SE432245B - SET TO MAKE CARBON MONOXIDE FROM CARBON Dioxide AND DEVICE FOR EXECUTION OF THE SET - Google Patents

Description

7'8.062; 04-9 10 15 20 25 30 35 2 of an organic heat carrier with a small particle size of 0.1-2 mm (see Journal of The Japan Petroleum Institute, vol 18 (ll), 2, (1975)). However, even in this new process, the necessary energy is supplied with combustion heat from reactions between coal powder and supplied air, as shown in equations (2) - (4), and also through the combustion heat from combustion of added fuel, so that the apparatus for CO generation is necessarily complicated. Furthermore, the primarily obtained gas mixture contains hydrogen (H2), which is difficult to eliminate during the subsequent purification.

As mentioned above and as also shown in the table below, the processes hitherto known, all of which use incinerators or gas-forming furnaces, require complicated apparatus and result in the production of raw gas mixtures containing H2 and methane (CH4), which are difficult to eliminate.

Type of gas- The composition of the gas mixture generated (vols formation furnace co H2 C02 CH4 Ng Generator (air) 30 5 8 - 55 Generator (oxygen) 90-95 2 - - 5 -7 Water gas generator 40 45 - 51 4 -5 0, 5 - 1.0 4 - 9 winklemgn 42 37 _ 1s' 0.9 11 Complete Lurgí- 17.4 42.0 30.2 9.4 0.5 carburettor Complete Koppers-Totzek 54.2 33.6 10.5 0.1 1.2 carburetor Kenichiro BANDO: Journal of The Japan Petroleum Institute, vol 18, (ll), 5, (1975).

Contrary to what has been stated above, the present invention is carried out using an electric discharge reaction, i.e. by the energy created in an electric discharge field, according to the equation: CO 2: in CO + å 02, whereby CO is produced directly from CO2.

As a result, the apparatus for carrying out the process is very simple and the primary gas mixture obtained does not contain significant amounts of nitrogen, hydrogen or hydrocarbon gases, as is the case with the prior art gas-forming furnaces and which is difficult to eliminate. Thus, it can be stated that the present invention provides a completely new way of producing CO.

The invention uses a reaction chamber, such as an electric furnace, which is equipped with at least one cathode and anode pair. Both electrodes are tubular and made of such conductive materials as carbon, iron or copper. An opening of the tubular cathode is arranged at a distance suitable for an electric discharge so that it faces an opening of the tubular anode. The reaction is carried out by successive discharges at the gap between the openings of the two tubular electrodes. or a combination of CO and carbon powder, is introduced into the chamber, in particular to the gap between the Raw Material, i.e. the CO openings of the two tubular electrodes, through one or both of the tubes forming the electrodes. Since the discharge takes place at the actual gap between the inlet openings of the material, the gap is enclosed by the flame curtain formed by the sparks due to the successive discharges. By enclosing the material supplied to the gap itself by the flame curtain from the sparks, intimate contact between the material and the flames is ensured and the material decomposes due to the high energy present in the discharge field. In other words, the supplied material cannot come out of the reaction system without passing the flame curtain, so that the spark energy is used efficiently for the intended CO 2 formation reaction.

Another object of the invention is to provide practical means for substantially improving the above-mentioned efficiency. In this case, each of the tubular electrodes in the above-mentioned system is equipped coaxially with a toroidal or disc-shaped flange, which is made of the same material as the electrode, at the opening or close to the same.

The circular flange extends concentrically outward from the tubular electrode and faces the similarly shaped flange of the other electrode. When the reaction 7.8 Û 6204-- 9 10 15 20 25 30 35 4 4 is carried out with this device, electrical discharges occur not only between the two openings but also between the flange of the cathode and the flange of the anode. The CO2 material introduced through the opening on the tubular electrode is brought into contact with multiple spark discharge curtains, which occur between the two flanges and between the two electrode openings. The starting material is thus subjected to a very efficient decomposition reaction.

In the drawings, the figures illustrate the device according to the present invention. Fig. 1 shows the first embodiment and Fig. 2 shows the second embodiment.

The reference numerals used are: 1 reaction chamber; 2, 3 tubular electrodes (main electrodes); 4, 5 openings; 6, 7 flanges; and 2a tubular intermediate electrode.

A practical example of the invention is described in the following with reference to the drawing. As shown in Fig. 1, the tubular electrodes 2 and 3 are placed in the reaction chamber 1 so that the openings 4 and 5 of the two electrodes face each other and form a gap therebetween.

A disc-shaped flange 6 or 7 is arranged on the outer periphery of each electrode at or near the opening 4 and 5, respectively. The reaction chamber 1 is constructed with double walls 8 and a cooling medium, such as water, flows in the space 9 between the walls. The coolant is introduced through the supply line 10 and flows out through the outlet line 11, so that the reaction gas mixture is cooled and so that overheating of the reaction chamber due to the heat generated from the discharges is also avoided.

Both electrodes 2 and 3 are electrically insulated from the walls 8 with insulators 12 and 13. A high voltage sufficient to generate discharges is applied between the electrodes 2 and 3 by means of an electrical circuit which includes connection terminals 14 and 15 'for supply. of energy, a reactor 16, a transformer 17 and a capacitor 18. The charge of the capacitor is discharged successively for repeated discharges not only between the openings 4 and 5 of the electrodes 2 and 3, respectively, but also between the opposite surfaces of the flanges 6. and 7. In the figure, 19 10 15 20 25 30 7 7806204-9 5 and 20 denote the end socket of the transformer and 21 and 22 the connection points to the electrodes.

The CO2 starting material, which is contained in a container (not shown), is fed through a pipe to the tubular electrodes 2 and 3 and discharged into the discharge gap between the openings 4 and 5. The electrodes are constantly cooled by the stream of CO2 gas flowing inside the tubes. so that there are no such problems with the electrodes as softening, distortion or melting. The coz flows are fed to the two opposite openings and flow out into the discharge gap, where the two flows meet each other and give rise to a turbulent flow.

In this turbulent state, the CO2 gas is exposed to a radiation of sparks, ie electron beams with high energy, and is at least partially ionized. In this ionized atmosphere, which is caused by the turbulent gas currents, the electron beams (sparks) extend from one electrode to the other in a number of zigzag lines just like lightning. The electron beam discharges cover the gap between the openings 4 and 5 and also the space between the flanges 6 and 7 and this space and the gap is enclosed by the drawn-out blue sparks, which form a so-called "flame curtain". The flame curtain itself, on the one hand, prevents the scattering of the electron beams extending along the ionized gas particles, and on the other hand also reduces unwanted diffusion of the gases involved in the reaction, so that the discharge reaction takes place efficiently. The CO2 gas supplied from the openings cannot flow out of the reaction system without passing through the flame curtain, and the decomposition reaction takes place efficiently when the CO2 gas breaks through the flame curtain. The resulting gas mixture is allowed to flow out through the outlet line 23. The closed hole 24 is intended for cleaning the inside of the reaction chamber.

Another example of the invention will be explained with reference to Fig. 2. As shown in Fig. 2, a tubular intermediate electrode 2a is arranged between the tubular main electrodes 2 and 3. The intermediate electrode is usually of the same material and has the same diameter as the main electrodes. Both 7É fi62fl4 ~ 9 10 15 20 25 30 35 6 the openings 4a and 5a of the intermediate electrode 2a are placed so that they face the openings 4 and 5, respectively, and near the two openings are flanges 6a and 7a, respectively, which face the flanges 6 and 5 of the main electrodes. The CO2 material is also supplied from the openings 4a and 5a of the intermediate electrode 2a through a wire 26. The wire 26 is electrically insulated with an insulator 27 from the double wall 3 other elements in Fig. 2 and their mode of operation is the same as in Fig. 1. place the intermediate electrode between the main electrodes, the discharge takes place in the spaces between 4 - 4a, 5 - Sa, 6 - 6a or 7 ~ 7a, so that the space for the discharge reaction can be expanded. This means that insertion of the intermediate electrode according to Fig. 2 is useful for utilizing the electrical energy for the decomposition reaction of CO 2 more efficiently. Furthermore, since it allows the supply of the Cqf material from itself, the resulting CO generation per unit time can be increased.

Experimental results Example (fig) 1 (fig 1) 2 (fig 2) Primary voltage 200 V 7 200 V Transformer 10 kV / 200 V 10 kV / 200 V Capacitor capacitance 0.05 PF 0.05 FF Electrodes (tubular coil inside 5 mm 5 mm Diameter '{outside 10 mm 10 mm Gap between the openings 15 mm 15 mm Distance between opening and flange 30 mm 30 mm Flange diameter 25 mm 25 mm Flange thickness 7 mm 7 mm coz flow velocity 3.6 m3 / n 13.5 m3 / h Consumed electrical energy 0.9 kWh l, l kWh C0 production 0.15 m3 / h 0.21 m3 / h Energy efficiency *) 58.2 s 66.7% x) The energy efficiency refers to the percentage ratio between the energy consumed for CO the generation, calculated according to equation (4) above, and the total consumed electrical energy. When comparing the results in experiments 1 and 2, it appears that the use of an intermediate electrode and an increase in the discharge space results in an increase in the CO generation and also in an increase in the energy efficiency from 58.7. % to 66.7%.

From the experimental results above it is clear that the present invention provides a completely new way of producing CO from CO 2 by efficiently utilizing energy from electrical discharges. As the necessary energy source for the CO-generating reaction according to equation (1), the hitherto known methods rely on the combustion reactions according to equations (2) - (4), so the known methods require much more complicated operation and equipment. In contrast, it is now possible according to the present invention to produce CO with a high energy efficiency and to produce a CO gas which is substantially free of such gases as H2, N2 and hydrocarbons, which are difficult to separate from CO when present together therewith. It also means a great advantage in utilizing resources that one can utilize the industrial CO2 exhaust gases which are present in abundant quantity, as a carbon source of chemical reactions of many kinds by converting CO 2 to CO according to the present invention.

Claims (5)

7-806204-9 10 15 20 25 30 35 PATENT CLAIMS A method of producing carbon monoxide from carbon dioxide, characterized in that: a) CO 2 -containing gas is introduced into an airtight reaction chamber (1) through tubular electrodes (2, 2a, 3), each electrode tube extending from outside to the inside of the reaction chamber through the walls (8) of the reaction chamber and wherein the orifices (4, 4a, 5, 5a) of the tubular electrodes in the reaction chamber face each other with a distance between the orifices suitable for electric discharge. b) that successive electrical discharges are generated between the electrodes, and c) that the resulting CO-containing gas mixture is collected and discharged from the reaction chamber (1). 2. A method according to claim 1, characterized in that each of the tubular electrodes (2, 2a, 3) has a coaxially arranged, disc-shaped flange (6, Ga, 7, 7a) in the vicinity of the electrode orifice (4, 4a , 5, Sa). 3. A method according to claim 2, characterized in that at least one tubular intermediate electrode (2a) is placed between the tubular main electrodes (2, 3), the respective orifices (4a, 5a) of the intermediate electrodes facing the orifices (4, 4) of the main electrodes. 5), and the tubular intermediate electrode has a coaxially arranged, disc-shaped flange (6a, 7a) near each of the two orifices. 4. A method according to claim 3, characterized in that the CO 2 -containing gas is also introduced into the reaction chamber through the two orifices (4a, 5a) of the tubular intermediate electrode from a line (26) outside the reaction chamber. An apparatus for producing carbon monoxide from carbon dioxide according to any one of the preceding claims, characterized in that it comprises a) b) C) å) 9) 7806204-9 q 'an airtight reaction chamber (1), at least one pair of tubular electrodes (2, 2a, 3) extending from the outside to the inside of the reaction chamber through the walls (8) of the reaction chamber, the orifices (4, 4a, 5, 5a) of the tubular electrodes in the reaction chamber facing each other and arranged at a distance suitable for electrical discharges therebetween, means (16-18) for generating successive electrical discharges between the electrodes, means for introducing CO 2 -containing gas through the tubular electrodes (2, Za, 3) to the reaction chamber (1), and means (23) for collecting the resulting gas mixture outside the reaction chamber.