METHOD AND REACTOR FOR PROCESSING A GAS

Abstract

A plasma processing method for a gas comprises supplying a gas inside a cavity for plasma processing, supplying microwaves having a predetermined frequency and power in order to generate a plasma of the gas, and propagating the microwaves in the gas by means of a waveguide which communicates directly with the cavity so as to provide a plasma cracking processing operation for the gas inside the cavity (2).

Claims

1. A plasma processing method for a gas, comprising: supplying a gas inside a cavity (2) for plasma processing, supplying microwaves having a predetermined frequency and power in order to generate a plasma of the gas, propagating the microwaves in the gas by means of a waveguide (6) which communicates directly with the cavity (2) so as to provide a plasma cracking processing operation for the gas inside the cavity (2), the internal volume with respect to the cavity (2) and the waveguide (6) not having any discontinuities, receiving the gas and the microwaves from the waveguide (6) in a processing pipe (4) of the cavity (2), conveying the gas and the microwaves inside an electromagnetic resonator (7) which is arranged along the processing pipe (4), the electromagnetic resonator (7) being in the form of a widening of the processing pipe (4) and concentrating the microwaves so as to generate a plasma of the gas inside the electromagnetic resonator (7).

2. A method according to claim 1, comprising receiving the gas and the microwaves in the electromagnetic resonator (7) only after the gas and the microwaves have been discharged from the waveguide (6).

3. A method according to claim 1 or 2, wherein the electromagnetic resonator (7) is arranged along the processing pipe (4) downstream of the waveguide (6) in relation to a direction of flow of the gas and propagation of the microwaves by the waveguide (6) towards the processing pipe (4).

4. A method according to any one of the preceding claims, wherein the electromagnetic resonator (7) along the processing pipe (4) is spaced apart from the waveguide (6) by a first distance (W1).

5. A method according to any one of the preceding claims, wherein the microwaves propagate from the waveguide (6) to the cavity (2) through the gas without encountering any obstacle.

6. A method according to any one of the preceding claims, wherein the generation of the plasma inside the cavity (2) is fed by the gas without adding any additional gas being introduced into the cavity (2) intended to sustain the generation of the plasma inside the cavity (2).

7. A method according to any one of the preceding claims, wherein the gas comprises a pyrolysis gas.

8. A method according to any one of the preceding claims, wherein the plasma cracking comprises heating the plasma up to a temperature between 2500° C. and 4000° C.

9. A method according to any one of the preceding claims, wherein the plasma cracking is carried out at atmospheric pressure.

10. A plasma-chemical reactor (1) for carrying out the plasma processing method for a gas according to any one of the preceding claims, comprising a plasma processing cavity (2) which is configured to receive the gas inside the cavity (2), an electromagnetic wave source which is configured to supply microwaves having a predetermined frequency and power in order to generate a plasma of the gas inside the cavity (2), a waveguide (6) which communicates directly with the cavity (2), the internal volume with respect to the cavity (2) and the waveguide (6) not having discontinuities, the waveguide (6) being configured to receive the microwaves from the electromagnetic wave source and to propagate the microwaves in a guided manner in the cavity (2) through the gas so as to provide a plasma cracking processing operation for the gas inside the cavity (2), the cavity (2) comprising an inlet pipe (3) which is configured to convey the gas towards the waveguide (6) and a processing pipe (4) which is configured to receive the gas and the microwaves from the waveguide (6) so as to provide the plasma cracking processing operation for the gas inside the processing pipe (4) and an electromagnetic resonator (7) which is arranged along the processing pipe (4), the electromagnetic resonator (7) being configured to receive the gas and the microwaves along the processing pipe (4) and to concentrate the microwaves inside the electromagnetic resonator (7) so as to generate a plasma of the gas passing through the electromagnetic resonator (7), the electromagnetic resonator (7) being in the form of a widening of the processing pipe (4).

11. A reactor (1) according to claim 10, wherein the electromagnetic resonator (7) is arranged downstream of the waveguide (6) along the processing pipe (4) in relation to a direction of flow of the gas and propagation of the microwaves by the waveguide (6) towards the processing pipe (4).

12. A reactor (1) according to claim 10 or 11, wherein the electromagnetic resonator (7) along the processing pipe (4) is spaced apart from the waveguide (6) by a first distance (W1).

13. A reactor (1) according to claim 12, wherein the processing pipe (4) has a first diameter (D1), the first distance (W1) being greater than the first diameter (D1).

14. A reactor (1) according to claim 13, wherein the first distance (W1) is between two and ten times the first diameter (D1).

15. A reactor (1) according to claim 13, wherein the first distance (W1) is between four and seven times the first diameter (D1).

16. A reactor (1) according to any one of claims 12 to 15, wherein the electromagnetic resonator (7) extends along the longitudinal extent of the processing pipe (4) over a second distance (W2) which is less than the first distance (W1).

17. A reactor (1) according to claim 16, wherein the first distance (W1) is between two and ten times the second distance (W2).

18. A reactor (1) according to claim 16, wherein the first distance (W1) is between four and eight times the second distance (W2).

19. A reactor (1) according to any one of claims 10 to 18, wherein the waveguide (6) has a hollow linear structure which extends along a first axis (X).

20. A reactor (1) according to claim 19, the hollow linear structure of the waveguide (6) having a rectangular cross-section.

21. A reactor (1) according to any one of claims 10 to 20, wherein the cavity (2) and/or the inlet pipe (3) and/or the processing pipe (4) have a hollow linear structure which extends along a second axis (Y).

22. A reactor (1) according to claim 21 when dependent on claim 19 or 20, wherein the second axis (Y) is perpendicular to the first axis (X).

23. A reactor (1) according to claim 21 or 22, the hollow linear structure of the cavity (2) and/or the inlet pipe (3) and/or the processing pipe (4) having a circular cross-section.

24. A reactor (1) according to claim 22, wherein the linear structure of the waveguide (6) extends along the first axis (X) over a first length (L1) and along the second axis (Y) over a second length (L2), the first length (L1) being from three to ten times the second length (L2).

25. A reactor (1) according to claim 24, wherein the first length (L1) is from six to seven times the second length (L2).

26. A reactor (1) according to claim 24 or 25, wherein the cross-section of the waveguide (6) extends in a direction perpendicular to the plane defined by the first axis (X) and the second axis (Y) over a third length (L3), the second length (L2) being from one to two thirds of the third length (L3).

27. A reactor (1) according to claim 26, wherein the second length (L2) is substantially half of the third length (L3).

28. A reactor (1) according to any one of claims 10 to 27, wherein the electromagnetic resonator (7) has a hollow cylindrical structure which extends along the second axis (Y) of the processing pipe (4), the hollow cylindrical structure having a cross-section greater than a cross-section of the processing pipe (4).

29. A reactor (1) according to claim 28, wherein the processing pipe (4) has a first diameter (D1), the electromagnetic resonator (7) having a second diameter (D2) greater than the first diameter (D1).

30. A reactor (1) according to claim 29, wherein the second diameter (D2) is less than double the first diameter (D1).

31. A reactor (1) according to any one of claims 28 to 30, wherein the electromagnetic resonator (7) has a second diameter (D2) and extends along the longitudinal extent of the processing pipe (4) over a second distance (W2) less than or approximately equal to the second diameter (D2).

32. A reactor (1) according to any one of claims 10 to 31, wherein the electromagnetic resonator (7) does not have moving parts.

33. An installation (100) for pyrolysis and/or gasification of biomass, comprising a pyrolyzer and/or gasifier (13) which is configured to supply a pyrolysis gas which is generated by the pyrolysis and/or gasification of the biomass and furthermore the reactor (1) according to any one of claims 10 to 32, the reactor (1) being configured to receive the pyrolysis gas and to provide a plasma cracking processing operation for the pyrolysis gas.

Description

[0054] The features and advantages of the invention will be better appreciated from the following detailed description of a preferred though non-limiting embodiment thereof which is illustrated by way of non-limiting example with reference to the appended drawings, in which:

[0055] FIG. 1 is a perspective view of the plasma-chemical reactor according to the invention;

[0056] FIGS. 2 and 3 are a front view and a side view of the reactor of FIG. 1, respectively;

[0057] FIG. 4 is a perspective cross-section along the line IV-IV of the reactor of FIG. 3;

[0058] FIG. 5 is a connection diagram of the reactor according to the invention;

[0059] FIG. 6 is a diagram of an installation according to the invention;

[0060] FIGS. 7 and 8 are a front view and a perspective view of a distribution model of the standard of the electrical field (V/m) inside the reactor of FIG. 1 according to a numerical simulation, respectively;

[0061] FIG. 9 illustrates a temperature profile (K) of the plasma inside the reactor of FIG. 1 according to a numerical simulation;

[0062] FIG. 10 illustrates the progression of the temperature (° C.) of the plasma along an axis of the reactor of FIG. 1 as a function of the power (kW) of the reactor itself according to a numerical simulation.

[0063] In the Figures, there are generally designated 1 and 100 a chemical reactor for processing plasma of a gas and an installation for pyrolysis and/or gasification of biomass comprising the reactor 1, respectively.

[0064] It will be appreciated that, preferably, the gas is an admixture of gases and, even more preferably, comprises a pyrolysis gas. Advantageously, the plasma processing of the gas comprises a cracking processing of the gas. The reactor 1 comprises a cavity 2 for plasma processing which is configured to receive the gas inside the cavity 2. It will be appreciated that the cavity 2 is preferably confined inside a tube which is suitable for withstanding high temperatures, such as the temperatures of a plasma torch.

[0065] There is further provided an electromagnetic wave source (not shown) which is configured to supply microwaves having a predetermined frequency and power in order to generates a plasma of the gas inside the cavity 2. It will be appreciated that the density of the electrons is higher in the microwave plasma with respect to other types of plasma, such as, for example, in the radiofrequency plasma (RF) or direct current plasma (DC).

[0066] It must be observed that the source of electromagnetic waves may include a power supply, a magnetron and preferably a circulator in order to protect the magnetron from the reflected power.

[0067] There is further provided in the reactor 1 a waveguide 6 which communicates directly with the cavity 2. In other words, the internal volume defined by the waveguide 6 is advantageously in communication with the internal volume defined by the cavity 2, preferably without any physical separation elements. The waveguide 6 is configured to receive the microwaves from the electromagnetic wave source and to propagate in a guided manner the microwaves in the cavity 2 through the gas so as to provide the plasma cracking processing for the gas inside the cavity 2.

[0068] In an aspect, as set out in FIG. 4, the internal volume with respect to the cavity 2 and the waveguide 6 does not have any discontinuities. In this manner, there can be generated a common intersection ne between the two volumes in which the gas is directly struck by the microwaves.

[0069] According to another advantageous aspect, the cavity 2 has an inlet pipe 3 which is configured to convey the gas towards the waveguide 6 and a processing pipe 4 which is configured to receive the gas and the microwaves from the waveguide 6 so as to provide the plasma cracking processing for the gas inside the processing pipe 4.

[0070] In preferred embodiments, the waveguide 6 has a hollow linear structure which extends along a first axis X from a first end 5in towards a second end 50. In an aspect, the first end 5in is directed towards the electromagnetic wave source. Advantageously, the first end 5in is closed with a material which is transparent to electromagnetic waves emitted by the source so as to receive the electromagnetic waves emitted by the source. According to another advantageous aspect, the first end 5in is closed with glass and/or quartz.

[0071] Preferably, the electromagnetic wave source is located at or adjacent to the first end 5in of the waveguide 6. However, the second end 50 is directed at the opposite side to the source. Preferably, the second end 50 is closed and is not transparent to the electromagnetic waves which are propagated inside the waveguide 6.

[0072] It will be appreciated that, preferably, the inlet pipe 3 is engaged in the waveguide 6 at a first section 36 and communicates directly with the waveguide 6 through the first section 36, as set out in FIG. 4. Similarly, the processing pipe 4 is engaged in the waveguide 6 at a second section 46 and communicates directly with the waveguide 6 through the second section 46. In this context, the waveguide 6 is configured to convey the microwaves from the source towards the cavity 2, preferably through the first section 36 and/or the second section 46, as shown in FIGS. 7 and 8 according to a numerical simulation of the electrical field inside the reactor. The cavity 2 is in turn configured to receive the microwaves from the waveguide 6 and to convey the microwaves through the gas inside the cavity 2.

[0073] It must be observed that, in an aspect, the microwaves are propagated by the waveguide 6 to the cavity 2 through the gas without encountering any obstacle.

[0074] Advantageously, the microwaves are transmitted inside the waveguide 6 and the cavity 2 so that the energy is transmitted to the electrons of the gas which supplies the plasma.

[0075] Under these conditions, the electromagnetic field accelerates the electrons. During the collisions with the heavy particles, the movement energy of the electrons is converted into heat. If the collisions are frequent enough, the distribution of the velocities of the electrons is virtually isotropic and the characteristics of the excitation and ionization processes can be calculated using the Maxwell distribution function for the velocities of the electrons, disregarding the directional velocity (velocity of the flux of mass).

[0076] According to another advantageous aspect, the inlet pipe 3 at the opposite side to the waveguide 6 comprises an inlet opening 3in. Similarly, the processing pipe 4 at the opposite side to the waveguide 6 comprises an outlet opening 4out.

[0077] In this context, the cavity 2 is configured to generate a plasma jet, that is to say, a plasma torch, through the processing pipe 4. It must be observed that the plasma is generated directly in the gas (for example, pyrolysis gas) and, consequently, the molecules of gas are subjected to ionization. Advantageously, there is no provision for supplying an additional gas (for example, argon) other than the gas (for example, pyrolysis gas) for generating or sustaining the plasma. This gas supply system allows the efficiency of the process to be increased.

[0078] In preferred embodiments, the hollow linear structure of the waveguide 6 has a rectangular cross-section. It will be appreciated that the dimensions of the waveguide 6 and the operating frequency of the electromagnetic waves are selected to cause the electromagnetic waves to be propagated inside the waveguide 6 in the fundamental mode (that is to say, in the mode with the lowest critical frequency) which preferably corresponds to the transverse electrical mode TE.sub.1.0.

[0079] In an aspect, the cavity 2 and/or the inlet pipe 3 and/or processing pipe 4 have a hollow linear structure which is developed along a second axis Y. It will be appreciated that the first axis X and the second axis Y are transverse relative to each other. Preferably, the first axis X and the second axis Y are perpendicular to each other. In an aspect, the hollow linear structure of the cavity 2 and/or the inlet pipe 3 and/or processing pipe 4 has/have a circular cross-section.

[0080] As shown in FIG. 2, the linear structure of the waveguide 6 may extend along the first axis X over a first length L1 and along the second axis Y over a second length L2. Furthermore, as shown in FIG. 3, the cross-section of the waveguide 6 may extend in a perpendicular direction relative to the plane defined by the first axis X and the second axis Y over a third length L3. It will be appreciated that the first length, second length and third length L1, L2, L3 depend on parameters such as, for example, the flow rate and the pressure of the gas in the reactor. In some embodiments by way of non-limiting example, the first length L1 (for example, 780 mm) is from three to ten times the second length L2 and preferably from six to seven times the second length L2 (for example, 124 mm) which may in turn be from one to two thirds of the third length L3 and preferably substantially half of the third length L3 (for example, 248 mm).

[0081] It must be observed that, advantageously, the inlet pipe 3 and processing pipe 4 of the cavity 2 are directly open in the internal volume of the waveguide 6 without any interruption of continuity between the internal volume of the waveguide 6 and the inlet pipe 3 and processing pipe 4.

[0082] In an aspect, the reactor 1 comprises an electromagnetic resonator 7 along the processing pipe 4. The electromagnetic resonator 7 is configured to receive the gas and the microwaves along the processing pipe 4 and to concentrate the microwaves inside the electromagnetic resonator 7 so as to generate a plasma of the gas passing through the electromagnetic resonator 7. According to another advantageous aspect, the electromagnetic resonator 7 has a hollow cylindrical structure which is developed along the second axis Y of the processing pipe 4. Preferably, the hollow cylindrical structure has a cross-section which is greater than the cross-section of the processing pipe 4.

[0083] In a preferred example, it is possible to define a first diameter D1 of the processing pipe 4 and a second diameter D2 of the electromagnetic resonator 7. Preferably, the second diameter D2 is greater than the first diameter D1 and, in some embodiments, may be up to double the first diameter D1.

[0084] More generally, according to an aspect of the invention, the resonator 7 is in the form of a widening of the processing pipe 4 and/or the cavity 2.

[0085] In some embodiments, the electromagnetic resonator 7 is spaced apart from the waveguide 6 along the processing pipe 4 by a first distance W1 which is preferably greater than the first diameter D1. The first distance W1 is, for example, between two and ten times the first diameter D1 and, in a preferred example, is between four and seven times the first diameter D1.

[0086] Still in some embodiments, the electromagnetic resonator 7 extends along the longitudinal extent of the processing pipe 4 over a second distance W2 which is preferably less than the first distance W1. The first distance W1 is, for example, between two and ten times the second distance W2 and, in a preferred example, it is between four and eight times the second distance W2. It is further preferable for the second distance W2 to be less than or approximately equal to the second diameter D2 of the resonator.

[0087] In this manner, when the microwaves being discharged from the waveguide 6 through the processing pipe 4 approach the electromagnetic resonator 7, the concentration thereof increases more and more, involving a localized increase of the temperature of the plasma at the centre of the electromagnetic resonator 7 as shown by the temperature profile in FIG. 9 in accordance with a numerical simulation carried out by the Applicant.

[0088] It must be observed that, in the region of the electromagnetic resonator 7, the plasma reaches the maximum temperature which makes the plasma processing and the cracking possible via the reactor 1. In this manner, it is possible to destroy the dangerous molecules (long and/or aromatic and/or toxic molecules) and to convert them into useful molecules without further affecting the useful molecules already present in the gas so as to produce a synthesis gas.

[0089] Advantageously, the hollow cylindrical structure of the resonator 7 has an adjustable diameter as a function of process parameters, such as, for example, the concentration of the gas, the quantity and pressure of the gas, the frequency and power of the microwaves, and the like.

[0090] It must be observed that, when the gas is supplied directly to the plasma torch, all the gas passes through the region of high temperatures necessary for the chemical reactions of dissociation, while the temperature of the gas does not increase significantly. This allows a reduction in the consumption of energy for the processing of the gas while maintaining the efficiency thereof. During operation of the reactor 1, the admixture of gas is introduced into the reactor from the inlet opening 3in of the inlet pipe 3 at a given volumetric flow (for example, 0.05 m.sup.3/s) and is discharged out of the reactor from the outlet opening 4out of the processing pipe 4. In an aspect, the inflow of gas in the inlet pipe 3 has a high temperature (for example, from 700 to 900° C.). It will be appreciated that the speed of the gas increases as the gas flows through the cavity 2 from the inlet opening 3in towards the outlet opening 4out, passing through inter alia the first section 36 and the second section 46. The increase of the speed results from the fact that the temperature increases further with greater proximity to the resonator 7.

[0091] As shown by the temperature profile in the example of FIG. 9, the temperature of the plasma increases radially from the walls of the cavity 2 towards the second axis Y of the cavity 2. Furthermore, the temperature is greater when the electromagnetic waves approach the resonator 7, as shown in the example of FIG. 10 by the increasing progression of the temperature (° C.) at the centre of the plasma along the axis of the processing pipe 4 from the inlet opening 3in towards the resonator 7. As a result of the accumulation of electromagnetic waves, therefore, the maximum temperature is reached at the centre of the resonator 7 and near the outlet opening 4out.

[0092] It will be appreciated that the maximum temperature depends inter alia on the operating power P of the reactor, as shown, for example, in FIG. 10 in relation to four power levels of the reactor equal to 75 kW, 100 kW, 150 kW or 175 kW. In an aspect, the operating power P of the reactor 1 may vary, for example, between 3 kW and 175 kW. The maximum temperatures at the centre of the plasma (for example, between 2000 and 6000° C. or preferably between 2500 and 400° C.) allow the thermal cracking and the plasma cracking of the gases introduced into the reactor 1.

[0093] It must be observed that, advantageously, the plasma induced by microwaves does not require a fixed pressure and is also stable at different pressure ranges. According to another advantageous aspect, the cracking of the gas may be brought about at low pressures (for example, from 10 to 80 mbar) or at atmospheric pressure. It will be appreciated that the pressure depends inter alia on the quantity of gas with which the reactor is supplied. Furthermore, the increase of the pressure during the cracking in the vapour phase advantageously reduces the volume of vapour, feedstock and cracking products and this allows an increase in the productivity of the installation or an increase in the length of time of the feedstock in the reaction ne. At the same time, the pressure significantly influences the composition of the cracking products because the pressure increases the rate of secondary reactions (such as polymerization and hydrogenation of unsaturated hydrocarbons, condensation of aromatic hydrocarbons, etc.), reducing the production of gas.

[0094] In an aspect, the gas admixture which is intended to be introduced into the reactor 1 comprises one or more components. In this context, the energy consumption for heating all the components of the gas in kJ is preferably calculated using the formula:

Q.sub.iH=V.sub.ic.sub.iΔt.sub.i

where V.sub.i is the volume in m.sup.3 of each component of the gas; C.sub.i is the thermal capacity of each component in kJ/(m.sup.3×C) at the temperature of 1000° C.; and Δt.sub.i is the increase of the temperature of the gas in degrees Celsius (or Kelvin).

[0095] Furthermore, the energy consumption for the dissociation of the tarry substances in kJ is preferably calculated using the formula:

[00001]$Q_{\mathrm{ip}}=1000\frac{V_i\left(-\Delta H_i\right)}{22.4}$

where (−ΔH.sub.i) is the energy consumption for the dissociation of a substance, which is equal to the specific formation enthalpy of the substance itself taken with the opposite sign.

[0096] It is advantageously possible to obtain an additional reduction of the energy consumption using the catalytic properties of the plasma. In fact, it will be appreciated that the chemical reactions in the plasma take place more rapidly than in other means for the same temperature. Therefore, it is possible to reduce the temperature in order to obtain the same chemical reactions with a reduction of the energy consumption.

[0097] The experimental results obtained by the Applicant demonstrate that it is possible to obtain a conversion of substantially 100% of the tarry substances in the gas at the processing temperature of the gas of 100° C. at the outlet.

[0098] In an aspect, the present invention relates to an installation 100 for the pyrolysis and/or gasification of biomass, as shown in FIG. 6. It will be appreciated that the installation 100 comprises a pyrolyzer and/or gasifier 13 which is configured to supply a pyrolysis gas which is generated by the pyrolysis and/or gasification of the biomass and furthermore the reactor 1, which may be connected according to the diagram of FIG. 5. In this context, the reactor 1 is configured to receive a pyrolysis gas which is generated by the pyrolysis and/or gasification of the biomass and to provide a plasma cracking processing operation for the pyrolysis gas. It will be appreciated that the reactor 1 behaves in the manner of a microwave plasma filter which is configured to remove the tarry substances from the pyrolysis gas. The effective conversion of the tarry substances is promoted both by a high peak temperature in the plasma and by the high turbulence generated by the plasma.

[0099] The operation of the installation initially provides for a thermochemical degradation or decomposition step for the biomass without any or in the partial presence of oxygen. The degradation step comprises the pyrolysis and/or gasification of the biomass. This step generates a pyrolysis gas. Afterwards, there is provided a plasma processing step for cracking the pyrolysis gas. The step of plasma processing provides for supplying the pyrolysis gas inside the plasma processing cavity 2, supplying microwaves having a frequency and power which are predetermined to generate a plasma of the pyrolysis gas, and propagating the microwaves in the pyrolysis gas by means of the waveguide 6 so as to provide the plasma cracking processing of the pyrolysis gas inside the cavity 2 by splitting the heavy paraffinic hydrocarbon molecules.

[0100] In preferred embodiments, the installation 100 comprises a pyrolysis gas distributor 12 which supplies the inlet pipe 3 of the reactor 1 by providing pyrolysis gas. Preferably, the distributor 12 includes a pyrolyzer or gasifier 13 and a cyclone 14. It will be appreciated that the pyrolyzer or gasifier 13 is configured to supply the cyclone 14 which is in turn configured to supply the pyrolysis gas to the reactor 1.

[0101] In an aspect, the pyrolysis gas distributor 12 is operationally connected to the reactor 1 by means of a supply tubing 16 which is engaged in the inlet pipe 3. Advantageously, there is provided in the installation 100 a flowmeter 8 which is configured to measure a flow rate of a flux of the gas being introduced towards the reactor 1. In an aspect, the flowmeter 8 is arranged in the region of the supply tubing 16.

[0102] There is preferably provided a discharge device 15 which is configured to receive the gas being discharged from the reactor 1. In an aspect, the discharge device 15 comprises cooling means which are configured to cool the gas being discharged from the reactor 1. It will be appreciated that the discharge device 15 is operationally connected to the reactor 1 by means of a discharge tubing 17 which is operationally connected to the outlet opening 4out of the processing pipe 4.

[0103] It will be appreciated that the reactor 1 can be installed in a pre-existing cracking installation by providing minimal modifications to the pre-existing installation, as shown in the example of FIG. 6. Advantageously, the reactor 1 may be mounted upstream of a pre-existing cracking chamber 18 of the installation. No longer being used for the plasma processing, the cracking chamber 18 can be used to provide the passage of the discharge tubing 17 through the cracking chamber 18 from the reactor 1 towards the discharge device 15.

[0104] According to another advantageous aspect, there is provided a temperature sensor 9 which is configured to measure a temperature of the gas being discharged from the reactor 1. In an aspect, the temperature sensor 9 is arranged in the region of the discharge tubing 17.

[0105] Preferably, the installation 100 further comprises at least one shut-off valve 10 which is configured to regulate or intercept a flow of the gas being introduced towards the reactor 1. It will be appreciated that the shut-off valve 10 is advantageously arranged in the region of the supply tubing 16, preferably upstream of the flowmeter 8.

[0106] Advantageously, there is further provided at least one collection valve 11 which is configured to collect a portion of the gas being introduced into the reactor 1 or being discharged from the reactor 1. In some preferred embodiments, there are provided a collection valve 11 which is configured to collect a portion of the gas in the region of the supply tubing 16 (preferably downstream of the flowmeter 8) and an additional collection valve 11′ which is configured to collect a portion of the gas in the region of the discharge tubing 17 (preferably downstream of the temperature sensor 9). In this manner, it is possible to carry out sampling of the pyrolysis gas before and after the plasma cracking processing operation, thereby allowing rapid modification of the parameters of the plasma torch (energy consumption, flow, gas composition, etc.) so as to adapt the system dynamically to the requirements for gas plasma processing.

[0107] In an aspect, the technology proposed is further used in the processing of wood waste. In fact, it has to be observed that the pyrolysis of the wood waste generates high quantities of tarry substances (powdered carbon) while the resulting pyrolysis gas after the cracking from toxic gases can be used for energy purposes without any additional purification from the tarry substances. If the wood contains a sufficient level of humidity between 40 and 60%, the surface processing thereof starts with the pyrolysis (carbonization) and the resultant release of volatile compounds. In a state subjected to plasma cracking, the compounds contained in the pyrolysis gas become decomposed by conversion reactions in the volume of the plasma discharge. These compounds produce a high quantity of an admixture of hydrogen gas while the components of the wood are stratified in an aqueous solution of organic compounds (acids, carbohydrates, phenols, etc.) and in an oily combustible liquid. The heat content of the oily liquid reaches 24×103 kJ/kg which significantly exceeds the heat of combustion of the wood (14×103 kJ/kg). It will be appreciated that, if the processing process continues further, these components readily change into the gaseous state, with a subsequent conversion and production of practically pure carbon monoxide and hydrogen. The invention thereby solves the problem proposed, achieving a number of advantages including: [0108] compactness and low weight as a result of the high specific power, [0109] high efficiency of pyrolytic plasma conversion, [0110] minimal cost, [0111] rapid response time in the order of fractions of a second, [0112] compatibility with a wide range of fuels, including heavy or crude hydrocarbons and “dirty” hydrocarbons with a high content of sulphur, [0113] generation of plasma at different pressure ranges and in a stable manner, [0114] high quality of cracking over substantially 100% of the gas, [0115] cracking of the powdered carbon, thereby eliminating the need for any filters for the powdered carbon.