US20220018066A1

US20220018066A1 - Biomass Processing

Info

Publication number: US20220018066A1
Application number: US17/379,758
Authority: US
Inventors: Richard Blair
Original assignee: Earth's Renewable Energy LLC
Current assignee: Earth's Renewable Energy LLC
Priority date: 2020-07-17
Filing date: 2021-07-19
Publication date: 2022-01-20
Also published as: WO2022016159A1; WO2022016159A9

Abstract

Processing systems and methods are described for pre-processing processing of biomass. The systems include an extruder characterized by one or more ports though which acids and/or bases may be introduced to the biomass during extrusion. The acids may be selected to hydrolyze the biomass and the base may be selected to neutralize the acid. Neutralization can occur using a solid base within the extruder.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority and benefit to U.S. provisional patent application Ser. No. 63/053,099 filed Jul. 17, 2021. The disclosure of which is hereby incorporated herein by reference.

BACKGROUND

Field of the invention

The invention is in the field of biomass processing.

Related Art

Mixed biomass present in residential and agricultural waste presents a processing challenge in that the mechanical properties of the bulk material can vary widely. In order to realize value added products from this material it is preferably pre-processed into a uniform material suitable for chemical attack. Optimal depolymerization of cellulose and hemicellulose to their respective monomers occurs when the feedstock has a small particle size a low degree of crystallinity.
Conversion of lignocellulosic biomass to value-added products at an industrial scale requires an initial size reduction step (preprocessing). Two technologies are typically used for this step: cutting mills and hammer mills. Cutting mills work well for fibrous and soft materials, but not so well for hard materials such as grains. Hammer mills optimally process these hard materials. Both of these technologies may be optimized for size reduction. Although size reduction is needed for further processing, extended pre-processing times will reduce plant profitability and therefore should be kept short. Size reduction power requirements can vary from 4-400 kWh/MT. The most common form of biomass structure disruption is steam explosion where the feedstock is subjected to steam under pressures of 1-3 MPa and temperatures of 180-240° C. This is energy intensive.

SUMMARY

Systems and methods of (pre-) processing biomass for size reduction and/or preparation as feedstock for further conversion are presented. These include mechanical and/or chemical processing to break down the bulk structure of biomass. In various embodiments, the systems and methods are configured to optimize size reduction, fiber disruption, and/or amorphization. Ideally, a uniform easily conveyed material is produced using the systems and methods described herein. Such pre-processed biomass can produce consistent ultimate yields of fuels or chemicals produced from biomaterials, e.g., plants. To meet this goal a combined mechanical and chemical approach is used. Specifically, this approach may include simultaneous mechanical processing and the use of acids to break down biomass. Optionally, acids are neutralized using a base within the mechanical processing system.
Natural cellulose is highly crystalline, which severely limits its acid and enzymatic hydrolysis rate. The crystallinity of cellulose can be reduced through mechanical processing and/or chemical methods. Chemical hydrolysis can eventually reduce the crystallinity of the feedstock. However, extended contact with strong acids leads to degradation of lignin in the biomass and lowers the feedstock's value. Acid processing should, thus, preferably occur over a limited time period, and be terminated after this limited time period.
In some embodiments, mechanical processing through steam explosion or mechanical milling is used to sufficiently reduce the crystallinity of the parent material to realize improved hydrolysis rates while at the same time limiting the amount of undesirable by-products. The compressive events in mechanical processing can alternatively be realized in a screw extruder through the use of multi-lobe mixing elements. The shape and location of these elements allow control of amorphitization and hydrolysis rates and subsequently the end products mechanical and chemical properties. Proper application of mixing, hydrolysis, and neutralization can result in a product with a free moisture content below 20% or 10% and a bulk modulus less than 66% or 75% of the unprocessed feedstock. As the biomass material passes between two mixing lobes it experiences high compressive force. It also can be compressed against the barrel of the extruder through the use of tapered screws. Both processes will reduce the crystallinity of the holocellulose present in the feedstock.
In some embodiments, the time during which the biomass is exposed to the acid(s) is controlled by the addition of one or more base such as, for example, slaked lime (Ca(OH)2) or lime (CaCO3). The addition of the base is optionally achieved via a (second) port in the extruder. As such, the addition of acids and/or bases may be performed “in-line” while the biomass is within a flow-through processing system including one or more extruders. In some embodiments the biomass is processed using more than one extruder in series, wherein the output of a first extruder is passed to the input of second extruder. Input ports may be disposed within or between sections of an extruder.
Since the material is flowing through the extruder, the addition of a base can occur downstream from the addition of the acid. The positions at which the acid and base are added and the flow rate within the processing system can be used to control the time during which the biomass is exposed to the acid (acidic conditions). This allows for sufficient time for amorphitization of the biomass while controlling the degradation of lignin by the acid. The addition of the base enhances the disruption of the biomass and neutralizes the acid(s). The (pre-processed) biomass flowing out of the extruder is ready for enzymatic hydrolysis and holocellulose removal. This enhanced approach makes the process feedstock agnostic to the expected variations in the physical properties of the unprocessed biomass, while taking advantage of the relatively high quality achievable using extruder pre-processed biomass. Additionally, a minimum of acid may be consumed and no acidic products may be produced. The output of the flow-through processing system is acid processed but is neutralized before leaving the flow-through processing system. This eliminates the need for tank neutralization and subsequent waste disposal. In some embodiments, carbon dioxide gas is also directed through the screw extruder to suppress oxidation reactions that can occur during preprocessing of biomass and reduce lignin quality. Carbon dioxide is optionally added to the extruder as a gas, liquid, solid or supercritical fluid.
Various embodiments of the invention include a flow-through biomass processing system comprising: a screw extruder configured to convey biomass through the processing system such that processed biomass continuously exits the flow-through biomass processing system, the screw extruder including: a housing, at least a first shaft including a section configured to convey the biomass through the screw extruder and a section configured to compress the biomass, and a first port configured to introduce a base to the biomass within the screw extruder; and a motor configured to rotate at least the first shaft. Optionally, the screw extruder is a multi-screw extruder and includes at least a second shaft, and including a section configured to convey the biomass through the first screw extruder and a section configured to compress the biomass. Optionally, the processing system further comprises a second port configured to introduce an acid to the biomass within the screw extruder, wherein the second port is disposed upstream of the first port, relative to the flow of the biomass through the screw extruder, the acid being configured to neutralize the base.
Various embodiments of the invention include a method of processing biomass, the method comprising: introducing the biomass to a screw extruder, the screw extruder including a first shaft having a section configured to convey the biomass through the screw extruder and optionally having a second shaft configured to compress the biomass but not necessarily convey the biomass through the screw extruder; introducing an acid to the biomass, the acid configured to hydrolyze the biomass; introducing a base to the biomass within the screw extruder, the base being configured to neutralize the acid introduced to the biomass, the acid being neutralized within the screw extruder; receiving a continuous flow output of the screw extruder, the output including the biomass neutralized by the base.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating components of a biomass processing system according to various embodiments of the invention.

FIG. 2 illustrates method of processing biomass, according to various embodiments of the invention.

FIG. 3 illustrates a twin screw extruder, according to various embodiments of the invention.

FIG. 4 illustrates a multi-stage extruder, according to various embodiments of the invention.

FIG. 5 illustrates mixing lobes, according to various embodiments of the invention.

DETAILED DESCRIPTION

The microstructure of biomass is preferably disrupted prior to further chemical and/or enzymatic processing for maximum holocellulose removal. Plant cell walls are composed of crystalline cellulose fibrils, hemicellulose, and lignin. Feedstocks with high cellulose content require further processing to improved holocellulose removal. However, high shear processing can also disrupt the structure of the feedstock. This is approach may be applied in the production of nanocellulose fibers and/or applied to biomass depolymerization. High shear with continuous processing is easily achieved in a co-rotating twin-screw extruder where high shear occurs in modular zones utilizing mixing lobes. In various embodiments, after size reduction, an ideal material will have a particle size less than 10, 5 or 3 mm.
FIG. 1 is a block diagram illustrating components of a biomass Processing System 100 according to various embodiments of the invention. Processing System 100 is a flow-through system including an Extruder 100, a Motor 115, optional Control Logic 120, and/or optional (one or more) Sensors 125. As used herein, a “flow-through” system is one in which the material being processed is continuously feed into the system and processed material continuously exits the system. A flow-through system can be contrasted with a “batch” system in which material is processed in discrete batches.
Extruder 110 is a screw extruder configured to convey biomass through the processing system such that processed biomass continuously exits Processing System 100. Extruder 110 may be a single screw or multi-screw (e.g., dual) extruder. Extruder 100 includes a Housing 130 configured to contain the biomass within Extruder 110. Housing 130 is typically a hard material such as carbon steal, a steel-iron-nick alloy, stainless steel, tungsten carbide, titanium, Inconel, chromium, and/or other metal. Housing 110 is hollow, being configured to hold the biomass and one or two Shafts 135. (Two Shafts 135 for a dual-screw extruder, etc.) Shafts 135 are typically made of hard materials such as those discussed herein regarding Housing 130. Shafts 135 operate by rotation within Housing 130 and are rotated using Motor 115.
Shafts 135 optionally include multiple sections (e.g., 1, 2, 3, 4 or more) configured to serve different functions. For example, some sections may be configured to convey (e.g., drive, move or propel) the biomass through Extruder 110, while other sections may be configured to apply compressive forces to and mix the biomass. An exemplary embodiment includes two “convey” sections with a third “compression” section disposed between them. Compression sections may also be referred to herein as “mixing” sections. Other embodiments may include: one convey section and one compression section, three convey sections interspaced by 2 compression sections, and/or additional sections. In some embodiments a section is configured to both convey and compress/mix the biomass. Examples of sections that may be included in Shafts 135 are discussed elsewhere herein. FIG. 1 illustrates a First Section 140 and a Second Section 145, including Shafts 145. First Section 140 may be upstream from Second Section 145. First Section 140 may be a convey section while Second Section 145 may be a compression section. An optional third section may be configured to further convey the biomass through Extruder 110.
Extruder 110 further includes a First Port 150 and/or a Second Port 160. First Port 150 being disposed closer to an input of Extruder 110 relative to Second Port 160, the input being where biomass is introduced into Extruder 110. First Port 150 and Second Port 160 are configured for introducing reagents from the exterior of Housing 130 to the biomass within Extruder 110. First Port 150 and/or Second Port 160 may be configured for introducing (to the biomass) liquids, solids, lubricants, surfactant, steam, acids, bases, enzymes, oils, oxidizers, supercritical fluids, and/or the like. For example, in some embodiments, First Port 150 is configured for introducing an acid to the biomass. The acid may be configured to promote decomposition of the biomass. Likewise, Second Port 160 may be configured for introducing a base to the biomass, the base typically being configured to neutralize the acid. Second Port 160 is optionally configured to introduce the base as a solid.
In an exemplary embodiment, First Port 150 is disposed near an input to Extruder 110 such that the acid is introduced to the biomass at a point where the acid and biomass will be mixed by the rotation of the Shafts 135. In this embodiment, Second Port 160 may be disposed closer to the output (downstream from the input) of Extruder 110 such that the acid is neutralized after some time of being in contact with the biomass, and after the biomass has been mixed and/or exposed to compression in a compression section of Extruder 110. The Second Port 160 is optionally disposed such that additional mixing occurs before the biomass leaves Extruder 110, giving opportunity for the acid and base neutralization reaction to occur within Extruder 110. Given sufficient base and opportunity for the acid to react with the base, the processed biomass that exits Processing System 100 and/or Extruder 110 may be neutralized using the base. Second Port 160 is optionally configured to add a quantity of base to the biomass sufficient to neutralize the acid. Second Port 160 may be configured to add the base as a liquid and/or solid.
First Port 150 is optional in embodiments in which the acid is added to the biomass prior to introducing the biomass to Extruder 110. Extruder 110 may include more than two input ports. First Port 150 and Second Port 160 are optionally configured to introduce water, CO₂, supercritical water, steam, supercritical CO₂, and/or the like to the biomass.
Motor 115 may be an electric motor, an internal combustion motor, a micro turbine, and/or the like. Motor 115 optionally includes a system (e.g., gearing, reducer and/or transmission) configured to adjust the torque applied by Motor 115 to Shafts 135. Motor 115 and/or the torque adjustment system are optionally controlled by Control Logic 120.
Control Logic 120 is configured to use the output of Sensors 125 to control the operation of Processing System. The “logic” of Control Logic 120 includes: hardware, firmware, and/or software stored on a non-transient computer readable medium. Control Logic 120 may further include a user interface, electrical/signal connections to Sensors 125 and/or Motor 115, electrical/signal connections to First Port 150 and/or Second Port 160, data storage, and/or the like. In some embodiments, Control Logic 120 includes a programmable printed circuit board including electronic circuits configured to perform the functions of Control Logic 120.
Control Logic 120 is optionally responsive to the outputs of one or more Sensors 125 configured to detect characteristics of the biomass or state of Processing System 100. For example, in some embodiments, Control Logic 120 is configured to control Motor 115 so as to adapt the rotational rate or torque of Shafts 125 based on detected characteristics of the biomass. In another example, Control Logic 120 is configured to deduce characteristics of the biomass based on measurement of the speed(s) of Shaft(s) 135, electrical current provided to Motor 115, and/or torque applied by Motor 115 to Shafts 135.
In some embodiments, Control Logic 120 is configured to automatically determine content of the biomass. For example, using Sensors 125, Control Logic 120 may automatically determine a moisture content of the biomass, a structural profile of the biomass (e.g., how many leaves, wood chips or sludge), a temperature of the biomass, a pH of the biomass, an age of the biomass (e.g., green leaves or brown), spectroscopic characteristics of the biomass (e.g., wavelength dependent properties), a gas content of the biomass (e.g., methane content), and/or the like.
Control Logic 120 is optionally configured to determine an amount of acid or base to add to the biomass based on any of the detected characteristics, and to add the determined amount using First Port 150, Second Port 160, and/or some other port (optionally through Housing 130). Such determinations may be made based on any combination of the determined biomass characteristics and/or content discussed herein. Optionally, First Port 150 and Second Port 160 include a dispenser configured to introduce a controlled amount of liquid and/or solid to the biomass. Such dispenser is optionally configured to dispense specific volumes or weights under the control of Control Logic 120. A wide range of suitable dispensers for liquids and/or solids are known in the art of material handling.
In some embodiments, Control Logic 120 is configured to determine an amount of the base to add to the biomass based on an amount of the acid added to the biomass. For example, an amount of acid to add to the biomass may be determined based on the pH, types of materials, and/or moisture included in the biomass, then after making this determination, Control Logic 120 may determine an amount of base to add to the biomass such that the acid is approximately neutralized by the base.
In some embodiments, Control Logic 120 is configured to add a fluid and/or lubricant to the biomass, optionally via First Port 150, Second Port 160, some other port, and/or prior to introducing the biomass to Extruder 110. The lubricant may be liquid or solid, and is optionally selected to be acid resistant. In some examples, a solid lubricant includes water, steam, CO₂, carbon or polymer material that is acid resistant, but that may be decomposed by further processing of the biomass, e.g., during depolymerization of cellulose or hemicellulose. The amount of fluid and/or lubricant to be added to the biomass may be determined by Control Logic 120 based on any of the biomass characteristics and/or content discussed herein. For example, the amount may be based on a detected rotational rate or torque of Shafts 135, a dryness of the biomass, and/or contents of the biomass.
Sensors 125 may include any of a large variety of sensors, including those configured to detect the biomass characteristics and/or components discussed herein. Sensors 125 may consist of one or multiple sensors. Examples of Sensors 125 include, but are not limited to: moisture sensors, pH sensors, temperature sensors, cameras (and associated image processing logic), weight sensors, spectroscopic sensors, weight sensors, acoustic sensors, electrical current sensors, mass sensors, lidar, radar, torque sensors, and/or the like. Camera sensors may be used to detect content, age, size distribution, and/or color of the biomass. These characters may be derived from images using image processing logic.
Sensors 125 may be disposed within any part of Processing System 100. For example, mass and camara sensors may be disposed before the input to Extruder 110, pH and moisture sensors may be disposed proximate to First Section 140, a current sensor or torque may be coupled to Motor 115, and a temperature sensor may be disposed at the output of Extruder 110.
FIG. 2 illustrates methods of processing biomass, according to various embodiments of the invention. These methods are optionally performed using Processing System 100 as discussed elsewhere herein.
In an Introduce Step 210, biomass is introduced into an extruder, such as Extruder 110. This may be accomplished, for example, using a funnel, conveyor, screw feeder, and/or the like. Extruder 110 is optionally disposed horizontally or vertically. The rate (in volume or weight) of biomass introduced is optionally controlled by Control Logic 120.
In an optional Analyze Step 220, characteristics and/or content of the biomass are determined using Sensors 125. Analyze Step 220 can include use of any of the Sensors 125 discussed herein to determine any of the biomass characteristics and/or contents discussed herein. Parts of Analyze Step 200 may be preformed prior to Introduce Step 210 or after a Receive Step 260 (discussed further below), or at any point/time therebetween. For example, moisture and contents may be detected prior to introduction of the biomass to Extruder 110. Temperature may be detected at various positions with Extruder 110, and pH may be detected after the biomass has been extruded from Extruder 110.
In an optional Adapt Step 230, Control Logic 120 is used to adapt the operation of Processing System 100 based on characteristics and/or contents (or other information) determined in Analyze Step 220. Such adaptation can include, for example, changing an amount of biomass introduced into Processing System 100, changing an amount of acid and/or base introduced into Processing System 100, changing operation of Motor 115, changing a temperature of Extruder 110, adding a lubricant to the biomass, and/or the like.
In an Add Acid Step 240, an acid is introduced to the biomass, optionally within Extruder 110 and optionally via First Port 150. The acid is typically configured to hydrolyze the biomass. Add Acid Step 240 may occur prior to any of the preceding steps. An amount of acid introduced is optionally determined using Control Logic 120 as discussed elsewhere herein.
In an optional Add Base Step 250, a based is introduced to the biomass, optionally via Second Port 155. Typically, an amount of base added is approximately sufficient to neutralize the acid introduced in Add Acid Step 240. An amount of base introduced is optionally determined using Control Logic 120 discussed elsewhere herein. The base may be added as a solid or a liquid. The base may be added at a location within Extruder 110 such that mixing and extrusion of the biomass between the introduction of the base and the exit of the Extruder 110 is sufficient to approximately neutralize the acid in Add Acid Step 240, within Extruder 110. Thus, the base and biomass may be mixed in a section of Extruder 110 downstream from Second Port 155. The acid is typically added upstream from a location within Extruder 110 at which the base is added. The amount of base added is optionally determined using Control Logic 120 based on the amount of acid added to the biomass.
In a Receive Step 250, the processed (e.g., hydrolyzed) and optionally neutralized by the base, biomass is received at an output/exit of Extruder 110. The biomass is typically received as a continuous flow output, in contrast to a batch mode. The biomass may then be further processed to obtain desirable materials.
FIG. 3 illustrates a twin screw Extruder 110, according to various embodiments of the invention. Co-rotating twin-screw extruders can be used to efficiently disrupt the fibrous structure of biomass in a continuous process. In this example a twin Shafts 135 are disposed within Housing 130. The Housing 130 includes a First Port 150 and a Second Port 160 configured for introduction of any of the materials (e.g., acid and base) discussed herein. Shafts 135 are driven by a Motor 115.
FIG. 4 illustrates a multi-stage Extruder 110 in cross-section, according to various embodiments of the invention. The illustrated example of Extruder 110 includes three sections, a First Section 140, Second Section 145, and a Third Section 410. Optionally First Section 140 and Third Section 410 are convey sections and Second Section 145 is a compression (mixing) section. Third Section 410 is optionally an embodiment of First Section 140 and/or Second Section 145. FIG. 4 also illustrates an Input 420 disposed upstream from an Output 430. The Housing 130 shown in FIG. 4 includes First Port 150, Second Port 160 and an optional Third Port 440. Third Port 440 is optionally an embodiment of First Port 150 and/or Second Port 155. Alternative embodiments of Extruder 110 may include additional sections and/or ports. Alternative embodiments may include 2, 3, 4 or more conveyance regions (sections) separated by compression/mixing regions.
FIG. 5 illustrates mixing Lobes 510, according to various embodiments of the invention. Such Lobes 510 may be found in compression (e.g., mixing) sections of Extruder 110. Lobes 510 are attached to and rotated by Shafts 135. This rotation produces a high amount of mixing (520) and compression at Compression Regions 530. In the Compression Regions 530 both compressive and shear forces dominate mechanical processing. Brittle materials are easily fragmented under the application of compressive force, while soft materials (e.g., fibrous biomass) are more easily processed by the application of shear force.

EXEMPLARY EMBODIMENTS

At least 1, 2, 3 or 5 mass percent of a dilute acid (or any range between these values) such as hydrochloric, phosphoric, and/or sulfuric acids are used as the “acid” discussed herein. The acid will partially hydrolyze the surface of the fibers and increase its plasticity enabling flow through the extruder. The acid is optionally added to the biomass prior to introduction of the biomass to the extruder. Alternatively, in some embodiments, the acid is added to the extruder though a port in the extruder, e.g., First Port 150.
Various embodiments of Processing System 100 can include any combination of the following: A twin screw co-rotating screw (Shafts 135) extruders with a bore greater than 5 cm and a length greater then 1.5, 2 or 3 meters. The screw possesses at least 2 mixing regions (e.g., embodiments of First Section 140 and Second Section 145) each consisting of a set of mixing Lobes 510 and 3 conveyance regions (e.g., embodiments of First Section 140 and Second Section 145) comprising of intermeshed co-rotating screws. An Exit 430 of the extruder, Exit 430 being unrestricted to facilitate free release of processed biomass material. A reservoir of dilute sulfuric acid (or any other suitable acid) is added to the biomass using a First Port 150, the addition occurring after a first conveyance First Section 140 and before mixing in a mixing Second Section 145. A reservoir of base, to be added via Second Port 155. The base optionally including a solid powder such as: limes stone, slaked lime, or quicklime. The base may be added after a second conveyance section and before an additional mixing/compression section. The length of conveyance regions between mixing lobes 1 and 2 is such to allow biomass to dwell for at least 10, 15 or 20 minutes at a typical Shaft 135 rotation rate. Control Logic 120 configured to adapt the rotational rate or torque of the screw extruder (Shaft 135) based on detected characteristics of the biomass. These characteristics can include hardness, mass, moisture content, color, size distribution, contents, and/or any other characteristic discussed herein. To adapt operation of Processing System 100, Control Logic 120 typically uses outputs of Sensors 125 configured to detect these characteristics in biomass. The control logic may also adjust an amount of acid and/or base added to the biomass while the biomass is in the screw extruder responsive to these characteristics.
Several embodiments are specifically illustrated and/or described herein. However, it will be appreciated that modifications and variations are covered by the above teachings and within the scope of the appended claims without departing from the spirit and intended scope thereof. For example, Processing System 100 may further include heating and cooling systems (active or passive), or a system for moving heat from hot regions to cooler regions of Extruder 110. Such systems may be used to disperse heat generated by acid-base reactions, and/or to heat biomass in First Section 140 or prior to introduction to Extruder 110. Processing System 100 may include an active cooling (refrigeration) device and/or a circulation system configured to move heat between parts of Extruder 110. In alternative embodiments the base is added to the biomass prior to addition of the acid, and the acid functions as the neutralizer. Add Acid Step 240 may occur using Second Port 155, before Add Base Step 250.
The embodiments discussed herein are illustrative of the present invention. As these embodiments of the present invention are described with reference to illustrations, various modifications or adaptations of the methods and or specific structures described may become apparent to those skilled in the art. All such modifications, adaptations, or variations that rely upon the teachings of the present invention, and through which these teachings have advanced the art, are considered to be within the spirit and scope of the present invention. Hence, these descriptions and drawings should not be considered in a limiting sense, as it is understood that the present invention is in no way limited to only the embodiments illustrated.
Computing systems and/or logic referred to herein can comprise an integrated circuit, a microprocessor, a personal computer, a server, a distributed computing system, a communication device, a network device, or the like, and various combinations of the same. A computing system or logic may also comprise volatile and/or non-volatile memory such as random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), magnetic media, optical media, nano-media, a hard drive, a compact disk, a digital versatile disc (DVD), optical circuits, and/or other devices configured for storing analog or digital information, such as in a database. A computer-readable medium, as used herein, expressly excludes paper. Computer-implemented steps of the methods noted herein can comprise a set of instructions stored on a computer-readable medium that when executed cause the computing system to perform the steps. A computing system programmed to perform particular functions pursuant to instructions from program software is a special purpose computing system for performing those particular functions. Data that is manipulated by a special purpose computing system while performing those particular functions is at least electronically saved in buffers of the computing system, physically changing the special purpose computing system from one state to the next with each change to the stored data.
The “logic” discussed herein is explicitly defined to include hardware, firmware or software stored on a non-transient computer readable medium, or any combinations thereof. This logic may be implemented in an electronic and/or digital device (e.g., a circuit) to produce a special purpose computing system. Any of the systems discussed herein optionally include a microprocessor, including electronic and/or optical circuits, configured to execute any combination of the logic discussed herein. The methods discussed herein optionally include execution of the logic by said microprocessor.

Claims

What is claimed is:

1. A flow-through biomass processing system comprising:

a screw extruder configured to convey biomass through the processing system such that processed biomass continuously exits the flow-through biomass processing system, the screw extruder including:

a housing configured to contain the biomass with the screw extruder,

a first shaft,

a first section configured to convey the biomass through the screw extruder using the first shaft,

a second section configured to compress the biomass,

a first port configured to introduce an acid to the biomass, the acid being configured to promote decomposition of the biomass, and

a second port configured to introduce a base to the biomass, the base configured to neutralize the acid, wherein the first port is upstream of the second port.

a motor configured to rotate at least the first shaft.

2. The system of claim 1, wherein the screw extruder is a multi-screw extruder and includes at least a second shaft.

3. The system of claim 1, further comprising a third section configured to convey the biomass through the screw extruder.

4. The system of claim 1, wherein the first port is configured to introduce the acid to the biomass, while the biomass is within the screw extruder.

5. The system of claim 1, wherein the second port is configured to introduce the base to the biomass while the base is in the screw extruder.

6. The system of claim 1, wherein the screw extruder is configured to mix the base and the biomass so as to neutralize the acid within the biomass.

7. The system of claim 1, wherein the screw extruder is configured such that the processed biomass that exits the flow-through biomass processing system is neutralized using the base.

8. The system of claim 1, wherein the second port is configured to add the base as a solid.

9. The system of claim 1, wherein the second port is configured to add a quantity of base to the biomass sufficient to neutralize the acid.

10. The system of claim 1, further comprising a control logic configured to adapt the rotational rate or torque of the screw extruder based on detected characteristics of the biomass, and one or more sensors configured to detect the characteristics of the biomass.

11. The system of claim 1, further comprising a control logic configured to add an amount of the acid to the biomass responsive to a moisture content of the biomass or responsive to spectroscopic analysis of the biomass.

12. The system of claim 1, further comprising a control logic configured to add an amount of acid to the biomass responsive to an automatically determined content of the biomass.

13. The system of claim 1, further comprising a control logic configured to add an amount of the base to the biomass responsive to an amount of the acid added to the biomass.

14. The system of claim 1, further comprising a control logic configured to add a lubricant to the biomass in response to a rotational rate or torque of the screw extended.

15. The system of claim 1, further comprising a control logic configured to add a lubricant to the biomass in response to an automatically determined content of the biomass.

16. A method of processing biomass, the method comprising:

introducing the biomass to a screw extruder;

introducing an acid to the biomass, the acid configured to hydrolyze the biomass;

introducing a base to the biomass within the screw extruder, the base being configured to neutralize the acid introduced to the biomass, the acid being neutralized within the screw extruder;

receiving a continuous flow output of the screw extruder, the output including the biomass neutralized by the base.

17. The method of claim 16, wherein the acid is added to the biomass while the biomass is in the screw extruder, the acid added upstream from a location within the screw extruder at which the base is added.

18. The method of claim 16, further comprising analyzing the biomass using one or more sensors and using control logic to determine an amount of the acid to add to the biomass responsive to an output of the one or more sensors.

19. The method of claim 18, further comprising determining an amount of base to add to the biomass responsive to the amount of the acid added to the biomass.

20. The method of claim 16, wherein the base is added to the biomass as a solid.

21. The method of claim 16, wherein the base and the biomass are mixed in a section of the extruder downstream from the second port.