Stratified charge combustion engine

Abstract

The invention relates to an at least partly stratified (such as at least partly dual stratified) charge combustion engine, especially CAI (combustion assisted ignition), HCC, HCSI and HCCI engine, in which the combustion of a hydrocarbon containing fuel generating a flame emitting photon is operated in a chamber with a wall provided with a cerium oxide-carbon containing coating, said coating further comprising at least comprising oxides of the followings elements Pr, Nd, La and at least Y and/or Zr. The engine of the invention enables a catalytic reduction of NOx exhaust rate.

Claims

1. A catalyst precursor for a burning catalyst for catalytic burning a carbon and hydrogen containing combustible in an oxygen containing gaseous medium in a burning zone of a burning chamber with at least one burning catalytic wall contacting the burning zone, said burning catalyst being a cerium oxide-carbon containing catalyst coating on the said burning catalytic wall, whereby said cerium oxide-carbon containing catalyst coating further comprises at least oxides of the followings elements Pr, Nd, La, Y and Zr, whereby said cerium oxide-carbon containing catalyst coating is adapted for controlling the formation of H+ species at least on the burning catalytic wall of the burning chamber, while controlling the hydrogen branching reactions by catalysing use of oxygen atoms from at least one metal oxide with the metal selected from the group consisting of Ce, Pr, Nd, La, Y and Zr for reacting with hydrogen H.sub.2 for the formation of H.sub.2O on the burning catalytic wall of the burning chamber, whereby the Z and Y weight metal content expressed as oxide in the total metal weight content of metal elements selected from Ce, Pr, Nd, La, Y and Zr expressed as oxide is at least 10% by weight, in which the catalyst precursor is such that the relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 of the cerium-carbon containing catalyst coating with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: 25 to 50%, Pr, as Pr.sub.6O.sub.11: 2 to 10%, La, as La.sub.2O.sub.3: 15 to 37%, Nd, as Nd.sub.2O.sub.3: 4 to 15%, Y, as Y.sub.2O.sub.3: 5 to 15%, Zr, as ZrO.sub.2: 5 to 25%.

2. The catalyst precursor of claim 1, in which the catalyst precursor is such that the relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 of the cerium-carbon containing catalyst coating with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: from 35 to 45%, Pr, as Pr.sub.6O.sub.11: from 2.5 to 6% La, as La.sub.2O.sub.3: from 20 to 32% Nd, as Nd.sub.2O.sub.3: from 5 to 13% Y, as Y.sub.2O.sub.3: from 8 to 12% Zr, as ZrO.sub.2: from 10 to 17%.

3. The catalyst precursor of claim 1, which further comprises an aluminium containing component selected from the group consisting of aluminium oxide, aluminosilicate, alumino phospho silicate, and mixtures thereof.

4. The catalyst precursor of claim 1, which is in the form of particles with a size of less than 10 m.

5. The catalyst precursor of claim 1, which is in the form of particles with a size in the nano range.

6. An at least partly stratified charge combustion engine, in which the combustion of a hydrocarbon containing fuel generating a flame emitting photon is operated in at least one burning zone of a burning chamber with at least one burning catalytic wall contacting said at least one burning zone, whereby said at least one burning catalytic wall is provided with a cerium oxide-carbon containing burning catalyst coating, whereby said cerium oxide-carbon containing burning catalyst coating further comprises at least oxides of the followings elements Pr, Nd, La, Y and Zr, whereby said cerium oxide-carbon containing burning catalyst coating is adapted for controlling the formation of H+ species at least on the at least one burning catalytic wall of the burning chamber, while controlling the hydrogen branching reactions by catalysing use of oxygen atoms from at least one metal oxide with the metal selected from the group consisting of Ce, Pr, Nd, La, Y and Zr for reacting with hydrogen H.sub.2 for the formation of H.sub.2O on the at least one burning catalytic wall of the burning chamber, whereby the Z and Y weight metal content expressed as oxide in the total metal weight content of metal elements selected from Ce, Pr, Nd, La, Y and Zr expressed as oxide is at least 10% by weight, in which said cerium oxide-carbon containing burning catalyst coating is such that the relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 of said cerium oxide-carbon containing burning catalyst coating with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: 25 to 50%, Pr, as Pr.sub.6O.sub.11: 2 to 10%, La, as La.sub.2O.sub.3: 15 to 37%, Nd, as Nd.sub.2O.sub.3: 4 to 15%, Y, as Y.sub.2O.sub.3: 5 to 15%, Zr, as ZrO.sub.2: 5 to 25%.

7. The engine of claim 6, in which the cerium oxide-carbon containing burning catalyst coating is such that the relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 of the cerium-carbon containing catalyst coating with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: from 35 to 45%, Pr, as Pr.sub.6O.sub.11: from 2.5 to 6% La, as La.sub.2O.sub.3: from 20 to 32% Nd, as Nd.sub.2O.sub.3: from 5 to 13% Y, as Y.sub.2O.sub.3: from 8 to 12% Zr, as ZrO.sub.2: from 10 to 17%.

8. The engine of claim 6, in which the cerium oxide-carbon containing burning catalyst coating is selected among the group consisting of cerium oxide-carbon containing burning catalyst coating adapted for capturing photons emitted by the flame with wavelength from 6500 to 7500 , cerium oxide-carbon containing burning catalyst coating adapted for capturing 5 to 25% of the photons with wavelength from 6500 to 7500 emitted by the flame having a temperature higher than 800 C., cerium oxide-carbon containing burning catalyst coating adapted for ensuring a photon amplified spectrum emission radiation at least at a temperature comprised between 500 C. and 800 C., and combinations thereof.

9. The engine of claim 6, which comprises at least four successive steps, namely an intake step for charging the burning chamber with a gaseous medium comprising at least oxygen and nitrogen, a compression step in which said at least oxygen and nitrogen is compressed, a combustion step in the combustion chamber, and an exhaust step for the exhaust of gases present in the combustion chamber, whereby at least during one step selected from the group of the intake step and compression step, the said cerium oxide-carbon containing burning catalyst coating is adapted for uptake of oxygen atoms of the gaseous medium at least at a temperature comprised between 100 and 400 C.

10. The engine of claim 9, in which the cerium oxide-carbon containing burning catalyst coating is adapted for uptake of hydrogen atoms at least at temperature comprised between 300 and 700 C.

11. The engine of claim 9, in which the cerium oxide-carbon containing burning catalyst coating acts as catalyst for the reaction of oxygen stored in the cerium oxide-carbon containing burning catalyst coating with hydrogen components selected from H.sub.2 and hydrogen species for the formation of water at least at temperature above 500 C. and at pressure higher than 30 10.sup.5 Pa.

12. The engine of claim 6, which comprises at least four successive steps, namely an intake step for charging the burning chamber with a gaseous medium comprising at least oxygen and nitrogen, a compression step in which said at least oxygen and nitrogen is compressed, a combustion step of a hydrocarbon containing fuel in the combustion chamber, and an exhaust step for the exhaust of gases present in the combustion chamber, whereby at least during one step selected from the group of the intake step and compression step, the said cerium oxide-carbon containing burning catalyst coating is adapted for uptake of oxygen atoms of the gaseous medium at a temperature comprised between 100 and 400 C., and in which the hydrocarbon containing fuel is converted into carbon containing species or molecules and into hydrogen and hydrogen species, at least at temperature above 500 C. and pressure above 20 10.sup.5 Pa.

13. The engine of claim 12, in which the said cerium oxide-carbon containing burning catalyst coating is adapted for reducing at least by 50 mole % of the hydrogen H.sub.2 contacting the said cerium oxide-carbon containing burning catalyst coating into species selected from the group consisting of free H species, free OH species, and mixtures thereof, at temperature above 500 C. and pressure above 20 10.sup.5 Pa.

14. The engine of claim 12, which comprises cylinders and at least one moving piston per cylinder, whereby at least one element selected form the group consisting of cylinders and pistons has a face directed towards the burning chamber, whereby said face directed towards the burning chamber is at least partly an alumino containing face provided the said cerium oxide-carbon containing burning catalyst coating.

15. The engine of claim 6, in which at least 50% of the carbon present in the said cerium oxide-carbon containing burning catalyst coating is in the form of units selected from the group consisting of graphene units, graphane units and combinations thereof.

16. The engine of claim 6, in which the said cerium oxide-carbon containing burning catalyst coating is adapted for controlling the formation of carbon particles in the form of porous graphite at least on the burning catalytic wall of the burning chamber.

17. The engine of claim 6, in which the said cerium oxide-carbon containing burning catalyst coating is adapted for emitting in function of the temperature rays with wave lengths in the violet range, rays with wavelengths in the blue range, rays with wave lengths in the green range, rays with wave lengths in the yellow range, as well as rays with wave lengths in the red range.

18. The engine of claim 6, which is an at least partly dual stratified charge combustion engine, having two opposite surfaces in relative movement the one with respect to the other, said two opposite surfaces being provided with the said cerium oxide-carbon containing burning catalyst coating.

19. The engine of claim 6, being an opposed-piston engine comprising at least one cylinder in each of which a first piston with a first cross section with a first diameter is moving along a first axis and a second piston with a second cross section with a second diameter equal or different from the first diameter is moving along a second axis parallel to or corresponding to the first axis, whereby said first piston and said second piston are reciprocating along to each other between a first position in which the said first and second pistons are close the one to the other in the cylinder considered, whereby defining in said cylinder considered a small volume between the said first and second pistons, and a second position in which the first and second pistons are away the one with respect to the other so as to define therebetween a second volume in the cylinder considered which is greater than the first volume, whereby each cylinder is provided with a catalytic open element located within the small volume of the cylinder considered, said open element separating the said first volume into a first zone directed towards the first piston and a second zone directed towards the second piston, while defining one or more open channels extending between the first zone and the second zone, said one or more passages defining an open cross section defining an open surface within a plane perpendicular to the first axis and second axis which is comprised between 0.2 and 0.8 times the average cross section of the first and second piston, whereby at least the one or more channels of the catalytic open element defines the at least one burning catalytic wall provided with the said cerium oxide carbon containing burning catalyst coating.

20. The engine of claim 19, in which the catalytic open element has a plurality of distinct channels with a minimum open cross section of at least 0.5 cm.sup.2, and in which the catalytic open element is made at least partly in a temperature ceramic like material.

21. The engine of claim 19, which comprises a plurality of cylinders and a central axis provided with a first wobble plate and a second wobble plate, a first series of pistons being turned to a first wobble plate and connected to said first wobble plate by means of a first series of rods, while a second series of pistons are turned to the second wobble plate and are connected to said second wobble plate by means of a second series of rods.

22. The engine of claim 6, comprising adjacent to said at least one burning catalytic wall, one injector selected among the group consisting of injectors for the admission of a combustible material, injectors for the admission of water vapour, and combinations thereof.

23. A burning catalytic wall comprising a support comprising a cerium oxide-carbon containing burning catalyst coating, in which said cerium oxide-carbon containing burning catalyst coating is such that the relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 of said cerium oxide-carbon containing burning catalyst coating with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: 25 to 50%, Pr, as Pr.sub.6O.sub.11: 2 to 10%, La, as La.sub.2O.sub.3: 15 to 37%, Nd, as Nd.sub.2O.sub.3: 4 to 15%, Y, as Y.sub.2O.sub.3: 5 to 15%, Zr, as ZrO.sub.2: 5 to 25%.

24. A regeneration support for regeneration of a burning catalytic wall comprising a catalytic support comprising a cerium oxide-carbon containing burning catalyst coating, in which said cerium oxide-carbon containing burning catalyst coating is such that the relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 of said cerium oxide-carbon containing burning catalyst coating with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: 25 to 50%, Pr, as Pr.sub.6O.sub.11: 2 to 10%, La, as La.sub.2O.sub.3: 15 to 37%, Nd, as Nd.sub.2O.sub.3: 4 to 15%, Y, as Y.sub.2O.sub.3: 5 to 15%, Zr, as ZrO.sub.2: 5 to 25% in which said regeneration support comprises a top layer with metals selected from Ce, Pr, La, Nd, Y and Zr, whereby the said metals expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: 25 to 50%, Pr, as Pr.sub.6O.sub.11: 2 to 10%, La, as La.sub.2O.sub.3: 15 to 37%, Nd, as Nd.sub.2O.sub.3: 4 to 15%, Y, as Y.sub.2O.sub.3: 5 to 15%, Zr, as ZrO.sub.2: 5 to 25%.

25. An at least partly stratified combustion chamber comprising at least two successive distinct burning zones, and a gas outlet, for burning a at least carbon containing combustible material in presence of an oxygen containing gaseous medium selected from air and oxygen enriched air, whereby said combustion chamber comprises a first burning zone provided with at least one inlet for the at least carbon containing combustible material to be burnt into a flue gaseous medium comprising some solid particles, and with at least one inlet for the admission of the oxygen containing gaseous medium, whereby said first burning zone is extended at least with a collecting catalytic channel system for collecting at least partly the flue gaseous medium issued from the first burning zone, whereby said collecting catalytic channel system is provided with a series of guiding catalytic channels extending each between a first open end directed towards the first burning zone, said first open end having an open surface, and a second open end directed towards the gas outlet of the combustion chamber, said guiding catalytic channels being provided each with a means for forming at least one restricted passage adjacent to its second open end, said restricted passage of each guiding catalytic channel in consideration having an open surface which is comprised between 25% and 90% of the open surface of the guiding catalytic channel in consideration adjacent to its first open end, whereby each guiding catalytic channel of said series of guiding catalytic channels is provided with a cerium oxide-carbon containing burning catalyst coating which further comprises at least oxides of the followings elements Pr, Nd, La, Y and Zr, whereby said cerium oxide-carbon containing burning catalyst coating is adapted for controlling the formation of H+ species at least on the at least one burning catalytic wall of the burning chamber, while controlling the hydrogen branching reactions by catalysing use of oxygen atoms from at least one metal oxide with the metal selected from the group consisting of Ce, Pr, Nd, La, Y and Zr for reacting with hydrogen H.sub.2 for the formation of H.sub.2O on the at least one burning catalytic wall of the burning chamber, whereby the Z and Y weight metal content expressed as oxide in the total metal weight content of metal elements selected from Ce, Pr, Nd, La, Y and Zr expressed as oxide is at least 10% by weight, in which said cerium oxide-carbon containing burning catalyst coating is such that the relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 of said cerium oxide-carbon containing burning catalyst coating with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: 25 to 50%, Pr, as Pr.sub.6O.sub.11: 2 to 10%, La, as La.sub.2O.sub.3: 15 to 37%, Nd, as Nd.sub.2O.sub.3: 4 to 15%, Y, as Y.sub.2O.sub.3: 5 to 15%, Zr, as ZrO.sub.2: 5 to 25%.

26. The combustion chamber of claim 24, in which the cerium oxide-carbon containing burning catalyst coating is such that the relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 of the cerium-carbon containing catalyst coating with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: from 35 to 45%, Pr, as Pr.sub.6O.sub.11: from 2.5 to 6% La, as La.sub.2O.sub.3: from 20 to 32% Nd, as Nd.sub.2O.sub.3: from 5 to 13% Y, as Y.sub.2O.sub.3: from 8 to 12% Zr, as ZrO.sub.2: from 10 to 17%.

27. The combustion chamber of claim 24, in which the cerium oxide-carbon containing burning catalyst coating is selected among the group consisting of cerium oxide-carbon containing burning catalyst coating adapted for capturing photons emitted by the flame with wavelength from 6500 to 7500 , cerium oxide-carbon containing burning catalyst coating adapted for capturing 5 to 25% of the photons with wavelength from 6500 to 7500 emitted by the flame having a temperature higher than 800 C., cerium oxide-carbon containing burning catalyst coating adapted for ensuring a photon amplified spectrum emission radiation at least at a temperature comprised between 500 C. and 800 C., and combinations thereof.

28. The combustion chamber of claim 25, in which the guiding catalytic channels have each a minimal open cross section of at least 2.5 cm.sup.2.

29. The combustion chamber of claim 28, in which the guiding catalytic channels have each a minimal open cross section from 5 cm.sup.2 to 20 cm.sup.2.

30. The combustion chamber of claim 25, in which the guiding catalytic channels are made at least partly in a temperature resistant ceramic like material having a wall which is provided with the cerium oxide-carbon containing burning catalyst coating having a thickness from 50 m up to 10 mm.

31. The combustion chamber of claim 25, which is associated with a system adapted for the admission of air or oxygen enriched air within the first burning zone and/or in the second burning zone.

32. The combustion chamber of claim 25, which is associated to at least one injector for the admission of water vapour within the first burning zone.

33. A combustion chamber which comprises at least one element selected from the group consisting of a fuel injector, a water vapour injector, a spark plug, a sensor comprising at least a core provided with a cerium oxide-carbon containing burning coating, in which said cerium oxide-carbon containing burning catalyst coating is such that the relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 of said cerium oxide-carbon containing burning catalyst coating with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: 25 to 50%, Pr, as Pr.sub.6O.sub.11: 2 to 10%, La, as La.sub.2O.sub.3: 15 to 37%, Nd, as Nd.sub.2O.sub.3: 4 to 15%, Y, as Y.sub.2O.sub.3: 5 to 15%, Zr, as ZrO.sub.2: 5 to 25%.

34. The chamber of claim 32, in which the cerium oxide-carbon containing burning catalyst coating is such that the relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 of the cerium-carbon containing catalyst coating with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: from 35 to 45%, Pr, as Pr.sub.6O.sub.11: from 2.5 to 6% La, as La.sub.2O.sub.3: from 20 to 32% Nd, as Nd.sub.2O.sub.3: from 5 to 13% Y, as Y.sub.2O.sub.3: from 8 to 12% Zr, as ZrO.sub.2: from 10 to 17%.

35. A process of burning a combustible material selected from the group consisting of coal, biomass combustible, fuel, combustible waste material and mixtures thereof in presence of air or oxygen enriched air within a combustion chamber comprising at least two successive distinct burning zones, and a gas outlet, for burning a at least carbon containing combustible material in presence of an oxygen containing gaseous medium selected from air and oxygen enriched air, whereby said combustion chamber comprises a first burning zone provided with at least one inlet for the at least carbon containing combustible material to be burnt into a flue gaseous medium comprising some solid particles, and with at least one inlet for the admission of the oxygen containing gaseous medium, whereby said first burning zone is extended at least with a collecting catalytic channel system for collecting at least partly the flue gaseous medium issued from the first burning zone, whereby said collecting catalytic channel system is provided with a series of guiding catalytic channels extending each between a first open end directed towards the first burning zone, said first open end having an open surface, and a second open end directed towards the gas outlet of the combustion chamber, said guiding catalytic channels being provided each with a means for forming at least one restricted passage adjacent to its second open end, said restricted passage of each guiding catalytic channel in consideration having an open surface which is comprised between 25% and 90% of the open surface of the guiding catalytic channel in consideration adjacent to its first open end, whereby each guiding catalytic channel of said series of guiding catalytic channels is provided with a cerium oxide-carbon containing burning catalyst coating which further comprises at least oxides of the followings elements Pr, Nd, La, Y and Zr, whereby said cerium oxide-carbon containing burning catalyst coating is adapted for controlling the formation of H+ species at least on the at least one burning catalytic wall of the burning chamber, while controlling the hydrogen branching reactions by catalysing use of oxygen atoms from at least one metal oxide with the metal selected from the group consisting of Ce, Pr, Nd, La, Y and Zr for reacting with hydrogen H.sub.2 for the formation of H.sub.2O on the at least one burning catalytic wall of the burning chamber, whereby the Z and Y weight metal content expressed as oxide in the total metal weight content of metal elements selected from Ce, Pr, Nd, La, Y and Zr expressed as oxide is at least 10% by weight, in which said cerium oxide-carbon containing burning catalyst coating is such that the relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 of said cerium oxide-carbon containing burning catalyst coating with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: 25 to 50%, Pr, as Pr.sub.6O.sub.11: 2 to 10%, La, as La.sub.2O.sub.3: 15 to 37%, Nd, as Nd.sub.2O.sub.3: 4 to 15%, Y, as Y.sub.2O.sub.3: 5 to 15%, Zr, as ZrO.sub.2: 5 to 25%.

36. A process of producing mechanical energy by burning a hydrocarbon containing fuel into an air containing gaseous medium in a least partly stratified charge combustion engine, in which the combustion of a hydrocarbon containing fuel generating a flame emitting photon is operated in at least one burning zone of a burning chamber with at least one burning catalytic wall contacting said at least one burning zone, whereby said at least one burning catalytic wall is provided with a cerium oxide-carbon containing burning catalyst coating, whereby said cerium oxide-carbon containing burning catalyst coating further comprises at least oxides of the followings elements Pr, Nd, La, Y and Zr, whereby said cerium oxide-carbon containing burning catalyst coating is adapted for controlling the formation of H+ species at least on the at least one burning catalytic wall of the burning chamber, while controlling the hydrogen branching reactions by catalysing use of oxygen atoms from at least one metal oxide with the metal selected from the group consisting of Ce, Pr, Nd, La, Y and Zr for reacting with hydrogen H.sub.2 for the formation of H.sub.2O on the at least one burning catalytic wall of the burning chamber, whereby the Z and Y weight metal content expressed as oxide in the total metal weight content of metal elements selected from Ce, Pr, Nd, La, Y and Zr expressed as oxide is at least 10% by weight, in which said cerium oxide-carbon containing burning catalyst coating is such that the relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 of said cerium oxide-carbon containing burning catalyst coating with respect to total weight of the said metals selected from Ce, Pr, La, Nd, Y and Zr, expressed as oxide CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3, and ZrO.sub.2 are: Ce, as CeO.sub.2: 25 to 50%, Pr, as Pr.sub.6O.sub.11: 2 to 10%, La, as La.sub.2O.sub.3: 15 to 37%, Nd, as Nd.sub.2O.sub.3: 4 to 15%, Y, as Y.sub.2O.sub.3: 5 to 15%, Zr, as ZrO.sub.2: 5 to 25%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a comparative engine bench testing graph showing the torque versus the rpm for an engine of the invention with respect to the same engine without the catalyst coating;

(2) FIG. 2A is a schematic view of one cylinder of a piston-opposite engine with the piston in a close position;

(3) FIG. 2B is a schematic view of one cylinder of a piston-opposite engine with the piston in an away position;

(4) FIG. 3 is an enlarged view of the catalytic element present in the cylinder;

(5) FIG. 4 is a schematic perspective view of a wobble plate connected to a series of pistons, said wobble plate being mounted on one end of the plurality of cylinders;

(6) FIG. 5 is a schematic view of a burning installation of the invention; and

(7) FIG. 6 is another schematic view of a burning installation of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(8) The present invention is an improvement of the technology disclosed in WO2006017915, U.S. Pat. Nos. 7,482,303, 7,188,470, EP1590555B1, and U.S. Pat. No. 7,723,257, the content of which is incorporated herein by reference.

(9) Homogeneous charge combustion is according to the state of the art, the way to increase fuel efficiency of the car engine. Car companies have then developed several systems with computer control. However, all said systems have shown their limits, as unable to achieve correctly the goals of consumption, particle emission, etc.

(10) The invention has for subject matter an engine provided with a heterogeneous catalyst enabling a live control of the combustion, even in case of large regime variation.

(11) The combustion chamber of the engine has been coated with a catalyst precursor.

(12) The precursor used was a mix of nano scale particles possibly dispersed in a wax or liquid, the composition of said mix being:

(13) 1. nano carbon primary particles with a size of less than 10 nm (possibly agglomerated into a structure with a size of less than 500 nm. Said nano carbon primary particles are present in the precursor mix at a rate of 10 to 50% by weight, advantageously from 15 to 30% by weight, preferably about 20% by weight. Instead of using carbon nano particles as such, a wax possibly with carbon nano particles can be used. The carbon particles are preferably comprising some particles forming a two dimensional graphene and/or graphane structure, most particularly a mono layered two dimensional graphene and/or graphane structure.

(14) 2. a mix of metal oxide particles, especially of nanoparticles (particles with a size of less than 200 nm, preferably at least partly less than 50 nm. Said mix of metal particles comprises advantageously with respect to the total mix of said metal oxide particles (as weight %): Ce (as CeO.sub.2): 25 to 50%, preferably from 35 to 45%, Pr (as Pr.sub.6O.sub.11): 2 to 10%, preferably from 2.5 to 6% La (as La.sub.2O.sub.3): 15 to 37%, preferably from 20 to 32% Nd (as Nd.sub.2O.sub.3): 4 to 15%, preferably from 5 to 13% Y (as Y.sub.2O.sub.3): 5 to 15%, preferably from 8 to 12% Zr (as ZrO.sub.2): 5 to 25%, preferably from 10 to 17% Al (as Al.sub.2O.sub.3): 0 to 10%, preferably from 1% to 5% Si (as SiO.sub.2): 0 to 10%, preferably from 0.5 to 5% (Said silicon can be in the form of liquid or soluble tetra ethoxy silane, in a solvent system, such as methanol, ethanol, etc.)
The mix of nano oxide particles is advantageously a mix of nano oxide particles with a weight average size of more than 100 nm and of nano oxide particles with a weight average size of less than 70 nm, the weight ratio nano oxide particle with a weight average size greater than 100 nm/nano particles with a weight average size lower than 70 nm being comprised between 5:1 and 1:5, advantageously between 4:1 and 2:1.

(15) 3. possibly a wax or liquid system, for enabling some adhesion of the particles on the surface to be coated, said wax or liquid being preferably molecules comprising carbon and hydrogen, as well as preferably oxygen atoms.

(16) the weight ratio wax/mix of metal oxide particles is advantageously greater than 2, such as comprised from 2.5 up to 6. The precursor was used for coating (for example by brushing, blowing, spraying, etc.) the wall of the combustion chambers and piston heads of the engine. The engine was made in an aluminium-based alloy. After said coating, the engine was driven with a fuel for 30 minutes. After said driving of the engine, the excess of catalyst was removed.

(17) The catalyst coating had a thickness of less than about 70 nm, with metal particles homogeneously dispersed. On the tube face of the combustion cylinders, substantially no catalyst was present or catalyst with a very small thickness.

(18) The engine was then tested.

(19) The following observations were thus found:

(20) high thermal stability of the catalyst

(21) high pressure stability

(22) high hydrogen stability

(23) working of the engine possible with different cetane number or octane number

(24) high ionic conductivity of the coating

(25) possible ignition control at different compression ratio from 6 up to more than 15, such as 20 or more, for example 22;

(26) possibility to burn at least partly the carbon and the hydrogen from the fuel separately, namely a large portion of the fuel carbon in the volume of the chamber (comprising the plasma zone adjacent to the catalyst coating(s), i.e. in a N2 enriched environment with respect to air), and a large portion of the fuel hydrogen on or in the catalyst coating(s) (i.e. namely in a O2 rich environment or in a reduced N2 environment with respect to air) High oxygen storage capacity, with high uptake and release oxygen rate High hydrogen storage capacity

(27) Possible down sizing of the filter, due to less small particle emissions, as well as down sizing of the three way catalyst exhaust

(28) Possibility to use a filter with large pore size

(29) Possibility to reduce pressure drop in the exhaust, at the level of the filter, as well as at the level of the three way catalyst

(30) quicker activation of the three way catalyst

(31) stable working of the catalyst during time, whereby less catalyst rejuvenation is needed

(32) possible working of the engine with lambda value higher than 1.3, such as higher than 1.4, such as from 1.4 to 1.3, such as from 1.5 to 2.1.

(33) improved post treatment

(34) less NOx

(35) low HC content in the exhaust gases less carbon particles exhaust (especially substantially no small sized carbon particles exhaust, such as substantially no carbon particle with a size of less than 5 m) no soot formation in the combustion chamber no soot deposit in the exhaust pipe high water vapour exhaust. Lower fuel consumption Higher global amount of free electrons in the combustion chamber The combustion was a dual stratified combustion with two opposite surfaces provided with a cerium-carbon containing coating.

(36) The engine was working with a fuel direct injection system, as well as preferably with a liquid water (as micro droplets) direct injection into the combustion chamber, such system are for example systems like the K-Jetronic range of systems of Bosch GmbH and WI (Water Injection) of Bosch GmbH. Water injection technologies are disclosed in U.S. Pat. Nos. 5,174,247, 6,067,964 and 6,092,514.

(37) The following results were observed: lower fuel consumption, lower NOx emission, lower small carbon particles emission, better, improved working of the engine (less vibrations), better working of the filter and exhaust treatment system, etc.

(38) The engine was an engine with compression ignition. It was observed that it was possible to increase the compression ratio before ignition in a spark ignition engine as well as for compression ignition engine, with respect to currently used ignition compression ratio. Moreover, possible ignition was possible with a spark plug within a large range of compression ratio.

(39) As the pressure drop in the exhaust converter system and filter was reduced with respect to the pressure drop in the exhaust converter system and filter of the current engines, while ensuring a high level of removal of carbon particles and/or conversion of toxic NOx molecules, a better air filling of the combustion chamber was possible with the engine of the invention. Moreover, when the air intake valve and the exhaust valve are both in open position, air can more easily flow through the combustion chamber of the engine of the invention, ensuring in this way an oxygen uptake by the catalyst coating, as well as a cooling of the combustion chamber, and even a high scavenging of exhaust gases.

(40) In view of the lower pressure drop in the exhaust converter system, exhaust gases can be better used for driving into rotation of a turbine (for which ever purposes), when required and/or for EGR (exhaust gas recycling) purposes. Due to the low level of carbon particles content, EGR is better performing and the EGR system is not subject to clogging problems

(41) The engine could also be an engine with spark ignition or with other means for controlling the ignition.

(42) The engine can also be provided with Bosch like injectors for injecting water drops or droplets and/or water vapour in the air intake (before and/or after the air butterfly valve in the manifold, and/or directly within the combustion chamber).

(43) The catalyst coating of the invention can thus be considered as being a highly coordinated selective, oxidising and reducing self supported redox catalytic system, whereby selective oxidising and selective reducing can vary or be controlled in function of temperature and photon emission.

(44) FIG. 1 is a comparative engine bench testing graph showing the torque (Nm) versus the rpm for an engine of the invention (dashed lines or catalysed burning) with respect to the same engine without the catalyst coating (continuous line, or conventional burning). Brake specific fuel consumption levels are expressed in grams (double lines). The tested vehicle was a Volvo engine, 5 cylinders, 2.4 l, with natural aspiration and porthole injection.

(45) With respect to the embodiment of FIGS. 2A, 2B, 3 and 4, the following can be stated.

(46) The invention has for subject matter a piston opposite engine provided with a heterogeneous catalyst enabling a live control of the combustion, even in case of large regime variation.

(47) The combustion chamber of the engine associated with two reciprocating pistons is provided with an intermediary catalytic open element coated with a catalyst or a catalyst precursor. Possibly, the inner wall and/or surfaces of the cylinder is also provided with a catalytic coating or catalyst precursor.

(48) FIG. 2A or 2B shows a cylinder 1 of a piston opposite engine (comprising a plurality of cylinders mounted parallel to each other). Each cylinder 1 is associated to a first piston 2 with a first cross section with a first diameter is moving along a first axis A and a second piston 3 with a second cross section with a second diameter equal or different from the first diameter moving along a second axis parallel to the first axis (in this case corresponding to the axis A), whereby said first piston 2 and said second piston 3 are reciprocating along to each other between a first position (FIG. 2A) in which the said first and second pistons 2,3 are close the one to the other in the cylinder considered 1, whereby defining in said cylinder considered a small volume between the said first and second pistons 2,3, and a second position (FIG. 2B) in which the first and second pistons are away the one with respect to the other so as to define therebetween a second volume in the cylinder considered which is greater than the first volume, whereby each cylinder is provided with a catalytic open element 4 located within the small volume of the cylinder considered, said open element 4 separating the said first volume into a first zone 5 directed towards the first piston 2 and a second zone 6 directed towards the second piston 3, while defining one or more open channels 7 extending between the first zone 5 and the second zone 6, said one or more passages 7 defining an open cross section defining an open surface within a plane perpendicular to the first axis and second axis which is comprised between 0.2 and 0.8 times (advantageously 0.3 and 0.7, preferably between 0.4 and 0.6, such as from 0.5 to 0.6) the average cross section of the first and second piston, whereby at least the one or more channels of the catalytic element is provided with a cerium oxide-carbon containing coating 8.

(49) The catalytic element is provided with a injector 10 for fuel injection, and another 11 for water vapour injection.

(50) The combustion chamber comprises one or more fuel injectors 100, a water vapour injectors 101, spark plugs 102, and sensors 103, each comprising at least a core provided with a cerium oxide-carbon containing coating, said coating of the element further comprising at least comprising oxides of the followings elements Pr, Nd, La and at least Y and/or Zr, whereby said cerium oxide-carbon containing coating with the oxides of the followings elements Pr, Nd, La and at least Y and/or Zr, is adapted for controlling the formation of H+ species on the wall and/or surfaces of the chamber, while controlling the hydrogen branching reactions by catalysing the use of oxygen atoms from Ce, Pr, Nd, La and at least Y and/or Zr oxides for reacting with hydrogen H.sub.2 for the formation of H.sub.2O on the wall and/or surfaces of the chamber, whereby the weight metal content of the metal element selected from Y, Zr and mix thereof expressed as oxide in the total metal weight content of metal elements selected from Ce, Pr, Nd, La, Y and Zr expressed as oxide is at least 10%, advantageously at least 15%, preferably from 16 to 40%, most preferably from 20 to 30%.

(51) The catalytic element or core is for example a support (alumino silicate, alumina silico phosphate, ceramic, etc.) provided with a catalyst coating or a precursor coating suitable for generating a catalyst coating.

(52) The precursor used was a mix of nano scale particles possibly dispersed in a wax or liquid, the composition of said mix being:

(53) 1. nano carbon primary particles with a size of less than 10 nm (possibly agglomerated into a structure with a size of less than 500 nm. Said nano carbon primary particles are present in the precursor mix at a rate of 10 to 50% by weight, advantageously from 15 to 30% by weight, preferably about 20% by weight. Instead of using carbon nano particles as such, a wax possibly with carbon nano particles can be used. The carbon particles are preferably comprising some particles forming a two-dimensional graphene and/or graphane structure, most particularly a mono layered two dimensional graphene and/or graphane structure.

(54) 2. a mix of metal oxide particles, especially of nanoparticles (particles with a size of less than 200 nm, preferably at least partly less than 50 nm. Said mix of metal particles comprises advantageously with respect to the total mix of said metal oxide particles (as weight %): Ce (as CeO.sub.2): 25 to 50%, preferably from 35 to 45%, Pr (as Pr.sub.6O.sub.11): 2 to 10%, preferably from 2.5 to 6% La (as La.sub.2O.sub.3): 15 to 37%, preferably from 20 to 32% Nd (as Nd.sub.2O.sub.3): 4 to 15%, preferably from 5 to 13% Y (as Y.sub.2O.sub.3): 5 to 15%, preferably from 8 to 12% Zr (as ZrO.sub.2): 5 to 25%, preferably from 10 to 17% Al (as Al.sub.2O.sub.3): 0 to 10%, preferably from 1% to 5% Si (as SiO.sub.2): 0 to 10%, preferably from 0.5 to 5% (Said silicon can be in the form of liquid or soluble tetra ethoxy silane, in a solvent system, such as methanol, ethanol, etc.)
The mix of nano oxide particles is advantageously a mix of nano oxide particles with a weight average size of more than 100 nm and of nano oxide particles with a weight average size of less than 70 nm, the weight ratio nano oxide particle with a weight average size greater than 100 nm/nano particles with a weight average size lower than 70 nm being comprised between 5:1 and 1:5, advantageously between 4:1 and 2:1.

(55) 3. possibly a wax or liquid system, for enabling some adhesion of the particles on the surface to be coated, said wax or liquid being preferably molecules comprising carbon and hydrogen, as well as preferably oxygen atoms.

(56) the weight ratio wax/mix of metal oxide particles is advantageously greater than 2, such as comprised from 2.5 up to 6.

(57) The precursor was used for coating (for example by brushing, blowing, spraying, etc.) the wall and/or surfaces of the combustion chambers and piston heads of the engine. The engine was made in an aluminium-based alloy. After said coating, the engine was driven with a fuel for 30 minutes. After said driving of the engine, the excess of catalyst was removed. The catalyst coating had a thickness of less than about 70 nm, with metal particles homogeneously dispersed. On the tube face of the combustion cylinders, substantially no catalyst was present or catalyst with a very small thickness.

(58) The engine of the invention will have the advantages disclosed in the article: Opposed-piston engines: the future of internal combustion engines?, Kalke Jakub et al.

(59) The engine will moreover have the following advantages:

(60) high thermal stability of the catalyst

(61) high pressure stability

(62) high hydrogen stability

(63) working of the engine possible with different cetane number or octane number

(64) high ionic conductivity of the coating

(65) possible ignition control at different compression ratio from 6 up to more than 15, such as 20 or more, for example 22;

(66) possibility to burn at least partly the carbon and the hydrogen from the fuel separately, namely a large portion of the fuel carbon in the volume of the chamber (comprising the plasma zone adjacent to the catalyst coating(s), i.e. in a N.sub.2 enriched environment with respect to air), and a large portion of the fuel hydrogen on or in the catalyst coating(s) (i.e. namely in a O.sub.2 rich environment or in a reduced N.sub.2 environment with respect to air) High oxygen storage capacity, with high uptake and release oxygen rate High hydrogen storage capacity

(67) Possible down sizing of the filter, due to less small particle emissions, as well as down sizing of the three way catalyst exhaust

(68) Possibility to use a filter with large pore size

(69) Possibility to reduce pressure drop in the exhaust, at the level of the filter, as well as at the level of the three way catalyst

(70) quicker activation of the three way catalyst

(71) stable working of the catalyst during time, whereby less catalyst rejuvenation is needed

(72) possible working of the engine with lambda value higher than 1.3, such as higher than 1.4, such as from 1.4 to 1.3, such as from 1.5 to 2.1.

(73) improved post treatment less NOx low HC content in the exhaust gases high steam, superheated steam formation less carbon particles exhaust (especially substantially no small sized carbon particles exhaust, such as substantially no carbon particle with a size of less than Sum) no soot formation in the combustion chamber no soot deposit in the exhaust pipe high water vapour exhaust. Lower fuel consumption Higher global amount of free electrons in the combustion chamber The combustion was a dual stratified combustion with two opposite surfaces provided with a cerium-carbon containing coating. The catalyst coating will reacts differently in function of the oxygen content present within the combustion chamber, thus during the intake and compression phases (oxygen rich atmosphere), and during the combustion and exhaust phases (oxygen poor or depleted atmosphere).

(74) The engine was working with a fuel direct injection system, as well as preferably with a liquid water (as micro droplets) direct injection into the combustion chamber, such system are for example systems like the K-Jetronic fuel range of systems of Bosch GmbH and WI (Water Injection) of Bosch GmbH. Water injection technologies are disclosed in U.S. Pat. Nos. 5,174,247, 6,067,964 and 6,092,514.

(75) The following results were observed: lower fuel consumption, lower NOx emission, lower small carbon particles emission, better, improved working of the engine (less vibrations), better working of the filter and exhaust treatment system, etc.

(76) The engine was an engine with compression ignition. It was observed that it was possible to increase the compression ratio before ignition in a spark ignition engine as well as for compression ignition engine, with respect to currently used ignition compression ratio. Moreover, possible ignition was possible with a spark plug within a large range of compression ratio.

(77) As the pressure drop in the exhaust converter system and filter was reduced with respect to the pressure drop in the exhaust converter system and filter of the current engines, while ensuring a high level of removal of carbon particles and/or conversion of toxic NOx molecules, a better air filling of the combustion chamber was possible with the engine of the invention. Moreover, when the air intake system (inlet canals or intake ports) and the exhaust valve are both in open position, air can more easily flow through the combustion chamber of the engine of the invention, ensuring in this way an oxygen uptake by the catalyst coating, as well as a cooling of the combustion chamber, and even a high scavenging of exhaust gases.

(78) In view of the lower pressure drop in the exhaust converter system, exhaust gases can be better used for driving into rotation of a turbine (for which ever purposes), when required and/or for EGR (exhaust gas recycling) purposes. Due to the low level of carbon particles content, EGR is better performing and the EGR system is not subject to clogging problems

(79) The engine could also be an engine with spark ignition or with other means for controlling the ignition.

(80) The engine can also be provided with Bosch like injectors for injecting water drops or droplets and/or water vapour in the air intake (before and/or after the air butterfly valve in the manifold, and/or directly within the combustion chamber).

(81) The catalyst coating of the invention can thus be considered as being a highly coordinated selective, oxidising and reducing self supported redox catalytic system, whereby selective oxidising and selective reducing can vary or be controlled in function of temperature and photon emission.

(82) The opposite pistons engine can also be of the type not using wobble plates for transmitting the power generated by the fuel combustion and the displacement of the pistons to a driving axis. The opposite pistons engine can also be of the type fairbanks-Morse diesel engine.

(83) FIG. 4 shows in perspective a wobble plate 20 connected by means rods 21 (with spherical head enabling a rotation of the head within a recess of a arm of the wobble plate) to five pistons (2 or 3) moving in distinct cylinders 1, the said wobble plate being located at one end of said cylinders 1. Another wobble plate is connected similarly to the other pistons moving in the cylinders 1. The two wobble plates (also known as swash-plates) are linked the one to the other by a central axis 24 which is driven into rotation by the movement of the wobble plate.

(84) Wobble plates opposite pistons engines are for example of the type: Lamplough axial engine (see douglas-self.com; U.S. Pat. No. 1,765,167); Wishon (U.S. Pat. No. 1,476,275), Sterling axial engine (U.S. Pat. No. 2,080,846), etc.

(85) FIG. 5 shows an incineration plant comprising an at least partly stratified combustion chamber C in the form of a fluidised bed, a flue gas collecting system D for collecting the flue gases exhausted by the combustion of the combustible material in the combustion chamber C, a heat exchanger E, and a flue gases exhaust treatment system F comprising a system F1 for treating flue gases with a dry absorbent (such calcium hydroxide) and a filter system F2 for recovering solid particles still present in the flue gases.

(86) The combustion chamber C comprising at least two successive distinct burning zones C1,C2, a flue gas outlet C3, and an ash outlet system C4. The combustion chamber C is adapted for burning a combustible material in presence of air or oxygen enriched air, whereby said chamber comprises a first burning zone C1 (a fluid bed burning zone) provided with at least one inlet 111 for the combustible material to be burnt (admitted above the fluid bed support 110) and at least one inlet 12 for the admission of air and/or oxygen enriched air below the fluid bed support 110 for keeping the material to be burnt in suspension above the fluid bed support 110. The first burning zone is also provided with an inlet 13 for the admission of water vapour above the fluidised bed, preferably just before flue gases enters the second burning zone C2.

(87) Said first burning zone C1 is extended with a channel system forming the second burning zone C2, said channel system collecting all gases and some solid particles issued from the first burning zone C1, whereby said channel system is provided with a series of guiding catalytic channels 15 extending each between a first end 15A directed towards the first burning zone C1 and a second end 15B directed towards the gas outlet D of the combustion chamber C, said guiding catalytic channels 15 being provided each with a means 15C (located adjacent to the end 15B of the guiding catalytic channel 15), 15D (located in between the ends 15A and 15B, post particularly between the end 15A and the means 15C) for forming at least one restricted passage adjacent to the second end 15B, as well as within (such as at half way) the guiding channels, said restricted passage of a guiding catalytic channel having an open surface which is comprised between 25% and 90% of the open surface of the guiding catalytic channel considered adjacent to the first open end 15A. The restricted passage of a guiding channel formed by the means 15C is for example from 40 to 50% of the open passage of said guiding channel at its end 15A, while the restricted passage of a guiding channel at the level of the means 15D is for example from 51 to 65% of the open passage of said guiding channel at its end 15A.

(88) The channels 15 can be formed by placing elements 15E adjacent the one to the other, so as to define there between channels 15. The elements 15E are advantageously mounted mobile on a support, so as to enable an easy replacement of one element 15E, when required. The elements 15E can be provided with a precursor coating or a catalytic coating at the production plant.

(89) The channels of the catalytic channel system C2 (forming the second burning zone) is provided with a cerium oxide-carbon containing coating, said coating of the channels further comprising at least comprising oxides of the followings elements Pr, Nd, La and at least Y and/or Zr, whereby said cerium oxide-carbon containing coating with the oxides of the followings elements Pr, Nd, La and at least Y and/or Zr, is adapted for controlling the formation of H+ species on the wall of the chamber, while controlling the hydrogen branching reactions by catalysing the use of oxygen atoms from Ce, Pr, Nd, La and at least Y and/or Zr oxides for reacting with hydrogen H.sub.2 for the formation of H.sub.2O on the wall of the chamber, whereby the weight metal content of the metal element selected from Y, Zr and mix thereof expressed as oxide in the total metal weight content of metal elements selected from Ce, Pr, Nd, La, Y and Zr expressed as oxide is at least 10%, advantageously at least 15%, preferably from 16 to 40%, most preferably from 20 to 30%.

(90) The cerium-carbon coating of the guiding catalytic channels 15 forming the second burning zone is adapted for capturing photons emitted by the flame with wavelength from 6500 to 7500 , advantageously for capturing 5 to 25% of the photons with wavelength from 6500 to 7500 emitted by the flame having a temperature higher than 800 C.

(91) Advantageously, the cerium-carbon coating of the guiding catalytic channels is adapted for ensuring a photon amplified spectrum emission radiation at least at a temperature comprised between 500 and 800 C., said spectrum covering advantageously substantially the whole range from about 4000 up to 7500 .

(92) The guiding catalytic channels have each a minimal passage with a open cross section of at least 2.5 cm.sup.2, advantageously at least 5 cm.sup.2, preferably from 5 cm.sup.2 to 20 cm.sup.2.

(93) The guiding catalytic channels are made at least partly in a temperature ceramic like material, advantageously comprising aluminium, the wall of which being provided with a catalytic coating with a thickness from 50 m up to 1 mm, preferably from 100 m to 5000 m.

(94) The second burning zone C2 comprises at least 20 (such as 50 to 200) distinct and parallel guiding catalytic channels 15.

(95) The second burning zone can also be provided with an air admission system 16, as well as a water vapour admission system 17.

(96) The cerium-carbon containing coating comprises at least Y and Zr, advantageously the weight ratio Y/Zr expressed as oxides present in the catalyst coating is comprised between 1:10 and 10:1, preferably between 2:10 and 10:2. It has been observed that the presence of zirconium was beneficial for ensuring a catalytic efficiency on a long period of time, as well as beneficial for ensuring a more constant and less variable catalytic activity.

(97) The cerium-carbon containing coating comprises some aluminium, preferably in its oxide or hydroxide form and/or in the form of aluminosilicate, whereby the aluminium metal content of the catalyst coating with respect to the total metal weight content of the catalyst coating of metal selected from Al, Ce, Pr, Nd, La and at least Y and/or Zr is comprised between 1 and 10%.

(98) The relative weight of the metals selected from Ce, Pr, La, Nd, Y and Zr, expressed respectively as the following oxides CeO.sub.2, Pr.sub.6O.sub.11, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Y.sub.2O.sub.3. and ZrO.sub.2 of the cerium-carbon containing coating of said guiding catalytic channels with respect to total weight of the said metals expressed as oxides are: Ce (as CeO.sub.2): 25 to 50%, preferably from 35 to 45%, Pr (as Pr.sub.6O.sub.11): 2 to 10%, preferably from 2.5 to 6% La (as La.sub.2O.sub.3): 15 to 37%, preferably from 20 to 32% Nd (as Nd.sub.2O.sub.3): 4 to 15%, preferably from 5 to 13% Y (as Y.sub.2O.sub.3): 5 to 15%, preferably from 8 to 12% Zr (as ZrO.sub.2): 5 to 25%, preferably from 10 to 17%

(99) It was observed that substantially all the hydrogen species were reacted with oxygen into water/water vapour in the catalytic guiding channels 15. When leaving the guiding catalytic channels 15, the pressure of the flue gases was a little reduced with respect to the pressure inside of the channels 15. The pressure thereafter increased due to a phase expansion of the steam (dry superheated steam) in the collecting system D, whereby enabling a first heat/energy recovery). Then the steam containing flue gas passes within the condenser/heat exchange E for a second heat/energy recovery, meaning a drop of pressure.

(100) The (wet) flue gases enter then into the heat exchanger E for recovering heat from the flue gases. The heat recovery was quite effective, as large amount of water could be condensed, said water being acid. The temperature of the flue gases was below 100 C., such as from 70 to 90 C. The so collected condensed water was then further treated for neutralising acid components and for removing solid particles (dust, fly ash, etc.), before being naturally treated in lagoons. The flue gases exhausted from the heat exchanger E are then treated with an absorbent, such as a dry absorbent like calcium hydroxide or calcium hydroxide based absorbent, if required.

(101) After said latest treatment substantially all noxious compounds of the flue gases were removed.

(102) It was observed that some catalyst of the second burning zone C2 formed a deposit on the surface of the flue gases collecting system D as well within the outlet of the chamber, whereby ensuring a further catalytic treatment of the flue gases into the collecting system.

(103) It was also observed that the flue gases exhausted from the catalytic guiding channels 15 were equivalent to a superheateddrysteam, said superheated steam being submitted to some expansion (zone 25) in the gases collecting system adjacent to the outlet 15B of the second burning zone (i.e. with the gas outlet of the chamber). Said superheated dry steam expansion and the condenser E ensuring a high velocity outflow of the hot flue gases, whereby enabling to reduce the velocity of the air necessary for ensuring a fluidisation of the combustible material.

(104) If necessary, some extra liquid or gaseous fuel can be admitted within the first burning zone C1 through an injector 121.

(105) For ensuring some rejuvenation of the catalyst of the second burning zone, methane (or possibly some fuel) and water can be injected within the first burning zone, advantageously without the presence of some waste material or other combustible material.

(106) FIG. 6 is an installation similar to that of FIG. 5, except the installation is provided with an injector 22 for injecting particle combustible material and/or liquid fuel and/or gaseous fuel within the first burning zone C1 (said injection being operated substantially without the presence of oxygen/air), and a system 30 for injecting air in the combustion chamber C. Said system is for example a fan 31 conducting air within a tube 32 extending within the combustion chamber, whereby the injector 22 is located within the said tube 32. The inner wall of the tube is provided with a catalytic coating. The channel system C2 is similar to that of FIG. 5. The installation of FIG. 6 can also be provided with a water vapour injector 16.

(107) The catalytic coating of the tube is advantageously of the same type as the catalytic coating within the second burning zone, as well as on the wall of the flue gases collecting system D.

(108) The combustion chamber, especially the second burning zone is provided with a catalyst or a catalyst precursor.

(109) The catalytic guiding channels C2 or the tube 32 are for example a support (alumino silicate, alumina silico phosphate, ceramic, etc.) provided with a catalyst coating or a precursor coating suitable for generating a catalyst coating.

(110) The precursor used was a mix of nano scale particles possibly dispersed in a wax or liquid, the composition of said mix being:

(111) 1. nano carbon primary particles with a size of less than 10 nm (possibly agglomerated into a structure with a size of less than 500 nm. Said nano carbon primary particles are present in the precursor mix at a rate of 10 to 50% by weight, advantageously from 15 to 30% by weight, preferably about 20% by weight. Instead of using carbon nano particles as such, a wax possibly with carbon nano particles can be used. The carbon particles are preferably comprising some particles forming a two-dimensional graphene and/or graphane structure, most particularly a mono layered two dimensional graphene and/or graphane structure.

(112) 2. a mix of metal oxide particles, especially of nanoparticles (particles with a size of less than 200 nm, preferably at least partly less than 50 nm. Said mix of metal particles comprises advantageously with respect to the total mix of said metal oxide particles (as weight %): Ce (as CeO.sub.2): 25 to 50%, preferably from 35 to 45%, Pr (as Pr.sub.6O.sub.11): 2 to 10%, preferably from 2.5 to 6% La (as La.sub.2O.sub.3): 15 to 37%, preferably from 20 to 32% Nd (as Nd.sub.2O.sub.3): 4 to 15%, preferably from 5 to 13% Y (as Y.sub.2O.sub.3): 5 to 15%, preferably from 8 to 12% Zr (as ZrO.sub.2): 5 to 25%, preferably from 10 to 17% Al (as Al.sub.2O.sub.3): 0 to 10%, preferably from 1% to 5% Si (as SiO.sub.2): 0 to 10%, preferably from 0.5 to 5% (Said silicon can be in the form of liquid or soluble tetra ethoxy silane, in a solvent system, such as methanol, ethanol, etc.)
The mix of nano oxide particles is advantageously a mix of nano oxide particles with a weight average size of more than 100 nm and of nano oxide particles with a weight average size of less than 70 nm, the weight ratio nano oxide particle with a weight average size greater than 100 nm/nano particles with a weight average size lower than 70 nm being comprised between 5:1 and 1:5, advantageously between 4:1 and 2:1.

(113) 3. possibly a wax or liquid system, for enabling some adhesion of the particles on the surface to be coated, said wax or liquid being preferably molecules comprising carbon and hydrogen, as well as preferably oxygen atoms.

(114) the weight ratio wax/mix of metal oxide particles is advantageously greater than 2, such as comprised from 2.5 up to 6.

(115) The precursor was used for coating (for example by brushing, blowing, spraying, etc.) wall of the combustion chamber. The combustion chamber is then burning fuel with air for 30 minutes. After said burning step, the excess of catalyst was removed.

(116) The catalyst coating had a thickness of less than about 70 nm, with metal particles homogeneously dispersed.

(117) The combustion chamber will moreover have the following advantages:

(118) high thermal stability of the catalyst

(119) high ionic conductivity of the coating

(120) possibility to burn at least partly the carbon and the hydrogen from the fuel separately, namely a large portion of the fuel carbon in the volume of the chamber (comprising the plasma zone adjacent to the catalyst coating(s), i.e. in a N.sub.2 enriched environment with respect to air), and a large portion of the fuel hydrogen on or in the catalyst coating(s) (i.e. namely in a O.sub.2 rich environment or in a reduced N.sub.2 environment with respect to air) High oxygen storage capacity, with high uptake and release oxygen rate High hydrogen storage capacity

(121) Possible down sizing of the filter or gas cleaning unit, due to less small particle emissions, as well as excellent working of the condenser/cooler.

(122) Possibility to use a filter with large pore size

(123) Possibility to reduce pressure drop in the exhaust, at the level of the filter,

(124) quicker activation of the three way catalyst

(125) stable working of the catalyst during time, whereby less catalyst rejuvenation is needed

(126) possible working of the engine with lambda value higher than 1.3, such as higher than 1.4, such as from 1.4 to 1.3, such as from 1.5 to 2.1.

(127) improved post treatment

(128) less NOx

(129) low HC content in the exhaust gases less carbon particles exhaust (especially substantially no small sized carbon particles exhaust, such as substantially no carbon particle with a size of less than 5 m) no soot formation in the combustion chamber no soot deposit in the exhaust pipe high water vapour exhaust. Higher global amount of free electrons in the combustion chamber.