WO2002028771A1

WO2002028771A1 - Method and apparatus for plasma-catalytic conversion of fossil fuels into a hydrogen-rich gas

Info

Publication number: WO2002028771A1
Application number: PCT/ES2000/000380
Authority: WO
Inventors: Fateev Vladimir; Boris Potapkin; Victor K. Jivotov; Ricardo Blach Vizoso
Original assignee: David Systems Technology, S.L.
Priority date: 2000-10-05
Filing date: 2000-10-05
Publication date: 2002-04-11
Also published as: AU2000277905A1

Abstract

The method involves pre-heating the raw materials, fuel and water, which have been previously evaporated in corresponding evaporators (EC, EA) and the air coming from the corresponding feeder (AA) in a heat exchanger (IC). From said exchanger, the materials are fed into an input chamber (CE), then to a mixing chamber (CM) and finally to a plasma-catalytic reactor (RQ) assisted by a microwave generator (GM). The corresponding synthesis gas (GS) that is used as heat source in the heat exchanger (IC) is obtained from the plasma-catalytic reactor in which the plasma acts as catalyst accelerating the conversion of fossil fuel into synthesis gas.

Description

METHOD AND APPARATUS FOR CONVERSION

PLASMACATALÍTICA DE FOSSIL FUELS IN A

GAS RICO IN HYDROGEN

D E S C R I P C I Ó N

OBJECT OF THE INVENTION

The invention relates to an apparatus and a method for plasmacatalytic conversion of fossil fuels into a hydrogen rich gas. The method allows to carry out the vapor-air / fossil fuel or air / fossil fuel conversion reactions. The air is preheated, a part of the fossil fuel is burned in the combustion chamber, the waste is mixed with the combustion products and, optionally, with water vapor, and the heated reagents are introduced into the plasmacatalytic reactor where the plasma acts as a catalyst accelerating the process of fossil fuel conversion.

The method object of the invention, in comparison with other known methods of converting fossil fuels into hydrogen-rich gas, achieves greater conversion of the fossil fuel, improves the composition of the gas mixture produced as a result of the process and improves energy efficiency .

BACKGROUND OF THE INVENTION

According to all the analyzes of specialists in the sector, hydrogen is considered as the fuel that will be used in the 21st century.

In the use of the fuel cell, the main problem The question is how to get hydrogen to fuel the fuel cells. Currently, a high-tech fuel cell needs 1 m ³ / h of hydrogen to produce 1 Kwh. The only viable technical-economic way for the use of fuel cells will involve having a chemical mini-factory, called a fuel reformer or converter, to convert fossil fuels or alcohols into hydrogen-rich gas (with processes such as conversion- steam reform, partial oxidation, auto-thermal conversion-reform, catalytic pyrolysis, etc,).

There are four "critical variables" that determine the commercial use of the converter in a car:

- the first is "how quickly the converter can be started up": the most efficient converter today takes about 5 minutes to warm up;

- the second is "the transient response": how long does it take a car to respond when the driver steps on the accelerator; a gasoline engine responds in thousandths of a second, but a converter that reacts slowly makes the car's responses to the driver's demands slow so the drivers would reject it;

- the third is that the "thermal and electrical energy consumption" necessary to meet the needs of the converter process, are very small and are within parameters that allow it to be covered with part of the energy generated by the internal combustion engine or fuel cell that uses the converter; Y

- If the converters could be perfected, then the last obstacle to solve would be the "cost of the reformer".

In 1992, Arthur D. Little initiated a program, in conjunction with a DOE study, to develop additional options for conversion to Methanol board as a means of hydrogen supply for fuel cell vehicles. Phase 1 of this program included an analysis of the poly fuel converters, hydrogen on-board storage technologies and the requirements of the hydrogen infrastructure. Phase 2 will involve the development and testing of a 10 Kw converter and a 1 kg capacity hydrogen storage unit.

Alternatives to the direct supply of hydrogen to the fuel cell include liquid hydrogen or compressed hydrogen tanks, carbon absorption and hydride storage.

Liquid hydrogen has been tested in various vehicles since the 1970s in the United States and other countries. The weighted volumetric density of liquid hydrogen, when used with the fuel cell, is the same or better than that of diesel fuel used with an internal combustion engine. Its drawbacks include high energy for liquefaction, handling problems and the inevitable release of boiling gas.

Compressed hydrogen on board is the simplest technology to conceptualize and could benefit from the recent advances in composite materials and cost improvements derived from the progress in vehicles powered by natural gas. High pressure tanks constructed of advanced materials could provide reasonable performance, but only marginal volumetric performance. Technical issues pending resolution include cylinder permeability, standards for tank design for higher pressures and hydrogen compressor design for refueling.

Several companies are developing poly fuel processors, with different processes, such as: Steam reforming SR: This process basically represents a catalytic conversion of methane and water (steam) into hydrogen and carbon dioxide, through three main stages. Numerous companies, namely Haldor-Topsoe (USA-Denmark), Howe-Baker Engineers (USA), IFI / ONSI (USA), Ballard Power Systems (Canada) and Chiyoida (Japan) have worked on the design and construction of this system.

Partial oxidation (PO): it is an exothermic process whereby hydrogen and carbon dioxide are produced from hydrocarbon fuels (gasoline and others) and oxygen (or air). PO processes have a number of advantages over SR processes. Companies such as Arthur D. Little (EPYX), Chrysler Corp. and Hydrogen Burner Technologies (all of them from the US) have announced plans for the development of PO converters. The stages of the EPYX PO cell fuel converter include (1) vaporization of the fuel (gasoline) by the application of heat; (2) the vaporized fuel is combined with a small amount of air in the partial oxidation reactor, producing hydrogen and carbon monoxide; (3) the vapor on the carbon monoxide reacts with a catalyst to convert most of the carbon monoxide and carbon dioxide and additional hydrogen; (4) In the preferential oxidation stage, the injected air reacts with the remaining carbon monoxide on the catalyst to form carbon dioxide and water vapor, leaving hydrogen rich gases.

Autothermal conversion (AR): In this exothermic process, the hydrocarbon fuel reacts with a mixture of water and oxygen. The energy released by the hydrocarbon oxidation reaction drives the steam conversion process. Companies like Rolls-Royce / Johnson-

Matthey (United Kingdom) and International Fuel Cell / ONSI (USA) are working on the development of the AR process.

Thermal decomposition (TD) (or pyrolysis, cracking) of hydrocarbon fuel: hydrogen and clean carbon are produced in this process. The energy demand per mole of hydrogen produced from methane is somewhat lower than for the SR process. The technical-economic evaluation of hydrogen production by SR, PO and TD processes indicates that the cost (in US $ / 1000 m ³ ) of hydrogen produced by TD (US $ 57) is lower than for the processes of SR (US $ 67) and PO (US $ 109).

Plasma catalysis: is another process of conversion of hydrocarbons helped by plasma; in this process cold non-thermal plasma is used as a source of an active species, in order to accelerate chemical reactions. The energy requirements of the process can be satisfied, in this case, through thermal energy (low temperature), so that the plasma acts as a catalyst. DAVID SYSTEMS AND TECNOLOGY S.L. He is working on this line and has developed a plasmacatalytic fuel converter.

Plasma can be produced through the action of very high temperators, strong electric fields or powerful magnetic fields. In a discharge, free electrons gain energy from an imposed electric field and lose it through collisions. The discharge plasma is characterized by high electron temperators and low gas temperature, having electron concentrations of approximately 109 to 1012 cm ³ and absence of thermal equilibrium, which makes possible a plasma in which the gas temperature is close at room temperature, to obtain a plasma in which electrons are sufficiently energized to cause the breakage of molecular bonds. In the case of MPCR the molecular bonds of the gas mixture (water + gasoline + air) producing synthetic fuel (hydrogen and carbon monoxide).

It has been observed that a wide spectrum of reactions takes place in plasmas, including reactions between electrons and molecules, ions and molecules, ions and ions, and electrons and ions. In the past twenty years, different types of downloads have been available. The availability of radio frequency and microwave generators has focused attention, in recent years, on the use of electrode-free discharges.

In cold non-thermal plasma, only charged particles (electrons, ions) gain energy from the applied electric field, while neutral particles remain almost at room temperature. Cold non-thermal plasma can be created by an electric shock normally operated at reduced pressure. Discharge plasmas are very suitable for the promotion of chemical reactions in which thermally sensitive materials participate.

The electrical energy necessary to maintain the plasma state can be transmitted to the discharge gas either by resistive coupling with internal electrodes, by capacitive coupling with external electrodes or by inductive coupling with an external coil, or, in the case of microwave discharge , by means of a slow wave structure. Due to the many reactive species in a plasma, it has not been possible to fully explain the mechanisms of chemical reactions in a plasma.

The reformers produce a synthetic gas formed mainly of hydrogen and carbon monoxide, but to be able to use said synthetic gas in a fuel cell it is necessary remove synthetic gas components mixed with hydrogen.

DESCRIPTION OF THE INVENTION

In the method proposed by the invention, reactions are carried out between the hydrocarbons present in the fossil fuel and air, or between said hydrocarbons, water vapor and air, said process comprising the following operational phases:

0 - Preheat the air.

Incinerate part of the fossil fuel, which results in reaction products and waste. Mixing said waste with the combustion products and, optionally with water vapor, whereby a reaction mixture is obtained.

Bring said reaction mixture into a plasmacatalytic reactor where the plasma acts as a catalyst accelerating the conversion of fossil fuel into syn-gas.

o The specific details of said process are specified both in the detailed description of the invention and in the claims.

The invention also concerns the apparatus for the implementation of said method, apparatus in which a fuel evaporator, a water evaporator and an air feeder are involved, which supply the respective materials, through a heat exchanger, specifically the air and part of the fuel from an inlet chamber and the water and the rest of the fuel to a mixing chamber, which also receives the materials or coming from the inlet chamber, said mixing chamber being fed to a chemical reactor assisted by a microwave generator, for the obtaining the synthesis gas (syn-gas).

DESCRIPTION OF THE DRAWINGS

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical implementation thereof, a set of drawings is attached as an integral part of said description. In an illustrative and non-limiting manner, the following has been represented:

Figure 1 shows the scheme of an apparatus (in the form of blocks) provided by this invention.

Figure 2 shows the diagram of the pre-chamber and mixing chamber of an apparatus provided by this invention.

Figure 3 shows the scheme of the chemical mixing reactor of an apparatus provided by this invention.

Figure 4 shows the reactor scheme based on a quasi-stationary microwave discharge.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a method for plasmacatalytic conversion of a fossil fuel (MF) into synthetic gas (syn-gas), in which reactions are carried out between the hydrocarbons present in said

MF and air or between said hydrocarbons, water vapor and air, comprising: preheating the air; incinerate part of the MF with which reaction products and residues are obtained; mixing said wastes with the combustion products and, optionally, with water vapor, whereby a reaction mixture is obtained; and bringing said reaction mixture into a plasmacatalytic reactor where the plasma acts as a catalyst accelerating the conversion of MF into syn-gas.

In a particular embodiment, the plasmachemical acceleration of conversion of the MF into syn-gas is carried out either by passing the reaction mixture through periodic pulse discharge plasma in a continuous pseudocoron effect arrester at atmospheric pressure, or by passing the mixture of reaction through quasi-stationary torch discharge plasma with a radiation pulse length of less than 100 milliseconds (ms).

In the plasmacatalytic chemical reactor the chemical reaction of conversion of the MF into syn-gas takes place by means of a periodic microwave discharge of impulses on the preheated gas previously. The chemical transformation of the gas mixture from the mixing chamber that is introduced into the chemical reactor is converted into a mixture of carbon monoxide and hydrogen carrying energy after microwave discharge on the preheated gas previously. In said plasmacatalytic chemical reactor a subcritical value of microwave pulse electric field strength is established, a discharge of microwave pseudocoron injectors is initiated at the edges of the crown elements, and at the heads of the microwave injectors establishes an electric field equal to or greater than 1,000 kV / cm. The establishment of this high electric field allows microwave injectors to propagate for a period of time not exceeding 1 μs practically up to the reactor walls, branching into space simultaneously and filling the entire cross section of a chemical reactor practically completely.

The microwave energy source generates the pulse set with a pulse duration between 0.1 and 1 microseconds (μs) and a pulse period to pulse duration ratio between 100 and 1,000 in a microwave radiation range included within the X and S bands (decimeters and centimeters), with specific impulse power, which provide the necessary level of electric field in the resonator and in the heads of the continuous microwave dischargers.

In general, a total reagent flow rate (Q) and a specific average power (W) should be selected from the following considerations: to perform the specific plasma catalysis process with plasma energy input of 0.05- 0.2 kWh / m ³ , so that the plasma input value does not exceed 10% of the enthalpy value of the reagent at the working temperature.

In a particular embodiment, the plasma-catalytic conversion of the MF into syn-gas is carried out by reaction between the hydrocarbons present in said MF, water vapor and air, and the reactant temperators of the inlet of the plasmacatalytic reactor are comprised between 800 K and 15,000 K. In this case, the ratio between the incinerated part of the MF and its residue is preferably between 0.5 and 2, and the water / air molar ratio will be appropriate.

In another particular embodiment, the plasma-catalytic conversion of the MF into syn-gas is carried out by reaction between the hydrocarbons present in said MF and air, and the temperatures of the reagents at the plasmacatalytic reactor inlet are between 600 K and 1,100 K. In this case, the ratio between the incinerated part of the MF and its residue is preferably between 0.4 and 2, and the air / MF molar ratio at the inlet The plasmacatalytic reactor is between 16 and 20.

The invention also provides an apparatus for plasmacatalytic conversion of a fossil fuel (MF) into a synthetic gas (syn-gas) comprising an air heater and a plasma-catalytic chemical reactor implemented said reactor as a cylindrical microwave resonator for the Hll wave type and microwave energy source within the range of wavelengths of the X and S bands, which is connected to the reactor and excites within the resonator a periodic pulse discharge in a continuous pseudocoron effect arrester with a duration of the pulse between 0.1 and 1 μs and a pulse-to-pulse period duration between 100 and 1,000, and a combustion chamber is located between the air heater and the reactor-resonator along the line of air flow, said combustion chamber having 2 different inputs for the autonomous entry of the incinerated part of the MF and its residue, optionally mixed or with water vapor, in different areas of the combustion chamber.

In a particular embodiment, microwave radiation from the generator to the microwave resonator is performed either with the help of a rectangular waveguide along the axis of the resonator or with the help of a rectangular waveguide through a lateral side of the resonator, in both cases being located in a cylindrical resonator an excitation node of wave type Hll between the waveguide and the resonator, which includes an coupling element for the resonator-waveguide connection. This resonator coupling element with the waveguide is designed so that its value provides a subcritical value of the intensity of Electric microwave field for a specific diameter of the chemical resonator reactor.

The reflectors at the rear end of the microwave resonator may overlap with the comical elements for the reagent entry and removal of the reaction products, or alternatively, a reflector at the rear end of the microwave resonator may overlap with the conical element. for reagent entry and removal of reaction products and another reflector from the rear end of the microwave resonator io overlaps the Hll wave type excitation node in the cylindrical waveguide.

In a particular embodiment, the longitudinal axis of the rectangular waveguide is located at a distance of a few lengths of

15 half wave of radiation in the cylindrical waveguide with Hll wave type from a rear end reflector; the diameter of the cylindrical resonator is selected from the wave type excitation condition Hll in the waveguide; and the length of the resonator is equal to an integer number of half-wavelengths of radiation in a waveguide

2nd cylindrical with wave of type Hl 1.

The microwave discharge of the continuous pseudocoron unloader is initiated in the microwave resonator through a set of metal edges inserted into the resonator in the area of

25 maximum electric field. The location of the edge of each rod is selected on the condition that, at the edges of each rod and on the heads of the microwave arresters, there is an electric field equal to or greater than 1,000 kV / cm.

The apparatus provided by this invention further comprises

(i) a combustion chamber that, in a particular embodiment, includes 2 series systems of concentric supersonic injectors, connected separately with the reagent inlets and located along the gas flow line, and (ii) a heater implements, for example, as a heat recovery ñitercambiador.

In a particular embodiment of this invention, whose scheme is shown in Figure 1, an apparatus for plasmacatalytic conversion of fossil fuels is provided in a hydrogen-rich gas comprising a pre-chamber, a mixing chamber, an energy input microwave, a plasma-catalytic chemical reactor, a heat exchanger, a fossil fuel evaporator, a water evaporator, and an air supply.

Said apparatus operates in the manner described below. Fossil fuel and water vapor from the corresponding evaporators and the air from a compressor by means of thermally insulated pipes flow to a heat exchanger, where they are additionally heated by the heat of synthesis gas (syn-gas ) leaving the chemical reactor. A part of the fossil fuel vapor (approximately 25% of the total) and all the air feed the pre-chamber where a mixture of carbon dioxide and water vapor is formed at a high temperature, usually between 2,200 K and 2,400 K when the Fossil fuel burns. The resulting mixture flows into the mixing chamber where it is mixed with water vapor and the rest of the fossil fuel (approximately 75% of the total) from the heat exchanger through injectors. After mixing, a gas is formed with a temperature normally between 1,200 K and 1,400 K flowing to the chemical reactor. The reaction of the conversion of the mixture into syn-gas is carried out in the chemical reactor under the action of a periodic discharge of microwave pulse. Next, the syn-gas flows to the heat exchanger and transfers the heat to the fossil fuel, water and air, which feed the pre-chamber and mixing chamber.

The pre-chamber is intended to burn a part of the fossil fuel to reach an elevated temperature of the gas that feeds the mixing chamber. The mixing chamber serves to create a gas flow with a very defined temperature and reagent concentration, optimal for the catalysis plasma reaction, this objective is achieved by mixing a certain amount of gas from the pre-chamber with a certain amount of fossil fuel and water vapor.

The purpose of the microwave energy input is the emission of microwave energy, supplying said energy to the chemical reactor, and comprises a modulator, a microwave generator, a waveguide system and a unit for the input of microwave energy to the chemical reactor. The modulator produces a sequence of periodic voltage pulses that are necessary for the operation of the microwave generator. In a particular embodiment, said microwave generator is of the magnetron type. The waveguide system provides microwave radiation to the device.

The chemical reaction of the conversion of the fossil fuel into a hydrogen-rich gas takes place in the chemical reactor by means of a periodic microwave discharge of impulses on the preheated gas. The chemical transformation of the gas mixture from the mixing chamber that is introduced into the chemical reactor is converted into a mixture of carbon monoxide and hydrogen carrying energy after microwave discharge on the preheated gas previously.

The heat exchanger is responsible for the heat recovery of the fossil fuel input syn-gas and the water and air vapor that It feeds the pre-chamber and mixing chamber and also condenses the unreacted water vapor and fossil fuel to trap the coal dust that can form in the reactor. The maximum temperature of the syn-gas at the heat exchanger inlet is 1,200 K, while the temperature of the syn-gas at the heat exchanger outlet is below 100-C.

The fossil fuel evaporator is responsible for evaporating the liquid fossil fuel, while the water evaporator is responsible for evaporating the water. The air is supplied to the device through the air supply.

Specifically, the device consists of the following components:

- An input chamber block (CE).

- A mixing chamber block (CM).

- A microwave energy input block (GM).

- A chemical reactor block (RQ).

- A block of the heat exchanger (IC). - A block of the fuel evaporator (EC).

- A block of the water evaporator (EA).

- An air supply block (AA).

A main scheme of the device is shown in Figure 1. The device works as follows. Fuel and water vapor from the corresponding evaporators and compressor air will flow through thermally insulated pipes into the heat exchanger. In this part they will be heated further, recovering the heat of the synthesis gas that emanates from the chemical reactor. A part of the fuel vapor (25% of the total consumption) and all the air will be fed into the inlet chamber. When he burns Fuel will form the mixture of carbon dioxide and high temperature water vapor (2200 to 2400 Kelvin). This mixture flows into the mixing chamber. Water vapor and a large part (75%) of the heat exchanger fuel will flow into the mixing chamber, through the injectors. Once the mixture has been made, a gas will be formed at a temperature of 1200-1400 Kelvin, which flows into the chemical reactor block. The reaction of the conversion of the mixture into a synthesis gas is carried out in the chemical reactor, under the action of a periodic microwave pulse discharge. Next, the synthesis gas flows into the heat exchanger, transferring its heat to the liquid fuel, water and air, which feed the inlet and mixing chambers.

Description of the invention with an example of a device with the following technical specifications:

Productivity: up to 17 nanometers ³ of hydrogen gas per hour.

Dimensions and weight of the reactor that includes the inlet and mixing chambers:

length: 35 cm diameter: 10 cm weight: 10 kg

Conversion procedure: partial oxidation and partial steam-assisted oxidation.

Composition of the synthesis gas at the PMPCR output: hydrogen + CO and

C0 ₂ + N ₂ (from air) + / C ₄

Percentage of hydrogen in the synthesis gas: not less than 55%.

Percentage of the mixture of 0 ₂ + C0 ₂ + alkanes. less than 2% Fuel consumption, water vapor and air for the production of 1 nanometer ³ of synthesis gas: fuel consumption: 0.288 kg water vapor consumption: 0.108 kg air consumption: 1.018 kg total energy consumption (electrical and thermal): less than 1 kilowatt hour per 1 nanometer ³ of synthesis gas. Electric power consumption: less than 0.1 kilowatt hour per 1 nanometer ³ of synthesis gas.

The inlet chamber (CE) block is designed to burn a portion of fuel, so that it reaches the high temperature of a gas, located beyond the mixing chamber. The mixing chamber block is designed to create a gas flow rate with a high concentration of defined reagents and temperature, appropriate to carry out the catalytic reaction of the plasma. This will be achieved by mixing a certain amount of a gas that flows from the inlet chamber, with fuel and water vapor.

Fuel vapor flows from the heat exchanger (IC) into the inlet chamber (CE) at a temperature of 340 ° C and with a consumption of 1,050 kg hour. The air flows from the heat exchanger into the inlet chamber at a temperature of 400 ° C and consumes 15,265 kg hours. Fuel and air jets are injected into the inlet chamber through individual injectors (I) (see Figure 2). The mixture of fuel and air, whose quantity measured in jets corresponds to the following stoichiometric equation: 6.81C _n H ₂₂ +112.40 ₂ + 414N ₂ = 74.93C0 ₂ + 74.93H ₂ 0-r-414N ₂ (1), will result in the combustion of fuel and the formation of carbon dioxide and water at a temperature of 2320 ° Kelvin. The above forms a gas flow whose composition is calculated as follows: C0 ₂ - 13.29%; H ₂ 0 - 13.29%; N ₂ - 73.42%, with a consumption of 16,002 kg hour. The additional flow rate of this hot gas is fed to the mixing chamber (CM) (see Figure 2). The fuel vapor will flow from the heat exchanger to the interior of the mixing chamber at a temperature of 340 ° C and with a consumption of 3,270 kg hour. Water vapor will flow from the heat exchanger to the interior of the mixing chamber at a temperature of 400 ° C and with a consumption of 1,620 kg hour. In the mixing chamber, the fuel and water jets are injected radially through injectors. The following gas mixture is formed after agitatingly mixing these jets with a hot gas (calculated as follows): C _n H ₂₂ - 3.15%; H ₂ 0 - 24.43%; C0 ₂ - 11.10%; N ₂ - 61.32%. The temperature of this gas mixture is 1730 ° Kelvin.

The distribution of the fuel and air jets in the inlet chamber (CE) has been described with the help of a semi-empirical proportion proposed in [1], for turbulent jets of free flow. According to the experimental measurements and the theoretical proportions summarized in [1], the length of an initial position of the undisturbed core of a turbulent jet is determined by the expression:

The distance from the injectors to a certain region of an expanded turbulent jet, provided with the concentration L already established, is associated with the size of the intersection of the jet D, by the following proportion [1]

L = (1.7-2.3) D (4).

Therefore, to reduce the length of the mixer it is necessary to reduce the diameter of its channel. However, to make the above possible until the value L is equal to the length of an initial region of the nucleus not disturbed from a jet (so that the gas concentration is uniform in the section of the channel), therefore, the minimum diameter of the mixer would have N injectors

5 D _sm = N ⁰ ' ⁵ * (2.5-3.5) d, (5).

In this way, the distance over which the gas is to be mixed is determined by the expression (3). The minimum number of injectors, which are uniformly located on an end face of the channel of the mixer (see Figure 2) in which a turbulent mixing of various components of mixed substances will be performed through the following jets, is determined by the expression (5).

The numerical calculations were performed assuming that the diameter of the mixer has been provided and that it is equal to D _m = 3sm, and the diameter of the injector should not be less than 0, lmm (d,> 0, lmm), for avoid contamination of the injector channel driven through it by substances. The speed of the gas in the injector was determined by means of the expression:

25 in which Q is the total gas consumption (in g / s), n is the gas concentration, (μm / N _A ) the weight of a molecule (N _A - avocado number). It follows from the formulas mentioned above that for the injectors whose diameters are equal to 0, lmm, 0.2mm, 0.3mm, 0.4mm, the following quantities of injectors N, of distances L, will be given in the

3 or that there will be a mixture of gas, and the speed of the gas in the injector U.

N 90 22 10 6

L (sm) 1.2 2.4 3.6 4.8

U (sm / sec) 5000 1250 555 312

It is known that the best mixture is provided by injecting the jets of a gas component in cross flow with another component in the flow. In this way, there are two mechanisms for organizing the mixing procedure. In operation (2) the mixing is carried out so that the jets, in interaction with a flow rate and between themselves, uniformly fill the section of the mixing chamber (principle of umform distribution of the jets: considering here that the depth of penetration of a jet into a downward flow rate should constitute a quarter of the diameter of the jet). In the other mechanism (3), the mixture is considered to be more effective with the intensive impact of the jets on each other (it is the principle of the jets that collide intensely, here the depth of penetration of the jets in a downward flow rate should not be less than the mixer radius). To calculate the parameters of the mixing chamber by the principle of uniform distribution of the jets, the following proportion (2) was used:

H = 0.25D _mixer, H / d ₂ = 2,2q ⁰ ^'5, q = _{Vl Pl} ² / p ₂ ² (7).

Wherein, H is the depth of penetration of a jet in a downward flow rate; pyv constitute the density and velocity of the gas, indices 1 and 2 refer to the radially injected jets and the hot gas emanating from the injection chamber; d ₂ is a diameter of the injector. Being the diameters of the mixer and injector related to the proportion:

Q = l, 3.10 - ^2. (D _mixer / d ₂₎ ² (8). The numerical calculation shows that:

d ₂ = nezclador ¡^ (9).

That is, the diameter of the injector should be 17 times smaller than the diameter of the mixing chamber. In case the diameter of the displacement chamber is equal to 3sm, then the diameters of the injectors should be equal to 0.17sm.

To calculate the mixture organized under the principle of intense collision of the jets, the following proportion was used:

Z _> 0.5D _mixer , za / d ₂ = 0.335 a = 0.07 (10).

Where, z is the length of the undisturbed core of a jet, then the diameters of the mixer and the meter are related by:

Mixer ^ 0d ₂ (11).

Thus, when mixing by the principle of intensive collision of the jets, the diameter of the jet should be about 10 times smaller than the diameter of the mixture.

In this way, the calculations made under the formula (6) will allow to determine the number of injectors necessary to radially inject the fuel, air and water.

-'- 'fuel ⁼ - ^. ^ water = J, 1 ^ water ⁼ - ^ "

The microwave power input block (GM) is designed for the emission of energy from microwaves, to supply it to the Prototype and to introduce it into the reactor, and consists of a modulator, a microwave generator, a waveguide system and a unit for microwave energy input inside the prototype reactor.

The modulator produces a sequence of periodic voltage pulses, which are necessary for the operation of the microwave generator. The microwave generator is of the magnetron type. The waveguide system supplies the microwave radiation to the Prototype.

Since the electric power consumption or _the same is 0.1 kilowatt hours per 1 nanometer ³ of synthesis gas and the productivity of Prototype Q = 17 nanometers ³ of hydrogen gas hour, consequently, the average power of the microwave generator W _average is:

- _nedf a = ε _the * Q = 1.7 kilowatts

The investigation of the catalytic effect of plasma has established that the duration of the radiation p must be between 0.5-1 μs. In this way, the pulse power W _imp is:

_imp = W _average lτ = 1.7 Megawatts

There is a microwave system that meets the above requirements. It is known by the name of "Buton". The "Buton" system parameters are shown below:

Microwave radiation parameters:

radiation frequency: 2.9 Gigaherzios; radiation pulse duration: 0.5-1 μs; impulse repetition: up to lKiloherzio; pulse power: 1.7 Megawatts; average power: 1.7 Kilowatts; radiation wavelength: 10 sm.

The chemical plasma reactor (RQ) is designed to favor the chemical reaction by the action of a periodic impulse microwave discharge on a previously heated gas.

The chemical transformation of the gas mixture, which flows from the mixing chamber and enters the chemical reactor through the carrier of energy CO and H ₂ , was carried out after the effect produced by the discharge of microwaves onto the gas previously heated. In this way, the total reaction of the procedure carried out in the chemical chamber will be described by means of the following stoichiometric equation:

21.24C _n H ₂₂ + 74.93C0 ₂ + 414N ₂ + 164.93H ₂ 0 = 308CO + 398.7 H ₂ +

414N ₂ (2)

Form the mixture of the following composition: H ₂ - 33.2%; CO -

26.2%; N ₂ - 38.5%; CH ₄ - 0,2%; C0 ₂ - 0.2%; H ₂ 0-0.35%; C ^ - 0.7% at a temperature of 1170 ° Kelvin and with a gas consumption of 32,366 kg hour. In this way, the Prototype produces 25 nanometers ³ of synthesis gas hour of the compound: H ₂ - 55, 33%; CO - 44.67%.

To calculate the diameter of the chemical reactor. The Prototype uses the "Buton" microwave generation system, whose frequency is v = 2.9 Gigaherz. The vacuum wavelength Ü ₀ for this frequency is: λ ₀ = c / v = 103 mm (c = 2.99 * 10 ⁸ m / s - speed of light in a vacuum). For the lowest generation method H _n , the critical wavelength λ _cr and the critical diameter of the waveguide D _cr and λ ₀ are comprised in the proportion:

λ _cr = λ ₀ ; λ _cr = 3.41 * D _cr / 2.

Thus allowing to determine the D _cr : D _cr = 60.4 mm.

For the following method of or ₀₁ , the critical wavelength λ _cr * is: λ _cr = 2.6 * D _cr 72.

Therefore, the critical diameter of the waveguide D _c is: D _C1 * = 79.2 mm.

The diameter of the chemical reactor D should allow the propagation of the wave of type H _n and will be beyond the interruption of the wave of type E ₀₁ : D _cr <D <D _c .

The diameter of the chemical reactor D = 75 mm was selected. The critical wavelength for this diameter is the same as: λ _cl = 3.41 * D / 2 = 127.87 mm.

The wavelength of the waveguide Ü is:

Λ = λ ₀ / (l - (λ ₀ / λ _cr ) ² ) ^& - 174.2 mm.

The scheme of the chemical reactor is shown in Figure 3. The reactor is a spherical waveguide with a diameter of 75 mm, being joined by an airtight unit, on the side of the microwave generator (GM), and on the opposite side, by a metallic piston. Drills (T) (2-3 mm diameter) are drilled in the metal piston (PM) to visualize the discharge. The hermetic unit is designed to prevent a hot gas from the chemical reactor from entering the 5-wave guide system. The hermetic unit (AH) consists of a quartz plate, which is installed perpendicular to the waveguides. The quartz plate vacuum isolates the reactor chamber from the waveguide system. The tightness must withstand heating up to 600 ° C. The waveguide system (from the magnetron to the quartz plate) is pressurized by an SF gas in order to prevent microwave interruption.

The output of the mixing chamber is coupled to the spherical waveguide, such that its axes are perpendicular to each other. A pointed tungsten needle (1-2 mm in diameter) is used to start the microwave discharge. The needle is inserted into the chemical reactor (RQ), perpendicular to the waveguide, to the mixing chamber through the hole (T ') in the waveguide wall. The tungsten needle can move in the direction of its axis.

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The thermocouple is used to measure the temperature in the chemical reactor. It is inserted through the hole, which is located in a diametrically opposite manner, to the hole for the tungsten needle. The thermocouple is removed from the waveguide, at the moment the discharge of the

25 microwaves in the chemical reactor. The range of measured temperators will range from 300 to 300 ° C.

The heat exchanger (IC) block is designed so that it can recover heat from the inlet synthesis gas, from steam

30 of fuel and water and air that feed the inlet and mixing chambers, as well as to condense water vapor and non-fuel reactants, to trap carbon dust that may form in the chemical reactor. The maximum temperature of the synthesis gas at the heat exchanger inlet is 1200 ° Kelvin, while the temperature of the synthesis gas at the heat exchanger outlet is less than 100 ° C. The heat exchanger maintains continuous operation for 1 hour (between the purge of the liquid). The heat exchanger consists of a chamber that is coupled to the wall of the spherical waveguide, so that its axes are perpendicular to each other. The axes of the heat exchanger and the chemical reactor are the same. The heat exchanger contains hollow stainless nozzles, which are located parallel to the axis of said heat exchanger. The fuel and water vapors from the fuel and water evaporators and the air from the air supply block flow into the heat exchanger and the stainless nozzles, in a manner opposite to the flow of the synthesis gas Emanating from the chemical reactor. The fuel vapor is heated in the heat exchanger, from a temperature of 170 ° C to 400 ° C. In this previous procedure, a power of 660 watts of the synthesis gas is obtained. After passing through the heat exchanger, one part of the fuel vapor flows into the inlet chamber, and the other part flows into the mixing chamber.

The water vapor is heated in the heat exchanger, from a temperature of 100 ° C to reach 300 ° C, thus allowing to recover my power of 170 watts, after the water vapor of the heat exchanger flows into The mixing chamber.

The air is heated in the heat exchanger, from a temperature of 20 ° C to reach 400 ° C, obtaining a power of 1700 watts from the synthesis gas, after the heat exchanger air flows into the chamber input The synthesis gas transfers a power of 5000 watts to the heat exchanger, when it is cooled from 1200 Kelvin to 300 Kelvin. In this way, the heat exchanger performance will not be less than 50%.

The fuel evaporation block (EC) is designed for the evaporation of a liquid fuel and can be running continuously for 1 hour (between filling). The volume of the fuel evaporator is 8 liters. The fuel vapor consumption is 4.3 kg hour. The output fuel vapor temperara is 180 ° C. The electric power of the evaporator is 1.7 kilowatts, the voltage of 220 volts, the electric current 8 A, the heater resistance of 27.5 Ohms. The evaporator yield is 50%. The evaporator is equipped with a pressure gauge of up to 10 atmospheres and a thermocouple in the outlet connection.

The water evaporation block (EA) is designed for the evaporation of water and can be running continuously for 1 hour (between filling). The volume of the water evaporator is 2.5 liters. Water vapor consumption is 1.6 kg hour. The temperature of the outlet water vapor is 100 ° C. The electric power of the evaporator is 2.3 Kilowatts, the voltage of 220 volts, the electric current 11 A, the heater resistance of 22 Ohms. The evaporator yield is 50%. The evaporator is equipped with a pressure gauge of up to 10 atmospheres and a thermocouple in the outlet connection.

The air supply (AA) block is designed to supply pumped air to the Prototype. The air productivity of your compressor is 12 nanometers ³ hours (16 kg hours). The air outlet pressure shall not be less than 3 atmospheres. The pumped air flows into the heat exchanger to recover the heat of the synthesis gas and subsequently, inside the inlet chamber.

Conceptual Design of the Plasmacatalytic Reactor based on a quasi-stationary Discharge.

The plasmacatalytic converter of motor fuel impulses in a synthesis gas, is based on the use of a periodic impact microwave discharge equipped with a high driving power (100-200 Kilowatts), in the short duration of an impulse (lμs) and in the large porosity of the periodic impact method (around 1000 in the pulse repetition frequency of 1 Kiloherzio). This approach provides the small ratio P _δ / P _p of electrical power from the discharge P _δ to the preliminary heating power of the reagent P _p .

Currently, the preliminary heating of the reagent (on account of oxidation), is also transformed into energy of the _chemical system P, required for the completion of the endothermic conversion procedure: P _p is close to _chemical P. This fact constitutes the main advantage of the microwave plasma converter. At the same time, in a technological variable of the converter to carry out the preliminary heating of a reagent, it is natural that combustion energy (oxidation), a part of oxygen fuel from the air, is used. On the other hand, there are microwave plasma devices that allow, at present, a conversion procedure to a part of the fuel. In other words, a discharge of the torch from the quasi-stationary microwaves (the duration of a pulse of radiation is around one tenth of a meter per second, the porosity of a periodic impact method is about 2). The stability of the operation of said devices, at a given atmospheric pressure, is provided by the use of specific properties of microwave resonators. Whenever the significant part of the Energy used for the maintenance of electric shock will be valid, if it is obtained from the procedure of burning a part of fuel in a discharge zone, said converter will maintain, the basic advantage of the microwave plasma converter, the small ratio P _δ IP _quítτάca will be desirable. These sources are, on average, much more powerful than impulse analogs (with a lower maximum power). Therefore, the almost fixed converter, in any case, is influenced by the fixed hydrogen power converters of high productivity. At the same time, quasi-stationary sources of microwave radiation for the type of discharge given are cheaper, smaller and less heavy, which is essential for selecting a converter variable. The manufacture of the converter equipped with a power of the order of 1 Kilowatt will not cause any essential difficulties. Therefore, as described above, in the optimization of power flows (first of all, the ratio P _δ / P _chem i _ca ) _> said converter represents the urgent need to obtain an alternative design of the System Prototype selected. The conceptual design variable of the Prototype of the converter - based on the quasi-stationary microwave discharge - will be described below.

As previously indicated, by means of the perspective scheme of the Prototype of the converter based on the partial process of oxidation of fuel, the scheme of the discharge of the torch of quasi-stationary microwaves is also indicated. The discharge of the type provided exists in an atmosphere of 500/1000 watts. The output of the synthesis gas from the converter could reach the order of 10-20 nanometers ³ / hour, which corresponds to a deposit of energy in the initial reagent, of the order of 0.5 eV / mol. Said level of energy deposit is characteristic for the above described scheme of the converter based on the discharge of periodic impacts. In this way, the system provided can represent itself, as the Catalyst of the conversion process into a fairly low plasma energy reservoir. The scheme described above is convenient for carrying out the partial process of oxidation of the fuel in a synthesis gas. In this way, the previously heated reagent 5 is not needed, since the reaction is exothermic. A basic portion of energy enters the system, not as a discharge plasma, but during combustion. On the other hand, the assigned energy can be partially used to perform the vapor-oxygen conversion of the fuel. In this way, the proportions of a mixture of fuel vapor, water and air will be provided, so that the entire conversion process is transformed into a thermoneutral procedure. The diagram of the converter prototype block is shown in Figure 3. For the evaporation of fuel and water (water - in the steam-oxygen conversion variable), two steam generators are used. (In the variables of a design, it is possible to inject a liquid reagent into the reactor). The fuel vapor and water are mixed with air and move over an inlet of a plasmotron of the microwave torch.

The parameters of a microwave radiation source, which can be used to design the Prototype of the converter, of the type provided above (as an example of a radiation source, the standard magnetron of a domestic microwave oven can be considered):

almost fixed method; 5 frequency 2.45 Gigaherzios; impulse power of 1.2 Kilowatts average power 600 watts.

The mixture of fuel, water and air vapors sends us to a discharge zone or zone through a tobo, which is simultaneously constituted as an internal explorer of a coaxial line The output of the microwave radiation from the resonator in a coaxial line is carried out with the help of a closed current circuit. The reactor chamber also represents the microwave radiation resonator. Currently, the converter's electrodynamic scheme is represented by the system consisting of two microwave resonators connected to each other. The presence of the resonator in the reactor chamber will facilitate interruption. Virtually all gas passes through a plasma torch. A high degree of evolutionary operation of the reagent will be achieved, through the plasma. To divide a cavity of the first resonator and the discharge chamber, it is necessary to use an adjusted condensation, which should simultaneously be transparent to microwave radiation. Since preliminary heating (see Figure 3) only serves to evaporate fuel and water, then the reagent will act in the chamber at a temperature that does not exceed 400 ° C. In this way, in order to perform a tight division of the resonator and the chamber, a condensation of transparent microwave teflon can be used.

One of the advantages of the system described above is its strength. To power a magnetron it is possible to use the simple power supply, which is not contained in the rectifier. In contrast to the converter based on the discharge of periodic impacts, depending on the design provided above, the modulator that feeds the magnetron may not be required. It is also possible to use the magnetron of a microwave oven. The system is distinguished by its simplicity and its low price.

Claims

R E I V I N D I C A C I O N E S

I ^a .- Method for plasmacatalytic conversion of a fossil fuel (MF) into synthetic gas (syn-gas), in which reactions are carried out between the hydrocarbons present in said MF and air or between said hydrocarbons, water vapor and air, which comprises: preheating the air; incinerate part of the MF with which reaction products and residues are obtained; mixing said wastes with the combustion products and, optionally, with water vapor, whereby a reaction mixture is obtained; and bringing said reaction mixture into a plasmacatalytic reactor where the plasma acts as a catalyst accelerating the conversion of MF into a synthesis gas (syn-gas).

2 .- Method according to claim 1, wherein said plasmaquímica acceleration conversion MF syn-gas is performed either by passing the reaction mixture through plasma periodic pulse discharge in a continuous unloader pseudocorona effect pressure atmospheric, or by passing the reaction mixture through a plasma with a quasi-stationary torch effect with a radiation pulse length of less than 100 milliseconds (ms).

3 .- Method according to claim 1, wherein in a subcritical reactor plasmacatalytic value of electric field intensity of the microwave pulses is established, a discharge starts pseudocorona injectors microwave at the edges of the elements of the crown, and an electric field equal to or greater than 1,000 kV / cm is established on the heads of the microwave injectors. 4 .- Method according to claim 3, wherein the power source generates microwaves set pulse with a duration of the impulse ranging between 0.1 and 1 microseconds () and a ratio of pulse period duration Pulse between 100 and 1,000 in a microwave radiation range included within the X and S bands, with specific impulse power, which provide the necessary level of electric field in the resonator and in the heads of the continuous microwave arresters.

5 .- A method according to claim 4, wherein the power input in plasma is between 0.05 and 0.2 kWh / m ^3, controlled so that the input value of plasma energy does not exceed 10 % of the enthalpy value of the reagent at the working temper.

6 .- Method according to claims 1 and 4 or 5, wherein plasmacatalytic converting the MF syn-gas, steam and air, and temperatoras of reactants is performed by reaction between hydrocarbons present in said MF at the entrance of the plasmacatalytic reactor are between 800 K and 15,000 K.

7 .- method according to any of claims 1, 4 or 6, wherein the ratio of the MF part incinerated and residue is between 0.5 and 2.

8 ^a - Method according to claims 1 and 4 or 5, wherein the plasma-catalytic conversion of the MF into syn-gas is carried out by reaction between the hydrocarbons present in said MF and air, and the reactant temperators of the reactor inlet plasmacatalytic are between 600 K and 1,100 K. 9 .- Method according to claim 8, wherein the ratio of the MF part incinerated and residue is between 0.4 and 2.

10 .- Method according to claim 9, wherein the molar ratio air / MF to the input of the plasmacatalytic reactor is between 16 and 20.

11 .- plasmacatalytic Apparatus for converting fossil fuels into a hydrogen rich gas according to the method of one or more of the preceding reivnidicaciones, characterized therein a fuel evaporator (EC) engaged a water evaporator ( EA) and an air feeder (AA), which supply the respective materials, through a heat exchanger (IC), the air and part of the fuel to an inlet chamber (CE) and the water and the rest of the fuel to a mixing chamber (CM), which also receives the materials from the inlet chamber (CE), feeding said mixing chamber to a chemical reactor (RQ) assisted by a microwave generator (GM) to obtain a synthesis gas (GS).

12 .- apparatus plasmacatalytic conversion fosnes fuel into a hydrogen rich gas according to claim 11, characterized in that the inlet chamber (CE) incorporating a plurality of injectors (I) in axial arrangement, for the fuel and air , arranged alternately, and continued without continuity solution in the mixing chamber (CM), in which the water and fuel injectors (I) are radially established.

13 .- plasmacatalytic Apparatus for converting a fuel fósües hydrogen rich gas according to claim 11, characterized in that the microwave generator (GM) comprises a modulator, a magnetron, .. waveguide system and a unit for the entrance of microwave energy inside the reactor (RQ).

14 .- apparatus plasmacatalytic converting fossil fuels into a hydrogen rich gas according to claim 11, wherein the chemical reactor (RQ) is a guide spherical waves with a sealed coupling (AH) to the microwave generator ( GM), with a metal piston (PM) on the opposite side, provided with holes (T) to visualize the microwave discharge, discharge that starts with a pointed tungsten needle inserted in the chemical reactor (RQ), specifically in a hole () of the waveguide wall, said tungsten needle being movable in the direction of its axis.

15 .- apparatus plasmacatalytic converting fossil fuels into a hydrogen rich gas according to claim 14, characterized in that said sealing engagement (AH) consists of a quartz plate that is installed perpendicular to the waveguides.

16 .- apparatus plasmacatalytic converting fossil fuels into a hydrogen rich gas according to claim 11, wherein the heat exchanger (IC) is a camera attached to the wall of the guide spherical waves corresponding to the chemical reactor , so that its axes are perpendicular to each other, placing stainless tubes inside it to enter water, fuel and air in parallel arrangement with its own axis.