EP1490630A1

EP1490630A1 - Fuel combustion device

Info

Publication number: EP1490630A1
Application number: EP03714869A
Authority: EP
Inventors: Rolf Heiligers; Wolfgang Heinrich Hunck
Original assignee: Pyroplasma KG
Current assignee: Pyroplasma KG
Priority date: 2002-03-22
Filing date: 2003-03-21
Publication date: 2004-12-29
Anticipated expiration: 2023-03-21
Also published as: DE50304472D1; ATE335167T1; ES2272962T3; US20050208442A1; AU2003219092A1; EP1490630B1; WO2003081130A1

Abstract

The invention relates to a fuel combustion device (1) for the combustion of fuels in an exothermic chemical reaction, comprising a device (2) for supplying the fuels, a combustion chamber for combustion of the supplied fuels in a flame (10) and at least two electrodes (5, 9) through which an electrical field (E) is applied to the flame (10) with the purpose of producing a reaction plasma in said flame (10), wherein the reaction plasma produced has a high degree of ionization.

Description

description

Fuel combustion apparatus

The invention relates to a fuel combustion device for burning fuels in an exothermic chemical reaction.

Combustion is a chemical reaction (oxidation) of fuels with oxygen in the air, releasing heat. Hydrocarbons react to form carbon dioxide C0 ₂ and water vapor H ₂ 0. The combustion of solid fuels is initiated by heating to the ignition temperature, while the combustion of liquid fuels via intermediate gasification is caused by the ignition limit being exceeded by means of an ignition spark. In the case of gaseous fuels, combustion is induced by means of an ignition spark if the ignition limit is temporarily exceeded. Exhaust gases are generated during combustion. The quality of the combustion can be assessed from the composition of the exhaust gases. In the conventional sense, combustion is a plasmatic-looking exothermic redox reaction that takes place with the emission of electromagnetic radiation, such as light and heat radiation. In chemistry, oxidation is a chemical process in which a particle emits electrons. The emitted electrons are taken up by other particles, such as oxygen and chlorine atoms. This process is called reduction. Every oxidation process is coupled with a reduction process. The reactions on which such an electron transition is based are called redox reactions. Energy is involved in all chemical reactions. Higher energy systems are released into lower energy systems with the release of energy. Conversely, lower-energy systems are converted into higher-energy systems with the expenditure of energy. Will respond

Free heat energy, this is called an exothermic reaction. Conversely, if energy is absorbed, there is an endo- thermal reaction before. While some substances, for example charcoal only glow when burned, other fuels, such as wood, gasoline or gas, form a flame.

A candle flame shows three brightness zones. The flame contains a dark core inside, which is surrounded by a shining yellow coat. The shimmering yellow coat is usually surrounded by a blue flame border. The relatively cool core contains the unburned vapors of the solid material. Steam is generally the gas phase of a substance that is solid or liquid at room temperature. In the flame mantle, these vapors decompose into burning gases and fine carbon particles that get bright embers and emit light. These carbon particles only burn at the outermost edge of the flame if there is unhindered air access. The flame border forms the hottest part of the flame. A flame is thus a burning gas stream, the glow of the flame being caused by glowing solid particles. Flames therefore burn all combustible gases as well as those liquids and solids that are above the

Ignition temperature develop flammable vapors or gaseous decomposition products. Flames have a different electrical resistance on the flame jacket than the surrounding gas. The flame jacket is able to transport electrical charges. A conventional flame is a thermal ionization phenomenon that can be derived from Braun's molecular motion.

Flame ionization detectors (FID) use the ability of flames to transport electrical charges for flame monitoring. Ionization flame monitoring is based on the effect that the hot flame gases contain electrically charged atoms or molecules or ions that conduct an electrical current.

Figure 1 shows a flame ionization detector (FID) the state of the art. The flame ionization detector (FID) has a ring electrode R and a tip electrode S. The flame consisting of the flame core K and the flame jacket M is supplied with fuel. Between the RM electrode R, which surrounds the flame core K, and the tip electrode S, an alternating electrical field is built up in that an AC voltage is applied between the two electrodes by a voltage source. By applying the AC voltage to the tip electrode S immersed in the flame, a current can be measured by a current measuring device. Despite the AC voltage applied, the measured current is not an AC current, but a DC current. The ammeter can be used to determine whether a flame is burning. Due to the rectifier effect of the flame, the presence of a flame cannot be erroneously determined even in the event of an electrode short circuit. Flame ionization detectors FID can also be used to measure the concentration of hydrocarbons in the exhaust air and indoor air. The ionization of organically bound carbon atoms in a hydrogen flame is used as the measuring effect. The ion current occurring in the electric field is electrically amplified and displayed. The ion current is proportional to the number of organically bound carbon atoms present in the air sample. This gives the total carbon concentration in PPM. The detection limit is 0.1 - 0.2 PPM.

Figure 2a shows a plasma jet reactor according to the prior art. In the reactor shown, a gas mixture of N ₂ and 0 _{2 flows in} through a tube and enters a microwave field. A generator generates microwaves that feed into a waveguide and are reflected at the other end of the waveguide. The incoming and outgoing shaft are superimposed. The plasma jet reactor serves as an exhaust gas catalytic converter. Due to the dwell time of the flowing gas mixture of 0 ₂ and N ₂ in the overlay field of the microwaves, a thermal plasma is formed with peak temperatures of up to 10,000 Kelvin. If the microwave is pulsed, a cold plasma with a temperature of 1,000-2,000 Kelvin is created. The concentration of the pollutants contained in the exhaust gas is reduced by the plasma introduced into the reaction chamber.

Plasma is generally understood to mean an ionized gas or gas mixture. If energy is continuously supplied to these gases, for example in the form of electrical current, they change into a state in which neutral gas molecules are excited and when further energy is supplied, positively charged ions and negatively charged electrons are often produced. This mixture of neutral, positively and negatively charged particles is called plasma.

Another possibility of reducing the concentration of pollutants is to convert an easily ionizable noble gas, such as argon, as carrier gas by means of an electric field by means of microwaves into plasma.

Figure 2b shows an arrangement according to the prior art for the removal of pollutants. A microwave generator creates an electromagnetic field. The microwaves generated are reflected by a reflector and generate a plasma that hits the pollutant to be removed through an opening. The pollutant is, for example, dioxin. This greatly increases the Braun molecular motion of the dioxin molecules. The argon plasma removes the dioxin molecules due to the high temperature in a chemical reaction. A disadvantage of the arrangement shown in FIG. 2b is that the generator for generating the microwave has a very high energy consumption, typically requiring an output of 1-10 kW. In the arrangement shown in FIG. 2b, a plasma is first generated and then the generated plasma is brought into contact with the pollutant to be removed in a separate reaction chamber. The burning flame and the plasma field formed by the reflector are locally separated from one another. The efficiency of the arrangement for eliminating pollutants shown in FIG. 2b is very low due to the high energy requirement.

It is therefore the object of the present invention to provide a fuel combustion device for the combustion of fuels, in which the proportion of pollutants resulting from the combustion is minimized with little energy expenditure.

The solution to the problem according to the invention is to generate an alternating voltage which forms a potential difference, i.e. a voltage field in a flame whose voltage form allows a charge to flow from the cathode to the anode, for example a pulsed direct voltage or an alternating voltage superimposed on a direct voltage. A pure AC voltage is not functional and a pure DC voltage is only insufficiently functional to solve the problem according to the invention in a satisfactory manner.

The flame forms a dispersion spectrum with a flame resistance, which varies over the frequency range, with the alternating voltage which forms the potential difference.

This object is achieved according to the invention by a fuel combustion device with the features specified in claim 1.

The invention provides a fuel combustion device for burning fuels in an exothermic chemical reaction with a device for supplying the fuels, a combustion chamber for burning the supplied fuels in a flame, and with at least two electrodes through which an electric field is applied to the flame for generation a reaction plasma is applied in the flame, the reaction plasma generated having a high degree of ionization.

In the fuel combustion device according to the invention, an electric field is superimposed on the flame. The electric field creates a reaction plasma within the flame. This reaction plasma efficiently burns the supplied fuel so that the concentrations of the pollutants generated during the combustion are minimal.

The fuel combustion device according to the invention is characterized by an energy consumption which is below 100 watts for a 10 kW burner, i.e. the electrical energy input is only 0.1% of the total chemical energy input.

The supplied fuels are burned almost 100%, whereby undesired by-products in the exhaust gas, such as nitrogen oxides (NO _x ), are only released in very low concentrations.

When hydrocarbons are burned as fuel, the proportion of unburned hydrocarbons in the exhaust gas, which are also pollutants, in the exhaust gas is likewise reduced to a proportion of almost zero by means of the fuel combustion device according to the invention.

By forming a reaction plasma within the flame, the energy yield is compared to conventional ones

Incinerators significantly increased. The environmentally harmful toxins, such as dioxins and furans, are almost completely eliminated by the fuel combustion device according to the invention.

The reaction velocities within the flame are increased by the reaction plasma created in the flame and thus the combustion temperatures. The energy obtained in the combustion reaction carried out, the so-called reaction enthalpy, depends on how high the reaction rate is. The fuel combustion device, for example, hydrocarbon molecules

(C _X H _Y ) supplied as fuel. The more hydrocarbon molecules react with oxygen (0 ₂ ) per unit of time, the greater the energy generated by the fuel device. Generating the plasma increases the combustion temperature and thus the reaction rate.

However, this does not significantly increase the energy yield, since the energy gain from combustion is only the heat retention of the combustion gases that can be oxidized by the effect. The pollutant load is greatly reduced by the fuel combustion device according to the invention. Depending on the fuel, the fuel combustion device according to the invention can increase the energy yield by 1-3%.

The fuel combustion device according to the invention essentially has the following advantages:

The energy yield is increased in comparison to conventional fuel combustion devices;

The proportion of pollutants in the exhaust gases emitted is minimized. These pollutants can be nitrogen oxides or unburned hydrocarbons, for example.

Components of the fuel combustion device can be dimensioned smaller for the same output.

In addition, the noise emission can be reduced by about 10 decibels. Another advantage of the fuel combustion device according to the invention is that the shape of the flame can be influenced by the applied electrical field. In this way it can be achieved that the combustion flame generated fills the entire combustion chamber or, alternatively, certain spatial sections of the combustion chamber are reached by the flame.

The fuel combustion device according to the invention can be used in all devices in which an open fire or an open flame occurs. These are in particular:

Plants for generating steam and process heat in the

Industry; - heaters;

Gas turbines;

Mu11 power plants;

Jet engines;

High-temperature furnace; - internal combustion engines.

The essence of the invention is that an electric field is applied to the combustion flame to generate a reaction plasma in the flame. The electrical field is applied to the flame by means of at least two electrodes.

In a preferred embodiment of the fuel combustion device according to the invention, the electrodes are connected to a voltage generator.

The voltage generator preferably generates an AC voltage.

In a preferred embodiment, a transformer is provided for step-up transformation of the alternating voltage generated by the voltage generator, with a charge Statistical average shift occurs only in a charge transport direction hm.

The applied AC voltage can have different signal forms.

In a first embodiment, the AC voltage generated is almost sinusoidal, the positive half-waves having a larger amplitude than the negative half-waves or vice versa.

In an alternative embodiment, the alternating voltage generated is pulse-shaped, and there is also a half-wave deviation in the area of the voltage function between the positive and the negative half-function.

In a preferred embodiment, the voltage generator also generates a DC voltage in addition to the AC voltage. The AC voltage can be a pure sinusoidal AC voltage.

In this case, in addition to the alternating electrical field, an additional DC electrical field is superimposed on the combustion chamber.

The field strength of the electric field applied to the flame is preferably between 0.1 and 10 kV / cm.

In a preferred embodiment, the frequency of the electric field applied to the flame is between 50 Hz and 2 GHz.

The combustion chamber can be open or closed.

A combustion medium in which the flame is formed can also be located in the combustion chamber, for example a catalytic burner body or a pore burner body. In a first embodiment of the fuel combustion device according to the invention, the combustion chamber is an open space.

In an alternative embodiment, the combustion chamber is a closed combustion chamber.

In principle, the fuel supplied can be any fuel.

In a preferred embodiment, the fuel supplied is a gas mixture.

In a particularly preferred embodiment, the fuel gas mixture supplied is a hydrocarbon mixture.

An electric field is applied to the flame via at least two electrodes in order to generate a reaction plasma.

An electrical field for generating a reaction plasma is applied to the flame via at least two electrodes, between which, in one possible embodiment, there is at least one grid electrode for influencing vibrations.

An electrical DC field is created by the two electrodes. An electrical AC field is applied by the grid electrodes. This arrangement is equivalent to a tube arrangement, for example a triode or pentode.

The grid electrodes take on charge flow control within the flame combustion.

There can be a pure DC voltage between the anode and cathode if alternating-frequency control currents flow at the grid electrodes. At least one electrode preferably has an electrode tip for increasing the field strength of the electrical field.

The other electrode is preferably a ring electrode.

In a particularly preferred embodiment, the two electrodes form a capacitor with the flame, which is connected in an electrical resonant circuit, the flame itself forming an RC element.

In a preferred embodiment, waste materials, such as gauze, are burned by the flame in the closed combustion chamber of the fuel combustion device.

These waste materials form the fuel supplied.

In a preferred embodiment of the fuel combustion device according to the invention, the shape of the flame in the combustion chamber can be adjusted by changing the field strength and the frequency of the electric field E applied to the flame.

This offers the particular advantage that you can specifically reach certain rooms within the combustion chamber through the flame. The flame can be matched to the spatial dimensioning of the combustion chamber and the field strength and frequency of the applied electrical field preferably adjusted so that the combustion chamber is completely filled.

In a preferred embodiment, the fuel combustion device according to the invention has a mixing device for premixing the supplied fuels. In the fuel combustion device according to the invention, the ignition is preferably carried out by the application of the electrical field.

In an alternative embodiment of the fuel combustion device according to the invention, an additional ignition device is provided for igniting the supplied fuels. An ignition spark for triggering the combustion is generated by this ignition device.

In a particularly preferred embodiment of the fuel combustion device according to the invention, at least one of the two electrodes consists of a catalytically active material.

This catalytically active material is preferably platinum.

In a further preferred embodiment of the fuel combustion device according to the invention, one of the two electrodes is designed as an injector electrode, through which the fuels are sprayed into the combustion chamber or fogged by ultrasonic vibrations.

In a further preferred embodiment of the fuel combustion device according to the invention, one of the two electrodes is designed as a spray electrode.

The flame is preferably electrostatically charged by the spray electrode.

An alternating electromagnetic field can be coupled into this flame via an antenna system consisting of the ring electrode.

The invention also provides a method of burning fuels by flame in an exothermic chemical reaction, comprising the following steps, namely Supplying the fuels in a combustion chamber to generate the flame,

Applying an electric field to the flame to produce a reaction plasma with a high degree of ionization within the flame.

An alternating electrical field is preferably applied to the flame.

The alternating electrical field can also be coupled into the flame via a waveguide.

The alternating electrical field can be generated by a microwave generator.

In addition to the alternating electrical field, in an alternative embodiment of the method according to the invention, a constant electrical field is applied to the flame.

The field strengths of the electric field are preferably between 0.1 kV / cm and 10 kV / cm.

In the method according to the invention, the electric field is applied to the flame by at least two electrodes.

The field strength of the electrical alternating field superimposed on the direct voltage field is sinusoidal over time in a first embodiment.

In an alternative embodiment of the method according to the invention, the field strength of the alternating electric field is pulse-shaped over time.

The type of pulsing of a DC voltage is just as important as its pulse curve. The frequency and curve shape of an AC voltage superimposed on DC voltage is also important. If the pulse width decreases with a corresponding pulse edge rise of less than 500 ms or less from lKV / ns, solid fuels are further pulverized within the flame body. The pulse flank rise and the pulse width are a measure of the particulate comminution of solid fuels such as coal dust.

In the case of garbage incineration, this reduces the amount of dust and unbaked hydrocarbons adhering.

A high-frequency and high-voltage combustion reaction is very desirable, since a number of briefly and intensely developing plasma flame phenomena are formed, which lead to a short-term, intensive discharge within the flame. However, a balance of the energy input can be calculated via the flame resistance.

In a particularly advantageous development of the device according to the invention, the high-frequency field is operated in such a way that the plasma formed in the fuel-air mixture in the combustion chamber is thermally in equilibrium, although the energy input can only be pulsed. By regulating the high-frequency field of an electrically pulsed or alternating-field superimposed DC voltage field according to the invention it is achieved that a stationary plasma combustion and thereby a uniform plasma discharge of high intensity is formed, which has only a low tendency to discharge. Instead, because of the high frequency, it is achieved according to the invention that short-term, high-resistance plasma discharges form within the flame in the form of plasma flashes, which intensively produce energy for radicalizing the hydrocarbon-air mixture.

These plasma discharges only work for a short time, but because of their number in that adjacent to the electrode Area with the high potential differences particularly intense. This explains the low energy input into the flame.

In a particularly advantageous embodiment, the high-frequency field is operated at a frequency in the MHz range. Such a high frequency contributes to the formation of the homogeneously stationary plasma combustion which is in thermal equilibrium, during which compensation processes take place by discharges in the form of high-resistance plasma discharges and thus an intense flame reaction.

It is particularly advantageous if the plasma is generated by a high-frequency field with a steeply rising, pulse-shaped course, in which, in a further embodiment, the steeply rising pulse-shaped course is limited to values less than or equal to approximately 500 V / us. Such voltage curves favor the formation of high-resistance, only briefly burning plasma discharges within the flame.

In another development, the high-frequency field is regulated to an essentially sinusoidal curve, which can have a steeply rising curve in the region of the edges of the sine function.

It is particularly advantageous if the plasma discharge is formed from corona and / or streamer discharges on the electrode in order to establish reliable flame contact and to reduce electrode wear. In a further development, the plasma filaments can spread from the electrode in tufts diverging to the flame.

In an advantageous embodiment, the discharges form between a single electrode on the flame in the combustion chamber. This has the advantage that the geometry of the at least one electrode causes an increase in the field strength of the high-frequency field, which leads to the formation of short-term plasma discharges into the flame. Such a concentration of the effects of the high-frequency field on the flame allows the flame to be ignited safely and to be operated safely.

An electrode in the middle of the reaction space of the technical flame, which triggers a peak discharge by means of a Tesla transformer arrangement at the start of the reaction, makes sense in terms of construction.

The combustion capacity is a dynamic flame control factor and can be used as a control-dynamic flame optimization constant.

Flames are excited to oscillate at self-resonance at certain frequencies. The oscillation of the flame can be frequency controlled.

When two alternating voltages are applied to the flame, a difference frequency between the frequencies of the two alternating voltages arises according to the superimposition principle, which contributes significantly to avoiding flame breaks or the suppression of dynamic overshoots of the flames.

The frequency of the alternating electrical field is preferably between 50 Hz and 2 GHz.

In a preferred embodiment of the method according to the invention, the supplied fuels are ignited by applying the electric field, the exothermic chemical reaction being triggered. In an alternative embodiment of the method according to the invention, an ignition device is additionally provided, by means of which the supplied fuels are ignited.

In a particularly preferred embodiment of the method according to the invention, the fuels are first mixed stoichiometrically by a mixing device and then fed to the combustion chamber.

The fuels are preferably sprayed into the combustion chamber.

The invention also provides a low-emission internal combustion engine with a fuel supply device for supplying fuel, at least one combustion chamber for burning the supplied fuel in an explosion flame, each fuel chamber each having at least two electrodes through which an electric field is applied to the explosion flame to generate a reaction plasma can be created.

The combustion chamber is preferably formed by an engine cylinder and an engine piston movable therein for power transmission.

The first electrode of the internal combustion engine according to the invention is preferably a tip electrode.

The second electrode of the internal combustion engine according to the invention is preferably formed by the grounded engine cylinder.

In a preferred embodiment of the internal combustion engine according to the invention, the first electrode is connected to a direct voltage source. This DC voltage source is preferably connected in series to an oscillating circuit, which consists of a capacitor with an oscillating circuit coil.

A pulse signal is preferably coupled into this resonant circuit coil via a further coil.

The oscillation frequency of the oscillation circuit is preferably between 50 Hz and 2 GHz.

In a first embodiment of the internal combustion engine according to the invention, the internal combustion engine is a gasoline engine.

In an alternative embodiment of the internal combustion engine according to the invention, the internal combustion engine is a diesel engine.

In a preferred embodiment of the internal combustion engine according to the invention, the fuel supplied is ignited by the applied electric field to generate an explosion flame.

The invention also provides a waste incinerator for burning waste materials having a combustion chamber for burning the waste materials therein in a flame, and having at least two electrodes through which an electric field is applied to the flame to produce a reaction piasma.

In a first embodiment of the waste incineration device according to the invention, the combustion chamber is a rotary drum furnace.

The first electrode is preferably formed by a pointed electrode and the second electrode is preferably formed by a furnace jacket electrode. In a further embodiment of the waste incineration device according to the invention, the first electrode is formed by a needle electrode grid and the second electrode by a grate combustion grid.

In the preferred embodiment of the waste incineration device according to the invention, the combustion chamber has a first opening for supplying supply air and a second opening for extracting exhaust air.

The invention also provides a heating furnace for burning fuels in an exothermic chemical reaction with a device for supplying the fuels, a combustion chamber for burning the supplied fuels in a flame, and with at least two electrodes through which an electric field is applied to the flame Generation of a reaction plasma with a high degree of ionization can be applied, a medium being heated by the flame.

The medium is preferably the ambient air.

The heated medium is preferably fed to a heat exchanger.

Preferred embodiments of the fuel combustion device according to the invention, the method according to the invention for combusting fuels, the internal combustion engine according to the invention, and the inventive method are further described

Waste incinerator and the heating furnace according to the invention described with reference to the accompanying figures to explain the features of the invention.

Show it: 1 shows a flame ionization detector according to the prior art;

FIG. 2a shows a plasma jet generator according to the state of the art;

Figure 2b shows a pollutant catalyst according to the prior art;

FIG. 3 shows a first embodiment of the fuel device according to the invention;

4a shows a first embodiment of the masses in the erfindungsge ^¬ fuel combustion apparatus eingesetz- th tip electrode;

FIG. 4b shows a second embodiment of the tip electrode used in the fuel combustion device according to the invention;

FIG. 5 shows a second embodiment of the fuel combustion device according to the invention;

FIG. 6a shows a third embodiment of the fuel combustion device according to the invention;

FIG. 6b shows the third embodiment of the fuel combustion device according to the invention shown in FIG. 6a in a control loop;

FIG. 7 shows a fourth embodiment of the fuel combustion device according to the invention;

FIG. 8 shows an AC voltage applied to the electrodes according to an embodiment of the invention

Fuel combustion apparatus; FIG. 9 shows a further AC voltage signal applied to the electrodes in accordance with a further embodiment of the fuel combustion device according to the invention;

FIG. 10 shows a further voltage signal applied to the electrodes in accordance with a further embodiment of the fuel device according to the invention;

FIG. 11 shows a further AC voltage signal which is applied to the electrodes of the fuel combustion device according to the invention in accordance with a further embodiment;

FIG. 12 shows the arrangement of the fuel combustion device according to the invention in a resonant circuit;

FIG. 13 shows an equivalent circuit diagram of the resonant circuit shown in FIG. 12;

FIG. 14 shows a low-emission internal combustion engine according to the invention;

FIG. 15a shows a pulse signal which is coupled into the resonant circuit of the internal combustion engine according to the invention in accordance with FIG. 14;

FIG. 15b shows an AC voltage signal applied to the tip electrode of the internal combustion engine according to the invention in accordance with a preferred embodiment of the internal combustion engine according to FIG. 14;

FIG. 16 shows a first embodiment of the waste incineration device according to the invention;

FIG. 17 shows a second embodiment of the waste incineration device according to the invention; FIG. 3 shows the basic arrangement of the combustion device 1 according to the invention. The fuel combustion device 1 is used to burn fuels in an exothermic chemical reaction. The fuel combustion device 1 has a device 2 for supplying fuels. In the embodiment shown in FIG. 3, the fuels are a gas mixture. The gases to be burned are fed to a mixing device 3, which pre-mixes the gases to be burned by stochiometric means and delivers the fuel mixture via a gas line 2. The gas line 2 has an outlet opening 4 through which the gas mixture flows. A ring electrode 5 is arranged in a ring around the outlet opening 4 and connected to a voltage generator 7 via a line 6. The voltage generator 7 is connected to a tip electrode 9 via a line 8. By applying an electrical voltage U between the ring electrode 5 and the tip electrode 9, an electric field E is created in the open combustion space between the electrodes 5, 9.

The electric field E ignites the outflowing gas mixture, which burns in a combustion flame 10. The flame 10 has a flame core 10a and a flame jacket 10b. The flame 10 burns in a combustion chamber. In the embodiment shown in Figure 3, the combustion chamber is open. In an alternative embodiment, the combustion chamber is a closed combustion chamber. The electrical field E applied to the flame 10 generates a reaction plasma in the flame 10 that has a high degree of ionization. The AC voltage applied to the two electrodes 9, 5 preferably has a frequency f between 50 Hz and 2 GHz. The AC voltage can be sinusoidal or pulse-shaped. In addition, the voltage generator 7 preferably additionally generates a direct voltage, so that in addition to the alternating electrical field, a direct electrical field is also applied to the flame 10. The field strength of applied electric field E is preferably 0.1-10 kV / cm.

A charge-accelerated exothermic reaction takes place in the flame 10. The applied electric field E, which consists of a direct electric field and an alternating electric field, creates ions and electrons in the flame.

The most important reaction phases in the combustion process of redox-reactive exothermic reactions are thermal radicalization, cracking and the redox-reactive fire reaction. The thermal radicalization and the plasma formation is intensified by the applied electric field E. The radicals formed maintain their energy state until a redox reaction partner triggers the chemical redox reaction. The reaction time of the redox reaction decreases with the increasing degree of radicalization of the redox reaction partners. As a result, the exothermic temperature gradient increases. The temperature within the flame 10 and thus the combustion efficiency n are also increased.

The supplied fuel molecules are thermally cracked. The applied electric field E accelerates the bringing together of the radicalized and ionized redox reaction partners, so that the reaction speed increases sharply. The electrochemical equilibrium of the combustion reaction is shifted by the electric field E. The static, electrodynamic and combustion kinetic parameters are changed. The burn-up times are reduced. The reaction plasma of the flame has a very high degree of ionization I. The flame resistance R of the plasma generated is lower than the electrical resistance of an ordinary flame. The degree of ionization I that occurs within the plasma depends on the frequency, the slope and the pulse ratio of the applied AC voltage U. The alternating electric field is designed with respect to the field strength and the frequency such that the degree of ionization I within the flame is optimal. As the degree of ionization I increases, the amount of pollutants decreases because the fuels burn completely. However, the degree of ionization I must not be increased too much so that too much electrical energy supplied is not lost as heat. The ratio of the starting products of the chemical redox reaction to one another can be influenced by setting the field strength and the frequency of the applied electric field E. If, for example, two substances A, B react to the starting products C, D, the ratio f of the starting products C, D can be influenced by the frequency f and the field strength of the electric field E applied to the flame 10. With the fuel device 1 according to the invention, it is therefore possible to specifically reduce the proportion of harmful fuel products.

FIGS. 4A, 4B show different embodiments of the tip electrode 9 within the fuel device 1 according to the invention. The tip electrodes 9a and 9b compress the field lines and thus locally increase the field strength. In the embodiment of the tip electrode 9a shown in FIG. 4A, a wire 11a with a diameter of 1/10 to 1/100 mm is accommodated in a jacket 12a. The casing 12a consists of an insulation material or a ceramic, such as quartz. This wire 11a is connected to the voltage generator 7 via the line 8. At the end of the lead wire 11a there is a ball 13a, the diameter of which is larger than the diameter of the wire 11a. The wire 11a conventionally consists of a tungsten-steel alloy. The bullet 13a also consists of a tungsten steel alloy before ignition. After ignition, a layer of tungsten carbite is formed in the ball 13a, which is resistant to high temperatures.

FIG. 4B shows an alternative embodiment of the tip electrode 9. In the embodiment shown in FIG. 4B, the tip electrode 9b has a conical tip 13b. Due to the conical tip 13b, a particularly high field strength density is achieved.

FIG. 5 shows a further embodiment of the fuel combustion device 1 according to the invention. In the embodiment shown in FIG. 5, a transformer 14 is additionally provided, which contains a first coil 14a and a second coil 14b. The alternating voltage generated by the voltage source 7 is stepped up by the transformer 14 in accordance with the turns ratio of the two coils 14a, 14b. The highly transformed alternating voltage is applied via lines 6, 8 to the two electrodes 5, 9 to generate an alternating electrical field. The embodiment shown in FIG. 5 enables particularly high electrical field strengths to be achieved.

FIG. 6A shows a third embodiment of the fuel combustion device 1 according to the invention. In the embodiment shown in FIG. 6A, the counter electrode 9 is not formed by a tip electrode, but by a counter electrode 9, which surrounds a glass cylinder made of insulation material. The cylinder 15, which consists of an insulating material, is coated with the counter electrode 9. The interior of the cylinder 15 forms the combustion chamber for the flame 10. The cylinder 15 is preferably a quartz tube. The flame 10 absorbs electrical charge via the quartz 15 so that a capacitive reactive current can flow due to the alternating electrical field. If a DC voltage is additionally applied to the electrodes 5 and 9 by the voltage generator 7, a small DC current additionally flows.

FIG. 6B shows the third embodiment of the fuel combustion device 1 according to the invention shown in FIG. 6A in a control loop. The flame 10 burns the supplied gas mixture and emits exhaust gases upwards to an exhaust gas detector 16. The exhaust gas detector 16 detects the chemical composition of the exhaust gas and detects the proportion of pollutants, for example the proportion of nitrogen oxide within the exhaust gas. The exhaust gas detector 16 supplies data to a controller 18 via a data line 17, the data supplied indicating the proportion of the pollutants to be eliminated in the exhaust gas. The controller 18 controls the amplitude (U) and the frequency f of the voltage U generated by the voltage generator 7 via control lines 19. As a result, the amplitude | u | and the frequency f of the electric field E applied to the flame 10 is set. The arrangement shown in FIG. 6B represents a control circuit 20, with the aid of which the pollutant content of the exhaust gases, which are caused by the combustion flame 10, can be minimized. For this purpose, the controller 8 changes the frequency and the amplitude of the voltage until a minimal pollutant content is detected by the exhaust gas detector 16. The control shown in FIG. 6B enables particularly environmentally friendly heating furnaces to be implemented. The generation of the plasma within the flame 10 minimizes the amount of pollutants. The frequency f and the amplitude of the applied electric field E are regulated in such a way that the concentration of the emitted pollutants is minimal. In a preferred one In the embodiment, the controller 18 is programmable for various fuel gas mixtures supplied by the mixer 3.

FIG. 7 shows a fourth embodiment of the fuel combustion device 1 according to the invention. In the embodiment shown in FIG. 7, the counter electrode is formed by the earth or mass. The advantage of the embodiment shown in FIG. 7 is that a counter or tip electrode does not have to be provided.

FIGS. 8 to 11 show different signal profiles of the voltage U applied to the electrodes 5, 9. The voltage profile shown in FIG. 8 is a sinusoidal AC voltage which is superimposed on a DC voltage Un. The ratio of the amplitude of the AC voltage is | 0 | to the DC voltage Uo, preferably about one, as shown in FIG. 9.

FIG. 10 shows a further possible signal form of the applied AC voltage signal, the rising signal edge being steeper than the falling signal edge. The AC voltage signal applied is pulse-shaped. The rising signal edge has an edge steepness of 2 kV / ms, for example. This allows particularly high ionization gradients to be achieved within the flame.

FIG. 11 shows a further variant of an AC voltage signal applied to the electrodes 5, 9. The AC voltage signal shown in FIG. 11 is pulse-shaped. The pulse ratio, which results from the ratio between the duration of the pulse Δtpuis and the pulse repetition time Δt _Pau se, is preferably about 1/3. With increasing duration of the created Voltage pulses decrease the resistance R of the flame asymptotically against a resistance R ₀ . The slope of the voltage pulses is, for example, 2 kV / ms. Typical amplitudes of the voltage pulses are 8 kV. When the pulsed AC voltage is applied, the flame oscillates harmoniously.

Figure 12 shows the position shown in Figure 6A third Ausfuh ^¬ approximate shape of the inventive Brennstoffverbrennungsvor- device 1 in a resonant circuit. The voltage U generated by the voltage generator 7 is applied to the secondary circuit via a capacitor 21 and a transformer 22, which consists of two coupled coils 22a, 22b. The ring electrode 5 is connected to the secondary coil 22b via a line 23. The counter electrode 9 is connected via a line 24 to a DC voltage source 25. The flame jacket 10b of the flame 10 forms a counter electrode to the cylindrical electrode 9. The flame jacket 10b forms a capacitor surface. Energy is coupled in via the resonant circuit. The secondary resonant circuit consists of the coupling inductor 22b and a capacitor. This capacitor is formed by the counter electrode jacket 9, the flame jacket 10b and the air dielectric.

FIG. 13 shows the equivalent circuit diagram for the resonant circuit shown in FIG. 12. The electrode 9 and the flame jacket 10b form a capacitor 26 to which the flame resistor 27 is connected in parallel. A DC bias of 1 to 10 KV is applied by the DC voltage source 25. The resonance circuit stabilizes the flame in terms of its shape and its burning behavior. The secondary resonant circuit is an RCL resonant circuit. The resonant circuit has a resonance frequency f _R. The Flame can act from a half-open resonant circuit or as CLOSED ^¬ sener resonant circuit. The flame 10 acts as an open resonance circuit or as an antenna, the flame body itself acting as an energy absorber.

Figure 14 is a preferred embodiment of a harmful ^¬-lean combustion engine according to the invention. The internal combustion engine has a fuel supply device, not shown, for supplying fuel. The fuel is fed into a closed combustion chamber 28 as a combustion chamber. The combustion chamber 28 is formed by an engine cylinder 29 and an engine piston 20 movable therein, which is provided for power transmission. A tip electrode 9 projects into the combustion chamber 28. Preferred embodiments of such a tip electrode 9 are shown in FIGS. 4A, 4B. The piston 30 is movable up to a top dead center TDC within the engine cylinder 29. The tip electrode 9 extends into the combustion chamber 28 up to a distance L1. The distance between the top of the combustion chamber and top dead center OT is L2. In a preferred embodiment, the distance Ll is greater than the difference between L2 and Ll. As soon as the piston 30 has reached the top dead center OT, a voltage pulse is coupled into the resonant circuit coil 31b via a transformer 31, which comprises two coils 31a, 31b. A capacitor 32 is connected in parallel to the oscillating circuit coil 31b. A DC voltage source 32 is connected in series between the tip electrode 9 and the oscillating circuit coil 31b. The counter electrode to the tip electrode 9 is preferably formed by the grounded motor cylinder 29. The voltage signal shown in FIG. 15b is present at the tip electrode 9. The ^voltage U 1 is coupled into the oscillating circuit coil 31 ^b by the transformer 31, so that the oscillating circuit consisting of the capacitor 32 and the coil 31 begins to oscillate. The generated vibration is damped, so that its amplitude decreases. The amplitude of the pulse-shaped voltage generated by the voltage generator is, for example, 2 KV. The intervals between the different voltage pulses of the voltage signal Ul is determined by the number of revolutions of the motor. The oscillating circuit 31b, 32 applies an oscillating, decaying sinusoidal alternating voltage signal to the tip electrode 9, to which a direct voltage Un is superimposed. The voltage signal thus formed is shown in Figure 15B. The fuel mixture supplied to the combustion chamber is ignited by the first pulse of a voltage pulse sequence. The plasma formed in the explosion flame is maintained by the subsequent voltage pulses of the pulse sequence. The ignition preferably takes place shortly before the piston 30 has reached the top dead center TDC. The internal combustion engine according to the invention, as shown in FIG. 14, does not require an independent ignition device. This can optionally be provided in addition. The internal combustion engine according to the invention is a gasoline engine or a diesel engine. The frequency f of the voltage pulses generated by the oscillating circuit 31b, 32 can be in a range between 50 Hz and 2 GHz. The internal combustion engine shown in Figure 14 according to the invention is characterized by a particularly simple structure. A conventional spark plug is not required for ignition. The ignition takes place through the tip electrode 9. By generating the plasma within the explosion flame, the combustion within the combustion chamber 28 takes place particularly effectively with a high efficiency. ciency. The proportion of pollutants formed is particularly low due to the plasma formed in the explosion flame.

FIG. 16 shows a first embodiment of a waste incineration device 33 according to the invention. The waste incineration device 33, as shown in FIG. 16, has a combustion chamber 34, which in the embodiment shown in FIG. 16 is a rotary drum furnace 34. The rotary drum furnace 34 is continuously rotated by roller drives 36, 37. The waste material 38 to be incinerated is located on the bottom of the rotary drum oven 34. The waste material 38 is introduced through an opening within the rotary drum oven 34. A tip electrode 9 projects into the rotary drum furnace 34. The tip electrode 9 is connected to the voltage generator 7 via a line 8. The voltage generator 7 generates an AC voltage and a DC voltage. The generated voltage is applied to a furnace jacket electrode 39 via a line 6. The generated voltage U for garbage combustion is between 30 and 45 kV, for example.

As a result, such a strong electric field E is generated within the combustion chamber 34 that the waste material 38 contained therein begins to burn. The waste material 38 burns in a flame 10 which contains a reaction plasma. Typical combustion temperatures are 800 ° C to 900 ° C.

FIG. 17 shows an alternative embodiment of a waste incineration device 33. In this embodiment, the first electrode is formed by a needle electrode grid 40 and the second electrode by a grate combustion grid, ie by an insulated mesh band 41. The combustion Room 34 has a first opening 42 for supplying supply air and a second opening 43 for extracting exhaust air.

The combustion device 1 according to the invention, as shown in FIG. 3, is also suitable for the construction of

Heater. The flame 10 heats the ambient air as an energy transmission medium. The ambient air is then fed to a heat exchanger.

Claims

Patent claims

1. Fuel combustion device (1) for burning fuels in an exothermic chemical reaction with:

(a) a device (2) for supplying the fuel;

(b) a combustion chamber for burning the fuel supplied to a flame (10);

(c) and with at least two electrodes (5, 9), through which an electric field (E) is applied to the flame (10) to generate a reaction plasma in the flame (10), the reaction plasma generated having a high degree of ionization having.

2. Fuel combustion device according to claim 1, characterized in that the electrodes (5, 9) are connected to a voltage generator (7).

3. Fuel combustion device according to claim 2, so that the voltage generator (7) generates an alternating voltage.

4. Fuel combustion device according to claim 3, characterized in that a transformer (14) is provided for step-up transformation of the alternating voltage generated by the voltage generator (7).

5. Fuel combustion device according to claim 3, characterized in that the alternating voltage generated is almost sinusoidal, ^where there is a difference in the surface of the voltage function between the positive and the negative half-wave.

6. Fuel combustion device according to claim 3, characterized in that a generated alternating voltage is in pulse form.

7. Fuel combustion device according to claim 2, characterized in that the voltage generator (7) generates a direct voltage.

8. Fuel combustion device according to claim 1, characterized in that the field strength of the electric field (E) applied to the flame (10) is between 0.1 and 10 kV/cm.

9. Fuel combustion device according to claim 1, characterized in that the frequency (f) of the electrical field (E) applied to the flame (10) is between 50 Hz and 2 GHz.

10. Fuel combustion device according to claim 1, characterized in that the combustion chamber is a closed combustion chamber.

11. Fuel combustion device according to claim 1, characterized in that the combustion chamber is an open space.

12. Fuel combustion device according to claim 1, characterized in that that the fuel supplied is a gas mixture.

13. Fuel combustion device according to claim 12, characterized in that the supplied fuels are a hydrocarbon mixture.

14. Fuel combustion device according to claim 1, characterized in that at least one electrode (9) has an electrode tip for increasing the field strength of the electric field (E).

15. Fuel combustion device according to claim 1, characterized in that at least one electrode (5) is a ring electrode.

16. Fuel combustion device according to claim 1, characterized in that the electrodes (5, 9) form a capacitor which is connected in an electrical resonant circuit.

17. Fuel combustion device according to claim 10, characterized in that waste materials are burned by the flame in the closed combustion chamber.

18. Fuel combustion device according to claim 1, so that the shape of the flame in the combustion chamber can be adjusted by changing the field strength and the frequency (f) of the electric field (E) applied to the flame (10).

19. Fuel combustion device according to claim 1, characterized in that a mixing device (3) for pre-mixing the supplied

Fuels are provided.

20. Fuel combustion device according to claim 1, characterized in that an ignition device for igniting the ^fuel supplied is provided.

21. Fuel combustion device according to claim 1, characterized in that at least one of the electrodes (5, 9) consists of a catalytically active material.

22. Fuel combustion device according to claim 21, characterized in that the catalytically active material is platinum.

23. Fuel combustion device according to claim 1, characterized in that one of the electrodes (5, 9) is a spray electrode through which the fuels can be sprayed into the combustion chamber.

24. Fuel combustion device according to claim 23, characterized in that the flame (10) can be electrostatically charged by the spray electrode.

25. Method for burning fuels by a

Flame in an exothermic chemical reaction with the following steps: (a) supplying the fuels to a combustion chamber to generate the flame (10);

(b) applying an electric field (E) to the flame (10) to generate a reaction plasma with a high degree of ionization within the flame.

26. The method according to claim 1, characterized in that an alternating electric field is applied to the flame (10).

27. The method according to claim 26, so that in addition to the alternating electric field, a constant electric field is applied to the flame (10).

28. Method according to one of the preceding claims 25 to 27, so that the field strength of the electric field (5) is between 0.1 kV/cm and 10 kV/cm.

29. The method according to claim 1, characterized in that the electric field (5) is applied to the flame (10) by at least two electrodes (5, 9).

30. The method according to claim 26, characterized in that the field strength of the alternating electric field (E) is sinusoidal over time.

31. The method according to claim 26, so that the field strength of the alternating electric field (E) is pulse-shaped over time.

32. The method according to claim 26, so that the frequency (f) of the alternating electric field (E) is between 50 Hz and 2 GHz.

33. The method according to claim 25, so that the supplied fuels are ignited by applying the electric field (E), whereby the exothermic chemical reaction is triggered.

34. The method according to claim 25, so that the fuel supplied is ignited by an ignition device provided.

35. The method according to claim 25, characterized in that the fuels are mixed stoichiometrically by a mixing device (3) and then fed to the combustion chamber.

36. The method according to claim 25, so that the fuels are sprayed into the combustion chamber.

37. Low-emission combustion engine with: (a) a fuel supply device for supplying fuel;

(b) at least one combustion chamber (28) for burning the supplied fuel in an explosive flame;

(c) wherein each combustion chamber (28) has at least two electrodes (5, 9) through which an electric field (E) can be applied to the explosion flame to generate a reaction plasma.

38. Internal combustion engine according to claim 37, so that the combustion chamber (28) is formed by an engine cylinder (29) and a movable engine piston (30) for power transmission.

39. Internal combustion engine according to claim 37, characterized in that a first electrode (9) is a tip electrode.

40. Internal combustion engine according to claim 37, characterized in that a second electrode (29) is formed by a grounded engine cylinder.

41. Internal combustion engine according to claim 37, characterized in that the first electrode (9) is connected to a direct voltage source (32).

42. Internal combustion engine according to claim 41, characterized in that the DC voltage source (32) is connected in series to an oscillating circuit (31b, 32) which consists of a capacitor (32) and an oscillating circuit coil (31b).

43. Internal combustion engine according to claim 42, characterized in that a pulse signal is fed into the via a further coil (31a).

Oscillating circuit coil (31b) is coupled in.

44. Internal combustion engine according to claim 42, so that the vibration frequency (f) of the resonant circuit (31a, 32) is between 50 Hz and 2 GHz.

45. Internal combustion engine according to claim 37, so that the internal combustion engine is a gasoline engine.

46. Internal combustion engine according to claim 37, so that the internal combustion engine is a diesel engine.

47. Internal combustion engine according to claim 37, so that the supplied fuel is ignited by the applied electric field to generate the explosion flame.

48. Waste incineration device (33) for burning waste materials with: (a) a combustion chamber (34) for burning the waste materials (38) therein with a flame (10);

(b) and with at least two electrodes (9, 39; 40, 41) through which an electric field (E) can be applied to the flame (10) to generate a reaction plasma.

9. Waste incineration device according to claim 48, characterized in that the combustion chamber is a rotary drum furnace.

50. Waste incineration device according to claim 49, characterized in that a first electrode (9) is formed by a tip electrode and a second electrode (39) is formed by a furnace jacket electrode.

51. Waste incineration device according to claim 48, characterized in that a first electrode (40) is formed by a needle electrode grid and a second electrode (41) is formed by a grate combustion grid.

52. Waste incineration device according to claim 48, characterized in that the combustion chamber (42) has a first opening for supplying supply air and a second opening (43) for discharging exhaust air.

53. Heating furnace for burning fuel in an exothermic chemical reaction with: (a) a device (2) for supplying the fuel;

(b) a combustion chamber for burning the fuel supplied in a flame (10);

(c) and with at least two electrodes (5, 9) through which an electric field (E) can be applied to the flame (10) to generate a reaction plasma with a high degree of ionization, a medium being heated by the flame (10). .

54. Heating oven according to claim 39, so that the medium is the ambient air.

55. Heating oven according to claim 40, so that the heated medium is fed to a heat exchanger.