FIELD OF THE INVENTION

[001 ] The present disclosure relates to a method for the treatment of different types of solid/fluid mixtures. The present disclosure is broadly concerned with solid/fluid separation apparatus, in particular improved screw press devices of a highly versatile nature which can be used for the separation of a wide variety of liquid/solid mixtures and slurries of varying densities, solids contents and types of solids and liquids. BACKGROUND OF THE INVENTION

[002] Various process feed or process residue treatment processes for solid/liquid separation are known which require significant residence time, high pressure and high temperature. Generally, liquids must be separated from treated solids at those conditions. Conventional liquid/solid separation equipment is not satisfactory for the achievement of high liquids/solids separation rates and solids with low liquid content.

[003] A key component of process efficiency in the pretreatment of

lignocellulosic biomass is the ability to wash and squeeze hydrolyzed hemi-cellulose sugars, toxins, inhibitors and/or other extractives from the solid biomass/cellulose fraction. It is difficult to effectively separate solids from liquid under the high heat and pressure required for cellulose pre-treatment.

[004] Many biomass to ethanol processes generate a wet fiber slurry from which dissolved compounds and liquid must be separated at various process steps to isolate a solid fibrous portion. Solid/liquid separation is generally done by filtration and either in batch operation, with filter presses, or continuously by way of screw presses.

[005] Solid/liquid separation is also necessary in many other commercial processes, such as food processing (oil extraction), reduction of waste stream volume in wet extraction processes, dewatering processes, suspended solids removal.

[006] Commercial screw presses can be used to remove moisture from a solid/liquid slurry. However, the remaining de-liquefied solids cake generally contains only 40-50% solids. This level of separation may be satisfactory when the filtration step is followed by another dilution or treatment step, but not when maximum dewatering of the slurry is desired, the leftover moisture being predominantly water. This unsatisfactory low solids content is due to the relatively low maximum pressure conventional screw presses can handle, which is generally not more than about 100- 150 psig of separation pressure. Commercial Modular Screw Devices (MSD's) combined with drainer screws can be used, which can run at higher pressures of up to 300 psi. However, their drawbacks are their inherent cost, complexity and continued filter cake limitation of no more than 50% solids content.

[007] During solid/fluid separation, the amount of liquid remaining in the solid fraction is dependent on the amount of separating pressure applied, the thickness of the solids cake, and the porosity of the filter. The porosity of the filter is dependent on the number and size of the filter pores. A reduction in pressure, an increase in cake thickness or a decrease in porosity of the filter, will all result in a decrease in the degree of liquid/solid separation and the ultimate degree of dryness of the solid fraction.

[008] For a particular solids cake thickness and filter porosity, maximum separation is achieved at the highest separating pressure possible. For a particular solids cake thickness and separating pressure, maximum separation is dependent solely on the pore size of the filter.

[009] High separating pressures unfortunately require strong filter media, which are able to withstand the separating pressure, making the process difficult and the required equipment very costly. When high separating pressures are required, the thickness of the filter media needs to be increased to withstand those pressures.

However, to maintain the same overall porosity as the filter with the thinner filter media, thicker filter media require a larger pore size. This may create a problem, depending on the solids to be retained, since the acceptable pore size of the filter is limited by the size of the fibers and particles in the solids fraction, the clarity of the liquid fraction being limited solely by the pore size of the filter media. Pores that are too large allow a significant amount of suspended particles to collect in the liquid fraction, thereby reducing the liquid/solid separation efficiency and potentially lead to plugging of downstream equipment.

[0010] Over time, filter media tend to plug with suspended solids reducing their production rate, especially at the high pressures required for cellulose pre-treatment. Thus, a backwash flow of liquid is normally required to clear a blockage and restore the production rate. Once a filter becomes plugged, it takes high pressure to backwash the media. This is particularly problematic when working with filter media operating at pressures above 1000 psig with a process that is to be continuous to maximize the production rate and to obtain high cellulose pre-treatment process efficiency. The current equipment required to effectively perform cellulose pre-treatment is both complex and expensive as there is no known equipment available for simultaneously carrying out multiple lignocellulosic biomass pretreatment steps in a single apparatus. [0011] Conventional single, twin, or triple screw extruders do not have the residence time necessary for low energy pre-treatment of biomass, and also do not have useful and efficient solid fluid separating devices for the pre-treatment of biomass. United States Patents US 3,230,865 and US 7,347,140 disclose screw presses with a perforated casing. Operating pressures of such a screw press are low, due to the low strength of the perforated casing. United States Patent US 5,515,776 discloses a worm press and drainage perforations in the press jacket, which increase in cross-sectional area in flow direction of the drained liquid. United States Patent US 7,357,074 is directed to a screw press with a conical dewatering housing with a plurality of perforations for the drainage of water from bulk solids compressed in the press. Again, a perforated casing or jacket is used. As will be readily understood, the higher the number of perforations in the housing, the lower the pressure resistance of the housing. Moreover, drilling perforations in a housing or press jacket is associated with serious challenges when very small apertures are desired for the separation of fine solids.

[0012] Published U.S. Application US 2012/01 185 7 discloses a solid/fluid separation module with high porosity for separation at elevated pressures. The f Iter module includes filter packs respectively made of a pair of plates that create a drainage system. A f Iter plate with slots creates flow channels for the liquid to be removed and a backer plate creates the support for containing the internal pressure of the solids during the squeezing action and for creating a drainage passage for the flow channels. The starting material, which is to be separated under pressure, determines the pore size required for continuous operation. Theoretically, the filter pore size must be smaller than the smallest particles or fibers found in the starting material to prevent clogging of the filter. In the module including the filter and backer plates, the filter pore size is adjusted by the thickness of the filter plate and/or the width of the drainage channels or slots in the filter plate. However, material strength and manufacturing processes set practical limits to the lower end of pore size spectrum. To minimize pore size, both the filter plate thickness and the drainage slot width must be minimized. However, regardless of the process used for cutting the slots in the filter plate, the practical limit on the thickness of the flow channel plate is in the range of about 0.005". Although the plate thickness can theoretically be less, distortion of filter plates of minimum thickness during cutting of the slots and/or during installation into the f Iter module may occur. Moreover, the manufacture of the f Iter plates is difficult and cost intensive and the need for two different types of plates increases the manufacturing costs for the filter module. In addition, since the minimum thickness of the filter plate practically sets the lower limit for the width of the drainage channels many non-fibrous water/solids mixtures, wherein the solids are significantly less than 0.005" in diameter, may not be reliably separated by this module and may be pushed through the module without significant separation, especially at high separation pressures. Thus, an improved solid/f uid separation device is desired.

SUMMARY OF THE INVENTION

[0013] It is an object of the present disclosure to obviate or mitigate at least one disadvantage of previous solid/liquid separation devices.

[0014] In one embodiment, the present disclosure provides a solid/fluid separating module for separating a pressurized mass of fluid containing solids, including a fluid collection chamber and at least one f Iter unit for separating fluid from the pressurized mass and guiding separated fluid into the fluid collection chamber. The filter unit defines a core opening sealed from the collection chamber for receiving the pressurized mass and includes a filter pack consisting of at least one filter plate and a backer plate stacked against each filter plate, all f Iter and backer plates having the core opening and each filter plate having a plurality of protrusions for maintaining the stacked backer plate in a spaced apart parallel ohentation to the filter plate, to create an intermediate filter gap between the filter plate and the stacked backer plate, the f Iter gap extending from the core opening to the fluid collection chamber, the protrusions being localized deformations of the filter plate body.

[0015] In another embodiment, the present disclosure provides a solid/fluid separating module for separating a pressurized mass of fluid containing solids, including a fluid collection chamber and at least one filter unit for separating fluid from the pressurized mass and guiding separated fluid into the fluid collection chamber. The filter unit def nes a core opening sealed from the collection chamber for receiving the pressurized mass and includes a filter pack consisting of at least two stacked filter plates, each having the core opening and each having a plurality of protrusions for maintaining the stacked f Iter plates in a spaced apart parallel orientation to create between the filter plates an intermediate filter gap extending from the core opening to the uid collection chamber.

[0016] In yet another embodiment, the present disclosure provides a solid/fluid separating module for separating a pressurized mass of fluid containing solids, including a fuid collection chamber and at least one filter unit for separating fluid from the pressurized mass and guiding separated fluid into the fluid collection chamber. The filter unit defines a core opening sealed from the collection chamber for receiving the pressurized mass and includes a filter pack consisting of a plurality of stacked filter plates, each having the core opening and each having a plurality of protrusions for maintaining each filter plate in a spaced apart parallel orientation to each directly adjacent, stacked filter plate to create between respectively adjacent filter plates an intermediate filter gap extending from the core opening to the fluid collection chamber.

[0017] All filter plates in the filter unit are preferably identical. The protrusions of the filter plate are preferably achieved by repousse or by pressing, stamping or embossing on one face of the filter plate to create a protrusion on the opposite face. All such protrusions will be referred to in the following as stamped through protrusions. The protrusions are preferably present on one face of the filter plates, but may also be present on both faces of the filter plates. Instead of creating the protrusions by metal working, the protrusions may also be adhered to one or both faces of the filter plate and may be sprayed-on, rolled-on, or the like.

[0018] When the protrusions are of the stamped through type, identical plates will nest one in the other when stacked, since the protrusions on one face of the filter plate will fit into the associated dimples on the opposite face. Thus, in order to allow stacking of the filter plates without nesting, the protrusions are preferably placed in a rotation or mirror asymmetrical pattern of protrusions and flats in which a f rst location including one of a protrusion and a flat is always associated with a rotation or reflection symmetrical, second location including the other of the protrusion and the flat. By using such an arrangement a single filter plate design can be used to create a filter plate stack by simply rotating or flipping and rotating every second filter plate in the stack until the core opening is aligned.

[0019] In another approach to avoiding nesting, the protrusions themselves are shaped to have a rotation or reflection asymmetrical shape or orientation, so that upon rotation or flipping of the plate the projections will not nest within one another. This is achieved by shaping the protrusions so that a protrusion of a first shape or orientation at a first location is always associated with a protrusion of non-congruent shape or orientation at a rotation or reflection symmetrical, second location. This will avoid the need for placing the protrusions in an asymmetrical pattern as described above, since even overlapping protrusions will not nest after rotation or flipping of the filter plate.

[0020] The use of protrusions on the filter plate has several advantages over machined or cut drainage channels in the f Iter plate. Drainage channel size can be controlled by the protrusion height and is independent of the filter plate thickness. Thus, filter pore sizes significantly smaller than the minimum f Iter plate thickness can be achieved. If the symmetrical, staggered pattern of protrusions is used, or protrusions of asymmetrical shape, a single filter plate design can be used for all filter plates and backer plates are obviated. Manufacturing and assembly costs are signif cantly reduced with a filter pack including only a single plate type. Moreover, the pore size and porosity of a filter block including a single style of plate can be easily controlled by the height of the protrusions and the thickness of the plates, respectively. A lower cost of manufacturing is achieved with the single plate design since only one style of plate is required for a particular filter fineness, porosity and strength. Also contributing to this lower cost of manufacturing is the ability to use a single basic stamping/embossing die for a particular core opening size to create a wide array of drainage heights and porosity factors by varying the depth of the stamping which in turn forms various drainage channels heights.

[002 1] By combining plate thickness and the depth and style of the embossed shape on the plate, a wide variety of filters can be created. Drainage heights as low as 0.0001 ° and as high as 0.150" with plate thickness from 0.005 ¹ ' to 0.030" can be designed to create filter strengths from 100 psig to 20,000 psig. Filter porosities can range from as little as 2% for the extremely fine ultralow height drainage channel of 0.0001" (2.54 micron), which provides a very strong filter with a pressure capacity of up to 20,000 psig. Conversely at the other end of the spectrum, porosities of up to 91 % for much larger drainage channels of 0.050° with a thin 0.005" wall plate height can be achieved, which will have a lower pressure capacity of about 100 psig.

[0022] This wide range of f Iter fineness (pore size), porosity and strength can be combined in a single screw press style dewatering machine (single, double or triple shaft) to dewater materials in the range of 10% solids (90% water) to 80% solids (20% water) in one continuous press. This can be accomplished by using a series of filters of progressively decreasing pore size and porosity along the length of the screw press. The more porous filters of lower strength at the beginning of the screw conveying elements remove the easiest liquid at the lowest pressure, while the ner filters of higher strength at the end of the conveying sections separate the last remnants of water for which the highest pressure is required.

[0023] To achieve maximum dryness of the solid/fluid mixture, it is desirable to minimize filter pore size while maximizing internal pressures. Minimizing pore size is achieved by the width of the drainage gap between plates which is a function of plate thickness in the filter module of Published U.S. Application US 2012/0 18517. This practical limit of plate thickness to define pore size has now been addressed by the inventors by the use of a single filter plate with protrusions. In the filter unit of the present invention, filter pores are formed by the protrusions, which can be efficiently manufactured, for example, by simply embossing a 3 dimensional shape into a single filter plate, which is simpler than the cutting of filter slots into the filter plates as in Published U.S. Application US 2012/0118517. Instead of slots with heights of the finger plate thickness, the drainage passageways between the filter plates achievable with the filter unit in accordance with the present disclosure are independent of the filter plate thickness and are dependent solely on the height of the protrusions. For example, by using a filter plate of 0.005 inch thickness and stamping 3 dimensional "dimples" that are 0.002" deep will create protrusions of 0.002" height and, thus, drainage canals with a width of 0.002". Even smaller drainage channel widths down to 0.0001" (2.54 microns) can be achieved by embossing plates with a "pricking" design and other styles of dimples or grooves can create drainage channels heights up to 0.100" high depending on the embossing pattern and the thickness of the plate.

[0024] All existing functions of the prior art dual plate system (filter and backer plates) of Published U.S. Application US 2012/0118517 can be achieved with the single 3 dimensional plate system of the present disclosure, including all solid, liquid and gas separation capabilities due to filter strength for squeezing, porosity, liquid or gas pressure collection and self-cleaning capability, while even smaller pore sizes can be achieved.

[0025] The preferred screw press style unit of the solid/liquid separation apparatus of the present disclosure includes a twin screw assembly having a barrel housing a pair of parallel or non-parallel screws with at least partially intercalated flighting. The flighting of the screws is intercalated at least along a part of the length of the extruder barrel to define a close clearance between the pair of screws and between the screws and the f Iter or solid barrel opening. The close clearance reduces reverse slippage of the material backward while conveying forward.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] For a better understanding of the embodiments described herein and to show more clearly how they may be earned into effect, reference will now be made, by way of example only, to the accompanying drawings which show the exemplary embodiments and in which:

[0027] Figure 1 shows a schematic view of an exemplary cellulose pre-treatment system schematically incorporating a twin screw extruder with solid-liquid separation module;

[0028] FIG. 1 a is a partially schematic side elevational view of an exemplary solid/fluid separating apparatus in accordance with the invention; [0029] FIG. 2 is a fragmentary horizontal sectional view of an exemplary apparatus as shown in of FIG. 1a, but including only one solid/liquid separation module, for reasons of simplicity;

[0030] FIG. 3 is a vertical sectional view of an exemplary apparatus as shown in of FIG. 1 a, but including only one solid/liquid separation module, for reasons of simplicity;

[0031] FIG. 4a is a perspective view of the preferred tapered twin extrusion screw set used in the exemplary embodiment of Figure 1a;

[0032] FIG. 4b is a plan view of a non-tapered twin extrusion screw set, which may be used in the exemplary embodiment of Figure 1 a together with a cylindrical barrel;

[0033] Figure 5a schematically illustrates an embodiment of a solid/fluid separation module in exploded view;

[0034] Figure 5b shows an exploded view of the solid/fl utd separation module shown in Figure 5a;

[0035] Figure 6A shows a filter plate of the separation module having multiple protrusions for generating a spacing with adjacent filter plates;

[0036] Figure 6B shows the filter plate of Figure 6A rotated by 180 degrees about its center;

[0037] Figure 7A shows the filter plate of Figure 6A flipped over and rotated by 90 degrees;

[0038] Figure 7B shows the filter plate of Figure 7A rotated by 180 degrees about its center;

[0039] Figure 8A shows a filter plate of the separation module having multiple protrusions of reflection or rotation asymmetrical shape for generating a spacing with adjacent filter plates;

[0040] Figure 8B shows the filter plate of Figure 8A rotated by 180 degrees about its center;

[0041] Figure 9A shows the filter plate of Figure 8A flipped over and rotated by 90 degrees;

[0042] Figure 9B shows the filter plate of Figure 9A rotated by 180 degrees about its center;

[0043] Figure 10 is a cross-sectional view of a stack filter plates made of alternating filter plates of Figures 6A and 6B;

[0044] Figure 1 shows the particle size distribution of the particles found in a filtrate obtained with one embodiment of the separation module;

[0045] Figure 12 illustrates the applicability of a separation device in accordance with the present disclosure for the extraction of water and oil from olives feed stock;

S [0046] Figure 13 illustrates the applicability of a separation device in accordance with the present disclosure for the extraction of sucrose solution from sugar beets feed stock;

[0047] Figure 14 illustrates the applicability of a separation device in accordance with the present disclosure for the extraction of oil and water from macerated soybean feed stock; and

[0048] Figure 15 illustrates the applicability of a separation device in accordance with the present disclosure for the extraction of water from pretreated lignocelluiostc biomass feed stock.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] It will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the f gures to indicate corresponding or analogous elements or steps. In addition, numerous specific details are set forth in order to provide a thorough understanding of the exemplary embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practiced without these specif c details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the embodiments described herein.

Furthermore, this description is not to be considered as limiting the scope of the embodiments described herein in any way, but rather as merely descri ing the implementation of the various embodiments described herein.

[0050] The preferred extruder unit of the present disclosure includes a twin screw assembly having parallel or non-parallel screws with the flighting of the screws intercalated at least along a part of the length of the extruder barrel to define close- clearance between the screws and the screws and the barrel. Screw extruders with more than two extruder screws can also be used. Cylindrical or tapered, conical screws can be used. Preferred are tapered, conical screws, most preferably non-parallel conical screws. The close clearance creates nip areas with increased shear. The nip areas create high pressure zones within the barrel which propel material forwardly, while the material is kneaded and/or sheared, if required. A specialized fluid separation unit is also provided, which allows fluids to be efficiently extracted from the extruded mixture.

[0051] The inventors developed a solid-liquid filtering device for use with a screw press conveyor, which filtering device can handle very high pressures (up to 20,000 psig) and surprisingly was able to generate solids levels from 50 -91 % well beyond that of anything commercially available or applied in the laboratory, when combined with a twin- screw extruder press. In addition, the liquid portion extracted contained little suspended solids, due to the very small pore size of the device, which provides additional benefit. The combination of a high pressure filtering u it with a twin-screw extruder press resulted in a solid/liquid separation device able to develop virtually dry cake. The twin screw is able to shear the material with a very thin cake layer at pressures far exceeding 300 psi while at the same time allowing trapped and bound liquid and water a path to migrate out of the solids and out of the apparatus through the novel filter device.

[0052] With the apparatus of the invention, one can apply significant shear forces/stresses to a fluid containing both liquids and solids, which forces are applied in a thin cake within a very strong and very fine filtering mechanism (strength of the filtering unit of up to 20,000 psi, with pores sizes down to 0.1 microns at temperatures up to 500C), which at the same time allows the freeing up of liquid to migrate out through this fine filter. Thus, it is expected that the combination of this filter unit with a twin-screw extruder press will provide significant benefits to a cellulosic ethanol process and to other processes, especially those dealing with the dewatering of Non-Newtonian Fluids which have shear thinning characteristics or a viscoplastic material which breaks down in separate solid and liquid components once a specific shear stress is imparted to the material.

[0053] Turning now to the drawings, FIG. 1a schematically illustrates an exemplary solid fluid separating apparatus 200 in accordance with the invention. The apparatus includes a twin-screw extruder 210 with barrel modules 212 and separation modules 214, which extruder 2 0 is driven by a motor 226 through an intermediate gear box drive 224, both the motor and gear box being conventional components.

[0054] FIGs. 2 and 3 illustrate a simplified exemplary embodiment of the apparatus shown in FIG. 1 a, including only a single separating module 214. As is apparent from FIGs. 2 and 3, the apparatus 200 broadly includes a sectionalized barrel 216 presenting an inlet 218 and an outlet 220, with a specialized twin screw assembly 222 within the barrel 216; the assembly 222 is coupled via the gear box drive 224 to the motor 226. The barrel 216 in the simplified exemplary embodiment illustrated is made up of two end-to-end interconnected tubular barrel heads 228, 230, and a separating module 232. Each barrel head is provided with an external jacket 234, 236, to allow circulation of cooling or heating media for temperature control of the extruder device. The separating module 232 includes an external pressure chamber 238. The first head 228 includes the inlet 218. To produce the desired back pressure in the barrel 2 6 and the separating module 238, the separating module 238 may include a die 240 with a central opening, the width of which determines the back pressure. However, the pressure in the barrel 216 and the separating module 238 is preferably controlled by the fit between the screws 250, 252 and the barrel 216 and the rotational speed of the motor 226 and, thus, the screws 250, 252. Each of the heads 228-230 also includes an internal sleeve 242, 244 which cooperatively define continuous screw assembly-receiving opening 248 within the barrel, which opening may be tapered to accommodate tapered screws. This opening 248 has a generally "figure eight" shape in order to accommodate the screw assembly 222. As illustrated, the opening 248 is widest at the rear end of head 228 and progressively and uniformly tapers to the end of the apparatus at the outlet 220 of the barrel 216.

[0055] The screw assembly 222 includes first and second elongated screws 250, 252 which are in side-by-side relationship as best seen in FIG. 4a. If a non-tapered barrel of constant cross-section is used (not shown), a pair of straight or cylindrical screws as shown in FIG. 4b can be used as screws 250 and 252. Each of the screws 250, 252 includes an elongated central shaft 254, 256 as well as outwardly extending helical flighting 258, 260. In the tapered screws as shown in FIGS. 2 and 3, the shafts 254, 256 each have an outer surface which is progressively and uniformly tapered through a first taper angle from points 262, 264 proximal to the rear ends of the corresponding shafts 254, 256, to forward points 266, 268 adjacent the forward ends of the shafts. This taper angle generally varies from about 0.5-5°, and more preferably from about 1-2.2°. The illustrated embodiment has a taper angle of 1.3424°.

[0056] The ighting 258, 260 (in the embodiment illustrated double flights are used, but single or multiple flights are also a possibility) extends essentially the full length of the shafts 252, 254 between points 262, 266 and 264, 268. Thus, the flighting 258, 260 proceeds from a rear end adjacent the point 262, 264 in a continuous fashion to the forward point 266, 268. In addition, the flighting presents an outer surface 270, 272 on each of the screws 250, 252. The geometry of the flighting 258, 260 is such that the flight depth progressively and uniformly decreases as the flighting proceeds from the rear end to the front end of the screws 250, 252. Consequently, the outer surfaces 270, 272 of the flighting 258, 260 also taper from rear to front in a progressive and uniform fashion. The second angle of taper of the flighting depth and the outer flighting surfaces can range from 2-6° and in the illustrated embodiment is 3.304°.

[0057] Finally, the ighting 258, 260 is designed so that the width of the flighting outer surfaces 270, 272 increases in a progressive and uniform fashion from the rear end of the screws to the front ends thereof. This configuration is best illustrated in FIGS. 3 and 4a, where it will be seen that the width is relatively small at the rear ends of the screws 250, 252, but increases to a wider width at the forward ends of the screws. As indicated previously however, the width may be constant throughout the length of the screws, or could narrow from the rearward ends to the forward ends thereof. Accordingly, the ratio of the width at the forward or input end of each screw to the width at the rearward or output end may range from about 0.5 to 5.

[0058] The screws 250, 252 are preferably oriented so that their respective center axes are at a converging angle relative to each other, so that an included angle is defined by the center axes. This included angle may range from about 1-8°. The included angle in the illustrated embodiment is 2.3240°. When the screws 250, 252 are oriented as described within barrel opening 248, the flighting 258, 260 of the respective screws 250, 252 is intercalated, i.e., each of the flightings defines an imaginary frustum of a cone between the rear and front ends of the corresponding screws, and the flighting 258, 260 extends within the imaginary frustum of the adjacent screw. As shown, and by virtue of the selection of appropriate first and second taper angles and the included angle between the center axes 274, 276, the flighting presents a plurality of close-clearance nip zones 278 along the length of the screw assembly 222. These nip areas present a clearance between the flightings 258, 260 which is preferably substantially constant along the length of the screw assembly 222. More generally, if desired such nip clearances could increase or decrease along the length of the assembly 222. In addition to the nip areas 278, it will be observed that the assembly 222 also presents material backflow passageways 280 and kneading zones 282 between the screws 250, 252.

[0059] During operation, the mixture to be separated is passed into and through the extruder device 214. The screw assembly 222 is rotated so as to co-rotate the screws 250, 252, usually at a speed of from about 20-1 ,200 rpm. Pressures within the extruder are usually at a maximum just adjacent the outlet, and usually range from about 300- 20,000 psig, more preferably from about 1 ,000-10,000 psig. Maximum temperatures within the extruder normally range from about 40-500° C.

[0060] Extrusion conditions are created within the device 214 so that the product emerging from the extruder barrel usually has a higher solids content, than the product fed into the extruder. The preferred solids content to be achieved in biofuel production from lignocellulosic biomass to be achieved with the separation device of this disclosure is above 50%.

[0061] During passage of the extrudable mixture through the barrel 2 6, the screw assembly 222 acts on the mixture to create, together with the endmost die 240, if present, or the fit with the barrel 2 6, the desired pressure for separation. The specific configuration of the screws 252, 254 as described above generates separating conditions not heretofore found with conventional screw presses. That is, as the mixture is advanced along the length of the co-rotating screws 252, 254, it continually encounters the alternately upper and lower close-clearance nip areas 278 which generate relatively high localized pressures serving to push or "pump" the material forwardly; at the same time, the product is kneaded within the zones 282 as the screws rotate, and backflow of material is allowed through the passageways 280. The result is an intense

mixing/shearing and cooking action within the barrel 216. Furthermore, it has been found that a wide variety of solid/liquid mixtures may be separated using the equipment of the invention; simply by changing the rotational speed of the screw assembly 222 and, as necessary, temperature conditions within the barrel, which means merely by changing the operational characteristics of the apparatus. This degree of flexibility and versatility is unprecedented in the filtration art.

[0062] One embodiment of a membrane-free solid/fluid separator module 100 in accordance with the present disclosure is shown in Figures 5 and 5a, which module is capable of withstanding very high internal pressure forces (up to 5000 psig). This solid/fluid separator module can be used with the process and apparatus shown in Figure 1 while being able to control the permeability/porosity (filtration capability) by various filter plate configurations and plate thicknesses as required by the type of biomass/solids treated.

[0063] An exemplary embodiment of the separation module 214, as illustrated in

Figure 1 a, is shown in more detail in Figure 2 as solid/fluid separation module 100. It is used as part of the solid/liquid separating apparatus of Figure la and is mounted between the twin screw extruder barrel (from here on barrel 500 and an extruder block 520. The module 100 separates fluids (liquid and/or gas) from a liquid containing mass of solids compressed by the screw press, preferably to pressures above 100 psig. The separation module 100 includes a collection chamber 200 and a filter unit 300 having a porosity of 2% to 91 % (total pore area relative to the total filter surface). Preferably, the module 100 withstands operating pressures up to 20,000 psig at a filter porosity of 2 to 91 %. The filter unit 300 preferably includes a plurality of filter pores with a pore size of 0.0001 " to 0.05".

[0064] In a preferred embodiment, the filter unit 300 includes filter pores having a pore size of 0.002" for the separation of f ne solids, a porosity of 29% (filter plate thickness 0.005"; 0.00270.002"+0.005") and a pressure resistance of 1500 psig. In another embodiment, the filter unit 300 includes filter plates of 0.005" thickness and filter pores having a pore size of 0.0001 ", resulting in a porosity of 2%. In a further preferred embodiment, the filter unit 300 includes filter plates of 0.005" thickness, filter pores of a pore size of 0.05", resulting in a porosity of 91 %. [0065] The basic construction of the separation module 100 is shown in Figures 2 and 3. A collection chamber 200, which is capable of withstanding the highest pressure of any component is used to separate the filtered out fluids into gases and liquid. The collection chamber is defined by a pressure jacket or housing 220 and intake and output end plates 230 and 240. Liquid can be drained from the collection chamber 200 through a liquid drain 221 , preferably located at the lowest point on the pressure jacket 220. The pressure jacket 220 further includes a plurality of alignment ridges 223 extending parallel to a longitudinal axis of the jacket on the inside of the jacket, for alignment of the filter and backer plates within the collection chamber 200. Gas accumulated in the collection chamber 200 can be exhausted from the chamber through a gas drain 222, preferably located at the highest point on the pressure jacket 220. The high pressure collection chamber 200 is sealed by way of circular seals 250 positioned between axial ends of the pressure jacket 220 and the end plates 230, 240. This high pressure / high temperature capability allows for washing of biomass with fluids such as ammonia, C02 and water which are normally in the gaseous state at process operating temperatures of 50 to 250°C pressures. The separation module is fastened together by assembly bolts 225 located outside the pressure jacket 220 for pulling the end plates 230, 240 together and clamping the pressure jacket 220 and circular seals 250 therebetween. Filter unit clamping bolts 129 (see Figure 2) can also be used to clamp together the filter packs 321 , 322 in the filter unit 300. In a preferred embodiment, the filter unit clamping bolts extent through the end plates 230, 240 and provide for additional clamping together of the separation module 200. The f Iter unit clamping bolts 129 can also extend through the extruder block 520 for fastening of the extruder block to the separation module. However, to minimize the number of penetration points in the separation module 200 which need to be reliably sealed for maintaining a pressure in the collection chamber 200, the filter unit fastening bolts 129 are omitted and all clamping together of the pieces of the separation unit is achieved by fastening structures, such as bolts 225, located outside the pressure jacket. Depending on the pressures used, some gases can be separated right in the collection chamber 200, or in some circumstances (as shown in Figure 1 ) a separate flash vessel can be utilized to optimize the overall efficiency of the process.

[0066] The f Iter unit 300 includes several plate blocks 320 assembled from a stack of the basic filter plates 120 of the invention, which are described in more detail below with reference to Figures 6A, 6B, 7A, 7B, 8A, 8B, 9A and 9B. There are right hand filter packs 32 including filter plates 120 in their normal and rotated orientations, whereby in the rotated orientation the filter plate 120 is rotated by 180 degrees from the normal orientation, and left hand filter packs 322 including a filter plate 160 in normal and rotated orientation, wherein the filter plate 160 in the normal orientation is a filter plate 120 flipped over and rotated by 90 degrees.

[0067] In one aspect, the separation module includes a pressurizable collection chamber 200 and a filter unit 300 for sealingly receiving the pressurized mass (not shown). The filter unit 300 has a preselected filter pore size and a preselected porosity. The filter unit 300 includes at least one pair of stacked filter plates 120, 120', whereby filter plate 120' is identical to filter plate 120, but rotated by 180 degrees in the plane of the plate. Preferably, a plurality of f Iter plates 120, 120' are altematingly stacked in the filter plate stack. The filter plates 120, 120' have opposite front and back faces 121 , 123, a front cover plate 230 engaging the front face 121 of the first filter plate 120 in the stack and a rear cover plate 240 engaging the back face 123 of the last filter plate 120' in the stack. The filter and cover plates (120, 120', 230, 240) define a throughgoing core opening 128 sealed from the collection chamber 200 for receiving the pressurized mass (not shown). The filter plate 120 has multiple protrusions 132 protruding from the front face 121 for maintaining an adjacent filter plate 120' in a spaced apart parallel orientation to the filter plate 120 and to create an intermediate f Iter gap between the filter plates 120, 120', which filter gap extends from the core opening 128 to the fluid collection chamber 200 (see Figures 6A, 6B, 7A, 7B, 8A, 8B, 9A, 9B and 10). The protrusions of the f Iter plate are preferably achieved by repousse or by pressing, stamping or embossing a depression 131 on the back face 123 to create a protrusion 132 on the front face 121. These stamped through protrusions 132 are preferably present on only one face of the filter plates 120, 160, but may also be present on both faces. Instead of creating the protrusions by metal working, the protrusions may also be adhered to one or both faces of the filter plate and may be sprayed-on, rolled-on, or the like.

[0068] Although in the most basic construction each filter plate can be paired with a completely flat backer plate (not shown) having the core opening 128, such a construction has an overall lower porosity and higher cost, due to the space occupied by and the cost associated with the backer plates. Preferably, the filter unit includes stacked filter plates only, with each subsequent filter plate in the stack functioning as the backer plate for the preceding filter plate. The porosity of the stack of filter plates 120, 120' can be selected by adjusting the height of the protrusions 132. To increase the porosity of the filter unit, the filter unit preferably includes multiple pairs of f Iter plates (120,120') arranged behind the cover plate 230 in a stack of alternating filter plates 120 and 120', whereby each filter plate 120' sandwiched between two filter plates 120 functions as the backer plate for one filter plate 120 and as the cover plate for the other filter plate 120. By alternating the filter plates (120, 120 ), the separating pressure capacity of the filter unit 300 is significantly increased over constructions using alternating filter plates and flat backer plates.

[0069] It will be readily understood that the simple stacking of identical filter plates 120 with protrusions 132, which are logically associated with depressions on the opposite face of the filter plate, will not result in the creation of a filter passage between the filter plates, since the protrusions will nest in the depressions. Thus, every second filter plate 120' in the stack must somehow be different in orientation or construction to avoid nesting. This can be achieved by manufacturing two types of filter plates with respectively different protrusion patterns. However, manufacturing multiple types of filter plates increases the manufacturing cost as well as the assembly cost. Thus, it would be preferable to use only one single type of filter plate.

[0070] In in order to avoid nesting of the plates, nesting of the protrusions must be prevented. This is either achieved through specific placement of the protrusions, or through specific shaping of the protrusions, as will be discussed in more detail in the following.

[0071] Multiple possibilities for stacking without nesting exist. Flipping every second filter plate upside down prior to stacking will result in filter plate pairings in which the protrusions of one plate engage protrusions of the other plate, if the protrusions are arranged symmetrically in relation to a central mirror axis of the plate. Thus, the filter gap width in those filter plate stacks will be twice the height of the protrusions. Of course, the flipping axis will have to be the same as an axis of symmetry of the core opening. If the protrusions are arranged on the filter plate to be staggered in the direction of reflection symmetry, the protrusions of the flipped over plate will not come into engagement with those of the first plate and the filter gap width will be equal to the height of the protrusions. Figure 6B shows a filter plate 120 with a number of identical protrusions 132 which are arranged in a pattern that will prevent nesting when the filter plate 20 is flipped along one of the axes of symmetry 125 of the core opening 128, creating a flipped over filter plate 160 (Figure 7B). Thus, the protrusions are placed in a reflection asymmetrical pattern of protrusions 132 and flats 1 3, in which a first location 400 including a protrusion is always associated with a reflection symmetrical, second location 420 including a flat, or a second location 420 including a flat is always associated with a reflection symmetrical, first location 400 including a protrusion. Thus, in the asymmetrical pattern each protrusion is at a f rst location is paired with a flat at a reflection symmetrical second location. This is apparent from Figure 6A wherein each protrusion 132 is associated with a flat 33 at a re ection symmetrical location. One pair of reflection symmetrical first and second locations 400 and 420 and their respectively associated protrusion and flat are shown in Figure 6A along line 127.

[0072] Another possibility for stacking without nesting consists in rotating every second filter plate 120 (Figure 6A) by 180 degrees in the plane of the plate to generate a rotated filter plate 120' (Figure 6B), after providing the filter plate 120 with a rotation asymmetrical pattern of protrusions 132 and flats 133. In that pattern, each first location 400 including a protrusion 132 is always associated with a rotation symmetrical second location 420 includ ing a flat 133. This is apparent from Figures 6A and 6B where each protrusion 132 is associated with a flat 133 at a rotation symmetrical location. One pair of rotation symmetrical first and second locations 400 and 420 and their respectively associated protrusion 132 and fat 133 are shown in Figure 6B along line 127a .

[0073] Of course, the flipped filter plate 160 (Figure 7B) can also be stacked with a flipped and rotated filter plate 160' (Figure 7A) without nesting, if the protrusions on the original filter plate 120 are placed in a reflection and rotation asymmetrical pattern of protrusions 132 and flats 133, in which a first location 400 including a protrusion is always associated with a reflection and rotation symmetrical, third location 430 including a flat, or a third location 430 including a flat is always associated with a refection and rotation symmetrical, first location 400 including a protrusion. Thus, in the rotation and reflection asymmetrical pattern each protrusion at a first location is paired with a flat at a refection and rotation symmetrical third location. This is apparent from Figure 6A wherein each protrusion 132 is associated with a flat 133 at a reflection and rotation symmetrical location. For ease of understanding one example of such a pairing of a protrusion 132 at location 400 with a fat 133 at the rotation and reflection symmetrical location 430 is shown in Figure 6A.

[0074] In yet another possibility, nesting is avoided by producing the protrusions with a rotation asymmetrical or reflection asymmetrical shape as illustrated in Figures 8A, 8B, 9A and 9B, which again show a single type of filter plate 190 (Figure 8A), which can be rotated by 180 degrees to avoid nesting and generate filter plate 190' (Figure 8B), flipped to avoid nesting and generate filter plate 195 (Figure 9A), or flipped and rotated to avoid nesting and generate filter plate 195' (Figure 9B). As is apparent, the protrusions are individually oriented and shaped such their flipped or rotated shapes are non- congruent, which means each protrusion at a first location 400 is paired with a non- congruent protrusion at the reflection symmetrical location 420 and a non-congruent protrusion at the rotation symmetrical location 430. [0075] In the embodiment of Figure 2, the separation module 100 is mounted to the barrel 500 of a screw press and the core opening 128 is sized to fittingly receive a portion of the extruder screw 150 (see Figure 10). The extruder screw of a screw press generally has very close tolerances to the core opening 128 of the filter block 300 and continually scrapes the compressed material away from the filter surface while at the same time generating significant separating pressures. In the event that a small amount of fibers become trapped on the surface of the filter, they will be sheared by the extruder screws into smaller pieces and ultimately pass through the filter and out with the liquid stream as very fine particles. This provides a solid/fluid separatron device which allows for the separation of solid and liquid portions of a material in a high pressure and high temperature environment.

[0076] By having the extruder screw 150 tangentially swipe the filter gap 134 between the filter plates 120, 120' (see Figure 10) the separation device is less susceptible to clogging. Due to the elevated porosity and pressure resistance of the separation module 100 in accordance with the present disclosure, a dry matter content in the dry portion discharge of up to 90% is possible, while at the same time a relatively clean liquid portion is achieved, due to the small pore size, with suspended solids being as low as 1%. It will be readily understood that the solid/fluid separation module in accordance with the present disclosure can be used in many different applications to separate solid/fluid portions of a material.

[0077] In pilot testing on a continuous basis, aliquots of 100g biomass containing

40g of solids and 60g of water were washed with 40g of water and then the liquid was squeezed out in the separation module using 600 psig internal force at a temperature of 100C to obtain a dry biomass discharge (solids portion of the liquid/solid biomass) containing 39g of suspended solids and 5g of water. The filtrate containing 95g of water was relatively clean containing only Ig of suspended solids with a mean particle size of 5 microns and a particle distribution as per Figure 11.

[0078] Further, as the solid/fluid separation device of the present disclosure is less susceptible to clogging, there is less need for maintenance as is periodically required with known separation devices. Thus, the solid/fluid separation device can be used in a process with less downtime and less maintenance resulting in increased production capability and less cost.

[0079] Figures 6A, and 8A, show alternate designs of a preferred filter plate of the present disclosure. Filter plate 120 of Figure 6A and filter plate 160 of Figure 8a are of the same basic construction. Filter plates 120,160 include a circular middle section 122 attached to a first support tab 124 and a second support tab 126. The circular middle section 122 has a figure eight shaped core opening 128 for fittingly receiving the press screws of a twin screw press. Of course, the core opening 128 will be of different shape for use with screw presses including a different number of press screws. The filter plates 120, 160 have a front face 121 and a back face 123. The core opening 128 is surrounded by a plurality of protrusions 132 on the front face 121 , which are associated with depressions 131 on the rear face 123. To achieve maximum solid/f uid separation efficiency, it is desirable to minimize filter pore size, while maximizing filter porosity. Minimizing pore size is a challenge in conventional screw presses due to the need for cutting cylindrical passages into the filter jacket, or cutting radial slots into filter plates. This problem is addressed with a filter unit in accordance with the present disclosure, wherein filter pores are formed by simply providing protrusions 132 on a thin filter plate 120, 160. The protrusions 132 are preferably stamped through protrusions projecting from the front surface of the f Iter plate. Very small f Iter pores can be achieved with filter plates 120 in accordance with the present disclosure, since stamped protrusions can be produced which have a height smaller than the thickness of the plate. Thus, the plate thickness is no longer the limiting factor in minimizing the filter slot size. For example, by using a filter plate of 0.005 inch thickness and protrusions of 0.002 inch height, a f Iter gap is achieved which is only 40% of the thickness of the f Iter plate. For even finer filtering, protrusions as small as 0.0001 inch height can be produced by pricking of a filter plate of 0.005 inch thickness, thereby achieving a f Iter gap size of 0.0001 inch, allowing the filtering of all particles above 0.0001 inch in diameter. Protrusions produced by pricking are not stamped through protrusions, since the pricking process produces small surface protrusions on the surface to which the embossing-pricking is applied.

[0080] The f Iter plate mounting tabs 124, 126 are all shaped to be fittingly received between pairs of alignment ridges 223 mounted on an inner wall of the pressure jacket 220. Figure 10 illustrates one basic filter pack in accordance with the present disclosure, including alternating filter plates 120 and rotated filter plates 120'. Fluid (liquid and/or gas) entrained in the pressurized mass (not illustrated) fed through the core opening 128 is forced by the separating pressure to flow into the filter gaps 134. At the end 136 of the filter gap 134, the fluid enters into the collection chamber (see Figure 10). As such, the fine filter plate 120 can filter out liquid and very small particles which travel through the f Iter gaps 34 in a direction transverse to the flow of biomass through the figure eight shaped core opening 128. [0081] Overall, with the higher pressure capability, either more liquid can be squeezed from the solids or, for the same material dryness, a higher production rate can be achieved per unit filtration area. The quality of filtration (solids capture) can be controlled depending on plate configurations and thicknesses. The filtration / pressure rating /capital cost can be optimized depending on the f Itration requirements of the particular biomass. The plate configurations can be installed in an extruder {single, twin or triple screws) to develop high pressure, high throughput, continuous separation. The solid/fluid separation module is self-cleaning {for twin and triple screws) due to the wiping nature of the screws and the cross axial flow pattern. The filtration area is flexible depending on process requirements as the length of plate pack can be easily custom fit for the particular requirements. The module can be used to wash solids in a co current or counter current configuration in single or multiple stages in one machine reducing capital cost and energy requirements. The pressure of the liquid filtrate can be controlled from vacuum conditions to even higher than the filter block internal pressure (2,000 to 3,000 psig) if required. This provides great process flexibility for further separations in the liquid stream (example super critical C02 under high pressure, ammonia liquid used for washing under high pressure, or release of VOC and ammonia gases in the liquid filtrate chamber using vacuum). The high back pressure capability (higher than internal filter block pressure) can be used to back flush the filter during operation in case of plugging or scaling of the f Iter, thereby minimizing down time.

Fine Filter Porosity

[0082] The size of the particles to be separated or filtered determines the size of the filter gap is the height of the protrusions 132, which in turn define the width of the filter slot at the core opening. In the filter plate of Figures 6A, 6B, 7A, 7B, the height of the protrusions can be as small as 0.0001 inch and the filter plate thickness can be as low as 0.005 inch, making the filter gap 0.0001 inch in width and the filter porosity 2%.

Coarse Filter Porosity

[0083] In an experimental coarse filter plate used, as shown in Figures 6A, 6B,

7A, 7B, in terms of filtering capability and liquid flow path, the width of the f Iter slots was more than the thickness of the f Iter plates, resulting in a large pore size. The height of the protrusions was 0.05", while the f Iter plate thickness was 0.005 ¹ ', resulting in a filter gap of 0.05 inch and a porosity of 91 %.

[0084] With the filter plates of the present disclosure, filter porosity can be controlled by varying one or both of the protrusion height and the filter plate thickness. Reducing the filter plate thickness by 50% will double the porosity of the filter unit.

Meanwhile, the strength of the filter unit will decrease whenever the filter plate thickness is decreased, but this can be counteracted by increasing the overall diameter of the plates, making the liquid flow path slightly longer but keeping the open area the same.

[0085] The use of only one type of filter plate 120 for the manufacturing of the filter module allows for low cost production of the f Iter. By using the simple stamping operation for production of the protrusions, production costs are lowered even further, especially if a single embossing die is used and the protrusion height is controlled simply by the stamping pressure applied. The overall equipment cost for biomass pretreatment is also lower due to the capability of having multiple process steps occurring in a single machine. The solid/fluid separation module can accommodate three-phase separation simultaneously.

[0086] The type of material used for the manufacture of the filter unit can be adapted to different process conditions. For example, in low pH/corrosive applications materials like titanium, high nickel and molybdenum alloys can be used.

[0087] It is contemplated that the solid/fluid separation device can be used in many different applications to separate solid fluid portions of a material. Further, as the solid/fluid separation device of the present disclosure is less susceptible to clogging, there is less need for maintenance including back washing as is periodically required with known devices. Thus, the solid/fluid separation device can be used in a process with less downtime and less maintenance resulting in increased production capability and less cost.

[0088] In the solid/fluid separation device described, the screw elements that transfer the material internally in the separation device preferably have very close tolerances to the internal surface of the filter block and continually scrape the material away from the filter surface. In the event that a small amount of f bers became trapped on the surface of the filter, they will then be sheared by the closely spaced extruder elements into smaller pieces and ultimately pass through the filter and out with the liquid stream.

[0089]The following examples set forth a series of separation runs for the separation of several different types of solid/liquid mixture, slurries, etc., using the improved twin screw extruder separating apparatus of the present disclosure. It is to be understood, however, that these examples are provided by way of illustration and nothing therein should be taken as a limitation upon the overall scope of the invention. Example I

Biofuel Process

[0090] As shown in Figure 1 , a simple continuous cellulosic ethanol re-treatment system 2 of the present disclosure consists of only three machines. A first extruder 4, a vertical reactor 6 and a second extruder 8. The first extruder 4 is used as a continuous high pressure plug feeder/mixer for biomass. The extruder 4 feeds the biomass into the vertical reactor 6. The vertical reactor 6 is capable of having a long residence time. The vertical reactor 6 feeds the biomass into the second extruder 8, preferably a twin screw extruder. In the pre-treatment process, the biomass flows in sequence through the first extruder 4, the vertical reactor 6, and the second extruder 8.

[0091] The extruder 4, which may also be a twin screw extruder, is used to provide a continuous feed into the pressurized vertical reactor 6. Mixing of various chemicals in the extruder 4 is possible depending on the type of feedstock. The extruder 4 has an automatic valve, which closes upon loss of feed to prevent loss of pressure in the reactor in the case of loss of feedstock.

[0092] Vertical Reactor 6 is capable of operating with various chemicals at pressures of up to 350 psig and temperatures of up to 425 oF (220 oC) depending on the biomass. Residence time in the vertical reactor 6 can be varied from a few minutes to many hours depending on the biomass.

[0093] The partially treated biomass is discharged from the vertical reactor 6 into the second extruder 8 at a pressurized feed zone 10. In the second extruder 8, most of the solid biomass moves to an output end (right side in Figure 1 ), and a small fraction is conveyed backward to create a pressure seal on the drive shafts. In the second extruder 8, higher pressures are generated than in the f rst reactor, as required by various biomasses and the pre-treatment process is completed by two, three or more separate processes depending on the biomass.

[0094] Wash liquid (water, ammonia or other) moves counter or co-current to the flow of solids biomass (to the left in Figure 1 ) such that the biomass is washed with the cleanest liquid at the end of the extruder. Gases or super critical fluids such as carbon dioxide can be injected at the output end to improve explosive force as required depending on the biomass treated. At the output end various extruder screws, and /or another reactor vessel, and/or a control valve and/or a rotating orifice can be used to create a dynamic seal and explosive force required by different types of biomass at different pressures and dry matter content. Upon explosive expansion of the biomass from one of these devices at the output, a cyclone or other separating device is used to collect both the solids and any gases, which are ejected.

[0095] Upon entering the second extruder 8, most of the biomass is conveyed forward while a small amount is conveyed backward to create a dynamic pressure seal to prevent leakage from the vertical reactor 6. The biomass enters process stage 1 , as shown on Figure 1 , and is subjected to a higher pressure, high temperature initial counter current filtration zone using a first solid/fluid separation device 12 as will be described in more detail below with reference to Figures 2 to 15. At this point, some biomass only requires squeezing of extractives and hemicellulose syrup and may not require wash water. In the solid fluid separation device, liquid hemicellulose syrup and or extractives are removed with controlled cake thickness by the use of various screw elements.

Permeability, pore size, filter area and pressure rating is controlled by using different filter plate designs, depending on the biomass type treated. Liquid pressure and flashing are controlled by the use of a pressure controlled flash tank 16.

[0096] Upon exiting the first solid fluid separation device 12, the biomass is conveyed forward (to the right in Figure 1 ) and heated with the use of steam / high pressure water from the forward area and pressure through compression / conveying with various screw elements is applied. In process stage 2 shown in Figure 1 , the biomass is subjected to high pressure mixing / kneading with variable shear energy for various biomasses to improve p re-treatment. High pressure, high temperature f nal counter current filtration (can only squeeze partial hemicellulose syrup and extractives and not counter current wash as required by some types of biomass) of liquid hemicellulose occurs with controlled cake thickness by the use of various screw elements.

Permeability, pore size, filter area and pressure rating are controlled by selecting filter plates of appropriate design in a second solid/fluid separating device 14 depending on the biomass type treated. Liquid pressure and flashing is controlled by the use of a pressure controlled flash tank 16.

[0097] In process stage 3, the biomass is subjected to heat and pressure through compression/conveying with various different extruder screw elements. Shear energy is imparted to the biomass to improve enzyme accessibility as required to improve the pre- treatment of various biomasses. High pressure mixing / kneading of biomass with variable shear energy for various biomasses is used to improve pre-treatment. High pressure, high temperature mid-cycle (or final cycle, depending on biomass) can be imparted using counter or co-current filtration of liquid hemicellulose syrup with controlled cake thickness by the use of various screw elements. Permeability, pore size, filter area and pressure rating are controlled by selecting appropriate filter plates in a third solid/fluid separator 8 to suit biomass properties. Liquid pressure and flashing are controlled by the use of t e pressure controlled flash tank 16.

[0098] In process stage 4 shown in Figure 1 , the biomass is subjected to heat and pressure through compression / conveying with various extruder screw elements. High pressure mixing / kneading of biomass with variable shear energy is selectable for various biomasses. In process stage 4, the biomass is mixed with high pressure water or other fluids/soljtions for the final washing stage. Other fluids can include molecules, which are a gas at room temperature such as high pressure liquid C02, which will become super critical within the extruder due to higher temperature or ammonia which will be a high pressure gas.

[0099] The solid fibrous biomass is then conveyed under the highest pressure of the system through the second extruder 8 and one of the dynamic seal alternatives and exits under a controlled explosive decompression of compressed gases such as steam, ammonia or super critical fluids within the f bers at the outlet of the twin screw extruder into a solid / gas separating device (cyclone or other). When high pressure liquid C02 is used, the super critical nature of this fluid when it gets heated by the biomass permeates the internals of the solid fibers similar to a gas and results in a partial flow of the fluid upstream against the solids pressure profile just as a gas does. This super critical fluid within the f ber exerts an explosive force from within most fibers many times greater than a standard gas upon exiting the extruder through the dynamic seal, modifying the solid cellulose particles and thereby increasing enzymatic accessibility. Also at the discharge of the twin screw is an automatic control valve, which is used to keep the system somewhat pressurized should there be a loss of feed or power.

Example I

Extruder Setup for testing

[00100] An exemplary extruder setup was used to establish that the same principle setup of a separation device in accordance with the present disclosure and including a twin screw extruder in combination with a filter module can be used to process not only lignocellulosic biomass, but multiple other feedstocks. Those other feedstocks have very different consistencies than lignocellulosic biomass and in the past have been processed using very different separation devices and setups. The successful use of a single exemplary twin screw extruder device in accordance with the present disclosure for such diverse feedstocks illustrates the broad utility of the separation device concept of the present disclosure. The exemplary extruder had the basic twin screw extruder setup discussed further above. The extruder included an identical pair of cylindrical extruder screws of 25mm diameter x 1143mm screw length (overall length 1290mm), purchased from Harden Industries Ltd. (Guangzhou, China) and a barrel composed of 11 blocks, of which 7 were identical, solid barrel modules and 2 were filter modules, the construction of which will be detailed below. Filter module 1 was located in block 4&5 and filter module 2 was located in block 8&9. That means the barrel was 1 1 blocks long, with each block being 4" in length, and the f Iter modules each covered the length of 2 barrel blocks.

[00101] The extruder was driven by a 7.5HP, 3-phase electric motor (Model 575 TEFC; totally enclosed fan cooled), purchased from Electrozad, (Chatham, Ontario, Canada) at a rotation speed of 40 rpm, which was about 5% of maximum speed. Each filter block included 856 filter plates (428 plates 120 and 428 plates 120 ). The filter plate thickness was 0.005". Each filter plate included multiple protrusions at a height of 0.002", resulting in a total open width at the core of 0.007" per plate and a porosity of 29%. The overall length of the stack of 856 plates was 6" and the overall length of the filter block housing surrounding the stack of plates 8". Backpressure at filter modules I and 2 was controlled by the fit of the extruder screws with barrel blocks 5 and 9 respectively.

[00102]Prior to processing different feedstocks in the extruder, the exemplary extruder was operated by feeding only water, in order to establish a base value for the load on the electric motor required to run the extruder in a no-load condition.

Example II

Feedstock Soybeans

[00103] Soybeans were sourced locally (grown in Chatham-Kent, Southern Ontario, Canada). Content analysis of the soybeans showed the feedstock was composed of 70.7%/wt solids and 29.3% wt liquids, in the form of 13.8% wt oil and

15.5 /wt water. The soybeans were fed whole into the extruder without pre-processing. The total amount of soybeans fed into the extruder was 1.384 kg whole soybean and the total operating time of the extruder was one hour. During extrusion of the soybeans, the motor load was 8 times higher than the baseline established with water. The feed rate, solids output rate and filtrate output rate over time are graphically illustrated in Figure 16. As is apparent from the graph, the f Itrate output is constant over the whole hour of operation, thereby indicating zero degree of clogging of the filter block. The overall output of the extruder was 1 1.5%/wt filtrate, with 5:95% wt equal recovery through each of filter block #1 and #2, thereby indicating that the filtration rate of each filter block is independent of the relative solids content of the feedstock and that the overall filtration rate of the extruder is directly proportional to the number of filter blocks used. This also indicates that the overall filtration rate of the extruder could easily be increased by replacing more barrel blocks with filter blocks. The overall solids discharge was 88.5%/wt. The filtrate was composed of 55.1 % oil, 0.4% suspended solids and 44.5% water, by weight and the solids discharge was composed of 8.4% oil, 79.9% solids and 11.7% water, by weight. This means 46.0% of the incoming oil in the olive oil feedstock was recovered in the filtrate, which translates into a yield of 6.3% soybean oil (w/w) from incoming soybean as-fed, or one liter of soybean oil per 14.5 kg of incoming soybean feedstock.

Example III

Feedstock Sugar Beets

[00104] Sugar Beets were sourced locally (grown in Chatham-Kent, Southern Ontario, Canada). Whole sugar beets were received directly off the field after harvest and stored at an outdoor holding depot. Prior to processing, sugar beets required washing to remove debris (dirt, stones, etc). A hand hatchet was used to split the sugar beets, then these sugar beet slices fed into a food processor using a first pass with the grating blades, followed by a second pass with the cutting blades. This produced a particle size of ~ 5mmx5mm biomass, which was suitable to be fed into the extruder. Content analysis of the sugar beets showed the feedstock was composed of 16.9%/wt sucrose, I 4%/wt other soluble solids, I 3% wt insoluble solids, and 80.4%/wt water. The total amount of sugar beets fed into the extruder was 3.219 kg chopped sugar beets and the total operating time of the extruder was one hour. During extrusion of the sugar beets, the motor load was 25% higher than the baseline established with water. The feed rate, solids output rate and filtrate output rate over time are graphically illustrated in Figure 15. As is apparent from the graph, the f Itrate output is constant over the whole hour of operation, thereby indicating zero degree of clogging of the filter block. The overall output of the extruder was 66.2%/wt filtrate, with 40:60 recovery through f Iter modules #1 and #2, thereby indicating that the filtration rate is pressure dependent, but independent of the relative solids content of the feedstock and that the overall filtration rate of the extruder is directly proportional to the number of filter blocks and the separation pressure used. This also indicates that the overall filtration rate of the extruder could be increased by replacing more barrel blocks with filter blocks and/or by increasing the operating speed of the extruder to increase pressure. The overall solids discharge was 33.8%/wt. The filtrate was composed of 14.1% sucrose, 0.8% other soluble solids, 2.6% of suspended solids and 82.5% water, by weight and the solids discharge was composed of 22.4% sucrose, 2.4% other soluble solids, 1.7% of insoluble solids and 73.5% water, by weight. This means 55.2% of the incoming sucrose was recovered in the filtrate, which translates Into a yield of 9.3% sucrose (w/w) from incoming sugar beet feedstock, or one kilogram of sucrose per 0.7 kg of incoming sugar beet feedstock.

Example IV

Feedstock Olives

[00105] Whole raw black olives were sourced from a distributor within the United States; not packed in water or oil. The olives received were pitted and pre-sliced. These pre-sliced olives were pre-processed further using a food processor to generate a

~5mmx5mm particle size. Content analysis of the resulting olives feedstock showed the feedstock was composed of 19.4% solids and 80.6%/wt liquids, dividing into 27.7% wt oil and 52.9%/wt water. The total amount of feedstock fed into the extruder was .458 kg chopped olives and the total operating time of the extruder was one hour. During extrusion of the sugar beets, the motor load was similar to the baseline established with water. The feed rate, solids output rate and filtrate output rate over time are graphically illustrated in Figure 4. As is apparent from the graph, the filtrate output is constant over the whole hour of operation, thereby indicating zero degree of clogging of the filter modules. The overall output of the extruder was 32.3% filtrate, with 20:80 recovery through filter modules #1 and #2, thereby indicating that the filtration rate is strongly pressure dependent, but independent of the relative solids content of the feedstock and that the overall filtration rate of the extruder is directly proportional to the number of filter modules and the separation pressure used. This also indicates that the overall filtration rate of the extruder could be increased by replacing more barrel blocks with filter modules and/or by increasing the operating speed of the extruder to increase pressure. The overall solids discharge was 67.7%/wt. The filtrate was composed of 50.9% oil, 4.1 % suspended solids and 45% water, by weight and the solids discharge was composed of 16.6% oil, 26.7% solids and 56.6% water, by weight. This means 59.4% of incoming oil was recovered in the filtrate, which translates into a yield of 16.4% olive oil (w/w) from incoming olives feedstock, or one liter of olive oil per 5.5 kg of incoming olives feedstock. As mentioned above, increasing the yield can be achieved by adding filter modules, or increasing the operating pressure, but it is also possible to increase oil recovery from the feedstock by using solvents, for example hexane, the raise the level of oil recovery, which solvent can be admixed to the feedstock prior to feeding it into the extruder, or by injecting the solvent directly into the extruder during operation. Example V

Feedstock Corn cobs pre-hydrolysate

[00106] Corn cobs pre-hydrolysate was obtained by the process described in Example I Content analysis of the feedstock showed the pre-hydrolysate was composed of 4.8% wt hemicellulose, 6.8%/wt cellulose, 5.4% wt other solids and 83%/wt water. The total amount of feedstock fed into the extruder was 7.025 kg and the total operating time of the extruder was one hour. During extrusion of the pre-hydrolysate, the motor load was 40% higher than the baseline established with water. The feed rate, solids output rate and filtrate output rate over time are graphically illustrated in Figure 17. As is apparent from the graph, ttie filtrate output is constant over the whole hour of operation, thereby indicating zero degree of clogging of the filter modules. The overall output of the extruder was 8.0% filtrate, with 99:1 recovery through filter modules #1 and #2, thereby indicating that the filtration rate is strongly pressure dependent and possibly dependent on the relative solids content of the feedstock. It is expected that the filtrate recovery would be much higher at higher extruder pressures (higher rotating speed or different screw configuration). However, it is clear from the constant filtrate flow over the whole hour of operation, that the filter modules did not get clogged by the feedstock. This also indicates that the overall filtration rate of the extruder could be increased by replacing more barrel blocks with filter modules and/or by increasing the operating speed of the extruder to increase pressure. The overall solids discharge was 92%/wt. The filtrate was composed of 4.8% hemicellulose, 0.5% suspended solids (60:40 cellulose:other solids) and 94.4% water, by weight, and the solids discharge was composed of 4.7% hemicellulose, 13.3% solids (56:54 cellulose other solids) and 82% water, by weight. This means 8.7% of incoming hemicellulose was recovered in the f Itrate, which translates into a yield of one kilogram of hemicellulose sugars per 44.6 kg of incoming corncobs pre-hydrolysate feedstock. As mentioned above, increasing the yield can be achieved by adding filter modules, or increasing the operating pressure.

Further Applications/Feedstocks

[00107] The dewatering of pulp & paper slurries. Food slurries, fruit pulp (cider production) is presently limited and it is expected that the twin screw extruder separation apparatus of the present disclosure will allow dewatering of these feedstocks to a level of 50 to 60% dry matter (DM) with cost effective energy usage, the twin screw extruder separation apparatus of the present disclosure is also expected to allow the formation of bioenergy pellets from wet waste solids without the need for additional drying as it is expected to produce dry solids over 80% which then can go straight to peptization and minor final drying producing bioenergy pellets with very low energy.

[00108] In view of the currently observed versatility of the twin screw extruder separation apparatus of the present invention, it is expected that the apparatus will also be applicable for the dewatering of various mining tailings which are thrxotropic. It is expected that water can squeezed out of these slurries with the apparatus of the present disclosure before entering the tailings ponds, due to the ability to form filter gaps as small as 0.0001 inch. This would be environmentally advantageous and would save great amounts of storage capacity. An example of this would be the Solvay synthetic soda ash process tailings.

[00109] In view of the successful processing of soybeans and other feedstocks as discussed above, it is expected that the twin screw extruder separation apparatus of the present disclosure will also be applicable for the plant oil extraction from hemp, corn and many types of nuts and seeds through squeezing and pressing, with or without solvents.

[001 10] In view of the successful processing of various feedstocks as discussed above, it is expected that the twin screw extruder separation apparatus of the present disclosure will also be applicable for the additional dewatering in a variety of food processing applications, such as tomato paste, tomato ketchup, potato starch processing, juices, and other pastes or jams.

[001 11] Although this disclosure has described and illustrated certain

embodiments, it is also to be understood that the system, apparatus and method described is not restricted to these particular embodiments. Rather, it is understood that all embodiments, which are functional or mechanical equivalents of the specific embodiments and features that have been described and illustrated herein are included.

[001 12] It will be understood that, although various features have been described with respect to one or another of the embodiments, the various features and

embodiments may be combined or used in conjunction with other features and embodiments as described and illustrated herein.