PROCESS FOR IMPROVING THE QUALITY OF HYDROGEN-BEARING ORGANIC LIQUIDS

Abstract

The present invention relates to a process for producing hydrogen from a liquid capable of being used in at least one hydrogenation/dehydrogenation cycle, said process comprising at least one step wherein said liquid is brought into contact with a filtering agent. The invention also relates to the use of a filtering agent for the purification of a liquid capable of being used in at least one hydrogenation/dehydrogenation cycle, in a hydrogen production process.

Claims

1-8. (canceled)

9. A process for producing hydrogen from a liquid capable of being used in at least one hydrogenation/dehydrogenation cycle, said process comprising at least one step wherein said liquid is brought into contact with a filtering agent.

10. The process as claimed in claim 9, wherein said liquid is an aromatic liquid, optionally at least partially or completely hydrogenated.

11. The process as claimed in claim 9, wherein the filtering agent is chosen from filtering agents comprising one or more compounds chosen from minerals based on silicates, carbonates, coal, and also mixtures of two or more of these minerals in any proportions.

12. The process as claimed in claim 9, wherein the filtering agent is selected from the group consisting of clays, zeolites, diatomaceous earths, ceramics, carbonates, and coal derivatives, and also mixtures of two or more of them, in any proportions.

13. The process as claimed in claim 9, wherein the fluid that can be used in the process of the present invention corresponds to the general formula (1):
(A-X).sub.n-B  (1) wherein: A and B, which are identical or different, represent, independently of one another, an aromatic ring, optionally completely or partially hydrogenated, optionally comprising at least one heteroatom, and optionally substituted by one or more saturated or partially or completely unsaturated hydrocarbon radicals comprising from 1 to 20 carbon atoms, X represents a spacer group, chosen from a single bond, an oxygen atom, a sulfur atom, the divalent radical —(CRR′).sub.m—, the divalent radical >C═CRR′, and the divalent radical —NR″—, or else when n is other than 0 (zero), X forms, with the aromatic rings to which it is attached, a saturated or unsaturated ring comprising from 4 to 10 ring members, among which one or more of them may be a heteroatom selected from the group consisting of oxygen, nitrogen, and sulfur, it being possible for said saturated or unsaturated ring to further be substituted by one or more hydrocarbon chains comprising from 1 to 30 carbon atoms, R and R′, which are identical or different, are chosen, independently of one another, from hydrogen and a saturated or partially or completely unsaturated hydrocarbon radical comprising from 1 to 6 carbon atoms, R″ represents a saturated or partially or completely unsaturated hydrocarbon radical comprising from 1 to 6 carbon atoms, m represents an integer of between 1 and 4, endpoints included, and n can be equal to 0 or represents an integer equal to 1, 2 or 3, with the restriction that, when n is equal to 0, B is substituted by one or more hydrocarbon radicals, defined above.

14. The process as claimed in claim 9, wherein the fluid that can be used in the process of the present invention is selected from the group consisting of: benzyltoluene (BT), dibenzyltoluene (DBT), the partially or completely hydrogenated homologs thereof, and also mixtures thereof in any proportions, diphenylethane (DPE) and isomers thereof, ditolyl ether (DT), isomers thereof, and mixtures thereof, phenyl xylyl ethane (PXE), isomers thereof and mixtures thereof, monoxylylxylenes and dixylylxylenes, isomers thereof and mixtures thereof, 1,2,3,4-tetrahydro-(1-phenylethyl)naphthalene, diisopropylnaphthalene, monoisopropylbiphenyl and isomers thereof, phenylethylphenylethane (PEPE) and isomers thereof, N-ethylcarbazole, phenylpyridines, tolylpyridines, diphenylpyridines, dipyridylbenzenes, dipyridinetoluenes, and the partially or completely hydrogenated homologs thereof, and mixtures of two or more of them, in any proportions.

15. The method as claimed in claim 9, wherein the step of purifying the organic liquid by contacting with the filtering agent is carried out before the dehydrogenation step.

16. Purification of a liquid capable of being used in at least one hydrogenation/dehydrogenation cycle, in a hydrogen production process as defined in claim 9 comprising using a filtering agent.

Description

EXAMPLES

Example 1

[0058] 11 g of a filtering agent and 350 g of LOHC organic liquid are introduced into a vacuum flask. The contacting is carried out for a period of 16 hours with magnetic stirring, under nitrogen.

[0059] Tests are carried out with DBT (Jarytherm® DBT sold by the company ARKEMA) as LOHC organic liquid. 0.1% by weight of dicyclohexylmethanol (supplier: Sigma-Aldrich) is added to the DBT, and the combined mixture is brought into contact with a filtering agent. The test is carried out with the following filtering agents: [0060] Micro-sorb® 16/30 LVM attapulgite from BASF, and [0061] Siliporite® MK30B0 molecular sieve (supplier: ARKEMA)

[0062] At the end of the contacting under stirring for 16 hours, the mixture is filtered under vacuum on a Büchner funnel in order to retain the solids. The filtered liquid is then analyzed (liquid chromatography). It is observed that the residual dicyclohexylmethanol impurity content is of the order of 0.02% by weight or less, thus demonstrating the effectiveness of the filtering agent for the purification of a fluid capable of being used in at least one hydrogenation/dehydrogenation cycle.