DE102007058673A1 - Method for storing gaseous hydrocarbons - Google Patents

Abstract

The invention relates to a method for storing gaseous hydrocarbons in a sorption store (5), wherein the temperature of the stored hydrocarbon is less than the room temperature and greater than the evaporation temperature of the carbon when the sorption store (5) is filled. Furthermore, the invention relates to a compound for storing gaseous hydrocarbons, comprising a Sorptionsspeicher (5), which is isolated from the environment. The sorption storage (5) contains zeolite, activated carbon or organometallic framework compounds.

Description

State of the art

The The invention relates to a method for storing gaseous Hydrocarbons in a sorption storage. Furthermore the invention provides a device for storing gaseous Hydrocarbon substances according to the preamble of claim 10.

to Storage of gaseous hydrocarbons are used today generally pressurized gas tanks. these can both in stationary applications, eg. B. for heating of buildings, or in mobile applications, such. B. in gas-powered Motor vehicles, are used. Regarding mobile applications of pressurized gas tanks, these are usually for a system pressure designed from 200 bar and are in one with gaseous Fuel-powered motor vehicle installed. The storage usually takes place at ambient temperature. disadvantage of compressed gas tanks for storage of gaseous hydrocarbons is that particular when used in motor vehicles special Safety requirements are made. Furthermore, in particular in terms of mobile applications of pressurized gas tanks the circumstance disadvantage that due to safety regulations for Gas tanks for motor vehicles usually serve as gas tanks cylindrical pressure vessel are formed, wherein the permissible filling quantity only at 80% of the available volume lies. The remainder of the existing volume of the compressed gas storage serves as an expansion space for the gas.

In addition to pressure accumulators, there is currently a tendency to use sorption accumulators. Sorption stores generally contain a highly porous material, e.g. B. a MOF (Metal Organic Framework) with high internal surface. The gas is absorbed by the highly porous material and stored thereby. Sorption stores are currently in particular, z. B. off US Pat. No. 6,748,748 , known for hydrogen.

Disclosure of the invention

Advantages of the invention

At the Inventive method for storing gaseous hydrocarbons in a sorption storage is the temperature of the stored hydrocarbon when the sorption reservoir is full less than room temperature and larger than that Evaporation temperature of the hydrocarbon. Preferably lies the temperature below the boiling temperature of nitrogen, d. H. the temperature is less than -196 ° C.

One Sorption storage generally contains a highly porous Material, eg. As a MOF (Metal Organic Framework). Other suitable highly porous materials for storing the gaseous Hydrocarbons are z. As zeolites and activated carbon.

Thereby, that the temperature of the stored hydrocarbon when filled Sorption memory is reduced, the storage capacity can be reduced of the sorbent material increase. It can be more hydrocarbon be absorbed by the Sorptionsspeicher. By making the temperature bigger is held as the vaporization temperature of the hydrocarbon, This avoids the hydrocarbon in the sorption storage condensed. The hydrocarbon is still present in gaseous form.

In A preferred process variant is the temperature of the hydrocarbon less or equal when filling the sorption reservoir the temperature of the stored hydrocarbon when filled Sorption. As a result, the energy requirement in the sorption storage be reduced for cooling the hydrocarbon, since these are no longer cooled down to storage temperature got to. In addition, already when filling the Sorptionsspeichers the maximum storage capacity of the sorption material achieved. Another advantage of filling the Sorptionsspeichers with already cooled hydrocarbon is that heavier boiling constituents of the gaseous hydrocarbon Condens out before filling the sorption reservoir and so did not get into the Sorptionsspeicher. In this way it is avoided that the sorption storage by heavy boiling Components of gaseous hydrocarbons contaminated and in this way the storage capacity with the Time decreases.

Gaseous hydrocarbons for the purposes of the present invention are, in particular, C ₁ -C ₄ -alkanes, C ₂ -C ₄ -alkenes and C ₂ -C ₃ -alkynes. Particularly preferred hydrocarbons are natural gas, methane, ethane, propane and butane. And more preferably, the gaseous hydrocarbon is selected from natural gas or methane.

Around to be able to keep the temperature in the sorption storage is it is preferred if the sorption storage for temperature control of the gaseous Hydrocarbon is cooled. The used cooling medium depends on the temperature to which the Sorptionsspeicher to be cooled. Especially as a coolant is suitable for. As liquid nitrogen.

Furthermore, it is preferred if the sorpti memory is enclosed by an insulation. The insulation prevents the sorption storage from being warmed up by the environment. In particular, in previously cooled hydrocarbons, it is possible in this way, to use for cooling only little energy. With a particularly good insulation, it may even be possible to completely dispense with the cooling.

In A preferred variant of the method is for emptying the Sorptionsspeichers the temperature in the sorption storage with decreasing content of gas until reaching a maximum allowable temperature such increases that a predetermined minimum pressure in the sorption not fallen below.

By the increase in temperature decreases the storage capacity of sorption storage. In this way, more and more gas is released. The maximum permissible temperature until reaching the Heated sorption store is chosen so that only a small proportion of gas in Sorptionsspeicher remains.

Of the given minimum pressure depends on the consumer, which is to be supplied with the gas from the Sorptionsspeicher. So z. B. when using the Sorptionsspeicher in motor vehicles a minimum pressure required to work at given valve cross sections still be able to provide the desired gas mass. This is necessary to get the desired burning power to reach. Below the minimum pressure must be reduced performance be accepted or it is possible that the gas metering valves do not open anymore. Gas consumers in the vehicle are z. B. the internal combustion engine in gas-powered internal combustion engines or a fuel cell.

By Increase of temperature at emptying of sorption storage the usable tank capacity is increased considerably, whereby a reduced space of the tank with the Sorptionsspeicher or a greater range when used in the vehicle can be realized. In addition, the maximum power, that is a constant gas pressure ready until the tank is essentially empty is.

In In a first embodiment, the temperature becomes stepwise elevated. Here, each gas at a constant temperature until reaching a predetermined setpoint for the Pressure is taken and upon reaching the setpoint, the temperature increased until a predetermined upper pressure limit is reached becomes. Due to the decreasing sorption capacity of the sorption reservoir with increasing temperature decreases due to the temperature increase the pressure in the tank too. Therefore, when raising the temperature Make sure that the maximum permitted tank pressure is not exceeded. Too high pressure could otherwise lead to damage the tank and possibly even lead to a bursting of the tank. Especially at higher temperatures, it is necessary to carry out only slight temperature increases, because even with small temperature increases a strong Increase in pressure occurs. At low temperatures, like them at the beginning of the removal process and with strongly cooled Sorptionsspeicher present, also lead larger Temperature increases only to a small pressure increase.

Around to avoid that the pressure during heating up the permissible Maximum pressure of the tank, it is therefore preferable that the predetermined upper pressure limit the maximum allowable storage pressure equivalent.

There an undershooting of the predetermined minimum pressure z. B. to a Performance decrease of the gas-powered internal combustion engine or fuel cell leads, it is preferred that the predetermined setpoint for the pressure assumes a value between the given Minimum pressure and the maximum permissible storage pressure is. This ensures that the pressure at the gas extraction does not fall below the specified minimum pressure. The upper Boundary of the range is chosen so that the Sorptionsspeicher the largest possible amount of gas in the achieved Temperature can be taken.

By the incremental increase in temperature is a comparative one simple 2-step control possible.

The Heating the Sorptionsspeichers z. B. by a heater, which is arranged in the tank. The heating can be z. B. by heat exchange done with a heating medium. However, it is also possible that the heating z. B. performed with electrical elements Heizele becomes. Alternatively, however, is also a heating by a targeted Interruption of the thermal insulation of the tank possible. The targeted interruption of thermal insulation leaves z. B. by thermal bridges, preferably are switchable, achieve.

at the heating of the tank with a heating medium is usually a liquid heating medium used. This is going through cooled the heating of the tank. That way cooled heating medium can be z. B. for temperature control use of the interior of a motor vehicle, in which the inventive Method for controlling the removal of the gas from the Sorptionsspeicher used becomes.

In an alternative embodiment is from reaching a given pressure, the temperature in Sorptionsspeicher at removal of gas increased so that the pressure is substantially constant remains until a predetermined maximum allowable temperature is reached. To get as complete as possible To achieve emptying of the tank, it is preferable if the given Pressure from which the temperature in the sorption tank increases is substantially equal to the predetermined minimum pressure. Essentially equal to the predetermined minimum pressure also means in this case, that the given pressure is in the range between the Minimum pressure and a maximum pressure of 10% greater than is the predetermined minimum pressure is.

in the Difference to the gradual increase in temperature is in temperature control, where the pressure is substantially constant remains, a larger regulatory effort required.

the Sorption storage can as long as gaseous hydrocarbon be removed until the maximum allowable temperature and the predetermined minimum pressure is reached. The maximum allowed Temperature is determined so that a possible complete emptying of Sorptionsspeichers achieved To maximize the capacity of the sorption reservoir to fully exploit. The maximum allowed Temperature can also be above the bypass temperature.

The The invention further relates to a device for storing gaseous Hydrocarbons comprising a sorption reservoir facing the environment is isolated, wherein the sorption storage zeolites, Activated carbon or organometallic framework compounds (metal Organic Framework, MOF).

By The isolation of sorption storage is achieved that little Heat from the environment is absorbed and so is the hydrocarbon stored in the sorption reservoir is slow heated by heat from the environment. This allows the energy required for cooling of the gaseous hydrocarbon.

zeolites, Activated carbon or MOFs are particularly suitable for sorption of gaseous Hydrocarbons. When the gaseous hydrocarbon Natural gas or methane is, in particular MOFs as storage media suitable.

Around the gaseous hydrocarbons stored in the sorption reservoir it is preferred to cool when the sorption a cooling device comprises. Each is suitable here Any cooling device known to those skilled in the art. Furthermore is it is also possible that z. B. in Sorptionsspeicher channels are formed, which flows through a cooling medium become. The channels can z. B. in the form of a Pipe be formed, which contained in Sorptionsspeicher is. As a coolant is as already above described, for. As liquid nitrogen.

The Device according to the invention preferably detects continue a control system that increases the temperature be controlled in the Sorptionsspeicher at removal of gas so can that until reaching a maximum allowable temperature a predetermined minimum pressure is not exceeded. By the Control device, it is possible, the temperature at gas extraction to increase to the fullest possible To remove the gas from the Sorptionsspeicher to achieve. The regulation can be done either, as described above, either way, that the temperature is increased gradually or alternatively the temperature is increased so that the pressure during the temperature increase remains substantially constant.

Around the sorption storage with the gaseous contained therein To heat hydrocarbon it is preferred if the Device further comprises a heating element, with which the Sorptionsspeicher can be heated. The heating element is z. B. a heater, which is arranged in the tank. Here, the heating z. B. by Heat exchange with a heating medium. Alternatively it is but also possible that z. B. electrical heating elements be used.

Next the use of a heating element, it is also possible that the cooling device is also used for heating. In In this case, the cooling medium previously used to cool the Sorptionsspeicher and the gaseous contained therein Hydrocarbon was used, heated, causing also the temperature in the sorption storage is increased.

In order to fill and empty the sorption reservoir, it is possible, on the one hand, for a connection to be provided with a valve via which gas is first introduced into the sorption reservoir. As soon as the sorption reservoir is completely filled, the gas can also be withdrawn via the same connection. In an alternative embodiment, however, two separate ports are provided. One port for filling the sorption reservoir and a second port for gas removal from the sorption reservoir. The two connections are particularly advantageous when the sorption is used in a vehicle. In this way, the Sorptionsspeicher can befül via an inlet nozzle with gas len. The inlet connection ends for this purpose preferably on the body outside of the vehicle to allow easy filling of the tank. The gas can be removed again via a second connection. For this purpose, the second port z. B. with the internal combustion engine in a gas-powered internal combustion engine or with the fuel cell, when the vehicle is operated with a fuel cell connected.

Brief description of the drawings

embodiments The invention is illustrated in the drawings and in the following Description explained in more detail.

It demonstrate:

1 a device according to the invention for storing a gaseous hydrocarbon,

2 the method for withdrawing methane in a first embodiment in a storage capacity pressure diagram,

3 the method according to the invention for the removal of methane in a second embodiment in a storage capacity pressure diagram.

embodiments the invention

In 1 schematically a device according to the invention for storing a gaseous hydrocarbon is shown.

A device 1 for storing a gaseous hydrocarbon comprises a tank 3 , the sorption storage 5 contains. The sorption storage 5 is preferably a porous organometallic framework compound (MOF). Organometallic framework compounds are for. B. described in US 5,648,508 . EP-A 0 790 253 . M. O-Keeffe et al., J. Sol. State Chem., 152 (2000), pages 3 to 20 . Li, H., et al., Nature 402 (1999), 276 . M. Eddaoudi et al., Topics in Catalysis 9 (1999), pages 105 to 111 . Chen et al., Science 291 (2001), 1021-1023 and DE-A 101 11 230 ,

The MOFs according to the present invention contain pores, especially micro and / or mesopores. Micropores are defined as those having a diameter of 2 nm or smaller and mesopores are defined by a diameter in the range of 2 to 50 nm, each according to the definition as they are Pure Applied Chem. 45, page 71, especially on page 79 (1976) is specified. The presence of micro- and / or mesopores can be checked by sorption measurements, these measurements taking into account the uptake capacity of the organometallic frameworks for nitrogen at 77 Kelvin DIN 66131 and or DIN 66134 determine.

The specific surface is preferably calculated according to the Langmuir model ( DIN 66131 . 66134 ) for a MOF in powder form at more than 5 m ² / g, more preferably over 10 m ² / g, more preferably more than 50 m ² / g, even more preferably more than 500 m ² / g, even more preferably more than 1000 m ² / g and more preferably more than 1500 m ² / g.

MOF shaped bodies can have a lower specific surface; but preferably more than 10 m ² / g, more preferably more than 50 m ² / g, even more preferably more than 500 m ² / g and in particular more than 1000 m ² / g.

The metal component in the framework of the present invention is preferably selected from Groups Ia, IIa, IIIa, IVa to VIIIa and Ib to VIb. Particularly preferred are Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni , Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Tl, Si, Ge, Sn, Pb, As, Sb and Bi. More preferred are Zn, Cu, Mg, Al, Ga, In, Sc, Y, Lu, Ti, Zr, V, Fe, Ni, and Co. Particularly, Cu, Zn, Al, Fe, and Co. are particularly preferred. With respect to the ions of these elements, mention is particularly made of Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Sc ³⁺ , Y ³⁺ , Ti ⁴⁺ , Zr ⁴⁺ , Hf ⁴⁺ , V ⁴⁺ , V ³⁺ , V ²⁺ , Nb ³⁺ , Ta ^{3 +} , Cr ³⁺ , Mo ³⁺ , W ³⁺ , Mn ³⁺ , Mn ²⁺ , Re ³⁺ , Re ²⁺ , Fe ³⁺ , Fe ²⁺ , Ru ³⁺ , Ru ²⁺ , Os ³⁺ , Os ²⁺ , Co ³⁺ , Co ²⁺ , Rh ²⁺ , Rh ⁺ , Ir ²⁺ , Ir ⁺ , Ni ²⁺ , Ni ⁺ , Pd ²⁺ , Pd ⁺ , Pt ²⁺ , Pt ⁺ , Cu ²⁺ , Cu ⁺ , Ag ⁺ , Au ⁺ , Zn ²⁺ , Cd ²⁺ , Hg ²⁺ , Al ³⁺ , Ga ³⁺ , In ³⁺ , Tl ³⁺ , Si ⁴⁺ , Si ²⁺ , Ge ⁴⁺ , Ge ²⁺ , Sn ⁴⁺ , Sn ²⁺ , Pb ⁴⁺ , Pb ²⁺ , As ⁵⁺ , As ³⁺ , As ⁺ , Sb ⁵⁺ , Sb ³⁺ , Sb ⁺ , Bi ⁵⁺ , Bi ³⁺ and Bi ⁺ .

Of the Term "at least bidentate organic compound" denotes an organic compound which is at least one functional Contains group that is capable of a given Metal ion at least two, preferably two coordinative bonds, and / or to two or more, preferably two metal atoms each to form a coordinative bond.

Examples of functional groups which can be used to form the abovementioned coordinative bonds are, for example, the following functional groups: -CO ₂ H, -CS ₂ H, -NO ₂ , -B (OH) ₂ , -SO ₃ H, - Si (OH) ₃ , -Ge (OH) ₃ , -Sn (OH) ₃ , -Si (SH) ₄ , -Ge (SH) ₄ , -Sn (SH) ₃ , -PO ₃ H, -AsO ₃ H , -AsO ₄ H, -P (SH) ₃ , -As (SH) ₃ , -CH (RSH) ₂ , -C (RSH) ₃ -CH (RNH ₂ ) ₂ -C (RNH ₂ ) ₃ , -CH (ROH) ₂ , -C (ROH) ₃ , -CH (RCN) ₂ , -C (RCN) ₃ where, for example, R preferably represents an alkylene group having 1, 2, 3, 4 or 5 carbon atoms, for example a methylene, ethylene , n-propylene, i-propylene, n-butylene, i-butylene, tert-butylene or n-pentylene group, or an aryl group containing 1 or 2 aromati cal cores such as 2 C ₆ rings, which may optionally be condensed and may be independently substituted with at least one each substituent, and / or which may each independently contain at least one heteroatom such as N, O and / or S. According to likewise preferred embodiments, functional groups are to be mentioned in which the abovementioned radical R is absent. In this regard, inter alia, -CH (SH) ₂ , -C (SH) ₃ , -CH (NH ₂ ) ₂ , -C (NH ₂ ) ₃ , -CH (OH) ₂ , -C (OH) ₃ , -CH (CN) ₂ or -C (CN) ₃ to call.

The at least two functional groups can in principle be bound to any suitable organic compound as long as it is ensured that that the organic compound having these functional groups for the formation of the coordinative bond and for the production of the Framework material is capable.

Prefers The organic compounds that make up the at least two are derived contain functional groups, from a saturated or unsaturated aliphatic compound or a aromatic compound or one both aliphatic and aromatic compound.

The aliphatic compound or the aliphatic part of both aliphatic as well as aromatic compound can be linear and / or branched and / or be cyclic, with several cycles per compound possible are. More preferably, the aliphatic compound contains or the aliphatic part of both aliphatic and aromatic Compound 1 to 15, more preferably 1 to 14, more preferably 1 to 13, more preferably 1 to 12, further preferably 1 to 11 and particularly preferably 1 to 10 C atoms, such as, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms. Particularly preferred here, inter alia, methane, adamantane, acetylene, ethylene or Butadiene.

The aromatic compound or the aromatic part of both aromatic and aliphatic compound may have one or more cores, such as two, three, four or five cores, wherein the cores may be separated from each other and / or at least two nuclei in condensed form. Most preferably, the aromatic compound or the aromatic moiety of the both aliphatic and aromatic compounds has one, two or three nuclei, with one or two nuclei being particularly preferred. Independently of one another, each nucleus of the compound mentioned can furthermore contain at least one heteroatom, such as, for example, N, O, S, B, P, Si, Al, preferably N, O and / or S. More preferably, the aromatic compound or the aromatic moiety of the both aromatic and aliphatic compounds contains one or two C ₆ cores, the two being either separately or in condensed form. In particular, benzene, naphthalene and / or biphenyl and / or bipyridyl and / or pyridyl may be mentioned as aromatic compounds.

Especially Preferably, the at least bidentate organic is derived Compound of a di-, tri- or tetracarboxylic acid or their sulfur analogues from. Sulfur analogues are the functional ones Groups -C (= O) SH and its tautomer and C (= S) SH, instead of one or more carboxylic acid groups are used can.

The term "derive" in the context of the present invention means that the at least bidentate organic compound can be present in the framework material in partially deprotonated or completely deprotonated form. Furthermore, the at least bidentate organic compound may contain further substituents such as -OH, -NH ₂ , -OCH ₃ , -CH ₃ , -NH (CH ₃ ), -N (CH ₃ ) ₂ , -CN and halides.

For example, dicarboxylic acids such as oxalic acid, succinic acid, tartaric acid, 1,4-butanedicarboxylic acid, 4-oxo-pyran-2,6-dicarboxylic acid, 1,6-hexanedicarboxylic acid, decanedicarboxylic acid, 1,8-heptadecanedicarboxylic acid, 1, 9-heptadecanedicarboxylic acid, heptadecanedicarboxylic acid, acetylenedicarboxylic acid, 1,2-benzenedicarboxylic acid, 2,3-pyridinedicarboxylic acid, pyridine-2,3-dicarboxylic acid, 1,3-butadiene-1,4-dicarboxylic acid, 1,4-benzenedicarboxylic acid, p-benzenedicarboxylic acid, Imidazole-2,4-dicarboxylic acid, 2-methyl-quinoline-3,4-dicarboxylic acid, quinoline-2,4-dicarboxylic acid, quinoxaline-2,3-dicarboxylic acid, 6-chloroquinoxaline-2,3-dicarboxylic acid, 4,4 '-Diaminophenylmethane-3,3'-dicarboxylic acid, quinoline-3,4-dicarboxylic acid, 7-chloro-4-hydroxyquinoline-2,8-dicarboxylic acid, diimide dicarboxylic acid, pyridine-2,6-dicarboxylic acid, 2-methylimidazole-4,5- dicarboxylic acid, thiophene-3,4-dicarboxylic acid, 2-isopropylimidazole-4,5-dicarboxylic acid, tetrahydropyran-4,4-dicarboxylic acid, perylene-3,9-dicarboxylic acid acid, perylenedicarboxylic acid, Pluriol E 200-dicarboxylic acid, 3,6-dioxaoctanedicarboxylic acid, 3,5-cyclohexadiene-1,2-dicarboxylic acid, octadicarboxylic acid, pentane-3,3-carboxylic acid, 4,4'-diamino-1,1'- diphenyl-3,3'-dicarboxylic acid, 4,4'-diaminodiphenyl-3,3'-dicarboxylic acid, benzidine-3,3'-dicarboxylic acid, 1,4-bis (phenylamino) benzene-2,5-dicarboxylic acid, 1,1'-dinaphthyl-5,5'-dicarboxylic acid, 7-chloro-8-methylquinoline-2,3-dicarboxylic acid, 1-anilinoanthraquinone-2,4'-dicarboxylic acid, polytetrahydrofuran-250-dicarboxylic acid, 1,4-bis - (carboxymethyl) piperazine-2,3-dicarboxylic acid, 7-chloroquinoline-3,8-dicarboxylic acid, 1- (4-carboxy) -phenyl-3- (4-chloro) -phenyl-pyrazoline-4,5-dicarboxylic acid 1,4,5,6,7,7-hexachloro-5-norbornene-2,3-dicarboxylic acid, phenylindane dicarboxylic acid, 1,3-dibenzyl-2-oxo-imidazolidine-4,5-dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, naphthalene-1,8-dicarboxylic acid, 2-benzoylbenzene-1,3-dicarboxylic acid, 1,3-dibenzyl 2-oxoimidazolidine-4,5-cis-dicarboxylic acid, 2,2'-biquinoline-4,4'-dicarboxylic acid, pyridine-3,4-dicarboxylic acid, 3,6,9-trioxaundecanedicarboxylic acid, O-hydroxybenzophenone dicarboxylic acid, Pluriol E 300- dicarboxylic acid, Pluriol E 400 dicarboxylic acid, Pluriol E 600 dicarboxylic acid, pyrazole-3,4-dicarboxylic acid, 2,3-pyrazinedicarboxylic acid, 5,6-dimethyl-2,3-pyrazinedicarboxylic acid, 4,4'-diaminodiphenyl ether diimide dicarboxylic acid, 4,4 '-Diaminodiphenylmethanediimide dicarboxylic acid, 4,4'-diaminodiphenylsulfonediimide dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,3-adamantanedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 8-methoxy-2,3-naphthalenedicarboxylic acid, 8-nitro-2 , 3-naphthalenecarboxylic acid, 8-sulfo-2,3-naphthalenedicarboxylic acid, anthracene-2,3-dicarboxylic acid, 2 ', 3'-diphenyl-p-terphenyl-4,4''- dicarboxylic acid, diph enyl ether-4,4'-dicarboxylic acid, imidazole-4,5-dicarboxylic acid, 4 (1H) -oxothiochromene-2,8-dicarboxylic acid, 5-tert-butyl-1,3-benzenedicarboxylic acid, 7,8-quinolinedicarboxylic acid, 4, 5-imidazoledicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, hexatriacontanedicarboxylic acid, tetradecanedicarboxylic acid, 1,7-heptadicarboxylic acid, 5-hydroxy-1,3-benzenedicarboxylic acid, pyrazine-2,3-dicarboxylic acid, furan-2,5-dicarboxylic acid, 1-Nonen-6,9-dicarboxylic acid, eicosendicarboxylic acid, 4,4'-dihydroxydiphenylmethane-3,3'-dicarboxylic acid, 1-amino-4-methyl-9,10-dioxo-9,10-dihydroanthracene-2,3- dicarboxylic acid, 2,5-pyridinedicarboxylic acid, cyclohexene-2,3-dicarboxylic acid, 2,9-dichlorofluorubin-4,11-dicarboxylic acid, 7-chloro-3-methylquinoline-6,8-dicarboxylic acid, 2,4-dichlorobenzophenone-2 ' , 5'-dicarboxylic acid, 1,3-benzenedicarboxylic acid, 2,6-pyridinedicarboxylic acid, 1-methylpyrrole-3,4-dicarboxylic acid, 1-benzyl-1H-pyrrole-3,4-dicarboxylic acid, anthraquinone-1,5-dicarboxylic acid, 3,5-pyrazoledicarboxylic acid, 2-nitrobenzene-1,4-dicarboxylic acid, heptane-1,7-dicarb onic acid, cyclobutane-1,1-dicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 5,6-dehydronorbornane-2,3-dicarboxylic acid or 5-ethyl-2,3-pyridinedicarboxylic acid,

Tricarboxylic acids like approximately

2-hydroxy-1,2,3-propanetricarboxylic acid, 7-chloro-2,3,8-quinolinetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 2-phosphono-1,2,4- butanetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, 1-hydroxy-1,2,3-propanetricarboxylic acid, 4,5-dihydro-4,5-dioxo-1H-pyrrolo [2,3-F] quinoline 2,7,9-tricarboxylic acid, 5-acetyl-3-amino-6-methylbenzene-1,2,4-tricarboxylic acid, 3-amino-5-benzoyl-6-methylbenzene-1,2,4-tricarboxylic acid acid, 1,2,3-propanetricarboxylic acid or aurintricarboxylic acid,
or tetracarboxylic acids such as
1,1-dioxide-peroxy [1,12-BCD] thiophene-3,4,9,10-tetracarboxylic acid, perylenetetracarboxylic acids such as perylene-3,4,9,10-tetracarboxylic acid or perylene-1,12-sulfone-3, 4,9,10-tetracarboxylic acid, butanetetracarboxylic acids such as 1,2,3,4-butanetetracarboxylic acid or meso-1,2,3,4-butanetetracarboxylic acid, decane-2,4,6,8-tetracarboxylic acid, 1,4,7, 10,13,16-hexaoxacyclooctadecane-2,3,11,12-tetracarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, 1,2,11,12-dodecanetetracarboxylic acid, 1,2,5,6-hexanetetracarboxylic acid, 1, 2,7,8-octantetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 1,2,9,10-decantetracarboxylic acid, benzophenonetetracarboxylic acid, 3,3 ', 4,4'-benzophenonetetracarboxylic acid, tetrahydrofurantetracarboxylic acid or cyclopentanetetracarboxylic acids such as cyclopentane 1,2,3,4-tetracarboxylic acid
to call.

All if appropriate, at least monosubstituted are particularly preferred mono-, di-, tri-, tetra- or higher-nuclear aromatic Di-, tri- or tetracarboxylic used, each the nuclei may contain at least one heteroatom, where two or more nuclei may contain identical or different heteroatoms. For example, monocarboxylic dicarboxylic acids are preferred, monocarbic tricarboxylic acids, monocarboxylic tetracarboxylic acids, diceric dicarboxylic acids, dicerated tricarboxylic acids, dicerated tetracarboxylic acids, tricarboxylic dicarboxylic acids, tricarboxylic tricarboxylic acids, tricyclic tetracarboxylic acids, tetracarboxylic dicarboxylic acids, tetracyclic tricarboxylic acids and / or tetracarboxylic tetracarboxylic acids. Suitable heteroatoms For example, N, O, S, B, P, Si, Al are preferred heteroatoms here are N, S and / or O. As a suitable substituent is in this regard including -OH, a nitro group, an amino group or a To name alkyl or alkoxy.

Especially are preferred as at least bidentate organic Compounds acetylenedicarboxylic acid (ADC), benzenedicarboxylic acids, naphthalenedicarboxylic acids, Biphenyl dicarboxylic acids such as 4,4'-biphenyl dicarboxylic acid (BPDC), Bipyridinedicarboxylic acids such as 2,2'-bipyridine dicarboxylic acids such as 2,2'-bipyridine-5,5'-dicarboxylic acid, benzene tricarboxylic acids such as 1,2,3-benzenetricarboxylic acid or 1,3,5-benzenetricarboxylic acid (BTC), adamantane tetracarboxylic acid (ATC), adamantane dibenzoate (ADB) Benzene tribenzoate (BTB), methane tetrabenzoate (MTB), adamantane tetrabenzoate or dihydroxyterephthalic acids such as 2,5-dihydroxyterephthalic acid (DHBDC) used.

All particularly preferred are isophthalic acid, Terephthalic acid, 2,5-dihydroxyterephthalic acid, 1,2,3-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid or 2,2'-bipyridine-5,5'-dicarboxylic acid used.

In addition to these at least bidentate or ganic compounds, the MOF may also comprise one or more monodentate ligands.

Suitable solvents for the preparation of the MOF include ethanol, dimethylformamide, toluene, methanol, chlorobenzene, diethylformamide, dimethyl sulfoxide, water, hydrogen peroxide, methylamine, sodium hydroxide, N-methylpolidone ether, acetonitrile, benzyl chloride, triethylamine, ethylene glycol and mixtures thereof. Other metal ions, at least bidentate organic compounds and solvents for the production of MOF are, inter alia, in US-A 5,648,508 or DE-A 101 11 230 described.

The Pore size of the MOF can be selected by choosing the appropriate Ligands and / or the at least bidentate organic Be controlled connection. Generally, the bigger the organic compound the larger the pore size is. Preferably, the pore size is from 0.2 nm to 30 nm, particularly preferred is the pore size in the range of 0.3 nm to 3 nm based on the crystalline material.

In However, a larger MOF molded body occurs Pores whose size distribution can vary. Preferably, however, more than 50% of the total pore volume, in particular more than 75%, of pores with a pore diameter of formed up to 1000 nm. Preferably, however, a majority the pore volume of pores formed from two diameter ranges. It is therefore further preferred if more than 25% of the total pore volume, in particular more than 50% of the total pore volume formed by pores is in a diameter range of 100 nm to 800 nm and if more than 15% of the total pore volume, especially more is formed as 25% of the total pore volume of pores in a diameter range of up to 10 nm. The pore distribution can be determined by mercury porosimetry.

The sorption storage 5 is cooled according to the invention to increase the absorption capacity. This is done z. B. with the aid of liquid nitrogen. To prevent a temperature increase due to heat absorption by the environment, is the Sorptionsspeicher 5 from a thermal insulation 9 enclosed.

In the embodiment shown here is the Sorptionsspeicher 5 with a first connection 11 provided with the sorption storage 5 can be filled with the gaseous hydrocarbon. To escape the gaseous hydrocarbon from the Sorptionsspeicher 5 over the first connection 11 to avoid and also to allow filling is in the first port 11 a refueling valve 13 added. The refueling valve 13 is z. B. a check valve that opens as soon as the pressure in the connecting line is greater than the pressure in the sorption 5 , A pressure in the sorption reservoir 5 which is larger than that in the connecting cable 11 causes the refueling valve 13 closes. This will avoid gas from the sorption reservoir 5 over the first connection 11 can flow out. A suitable valve as refueling valve 13 is z. B. a check valve.

Via a second connection 15 gas is released from the sorption reservoir 5 taken. To the amount and pressure of the gas that over the second port 15 to be able to adjust is in the second port 15 preferably a take-off valve 17 arranged.

To the sorption storage 5 to be able to heat up with the gas contained therein, is in Sorptionsspeicher 5 a heating element 19 added. As a heating element 19 are suitable for. B. electrical heating elements. Alternatively, it is also possible, for. B. heat exchanger as a heating element 19 use. The heating element is preferred 19 however, an electric heating element.

The device according to the invention 1 also includes a tax system 21 , With the tax system 21 becomes the heating rate of the heating element 19 controlled so that when removing gas, the temperature in the sorption 5 is increased so that a predetermined minimum pressure in the Sorptionsspeicher is not reached until reaching a maximum temperature. This is done with the help of at least one temperature sensor 23 the temperature and with the help of a pressure sensor 25 the pressure in the sorption reservoir 5 measured and the values for temperature and pressure to the control system 21 transfer.

In the case of a stepwise increase in the temperature, gaseous hydrocarbon is thus produced via the second connection until a predetermined threshold value for the pressure has been reached 15 taken. Once with the pressure sensor 25 the threshold pressure is measured by the control system 21 the heating element 19 turned on to the temperature in the sorption storage 5 to increase. For this purpose, the temperature with the help of the temperature sensor 23 detected. The pressure will continue with the pressure sensor 25 detected. Once a predetermined upper pressure limit is reached, the value in the control system 21 is stored, the heating process by switching off the heating element 19 completed. It can turn on gas via the second port 15 be removed until the pressure has reached the predetermined threshold.

If the temperature is to be increased so that the pressure remains substantially constant, pressure and temperature are measured by means of the temperature sensor 23 and the pressure sensor 25 recorded and in the tax system 21 so processed that the heating element 19 is operated such that the with the pressure sensor 25 measured pressure remains substantially constant. The detection of the temperature ensures that the maximum permissible temperature is not exceeded.

Temperature recording with the help of the temperature sensor 23 is particularly necessary to the maximum allowable temperature in the sorption 5 to determine. From the maximum permissible temperature and the minimum pressure results in the state in which the gas sampling process is terminated. The maximum temperature and the minimum pressure determine the minimum amount of gas remaining in the sorption reservoir after the removal process has ended.

In 2 the removal process is shown in a first embodiment in a storage capacity pressure diagram. Furthermore, in 2 Adsorption isotherms for methane on a Cu ₃ (BTC) ₂ -MOF (Basolite C300 STR3.5 BASF AG) shown.

On the abscissa 31 the pressure of methane is shown in bar. The ordinate 33 shows the content of methane in grams per liter of tank volume. In the diagram are a first adsorption isotherm 35 at a temperature of 195 K, a second adsorption isotherm 37 at a temperature of 248 K, a third adsorption isotherm 39 at a temperature of 273 K and a fourth adsorption isotherm at a temperature of 298 K shown. It can be seen that the storage capacity of Sorptionsspeichers decreases with increasing temperature and each can absorb a smaller amount of methane. It can also be seen that the loading of methane at low temperatures, even at low pressures, is much higher than the maximum possible loading at higher temperatures. Due to the lower possible loading at higher temperatures, methane is released from the sorption reservoir as the temperature is raised. At a temperature increase without gas removal increases the pressure in the memory at the same time. This makes it possible to remove more gas from the Sorptionsspeicher with the same pressure and increasing temperature.

In addition to the adsorption isotherms are in 2 also shows curves showing the content of methane in a tank without Sorptionsspeicher.

With reference number 43 the remaining methane content is shown in a tank without sorption storage at a temperature of 195K. Here it can be seen that the methane content increases with increasing pressure. In particular, it can be seen that there is a strong increase in the range of 40 to 60 bar. This is due to a liquefaction of methane in this pressure range. The with reference numerals 45 designated curve shows the methane content in a tank without Sorptionsspeicher at a temperature of 273 K and with reference numerals 47 Curve referred to the methane content in a tank without Sorptionsspeicher at a temperature of 289 K. The curves 43 . 45 and 47 were determined from a pVT database. In comparison, the curve shows the measured methane content in a tank without sorption storage at 298 K. It can be seen from these curves that with the same tank volume in a tank with sorption storage, a larger amount of methane can be stored than in a tank without sorption storage.

The maximum loading of the sorption storage tank results from a maximum permissible pressure 51 in the tank and the minimum temperature that is reached. To empty the reservoir, first gas is removed from the reservoir until a minimum pressure 53 is reached. The gas is removed by the arrow 55 shown. The minimum pressure 53 generally results from the pressure requirements of the gas consumer, eg. As an internal combustion engine or a fuel cell. So z. B. decrease in performance if the pressure is below the minimum pressure 53 sinks. Furthermore, it is also possible that z. B. no longer open the metering valves when the pressure is lower than the minimum pressure 53 ,

In 2 a stepwise removal of the gas is shown. For this purpose, gas is first removed from the sorption reservoir at a constant temperature. The gas is removed in each case along an adsorption isotherm. When the sorption reservoir is maximally loaded, the load decreases with decreasing pressure corresponding to the first adsorption isotherm 35 off, like this with the arrow 55 is shown. As soon as the pressure is at the minimum pressure 53 approaching, the temperature is raised. Due to the increase in temperature, the pressure increases with constant loading. This is with the arrow 57 shown. The heating is stopped upon reaching a predetermined threshold, which is above the pressure at which the removal is terminated. This is done z. B. by switching off an electrically operated heater or by stopping the heating by a heat exchanger. The upper threshold value may, for example, also correspond to the maximum permissible storage pressure.

To If the upper threshold is reached, the heating is stopped or reduced and it can be removed gaseous hydrocarbon, until the pressure approaches the lower threshold again. This is repeated until either the Sorptionsspeicher far enough is emptied as possible or a predetermined temperature is reached. The predetermined maximum temperature can z. Belly be determined from the residual amount after removal of the gaseous Hydrocarbon should remain in Sorptionsspeicher. The removal of hydrocarbon is understood also possible during heating up.

In order to avoid that the pressure at the removal under the given minimum pressure 53 Preferably, heating is started as soon as the pressure is in a range between minimum pressure 53 and a pressure which is at most 20% greater than the predetermined minimum pressure 15 is, lies.

In addition to the heating shown here 57 without gas removal, it is of course also possible that while heating gaseous hydrocarbon continues to be removed from the Sorptionsspeicher.

To further avoid that due to the increase in temperature, the pressure of the maximum allowable pressure 51 is exceeded, is preferably heated only until the maximum allowable storage pressure is reached. Exceeding the maximum permissible pressure 51 must be avoided in any case, in order to avoid damage to the tank where the tank may burst. The maximum permissible pressure 51 thus results in particular from the strength of the tank. It is also possible that the maximum pressure results from properties of the extraction valve. So it is z. B. possible that a sampling valve is used, at pressures above the maximum pressure 51 lie, can not open.

In 3 the gas removal is shown in a second embodiment. In the 3 illustrated embodiment differs from the in 2 illustrated embodiment in that the temperature is not increased gradually but a continuous increase in temperature is carried out while gaseous hydrocarbon is removed from the Sorptionsspeicher. The temperature is thereby increased so that the pressure remains substantially constant when gas is removed. This is through the withdrawal curve 59 shown. Preferably, the pressure, which is kept substantially constant by the temperature increase, in the minimum pressure 53 , This ensures that the maximum possible amount of gas is removed from the Sorptionsspeicher with minimal energy consumption by the increase in temperature.

However, while at the in 2 illustrated embodiment, a simple 2-step control is sufficient to perform the stepwise increase in temperature, in the in 3 illustrated embodiment, a continuous control to avoid that the pressure drops when removing below the minimum pressure.

At a storage temperature at a maximum loaded sorption of 195 K and a maximum temperature to which the gas is removed from the Sorptionsspeicher of 298 K, a maximum pressure of 50 bar and a minimum pressure of 10 bar results, for example, a maximum tank capacity, as with the double arrow 61 is shown.

1

contraption for storage

3

tank

5

sorption

7

jacketed

9

thermal insulation

11

first connection

13

refueling valve

15

second Connection removal valve

19

heating element

21

control system

23

temperature sensor

25

pressure sensor

31

abscissa

33

ordinate

35

Adsorption isotherm at 195 K

37

Adsorption isotherm at 248 K

39

Adsorption isotherm at 273K

41

Adsorption isotherm at 298K

43

CH ₄ content in empty tank at 195 K (pVT database)

45

CH ₄ content in empty tank at 273 K (pVT database)

47

CH ₄ content in empty tank at 298 K (pVT database)

49

CH ₄ content measured in empty tank at 298 K)

51

maximum pressure

53

minimum pressure

55

gas extraction

57

temperature increase

59

extraction curve

61

maximum tank capacity

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US Pat. No. 6,748,748 B [0003]
• US 5648508 [0038]
• - EP 0790253 A [0038]
• - DE 10111230 A [0038, 0057]
• - US 5648508 A [0057]

Cited non-patent literature

• M.O. Keeffe et al., J. Sol. State Chem., 152 (2000), pages 3 to 20 [0038]
• - H. Li et al., Nature 402 (1999), page 276 [0038]
• - M. Eddaoudi et al., Topics in Catalysis 9 (1999), pages 105 to 111 [0038]
• -. B. Chen et al, Science 291 (2001), page 1021-1023 [0038]
• -. [0038]
• - Pure Applied Chem. 45, page 71, in particular on page 79 (1976) [0039]
• - DIN 66131 [0039]
• - DIN 66134 [0039]
• - DIN 66131 [0040]
• - 66134 [0040]

Claims (14)

Method for storing gaseous hydrocarbons in a sorption reservoir ( 5 ), characterized in that the temperature of the stored hydrocarbon with filled sorption ( 5 ) is less than room temperature and greater than the vaporization temperature of the hydrocarbon. A method according to claim 1, characterized in that the temperature of the hydrocarbon during filling of the sorption ( 5 ) is less than or equal to the temperature of the stored hydrocarbon when the sorption reservoir is filled ( 5 ). Method according to claim 1 or 2, characterized in that the sorption reservoir ( 5 ) is cooled to the temperature of the gaseous hydrocarbon. Method according to one of claims 1 to 3, characterized in that for emptying the sorption storage ( 5 ) the temperature in the sorption storage ( 5 ) is increased with decreasing content of gas until reaching a maximum allowable temperature, that a predetermined minimum pressure in the sorption ( 5 ) is not fallen below. A method according to claim 4, characterized characterized in that a gradual increase in temperature is carried out, each gas at a constant temperature until reaching a predetermined setpoint for the Pressure is taken and increases when the set point, the temperature until a predetermined upper pressure limit is reached. A method according to claim 5, characterized characterized in that the predetermined upper pressure limit of the maximum permissible storage pressure corresponds. A method according to claim 4, characterized in that from reaching a predetermined pressure, the temperature in the sorption ( 5 ) is increased upon removal of gas so that the pressure remains substantially constant until a predetermined maximum allowable temperature is reached. A method according to claim 7, characterized in that the predetermined pressure, from which the temperature in the sorption storage ( 5 ) is substantially equal to the predetermined minimum pressure. Method according to one of the claims 1 to 8, characterized in that the gaseous hydrocarbon is selected from natural gas, methane, ethane, propane and butane. Particularly preferred is the gaseous hydrocarbon selected from natural gas or methane. Device for storing gaseous hydrocarbons, comprising a sorption storage ( 5 ) isolated from the environment, characterized in that the sorption reservoir ( 5 ) Contains zeolite, activated carbon or organometallic framework compounds. Apparatus according to claim 10, characterized in that the sorption storage ( 5 ) comprises a cooling device. Device according to claim 10 or 11, characterized in that a control system ( 21 ) is included with the temperature increase in Sorptionsspeicher ( 5 ) can be controlled on removal of gas so that a predetermined minimum pressure is not exceeded until reaching a maximum allowable temperature. Device according to one of claims 10 to 12, characterized in that furthermore a heating element ( 19 ), with which the sorption storage ( 5 ) can be heated. Device according to one of claims 10 to 13, characterized in that the sorption storage ( 5 ) a first connection ( 11 ) for filling and a second connection ( 15 ) for emptying