Utilization of pollutants from internal combustion engines

Abstract

Nitrogen oxides formed in combustion engines are recycled such that the nitrogen oxides can be utilized for producing liquid or solid chemicals. The nitrogen oxides are recycled by a method including an adsorber material adsorbing nitrogen oxides from an exhaust-gas stream of the combustion engine, removing the adsorber material laden with nitrogen oxides, desorbing the adsorbed nitrogen oxides from the adsorber material, and converting the nitrogen oxides desorbed from the adsorber material into liquid or solid nitrogen-containing compounds.

Claims

1. A system for recycling nitrogen oxides formed in a combustion engine, the system comprising: an adsorber unit having an adsorber material including at least one zeolite configured to adsorb nitrogen oxides from an exhaust-gas stream of the combustion engine, the adsorber unit being configured as an exchangeable cartridge or such that adsorber material laden with nitrogen oxides is removable from the adsorber unit so that another adsorber material, unladen with nitrogen oxides, can be accommodated in the adsorber unit, in a non-destructive manner; a desorption module, detached from the combustion engine and provided outside of the exhaust-gas stream, configured to desorb, from the adsorber material, nitrogen oxides that have been adsorbed by the adsorber material; and a reaction unit, detached from the combustion engine and provided outside of the exhaust-gas stream, configured to convert the nitrogen oxides desorbed by the desorption module into liquid or solid nitrogen-containing compounds.

2. The system according to claim 1, wherein the adsorber unit is configured such that adsorber material laden with nitrogen oxides is removable from the adsorber unit, and the adsorber unit is configured as a reclosable container from which the adsorber material is removable after opening of the reclosable container.

3. The system according to claim 1, wherein the desorption module is configured to heat the adsorber unit, or feed hot water vapor, hot gas or a liquid solvent to the adsorber unit, and thereby desorb nitrogen oxides from the adsorber unit, or the desorption module is configured to heat the adsorber material laden with nitrogen oxides, or to treat the adsorber material with hot water vapor, hot gas or a liquid solvent, and thereby desorb nitrogen oxides from the adsorber material.

4. The system according to claim 1, wherein the reaction unit includes a reactor to convert nitrogen oxides to form nitric acid.

5. The system according to claim 4, wherein the reaction unit includes another reactor to convert the nitric acid with ammonia to form ammonium nitrate.

6. A system, for recycling nitrogen oxides formed in a combustion engine, the system comprising: an adsorber unit having an adsorber material including at least one zeolite configured to adsorb nitrogen oxides from an exhaust-gas stream of the combustion engine; a desorption module, detached from the combustion engine and provided outside of the exhaust-gas stream, configured to desorb, from the adsorber material, nitrogen oxides that have been adsorbed by the adsorber material; and a reaction unit, detached from the combustion engine and provided outside of the exhaust-gas stream, configured to convert the nitrogen oxides desorbed by the desorption module into liquid or solid nitrogen-containing compounds, the reaction unit including a reactor to convert nitrogen oxides to form nitric acid.

7. The system according to claim 6, wherein the reaction unit includes another reactor to convert the nitric acid with ammonia to form ammonium nitrate.

8. The system according to claim 6, wherein the desorption module is configured to heat the adsorber unit, or feed hot water vapor, hot gas or a liquid solvent to the adsorber unit, and thereby desorb nitrogen oxides from the adsorber unit, or the desorption module is configured to heat the adsorber material laden with nitrogen oxides, or to treat the adsorber material with hot water vapor, hot gas or a liquid solvent, and thereby desorb nitrogen oxides from the adsorber material.

9. A method for the recycling of nitrogen oxides formed in a combustion engine, the method comprising: adsorbing, in an adsorber unit having an adsorber material including at least one zeolite, nitrogen oxides from an exhaust-gas stream of the combustion engine, the adsorber unit being configured as an exchangeable cartridge or such that adsorber material laden with nitrogen oxides is removable from the adsorber unit so that another adsorber material, unladen with nitrogen oxides, can be accommodated in the adsorber unit, in a non-destructive manner; removing the adsorber unit having the adsorber material laden with nitrogen oxides or removing the adsorber material laden with nitrogen oxides from the adsorber unit, to a desorption module, the desorption module being detached from the combustion engine and provided outside of the exhaust-gas stream; desorbing, by the desorption module, the adsorbed nitrogen oxides from the adsorber material; and converting, by a reaction unit detached from the combustion engine and provided outside of the exhaust-gas stream, the nitrogen oxides desorbed from the adsorber material into liquid or solid nitrogen-containing compounds.

10. The method according to claim 9, wherein the liquid or solid nitrogen-containing compounds include nitrates.

11. The method according to claim 10, wherein the nitrates include ammonium nitrates.

12. The method according to claim 9, wherein the at least one zeolite includes ZSM-5, zeolite Y, or mordenite.

13. The method according to claim 9, wherein the adsorber unit is configured as the exchangeable cartridge, the adsorber unit is provided in an exhaust tract of the combustion engine, and the method comprises: removing the adsorber unit from the exhaust tract; and providing another adsorber unit, having an adsorber material unladen with nitrogen oxides, in the exhaust tract of the combustion engine.

14. The method according to claim 9, wherein the adsorber unit is such that the adsorber material laden with nitrogen oxides is removable from the adsorber unit, the adsorber material is provided in a container of the adsorber unit, and the method comprises: removing the adsorber material laden with nitrogen oxides from the container; and providing another adsorber material, unladen with nitrogen oxides, in the container.

15. The method according to claim 9, wherein removing the adsorber unit having the adsorber material laden with nitrogen oxides or removing the adsorber material laden with nitrogen oxides from the adsorber unit, is performed in response to reaching a capacity of the adsorber unit for accommodating nitrogen oxides.

16. The method according to claim 9, wherein desorbing the adsorbed nitrogen oxides from the adsorber material includes: treating the adsorber material with at least one of heat, hot vapor, hot gas, and a liquid solvent, and separating the nitrogen oxides from the adsorber material.

17. The method according to claim 16, wherein the treating of the adsorber material with the at least one of heat, hot vapor, hot gas, and the liquid solvent, is performed at a temperature of 200 C. or less.

18. The method according to claim 17, further comprising drying the adsorber material at a temperature of 200 C. or less.

19. The method according to claim 9, further comprising after removing the adsorber unit having the adsorber material laden with nitrogen oxides or after removing the adsorber material laden with nitrogen oxides from the adsorber unit, storing the adsorber material laden with nitrogen oxides at a collection point together with a plurality of other adsorber materials laden with nitrogen oxides, and desorbing the adsorbed nitrogen oxides from the adsorber material includes desorbing the adsorbed nitrogen oxides from the adsorber material together with desorbing the adsorbed nitrogen oxides from the plurality of other adsorber materials.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects and advantages will become more apparent and more readily appreciated from the following description of the example embodiments which will be described further with reference to various examples and the associated drawing, in which the single drawing is a schematic illustration of an embodiment of the system described herein for the recycling of nitrogen oxides formed in a combustion engine.

DETAILED DESCRIPTION

(2) Reference will now be made in detail to examples which are illustrated in the accompanying drawing.

(3) The single drawing schematically shows an embodiment of the system 10 for the recycling of nitrogen oxides formed in a combustion engine 11.

(4) In the embodiment illustrated, the combustion engine 11 is arranged in a vehicle. The exhaust-gas stream 12 of the combustion engine 11 flows through the exhaust tract of the vehicle. In the exhaust tract, there is arranged an adsorber unit 13, for example an exchangeable cartridge containing an adsorber material, which is designed for the adsorption of nitrogen oxides (NO.sub.x) from the exhaust-gas stream 12. During the operation of the combustion engine 11, an adsorption of NO.sub.x occurs in the adsorber unit 13 of the vehicle. During travel, the exhaust-gas stream 12 is conducted through the adsorber unit 13, which contains, for example, adsorber material which can bind NO.sub.x by adsorption. The adsorber unit 13 is thus charged with NO.sub.x and can accommodate up to the accommodation limit of the adsorber unit NO.sub.x.

(5) An exchange of the adsorber unit 13 is performed at the latest after the accommodation limit has been reached, that is to say when the adsorber material has been fully saturated with NO.sub.x. Either the adsorber unit 13 as a whole is exchanged, or the adsorber material in the adsorber unit 13 of the vehicle is exchanged for new, unladen material. The adsorber unit 13 is therefore, for example, designed as an exchangeable cartridge, or permits a removal of the laden adsorber material and the replacement of the laden material with unladen adsorber material without great installation effort, and for example without the adsorber unit 13 being destroyed in the process.

(6) The material laden with NO.sub.x can be collected and temporarily stored at a collecting point, in order for relatively large quantities of the laden material to be made available for the next operation, and for the recycling process to thereby be made more efficient.

(7) The adsorber unit 13 or the laden adsorber material contained therein is then transferred into a desorption module 14. In the desorption module 14, the nitrogen oxides adsorbed in the adsorber unit 13 are desorbed. In one variant, the adsorber material laden with NO.sub.x is treated either with heat, hot vapor, hot gas or a liquid solvent (for example water). The NO.sub.x changes into the vapor or liquid phase, and the adsorber material remains unchanged. The adsorber material must possibly be dried before being reused. During the desorption and during the drying, moderate temperatures of at most 200 C. should be used. The separated-off NO.sub.x is fed to a reaction unit 15 for further conversion.

(8) In the reaction unit 15, the desorbed nitrogen oxides are converted to form a reaction product 20. For example, in the reaction unit 15 the desorbed nitrogen oxides are converted to form liquid or solid nitrogen-containing compounds 20. For example, the NO.sub.x may be introduced into the production chain of nitric acid, nitrates or non-aqueous, NO.sub.2-based solvents.

(9) In one variant, the nitrogen oxides NO.sub.x are firstly converted in the reaction unit 15 to form nitric acid HNO.sub.3. The nitric acid is subsequently converted with ammonia NH.sub.3 to form ammonium nitrate NH.sub.4NO.sub.3, which is used for example as nitrogen fertilizer.

(10) A description has been provided with reference to embodiments thereof and examples, but it will be understood that variations and modifications can be effected within the spirit and scope of the claims which may include the phrase at least one of A, B and C as an alternative expression that means one or more of A, B and C may be used, contrary to the holding in Superguide v. DIRECTV, 358 F3d 870, 69 USPQ2d 1865 (Fed. Cir. 2004).