recovered contains very little of the pyrolysis products of cellulose and is, therefore, much simpler compared to normal pyrolysis oils. Furthermore, the oils produced in accordance with the present invention advantageously contain no tar. In a preferred embodiment, the degradation of the feedstock is conducted at a temperature of from about 290'C to 310 0 C when it is desired to maximise low molecular weight phenol production. When it is desired to maximise furfural and furfuryl alcohol degradation is preferably conducted at a temperature of from about 250 0 C to 270 0

C.

Conventionally, the particle size of the lignocellulosic feedstock is 500 tm or more.

The particle size of feedstock used in accordance with the present invention, which is selected generally in consideration of operating parameters for a particular application is preferably less than 1mm in at least one dimension, but is generally considerably smaller than that conventionally employed. The reasons for the use of such small particles is threefold.

Firstly, the retention time for feedstock in the reactor is very short, being only slightly longer than that used in conventional fast pyrolysis processes. As such, the time available for heat transfer is comparable to that in conventional fast processes. However, due to the lower temperatures used according to the invention, the heat available for transfer is considerably less. Therefore, the extent to which pyrolysis occurs will be less if the invention is compared to conventional fast pyrolysis processes using conventional particle sizes. In order to overcome this, a much smaller particle size is used so as to P:\OPER\JCC\SPECIFICATIONS\12680410 specificatic.dAc-14/12/05 0 -12- Senable a higher rate of pyrolysis due to the lower energy requirement compared with that for larger particles.

Secondly, the mass of the particles used in the invention is much less than that ND 5 normally used. This means that their removal from a reactor environment is simpler. The velocity of the carrier gas required to entrain the partially pyrolysed particles and carry Sthem out of the reactor to a cooler environment (thus preventing secondary pyrolysis/charring) is comparatively low, thereby permitting a sufficient residence time for the particles in the fluid bed.

Thirdly, for small particles, the reaction atmosphere is more likely to be able to penetrate completely into the particle, thus homogenising the atmospheric effect. For larger particles this is less likely to occur.

In a preferred embodiment, the lignocellulosic material has a particle size of from 100 to 250im in at least one dimension. It will be recognised that optimal particle sizes may be determinable depending on the parameters used in a particular application of the invention.

Production of guaiacol (2-methoxy phenol), the dominant phenol in distillate samples recovered using the invention, has been found to be greatest when particle size is small (less than 500im) in an atmosphere of air and at a temperature of approximately 300 0

C.

Since the degradation reaction is conducted just below the activation temperature for cellulose, the solid residues mainly contain unpyrolysed cellulose. When all reactions parameters are at the optimum, the separation of volatile products of pyrolysed lignin and extractives from the unreacted residue is advantageously quite complete.

The reactor comprises a fluidised bed containing sand particles. Unlike conventional applications, however, where sand particle size in the bed is generally from P:\OPER\JCC\SPECIFICATIONS\12680410 specifieatinmdo14/12/O V-13- 250 to 1000 tm, the fluidised bed used in the process of the invention preferably contains sand of a particle size from about 100 to about 500pm.

The small particle size of the lignocellulosic feedstock permits a lower carrier gas feed rate than is conventionally used. Preferably, the feedstock is fed into the reactor in a stream of carrier gas. The flow rate of the carrier gas is less than that conventionally used (generally in the order of 6 litres/minute or more), and is expected to vary according to the Scross sectional area of the reactor. For example, the flow rate may be from about 4 to C, about 6 litres/minute for a cylindrical reactor with a diameter of 50 mm.

In order to immobilise the solid residue and separate it from the liquid product a new system has been developed. The system comprises an inner section which facilitates the deposition and collection of solid residues entrained in the carrier gas stream. The temperature in this section is preferably less than 250C. As such, the solid residue will not undergo further pyrolysis. The carrier gases than pass to the next stage of the system, which is a quenching process. The carrier gas is advantageously bubbled through a solvent causing most of the associated pyroligneous vapour to be condensed. The solvent is preferably kept at a temperature below 0°C. After the carrier gas has passed through the quenching fluid it then enters an electrostatic precipitator where any material not condensed in the quenching system is immobilised.

It has been found that the solid residue contained in the inner vessel of the quenching system is generally in good condition. That is, it contains no char. Further, the residue has been found to be significantly de-lignified and contains a high proportion of cellulose.

It should be noted that the specific embodiment described above is one which has been devised for bench top operation and may require modification or variation in scale-up to industrial application. As such, this should not be construed as limiting on the invention in any way.

P:\OPER\JCC\SPECIFICATIONS\1268O41o specificatin.do.14/12/05 -14- Further, it has been found that the process of the invention which advantageously provides a multi-stage degradation, more particularly a three stage degradation, of specific constituents of wood in turn results in products having desirous and improved characteristics compared with products obtained by prior art processes.

Those skilled in the art will appreciate that the invention described herein is N susceptible to variations and modification other than those specifically described. It is to be understood that the invention includes all such variations and modifications which fall within its spirit and scope. The invention also includes all the steps, features, compositions and compounds referred to or indicated in this specification, individually or collectively, and any and all combination of any two or more of said steps or features.

Claims (12)

1. A process for the recovery of furfural and furfuryl alcohol from a lignocellulosic material, the process comprising: introducing into a reactor a feedstock including particulate lignocellulosic material that has been treated with a Lewis acid, I rapidly degrading the feedstock in the reactor at a temperature of from O 250 0 C to 320 0 C; and quenching partially degraded feedstock and product vapours, the latter including furfural and/or furfuryl alcohol.

2. A process for the recovery of furfural and furfuryl alcohol from a lignocellulosic material including: feeding a carrier gas into a reactor to facilitate a fluidised bed effect and to enable reaction products and residues to be carried away from the reactor via entrainment; introducing into the reactor a feedstock including particulate lignocellulosic material that has been treated with a Lewis acid; degrading the feedstock in the reactor at a temperature of from 250 0 C to 320 0 C;and quenching partially degraded feedstock and product vapours, the latter including furfural and/or furfuryl alcohol.

3. A process for the recovery of cellulose or a cellulose-rich material from a lignocellulosic material including: introducing into a reactor a feedstock including particulate lignocellulosic material that has been treated with a Lewis acid; rapidly degrading the feedstock in the reactor at a temperature of from 250 0 C to 320 0 C; and quenching partially degraded feedstock to obtain cellulose and/or cellulose- rich material. P:\OPERVCC\SPECIFICATIONS\12680410 specifijation.do-14/12IO5 -16- O

4. A process for the recovery of cellulose or a cellulose-rich material from a lignocellulosic material including: feeding a carrier gas into a reactor to facilitate a fluidised bed effect and to enable reaction products and residues to be carried away from the reactor via entrainment; Sintroducing acid into the reactor a feedstock including particulate lignocellulosic material that has been treated with a Lewis; degrading the feedstock in the reactor at a temperature of from 250'C to 320 0 C; and quenching partially degraded feedstock to obtain cellulose and/or cellulose- rich material. A process according to any one of claims 1 to 4, wherein the Lewis acid is recovered from the degraded feedstock and optionally recycled for reuse.

6. A process according to any one of claims 1 to 4, wherein after treatment of the lignocellulosic material with the Lewis acid, the Lewis acid is present in the lignocellulosic material in an amount of from 5 to 15% by weight based on the (dry) weight of the lignocellulosic matreial.

7. A process according to any one of claims 1 to 4, wherein the Lewis acid is selected from zinc chloride, iron (III) chloride and cobalt chloride.

8. A process according to any one of claims 1 to 4, wherein the degradation is carried out under an oxygen-enriched atmosphere or an air atmosphere.

9. A process according to claim 1 or claim 2, wherein the degradation of the feedstock is conducted at a temperature of from about 250 0 C to 270 0 C. P:\OPER\JCC\SPECIFICATIONS\12680410 specificatimdoc-14/I OS -17- O A process according to claim 1 or claim 2, wherein the degradation of the feedstock is conducted at a temperature of from about 290 0 C to 310 0 C.

11. A process according to any one of claims 1 to 4, wherein the lignocellulosic 5 material has a particle size of less than 1 mm in at least one dimension. t, 12. A process according to any one of claims 1 to 4, wherein the lignocellulosic Smaterial has a particle size of from 100 to 250 jtm in at least one dimension.

13. A process according to claim 2 or claim 4, wherein the reactor comprises a fluidised bed containing sand particles.

14. A process according to claim 13, wherein the fluidised bed contains sand particles having a particle size of from about 100 to about 500m. A process according to any one of claims 1 to 4 substantially as hereinbefore described.

16. Furfural, furfuryl alcohol, and/or cellulose or cellulose-rich material recovered by a process according to any one of the preceding claims. DATED: 14 December, 2005 by DAVIES COLLISON CAVE Patent Attorneys for the Applicant(s): THE UNIVERSITY OF MELBOURNE