WO2007128656A1

WO2007128656A1 - Device for controlling gas purity for a gas reservoir

Info

Publication number: WO2007128656A1
Application number: PCT/EP2007/053730
Authority: WO
Inventors: Werner Gruenwald; Thorsten Allgeier; Kai Oertel; Ian Faye; Stephan Leuthner; Jan-Michael Graehn; Markus Schubert; Ulrich Mueller; Michael Hesse
Original assignee: Robert Bosch Gmbh; Basf Aktiengesellschaft
Priority date: 2006-05-04
Filing date: 2007-04-17
Publication date: 2007-11-15
Also published as: DE102006020849A1

Abstract

The invention relates to a method and a device for controlling gas purity when a gas reservoir (41), containing a sorption material (82), is filled. A heatable filter (46), whose filter material can be regenerated or replaced, is connected upstream of the gas reservoir (41). A first shut-off valve (44) is connected upstream of the filter (46) and a second shut-off valve (54) is connected upstream of the gas reservoir (41). Higher molecular hydrocarbons CxHy that have been retained by the filter (46) are fed to a consumer, bypassing the gas reservoir (41), and are introduced into a consumer line (80).

Description

description

title

Device for regulating the gas purity of a gas storage

State of the art

For the storage of gases, pressurized gas tanks are generally used today. Compressed gas tanks can be used both in stationary applications, for example for heating buildings or in mobile applications, for example in gas-powered motor vehicles. With regard to the mobile applications of pressurized gas tanks, the gas tanks are generally designed for a system pressure of 200 bar and are installed in a gaseous fuel-powered motor vehicle. The disadvantage here is the fact that special safety requirements are made of gas-powered vehicles. Another disadvantage in particular with regard to the mobile applications of pressurized gas tanks is the fact that due to safety regulations for gas tanks for motor vehicles, the gas tanks are usually designed as a cylindrical pressure vessel, the permissible capacity is only 80% of the available space. The remaining portion of the existing volume of the compressed gas storage serves as an expansion space for the gas. For driving motor vehicles used gaseous fuel forms with air a particularly good mixture and is characterized by a lower pollutant emission. Gaseous fuel is largely free of lead and sulfur compounds and has very good combustion properties with excellent mixture formation and distribution, which has an even stronger effect at low temperatures.

In previously used pressurized gas tanks for storing gaseous fuel volatile impurities play no role. However, condensable fractions may condense in the gaseous fuel, such as, for example, higher molecular weight hydrocarbons such as butane under pressure at the bottom of the gas reservoir and lead to a change in the calorific value of the gas at Gasent-.

According to current trends, adsorption storage tanks for natural gas and hydrogen are being developed as gas storage facilities. Adsorption storage becomes the gas to be stored to materials with a large internal surface, such as adsorbed zeolites and stored in this way. In the gas to be stored, such as gaseous fuel, contained impurities, such as water vapor or higher molecular weight hydrocarbons occupy adsorption sites and thereby reduce the storage capacity of the adsorption of Adsorptionsspeichers.

From WO 97/36819 an apparatus and a method for storage for the release of hydrogen from a hydrogen storage is known. The hydrogen gas is stored in a rechargeable storage and released by it. If necessary, the hydrogen gas can be taken out of the hydrogen storage. In the memory, a solid-state storage medium is added, which is in the form of a metal hydride in particulate form and does not require any treatment steps such as compaction or the like. Via divider walls, the hydrogen storage is subdivided into separate chambers, each containing a matrix formed by a suitable material, such as thermally conductive aluminum foam, which forms a number of cells. The ratio of the chamber length to the diameter of the hydrogen storage is preferably between 0.5 and 2. Within the aluminum foam formed by cells are metal hydride or other suitable for storage of hydrogen substances. The hydrogen storage device has a hydrogen extraction line, through which the hydrogen gas flows when discharged from the hydrogen storage or when feeding to the hydrogen storage. Within the hydrogen line is provided a filter which retains the metal hydride particles contained in the cells and prevents them from affecting the hydrogen gas in terms of its purity. A heat transfer surface is formed by a channel which is thermally coupled to the aluminum foam. During the addition of hydrogen during charging of the hydrogen storage or during the discharge of the hydrogen storage, the heat generated is removed by a heat removal device from the hydrogen storage.

Disclosure of the invention

The present invention has for its object to supply a gas storage, in particular an adsorption only storage gas such as natural gas or city gas, which is free of impurities.

According to the invention this object is achieved in that a gas storage for receiving gaseous fuel, such as CH ₄ or another gas, for example, for industrial applications, a particular heatable filter is connected upstream. The gas flowing into the gas storage is disturbing before entering the gas storage Contaminants, such as CO ₂ , CO and moisture, analyzed. The gas flowing in from a gas station for filling the gas reservoir passes to the gas reservoir via a first shut-off valve and the filter and another shut-off valve arranged between the filter and the gas reservoir. If the filter effect no longer exists due to an overload of the filter material with contaminants, the first shut-off valve and the second shut-off valve upstream of the gas reservoir can be closed. This ensures that only such gas enters the gas storage, which has a prescribed purity and quality.

The blocking of the first, upstream of the filter shut-off valve and the second gas storage upstream shut-off valve via a control unit. The control unit is connected to a gas sensor connected downstream of the filter and to a gas sensor arranged downstream of the gas extraction valve of the gas reservoir.

If the desired filter efficiency is no longer possible by overloading the filter with impurities, the shut-off valves upstream of the filter and the gas accumulator are closed.

In order to prevent the storage of gaseous fuel, such as CH _4, to prevent combustible gases retained in the filter, which are usually relatively high molecular weight C _x H _y , being lost for combustion, the higher molecular weight retained in the filter can be lost C _x H ₅ , optionally be supplied during operation of the gaseous fuel burning internal combustion engine. For this purpose, the filter can be provided with a heating device in order to expel the combustible gases retained therein from the filter and feed them via a metering valve to the consumer, such as, for example, a gaseous fuel-burning internal combustion engine. In the event that the combustible high molecular weight C _x H ₅ retained in the filter are supplied to the consumer, the shut-off valve upstream of the gas reservoir and the shut-off valve upstream of the filter are closed.

The filter, which may optionally be associated with a heating device for expelling higher molecular weight C _x H ₅ , may in the simplest case be designed as a cold trap. In addition, the design of the gas storage upstream filter as activated carbon filter is possible. As filter materials metal oxides such as ALO2, molecular sieves, zeolites or activated carbon can be used. For detecting the gases in front of the consumer, such as a gaseous fuel burning internal combustion engine, a calorific value or calorific value sensor can be used to control the calorific value upstream of this consumer. In addition, it is also possible to replace the calorific value or calorific value sensors in front of the consumer, such as an internal combustion engine, to use surface acoustic wave sensors, which detect higher molecular weight hydrocarbons C _x H ₅ , before flowing into the gas reservoir via the mass occupancy of the sensor surface.

To control the gas quality during operation, for example, during the expulsion of high molecular weight hydrocarbons from the filter with shut off the first and second shut-off valve may be present in the extending from the filter to the metering line before the consumer and behind the metering another gas quality sensor. This may likewise be a calorific value or calorific value sensor, or a surface acoustic wave sensor or the like.

The measures described above with reference to a gas storage for mobile applications can be used instead of, for example, a gas-powered motor vehicle or even stationary gas storage, such as industrial gas storage. The measures can also be carried out on a gas storage reservoir, for example, at a gas station, in particular if the storage of gaseous fuel provided there is a sorption reservoir. In Sorptionsspeicher, be it a gas storage for mobile applications such as in the car, for stationary applications fertilize such as a storage tank at a gas station or for industrial purposes, come in Sorptionsspeicher sorption, such as zeolites and especially Metal Organic Frameworks as sorbent materials in question ,

The gas quality sensor, which is connected downstream of the filter, can also be used without a filter in order to protect a gas reservoir received in the motor vehicle from being filled with poor quality gaseous fuel, which can be caused, for example, by a greasy gas station compressor, in which the gaseous fuel is loaded with oil fractions which may attach to the sorbent material within the gas reservoir. The sorbent material, which is preferably Metal Organic Frameworks, has a high specific surface area of at least 1000 m ² / g, to which the gaseous fuel attaches. This surface must be kept free of impurities such as CO ₂ , CO or moisture or the like in order to keep constant the storage capacity of the sorbent material, which is preferably MOF, over the operating time.

The preferred filter used may have an exchange cartridge that is easily replaceable when the filter effect is exhausted. In addition, the filter can be configured as a double filter, in which a part of the double filter is regenerated, while the others can be used. The filter can be regenerated by the heating shown above, ie the higher molecular weight hydrocarbons C _x H ₅ accumulating in the filter can be expelled therefrom by the heating device optionally assigned to the filter.

drawing

With reference to the drawing, the invention will be described below in more detail.

It shows:

1 shows a course of a desorption curve for benzene of a 1st Metal Organic Framework (MOF), plotted over time and the temperature gradient,

FIG. 2 shows the benzene desorption on a second metal organic framework, plotted over the desorption time and upon impressing a temperature gradient,

FIG. 3 shows the octane sorption on a first metal organic framework, plotted over the desorption time and upon impressing a temperature gradient,

FIG. 4 shows the octane sorption on the 2nd Metal Organic Framework, plotted over the desorption time and impressing a temperature gradient,

Figure 5 is a circuit diagram of a gas storage, in particular a Sorptionsspeichers with upstream filter element and

Figure 6 shows another embodiment of the interconnection of the gas storage.

variants

The porous organometallic framework contains at least one at least one metal ion coordinated at least bidentate organic compound. This organometallic framework (MOF) is described, for example, in US 5,648,508, EP-A-0 790 253, M. O-Keeffe et al, J. Sol. State Chem., JJ2 (2000), pages 3 to 20, H. Li et al., Nature 402 (1999), page 276, M. Eddaoudi et al., Topics in Catalysis 9 (1999), pages 105 to 111, Chen et al., Science 291 (2001), pages 1021 to 1023 and DE-A-101 11 230. The MOFs according to the present invention contain pores, in particular 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 described by Pure Applied Chem. 45_, page 71, in particular on page 79 (FIG. 1976). The presence of micro- and / or mesopores can be checked by means of sorption measurements, these measurements determining the uptake capacity of the organometallic frameworks for nitrogen at 77 Kelvin according to DIN 66131 and / or DIN 66134.

The specific surface area - calculated according to the Langmuir model (DIN 66131, 66134) for a MOF in powder form is preferably more than 5 m ² / g, more preferably more than 10 m ² / g, more preferably more than 50 m ² / g , more preferably more than 500 m ² / g, even more preferably more than 1000 m ² / g and particularly 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, IHa, IVa to Villa 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⁺ ,

, "3+ m 3+ r ^ 3 + n It 3 + ττ r3 + nt 3+ nt 2+ τ- _> 3+ τ- _> 2+ T- 3 + T-" 2+ τ- _> 3+ τ- _> 2+ / ~ v 3+ / ~ v 2+

Nb, Ta, Cr, Mo, W, Mn, Mn, Re, Re, Fe, Fe, Ru, Ru, Os, Os, 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⁺ , r C <d A ^ ⁺ , T HJg ² +, AA il3 +, fG ~ ia 3+, TIn ³⁺ , TTll ³⁺ , CSi " ⁴⁺ , CSi" ² +, ^ Ge 4+, G, ^ e 2+, oSn 4+, oSn 2+, TPiUb ⁴⁺ , TP) Ub ²⁺ , AA s ⁵⁺ , AA s ³⁺ , As ⁺ , Sb ⁵⁺ , Sb ³⁺ , Sb ⁺ , Bi ⁵⁺ , Bi ³⁺ and Bi ⁺ .

The term "at least bidentate organic compound" refers to an organic compound containing at least one functional group capable of having at least two, preferably two coordinative, bonds to a given metal ion, and / or to two or more, preferably two, metal atoms, respectively form a coordinative bond.

Functional groups by means of which the abovementioned coordinative bonds can be formed include in particular, 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 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,

Butylene, tert-butylene or n-pentylene group, or an aryl group containing 1 or 2 aromatic nuclei such as 2 Cό rings, which may be optionally condensed and may be independently substituted with at least one each substituent suitably, and / or which independently of one another may each contain at least one heteroatom, such as, for example, 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 are, 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 the organic compound having these functional groups is capable of forming the coordinative bond and the preparation of the framework.

Preferably, the organic compounds containing the at least two functional groups are derived from a saturated or unsaturated aliphatic compound or an aromatic compound or an aliphatic as well as an aromatic compound.

The aliphatic compound or the aliphatic portion of the both aliphatic and aromatic compound may be linear and / or branched and / or cyclic, wherein also several cycles per compound are possible. More preferably, the aliphatic compound or the aliphatic portion of the both aliphatic and aromatic compound contains 1 to 15, more preferably 1 to 14, further preferably 1 to 13, further preferably 1 to 12, further preferably 1 to 11 and particularly preferably 1 to 10 C atoms such as 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 C atoms. Methane, adamantane, acetylene, ethylene or butadiene are particularly preferred in this case.

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. Particularly preferably, the aromatic compound or the aromatic part of both aliphatic and aromatic matic compound one, two or three cores, with one or two cores are particularly preferred. Independently of each other, furthermore, each nucleus of the named compound may 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 portion of the both aromatic and aliphatic compound contains one or two C _ό 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.

The at least bidentate organic compound is particularly preferably derived from a di-, tri- or tetracarboxylic acid or its sulfur analogs. Sulfur analogues are the functional groups -C (= O) SH and its tautomer and C (= S) SH, which can be used instead of one or more carboxylic acid groups.

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, are examples of the present invention. 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, 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, diimidedicarboxylic 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, 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, r-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-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) -phenylpyrazoline

4,5-dicarboxylic acid, 1, 4,5,6,7,7, hexachloro-5-norbornene-2,3-dicarboxylic acid, phenylindane-1-carboxylic 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-pyrazine dicarboxylic 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'-DiphenyI-p-terphenyl-4,4 "-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, imidazole-4,5-dicar Bonsäure, 4 (1 H) - oxothiochromene-2,8-dicarboxylic acid, 5-tert-butyl-1, 3-benzenedicarboxylic acid, 7,8-

Quinoline dicarboxylic acid, 4,5-imidazoledicarboxylic acid, 4-cyclohexane-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-nonene-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-methylpyrrolo-3,4-dicarboxylic acid, 1-benzyl-1H-pyrrole-3,4-dicarboxylic acid, anthraquinone -l, 5-dicarboxylic acid, 3, 5-pyrazoldicarboxylic acid, 2-nitrobenzene-1, 4-dicarboxylic acid, heptane-1, 7-dicarboxylic 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 such as

2-hydroxy-l, 2,3-propanetricarboxylic acid, 7-chloro-2,3,8-quinoline tricarboxylic 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-per [1,12-BCD] thiophene-3,4,9,10-tetracarboxylic acid, perylenetetracarboxylic acids such as perylene-3,4,9,10-tetracarboxylic acid or perylene-1,15-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-benzene tetracarboxylic acid,

1, 2, 11, 12-dodecantetracarboxylic acid, 1, 2,5,6-hexanetetracarboxylic acid, 1, 2,7,8-octane-tetracarboxylic acid, 1, 4,5,8-naphthalenetetracarboxylic acid, 1, 2, 9, 10 Decantetracarboxylic acid, benzophenone tetracarboxylic acid, 3,3 ', 4,4'-benzophenone tetracarboxylic acid, tetrahydrofuran-tetracarboxylic acid or cyclopentanetetracarboxylic acids such as cyclopentane-1,2,3,4-tetracarboxylic acid

to call.

Very particular preference is given to using at least mono-, di-, tri-, tetra- or higher-nuclear aromatic di-, tri- or tetracarboxylic acids, where each of the cores can contain at least one heteroatom, where two or more nuclei have identical or different heteroatoms may contain. For example, preference is given to monocarboxylic dicarboxylic acids, monocarboxylic tricarboxylic acids, monocarboxylic tetracarboxylic acids, dicercaric dicarboxylic acids, dicercaric tricarboxylic acids, dicercaric tetracarboxylic acids, tricyclic dicarboxylic acids, tricarboxylic tricarboxylic acids, tricarboxylic tetracarboxylic acids, tetracyclic dicarboxylic acids, tetracyclic tricarboxylic acids and / or tetracyclic tetracarboxylic acids. Suitable heteroatoms are, for example, N, O, S, B, P, Si, Al. Preferred heteroatoms here are N, S and / or O. A suitable substituent in this regard is, inter alia, -OH, a nitro group, an amino group or an alkyl to name or alkoxy.

Especially preferred as the at least bidentate organic compounds are acetylenedicarboxylic acid (ADC), benzenedicarboxylic acids, naphthalenedicarboxylic acids, biphenyldicarboxylic acids such as 4,4'-biphenyldicarboxylic acid (BPDC), bipyridine dicarboxylic acids such as 2,2'-bipyridinedicarboxylic acids such as 2,2 '-Bipyridin-

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), methanetetrabenzoate (MTB), adamantane trenches - zoate or dihydroxyterephthalic acids such as 2,5-dihydroxyterephthalic acid

(DHBDC) used. 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 are very particularly preferably used.

In addition to these at least bidentate organic 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 hereof. Further metal ions, at least bidentate organic compounds and solvents for the preparation of MOF are described inter alia in US Pat. No. 5,648,508 or DE-A 101 11 230.

The pore size of the MOF can be controlled by choice of the appropriate ligand and / or the at least bidentate organic compound. Generally, the larger the organic compound, the larger the pore size. The pore size is preferably from 0.2 nm to 30 nm, more preferably the pore size is in the range from 0.3 nm to 3 nm, based on the crystalline material.

In a MOF shaped body, however, larger pores also occur whose size distribution can vary. Preferably, however, more than 50% of the total pore volume, in particular more than 75%, of pores having a pore diameter of up to 1000 nm is formed. Preferably, however, a majority of the pore volume is formed by pores of 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, is formed by pores which are in a diameter range of 100 nm to 800 nm and if more than 15% of the total pore volume, in particular more than 25% of the total pore volume is formed by pores in a diameter range of up to 10 nm. The pore distribution can be determined by means of mercury porosimetry.

The illustration according to FIG. 1 shows the desorption of benzene on a first metal organic framework, such as, for example, cu-benzenetricarboxylic acid, plotted over the desorption time and upon impressing a temperature gradient.

FIG. 1 shows a desorption time, designated by reference numeral 10, in minutes. Reference numeral 20 denotes the temperature scale at ⁰ C. After a time of t = ti, a steadily rising temperature gradient is reached until a maximum temperature is reached. generated by T = 250 ⁰ C. Reference numeral 30 denotes a desorption curve for benzene, which reaches a pronounced maximum 32 after a time of t = t ₂ desorption time and then drops again as the temperature rises. According to the Desorptionsverlaufes 30 for benzene shown in Figure 1 this is desorbed by impressing the temperature gradient shown in Figure 1 after a desorption of about t ₃ for the most part from the present in the gas storage sorbent material.

The illustration according to FIG. 2 shows a desorption curve of benzene on a second metal organic framework, plotted over the desorption time and the temperature.

Analogously to the representation according to FIG. 1, reference numeral 10 denotes the desorption time, while reference numeral 20 denotes the temperature scale. Reference numeral 30 denotes the desorption curve 30 of benzene which, as shown in FIG. 2, is further characterized by a pronounced first maximum 34 after a desorption time t = t ₄ and by a further, second maximum 36 after a desorption time of t = t ₅ leaves. The second maximum 36, which is shown in FIG. 2, finds its cause in a condensation process, which can be caused, for example, by an overdose.

Also in the illustration according to FIG. 2, after a desorption time of t = t _6, a temperature gradient is applied whose maximum is given by a temperature of T = 300 ^° C. The temperature gradient shown in FIG. 2 has a steadily increasing slope.

The illustration according to FIG. 3 shows the desorption of octane on a first metal organic framework. Also, as shown in FIG. 3, a temperature gradient is impressed on the desorption material. After a desorption time of t = t ₆ , the temperature rises steadily to a maximum temperature of T = 250 ⁰ C. The desorption curve 30 according to the illustration in FIG. 3 is characterized by a maximum 38 for the octane sorption of the 1st metal organic framework, which occurs after a desorption time t = t ₅ . Thereafter, the Desorptionsverlauf 30 is falling sharply.

Finally, FIG. 4 shows the desorption course of octane on a second metal organic framework, plotted over the desorption time and the temperature.

From the illustration according to FIG. 4, it can be seen that the desorption curve 30 of octane from the second metal organic framework used has its maximum 40 after one Desorption time of t = t ₇ reached. Thereafter, the desorption curve 30 assumes a strongly decreasing course, although the temperature continues to rise steadily. The temperature gradient impressed in FIG. 4 rises from a desorption time of t = t ₈ from a temperature of T = 30 ^° C. to a maximum temperature of T = 250 ^° C.

Based on the representation of Figure 5, the basic structure of a device for controlling the gas purity of a gas storage is described in more detail.

The illustration according to FIG. 5 shows that a filter 46 is preceded by a filter 46. The filter 46 may be equipped as an activated carbon filter, as a cold trap or with a replaceable filter cartridge. If the filter effect of the filter cartridge used in the filter 46 exhausted, this can be easily replaced. Instead of a filter 46 provided with an exchangeable replacement cartridge, it is also possible to use a double filter, wherein one filter element of the double filter is used in each case and that in each case another can be regenerated, for example via an optional heating device 48. The waste heat of the internal combustion engine, for example via its heated cooling medium for heating the filter 46 or for regeneration of an unused part, of a filter 46 designed as a double filter could also be used. Furthermore, the heated cooling medium of the internal combustion engine heats up the used part of a filter 46 in the form of a double filter. If adequate regeneration by heating alone is not possible, backwashing can be carried out during heating. As filter materials in addition to the already mentioned activated carbon and zeolites or metal organic framework such as MOF's in question. As filter material, other suitable filter material can be used in the filter 46 in addition to the sorption material, such as metal oxide (A-102) and molecular sieves. The use of sorbent material 82 is not mandatory.

The filter 46 is connected upstream of a first shut-off valve 44; The reference numeral 42 designates a gas station-side supply or a connection for a stationary gas storage 41. Between the filter 46 and the gas reservoir 41 there is a first gas quality sensor 52 and a second, the gas reservoir 41 upstream second shut-off valve 54. In the gas storage 41 is a sorbent material 82, which is preferably a Metal Organic Framework (MOF). The gas reservoir 41 is emptied via a gas extraction valve 56. From optionally provided with a heater 48 filter 46 extends a line for expelling high molecular hydrocarbon vapors C _x H ₅ , to a metering valve 50, which opens behind the gas sampling valve 56 and a second gas quality sensor 48 in a consumer line 80. The consumer line 80 can For example, in mobile applications to a gaseous fuel operated internal combustion engine of a motor vehicle extend.

In the embodiment variant of the interconnection of the gas accumulator 41 shown in FIG. 6, the gas evacuation valve 56 connected downstream of the gas accumulator 41 can be dispensed with. For this purpose, the second shut-off valve 54 and the metering valve 60 are designed as a 3/2-way valve, which are connected via line 50 directly to each other.

The interaction of the illustrated valves 44, 54, 56 and 60 can be coordinated by a control unit 78. To the control unit 78, a signal line 64 extends from the second gas quality sensor 58. Furthermore, a signal line 70 extends to the control unit 78 from the first gas quality sensor 52. From the control unit 78, a control line 66 extends to the gas sampling valve 56, a control line 62 to the metering and each a control line 68 and 74 to the second shut-off valve 54 and the first shut-off valve 44, which is upstream of the filter 46. Furthermore, a drive line 76 extends to the connection point of a refueling unit. Optionally, communication, i. E. establish a data exchange between the control unit 78 and the gas station. For example, a signal for switching off the refueling process can be transmitted via the control line 76 when the tank is completely filled. Furthermore, a signal can be transmitted via the control line 76, which indicates the need for a filter change in the filter 46 and a signal which initiates a closing of a valve.

By the circuit diagram shown in Figure 5 of a device for Gasgüteregelung for a gas storage 41, gas flows from the filling station side supply line 42 to the first shut-off valve 44. If this is open, the gas passes to the filter 46 and an optionally opened second shut-off valve 54 in the gas storage 41. The gas is analyzed before the inlet into the gas reservoir 41 for checking the filter efficiency of the filter 46 by means of the first gas quality sensor 52 for interfering impurities out , The gas quality level, which is determined via the first gas quality sensor 52, is transmitted via the signal line 70 to the control unit 78. If the filter effect of the filter 46 is not sufficient, for example because a filter cartridge is completely loaded with contaminants, both the first shut-off valve 44 and the second shut-off valve 54 in front of the gas reservoir 41 are closed via the control lines 68 and 74. This ensures that only such gas enters the gas reservoir 41, which has a predefinable gas quality. The filter 46 can be regenerated by means of a heater 46 optionally assigned to the filter 46. In order to prevent the combustible gases retained in the filter 46, which as a rule are relatively high molecular weight hydrocarbons C _x H ₅ , from being lost for combustion, for example in an internal combustion engine, the high molecular weight gases retained in the filter 46 can operate be passed via the line 50 to the metering valve 60. To expel the higher molecular weight hydrocarbons C _x H _y , the filter 46 is heated by the heater 48, or ügber the cooling medium with which the internal combustion engine is cooled. The supply of heated cooling medium to the heater 48 can be controlled via a thermostat. It is also possible for a plurality of filters 46 to be arranged one behind the other or parallel to one another, through which the gaseous fuel flows. Furthermore, in the case of filters formed as double filters, their filter parts can in each case be flowed through alternately, wherein the respective unused filter part can be regenerated within the scope of a heating process by a separate heating device 48 or the heated cooling medium of the internal combustion engine.

In this case, both the first shut-off valve 44 in front of the filter 46 and the second shut-off valve 54 in front of the gas reservoir 41 are closed. Behind the metering valve 60, the vapors of relatively high molecular weight hydrocarbons C _x H _{5 are} fed into the consumption line 80. For detecting the gas quality in front of the consumer, ie in the consumer line 80, a calorific value or calorific value sensor can be used to control the calorific value and a surface acoustic wave sensor can be used as the second gas quality sensor 58.

By means of the second gas sensor 58, depending on the embodiment of the sensor, a mass occupation of the sensor surface with relatively high molecular weight hydrocarbons C _x H ₅ can be detected.

During the Ausheizvorgangs the filter 46 may be required to control the gas quality during operation, a further gas quality sensor 58 in front of the consumer. The further, second gas quality sensor 58 can be both a calorific value sensor and a calorific value sensor or the aforementioned surface acoustic wave sensor.

By heating the filter material of the filter 46, which material may be activated carbon zeolites or also a sorbent material 82 such as the first MOF or the second MOF, and the second shut-off valve 54 is prevented from being contained in the gaseous fuel Impurities storage places for a gaseous Occupy fuel such as CH ₄ on the sorbent material 82 in the interior of the gas storage 41, ie, the storage capacity seen over the operating time of the gas storage 41, steadily decreases. On the other hand, it is achieved by the solution proposed by the invention that the high molecular hydrocarbons C _x H ₅ retained in the filter 46 are nevertheless made accessible for recycling in a consumer by feeding them via the metering valve 60 into the consumer line 80, for example in the event the internal combustion engine of a gaseous fuel vehicle has warmed up.

While the foregoing has been made for a gas storage 41 serving, for example, as a tank in a motor vehicle for receiving gaseous fuel, these embodiments apply equally to a gas storage 41 for stationary applications. The gas storage 41, which is provided in the context in question with a sorbent 82 such as Cu-MOF or Zn-MOF, for example, can serve as a storage for gaseous fuel at a gas station or used as a gas storage tank for industrial applications become.

Claims

claims

1. A method for controlling the gas purity of a gas, in particular gaseous fuel for internal combustion engines, upon infesting a gas reservoir (41), in which a sorption material (82) is received, with the following method steps:

a) determining the quality of a gaseous fuel with a first gas quality sensor (52),

b) the closing of a gas storage (41) upstream of the shut-off valve

(54), depending on the determined quality of the gaseous fuel and

c) the expulsion of high molecular weight hydrocarbons C _x H ₅ , from the gaseous fuel and their supply to the consumer.

2. The method according to claim 1, characterized in that according to step a) depending on the quality of the gaseous fuel, a filter (46) upstream shut-off valve (44) is closed.

3. The method according to claim 1, characterized in that method step c) is carried out with closed shut-off valves (44, 56).

4. The method according to claim 1, characterized in that the expulsion of relatively high molecular weight hydrocarbons C _x H ₅ , takes place via a heating of the filter 46 with a heated cooling medium of the internal combustion engine.

5. The method according to claims 1 and 3, characterized in that in step c) the switching on and off of a heating device (48) or a controlled operation of a heating device (48).

6. A device for controlling the gas purity when attacking a gas reservoir (41) in which a sorption material (82) is received and the gas reservoir (41) is associated with a heatable filter (46), characterized in that retained in the filter (46) flammable gases are fed into a consumer line (80) bypassing the gas reservoir (40).

7. The device according to claim 6, characterized in that the filter (46) has a first shut-off valve (44) and the gas reservoir (41) is preceded by a second shut-off valve (54).

8. The device according to claim 7, characterized in that the first shut-off valve (44) a first gas quality sensor (52) is connected downstream, which is connected via a signal line (70) with a control unit (48).

9. The device according to claims 7 and 8, characterized in that a heating of the filter (46) depending on the signal of the gas quality sensor (52) takes place and upon heating of the filter (46), the first and the second shut-off valve (44, 54 ) are closed and a metering valve (60) is opened.

10. The device according to claim 6, characterized in that the filter (46) comprises an exchangeable filter cartridge or is designed as a double filter.

11. The device according to claim 6, characterized in that activated carbon, zeolites, metal oxides such as AIO2 or metal-organic framework (MOF) are used as the filter material.

12. The device according to claim 6, characterized in that in the consumer line (80) is arranged a gas sampling valve (56) of the gas reservoir (41) and the metering valve (60) downstream second Gasgütesensor (58).

13. Device according to claims 8 or 12, characterized in that the first and / or second gas quality sensor (52, 58) is designed as a calorific value or calorific value sensor or as a surface acoustic wave sensor.

14. Use of the device according to one or more of claims 6 to 13 for controlling the gas purity when infested a gas storage (41) containing a sorbent material (82) for mobile applications in a motor vehicle, for gas filling stations or gas boiler in industrial use.