WO2001084041A1

WO2001084041A1 - Tank system for bulk material which can be loaded with a combustible gas and which consists of fine to minute solids, and a device for discharging the bulk material

Info

Publication number: WO2001084041A1
Application number: PCT/DE2001/001631
Authority: WO
Inventors: Peter NAVÉ; Walter Kroy
Original assignee: Ludwig Bölkow Stiftung
Priority date: 2000-05-02
Filing date: 2001-04-30
Publication date: 2001-11-08
Also published as: EP1278986A1; DE10021289A1; DE10191681D2; AU2001262054A1

Abstract

The invention relates to a tank system for bulk material which can be loaded with a combustible gas, for example filled with hydrogen and which consists of fine to minute solids and to a device for discharging the bulk material. According to the invention, the filling volume of the tank (1) is subdivided into two separate sections (5, 6) which are hermetically sealed from one another, in such a way that the volumes of said sections can vary alternately in a reciprocal manner, between the value «approximately zero» and the approximately maximum filling volume of the tank (1), and that the tank (1) is connected to a device for discharging the bulk material, which allows the discharged bulk material to be returned to said tank (1).

Description

description

Tank system for bulk goods consisting of small to very small solids, which can be loaded with a combustible gas and a device for unloading the bulk goods.

The invention relates to a tank system according to the preamble of claim 1.

One of the storage possibilities for hydrogen on board electric vehicles equipped with fuel cells is the adsorption of hydrogen on and in so-called nanotubes, a modification of graphite which is related to the “fullerene” spherical large carbon molecules. In order to be able to use the adsorbed hydrogen in the fuel cells , it must be desorbed at a preferably elevated temperature and then separated from the emptied nanotubes.As the production of the tube material is complex and no significant cost reductions are to be expected, the tubes must be collected for reuse after they have been discharged, even if the tubes are mechanically relative are resistant, they still have to be handled very gently so that as few of them break as possible during unloading.

The invention is therefore based on the object, in the context of the tank system according to the invention, to initially propose a tank which allows the unloaded bulk material to be taken up gently and also very space-saving, while the bulk material to be unloaded is removed from the same tank.

This object is generally achieved by the characterizing part of patent claim 1, and in particular by the characterizing parts of patent claims 2 to 4. While the bulk material loaded with a combustible gas is removed from the tank, the unloaded bulk material can flow back into the same tank, since this has two hermetically separated departments, which are separated by the separating element - a highly flexible membrane or a plunger - with regard to their volumes, they can be varied between the value "almost zero" and the almost total filling volume of the tank.

Furthermore, the invention proposes a device for unloading the bulk material, which allows the bulk material to be treated extremely gently during the unloading process.

This problem is solved by the characterizing parts of claims 5-14.

Since the bulk goods mentioned above, for example the nanotubes, are very small - their length is in the micrometer range and their diameter in the nanometer range - it would be extremely difficult to separate the emptied nanotubes from the gas using filters. The filters would quickly become clogged and the bulk material could only be removed from the filter material with great effort. According to the invention, it is therefore basically proposed to carry out the separation of the gas phase from the solid phase using a cyclone. The removal of the loaded bulk material from the tank, its further transport into the cyclone and the return of the unloaded bulk material in turn into the tank is carried out by appropriate pressure drops, which can be generated in different ways.

If, for example, one follows the path of the bulk material flow from the tank to the desorption point in a tank system according to claim 5, one first encounters a valve in conjunction with a pressure sensor for controlling and monitoring the tank system according to the invention. The bulk material flow then passes through the first part of a heat exchanger, where it absorbs heat from the already prepared gas flow. This is followed by the point where the bulk material flow is heated to the desired or necessary desorption temperature. The heating in question can either be designed electrically or as a heat pump or can even be implemented using a hydrogen heater. The prevailing temperature is controlled by one or more temperature sensors. The expansion caused by the heating of the hydrogen can be kept small by setting the pressure accordingly.

After passing the second part of the heat exchanger, which the heat no longer needed

If bulk material is withdrawn, it flows into a cyclone. In this the gas and the bulk material are separated from each other according to the known cyclone principle. While the unloaded bulk material is moving into the designated section of the tank, the gas flow is supplied to the consumer via a pipe provided for this purpose, which may be equipped with a fine screen and a throttle in connection with a pressure sensor. In order to obtain a directed bulk flow, the desorption must work intermittently. To clarify this mode of operation, the individual stages of the cycle are described in detail in connection with the tank system according to FIG. 3.

In a tank system according to claim 5, various sensors are required which, together with a control unit (not shown in detail and not shown), control the heating and the necessary valves or slide valves in accordance with the cycle description.

The tank system described above works without pumps, which is an important prerequisite for the gentle handling of the bulk material. Filters and sieves are also missing when separating the gas from the solid phase.

Furthermore, a hydrogen gas flow partially branched off from the end of the cyclone can generate an overpressure via a turbine in the tank with the loaded bulk material, so that the loaded bulk material is thereby pressed into the cyclone through another pipeline for unloading. The turbine can be designed as an axial turbine; between their rigidly connected paddle wheels there can be heating elements which raise the gas temperature to the required desorption temperature. The heater can advantageously be designed electrically. However, a heat pump or a hydrogen flame would also be adjustable, for example. The blades of the turbine are adapted to the thermal expansion of the gas flow by a factor of approx. 3.7 according to aerodynamic principles. This factor can be reduced by increasing the working pressure. Further details of the inevitable tank system are contained in detail in the illustration description.

The device according to the invention for unloading the bulk goods is characterized in summary by the following advantages: no pumps, no filters or sieves and ~ as required - continuous desorption operation is also possible.

A radial turbine can also be used as the turbine in the context of the tank system according to the invention.

In addition, when the tank system according to the invention is operated in a non-continuous manner, a simple mechanical pump can be used, as is explained, for example, in the description of the figure below with reference to FIG. Finally, it could also make sense to transport the bulk material - especially in stationary systems - by means of vibrating devices known per se; for mobile systems - such as for motor vehicles - this type of bulk material transport may be less suitable, although it cannot be completely ruled out here either.

In order to comply with the legal provisions, the tank system according to the invention should be completely hermetically lockable from its surroundings in order to avoid serious damage in the event of hydrogen leaks.

Figure Description

In the figures, the invention is illustrated by means of FIGS. 1 to 5. Show it:

Fig. 1 shows a tank with a membrane for use in a tank system according to the invention.

Fig. 2 shows a tank with a piston, also usable in a tank system according to the invention.

3 shows a tank system for unloading bulk material loaded with combustible gas from the smallest solids.

4 shows a tank system for the continuous unloading of bulk goods according to FIG. 3.

5 shows a pump system for use as required in tank systems according to FIGS. 3 and 4.

According to the invention, the tank 1 according to the invention is divided longitudinally into two separate sections 5 and 6 by a flexible membrane 3. If the department 5 is filled with bulk material made of, for example, hydrogen-enriched nanotubes, the membrane 3 approaches the lower inner region 9 of the tank 1 with increasing filling until it is completely in contact; in this state the department 5 of the tank 1 can use its almost 100% filling volume. The same applies in reverse for the section 6 of the tank 1. In this case, the membrane 3 lies completely on the upper inner region 16 of the tank 1 as soon as the section 6 is filled. The pipeline 10 of the tank 1 leads in the direction of the arrow 11 to an unloading device 12 or 13 in accordance with FIGS. 3 and 4. The unloaded bulk material is returned from the unloading device 12 or 13 through the pipeline 14 in the direction of the arrow 15 into the tank 1 - 'Out, in its department 6. Because that in the same course, the Ar division 5 takes place through the pipeline 10, moves with the filling of the department 6, the membrane 3 of the tank 1 according to Fig.l so long up until it comes to rest in the 100% filling state of the department 6 on the upper inner surface 16 of the tank 1. In this state, department 5 is completely empty. You can again "refuel" with loaded Bulk goods are filled after the unloaded bulk goods have been removed from the section 6, after which the previously described process of unloading can begin again. The pipeline 17 according to FIG. 1 is used according to arrow direction 18 to generate an internal pressure in the department 5 in order to start and maintain its emptying flow of the bulk material through the pipeline 10. -

2 shows a tank 2 in the shape of a cylinder (lying down), which is equipped with a piston 4 inside, which divides the interior of the tank 2 into the two sections 7 and 8. The piston 4 can be connected to a piston rod 19, which allows the piston 4 to be moved from the outside in accordance with the double arrow direction 20 and, if necessary, also to control its movement by means of suitable auxiliary devices. In full with bulk material, for example The department 4, which is equipped with a combustible gas enriched nanotube, bears the piston 4 against the inner end face 21 of the tank 2 (right in the picture). The department 7 then corresponds to almost the entire filling volume of the tank 2, and so this can be used almost completely to hold enriched bulk material. If now the bulk material from the department 7 is gradually fed through the pipeline 22 in the direction of the arrow 23 to a discharge device, for example the device 13 according to FIG. 4, the piston 4 can move to the extent that the bulk material is removed from the department 7, move to the left towards the inner end face 24 of the tank 2. During this process, the volume of the department 8 increases to the same extent, corresponding to the decrease in the volume of the department 7. The department 8 is thus from the beginning of the unloading process is available for receiving unloaded bulk material, which can be supplied to it through the pipeline 25, which connects the tank 2 to the unloading device 12 or 13, in accordance with the direction of the arrow 26. This is possible until the piston 4 on the end face 24 of the tank 2 comes to rest. In this state, the tank 2 is "empty"; the section 7 can then be filled again with a combustible gas-enriched bulk material after the section 8 has been emptied and the piston 4 has moved to the right until it touches the inner end face 21 of the tank 2 The pipeline 27 is a pressure supply line analogous to the pipeline 17 according to Fig. 1. The direction of the arrow 28 illustrates the direction of the pressure supply.

3 shows a tank 1 which is connected to a discharge device 12 via the pipes 10 and 14. The tank 1 is only missing the pipe 17 compared to the illustration in Fig.l. The pipeline 10 ultimately leads to a cyclone 29 in the direction of the arrow 11. A heater 31 is provided in the region 30 of the pipeline 10; is also in the region 30 of the initial diameter 32 of the pipeline 10 up to the entry into the cyclone 29 to the larger diameter 33. The heating unloads the bulk material. The mixture of discharged bulk material and the combustible gas then flows into the cyclone 29, where it is separated in a manner known per se. The bulk material falls out of the cyclone 29 due to its considerably greater specific weight than the gas and can be fed to the section 6 of the tank 1 via the pipeline 14. At the same time, the combustible gas is supplied via pipeline 34 for use in a fuel cell or in a press brake. Since the gas is still very warm due to the heating of the bulk material after it has been separated from it, it can be economical to provide a heat exchanger which in its part 35 surrounding the pipe 34 absorbs as much heat as possible from the gas flowing out and this via the pipe 36 and its part 37, which surrounds the pipeline 10 even before its region 30, into the pipeline 10 or into the bulk material therein. The valves 38, 39 and 40 serve to regulate the discharge device 12. In the case of the discharge device 12 according to FIG. 3, the pressure feed pipes 18 and 39 according to FIGS. 1 and 2 are not required for tanks 1 and 2, since here the pressure required to start and maintain the discharge process is otherwise generated and maintained. In order to obtain a directed and manageable, controllable flow of bulk material, the desorption of the gas adsorbed on the bulk material must be carried out intermittently. To clarify this, the individual stages of the cycle are described below.

First, the boiler room - that is, the interior of the pipeline 10 in the area 30 - is filled with fresh, loaded bulk material. The valve 40 is closed, as are the valves 39 and 38. The heater 31 is then switched on, as a result of which the pressure in the cyclone rises. The throttle valve 38 is now opened somewhat. In the resulting gas flow, a vortex forms in the cyclone, through which the bulk material discharged by the heating is separated. Now the valve 38 is closed again and the valve 39 is opened. The overpressure still prevailing in the cyclone 29 presses against the membrane 3 in the tank 1 and is thus able to press fresh bulk material into the pipeline 10. After the valve 39 has been closed, the valve 40 is opened until there is sufficient fresh, still loaded bulk material in the boiler room, where the discharge process then begins immediately. The cycle described above can thus begin again.

In the tank system according to the invention, shown schematically in FIG. 3, the individual process steps are mutually coordinated - for a relevant specialist of course - various sensors including a control device required for timely regulation or control of the heating and valves. In addition, it may prove necessary to implement the system, for example. Provide optical sensors and, if necessary, also buffer containers for the bulk material. The tank system according to the invention advantageously works without pumps, which is a very important prerequisite for gentle handling of the sensitive bulk goods. The invention also avoids any filters, sieves or the like for separating the gas from the solid phase. Given the small size of the bulk material particles, for example the nanotubes, it would be difficult, for example, to produce filters with a sufficient service life and the necessary degrees of separation in a cost-effective or economical manner.

If necessary, a pressure required therein can be generated in the tank 2 in the department 7 via the piston rod 19 and the piston 4. -

The discharge device 13 according to FIG. 4 is equipped with a tank 1 according to FIG. 1. Furthermore, it works continuously, thanks to an axial turbine 41, which generates and maintains pressure in the section 5 of the tank 1 via the pipeline 17. This pressure causes the bulk material that has already been discharged in the department 5 to flow out, since the turbine 41, thanks to its heating device 42, brings the required heat into the department 5 in addition to the pressure. From this, the mixture of discharged bulk material and a combustible gas flows through the pipeline 10 into a cyclone 43. There, in turn, the gas is separated from the discharged bulk material in a manner known per se. The gas is supplied through tubing 44 for use in a fuel cell or in an internal combustion engine. The unloaded bulk material is fed from the cyclone 43 via the pipeline 14 to the department 6 of the tank 1. The pipes 10 and 17 are connected via a heat exchanger 45, which transfers excess heat from the pipe 10 into the pipe 17. A valve 46 in the pipeline 44 allows the amount of gas to be removed to be regulated.

5 shows a pump system which, if necessary, can be used in tank systems according to FIGS. 3 and 4 for transporting the bulk material. A tube 47 with a round, square or rectangular cross section is equipped with the two flap valves 48 and 49, which are kept open in their basic position with a weak spring pressure, not shown here. If the piston 50 is moved downward in the direction of 51 in the cylinder 56, which is connected to each ear 47, the valve 48 shoots against its spring pressure and its stop 58 and the contents of the space 52 can escape in the direction 53 through the open vent. If the content is bulk material within the scope of the invention, it can easily be imagined that it can be transported intermittently in this way with the pumping device in the direction 11 according to FIG. 3 if it is with its tube 47 in the pipeline 10 the tank systems according to Figures 3 and 4 is integrated accordingly.

If the piston 50 is moved in the cylinder 56 in the direction of the valve 54, the valve 49 shoots against its spring pressure and its stop 57, while the flap of the valve 48 lifts off its stop 58, so that now further bulk material in the direction of the arrow 55 can flow into space 52.

The closable openings 59 and 60 in the left-hand end wall of the tank 1 according to FIG. 1 serve, as required, for filling or emptying the compartments 5 and 6 of the tank 1. Correspondingly closable openings are also possible for a tank 2 according to FIG. 2 to be provided in order to be able to load and / or unload departments 7 and 8 there as required.

The same is also good for the systems shown in FIGS. 3 and 4, where the openings 59 and 60 are to be provided accordingly in the tank 1 used here. Furthermore, taking into account the regulations regarding the handling of hydrogen, it may be necessary to hermetically seal the tank systems 12 and 13 according to FIGS. 3 and 4 from their surroundings. This can prevent damage from unexpected hydrogen leaks.

The membrane 3 and the piston 4 including its piston rod 19 can also be used for level measurements or for level indicators of the tanks 1 and 2. For this purpose, the membrane 3 would have to be equipped with suitable sensors, for example with optical sensors, while in the tank 2 its current level can be read off directly on the control of the piston rod 19.

Claims

claims

1. Tank system for bulk goods consisting of small to very small solids, which can be loaded with a combustible gas - such as spherical solids with pore or channel structures for storing gases according to DE-PS ... (patent application 100.07.44.4.4) or nanotubes , which are filled, for example, with hydrogen - with a device for unloading the bulk material, characterized in that the filling volume of the tank (1, 2) by a flexible and / or movable element (3, 4) in two hermetically separated compartments ( 5.6 and 7.8), the element (3.4) allowing the divisions (5.6 and 7.8) to be reciprocally reciprocal in volume between the value "almost zero" and the almost total Filling volume of the tank (1, 2) can be varied, and that the tank (1, 2) is connected to a device (12, 13) known per se for unloading the bulk material, which is, however, so ventilated that the unloaded bulk material i n the tank (1, 2) is recyclable.

2. Tank system according to claim 1, characterized in that the tank (1) is sub-divided longitudinally through a flexible membrane (3) into two hermetically separated baffles (5, 6).

3. Tank system according to claim 1, characterized in that the zylindför ige tank (2) by a piston (4) in two hermetically separated from each other (7,8) is sub-divided.

4. Tank system according to claim 3, characterized in that the piston (4) is connected to an outwardly leading piston rod (19) which can be used for control purposes.

5. Tank system according to claims 1 and 2, characterized in that the AbteUung (5) of the tank (1) according to Figure 3 via a pipe (10) is connected to a cyclone (29) that another pipe (14) connects the cyclone (29) to the baffle (6) of the tank (1), that a heater (31) is provided in the funnel-shaped area (30) of the pipeline (10), that the cyclone (29) a pipeline (34 ) for passing on the flammable gases and that the pipes (10, 14, 34) are equipped with valves (40, 39, 38).

6. Tank system according to claim 5, characterized in that the pipes (34) and (10) are connected to one another via a heat exchanger (35, 36, 37).

7. Tank system according to claims 5 and 6, characterized in that in the pipelines (10, 14, 34) in addition to the valves (40, 39, 38) sensors are also provided, which in conjunction with a suitable control device in are able to regulate or control the tank system according to the invention.

8. Tank system according to claims 1 and 2 with a device for the continuous unloading of the bulk material, characterized in that the defrost (5) of the tank (1) according to Figure 4 via pipes (10 and 17) connected to a cyclone (43) is, while this is connected via a pipeline (14) to the defrosting (6) of the tank (1) that an axial turbine (41) with a heater (42) is also provided in the pipeline (17) to build up a pressure in the direction of the arrow (18), and that finally the cyclone (43) is connected to a pipe (44) with a vent (46) for passing on the combustible gases.

9. Tank system according to claim 8, characterized in that the pipes (10) and (17) are connected to one another by a heat exchanger (45).

10. Tank system according to claims 5 to 9, characterized in that fine screens are provided in the pipes (34, 44).

11. Tank system according to one or more of claims 5 to 10, characterized. that a pump system according to FIG. 5 is used to transport the bulk material.

12. Tank system according to one or more of claims 5 to 10, characterized in that known vibrating systems are used for transporting the bulk material.

13. Tank system according to claims 5 to 12, characterized in that any number of valves, slides and sensors are provided for regulating or controlling the bulk material flow in a manner known per se.

4. Tank system according to claims 5 to 13, characterized in that the entire system can be hermetically fired from its surroundings.