JP2014532096A - Method and system for roasting lignocellulosic material - Google Patents

Abstract

A method for roasting biomass using a roasting reaction vessel having stacked trays, wherein the method is such that the biomass material is deposited on the upper tray of a vertical stack of trays in the reaction vessel. Feeding biomass to the upper inlet of the reactor; sequentially dropping the biomass from the tray by passing the biomass through each opening in the tray and depositing the biomass on the lower tray; a tray on which the biomass is stacked Heating the biomass material with an oxygen-deficient gas injected into the reactor as it travels around each of the gas; the moisture containing gas passing through the biomass on the upper tray Extracting directly below; biomass roasted in the lower tray of the stacked trays Holding the gas with the biomass until it falls from the stacked tray to the biomass deposit in the reaction vessel; the tray containing the organic compound volatilized by roasting of the biomass Extracting from the gas outlet of the reaction vessel at a height between the bottom and the biomass deposit; and discharging the roasted biomass from the lower outlet of the roasting reaction vessel.

Description

Related applications

  This application claims the priority of US Provisional Patent Application No. 61 / 537,413 filed on September 21, 2011 and 61 / 551,932 filed on October 27, 2011. The entire application of which is incorporated herein by reference.

Background of the Invention

  The present invention broadly includes biomass materials such as wood and other lignocellulosic materials, and biomass containing fossil materials such as plastic fractions and waste-derived fuel (RDF) (these materials). Are collectively referred to as “biomass material”). More particularly, the present invention relates to a pressurized reactor for roasting biomass material.

  Roasting is usually performed in an oxygen-deficient atmosphere at a relatively low temperature of 200 degrees Celsius (° C.) to 400 ° C. or 200 ° C. to 350 ° C., a temperature outside the range used in a process known as pyrolysis It refers to the heat treatment of biomass that is performed. The oxygen-deficient atmosphere has a low oxygen proportion compared to the proportion of oxygen in the atmosphere. The roasting process is described in US Patent Application Publication No. 2011/0041392. By roasting, the biomass material is converted into an efficient fuel having an increased energy density compared to the biomass that is input. Roasting removes moisture and volatile components from the biomass material. In roasting, the hemicellulose fraction of the biomass material is largely destroyed to produce moisture and volatile organic compounds (VOC), while the cellulose fraction is depolymerized to yield untreated biomass material. Produces a hydrophobic solid combustible fuel product having a higher energy density (on a mass basis). Furthermore, the roasted biomass material may be pulverized.

  Roasting changes the chemical structure of the biomass. The roasted biomass may be combusted in a coal fired facility (roasted wood or biomass has characteristics similar to those of low grade coal) and may be compressed into high grade fuel pellets.

  As described in U.S. Patent Application Publication No. 2010/0083530 ('530 application), an unpressurized reaction vessel with multiple trays is used for roasting. The '530 application recommends that roasting be carried out in a reactor operated at atmospheric pressure. In view of this recommendation, the '530 application teaches that the reactor should not be operated at pressures above atmospheric pressure. See paragraph 0061 of the '530 application.

  Pressurized reactors with multiple trays are used in pulp mills to delignify pulp by oxidation. Examples of pulping reactors having multiple trays are disclosed in U.S. Pat. No. 3,742,735 (the '735 patent) and U.S. Pat. No. 3,660,225 (the' 225 patent). A reaction vessel having a plurality of trays allows pulp to fall through a vertically arranged tray in the reaction vessel. The tray allows the pulp to fall sequentially in the reaction vessel in individual batches. When the inside of the pulping reaction tank is rich in oxygen, delignification and bleaching of the pulp are promoted. The '735 and' 225 patents do not suggest using a pulping reactor having an oxygen-deficient environment for roasting wood or other biomass material.

Brief description of the invention

  The reaction vessel heats the biomass on each tray so that the biomass is uniformly heated at each height in the reaction vessel. In order to achieve uniform heating of the material on each tray, the oxygen-deficient gas so that the amount of gas per kilogram of dry biomass material processed on the tray is in the range of 1-24 kilograms (kg). To control the flow. The flow of oxygen-deficient gas through the tray may be continuous.

  An oxygen-deficient gas is a heat transfer medium that applies heat to and removes heat from the biomass material for drying and roasting. The gas flows through the biomass material and the tray.

  When the gas is at a higher temperature than the material, a continuous flow of oxygen-deficient gas through the material heats the biomass material. Also, when the material becomes hotter than the gas due to the exothermic roasting reaction, a constant flow of gas cools the material. When the material is overheated, the roasting reaction can react excessively. The continuous flow of gas causes the temperature of the biomass material in the reaction vessel to be in the same temperature range as the gas, or higher than the biomass material, for example, in the temperature range higher by 20-30 ° C. Control.

  The total retention period of the biomass material in the reaction vessel is 15 to 60 minutes. The holding period in the pressurized reaction vessel is selected according to the type of biomass material processed in the reaction vessel. For example, when wood is used as the biomass material, the total holding period in the reaction tank is 15 to 25 minutes.

  In order to achieve this retention period, the reaction vessel includes a stack of trays that contain biomass throughout. Biomass is dried in the upper tray and roasted in the lower tray and the lower chamber of the reaction vessel. The roasted biomass is cooled at the bottom of the reaction vessel or on a screw conveyor or other device downstream of the outlet to the reaction vessel.

  Stacked trays effectively form a series of moving beds for biomass in a compact vertical pressurized reactor. Each tray has a pie segment shaped opening through which the biomass material falls to the next lower height tray in the reaction vessel. After the biomass material moves around on the tray, it falls from the opening. The scraper may slide the material around the tray toward the opening. The rotation speed of the scraper is selected to provide the desired holding period on each tray. The holding period may be uniform for each tray in the reaction vessel. The holding period is realized by the selection of the number of trays for each of drying and optionally roasting and the time required to perform each of these processes. Because the cooling or roasting process may be performed on the biomass deposits in an open internal chamber of the reaction vessel, there is not necessarily a tray for these processes. Cooling may be performed after discharging the roasted biomass from the reaction vessel. Alternatively, the tray may be used for a roasting or cooling process in the reaction vessel.

  The roasting process mainly volatilizes the hemicellulose organic compound in the biomass material. These compounds are incorporated into the hot gas passing through the material and condense on the cold surface in the roasting reactor and in the conduit for the roasting gas, resulting in tar-like deposits. In order to reduce the deposition of these organic compounds, the surfaces of the roasting reactor and the gas exhaust conduit are minimized. Furthermore, the roasting gas is exhausted from the region of the reaction vessel having a high temperature in order to minimize the risk of organic compounds condensing on the surface of the exhaust conduit. In addition, the reaction vessel and the conduit may be insulated by, for example, a thermal barrier coating so that a high inner surface temperature can be maintained in the reaction vessel and the conduit. In addition, the inner surfaces of the outer walls and associated gas conduits in the trays and reaction vessels may be heated, for example with heat traced elements.

A pressurized reaction vessel configured to perform a roasting process on biomass was invented, the reaction vessel comprising:
A cylindrical reaction vessel wall extending substantially vertically;
A top plate that is insulated against the reactor wall and forms a pressure seal with the wall;
A rotatable shaft extending vertically downward from the top plate;
A plurality of scraper devices each attached to the shaft at a different height in the reaction vessel;
Multiple tray assemblies;
A reactor chamber below the tray assembly for conducting a roasting reaction on the biomass;
The bottom discharge port of the reactor where the roasted biomass is discharged;
Including
The reaction vessel wall may be insulated,
The shaft includes an insulated upper coupling configured to connect to a motor drive system;
Each of the tray assemblies cooperates with one of the scraper devices, and the scraper device is located immediately above the tray of the tray assembly,
The tray has a perforated, mesh or other configuration that allows gas flow to pass but not biomass, and each tray includes a discharge opening that transports the biomass from the tray to the tray of one lower tray assembly. It is a waste.

Alternatively, the reaction vessel may include a cooling zone at the bottom of the reaction vessel below the tray assembly and roasting chamber. The cooling zone is configured to hold and cool the roasted biomass before the biomass is discharged from the roasting reaction vessel. The lower zone of the reactor may function for passivation of the active sites in the biomass by injecting oxygen (0 ₂ ) generated by the atmosphere or nitrogen gas generator. The lower zone for passivation can be arranged below the cooling zone in the reaction vessel or at the position of the cooling zone.

A method for biomass roasting using a pressurized roasting reactor with stacked trays was invented, which method comprises:
Feeding biomass to the upper inlet of the reactor so that the biomass material is deposited on the upper tray of the vertical stack of trays in the reactor;
As the biomass moves over each of the stacked trays in the reactor, the biomass material is at least 3 bar gauge (eg, 3-20 bar gauge, or 3-15 bar gauge, or 3-5 bar gauge). Heat drying with oxygen-deficient gas injected into the reactor under pressure;
Dropping the biomass sequentially through the tray by passing the biomass through the opening of each tray and depositing the biomass on the lower tray, further depositing the biomass on the biomass deposits in the reaction vessel;
Roasting the biomass in the sediment;
Discharging the roasted biomass from the lower outlet of the roasting reactor;
Removing the volatile organic compounds by evacuating the gas from the tray stack;
This includes purifying the exhausted gas, removing the volatilized organic compound, and supplying the purified gas to the reaction vessel.

An oxygen-deficient gas is a superheated vapor, a gas that is substantially less oxygen (eg, less than 75%) than in the atmosphere, or a gas composed of about 2 percent (2%) or less oxygen and 98% or more other gases. It can be. Other gases may contain a substantial proportion of nitrogen and may include some of the reaction products from the roasting reaction vessel, such as carbon monoxide (CO), carbon dioxide ( CO ₂ ) and methane (CO ₄ ). Biomass may be pressurized before being supplied to the reaction vessel with a pressure transfer device. The tray can be a mesh, a screen, or have holes, and heating and drying the biomass involves passing gas through the biomass and the tray. The scraper device may be rotated to move the biomass material across the tray in an arched path. Alternatively, the scraper device and biomass may be rotated without rotating the inside of the reaction vessel. The opening in each tray may be a triangular section that extends from the shaft in the reaction vessel to the reaction vessel wall.

  The gas may be injected into the stack of trays at multiple heights, where the gas is hotter when injected at the lower height than the gas injected at the upper height. . The gas for drying the biomass may be injected at multiple heights in the reactor, but the gas for roasting is used for a single height of the stack of trays, e.g. for roasting. It is injected only in the uppermost tray. Biomass may continue to fall sequentially through the tray at a reactor height that is lower than the height at which the gas is extracted.

A method for the roasting of lignocellulosic biomass using a roasting reactor with stacked tray assemblies was invented, the method comprising:
Continuously supplying the biomass to the upper inlet to the roasting reactor so that the biomass material is deposited on the upper tray assembly of the plurality of tray assemblies stacked vertically in the reactor;
As the biomass travels through the reactor while being supported by the trays of each tray assembly, the biomass material is injected into the reactor with a gas that does not substantially oxidize the biomass and at least 200 bar gauge and at least 200 ° C. Heat drying at a temperature in the range of ˜400 ° C. (for example, 200 ° C. to 300 ° C. or 200 ° C. to 250 ° C. in the case of a dry gas and a baked gas higher than the dry gas by, for example, 5 ° C. to 100 ° C.) Sequentially dropping the biomass through the tray by passing the biomass through the opening of each tray and depositing the biomass on the tray of the next lower tray assembly;
It involves subjecting the biomass to a roasting reaction on the lower tray assembly and in the reactor chamber below the tray for drying, and discharging the roasted biomass from the lower exit of the roasting reactor.

  The tray of each tray assembly has a mesh, screen or holes, and heating and drying the biomass includes passing gas through the biomass and the tray. Each tray assembly may also include a scraper device above the tray and an extraction gas chamber below the tray. The scraper device or tray rotates to move the biomass across the upper surface of the tray.

  The gas injected for roasting is, for example, 5-100 ° C. higher than the gas injected into the upper tray assembly and used to dry the biomass. Further, a cooling zone for biomass may be below all tray assemblies, below the reaction vessel roasting chamber, eg, at the reactor discharge. The cooling gas injected into the cooling zone may be at a lower temperature than the gas injected into the cooling tray assembly, and the cooling zone is more than the temperature at which the roasted biomass is automatically burned when the biomass is exposed to the atmosphere. Cooling to a lower temperature, the cooling tray assembly cools the roasted biomass to stop or inhibit the roasting reaction.

  The gas extracted from the reaction vessel may be circulated to the reaction vessel by a blower or a compressor. The circulating gas may be passed through a cyclone, condenser or filter to separate particles and condensable byproducts such as organic compounds before flowing the gas through a compressor or blower. The gas circulated through the roasting tray assembly or roasting chamber may be heated before being injected into the reaction vessel. A portion of the gas extracted from the tray assembly may be directed to the combustor to generate thermal energy applied to the gas that is circulated through the roasting tray assembly. The extracted gas may also be used in other process steps associated with a roasting plant or roasting facility.

A pressurized reaction vessel was invented for performing a roasting process on biomass,
A cylindrical reaction vessel wall extending substantially vertically;
A top plate that is insulated against the reactor wall and forms a pressure seal with the wall;
Inlet nozzle for injecting oxygen-deficient gas into the reactor;
A rotatable shaft extending vertically downward from the top plate into the reaction vessel;
A stack of scrapers and trays extending from the top plate into the reactor;
A roasting chamber below the stack in the reaction vessel and receiving a biomass deposit discharged from the stack;
A roasting gas exhaust outlet at the height of the reactor below the stack and above the top surface of the biomass deposit;
Biomass outlet in the lower region of the reactor;
Including
The reaction vessel wall may be insulated,
The gas temperature of the oxygen-deficient gas injected from the nozzle at the upper height of the reaction tank is lower than the gas temperature of the oxygen-deficient gas injected from the inlet nozzle at the lower height,
The shaft includes an insulated upper coupling configured to connect to a motor drive system;
Each scraper is fixed to the shaft, rotates with the shaft, and is directly above the associated fixed tray, each tray being pierced to allow the passage of gas but block the passage of biomass, An opening through which the biomass passes and falls;
The stack includes a gas extraction chamber at a height below one of the trays and above one of the scrapers, the gas extraction chamber accepts gas passing through one of the trays, and the gas extraction chamber passes through the tray. Including a gas extraction port to exhaust gas,
The stack includes a plurality of lower scrapers and trays that are below the gas extraction chamber and do not have a gas extraction chamber between the lower scraper and the tray.
The roasting gas may be injected directly into the lower region of the reaction vessel, particularly into the biomass deposits in the reaction vessel. The roasting gas injected into these lower regions is, for example, 5 ° C. to 20 ° C. lower than the temperature in the reaction vessel at the lower part of the reaction vessel, that is, the portion where the gas is injected into the lower roasting section. Also good. The gas temperature of the inert gas injected from the nozzle at the lower height of the reaction tank is lower than the gas temperature of the inert gas injected from the inlet nozzle at the upper height. As an alternative in the reaction tank, the scraper device and biomass may rotate in the tray without rotating in the reaction tank.

A method for roasting biomass using a roasting reaction vessel with stacked trays was invented, which method comprises:
Feeding biomass to the upper inlet of the reactor so that the biomass material is deposited on the upper tray of the vertical stack of trays in the reactor;
Dropping the biomass sequentially through the tray by passing the biomass through each opening in the tray and depositing the biomass on the lower tray;
Heating and drying the biomass material with an oxygen-deficient gas as it moves through each of the trays on which the biomass is stacked;
Extracting the moisture-containing gas that has passed the biomass on the upper tray directly under each of the upper trays;
When the biomass is roasted in the lower tray of the stacked trays, holding the gas with the biomass until the biomass falls from the stacked trays into the biomass deposits in the reaction vessel;
Gas containing organic compounds volatilized by biomass roasting is extracted from the gas outlet of the reactor at a height between the stacked trays and biomass deposits, and the roasted biomass is extracted from the roasting reactor. It includes discharging from the lower outlet.

  The roasting and optional cooling of the biomass material may be performed on biomass deposits in the lower region of the reaction vessel. To facilitate roasting in the deposit, hot oxygen-deficient gas is injected into the reaction vessel at a predetermined height of the deposit so that the gas reacts through the deposit between the deposit and the stack of trays. You may make it raise to the area | region of a tank. An oxygen-deficient gas is injected into the deposit from a gas nozzle in the reactor wall to allow for roasting and optional cooling within the deposit of biomass in the reactor. The nozzle may be located on the central column in the reaction vessel or may extend through the reaction vessel sidewall. In order to provide cooling of the biomass material, a gas sufficiently below the roasting temperature, for example a gas of 200 ° C. or lower, is injected from a nozzle in the lowest region of the reaction vessel. This cooling gas flows in the direction of the biomass material and flows out from the bottom of the reaction vessel.

FIG. 1 is a side view of a pressurized roasting reaction tank.

FIG. 2 is a perspective view of the top and sides of the roasting reaction tank shown in FIG.

FIG. 3 is a cross-sectional side view of the roasting reaction tank shown in FIG.

FIG. 4 is a perspective view of the top and sides of the roasting reaction vessel shown in FIG. 1 and shows the internal components with a quarter of the reaction vessel removed for illustrative purposes.

FIG. 5 is a side view of the stack of tray assemblies, the top plate for the reaction vessel, and the motor and gear box assembly inserted into the upper opening of the reaction vessel shown in FIG.

6 is a view showing the top and sides of the stack of the tray assembly shown in FIG.

FIG. 7 is a perspective view of the spoke wheel scraper component of the tray assembly.

FIG. 8 is a perspective view of the top and sides of the tray plate component of the tray assembly.

FIG. 9 is a perspective view of the bottom and sides of the tray shown in FIG.

FIG. 10 is an isolation plate that is a component of the stack of tray assemblies, and for purposes of illustration, the plate segments are removed to show the isolation plate chute and support frame.

FIG. 11 is a side view of the isolation plate shown in FIG.

FIG. 12 is a view of the isolation plate shown in FIG. 10 as viewed from above.

13 is a perspective view showing the top and sides of the section of the support frame of the isolation plate shown in FIG.

FIG. 14 is a perspective view showing the bottom and sides of the top plate for the roasting reaction tank.

FIG. 15 is a cross-sectional view of the adiabatic coupling between the drive gearbox and the shaft for the stack of tray assemblies.

FIG. 16 is a cross-sectional view of the bottom end of the shaft in the stack of tray assemblies.

FIG. 17 is a cross-sectional view of a roasting reaction tank, and schematically shows gas flow into and out of the reaction tank.

FIG. 18 is a cross-sectional view of the upper portion of the roasting reaction tank, illustrating the drying of biomass in the reaction tank.

FIG. 19 is a top view of the mesh tray plate illustrated in FIG. 18 used for drying biomass.

FIG. 20 is a view of the isolation plate illustrated in FIG. 18 as viewed from above, and has an enlarged portion showing a seal between the reaction vessel and the isolation plate.

FIG. 21 is a cross-sectional view of the portion of the roasting reactor corresponding to the lower section of the stack of tray assemblies, illustrating the roasting process in the stack of tray assemblies.

FIG. 22 is a view of the mesh tray plate illustrated in FIG. 21 as viewed from above, and has an enlarged portion showing a seal between the tray plate and the reaction vessel.

FIG. 23 is a process flow chart illustrating the flow of biomass material and gas through the biomass roasting plant.

FIG. 24 is a process flowchart illustrating the roasting gas processing unit shown in FIG.

Detailed Description of the Invention

  1-4 illustrate an embodiment of a pressurized processing vessel 10 for receiving, drying, roasting, and cooling biomass material from a biomass source 12 via an upper inlet 14. . The biomass can be wood chips, wood pulp or other ground cellulosic materials. The biomass is dried, subjected to a roasting process and cooled to produce roasted biomass.

  The biomass may be completely or partially dried with an external dryer 15 before entering the reaction vessel. After passing through the upper inlet, the biomass enters the upper tray in the stack 16 of trays. The tray provides a moving bed cascade for drying and processing biomass. The upper tray is used to dry the biomass and the lower tray is used to subject the biomass to a roasting process. An insulating tray separates the drying trays from each other and the drying tray from the roasting tray.

  The upper inlet 14 to the pressurized reaction vessel is connected to a continuous supply and pressure isolation device, such as a conventional rotary valve or plug screw feeder, from a source of biomass at atmospheric pressure to pressurize the reaction vessel. Is supplied with biomass 12. The biomass source 12 provides lignocellulosic material that has been chipped or cut to have chip dimensions of 10-50 millimeters (mm) in length, 10-50 mm in width, and 5-20 mm in thickness. . The thickness of the chip may be other ranges, for example 20-30 mm, 15-25 mm or 3-10 mm. These chip dimensions are optimal for wood. Depending on the type of wood or non-wood material used in the biomass, other chip dimensions may be appropriate.

  Alternatively, the reaction vessel may be operated at or near internal pressure. Reaction vessels operating at or near internal pressure do not require the rotary valves or other types of airlocks required for pressurized reaction vessels.

  The biomass 12 is supplied to the inlet 14 to the reaction tank at a temperature of, for example, 80 ° C. to 120 ° C. or when the dryer 15 heats the biomass before entering the reaction tank. In the absence of a dryer, the biomass material may enter the reaction vessel at ambient temperature. Biomass is heated in the reaction vessel by pressurized hot oxygen-deficient gas. The gas entering the reactor is at a temperature in the range of 200 ° C. to 400 ° C. and is used to dry the biomass and promote the roasting reaction. In order to promote the roasting reaction, this gas is in particular one of the range of 250 ° C to 400 ° C, the range of 250 ° C to 300 ° C, and the range of 300 ° C to 380 ° C. The gas entering to dry the biomass may be cooler than the gas temperature that promotes roasting. The gas temperature for drying ranges from 200 ° C to 250 ° C. The volume of the oxygen-deficient gas supplied to the reaction tank is 1 to 8 kg, 1 to 12 kg, or 1 to 24 kg of gas with respect to 1 kilogram (kg) of dry biomass.

  Directly below the upper inlet 14 in the reaction vessel 10 may be a channel that accepts biomass from the inlet and directs the biomass to the upper tray 18. The biomass falls onto the upper tray and travels in a circular arc path across the tray until the biomass reaches the leading edge of the upper tray. Biomass falls through the opening to the next lower tray. The process of biomass moving over the surface of the tray, falling through the opening in the tray, and depositing on the next lower tray is repeated for each tray in the stack of tray assemblies.

  The biomass falls from the stack of tray assemblies and forms deposits in the chamber 20 of the pressurized reactor. While in the sediment, the biomass maintains an oxygen-deficient gas atmosphere and continues to convert to roasted biomass. Below the chamber 20, the reaction vessel converges in a convergence zone 22, facilitating the uniform flow of biomass through the chamber and the bottom of the reaction vessel to the bottom biomass outlet 24 of the reaction vessel. ing.

  A large access / observation port 26 in the reactor wall provides access to the biomass deposits in the chamber 20. Also, sensor ports, such as temperature and pressure probes, are placed at various heights and angular positions throughout the reaction vessel.

  Hot oxygen-deficient gas 28 is injected into the reaction vessel, for example, through top injection manifold 30 and through gas injection nozzles 32 located at various heights in stack 16 of the tray assembly. Gas passing through the biomass is discharged from the stack of trays and the reaction vessel by a gas extraction port 34 below the corresponding injection nozzle 32.

  In the embodiment shown in FIGS. 1-4, two gas inlets 30, 32 for oxygen-deficient gases are provided at the top of the reactor and corresponding to the tray assembly for biomass drying and the upper tray assembly for the roasting process. Present at height. Similarly, three gas extraction ports 34 are respectively below the corresponding gas inlets. Two of the gas extraction ports are adjacent to the tray assembly for drying. A third gas extraction port is in the upper region of the chamber 20. The number of gas outlets 34 is minimized to reduce the area of the metal surface that is exposed to the gas containing organic compounds from the biomass material.

  Oxygen-deficient gases flowing to multiple heights in the reactor will have different temperatures and compositions at different heights in the stack 16 and chamber 20 of the tray. For example, the highest height of the reaction vessel, for example, the hot oxygen-deficient gas introduced into the top inlet port 30, will be higher than the temperature of the biomass 12 entering the reaction vessel. The hot oxygen-deficient gas introduced through the nozzle 32 in the cylindrical wall of the reaction vessel will have different temperatures at different heights in the reaction vessel. The temperature of the gas gradually increases at a lower location in the stack of trays and becomes slightly higher than the temperature of the biomass as it descends through the stack. The biomass descends through the stack of tray assemblies and increases in temperature as it falls into the deposits in the chamber. At the lower height of the reaction vessel, the temperature of the gas introduced from the nozzle 32 is lower than the biomass at the corresponding height of the reaction vessel. The temperature of the gas injected at different heights is selected to form a temperature profile along the vertical direction of the biomass in the reactor. The gas is injected through the nozzle 32 so as to maintain a uniform temperature across the cross section of the reaction vessel at each height of the reaction vessel.

  By injecting an oxygen-deficient gas at a temperature slightly above the temperature of the biomass that is being heated by the gas, the efficiency of the heating is increased at a single temperature substantially higher than the biomass entering the reactor. Compared to when gas is injected at all heights.

  The roasting reaction can take place in the lower tray and chamber 20 of the stack of trays, and optionally only in chamber 20. The convergence zone 22 at the bottom of the reaction vessel is configured to promote a uniform downward flow of biomass material to the reaction vessel outlet 24. The lower chamber 20 is the hollow area of the pressure reactor below the tray stack. The lower chamber and the convergence zone extend to the lower half of the pressure reactor height or the lower two thirds. The convergence zone 22 is sold by Andritz Group and is described in US Pat. Nos. 5,500,083, 5,617,975 and 5,628,873. It can be a single converging section of “DIAMONDBACK®”. Alternatively, the convergence zone is a straight drop tube that includes multiple screw conveyors or moving grids at the bottom of the zone and at the exit of the reaction vessel. The convergence zone 22 is maintained at a temperature lower than the stack of tray assemblies used for roasting and is at a temperature lower than the temperature of the biomass material in the chamber 20.

  The pressure reactor 10 has dimensions, such as diameter and height, based on desired operating conditions, such as the composition of the biomass material and the volumetric flow rate of biomass into the reactor. Generally, on an industrial scale unit, the reactor has a height greater than 100 feet (30 meters) and a diameter greater than 9 feet (2.7 meters). The reaction vessel has a length to diameter ratio (L / D) in the range of 5/1 to 12/1, or in the range of 6/1 to 11/1, or in the range of 7/1 to 10/1.

  The volume of hot oxygen-deficient gas required in the reaction vessel is dramatically reduced in the pressurized reaction vessel 10 compared to a reaction vessel operating at atmospheric pressure. By pressurizing the treatment tank 10, the volume of the high-temperature gas required for heating the biomass can be reduced by 2 to 35 times compared to the reaction tank at atmospheric pressure. The reduction factor for the reaction vessel depends on the pressure in the reaction vessel.

  Since the volume of hot gas required in the pressurized reaction vessel is reduced, the volume, size and cost of the reaction vessel 10 are significantly reduced compared to a reaction vessel operating at atmospheric pressure. A pressurized reaction vessel into which hot gas is injected provides efficient and economical heat transfer from the gas to the biomass in the reaction vessel.

  The oxygen-deficient gas 28 injected into the reaction vessel 10 is a high temperature, clean gas (compared to the gas extracted from the roasting reaction in the reaction vessel), and an organic compound that can be deposited on the surface of the reaction vessel. And other chemical substances are substantially free. As the gas passes through the biomass, organic compounds can be incorporated into the gas and condense on the relatively cool surface of the reaction vessel. Considering the possibility of condensation, the gas passages downstream of the biomass are made large and are substantially free of small passage nozzles and other surfaces that can become clogged when organic compounds condense on the surface.

  In the embodiment shown in FIGS. 1-4, the top gas inlet 30 is a single inlet for dry gas. The nozzles 32 on the side walls of the reaction vessel are limited to a small number, for example 2 to 4 nozzles, that inject hot gas directly through the reaction vessel walls.

  The inflow of heated gas into the pressure reactor, the flow through the pressure reactor, and the outflow from the pressure reactor will facilitate the flow of hot pressurized gas through the tray assembly at the top of the reactor. In this reactor, the biomass continues to be heated to the desired temperature for roasting and then cooled. As shown in FIG. 1, hot oxygen-deficient gas is reacted from top injection manifold 86 and gas injection nozzles 34 located at various heights in tray assemblies 16, 18 and 20 in the upper portion of the reaction vessel. It may be injected into the upper section of the tank 10.

  The gas flowing to multiple heights in the reactor is at different temperatures and compositions in each of the tray assemblies. For example, the hot oxygen-deficient gas 28 introduced at the highest height of the reaction vessel is slightly higher than the temperature of the dried biomass 12 that continues to be supplied to the reaction vessel, for example, 5 ° C to 100 ° C. is there. The hot inert gas introduced into each of the lower plurality of subsequent heights in the reactor is gradually heated to a temperature slightly higher than the temperature of the biomass in the reactor that approximates the injected hot gas. It becomes. By injecting the oxygen-deficient gas at a temperature slightly above the temperature of the biomass that is being heated by the gas, the efficiency of the heating is injected at a single temperature that is substantially higher than the biomass entering the reactor. It increases compared with the case of doing. Alternatively, the gas injected for drying and roasting can have a substantially similar temperature and composition, and the gas for cooling the biomass can be extracted from other cooler heights in the reactor. Can be recirculated gas. For example, the exhaust gas from the drying tray is lower than that from the roasting height and lower than the temperature required for roasting.

  Before the roasting reaction takes place in the reaction vessel, the biomass may be dried and heated to a temperature of 200 ° C. or a range of 180 ° C. to 250 ° C. or 200 ° C. to 300 ° C. in an oxygen-deficient environment. Drying may occur partially or completely in the dryer 15 upstream of the reaction vessel 10 or in the drying tray assembly in the upper portion of the stack 16. The biomass is heated directly using an oxygen-deficient gas, such as superheated steam, nitrogen or mixtures thereof, injected into the top of the reaction vessel or a dryer. The drying process is performed at a temperature lower than that used to cause biomass roasting and at a temperature at which the biomass does not release large amounts of organic compounds.

  The compounds released in the drying tray assembly are mainly water and highly volatile (relatively light) organic compounds, and the condensation of water does not cause fouling. Similarly, light organic compounds tend not to leave tar-like deposits in the reactor and the conduit for the extracted roasting gas. Exhaust gas from the drying tray assembly is removed from the reaction vessel without creating large deposits on the surface of the reaction vessel. Water and light organic compounds are separated from the gas after the gas is extracted from the reaction vessel or circulated as excess gas in the roasting section of the reaction vessel.

  The gas exhausted from the roasting process can condense on the surface or material of the reaction vessel when the surface of the reaction vessel or the biomass material cools to a roasting temperature, e.g., below 250 ° C to 200 ° C or 160 ° C. Rich in organic compounds. These condensed compounds accumulate in the form of tar-like material on the surface of equipment and conduits, causing reactor blockage and improper operation.

  Insulate and heat traced reaction vessels, pipes, tanks and other equipment with surfaces in contact with organic-rich gases to prevent or minimize condensation to cooler surfaces Try to minimize. Another technique for minimizing condensation on the surface is to minimize the surface exposed to organic rich gases. By using the open chamber 20 for part or all of the roasting process, surfaces exposed to gases rich in organic compounds, especially surfaces of small passages, are minimized. Eliminating some or all exhaust chambers between trays for roasting also minimizes the surfaces that receive tar deposits of organic compounds.

  Gases containing heavier organic compounds from the roasting of biomass are extracted from the reaction vessel via one or more lower gas extraction ports 34. After being removed from the reaction vessel, the gas from roasting is cooled and cooled to condense a portion of the organic compound, but at a temperature higher than the dew point of water or a lighter organic compound. It is maintained at a temperature higher than the condensation temperature. As organic compounds condense, they form aerosols, mists or droplets in the gas stream. A cyclone, drop out tank or other separator device separates the condensed organic compound from the gas stream. Once separated from the organic compounds, these gases pass through a blower or other pressure increase device and are heated to a temperature above the roasting temperature and re-injected into the reaction vessel, for example at the tray assembly.

  The condensed liquid organic matter circulating flow is circulated and sprayed in the aerosol-containing gas discharged from the condenser prior to the cyclone separator. This provides a stream of large droplets of liquid organic matter that collects a portion of the aerosol and improves the removal of organic matter from the gas stream. The condenser may be used to cool the roasted gas from the reaction vessel. The condenser is cooled using a suitable heat exchange fluid. The energy obtained by the heat exchange fluid may be used to reheat the circulating gas after the heavier organic components have been removed.

  When cooling gas is injected into the convergence zone 22 in the lower region of the reaction vessel, the cooling gas is cooler than the gas 28 injected for drying and roasting. The cooling gas may lower the temperature of the biomass to be lower than the temperature that causes roasting. The cooling gas may be a circulating gas extracted from the upper height in the reaction vessel, such as the exhaust gas from the tray stack 16 or chamber 20.

  The temperature in the convergence zone 22 may be lower than the temperature required for roasting, for example less than 265 ° C, less than 240 ° C or less than 200 ° C. The roasting temperature depends on the pressure in the reaction vessel 10 and the composition of the biomass material. The temperature in the convergence zone 22 is at least 15 ° C. to 40 ° C. lower than the temperature of the chamber 20. In order to control and maintain the temperature in the convergence zone, gas is injected into the chamber 20 via the injection nozzle 21 (FIGS. 1-4) to cool or heat the biomass. Cooling or heating gas is injected into the convergence zone via the nozzle 23. Cooling gas injection and extraction can occur at various heights in the convergence zone 22. The temperature of the cooling gas is controlled to be lower than the temperature at which the biomass material automatically burns.

  FIG. 5 is a side view of a stack 16 of trays having cover plates 36 and sleeves 38. FIG. 6 is a perspective view of the top and sides of the stack 16 of trays. The stack of trays is vertically oriented and coaxial with the shaft 38 and the circular top plate 36.

  The tray stack 16 is supported in the reaction vessel 10 by a central vertical shaft 42 that is rotatably attached to a cover plate 36 at the top of the reaction vessel. The cover plate 16 can be a flat plate, a hemispherical plate, an elliptical plate, or other plate that provides a sealable cover at the top of the reaction vessel. The cover plate may have a wide annular flange that is bolted to, welded to, or otherwise secured to the mating flange of the vertical cylindrical wall to the reaction vessel. The wide flange facilitates removal and replacement of the cover plate when the tray stack 16 is repaired or replaced.

  Directly above the cover plate is a gearbox and electric motor assembly 40 that drives the shaft 42 to rotate the tray stack scraper or tray. The vertical sleeve 38 provides a cylindrical housing for the upper end of the shaft and at least the lower portion of the gearbox and motor assembly.

  The tray stack with the shaft can be removed as a unit stacked from the reaction vessel by removing the top cover plate. A crane is used to pull the stack of trays out of the reaction vessel. The stack of trays can be cleaned, replaced or otherwise serviced outside the reaction vessel. Removing the stack of trays facilitates access to the interior of the reaction vessel for service and cleaning. The crane is used to insert the stack of trays back into the reactor, attach the cover plate to the top of the tray, and attach the motor and gearbox to the top of the shaft.

  The shaft 42 extends downward through the stack of trays and is supported by a bottom bracket 44. The bottom bracket includes a lower bearing that receives the lower end of the shaft 42. The bottom bracket includes a cylindrical bottom plate 46 that provides bottom support to the stack and shaft of the tray. A metal strap or bar 47 extends vertically between the bottom plate and the cover plate 36. These straps or bars form the outer cage for the tray and help maintain the orientation of the tray within the stack. A strap or bar may be connected to the outer periphery of each non-rotating tray assembly and separator plate in the stack. These connections help to maintain the horizontal orientation of the tray assembly and the separator plate.

  The tray stack 16 includes a tray assembly, each tray assembly including an annular scraper 48 and a circular tray plate 50. The scraper is coaxial with the shaft 42 and is fixed to the shaft 42. The scraper rotates together with the shaft to move the biomass so as to draw an arc-shaped path on a plate immediately below the scraper. The tray plate 50 is coaxial with the shaft and is fixed. Each tray plate 50 has an opening through which biomass falls from that plate to the next tray plate.

  The isolation plate 52 separates the upper exhaust gas chamber 54 from the lower inflow gas chamber 56. The isolation plate isolates adjacent tray assemblies, and in particular isolates the gas flow in the adjacent tray assembly. The gas chamber, in particular the lower chamber, is substantially open and has no structural surface. A chute 58 provides a vertical passage for biomass that flows from the upper tray assembly through the isolation plate to the lower tray assembly. The chute has side walls that separate the biomass falling through the chute from the gas in the gas chambers 54,56. A gas extraction port 34 (FIGS. 1 to 4) is disposed with the exhaust chamber 54, and similarly, the gas injection nozzle 32 is disposed with the lower inflow gas chamber 56.

  The upper tray assembly 60 is used to dry the biomass material. Two of these drying assemblies 60 are shown in FIGS. 5 and 6, but are separated by gas chambers 54 and 56, respectively. By drying, moisture is released from the biomass and taken up into the gas. By allowing the gas with moisture to flow into the gas exhaust chamber 54 below each drying tray plate, these gases can be exhausted through the gas extraction port below each drying tray plate, The drying process is improved. Furthermore, biomass tends to not release significant amounts of organic compounds during the drying process if the biomass does not reach the roasting temperature. Due to the limited amount of organic compounds, the exhaust gas from the drying tray assembly 60 tends not to coat the chamber 54 and the exhaust port 34 with tar-like organic deposits.

  The lower tray assembly 62 is used for roasting by operating at a higher temperature than the drying tray assembly 60. Through the roasting process, organic compounds are released by the biomass and taken up into the gas that passes through the biomass. Organic compounds condense on relatively cool surfaces and block narrow passages and moving parts. Further, in the lower tray assembly, a relatively small amount of moisture is released into the gas by the biomass, and only a small amount of moisture remains in the biomass after the drying tray assembly 60. In order to avoid condensation of organic compounds on the surface, and in view of the small amount of moisture released, gas is not extracted directly under each tray assembly, but in two of the lower tray assemblies 62. Pass through the above. In the example shown in FIGS. 5 and 6, the gas flows downward through the three tray assemblies 62 and is exhausted into the chamber 20 through the bottom plate 46. By eliminating the gas chamber between the lower tray assemblies 62, the tar coated surface is reduced.

  Present on the tray assembly, especially on the lower tray assembly 62 where there is a large temperature change between the biomass and the surface of the tray or other surface of the reaction vessel, directly above the surface of the tray or near the entrance of the biomass to the tray Biomass is relatively cold. In order to avoid condensation of organic compounds in the biomass at the tray inlet, the tray inlet can be additionally heated to avoid condensation. This additional heating can be achieved by a baffle because the baffle plate can remove some of the hot incoming gas from the inlet section of the tray, which can condense at lower temperatures, or other trays. This is because it is directed directly to the section or reaction vessel surface.

  The net flow of gas flowing down through the stack 16 goes down and toward the chamber 20. In order to prevent condensation in the reaction vessel, aerosol formation, and surface contamination, the gas from roasting is extracted at a height in the reaction vessel corresponding to the peak gas temperature in the reaction vessel. This height is in the chamber 20. A lower gas outlet 34 is in the upper region of the chamber 20 and corresponds to the hottest region in the reaction vessel. By extracting the gas from the roasting process only while the biomass is hottest in the reactor and higher than a threshold temperature, e.g. 280 ° C., when the gas is exhausted from the reactor, The risk of excessive tar accumulation is reduced. Similarly, by reducing or eliminating gas chambers between the lower tray assemblies, the tray assembly and reaction vessel surfaces exposed to gases containing organic compounds can be minimized.

  The roasted biomass material is discharged from the reaction vessel 10 under pressure. The biomass material is discharged to a pressure transfer device that reduces the pressure of the material to atmospheric pressure. From the pressure conveyor, the roasted biomass is moved to another process using a screw conveyor as shown in FIG.

  The number of tray assemblies in the stack 16 depends on the design requirements of the reactor, particularly the desired holding time for drying and roasting. For example, the total number of tray assemblies in the reaction vessel 10 can be either in the range of 3-10 and in the range of 4-6. The percentage of the drying tray assembly can be 20-100%, or 20-50% or 40%, and the remaining tray assembly can be used for roasting. However, these ranges are exemplary and do not define a limit on the number of tray assemblies.

  FIG. 7 is a perspective view of the scraper 48 in each of the tray assemblies 60 and 62. As shown in the present embodiment, the scraper 48 has a central shaft collar 64 and has a shape similar to a wheel of a carriage, and the collar 64 slides on the shaft and is locked to the shaft. An annular ring 66 is on the outer periphery of the scraper and vertical vanes 68 extend generally radially from the collar to the ring. The vanes may be offset from the radial line by an angle, for example 5-15 degrees, if it is desired to facilitate the movement of the biomass material filling the pie-shaped chamber 72 between the vanes. Ribs 70 are used to align the tray assembly within the stack or to align the stack when inserted downward into the reaction vessel. Further, the ribs 70 may remove deposits on the straps or bars 47 and other surfaces as the scraper rotates. The height (h) of the scraper is sufficient to ensure that the biomass moves across the tray and extends substantially throughout the gap between the plates, especially in the lower tray assembly 62. It is done.

  8 and 9 are perspective views of an exemplary tray plate 50. FIG. The tray plate includes a substantially circular screen plate 82, which is a perforated, mesh or other form that allows gas flow to pass but not biomass material. The plate may be supported by ribs 84 and an outer ring 88 that extend radially from the collar 86. Arranging the ribs, collars and rings provides structural support for the tray plate and minimizes the surface area of the plate, especially the tray plate used for roasting. The outer ring 88 includes an arcuate portion 90 that is inclined radially inwardly downward. The arc portion 90 is disposed with the pie-shaped opening 92 and deflects the biomass inwardly away from the reaction vessel wall. The collar 86 is coaxial with the vertical shaft of the reaction vessel that rotates inside the collar. Alternatively, the collar may be fixed to the shaft such that the tray plate 50 rotates with the scraper fixed.

  Pie-shaped openings 92 in the tray plate 50 allow biomass material on the circular screen plate 82 to fall to the next tray assembly. The screen plate 50 may have a solid pie-shaped plate 94, which is the pie-shaped opening of the tray assembly directly above the solid plate 94 or the tray. Is aligned with the biomass inlet chute at the top of the reactor. The solid plate 94 may have an area larger than the area of the opening 92. The solid plate provides a solid pad that receives the falling biomass material. As biomass material flows from one plate to the other plate below it, the biomass material lands on the lower plate at a temperature slightly below the temperature of the biomass that is already moving on the lower tray. The solid plate may include an electrical heating element that facilitates heating of the biomass. Furthermore, the solid plate prevents roasting gas rich in organic matter falling with biomass from passing straight through the screen plate and condensing on the tray support structure for the tray.

  The opening 92 in each tray plate is in the farthest region of the plate with respect to the biomass path on the plate. The solid plate 94 is at the origin of the biomass passage on the plate and is aligned with the rear end (in the direction of biomass movement) of the opening 92. This alignment of the solid plate and the opening ensures that the biomass entering each tray assembly is retained on the tray plate for almost the entire rotation time of the scraper or tray plate.

  The openings 92 are arranged vertically in a staggered manner so that the openings are located on the solid plate of the tray plate immediately below the openings. By aligning the opening 92 onto the solid plate, the biomass falls through the opening onto the solid plate. As the plate or tray rotates, the biomass slides from the solid plate around the entire upper surface of the tray plate in a circular path to the plate opening. By maintaining the biomass on the upper surface of each tray, the biomass retention period on the tray plate is maximized, thereby heating and drying the biomass and promoting roasting.

  10-13 illustrate an isolation plate 52 for a stack of tray assemblies. The isolation plate forms a solid, heat-insulating, and substantially non-transparent horizontal wall inside the reaction vessel. The isolation plate 52 is used to separate the gas chambers 54, 56 within the stack 16 of the tray assembly. Isolation plate 52 is used to define the bottom wall of exhaust gas chamber 54 and the top wall of inflow gas chamber 56.

  Chute 58 extends through isolation plate 52 to provide a passage. The chute is oriented substantially vertically and has a cross-sectional shape that matches the shape of the pie-shaped opening 92 of the tray assembly directly above and below the isolation plate 52. The chute may have a vertical wall that extends across the entire circumference of the chute and has a cross-sectional shape that matches the opening 92 of the plate tray. The chute walls confine the biomass in the chute region and prevent the biomass from entering the gas chambers 54,56. This wall consists of a solid or mesh that can entrap the biomass material. In addition, the wall is bracketed with vertical ribs, for example, to provide structural support for the wall.

  The isolation plate 52 is formed as an assembly of pie-shaped sections 98, each pie-shaped section 98 having a horizontal plate, support ribs and an arcuate inner support and an arcuate outer support. The isolation plate may be solid, for example formed of steel or other metallic material. The heat insulating layer is attached to the lower surface or the upper surface of the metal plate in the isolation plate. Alternatively, the heat insulating layer may be sandwiched between an upper metal sheet and a lower metal sheet to form an isolation plate. The pie-shaped section 98 of the isolation plate can be joined by a bracket I beam strip 100.

  Isolation plate 52 is secured for a chute provided on the plate that allows biomass to flow down through the plate. The isolation plate is supported by vertical strips 47 (FIGS. 5 and 6) on the outer periphery of the stack 16 of the tray assembly. The isolation plate is secured to remain angularly aligned with the tray to ensure that biomass material falls from the upper plate to the lower plate through the opening in the isolation plate. The isolation plate has a collar 102 formed by a chute and pie-shaped section 98 assembly. The collar is coaxial with the shaft and surrounds the shaft. Because the isolation plate is fixed, the collar remains fixed as the shaft rotates.

  FIG. 14 is a perspective view showing the bottom and sides of the cover plate 36. The cover plate is formed of a metal plate having an optional heat insulating layer. The heat insulating layer may be sandwiched between metal sheets forming the plate, or may be attached to the outer surface and the inner surface of the metal plate. An upper inlet 14 for biomass extends through the cover plate 36, opens into the interior of the reaction vessel, and is aligned with the solid plate 94 of the top tray assembly. The gas inlet 30 in the cover plate is relatively small compared to the inlet 14 for biomass material.

  A channel 104 is disposed with the inlet 14 and extends downward from the cover plate. This channel directs the biomass material to the uppermost tray assembly and helps distribute the biomass within the scraper chamber in the uppermost tray assembly. The channel is a pair of L-shaped walls on either side of the inlet 14. A bearing 106 in the central opening of the cover plate receives a shaft for the stack of tray assemblies. A cylindrical sleeve 38 for the gearbox is coaxial with the central opening with the bearing 106. The sleeve has a large open area to allow access to the gearbox for service.

  FIG. 15 is an enlarged cross-sectional view of the coupling 108 between the shaft 42 for the stack of tray assemblies and the drive shaft 110 of the gearbox assembly in a cylindrical sleeve 38 at the top of the cover plate. The coupling 108 is insulated to avoid loss of excess heat from the inside of the reaction vessel via the shaft 42 to the outside of the reaction vessel. The coupling includes an insulating disk 112 between the end of the shaft 42 for the stack 16 and the end of the drive shaft 110. The heat insulating disk 112 is sandwiched between the shafts. The thermal insulation disk 112 may be a laminate of outer steel disks and a thermal insulation layer between the disks.

  The shafts 42, 112 are connected by a pair of annular collars 116 and the annular flanges 114 on each collar are bolted together to ensure that the shaft 42 of the stack rotates due to the twisting of the drive shaft 110. . A ring 118 between the collars 116 maintains the proper spacing between the shafts so that the insulating disk 112 is not destroyed.

  FIG. 16 is an enlarged cross-sectional view of the lower end of shaft 42 for stacking tray assemblies. A bottom plate 46 supports the stack 16 and provides structural support for the spindle bearing 120 shown in FIG. A vertical bracket 121 provides structural rigidity to the bottom plate and supports the shaft 42.

  The collar 64 of each scraper 48 is fixed, for example, locked to the shaft 48 so that the scraper rotates with the shaft. A slip ring 122 maintains the arrangement between the lowermost scraper 48 and the shaft 48. Between each of the scrapers, the shaft has a bushing 124 adjacent to the collar 86 of each tray plate 46. The collar forms a bushing that allows its corresponding tray plate to remain fixed.

  FIG. 17 is a schematic view of the pressurized reaction vessel 10 showing the flow of biomass material, for example, wood chips, shown in a dot pattern in the reaction vessel. The shaft for the stack of tray assemblies is supported by a spindle bearing 120 secured to the bottom plate 46 by brackets 121. The scraper is not shown in FIG.

  Two upper tray assemblies 60 are configured to dry the biomass material. These upper tray assemblies have an upper oxygen-depleted gas chamber 56 directly above the scraper for each tray assembly. The oxygen-deficient dry gas 126 for drying flows in through the gas nozzle 32, which is arranged to distribute the gas uniformly on the scraper and on the biomass that is moved by the scraper. The dry gas 126 may be supplied from the same gas source that provides the oxygen-deficient gas 128 for roasting, as exemplified by the gas source 28 in FIG. Alternatively, the source of drying gas 126 may be different from the source of roasting gas 128. The temperature of the oxygen deficient dry gas 126 for drying may be increased due to the dry gas injected at the lower height of the upper tray assembly.

  As biomass travels over the trays, the oxygen-deficient gas flows down through the trays of the biomass and tray assembly and enters the exhaust chamber 54 under each tray. An isolation plate 52 separates the upper tray assembly from the lower tray assembly 62 that separates each other and promotes roasting.

  The lower tray assembly 62 is configured for roasting. These tray assemblies do not have an exhaust gas chamber below each assembly. There may be a single incoming gas assembly above the top tray assembly 62. Hot roasted oxygen-deficient gas 128 for roasting flows through nozzle 32 above the scraper for the top assembly of lower tray assembly 62. The high-temperature roasted oxygen-deficient gas 128 is set to a temperature that promotes roasting, for example, a temperature that is 10 to 30 ° C. higher than the maximum temperature of the dry gas 126. Hot roasted oxygen-deficient gas 128 enters the reactor and flows down through all of the lower tray assembly 62 and the bottom plate 42 of the stack of tray assemblies. Hot roasted oxygen-deficient gas 130 is exhausted through an outlet 34 below the stack and above the biomass 132 deposit in the chamber 20 of the reactor 10. The hot roasted oxygen-deficient gas 130 is exhausted from the hottest region of the reaction vessel. The exhausted roasted oxygen-deficient gas may be purified and heated and used as the oxygen-deficient dry gas 126 and the high-temperature roasted oxygen-deficient gas 128.

  Additional hot roasted oxygen-deficient gas 128 may be injected directly into chamber 20 and biomass deposits. Additional hot roasting gas can be injected from the convergence zone of the reaction vessel, for example from a nozzle in the middle of convergence. The additional hot roasted oxygen-deficient gas may cause the biomass to flow upward so that it is countercurrent to the downward movement of the biomass. This countercurrent flow may be exhausted from the gas outlet 34 while exhausting the roasting gas from the stack of tray assemblies. Other roasting gases may be exhausted from the reaction vessel or injected into the reaction vessel via a discharge port 132 at the bottom of the reaction vessel.

  FIG. 18 is a schematic view of the upper portion of the pressurized reaction vessel 10, particularly the upper tray assembly 60. The oxygen-deficient gas enters the upper inlet 30 through the cover plate at a relatively lower temperature than the oxygen-deficient gas injected at the lower height of the reaction vessel. The oxygen-deficient gas may be distributed by a rectifying plate 136 that uniformly disperses the gas over the biomass. The gap (G) above the biomass material provides sufficient volume to evenly distribute the gas. The gap (G) is several inches, for example 5-8 inches, ie 150 mm to 200 mm. The hot oxygen-deficient gas flows down through the biomass material (shown in the pattern of dots in the figure), flows through the mesh or screen tray plate 82 and into the exhaust chamber 54, where a single exhaust outlet 34. Spill from. The exhaust outlet 34 is located adjacent to the chute for the isolation tray 52 immediately below the outlet 34. A gas inlet 32 for the next lower tray assembly is also located adjacent to the chute.

  The isolation tray 52 is shown in FIG. 18 as a laminate of a metal layer and a thermal insulation layer. The tray includes an upper layer and a lower layer of steel and an intermediate layer of a non-metallic thermal insulation layer. By insulating the isolation tray, the thermal efficiency in the reaction vessel is improved, and a substantially large effect is obtained between adjacent tray assemblies used for drying, for example, an effect of more than 10 ° C.

  FIG. 19 shows a tray plate 82 for the upper tray assembly used to dry the biomass material. This tray plate is formed as a mesh. Immediately below the plate 82 is a heating element 138 illustrated by a radial dotted line. The heating element can be an electrical resistance element, a conduit containing steam or other hot oxygen-deficient gas, or other device, such as a tray plate, especially when cold and wet biomass is deposited on the plate. Heat energy is applied to the solid plate 94 that receives the heat. The heating element is to apply heat to the tray plate to avoid organic compounds and other materials from depositing on the colder portions of the screen plate. Alternatively, high temperature gas may be blown to the lower side of the tray structure. The direction of rotation of the scraper is shown as a clockwise direction.

  FIG. 20 is a view of the isolation tray plate 52 as viewed from above. An annular brass or flexible glass fiber ring 140 forms a seal between the periphery of the tray plate 52 and the reaction vessel wall. The tray plate 52 may have heating elements that prevent cooling of the plate, thereby preventing condensation of organics and other compounds on the metal surface.

  The outer wall of the reaction vessel may be insulated by applying a thermal barrier coating to the outer surface of the metal wall 142, for example. Wall insulation may be provided over the entire outer surface of the reaction vessel. The thermal efficiency of the reaction tank is improved by the heat insulation of the outer wall of the reaction tank, and the uniform temperature level of the entire height of the reaction tank can be further maintained.

  The enlarged portion shown in FIG. 20 illustrates a brass or glass fiber seal 140 between the periphery of the isolation tray plate 52 and the inner surface of the cylindrical metal wall 142 of the roasting reactor. The wall 142 may be coated with a thermal insulation material 144, such as a ceramic coating, a glass fiber coating, or a high temperature polymer coating.

  FIG. 21 is a schematic view of the upper portion of the pressurized reaction vessel 10, particularly the lower tray assembly 62. In order to better illustrate the flow of gas (see arrows) and the movement of biomass material (see dotted pattern), the scraper is not shown. The oxygen-deficient gas enters the uppermost tray assembly 62 from, for example, two nozzles 32 that are arranged, for example, 180 degrees apart on both sides of the reaction vessel. The gas entering the top tray assembly 62 is at a high temperature, for example, higher than a temperature in the range of 240 ° C. to 300 ° C. to facilitate roasting of the biomass in the tray assembly 62 and the chamber 20. The temperature required to promote roasting depends on the biomass material and the pressure in the reaction vessel. The oxygen-deficient gas injected into the uppermost tray assembly 62 is higher than the oxygen-deficient gas added to the upper tray assembly 60 used to dry the biomass, for example, at a temperature 5 ° C to 100 ° C higher.

  The gap above the biomass material and scraper on the top tray assembly 62 provides sufficient volume to distribute gas evenly. Although similar to this gap, a similar gap exists between the lower surface of the tray plate 82 and the top of the scraper / biomass level in each of the lower tray assemblies 82. The initial gap above the top tray assembly 62 may be several inches, such as 5-8 inches, or 125 mm to 200 mm, and the lower gap may be 3-5 inches. The hot oxygen-deficient gas flows down through the biomass material (shown in a dot pattern) and through the mesh or screen tray plate 82 to the gap above the biomass and scraper on the next lower tray assembly 62. Flows directly into.

  The hot gas passes down each of the lower tray assemblies 62 and exits an outlet 34, for example, a single outlet below the stack of tray assemblies and above the biomass deposits in the reactor chamber 20. . The single outlet 34 is arranged according to the height of the reaction vessel where the hottest gas or a gas having a temperature substantially higher than the condensation temperature of the organic compound in the gas is present. By extracting the gas from the outlet 34 while it is very hot, the risk of organic compounds depositing on the reaction vessel and outlet surfaces is reduced.

  There may be a single outlet 34 for the gas passing through the biomass material undergoing the roasting process. By having a single outlet, the outlet surface exposed to exhaust gases containing organic compounds that volatilize during roasting is minimized. By minimizing the surface of the outlet and the associated outlet conduit, the surface area that can be plugged with deposits from the exhaust gas, such as tar-like organic material, can be reduced.

  FIG. 22 is a top view of the tray plate 82 of the lower tray assembly used for biomass roasting. The tray plate may be a metal mesh having mesh openings that are substantially the same size as the tray plate of the upper tray assembly. Alternatively, the plate mesh opening may be smaller than the plate mesh opening in the upper tray assembly. The tray plate 82 of the lower tray assembly has a pie-shaped opening 92 and a solid pie-shaped plate 94 below the chute or opening 92 of the next higher isolation plate or tray assembly. The plate 94 is adjacent to the opening 92 so that after biomass has fallen onto the plate 94, it travels around the entire plate 82 before dropping through the opening 92.

  A fixed seal 144, such as an L-shaped vertical wall, is disposed vertically with the tip of the pie-shaped plate 94 and includes a flange attached to the inner wall of the reaction vessel. The fixed seal is between the top edge of the scraper and the bottom of the tray plate located at the next height. The seal 144 directs the flowing gas from the tray plate opening into the biomass while the biomass is falling from the upper tray assembly.

  FIG. 23 is a flow diagram of a plant, for example a factory, for producing roasted biomass material 151 from biomass material 150. Bucket elevator 152 and drag conveyor 154 convey biomass material 150 to supply bin 156, which provides a continuous supply of biomass material at a flow rate determined by a meter screw at the bottom of the supply bin. Then, the second bucket elevator 158 conveys the biomass moving at a uniform flow rate to the inlet rotary valve 160 at the top inlet of the roasting reaction tank 162. The rotary valve may be a high-pressure conveying device that conveys unpressurized biomass material to the pressurized roasting reaction tank 162 without pressure loss from the reaction tank. The roasting reaction tank is a cylindrical pressurized reaction tank having a height of 30 to 50 meters and a diameter of 3 to 10 meters. These dimensions are exemplary, and the actual dimensions of the roasting reactor will depend on various factors including the type of biomass material, the desired flow rate of the material, and the pressure in the reactor.

  A discharge transfer screw 164 removes the roasted biomass material from the bottom of the roasting reactor at a metered flow rate. The cooling screw 166 removes thermal energy from the material while carrying the roasted biomass material, for example, by cooling vanes on the outer surface of the screw 166 or by cooling water flowing over the outer surface of the screw. Other cooling devices may be used in addition to or instead of the cooling screw. These other cooling devices may include fluidized bed coolers.

  The cooled roasted biomass material passes through the discharge rotation valve 168, which reduces the pressure of the material to atmospheric pressure and exposes the material to the atmosphere. The roasted biomass material is cooled prior to exposure to air, minimizing the risk of spontaneous combustion of the material.

  Third bucket elevator 170 and second drag conveyor 172 carry the cooled, roasted biomass material to storage bins 174. A metering screw discharges the biomass material 151 from the storage bin for further processing or use as combustion fuel.

  The heating or thermal energy 176 for the dry gas processing unit 178 and the roasted gas processing unit 180 is provided by steam, combustion or other energy sources. Thermal energy 176 provides a means to increase the temperature of the gas injected into the roasting reaction vessel 162. A gas processing unit for dry gas 178 removes dust and other particles from the circulating dry gas and reheats the gas to the temperature required for drying. The roasted gas processing unit 180 removes dust and other particles from the circulating roasting gas, removes heavier organic compounds, enables heat recovery, and reuses as roasting gas Reheat the gas to the temperature required to do so.

  The gas circulating through the gas processing units 178 and 180 is at substantially the same pressure as the pressure in the roasting reaction vessel. The pressurization of the gas can be realized by adding an oxygen-deficient gas to the reaction vessel or the gas processing unit or removing the oxygen-deficient gas from the reaction vessel or the gas processing unit.

  Oxygen-deficient gas is circulated through the roasting reactor in a substantially closed gas loop system. The gas is used to dry the biomass, apply heat to maintain roasting, or cool the roasted biomass. The temperature of the oxygen-deficient gas flowing into the tray is set to achieve the desired function of the tray. For example, the gas flowing to the top inlet is cooler than the oxygen-deficient gas flowing to the roasting tray assembly.

  The dry gas processing unit 178 provides a heated oxygen-depleted gas for the drying process that occurs in the roasting reaction vessel to dry the biomass material. The dry gas may provide an oxygen-deficient gas source such as nitrogen or dry steam. Dry gas from the dry gas processing unit flows to a gas nozzle 32 disposed with the upper tray assembly in the roasting reaction vessel. After the gas passes through the biomass material and dries the material, the exhaust outlet 34 extracts the oxygen deficient gas from the roasting reactor. The temperature of the drying gas may be in the range of 180 ° C. to 240 ° C., or other temperatures below the temperature threshold for causing a roasting reaction in the biomass material, eg, below 205 ° C. The temperature of the dry gas is lowest at the top inlet and increases by, for example, 5-10 ° C. at the lower gas nozzle 34. The evacuated dry gas is treated to remove moisture and other entrained liquids or solids from the gas, reheated and returned to the roasting reactor for use as a dry gas.

  The roasted gas processing unit 180 supplies oxygen-deficient gas to the lower region of the roasting reaction tank in which the biomass material roasts. This oxygen-deficient gas may have the same gas composition as that supplied by the dry gas processing unit. The roasted gas processing unit 180 supplies the oxygen-deficient gas at a temperature higher than a threshold temperature of, for example, 250 ° C. to 300 ° C. necessary for promoting the roasting reaction. The roasting gas is added from a nozzle 32 located with the top tray assembly configured for roasting. An additional inlet nozzle 32 for the roasting gas may be in the lower region of the reaction vessel. These lower nozzles add hot gases to ensure that the deposit of biomass material in the reaction vessel is maintained at or above a temperature that promotes the roasting reaction.

  In the embodiment of the roasting reactor shown in FIG. 23, there is no cooling zone and the roasting process continues as the biomass material flows down to the outlet of the reactor 162. Some cooling gas may flow countercurrently from the cooling screw 162 to the bottom of the reaction vessel 162. Furthermore, the cooling screw 162 may have a small flow of nitrogen gas at its discharge end. Nitrogen gas replaces the roasted gas containing organic compounds that are transported from the reaction vessel discharge into the cooling screw along with the roasted biomass material. If the organic compounds in the roasting gas are not removed, they can deposit on the cold surface of the cooling screw. In addition, the cooling screw may have an outer water jacket and a water passage through the center of the screw shaft. These water jackets and passages remove heat from the biomass material and cool the material. The hot water discharged from the cooling screw is circulated to the cooling tower and circulated to the cooling screw as cooling water.

  The gas extracted from the roasting process is removed from a single outlet 34 and flows directly into the roasted gas processing unit 180 through an insulated conduit. The extracted gas contains entrained organic compounds that deposit on surfaces that are cooler than the gas. By allowing the extracted gas to flow directly directly into the roasted gas processing unit, the risk of organic compounds accumulating on the surface of the conduit is reduced because the gas is in a short path to the gas processing unit 180. This is because a relatively high temperature is maintained. From gas processing unit 180, stream 181 is also sent to the combustor for further processing of the roasted gas, particularly condensed organic compounds removed from the roasted gas. The oxygen deficient gas generator 182 for the dry gas processing unit 178 and the roasted gas processing unit 180 may be a conventional nitrogen PSA plant that is commercially available. These plants generate sufficient amounts of gaseous nitrogen to supply dry gas processing units and roasted gas processing units.

  FIG. 24 is a process flow diagram illustrating an exemplary roasted gas processing unit 180. Compounds released from biomass during the roasting process include organic components of various molecular weights released during the roasting reaction. These organic components cause serious contamination of the equipment by tar deposits, especially when condensation occurs in an uncontrollable manner. In the roasted gas processing unit 180, the temperature of the gas extracted from the roasting reaction tank is lowered and the heavier organic compound is condensed, while the gas is more than the dew point temperature of water and the lighter organic compound. Is also maintained at a high temperature. Condensed organic components are formed into aerosols, mists or droplets in a gas stream. A gas stream containing condensed organic components flows to one or more dropout tanks or cyclone separators 204, where heavier components are separated from the gas stream. The heavier components fall to the bottom of the dropout tank or cyclone separator and flow to the collection tank 206. Component 181 from collection tank 206 may flow to a recovery boiler or other chemical recovery system.

  The roasting gas 200 extracted from the roasting reaction tank 162 is cooled in the heat exchanger 202, and the organic volatile material in the gas is condensed to form, for example, an aerosol or droplets. The cooled, roasted gas enters the cyclone separator 204 where the condensed droplets are separated from the gas. Other examples of separator 204 are devices that oxidize by-products, devices that catalytically convert by-products, devices that filter by-products from the gas stream, and use centrifugal force to separate particles from the gas stream. Including a flow separator such as a cyclone. Separator 204 is used singly or in combination in roasting gas treatment system 180. By-products separated by these devices may be further processed by separation, concentration or purification to make a usable product.

  The separated gas flows to the second heat exchanger 212, and the separated droplets flow to the condensate tank 206 as a liquid. Part of the liquid from the condensate tank is sprayed into the gas flowing from the heat exchanger 202 to the separator 204. Droplets sprayed into the gas facilitate the condensation of gaseous organic compounds from the gas stream. The liquid pump 208 may pressurize the condensate sprayed into the gas stream. A droplet spray nozzle 209 divides the liquid into droplets and sprays the droplets into the gas stream.

  The roasting gas flows from the cyclone separator to the second heat exchanger 212 and the third heat exchanger 214, and both heat exchangers raise the temperature of the gas to, for example, 250 ° C to 300 ° C. The third heat exchanger may receive thermal energy from the gas combustion combustor.

  The blower 216 increases the pressure of the roasting gas by, for example, 0.5 bar gauge when the gas 218 flows into the roasting reaction vessel. The roasting gas flows through the roasting gas processing unit 180 while being pressurized to the pressure in the roasting reaction tank.

  A heat transfer oil or condensate such as an organic compound circulates in the roasting gas processing unit, and the roasted gas exhausted from the roasting reaction tank is cooled in the heat exchanger 202 and the gas is purified in the separator 204. After that, the gas is heated in the second heat exchanger 212. The heat transfer oil or condensate is cooled in the heat exchanger 220 by cooling water flowing from 224 to 226 and to the cooling tower. The cooled liquid is temporarily stored in the fluid tank 222. The liquid pump 210 moves the liquid by liquid circulation in the roasting processing unit 180.

  The gas extracted from the drying section of the roasting reactor, such as the upper tray assembly, tends not to contain a large amount of high molecular weight organic compounds. The gas from the drying section includes oxygen-deficient gases, steam and water, and light volatile organic compounds that are difficult to condense on the surface of the reaction vessel. The gas extracted from the drying section need not be passed to the roasted gas processing unit 180. The dry gas processing unit 178 carries a separator and a condenser for removing water from the gas flow, a heat exchanger that raises the temperature of the gas to a required temperature in the roasting and drying unit, and the dry gas to the reaction tank. And a blower.

  The steam generated during drying can be exhausted to a combustor, exhaust stack or heat recovery system. The roasted gas generated during roasting may be combusted in a combustor, for example, with steam from a drying section, and the generated heat is used, for example, to predry the biomass.

  Although the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, the present invention is not limited to the disclosed embodiments and is intended to fall within the scope of the appended claims. It should be understood that variations and equivalent arrangements are intended to be included.

Claims (23)

A roasting reactor configured to perform a roasting process on biomass,
This reactor is
Inlet nozzle for injecting oxygen-deficient gas into the reactor;
A rotatable shaft extending vertically downward into the reaction vessel;
A stack of scrapers and trays extending from the top plate into the reactor;
A roasting chamber below the stack in the reactor and holding a deposit of biomass discharged from the stack;
A roasting gas exhaust outlet below the stack and above the upper surface of the biomass deposit in the reactor;
Biomass outlet in the lower region of the reactor;
Including
The gas temperature of the oxygen-deficient gas injected from the nozzle at the upper height of the reaction tank is lower than the gas temperature of the oxygen-deficient gas injected from the inlet nozzle at the lower height,
Each scraper is fixed to the shaft, rotates with the shaft, and is directly above the associated fixed tray;
Each tray is perforated to allow passage of gas but block passage of biomass, and has an opening through which the biomass passes and falls,
The stack includes a gas extraction chamber at a height below one of the trays and above one of the scrapers, the gas extraction chamber accepting gas passing through one of the trays and passed through the tray. Including a gas extraction port to exhaust gas,
The reaction tank according to claim 1, wherein the stack includes a plurality of lower scrapers and trays below the gas extraction chamber, and no gas extraction chamber is provided between the lower scrapers and trays.   The reaction vessel according to claim 1, wherein the shaft includes an adiabatic upper coupling configured to connect to a motor drive system external to the reaction vessel.   The reaction vessel according to claim 1 or 2, wherein each of the scraper and the tray is fixed together, and the fixed tray assembly and the scraper device are coaxial with the shaft of the reaction vessel.   The reaction according to any one of claims 1 to 3, wherein each of the trays is coaxial and has the same spread, each of the scrapers is coaxial and has the same spread, and the tray and the scraper are coaxial. Tank. Further comprising an isolation plate below the gas extraction chamber;
The isolation plate is coaxial with and coextensive with the tray and includes a walled chute, the walled chute extending through the gas extraction chamber to a scraper directly below the isolation plate. The reaction tank according to any one of 4.   The reaction vessel according to claim 5, wherein there is a gas distribution chamber directly below the isolation plate and above the scraper immediately below the isolation plate, having an inlet nozzle on the reaction vessel wall and receiving oxygen-deficient dry gas.   The roasting gas exhaust outlet is a single outlet, through which the roasting gas is substantially exhausted from the reaction vessel except for the gas flowing with the biomass through the biomass outlet. Item 7. The reaction tank according to any one of Items 1 to 6.   The roasting reaction tank according to any one of claims 1 to 7, further comprising an oxygen-deficient gas inlet nozzle on an outer wall of the reaction tank at a height lower than an upper surface of the biomass deposit. A method for biomass roasting using a roasting reactor with stacked trays, the method comprising:
Feeding biomass to the upper inlet of the reactor so that the biomass material is deposited on the upper tray of the vertical stack of trays in the reactor;
Sequentially dropping the biomass through the trays by passing the biomass through the opening in each tray and depositing the biomass on the lower tray;
Heating the biomass material with oxygen-deficient gas injected into the reaction vessel as it travels around each of the stacked trays of biomass;
Extracting the moisture-containing gas that has passed the biomass on the upper tray directly under each of the upper trays when the biomass is dried in the upper tray of the stacked trays;
When the biomass is roasting in the lower tray of the stacked trays, hold the gas along with the biomass until the biomass falls from the stacked trays into the biomass deposits in the reactor;
Extracting gas containing organic compounds volatilized by roasting of biomass from the gas outlet of the reaction vessel at a height between the stacked trays and biomass deposits; and roasting reaction of roasted biomass Draining from the lower outlet of the tank.   Further comprising circulating the extracted gas from the reaction vessel, removing volatilized organic compounds from the extracted gas to purify the gas, and supplying the purified gas to one or more of the stacked trays. The method of claim 9.   The method of claim 10, wherein purifying the gas comprises cooling the gas, condensing the organic compound, and separating the condensate from the gas.   The method according to claim 10 or 11, wherein the supply of biomass and the discharge of roasted biomass are continuous.   The method according to any one of claims 8 to 12, wherein the oxygen-deficient gas comprises nitrogen gas.   The method according to any one of claims 8 to 13, further comprising moving biomass around each tray by a scraper device corresponding to each tray.   The method according to any one of claims 8 to 14, wherein the oxygen-deficient gas is injected under a pressure of at least 3 bar gauge and the interior of the reaction vessel is under a pressure of at least 3 bar gauge. A method for roasting lignocellulosic biomass using a roasting reactor with stacked tray assemblies, the method comprising:
Continuously supplying the biomass to the roasting reactor so that the biomass material is deposited on the first tray assembly of the plurality of tray assemblies stacked vertically inside the reactor;
Heating the biomass material with an oxygen-deficient gas injected at a temperature below a threshold roasting temperature as the biomass falls sequentially through the drying tray in the tray assembly;
Extracting the gas flowing in each of the drying trays from the reaction vessel before the gas flows to the biomass on the next lower tray;
As the biomass sequentially falls through the roasting tray below the drying tray in the tray assembly, the biomass material is heated with an oxygen-deficient gas injected at a temperature above the threshold roasting temperature and roasted. Promoting the roasting reaction in the biomass on the tray;
When oxygen-deficient gas and biomass pass through multiple roasting trays, oxygen-deficient gas that passes through the roasting tray is contained in the reaction tank, and oxygen-deficient gas that has passed through the roasting tray is exhausted from the reaction tank. And discharging the roasted biomass from the lower outlet of the roasting reactor.   The method according to claim 16, wherein the threshold roasting temperature is in the range of 230C to 280C.   The method according to claim 16 or 17, further comprising purifying the exhausted gas by removing a volatilized organic compound and supplying the purified gas to the reaction vessel.   The method of claim 18, wherein purifying the gas comprises cooling the gas, condensing the organic compound, and separating the condensate from the gas.   20. A method according to any one of claims 16 to 19, wherein the oxygen-deficient gas comprises a substantial proportion of nitrogen gas.   21. The method according to any one of claims 16 to 20, further comprising moving biomass around each tray by a scraper device associated with each tray.   The method according to any one of claims 16 to 21, wherein the biomass is held in the reaction vessel for 15 to 60 minutes. 23. A method according to any one of claims 16 to 22 wherein the oxygen-deficient gas is injected under a pressure of at least 3 bar gauge and the interior of the reaction vessel is under a pressure of at least 3 bar gauge.

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