WO2014174351A1

WO2014174351A1 - Device for the solar thermal gasification of starting material containing carbon

Info

Publication number: WO2014174351A1
Application number: PCT/IB2014/000545
Authority: WO
Inventors: Peter Von Zedtwitz; Christina WIECKERT; Albert Obrist; Werner Voramwald; Aldo Steinfeld
Original assignee: Holcim Technology Ltd
Priority date: 2013-04-23
Filing date: 2014-04-15
Publication date: 2014-10-30
Also published as: AT514211B1; US20160068769A1; EP2989184A1; MX2015014837A; AR096044A1; AT514211A1; WO2014174351A8; EP2989184B1; AU2014259104A1

Abstract

The invention relates to a device for the solar thermal gasification of starting material containing carbon, comprising a solar reactor (1), which has least one, preferably a plurality of light-transmissive windows (2) for introducing concentrated solar radiation and a gasification chamber (9) having a preferably rectangular bottom and accommodating means for the starting material (21), wherein the accommodating means are formed by at least one preferably elongated drawer (7, 8, 20, 21, 22, 23) that can be moved in relation to the gasification chamber.

Description

Apparatus for the solar thermal gasification of carbonaceous feedstock

The invention relates to a device for solar thermal gasification of carbonaceous feedstock comprising a solar reactor with at least one, preferably a plurality of translucent window (s) for the introduction of concentrated solar radiation and a gasification chamber with a preferably rectangular bottom and receiving means for the feedstock.

The solar thermal gasification of carbonaceous feedstock serves the thermal decomposition of various starting materials under a controlled atmosphere for the production of a synthesis gas and is described, for example, in CH 692927 A5, WO 2008/027980 A1 or the article by P. v. Chem. Zedtwitz, A. Steinfeld: "The solar thermal gasification of coal - energy convergence efficiency and C0 ₂ mitigation potential" in Energy 28 (2.003) 441-456. Characteristic of solar thermal gasification is that radiation energy of an external source, preferably concentrated solar energy is used to produce the process heat required for the gasification reaction.

Simplified shown runs a gasification in a Solarre ^¬ actuator in the presence of water vapor according to the equation CH _x O _y + (ly) H ₂ 0 -> CO + (l + x / 2-y) H ₂ and in the presence of carbon dioxide gas after the Equation CH _x O _y + (ly) CO ₂ _-> (2-y) CO + (x / 2) H ₂ . However, these equations are a rough simplification of the actual prevailing conditions, with the following reactions in particular of particular importance: The steam gasification-according to the equation C _(gr ) + H ₂ O = CO + H ₂ is naturally superposed by the Boudouard Balance after the

CONFIRMATION COPY Equation 2 CO = C ( _gr > + C0 ₂ and side reactions in which, for example, methane is formed from carbon according to the equation C ( _gr) + 2 H ₂ = CH4 A reforming reaction proceeds according to the equation CH4 + H ₂ 0 = CO + 3H ₂ , where finally a shift of the CO / C0 ₂ equilibrium can be achieved with water vapor, for which the following equation CO + H ₂ 0 = C0 ₂ + H _{2 is} characteristic .. At temperatures below 550 ° C are graphite, methane , CO? And H ₂ 0 thermodynamically stable Only at much higher temperatures, a substantially uniform phase of H ₂ and CO can be achieved Temperatures of 1000 ° C and 1300 ° C are preferred, this one because of the higher temperature On the other hand, because of the thermal decomposition of any existing in the feed teerbildenen compounds, which is ensured only in this temperature range.

The quality of the synthesis gas obtained is of course essentially determined by the ratio H ₂ to CO and by the ratio C0 ₂ to CO. The shift of the ratio H ₂ to CO can be achieved at temperatures of 250 to 450 ° C in a particularly simple manner with water vapor (water gas shift). Otherwise, the option exists to gasify with a mixture of H ₂ 0 and C0 ₂ and thus influence the ratio of H ₂ to CO. Coal, biomass and various carbonaceous waste materials, such as contaminated soils, sewage sludge, filter residues and the like, have been proposed as feedstock for solar thermal gasification.

Carbon-containing wastes are often used as low-grade secondary fuels for the operation of clinker or cement kilns. However, the use of such lower-grade fuels is associated with a number of disadvantages. For example, the replacement of high quality leads Coal due to lower-grade fuels leads to a decrease in the adiabatic flame temperature in the sintering zone or main firing of 2300 ° C. to temperatures below 1900 ° C., with significant disadvantages in the clinker process already being observed at temperatures below 2100 ° C. A decrease in the flame temperature by 200 to 300 ° C by using low-grade fuels and in particular by using alternative fuels leads to a less favorable temperature profile over the longitudinal axis of the rotary kiln and usually leads to the ideal over a short range extending temperature maximum on a extends longer range at a lower temperature. The observed reduction in the quality of the clinker primarily affects the clinker reactivity.

In WO 2009/090478 A2, therefore, it has already been proposed to subject carbonaceous waste materials to solar thermal gasification and to supply the resulting high quality synthesis gas to increase the flame temperature of the burners of the main furnace of a clinker kiln. By conducting gasification using radiant energy, contamination due to combustion exhaust gases as in autothermal gasification is avoided, and the energy content of the syngas increases due to the absorbed radiant energy, thereby producing a much higher synthesis gas, which is characterized by a low amount of combustion gas per Energy unit distinguished. This synthesis gas is therefore suitable for raising the flame temperature and can be supplied to the burners in a corresponding subset in order to improve the clinker process and the temperature profile in the clinker furnace accordingly. For use on a large industrial scale, such as in connection with the utilization of waste materials in the clinker production, there is a difficulty in providing solar reactors with correspondingly large capacity. Fluidized bed reactors are unsuitable for particulate materials, their use would therefore require a large crushing effort. They are also eliminated for large capacities for design reasons, so that constructions with a stationary material bed must be used. In particular, there is the requirement to distribute the feedstock while minimizing the bed height on the largest possible area and to find ways to feed the reactor in a simple manner and in the shortest possible time with material and then discharge the ash just as easily and quickly.

The present invention therefore aims to develop a device of the type mentioned in that the above requirements are taken into account.

To achieve this object, the invention provides in a device of the type mentioned above, that the receiving means of at least one relative to .Vergasungskammer movable, preferably elongated drawer are formed. Preferably, a plurality of juxtaposed, along parallel movable tracks movable, preferably elongated drawers is provided. The one or more drawers serve to receive a stationary material bed and can according to the limited height of the solar reactor of example Im accordingly. be formed flat. Preferably, the at least one drawer has a height between the bottom and the upper edge of the side walls of less than 50 cm, in particular less than 40 cm. For example, the material bed may be at most 35 cm thick to ensure that the material is gasified over the entire layer thickness on the same day. If the layer thickness is too high, there may also be the risk that an insulating ash layer is formed on the upper side of the material bed, which prevents gasification of the underlying residual quantity.

The fact that the at least one drawer is movably arranged, this can be pushed out of the solar reactor in a simple manner and pushed into this again. In this way, the material loading and unloading can take place outside the solar reactor or outside the gasification chamber, so that loading and unloading together with operating personnel must penetrate into the because of the low height poorly accessible and also laden with hot and toxic atmosphere gasification chamber , The configuration is devised preferred in this context that the at least one deposition drawer between a loading located outside of the gasification chamber and Entla ^'and a working position located in the gasification chamber is slidable.

So that the interruption of the gasification process caused by the loading and unloading of the at least one drawer can be kept as short as possible, it is preferably provided that in each case a first and a second drawer are coupled together and arranged one behind the other in the longitudinal direction, so that the first drawer in the working position is when the second drawer is in the loading and unloading position, and the second drawer is in the working position when the first drawer is in the loading and unloading position. This allows a drawer to be unloaded and reloaded while the other drawer is in the gasification chamber. For the unloading and subsequent loading process there is enough time available, so that sufficient cooling the drawers done and the remaining after the gasification process ashes can be safely removed. Another advantage is that the drawers in the loading and unloading position can also be optionally repaired without the gasification process must be interrupted.

In order to avoid environmental damage caused by possibly spilled feedstock, a loading and unloading building is preferably arranged on both sides of the solar reactor, in which the drawers for taking the loading and unloading position are displaced. In order to automate the loading and unloading is further preferably provided that in the loading and unloading a plurality of the drawers each portal-like cross-loading and / or unloading devices are arranged, which are movable in the longitudinal direction of the drawers. In particular, the loading and unloading buildings are closed buildings so that the interior of the buildings can be controlled in terms of temperature conditions and atmospheric gas composition. This allows a controlled cooling of pushed out of the gasification chamber drawers and a controlled ventilation or ventilation of the building in order to deduct the possibly emerging from the ash gases.

In order to maximize the capacity of the drawers without impeding their displaceability, it is preferably provided that the drawers are elongated, with the longer extent in the direction of displacement. Here can be realized with a correspondingly dimensioned solar reactor lengths of example ^¬ as 10 0m, preferably 20-40m or more. Good mobility of the at least one drawer is ensured in accordance with a preferred development in that guide means, in particular rails for guiding the at least one drawer are provided along a displacement track.

In order to facilitate steam gasification in a simple manner, the drawers preferably have a bottom with openings for supplying water vapor. Particularly preferably, the openings connect the gasification chamber with a arranged below the bottom, integrated into the drawer distribution chamber.

The irradiation of the concentrated solar radiation into the solar reactor takes place, as already mentioned, via at least one transparent window. In view of the high temperatures, the at least one window is preferably made of quartz. The or the transparent window (s) is preferably assigned in each case a device for beam focusing in order to achieve the required concentration of the solar radiation. The beamforming can be done, for example, each by means of a CPC (Compund Parabolic Concentrator).

In general, care should be taken to ensure that the window or windows do not come into contact with the gaseous decomposition products of the gasification reaction, since they can attack the material of the windows. A preferred development therefore provides that the solar reactor above the gasification chamber has a further chamber, in which the concentrated solar radiation enters through the at least one translucent window. The concentrated solar radiation thus does not get directly into the gasification chamber, but in the mentioned further chamber. By the direct irradiation in the further Chamber is observed there an immediate increase in temperature, wherein the heat transfer takes place in the gasification chamber through the ceiling of the gasification chamber. A preferred embodiment provides in this connection that the gasification chamber and the further chamber are separated from one another by a blanket composed of high-temperature-resistant panels. The high-temperature resistant plates act here as radiation elements or radiation plates which radiate the thermal energy into the gasification chamber.

The said plates are usually available only in defined dimensions or can not be made arbitrarily large, with a corresponding support structure should be provided. Preferably, in this case a support structure for the high-temperature resistant plates is provided, comprising supporting means for supporting the support structure, which are arranged between the drawers. In particular, the support means in this case comprise at the bottom of the gasification chamber between the drawers extending, at a distance from the ceiling terminating partitions. The support means preferably comprise support columns supporting the partitions and carrying the support structure.

In the gasification chamber, temperatures of up to 1,300 ° C prevail during operation. There are therefore correspondingly temperature-resistant or refractory materials required. In particular, it should be avoided that metal parts of the radiation energy or the high temperatures are exposed. The radiation plates separating the gasification chamber from the further chamber are therefore preferably made of graphite, preferably with a SiC coating. The support columns are preferably made of SiC (silicon carbide). The drawers can be made of steel and covered with a suitable refractory material. In order to be able to push the at least one drawer back and forth between the working position and the loading and unloading position, a closable opening is preferably provided on two opposite sides of the solar reactor. When pushing out and pushing in the drawers there is a risk that ambient air enters the gasification chamber, which. can lead to the emergence of fire. This risk is particularly great when, as is preferably provided, there is a negative pressure in the gasification chamber relative to the environment. In order to minimize the entry of false air into the gasification chamber, the opening is preferably associated with a lock-type device, such as a curtain, in particular a metal curtain. · '

The invention will be explained in more detail with reference to embodiments shown schematically in the drawing. 2 shows a detailed representation of a section of FIG. 1, FIG. 3 shows a schematic representation of the drawer arrangement in a device according to FIG. 1, FIG. 4 shows a discharge device in a side view, FIG 5 shows a loading device in a side view, FIG. 6 shows the loading device according to FIG. 5 in a front view, FIG. 7 shows the device according to the invention in a reduced configuration, FIG. 8 shows the gasification chamber of the device according to FIG. 7 and FIG. 9 shows a cross-sectional view of FIG Device according to FIG.

In Fig.l a solar reactor is denoted by 1, which has at its top a plurality of windows 2 through which concentrated solar radiation can be introduced into the interior of the solar reactor 1. For the radiation concentration, a plurality of beam condensing devices 3 are provided, ^" in which solar radiation according to the arrows 4 enters from above. The incoming radiation is centered by reflection at parabolic or approximately parabolic surfaces and concentrated at the exit of the beam-splitting devices 3 and enters the solar reactor 1 via the windows 2. To the solar reactor 1 close on both sides in each case a loading and unloading buildings 5 and 6, in which subsequently explained in more detail drawers 7 and 8 are loaded with material and unloaded. In the position shown in Fig.l position is the drawer 7 in loading and unloading building 6 and the drawer 8 is located in the solar rektor. 1

2, the detail denoted by II in Fig.l is shown enlarged. It can be seen that the solar reactor has two chambers, namely a chamber 10 into which the concentrated solar radiation enters via the windows 2 and a gas chamber 10 sufficiently gas-tight separated from the chamber 10 by means of a cover 11 in which the solar thermal gasification of the feed material 12 takes place with the radiated from the chamber 10 thermal energy. The outer insulation of the solar reactor 1 is denoted by 13. The feedstock 12 is received within the gasification chamber in the drawer 8 in the form of a bed of material, the bed of material for protecting the drawer 8 preferably rests on a gravel bed 14. In the bottom of the drawer is a filling with water vapor and / or C0 ₂ gas distribution chamber 15, wherein steam or C0 ₂ gas can be supplied via the terminal 16. The bottom of the drawer 8 is provided with a hole pattern over which the water vapor contained in the distribution chamber 15 or the C0 ₂ gas can escape. The perforated grid preferably extends over the entire bottom surface of the drawer 8, so that an almost uniform loading tion of the material bed with steam and / or carbon dioxide gas succeeds.

The located in the loading and unloading position drawer 7 is the same structure as the drawer 8. To the. Drawers 7,8 now reciprocate between the working position and the loading and unloading position, the solar reactor 1 is provided with an opening 17 which is closed during operation by a vertically movable gate 18 and is opened after completion of .Vergasungsvorgangs. In order to guide the drawers 7,8 along the sliding track, guide rails 19 are provided.

In Figure 3 it can be seen that in the solar reactor 1, a plurality of drawers is arranged side by side, wherein two drawers are arranged in the longitudinal direction one behind the other and connected to each other. Only some of the drawers are shown in Fig. 3, namely the interconnected drawers 7 and 8, 20 and 21, and 22 and 23, of the two interconnected drawers each one in the working position, i. in the gasification chamber 9, and the other in the loading and unloading position, i. in one of the two loading and unloading 5 and 6, is. The other drawers are not shown for clarity. However, so many pairs of drawer can be used that the solar reactor 1 is used over its entire area. As a sliding drive for a drawer pair, a winch 24 is provided on the example of the drawers 22 and 23, which is anchored by means of an anchor 25 in the building 5.

As shown in Figure 3, the drawers are advantageously arranged so that each located in the loading and unloading position. Drawers of adjacent drawer rows are positioned in different loading and unloading buildings. In other words, the drawer of each second drawer row located in the loading and unloading position in the one loading and unloading building 5 and the corresponding drawer of each drawer rows between them in the other loading and unloading building 6 is positioned. This ensures that between the arranged in the respective loading and unloading 5 and 6 drawers remains a distance that facilitates the loading and unloading of the individual drawers.

The described arrangement of the drawers allows during the day a virtually uninterrupted operation of the solar reactor 1. While the feedstock located in the drawers 8, 20 and 22 is gasified in the gasification chamber, derived from a previous gasification process ash in the drawers 7, 23 and 26 are removed by means of unloading vehicles and the drawers 7, 23 and 26 are then filled by means of loading vehicles 26 with new material. After completion of the gasification process, the drawers 20 and 22 are moved into the loading and unloading building 6 and the drawer 8 in the loading and unloading building 5, wherein the respective coupled drawers 7, 23 and 26 simultaneously enter the solar reactor 1, where now new gasification process can begin. At the same time, the drawers 8, 20 and 22 in the respective loading and unloading. unload buildings 5 and 6 and then load them again. The described sequence can be repeated as often as desired.

FIG. 3 also shows a gas outlet 27 which is connected to the gasification chamber 9 of the solar reactor 1 and which is used to move the gas chambers between the valves during the displacement of the drawers. Beitsposition and the loading and unloading in the gasification chamber 9 to suck in penetrating false air.

4, an unloading vehicle 28 is shown, which serves to unload or collect the ash remaining in the drawer 21 after the gasification process. The vehicle 28 has a for this purpose. Suction nozzle 29, which has at its end a extending across the width of the drawer nozzle. The vehicle 28 has a width exceeding the width of the drawer gauge and therefore (as shown in Figure 6 based on the loading vehicle 26) can be positioned with its suction nozzle on the drawer and extend the drawer in the longitudinal direction. The vehicle 28 has a sump in which the sucked ash is collected.

In FIGS. 5 and 6, the loading vehicle 26 is shown having a storage container for the feed to be deployed and a material distribution device for uniformly spreading the material over the entire width of the vehicle. The application is preferably carried out by means of driven conveying means, the drive of which is coupled to the locomotion drive of the vehicle 26, so that the output quantity is proportional to the travel speed of the vehicle. As can be seen in Fig. 6, the track width of the vehicle exceeds the width of the drawer 21, so that there is a drawer portalartig cross-construction.

In Fig.7 a reduced configuration of the solar reactor 1 is shown, the gasification chamber 9 only two drawers 8 'and 20' receives. Apart from that, however, the embodiment according to FIG. 8 corresponds to the embodiment according to FIGS. 1-3. The drawers are shown in an empty condition and it can be seen that the bottom of the drawers have a variety of Has openings 33 in the form of a hole pattern through which the water vapor and / or the carbon dioxide gas can escape from the distribution chamber 15. Furthermore, the bottom of the drawers carries a grid-like subdivision 31, which forms a plurality of shallow trays for receiving the gravel bed 14.

In Figure 7 it can be seen that the roof 30 of the solar reactor is formed segmented. Furthermore, 9 opening openings 32 are shown in the gasification chamber, which serve the introduction of carrier or purge gas.

In Figure 8, only the lower part of the solar reactor 1, that is, the gasification chamber 9 is shown. The discharge opening 34 for withdrawing the synthesis gas formed during the gasification reaction can now be seen. This discharge opening 34 is located above the drawers in the hot reactor space. This ensures that any tar-forming substances emerging from the material to be gasified are thermally decomposed into non-tar-forming synthesis gas components such as CO, H _2, etc. before they leave the reaction space. Furthermore, between the two drawers 8 'and 20', a partition wall 36 is provided, which carries Abstützsäulen 37, which in turn carry a lattice-shaped support structure 35. The support structure 35 serves, as shown in Figure 9, the support of high temperature resistant plates 38, which form the ceiling 11.

Claims

Claims:

1. An apparatus for solar thermal gasification of carbonaceous feedstock comprising a solar reactor having at least one, preferably a plurality of translucent window (s) for the introduction of concentrated solar radiation and a gasification chamber with a preferably rectangular bottom and receiving means for the feedstock, characterized in that the Receiving means of at least one relative to the gasification chamber movable, preferably elongated drawer (7,8,20,21,22,23) are formed.

2. Apparatus according to claim 1, characterized in that a plurality of juxtaposed, along parallel movable tracks movable, preferably elongated drawers (7,8,20,21,22,23) is provided.

3. Apparatus according to claim 1 or 2, characterized in that the translucent windows (2) are each assigned a device for beam focusing (3).

4. Apparatus according to claim 1, 2 or 3, characterized in that the at least one drawer (7,8,20,21,22,23) located between a outside of the gasification chamber (9) loading and unloading position and one in the gasification chamber (9) working position are displaced.

5. Device according to one of claims 1 to 4, characterized in that guide means, in particular rails (19) for guiding the at least one drawer (7,8,20,21,22,23) are provided along a displacement track.

6. Device according to one of claims 1 to 5, characterized in that the at least one drawer (7,8,20,21,22,23) has a bottom with openings (33) for supplying water vapor and / or carbon dioxide gas. ,

7. The device according to claim 6, characterized in that the openings (33) connect the gasification chamber (9) with a arranged below the bottom, in the drawer (7,8,20,21,22,23) integrated distribution chamber (15) ,

8. Device according to one of claims 1 to 7, characterized in that the solar reactor (1) above the gasification chamber (9) has a further chamber (10), in which the concentrated solar radiation through the at least one translucent window (2) occurs.

9. Apparatus according to claim 8, characterized in that the gasification chamber (9) and the further chamber (10) by a high temperature resistant plates (38) composite ceiling (11) are separated from each other.

10. The device according to claim 9, characterized in that a support structure (35) for the high temperature resistant plates (38) is provided, comprising supporting means for supporting the supporting structure (35) between the drawers (7,8,20, 21,22 , 23) are arranged.

11. The device according to claim 10, characterized in that the supporting means at the bottom of the gasification chamber (9) between the drawers (7,8,20,21,22,23) extending, at a distance from the ceiling (11) ending partition walls (36 ).

12. The device according to claim 10 or 11, characterized in that the support means on the partitions (36) supporting the support structure (35) supporting support columns (37).

13. Device according to one of claims 4 to 12, characterized in that in each case a first and a second drawer (7,8,20,21,22,23) are coupled together and arranged one behind the other in the longitudinal direction, so that the first drawer in the Working position is when the second drawer is in the loading and unloading position, and the second drawer is in the working position when the first drawer is in the loading and unloading position.

14. Device according to one of claims 4 to 13, characterized in that on both sides of the solar reactor (1) in each case a loading and unloading building (5,6) is arranged, in which the drawers (7,8,20,21, 22,23) are displaceable for taking the loading and unloading position.

15. The apparatus according to claim 14, characterized in that in the loading and unloading buildings (5,6) a plurality of the drawers (7,8,20,21,22,23) each portal-like cross-loading and / or unloading ( 26,28) are arranged, which are movable in the longitudinal direction of the drawers (7,8,20,21,22,23).