WO2011079948A1

WO2011079948A1 - Device for continuously converting biomass and system for obtaining energy therefrom

Info

Publication number: WO2011079948A1
Application number: PCT/EP2010/007964
Authority: WO
Inventors: Bernd Schottdorf
Original assignee: European Charcoal Ag
Priority date: 2009-12-29
Filing date: 2010-12-29
Publication date: 2011-07-07
Also published as: DE102009060733A1; DE102011011521A1

Abstract

The invention relates to a reactor battery (100; 200) for continuously converting biomass, comprising a plurality of cells (102; 202), each comprising a feed zone (208) for drying, degassing and converting the biomass into a combustible gas, and a flame zone (206) for converting the biomass into a solid conversion product, wherein the conversion takes place pyrolytically in the feed zone of each cell (102; 202).

Description

Apparatus for the continuous conversion of biomass and system for 5 energy production therefrom

The present invention relates to a reactor battery for the continuous conversion of biomass and a system for generating energy from biomass. DE 10 2005 038 135 B3 discloses an apparatus for the continuous production of charcoal in a moving bed of wood or other biomass. The apparatus comprises a wood or other biomass feed device, a well receiving, drying, degassing and carbonizing the moving bed of wood or other biomass, one or more air supply means located at the bottom of the well 5 and one at the bottom of the well arranged grid. The charcoal passing through the grate is collected below it in a water basin, cooled, conveyed out of the water basin and must be dried before further use. o FR 2 677 661 describes a plant for the carbonization of wood to coal without smoke emission. The coal is automatically discharged from the plant after carbonation. For carbonization several separate stoves are used. The floors of the ovens are inclined to a bottom flap. When these bottom flaps are opened, a batch of charcoal from the ovens can slide into a common container. The air supply of the individual ovens leads to several places in the ovens and is controlled by closing mechanisms. Carbonisation produces smoke in a chimney EP 153 982 A1 describes a device with a combustion chamber for the batch production of charcoal. For the device, a controllable ventilation opening is provided which directs air through a two-pipe system in the upper region of the combustion chamber. In the combustion chamber resulting smoke is dissipated in the lower 5 area of the combustion chamber and blown out through a fireplace. The EP 153 982 AI also describes the use of a grid in the bottom of the combustion chamber, as well as several openings in the ground. This arrangement serves to provide and burn off an additional fuel which treats the raw material to be processed in the combustion chamber in a high temperature refining step

The object of the present invention is to provide an energy-efficient and simple device for the continuous conversion of biomass and a system for obtaining energy from biomass. According to the invention, this object is achieved by the subject matter of the independent claims. Variants and preferred embodiments of the invention will become apparent from the claims, the following description and the drawings.

The reactor battery according to claim 1 for the continuous conversion of biomass comprises a plurality of cells each having a supply area for drying,

Degassing and converting (a portion of) the biomass to a combustible gas and a flame area to convert the biomass to a solid conversion product. In this case, the conversion takes place pyrolytically in the feed region of each cell.

5

The feeding area of a cell takes e.g. a moving bed of biomass, in particular wood, and is subdivided into an upper section for drying, a middle section for degassing and for pyrolytic conversion of the biomass. A lower portion of the cell forms a flame zone for charring the biomass into a solid conversion product, especially charcoal. Under the

Flame region may be arranged, for example, a grid, which supports the moving bed and which is permeable to the solid conversion product down. Continuous conversion offers time advantages over batch or batch processes. In such processes, a portion of biomass is first fully processed before the next position can be processed. If necessary, the system must always be restarted. However, the device according to the invention enables a continuous operation; So also when supplying biomass and the discharge or removal of conversion products.

In the feed area, moist biomass is largely dehumidified or dried by charring hot gases upstream of the charring in the flame area. This increases the calorific value of the solid conversion product. The temperature in the feed area can be between 500 - 900 ° C. Such temperatures allow for largely oxygen-free conditions pyrolytic decomposition of biomass. Pyrolysis is generally the term for the thermal cleavage of organic

Compounds in which high temperatures (500-900 ° C) break up bonds within large molecules. Mostly this happens under oxygen exclusion (anaerobic) to prevent combustion. One speaks also of a Verschwelung.

Depending on the flow rate of the biomass moving bed, the pyrolytic transformation takes place more or less completely (partial pyrolysis). At longer residence time more bicimbaies gas is generated. With shorter residence time, more unconverted biomass reaches the flame area.

The arrangement of a plurality of cells, each carrying out the processes described above, in a reactor battery enables improved process control, in that the oxygen or air supply can each be adjusted to a relatively small range. Thus, pyrolysis or partial pyrolysis and charring can be reliably controlled for each cell. For larger undivided reactors, however, there may be unregulated, local chimney and combustion effects that hinder the desired teilpyrolytischen decomposition effect.

According to a development, the reactor comprises an adjustable air supply per cell. Preferably, the supply of air from below the grid is such that a desired amount of air enters the flame area of each cell. In the flame area the biomass is charred in substoichiometric oxygen supply or relative lack of oxygen, for example to charcoal. At appropriate temperatures, partial combustion of volatiles of the biomass occurs while carbon (eg, charcoal) falls down through the grid.

5

The released waste heat increases the volume of the combustion gases, which are driven so convectively in the cell upwards and dry and degas the biomass in the feed area. The oxygen supplied via the air supply is almost completely consumed for decomposition in the flame region. The upward driven o combustion gases are thus largely free of oxygen or oxygen and thus create temperatures and conditions for a pyrolytic or teilpyrolytische conversion of biomass in the feed.

Conventional carbonation plants, in contrast, introduce air or oxygen at several points into a combustion chamber in such a way that, although in a large combustion chamber

Combustion chamber, a carbonization is easily controllable, but due to the oxygen, no simultaneous pyrolytic, i. essentially oxygen-free, conversion takes place. o According to a development, the reactor battery comprises a control device for

Measuring the temperature, in particular the Abgasicmperaiur, in individual lines or in the collected exhaust gases in the reactor battery, and for controlling the amount of air supplied via the air supply. If the temperature is measured in individual cells, this can serve as a control variable for the control device in order to control the air supply to the individual cells in such a way that a desired temperature profile or a temperature profile over the feed region of each cell is maintained. o A reactor battery can also be partially started or stopped by cell-controlled air supply. In addition, a desired temperature gradient can be generated by cell-controlled air supply. For example, an elevated temperature may be required in the outer cells of the reactor battery to compensate for heat losses to the environment. In addition, so too in one Part of the cells of the reactor battery conditions for higher gas production and in another part of the cells conditions for a higher production of solid conversion products can be set.

There are embodiments in which the reactor battery comprises a central exhaust gas removal device. This includes manifolds that lead from upper portions of the individual cells to a collection tank and / or chimney. The temperature can be detected, for example, centrally to the collected exhaust gases to obtain a common control variable for the control device for controlling all air supplies.

According to a development, the reactor battery comprises a supply device for the continuous supply of biomass, in particular wood chips. The feeder has e.g. a rotary valve on to promote biomass largely under exclusion of gas continuously into the individual cells. The supply device may also comprise distributor tubes which convey the biomass from a biomass store via the rotary feeder to the individual cells.

According to a development, the reactor battery comprises one discharge device per cell in order to discharge the solid conversion product. There are embodiments with headers, which lead starting from the areas of the reactor battery, which are below the grid of each cell, in a slight gradient to a gas-tight container in which the solid conversion product is taken up and cooled.

There are also embodiments in which the discharge device can be designed as a rotary valve, with which the solid conversion product is discharged continuously or batchwise, and which is arranged in or on the cell.

Advantageously, the amount output is then controlled by simple means,

for example, by means of a filling height switch, which determines the operation for a defined period of time and thus for a defined discharge volume when a certain filling level or capacity is reached. The discharge device can be arranged below a collecting funnel, which in turn is arranged below a cell or in the lower region of a cell. In the collection funnel can also be a Nachverschwelung done. Between collection hopper and discharge device can also be interposed a manifold.

According to a further development, the reactor battery is thermally insulated on its outer side. There are also embodiments in which the cells are designed in their structure or arrangement so that the reactor is a teilpyrolytische conversion of biomass into a solid conversion product and a combustible gas.

According to a development, the individual cells can be thermally isolated to the outside. Preferably, the individual containers are each completely insulated.

For example, rockwool has been found to be suitable, but other suitable insulating materials can be used.

According to a development, the cells may each comprise, individually or jointly, a downstream fluid distribution device. Also, the

Fluid distribution device integrally formed in the cells. There are

Embodiments in which the fluid distribution device comprises a mixing device arranged in a mixing chamber and a moistening device.

For example, the mixing device can be designed as a mixer or stirring iron. The mixer may be below the reactor space in a mixing chamber

be ai.gcurdiiei. In the mixing chamber, the resulting charcoal is sprayed / moistened or mixed and mixed with water via spray nozzles arranged in the walls or in the ceiling of the mixing chamber. Thus, the mixer can allow a defined supply of water into the charcoal, so that minus any evaporating water, a desired suitable water content, for example

15 to 25%, in particular from 18 to 20%, can be achieved in the charcoal.

Advantageously then no further combustion or cooling in additional cooled or coolable containers is required. The conversion product, such as charcoal, can be immediately portioned and packaged. Also needs a downstream

Discharge conveyor not necessarily be made fireproof.

According to a development, the reactor battery may also comprise an adjustable exhaust gas removal device per cell. For example, at the top of a Cell can be arranged an exhaust pipe for the removal of gases from the reactor space of a cell, which is provided with a fan.

According to a development, the reactor battery or each individual cell may comprise a control device for measuring the pressure, in particular the pressure of gases in the individual cells and / or in the reactor battery, and for controlling the amount of exhaust gas discharged via the exhaust gas removal device. The speed of the fan can be controlled by the pressure conditions in the upper region of the reaction space. Only through this speed control o the entire Verschwelungsprozess is controllable.

Dehumidification or drying of the supplied biomass can also be controlled via the control of the exhaust gas removal, so that the process for biomass of different composition (eg variable water content)

5 improved is adjustable.

According to a development, the reactor battery is modularly formed from individual reactor cells with a rectangular cross-section. Such individual reactors can be assembled in a particularly simple manner by juxtaposing them with a likewise cuboid reactor battery. A honeycomb structure is also possible. Such a modular design allows to add or remove individual cells. In this case, the cells of the reactor battery are single-walled and double-walled. 5 According to a development, the individual cells are overseas containers

designed or arranged therein. Such container batteries are inexpensive and can consist of one or more cells. Also, the individual containers are easy to transport by conventional means and can be assembled on site. These can be set upright or transversely and via a suitable o suitable connecting means or compound, for example a scaffold, a

Frame, T-beam, screws, welded joint, etc. are interconnected. Each container can be a cell with a feed hopper in one

Rotary valve opens, a reaction space or reactor space below the rotary valve, a discharge funnel below the reactor chamber, which opens into a rotary valve, a mixer below the above

5 rotary valve in which the resulting charcoal with water

sprayed / moistened and mixed.

When a reactor battery is made by a common outer wall of the reactor and several intermediate or partition walls, the cells may be designed outwardly and to one another in a single-walled manner. This variant is more material-saving.

A biomass energy recovery system comprises a reactor battery according to the invention, a combined heat and power plant for burning the combustible gas, and a press for pelleting or briquetting the solid conversion product, especially charcoal.

According to a development, the system also includes a kiln for burning the pressed conversion product. The furnace, the reactor battery o and / or the pelleting or briquetting can also separated öiigcOidiic ^'be i.

Such a system allows a high energy yield of the biomass with high spatial flexibility, since the gases resulting from the conversion, e.g. can be used on site in a cogeneration plant, while the solid conversion product is easily transported and metered by pelleting or briquetting and in remote plants, for example. can be used in households.

Hereinafter, further embodiments of the invention with reference to schematic o shear drawings are explained in more detail. Showing:

Fig. 1 shows a schematic view of an embodiment of the reactor battery according to the invention Fig. 2 shows a partially broken side view of an embodiment of the reactor battery according to the invention

Fig. 1 shows a reactor battery 100 according to the invention for continuous

5 conversion of woodchips. The reactor battery 100 here comprises seven by six individual reactors, hereinafter referred to as cells 102, which are arranged in a cuboid. The reactor battery is surrounded by a common reactor outer wall 104. For separating the individual cells 102 from each other, six transverse and five longitudinal dividing walls 106 run within the reactor outer walls 104.

All cells 102 are continuously supplied wood chips, as indicated schematically by the arrow 108 in Fig. 1. Wood chips from a wood chip storage are (not shown) via pipes to a rotary valve and from there via 5 distribution pipes (not shown) to the individual cells.

In a teilpyrolytischen conversion arise in the cells in addition to non-combustible and flammable gases with high calorific value, e.g. Methane, carbon monoxide and hydrogen, as well as solid conversion products, e.g. Charcoal. The gases are removed at the top of each cell, as schematically indicated by arrow 1 10 in FIG. 1, and are collected, compressed and stored via pipes (not shown) or else used thermally (combustion). The solid Ümwandiungs- products lead manifolds 112 below each cell, if necessary gas-tight in one

Collecting container (not shown). The reactor outer wall 104 is thermally insulated with rockwool or other suitable insulating material. Within the reactor battery wall heat exchange takes place through the transverse and partitions 106 therethrough. The cells 102, however, remain materially isolated from each other. This causes lower heat losses compared to thermally decoupled cells. Each cell 102 is provided with an o controllable / adjustable / adjustable air supply, the z. B. is controllable via a the exhaust gas temperature sensing control. The control can take place cell by cell (locally) or by reactor (globally). It is also possible to make a local manual or automatic presetting (eg border cells other than central Cells) and in operation then a globally controlled air supply control - but cell by cell - make.

FIG. 2 shows a reactor battery 200 according to the invention which, like the reactor battery 100 shown in FIG. 1, comprises a plurality of reactors, which are referred to below as cells 202. In contrast to the cells 102 in FIG. 1, the cells 202 are each provided with their own cell wall 204a, 204b. Between cell walls 204b of juxtaposed cells 202, a schematic distance is visible in FIG. 2, but this does not actually have to be present. The cells are as close to each other as possible to allow good heat exchange between the cells 202. Outer cells in the reactor battery 200 are thermally insulated at their outer cell walls 204a, but not at their inner cell walls 204b. A honeycomb structure can improve the thermal properties (smaller outer surface).

In the cells shown in Fig. 2, two conversion regions are distinguishable. In a lower area, the flame area 206, woodchips are charred with bottom stoichiometric oxygen supply to charcoal. The resulting hot gases rise up the supply area 208. The hot gases themselves contain little or no oxygen, as this is almost used up in the charring. In the feed area, these hot gases cause drying, degassing and pyrolytic or partially pyro- lytic conversion of wood chips to combustible gases at temperatures of 500 to 900 ° C. This so-called wood gas essentially comprises hydrogen, carbon monoxide, methane, carbon dioxide and nitrogen.

In the drying of biomass resulting water vapor "shifts" the pyrolysis slightly towards a gasification, whereby more combustible gas can arise. However, if too much water is contained in the biomass, the heat required to dry the biomass can lower the temperature below the temperature necessary for pyrolysis. The dehumidification or drying can be controlled via the control of the air supply, so that the process for differently composed biomasses (eg variable water content) is adjustable. The air required for charring (with oxygen) in the flame area passes through regular, controllable or adjustable air supply lines, indicated schematically by the arrows 210, in each cell. The cell walls 204b thereby prevent uncontrolled combustion channels 212 between the cells 202. If the cells 202 of the reactor battery 5 200 combined into a single large combustion chamber, so could air from the air supply 210 of a cell and air of an adjacent air supply 210 to a location in this large combustion chamber flow and form local combustion channels 212 in which woodchips would burn completely, thereby essentially producing only combustible and non-combustible gas but no charcoal, and the process would be disturbed. Controlled partial pyrolytic decomposition would not be possible.

In general, a grid 214 supports the reaction material, i.e. the biomass. Below the grid 214, air is passed through e.g. Feeder tube 210 is approximately centrally supplied to a respective single cell 202. The amount of air is precisely controlled and z. B. 5 regulated by the temperature of an exhaust stream. Directly above the lattice 214, under the conditions of relative lack of oxygen, the biomass (wood, etc.) or carbonization of the biomass takes place with substoichiometric oxygen supply. The relative lack of oxygen due to restricted air supply leads to the combustion (or partial combustion) of the volatile constituents of the reaction material, while the solid carbon in the form of carbon atoms falls down through the grid 214 out of the cell. The heat generated in this conflagration fire leads to the expansion of the resulting combustion gases, so that they are driven upwards in the reactor. About 0.5 to 0.8 meters above the grating 214, the oxygen is consumed by the plating process. 5 Below this range is thus the oxygen zone, above starts the

Pyrolysis.

The now largely oxygen-free reaction gas, which contains mainly nitrogen and C0 ₂ leaves the oxygen zone up at a temperature of about 500 to 600 ° C. Biomass that reaches on this way from above into this area o contains virtually no more water. It is heated under these conditions and wood gas is expelled pyrolytically. This continues to rise and up can be led out of the cell 202 led into a combined heat and power plant or the like and used for energy or as district heating.

In another embodiment, not shown, of the invention are the

5 individual cells 102 as upright arranged container, for example

Overseas container, trained. Overseas containers are typically sea freight containers and ISO containers, which are 20 and 40 feet long and 8 feet wide. Such overseas containers are not only ideal for transport on container ships, but also for transport by truck or rail. With o use of overseas containers they can be thermally insulated on all outer walls and then be coupled together, for example, via a skeleton, screwed or otherwise suitably connected. In this case, then only a small or no heat exchange through the transverse and partitions therethrough. 5 Each container contains one cell. Each cell may have an upper feed hopper which opens into a rotary valve, a reaction space below the

Rotary valve, a discharge funnel below the reaction chamber, which opens into a rotary valve, a mixer below the aforementioned

Rotary valve in which the resulting charcoal with water

o sprayed / moistened and mixed.

Furthermore, an exhaust pipe may be arranged in the upper region of each cell, which is coupled to a fan, wherein the rotational speed of the fan is controlled by the pressure conditions in the upper region of the reactor space.

5

The individual overseas containers or the cells arranged therein are continuously or batchwise supplied wood chippings or other biomass via a feed device, for example via a feed conveyor, directly or via distribution pipes. Within each cell, the biomass is in the

o Feed funnel or collection funnel fed in and collected there. At the bottom

At the end of the feed hopper, an opening and / or a rotary feeder is arranged, via which the biomass is introduced or transported further into a reactor space arranged underneath. In the reactor room then takes place a previously described teilpyrolytischen and / or pyrolytic conversion and charring of the biomass. The reactor space is coupled to an exhaust pipe for the discharge of exhaust gases. The exhaust pipe is in turn coupled to a fan.

In this case, via an exhaust gas removal device, a pressure measurement in the reactor chamber at the reactor end, preferably in the upper region close to the feed hopper via a correspondingly suitable sensor device. As a function of the measured pressure, in particular negative pressure, the exhaust gas removal device controls the speed or speed of the fan and thus the amount of exhaust gas discharged to the outside. Only through this speed control, the entire Verschwelungsprozess is controllable.

The dehumidification or drying of the biomass, which has already been described above, can be further controlled via the control of the exhaust gas removal, so that the process for biomass of different composition (eg, variable biomass)

Water content) is adjustable.

The lower end of the reactor space is provided with a collecting funnel and comprises a funnel opening in which a further rotary valve can be arranged. Within the Sammeuri here, a Nachverschweiung can take place. By means of the rotary valve solid conversion products are transported in a downstream mixing chamber. With the rotary valve, a continuous or batch discharge from the collecting hopper can take place. For example, a filling height switch may be provided which defines the rotary feeder for a defined

Period of time turns on, so that a defined discharge volume is discharged.

The mixing space comprises a mixer, for example a stirrer or a similar suitable device, which mixes the introduced conversion products. In an appropriate position are in the ceiling and / or in the walls of the mixing room

Provided spray nozzles, which direct a defined amount of water to the conversion products or spray. Depending on the desired water content of the conversion product, for example 18 to 20%, and its feed rate, the amount of water sprayed accordingly vary. In this case, the spray water also cools the conversion product so that it can be further processed, for example transported, packed or portioned.

The moistened conversion product may fall out of the lower end of the container, which may comprise a previously described grid, and / or be removed via a conveyor belt disposed inside or outside the container. Since the conversion product has cooled down, the downstream discharge conveyor belt does not necessarily have to be fireproof.

In a further example arrangement, not shown, several, for example five, containers with a common conveyor belt for the supply of biomass in the individual containers and with a further common conveyor belt for the removal of the moistened charcoal may be connected in series. The discharge conveyor belt does not have to be fireproof, since the charcoal is discharged through the

Moisten already cooled.

Other aspects and variations of the invention will become apparent to those skilled in the art from the appended claims.

Claims

claims

1. Reactor battery (100; 200) for the continuous conversion of biomass, with:

5 a plurality of cells (102; 202) each having a supply area (208) for

Drying, degassing, and converting the biomass to a combustible gas and a flame zone (206) to convert the biomass to a solid

Include conversion product, wherein

the conversion is pyrolytic in the feed region (208) of each cell (102; 202) o.

A reactor battery (100; 200) according to claim 1, having an adjustable air supply (210) per cell (102; 202). 5

3. Reactor battery (100; 200) according to claim 2, with a control device for measuring the temperature, in particular the temperature of gases in individual cells (102; 202) and / or in the reactor battery (100; 200), and for controlling or Control the amount of air supplied via the air supply (210). 0

4. Reactor battery (100; 200) according to one of the preceding claims, with a feed device for the continuous supply of biomass, in particular wood chips.

A reactor battery (100; 200) according to any one of the preceding claims, comprising a discharge means (1 12) per cell (102; 202) for discharging the solid conversion product.

6. Reactor battery (100; 200) according to claim 5, wherein the discharge device comprises collecting pipes (1 12) for the collected discharge of the solid conversion Pro duct.

7. reactor battery (100; 200) according to claim 4 or 5, wherein the

Discharge a rotary valve for continuous or batchwise Comprising discharging the solid conversion product disposed in or on the cell (102; 202).

8th . Reactor battery (100; 200) according to one of the preceding claims, which is thermally insulated to the outside and / or in which the cells (102; 202) in their

Structure or arrangement are designed so that it performs a teilpyrolytische conversion of biomass into a solid conversion product and a combustible gas.

A reactor battery (100; 200) according to any one of the preceding claims, wherein: o the individual cells (102; 202) are thermally insulated outwardly.

10. Reactor battery (100; 200) according to one of the preceding claims, in which the cells (102; 202) in each case individually or jointly comprise a downstream fluid distribution device arranged in a mixing chamber.

5

A reactor battery (100; 200) according to claim 10, wherein the

Fluid distribution device is integrally formed in the cells (102, 202).

12. reactor battery (100; 200) according to claim 10 or 1 1, wherein the

0 Fluidverteilvorrichtung comprises a mixing device and a humidifying device.

13. Reactor battery (100; 200) according to one of the preceding claims, with an adjustable exhaust gas removal device per cell (102; 202).

5

14. Reactor battery (100; 200) according to claim 13, with a control device for measuring the pressure, in particular the pressure of gases, in the individual

Cells (102, 202) and / or in the reactor battery (100, 200), and for controlling the amount of exhaust gas discharged via the exhaust gas discharge device.

0

15. A reactor battery (100; 200) according to any one of the preceding claims constructed modularly from individual reactors (202) of rectangular cross-section.

A reactor battery (100; 200) according to any one of the preceding claims, wherein the cells (102; 202) are configured as overseas containers or disposed therein.

17. System for obtaining energy from biomass, in particular wood, with:

a reactor battery (100; 200) according to one of claims 1 to 16

a combined heat and power plant for combusting the combustible gas and a press for pelleting the solid conversion product, in particular charcoal.

A system according to claim 17, including a kiln for burning the solid, pressed conversion product.