EP4658735A1

EP4658735A1 - Syngas production plant

Info

Publication number: EP4658735A1
Application number: EP24705565.0A
Authority: EP
Inventors: Remo UCCELLARI
Original assignee: Pfg Hybrid Srl
Current assignee: Pfg Hybrid Srl
Priority date: 2023-02-03
Filing date: 2024-01-29
Publication date: 2025-12-10
Also published as: IT202300001812A1; WO2024161283A1

Abstract

The syngas production plant (1) comprises: one base frame (2) for resting on the ground; one pyrolysis reactor (3) associated with the base frame (2) and comprising one pyrolysis chamber (4) comprising: one inlet mouth (5) adapted to introduce the material to be treated; one outlet mouth (6) adapted to make the material to be gasified and the syngas; one gasification reactor (7) associated with the base frame (2) and comprising at least one gasification chamber (8) comprising: one inlet opening (9) adapted to introduce the material to be, the inlet opening (9) and the outlet mouth (6) being substantially coincident; one outlet opening (10) adapted to make the syngas escape.

Description

SYNGAS PRODUCTION PLANT

Technical Field

The present invention relates to a syngas production plant.

Background Art

Syngas production plants are technological plants in which biomass undergoes special chemical and physical treatment processes that result in the thermochemical conversion of biomass into a fuel gas, syngas.

Syngas is a synthesis gas mainly consisting of hydrogen, carbon monoxide, methane, carbon dioxide and nitrogen and is used as a fuel, e.g. in electric energy production plants.

Biomasses which are treated within syngas production plants can be different in nature and, e.g., can consist of municipal solid waste, i.e., waste products from the performance of human activities.

This makes it possible to recover municipal solid waste, which would still have to be disposed of, by converting it into a combustible product that can be used in other production processes.

Syngas production plants can, e.g., be differentiated according to the nature of the heat treatments to which biomass is subjected within it.

A first type of syngas production plant involves treating biomass through pyrolysis, which is a special process of thermochemical decomposition of a material of organic nature obtained by means of the application of heat and in the complete absence of oxygen.

Basically, during pyrolysis, heating of matter takes place under anoxic conditions in which the treated material undergoes the splitting of its original chemical bonds with the formation of simpler molecules.

Syngas production plants belonging to the first type comprise a pyrolysis reactor resting on the ground and provided with a pyrolysis chamber in which biomass is introduced in order to be pyrolyzed.

Biomass pyrolysis takes place at a temperature of between 400°C and 800°C and converts the treated material into fuel oils, tars and synthetic gaseous products, namely syngas. Syngas produced by a plant belonging to the first type has a medium to high heating value, that is, equal to about 4000 Kcal/nmc.

Syngas production plants belonging to the first type do, however, have some drawbacks which are mainly related to the poor thermodynamic efficiency of the pyrolysis reaction.

In fact, the thermodynamic efficiency of pyrolysis is around 70 percent, meaning that only 70 percent of the total amount of treated matter is transformed into syngas while the remaining 30 percent is transformed into the other waste products (oils and tars) which are difficult to recover.

Additionally, fuel oils and tars produced during pyrolysis are deposited on the inner walls of the pyrolysis chamber, leading to the formation of a layer made of oil and tar which can further lower the thermodynamic efficiency of the plant.

A second type of syngas production plant involves treating biomass through its gasification, which is a special process of thermochemical decomposition of a material of organic nature by means of the application of heat and of an oxidizing agent, e.g. air or water vapor.

Such syngas production plants comprise a gasification reactor resting on the ground and provided with a gasification chamber in which biomass is introduced in order to be gasified.

The gasification reactor also comprises a plurality of nozzles which are preferably associated with the lower portion of the gasification chamber and through which the oxidizing agent is introduced into the gasification chamber, thus triggering the combustion of the material to be gasified.

The thermochemical reaction enacted during gasification is identified as sub- stechiometric combustion, that is, poor in the oxidizing agent and occurs at a temperature of between 800°C and 900°C.

During gasification, organic material is transformed into a gaseous fuel (syngas) and an inert residue (char), which consists of a very fine powder, commonly called ash, the chemical composition of which varies greatly depending on the nature of the biomass from which it originated.

The inert residue represents a waste product which cannot be used as a fuel, but is chemically sterile and stable.

The thermodynamic efficiency of the thermochemical gasification reaction is equal to about 85 percent.

The syngas production plants belonging to the second type do, however, have some drawbacks which are mainly related to the particularly low heating value of the syngas that is obtained.

Precisely, the syngas produced by a plant belonging to the second type is equal to about 1100 Kcal/nmc.

Description of the Invention

The main aim of the present invention is to devise a syngas production plant which allows optimizing the thermodynamic efficiency compared with that of the plants of known type.

Another object of the present invention is to devise a syngas production plant which allows reducing the amount of fuel oils and tars generated within it.

A further object of the present invention is to devise a syngas production plant which allows obtaining syngas having a medium to high heating value.

Another object of the present invention is to devise a syngas production plant which allows the aforementioned drawbacks of the prior art to be overcome within the framework of a simple, rational, easy and effective to use, as well as cost-effective solution.

The aforementioned objects are achieved by this syngas production plant having the characteristics of claim 1.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive, embodiment of a syngas production plant, illustrated by way of an indicative, yet non-limiting example in the accompanying tables of drawings in which:

Figure 1 is an axonometric view of the plant according to the invention;

Figure 2 is a sectional view of the plant according to the invention;

Figure 3 is an exploded, partly cutaway and partly enlarged view of a plant gasification reactor according to the invention; Figure 4 is a sectional, partly enlarged view of the plant gasification reactor according to the invention wherein the mixing body is in the position of work;

Figure 5 is a sectional, partly enlarged view of the plant gasification reactor according to the invention wherein the mixing body is in the auxiliary position of work.

Embodiments of the Invention

With particular reference to these figures, reference numeral 1 globally denotes a syngas production plant.

The plant 1 comprises: at least one base frame 2 for resting on the ground; at least one pyrolysis reactor 3 associated with the base frame 2 and comprising at least one pyrolysis chamber 4 adapted to transform at least partly a material to be treated into a material to be gasified and into syngas and comprising: at least one inlet mouth 5 adapted to the introduction of the material to be treated into the pyrolysis chamber 4; at least one outlet mouth 6 adapted to the escape of the material to be gasified and of the syngas from the pyrolysis chamber 4; at least one gasification reactor 7 associated with the base frame 2 and comprising at least one gasification chamber 8 adapted to transform at least partly the material to be gasified coming from the pyrolysis reactor 3 into syngas and comprising: at least one inlet opening 9 adapted to introduce at least the material to be gasified into the gasification chamber 8, the inlet opening 9 and the outlet mouth 6 being substantially coincident; at least one outlet opening 10 adapted to make the syngas escape from the gasification chamber 8.

In the pyrolysis reactor 3, the material to be treated is treated through pyrolysis, which is heating under anoxic conditions through which the original chemical bonds of the organic molecules in the material to be treated are split with the formation of simpler molecules. Within the pyrolysis reactor 3, the material to be treated is heated and is brought to a temperature preferably of between 400°C and 800°C, or of between 500°C and 700°C, better still of between 550°C and 650°C.

The material to be gasified and syngas entering the gasification reactor 7 are found at the exit of the pyrolysis reactor 3.

The gasification reactor 7 is adapted to treat the material to be gasified through gasification, which is a special process of thermochemical decomposition by means of the application of heat and of an oxidizing agent.

The oxidizing agent is of the air or water vapor type and contains oxygen which, when it comes in contact with the heated material to be gasified, triggers the combustion thereof

The thermochemical reaction enacted during gasification is identified as sub- stechiometric combustion, that is, poor in the oxidizing agent.

The material to be gasified within the gasification reactor 7 is heated to a temperature preferably of between 700°C and 1000°C, or of between 750°C and 950°C, better still of between 800°C and 900°C.

During gasification, the organic material is transformed into syngas and into an inert residue, which consists of a very fine powder, commonly called ash, the chemical composition of which varies greatly depending on the nature of the biomass from which it originated.

The special technical expedient of subjecting the material to be treated first to a pyrolysis treatment and then to a gasification treatment allows significantly improving the thermodynamic efficiency of the plant 1 compared with what occurs in the prior art.

The thermodynamic efficiency of the plant 1 is equal to about 90%.

This means that about 90 percent of the total amount of the material to be treated which is introduced into the plant 1 is transformed into syngas.

Additionally, this results in a decrease in the amount of waste products coming out of the plant 1, which mainly consist of ash and activated carbon, i.e., inert and chemically stable products.

The fact that the material coming out of the pyrolysis reactor 3 actually constitutes the material at the input to the gasification reactor 7 allows limiting the amount of fuel oils and tars coming out of the plant 1 compared with the amount normally produced in a plant 1 treating the material only by pyrolysis.

Precisely, the fuel oils and tar coming out of the pyrolysis reactor 3 are subsequently split into simpler molecules in the gasification reactor 7.

In addition, the calorific value of the syngas coming out of the plant 1 is medium to high and is equal to about 2000 Kcal/nmc.

Within the scope of this disclosure, the components of the plant 1 are described according to an order substantially coincident with the direction of forward movement of the material to be treated within the plant 1.

Conveniently, the plant 1 comprises feeding means 11 adapted to supply the material to be treated to the pyrolysis reactor 3, the feeding means 11 being associated with the inlet mouth 5.

The feeding means 11 are operable to introduce the material to be treated within the pyrolysis chamber 4.

Preferably, the feeding means 11 comprise: at least a first feeding chamber 12 provided with at least one loading port 13 for the material to be treated and with an emptying port 14 for the material to be treated; at least a second feeding chamber 15 provided with at least one inlet port 16 associated with the emptying port 14 and with at least one outlet port 17 associated with the inlet mouth 5.

The first feeding chamber 12 comprises: a substantially hollow loading portion 18 and adapted to receive the material to be treated and comprising the loading port 13; and an emptying hopper 19 associated with the loading portion 18, comprising the emptying port 14 and adapted to receive the material to be treated from the loading portion 18 and to transfer it from the latter to the second feeding chamber 15.

Conveniently, the loading port 13 faces upwards so as to allow the insertion of the material to be treated into the first feeding chamber 12 by gravity. Conveniently, the feeding means 11 comprise first movement means 20, 21 associated with the first feeding chamber 12 and adapted to move the material to be treated from the loading port 13 to the emptying port 14.

The first movement means 20, 21 comprise: a first feeding screw 20 arranged within the first feeding chamber 12 and running longitudinally along a first axis of feeding Al arranged substantially parallel to the base wall of the loading portion 18; a first motor device 21 associated with the first feeding screw 20 and operable to make the first feeding screw 20 rotate around the first axis of feeding Al to displace the material to be gasified from the loading port 13 to the emptying port 14.

With particular reference to the embodiment shown in the figures, the first axis of feeding Al is oblique with respect to a substantially horizontal plane.

The first feeding chamber 12 is arranged on the top of the second feeding chamber 15.

The emptying port 14 faces downwards and the inlet port 16 faces upwards so that the material to be gasified is allowed to flow from the emptying hopper 19 to the second feeding chamber 15 by gravity.

Advantageously, the feeding means 11 comprise second movement means 22, 23 associated with the second feeding chamber 15 and adapted to move the material to be gasified from the inlet port 16 to the outlet port 17.

The second movement means 22, 23 comprise: a second feeding screw 22 arranged within the second feeding chamber 15 and running longitudinally along a second axis of feeding A2 arranged substantially parallel to the lower wall of the second feeding chamber 15; a second motor device 23 associated with the second feeding screw 22 and operable to make the second feeding screw 22 rotate around the second axis of feeding A2 to displace the material to be gasified from the inlet port 16 to the outlet port 17.

With particular reference to the embodiment shown in the figures, the second axis of feeding A2 is oblique with respect to a substantially horizontal plane. Advantageously, the plant 1 comprises at least one pressurization assembly 24 of the pyrolysis reactor 3 and of the gasification reactor 7 comprising: at least one pressurization device adapted to bring the pressure within the feeding chambers 12, 15 to a preset value of pressure above the atmospheric pressure;

- at least one opening/closing element 25 of the loading port 13 which is alternately positionable in an open position, to allow the introduction of the material to be treated into the first feeding chamber 12, and in a closed position;

- at least one opening/closing body 26 of the emptying port 14 and of the inlet port 16 which is alternately positionable in an opening configuration, to allow the material to be treated to be transferred from the first feeding chamber 12 to the second feeding chamber 15, and in a closing configuration.

The pressurization device, which is not shown in the figures for pure simplicity of representation, is, e.g., of the type of a compressor connected to the feeding chambers 12, 15 in a fluid-operated maimer.

The preset value of pressure is less than 1.5 bar.

Preferably, the preset value of pressure is 1.3 bar.

In other words, the pressurization device is operated to increase the pressure within the feeding chambers 12, 15 by 0.3 bar, since the feeding chambers 12, 15 are normally at the atmospheric pressure.

In this way, the pyrolysis reactor 3, which is connected through the inlet mouth 5 to the second feeding chamber 15, is overpressure compared with the external environment.

Likewise, the gasification reactor 7, which is connected through the inlet opening 9 to the pyrolysis reactor 3, is overpressure compared with the external environment.

In actual facts, during the operation of the plant 1, the pyrolysis reactor 3 and the gasification reactor 7 are at a pressure of 1.3 bar.

When the material to be treated is introduced into the first feeding chamber 12 the pressure inside the latter is equal to the atmospheric pressure. During this operation, the opening/closing body 26 is conveniently moved to the closing configuration in order to prevent the second feeding chamber 15 from entering in fluid-operated connection with the first feeding chamber 12 and undergoing a pressure drop.

In actual facts, the positioning of the opening/closing body 26 in the closing configuration allows keeping the second feeding chamber 15, and consequently the pyrolysis reactor 3 and the gasification reactor 7, at the preset value of pressure during the loading of the material to be treated into the first feeding chamber 12.

Before the opening/closing body 26 is placed in the opening configuration, in order to allow the material to be treated to pass from the first feeding chamber 12 to the second feeding chamber 15, the first feeding chamber 12 is to be returned to the preset value of pressure.

Therefore, the opening/closing element 25 is placed in the closing position and the pressurization device is operated to bring the pressure within the first feeding chamber 12 to the preset value of pressure.

When the pressure within the first feeding chamber 12 is again equal to the preset value of pressure, the opening/closing body 26 is positioned in the opening configuration in order to allow the material to be treated to be transferred from the first feeding chamber 12 to the second feeding chamber 15.

As previously mentioned, the material coming out of the feeding means 11 enters the pyrolysis reactor 3 and, specifically, the pyrolysis chamber 4.

With particular reference to the embodiment shown in the figures, the pyrolysis chamber 4 has a substantially cylindrical conformation and runs longitudinally along a main axis B, the inlet mouth 5 and the outlet mouth 6 being formed at the ends of the pyrolysis chamber 4.

The main axis B is arranged centrally to the inlet mouth 5 and to the outlet mouth 6.

In the particular embodiment shown in the figures, the main axis B is oblique with respect to a substantially horizontal plane.

The inlet mouth 5 is arranged at a lower elevation than the outlet mouth 6. As previously mentioned, the pyrolysis reactor 3 rests on the ground by interposition of the base frame 2.

Conveniently, the base frame 2 comprises a pair of supporting elements 27 arranged in a substantially vertical maimer and adapted to hold the pyrolysis reactor 3 from below.

Conveniently, the pyrolysis reactor 3 comprises transfer means 28 associated with the pyrolysis chamber 4 and adapted to move the material to be treated from the inlet mouth 5 to the outlet mouth 6.

Preferably, the transfer means 28 comprise at least one transfer feeding screw 29 arranged within the pyrolysis chamber 4, running along the main axis B and operable to move the material to be treated along the main axis B.

In actual facts, the material to be treated is moved by the transfer means 28 within the pyrolysis chamber 4 along the main axis B according to a direction of forward movement C substantially parallel to the main axis B and directed from the inlet mouth 5 to the outlet mouth 6.

Conveniently, the transfer means 28 comprise a motor associated with the transfer feeding screw 29 and operable to make the transfer feeding screw 29 rotate around the main axis B to displace the material to be treated according to the direction of forward movement C.

With particular reference to the embodiment shown in the figures, it can be seen that the main axis B is substantially coincident with the second axis of feeding A2.

In actual facts, the transfer feeding screw 29 is arranged coaxially with the second feeding screw 22.

More specifically, the transfer feeding screw 29 and the second feeding screw 22 are made in a single body piece.

Again, the driving motor of the transfer feeding screw 29 is coincident with the second motor device 23 which, when driven, moves both the second feeding screw 22 and the transfer feeding screw 29 in rotation, so as to create a continuous flow of material to be treated from the feeding means 11 to the inlet opening 9, passing through the pyrolysis reactor 3. Alternative embodiments of the plant 1 cannot however be ruled out wherein the feeding means 11 and the transfer means 28 can be made in a different maimer. For example, alternative embodiments of the plant 1 are provided wherein the transfer feeding screw 29 and the second feeding screw 22 are two separate bodies and/or are not coaxially arranged and/or are independently motorized.

As is familiar to the industry technician and as previously described, within the pyrolysis chamber 4 the material to be treated is heated and is brought to a temperature of between 400°C and 800°C.

Additionally, within the gasification chamber 8 the material to be gasified is heated to very high temperatures of between 800°C and 900°C.

The syngas coming out of the outlet opening 10, consequently, is also at particularly high temperatures, also of between 800°C and 900°C.

As is described below, the plant 1 provides for the use of the heat of the syngas coming out of the gasification reactor 7, which would be anyway lost into the external environment, to heat the pyrolysis chamber 4, thus avoiding the need to totally rely on auxiliary energy sources.

Conveniently, the plant 1 comprises at least one heating assembly 30 of the pyrolysis chamber 4 adapted to collect the syngas coming out of the outlet opening 10 and to distribute it to at least one outer wall 31 of the pyrolysis chamber 4.

The outer wall 31 laterally bounds the pyrolysis chamber 4, has a substantially tubular conformation and runs longitudinally along the main axis B.

Advantageously, the heating assembly 30 comprises at least one containment element 32 arranged around the outer wall 31 and adapted to define an interspace 33 with the latter, and at least one conveying duct 34 adapted to move the syngas from the outlet opening 10 to the interspace 33.

The containment element 32 has a substantially tubular development and runs longitudinally along the main axis B of the pyrolysis chamber 4.

The conveying duct 34 has a substantially tubular conformation and is positioned between the outlet opening 10 and the interspace 33 in a fluid-operated manner. The containment element 32 is provided with an inlet hole 35 adapted to allow the syngas to enter the interspace 33 and connected to the conveying duct 34.

It can be said that the heating assembly 30 so structured consists of a heat exchanger together with the pyrolysis chamber 4 and with the gasification reactor 7.

Precisely, the gasification reactor 7 consists of the body that gives up heat, the pyrolysis reactor 3 consists of the body that receives heat and the syngas consists of the fluid that transfers heat between the two bodies through the heating assembly 30.

Conveniently, the plant 1 comprises at least one picking duct 36 associated with the interspace 33 in a fluid-operated maimer and adapted to move the syngas from the interspace 33 to an external utilization unit.

The picking duct 36 has a substantially tubular conformation.

The containment element 32 is provided with an outlet hole 37 adapted to allow the syngas to escape from the interspace 33 and connected to the picking duct 36. The external utilization unit is, e.g., of the type of an endothermic motor which can be operated to produce electric energy.

In alternative embodiments, the external utilization unit may be a temporary syngas storage assembly.

With particular reference to the embodiment shown in the figures, it can be seen that the inlet hole 35 is arranged in the proximity of the outlet mouth 6 and the outlet hole 37 is arranged in the proximity of the inlet mouth 5.

In actual facts, the syngas enters the interspace 33 in the proximity of the outlet mouth 6 and from there it moves to the inlet mouth 5 according to a direction of movement D opposite the direction of forward movement C of the material to be gasified within the pyrolysis chamber 4.

As previously described, immediately downstream of the pyrolysis reactor 3 is arranged the gasification reactor 7 adapted to receive the material to be gasified directly from the pyrolysis reactor 3.

Conveniently, the base frame 2 comprises a plinth 38, resting on the ground, and at least one upright 39, associated at one end with the plinth 38, arranged in a substantially vertical manner and adapted to hold the gasification reactor 7 from below.

Preferably, the gasification chamber 8 has a substantially cylindrical conformation and runs longitudinally along a substantially vertical axis of development E.

Conveniently, the gasification chamber 8 comprises at least one side wall 40, the inlet opening 9 being formed on the side wall 40.

Specifically, the side wall 40 has a substantially tubular conformation and is arranged substantially vertically.

The gasification chamber 8 comprises a bottom wall 41 having a substantially flat development and arranged substantially horizontally.

The axis of development E is substantially orthogonal to the bottom wall 41.

The material to be gasified, once it enters the gasification chamber 8 through the inlet opening 9, is deposited by gravity on the bottom wall 41 arranging itself in several layers.

In the particular embodiment shown in the figures, the inlet opening 9 is formed where there is the lower half of the side wall 40 and is arranged in the proximity of the bottom wall 41.

The gasification chamber 8 comprises a top wall 42 having a substantially flat development and arranged substantially horizontally.

The axis of development E is substantially orthogonal to the top wall 42.

The outlet opening 10 is formed on the top wall 42 and faces upwards.

Conveniently, the gasification reactor 7 comprises a plurality of insufflation nozzles 42 associated with the side wall 40 and adapted to distribute at least one oxidizing agent into the gasification chamber 8.

Preferably, the oxidizing agent is composed of atmospheric air.

Alternatively, the oxidizing agent may be composed of water vapor.

Conveniently, the gasification reactor 7 comprises insufflation means 43 adapted to receive the oxidizing agent from an external source and to distribute it within the gasification chamber 8.

Preferably, the insufflation means 43 comprise: the insufflation nozzles 42; an insufflation channel 44 adapted to receive the oxidizing agent from the external source; an insufflation chamber 45 positioned between the insufflation channel 44 and the insufflation nozzles 42 in a fluid-operated maimer, adapted to receive the oxidizing agent coming from the insufflation channel 44 and to distribute it to the insufflation nozzles 42.

The insufflation chamber 45 is arranged within the gasification chamber 8 where the bottom wall 41 is located.

The insufflation chamber 45 has a substantially annular conformation and is developed around the axis of development E.

With particular reference to the embodiment shown in the figures, the insufflation nozzles 42 are arranged radially around the side wall 40 and within the insufflation chamber 45 and are allocated at the same elevation Q with respect to the ground.

Preferably, the elevation Q where the insufflation nozzles 42 are arranged is lower than the elevation where the inlet opening 9 is allocated.

Practically, the insufflation nozzles 42 are arranged below the inlet opening 9.

As is familiar to the industry technician and as has been previously described, the material to be gasified which is present within the gasification chamber 8 is heated to a temperature of between 800°C and 900°C.

The oxidizing agent is rich in oxygen and, therefore, as soon as contact occurs between oxygen and the hot material to be gasified, the combustion of the material to be gasified is triggered.

Conveniently, the gasification reactor 7 comprises at least one mixing body 46 arranged within the gasification chamber 8 and adapted to mix the material to be gasified.

The mixing body 46 is provided with at least one side surface 47 and is positionable in at least one position of work wherein the side surface 47 substantially face at least one of the insufflation nozzles 42.

In the context of the present disclosure, the verbal phrase “substantially face”, when referring to the positioning of the side surface 47 of the mixing body 46 with respect to the insufflation nozzles 42, should be understood to mean that at least one point of the side surface 47 is at the same elevation Q as the insufflation nozzles 42, with a tolerance of 5 cm.

In actual facts, when the mixing body 46 is in the position of work it is arranged where the insufflation nozzles 42 are located and is able to stir the material to be gasified placed there in order to improve the contact of the same with the oxidizing agent.

In detail, thanks to the mixing action enacted by the mixing body 46, the material to be gasified arranged in the proximity of the insufflation nozzles 42 (presumably already combusted) is moved away from the side wall 40 and pushed towards the center of the gasification chamber 8; at the same time, the material to be gasified arranged in the proximity of the center of the gasification chamber 8 (presumably not combusted) is moved away from the center and pushed towards the side wall 40, i.e., in contact with the oxidizing agent.

In this way, new material to be gasified can be continuously arranged in the proximity of the insufflation nozzles 42 so as to increase the amount of syngas produced.

At the same time, the amount of non-combusted gasification material can be reduced since much of the material to be gasified is brought in contact with the oxidizing agent.

Substantially, the mixing body 46 is adapted to spread the material to be gasified on the side wall 40.

Conveniently, the gasification reactor 7 comprises means for setting in rotation 48 which are adapted to rotate the mixing body 46 with respect to the gasification chamber 8 around a substantially vertical axis of movement F.

With particular reference to the embodiment shown in the figures, the means for setting in rotation 48 comprise a holding body 49, 50, onto which the mixing body 46 is attached, and an actuator device 51, associated with the holding body 49, 50 and operable to move the holding body 49, 50 in rotation around the axis of movement F.

Specifically, the holding body 49, 50 comprises a base element 49, having a substantially flat conformation and arranged substantially horizontally, and a rotational shaft 50 arranged substantially vertically and adapted to hold the base element 49 from below.

The rotational shaft 50 is associated with the actuator device 51 and is movable by the latter in rotation around the axis of movement F.

The fact of rotating the mixing body 46 with respect to the gasification chamber 8 allows the mixing body 46 to mix and stir the material to be gasified present in the gasification chamber 8 according to the previously described manner.

According to the preferred embodiment shown in the figures, the gasification reactor 7 comprises sliding means 52 adapted to make the mixing body 46 slide with respect to the gasification chamber 8 along the axis of movement F and to position the mixing body 46 in at least one auxiliary position of work separate from the position of work.

With particular reference to the embodiment shown in the figures, the sliding means 52 comprise:

- at least one guiding element 53, having a substantially elongated conformation and developing substantially parallel to the axis of movement F ;

- a slide element 54 associated with the guiding element 53 in a sliding maimer along the axis of movement F, the means for setting in rotation 48 being mounted on the slide element 54;

- a motorization device 55 associated with the slide element 54 and adapted to move the slide element 54 with respect to the guiding element 53 along the axis of movement F.

For pure representational simplicity, the motion transmission assembly between the motorization device 55 and the slide element 54 has not been shown in the figures.

For example, the motion transmission assembly consists of a plurality of mutually meshed gear wheels.

Thanks to the actuation of the sliding means 52, the mixing body 46 is lifted or lowered with respect to the bottom wall 41 of the gasification chamber 8. Precisely, when the mixing body 46 is in the auxiliary position of work, it is lifted with respect to when it is in the position of work.

As can be seen from Figure 5, when the mixing body 46 is in the auxiliary position of work, the side surface 47 does not face the insufflation nozzles 42, i.e., no point on the side surface 47 is at the same elevation Q as the insufflation nozzles 42.

In actual facts, when the mixing body 46 is in the auxiliary position of work it is not arranged where the insufflation nozzles 42 are located, but it is arranged at the top of the same.

When the mixing body 46 is moved from the configuration of work to the auxiliary configuration of work, it is able to displace the material to be treated from the bottom to the top while, when it is moved from the auxiliary configuration of work to the configuration of work, it is able to displace the material to be treated from the top to the bottom.

It is easy to appreciate that the special technical expedient of moving the mixing body 46 in a sliding maimer within the gasification chamber 8 allows improving the degree of stirring of the material to be treated by bringing it to react evenly with the oxidizing agent.

In actual facts, according to the preferred embodiment shown in the figures, the mixing body 46 is movable by shifting and in rotation with respect to the gasification chamber 8 along and around the axis of movement F.

Precisely, during the use of the plant 1, the mixing body 46 is simultaneously made to slide and rotate with respect to the gasification chamber 8, thus moving the material to be gasified in a swirling manner within the gasification chamber 8.

In this way, the oxidation of the material to be gasified is promoted and the combustion level thereof is improved.

Conveniently, the base element 49 comprises a protruding portion 49a arranged substantially horizontally and extending towards the inner surface of the gasification chamber 8 on which the material to be gasified tends to melt and to arrange itself in several layers.

During the rotation of the mixing body 46 and the sliding thereof along the axis of movement F, the protruding portion 49a moves in the proximity of the inner surface of the gasification chamber 8 going to scrape the molten and layered material.

In actual facts, the protruding portion 49a is adapted to keep clean the portion of the inner surface of the gasification chamber 8 close to which it flows.

Alternative embodiments of the plant 1 cannot, however, be ruled out, the mixing body 46 of which does not slide vertically with respect to the gasification chamber 8, i.e., is fixed in the position of work.

In this particular embodiment, the mixing body 46 is movable only in rotation with respect to the gasification chamber 8 around the axis of movement F.

Advantageously, the axis of movement F is substantially coincident with the axis of development E and the cross section of the mixing body 46 along a substantially horizontal plane is non-circular.

Preferably, the cross section of the mixing body 46 along a substantially horizontal plane is substantially rectangular.

In detail, as shown in the particular embodiment shown in the figures, the mixing body 46 has a substantially parallelepiped conformation.

Again, the mixing body 46 is made, at least partly, of refractory material.

As is well known to the industry technician, the refractory material is a special construction material which is able to withstand high temperatures for long periods without reacting chemically with the other materials with which it comes in contact.

Notoriously, very high temperatures are reached within the gasification chamber 8 and the fact of using a refractory material to make the mixing body 46 allows the latter to be heat-resistant for long periods without being damaged or deteriorated, making it durable.

The mixing body 46, during its use, is continuously brought in contact with the material to be treated and is stressed mechanically by the same during the mixing activity.

As is well known to the technician in the field, the refractory material has poor resistance to mechanical agents, but the special technical expedient of making the mixing body 46 so that it has a substantially parallelepiped conformation allows obtaining a compact, strong and durable mixing body 46, even if made of refractory material.

Advantageously, the gasification reactor 7 comprises purging means 56 adapted to remove the dirt deposited within the insufflation nozzles 42.

Preferably, the purging means 56 comprise a plurality of cleaning devices 57, each of which is provided with a fastening body 57a, associated with the side wall 40, and with a cleaning body 58, associated with the fastening body 57a in a movable maimer along an axis of sliding G.

In detail, the cleaning body 58 has a substantially elongated conformation and runs longitudinally along the axis of sliding G.

Again, the fastening body 57a defines a substantially circular sliding seat into which the cleaning body 58 is fitted in a sliding manner.

Each cleaning device 57, as a result of the relevant sliding along the axis of sliding G, is movable between an insertion configuration, wherein it is inserted within a relevant insufflation nozzle 42, and an extracted configuration, wherein it is partly extracted from the same insufflation nozzle 42.

In Figure 3, all cleaning devices 57 are allocated in the insertion configuration except for one cleaning device 57, which is in the extracted configuration.

The movement of the cleaning device 57 between the insertion configuration and the extracted configuration enables the frictional cleaning of the inner surface of the insufflation nozzle 42 with which it is associated.

According to the preferred embodiment shown in the figures, the movement of the cleaning device between the insertion configuration and the extracted configuration is done manually.

Conveniently, each cleaning body 58 is provided with a relevant gripping handle which can be grasped by an operator during the movement of the cleaning device 57 between the insertion configuration and the extracted configuration.

In alternative embodiments, not shown in the figures, the movement of the cleaning device 57 between the insertion configuration and the extracted configuration is automated. In such a case, the purging means 56 also comprise a motor assembly which can be operated to move each cleaning body 58 in a sliding maimer with respect to the relevant fastening body 57a.

Conveniently, the gasification chamber 8 comprises: at least a first gasification portion 59 adapted to transform the material to be gasified into syngas, the mixing body 46 and the insufflation nozzles 42 being associated with the first gasification portion 59; at least a second gasification portion 60 arranged above the first gasification portion 59 and adapted to perform a cracking treatment on the syngas produced in the first gasification portion 59, the outlet opening 10 being associated with the second gasification portion 60; at least one connecting element 61 located between the gasification portions 59, 60 and adapted to transfer the syngas from the first gasification portion 59 to the second gasification portion 60; activation means 62 associated with at least one of the gasification portions 59, 60 and adapted to activate a cracking reaction on the syngas present in the second gasification portion 60.

The first gasification portion 59 is bounded by the bottom wall 41 below, laterally by the lower half of the side wall 40 and is open at the top.

The second gasification portion 60 is open below, is laterally bounded by the upper half of the side wall 40 and bounded by the top wall 42 at the top.

The connecting element 61 has a substantially flat and substantially circular conformation and is positioned between the gasification portions 59, 60.

The connecting element 61 is substantially orthogonal to the axis of development E.

The connecting element 61 is provided with a connecting hole 63 which is adapted to allow the syngas to flow from the first gasification portion 59 to the second gasification portion 60.

The connecting hole 63 is substantially circular and the axis of development E is arranged centrally to the connecting hole 63.

With particular reference to the embodiment shown in the figures, the activation means 62 are operable to thermally activate the cracking reaction on the syngas present in the second gasification portion 60.

Precisely, the activation means 62 comprise a dispensing channel 64 adapted to distribute in the gasification portion 59, 60 with which it is associated, water vapor that is split into hydrogen and oxygen, thus releasing heat.

This heat is used to treat by cracking the syngas present in the second gasification portion 60.

Through the cracking reaction, the molecules of heavy paraffinic hydrocarbons present in the syngas can be completely split into light paraffinic hydrocarbons. According to the preferred embodiment shown in the figures, the dispensing channel 64 is associated with the first gasification portion 59 and adapted to introduce water vapor where there is the connecting hole 63.

Alternative embodiments of the plant 1 cannot, however, be ruled out wherein the dispensing channel 64 is associated with the second gasification portion 60.

Still, alternative embodiments cannot however be ruled out of the plant 1 wherein the activation means 62 may be different and, e.g., comprise a catalyst.

Advantageously, the gasification reactor 7 comprises collection means 65 of at least one waste product deposited on the bottom of the gasification chamber 8, the collection means 65 being associated with the gasification chamber 8.

The waste product is the fraction of the material to be treated that was not involved either in the pyrolysis reaction or in the gasification reaction and has been deposited on the bottom wall 41.

The waste product is, e.g., composed of inert residue (char), which consists of a very fine powder, commonly referred to as ash, the chemical composition of which varies greatly depending on the nature of the biomass from which it originated.

With particular reference to the embodiment shown in the figures, the collection means 65 comprise a receding feeding screw, not shown in the figures, associated with the bottom wall 41 and operable by a relevant motor to move the waste product away from the same bottom wall 41.

The operation of the plant 1 according to the invention is as follows. The material to be treated is introduced into the pyrolysis reactor 3 through the feeding means 11.

Specifically, the material to be treated is initially introduced into the first feeding chamber 12 through the loading port 13 and moved towards the emptying port 14 through the first movement means 20, 21.

Next, the material to be treated comes out of the emptying port 14 and falls by gravity into the second feeding chamber 15 through the inlet port 16.

Then, the material to be treated is displaced from the inlet port 16 to the outlet port 17 through the second movement means 22, 23.

At this point, the material to be treated enters the pyrolysis reactor 3 through the inlet mouth 5 and is moved towards the outlet mouth 6 thanks to the activation of the transfer means 28.

As the material to be treated is displaced within the pyrolysis chamber 4, it undergoes a pyrolysis treatment that transforms it into material to be gasified and into syngas.

Precisely, a pyrolysis reaction can be carried out on the material to be treated since the pyrolysis chamber is heated through the heating assembly 30 that heats the outer wall 31 of the pyrolysis chamber 4 through the syngas coming out of the gasification reactor 7.

The material to be gasified and syngas come out of the pyrolysis reactor 3 through the outlet mouth 6 and enter the gasification reactor 7 where the material to be gasified is treated and transformed into syngas.

Within the gasification reactor 7 the material to be gasified is heated and is partly burned thanks to the insufflation of an oxidizing agent within the gasification chamber 8.

The mixing body 46 is moved in order to promote the mixing of the material to be gasified and in order to allow it to be oxidized as evenly as possible.

Next, the syngas produced into the gasification reactor feeds the heating assembly 30, as described above, and is then sent to an external utilization unit.

It has in practice been ascertained that the described invention achieves the intended objects. First of all, the special technical expedient of subjecting the material to be treated first to a pyrolysis treatment and then to a gasification treatment allows the thermodynamic efficiency of the plant to be greatly improved with respect to what occurs in the prior art. Precisely, the thermodynamic efficiency of the plant according to the invention is around 95 percent.

Secondly, the plant according to the invention allows for a reduction in the amount of fuel oils and tars generated internally since the fuel oils and tar coming out of the pyrolysis reactor are subsequently split into simpler molecules within the gasification reactor.

Additionally, this results in a decrease in the amount of waste products coming out of the plant, which mainly consist of ash and activated carbon, i.e., inert and chemically stable products.

Still, the plant according to the invention allows obtaining syngas with a heating value from medium to high which, specifically, turns out to be equal to about 2000 Kcal/nmc.

Claims

1) Syngas production plant (1), characterized by the fact that it comprises: at least one base frame (2) for resting on the ground; at least one pyrolysis reactor (3) associated with said base frame (2) and comprising at least one pyrolysis chamber (4) adapted to transform at least partly a material to be treated into a material to be gasified and into syngas and comprising: at least one inlet mouth (5) adapted to introduce said material to be treated into said pyrolysis chamber (4); at least one outlet mouth (6) adapted to make said material to be gasified and said syngas escape from said pyrolysis chamber (4); at least one gasification reactor (7) associated with said base frame (2) and comprising at least one gasification chamber (8) adapted to transform at least partly said material to be gasified coming from said pyrolysis reactor (3) into syngas and comprising: at least one inlet opening (9) adapted to introduce at least said material to be gasified into said gasification chamber (8), said inlet opening (9) and said outlet mouth (6) being substantially coincident; at least one outlet opening (10) adapted to make said syngas escape from said gasification chamber (8).

2) Plant (1) according to claim 1, characterized by the fact that it comprises at least one heating assembly (30) of said pyrolysis chamber (4) which is adapted to collect said syngas escaping from said outlet opening (10) and to distribute it on at least one outer wall (31) of said pyrolysis chamber (4).

3) Plant (1) according to one or more of the preceding claims, characterized by the fact that said heating assembly (30) comprises at least one containment element (32), arranged around said outer wall (31) and adapted to define with the latter an interspace (33), and at least one conveying duct (34) adapted to move said syngas from said outlet opening (10) to said interspace (33).

4) Plant (1) according to one or more of the preceding claims, characterized by the fact that it comprises at least one picking duct (36) associated with said interspace (33) in a fluid-operated manner and adapted to move said syngas from said interspace (33) to an external unit of utilization.

5) Plant (1) according to one or more of the preceding claims, characterized by the fact that said pyrolysis reactor (3) comprises transfer means (28) associated with said pyrolysis chamber (4) and adapted to move said material to be treated from said inlet mouth (5) to said outlet mouth (6).

6) Plant (1) according to one or more of the preceding claims, characterized by the fact that said pyrolysis chamber (4) has a substantially cylindrical conformation and develops longitudinally along a main axis (B), said inlet mouth (5) and said outlet mouth (6) being formed at the ends of said pyrolysis chamber (4).

7) Plant (1) according to claims 5 and 6, characterized by the fact that said transfer means (28) comprise at least one transfer feeding screw (29) arranged within said pyrolysis chamber (4), developing along said main axis (B) and operable to move said material to be treated along said main axis (B).

8) Plant (1) according to one or more of the preceding claims, characterized by the fact that it comprises feeding means (11) adapted to supply said material to be treated to said pyrolysis reactor (3), said feeding means (11) being associated with said inlet mouth (5).

9) Plant (1) according to one or more of the preceding claims, characterized by the fact that said feeding means (11) comprise: at least a first feeding chamber (12) provided with at least one loading port (13) of said material to be treated and with one emptying port (14) of said material to be treated; at least a second feeding chamber (15) provided with at least one inlet port (16) associated with said emptying port (14) and with at least one outlet port (17) associated with said inlet mouth (5).

10) Plant (1) according to one or more of the preceding claims, characterized by the fact that it comprises at least one pressurization assembly (24) of said pyrolysis reactor (3) and of said gasification reactor (7) comprising: at least one pressurization device adapted to bring the pressure inside said feeding chambers (12, 15) to a predetermined value of pressure above the atmospheric pressure; at least one opening/closing element (25) of said loading port (13) which is alternately positionable in an open position, to allow the introduction of said material to be treated into said first feeding chamber (12), and in a closed position; at least one opening/closing body (26) of said emptying port (14) and of said inlet port (16) which is alternately positionable in an opening configuration, to allow the transfer of said material to be treated from said first feeding chamber (12) to said second feeding chamber (15), and in a closing configuration.