NL1013478C2 - Fuel processor for producing hydrogen and apparatus suitable for use in such a processor for generating a third and fourth gas stream from a first and second gas stream. - Google Patents

Description

Title: Fuel processor for producing hydrogen and apparatus suitable for use in such a processor for generating a third and fourth gas stream from a first and second gas stream.

The invention relates to a fuel processor for producing a gas stream comprising hydrogen by catalytic combustion of a mixture comprising at least one gaseous hydrocarbon compound, water vapor and oxygen, the fuel processor comprising a gas flow path through which the mixture is passed and CPO catalyst included in the gas flow path, to which the mixture is fed for catalytic combustion. (This represents 10 CPO for Catalytic Partional Oxidation).

The invention also relates to a device for generating a third and fourth gas stream from a first and second gas stream.

A fuel processor of the type described in the preamble 15 is known per se. The hydrogen that is generated is often used to be supplied to a fuel cell that burns the hydrogen to generate electrical energy and / or heat. It is important here that the hydrogen generated by the fuel processor comprises as little carbon monoxide as possible, because this is detrimental to the proper functioning of the fuel cell. One of the objects of the invention is to provide a fuel processor that generates a gas stream with hydrogen which comprises less carbon monoxide than the known fuel processor. The fuel processor of the invention is accordingly characterized in that the gas flow path downstream of the CPO catalyst includes a plurality of series-connected HT shifts which, in use, flow through the mixture leaving the CPO catalyst, respectively. The inclusion of a plurality of series-connected HT shifts opens the possibility of controlling the temperature of the 101 3478 2 mixture flowing through the HT shifts per HT shift. This allows the stated amount of CO to be minimized. HT-shift stands for High-temperature-shift catalyst. In particular, it holds that in the gas flow path heat exchangers located between the CPO catalyst and the HT-shift closest to the downstream of the CPO catalyst and between the HT-shifts respectively, exchange heat between, on the one hand, the mixture supplied to the CPO catalyst. catalyst is supplied and, on the other hand, the mixture which flows downstream of the CPO catalyst through the series-connected HT-Shifts. This ensures that the temperature of the mixture leaving an HT shift is higher than the temperature of the mixture flowing into an HT shift situated downstream of the latter HT shifts. As the temperature decreases downstream per HT shift, this results in the reaction equilibrium being shifted such that the amount of carbon monoxide in the mixture 20 decreases accordingly.

According to a practical elaboration, each HT shift is provided with two opposite sides which respectively form an input and an output of the HT shift, the HT shifts in a direction coinciding with the normal of the said sides of the HT shifts are arranged with respect to each other, with an output of a first HT shift opposite an input of a second HT shift and the second HT shift being contained in a box-shaped chamber with a bottom and upright sidewalls, in which the bottom lies between the entrance of the second HT-shift and the exit of the first HT-shift and the gas flow path from the first HT-shift to the second HT-shift extends along an outer side of the bottom of the box-shaped chamber, between the heat exchanger and an outside of the upright side wall of the 101 3478 3 box-shaped chamber, between the second HT shift and an inside of the upright side wall of the box-shaped chamber to a space located between the inside of the bottom of the box-shaped chamber and the side of the second HT shift comprising the entrance. In this way, the fuel processor can be made very compact. In particular, each HT shift is contained in a box-shaped chamber. This measure also ensures that the fuel processor can be made very compact. This is especially true when each HT shift is tubular in shape with two opposite open ends which form the entrance and exit of the HT shift, respectively, with axial axes of the HT shifts coinciding at least substantially with an axial axis of the tubular inner wall of the heat exchanger.

In that case, it preferably holds that the heat exchanger is further provided with a tubular insulating outer wall, which has a heat insulating function.

In order to further improve the efficiency and to reduce the amount of carbon monoxide, it then holds in particular that the gas flow path further includes an LT shift located downstream of the HT shifts, the fuel processor further comprising an inlet for the use, adding water to the mixture fed to the LT shift to cool the mixture. LT-shift stands for Low-temperature-shift catalyst. The processor can further be provided with means for adding the water in the form of steam. However, it is also possible for the inlet to include misting means for adding the misting water. This has a very favorable effect on the return.

According to a highly advanced embodiment of the fuel processor, the LT shift comprises a tubular insulating outer wall and a tubular insulating inner wall arranged concentrically with each other, in use, the mixture separating the tubular insulating material. inner wall and the tubular insulation-outer wall formed space flows through and wherein the HT shifts and the CPO catalyst are accommodated in a space enclosed by the tubular insulation inner wall.

This makes the fuel processor very compact. The heat flows in that case are in particular directed in a radial direction from the inside to the outside, while the flow of the mixture is directed at least substantially in the axial direction. In particular, it applies that the tubular insulating outer wall of the heat exchanger coincides with the tubular insulating inner wall of the LT shift. In order to further reduce the amount of CO, it preferably holds that the processor is furthermore provided with a PrOx situated downstream of the LT shift in the gas flow range, as well as an inlet for adding oxygen to the mixture containing the LT shift. has left and flows to the PrOx. Here PrOx stands for 'preferential oxidation' = selective CO oxidation-20 catalyst.

According to a very advanced embodiment, the processor furthermore comprises a vessel which is filled with water and / or is flowed through with water, the gaseous hydrocarbon compound and oxygen being further supplied to the vessel to pass through and / or along the water. are fed to generate said mixture to be supplied to the CPO catalyst and water temperature control means to adjust the concentration of the water vapor in the mixture to be supplied to the CPO catalyst. Because water is added to the mixture, more hydrogen is formed per mole of the gaseous hydrocarbon compound in the mixture than if the mixture would comprise only gaseous hydrocarbon and oxygen (air). 35 To further minimize the amount of CO

furthermore, the processor may further include a heat exchanger for exchanging heat between the mixture that has flowed through the PrOx and the water contained in the vessel such that the temperature of the mixture containing the hydrogen gas stream forms, 5 drops.

According to the preferred embodiment, it holds that in the gas flow path between the LT shifts and the PrOx, a further heat exchanger is included for further cooling of the mixture.

The invention also relates to a fuel processor of the type described in the preamble, characterized in that the processor further comprises a vessel filled with water, the gaseous hydrocarbon compound and oxygen being further supplied to the vessel in order to passed through and / or along the water to generate said mixture and means for controlling the temperature of the water to adjust the concentration of the water vapor in the mixture.

According to the invention, for the device for generating the third and fourth gas stream from a first and second gas stream, the third gas stream comprises a mixture of the first and second gas stream, wherein the device is provided with a chamber enclosing a space in which a fan is included in which the chamber is provided with a first and second inflow opening for, in use, supplying the first and second gas stream to the first and second inflow opening, respectively, and a first and second outflow opening, wherein, in use, the first and second second gas stream is drawn in through the fan and separated in the chamber and fed to the first and second outflow openings respectively, the first outflow opening opening directly into a first outlet and the second outflow opening opening out into the first outlet and a second 101 3478 6 outlet with in the first and / or second outlet A controllable valve is included to adjust the ratio of the amount of gas from the first and second gas streams to the third gas stream from the first outlet, with the fourth outlet flowing through the second outlet comprising a portion of the second gas stream.

The advantage of such a device is that two gas flows can be pressurized with the aid of one fan. In addition, the size of the two 10 gas flows is controlled (modulated) in the same ratio by a corresponding control (modulation) of the fan speed. In particular, it holds that the chamber comprises a cylindrical outer wall enclosing a cylindrical space in which the fan is designed as a wheel, a rotary axis of which coincides with an axial axis of the chamber, the wheel being provided with blades on either side near its peripheral edge. and wherein the first gas flow extends on a first side of the wheel where the blades are located and the second gas flow extends on a second side of the wheel where the blades are located.

According to a further elaboration it holds that the first and second inflow opening are arranged offset in the axial direction of the chamber in the cylindrical outer wall of the chamber, the first inflow opening and the first outflow opening are arranged at least substantially in the same plane that is perpendicular is directed to the axial axis of the chamber and wherein the second inflow opening and the second outflow opening 30 are arranged substantially in the same plane that is perpendicular to the axial axis of the chamber.

According to a further elaboration, the chamber is provided with two opposite side walls which are oriented perpendicular to the axial axis of the chamber, the first side wall comprising a first circular groove extending around the axial axis, in which 101 3478 7 the first inflow and outflow opening is received and wherein the second side wall comprises a second circular groove extending around the axial axis in which the second inflow and outflow opening is received and wherein the blades of the wheel extend along the first and second groove, respectively.

Such a device can advantageously be used in the above-described fuel processor. Here, it holds that the first gas stream consists of a mixture of air and a gaseous hydrocarbon compound and the second gas stream consists of air, the third gas stream consists of a mixture of the first and second gas stream and the fourth gas stream consists of a fraction of the second gas stream and wherein the third gas stream is fed to the gas stream traetet and the fourth gas stream is added to the mixture which is fed to the PrOx.

The invention will be further elucidated with reference to the drawing. Herein shows: FIG. 1 a possible embodiment of a. fuel processor according to the invention; Fig. 2 shows the temperature trend along the gas flow trace through the CPO catalyst, the HT shifts, the LT shift and the PrOx of the fuel processor according to Fig. 1; Fig. 3 shows the temperature trend along the line Q of Fig. 1; Fig. 4 is a part of the device according to Fig. 1; Fig. 5A shows a first cross-section of a device 30 according to the invention, which can advantageously form part of the fuel processor according to Fig. 1; fig ,. 5B is a second cross section of the device of FIG. 5A; and FIG. 6 is an alternative embodiment of the vessel 6 of FIG. 1; 101 347 8 8

In Fig. 1, reference numeral 1 denotes a fuel processor for producing a gas stream comprising hydrogen. The fuel processor is of a type that generates hydrogen by catalytic treatment of a mixture comprising at least one gaseous hydrocarbon compound, water vapor and oxygen. The mixture is then passed along a gas flow stage for the combustion of the relevant mixture. To obtain the mixture, the device 10 is provided with a vessel 2 filled with water (H 2 O). The vessel 2 is provided with an inlet 4 to which the gaseous hydrocarbon, in this example CH 4, and oxygen, in this example air, is supplied. supplied. The gaseous hydrocarbon and oxygen are thus injected into the bottom of the vessel 2 and will bubble up through the water 6 contained in the vessel. The gaseous hydrocarbon and oxygen bubbling up into the water 6 form above the water surface in the vessel 2 a mixture 8 which also includes water vapor. The fuel processor is provided with 20 means 10 for controlling the temperature of the water 6. The temperature of the water 6 also determines the temperature of the mixture 8. The temperature of the mixture 8 directly determines the amount of water vapor contained in the mixture 8 is recording. The higher the temperature, the higher the degree of saturation of the mixture with water. The mixture 8 thus formed is passed from an outlet 9 of the vessel 2 along a gas flow stage for the catalytic combustion. For the catalytic combustion 30, this gas flow trace contains, inter alia, a CPO catalyst 11 known per se. This CPO catalyst consists of a catalyst as is also used for cars.

The gas flow trajectory further comprises a plurality of series-connected 35 HT shifts 16.1-16.3 downstream of the CPO catalyst. This example concerns three series-connected HT shifts. These HT shifts are flowed through the mixture leaving the CPO catalyst in use.

The mixture 8 which is fed to the CPO catalyst causes the following 5 reactions in the CPO catalyst:

Vk CH4 +% 02 - »C02 +% H20 + Q (400 -> 900 ° C) (1)% CH4 + ^ H20 O ^ CO + 3/2 H2 - Q (900 -> 700 ° C) (2) K CH4 + M C02 o% CO +% H2 - Q (3) 10 CH4 +% 02 - »CO + 2 Ha (4)

This shows that in addition to hydrogen (H2), carbon monoxide (CO) is also formed. Q indicates that heat is released. The gas stream, which besides hydrogen also comprises a large amount of carbon monoxide, is not suitable for being fed to a fuel cell for generating electric energy and / or heat. The carbon monoxide causes the fuel cell to function less well. An advantage of the additional water addition is that reaction (2): 20 CH4 + H20 ** CO + 3H2 (900 - »700 ° C) instead of (900 -» 800 ° C) increases relatively and that the amount of carbon monoxide (CO ) relative to the amount of hydrogen (H2) generated. Therefore, an equivalent of partial CO shift 25 already occurs. The amount of hydrogen thus generated can be controlled by controlling the amount of water contained in the mixture 8. With this the reaction according to formula 4 will occur to a greater or lesser extent.

In this example, the vessel is provided with a water outlet 12 schematically shown in Fig. 1 to supply the water 6 of the vessel to an electric heating element 10. The heated water thus obtained is fed back to the vessel via a conduit 14. The temperature of the water 6 in the vessel 2 can therefore be controlled by means of the heating element 10.

1013478 10

In the gas flow path downstream of the CPO catalyst 11, a plurality of series-connected HT shifts 16.1-16.3 are included. This example concerns three series-connected HT shifts known per se. These HT shifts also consist of a catalyst known per se, such as of the type also used for cars. The mixture leaving the CPO catalyst comprises, as discussed, an amount of carbon monoxide (see Formula 2 and Formula 3). When this mixture is fed to the first HT shift 16.1 10, the following reaction occurs in the HT shift 16.1: CO + H20 O CO2 + H2 (5) 15 The advantage of the HT shift is therefore that the amount of CO in the mixture is reduced, while as a by-product the CO2 which is harmless to a fuel cell is generated. In order to ensure that the reaction equilibrium of the reaction according to formula 4 is 20 such that the amount of CO is very low, the gas flow path is respectively between the CPO catalyst 11 and a nearest downstream of the CPO catalyst. located HT shift 16.1 and between the HT shift mutually (16.1-16.2; 16.2-16.3) heat exchangers included, which exchange heat between, on the one hand, the mixture which is supplied to the CPO catalyst 11 and, on the other hand, the mixture which is downstream of the CPO catalyst flows through the series-connected HT-shift. The heat exchangers in this example comprise a tubular inner wall 18 which encloses a space 20 in which the HT shifts are accommodated. Each HT shift 16.1-16.3 has two opposite sides which form their input 22 and an output 24 of the HT shift, respectively. The HT shifts are arranged in a direction 26 coinciding with the normal 35 of said sides of the input and output 22, 24. Here, an output 101 3478 11 24 of a first HT shift 16.1 is opposite an input 22 of a second HT shift 16.2. Furthermore, it holds that the second HT shift 16.2 is accommodated in a box-shaped chamber 28 with a bottom 30 and upright side walls 32. The bottom 30 is between the entrance 22 of the second HT shift 16.2 and the exit 24 of the first HT. shift 16.1 included. This entails that the gas flow path from the first HT shift 16.1 to the second HT shift 16.2 extends along an outer side of the bottom 30 of the box-shaped chamber 28, respectively, between the heat exchanger, ie the tubular inner wall 18 and an outer side. from the upright side wall 32 of the box-shaped chamber 28, between the HT-shift 16.2 and an inner side of the upright side wall 30 of the box-shaped chamber 28, to one between the inner side of the bottom 30 of the box-shaped chamber 28 and the side of the second HT shift 16.2 comprising the entrance 22, located space 34. The first HT shift 16.1 and the third HT shift 16.3 are also provided with a box-shaped chamber 28. The gas flow path from the CPO catalyst to the entrance of the The first HT shift 16.1 and the gas flow path from the output of the second HT shift 16.2 to the input of the third HT shift 16.3 is therefore entirely analogous to the gas flow path from the output of the first H T-shift 16.1 to the entrance of the second HT-shift 16.2 has been discussed. In this example, each HT shift is tubular in shape with two opposite open ends 22, 24, which respectively form the entrance and exit of the respective HT shift. Axial axes of the HT shifts (arrow 26 in the drawing) coincide at least substantially with an axial axis of the tubular inner wall 18 of the said heat exchanger. The heat exchanger in question is furthermore provided with a tubular insulating outer wall 36, which encloses the tubular inner wall 28 entirely but with an intermediate space.

The operation of the device described up to this point is as follows.

101 347 8 12

The mixture 8 entering the vessel 2 will have a temperature of about 70 to 80 °. The mixture 8 is led to the CPO catalyst via a space located between the inner wall 18 of the heat exchanger and the outer wall 36 of the heat exchanger. Fig. 2 shows the temperature course of the mixture flowing through the CPO catalyst and HT shift 16.1, 16.2 and 16.3, respectively. The course of the gas flow path 2 is plotted along the horizontal axis by the CPO catalyst and the HT shifts 10. Before the mixture flows into the CPO catalyst, the mixture will have a temperature of about 350-500 ° C (fig. 2: 400 ° C). The reactions according to formulas 1, 2, 3 and 4 occur in the CPO catalyst. See curve A of Figure 2. The mixture leaving the CPO catalyst will then have a temperature of about 685 ° C. The mixture then flows from the CPO catalyst along the inner side of the inner wall 18 of the heat exchanger and results in it heating the mixture flowing on the outside of the inner wall 18 from the vessel. The mixture flowing from the CPO catalyst to the entrance of the first HT shift 16.1 will accordingly be cooled to, for example, 575 ° C (see curve B). Thus, at the entrance of the first HT shift, the mixture will have a temperature less than the temperature of the mixture at the exit of the CPO catalyst. When the mixture flows through the first HT shift, its temperature will increase, as indicated by curve C in fig. 2. The temperature hereby rises again to 580 ° C. In the range from the HT shift 16.1 to the HT shift 30 16.2, the mixture will flow past the heat exchanger and cool again to, for example, 450 ° C. (Curve D). If the fuel processor were to have only one HT shift with the combined lengths of 16.1, 16.2 and 16.3, the temperature of the mixture in the HT shift would further rise as indicated by the dotted line in Fig. 2.

At the end of the HT shift range indicated by point Px in 101 3478 13 Fig. 2, this would mean that the amount of CO in the mixture would be much more than 3%, for example. However, the processor according to the invention makes use of a plurality of HT shifts 5, for example, the mixture leaving the first HT shift 16.1 is cooled by flowing along the inner side of the tubular inner wall 18 of the heat exchanger, resulting in that the mixture fed to the inlet 22 of the second HT shift 16.2 has a reduced temperature of, for example, 450 ° C. When the mixture then flows through the second HT shift, the temperature of the mixture will slowly rise again, as indicated by curve 16.2 in Fig. 3. Entirely analogously, the mixture leaving the second HT shifts 16.2 15 will again be cooled by flowing along the inner wall 18 of the heat exchanger, as a result of which the mixture fed to the third HT shift 16.3 has a temperature of, for example, 370 ° C. The mixture leaving the third HT shift 16.3 then has a lower temperature (for example 355 ° C), as indicated by the point P2 in Fig. 2. As a result, of the mixture exiting the third HT shift 16.3, the reaction equilibrium of the reaction of formula 4 is displaced such that the amount of CO is much less than would have been the case at point Px of FIG. 2.

However, the processor includes still further discussed measures to further displace the reaction equilibrium such that even less CO is present in the mixture. For this purpose, the fuel processor is further provided with an LT shift 38 located downstream of the HT shifts 16.1-16.3. Furthermore, the fuel processor is further provided with an inlet 40 for, in use, adding water to the mixture which is added to the LT shift is applied to cool the mixture. For example, the mixture leaving the HT shift 16.3 has a temperature of 355 ° C. By adding water vapor to the inlet 10134 78 14 via the inlet 40, it will be cooled. Thereby the following favorable shift of the thermodynamic equilibrium position occurs: ^ - 5 CO + H20 - * C02 + H2 (6)

The processor may further include means for adding the water through the inlet 40 in the form of steam. These means can for instance consist of a steam generator 42 comprising an electric heating unit, a hydrogen burner, or a natural gas burner and a heat exchanger. It is also possible that the inlet 40 comprises atomizing means for adding the water in the atomized state. The water in the atomized state can then have a temperature corresponding to room temperature. It is then not necessary to heat water to steam. Instead, after atomization without heating, the water can thus be supplied to the mixture without supplying additional energy for cooling the mixture. The cooling of the mixture to 180 ° C in this way is indicated by curve E in Fig. 2. The cooled mixture is thus fed to the LT shift 38. The LT shift comprises a catalyst material known per se. In this example, the LT shift comprises a tubular (heat) insulation outer wall 44, and a tubular inner wall 36 which, in this example, coincides with the tubular (heat) insulation outer wall of the heat exchanger. The tubular outer wall and the tubular inner wall of the LT shift are arranged concentrically with each other, in use the mixture flowing between the tubular inner wall 36 and the tubular outer wall 44 flowing. Outside the outer wall 44 there is cooling water 45 with a temperature of, for example, 20-100 ° C. By heating, this cooling water will be partly converted into steam 47 which is supplied via a pipe 49 to the mixture 8 which flows through the outlet 9 1013478 15. Also in LT shifts the reaction equilibrium according to formula 6 will be shifted such that the amount of carbon monoxide decreases further. Because the temperature of the mixture that flows through the LT shift 5 has already decreased sharply, it has been ensured that the LT shift has a larger volume than the HT shifts. This means that the residence time of the mixture in the LT shift increases. The residence time is so long that the relatively slow-running reaction according to Fig. 3 nevertheless results in the amount of carbon monoxide decreasing further. The temperature rise of the mixture along the gas flow path flowing through the LT shift is indicated by curve F in Fig. 2. For example, when the mixture leaves the LT shift, the amount of CO will be less than 1000 ppm.

In Fig. 1, the point at which the mixture enters the LT shift is indicated by P2 and the point at which the mixture leaves the LT shift is indicated by P3.

The processor further comprises a downstream of the LT shift in the gas flow path located per se known PrOx 46 as well as an inlet 48 for adding oxygen to the mixture that has exited the LT shift and flows to the PrOx.

The following reactions occur in the PrOx: 25 H2 + 2CO + 02 - »2C02 + H2 (7)

The amount of CO will therefore decrease further in the PrOx. In the PrOx, the temperature rises from about 100 to 110 ° C as shown in curve 2 in Fig. 2. Subsequently, the mixture leaves the PrOx via line 50. In line 50, therefore, the end product flows from the fuel processor, which end product consists of a gas stream comprising hydrogen, nitrogen carbon dioxide and water vapor.

Starting from the CPO catalyst, a radially decreasing temperature gradient from the inside to the outside will be present, as shown in Fig. 3.

The device can furthermore be provided with a fuel cell to which the hydrogen can be supplied via line 50. In the fuel cell 52, the hydrogen is burned to generate electrical energy and / or heat. It is also possible that a portion of the hydrogen in line 50 is fed to line 42 'through line 50' when it is configured as a hydrogen burner to provide steam supplied to inlet 40. It is also possible to supply electrical energy E from the fuel cell 52 to the means 42 when they comprise an electric heating unit for generating steam. It is also possible that the electric heating elements 10 for heating the water 6 of the vessel 2 are fed by electric energy from the fuel cell 52. Of course, the electric heating elements 10 can also be replaced by a hydrogen burner 10 for heating the water. water 6, which hydrogen burner 10 is fed with part of the hydrogen flowing through line 50. All this is also shown schematically in Fig. 1. The processor may furthermore be provided with a heat exchanger 54 for exchanging heat between the mixture which has flowed through the PrOx 46 and the water 6 contained in the vessel, so that the temperature of the mixture drops.

When the fuel processor is provided with the fuel cell 52, it is also possible that the heated water, which is formed in the fuel cell 52 when hydrogen is burned, is supplied to the inlet 40 in the form of steam. In that case, the fuel cell 52 is also part of the means for forming steam.

As shown in Fig. 4, the device can furthermore be provided with a heat exchanger 53 included between the LTS and the PrOx in the gas flow path 101 34 7 8 17 with a water inlet 53A of, for example, 20-70 ° C and an outlet 53B for water of, for example, 100 ° C. The mixture then cools in the heat exchanger, for example from 200 ° C to 110 ° C. (See curve G of fig. 2). The outlet 53B can for instance communicate with the inlet 40. The heat exchanger 53 can then replace the steam generator 42. In the PrOx 46, the temperature of the mixture rises as shown in curve H of Fig. 2. Downstream of the PrOx 10 46, the temperature decreases due to the water layer 51 as shown in curve I of Fig. 2.

Figures 5A and 5B show an apparatus for generating at least a third and fourth gas stream from a first and second gas stream, which third gas stream comprises a mixture of the first and second gas stream. More specifically, the device includes a chamber 60 enclosing a space 62 in which a fan 64 is incorporated. The chamber is provided with a first and second inflow opening 66, 68, for supplying the first and second gas stream to the first and second inflow opening 66, 68 in use, respectively. The first and second gas stream are drawn in by the fan. The chamber further comprises a first and second outflow opening 70, 72, wherein, in use, the first and second gas stream 25 is drawn in by the fan and fed into the chamber separated from each other, respectively, to the first and second outflow opening.

The first outflow opening opens into a first outlet 76 with a relatively large cross-section. The second outflow opening 72 opens via a split into the first outlet 76 and the second outlet 78 with a relatively small cross section relative to the cross section of the first outlet 76. This implies that the flow resistance of the first outlet 76 is smaller than the flow resistance of the second outlet 78. In the first and / or second outlet a controllable valve 79 7 0 7 34 78 18 is further included for adjusting the ratio of the amount of gas originating from the first and second gas flow in the third gas stream flowing from the first outlet 76. The fourth gas stream, which comprises a part of the second gas stream, flows from the second outlet 78.

Thus, the third gas stream in the outlet 76 comprises a combination of the first gas stream and the second gas stream supplied to the first and second inflow openings 66, 68, respectively. The fourth gas stream from the outlet 78 comprises only a portion of the second gas stream supplied to the second inflow opening 68. This is caused by the above mentioned difference in flow resistances. When the speed of the fan 64 is varied, the magnitude of the third and fourth gas stream will vary accordingly, the ratio between the magnitude of the fourth gas stream and the third gas stream remaining constant.

In this example, it holds that the chamber comprises a cylindrical outer wall enclosing a cylindrical space 20. The fan 64 is designed as a wheel, a rotary axis 74 of which coincides with the axial axis of the chamber. The wheel is provided with vanes 77 near its peripheral edge 73 on either side 75A, 75B. The first gas flow extends on a first side 75A of the wheel and the second gas flow extends on a second side 75B of the wheel. The first and second inflow openings 66, 68 are offset in the axial direction of the chamber in the cylindrical outer wall. The first inflow opening and the first outflow opening are arranged at least substantially in the same plane that is perpendicular to the axial axis of the chamber. It also holds that the second inflow opening and the second outflow opening are oriented at least substantially in the same plane, which is perpendicular to the axial axis 74 of the chamber.

101 3478 19

In particular, it holds that the first outlet 76 of the device of FIGS. 5A and 5B is connected to the inlet 4 of the vessel 2 of FIG. 1. The second outlet 78 can be connected to the inlet 48 as shown in FIG. 1. In that case, the device according to Figs. 5A and 5B is further provided with a gas block 82 known per se with an air inlet 84 and a gas inlet 86 for supplying a mixture of CH4 and air to the inflow opening 66 via a line 87. Furthermore, air is supplied to the second inflow opening 68 via an air inlet 88. Using the valve 79, a desired ratio between the amount of air and CH4 supplied to the inlet 4 can then be set. Furthermore, by varying the speed of the fan 64, the mixture 15 supplied to the inlet 4 and the air supplied to the inlet 48 can be varied and modulated to the same extent. By varying the speed, a constant energy flow in the processor can thus be controlled.

In other words, in use, in order to modulate the third and fourth gas stream equally, these are the gas streams supplied to the inlet 4 and the inlet 48, respectively, the rotation speed of the fan is modulated.

Furthermore, the chamber is provided with two opposing side walls oriented perpendicular to the axial axis of the chamber, the first side wall 90A comprising a first circular groove 92A extending about the axial axis, wherein the first recesses and outflow opening are included, and wherein the second side wall 90B comprises a second circular groove 92B extending around the axial axis, in which the second inflow and outflow opening are received. The blades 77 of the wheel extend along the first and second grooves, respectively.

The invention is by no means limited to the embodiments outlined above. The vessel 6 as shown in 101 3478 20 fig. 1 can for instance be replaced by a device as shown in fig. 6. Here the inlet 4 shown corresponds to an outlet 9 with the inlet 4 and outlet 9 of fig. 1. The alternative device 5 is provided with a vessel 6 'in which a layer 96 of material in the form of, for example, marbles, salzur, etc. is arranged. The inlet 4 opens below the layer 96. The outlet 9 is located above the layer 96. Above the layer 96 There is also a spray head 98 via which water is deposited with the aid of a pump 100 from a vessel 102 on the top of the layer 96. This water flows through the layer in the material 96 to the bottom 104 of the vessel 6 '. The vessel 6 'is in a position just above the bottom 104 by means of a pipe 108 in fluid communication with the vessel 102. The vessel 102 is further provided with means for heating the water contained in the vessel. These means can consist of electric heating means, a burner, water from the aforementioned fuel cell and / or from one of the aforementioned heat exchangers. With the aid of the pump 100, the water is pumped round from the bottom 104 via the pipe 108 to the vessel 102 and from the vessel 102 to the spray head 98, after which the water flows through the inert material 96 to the bottom 104. At the inlet 4 again the gaseous hydrocarbon, in this example CH4 and oxygen. This gas flows through the inert material 96 to the outlet 9. When the gas flows through the inert material 96, it will flow past said water and thus be saturated with water vapor. The temperature of the water which can be supplied to the inert material 96 via the spray head 98 is variable in this example and can for instance be around 70 ° C. Depending on the water temperature of the water supplied to the nozzle, the mixture is saturated to a greater or lesser degree with water vapor. The water temperature is therefore a variable by means of which the amount of water vapor in the mixture 8 can be controlled. Other variants of the fuel processor according to Fig. 1 are also conceivable. For example, it is possible to use more than three HT shifts. Different temperatures at the inputs and outputs of the HT shifts can also be used than those mentioned in the aforementioned examples. Steam generated with the aid of the fuel processor 52 can for instance be supplied to the inlet 40 via a line 106. Electric energy generated by means of the fuel processor 52 can also be supplied via the lines 108 and / or 110 to the steam generator 42 and / or the heating element 10. All known catalysts can be used for the CPO catalyst, HT-shift, PrOx and LT-shift. The device 6 can be replaced by any system known per se for introducing water vapor.

The fuel processor according to the invention is ideally suited for use in micro-cogeneration units in the domestic environment. This sets special conditions. The processor must be transportable as a whole, from the factory to the place of use, and must not contain any flammable or explosive substances during transport. After placement on the site of use, the cogeneration installation, and therefore also the processor, must be operational in approximately one hour. In case of maintenance or malfunctions, in which air enters the processor, no explosion or flammable situations may arise. In addition, the processor must be as compact as possible.

Said conditions make strict demands on the catalysts in the processor. The catalysts must not be pyrophoric, that is to say, upon the entry of air, as a result of oxidation of the catalyst, no temperature rise must occur such that the catalyst or the possible combustible content of the processor ignites. The catalysts must also be of such chemical composition that any necessary activation can take place in about 1 hour and with process gas.

The catalytic activity must be so high that an almost complete conversion of, successively, methane and carbon monoxide is achieved at high space throughput 5 (Nm3 process gas / m3 catalyst / hour), and thus with small amounts of catalyst.

The CPO and PrOx catalysts can, for example, consist of precious metals, on a support material which is coated on a ceramic monolith. These types of catalysts have been described in the open literature. Suitable active metal includes platinum. Said catalysts convert methane or carbon monoxide 15 almost completely at throughput rates up to at least 2 0.000 Nm3 / m3 / h.

The shift catalysts are characterized by low volume, rapid activation in product gas and non-pyrophoric character.

20 HTS catalysts that can be used, for example 1. Platinum-based catalysts Platinum coated on a γ-Al2 O3 support. Pt content based on the platinum plus carrier weight: 0.1-20 wt.%, Preferably 1-10 wt.%.

Other metals, such as Ru and Rh are also useful (Ru as a shift and methanation catalyst has been described in the open literature).

Alternative carriers include silica-alumina, zirconia. The supported catalyst is coated on a ceramic monolith. Loading of the coating: 50-400 g per liter of monolith, preferably 35 50-300 g / l. The channel density of the monolith: 1013478 23 30-1200 cpsi (= cells per inch2), preferably 100-800 cpsi, most preferably 100-600 cpsi.

Platinum has no activation time and is not pyrophoric. The CO-shift activity is high, so little catalyst material is needed. The disadvantage is that Pt converts part of the CO in the process gas with H2 to CH4 (efficiency loss, power reduction of the fuel cell). The degree of methanation is a question of the kinetics of the methanation compared to that of the CO shift.

10 As the temperature increases, methanation increases relatively compared to the CO shift. For example, the problem can be solved by using 2 HTS monoliths instead of 3. The monolith directly behind the CPO catalyst has the highest temperature and produces the largest amount. This is replaced by a dummy monolith (= uncoated monolith), or disappears entirely from the processor (compact version). The remaining monoliths are located in the cooler zone of the heat exchanger / shift construction. In this way we keep the temperatures below 450 ° C, preferably below 400 ° C. Despite the reduced residence time of the gas, Pt monoliths are still sufficiently active for the desired CO conversion (50-60%). Example in the table.

1013478 24

Configuration Maximum CO loss Loss of temperature in the by H2 production

Pt monoliths methanation (efficiency) (° C) (%) by methanation ____ (%) _ 3 Pt monoliths 550 (3.5 kW 32 12 __ power) ___ (1 dummy), 425 (7 kW) 11 4 2 Pt monoliths ____ (1 dummy), 350 (3.5 kW) 7 3 2 Pt monoliths ____

In summary, the benefits of platinum (fast start-up, no activation procedure, non-pyrophoric, safe, high activity) can therefore be reaped without unacceptable efficiency losses.

2. HTS catalysts based on Fe2O3 / Cr2O3 10 For example, standard commercial ones

Fe203 / Cr203 high temperature shift catalysts are used. The typical composition is 57-59 wt% Fe, metal base, 5-7 wt% Cr, metal base, and about 1 wt% Cu, metal base, as promoter. The catalysts are coated on ceramic monoliths using known techniques. The loading and monolith characteristics are the same as for the Pt monoliths.

The activation of the monoliths takes place in process gas and is completed within 1 hour. Upon activation, Fe2 O3 is reduced to Fe304. Fe304 is slightly pyrophoric. The pellet catalyst can generate so much heat on contact with the air that it can create a fire hazard. By applying the catalyst to a monolith, a thin layer of catalyst becomes open channel 101 3478

structure obtained. Excess Fe304, such as in the core of pellets, which after all is not catalytically active due to diffusion inhibition, is no longer present in the monolith and cannot cause heat problems during oxidation in the air. Due to the open structure of the monolith, oxidation heat quickly becomes. drained. The result is that upon exposure of a reduced monolith to the air, the gas temperature in the channels rises by only 35 ° C. Fe / Cr based monoliths are less active than those based on Pt. 10 3 monoliths are required and maximum temperatures from 550 to 600 ° C

for sufficient conversion. This is not a problem because Fe / Cr catalysts do not have any methanation activity. In other words, with Fe / Cr, the efficiency loss is 0%.

The standard commercial LTS catalyst is CuO met

ZnO (coprecipitation). For example, it is located in the processor as a packed bed of catalyst pellets with a total volume of no less than 20 liters.

The active form in the shift is Cu metal. CuO can very easily be activated in process gas by reduction. However, the heat development is great in this case, so that the catalyst could become too hot and sinter on the first start-up.

In the first place, the aim can be to reduce the amount of copper. This gives less dangerous heat development during reduction and oxidation. However, the activity, i.e. the CO conversion per unit volume of catalyst, should not be affected.

Less copper while retaining activity can be done by finely distributing the metal on a support, such as alumina or silica. Typical loadings are 5-30 wt% Cu, preferably 10-20 wt%. The copper is applied by methods known in the art, such as impregnation of a Cu precursor, drying and calcination.

The disadvantage is that, unlike 101 3478 26 bulk CuO, which is finely divided and sinter-resistant on a support, is difficult to reduce / activate at process temperatures of approx. 200 ° C. This can be solved, for example, by adding 0.1 to 1% by weight of a metal, for example Pt, which absorbs H 2 in the process gas and converts to highly active hydrogen atoms for reduction, which reduce CuO at reduced temperatures. The amount of platinum and the process temperature are such that no efficiency losses due to methanation occur.

An additional increase in activity per 10 volume unit of catalyst is achieved by increasing the steam / carbon ratio in the catalyst particles over that in the process gas. This can be done by adding water-absorbing materials. Suitable are zeolites (molecular sieves) such as A4, A5, 13X, which can absorb about 10 wt.% H 2 O at the process temperature of 200 ° C.

Various forms are conceivable.

- Mixing a ground commercial CuO / ZnO catalyst, or rather a Pt promoted supported Cu catalyst, with ground zeolite, which mixture is pressed or extruded into particles of the desired size. The catalyst: zeolite weight ratio can range from 10: 1 to 1:10, preferably 1: 1 to 1:10.

- Apply Cu to the zeolite itself. This can be done by (incipient wetness) impregnation of preformed zeolite particles, such as pellets or extrusions with a

Cu precursor, for example Cu citrate, drying, calcination. Then impregnate with the reduction promoter, for example Pt-nitrate, drying and calcination.

- The above-mentioned shapes are coated on a monolith.

The pyrophoric character of the zeolite systems has been greatly reduced, because on contact with the air the oxidation heat causes the water in the zeolite to evaporate. This can release 50 to 100 liters per liter of zeolite, which displaces the air and prevents temperatures in the catalyst bed from getting out of hand, leading to catalyst deactivation and incendiary situations. Coated on a monolith, the locally strong heat development is further inhibited by the rapid heat dissipation from the monolith.

5 In summary: 1. Less heat problems due to less Cu in the reactor.

2. Less Cu achievable by increasing the activity via increasing Cu dispersion and adding water absorbing materials (higher steam / carbon ratio).

3. Increase reducibility of highly dispersed Cu in process gas by adding reduction promoters (Pt).

15 4. Suppress pyrophoric character by "quenching" with steam from the water-absorbing material. Possibly coating on monolith.

Such variants are each considered to fall within the scope of the invention.

10134 76

Claims (28)

1. A fuel processor for producing a gas stream comprising hydrogen by catalytic combustion of a mixture comprising at least one gaseous hydrocarbon compound, water vapor and oxygen, the fuel processor comprising a gas flow path through which the mixture is passed and a CPO contained in the gas flow path. catalyst to which the mixture is fed for catalytic combustion, characterized in that the gas flow stage downstream of the CPO catalyst contains a plurality of series-connected HT shifts which, in use by the mixture leaving the CPO catalyst are respectively flown through. 2. A fuel processor according to claim 1, characterized in that the gas flow stage comprises heat exchangers between the CPO catalyst and the HT shift located closest to the downstream of the CPO catalyst and between the HT shifts, which exchange heat between the one hand the mixture which is supplied to the CPO catalyst and, on the other hand, the mixture which flows downstream of the CPO catalyst through the series-connected HT-Shifts. Fuel processor according to claim 2, characterized in that each HT shift has two opposite sides which form an input and an output of the HT shift, respectively, the HT shifts in a direction coinciding with the normal of said sides of the HT shifts are arranged relative to each other with an output of a first HT shift opposite an input of a second HT shift and the second HT shift being contained in a box-shaped chamber with a bottom and upright sidewalls in which the bottom lies between the entrance of the second HT shift and the exit of the first HT shift and the gas flow * 013478 path from the first HT shift to the second HT shift extending respectively along an outside of the bottom of the box-shaped chamber, between the heat exchanger and an outside of the upright side wall of the box-shaped chamber, between the second HT shift and an inside of the upright side wall of the box-shaped chamber to a space located between the inside of the bottom of the box-shaped chamber and the side of the second HT shift comprising the entrance. The fibrous dust processor according to claim 3, characterized in that each HT shift is contained in a box-shaped chamber. Fuel processor according to claim 4, characterized in that the heat exchangers comprise a tubular inner wall enclosing a space in which the HT-Shifts with the box-shaped chambers are accommodated. Fuel processor according to claim 5, characterized in that each HT shift is tubular in shape with two opposing open ends which form the entrance and the exit of the HT shift, respectively, with axial axes of the HT shifts at least substantially coincide with an axial axis of the tubular inner wall of the heat exchanger. Fuel processor according to claim 6, characterized in that the heat exchanger is further provided with a tubular insulation outer wall. Fuel processor according to any one of the preceding claims, characterized in that the gas flow path further comprises an LT shift 30 located downstream of the HT shifts, the fuel processor further comprising an inlet for adding water in use to the mixture fed to the LT shift to cool the mixture. Fuel processor according to claim 8, characterized in that the processor further comprises means 1013478 for adding the water via the inlet in the form of steam. Fuel processor according to claim 9, characterized in that the means comprise an electric heating unit or a hydrogen burner, a natural gas burner or a heat exchanger. Fuel processor according to claim 8, characterized in that the inlet comprises atomizing means for adding the water in the atomized state. Fuel processor according to any one of claims 8-11, characterized in that the LT shift comprises a tubular insulating inner wall and a tubular insulating inner wall arranged concentrically with each other, in use, the mixture containing the space flows between the tubular insulating inner wall and the tubular insulating outer wall and wherein the HT shifts and the CPO-CATALYST are accommodated in a space enclosed by the tubular inner wall. Fuel processor according to claims 7 and 12, characterized in that the tubular insulation outer wall of the heat exchanger coincides with the tubular insulation inner wall of the LT shift. 14. The fuel processor according to any one of the preceding claims 8-13, characterized in that the processor further comprises a PrOx located downstream of the LT shift in the gas flow path and an inlet for adding oxygen to the mixture containing the LT- has exited shift and flows to the PrOx. 15. A fuel processor according to claim 14, characterized in that a further heat exchanger is included in the gas flow path between the LT shifts and the PrOx for further cooling of the mixture. Fuel processor according to any one of the preceding claims, characterized in that the processor further comprises a vessel which is filled with water and / or is flowed through with water, the 10 1 3478 gaseous hydrocarbon compound and oxygen being further supplied to the vessel. for passing through and / or along the water to generate said mixture to be supplied to the CPO catalyst and means for controlling the temperature of the water to adjust the concentration of the water vapor in the mixture that is fed to the CPO catalyst. Fuel processor according to claims 14 and 16, characterized in that the processor further comprises a heat exchanger for exchanging heat between the mixture that has flowed through the PrOx and the water contained in the vessel so that the temperature of the mixture that forms the hydrogen-containing gas stream drops. A fuel processor according to any one of the preceding claims, characterized in that the processor further comprises a fuel cell for generating electric energy from the hydrogen formed. Fuel processor according to claim 9 or 11 and according to claim 18, characterized in that said means for forming steam or water spray comprise the fuel cell. 20. Fuel processor for producing hydrogen by catalytic combustion of a mixture comprising at least one gaseous hydrocarbon compound, water vapor and oxygen, provided with a CPO catalyst to which the mixture is fed for catalytic combustion, characterized in that the processor further comprising a vessel filled with water, the gaseous hydrocarbon compound and oxygen being further supplied to the vessel to be passed through and / or along the water to generate said mixture and means for controlling the temperature of the water to adjust the concentration of the water vapor in the mixture. 21. Device for generating at least a third and fourth gas stream from a first and second gas stream, the third gas stream comprising a mixture of the first and second gas stream, comprising a chamber enclosing a space containing a fan, the chamber is provided with a first and second inflow opening for, in use, supplying the first and second gas flow to the first and second inflow opening, respectively, and a first and second outflow opening, in use, the first and second gas flow being drawn in by the fan and fed into the first chamber, separated from one another, respectively, to the first and second outflow openings, the first outflow opening opening into a first outlet and the second outflow opening opening into the first outlet through a split, wherein 15 in the first and / or second outlet an adjustable valve is included for adjusting the ratio of the amount of gas originating from the first and second gas stream in the third gas stream from the first outlet, the fourth gas stream flowing through the second outlet comprising a part of the second gas stream. 22. Device as claimed in claim 21, characterized in that the chamber comprises a cylindrical outer wall enclosing a cylindrical space in which the fan is designed as a wheel, a rotary axis of which coincides with an axial axis of the chamber with the wheel being near. circumferential edge on both sides is provided with vanes and wherein the first gas flow extends on a first side of the wheel where the vanes are located and wherein the second gas flow extends on a second side of the wheel where the vanes are located. 23. Device according to claim 22, characterized in that the first and second inflow opening are arranged offset in an axial direction of the chamber in the cylindrical outer wall of the chamber, the first inflow opening and the first outflow opening at least substantially in a are arranged in the same plane that 101 347 8 is oriented perpendicular to the axial axis of the chamber and wherein the second inflow opening and the second outflow opening are arranged substantially in the same plane that is perpendicular to the axial axis of the chamber. 24. Device according to claim 23, characterized in that the chamber is provided with two opposite side walls which are oriented perpendicular to the axial axis of the chamber, the first side wall comprising a first circular groove extending around the axial axis, in which the first inflow and outflow opening is received and wherein the second side wall comprises a second circular groove extending around the axial axis, in which the second inflow and outflow opening is received and wherein the blades of the wheel extend along the first and second groove, respectively stretch out. The fuel processor according to any one of claims 14 or 17, characterized in that the processor further comprises an apparatus according to claim 22, 23 or 24, wherein the first gas stream consists of a mixture of air and a gaseous hydrocarbon compound and the the second gas stream consists of air, the third gas stream consists of a mixture of the first and second gas stream and the fourth gas stream consists of a fraction of the second gas stream, whereby the third gas stream is supplied to the gas flow stage and the fourth gas stream is added to the mixture added that is fed to the PrOx. 26. The fuel processor according to claim 25, characterized in that, in use, the fan rotation speed is modulated for modulating the third and fourth gas stream equally. 27. The fuel processor according to any one of claims 1 to 20 or 25, 26, characterized in that the processor is further provided with an absorber, through which the gaseous hydrocarbon compound is supplied for cleaning the gaseous hydrocarbon compound, the absorber being, for example, active includes cabbage. 28. A fuel processor according to any one of claims 16 or 17, characterized in that the processor is provided with an ionization vessel for cleaning the water used to obtain the mixture. 101 3478