Carbonization reactor for the combined production of construction materials and electricity by means of sunlight

Abstract

The invention describes an energy-efficient method for simultaneous generation of carbon fibers and electricity by means of bundled sunlight for the CO2-neutral production of pressure- and tensile-stable building materials, which are able to bind anthropogenic carbon, in case the carbon fibers are produced from vegetable oils. Through the oil generation by photosynthesis, carbon dioxide is being split off and carbon is being bound in the oil, as well as oxygen is being released.

Due to the fact that the production energy has a purely regenerative character, it is ensured that in the short-term not only carbon neutrality can not be introduced, but carbon is permanently withdrawn from the climate system of atmosphere and ocean.

The energy efficiency is based on the principle to heat the carbon fiber to be produced directly up with bundled sunlight, which is made possible by the fact that the original PAN fiber becomes dark during the oxidation and pyrolysis process and finally becomes an almost ideal black body.

The resulting heat is used subsequently or simultaneously to the material production of the fiber for the production of electricity, which corresponds to the classical combined heat and power principle, in order to additionally increase the efficiency in carbon fiber production already increased by this process, by delivery of energy in form of high valuable electricity.

The fibers are used on demand in combination with mineral material as a substitute for CO2intensive construction materials such as steel concrete, steel and aluminum.

After use the carbon fibers are separated from the stone by peeling and stored away without large energy expenditure in underground or above-ground camps without difficulty, whereby the carbon bound in the carbon fiber remains permanently bound.

Thus, the economy is becoming the driving force behind advancing decarbonization with a negative algebraic sign.

Claims

1. A system for production of carbon fibers from synthetic plastic fibers by means of bundled sunlight, comprising: synthetic plastic fibers which are being moved forward continuously within a transparent tube as parallel bundles along a focal line of light-focusing arrangements and becoming by dark in color, which is required for oxidation by continuous heating; a self-optimizing energy sink of light, getting so dark black, that fibers are being heated without indirect heating but only by direct irradiated sunlight, wherein the fibers reach the necessary high temperatures of at least 1800 C. needed for a pyrolysis process to occur and; wherein a grade of conversion of light into heat is steadily growing; and whereas the pyrolysis process is being controlled by cooling from outside through cooling gases or liquids in such a way, that transparent vessels or guiding-tubes guiding the pyrolysis process are not melting due to high carbonization temperatures within an area of a heating zone of the high-temperature pyrolysis process; and wherein a tube system, surrounds fiber roving, wherein the fiber roving -is being protected against exceedance of critical temperatures and; wherein the tube system consists of: an inner tube, comprising a carbonization tube, a section of the carbonization tube, wherein oxidization takes place called an oxidization zone, and, a section of the carbonization tube in which the pyrolysis process happens called a pyrolysis zone, and a cooling zone of the carbonization tube.

2. The system of claim 1, wherein bundling of sun rays is being generated by means of parabolic mirrors or focusing glasses; wherein the glasses or mirror comprise at least one of fresnel lenses with or focusing geometries from at least one of mirrors, glass, quartz-glass, diamond or a combination thereof.

3. The system of claim 2, wherein the parabolic mirrors or focusing glasses are being arranged along a straight or curved focal line.

4. The system of claim 1 wherein, the fibers are carbonized and guided as a single fiber or as a fiber bundle in the carbonizing tube and are moved along and at the center of the focal line.

5. The system of claim 1 where in the carbonization tube is being filled with -gas to be transported.

6. The system of claim 1, wherein the gas within the pyrolysis tube contains oxygen or excludes oxygen depending on a phase of oxidation or pyrolysis.

7. The system of claim 1, wherein the pyrolysis tube in the heating zone is passed through a second transparent tube for cooling, and wherein a cooling transparent gas or a cooling transparent liquid is guided and moved between the tubes, which, via a heat exchanger which supplies a conventional power plant with water steam turbines with necessary heat energy.

8. The system of claim 1, wherein the pyrolysis tube is surrounded in the oxidation phase and the pyrolysis heating zone by a heat-insulating vacuum with help of an additional transparent tube-walls.

9. The system of claim 1, wherein the pyrolysis tube is cooled externally in such a way that the fiber is reaching the end of the process string and the temperature necessary for a sufficient or complete carbonization without the walls of the pyrolysis tube reaching their melting temperature.

10. The system of claim 1 wherein a region of the pyrolysis tube comprises a second tube surrounded by a third tube or vessel, and wherein a heat-insulating transparent gas or a vacuum is arranged between the second tube and third tube.

11. The system of claim 1, wherein the carbon fiber string in the center of the pyrolysis tube along the focal line is held by a material having a higher melting point than the maximum pyrolysis temperature required for carbonization, such as high-temperature-resistant steel, tungsten or molybdenum.

12. The system of claim 1 wherein-inlet pipes are arranged at regular intervals on the carbonization tube, through which holding structures are guided and adjusted and, which are tempered; and wherein purified gas is being blown on demand, and which must be replenished;.

13. The system of claim 1, wherein PAN fiber in the oxidation phase is sufficiently pigmented for heating by means of solar light.

14. The system of claim 1 wherein a holding phase follows the pyrolysis phase after heating up to maximum temperature, in which the parabolic mirror zone terminates and no further light energy supply takes place, and wherein the carbon fiber, which has been brought up to glowing temperatures during the pyrolysis heating phase, will be kept glowing by means of inner mirroring of the carbonization tube such that radiation by the glowing carbon string reflects back onto the string and the temperature will be kept at a largely constant level.

15. The system of claims 1 where-in during the holding phase, the carbonization tube is surrounded by a vacuum and solely cooled by nitrogen gas flowing within the tube.

16. The system of claims 1 wherein cooling phases follows the holding phase, wherein the tubes transparent and the radiation is reflected on black bodies and converted into heat or wherein the tubes are not transparent wherein the radiation is heating up a non-transparent tube wall through which the heat is being moved away by convection.

17. The system of claim 1 wherein any form of radiation and heat energy is supplied to a water circuit for the generation of electricity in at least one of the oxidation, pyrolysis and cooling phases via heat exchangers.

18. The system of claims 1 wherein transparent tubes are partially made of or all made of at least one ofquartz glass, glass or plastic.

19. The system of claim 1, wherein the interior space of the carbonization tube is leakproof due to the introduction of PAN fiber.

Description

[0109] One of the many possible embodiments of the invention describes in FIGS. 1 and 2 an arrangement with conventional linear-parabolic mirrors (10) or alternatively in a row arranged Fresnel-lenses or linearly arranged focusing balls, whereas within their focus (F), however, in contrast to a conventional power station based on bundled sunlight (So), there does not exist primarily a heating pipe with a liquid which is to be heated, but rather the starting materials to be heated in preparation of the production of carbon fibers, for example in the form of polyacrylonitrile or in short PAN fibers (1a) in FIG. 3, for example Dralon fiber.

[0110] These fibers are driven individually or in the bundle at a specific speed through the longitudinally formed focal point (F) or the aligned foci, ie along a focal line (Z), and thereby slowly but steadily heated by the bundled sunlight (So).

[0111] The process takes as long as the carbon fiber needs to get the starting fiber of polyacrylonitrile to take up the necessary thermal energy for the oxidation process to up to approx. 300 C. and for the subsequent carbonization process underexclusion of oxygen to up to 1500-1600 C. or even up to 3000 C.

[0112] For this purpose, the PAN fiber is being guided within a transparent tube of, for example, glass, quartz glass or glass ceramic (2), which in the oxidation phase and the carbonization phase is filled with different, likewise transparent gases (2a) in the oxidation phase (FIGS. 3) and (2b) in the pyrolysis phase (FIG. 4). In the oxidation phase in FIG. 3 the fiber bundle is located in an oxygen-containing gas mixture (2a) and is heated up to about 300 C. during this phase.

[0113] The glass tube (2) surrounding the fiber bundle is thereby not subjected to critical temperatures which would necessitate cooling of the tubes because the melting temperature of glass is not being reached.

[0114] For this reason it is possible during this phase to use a the tube (2) surrounding vacuum (3a) with the aid of a tube (4) surrounding the tube (2) in order to avoid unnecessary heat losses during this phase.

[0115] FIG. 3 shows how first the PAN fiber string is guided in the oxidation phase.

[0116] The guide rings (5) are being held at regular intervals in the middle of the oxidation tube by wires (6) from temperature-resistant material such as stainless steel, tungsten or molybdenum. The continuum around the PAN fiber string consists of oxygen-containing gas (2a). The rings preferably consist of temperature-stable, non-corrosive metal, tungsten or molybdenum.

[0117] The wires are passed through tubes (7), which are crossing the cylindric tubes (2) and (4), whereas the length of the wires (6) is adjusted electronically controlled by winding rollers (9) in order to hold the fiber string in the focal line, whereas at the same time gas (2a) can be blown through the tubes (7) in order to supply oxygen consumed by oxidation (8a).

[0118] In the carbonization phase (FIG. 4), the carbon fiber (1b) to be carbonized or the carbon fiber being formed respectively is located in a space filled with nitrogen (2b) in order to prevent from further oxidation and the burning of the material by further heating up to 800 C. at first and later onto up to 1800 or even 3000 C. during the pyrolysis process, in which the new chaining of the carbon atoms (carbonization) happens, which is responsible for the later on high tensile strength and stiffness of the carbon fiber, takes place.

[0119] Since the transparent glass tube (2)carbonization or pyrolysis tubewould melt at the high temperatures required for the pyrolysis, since the gas (2b) also reaches temperatures exceeding the melting temperature of the tube (2) to form a completed continuum of nitrogen (2b) or another transparent oxygen-free gas around the fiber string, and at the same time allow the bundled light to pass through to the fiber string for heating it through the wall of the glass without great optical resistance, the tube needs to be cooled externally by a transparent gas, for example air, or a suitable transparent liquid, for example temperature-resistant silicone oil (3b).

[0120] For this purpose, the inner glass flask is surrounded by a second enveloping glass flask (3) so that this cooling gas or the cooling liquid (3b) deliberately removes such an amount of thermal energy that the inner glass tube (2) always remains at a temperature below its melting point.

[0121] As long as this heated cooling gas or heated cooling liquid (3b) in turn used a cooling water circuit with a heat exchanger for its own cooling, electricity can be generated from the heat dissipated thereby by means of conventional power station technology with steam-turbine-driven generators.

[0122] The heat generated during the carbonization process is thus simultaneously used for the generation of electricity.

[0123] In order to optimize the heat supply of the medium (3b) towards the electrical energy-producing systems and thus to keep the total heat losses as low as possible, FIG. 4) shows how the second glass wall (3) is being surrounded by a third glass wall and the space between these two outer glass walls is provided with a vacuum (4a).

[0124] In this way, the heat generated during the carbonization process is optimally used for the generation of electricity, and the up to now substantially more inefficient carbonization of the carbon fiber by help of electrical power heating, is being replaced by a self-amplifying darkening process and corresponding heating by sunlight.

[0125] Within the regions of the higher temperatures, succeeding the oxidation phase to up to about 800 C. and the pyrolysis phase up to 1800 C. and above, it is shown in FIGS. 4 and 5, how the fiber string is being guided into the pyrolysis phase.

[0126] The guide rings (5) are held at regular intervals in the center of the pyrolysis tube (2) by wires (6) made as well of extremely temperature-stable material such as tungsten or molybdenum.

[0127] The continuum around the PAN fiber string consists in the pyrolysis phase of a gas which does not contain oxygen, for example nitrogen (2b). The rings preferably also consist of temperature-stable tungsten or molybdenum, which resist temperatures which are above the pyrolysis temperature.

[0128] The wires are passed through tubes (7) which pass through the walls of the cylindrical tubes (2), (3) and (4) and adjust the length of the wires (6) electronically via winding rollers (9).

[0129] At the same time, nitrogen (8b) is blown through the tubes (7), which is being discharged at the outlet of the carbon fiber string from the carbonization tubes and purified in order to be reused.

[0130] FIG. 7 shows a cross-section through the carbonization tube in the region of the pyrolysis-heating-zone in FIG. 8.

[0131] FIG. 8 shows a section through the entire carbonization track, beginning with the oxidation phase (11), in which the required heat energy is supplied either by means of parabolic mirrors or via electric heating for the oxidation of the PAN fiber, via the pyrolysis heating phase (12) by means of parabolic mirror heating and holding phase (13) with internally mirrored tube, up to the subsequent cooling phase (14), as well as the parabolic mirrors in zones (11) and (12).

[0132] The pyrolysis zone (12) is adjoined by a holding zone (13), whereby the pyrolysis time is adjusted by itsin relation to each otheradjustable length and function of the pyrolysis temperature and feed rate of the fiber.

[0133] Since the fiber itself emits radiation in the visible light range at pyrolysis temperature, this reflection is prevented by a full reflection mirroring (9a) on the inner wall of the pyrolysis tube in the holding phase following the heating phase (FIG. 6), so that the radiation energy is preferably suffering from as less losses as possible, so that the pyrolysis temperature can be maintained for a further distance without reheating through the parabolic mirrors.

[0134] The need for the parabolic mirrors is not required in this section, only the inner mirroring (9a) of the inner tube or alternatively the outer tube is required.

[0135] A vacuum (3a) ensures also at this point the necessary insulation against heat losses in the holding zone.

[0136] Following the temperature holding phase (13), the cooling phase (14) follows, in which a single-walled or double-walled tube can be used.

[0137] The cooling takes place by convection of a cooling gas in the inner tube, via the additional convection of a liquid or a gas within a second tube layer, which may not necessarily be transparent, but may be light-absorbing, or by radiation through a transparent tube system onto a black body, which is used as a heating system within a heat exchanger system, ie is cooled by water, whereas the heated water is also being used for the generation of electricity.

[0138] The described arrangement initially means a factor of 3 in the increase in efficiency compared to a process, in which electricity is being produced at first by conventional CSP parabolic mirror technology to serve for the carbonization of the fiber, since the efficiency of the power generation can be only at a maximum of 35% due to the associated heat loss.

[0139] Since, in the carbonization reactor described here, the light is initially converted to at least 45% into carbonization energy in the form of heat on the carbon fiber itself, the utilization of the light is therefore nearly twice as high as in the conventional method of primary generation of electricity and since additionally about 30% of the total heat is converted into electricity energy, a total utilization of the light energy of 75% can be assumed.

[0140] Cement burning or steel cooking can hardly be done with this principle, which is why the carbon fiber production with sunlight light in front of the background of the significantly higher energy efficiency, the low weight and the possibility of binding of carbon of anthropogenic origin is more sustainable than the production of conventional materials.

[0141] Even the production of carbon fibers of fossil origin would benefit this process superiority to conventional processes and methods, even if at first the carbon is not removed from the atmosphere, nevertheless, this process would be at the very beginning of the introduction of this process when the PAN fiber was initially not be produced in the required amounts from algae oils, but from fossil oil, a significant mitigation of greenhouse gas emissions due to the higher energy efficiency is associated with this new process, especially since already today the necessary total energy for building with carbon fiber and natural stone is approx 50% less than in building with steel and concrete, thus avoiding CO2 emissions already in the introduction phase of the new material (see, for example, EP 106 20 92). The increase in the total efficiency can comprise a factor of 4.