CN104838197A - Method of charging sorption store with gas - Google Patents

Abstract

The invention relates to a method of charging a sorption store with a gas, wherein the sorption store comprises a closed container (10) and a feed device which has a passage (21) through the container wall, through which the gas can flow into the container, and the container has at least two parallel, channel-shaped subchambers (30,31,32,33) which are located in its interior and are each at least partly filled with an adsorption medium (40) and whose channel walls are coolable, wherein, in a first step, gas is fed in in such an amount that a pressure in the store of at least 30% of a predetermined final pressure is reached as quickly as possible and in a second step, the amount of gas fed in is subsequently varied in such a way that the course of the pressure in the store approximates the adsorption kinetics of the adsorption medium (40) until the predetermined final pressure in the store is reached after a predetermined period of time.

Description

Method for filling sorption storage with gas

The invention relates to a sorption store for storing gaseous substances comprising a closed vessel at least partially filled with an adsorption medium and a feed device comprising passages through the vessel wall through which gas can flow into the vessel. The invention further provides a method for filling a sorption store with a gas, wherein the sorption store comprises a closed container and a feed device having a passage through the wall of the container through which the gas can flow into the container, and the container has at least two parallel Channel-type sub-chambers in which the sub-chambers are located and which are each at least partially filled with an adsorption medium and whose channel walls are coolable.

For stationary and mobile applications, sorption stores are increasingly being used in addition to pressurized gas tanks for storing gases. Sorption stores generally contain an adsorption medium with a large internal surface area, on which the gas is adsorbed and thus stored. During filling of the sorption store, heat is released due to adsorption and must be removed from the store. Similarly, heat must be provided for the desorption process when gas is withdrawn from storage. Therefore, thermal management is important in the design of sorption stores.

Patent application US 2008/0168776 A1 describes a sorption store for hydrogen comprising an outer vessel thermally insulated from the environment and inside which a plurality of pressure vessels containing the sorption medium are placed. The intermediate space between the pressure vessels is filled with cooling liquid in order to be able to remove the heat developed during the adsorption.

Patent application DE 10 2007 058 673 A1 describes a device for storing gaseous hydrocarbons comprising an insulating container filled with an adsorption medium. A heating element is provided in the vessel and controlled by the control system in such a way that when the gas is withdrawn, the minimum pressure is maintained for a desired long time.

A disadvantage of the known sorption stores is that the filling with gas takes place only slowly. In particular, this disadvantage is particularly acute in mobile applications, for example in motor vehicles.

It is an object of the present invention to provide a device for storing gaseous substances which allows fast filling of gas and improved removal of gas. The device should have a simple structure and require little electrical power during operation. Another object of the invention is to provide a method for filling the reservoir quickly and efficiently.

This object is achieved by the subject-matter of the invention as stated in claim 1 . Further advantageous embodiments of the invention can be found in the dependent claims. Further subjects of the invention are described in claim 9 and the claims dependent thereon.

The process according to the invention is carried out using a sorption store comprising a closed container and a feed device having passages through the container wall through which gas can flow into the container. The container has at least two parallel channel-type subchambers located inside it and each at least partially filled with an adsorption medium, the channel walls of which are coolable. In the first step of the method according to the invention, the gas is fed in such an amount that a pressure of at least 30% of the predetermined final pressure in the reservoir is reached as quickly as possible. In a subsequent second step, the amount of gas fed in can be varied in such a way that the pressure profile in the store approaches the adsorption kinetics of the adsorption medium until a predetermined final pressure in the store is reached after a predetermined time.

For filling, sorption stores, as known from the prior art, are usually connected to a pressure line from which the gas to be stored flows into the store at a constant pressure until a predetermined final pressure in the store is reached. However, it was found that the time required for filling can be significantly reduced when filling is carried out according to the method of the present invention.

In sorption stores, the gas is stored by adsorption on the adsorption medium and in the interstices between and in the individual adsorption medium particles or in regions of the container which are not filled with the adsorption medium. During the first step of the method according to the invention, the void is firstly filled with gas. The pressure in the reservoir follows the pressure of the gas flowing into the container substantially without a time lag. In order to minimize the total time required for the filling operation, this first step should be carried out as quickly as possible, for example by introducing gas at a pressure corresponding to at least 30% of the predetermined final pressure right from the beginning of the filling operation.

During the first step, a part of the gas is adsorbed, whereby the temperature of the adsorbent material and thus the gas flowing through it increases. In the second step, the pressure course in the reservoir approaches the adsorption kinetics of the adsorption medium. Methods for determining adsorption kinetics are known to those skilled in the art, for example by means of pressure jump experiments or adsorption equilibrium (e.g. "Zhao, Li and Lin, Industrial & Engineering Chemistry Research, 48(22), 2009, pp. 10015-10020" middle).

For the purposes of the present invention, the term adsorption kinetics refers to the adsorption process of a gas on an adsorption medium over time under isothermal and isobaric conditions. This process can usually be approximated by an exponential decay function, which initially shows a sharp increase and then becomes progressively smoother as it converges towards the final value. An example of this approximation is the function a·(1-e- ^bt ), where a and b are positive constants. Adsorption kinetics can also be approximated by other functions, such as concave functions, piecewise constant functions, piecewise linear functions or linear functions connecting initial and final values.

The actual flow conditions in the channel-type subchambers of the reservoir depend on the configuration of the channels and the introduction of gas into the channels. In a preferred variant of the sorption store according to the invention, the channel-shaped subchambers are closed at one end. This is the case, for example, if the separating element is connected at one end to the inner wall of the container. In this variant, the gas flowing into the container is advantageously introduced into the open end of the channel-shaped subchamber. In the channel, a portion of the gas becomes adsorbed on the adsorption medium, thus heating the adsorption medium and the surrounding gas. The inner wall of the container and the optionally present at least one separating element or elements are cooled such that a radial temperature gradient is formed between the middle of the channel-shaped subchamber and its periphery. The second step of the feeding strategy of the present invention specifically introduces a continuous gas flow into the vessel. Circulating gas flows are built up internally in channel-shaped subchambers by interacting with radial temperature gradients, and these ensure significantly better heat removal and thus lower maximum temperatures in the adsorption medium.

In a further preferred variant of the energy store according to the invention, the channel-shaped subchambers are open at both ends and are connected to each other in pairs by means of a common space. In this variant, the feed means are preferably configured such that the inflowing gas is fed substantially only into one of the two sub-chambers of each pair of channels. The inventive filling strategy with a pressure course in the reservoir close to the kinetics of adsorption results in a flow rate of gas in the channel-shaped subchambers that is greater than the rate of gas adsorption. This results in the formation of a circulating flow through the channel-type subchambers, ensuring faster removal of the heat developed during adsorption and establishing a lower maximum temperature in the adsorption medium.

Compared to conventional feeding strategies where the pressure is kept constantly high throughout the filling time, the method of the present invention allows the introduction of a larger amount of gas in the same time period during filling or a shorter filling time with the same amount of gas .

The amount of gas fed can be varied, for example, by suitably matching the inlet pressure to an approximation function, for example by suitable valve connections.

In an advantageous embodiment of the method according to the invention, the pressure profile in the accumulator approaches the adsorption kinetics in the form of pressure fluctuations, in particular due to suitable changes in the inlet pressure. The maximum value of the fluctuation preferably corresponds to the final pressure, and the minimum value of the fluctuation preferably approximates the course of the adsorption kinetics. This equates to reduced volatility over time. At the end of the predetermined time, a predetermined final pressure in the reservoir is set. The undulation can be, for example, sinusoidal, saw-tooth-shaped or, as an option, piecewise constant. The shape of the fluctuation as well as its amplitude and duration are preferably matched to the specific adsorption kinetics.

An example of a function of pressure fluctuations that approximates adsorption kinetics is:

p=p0+Δp·f(a)·(sin(2·π·k·t)-1), where:

p ₀ is the initial pressure, p is the difference between the initial pressure and the final pressure, k is the frequency, and f(a) is the damping function. Damping may eg decrease linearly or exponentially. An example is the function f(a)=a/(t+a), where a is a positive number. The frequency k can be estimated by means of the isothermal and isobaric adsorption kinetics t _kin , which is a measure of the minimum filling time. The frequency is preferably chosen such that 2-10 fluctuation periods lie within t _kin . At larger cycle numbers, less heat can be removed per cycle, making the energy consumption required to provide pressure fluctuations uneconomical.

The time required to fill the sorption store is substantially influenced by the material properties of the adsorption medium, in particular its adsorption kinetics. Another influencing factor is the expected maximum temperature during filling, which also depends on the material properties, especially the enthalpy of adsorption. The initial pressure and the type of pressure increase are selected to preferably match the respective adsorption kinetics, adsorption enthalpy and heat transfer to the wall. In the case of rapid thermal removal of the released enthalpy of adsorption, a higher initial pressure is advantageous in order to minimize the total charge time required. Depending on the adsorption kinetics and heat removal, an initial pressure of 30-90% of the predetermined final pressure is advantageous, with ideally high initial pressures being chosen. The magnitude of the initial pressure may be limited by the temperature increase established during adsorption.

It tends to be advantageous to choose a larger pressure difference between the initial pressure and the final pressure, the slower the removal of heat. The rate of pressure increase is preferably at least 1 bar per minute filling time to facilitate the formation of a circulating flow in the channel-shaped subchambers.

In a preferred embodiment of the method according to the invention, the temperature of the gas flow in at least one channel-type subchamber is measured and, if necessary, adapted to the amount of gas fed into the sorption store in such a way that the channel-type subchamber is not exceeded The predetermined maximum temperature in .

Various materials are suitable as adsorption media. The adsorption medium preferably comprises zeolites, activated carbon or metal-organic frameworks.

The porosity of the adsorption medium is preferably at least 0.2. Porosity is defined as the ratio of the void volume to the total volume of any subvolume in the container. At lower porosities, the pressure drop across the adsorption medium increases, which has an adverse effect on the filling time.

In a preferred embodiment of the invention, the adsorption medium is present as a bed of granules and the ratio of the permeability of the granules to the smallest granule diameter is at least 10 ⁻¹⁴ m ² /m. The rate at which gas permeates the pellet during packing depends on how quickly the pressure inside the pellet approaches the pressure outside the pellet. The time required for this pressure equalization and thus also the loading time of the pellets increases with decreasing permeability and with increasing diameter of the pellets. This can have a limiting effect on the overall method of filling and draining.

The time required for filling can be further reduced when the gas is cooled prior to introduction.

At least one separating element or a plurality of separating elements, in particular all separating elements present preferably have a double wall, so that the heat transfer medium can flow through them. It is also preferred that all channel walls of the channel-type subchambers are double-walled to allow the heat transfer medium to flow through them. Depending on the at least one separating element or the arrangement of the separating elements, a part of the inner wall of the container forms a channel wall of a channel-shaped sub-chamber or of a plurality of channel-shaped sub-chambers. In this case, too, the container wall is preferably double-walled. In a particularly preferred embodiment, the entire container wall including the end faces is configured to allow the heat transfer medium to flow through it, in particular as a double wall.

Depending on the temperature range suitable for cooling or heating the gas in the sorption store, various heat transfer media such as water, glycols, alcohols or mixtures thereof are possible. Suitable heat transfer media are known to those skilled in the art.

It has been found advantageous that the channel walls in each channel-type subchamber have a spacing of 2-8 cm. Here, the term pitch refers to the shortest distance between two points on opposing walls seen in a cross-section perpendicular to the axis of the channel. In the case of a channel with a circular cross-section, for example the pitch corresponds to the diameter, in the case of a circular cross-section it corresponds to the width of the ring, in the case of a rectangular cross-section it corresponds to the distance between parallel sides. short distance. Especially in the case of cooling or heating of all channel walls, this range was found to be a good compromise between heat transfer and filling volume of the adsorption medium. At larger spacings, the heat transfer between the adsorption medium and the wall deteriorates; at smaller spacings, the filling volume of the adsorption medium decreases for a given external vessel size. In addition, the weight of the sorption store and its production costs increase, which is disadvantageous, especially in the case of mobile applications.

In a preferred embodiment, the distance between the channel walls in the channel-shaped subchambers differs by no more than 40%, particularly preferably by no more than 20%. This configuration facilitates the uniform removal of heat during filling or the introduction of heat during emptying of the container.

The container of the sorption store is preferably cylindrical and the at least one separating element is arranged substantially coaxially with the axis of the cylinder. Embodiments in which the longitudinal axis of at least one separating element is inclined by a few degrees up to a maximum of 10 degrees relative to the axis of the cylinder are considered to be "substantially" coaxial. This configuration ensures that the channel cross section varies only slightly along the axis of the cylinder so that a uniform flow over the length of the channel can be established.

Depending on the space available for installation and the maximum permissible pressure in the container, various cross-sectional areas of the cylindrical container are possible, eg circular, oval or rectangular. Irregularly shaped cross-sectional areas are also taken into account when the container is installed in the hollow space of a vehicle body, for example. For high pressures above about 100 bar, circular and elliptical cross sections are particularly suitable.

The invention further provides a sorption store for storing a gaseous substance comprising a closed container and a feed device comprising a passage through the container wall through which the gas can flow into the container. The container has at least one separating element located inside it and configured such that the interior of the container is divided into at least two parallel channel-shaped subchambers, each of which is at least partially filled with an adsorption medium and whose channel walls are chilled. According to the invention, viewed in cross-section, the contours of the container inner wall and of the at least one separating element and optionally a plurality of separating elements are substantially conformal.

Conformal in this context means that the contours have the same shape, for example both are circular, both are elliptical or both are rectangular. The expression "substantially conformal" means that small deviations from the basic shape are still included in "the same shape". Examples are rounded corners in the case of a rectangular basic shape or deviations within production tolerances.

This configuration allows an optimal use of the inner space of the container for a very large amount of adsorption medium combined with efficient thermal management.

The abovementioned preferred structural features such as double-walled separation elements, channel wall spacing and/or coaxial arrangement of the separation elements in the cylindrical container also represent preferred embodiments of the sorption store according to the invention.

The choice of the wall thickness of the container and of the separating element depends on the maximum pressure expected in the container, the dimensions of the container, especially its diameter, and the properties of the materials used. In the case of an alloy steel vessel with an outer diameter of 10 cm and a maximum pressure of 100 bar, the minimum wall thickness is estimated to be, for example, 2 mm (according to DIN 17458). The internal spacing of the double walls is chosen such that a sufficiently large volume flow of the heat transfer medium can flow through them. It is preferably 2-10 mm, particularly preferably 3-6 mm.

The at least one separating element is particularly preferably configured as a tube such that the inner space of the tube forms a first channel-shaped subchamber and the space between the outer wall of the tube and the inner wall of the container or optionally between the outer wall of the tube and another separating element forms a second channel-type subchamber. Annular channel type subchamber. Viewed in cross-section, the contours of the tubular separation elements are conformal to the contours of the inner walls of the container; they are for example both circular or both elliptical. In another development of this embodiment of the invention, there are a plurality of separating elements, all configured as tubes with various diameters and arranged coaxially. Viewed in cross-section, their profile also conforms to the profile of the inner wall of the container.

The feed means comprise at least one passage through the container wall through which gas can flow into the container. In a particular embodiment, the feed means comprise a tubular feed line connected at one end to at least one channel and which diverges into ends leading to individual channel-type subchambers. In an alternative embodiment, the feed means comprises a plurality of passages through the vessel wall, all connected at one end to a tubular feed line, the other end of which leads to a channel-type subchamber.

In a further advantageous embodiment, the feed device comprises components for distributing the gas flowing in through at least one channel in a defined manner into all subchambers, for example deflection elements or distribution devices.

The inflow quantities of gases are particularly preferably distributed in the channel-shaped subchambers in such a way that the ratio of the individual gas quantities to one another corresponds to the ratio of the cross-sectional areas of the subchambers.

The feeding device may also contain devices for influencing the gas flow, such as throttle valves or regulating valves. These means can be provided inside or outside the container. Multiple passages may also be provided in the container wall, for example in order to introduce gas into the channel-type subchamber at multiple places, or to provide different passages for filling and withdrawing gas. The gas is preferably withdrawn using one or more of the same passages used to fill the container.

Compared to the prior art, the sorption store according to the invention enables heat to be transported out of or into the sorption medium more quickly. This significantly reduces the time required to fill the reservoir with a given amount of gas. Alternatively, the reservoir can be filled with a larger amount of gas in a given time. The invention allows for a rapid and continuous supply of gas as it is withdrawn from the reservoir. To this end, the channel walls are heated, for example in the case of a double-wall configuration, through which a heat transfer medium whose temperature is greater than the temperature of the gas in the channel-shaped subchambers passes. The sorption store according to the invention is structurally simple and, due to its compact design, is particularly suitable for mobile applications, for example in motor vehicles. The embodiment with double channel walls has another advantage: only the heat transfer medium or its temperature has to be changed appropriately to change from cooling or heating. Therefore, this embodiment is suitable for mobile use during fill and drive modes.

The invention is explained in greater detail below with the aid of the drawings; the drawings are to be interpreted as a principled description. They do not limit the invention, eg with respect to specific dimensions or constructional variables of the components. For clarity, they are generally not to scale, especially with regard to length and width ratios. The graph shows:

Figure 1: Embodiment of the inventive sorption store with a flow equalizer for the inflowing gas

Figure 2: Embodiment of a sorption store according to the invention with double channel walls, elliptical cross-sectional area of the container and multiple passages

Figure 3: Embodiment of a sorption store according to the invention with a rectangular cross-section of the container

Figure 4: Example of a flow chart for determining the initial pressure for filling a sorption store according to the invention

Figure 5: Comparison of the packing strategy of the present invention and the conventional packing strategy

List of reference numbers used

10…container

11…container wall

15...separation element

16...separation element

17...separation element

21...access

22…cover plate

30…first sub-chamber

31…Second sub-chamber

32...the third sub-chamber

33…Fourth sub-chamber

40…adsorption medium

5x... Process steps for determination of initial pressure

1-3 show schematic sections through a sorption store according to the invention. The illustrative sorption store has a substantially cylindrical container 10 . The upper figures in each case describe a longitudinal section through the axis of the cylinder, these respective lower figures show the corresponding cross section perpendicular to the axis of the cylinder.

FIG. 1 shows a first preferred embodiment of the sorption store according to the invention. The container 10 has a circular cross section and has a passage 21 through the container wall on its end face. Located inside the container 10 is a separating element 15 configured as a tube with a circular cross section and arranged coaxially with the axis of the cylinder. The inner space of the tube forms a first channel-type subchamber 30 . The space between the outer wall of the tube and the inner wall of the container forms a second annular channel-type sub-chamber 31 . The separation element 15 has a distance from the end face of the inlet end; on the opposite end, it extends to the end face of the container. In the example shown, both subchambers 30 , 31 are completely filled with adsorption medium 40 . At the end facing the passage 21, the subchambers 30, 31 are joined by a cover plate 22 extending over the entire cross-section of the container. In the example shown, 5 openings are present on the cover plate 22 through which the airflow can flow into the subchambers. The cover plate acts as a flow equalizer, which ensures an even flow of gas into the subchambers 30 , 31 . The openings shown are examples; they also have another configuration. For example, an annular or discontinuous annular opening may be provided in the outer region connecting the passage 21 with the second subchamber 31 .

Broken arrows symbolize the gas flow inside the container. The inflowing gas first enters the space between the channel 21 and the cover plate 22 which is not filled with the adsorption medium and becomes evenly distributed there. The gas flows through the openings in the cover into the two subchambers 30 , 31 where it is adsorbed on the adsorption medium. The adsorption medium and the surrounding gas are heated due to adsorption. The inner wall of the container 10 and the separating element 15 are cooled such that a radial temperature gradient is established between the middle of the channel-shaped subchamber and its periphery. The second step of the feeding strategy of the present invention specifically produces a continuous gas flow into the vessel. This interacts with the radial temperature gradient to generate a circulating air flow, which ensures a significantly better heat removal and thus establishes a lower maximum temperature in the adsorption medium inside the channel-shaped subchambers 30 , 31 . Thus, the vessel can be loaded with the same amount of gas in a shorter time than with conventional feeding strategies where the pressure remains constant high throughout the filling time.

FIG. 2 shows another preferred embodiment of the sorption store according to the invention. The container 10 has an elliptical cross-section, and a tubular separating element 15 , also having an elliptical cross-section, is arranged inside the container coaxially with the axis of the cylinder. As in the previous example, the inner space of the tubular separating element 15 forms a first channel-type subchamber 30 and the space between the outer wall of the tube and the inner wall of the container forms a second annular channel-type subchamber 31 . The channel walls of the channel-shaped subchambers 30 and 31 formed by the container wall 11 and the separating element 15 have double walls so that a heat transfer medium can flow through the walls. Corresponding feed and discharge connections for the heat transfer medium are provided but not shown in the figures.

In this example, the entire inner volume of the container is filled with the adsorption medium 40 . The feed means comprise 5 passages 21 through the container wall through which the gas can flow into the interior of the container. Passage 21 is located on one end face of container 10 , is configured as a tube and is arranged uniformly around the circumference in the region of annular outer subchamber 31 and also centrally in the middle of the end face as inlet to inner subchamber 30 . In this embodiment, the separating element 15 extends at both ends to the respective end faces of the container.

Broken arrows symbolize the gas flow inside the container. In this example, the inflowing gas is distributed directly on the adsorption medium through five channels 21 . The formation of the temperature gradient and the gas flow of the internal circulation in the subchambers 30 , 31 proceeds similarly to the example described above with respect to FIG. 1 .

FIG. 3 shows another preferred embodiment of the sorption store according to the invention. The container has a cylindrical shape and a substantially rectangular cross-section. The corners are rounded and the container wall 11 is double walled to allow the heat transfer medium to flow through it. The interior of the container is divided by three separating elements 15, 16, 17 into four channel-type subchambers 30-33. The separating elements are evenly distributed in the longitudinal direction of the container, so that the subchambers likewise have a rectangular cross section with essentially the same inner area. In the example shown, the cross-section of the subchamber is square with rounded corners. The separating elements are configured as double-walled plates and run longitudinally coaxially with the axis of the cylinder and transversely parallel to the container inner wall of the container opposite or parallel to the adjacent separating element. Viewed in cross-section, the inner wall of the container and the profile of the separating element are thus conformal. Axially as well as transversely, the separating elements each extend to the inner wall of the container and are connected thereto, so that four completely separate subchambers are obtained in the container.

For each subchamber 30 , 31 , 32 , 33 the channel 21 through which gas can flow into the container is provided via the end face of the container wall. Passages 21 are tubular and extend into the respective subchambers. All channel-type subchambers are filled with adsorption medium.

In this figure, the broken arrows also symbolize the gas flow in the container. In a similar manner to the embodiment of FIG. 2 , the inflowing gas is distributed through passage 21 directly onto the adsorption medium. Due to the cooling of the channel walls, a temperature gradient is established from the middle of the channel to the channel walls when viewed in cross section. As described with respect to Figure 1, the feed strategy of the present invention produces a continuous gas flow into the vessel, combined with a temperature gradient to generate a gas flow internally circulated in the channel-type subchambers 30, 31, 32, 33, leading to the above-mentioned advantages.

To improve the heat transfer, other components for transferring heat can also be provided, such as a central tube running in each case along the axis of the cylinder in each subchamber 30 , 31 , 32 , 33 . Of course, such measures may also be advantageous in embodiments other than those shown in FIG. 3 .

FIG. 4 shows, as an example, a flow diagram for determining the initial pressure p ₀ of a sorption store filled according to the invention. At start 51 , first a starting value for the initial pressure p ₀ is selected in an initialization phase 52 , for example 50% of the final pressure to be achieved. Furthermore, an upper limit for the permissible temperature T _max in the reservoir and the required final filling time _te are set, for example 5 minutes.

Step 53 includes the actual performance of the experiment. An empty sorption store is filled with a gas whose pressure at the store inlet is constant p ₀ from the starting point in time to a point in time t ₀ set at eg 1 minute. Over the period from t ₀ to the final time t _e , the pressure at the inlet to the accumulator is increased according to a predetermined function approximating the adsorption kinetics of the adsorption medium used.

The maximum temperature reached during load operation in step 54 is compared with a predetermined upper limit T _max . If the upper limit is exceeded, the initial pressure p ₀ is reduced in step 55 , for example by a predetermined value, by a predetermined percentage or nested as an interval. However, the pressure should not fall below a minimum pressure which amounts to 30% of the final pressure. The experiment was then repeated using a reduced initial pressure (step 53).

However, if the predetermined upper temperature limit T _max has not been reached, then in a next step 56 a check is made as to whether the total gas load of the store is satisfactory at the final time t _e . The criterion may be, for example, a total load of at least 95% of the maximum absorbent capacity. If the load is still not satisfactory, another iteration of increasing the initial pressure p ₀ is performed in step 57 . The pressure can be increased by, for example, a predetermined value, a predetermined percentage, or nested as intervals. The experiment is then repeated with an increased initial pressure (step 53).

If the temperature criteria are followed (step 54) and the total load is also satisfactory, the experimental procedure ends (step 58). In this way, the optimum value for the initial pressure can be determined in several targeted experiments. The experiments were performed easily and only once required the design of the actual sorption store. In a similar manner, or in combination with the sequence described above, the feed strategy can be set or optimized from the initial pressure to the final pressure. Example

The results of simulation calculations performed using the program OpenFOAM (from ENGYS) are shown below. Calculations are based on the following assumptions:

- The aggregate bed can be considered as a porous medium and a homogeneous phase separated from the gas phase. It is therefore not necessary to quantitatively resolve each individual agglomerate.

- All granules have the same properties in terms of particle size, permeability, density, heat capacity, conductivity, adsorption enthalpy and adsorption kinetics.

- The flow effect on the heat transfer of the bed can be described by known relationships.

The calculations are based on a cylindrical container with a circular cross section, an internal length extension of 100 cm and an internal diameter of 17 cm. Inside the container, a tube with a circular cross-section is mounted as a separating element concentrically with the axis of the cylinder. It has a double wall and an internal diameter of 5 cm. Its wall thickness is 1 cm in total and the gap width between the walls of the double wall is 3 mm. This configuration corresponds to the example according to FIG. 2 , but with a circular cross section. The interior of the container is thus divided into two parallel channel-type subchambers that are completely separated from each other. The spacing of the channel walls was 5 cm in both subchambers. The container walls were also double-walled with a total wall thickness of 1 cm and the gap width between the walls of the double-wall was 3 mm. The tubing connected to passage 21 protrudes 8 cm into the container.

The container had a fill volume of 19 L and was filled with pellets of metal-organic framework type 177 as adsorption medium. Type 177 MOFs comprise zinc clusters linked by means of 1,3,5-tris(4-carboxyphenyl)benzene as organic linker molecules. The specific surface area (langmuir) of the MOF is 4000-5000 m ² /g. Further information on this type can be found in US 7,652,132 B2. The pellets had a cylindrical shape with a length of 3 mm and a diameter of 3 mm. Their permeability is 3·10 ^-16 m ² . The ratio of permeability to smallest pellet diameter is thus 10 ⁻¹³ m ² /m. The porosity of the bed is 0.47.

Check The container was filled with pure methane fed in at a temperature of 27°C. The intended final pressure is 90 bar absolute. The heat transfer medium flows through the vessel wall and the individual separating elements in such a way that a constant wall temperature of 27° C. is established. Under these conditions, the container can be filled with a maximum of 2 kg of methane.

The lower panel in Figure 5 shows the results for both scenarios. In the comparative variant (solid curve), the gas is fed into the aforementioned vessel at a constant pressure of 90 bar from the start. A final pressure of 90 bar is reached in the vessel within the first minute. After about 32 minutes, 0.9 kg of methane was adsorbed (time t ₁ in FIG. 5 ). At this point in time, the void in the pellet bed was filled with another kg of methane, so that the vessel was loaded with methane to the extent of 95%.

In the variant according to the invention (broken curve), the same container configuration as in the comparative variant was used as basis. However, gas was only fed at 80 bar for an initial period of 1 minute until the internal pressure in the vessel rose to 80 bar. The inlet pressure of the methane fed was then increased to a final pressure of 90 bar over a period of 30 minutes according to a function matched to the adsorption kinetics:

p(t)=p ₀ +Δp·(1−e ^−kt ), where p ₀ =80 bar, Δp=10 bar and k=0.0025 s ⁻¹ .

The pressure course over time is shown in the upper panel in FIG. 8 . In the case of the canister considered, the simulated MOF type showed rapid thermal removal relative to the adsorption kinetics, so a value of about 90% of the final pressure was chosen as the initial pressure. The major part of the methane to be adsorbed is adsorbed within the first minute. This leads to a sharp increase in the temperature of the adsorption medium.

The simulation results demonstrate that the flow circulating inside the channel-type subchamber is induced by means of this mode of operation of the invention. Due to this flow, the heat developed by the adsorption medium due to adsorption is removed more quickly on the cooling walls. This in turn causes adsorption to occur more quickly and the vessel to be 95% charged with methane after only about 26 minutes (time _t2 in the lower panel of Figure 5).

Claims (13)

1. A method for filling a sorption store with a gas, wherein the sorption store comprises a closed container (10) and a feed device having a passage (21) through the wall of the container through which the gas can flow into the container, and the container has at least Two parallel channel-type sub-chambers (30, 31, 32, 33) located inside and each at least partially filled with an adsorption medium (40) and whose channel walls are coolable, wherein at In one step, gas is fed in such an amount that a pressure of at least 30% of the predetermined final pressure in the reservoir is reached as quickly as possible, and in a second step, the amount of gas fed is then varied in such a way that the storage The pressure profile in the reservoir approximates the adsorption kinetics of the adsorption medium (40) until a predetermined final pressure in the reservoir is reached after a predetermined time. 2. The method according to claim 1, wherein the channel walls of the channel-type subchambers (30, 31, 32, 33) are configured as double walls, and the heat transfer medium flows through them. 3. The method according to claim 1 or 2, wherein the distance between the channel walls in each channel-shaped subchamber (30, 31, 32, 33) is 2-8 cm. 4. The method according to any one of claims 1-3, wherein the spacing of the channel walls in the channel-shaped subchambers (30, 31, 32, 33) differs by no more than 40%, in particular by no more than 20%. 5. The method according to any one of claims 1-4, wherein the adsorption medium (40) has a porosity of at least 0.2. 6. The method according to any one of claims 1-5, wherein the adsorption medium (40) is present as a bed of pellets and the ratio of the permeability of the pellets to the smallest pellet diameter is at least ^{10-14 m2} /m. 7. The method according to any one of claims 1-6, wherein the adsorption medium (40) comprises zeolites, activated carbon or metal organic frameworks. 8. The method according to any one of claims 1-7, wherein the temperature of the gas flow in at least one channel-type subchamber (30, 31, 32, 33) is measured and in a certain way compared with the temperature of the gas supplied to the sorption store when required The amount of gas is matched so that a predetermined maximum temperature in the channel-shaped subchamber is not exceeded. 9. A sorption store for storing gaseous substances comprising a closed container (10) and a feed device comprising passages (21) through the wall of the container through which the gas can flow into the container, wherein the container has at least one separating An element (15, 16, 17) inside which said separating element is arranged so that the interior of the container is divided into at least two parallel channel-type subchambers (30, 31, 32, 33), each of which is at least partially Be filled with adsorption medium (40), and its channel wall is coolable, and wherein with cross-sectional view, the inner wall of container and at least one separation element (15,16,17) and the profile of optional plurality of separation elements are substantially conformal. 10. The sorption store according to claim 9, wherein the channel walls of the channel-type sub-chambers (30, 31, 32, 33) are configured as double walls to allow the heat transfer medium to flow through them. 11. The sorption store according to claim 9 or 10, wherein the distance between the channel walls in each channel-shaped subchamber (30, 31 , 32, 33) is 2-8 cm. 12. A sorption store according to any one of claims 9-11, wherein the container (10) is cylindrical and at least one separating element (15) is arranged substantially coaxially with the axis of the cylinder. 13. The sorption store according to claim 12, wherein at least one separating element (15) is configured as a tube such that the inside of the tube forms a first channel-type subchamber (30) and between the outer wall of the tube and the inner wall of the container or any The space between the outer wall of the selection tube and the other separating element (16, 17) forms a second annular channel-type subchamber (31).