JP2017186565A - Method and device for the gasification of feedstock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for gasification of solid biomass, household and industrial waste, fossil fuel, and other carbon-containing feedstock by utilizing downward stream gasification for perfect gasification and suppression of carbide by-products.SOLUTION: Provided is a gasification device including: a thermodecomposition zone 20 which is at least 3 consecutive reaction zones formed by utilizing a plurality of tubes disposed in the vertical direction, an oxidation zone 30 which is under the thermodecomposition zone and a reduction zone 40 which is under the oxidation zone; at least two rings 31,32 which are planar air inlets disposed in the oxidation zone for injecting air; and a fire grate 50 which is rotary type and adjustable in vertical direction disposed under the reduction zone but not in contact with the reduction zone, and which is a partially-opened core type downward stream gasification device used for the gasification of a feedstock.SELECTED DRAWING: Figure 1

Description

  [0001] The present invention relates to thermochemical techniques and equipment, and in particular, gasifies solid biomass, household and industrial waste, fossil fuels and other carbon-containing feedstocks using downflow gasification. The present invention relates to a process and an apparatus.

  [0002] Gasification is a continuous pyrolysis process in which a substance consisting of solid organic matter or carbon (feedstock) is broken down into a combustible gas mixture. The components of the combustion gas formed are mainly carbon monoxide (CO), hydrogen (H2) and methane (CH4). Other non-combustion gases, nitrogen (N2), water vapor (H2O) and carbon dioxide (CO2) are also present in varying amounts. The gasification process is accompanied by pyrolysis followed by partial oxidation, which is controlled by injecting air or other oxygen-containing gas into the partially pyrolyzed feedstock. . More specifically, biomass gasification is a series of reactions including water evaporation, lignin degradation, deflagration of cellulose derivatives and carbon reduction. An external heat source initiates this reaction, but partial oxidation provides heat to maintain thermal decomposition of the feedstock. When concentrated oxygen is used, the resulting gas mixture is called synthesis gas. When air (including nitrogen) is used as the oxidant, the resulting gas mixture is referred to as generator gas. For simplicity, the term “generator gas” as used herein will include both synthesis gas and generator gas. Both gas mixtures are considered “fuel gases” and can be used in place of natural gas in many processes. They can also be used as precursors to produce various industrial chemicals and motor fuels. When biomass is used as a feedstock, gasification and combustion of the generator gas is considered to be a source of renewable energy.

  [0003] As a general matter, gasification provides a more efficient, cost-effective and environmentally friendly alternative for extracting potential energy from solid feedstocks compared to combustion. As a result of gasification, the potential energy of the feedstock can be converted into generator gas, which is cleaner and more combustible, compressible and more portable. Reactor gas may be burned directly on some engines and burners, purified to produce methanol and hydrogen, or converted to synthetic liquid fuel by the Fischer-Tropsch process and other methods and processes. is there.

  [0004] There are three general gasification processes: fluidized bed gasification, upward flow gasification, and downward flow gasification. The present invention is an improved downflow gasifier. Thus, only a brief description of fluidized bed gasification and upflow gasification is provided, after which the current downflow gasification is more fully considered.

[0005] Upstream gasification
[0006] A fixed bed of flow (upstream) gasifier consists of a fixed bed of feedstock at the top of a large grate where water vapor, oxygen and / or air flow upwards. Upstream gasifiers typically require a feedstock that forms a permeable bed because they are sturdy and not prone to clumping or clumping. Upstream gasifiers consist of a bed of feedstock through which oxidants (water vapor, oxygen and / or air) enter through the bottom and exit as a gas through the top. Upstream gasifiers have high thermal efficiency, because the rising gas pyrolyzes and drys the incoming biomass and moves the heat away, so that the generated reactor gas exits the gasifier. The reason is that it is cooled when going. However, there is a significant amount of tar in the generator gas, so such tar must be removed extensively before use if it is not burned during production. Tar can be recycled to the gasifier, but tar removal is complex and costly. Upstream gasifiers have been a staple of coal gasification for 150 years and are also common in biomass cooking ranges.

[0007] Fluidized bed gasification
[0008] In fluidized bed gasification, the oxidant is blown at a rate sufficient to hold the solid particles in suspension such that they pass through the bed of solid particles. The feedstock is charged to the gasifier and mixed with the bed material very quickly and heated almost instantaneously to the bed temperature either externally or using a heat transfer medium. Most such fluidized bed gasifiers are equipped with an internal cyclone to minimize carbides (carried into the generator gas stream) and to remove the fluidizing medium from the generator gas. Key benefits include the ability to easily control feed adaptability and reaction temperature, which allows gasification of finely granulated materials (such as sawdust) without the need for pre-treatment Become. The fluidized bed gasifier also scales very well to large sizes. Unfortunately, supply problems, bed instability, residual carbon and ash build-up sinter into the gas channel and the like. Other drawbacks include high tar content of the generator gas (up to 500 mg / m 3 gas), relatively low efficiency and blunt response to load changes. Due to high operating and maintenance costs, this type of gasification is economically limited to large scale applications, typically over 100 tons per day.

[0009] Downstream gasification
[0010] In downflow gasification, all feedstock, air and gas flow in the same direction, ie from top to bottom. Upstream gasification is typically preferred for biomass feedstock processing and fluid bed gasification is typically used for coal gasification, although the downflow gasification process has several advantages . One advantage of downflow gasification is that only low levels of tar are produced in the resulting generator gas, which means that the tar produced in the pyrolysis is oxidized (hereinafter referred to as the oxidation zone) before leaving the gasifier. This is because it is necessary to pass through a carbide bed in the reduction zone (defined below). High temperatures at the oxidation zone and the top of the carbide bed decompose tar (ie, pyrolysis). The result is a generator gas that can be cooled and more easily cleaned for use in reciprocating engines, gas combustion turbines and catalytic reforming processes.

  [0011] Current downflow gasification processes have several significant disadvantages that prevent their widespread adoption. These disadvantages are: (1) Feedstocks generally have similar chemical properties to allow continuous gasification without filling device gaps (ie, destabilizing) without degrading the quality of the reactor gas. (2) The feedstock must have a standard range of volatile components (without mixing different types of feedstocks or different size elements) (3) The feedstock needs to have a standardized heat content (ie btu / lb), (4) In general, the gasifier is an excess that accumulates at the bottom of the cleaning and gasifier (5) The generated reactor gas is inconsistent in quality, and the gasifier is subject to temperature changes caused by frequent shutdowns and feedstock fluctuations. Due to raw Low productivity and low efficiency, (6) The gasifier cannot be reconfigured during operation and must be stopped each time the oxidation reaction moves from its designated location in the gasifier Some (7) gasifiers are not thermally stable over time and lose efficiency (or melt), and (8) gasifiers gasify different types of feedstocks at different ratios. In order to compensate for the different conditions required to produce the components of the generator gas, the location of the oxidation reaction cannot be moved in parallel with the reduction zone. However, the most significant disadvantages of current downflow gasifiers are (9) that these gasifiers require the loading action of the hearth, so that the oxidation zone, and the hottest zone of the gasifier, It is designed to have a substantially limiting point (ie, a limit of approximately half the diameter of the other section of the gasifier).

  [0012] In an ideal downflow gasifier, there are three zones: a pyrolysis zone, an oxidation zone and a reduction zone (each defined below). In such an ideal gasifier, (1) the residence time of the feedstock is oxidized so that the maximum amount of feedstock can undergo gasification before leaving the oxidation zone and proceeding to the reduction zone. Can be managed in the zone (relative to the feed stream through the rest of the gasifier), and (2) the reduction zone can cause the hot gas produced in the oxidation zone to be as quickly as possible in the reduction zone and It is designed to promote complete gasification by mixing with carbides as completely as possible. Unfortunately, the restricted areas in current gasifiers interfere with the total volume of feed that can be moved through such gasifiers, interrupting the overall flow and power of the reactor gas. .

  [0013] The restricted areas found in the prior art are commonly referred to as the top and hearth, which are intentional designs in current downflow gasifiers required by the preferred theory, namely superficial velocity theory. is there.

[0014] The superficial velocity (SV) is
[0015] SV = gas production rate / cross-sectional area = (m3 / s) / (m2) = m / s
Is measured as
[0016] s = time and m = distance.

  [0017] When superficial velocity theory is used to design a downflow gasifier, a higher superficial gas velocity in the oxidation zone means cleaner generator gas and less carbide by-products. Require that it be generated.

  [0018] The physical limitations required by superficial velocity theory in the oxidation zone itself limit both the feedstock inlet and outlet in conventional downflow gasifiers. It is preferred to control the feed rate in the restricted zone throughout the remainder of the gasifier independent of its rate, thereby promoting perfect gasification and reducing the formation of carbide by-products.

  [0019] What is needed is a feedstock flow rate that passes through the gasifier by allowing the flow rate of the feedstock to be managed as it passes through the oxidation zone with its minimal limitations. Downstream gasifier design that improves overall volume and flow.

  [0020] The following is a summary description of the invention. This description is provided as an introduction to help those of ordinary skill in the art to incorporate more detailed discussion more quickly, and this introduction follows and is not intended to limit the scope of the claims in any way. Not intended, and the following claims are appended hereto to point out the present invention in detail.

  [0021] The disclosed invention is a gasifier comprising a plurality of tubes that are coupled and arranged vertically. These tubes have inner and outer walls and proximal and distal ends, the proximal end providing an inlet and the distal end providing an outlet. The gasifier has three separate reaction zones: (1) a pyrolysis zone, (2) an oxidation zone under the pyrolysis zone, and (3) a reduction zone under the oxidation zone. A rotating vertically adjustable grate is placed under the reduction zone but is not mounted in the reduction zone. Unlike other gasifiers, this is a partially open core type gasifier without a gas tight seal at the distal end of the gasifier.

  [0022] Optionally, a drying zone is positioned over the pyrolysis zone, so that the heat of the gasifier can be utilized to dry the feed before the feed enters the gasifier. . During operation, feedstock is fed to the pyrolysis zone (directly or via a drying zone). Gravity moves the feedstock down through the three reaction zones and gasifies the generator gas and carbon ash and the remaining byproducts formed after the biomass feedstock is gasified (“biochar”) Exit through the grate at the bottom of the device and enter the collection chute. Biochar is separated from the generator gas by gravity.

  [0023] The reactor gas also exits through the grate and is collected by collection vents on either side of the collection chute. The pressure in the collection chute is a correlative element of the piping lines connected to the gas collection vents and the machinery (ie, engine, collection chamber, etc.) attached to such piping lines downstream of the gasifier. The gasifier pressure does not depend on the pressure of the collecting chute.

It is a notch front view of a gasifier. It is a notch side view of a gasifier. It is a front view of the outer side of a gasifier. It is a side view of the outer side of a gasifier. FIG. 2 is a cutaway front view of a gasifier with dimensions indicated in inches. FIG. 2 is a cutaway side view of a gasifier with dimensions shown in inches. It is a notch side view which shows the highest density part of a guidance inclination and an inflow inclination. It is a notch perspective view which shows the highest density part of a guidance inclination and an inflow inclination. It is a notch side view of the gasifier provided with the oxidation zone. It is a notch perspective view of the gasifier provided with the oxidation zone. It is a perspective view of a grate frame. It is a top view of a grate frame. It is a perspective view of the grate after the assembly which has a spiral groove. FIG. 6 is a perspective view of an assembled grate having holes cut out in the grate. FIG. 3 is a perspective view of a removable segment of a grate. FIG. 4 is a top view of a removable segment of a grate. It is a notch side view of the gasifier which has the arrow which draws a gasification process.

[0041] Definition
[0042] The following list of defined terms is not intended to be limiting or exhaustive, but merely provides a quick reference for understanding the present invention. Other defined terms are capitalized in other sections of this document where those terms are used. Terms that begin with a capital letter should include all variations, ie, single and / or multiple forms of the terms used herein.

  [0043] "Bed oxidant stream" or "bed air" is an oxidation that enters the gasifier through an inlet (ie, a non-movable inlet) located at the top of the pyrolysis zone (or optional drying zone). Refers to the drug stream.

  [0044] "Bio charcoal" refers to carbon ash and the remaining byproducts that are formed after the biofeed is gasified.

  [0045] "Bypass" refers to the "gap" between the top of the grate located below the gasifier and the opening at the bottom of the reduction zone, this gap is also called the pitch of the grate In some cases.

  [0046] A "control system" refers to an operating system that allows a user and / or operator to vary a gasifier such as grate rotation and height, feedstock and oxidant stream input. A plurality of control mechanisms and cooperating software.

  [0047] "Drying zone" refers to an area where, with respect to the gasifier, the feedstock is dried before entering the pyrolysis zone, which is above a certain container or pyrolysis zone. It is an extension of the gasifier, but alternatively the drying zone may be a region and / or a component / unit remote from the gasifier. In the context of a gasification process, “drying zone” means the stage where the feedstock is dried.

  [0048] The "gasifier flow lane" is generally towards the center of the gasifier and is the place where the feedstock moves and is gasified the fastest, and the resulting reactor gas and biochar are in the reduction zone It means a path that moves inward and continues to move out of the gasifier through the grate.

  [0049] "Oxidant stream" refers to air or other oxygen-containing gas.

  [0050] "Oxidation zone" refers to the location where the main gasification reaction takes place with respect to the gasifier. The oxidation zone is where the oxidant stream combines with the heat from the gasifier and converges in the presence of the feedstock, which is a narrow white hot gas that extends across the diameter of the gasifier. The feedstock is rapidly oxidized in the zone. In the context of a gasification process, the “oxidation zone” refers to the hottest stage of the gasification reaction.

  [0051] "Oxidation zone" refers to a particular zone of a gasifier that, with respect to the gasifier, leads up to and away from the oxidation zone. The overall shape of the oxidation zone is a hollow tube that has an inlet and outlet that are approximately the same size but widened in the middle. In the context of a gasification process, an “oxidation zone” refers to the stage where a feedstock is converted to a gas.

  [0052] "Planar air inlet" refers to a pressurized air inlet used to inject a pressurized oxidant stream into a gasifier. In existing gasifiers, tuyere is used to allow air to passively enter the gasifier, while the planar air inlet is used to inject the oxidant stream into the gasifier. Instead it is pressurized.

  [0053] "Planar oxidant stream" or "planar air" refers to an oxidant stream that enters the gasifier through a planar air inlet.

  [0054] "Pressure lock" refers to a pressure lock assembly that includes a valve at the top of the pressure lock assembly and another valve at the bottom of the pressure lock assembly.

  [0055] "Pressure wave" refers to the pressure difference between the center of the oxidation zone and the wall of the oxidation zone, and this pressure wave pushes the feed towards the wall of the gasifier and from the oxidation zone An induction gradient of the feedstock (inclination of the induced feedstock) is formed above, and an inflow gradient of biochar (gradient of the inflowing biochar) is formed below the oxidation zone.

  [0056] "Generator gas" refers to a combustion gas mixture formed by gasification of a feedstock and includes synthesis gas and generator gas.

  [0057] "Purge oxidant stream" or "purge air" refers to an oxidant stream that is mixed with a feed before the feed enters the pyrolysis zone (or optional drying zone).

  [0058] "Pyrolysis zone" refers to the zone of a gasifier where, with respect to the gasifier, the feedstock begins to fluidize and crack before proceeding to the oxidation zone. The overall shape of the pyrolysis zone may range from a hollow tube to an inverted hollow cone. In the context of a gasifier process, a “pyrolysis zone” refers to the stage where a feedstock begins to fluidize and crack.

  [0059] "Reduction zone" refers to a gasifier zone where, with respect to the gasifier, the generator gas mixes with biochar and cools to form additional generator gas. The overall shape of the reduction zone is a hollow tube, which is wider than the exit of the oxidation zone. In the context of a gasification process, the “reduction zone” refers to the stage where the generator gas mixes with biochar.

[0060] Overview of gasifier area
[0061] The present invention relates to a method and apparatus for gasifying a biomass feedstock containing carbon. The gasifier comprises a plurality of tubes that are connected and arranged vertically. These tubes have inner and outer walls and proximal and distal ends, the proximal end providing an inlet and the distal end providing an outlet. The gasifier has three consecutive separate reaction zones: (1) a pyrolysis zone, (2) an oxidation zone below the pyrolysis zone, and (3) a reduction zone below the oxidation zone. . A rotating vertically adjustable grate is placed under the reduction zone but is not mounted in the reduction zone. Unlike other gasifiers, it is a partially open core gasifier without an airtight bottom wall that seals the reduction zone or the bottom of the gasifier itself.

  [0062] FIGS. 1 and 2 show cutaway front views of a gasifier. The downflow gasifier is a continuous, co-current, gravity assisted, thermochemical phase change gasifier having at least three zones, a pyrolysis zone 20, an oxidation zone 30 and a reduction zone 40. . The gasifier oxidizes a portion of the feedstock, thereby releasing sufficient thermal activation energy into the generator gas to initiate a phase change from thermochemical solids to gas of the remaining feedstock. The gasification process is a series of reactions including water evaporation, lignin decomposition, deflagration of cellulose derivatives and carbon reduction and is managed by injecting an oxidant stream into a partially pyrolyzed feedstock. . Although the present invention will be described in the context of a method and apparatus for treating biomass, the principles described may be applied to many other types of feedstocks and various embodiments will be readily apparent to those skilled in the art. Will become apparent.

  [0063] The interior of the entire gasifier is lined with silicon carbide, silicon oxide, aluminum oxide, refractory alloys, other ceramics or another material that has similar properties that are stable at high temperatures. Non-volatile and non-gasified materials are separated from the generator gas by gravity as such materials fall to the bottom of the gasifier. Such a high efficiency gasifier converts the chemical potential energy of the feedstock into generator gas, and the average amount of biochar produced is approximately 1% to 10% of the weight of the original feedstock. %.

  [0064] FIGS. 3 and 4 show a front and side view of the outside of the gasifier. The feedstock moves downward in the gasifier when gasification is performed. When the gasifier reaches a stable operating condition (ie, when each zone of the gasifier reaches a stable sustained temperature), a vertical temperature gradient is formed inside the gasifier, The feedstock is layered into a series of layers or zones that roughly correspond to pyrolysis zone 20, oxidation zone 30 and reduction zone 40 based on the steps in the gasification process. There are no fixed boundaries between these areas, but instead the boundaries are unbroken. Thus, there is a transient gradient with the mixed characteristics of each adjacent zone (ie, feedstock pyrolysis begins in the drying zone 10 and oxidation may begin in the pyrolysis zone 20). The feedstock is maintained at a level above the pyrolysis zone 20 and pulled downward by gravity through the pyrolysis zone 20 so that the descending feedstock replaces the gasified feedstock. Gas and feedstock flow downward in the gasifier. Solid material flows through the gasifier by gravity. The gas moves downward in the gasifier due to the pressure difference.

  [0065] The solids (eg, feedstock and biochar) are vertically adjustable that are located directly below the reduction section 40 of the gasifier as shown in FIGS. 1, 2, 3 and 4 It is held inside the gasifier by a rotary grate 50. The residence time of the solid in the gasifier is governed by the rotational speed of the grate 50, the vertical position of the grate 50 and the speed of gasification (i.e. phase change) in the gasifier. The biochar accumulates at the top of the grate 50 and acts as a sham seal for the bottom of the gasifier, which in turn allows the gasifier to pressurize, Pressurization can be maintained even when leaving the gasifier continuously. Biochar falls from the bottom of the gasifier through a rotating grate 50 or bypass 49. Once biochar falls from grate 50 or bypass 49, biochar falls to one or more collection chutes 60 below grate 50 and then falls to residue box 90, where biochar is augered. 91 is removed from the gasifier.

  [0066] In one embodiment, the areas of the gasifier include a drying section 10, a pyrolysis section 20, an oxidation section 30, a reduction section 40, and comprises a grate 50 disposed below the gasifier. . Below the gasifier are a gas collection vent 70, a biochar collection chute 60, and a biochar residue box 90.

  [0067] FIGS. 5 and 6 show a cut-out front view and a side view that are sized.

[0068] Drying area (optional)
[0069] Overall description, size and function
[0070] In the drying zone 10, moisture in the feedstock evaporates as it is exposed to radiant heat released from the oxidation zone 30. The steam flows down through the pyrolysis zone 20 toward the oxidation zone 30 with the bed oxidant stream and purge oxidant stream fed into the gasifier. The temperature in the drying zone 10 can vary over a very wide range depending on how the gasifier is operated. As an example, for a wood chip having a moisture content of 25%, a typical temperature range in the drying zone 10 is approximately 100 to 300 degrees Fahrenheit. The depth of the drying zone 10 in one embodiment may be from zero to six feet long. This depth may increase with the moisture content of the feedstock, the size of the gasifier and the embodiment of the gasifier used. Radiant heat from the oxidation zone 30 advances this evaporation process. However, preheating of the bed oxidant stream and the purge oxidant stream can accelerate the drying process.

  [0071] The drying operation of the feedstock inside the gasifier is an endothermic process, so that energy (ie heat) is required to dry the feedstock and release water as steam, this steam Helps the reactions that take place below. The wetter the feed, the more energy the drying zone 10 requires.

[0072] The main physical changes in the dry zone 10 are:
[0073] H2O (l) + heat → Η2O (g)
[0074] “H” is hydrogen, “O” is oxygen, “l” is liquid, and “g” is gas.

[0075] Description of feed mechanism and fill level indicator
[0076] As the gasifier is pressurized during operation, a pressure lock is used to feed the feed into the gasifier while maintaining the gasifier pressure. The top valve of the pressure lock is opened, allowing the feed to enter the pressure lock and then closing. The interior of the pressure lock is pressurized to match the air pressure in the pyrolysis zone 20 (or optionally the drying zone 10), which opens the bottom valve so that the feed leaves the pressure lock and adjusts the air pressure. It may be managed by the user through the control system until it is possible to enter the gasifier.

  [0077] The pressure lock may be made from materials such as Schedule 40 seamless carbon steel tubing, 150 pound class steel flanges and standard 150 pound class slide gate valves, such as knife gate valves. This pressure lock assembly is built into the facility design and a pair of standard industrial knife gate valves can be used with the piping between these valves. The piping in one embodiment may be a vertically oriented 18 inch schedule 40 piping. The length of the tubing can be adjusted depending on the feed delivery method and the desired volume. An example of a pressure lock is 72 inches long, which provides 100 to 120 pounds of feed per feed emptied to the drying zone 10 (if applicable) or pyrolysis zone 20 become. In one embodiment, the piping includes (1) a level switch, such as a rotational level switch, limit switch, photon switch or laser switch, and (2) a pressure transmitter and (3) a threaded fitting to receive a pressurized air supply line Is installed.

  [0078] The end user automates the gasifier feedstock filling process with a timer or by using a microwave sensor or another suitable fill level indicator, thereby allowing the gasifier and also the pressure lock (" The presence of the feed at the filling level in the filling level indicator ")" can be detected. The drying section 10 of the gasifier may have one or more fill level indicators 12 that can function in a high temperature environment. Once the fill level indicator 12 detects that the feed level is low, the automatic feed mechanism is started. The design of the gasifier with multiple fill level indicators 12 allows for more options in selecting the feed bed height when utilizing an automatic fill system.

  [0079] In one embodiment, the top valve of the pressure lock opens and the bucket load mechanism empties the feedstock to the pressure lock until the fill level indicator in the pressure lock detects that it is full. The top valve of the pressure lock closes and the pressure lock pressurizes to match the pressure in the drying zone 10 (if applicable) or pyrolysis zone 20. Thereafter, the pressure lock bottom valve opens and deposits the feed on a pressure auger connected to the drying zone 10 (if applicable) or pyrolysis zone 20. The auger then deposits the feedstock on top of the gasifier. The gasifier control system determines when to activate each feedstock charge cycle based on signals such as temperature or pressure changes received from various sensors or indicators in the gasifier.

[0080] Pyrolysis zone
[0081] Comprehensive size and function
[0082] The pyrolysis zone 20 is directly below the drying zone 10 (if the drying zone 10 is included) in the gasifier. The pyrolysis zone 20 may increase or decrease in height based on the most numerous types of characteristics of the expected feedstock. The higher pyrolysis zone 20 accommodates wetter and / or more complex materials that require more drying action and longer pyrolysis times.

  [0083] In the pyrolysis zone 20, steam, oil and constituent gases are distilled and move downwards due to gravity, pressure differences and the action of steam occurring in the drying zone 10 and pyrolysis zone 20. The pyrolysis zone 20 is endothermic at the top and relies on heat released from downstream. Towards the bottom of the pyrolysis zone 20, the temperature increases here, but the feedstock begins to decompose alone because it becomes chemically unstable at the elevated temperature. Thus, the feedstock decomposition occurring in the lower section of the pyrolysis zone 20 is exothermic and releases heat. In one embodiment, pyrolysis zone 20 is 4 to 6 feet deep.

[0084] Pyrolysis chemistry is extremely complex. The most important chemical and physical changes that occur in such areas can be simplified and represented as follows.
[0085] CxHyOz (s) + heat → organic vapor (formaldehyde, alcohol, tar, etc.)
[0086] CxHyOz (s) → CH 4 + H 2 + C (s) + organic vapor (tar) + heat

  [0087] Because some oxygen from the oxidant stream fed to the gasifier is present in the pyrolysis zone 20, oxidation can occur as the feedstock approaches the bottom of the pyrolysis zone 20. There is.

[0088] oxidation zone
[0089] Comprehensive description, size and function
[0090] Oxidation zone 30 is a zone within the gasifier that leads to or away from oxidation zone 350, or is a general step of the method that includes the formation of oxidation zone 350. The oxidation zone 30 is where the oxidation zone 350 is formed and represents the hottest step in the gasification process, where some of the cellulose derivative of the feedstock is converted from solid to gas.

[0091] First slope (induced feedstock slope)
[0092] The flow of the oxidant stream through the active pyrolysis zone 20 shown in FIGS. 7 and 8 begins (1) in a vertical direction toward the top of the outer wall of the pyrolysis zone 20 and the oxidation zone 30 And (2) horizontally, starting at the center of the gasifier and ending at the wall of the gasifier ("induced feed slope"). Induction of the feedstock gradient to form.

  [0093] As shown in FIGS. 7, 8, 9 and 10, the gradient of such induced feedstock is directed toward the perimeter of the gasifier wall and above the oxidation zone 350 ( “The most dense part”) is an increasing feed density density difference that becomes denser and has at least four factors that work together: (1) an oxidation zone that presses the feed against the inner wall of the gasifier Pressure waves from oxidation zone 350, (2) geometry of pyrolysis zone 20 and oxidation zone 30 (ie, wall angle), (3) total volume of oxidant stream flowing into pyrolysis zone 20 and oxidation zone 30, And (4) formed by the relative volumes of oxidant streams flowing into the pyrolysis zone 20 and the oxidation zone 30 respectively. The most dense portion of the induced feedstock gradient is indicated at 200.

  [0094] The feedstock proceeds through the gasifier at different rates. Some of the feedstock may steadily progress down the gasifier in the gasifier flow lane 203, while other feedstocks may pause or decelerate at various points in the gasifier. is there. The feed moves more slowly and / or pauses in the induced feed ramp 200. The most dense portion of the induced feedstock ramp 200 is the feedstock that is denser and moves more slowly than the feedstock in the gasifier flow lane.

  [0095] The densest portion of the induced feedstock ramp 200 terminates in a lower planar air inlet 32 where the oxidation zone 30 extends to a wider diameter. In one embodiment, this extension is designed to be a Kline-Fogelman stage to guide and manage the flow rates of gases and solids moving down the gasifier.

  [0096] Normally, vortices are formed when a gas crosses a particular stage, such as a Kline-Fogelman stage. The lower ring of the planar air inlet 32 in the oxidation zone 30 injects air where otherwise vortices will be formed. Such an incoming air stream collides with the feed gas entering the generator gas and gasifier flow lane 203 down, reinducing the hot gas away from the gasifier wall, creating vortex formation. Hinder and refuel the oxidation zone 350.

  [0097] As conditions in the gasifier change, the induced feedstock gradient also allows for movement of the oxidation zone 350 and gasifier flow lane 203 within the gasifier. This is not possible with other gasifiers where the gasifier flow lane 203 is formed against an outer wall of the gasifier that does not move.

[0098] Oxidation zone
[0099] The feedstock in the gasifier flow lane 203 shown in FIGS. 9 and 10 travels down to enter the oxidation zone 350 through the gasifier. Oxidation zone 350 is a point where significant heat is released by deflagration of the cellulose derivative material in the feedstock. Once started at startup, the oxidation zone 350 is maintained by an additional oxidant stream from the planar air inlets 31, 32 and the feedstock descending from above. Oxidation zone 350 oxidizes a portion of the feedstock to a constituent gas of biochar and generator gas. Tar steam produced in the pyrolysis zone 20 is further broken down into additional generator gas in the presence of steam under the high temperature of the oxidation zone 350.

  [00100] As shown in FIGS. 7, 8, 9 and 10, the overall shape of the oxidation zone 30 is a hollow tube, which is approximately the same size, but unfolded in the center 302. The inlet 301 and the outlet 303 are provided. This is the opposite of conventional downflow gasifiers where the oxidation zone is narrowed to a limit point according to superficial velocity theory.

  [00101] In one embodiment, the inlet 301 and outlet 303 of the oxidation zone 30 are half the diameter of the expanded section of the oxidation zone 30. There are at least two rings of planar air inlets 31, 32. In one embodiment, the higher ring 31 is approximately 11 inches above the lower ring 32 and the lower ring of the planar air inlet 32 is at the widest portion of the expanded section 302 of the oxidation zone 30.

  [00102] The extremely high temperature generated by such an oxidation zone 350 creates heat that advances chemical and physical reactions in the pyrolysis zone 20 and the drying zone 10 above (if applicable). Oxidation zone 350 originally tends to move upward in the gasifier towards the unconsumed feed and the upper oxidant stream source. Below the oxidation zone 350 is a mixture of biochar, which is relatively stable at high temperatures. The gasifier is designed such that the oxidation zone 350 can move up and down in the gasifier. In one embodiment, the oxidation zone 350 is positioned below the grate 50 (under the reduction zone 40) to remove biochar under the oxidation zone 350 so as to suppress the tendency of the oxidation zone 350 to move upward. ) And is held in a predetermined place in the gasifier. Each time the grate 50 rotates, the oxidation zone 350 begins to rise.

  [00103] In one embodiment, the higher ring of the planar air inlet 31 positioned above the lower set of planar air inlets 32 supplies the additional oxidant stream just before the feed enters the oxidation zone 350. It becomes possible to inject the raw material. Utilizing the rotational speed of the grate 50, bed oxidant stream, purge oxidant stream and mobile oxidant stream speeds and ratios, the oxidation zone 350 can be held in any desired location within the gasifier. . In one embodiment, the oxidation zone 350 is maintained just below the planar air inlet 32.

[00104] Partial oxidation of the feedstock is also complex but can be simplified to the following equation:
[00105] Feedstock-Range C + 1 / 2O2-> CO + Heat
[00106] Feedstock-Range C + O2-> CO2 + Heat
[00107] Feedstock-Range H + O2-> H2O + Heat
[00108] Feedstock-Range H → H2
[00109] CO + 3H2-> CH4 + H2O + heat
[00110] CO2 + 4H2 → CH4 + 2H2O + heat
[00111] Solid C residue + 2H2 → CH4 + heat
[00112] CO + H2O → C02 + H2 + heat

  [00113] The reaction in the oxidation zone 30 is exothermic and releases heat to operate the entire gasifier.

[00114] Second slope (inclined biochar slope)
[00115] As shown in FIGS. 7, 8, 9, and 10, immediately below the oxidation zone 350, the beginning of the second biochar slope is (1) vertically within the oxidation zone 30. Starting directly below the lower ring of the planar air inlet 32 and extending down the reduction zone 40 along the walls of the oxidation zone 30 and (2) horizontally from the center of the gasifier to the wall of the gasifier ( "Inclined biochar") formed. As biochar leaves the oxidation zone 350, the diameter of the oxidation zone 30 narrows to approximately the same size as the inlet 301 to the oxidation zone 30. Pressure waves from the oxidation zone press the biochar against the narrowing wall of the oxidation zone. The most dense part of the inflowing biochar slope is shown at 300. The pressure wave slows the movement of the densest portion of the biochar slope 300 that flows into the gasifier flow lane 203 relative to the biochar. The gasifier flow lane 203 remains as it is even if the feedstock changes phase, and here the generator gas and biochar move downward instead of the feedstock.

  [00116] The densest portion of the inflowing biochar slope 300 extends down the reduction zone 40 along the walls of the oxidation zone 30. Since the reduction zone 40 is wider than the oxidation zone 30, the entrance to the reduction zone 40 forms a separate process. In one embodiment, the angled walls of the oxidation zone 30 and the entrance to the reduction zone 40 form a Kline-Fogleman stage. As the generator gas crosses this stage and enters a larger reduction zone 40 (ie, a diameter extension in the reduction zone 40), a vortex is formed in the reduction zone 40. This vortex facilitates the mixing action of the generator gas and biochar in the reduction zone 40.

[00117] Simulation of hearth and hearth
[00118] Unlike conventional downflow gasifiers, this downflow gasifier does not have a restricted area within the oxidation zone 30, but instead the oxidation zone 30 increases in size. Almost all downflow gasifiers are constructed with a restriction in the oxidation zone 30 in order to apply superficial velocity theory and thus achieve a quality generator gas that can be used. In addition, most downflow gasifiers utilize vacuum to draw the generator gas through the gasifier.

  [00119] The two slopes formed in such a gasifier, namely, the slope of the induced feedstock above the oxidation zone 350 and the slope of the incoming biochar below the oxidation zone 350 cooperate. To simulate the furnace top and hearth inside the gasifier. The advantage of this approach is that the oxidation zone 350 can be moved up and down in the gasifier without damaging or possibly destroying the gasifier itself, and within the gasifier, different types of A feedstock and a mixture of feedstocks can be employed. Other gasifiers with a fixed hearth and hearth need to be calibrated for a narrow range of feedstock and can be easily adjusted to accommodate other types of feedstock. Neither can it be adjusted during operation to accommodate changes.

[00120] Reduction area
[00121] Comprehensive description, size and function
[00122] As shown in FIGS. 1, 2, 7, and 8, the reduction zone 40 of the gasifier is of a diameter equal to or greater than the outlet 303 of the oxidation zone 30. The two main functions of the reduction zone 40 are to gasify the remaining carbon from the biochar and cool the generator gas. Both of these functions occur by the same mechanism, ie, an endothermic reaction between the reactor gas components and the solid carbon contained in the biochar.

  [00123] As discussed above, turbulent flow across the stage between the outlet 303 of the oxidation zone 30 and the wider reduction zone 40 as the generator gas and biochar enter the reduction zone 40 The vortex is formed. This turbulence in the reduction zone 40 results in a reactor gas and biochar mixing effect in the reduction zone 40 that is far superior to other gasifier designs. This allows nearly perfect gasification of the carbon in the bed and maximizes the cooling effect. In one embodiment, the reduction zone 40 of the gasifier maintains a bed of approximately 2 to 6 feet of biochar above the grate 50.

  [00124] The generator gas exits a typical downflow gasifier at a temperature around 1500 degrees Fahrenheit. The generator gas exits the gasifier at a temperature of less than 1500 ° Fahrenheit. In one embodiment, the generator gas leaves at less than 1000 degrees Fahrenheit. Also, a thick bio-char bed allows approximately 90 to 99% of the fuel carbon to exit the gasifier as the generator gas, depending on the feedstock.

[00125] The reduction reactions occurring in downflow gasifiers are well studied and are understood to involve the following.
[00126] Carbon + CO2 + heat → 2CO
[00127] carbon + H2O + heat → CO + H2
[00128] carbon + 2H2O + heat → CO2 + 2H2
[00129] CO2 + H2 + heat → CO + H2O

[00130] gasifier grate
[00131] The grate 50 of the gasifier is another suitable such as stainless steel or silicon carbide, silicon oxide, aluminum oxide, heat resistant alloys, other ceramics that are durable and heat resistant and not heat sensitive. The grate may be made of a material, and the grate has a top surface and a bottom surface. In one embodiment, and as shown in FIGS. 3 and 4, the grate bottom face and shaft move up and down and are installed on a rising platform 80 managed by an adjustable control system. Good. As shown in FIGS. 3 and 4, the top surface of the grate 50 is located below the lower edge of the reduction zone 40. In one embodiment, the bypass is a 2.5 to 2 inch gap between the reduction zone 40 and the top face of the grate 50.

[00132] spiral groove
[00133] FIG. 11 shows a gasifier grate 50 that provides support for all of the solids in the gasifier. In one embodiment, the grate 50 has a frame 505 and two surfaces: a top surface and a bottom surface.

  [00134] FIGS. 11 and 12 show the top surface of a grate 50 having a helical groove 501. FIG. The helical groove 501 is oriented in the gasifier so that this groove faces the reduction zone 40. The helical groove 501 has a starting point at the center of the grate and a distal end that continues outward with respect to the edge of the grate 50. Thus, in one embodiment, the helical groove extends across the top surface of the grate. The purpose of the spiral groove 501 is that when the grate 50 is originally rotated opposite to the direction of the spiral groove 501, the bio charcoal is moved outward from the center of the grate 50 to the edge of the grate 50 It is to move toward. The biochar follows the end of the helical groove 501 until the biochar is pushed out of the reduction zone 40 through the bypass as the grate 50 rotates in the opposite direction.

  [00135] In one embodiment of the reduction zone 40, silicon carbide, silicon oxide, aluminum oxide, refractory alloys, other ceramics, or any other refractory, dense layer material lining the walls of the reduction zone 40 To do. This refractory, dense layer material acts as a file to constantly crush any biochar that is pressed against the outer wall of the reduction zone 40 by the rotating grate 50 and dragged along the outer wall. Such a combination having a spiral groove 50 in the grate and pushing biochar toward and along the layer wall of the reduction zone 40 is a sufficiently small fragment to escape large chunks of carbide to the bypass. To help crush. One skilled in the art will appreciate that different types of helices (eg, Archimedean principle, logarithmic, etc.) can be used.

  [00136] In one embodiment, the spiral groove 501 in the grate is a "v" -shaped Archimedean principle groove 502, where the outer edge of one groove in the helix is adjacent to the adjacent groove. A raised edge is formed together with the inner edge. The purpose of the “v” shaped groove is to avoid having any 90 ° angle, which would otherwise avoid hot spots or thermally unstable sections of the grate 50. Will form.

[00137] Grate / Bypass Lift
[00138] In one embodiment, the grate 50 can be raised and lowered to form a higher or lower bypass, larger material and / or not gasified unintentionally entering the gasifier Substances can be removed without stopping the gasifier (brick blocks, stones, etc.). In one embodiment with a spiral groove 501 in the grate 50, such foreign matter is pushed against the walls of the reduction zone 40 so that these foreign matter can then be discharged via a bypass. The grate 50 can be lowered. Such a design allows the gasifier to be kept in use and even removes large non-gasified objects from the reduction zone 40. The ability to raise and lower the grate 50 can also be utilized when maintenance is constantly required inside the gasifier. In addition, the bypass 49 functions to control the flow of generator gas exiting the reduction zone 40, and the bypass 49 acts like a valve. For example, a short bypass increases resistance to the flow of generator gas through the grate 50 and allows the pressure to increase in the gasifier.

[00139] Oval hole in grate
[00140] FIGS. 13 and 14 show the grate after assembly. 15 and 16 illustrate a “pie slice” segment 502 of a grate. 13 and 14 show a perspective view and a front view of the assembled grate having an oval hole 503. FIG. In one embodiment, the oval holes 503 are, for example, kidney-shaped or oval holes that are symmetrically distributed throughout the grate 50 (but above the mechanical axis that lifts and rotates the grate). There is no hole in the center of the grate). The purpose of the hole 503 is to allow both biochar and generator gas to pass through the grate and enter the biochar collection chute 60 below it.

[00141] Pie slice inserts for grate
[00142] In one embodiment, "pie slices" segments 502, 504 are placed on a frame 505 of a grate 50. As each of the segments 504 is inserted into the frame 505, a grate is formed. This embodiment allows the segment 504 to be replaced instead of the entire grate 50 if a portion of the grate 50 is damaged, and the gasifier is designed for a particular type of feedstock. It can also be adapted with customized segments 504.

[00143] Grate with multiple features
[00144] FIG. 15 is a perspective view of the removable portion of the grate. In one embodiment, the grate 50 also has a helical groove 501 cut out as a “v” shape 502 and a kidney-shaped or oval hole 503 that cuts through the helical groove 501. FIG. 16 shows a top view of the removable part of the grate.

[00145] Control of gasifier using grate
[00146] The shaft that supports and rotates the grate 50 may be formed of one or more parts depending on the size of the grate 50. The rotational speed of the grate 50 can be calibrated by the control system, but typically ranges from 0.0001 RPM to 1 RPM, depending on the non-volatile components of the feedstock and the generation rate of the reactor gas. Oxidation zone 350 is effectively on top of the biochar bed in reduction zone 40, so if the biochar bed in reduction zone 40 becomes too thick, oxidation zone 350 will be in pyrolysis zone 20. Will rise to enter. By monitoring the location of the oxidation zone 350 using a thermocouple or other sensor, the gasifier control system discussed below increases the speed of rotation of the grate 50 and produces biochar at higher speeds. Can be programmed to remove, thereby lowering the height of the biochar bed and lowering the oxidation zone 350 back to the proper location. Conversely, the control system of the gasifier can slow down the grate 50 if the biochar bed becomes too shallow, resulting in the oxidation zone 350 moving too close to the grate.

[00147] Carbide collecting chute
[00148] Below the gasifier is a biochar collection chute 60, as shown in FIGS. 1, 2, 5 and 6, which is steel, stainless steel or another rugged, heat stable May be made of a material that is free of pores. As biochar exits from the bottom or side of the grate 50, the biochar falls down to a biochar collection chute 60 below the gasifier. The biochar collection chute 60 is positioned at a specific angle from the direction of biochar flow in the gasifier flow lane 203. In one embodiment, this angle is less than 90 ° as measured from the direction of biochar flow in the gasifier flow lane 203. In one embodiment, this angle is between 45 ° and 80 ° as measured from the direction of biochar flow in the gasifier flow lane 203. In one embodiment, at least two biochar collection chutes 60 are arranged symmetrically with respect to the central axis of the gasifier.

[00149] Generator gas collection vent / horn
[00150] As shown in FIGS. 1, 2, 5, and 6, the biochar collection chute 60 such that two or more generator gas collection vents 70 are symmetrical about the axis of the grate 50. Placed inside. The opening to the generator gas collection vent 70 faces downward so that biochar does not fall directly into these vents as it falls from the grate 50. As the generator gas and biochar fall into the biochar collection chute 60, the biochar is separated from the generator gas by gravity, and the generator gas exits through the generator gas collection vent 70.

[00151] Bio charcoal residue box
[00152] A biochar residue box 90 is at the bottom of the biochar collection chute 60, as shown in FIG. The biochar falls down the biochar collection chute 60 and enters the biochar residue box 90.

  [00153] The biochar residue box has a tube type auger 91 called "residue auger". The residue auger 91 moves the biochar to enter the pocket valve 92 bolted to the end of the cross-shaped spool pipe bolted to the residue auger 91. In one embodiment, pocket valve 92 is a standard air-initiated 8 inch or 10 inch ball valve, where the ball valve is sealed at one end. In the “up” position, the ball forms a bucket. Since the residue auger 91 is controlled by the control system of the gasifier, the residue auger 91 deposits biochar into the pocket valve 92 when the pocket valve 92 is in the up position. When the control system stops this process, the residue auger 91 stops and the pocket valve 92 rotates to the “down” position and its contents are removed to an external collection box or some other secondary removal system. Free. Since the ball in the pocket valve 92 is closed at one end, the pocket valve 92 is always sealed and prevents the reactor gas from leaking out of the biochar residue box 90. A small amount of generated furnace gas leaks, but can be safely vented by a high-priced vent line or sucked out by a vacuum pump.

[00154] Feedstock requirements
[00155] The gasifier can gasify a very wide range of feedstocks. In order to determine whether a given feedstock or mixture of materials effectively gasifies, the feedstock is sufficiently porous and suitable to allow the oxidant stream to pass through the feedstock. Heat generation density (btu / ft3), suitable bulk density and suitable chemical composition. Those skilled in the art will recognize suitable feedstocks. In one embodiment of the gasifier, suitable feedstocks are: (1) 25% or more chemically bonded oxygen content (molecular basis), (2) 10% or less ash content, (3) 30 % Moisture content and (4) bulk density greater than 15 lbs / ft3. There is some interaction between these variables.

  [00156] All biomass forms contain the basic chemical structure of CxHyOz. This molecular structure is inherently unstable at elevated temperatures and easily decomposes when heated. This is the basic driver for all types of biomass gasifiers. This molecular degradation is highly exothermic and produces the heat necessary to sustain further biomass degradation. Thus, in practice all forms of biomass are suitable feedstocks for gasifiers provided they meet the porosity and bulk density requirements.

[00157] Start and stop
[00158] At start-up, the gasifier is filled with feed to the middle of the oxidation zone 30. A layer of hot charcoal (in one embodiment, a few inches tall) is applied to the top of the feedstock through the top of the pyrolysis zone 20 or drying zone 10 (if applicable). The gasifier is then filled with the feedstock and the gasifier level indicator and the gasifier control system are started.

  [00159] Over the next few hours, the gasifier begins to heat up and a temperature gradient begins to form. Some low quality gas is formed almost immediately and the generator gas production gradually increases and improves as the gasifier heats.

  [00160] If the gasifier is operated for an appropriate period of time, the lining inside the gasifier will contain plenty of heat and the gasifier will add even after a few hours of downtime. Can be restarted without high temperature charcoal. This is called a “warm start”. In many cases, the gasifier can maintain sufficient internal heat for a warm start by simply re-initiating the oxidant stream, even if shut down for more than 2 to 3 days. The generator gas flow from the gasifier stops when the oxidant stream stops.

[00161] Gasifier control system
[00162] Optimization of gasifier operation requires precise real-time adjustments to manage the location of the oxidation zone 350. For example, if a mechanical device is inserted into the oxidation zone 350 to adjust the speed of the material that leaves or enters, the temperature of 3000 degrees Fahrenheit in the oxidation zone 350 (approximate) Will destroy. Thus, the grate 50 can be placed adjacent to the much cooler reduction zone 40, so the grate 50 is used to manage the removal of biochar from the gasifier. The change in the height of the biochar bed caused by increasing the removal rate of biochar from the reduction zone 40 induces any changes necessary to adjust the vertical position of the oxidation zone 350. Each of the variables mentioned below can be adjusted to induce changes in the oxidation zone 350.

  [00163] Utilizing multiple methods and systems as part of the overall control system can induce changes and control the oxidation zone 350. The control system uses various algorithms to monitor and adjust the gasifier. The control system can include subsystems that can be adjusted in real time and can describe other methods that can only be adjusted while the gasifier is offline. Adjustments while the gasifier is taken offline include (1) adjusting the physical size and height of the drying area 10 (or removing the drying area 10), and (2) adjusting the size of the holes 503 in the grate 50. Adjustments (in one embodiment, by exchanging compatible segments 504 of grate 50) may be included. The control system includes (a) the type of feedstock entering the gasifier, (b) the rate at which the feedstock enters the gasifier, (c) the charge level of the feedstock in the drying zone 10 when applicable, (D) the temperature of the drying zone 10 when applicable, (e) the volume, velocity and pressure of the oxidant stream delivered via the inlet at the top of the pyrolysis zone 20 (or drying zone 10 if applicable). (F) volume, velocity and pressure of the oxidant stream delivered through the ring of the planar air inlets 31, 32, (g) the overall pressure of the gasifier, (h) in various areas of the gasifier Pressure difference, (i) location of oxidation zone 350 in the gasifier, (j) adjustment of grate 50 rotational speed, (k) vertical position of grate 50 (ie adjustment of bypass height) (L) Reduction zone 4 The thickness of the bio-charcoal bed in (m) testing and sampling of the components of the generator gas leaving the gasifier, (n) the temperature of the generator gas leaving the gasifier, (o) the generator Includes subsystems to perform real-time adjustments during operation of the gasifier with respect to the pressure of the gas collection vent and the pressure of the generator gas exiting the gasifier (the example above is “variable”) Can do.

[00164] Variable frequency drive
[00165] In one embodiment of the gasifier, the control system can gradually increase or decrease a particular variable, or initiate or stop any change to the entire variable. For example, the control system may need to slightly slow the rotational speed of the grate 50 at one point and then need to completely stop the grate 50 at another point. Those skilled in the art will operate in two general ways where the electric motor and drive are partly fixed speed drive and the other is a variable frequency (speed) drive ("VFD"). You will understand what to do. In one embodiment of the gasifier, the VFD is thus mounted on an on / off timer and used to control the rotational speed of the grate 50. By starting and stopping the VFD, the control system can simulate the rotation of the slow grate 50 while maintaining sufficient torque from the VFD to rotate the grate 50.

  [00166] In other applications, such as oxidant stream control systems where higher torque is not required, the VFD may be utilized without an on / off timer.

[00167] Grate management
[00168] The control system adjusts a plurality of variables, including a pressure difference between the oxidation zone 30 and the reduction zone 40, by adjusting the rotational speed of the grate 50. An example of this latter is that the pressure difference in the reduction zone can be maintained simply by managing the grate 50 RPM settings.

[00169] Oxidant stream flow control
[00170] The speed at which biochar exits the gasifier also controls the vertical pressure differential across the gasifier (though the thickness of the biochar bed determines the gasifier pressure to some extent, This is because biochar forms a fake seal at the bottom of the gasifier). The vertical pressure differential across the gasifier, i.e. the pressure passing through the top of the drying zone 10 through the bottom of the grate 50, thus simply increases or decreases the rotational speed of the grate 50, thereby discharging biochar from the reduction zone 40. To some extent. Stated another way, if biochar is not discharged from the gasifier at a sufficient rate, biochar will accumulate in the reduction zone 40 and a reduced remaining volume will be generated in the reduction zone 40 and oxidation zone 30. Increase furnace gas pressure. In one embodiment, the vertical pressure differential of the gasifier is controlled by the height of the bypass, and as the bypass height increases (ie, by lowering the grate 50), the generator from the gasifier The flow of gas and biochar increases.

  [00171] The rate of generation of the generator gas is proportional to the concentration of oxygen in the oxidant stream and the flow rate of the oxidant stream input to the gasifier. The control system measures and regulates the oxidant stream using standard methods known in the art.

  [00172] FIG. 17 is a cutaway side view of the gasifier with arrows depicting the gasification process. Three types of oxidant streams, namely purge oxidant stream, bed oxidant stream and piano oxidant stream, enter the gasifier through three separate corresponding entry points. The purge oxidant stream is the oxidant stream that is charged to the feed and enters the gasifier with the feed via a pressure lock. The purge oxidant stream also prevents stagnant gas from backflow to the pressure lock. The bed oxidant stream enters the gasifier through an inlet 11 located at the top of the gasifier. The planar oxidant stream enters the gasifier through planar air inlets 31, 32 disposed in the ring around the periphery of the oxidation zone 30. A control system monitors and regulates each such oxidant stream to manage the total amount of oxygen and the amount of generated reactor gas in each zone of the gasifier. The control system adjusts the volume and velocity of such oxidant streams to adjust to feeds with different moisture content, bulk density, or even because the BTU value of the feedstock changes. Can be adjusted. The control system allows changes to be made while the gasifier is activated so that it is not necessary to shut down or reconfigure the gasifier.

  [00173] The more oxygen supplied to the gasifier, the faster the feedstock is gasified in the oxidation zone. As the reaction is accelerated, more biochar is produced and accumulated in the reduction zone 40.

  [00174] Implementation of a control system aimed at variable control of the grate 50 and oxidant stream in the gasifier also ensures the concentration and quality of the generator gas.

[00175] Thermocouple and ceramic lining
[00176] A plurality of different overlapping control methods are used in the gasifier, and most function as a means by which more accurate control can be achieved throughout the process. In one embodiment, an effective control method is to monitor the thermal gradient or thermal profile indicated by the temperature of each zone. Such a temperature is obtained by a thermocouple embedded inside the lined wall of the gasifier. This temperature gradient or thermal profile is a very good indication of where each zone is and where each zone moves within the gasifier. In one embodiment, the control system uses this information to change the balance of the oxidant stream in any given zone, or to change the biochar bed in the reduction zone 40 via rotation and bypass of the grate 50. Physically changing the height helps to maintain and / or sustain each area above it.

  [00177] Certain embodiments improve the concentration of the generator gas by lining the entire gasifier with silicon carbide, silicon oxide, aluminum oxide, refractory alloys, other ceramics, or another material that is stable at high temperatures. To do. Such a lining helps to disperse and conduct the heat exiting the oxidation zone 350 evenly and allows the thermocouple to be utilized while protecting the thermocouple from reactions occurring inside the gasifier. .

  [00178] The control system can utilize all different methods and incorporate the methods into the controller for the algorithm. The latter not only allows for redundancy throughout the control system, but also ensures greater reliability and efficiency. It further ensures that the generated furnace gas is constant and of high quality.

  [00179] The gasifier applications and methods described above also provide an effective way of managing the height of the reduction zone 40. A problem with other gasifiers is that the oxidation zone 350 is limited to one location within the gasifier, and moving the oxidation zone 350 substantially interferes with the function of the process or destroys the gasifier. Is to be. In one embodiment of this gasifier, the oxidation zone 350 can be moved up into the pyrolysis zone 20 or down into the reduction zone 40, yet the oxidant stream is placed by the control system. The oxidation zone can be managed and / or maintained by allowing a certain amount of biochar to be removed. This allows the feed height collapse or pressure differential across the gasifier to be managed through the rotation of the grate 50 without the risk of crushing the oxidation zone 350.

[00180] Gas produced
[00181] During operation, the gasifier forms a generator gas having a heat generation density of 125 to 145 btu / ft3. Such generator gas quality is continuously produced as long as sufficient oxidant stream and suitable feedstock are available to the gasifier. In one embodiment, the gasifier converts 12 to 120 tons of feedstock per day.

  [00182] This gasifier is very different in design from other gasifiers, and the overall process for the output and quality of the reactor gas and other downflow gasifiers on the market today. It is clear that the efficiency of the system is considerably improved.

[00183] Multi-faceted matters
[00184] All references, including publications, patent applications, and patents cited herein, are pointed out as if each reference was individually and specifically incorporated by reference, in its entirety. Incorporated herein by reference to the same extent as described herein.

  [00185] The terms "a" and "an" and "the" and like indicating terms in the context of describing the invention are singular unless otherwise indicated herein or otherwise clearly contradicted by context. And should be interpreted to encompass both. The terms “comprising”, “having”, “including” and “containing” should be interpreted as open terms unless otherwise indicated. Yes (ie “include but not limit”). The recitation of a range as a value herein is merely intended to serve as a simple way to individually point to each individual value within the range, unless otherwise indicated herein. Each individual value is incorporated into the specification as if it were individually described herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. Use of any and all examples or exemplary terms (eg “etc.”) provided herein is merely intended to better elucidate the present invention, and not Does not limit the scope of the invention (i.e., but not limited thereto). No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

  [00186] Preferred embodiments of the invention are described herein. Variations of such preferred embodiments will become apparent to those skilled in the art upon reading the foregoing description. The inventors anticipate that skilled workers will appropriately employ such variations, and that the inventors have implemented the invention in a manner different from that specifically described herein. Is intended to be. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

  [00187] While the foregoing disclosure describes the principles of the present invention in conjunction with examples presented for purposes of illustration only, the use of the present invention is intended to fall within the scope of the appended claims and their equivalents. It should be understood that all normal variations, adaptations and / or modifications are included within the scope of. Those skilled in the art will appreciate from the foregoing that various adaptations and modifications of the embodiments just described can be made without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.

Claims (49)

A plurality of coupled vertically disposed tubes having an inner wall, an outer wall, a proximal end providing an inlet, and a distal end providing an outlet;
At least three successive reaction zones, a pyrolysis zone that is angled towards the central convergence, followed by an oxidation zone, with the central portion of the tube corresponding to the oxidation zone widened At least three successive reaction zones comprising an oxidation zone and a subsequent reduction zone, wherein the inner wall of the tube corresponding to said reduction zone has a reduction zone having a larger diameter than the tube corresponding to said oxidation zone;
At least two rings of planar air inlets arranged in the oxidation zone for injecting air;
A rotary and vertically adjustable grate disposed below the reduction zone but not in contact with the reduction zone;
A gasifier, which is a partially open core downflow gasifier used for feedstock gasification.   The gasifier according to claim 1, further comprising a housing disposed around the outer wall of the plurality of coupled vertically disposed tubes.   The inner wall has a lining made of a material that is stable at a temperature suitable for gasification, and the material is silicon carbide, silicon oxide, aluminum oxide, ceramic or a heat resistant alloy. Gasifier.   The apparatus of claim 1, further comprising a non-planar air inlet, wherein a bed oxidant stream enters the gasifier via the non-planar air inlet, and a purge oxidant stream enters the gasifier along with the feedstock. The gasifier described.   The gasifier of claim 1, wherein the gasifier is pressurized during operation.   The gasifier of claim 1, further comprising an oxidation zone that occurs directly under at least one of the at least two rings of the planar air inlet.   The gasification of claim 6, further comprising a gradient of induced feedstock that occurs above the oxidation zone and a gradient of inflowing biochar that occurs below the oxidation zone during use of the gasifier. apparatus.   The gasifier according to claim 7, wherein a furnace top and hearth gasifier is simulated by the induced feed gradient and the inflow biochar gradient.   The gasifier of claim 1, further comprising a drying zone.   The apparatus of claim 1, further comprising at least one fill level indicator in the pyrolysis zone and an automatic feed mechanism that is triggered when the at least one fill level indicator detects a low feed level. Gasifier.   The gasifier of claim 1, wherein the expanded portion of the tube in the oxidation zone is a Kline-Fogelman stage.   The gasifier of claim 1, further comprising a gasifier flow lane and an oxidation zone in use.   The gasifier of claim 12, wherein the gasifier flow lane changes size within the gasifier and further the oxidation zone moves up and down in the gasifier.   The gasifier of claim 1, wherein at least one of the at least two rings of the planar air inlet is disposed around the unfolded portion of the tube corresponding to the oxidation zone.   The gasifier according to claim 1, wherein the inner wall of the tube corresponding to the reduction zone having a larger diameter than the tube corresponding to the oxidation zone is a Kline-Fogleman stage.   During use of the gasifier, further comprising a biochar bed in the reduction zone directly above the grate, wherein the feedstock and the biochar bed are brought into the gasifier by the grate. The gasifier according to claim 1, which is held.   The gasifier of claim 1, further comprising a bypass between the reduction zone and the grate.   The gasifier of claim 1, further comprising at least one biochar collection chute and a residue box under the grate for collecting biochar falling from the distal end of the gasifier.   The gasifier of claim 18, further comprising two or more generator gas collection vents arranged symmetrically on the at least one biochar collection chute.   The gasifier of claim 1, further comprising at least two biochar collection chutes and a residue box arranged symmetrically with respect to the combined vertically arranged tubes of the gasifier.   The gasifier of claim 1, further comprising a control system for operating the gasifier.   The gasifier of claim 21, wherein the control system adjusts and rotates the grate vertically to manage residence time of the feedstock and biochar in the gasifier.   The gasifier of claim 21, further comprising a sensor that functions to monitor variables in the reaction zone of the gasifier.   The grate has durability, heat resistance and non-reactivity, the grate has a top surface and a bottom surface, and the top surface of the grate is in the vertical direction of the gasifier. The top face of the grate further has a specific pattern that is a spiral groove that starts at the center of the grate and extends over the top face of the grate, without making a right angle to the arranged tube The gasifier according to claim 1.   The biochar from the distal end of the gasifier falls through the grate from the distal end of the gasifier, further comprising holes in the grate and symmetrically distributed throughout the grate. Gasifier.   The grate has a top surface and a bottom surface, the bottom surface of the grate is a frame, and the top surface of the grate comprises a plurality of interchangeable segments that rest on the frame. The gasifier according to 1. Filling a gasifier with a feedstock, wherein the gasifier comprises a plurality of tubes arranged in a vertical orientation, the plurality of tubes providing an inner wall, an outer wall, an inlet, a proximal end Having a distal end providing an outlet, a pyrolysis zone, an oxidation zone, and a reduction zone; and
Igniting the feedstock to form an oxidation zone;
Injecting an oxidant stream into the oxidation zone utilizing at least two rings of a planar air inlet;
A pyrolysis zone where the feedstock begins to fluidize and decompose, an oxidation zone where the feedstock is converted to generator gas, and a reduction zone where the generator gas mixes with biochar and cools to form additional generator gas Moving the feedstock in order to pass through,
Holding a bed of feedstock and biochar within the gasifier utilizing a rotary, vertically adjustable grate disposed under the reduction zone;
Removing biochar and generator gas through a bypass and a hole in the grate;
Refilling the gasifier with a feedstock, and gasifying the feedstock.   28. The inner wall of claim 27, wherein the inner wall has a lining made of a material that is stable at a temperature suitable for gasification, and the material is silicon carbide, silicon oxide, aluminum oxide, ceramic or a heat resistant alloy. Method.   28. The method of claim 27, further comprising injecting air into the gasifier by a non-planar air inlet.   30. The method of claim 29, wherein a bed oxidant stream enters the gasifier through a non-planar air inlet and a purge oxidant stream enters the gasifier with the feed.   28. The method of claim 27, further comprising pressurizing the gasifier during operation.   Through the use of the gasifier, the top and hearth gasifiers are simulated by forming a feedstock gradient induced above the oxidation zone and a biochar slope flowing below the oxidation zone. The tube corresponding to the oxidation zone has a widened central portion followed by a reduction zone, and the inner wall of the tube corresponding to the reduction zone is the oxidation zone. 28. The method of claim 27, having a larger diameter than the tube corresponding to.   35. The method of claim 32, wherein at least one of the at least two rings of the planar air inlet is disposed around the expanded portion of the tube corresponding to the oxidation zone.   At least one of the at least two rings of the planar air inlet is disposed above the planar air inlet disposed around the expanded portion of the tube corresponding to the oxidation zone, thereby providing additional oxidation. 34. The method of claim 33, wherein an agent stream can be injected into the feedstock.   28. The method of claim 27, further comprising mixing a generator gas and biochar in the reduction zone, the step realized by formation of vortices in the reduction zone.   28. The method of claim 27, wherein the grate has durability, heat resistance and non-reactivity.   The grate has a top surface and a bottom surface, the top surface has a center, does not form a right angle to the vertically disposed tube of the gasifier, and the grate 28. The method of claim 27, wherein the method is patterned by a helical groove that begins at the center of the top surface of the grate and extends across the top surface of the grate.   38. The method of claim 37, further comprising holes in the grate and symmetrically distributed throughout the grate.   40. The method of claim 38, wherein the holes in the grate are oval, kidney, or oval.   38. The method of claim 37, wherein the bottom surface of the grate is a frame and further comprises a plurality of interchangeable segments that rest on the frame.   38. The method of claim 37, further comprising rotating the grate in a direction opposite to the spiral groove.   42. further comprising moving biochar from the center of the top face of the grate outward to the grate edge and pushing the biochar out of the reduction zone via a bypass. The method described.   28. The method of claim 27, further comprising removing material that has not been gasified during operation of the gasifier by using a bypass.   28. The method of claim 27, further comprising the step of monitoring and adjusting gasifier variables utilizing a control system and sensors.   The control system variables are (a) feed type, delivery rate and fill level, (b) temperature in the zone, (c) oxidant stream volume, rate and pressure, (d) the gasifier. (E) location of the oxidation zone, (f) vertical position and rotational speed of the grate, (g) removal of biochar, (h) thickness of biochar bed, (i) Including: component testing and sampling and the temperature of the generator gas exiting the gasifier, and (j) the pressure of the generator gas collection vent and the pressure of the generator gas exiting the gasifier, 45. The method of claim 44.   45. The method of claim 44, further comprising maintaining the oxidation zone at any desired location in the gasifier by utilizing the control system and adjusting a removal rate of biochar from the grate. The method described.   Maintaining the oxidation zone at any desired location in the gasifier by utilizing the control system and adjusting the rate and ratio of bed oxidant stream, purge oxidant stream and planar oxidant stream 48. The method of claim 46, further comprising:   45. The method of claim 44, further comprising adjusting a vertical pressure difference across the gasifier according to a rotational speed of the grate and managing a rate at which biochar is discharged from the reduction zone. 28. The method of claim 27, wherein the biochar bed is a sham seal for the distal end of the gasifier.

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