HIGH EFFICIENCY GASIFICATION

Abstract

A gasification reactor for conversion of a feedstock to syngas and biochar. The gasification reactor includes a biomass input configured to receive feedstock, a gasifying medium inlet adjacent to the biomass input and configured to receive a gasifying medium, and a reactor vessel configured to gasify the feedstock with the gasifying medium to generate syngas and biochar. The reactor vessel is disposed downstream of the gasifying medium inlet. The reactor vessel may comprise cement along an inner surface of the reactor vessel. The reactor vessel may further comprise a blower coupled to the gasifying medium inlet to drive the gasifying medium into the reactor vessel. The reactor vessel may further comprise a biomass movement instrument to regulate the flow of the feedstock.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application entitled “High Efficiency Gasification,” filed on Aug. 24, 2023, and assigned Ser. No. 63/534,552 the entire disclosure of which is hereby expressly incorporated by reference.

BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

The disclosure relates generally to gasification.

Brief Description of Related Technology

As the amount of fossil fuels available decreases and the cost of petroleum-based fuels increases, there is a greater need for alternative fuel sources. One promising process for biofuel production involves the formation of fuel flammable gas, also known as synthesis gas (syngas for short) which can then be converted to useful compounds.

Synthesis gas (syngas) is formed by a variety of processes with sources ranging from commonly-used fossil fuels to completely renewable organic compounds such as biomass feedstock material. Biomass includes organic material such as agricultural waste, plant residues, wood chips, and the like. The vast array of feedstocks is one promising aspect of the use of syngas to produce fuel. The main components of syngas are carbon monoxide, carbon dioxide, hydrogen, and methane. Each of these components can be converted into valuable products. While multiple pathways exist for the transformation of these products, most of the conversions are performed by microbial or thermochemical processes.

Biochar is a carbon-rich solid that is derived from biomass that is heated in a limited oxygen environment. Biochar can be intended for agricultural use, and is typically applied as a soil amendment, which is defined as any material that is added to soil to improve its physical properties, such as water and nutrient retention. Because biochar contains a stabilized form of carbon, studies have shown that biochar has the technical potential to make a substantial contribution to climate change mitigation.

Current technology enables production of either a high yield of syngas (energy) or more biochar.

SUMMARY OF THE DISCLOSURE

In accordance with one aspect of the disclosure, a gasification reactor for conversion of a feedstock to syngas and biochar includes a biomass input configured to receive feedstock, a gasifying medium inlet adjacent to the biomass input and configured to receive a gasifying medium, and a reactor vessel configured to gasify the feedstock with the gasifying medium to generate syngas and biochar. The reactor vessel is disposed downstream of the gasifying medium inlet.

In accordance with another aspect of the disclosure, a gasification reactor for conversion of a feedstock to syngas and biochar includes a biomass input configured to receive feedstock, a gasifying medium inlet configured to receive a gasifying medium, and a reactor vessel configured to gasify the feedstock with the gasifying medium to generate syngas and biochar. The reactor vessel comprises cement along an inner surface of the reactor vessel.

In accordance with another aspect of the disclosure, a gasification reactor for conversion of a feedstock to syngas and biochar includes a biomass input configured to receive feedstock, a gasifying medium inlet configured to receive a gasifying medium, a reactor vessel configured to receive and gasify the feedstock with the gasifying medium to generate syngas and biochar, and a blower coupled to the gasifying medium inlet to drive the gasifying medium into the reactor vessel.

In accordance with another aspect of the disclosure, a method for converting a feedstock to syngas and biochar includes receiving, by a biomass input of a gasification reactor, the feedstock, receiving, by a gasifying medium inlet adjacent to the biomass input, a gasifying medium; and gasifying, by a reactor vessel, the feedstock with the gasifying medium to generate syngas and biochar. The reactor vessel is disposed downstream of the gasifying medium inlet.

In accordance with another aspect of the disclosure, a method of fabricating a gasification device includes providing a biomass input configured to receive a feedstock, disposing a gasifying medium inlet adjacent to the biomass input configured to receive a gasifying medium, disposing a firetube downstream of the gasifying medium inlet configured to gasify the feedstock with the gasifying medium to generate syngas and biochar, lining an inner space of the firetube with a wall layer of cement, lining an outer space of the firetube with a layer of mild steel, and disposing a blower upstream of the firetube. The blower is configured to inject the gasifying medium into the firetube.

In connection with any one of the aforementioned aspects, the devices and/or methods described herein may alternatively or additionally include or involve any combination of one or more of the following aspects or features. The reactor vessel includes cement along an inner surface of the reactor vessel. The reactor vessel further includes a reaction chamber configured to receive heat and to process the feedstock and the gasifying medium and a refractory layer wall surrounding the reaction chamber. The refractory layer wall comprises cement. The cement includes hydraulic cement. The reactor vessel further includes an outer shell including mild steel. The refractory layer wall includes a layer wall of cement that is thicker than the outer shell. The gasification reactor further comprises a blower coupled to the gasifying medium inlet to drive the gasifying medium into the reactor vessel. The gasifying medium inlet is coupled to the blower disposed upstream of the reactor vessel and the blower injects the gasifying medium to the gasifying medium inlet. The blower injects the gasifying medium to the gasifying medium inlet using slight pressure of up to 4 psi above atmospheric pressure. The blower includes a regenerative blower. The gasification reactor includes a reaction controller coupled with the blower and configured to control the blower to regulate an amount of the gasifying medium that is injected by the blower into the gasifying medium inlet. The feedstock and the gasifying medium flow in the same direction. The gasification reactor further includes a feed controller and a biomass movement instrument coupled with the feed controller and the biomass input. The feed controller is configured to control the biomass movement instrument to cause the feedstock to flow downward from the biomass input to the reactor vessel; and regulate the flow of the feedstock into the reactor vessel. The gasification reactor may further comprise a biochar chamber configured to store the biochar and the biochar chamber may be disposed below the reactor vessel. The biomass movement instrument is disposed at the bottom of the reactor vessel and above the biochar chamber. The biomass movement instrument includes a shaker assembly and the shaker assembly is disposed at the bottom of the reactor vessel. The biomass movement instrument includes a screw conveyor, a rotary valve, or any combination thereof, disposed below the reactor vessel.

The method of converting a feedstock to syngas and biochar further comprises regulating, by a biomass movement instrument, a flow of the feedstock into the reactor vessel; and storing, by a biochar chamber, the biochar.

The method of fabricating a gasification device further comprises disposing a biomass movement instrument to regulate a flow of the feedstock into the firetube.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

For a more complete understanding of the disclosure, reference should be made to the following detailed description and accompanying drawing figures, in which like reference numerals identify like elements in the figures.

FIG. 1 depicts a gasification reactor in accordance with one example.

FIG. 2 depicts a gasification reaction implemented by the gasification devices described herein in accordance with one example.

FIG. 3 is a flow diagram of a method of generating syngas and biochar in accordance with one example.

FIG. 4 is a flow diagram of a method of fabricating a gasification reactor in accordance with one example.

FIG. 5 depicts a gasification reactor in accordance with one example.

FIG. 6 depicts a gasification reactor in accordance with one example.

FIG. 7 depicts a gasification reactor in accordance with one example.

FIG. 8 depicts a gasification reactor in accordance with one example.

FIG. 9 depicts a table summarizing the performance of a gasification reactor in accordance with one example.

The embodiments of the disclosed devices and methods may assume various forms. Specific embodiments are illustrated in the drawings and hereafter described with the understanding that the disclosure is intended to be illustrative. The disclosure is not intended to limit the invention to the specific embodiments described and illustrated herein.

DETAILED DESCRIPTION OF THE DISCLOSURE

A gasification reactor that provides methane enriched syngas and flexible biochar production is described. Methods of operating and fabricating such a gasification reactor are also described.

The disclosed gasification reactors include a number of features that lead to an increase in energy density and, as an additional benefit, lower the production cost. Further, the disclosed gasification reactors produce a higher quantity of biochar than traditional gasifiers. In one aspect, one or more components of the main chamber of the gasification reactor are composed of, or otherwise include refractory cement. In another aspect, the gasification reactor is driven by a blower and operates under slight pressure (up to 120 inches of water or 4 psi above atmospheric pressure). For instance, a gasifying medium may be introduced under slight pressure at a gasifying medium inlet, throat, or a restriction in the top of the gasification reactor. In another aspect, separate controls for feedstock flow and gasifying medium regulation allow for high resolution control of reaction dynamics. The disclosed devices may include any combination of these and other features.

Gasification refers to a technological process that converts biomass into fuel syngas. Gasification occurs in a gasification reactor (gasifier). A gasifier is a high temperature/pressure vessel where a gasifying medium like oxygen, air or steam are directly contacted with the biomass feedstock material causing a series of chemical reactions to occur that convert biomass to syngas and ash/slag (mineral residues). A byproduct of the gasification process is biochar. Current gasifier technology enables production of either a high yield of syngas (energy) or more biochar.

In particular, the specific yield from pyrolysis, one of the processes that occur in a gasifier explained further below, is dependent on process conditions such as temperature, residence time, and heating rate. These parameters can be tuned to produce either energy or biochar. Temperatures of 400-500° C. (673-773 K) produce more biochar, whereas temperatures above 700° C. (973 K) favor the yield of liquid and gas fuel components. Pyrolysis occurs more quickly at higher temperatures, typically requiring seconds rather than hours. The increasing heating rate leads to a decrease of biochar yield, while the temperature is in the range of 350-600° C. (623-873 K). Typical yields are 60% bio-oil, 20% biochar, and 20% syngas. By comparison, slow pyrolysis can produce substantially more char (≈35%). This contributes to soil fertility. Once initialized, both processes produce net energy.

Syngas has a variety of uses. Syngas can be further converted (or shifted) to nothing but hydrogen and carbon dioxide (CO₂) by adding steam and reacting over a catalyst in a water-gas-shift reactor. When hydrogen is burned, it creates nothing but heat and water, resulting in the ability to create electricity with no carbon dioxide in the exhaust gases. Furthermore, hydrogen made from coal or other solid fuels can be used to refine oil, or to make products such as ammonia and fertilizer. More importantly, hydrogen enriched syngas can be used to make gasoline and diesel fuel. Carbon dioxide can be efficiently captured from syngas, preventing its greenhouse gas emission to the atmosphere, and enabling its utilization (such as for enhanced oil recovery) or safe storage.

Gasifiers come in many varieties, each with a unique operational design. In particular several types of currently available gasifiers include fluidized bed, up-draft, down-draft, and Imbert.

Fluidized bed gasifiers make use of fluidization to create a reactor bed. The reactor is initially filled with solid, dry feedstock particles and then air, oxygen, or steam is blown upwards through the bed at a steadily increasing rate. When the local velocity of the oxidizing agent reaches the average terminal settling velocity of the particles, the feedstock particles become fully suspended in the fluid stream, behaving very similarly to a liquid. Therefore, feedstock particles have been “fluidized.” Feedstock particles are more suitable for mid-to large-scale operations. Further, feedstock particles are difficult to operate because their use is dependent on sustaining a very delicate equilibrium state. Fluidized bed gasifiers are also only suited for feedstocks that have very high ash-fusion temperatures (i.e., ash melting points), because slag production can cause the fluidized bed particles to stick together, which raises their terminal settling velocity and ruins the fluidization effect. The fluidized bed gasifiers require dry feedstock that has been grinded down into smaller particles (less than 6 mm). The fluidized bed gasifiers also operate at very high temperatures, making them suitable for the gasification of high rank coals, and have better throughputs than the fixed-bed types.

The up-draft gasifier is designed to accept fuel and oxidant from the bottom of the gasifier and flow counter to the direction of the feedstock. This design creates a very intense combustion zone in the region in which the two streams first meet, resulting in very high temperatures. These high temperatures can lead to damage to the gasifier components, such as the grate that prevents un-gasified feedstock from falling to the bottom with the ash. Thus, it is often necessary to use steam or a gaseous coolant to protect sensitive areas of the gasifier. The high temperature gases act as a natural drying agent for the entering feedstock, which means that (1) fuels with higher moisture content can be used, including raw biomass and (2) up-draft gasifiers have higher carbon conversion rates than down-draft gasifiers. This allows the syngas to exit at a much lower temperature than in down-draft gasifiers, resulting in less waste heat. The devolatilization occurs at relatively low temperatures above the gasification zone, resulting in copious amounts of tar, phenols, and ammonia that must be separated from the syngas before downstream applications.

The down-draft gasifier is designed to accept fuel and oxidant from the top of the gasifier and both flow co-currently toward the bottom while chemical reactions occur. This has several implications. First, the highest gas temperatures in the entire reactor will occur in the pyrolysis zone. Since the pyrolysis zone is above the combustion zone, all volatiles and tars pass through the high temperatures (more than 1,800° F.) of the combustion zone, and result in their destruction via cracking and oxidation. The high temperature gas entering the reduction zone promotes the endothermic gasification reactions in the reduction zone, cooling the gas to 1,100 to 1,200° F. There is a fair amount of waste heat associated with this type of gasifier and it generally has low carbon conversion rates (about 94%); however, because of this, leftover char can be sold as a byproduct. It is difficult to scale up, because of the heat flow in the opposite direction of the gas flow, which creates eddies. Commercial applications are limited to date to biomass gasifiers smaller than 1 megawatt-thermal (MWth). Due to the low maximum temperature (highest in pyrolysis zone), most of the ash will tend to be fly ash.

The Imbert Gasifier is a down-draft gasifier. The upper cylindrical portion of the Imbert gasifier unit is simply a storage bin or hopper for wood chips or other biomass fuel. During operation, this chamber is filled every few hours as needed. The spring-loaded, airtight cover must be opened to refill the fuel hopper. Specifically, the airtight cover must remain closed and sealed during gasifier operation. The spring permits the cover to function as a safety valve because it will pop open in case of any excessive internal gas pressure. About one-third of the way up from the bottom of the gasifier unit, there is a set of radially directed air nozzles; these inject air into the fuel or biomass as it moves downward to be gasified. In a gas generator for vehicle use, the downstroke of the engine's pistons creates the suction force which moves the air into and through the gasifier unit; during startup of the gasifier, a blower is used to create the airflow. The gas is introduced into the engine and consumed a few seconds after it is made. This gasification method is called “producer gas generation” because no storage system is used. Instead, only the amount of gas demanded by the engine is produced. When the engine is shut off, the production of gas stops.

In most gasifier designs, a gasifier reactor operates under a vacuum with blowers upstream from the reaction pulling a gasifying medium through the reactor. Gasification reactors are generally made from stainless steel because steel can withstand high temperatures and pressures that are required for the gasification process. In particular most gasification reactors follow a construction design of stainless-steel inner tube, i.e., a fire tube, and a stainless mild steel outer shell where operating temperatures allow it.

Gasification refers to thermal breaking of chemical bonds to rearrange compounds into syngas. In a gasifier, a gasifying medium such as air, is injected and biomass undergoes several different processes and/or reactions while heat is applied. The different processes include drying, torrefaction, pyrolysis, combustion, reduction, and gasification. Drying refers to the process of removing moisture from biomass. Torrefaction is a thermal pretreatment process to pretreat biomass in the temperature range of about 200-300° C. Torrefaction removes some moisture and volatile organic compounds from biomass. Pyrolysis occurs when heat is applied to biomass in the temperature range of about 400-600° C. in the absence of oxygen. During pyrolysis, biomass is thermally decomposed to release oils and tars while the biomass is converted to mostly carbon. A byproduct of the pyrolysis process is biochar. The combustion process occurs, at a temperature range of about 1000° C.-1200° C., as the volatile products and some of the carbon react with oxygen to primarily form carbon dioxide (CO₂) and small amounts of carbon monoxide (CO), which provides heat for the subsequent gasification reactions. Reduction refers to the process of removing oxygen. The remaining carbon acts as a catalyst and reacts with CO₂ and steam to produce syngas, which is composed primarily of the colorless, odorless, highly flammable gases carbon monoxide (CO) and hydrogen (H₂) with some traces of methane (CH₄).

Pyrolysis is often compared to gasification. Pyrolysis is one of the reactions occurring in the gasifier. In general, pyrolysis kilns usually work at lower temperatures and less sophistication resulting in a higher biochar yield but little to no energy is recovered. In some cases, external energy must be supplied.

The efficiency of the gasification process may vary in many ways but relies on several factors: the atmosphere (level of oxygen or air or steam content) in the gasifier; the design of the gasifier; the internal and external heating means; and the operating temperature for the process. Factors that affect the quality of the product gas may include feedstock composition, preparation, and particle size, gasifier heating rate, residence time, the plant configuration, the feedstock-reactant flow geometry, the design of the dry ash or slag mineral removal system; whether it uses a direct or indirect heat generation and transfer method; and the syngas cleanup system.

The disclosed gasification reactors are capable of fuel generation of a higher energy density. For instance, in one example, syngas resulting from the disclosed gasification reactor exhibited 5 to 10 times the concentration of methane reported in the literature. At the same time, the gasification reactor produced relatively high quantities of biochar and was capable of balancing the co-products (syngas and biochar) to maximize the decarbonization potential of the gasification technology and its biomass feedstock. The positive pressure, shielded walls, and/or other aspects of the disclosed gasification reactors thus lead to improved performance relative to traditional reactors, such as the Imbert and the Downdraft (FEMA) designs.

FIG. 1 shows a gasification reactor or gasifier 100 for producing syngas 102 and biochar 104 in accordance with one example. The gasification reactor 100 includes a biomass input 106 configured to receive a feedstock 108. The biomass input 106 may include an upper cylindrical portion, a storage bin, a hopper, or a feeding silo. The feedstock 108 may include biomass and may be dry and/or pelletized.

The gasification reactor 100 further includes a gasifying medium inlet 110 disposed under or adjacent to the biomass input 106. The gasifying medium inlet 110 may include a throat, restriction, or a constriction 107 as shown in FIG. 6 described below. The gasifying medium inlet 110 is configured to receive a gasifying medium 112. The gasifying medium 112 may include air, oxygen, steam, carbon dioxide, or a mixture of them.

The gasification reactor 100 includes a containing reactor vessel or firetube 114. The gasification reactor 100 may further include a biomass movement instrument 134 that controls the flow of feedstock 108 from the biomass input 106 to the reactor vessel 114. The gasification reactor 100 may further include a blower 126 that controls the flow of the gasifying medium 112 to the reactor vessel 114 via the gasifying medium inlet 110. The gasifying medium 112 flows in the appropriate quantities in the same direction as the feedstock 108. The reactor vessel 114 further includes a reaction chamber 120, a refractory layer wall 122, and an outer shell 124. In particular, the feedstock 108 is loaded in the biomass input 106. The feedstock 108 and the gasifying medium 112 are fed into the reaction chamber 120 where an initial fire is started via a lighting port (not shown). Once the fire is started, the lighting port is closed and the gasification reaction starts. The gasification reactor 100 may be operated in a semi-batch or fully continuous mode. Energy output is continuous during the batch, and operation is made to match customers' operations energy demand. The gasifying medium 112 may be used to manipulate the gasification reaction. In an example, the combustion is regulated by the amount of the gasifying medium 112 provided. The reaction is self-sustaining.

The reaction chamber 120 may be lined with the refractory layer wall 122 and the outer shell 124. The refractory layer wall 122 may include a layer wall of cement. The cement may include hydraulic cement. In an embodiment, the refractory layer wall 122 may include a layer wall of concrete. The refractory layer wall 122 eliminates the need for an outer stainless steel shell used in current gasifiers. The refractory layer wall 122 enables a catalytic effect and significant cost reductions. For example, the layer wall of cement in contact with the feedstock 108, the gasifying medium 112, and heat may cause an increase in the Methane (CH₄) content of the syngas 102. On the other hand, the layer wall of cement allows for the use of outer mild steel shell in the reactor vessel 114 and the elimination of the outer stainless steel shell around reactor vessel 114. These are significant materials savings which in turn further achieve economic savings. Further, the elimination of the need for an outer stainless steel shell makes the monitoring of the reaction in the reactor vessel 114 much simpler. Thermowells, thermocouples, pressure sensors and other instruments may be inserted through only one layer of material instead of having to perforate two layers (the shell and the reactor) and having to be aligned. Again, this makes the cost of construction lower.

The blower 126 is disposed upstream of the reactor vessel 114. The blower 126 injects or pushes the gasifying medium 112 into the reactor vessel 114 and operates under slight pressure. In particular, the blower 126 pushes the gasifying medium 112 into the reactor vessel 114 instead of sucking air out of the reactor vessel 114 to create a vacuum.

The gasification reactor 100 may further include an unheated gasifying medium path 111 that connects the blower 126 to the gasifying medium inlet 110. The blower 126 pushes the gasifying medium 112 into the gasifying medium inlet 110 via the unheated gasifying medium path 111. In an embodiment, the unheated gasifying medium path 111 does not receive any heat. Therefore, the gasifying medium 112 is fed by the blower 126 to the gasifying medium inlet 110 via the unheated gasifying medium path 111 at room temperature.

In another embodiment, the gasification reactor 100 may include a heated gasifying medium path 113 that connects the blower 126 to the gasifying medium inlet 110. In this embodiment, the heated gasifying medium path 113 may include a shell that surrounds the reactor vessel 114 that is preheated through an indirect heat exchange. Therefore, the gasifying medium 112 is preheated before being injected into the gasifying medium inlet 110.

In an embodiment, the blower 126 injects the gasifying medium 112 via only one of the unheated gasifying medium path 111 or the heated gasifying medium path 113.

The gasification reactor 100 avoids the challenges arising from the utilization of high suction blowers to drive the gasifying medium 112 through the reactor vessel 114. For instance, the gasification reactor 100 does not have a significant distance between the blower 126 and the reactor vessel 114, which helps avoid small clogs or problems leading to large drops in pressure. The gasification reactor 100 also does not operate in a vacuum, which can present a safety concern as any leak in the reactor vessel 114 can result in oxygen infiltration and an internal explosion when the oxygen meets the syngas 102 at high temperatures and presence of sparks.

Operating the blower 126 upstream from the reaction eliminates these problems. The disclosed design of the gasification reactor 100 significantly cuts the distance between the air (gasifying medium 112) and the reaction, reducing concerns of pressure loss. In one example, the blower 126 may include a regenerative blower. A regenerative blower is more resilient to changes in pressure and is able to maintain a relative air volume under some changes in pressure. Having the blower 126 operate upstream from the reaction means low operating temperatures and ability to use cheaper blowers. Further, no tar is introduced to the blower 126 reducing the maintenance and fouling significantly. Operating the gasification reactor 100 at a slight pressure ensures that any leaks in the reactor vessel 114 result in syngas 102 being expelled in the atmosphere and reduces chances of explosions. Since the reactor vessel 114 is not operated in a vacuum, air leaks of syngas 102 out of the reactor vessel 114 due to pressure are much easier to detect.

The gasifying medium 112 is introduced under slight pressure at the gasifying medium inlet 110 in the top of the reactor vessel 114 via the unheated gasifying medium path 111 or the heated gasifying medium path 113.

The gasification reactor 100 enables the injection of the gasifying medium 112 at the gasifying medium inlet 110 underneath the biomass input 106 which avoids having to introduce the gasifying medium 112 at the top of the gasification reactor 110 which prevents the problem of the gasifying medium 112 having to travel through the whole column of feedstock 108 before reaching the reactor vessel 114. The injection of the gasifying medium 112 underneath the biomass input 106 further avoids having to inject the gasifying medium 112 at the point of the combustion layer of the reactor vessel 114. In particular the gasifying medium inlet 110 is disposed between the biomass input 106 and the reactor vessel 114. In other words, the gasifying medium inlet 110 is disposed downstream of the biomass input 106 and the reactor vessel 114 is disposed downstream of the biomass input 106. This ensures that the gasifying medium 112 travels only through the reactor vessel 114, preheating and assisting the torrefaction and pyrolysis reactions before reaching the combustion process to generate the biochar 104 and the syngas 102.

In some embodiments, the gasification reactor 100 may further include a biochar chamber 132 configured to store the biochar 104. In an embodiment, the biomass chamber 132 may be disposed below the reaction vessel 114. In an embodiment, the heated gasifying medium path 113 surrounds the biochar chamber 132 to be preheated.

The gasification reactor 100 may further include a biomass movement instrument 134 configured to regulate the flow of the feedstock 108. In one embodiment, the biomass movement instrument 134 may include a variable frequency motor 118 which may be used to regulate the flow of the feedstock 108. The gasification reactor 100 further includes a feed controller 128 to control the biomass movement instrument 134 to regulate the flow of the feedstock 108. The feed controller 128 is configured to allow for high resolution control of reaction dynamics. The feed controller 128 is configured to control the biomass movement instrument 134 to cause the feedstock 108 to flow downward from the biomass input 106 to the reactor vessel 114 and regulate/control the flow of the feedstock 108 into the reactor vessel 114. The feed controller 128, the biomass movement instrument 134, and the variable frequency motor 118 together facilitate the high production of biochar 104 in this gasifier.

In some embodiments, as shown in FIGS. 1, 2, and 6, the biomass movement instrument 134 may include a shaker assembly 135 disposed at the bottom of the reactor vessel 114 above the biochar chamber 132. In particular, the shaker assembly 135 may be disposed below the combustion layer of the reactor vessel 114.

In some embodiments, as shown in FIG. 7, the biomass movement instrument 134 may include a screw, e.g., a screw conveyor, a rotary valve 136, or any combination thereof, disposed below the reactor vessel 114 of a gasification reactor 700. The screw conveyor may include a horizontal, vertical or inclined screw conveyor. The rotary valve 136 may include a rotary lock, a rotary feeder, a rotary airlock valve, and the like. The rotation of the screw conveyor or rotary valve 136 regulates the flow of the feedstock 108 and maintains a consistent flow rate.

In some embodiments, as shown in FIG. 7, the biochar chamber 132 may be disposed separate from the gasification reactor 700.

In some embodiments, as shown in FIG. 8, a gasification reactor 800 does not include a biochar chamber 132. Biochar 104 and syngas 102 may be moved out and exit the gasification reactor 800. In some embodiments, syngas 102 and biochar 104 may exit the gasification reactor 800 via one or more output exits as described. For example, as shown in FIG. 8, syngas 102 may exit and pass through a first output exit 138 of the gasification reactor 800 and biochar 104 may exit and pass through a second output exit 140 of the biomass movement instrument 134.

The gasification reactor 100 further includes a reaction controller 130. In an example, the reaction controller 130 is coupled with the blower 126. The blower 126 may include another variable frequency motor/driver (not shown). In this example, the reaction controller 130 is configured to control the blower 126 to regulate an amount of the gasifying medium 112 that is injected into the gasifying medium inlet 110.

In an example, one or more of the feed controller 128 and the reaction controller 130 may control the blower 126 and/or the biomass movement instrument 134 to regulate modulation of various parameters of gasification including equivalence ratio, superficial velocity, feedstock residence time, and feedstock flow. In an example, the feed controller 128 and the reaction controller 130 may be integrated into any desired extent.

The feed controller 128 and the reaction controller 130 may include a processor and a plurality of sensors coupled with the processor. The processor may be configured to determine gasification parameter measurements based on data obtained by the plurality of sensors.

The feed controller 128 and the reaction controller 130 may include one or more processors such as a central processing unit (CPU). The feed controller 128 and the reaction controller 130 may thus include multiple controllers or processors for respectively controlling, directing, or otherwise communicating with one or more of the plurality of sensors.

The processor of the feed controller 128 and the reaction controller 130 may be a component in a variety of systems. The processor may be one or more general processors, digital signal processors, application specific integrated circuits, field programmable gate arrays, networks, digital circuits, analog circuits, combinations thereof, or other now known or later developed devices for analyzing and processing data. The processor may implement a software program, such as code generated manually (i.e., programmed).

The feed controller 128 and the reaction controller 130 may include one or more memories or storage units. The memory may communicate via a bus. The memory may be a main memory, a static memory, or a dynamic memory. The memory may include but may not be limited to computer readable storage media such as various types of volatile and non-volatile storage media, including but not limited to random access memory, read-only memory, programmable read-only memory, electrically programmable read-only memory, electrically erasable read-only memory, flash memory, and the like. In one case, the memory may include a cache or random access memory for the processor. Alternatively, or additionally, the memory may be separate from the processor, such as a cache memory of a processor, the system memory, or other memory. The memory may be an external storage device or database for storing data. Examples may include a hard drive, memory card, memory stick, or any other device operative to store data. The memory may be operable to store instructions executable by the processor. The functions, acts or tasks illustrated in the figures or described herein may be performed by the programmed processor executing the instructions stored in the memory. The functions, acts or tasks may be independent of the particular type of instruction set, storage media, processor or processing strategy and may be performed by software, hardware, integrated circuits, firm-ware, micro-code and the like, operating alone or in combination. Likewise, processing strategies may include multiprocessing, multitasking, parallel processing and the like.

Alternatively, or additionally, dedicated hardware implementations, such as application specific integrated circuits, programmable logic arrays and other hardware devices, may be constructed to implement one or more of the methods described herein. Applications that may include the apparatus and systems of various embodiments may broadly include a variety of electronic and computer systems. One or more embodiments described herein may implement functions using two or more specific interconnected hardware modules or devices with related control and data signals that may be communicated between and through the modules, or as portions of an application-specific integrated circuit. Accordingly, the present system may encompass software, firmware, and hardware implementations.

FIG. 2 schematically depicts a gasification reaction 200. FIG. 5 shows a flow of biomass/feedstock and air in a gasification reactor 500 according to an embodiment. The gasification reaction 200 may be implemented by the gasification reactor 500 or another device described herein such as the gasification reactors 100, 500, 600, or 700 shown in FIGS. 1 and 5-7.

As shown in FIGS. 2 and 5, input reagents including the biomass/feedstock 108 and the gasifying medium 112, e.g., O₂, are fed into the gasification reactor 300 where heat is applied. Syngas 102 and biochar 104 are generated as output products. Tars and water (H₂O) may also be released. The gasification reactor 500 may be configured to control some of the parameters that affect the composition of the different output products including syngas 102 and the biochar 104. In an example, the reaction controller 130 may cause the blower 126 to control the equivalence ratio which refers to the amount of oxygen O₂ supplied to the reaction as a fraction of the amount of oxygen O₂ required for full combustion of the feedstock 108. In another example, the reaction controller 130 may cause the blower 126 to control the superficial velocity which refers to the linear speed of the gasifying medium 112 (air) through the geometry of the reactor vessel 114. The gasification reactor 500 may further control the reaction temperature and pressure via one or both of the feed controller 128 and the reactor controller 130.

Since the gasification reaction 200 that takes place within the gasification reactor 500 is non-reversible, different parameters such as the contact time and retention time of the input reagents in the gasification reactor 500 affect the composition of the different output products. Accordingly, the equivalence ratio of the input reagents is tied to the superficial velocity. However, the superficial velocity is not affected by the rate of flow of the biomass 108. Therefore, the retention time may be further controlled by controlling the equivalence ratio of the reagents including the gasifying medium 112 and the biomass 108. By using different variable frequency drive motors on the blower 126 and the biomass movement instrument 134 (variable frequency drive motor 118), a broader span and finer control of contact and retention time may be achieved.

Since the gasification reaction 200 is a non-reversible reaction, the feed controller 128 may control reagent residence time in the reactor vessel 114. Since the equivalence ratio and the superficial velocity are tied to each other, the contact time may be controlled by the feed controller 128 and the reaction controller 130 which control both the gasifying medium 112 and the feedstock 108.

FIG. 3 depicts an example method 300 of generating syngas 102 and biochar 104 via a gasification reactor 100 as may be implemented by the components such as those described with respect to FIG. 1. Embodiments may involve all, more or fewer actions indicated by the blocks of FIG. 3. The actions may be performed in the order or sequence shown or in a different sequence.

The method 300 may begin with an act 302 in which a feedstock 108 is loaded to a biomass input 106. In an act 304, feedstock 108 is received by the biomass input 106. In act 306, the amount and flow of the feedstock 108 is controlled by a feeding controller. In act 308, a gasifying medium 112 is received by a gasifying medium inlet 110. In act 310 the amount and flow of gas is controlled by a reaction controller. In act 312, the feedstock 108 and the gasifying medium 112 are received and gasified by a reactor vessel 114. In act 314, syngas 102 and biochar 104 are generated.

FIG. 4 depicts an example method 400 of fabricating a gasification reactor 600 shown in FIG. 6. Embodiments may involve all, more or fewer actions indicated by the blocks of FIG. 4. The actions may be performed in the order or sequence shown or in a different sequence.

The method 400 may begin with an act 402 in which a biomass input 106 is provided to receive feedstock 108. In an act 404, a constriction/throat 107 is disposed adjacent to the biomass input 106 to receive a gasifying medium 112 via alternative paths including either an un-heated air path 111 or a preheated air path 113. In an act 406, a firetube or reactor vessel 114 is disposed downstream of the gasifying medium inlet 110. In act 408, an inner space of the firetube 114 is lined by a layer wall of cement. In act 410, an outer space of the firetube 114 is lined by a layer wall of mild steel. In act 412, a blower 126 is disposed upstream of the firetube 114. The blower 126 is configured to control the flow of the gasifying medium 112. In an act 413, a biomass movement instrument 134 is disposed at the bottom of the firetube 114. The biomass movement instrument 134 is configured to control the flow of the feedstock 108. The biomass movement instrument 134 may include a shaker assembly 135 as shown in FIGS. 1, 5, and 6, a screw conveyor or rotary valve 136 as shown in FIGS. 7 and 8, or any combination thereof. In various embodiments, the method 400 may be used to fabricate gasification reactors 100, 500, and 700 as shown in FIGS. 1, 5, and 7.

FIG. 9 depicts a table 900 summarizing the performance of the disclosed gasification reactor in accordance with one example. The performance is presented in comparison with commercially available gasifiers in the market. The disclosed gasification reactor achieved unexpected results in both the production of biochar 104 and the concentration of Methane (CH₄) in the syngas 102.

These results show that the disclosed gasification reactor achieves the highest energy density of any reactor currently available while maintaining a high level of biochar 104. The disclosed gasification reactor provides higher carbon efficiency by producing less CO and more CH₄ with similar biochar 104 production. Therefore, the disclosed gasification reactor is also more energy efficient than others.

The term “about” is used herein in a manner to include deviations from a specified value that would be understood by one of ordinary skill in the art to effectively be the same as the specified value due to, for instance, the absence of appreciable, detectable, or otherwise effective difference in operation, outcome, characteristic, or other aspect of the disclosed methods and devices.

The present disclosure has been described with reference to specific examples that are intended to be illustrative only and not to be limiting of the disclosure. Changes, additions and/or deletions may be made to the examples without departing from the spirit and scope of the disclosure.

Also, the terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting of the disclosure. Singular expressions include plural expressions unless the context clearly indicates otherwise. As used herein, the terms “comprise”, or “have” are intended to designate that the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification are present. The terms do not preclude the existence or addition of one or more other features or numbers, steps, operations, components, parts or combinations thereof in advance.

The references attached to the steps are used to identify the steps. These references do not indicate the order between the steps. Each step is performed in a different order than the stated order unless the context clearly indicates a specific order.

Computer-readable recording media may include all kinds of recording media having stored thereon instructions which can be read by a computer. For example, there may be a read only memory (ROM), a random-access memory (RAM), a magnetic tape, a magnetic disk, a flash memory, an optical data storage device, and the like.

Further, when an element in the written description and claims is described as being “for” performing or carry out a stated function, step, set of instructions, or the like, the element may also be considered as being “configured to” do so.

The foregoing description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom.

Claims

1. A gasification reactor for conversion of a feedstock to syngas and biochar, the gasification reactor comprising:

a biomass input configured to receive feedstock;

a gasifying medium inlet adjacent to the biomass input and configured to receive a gasifying medium; and

a reactor vessel configured to gasify the feedstock with the gasifying medium to generate syngas and biochar, wherein the reactor vessel is disposed downstream of the gasifying medium inlet.

2. The gasification reactor of claim 1, wherein the reactor vessel comprises cement along an inner surface of the reactor vessel.

3. The gasification reactor of claim 1, wherein the reactor vessel comprises:

a reaction chamber configured to receive heat and to process the feedstock and the gasifying medium; and

a refractory layer wall surrounding the reaction chamber.

4. The gasification reactor of claim 3, wherein the refractory layer wall comprises cement.

5. The gasification reactor of claim 4, wherein the cement includes hydraulic cement.

6. The gasification reactor of claim 3, wherein the reactor vessel further includes an outer shell including mild steel.

7. The gasification reactor of claim 6, wherein the refractory layer wall includes a layer wall of cement that is thicker than the outer shell.

8. The gasification reactor of claim 1, further comprising:

a blower coupled to the gasifying medium inlet to drive the gasifying medium into the reactor vessel.

9. The gasification reactor of claim 1,

wherein the gasifying medium inlet is coupled to a blower disposed upstream of the reactor vessel, and

wherein the blower injects the gasifying medium to the gasifying medium inlet.

10. The gasification reactor of claim 9, wherein the blower injects the gasifying medium to the gasifying medium inlet using slight pressure of up to 4 psi above atmospheric pressure.

11. The gasification reactor of claim 9, wherein the blower includes a regenerative blower.

12. The gasification reactor of claim 9, further comprising:

a reaction controller coupled with the blower and configured to control the blower to regulate an amount of the gasifying medium that is injected by the blower into the gasifying medium inlet.

13. The gasification reactor of claim 1, wherein the feedstock and the gasifying medium flow in the same direction.

14. The gasification reactor of claim 1, further comprising:

a feed controller; and

a biomass movement instrument coupled with the feed controller and the biomass input, wherein the feed controller is configured to control the biomass movement instrument to: cause the feedstock to flow downward from the biomass input to the reactor vessel; and regulate the flow of the feedstock into the reactor vessel.

15. The gasification reactor of claim 14,

wherein the gasification reactor further comprises a biochar chamber configured to store the biochar, the biochar chamber disposed below the reactor vessel,

wherein the biomass movement instrument includes a shaker assembly, and

wherein the shaker assembly is disposed at the bottom of the reactor vessel and above the biochar chamber.

16. The gasification reactor of claim 14,

wherein the biomass movement instrument includes a screw conveyor, a rotary valve, or any combination thereof, disposed below the reactor vessel.

17. A method for converting a feedstock to syngas and biochar, the method comprising:

receiving, by a biomass input of a gasification reactor, the feedstock;

receiving, by a gasifying medium inlet adjacent to the biomass input, a gasifying medium; and

gasifying, by a reactor vessel, the feedstock with the gasifying medium to generate syngas and biochar, wherein the reactor vessel is disposed downstream of the gasifying medium inlet.

18. The method of claim 17, further comprising:

regulating, by a biomass movement instrument, a flow of the feedstock into the reactor vessel; and

storing, by a biochar chamber, the biochar.

19. A method of fabricating a gasification device, the method comprising:

providing a biomass input configured to receive a feedstock;

disposing a gasifying medium inlet adjacent to the biomass input, wherein the gasifying medium inlet is configured to receive a gasifying medium;

disposing a firetube downstream of the gasifying medium inlet, wherein the firetube is configured to gasify the feedstock with the gasifying medium to generate syngas and biochar;

lining an inner space of the firetube with a wall layer of cement;

lining an outer space of the firetube with a layer of mild steel; and

disposing a blower upstream of the firetube, wherein the blower is configured to inject the gasifying medium into the firetube.

20. The method of claim 19, further comprising:

disposing a biomass movement instrument to regulate a flow of the feedstock into the firetube.