Device for increasing or decreasing the oxygen content of air, and method of producing and of operating it

· 'Boosts PO / ES 1

The invention relates to an apparatus to increase or decrease the oxygen percentage in the air to be supplied to a consumer, in particular a combustion chamber, using a very thin semipermeable membrane which separates a first space having a higher pressure and having an input for normal air and an output of 02 ~ magret air, and a second room, which has lower pressure and having an output for (^ -enriched air, and further relates to a method for producing this device and a method for its operation.

In a known apparatus of this kind, especially intended for enrichment of innåndningsluft or combustion air with oxygen, is there used a membrane which is more permeable to oxygen than nitrogen and consists of silikonkautsjuk and disposed flat on the surface of a porous support. The membrane areas can be achieved in the connection, is small, resulting in that there also only be obtained small amounts of C ^ -enriched air. Admittedly, it is possible to increase the amount by increasing the differential pressure. But such trykkhøyning is undesirable for many purposes of use and is also, in all cases technical reasons only possible to a limited extent.

Furthermore, there is known a dialysis apparatus for blood purification which the porous hollow fibers in a number lower than 10,000 are combined to form a cylindrical bundle and arranged in a cylindrical capsule. The fiber ends are brought sealingly through the capsule walls. Blood is passed through hollow fibers inside. In its peripheral surface, the capsule has at one end an inlet and at its other end an outlet for cleaning fluid which is pumped through the space outside the hollow fibers in the capsule.

In this case migrate toxins from the blood into the cleaning liquid, not due to any difference in pressure, but as a result of a difference in concentration. For that toxins will have sufficient time to take over in the cleaning liquid, the hollow fibers have a length of 220-350 mm.

The invention is an object to provide instructions for an apparatus of the initially defined kind with which it is possible in connection with small dimensions to treat air in larger amounts and / or lower pressure differences, so it is in particular suitable for the supply of combustion chambers .

This object is achieved according to the invention solved in that the hollow fibers with microscopic wall membrane exhibiting on a peripheral surface and are arranged parallel to each other in large numbers in a capsule whose opposite end walls the ends of the hollow fibers runs 2 through, while these ends is sealed on its outer circumference.

When the inner or outer peripheral surfaces are provided with a membrane results in an extremely large membrane surface area. It is therefore possible to provide a small amount (^ -enriched air, eg. For breathing purposes, with very small pressure differences, eg. Depending on lung power, or common output differences of about 2 Pa to obtain very large amounts Oj -enriched air, eg. combustion air to a motor vehicle or a guy. The microporous wall provides a sufficiently stable base for an ultra-thin membrane.

The hollow fibers can here form a carrier membrane is applied. This makes it possible to use a hollow fiber with optimum wear properties. However, the hollow fibers can also consist of a membrane material so that there is obtained a structure integral with a porous support portion and a non-porous membrane. In the event requires the membrane to be placed afterwards, as it can be provided already in the preparation of hollow fibers, whether by controlled pore formation or by closing the pores along a peripheral wall. Also available a particularly good connection between carrier and membrane. Alternatively, hollow fibers also have stiffening in its wall.

Suitably forming hollow fibers inner cavity the first space and the room in the cap outside of the hollow fibers the other chamber. Then the inner cavity of the hollow fibers causes the higher pressure, albeit a slight elastic expansion of the hollow fibers could take place, but no compression and hence associated decrease of average ennomgangstverrsnittet.

There shall be at least 100,000 hollow fibers, preferably more than 0.5 million hollow fibers. Appliances with more than 5 million hollow fibers can be without difficulty realizing. Especially, as many hollow fibers may be arranged approximately parallel to each other in a hulfiberbatteri that there emerges a membrane area of ​​15 to 500 m2.

Particularly advantageous are hollow fibers arranged in a capsule, while at least one utløpssamlerom extending along a capsule side wall extending parallel to the hollow fibers. The Oj-enriched air can thus be sucked to the outlet collecting space substantially across the hollow fibers, so strupningsmotstandene becomes relatively small.

In particular it can be ensured that the capsule has rectangular end walls having a relatively long and relatively I> 3 short side and the outlet collecting space extending along a capsule side wall extending between the end wall of the long sides, and substantially over the entire area of ​​this wall . Further, another, similar utløpssamlerom extend along the opposite side wall. In this way it is ensured that all the hollow fibers are connected to a utløpssamlerom via a relatively short distance. Consequently, the pressure drop between the membrane and utløpssamlerom correspondingly small. When the hollow fibers are not completely straight, leaves they, even if they are closely packed sufficiently large intermediate channels for gas. Alternatively, such channels, however, also be constructively conditioned by a similar arrangement of hollow fibers or by using hulfiberavsnitt larger diameter.

Preferably, the hollow fibers an outside diameter of 100 to 400 microns, preferably about 200 microns. In consideration of the achievable wall thicknesses obtained a sufficiently large internal cross section which does not present too great flow resistance to the air flowing through.

The hollow fibers do not need to have greater wall thickness than 20 microns, and even less 6pm is enough. This provides a sufficient stability in conjunction with minimal resistance to the through-Tred air.

It is advisable to keep the length of the hollow fibers at least possible, especially smaller than 200 mm and preferably 100 mm, that the air with sufficient oxygen ratio must be offered to the membrane portion at the rear end of the hollow fibers.

Regarding hollow fibers pores, one must take into account that they firstly must be small enough not to influence the secure rejection of the membrane, but for the other should be large enough not to impede gas transport from resp. the membrane adversely, In this connection it is advantageous that the pore size of the far-reaching extent is in the range 0.1 pm to 1 pm. Preferably the pore size decreases from the membrane. The small pores for better utilization of the membrane does in this connection only to extend over such a thin layer that does not influence appreciably the gas transport. In particular, the size of the pores that block the membrane, constitute 10 to 50 nm.

In a preferred embodiment, it is ensured that the membrane sits on hollow fibers inner circumference. This allows particularly long service life because the membrane is well protected and avoid 4 any mechanical stress that the there may appear at at each other lying hollow fibers with outer membrane.

Furthermore, it is advantageous to interpose an air filter before the inlet to the first space. Thus it is ensured that the hollow fibers inner cavity blockage.

By incorporation of a motor vehicle should the hollow fibers extend in the longitudinal direction thereof and have its one end near the vehicle front side. Thus, it is possible to utilize the wind to drive the air through the hollow fibers when it seeks to apply the oxygen enriched combustion air in the engine.

To drive air through the hollow fibers cavity there may also use a blast. This can also be built in addition to a motor vehicle.

If the combustion chamber is part of a combustion power engine or a furnace, should the membrane area may be selected so large that the combustion temperature is over 2500 ° C, especially at about 3000 ° C. The high combustion temperatures leads to a raise in the efficiency and a reduction in fuel consumption. The fuel force-machines, it is also unnecessary to let the air-fuel ratio range in dependence on the full load and partial load, whereby for gases construction and supervision is significantly simplified. When ignition speed is very large, the ignition timing is dropped to near top dead center. This means an additional saving of fuel and reduces the susceptibility to ignition. The decreased propensity banking makes it furthermore possible to increase the compression, whereby the efficiency is raised further. Thanks to the rapid ignition sequence avoided moreover uneven heat transfer to the combustion chamber wall, which leads to a lower coolant temperature and less ventilatoreffekt. Besides, it provides rapid ignition sequence a smooth time of a burning powerhouse. The amount of combustion air required for the operation of such a combustor, are admittedly very large. For example, the it for a two liter engine of 100 m / h. A correspondingly large membrane surface area, however, can without difficulty provide by means of the hollow fibers.

Furthermore, it is advantageous if there is assigned to the combustion chamber exhaust channel into one direction to decrease the share of nitric oxide. Thus, where taking into account the fact that there on the to-promoting high combustion temperatures obtained a large amount of nitric oxide, for example. 5 volume percent at 2,700 ° C Overall emerges t 5 thus a device corresponding to a normal combustion plant (supplying fuel and normal air, flue gas with low content of harmful substances), but considerably better efficiency with corresponding savings of fuel.

For example, the exhaust duct in its first part exhibiting a heat insulation that slows the cooling of the exhaust gases and thus favors decomposition of nitric oxide. Another possibility is to assign exhaust channel at least one device for reaksjonsfri exhaust heating.

A method of manufacturing an apparatus in which the hollow fibers are provided with a membrane according to the invention wherein the hollow fibers first prepared and then treated with a coating fluid containing the membrane material, and then this is crosslinked on the hollow fibers. The coating fluid can be easily applying hollow fibers circumferential surfaces. Also a dosage to obtain the desired film thickness is possible.

To achieve particularly thin membranes, it is recommended for the coating fluid contains a solvent or dispersing agent for the membrane material and this solvent is removed. In particular, there is used a solvent or dispersing agent which is at least partly escape through the hollow fibers pores. The molecules must therefore be smaller than these pores. This enables an internal coating. By an exterior coating increases the rate at which solvent resp. the dispersant can be removed.

The removal of the solvent or dispersant, for example. happen in that there is applied a pressure difference between inside and outside of hollow fibers. Instead of or together with this, solvent or dispersant is removed by evaporation resp. evaporation. Often it is advantageous to cross-linking of the membrane material is initiated already before the coating treatment. Then there including already occurs larger molecules, it is easier to remove solvent through hulfiberveggen without membrane material while being taken. The coating fluid may also contain a catalyst. In this, there may also be a by-nights component. Another possibility consists in advance to supply hulfiberflåtene to be coated with a crosslinker component or also to allow the hollow fibers consist: of a material exhibiting reactive groups which cause crosslinking. If the catalyst contained membrane material is well flowable, it is also possible to use it directly as the coating fluid.

6 The application example. effected in the manner that the hollow fibers are moved past an application station for the coating fluid. They may also be dipped in the coating fluid or preferably sprayed with it.

A particularly advantageous opportunity is located in for the preparation of the internal cavity during the manufacture of the hollow fibers to introduce a filler containing membrane material in the fiber material.

A method of operating the apparatus according to the invention wherein there by enriching combustion air with oxygen in the combustion chamber is provided a combustion temperature of more than 2500 ° C, and that cooling of the exhaust gases leaving the combustion chamber, in a temperature range of at least 200 ° C occurs slower than in a subsequent temperature range. When the combustion temperatures sought with the aim of high efficiency, should the exhaust gases cool down through a substantial temperature range. The smaller the cooling rate is, the larger the remaining nitrogenoksydmengde. Preferably remains exhaust gases in the temperature range of slow cooling for at least 0.3 s.

Especially, the cooling rate in the temperature range of slow cooling will be approximately nitrogen oxides temperature dependent decomposition rate, i.e. decrease in this temperature range.

Conveniently there is furthermore on the initial temperature of the area with slow cooling maintained at least at 1400 ° C. The temperature range of · slow cooling is therefore on a relatively high level where it is possible to utilize high decomposition rate.

In the following the invention will be elucidated in more detail by embodiments illustrated in the drawings.

Fig. 1 shows the cross section of the multiple hollow fibers coated with a membrane.

Fig. 2 shows in perspective an apparatus according to the invention sectioned along line II-II in FIG. 3.

Fig. 3 shows the horizontal section of the apparatus of FIG. 2.

Fig. _4. viser_lengdesnitt of end portions of hollow fibers made of modified shape in an end wall of the capsule.

FIG. 5 shows the section VV of Fig. 4.

Fig. 6 shows schematic longitudinal section of an apparatus for producing hollow fibers.

Fig. 7 is a schematic cross section of one embodiment of a hollow fiber with internal membrane ..

Fig. 8 shows a similar manner a modified embodiment 7 of the fiber.

Fig. 9 schematically illustrates the course of a method of providing an internal membrane.

Fig. 10 shows the cross section of a portion of a device to provide a outer membrane.

Fig. 11 shows a corresponding longitudinal section of this apparatus.

FIG. 12 illustrates the equilibrium air: nitrogen oxide in a graph of nitrogenoksydandelen as a function of exhaust gas temperature T.

FIG. 13 is a graph of nitrogen oxides cleavage half-life tH as a function of exhaust gas temperature T.

FIG. 14 is a schematic diagram of the path of the exhaust gas temperature as a function of time during cooling.

Fig. 15 shows schematically a combustion power machine with an apparatus for reducing nitrogenoksydandelen in the exhaust gas.

Fig. 16 shows the cross section of the apparatus along the line XVI-XVI in FIG. 15.

Fig. 17 shows the schematic cross section of another embodiment of an apparatus to reduce nitrogenoksydandelen.

Fig. 18 shows yet another embodiment of such apparatus.

Fig. 19 shows a fourth embodiment of such an apparatus, and Fig. 20 illustrates schematically the incorporation of the apparatus of the invention in a motor vehicle.

In FIG. 1 is seen a lot of each other disposed hollow fibers 1 which internally coated with an ultrathin semipermeable membrane 2. The hollow fibers have eg. an outer diameter d of 50 to 400 microns, particularly 100 to 200 m and a wall thickness s which is from less than 6 microns to 20 microns, especially 5 to 10 pm. The membrane eg. a thickness of 100 nm. Hollow fibers cavity 3 forms a first compartment A, and the room outside of the hollow fibers forming another room B. Excluding these two rooms at different pressures, wandering the gas from the room with higher room with lower pressure, and membrane 2 is here more permeable to oxygen than nitrogen.

Figs. 2 and 3 shows an apparatus which utilizes an extraordinarily high number of the described hollow fibers. A battery 4 with length 1 to 10 cm, height h of 20 cm and width 60 cm B contain from 6 million or more hollow fibers 1 extending parallel beside each other in the longitudinal direction and provide a membrane area of ​​about 180 m or more.

8

Fiber battery 4 is disposed in a capsule 5 with two end walls 6 and 7, the ends of the hollow fibers 1 are inserted under the seal at its outer circumference. Beneficial consists end walls 6 and 7 of plastic which adheres circumferential surfaces of the fibers together. The first space A has thus the front end wall 6 an inlet 8 through which normal air can be led into the inner cavity 3 in the hollow fibers 1.

Behind the wall 7 is located a corresponding outlet 9 which oxygen-poor air dissipated. The front inlet 8 sits an air filter 10. The whole device can be incorporated in a dotted suggested motor vehicle 11 near its front 12 with hollow fibers 1 for extending lengthwise of the vehicle as the wind makes review of a sufficient amount of air through the hollow fibers. Instead, or in addition, there sit a ventilator 13 in the end.

In fiber battery 4 are hollow fibers 1 arranged in parallel rows 14 which leave between them channels 15. These channels open into utløpssamlerom 16 and 17 included in the second space B, which via a common outlet 18 is connected to a suction pump 19 whose transport page 20 leads to a consumer, eg. a burning powerhouse. Output collecting space extends over the entire area of ​​upper and lower capsule wall, respectively 21 and 22, thus over an area 1 x b. In this way, for example. the overall surface of each hollow fiber without disturbing resistors connected to the outlet 18 from the second space B. channel width may be relatively low, as also the fibers are small and the maximum extent in the vertical direction only constitutes h / 2, in the embodiment thus 100 mm.

In the embodiment of FIG. 4 and 5, the hollow fibers 51, which are coated with the membrane 52 on the outside, provided with section 53 of larger diameter. These are located here at the ends of the hollow fibers and is sealed embedded in an end wall 6. As shown in FIG. 5, such hollow fibers in the region of their passages 53 may be arranged closely next to one another whereby in the other stream of the hollow fibers left one channel 54 which in this case have a wavy shape.

Such sections 53 may also be provided on any place of the hollow fibers length. They do not have to lie in a common plane, since there already by rejection of a section 53 of the normal diameter by a nabohulfiber remains a sufficient channel.

The preparation of such hollow fibers 51 with sections 53 with larger diameter may be by several precautions described in relation "* 9 connection with FIG. 6. Here occurs a spray head 55 which exhibits an annular nozzle for supplying material 57 for the hollow fibers 51 and a central orifice 58 through which there led into a gaseous filling agent with a pressure p. This pressure p is intermittently raised as indicated by pulses 59 . thus arises the extended section 53.

Fig. 7 shows a hollow fiber 1 with inner membrane 2 in cross section. It is seen that the outer pores 60 is greater than the inner pores 61 located just below the diaphragm 2. While the inner pores for example. has a size of 15 nm, the pore size increases in excess of about 1 μτα. The pores are interconnected.

In FIG. 8 is shown another embodiment wherein a hollow fiber 62 consists of the same material as the membrane 63. Here again, the pores 64 smaller in the direction from the outside inwards. Bottom poreskikt however closed, so the desired cone 63 emerges.

The membrane material must be selected in the interests of gas permeability and Oj - ^ - separation factor. For this faith there are different possibilities. Especially recommended is silicone rubber (dimethyl polysiloxane) or silikonkautsjuk polycarbonate copolymer of dimethyl polysiloxane and bisphenol A with high content (over 80%) of dimethyl polysiloxane. Silikonkautsjuk has a separation factor between oxygen and nitrogen of 2.2, then the gas mixture is in the room with the lower pressure has an oxygen content of about 30-35 volume percent. Appropriately used cold vulcanizable membrane materials, and in this connection should be wholly or largely forgo fillers resp. pigments for not influencing the membranes properties. However, also comes hot vulcanizable materials into consideration.

Crosslinking of membrane material may occur using a fornetterkompbnent and a catalyst. As crosslinker component can be the most diverse known materials for this purpose come into consideration, preferably ortho- or polykiselsyreestere, alkyl trialkoxysilanes or siloxanes having Si-H bonds. Such crosslink components can be admixed with the vulcanizable membrane material for coating, but may also be applied to hollow fibers circumferential wall before coating. Exhibits hulfibermaterialet active groups, such as hydroxyl or alkoxy groups, one will also be able to renounce the use of a crosslinker component.

As catalysts will most diverse known materials in consideration. Particularly well suited are organic peroxides, amines 10 or carbon acid salts, eg. stannous octoate or dibutyl tin dilaureat.

The membrane material can be mixed with the crosslinker component and the catalyst and then dissolved, respectively. dispersed after degassing.

A one .to fireprosentig solution resp. dispersion is recommending. As solution resp. dispersants going aromatic or aliphatic hydrocarbons (particularly petroleum ether), as well as chlorinated hydrocarbons into consideration.

The hollow fibers should consist of a polyaddisjons- or condensation product. Suitable particularly polyester, polyamide, polysulfone, sellulose and selluloseacetat. Finest stiffening of other materials is possible.

Fig. 9 schematically illustrates the course of process by applying a membrane 2 on the inside of a hollow fiber 1. In a first step 65 the membrane material 67, a catalyst 68 and a crosslinker component 69 mixed in a container 66. Then, the mixture in a step 70 mixed with a solvent 71.

After a certain rest time during which there may already be a slight crosslinking, the solution 72 in a step 73 inserted into the interior of hollow fibers 1. In a step 74 is where the outside at room temperature produced a negative pressure -P, whereby the solvent evaporates 'and carried away outward through hulfiberveggen. The porous wall acts in this context as a filter that allows the solvent to pass, but keeps membranmaterialet.tilbake inside. of hollow fibers. In a step 75 is there in an oven supplied heat H at about 50 ° C to yield residues of solvent is completely removed and the crosslinking is completed accelerated.

This procedure is simplified in that the hollow fibers 1 is already mounted in the apparatus. For now, the solution may just slett.føres through inlet 8. It offers neither the difficulties to bring the capsule at an elevated temperature. Membranes prepared in this way is mechanically protected and is affected neither by a further processing.

In the embodiment of FIG. 10 and 11 are two rollers 76 and 77 each provided with a circumferential groove 78, respectively. 79. The two circumferential grooves are dimensioned such that they provide a passage 8 slightly larger than the cross section of a hollow fiber 81.

Via a hopper 82, a mixture of flowable membrane material, catalyst and crosslinker component applied over roller 76, which rotates in the corresponding arrow direction. The material is 11 to the outside of the hollow fibers 81. The passage 80 determines the thickness of the applied layer. The residue is wiped off and can be captured again. The hollow fibers can then be passed through an oven for curing and then wound up. Instead of the funnel 82 there may be used one annular die to apply the vulcanizable membrane material.

The material can also be sprayed on or applied by dipping.

In this way it is also possible to apply the dissolved membrane material.

Another possibility is the embodiment of FIG. 6 appending membrane material to filler - the gaseous filler agent in atomized form and the liquid filler for example. disintegrate.

In the diagram of FIG. 12 is NO ratio in volume shown as a function of exhaust gas temperature T. The curve C separates an area 110 which is formed NO, from an area 111 where NO is cleaved. To the left of the dashed 500 ° limit located an area 112 where NO is metastable. It is seen from this that the NO proportion in the exhaust gas rises abruptly with increasing temperatures -and at 2700 ° C amounts to about 5 percent by volume.

In FIG. 13 illustrates curve D cleavage half-time t ^ of NO as a function of exhaust gas temperature T. It is seen that NO is decomposed virtually immediately at 2700 ° C, at 1/2000 s at 2200 ° C at approximately 0.6 s at 1700 ° C, for several minutes at 1200 ° C and during several weeks at 700 ° C.

In FIG. 14 is the exhaust gas temperature shown as a function of time t. The dashed line marks the exhaust gas output from the combustion. the power machine without regard to scale. In the area below 700 ° C, where practically no longer expected any NO decomposition. Curve E shows the known case when a combustion took place at about 2,000 to 2,200 ° C and exhaust gas exiting from the combustion power machine with approximately 1.000 ° C. In eksosbendet occurs further slagformig cooling, so the exhaust gas contains a considerable proportion of det'NO that existed at a higher temperature.

Curve F shows a cooling stream in accordance with the invention by the same ratio in the combustion power engine. In a first temperature range 113, which here extends from slightly above to slightly below 1000 ° C, the cooling is retarded. First, in the following temperature range 114 occurs where a sudden cooling. Said temperature range 113 traversed during one time of ca. 0.5 s. When there in the first temperature area 113 considerably be degraded nitrogen oxides and nitrogenoksydandelen before the rapid cooling, therefore 12 is less than in the case of the curve E, have also after cooling a smaller nitrogenoksydandel in the exhaust gas.

The same applies to the curve G, which characterizes the event that combustion as a result of a heightened oxygen ratio in the combustion air occurs at about 3000 ° C and exhaust gas output temperature amounts to approximately 1,700 ° C. Here, cooling is performed slowly in a temperature range 115 that reaches down to 1300 ° C and lasts for a time of about one second. In the subsequent temperature range 116 occurs when a rapid cooling. In this manner it is possible in spite of the high initial values ​​at the output of combustion power machine to reduce the nitrogen percentage in the exhaust gas at low values ​​can be justified. In practice dvelingstidene also be chosen shorter or longer.

In the embodiment of FIG. 15 and 16 receive a combustion force machine 117 via a line 118 supplied combustion air if the oxygen ratio has been raised in a device 5. The waste gas is brought through a channel 120 comprising a first tube section 121, a container 122 and a pipe section 123 which leads to a muffler. Tube section 121 and the container 122 is provided with a thermal insulation 124. In the container sits a spiral-shaped wall 125. The exhaust gas which is supplied in the center, therefore traverses a spiral-shaped channel 126 from the inside outward. As a result of the zinc heat efficiency and the relatively long time when the exhaust gas is exposed to these conditions, obtained the desired slow cooling through the first temperature range.

In the embodiment of FIG. 17 includes an exhaust duct 127 to a first tube section 128, a container 129 and a second tube section 130, all surrounded by a thermal insulation 131. In the container there is on both sides of a central chamber 132 disposed walls extending alternately from respective distance, so where obtained two labyrinth shaped flue gas duct sections 134 and 135. at sufficiently long flow path in the vessel 21 can optionally also the underside of the side walls relinquish the outer insula tion, since the exhaust gas flowing through the second channel section 136 in the container 129, act as heat insulation in the preceding paragraph.

In the embodiment of FIG. 18 shows an apparatus 137 three series-connected containers 138, 139 and 140 interconnected by choke solution sections 141 and 142. In this manner, obtained one lyddemperfunksjon. The associated thermal insulation is not indicated. From container 140