WO2018041975A1

WO2018041975A1 - Hydrolysis and hydrolysis reactor

Info

Publication number: WO2018041975A1
Application number: PCT/EP2017/071914
Authority: WO
Inventors: Benjamin Mckay; Gerardus Johannes Maria Gruter; Martijn KERSBULCK; Leonard Paul BALKESTEIN
Original assignee: Avantium Knowledge Centre B.V.
Priority date: 2016-08-31
Filing date: 2017-08-31
Publication date: 2018-03-08

Abstract

A hydrolysis of particulate lignocellulosic material with hydrochloric acid, characterized in that the hydrolysis is carried out in a hydrolysis reactor, which hydrolysis reactor comprises - a cylindrical body with a wall structure of filament-wound composite, which reactor is provided with at least one inlet opening at one end of the cylindrical body and with at least one outlet opening at the opposite end of the cylindrical body; and - a plastic lining inside the cylindrical body. And a hydrolysis reactor for the hydrolysis of particulate lignocellulosic material with hydrochloric acid, comprises a cylindrical body with a wall structure of filament-wound composite, which reactor is provided with at least one inlet opening at one end of the cylindrical body and with at least one outlet opening at the opposite end of the cylindrical body; and a plastic lining inside the cylindrical body.

Description

Hydrolysis and Hydrolysis reactor

FIELD OF THE INVENTION

The present invention relates to a hydrolysis reactor, in particular to a hydrolysis reactor that is suitable for the hydrolysis of particulate lignocellulosic material with

hydrochloric acid.

BACKGROUND TO THE INVENTION

The hydrolysis of wood and other lignocellulosic material has been known for many years. Lignocellulosic material typically comprises cellulose and hemicellulose from which mono- and oligosaccharides can be obtained in addition to lignin. Lignin comprises cross- linked phenol polymers and is believed to contain coumaryl alcohol, coniferyl alcohol and sinapyl alcohol as building blocks. There appears to be a number of approaches to liberate mono- and oligosaccharides from lignocellulosic material. One of the approaches is enzymatic hydrolysis. A second approach is the hydrolysis with hot compressed or even supercritical water. Such hydrolysis requires the application of high temperatures, e.g. 200 to 400 ⁵C and high pressures, e.g. 50 to 250 bar, at short contact times. Another approach is the use of dilute acid. Examples of such a method are the Scholler and Madison processes which are described in e.g. US 5879463 and DE 640775. While sulfuric acid is used in these actual processes, the use of dilute hydrochloric acid and phosphoric acid is also known in the art.

A further hydrolysis method uses concentrated acids. These methods include the Bergius Rheinau process, as described in e.g. DE 362230 and US 4199371 . In the Bergius Rheinau process wood is shredded to chips which are treated with a concentrated hydrochloric acid composition. During the treatment for instance about two-thirds of the wood is dissolved by the acid in the form of mono- and oligosaccharides, and the rest, e.g. about one-third remains as lignin. The dissolved fraction comprises mono- and oligosaccharides, together with water and hydrochloric acid. This fraction is generally referred to as the hydrolysate. The lignin fraction is obtained as a solid fraction that comprises lignin, residual water and hydrochloric acid.

The Bergius Rheinau process is generally carried out in a number of reactors in which the lignocellulosic material is sequentially digested. One reactor may be used for a so-called pre-hydrolysis, wherein the hemicellulose that is present in the wood or other lignocellulosic material is digested to yield a mixture comprising xylose, arabinose, mannose and glucose. In further reactors the material after the pre-hydrolysis is further digested, in a so-called main hydrolysis, with concentrated hydrochloric acid to yield a glucose-containing solution and lignin. Such a two-stage hydrolysis has been described in US 2945777. This patent document describes that is was already known to conduct a pre-hydrolysis of wood using a dilute acid, e.g. a hydrochloric acid having a HCI concentration of 0.5 to 1 .5 %wt at elevated temperature, e.g. 120 to 140 °C. The thus treated pre-hydrolyzed wood is then treated with concentrated hydrochloric acid. In the process according to US 2945777 softwood sawdust is subjected to a pre-hydrolysis at about 15 to 30 °C with hydrochloric acid giving a HCI concentration of 34 to 37 %wt, and the pre-hydrolyzed sawdust is subsequently hydrolyzed in a main hydrolysis with hydrochloric acid having a HCI concentration above 40%wt.

The reactors that have commonly been used, have been made of carbon steel. Since the concentrated hydrochloric acid composition that is used in the hydrolysis has a severely corrosive nature, the reactors are optionally provided with a lining of bitumen or other hydrocarbonaceous material. The lining should protect the carbon steel walls of the reactor. During operation and especially when the reactors is emptied and filled, the lining may be damaged, thereby enabling the concentrated hydrochloric acid to have its corrosive effect on the steel walls of the reactors. It has therefore been proposed to use different material for the reactors, which material is better acid-resistant.

In EP 1878480 a reactor is proposed to overcome the drawback of having to replace damaged linings in the prior art reactors. The reactor according to EP 1878480 is a tubular reactor made of a plastic and which is surrounded by a fiber-reinforced reactor shield that comprises a fabric of a range of polymers which are embedded in a matrix of concrete, PVC, polyethylene, polypropylene, polybutylene, polytetrafluoroethylene, copolymers or mixtures thereof, lignin or a lignin-formaldehyde polymer. This reactor may be satisfactory as to mechanical strength, but it is rather difficult to manufacture as a reactor has to be

constructed from plastic and then around this reactor a fabric has to be embedded in a liquid layer of polymer, which is subsequently hardened. This process is typically manual and time- consuming.

The inventors of EP 1878480 seem to acknowledge that the application of a fiber- reinforced reactor shield is difficult to construct as they subsequently propose in WO

2015/136044 a hydrolysis reactor which consists of segments that may be made from a range of polymers, which segments further comprise flanges to put them together. Allegedly, the construction provides an improved strength so that one can refrain from applying the above-described additional fiber-reinforced reactor shield. However, as indicated in

WO 2015/136044, there are limitations to the size of the reactor and thus also to the reactor segments in respect of the mechanical strength of the reactor and segments. The reactor segments are typically fabricated using pipe extrusion technology. This technology puts limits to the diameter of the pipe that may be extruded. For instance, according to US 5028376 pipes can be extruded with a diameter up to 46 inches, i.e. less than 1 .20 m. When large scale hydrolysis reactors are required, this diameter is too small. US 4199371 discloses a tubular horizontal rotary reactor that may be manufactured from a light inexpensive material such as polyolefins, PVC, aromatic polyesters and reinforced epoxies. However, such a reactor may not be sufficiently strong to hold a massive load of lignocellulosic material.

The use of the above mentioned reactors according to the prior art disadvantageously reduces the robustness and/or economics of the Bergius Rheinau process, i.e. because of more frequent maintenance being needed and/or expensive manufacturing of the equipment being needed and/or difficulties in scaling up of the volume to be processed. In addition, the use of prior art reactors that are prone to corrosion of the lining increases the risks from a health, safety and environment (HSE) perspective, especially for a hydrolysis method using concentrated hydrochloric acid.

The present inventors therefore set out to provide a process that is more economic, more robust and/or has an improved HSE profile. In addition, the inventors set out to provide a reactor that is sufficiently strong, has an excellent acid-resistance and can easily be manufactured, for use in such a process.

SUMMARY TO THE INVENTION

Accordingly, the present invention provides a hydrolysis of particulate lignocellulosic material with hydrochloric acid, characterized in that the hydrolysis is carried out in a hydrolysis reactor, which hydrolysis reactor comprises a cylindrical body with a wall structure of filament-wound composite, which reactor is provided with at least one inlet opening at one end of the cylindrical body and with at least one outlet opening at the opposite end of the cylindrical body; and a plastic lining inside the cylindrical body.

In addition, the present invention provides a hydrolysis reactor for the hydrolysis of particulate lignocellulosic material with hydrochloric acid, comprising

a cylindrical body with a wall structure of filament-wound composite, which reactor is provided with at least one inlet opening at one end of the cylindrical body and with at least one outlet opening at the opposite end of the cylindrical body; and

a plastic lining inside the cylindrical body.

The reactor according to the present invention provides high strength in view of the filament reinforcements. The plastics lining ensures an excellent acid-resistance. As the reactor has been manufactured by filament winding, the manufacture of the reactor is relatively easy and cheap. That ensures that the repair or replacement of any damaged reactor does not get prohibitively expensive. Moreover, the diameter of the cylindrical body may be much larger than for extruded plastic pipes. The diameter may be as large up to 10 m, which is much larger than the diameter according to the pipes in US 5028376.

Using such a reactor in the hydrolysis of particulate lignocellulosic material with hydrochloric acid, advantageously allows for a hydrolysis of particulate lignocellulosic material with hydrochloric acid that can be scaled up to higher volumes, is more robust, is more economic and/or has an improved HSE profile.

DETAILED DESCRIPTION OF THE INVENTION

The hydrolysis according to the invention may herein also be referred to as a method of hydrolysis of particulate lignocellulosic material with hydrochloric acid. The hydrolysis may suitably be part of a process comprising the hydrolysis of particulate lignocellulosic material with hydrochloric acid and optionally one or more other steps.

Preferably the hydrolysis is a hydrolysis of particulate lignocellulosic material with an aqueous hydrochloric acid solution, more preferably a concentrated aqueous hydrochloric acid solution. Such an aqueous hydrochloric acid solution preferably has a hydrochloric acid concentration of equal to or more than 15 %wt, more preferably of equal to or more than 30 wt%, based on the total weight of hydrochloric acid and water. For practical purposes the hydrochloric acid concentration may be equal to or less than 50 %wt, based on the total weight of hydrochloric acid and water. Preferably the hydrolysis is carried out a temperature in the range from equal to or more than 15°C to equal to or less than 30 °C. Preferably the hydrolysis is carried out at a pressure in the range from equal to or more than 0.5 bar (corresponding to 0.05 MegaPascal) to equal to or less than 5 bar (0.5 MegaPascal), more preferably a pressure in the range from equal to or more than 0.9 bar (corresponding to 0.09 MegaPascal) to equal to or less than 1 .1 bar (0.1 1 MegaPascal).

Preferably the hydrolysis comprises a pre-hydrolysis of particulate lignocellulosic material at a temperature in the range from equal to or more than 15°C to equal to or less than 30 °C with aqueous hydrochloric acid having an hydrochloric acid concentration of equal to or more than 34wt% to 37 %wt, based on the total weight of hydrochloric acid and water; and the pre-hydrolyzed lignocellulosic material is subsequently hydrolyzed in a main hydrolysis with aqueous hydrochloric acid having an hydrochloric acid concentration of equal to or more than 40%wt, based on the total weight of hydrochloric acid and water.

By a lignocellulosic material is herein understood a material containing at least cellulose, hemicellulose and lignin. By hydrolyzing, respectively hydrolysis, is herein understood the breaking of bonds between saccharide units in a polysaccharide, such as hemicellulose or cellulose, to yield monosaccharides, disaccharides and/or oligosaccharides (by oligo-saccharides are herein understood saccharide chains comprising in the range from 3 to 10 mono-saccharide units).

A wide variety of lignocellulosic materials can be used as feedstock. Examples of

lignocellulosic materials that may suitably be used include for example agricultural wastes such as stover (for example corn stover and soybean stover), corn cobs, rice straw, rice hulls, oat hulls, corn fibre, cereal straws such as wheat, barley, rye and oat straw; grasses; forestry products and/or forestry residues such as wood and wood-related materials such as sawdust and bark; waste paper; sugar processing residues such as bagasse and beet pulp; or mixtures thereof.

The lignocellulosic material may conveniently be washed, dried, roasted, torrefied and/or reduced in particle size before it is hydrolyzed. By a particulate lignocellulosic material is herein understood a lignocellulosic material that is present in the form of particles. The lignocellulosic material may conveniently be supplied or be present in a variety of forms, including chips, pellets, powder, chunks, briquettes, crushed particles, milled particles, ground particles or a combination of two or more of these. When the lignocellulosic material is wood, it is can for example be supplied or be present in the form of wood powder, wood chips, wood pellets, wood briquettes, wood chunks or a combination of two or more of these. The size of the particles may vary widely. For example the particulate lignocellulosic material may have a particle size distribution with a mean particle size diameter in the range from equal to or more than 1 .0 micron, more preferably equal to or more than 1 .0 millimeter, to equal to or less than 10.0 centimeter, more preferably equal to or less than 5.0 centimeter, still more preferably equal to or less than 2.0 centimeter. The particle size can for example be determined with the help of a Laser Diffraction Particle Size Analyzer (for example sold by Horiba).

The hydrolysis reactor comprises a cylindrical body that has a wall structure that has been made from a filament-wound composite. Preferably the cylindrical body comprises a wall structure that is formed by at least one band of resin-impregnated filaments. The resin can be selected from a range of thermosetting resins. Such suitable resins may be selected from the group consisting of epoxy resins, polyurethane resins, formaldehyde resins, vinyl ester resins, polyester resins, alkyd resins, copolymers thereof and mixtures thereof.

Examples of formaldehyde resins are phenol formaldehyde resins and melamine

formaldehyde resins. The resin-impregnated filaments can suitably be produced by contacting the resin and the filaments in any known manner. Such suitable manners include straying, brushing, dipping, impregnating, optionally under pressure, and similar manners. The resin may be liquid, but is preferably partially cured, so that the resin-impregnated filaments are not sticky. This facilitates the preparation of the cylindrical body by winding the filaments to form a filament-wound wall structure. After curing of the filament-wound wall structure a cylindrical body is obtained.

The filament-wound composite that forms the wall structure of the cylindrical body suitably comprises filaments. These filaments can suitably be composed of fibers. The filaments may be obtained straight from the manufacturing process for making the fibers. The fibers need not be made into a fabric. If a fabric is made, the fabric is conveniently prepared by techniques of weaving, knitting, braiding or stitching. The filaments can suitably be made of glass to result in a glass-reinforced filament-wound cylindrical body. Alternatively the filaments can be made of carbon fibers or polyamide fibers, in particular of aramide fibers. Therefore, the filament has preferably been made of glass, aramide, carbon or a mixture of two or more thereof.

The filament-wound composite forming the wall structure of the cylindrical body can be prepared in a known manner. An example of the preparation of a filament-wound vessel may be found in US 6361635. The preparation method described therein shows the fabrication of a vessel comprising a cylindrical body. The vessel may also comprise one or more dome-shaped ends. The hydrolysis reactor according to the invention may also comprise at least one dome-shaped end. US 6361635 shows that also dome shaped ends can be prepared by a process of winding resin-impregnated filaments. The process may suitably involve winding resin-impregnated filaments over a rotating mandrel. The winding may be done in a longitudinal, circumferential or, more preferably, in a helical manner, creating a filament-wound structure. The cylindrical body of the hydrolysis reactor preferably comprises filaments that have been wound in a helical fashion. After having wound the resin- impregnated filaments around the mandrel the resin is cured. The curing may be done thermally, by heating the filament-wound structure. Alternatively, the curing may be done via the addition of a catalyst or by the combination of catalyst addition and heating. After curing the mandrel may be removed, so that a hollow cylindrical body is obtained. It is

advantageous to construct the reactor in two or more pieces. Especially when the reactor is to be provided with a conical outlet it is advantageous to prepare a cylindrical body, optionally provided with an attachment means, such as a flange, and in addition a conical piece that can be fixed to the cylindrical body. By preparing the reactor in two or more pieces, the shapes of the individual pieces can easily be adjusted to the desires of the skilled person. Preferably, the hydrolysis reactor in the present inventions is provided with a conical piece on at least one end of the cylindrical body. Such a conical piece may facilitate the process of unloading the reactor contents.

The hydrolysis reactor according to the present invention is provided with a plastic lining. The plastic lining suitably comprises a layer of plastic material covering the inner surface of the cylindrical body that is in contact with the hydrochloric acid. The plastic lining is therefore suitably applied to the inner surface of the wall structure. For the material of the plastic lining any polymer that is resistant to hydrochloric acid can be used. The plastic lining may preferably have been made of a polymer selected from the group consisting of polyolefins, polyvinylchloride, chlorinated polyolefins, polyvinylidene chloride, polyvinylidene fluoride, polyvinylfluoride, polytetrafluoroethylene and mixtures thereof. When a polyolefin is used, the polyolefin preferably comprises polyethylene, polypropylene or a mixture thereof.

The plastic lining is different from a mere coating. The thickness of the plastic lining is suitably in the range of equal to or more than 1 millimeter (mm) to equal to or less than 10 mm. This thickness provides an adequate resistance to corrosion, whilst at the same time it provides some stiffness to the reactor.

The hydrolysis reactor according to the present invention may be fabricated in a manner similar to the preparation method of the vessel according to US 6361635. Thus, a mandrel may be provided over which the filaments are wound and cured. In this way a filament-wound cylindrical body is obtained. Subsequently, a plastic lining material may be applied at the inner side of the filament-wound cylindrical body, e.g. in the form of a liquid. It is evident that the application of a plastic lining in this manner is rather tedious. Preferably, the mandrel that is being used in the preparation of the filament-wound composite- comprising wall structure is made of the material that is to be used as the plastic lining. In this manner a sheet of the plastic lining material if formed into a mandrel and the edges are welded together, e.g. thermally or via solvent welding. The resin-impregnated filaments material are then wound around the mandrel in the shape of the cylindrical body. After curing of the resin the mandrel does not need to be removed, but it can be used as such in the hydrolysis reactor according to the present invention.

The thickness of the wall structure may be determined in accordance with the geometry of the reactor, e.g. its diameter and its height. Further, the thickness of the wall structure may be dependent on other circumstances that are applicable to the reactor such as density of the loading, pressures and temperatures applied, wind and seismic conditions etc. Preferably, the thickness of the wall structure of filament-wound composite is in the range of equal to or more than 1 mm to equal to or less than 100 mm, preferably from equal to or more than 5 mm to equal to or less than 80 mm. This thickness is in the same order of magnitude as the thickness of the pipes that are extruded in the process according to US 5028376. These pipes may have thickness of up to 3.2 inches (i.e. about 81 mm). As indicated above, the diameter of these pipes, though, is much smaller. The thickness of the wall structure can be easily adjusted to the desired value by adapting the desired number of windings of the resin-impregnated filament around the mandrel.

The hydrolysis reactor according to the present invention comprises a cylindrical body. The cross-section of the cylindrical body may have any desired shape. Such shapes include an elliptical, square or oblong shape. Most commonly, and preferably, the cross- section is a circle. Therefore preferably the cylindrical body is a circle-cylindrical body.

The hydrolysis reactor preferably comprises more than one inlet opening. One inlet opening is designed for the introduction of lignocellulosic material, such as wood chips or wood pellets, whereas a second inlet may be used for introducing a hydrolysis liquid. This hydrolysis liquid may suitably comprise the hydrochloric acid, for example as concentrated hydrochloric acid, suitably in an aqueous hydrochloric acid solution preferably has a hydrochloric acid concentration of equal to or more than 15 %wt. The hydrolysis reaction may suitably be carried out in a multitude of reactors, which reactors may be arranged in vertical or substantially vertical positions. Preferably, the lignocellulosic material may be introduced into all reactors from the upper inlet. The hydrolysis liquid, in particular concentrated hydrochloric acid, may be introduced into the first reactor either at a bottom inlet or via an upper inlet. At the opposite end of the hydrolysis reactor, the hydrolysis liquid, containing some hydrolysis products, is withdrawn from the reactor via an outlet for liquid. When the hydrolysis liquid is introduced into the first reactor via an upper inlet, the hydrolysis liquid with hydrolysis products is withdrawn at a lower outlet at the bottom of the reactor. The withdrawn hydrolysis liquid may subsequently be fed into a second reactor either via an upper inlet or via a lower inlet near the bottom of the reactor. It may be advantageous to keep the connecting tubes between the reactors as short as feasible and introduce the hydrolysis liquid at the lower inlet if the hydrolysis liquid has been withdrawn from the previous reactor via the lower outlet thereof. Alternatively, when the outlet for a hydrolysis liquid is arranged at the upper part of a hydrolysis reactor, the inlet for hydrolysis liquid at the subsequent reactor may then also be arranged at the upper part of this subsequent reactor. Accordingly the hydrolysis reactor of the present inventions preferably comprises at least an inlet opening for solids and an outlet opening for solids at opposite ends of the cylindrical body and at least a liquid inlet opening and a liquid outlet opening at opposite ends of the cylindrical body. From the above explanation it is evident that the inlet opening for solids and the liquid inlet opening do not need to be at the same side of the cylindrical body.

Suitably the above allows for a hydrolysis, wherein particulate lignocellulosic material can be introduced via the inlet opening for solids, whereas a hydrolysis liquid comprising hydrochloric acid can be introduced via the liquid inlet opening, and whereas, preferably simultaneous, at the opposite end of the hydrolysis reactor, the hydrolysis liquid, containing hydrolysis products, can be withdrawn from the reactor via the liquid outlet opening.

Solid residue remaining after the hydrolysis may suitably be unloaded via the outlet opening for solids. Preferably solid residue is unloaded via an outlet opening located at the lower part or at the bottom of the hydrolysis reactor. To avoid blocking of any potential liquid outlet opening that may also be located at the lower part or at the bottom of the hydrolysis reactor and/or to decrease the risk of bridging and/or rat holing of the solid residue during unloading, whilst preferably maintaining a liquid leak tight seal, a special design may be used for such outlet opening for solids. Preferably the hydrolysis reactor in the inventions therefore comprises an essentially spherical or hemispherical shaped valve, for example a ball valve or segmented ball valve, located at the at least one outlet opening for solids, preferably located at the lower part or at the bottom of the hydrolysis reactor. Especially the use of a segmented ball valve can be advantageous as such a valve may allow one to easily "cut through" the solid residue. Preferably such a ball valve or segmented ball valve is further used in combination with an annular cutting ring to protect the seats of the ball valve or segmented ball valve to prevent lignocellulosic material particles becoming trapped between the seat and the ball or segmented ball, causing wear/abrasion of the seat, resulting in leakage. The ball valve or segmented ball valve may suitably be supplied with a port. Such port may have different shapes and for example a circular port, slotted port or "v"-type port may be used.

It is preferred that the reactor is provided with a lid, which is suitably provided with a flange so that it may easily be connected to the cylindrical body. The at least one inlet opening is then suitably arranged in the lid. The inlet opening may be for the solids. However, it may also be the case that the lid covers the inlet opening for the solids, and that the opening that is provided in the lid may be used for the introduction of the hydrolysis liquid. Preferably, the at least one inlet opening is arranged in a lid that is provided with flanges to secure the lid to the cylindrical body.

The reactor that has been disclosed in EP 1878480 is arranged with a sieve plate to support solid lignocellulosic material.

It is advantageous for the hydrolysis reactor in the present inventions to also be provided with a sieve plate to support any solids that are introduced into the reactor.

Especially when the hydrolysis reactor comprises a cylindrical body and a conical piece, it is advantageous when the reactor is provided with a sieve plate between the cylindrical body and the conical piece or in the conical piece. In that way the withdrawal of the hydrolysis liquid at the lower part of the hydrolysis reactor is facilitated since the liquid is then

substantially free from solids.

Alternatively, the sieve plate can be arranged as an annular or conical perforated plate that is constructed at the bottom of the cylindrical body. The annular or conical perforated plate is then suitably surrounded by a cylindrical element that is provided with at least one liquid outlet opening. Preferably, the cylindrical element has also a wall structure of filament-wound composite with a plastic lining inside the cylindrical element.

A combination of a conical piece and a perforated plate is also possible. Such an embodiment resembles the reactor outlet shown in WO 2015/136044. This embodiment then suitably comprises a conical piece that at the wide end of the conical piece is suitably attached to the cylindrical body of the hydrolysis reactor, and at the opposite end of the conical piece is connected to a perforated plate, e.g. in the shape of a radial sieve. The perforations allow the hydrolysis liquid to pass through the plate so that the hydrolysis liquid containing hydrolysis products can be withdrawn substantially free from solids.

It is also possible to adjust the angle of any conical piece such that solid residue can advantageously be unloaded via an outlet opening for solids by gravity, without any solid residue remaining in the hydrolysis reactor and without any so-called rat-holing and/or bridging of the solid residue above an outlet valve, such as for example the spherical or hemispherical valve described above.

The hydrolysis reactor in the present inventions may therefore advantageously be provided

-with an conical piece; and/or

-with an ball valve or segmented ball valve;

at an outlet opening of the cylindrical body.

The hydrolysis reactor of the present invention may have a variety of sizes. Thanks to the high mechanical strength of the wall structure the size of the reactor can be very large. The large dimensions not only relate to the height of the reactor, but also to the inner diameter of the cylindrical body. When the cylindrical body has a circle as cross-section then the diameter is just twice the radius of the circle. When the cylindrical body has a different shape, the diameter is understood to mean the largest dimension of the cross-section of the cylindrical body. The cylindrical body may have a height in the range of 1 to 50 meter (m), preferably from 10 to 50 m, more preferably from 15 to 35 m. The cylindrical body may have an internal diameter in the range of 0.1 to 10 m, preferably from 2 to 10 m, more preferably from 3 to 8 m, and most preferably from 4 to 6 m. The filament-wound wall structure provides a mechanical strength that is sufficient to allow such sizes. However, it may be advantageous to arrange for a hydrolysis reactor that has a cylindrical body that consists of two or more modular elements. These modular elements are preferably connected by means of flanges. When one of the modular elements is damaged, e.g. when there is damage to the plastic lining of one of the elements, the skilled person may repair or replace only one single element. Moreover, the flanges provide an additional rim of material that gives additional mechanical strength to the wall structure of the cylindrical body.

The invention is illustrated by means of the Figure.

The Figure shows a hydrolysis reactor 1 which comprises a cylindrical body A, a dome-shaped end B and a conical piece C. The cylindrical body A comprises a plastic lining 2 and a filament-wound composite 3. The cylindrical body A has a circle-cylinder shape. The hydrolysis reactor is preferably used in a vertical or substantially vertical position. At the upper end, the cylindrical body extends into the dome-shaped end B, which is provided with an inlet opening for solids 4 and a liquid inlet opening 5. The dome-shaped end is also provided with a manhole 6. At the lower end of the cylindrical body A a conical piece C is attached. The Figure does not show the means via which the conical piece C has been attached. A suitable way to do so is by means of flanges that have been arranged at the cylindrical body and the conical piece. The hydrolysis reactor 1 is further provided with an outlet opening for solids 7 and a liquid outlet opening 8. The outlet opening 7 is provided with a flange 9 which can be used for connecting the reactor 1 with tubing for transporting the solids from the reactor to a further treatment.

Claims

1 . A hydrolysis of particulate lignocellulosic material with hydrochloric acid, characterized in that the hydrolysis is carried out in a hydrolysis reactor, which hydrolysis reactor comprises

- a cylindrical body with a wall structure of filament-wound composite, which reactor is provided with at least one inlet opening at one end of the cylindrical body and with at least one outlet opening at the opposite end of the cylindrical body; and

- a plastic lining inside the cylindrical body.

2. The hydrolysis according to claim 1 , wherein the cylindrical body comprises a wall structure formed by at least one band of resin-impregnated filament, wherein the resin- impregnated filament contains a resin selected from the group consisting of epoxy resins, polyurethane resins, formaldehyde resins, vinyl ester resins, polyester resins, alkyd resins, copolymers thereof and mixtures thereof.

3. The hydrolysis according to any one of claims 1 and 2, wherein the filament has been made of glass, aramide, carbon or a mixture of two or more thereof.

4. The hydrolysis according to any one of claims 1 to 3, wherein the plastic lining has been made of a polymer selected from the group consisting of polyolefins, polyvinylchloride, chlorinated polyolefins, polyvinylidene chloride, polyvinylidene fluoride, polyvinylfluoride, polytetrafluoroethylene, and mixtures thereof.

5. The hydrolysis according to any one of claims 1 to 4, wherein the cylindrical body has an internal diameter in the range of 0.1 to 10 m, preferably in the range of 2 to 10 m, more preferably of 3 to 8 m, and most preferably of 4 to 6 m and/or a height in the range of 1 to 50 m, preferably from 10 to 50 m, more preferably from 15 to 35 m.

6. The hydrolysis according to any one of claims 1 to 5, wherein the hydrolysis reactor comprises at least an inlet opening for solids and an outlet opening for solids at opposite ends of the cylindrical body and at least a liquid inlet opening and a liquid outlet opening at opposite ends of the cylindrical body, and

wherein particulate lignocellulosic material is introduced via the inlet opening for solids, whereas a hydrolysis liquid comprising hydrochloric acid is introduced via the liquid inlet opening, and whereas at the opposite end of the hydrolysis reactor, the hydrolysis liquid, containing hydrolysis products, is withdrawn from the reactor via the liquid outlet opening.

7. A hydrolysis reactor for the hydrolysis of particulate lignocellulosic material with hydrochloric acid, comprising

- a plastic lining inside the cylindrical body.

8. The hydrolysis reactor according to claim 7, wherein the cylindrical body comprises a wall structure formed by at least one band of resin-impregnated filament, wherein the resin- impregnated filament contains a resin selected from the group consisting of epoxy resins, polyurethane resins, formaldehyde resins, vinyl ester resins, polyester resins, alkyd resins, copolymers thereof and mixtures thereof.

9. The hydrolysis reactor according to any one of claims 7 and 8, wherein the filament has been made of glass, aramide, carbon or a mixture of two or more thereof.

10. The hydrolysis reactor according to any one of claims 7 to 9, wherein the plastic lining has been made of a polymer selected from the group consisting of polyolefins, polyvinylchloride, chlorinated polyolefins, polyvinylidene chloride, polyvinylidene fluoride, polyvinylfluoride, polytetrafluoroethylene, and mixtures thereof.

1 1 . The hydrolysis reactor according to any one of claims 7 to 10, wherein the thickness of the plastic lining is in the range of 1 to 10 mm.

12. The hydrolysis reactor according to any one of claim 7 to 1 1 , wherein the thickness of the wall structure of filament-wound composite is in the range of 1 to 100 mm.

13. The hydrolysis reactor according to any one of claims 7 to 12, which is provided with a conical piece; and/or

with a ball valve or segmented ball valve;

at an outlet opening of the cylindrical body.

14. The hydrolysis reactor according to any one of claims 7 to 13, which reactor comprises at least an inlet opening for solids and an outlet opening for solids at opposite ends of the cylindrical body and at least a liquid inlet opening and a liquid outlet opening at opposite ends of the cylindrical body.

15. The hydrolysis reactor according to any one of claims 7 to 14, wherein the cylindrical body consists of two or more modular elements and wherein the modular elements are preferably connected by means of flanges.

16. Use of a hydrolysis reactor according to any one of claims 7 to 15 in the hydrolysis of particulate lignocellulosic material with hydrochloric acid.