WO2019138339A1

WO2019138339A1 - Biomass pyrogasification plant

Info

Publication number: WO2019138339A1
Application number: PCT/IB2019/050162
Authority: WO
Inventors: Daniele LAZZARI; Antonio NENNA
Original assignee: Lazzari Daniele; Nenna Antonio
Priority date: 2018-01-11
Filing date: 2019-01-09
Publication date: 2019-07-18
Also published as: IT201800000755A1

Abstract

A pyro-gasification plant comprising the following components: at least one system for storing and feeding chip material (1), at least one pyro-gasifier (2), at least one system for recovering the gas flowing out of said pyro- gasifier, at least one power cogeneration unit (3). A control system (4) is also provided, which control system (4) is in communication with one or more of said components, such that said control system (4) manages the operation of said one or more components, a network of sensors being further positioned in the one or more components and in communication with said control system (4).

Description

BIOMASS PYROGASIFICATION PLANT

The present invention relates to a pyro-gasification plant comprising:

- at least one system for storing and feeding chip material,

- at least one pyro-gasifier,

- at least one system for recovering the gas flowing out of said pyro- gasifier,

- at least one power cogeneration unit.

Wood biomass pyro-gasification has been known for centuries and has been used for many decades.

Nevertheless, in prior art plants, wood gasification, which occurs through pyrolysis, causes massive generation of soot and tar.

Furthermore, currently available wood biomass is characterized by highly variable compositions, moisture and impurities.

Such variability is reflected in the pyrolysis process and accordingly affects efficiency, and this problem can be only solved with advanced biomass selection and drying systems, which are inconveniently expensive and inefficient.

Therefore, the pyro-gasification reaction is not complete and generates a syngas that has variable calorific value and volumetric flow and, even worse, is polluted by CHAR and TAR burning residues which are converted to tar with condensing steam and quickly deteriorate the plant, which thus requires frequent part replacement and maintenance, or may even be forced to shutdown.

As mentioned above, prior art plants have attempted to mitigate the variability of the pyro-gasification reaction by selecting the chip material for higher yield. This affects the flexibility of plants, which cannot use any type of chip material, and especially are not allowed to use low-zero cost local renewable sources such as carpentry waste, forestry waste, etc.

Therefore, there exists a need, yet unfulfilled in prior art plants, for a plant that can implement a pyro-gasification process in which the flexibility obtained by the possibility of using wood biomass of various grades and types, is combined with efficiency, as the syngas (and hence power) yield from wood biomass is constantly maximized as well as environment-friendliness, with minimized waste and emission generation.

The present invention fulfills the above purposes by providing a plant as discussed hereinbefore, which includes a control system in communication with one or more of said components, such that the control system will manage the operation of one or more components.

A network of sensors is further positioned in the one or more components and in communication with the control system.

The provision of the control system allows the plant to have a fully automatized PLC-based computer-assisted operation, and allows the operator to only receive control functions. All the flows are regulated in an entirely automatic manner to always use optimal parameters and generate the desired electric power.

Therefore, the plant of the present invention has the purpose to produce electricity and heat from wood biomass pyro-gasification, to thereby provide the best solution for treatment and exploitation of renewable sources, such as wood biomass.

Particularly, this technology uses virgin wood chips to produce combustible gas, i.e. syngas, by thermochemical conversion of wood. After a cleaning step, the output gas supplies a cogeneration unit, and power is thus produced.

As described below in further detail, the residual heat from the gasifier and the internal combustion engine is decoupled from the process and separately used for civil and industrial purposes.

Finally, the present invention has the object to provide a plant that is flexible, i.e. able to ensure pyro-gasification of any wood biomass in any state, and efficient, i.e. able to maximize both thermal power and syngas yield from biomass, while reducing pollutants and emissions and exploiting and adding value to process waste.

It will be appreciated that the general principle of the invention is the ability to monitor the entire process, from biomass storage to power generation, using the control system.

Generally, the invention is not limited to particular types of components, and may be indeed adapted to any plant system, and scaled according to target powers, from small-scale plants (typically with pyro- gasification units of about 10-20 kWe) to large-scale plants (typically with pyro-gasification units of about 400-500 kWe).

The invention also relates to a biomass pyro-gasifier comprising an outer body that defines an inner chamber.

The inner chamber has at least one drying chamber, designed to receive the biomass, and at least one reaction chamber.

The reaction chamber has means for igniting a flame for biomass combustion.

Furthermore, the drying chamber and/or the reaction chamber are at least partially surrounded by a thermal flywheel.

It will be appreciated from the exemplary embodiments herein that the pyro-gasifier and the control system of the present invention are self- sufficient in terms of syngas production and may be connected to any upstream biomass storage/feeding system and to any downstream power cogeneration system.

Optional features of the inventive plant may be found in the attached dependent claims, which form an integral part of the present disclosure.

Also, these and other features and advantages of the present invention will appear more clearly from the following description of a few embodiments, illustrated in the annexed drawings, in which:

Fig. 1 shows an exemplary schematic view of the plant of the present invention according to a possible embodiment; Figures 2a and 2b show two sectional schematic view of an exemplary pyro-gasifier that is part of the system of the present invention, according to a possible embodiment.

It shall be noted that the figures annexed to the present application depict certain embodiments of the plant of the present invention, to provide an improved understanding of its advantages and the described characteristics.

Therefore, these embodiments shall be intended by way of illustration and without limitation to the inventive concept of the present invention, which consists in providing a fully automated and highly safe and efficient wood biomass-based pyro-gasification plant, which is designed to optimize efficiency and reduce waste.

Particularly, Figure 1 shows an exemplary schematic illustration of one embodiment of the system of the present invention.

The plant is divided into four functional blocks:

a system for storing and feeding chip material 1 , namely woody biomass,

a gasifier and a system for recovering the gas that flows out of said pyro-gasifier 2,

an electrical power cogeneration unit 3,

a control system 4.

As mentioned above, the control system 4 supervises the operation of all the components of the plant, via a network of sensors installed in the various components, which will be hereinafter described in detail, according to a possible embodiment.

Before reading the description of the individual components, it shall be noted that the particular configuration of the plant and construction of its components, allows the use of any type of wood biomass.

In particular ligno-cellulosic biomass with a moisture content of up to 50%.

As the biomass grade and moisture change, the plant of the present invention maintains a constant flow of output gas, by accelerating or reducing the biomass consumption. The feeding and storing system 1 preferably comprises a container 1 1 which is designed to receive the chip material.

The container 1 1 comprises a movable chip-displacing floor, which pushes the material toward means for transferring the material to the gasifier.

These transfer means preferably consist of a belt conveyor 12.

The control system 4 has the purpose of activating/deactivating the movable floor of the container 1 1 and the conveyor belt 12, according to the data detected by a network of sensors, which form a system for monitoring the container 1 1 and the conveyor 12.

Particularly, the material is placed in a special metal storage container 1 1 .

Advantageously the storage container 1 1 has a net capacity of about 27 cubic meters and is dimensioned to contain approximately 8 tonnes of chips.

A sliding cover allows dry storage of the chips and loading thereof using conventional systems. The container 1 1 has a movable floor which moves forward to deliver the chips to the conveyor 12.

The container 1 1 is also equipped with a system for monitoring the minimum-maximum level which notifies the loading state of the container 1 1 to the control system.

The container 1 1 also has a system for monitoring the presence of the chips at the interface with the conveyor 12. This system notifies the presence or absence of chips to the control system 4, which accordingly stops or actuates the movement to the movable floor: this will ensure that chips will be always provided on the conveyor 12.

The container 1 1 is at ambient temperature and pressure.

The chips are delivered from the storage container 1 1 , via the movable floor, to a belt conveyor 12 with metal boxes which moves the chips to the internal distribution and drying system of the pyro-gasifier.

The belt conveyor 12 has no accessible openings, such that the chips will be held in dry conditions all along the path. The conveyor 12 also allows the chip material to cover the height difference between the storage system and the gasifier 2.

In one embodiment, such height difference is 5.8 meters, the conveyor 12 has a speed of 4 meters/minute and a capacity of 0.115 cubic meters/minute.

The belt conveyor 12 is equipped with a system for monitoring the minimum/maximum level, which informs the control system 4 about the loading state at the interface with the gasifier 2: this system notifies the chips state to the control system 4, which accordingly stops or actuates the movement to the belt conveyor 12.

This will ensure that chips will be always input to the gasifier 2

The belt conveyor 12 also has a system for monitoring the passage of chips on the belt conveyor 12. This system notifies the presence or absence of chips to the control system 4, which accordingly stops or actuates the movement to the movable floor of the container 11.

This will ensure that chips will be always input to the belt conveyor

12

The feeding system 11 is at ambient temperature and pressure.

The chip material that comes out of the conveyor 12 is introduced into the pyro-gasifier 2, which is the main core of the plant, a possible embodiment whereof is shown in Figures 2a and 2b.

The pyro-gasifier comprises a drying chamber 21 and a reaction chamber 22.

The drying chamber 21 is in communication with the reaction chamber 22 via mechanical means 212 for distributing the chip material.

The activation/deactivation of these mechanical means allows the chip material to move from the drying chamber 21 to the reaction chamber 22.

Furthermore, the gasifier comprises a pump unit for introducing combustion air (referenced 23 in Figure 1 ), which unit pumps combustion air through an inlet into the reaction chamber 22, and a suction pump unit for extracting the output gas through an outlet of the reaction chamber 22, a delivery valve being provided for measuring and controlling the flow of input air and a suction valve being provided for measuring and controlling the flow of extracted gas, said valves being connected to the control system 4.

Still referring to Figures 2a and 2b, the pyro-gasifier has a thermal flywheel, consisting of a ceramic mass overheated by the furnace, which allows full pyro-gasification of the chips before reaching the furnace.

Particularly referring to Figure 2, both the drying chamber 21 and the reaction chamber 22, are at least partially surrounded by said thermal flywheel, 210 and 220 respectively.

Preferably the furnace of pyro-gasifier produces temperatures above 1000°C, which allow chip waste incineration and generates the thermal power required for its operation.

With this temperature, the furnace overheats a number of ceramic catalysts 24 through which syngas is forced to circulate, to be purified from waste elements, such as CFIAR and TAR, which will be recombined to produce additional syngas, thereby improving efficiency and reducing pollutants.

In the variant of the figures, the catalysts 24, consisting of ceramic elements, are also at least partially surrounded by a thermal flywheel 240.

The wood biomass is treated and exploited by pyro-gasification in the pyro-gasifier.

The pyro-gasifier is mounted to a load-bearing steel structure 20 which is adapted to support all of the components, to allow access for inspection/maintenance and to impart weather protection. This structure 20 is also entirely open, without walls or casings, thereby leaving the components exposed. The parts of the pyro-gasifier are insulated to minimize losses and providing protection to operators.

The chips fed by the belt conveyor 12 flow into the hopper 201 of the pyro-gasifier which uses a motor-driven auger 202 to meter the biomass fed to the drying chamber 21 in the gasification reactor. Immediately before the chips come out from belt conveyor 12 and enter the hopper 201 , the moisture of the chips is monitored and transmitted to the control system 4, which will increase or decrease the time of permanence of the chips in the drying chamber 21 to ensure that they will reach the reaction chamber 22 in optimal conditions.

The drying chamber 21 distributes a constant amount of biomass, which is adjusted by the level sensors for controlling the filling state of the drying chamber 21 and the load in the reaction chamber 22. This cycle is controlled by the achievement of the maximum filling level in the reaction chamber 22.

A mechanical system designed to control such level activates and deactivates a position sensor depending on whether biomass is found at that level: this sensor generates a stop signal to stop the whole feeding chain (belt conveyor 12 and movable floor of the container 1 1 ) and is reactivated to start it again.

The feeding conditions may be deemed to be instantaneously discontinuous because, once the pyro-gasifier is loaded, it takes some time to consume an amount of biomass required to reactivate the mechanical level control system and to restart the loading cycle. Nevertheless, when considering operation over several hours, the mean flow of the biomass to the reaction chamber 22 is constant. The mean flow of the biomass sent to the reaction chamber 22 is given by the consumption of biomass in the pyro-gasifier.

Preferably the movement from the hopper 201 to the drying chamber 21 occurs through a passage that is closed when no chips move from the hopper 201 to the drying chamber 21 . In the drying chamber 21 the temperature is about 150-200°C, and the pressure is ambient pressure. Although the hopper 201 is insulated, as it is next to the drying chamber 21 , its temperature reaches 40/50°C, and the pressure is ambient pressure.

In the pyro-gasifier, gas is produced without pressure in a downdraft through the drying, pyrolysis, oxidation and reduction stages.

Gasification is a thermal biomass treatment process. Unlike incineration or normal biomass combustion, a smaller amount of oxygen supply is required in gasification. If the reaction were conducted with no oxygen pyrolysis would occur, hence gasification uses an amount of oxygen to obtain an amount of heat that will maintain the required temperature of the process.

The dry chips 21 leave the drying chamber 21 and move downwards toward the reaction chamber 22 in which an empty space has been left by the previous chips that have been converted to ashes. The process temperature in the reaction chamber 22 is typically above 750°C (preferably 900°C - 1200°C) and the gas is obtained through a series of chemical reactions before full combustion of spent chips.

Syngas is produced at high temperatures and subsequently cooled in the cleaning sections, but it is above ambient temperature throughout the plant, whereby it causes a further upward thrust in case of leakage. Two gases (CH4 and H2) are lighter than air, whereas CO (and N2) have about the same specific weight as air.

Based on tests carried out on the inventive plant, at the end of the process, the only remaining residue is ash, which is about 3% of the biomass that was fed. Ash is almost entirely composed of inert mineral material with few traces of coal.

During the process, the water content of the input wood, as it passes through charcoal, is reduced to hydrogen (H2) whereas the oxygen from water immediately aggregates with the carbon of the charcoal thereby producing carbon monoxide (CO), both merging into syngas. The process does not produce water.

In a preferred embodiment, the gasifier is composed of a container 200 which is about 2.5 meters high, with a 4-layer inner lining 4 made of a refractory and insulating material.

Process combustion air is forced into the reaction chamber 22, through a motorized pump unit, to 3 different reaction zones (i.e. pyrolysis, oxidation and reduction zones) according to the geometry of the reaction chamber and is controlled by air diffusers which allow it to be preheated as it circulates in the reaction chamber. Combustion air circulates at ambient temperature and pressure but in the last section, which is already located in the gasifier, it reaches a temperature of about 250-300°C. The chip load is placed on a grid 27 which allows ashes to fall and safely removed through a conduit located on the bottom of the pyro- gasifier. Ash is removed through the a rotatingly closable opening on the bottom of the pyro-gasifier, which opens at regular time intervals regulated by the control system 4 according to the amount of biomass that has been fed. Output ashes are at a temperature of about 50-60°C and at ambient pressure.

A safety device is mounted to the top of the pyro-gasifier, and during start-up or shut-down or in case of malfunctions or black-out, it provides communication between the reaction chamber 22 and the outside environment via a chimney 203 which allows emission of flue or residual gas to the atmosphere.

A device is also provided for opening/closing the chimney, which is only closed when there is an electric signal is and automatically opens the chimney 203 in case of black-out. This is a fail-safe feature because, in case of power failure, combustion air delivery and gas suction are closed (the pump units are deactivated) and non-return valves are used to evacuate any emissions from the extinguishing chips through the chimney 203.

As mentioned above, the syngas is extracted through a motorized pump unit which sends the syngas to the cleaning circuit.

The syngas produced in the reaction chamber 22 flows into the catalyst system 24 where it is "cleaned", with waste condensate being extracted therefrom and discharged through the outlet 242.

The clean syngas is extracted through the outlet 28.

A shut-off valve is located directly behind the outlet 28

As mentioned above, the crude, powder-saturated syngas (with carbon micropowder) that flows out of the reaction chamber 22 is cooled and purified through a labyrinth system 261 , integrated in the pyro- gasifier, which can reduce the gas temperature from about 900°C to about 50°C.

This thermal drop allows gas condensate to extract 99% of powder (carbon micropowder) contained therein. The condensate so obtained is removed through a motorized pump unit which is actuated at predetermined intervals by the control system 4 and is discharged through the outlet 242. The circuit that creates the thermal drop also allows recovery of the thermal energy of the gas through the pump system and a heat exchanger.

This circuit is particularly composed of a turbulator system 26 with turbulators arranged around the two chambers 21 and 22, which cause the fall/detachment of the accumulated micropowder at regular intervals, and of a heat exchanger system 25.

The thermal energy is available for the thermal cycle of the heating or air conditioning system.

In a possible embodiment, as shown in Figure 2b, means 27 for generating a flame are provided at the grid 27, and preferably consist of an electric resistor that automatically extends and retracts to ignite a biomass and start the pyro-gasifier.

This resistor is also preferably operated by the control system 4.

The ashes resulting from the biomass combustion process may be ejected through a waste circuit 272, below the grid 27.

As described above, combustion air is introduced into the pyro- gasifier through the inlet pump unit which comprises a motorized pump unit and stainless steel pipes. A non-return clapet valve is provided along the main pipe, which extends from the pump unit to the pyro-gasifier, and only allows the passage of air toward the pyro-gasifier and prevents backward gas or flue gas leakage, in case of plant shutdown/blockage/black-out.

A downstream motorized valve, chokes the air flow under the control of the control system, to thereby control the chip combustion in the reaction chamber. A multi-function meter sends the instantaneous values of temperature, pressure, mass flow rate and volume flow rate of combustion air in real time to the control system 4. According to a variant embodiment, the combustion air pump is coupled to the syngas extraction pump via a mechanical direct drive shaft. This peculiar configuration allows coupled variation of syngas delivery and suction more quickly and stably than with PLC-controlled “electric axes”. Combustion air circulates at ambient temperature and pressure but in the last section, which is already located in the gasifier, it reaches a temperature of about 250-300°C.

As described above, the output gas (syngas) of the gasifier, already cooled to about 50°C and already purified from approximately 99% of its powder (carbon micropowder) is extracted through a motorized pump unit and is sent, via stainless steel pipes, to the purification circuit.

Before circulating through a suction unit, the extracted gas is conveyed through a passive filter, composed of a porous stainless steel diaphragm; here the moisture contained in the gas further condenses and helps to remove part of residual impurities.

In this section, upstream from the suction unit, gas temperature is about 50°C, and pressure is about 923 hPa. The condensate so obtained is removed through a second motorized pump unit which is actuated at predetermined intervals by the control system 4.

Downstream from the suction unit, the gas is conveyed to the active filter system which ensures final gas purification. The active filter system is composed of a chilled-water refrigerator and a centrifugal impurity and condensate separating system. In this section, at the output of the active filter, gas temperature is about 30 °C, and pressure is about 1 123 hPa. The condensate so obtained is removed through two automatic condensate discharging units.

A circuit with a vacuum breaker and a bypass circuit of the suction unit are provided in the two duct sections immediately downstream and upstream from the motorized suction pump unit.

The vacuum breaker prevents negative pressures above design negative pressure from building up upstream from the suction pump unit, and the bypass circuit, equipped with a non-return clapet valve allows direct suction of the gas, through the ramp, into the cogeneration unit, as described later, in case of the suction pump unit. In addition, the gas pipe is equipped with a motorized valve, operated by the control system 4, that can be used to exclude the active filter system during power-up of the plant, and switching it directly to the flare mode.

The purified gas, at the output of the purification system, is conveyed to the cogenerator 3 via stainless steel pipes: the pipe section of the flare circuit branches off the main pipe at the cogenerator.

The flare circuit is composed of a relief valve, a pressure switch, a temperature probe K and a step-up transformer. The relief valve directs the gas to the flare when pressure exceeds about 1 123 hPa: this can occur whenever the cogenerator is inactive, but the gasifier does not need to be shut down, at plant start-up, in case of malfunctioning and blockage of the cogenerator, during blackouts or maintenance of the cogenerator.

When the gas is directed to the flare, the pressure switch, which is operated by the control system, ignites the gas in flare mode by the step- up transformer (electric spark). The temperature probe K, operated by the control system ensures that the gas is actually ignited: if it is not, after a few ignition attempts, the control system finally shuts down the gasifier. Conversely, when the flare is ignited (probe K) the control system, after a predetermined period, such as 30 minutes, reduces the biomass and combustion air flows and runs the pyro-gasifier in idle mode.

The ramp pipe is also equipped with a multi-function meter which sends the instantaneous values of temperature, pressure, mass flow rate and volume flow rate of the gas in real time to the control system 4. The gas, available to the cogenerator 3, is at a temperature of about 30°C, and at a pressure is about 1 123 hPa.

It shall be further noted that the gasifier is equipped with a gas cleaning system, which can reduce gas temperature from about 900°C to about 50°C.

In order to provide this thermal drop, the pyro-gasifier is equipped with a heat-exchanging system which uses a free cooler. The system is equipped with two recirculation pumps, a 80-Liter expansion chamber, a cooling water loading circuit and control devices (ISPEL): a manual reset pressure switch, a flow switch and a manual reset temperature control. The temperature of the cooling water as it flows out of the gasifier is about 90°C, and about 50°C as it flows into it.

This thermal energy is available for the thermal cycle of the heating or air conditioning system (heat pump). A motorized diverter valve, operated by the control system, can direct the thermal energy to (civil and/or industrial) units. A calorie meter indicates the power circulating in the cogeneration system of the gasifier. The thermal energy that can be recovered from the gasifier is about 200 kWt.

The interactions of the control system 4 with the various parts of the plant will be now described.

As shown in figure 1 , the control system 4 may be housed in a standard 40-feet (12 m) steel shelter container.

The control system 4 manages the entire biomass exploitation process, from the time of arrival of the chips to the time of electric and thermal energy feed into the network.

Namely, the control system 4 operates:

- the chip container 1 1 : if the latter is not filled, it triggers an alarm and later shuts down the plant. The uptime of the pyro-gasifier from the time of the alarm signal is about 1 hour, then the control system shuts down the plant.

- the chip feed via the conveyor 12: when the chip level falls below the predetermined values, along the entire feeding line (belt conveyor and hopper), the control system 4 enables chip feed in the container 1 1 and the belt conveyor 12: if the level is not restored, it will trigger an alarm and later shut down the plant. The uptime of the pyro- gasifier from the time of the alarm signal is about 1 hour, then the control system shuts down the plant.

- the drying chamber: when the chip level falls below the predetermined values, the control system enables the chip feed in the container 1 1 , belt conveyor 12 and the hopper; if the level is not restored, it triggers an alarm and later shuts down the plant. The uptime of the pyro- gasifier from the time of the alarm signal is about 20 minutes, then the control system shuts down the plant.

Furthermore, due to the provision of the humidity and temperature probes in the drying chamber, the control system manages the chip filling amount and frequency to minimize the drying time.

- the dissociator and the pyrolysis process; the control system ensure optimal management of pyrolysis, by detecting the temperature parameters in the reactor, by detecting the flow-rate, temperature and pressure parameters of the output syngas and by controlling the combustion air flow. Failure to reach the required operating temperatures, pressures and flow rates will cause the control to trigger an alarm and later shut down the plant. The uptime of the pyro-gasifier

from the time of the alarm signal ranges from a few minutes to 30 minutes according to the detected fault.

- gas cleaning; the control system ensure optimal management of the purification process, detects ambient temperature and pressure parameters of the output gas and controls the active filter system. Failure to reach the required operating temperatures, pressures and flow rates will cause the control to trigger an alarm and later shut down the plant. The uptime of the pyro-gasifier from the time of the alarm signal ranges from a few minutes to 30 minutes according to the detected fault.

- the gas ramp; the control system manages the ramp by detecting temperature and pressure parameters of the output gas and the flare gas; if flare gas is present, a pressure switch actuates a step-up transformer (electric spark) that ignites the gas. The temperature probe K, operated by the control system ensures that the gas is actually ignited: if it is not, after a few ignition attempts, the control system finally shuts down the plant. The pyro-gasifier operates about 20 minutes from the time of the alarm signal, then the control system shuts down the plant. Conversely, when the flare is ignited (probe K) the control system, after 30 minutes, reduces the biomass and combustion air flows and runs the pyro-gasifier in idle mode. - the evacuation of ashes and sewage; at predetermined intervals, as automatically set by the control system and according to chip consumption (chip grade and moisture), the motorized unit are actuated.

- cogeneration: the control system manages the thermal power that is fed into the network by means of the diverter valves, the temperature probes and the calorie meter; if no thermal power is withdrawn (due to failures, outage or absence of a user) the control system actuates the self- contained cooling system (the free cooler of the pyro-gasifier and the radiator of the power generating set); in case of failure of the cooling system, the control system triggers an alarm and later shuts down the plant. The uptime of the pyro-gasifier from the time of the alarm signal is only a few minutes.

- electric power and cogenerator; the control system is fully interfaced with the switchboard of the cogenerator; the parameters of the power generating set and the powers delivered are centralized and managed by the control system which automatically optimizes the process; the alarm signals of the cogenerator become alarm signals of the control system. Upon alarm signal output, the gas is diverted to the flare and the power generating set is shut down.

- emergency: the control system has no control on the emergency buttons on the pyro-gasifier and on the switchboard of the control system. The actuation of the emergency button immediately shuts down the plant: it stops gas supply to the power generating set and turns it off, turns off the combustion air and syngas extraction pumps, opens the chimney, while the cooling pumps remain on and are only turned off at the preset temperature value (ISPEL thermostat).

In a possible embodiment, the control system is equipped with an uninterruptible power supply consisting of a sealed lead battery pack and an inverter, for a total three-phase power of 10 KVA 380V.

Due to the presence of the uninterruptible power supply, the continuous runtime of the electrical system is 3 hours, allowing total safe shut-down of the plant, in case of malfunction of power failure. The uninterruptible power supply is finally equipped with a backstop circuit and an emergency release.

The electric system of the control system includes 24V, 230V and 400V units.

Instantaneous electric power absorption is 15 kWe during operation of the plant; the control system manages and synchronizes the various units and actuators such that this power is never exceeded (intermittent alternating operation).

Once the gas has been purified by the above described systems, it is transferred via the ramp to the cogenerator.

It shall be noted that any known cogenerator model may be used, without limiting or altering the features of the remaining components of the plant, as described hereinbefore.

In a possible embodiment, the cogeneration part includes a stabilized-pressure gas control system which provides the output gas to a gas engine, i.e. ESC13MF(NG), for combustion.

The cogenerator may be one of the prior art cogenerators but the characteristics of the cogenerator will be preferably as follows:

- Prime power PRP: 249 KVA equal to 199.2 KW

- Power Factor: cos f 0.8

- Voltage: three phase 400V with accessible neutral (230 V phase/neutral)

- Frequency: 50 Flz.

- RPM: 1500 revolutions/T.

- Syngas engine (for instance, ESC13MF (NG), turbocharger intake, 6 in-line cylinders, water cooling, electric starter 24 Vcc.

- Alternator (for instance, MARELLI MJB 315 SB4), self-excited and self-regulating, nominal power 249 kVA, insulation / overtemperature class H/B brushless, with electronic voltage regulator, mechanical protection IP23, single-support construction, with parallel device.

- Control and monitoring switchboard, PSC-1 type, with user- programmable microprocessor management logic having a user-friendly interface, interfaced with the control system. - Circuit Breaker (for instance, ABB SACE), 4x400, to protect the generator, fixed-mounted with manual control.

- Stator ground protection relay 64S.

- Temperature probes PT 100 mounted on the windings (1 x phase) and on a bearing of the alternator for monitoring temperatures + control panel instrument for temperature display

- Soundproof frame made of galvanized sheet for outdoor use, ns. type D Silent version (noise level 70 ± 3 dB(A) at a free-field distance of 7 m and with no background noise).

- Radiator with blowing fan driven actuated by the diesel engine, with connection pipes, thermostatic valve and circulation pump, all mounted to the base of the assembly;

- Water preheating system;

- Starter lead batteries 24V;

- Exhaust gas silencer of residential type;

- Exhaust gas expansion joint, made of stainless steel, for connection of the engine exhaust gas outlet;

The power generating set is designed to be automatically operated by the

control system and is equipped with:

- An alarm/stop sensor for low oil pressure;

- An alarm/stop sensor for high water temperature;

- An alarm/stop sensor for low radiator water level;

- An oil level control sensor and refilling system with on-board 50- Liter tank.

It shall be finally noted that the power generating set is equipped with a heat exchanger to recover heat from the radiator (cylinder cooling) and exhaust gas heat. This thermal energy is available for the thermal cycle of the heating or air conditioning system (heat pump).

While the invention is susceptible of various modifications and alternative constructions, certain preferred embodiments have been shown in the drawings and described in detail. Nevertheless, it shall be understood that the invention is not intended to be limited to the particular embodiment as shown, but is conversely intended to cover all modifications, alternative constructions, and equivalents that fall within the scope of the invention as defined in the claims.

The use of "for example", "etc.", "or" indicates non-limiting, non- exclusive alternatives unless otherwise stated.

The use of "includes" means "includes but is not limited to" unless otherwise stated.

Claims

1 . A pyro-gasification plant comprising the following components: at least one system for storing and feeding chip material (1 ), at least one pyro-gasifier (2),

at least one system for recovering the gas flowing out of said pyro- gasifier,

at least one power cogeneration unit (3),

characterized in that

a control system (4) is provided, which control system (4) is in communication with one or more of said components, such that said control system (4) manages the operation of said one or more components,

a network of sensors is further positioned in the one or more components and in communication with said control system.

2. A plant as claimed in claim 1 , wherein said at least one pyro- gasifier (2) comprises at least one drying chamber (21 ) and at least one reaction chamber (22), the drying chamber (21 ) being in communication with said reaction chamber (22) via mechanical means for distributing the chip material, the activation/deactivation of these mechanical means allowing transfer from the drying chamber (21 ) to the reaction chamber (22), a system for detecting the moisture of the input chip material being provided at the inlet of said drying chamber (21 ) and being in communication with said control system (4), for activation/deactivation of said mechanical distribution means.

3. A plant as claimed in one or more of the preceding claims, wherein said pyro-gasifier comprises a pump unit for introducing combustion air, which unit pumps combustion air through an inlet into the reaction chamber (22), and a suction pump unit for extracting the output gas through an outlet of the reaction chamber (22), a delivery valve being provided for measuring and controlling the flow of input air and a suction valve being provided for measuring and controlling the flow of extracted gas, said valves being connected to said control system (4).

4. A plant as claimed in claim 3, wherein said introducing pump unit and said suction pump unit are connected via a mechanical direct drive shaft.

5. A plant as claimed in one or more of the preceding claims, wherein said pyro-gasifier comprises a the cleaning circuit located downstream from said outlet of the reaction chamber (22), which circuit comprises means for reducing the temperature of the gas and the first pumping means intended to remove the condensate resulting from temperature reduction.

6. A plant as claimed in one or more of the preceding claims, wherein said cleaning circuit comprises second pumping means and at least one heat exchanger for recovering the thermal energy resulting from temperature reduction.

7. A plant as claimed in one or more of the preceding claims, wherein said system for feeding and storing chip material comprises at least one container (1 1 ), in which container the chip material is placed, which container (1 1 ) comprises a movable chip-displacing floor, a system being provided for monitoring the storage of chip material, which is in communication with said control system (4), for activation/deactivation of said movable floor.

8. A plant as claimed in one or more of the preceding claims, wherein said storing and feeding system comprises means for transferring said chip material to said pyro-gasifier, said transfer means comprising a system for monitoring the feed of said chip material, in communication with said control system, for activation/deactivation of said transfer means.

9. A plant as claimed in one or more of the preceding claims, wherein said transfer means comprise a system for detecting the passage of chip material, in communication with said control system, for activation/deactivation of said movable floor.

10. A plant as claimed in one or more of the preceding claims, wherein said drying chamber (21 ) and/or said reaction chamber (22) have a system for monitoring the level of chip material, in communication with said control system (4), for activation/deactivation of said movable floor and/or said transfer means (12).

11. A biomass pyro-gasifier comprising an outer body that delimits an inner chamber,

the inner chamber having at least one drying chamber, designed to receive the biomass and at least one reaction chamber,

said reaction chamber having means for igniting a flame for biomass combustion,

characterized in that

Said drying chamber and/or said reaction chamber are at least partially surrounded by a thermal flywheel.

12. A pyro-gasifier as claimed in claim 11 , wherein a downstream catalyst system composed of ceramic elements is provided downstream from said reaction chamber, the gas produced by combustion being circulated in said system, said ceramic elements being headed by said reaction chamber.

13. A pyro-gasifier as claimed in claim 11 or claim 12, having one or more of the features of claims 2 to 6.