Patent Application
20150191653
The present invention is directed towards clean energy, and more particularly, some embodiments of the invention provide systems, apparatuses, and methods for biomass fractioning.
In the early 21st century, global warming and its interrelationship with the widespread use of fossil fuels has become one of the major technological challenges. Finding ways to more effectively use renewable biomass is a very important option for addressing these issues. Prior to the beginning of the industrial revolution, wood and plant oils were the primary source of energy for pre-industrial civilizations, which used this energy mainly for heating, cooking, and light. During this early period, biomass was simply burned in open air to produce heat and light. Several thousand years ago, man discovered that if the air supply was restricted during the burning process, a dense black residue (which we now call coke) could be extracted from burning wood. This hot coke could be quenched with water, dried, and re-burnt to produce a much hotter, denser fire. The emergence of coke proceeds in parallel with the development of metallurgy, which is dependent upon its hotter and cleaner fire along with its reducing capabilities to both extract metals from ore and form them into useful products. The process of roasting a combustible material in either a reduced oxygen environment or oxygen-free environment is now called pyrolysis. Pyrolyzing wood and other forms of mixed biomass produces coke (which is sometimes called biochar) and a mixture of hydrogen, carbon monoxide and carbon dioxide, sometimes referred to as syngas. Roasting fossil fuel hydrocarbons in an oxygen-free environment first causes a breakdown of longer chain hydrocarbons into shorter chain hydrocarbons, ultimately resulting in more elemental forms such as methane (CH4), hydrogen, and elemental carbon. In fact, pyrolysis is a fundamental mechanism of petrochemical cracking, which is the backbone of oil refinery processes. More extreme pyrolysis is used in the refinery process to produce hydrogen and high purity carbon.
Likewise, biomass (which is made up of cellulose, hemi-celluloses, lignin, starches, lipids, and minerals) proceeds through multiple steps of decomposition when subject to the pyrolysis process. In general, when subject to high temperatures (e.g., 800° C.) for prolonged periods of time, pyrolysis ultimately yields syngas (a combination of CO and hydrogen). As the temperature and exposure time interval is reduced, an increasing amount of carbonaceous residue remains, and this is known as biochar. At still lower temperatures and time intervals, increasingly complex hydrocarbons and oxygenated hydrocarbons are present in the gas stream from the pyrolyzed biomass. At the low extreme, simple everyday cooking typically drives off water and starts to de-hydrolyze the biomass, causing the darkening and carmelization that we all associate with cooked foods.
Small scale commercial biomass pyrolyzers have been developed to generate useful chemical products from the controlled pyrolysis of biomaterials ranging from wood chips to sewage sludge. Recent developments have resulted in systems capable of processing biomass under milder pyrolyzing conditions, which typically result in a condensed liquid commonly known as bio-oil or pyrolysis oil.
A type of biomass pyrolyzer described in this invention can dispense the biomass into thin sheets, which are subject to carefully controlled processing conditions, e.g., temperature, pressure, local gas composition, so that the biomass can be fractionated into a bio-oil with a desired composition. However, the bio-oil is typically released in vapor form, and both the bio-oil and biomass intermediate compositions can harm the moving mechanical components of the fractionation system. In addition, the particulate nature of the biomass makes the fractionation system prone to clogging.
Various embodiments of this invention provide systems, apparatuses, and methods for biomass fractioning that address the challenges of biomass pyrolysis as detailed above while still utilizing the fundamental mechanism of heating biomass materials in a reduced oxygen, neutral or reducing environment. Certain embodiments of invention may be referred to as biomass fractionators.
Some embodiments of the invention involve dispensing ground biomass into thin sheets for further processing. The process is scalable in that it can be expanded in two dimensions to any practical working throughput while retaining a constant thickness for heat treatment of incoming materials.
Certain biomass fractionators of the invention consist of a sealed pyrolysis chamber that separates the fractionation area from the remainder of the systems (e.g., biomass feed system, biochar recovery system, downstream bio-oil conversion systems, etc.) that make up one possible biomass fractionator. In some of these embodiments, the motors that power the system and the sensors that monitor and control the system can also be maintained outside of this sealed pyrolysis chamber. Biomass fractionators of these embodiments can have an internal conveying surface that moves the thin sheet of biomass through each processing station. The conveying surface can be designed to have interlocking portions with side walls that overlap. In certain embodiments the conveying surface can be a conveyor belt. These embodiments have the benefit of reducing clogging associated with normal biofractionator systems.
Other embodiments of the invention involve subjecting individual portions of biomass sheets to carefully controlled ramps of temperature versus time, pressure and local working gas composition, in order to selectively extract various groups of compounds from the processed biomass. In this manner, the biomass pyrolysis products are effectively fractionated into various working streams, much like a crude oil cracking tower separates incoming fossil crude into various working streams.
The various embodiments of the invention provide for an improved biofractionation system that separates sensitive motors and control sensors from the harsh environment of the pyrolysis chamber. This reduces maintenance costs because the sensitive components are not exposed to the high heat and pressure of the pyrolysis chamber. In addition, these components are not exposed to the biofractionation products (e.g. bio-oil components) that consist of strong solvents that can degrade the components of a motor or sensor. In addition, a conveying surface system with interlocked tracks and overlapping side walls more effectively contains the biomass during processing and is easier to clean than standard systems allowing for longer processing times without clogging. Each of these improvements, alone or in combination, results in increased overall longevity of the system, increased time between maintenance and repairs, and increased overall efficiency of the system because of longer processing times.
Certain embodiments of the system also provide for the stacking of multiple fractionators to allow for a reduced number of motors to power the fractionator systems. These stackable fractionator systems can also be stacked on movable platforms to allow them to be delivered directly to the source of the biomass (e.g. the harvest field) and run directly on site. This eliminates the costly step of shipping bulky, low energy content, biomass and instead allows for the high energy content bio-oil to be produced and shipped for further processing. In still a further embodiment the biomass fractionator of the invention is connected to a catalyst system that converts the biofractionation products into higher value bio-oil components.
In one embodiment, the invention is a system for biomass fractioning with a sealed pyrolysis chamber containing at least one conveying surface; a dispenser for introducing biomass into the sealed pyrolysis chamber; a plurality of processing stations, where each station comprises a piston, each piston sealingly positioned in an opening of the sealed pyrolysis chamber above the conveying surface. The pistons are connected to the driver located external to the sealed pyrolysis chamber. The driver is capable of moving the pistons in and out of contact with the conveying surface. There is a heater for heating at least a portion of the conveying surface; a drive motor located external to the sealed pyrolysis chamber to drive the conveying surface; at least one vapor exhaust port for directing vapors from the sealed pyrolysis chamber; and a removal station for receiving material from the conveying surface and removing material from the sealed pyrolysis chamber.
In another embodiment, the system has the plurality of pistons that are housed within a piston block. In a further embodiment, there are O-rings that create an airlock seal between each piston and the piston block. In still another embodiment, each piston is connected to the driver by a spring-loaded piston arm. In another embodiment, the plurality of pistons are heated.
In yet another embodiment, the bio-vapor exhaust port further comprises an inlet feed line. In one further embodiment, the driver is a crankshaft.
In another embodiment, the heater comprises electrical heating elements, direct flame combustion, directed jets of heated working gas, heat transfer fluid, or directed jets of supercritical fluid.
In a further embodiment, the biofractionator has a second drive motor connected to the crankshaft to drive the crankshaft. In one embodiment, the location of each of the pistons is determined by the drive of the crankshaft.
In another embodiment, the conveying surface is made of a plurality of interconnected plates. In a further embodiment, the interconnected plates have sidewalls extending upward from the horizontal surface of the surface. In still another embodiment, the side walls of the interconnected plates overlap.
In another embodiment, the biofractionator has an entry port. In a further embodiment, the entry port is connected to a dispenser. In yet another embodiment, the dispenser is a rotary valve. In another embodiment, the rotary valve is connected to a hopper. In a further embodiment, the hopper contains biomass. In another embodiment, the material removed from the system is biochar.
In one embodiment, there is an apparatus for fractioning biomass with at least one dispenser for dispensing biomass into a first biofractionator and a second biofractionator; the first biofractionator and the second biofractionator each being comprised of, a sealed pyrolysis chamber containing at least one conveying surface; a dispenser for introducing biomass into the sealed pyrolysis chamber; a plurality of processing stations, where each station comprises a piston, each piston sealingly positioned in an opening of the sealed pyrolysis chamber above the conveying surface, where the pistons are connected to at least one driver located external to the sealed pyrolysis chamber. And the driver is capable of moving the pistons in and out of contact with the conveying surface. The biofractionators further have a heater for heating at least a portion of the conveying surface; a drive motor located external to the sealed pyrolysis chamber to drive the conveying surface; at least one vapor exhaust port for directing vapors from the sealed pyrolysis chamber; and a removal station for receiving material from the conveying surface and removing material from the sealed pyrolysis chamber; where the two biofractionators are in a stacked configuration such that the drivers of the first and second fractionators are run by one drive motor.
In another embodiment, the apparatus for fractioning biomass has the plurality of pistons that are housed within a piston block. In a further embodiment, there are O-rings that create an airlock seal between each piston and the piston block. In still another embodiment, each piston is connected to the driver by a spring-loaded piston arm. In another embodiment, the plurality of pistons are heated.
In yet another embodiment, the apparatus for fractioning biomass bio-vapor exhaust port further comprises an inlet feed line. In one further embodiment the driver is a crankshaft.
In another embodiment, the apparatus for fractioning biomass heater comprises electrical heating elements, direct flame combustion, directed jets of heated working gas, heat transfer fluid, or directed jets of supercritical fluid.
In a further embodiment, the apparatus for fractioning biomass biofractionator has a second drive motor connected to the crankshaft to drive the crankshaft. In one embodiment, the location of each of the pistons is determined by the drive of the crankshaft.
In another embodiment, the apparatus for fractioning biomass conveying surface is made of a plurality of interconnected plates. In a further embodiment, the interconnected plates have sidewalls extending upward from the horizontal surface of the surface. In still another embodiment, the side walls of the interconnected plates overlap.
In another embodiment, the apparatus for fractioning biomass biofractionator has an entry port. In a further embodiment, the entry port is connected to a dispenser. In yet another embodiment, the dispenser is a rotary valve. In another embodiment, the rotary valve is connected to a hopper. In a further embodiment, the hopper contains biomass. In another embodiment, the material removed from the system is biochar.
In one embodiment, the invention is a method for converting biomass to bio-oil that includes the steps of moving biomass on the conveying surface through a plurality of processing stations each comprising a piston that is sealingly positioned in an opening in said sealed pyrolysis chamber; heating at least a portion of the conveying surface; moving the pistons into contact with the conveying surface; compressing the biomass between each piston and the conveying surface releasing volatiles from the biomass via the compression of each piston; directing the volatiles out of the sealed pyrolysis chamber via at least one vapor exhaust port; collecting the volatile components from the at least one vapor exhaust port; advancing the biomass through the plurality of processing stations via the conveying surface; receiving non-volatile material from the last processing station via the at least one conveying surface; and removing said non-volatile material from the sealed pyrolysis chamber.
In another embodiment, the method of converting biomass has the plurality of pistons that are housed within a piston block. In a further embodiment, there are O-rings that create an airlock seal between each piston and the piston block. In still another embodiment, each piston is connected to the driver by a spring-loaded piston arm. In another embodiment, the plurality of pistons are heated.
In yet another embodiment, the method of converting biomass bio-vapor exhaust port further comprises an inlet feed line. In one further embodiment the driver is a crankshaft.
In another embodiment, the method of converting biomass heater comprises electrical heating elements, direct flame combustion, directed jets of heated working gas, heat transfer fluid, or directed jets of supercritical fluid.
In a further embodiment, the method of converting biomass biofractionator has a second drive motor connected to the crankshaft to drive the crankshaft. In one embodiment, the location of each of the pistons is determined by the drive of the crankshaft.
In another embodiment, the method of converting biomass conveying surface is made of a plurality of interconnected plates. In a further embodiment, the interconnected plates have sidewalls extending upward from the horizontal surface of the surface. In still another embodiment, the side walls of the interconnected plates overlap.
In another embodiment, the method of converting biomass further comprises the step of dispensing biomass into the sealed pyrolysis chamber. In another embodiment, the method of converting biomass further comprises the step of removing said non-volatile material from said sealed pyrolysis chamber. In still another embodiment, the non-volatile material is biochar.
The present invention, in accordance with one or more various embodiments, is described in detail with reference to the following figures. The drawings are provided for purposes of illustration only and merely depict typical or example embodiments of the invention. These drawings are provided to facilitate the reader's understanding of the invention and shall not be considered limiting of the breadth, scope, or applicability of the invention. It should be noted that for clarity and ease of illustration these drawings are not necessarily made to scale.
Some of the figures included herein illustrate various embodiments of the invention from different viewing angles. Although the accompanying descriptive text may refer to such views as “top,” “bottom” or “side” views, such references are merely descriptive and do not imply or require that the invention be implemented or used in a particular spatial orientation unless explicitly stated otherwise.
The figures are not intended to be exhaustive or to limit the invention to the precise form disclosed. It should be understood that the invention can be practiced with modification and alteration, and that the invention be limited only by the claims and the equivalents thereof.
The following diagrams and description present examples of the invention, but in no way limit the application of the concepts. The following designs are simply illustrative of their application.
In one embodiment of the present invention, a biomass fractioning apparatus is provided. In another embodiment of the present invention, a system for biomass fractioning in an efficient manner is provided. In still a further embodiment, a method for biomass fractioning biomass to obtain renewable bio-oils is provided.
As used herein, the term ‘biomass’ includes any material derived or readily obtained from plant sources. Such material can include without limitation: (i) plant products such as bark, leaves, tree branches, tree stumps, hardwood chips, softwood chips, grape pumice, sugarcane bagasse, switchgrass; and (ii) pellet or chopped material such as grass, wood and hay pellets, crop products such as corn, wheat and kenaf. This term may also include seeds such as vegetable seeds, fruit seeds, and legume seeds.
The term “biomass” can also include: (i) waste products including animal manure such as poultry derived waste; (ii) commercial or recycled material including plastic, paper, paper pulp, cardboard, sawdust, timber residue, wood shavings and cloth; (iii) municipal waste including sewage waste; (iv) agricultural waste such as coconut shells, pecan shells, almond shells, coffee grounds; and (v) agricultural feed products such as rice straw, wheat straw, rice hulls, corn stover, corn straw, and corn cobs. Biomass is typically comprised of a wide array of compounds classified within the categories of cellulose, hemicelluloses, lignin, starches, and lipids. Biomass can also be comprised of plant residue, seed residue and seed cake, the left over material after oil extraction from the seeds.
The various embodiments of the invention are related to improved, systems, methods and apparatuses for the biofractionation of biomass. Known biofractionators have many problems that make them inefficient and prone to fouling and breakdowns. For example, the prior art systems often have complicated mechanical systems to deliver the biomass to the fractionator units. These systems can clog with biomass and the system must be routinely shut down to clear this clogging. Also, the known biofractionators require complicated sensors to be within the pyrolysis chamber during operation. These sensors are sensitive to fouling from the various bio-oils that are produced and must be routinely cleaned. This cleaning requires the system to be shut down, which reduces its efficiency. Also, the motors that drive the various components of the known biofractionators are often within the pyrolysis chamber as well. These motors can be sensitive to the high heat, pressure, and the volatile products made during fractionation. This results in the need for more frequent maintenance and repair of the motors. Finally, known biofractionator systems use individual chambers to process the biomass at each fractionator. These individual chambers are prone to clogging and must be thoroughly cleaned prior to reuse. The known systems that are designed to accomplish this cleaning in situ are ineffective and will often leave residue behind that will eventually foul the system resulting in a shut down.
As will be discussed in further detail below, the present invention in its various embodiments provides a biofractionation system with a separate pyrolysis chamber(s) that is sealed and segregated from the sensors and motors that are used to control and drive the system. In addition, the current system provides an efficient biomass delivery system within the pyrolysis chamber that allows for complete processing of the biomass and greatly reduces the chance that the biomass residue will clog the system thereby preventing a system shutdown.
Additional sensors are also not needed for the present invention because the system can be monitored based on the mechanical relationship between the conveying surface (4), the pistons (3) and the drive motor or motors that control them. As depicted in
As mentioned above, the pyrolysis chamber (1) also contains the conveying surface (4) for moving the biomass through each processing station (10). It further contains a heating system (6) to heat the conveying surface (4) and the biomass. The system illustrated in
As shown in
The system in
As shown in
In one embodiment the conveying surface (4) is heated via a single bottom heating plate (6) held at a constant temperature as shown in
In one specific embodiment of
Further discussing
Various combinations of temperature profile, pressure and working gas phase or supercritical media can be utilized to extract various compounds such as (i) long chain dehydrated sugars; (ii) lignin derived aromatics; (iii) lipid based oils; (iv) carbohydrate based furans; (v) shorter hydrocarbons; (vi) oxygenates such as butane, butanol, acetone, acetylaldehyde, aldehyde, methane, methanol, etc.; and (vii) ultimate syngas components (hydrogen, carbon monoxide, and carbon dioxide). At each successive processing stage, the station can be heated to a higher temperature via the various heating schemes known in the art, and the material is compacted to a thinner layer with an increasing level of elemental carbon in the remaining biomass. As each portion of biomass is advanced to the next processing station the hopper and rotary valve can load additional biomass on the surface of the conveying. The system can be designed with as many fractionator stations as needed depending on the type of the biomass being processed. As such, the description of this continuous stepping process will not be repeated in conjunction with the stations to follow, but is implied in their operation.
Continuing with reference to
Once the biochar is removed from the conveying surface, the cleaned conveying surface then advances back to the initial fill station and is advanced through the fractionator stations as described herein throughout the normal operation of the biomass fractionator. As shown in
In an embodiment of the present invention, no pre-heating or de-watering is required. Instead, each biofractionation station is used to pyrolyze the biomass by pressing it under heat and pressure. If desired each station can be set at different temperatures to alter the volatile components that are removed from the biomass. The time that each station is under compression will be varied based on the number of stations, the type of biomass, the thickness of the biomass being compressed, etc. Each of these variables is adjusted so that full pyrolysis is obtained before the biomass reaches the scraping knife or brush. The pressure applied on the biomass can also be adjusted according to the spring strength in the piston arms. In each station, bio-vapor is produced that is useful for catalytic upgrading.
One illustrative example of a biofractionator system of the present invention would use a biofractionator with 12″×x 18″ pistons that are held a relatively constant 650° C. Each biofractionator would have 10 fractionation stations (e.g. 10 pistons) pressing ˜0.5 inches of biomass at a pressure of 0.6 g/cm3 for 6 second intervals. Using 4 of these fractionators or two sets of two stacked fractionators as described in
Another illustrative example of a biofractionator system of the present invention would use the same biofractionator apparatus discussed above in Example 1, but would have 40 fractionators or 20 stacked fractionator systems and would produce 1,000,000 gallons of bio-oil a year at a processing rate of 2.5 tons/hr of biomass processed.
In a still further example of a biofractionator system of the present invention the system would use the same biofractionator apparatus discussed above in Example 1, but would have 400 rows or 200 stacked fractionator systems. This would produce 10,000,000 gallons of bio-oil per year at a biomass processing rate of 25 tons/hr.
The examples above are just illustrative of embodiments of the present invention. The variables associated with the pyrolysis (number of fractionators, temperature at which pyrolysis is performed, pressure exerted by the planten, thickness of the biomass, length of time the biomass is being compressed by each planten, etc.) can be adjusted to maximize the bio-oil produced from a particular biomass.
Various embodiments of the invention are specifically designed to operate in a supercritical environment. Generally, supercritical fluid environments provide both a substantial improvement in heat transfer as compared to gaseous environments and a substantial increase in chemical reaction rates, as compared to liquid environments due to their much, much higher rate of diffusion. Specifically, embodiments are designed to operate with supercritical carbon dioxide, supercritical water, methane, methanol and other small hydrocarbons, their oxygenates, and mixtures of the above such as 60% CO2, 30% water, 10% methane and other organics. The following table lists the supercritical parameters for some key constituents.
While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not of limitation. Likewise, the various diagrams may depict an example architectural or other configuration for the invention, which is done to aid in understanding the features and functionality that can be included in the invention. The invention is not restricted to the illustrated example architectures or configurations, but the desired features can be implemented using a variety of alternative architectures and configurations. Indeed, it will be apparent to one of skill in the art how alternative functional, logical or physical partitioning and configurations can be implemented to implement the desired features of the present invention. Also, a multitude of different constituent module names other than those depicted herein can be applied to the various partitions. Additionally, with regard to flow diagrams, operational descriptions and method claims, the order in which the steps are presented herein shall not mandate that various embodiments be implemented to perform the recited functionality in the same order unless the context dictates otherwise.
Although the invention is described above in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations, to one or more of the other embodiments of the invention, whether or not such embodiments are described and whether or not such features are presented as being a part of a described embodiment. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments.
Terms and phrases used in this document, and variations thereof, unless otherwise expressly stated, should be construed as open ended as opposed to limiting. As examples of the foregoing: the term “including” should be read as meaning “including, without limitation” or the like; the term “example” is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof; the terms “a” or “an” should be read as meaning “at least one,” “one or more” or the like; and adjectives such as “conventional,” “traditional,” “normal,” “standard,” “known” and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass conventional, traditional, normal, or standard technologies that may be available or known now or at any time in the future. Likewise, where this document refers to technologies that would be apparent or known to one of ordinary skill in the art, such technologies encompass those apparent or known to the skilled artisan now or at any time in the future.
A group of items linked with the conjunction “and” should not be read as requiring that each and every one of those items be present in the grouping, but rather should be read as “and/or” unless expressly stated otherwise. Similarly, a group of items linked with the conjunction “or” should not be read as requiring mutual exclusivity among that group, but rather should also be read as “and/or” unless expressly stated otherwise. Furthermore, although items, elements or components of the invention may be described or claimed in the singular, the plural is contemplated to be within the scope thereof unless limitation to the singular is explicitly stated.
The presence of broadening words and phrases such as “one or more,” “at least,” “but not limited to” or other like phrases in some instances shall not be read to mean that the narrower case is intended or required in instances where such broadening phrases may be absent.
Additionally, the various embodiments set forth herein are described in terms of exemplary block diagrams, flow charts and other illustrations. As will become apparent to one of ordinary skill in the art after reading this document, the illustrated embodiments and their various alternatives can be implemented without confinement to the illustrated examples. For example, block diagrams and their accompanying description should not be construed as mandating a particular architecture or configuration.
This application claims the benefit of U.S. Provisional Application No. 61/925,500, filed Jan. 9, 2014, the contents of which are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61925500 | Jan 2014 | US |
