The present invention refers to a system and a process for the pyrolysation and gasification of organic substances.

In general, the present invention refers to technologies for producing fuel gases, which contain carbon monoxide, gasification processes, ash removing devices, and processes with decomposition of distillation products by inserting them into the gasification area.

The prior art is given by patent EP2411488B1 dealing with a system for pyrolysing and gasifying organic substances, in particular biomasses, comprising in cascade an evaporation module, a pyrolysis module and a gasifier. The organic substance is dried in the evaporation module and then transferred in the pyrolysis module for producing at least one syngas pyrolysis fuel gas and residual organic products. The residual organic products are then transferred to the gasifier for producing a gasification syngas fuel gas. The system allows channeling syngas pyrolysis fuel gas and gasification gas, from the pyrolysis module to an energy user. Burnt exhaust gases produced by such energy user are sent to the evaporation module, while the gasification syngas fuel gas passes from the gasifier to the pyrolysis module.

The gasification principle of EP2411488B1 allows efficiently producing clean syngas and allows lowering the necessary cleaning level. The gas recirculation inside the system for pyrolysing and gasifying organic substances allows using the high temperature of the syngas generated in the lower area, namely in the gasifier, to transform the biomass into charcoal, in the pyrolysis module. The gasified charcoal in the lower area, namely in the gasifier, allows strongly increasing the temperature and operating as filter for the syngas, with the result of allowing to trap the majority of impurities and to perform a first cleaning of syngas inside the pyrolysis module. Moreover, impurities which remain trapped in the charcoal matrix are gasified in the gasification area, thereby contributing to generate a fine fuel syngas. The syngas globally extracted from the system for pyrolysing and gasifying organic substances is composed of a mixture of gasification gas coming from the gasifier placed in the lower area and of pyrolysis gas generated when transforming the biomass into charcoal in the pyrolysis module.

The process for extracting syngas of EP2411488B1 is based on the compliance with two major operating conditions: 1) transforming biomass into charcoal needs a certain interval of time, depending on the temperatures present in the pyrolysis area. These temperature are function of: electric resistances, as support to allow providing energy to the biomass; a flow of hot gas coming from the gasification area, main source of necessary heat to perform the pyrolysis and then generate charcoal; 2) charcoal must keep the impurities present in the syngas. Greater amounts of syngas correspond to greater amounts of impurities and of thermal energy transported to perform the pyrolysis. Due to this, the flow of syngas must have a certain value. Moreover, the type of charcoal depends on the type of biomass being used. Charcoal can have a more or less porous structure and therefore a more or less pronounced filtering and catalyzing power on impurities.

During the process for extracting syngas, it can happen that the saturation of impurities occurs early, and that therefore the filtering effect of charcoal does not occur. This phenomenon occurs especially when the amount of generates syngas is increased to increase the capacity of the system.

A way to solve this problem is suitably dimensioning the pyrolysis area, so that the available volume allows forming enough charcoal to trap impurities deriving from a higher amount of syngas .

However, making of reactors, which are as a whole bigger and bigger, implies costly assembling and on-site construction operations, instead of building gasifiers in a single pre-assembled piece and which can be transported without particular requirements, in addition to unavoidable limitation to the heat exchange, in the pyrolysis area. The increase of sizes of the pyrolysis area can strongly reduce the transformation of biomass into charcoal and, consequently, the filtering effect and the gasification of charcoal in the lower area. In particular, the build-up of temperatures developed and necessary to the process for extracting syngas can disappear. In fact, it must be remembered that the biomass is not a good heat conductor. Therefore, bigger and bigger volumes make it more and more difficult to obtain a heating which is as much as possible adequate and homogeneous .

Object of the present invention is solving the above prior art problems, by providing a system and a process for the pyrolysation and gasification of organic substances, wherein the influence of sizes of volumes involved in forming syngas does not affect the efficiency of the process for producing syngas .

A further object is providing a system and a process for producing syngas through a pneumatic thrust which allows essentially reducing the use of forced blowers.

The above and other objects and advantages of the invention, as will appear from the following description, are obtained with a system for pyrolysing and gasifying organic substances as claimed in claim 1.

Moreover, the above and other objects and advantages of the invention are obtained with a process for pyrolysing and gasifying organic substances as claimed in claim 7.

Preferred embodiments and non-trivial variations of the present invention are the subject matter of the dependent claims.

It is intended that all enclosed claims are an integral part of the present description.

It will be immediately obvious that numerous variations and modifications (for example related to shape, sizes, arrangements and parts with equivalent functionality) can be made to what is described, without departing from the scope of the invention as appears from the enclosed claims.

The present invention will be better described by some preferred embodiments thereof, provided as a non-limiting example, with reference to the enclosed drawings, in which:

- Figure 1 shows a functional schematic view of a preferred embodiment of the system for pyrolysing and gasifying organic substances according to the present invention; and

- Figure 2 shows an enlarged portion II of the previous Figure.

With reference to Figure 1, it is possible to note that a system for pyrolysing and gasifying organic substances according to the present invention comprises at least one evaporation module 10 for drying biomass B, at least one pyrolysis module 20 for producing syngas pyrolysis fuel gas Sp and organic residue substances R, at least one gasifier 30 for producing gasification syngas fuel gas Sg.

Advantageously, the system according to the present invention further comprises at least first and second channeling means, shown in the Figures respectively with reference numbers 100 and 200, such first channeling means 100 being adapted to address at least one first flow of fuel gas VI from such at least one pyrolysis module 20 towards at least one gasifier 30 and such second channeling means 200 being adapted to address at least one second flow of fuel gas V2 from such at least one pyrolysis module 20 towards at least one external energy user U.

In particular, with reference to Figure 2, it is possible to note that the system for pyrolysing and gasifying organic substances comprises at least one central tube 300 adapted to facilitate a vertical ascending gas flow by pressure drop and fixed deviating means 104 of a gas flow, towards the first and second channeling means 100, 200. The first channeling means 100 comprise regulating means 101 of the first flow VI of fuel gas, to allow circulating fuel gas through the pyrolysis module 20 and the gasifier 30.

Preferably, the regulating means 101 are composed of at least one forced blower adapted to drive the flow from an annular chamber 102 towards at least one collecting ring 103.

Moreover, the regulating means 101 are adapted to circulate fuel gas with a constant volume.

The present invention further deals with a process for the pyrolysation and gasification of organic substances implemented through a system as previously described. In particular, the process according to the present invention comprises the steps of:

a) inserting biomass B into at least one evaporation module 10;

b) drying the biomass B and passing the biomass B in at least one pyrolysis module 20;

c) passing gasification syngas fuel gas Sg from at least one gasifier 30 to the pyrolysis module 20, to allow a pyrolysis reaction of biomass B inside the pyrolysis 20 and generate syngas pyrolysis fuel gas Sp; d) forming a mixture of syngas pyrolysis fuel gas

Sp and gasification syngas fuel gas Sg;

e) driving the first flow of fuel gas VI from such at least one pyrolysis module 20 towards such at least one gasifier 30 through the first channeling means 100;

f) driving the second flow of fuel gas V2 from such at least one pyrolysis module 20 towards at least one external energy user U through the second channeling means 200.

The system and the process for the pyrolysation and gasification of organic substances according to the present invention therefore allow obtaining their preset objects.

In order to be able to keep the benefits of a system of gasification of biomass, also with greater amounts of generated syngas, without incurring in problematic over-dimensioning, a flow of the syngas fuel gas generated in the lower gasification area has been uncoupled and a recirculation has been created.

A flow of syngas fuel gas is continuously circulated through a forced blower, through the pyrolysis area and towards the gasification area.

A remaining flow restante of syngas fuel gas is continuously sent towards at least one external user .

These two flows are independent, though their source is the same. In fact, the flow re-circulated at a constant volume is set depending on the transformation of biomass into charcoal.

The amount of syngas fuel gas sent to external users goes on depending on blowing parameters of the oxidizing agent in the gasification area, and namely air, water, steam.

The extracted syngas fuel gas is a mixture of gasification gas and pyrolysis gas, wherein the pyrolysis gas generated when transforming biomass into charcoal is re-circulated. In this way, the part of syngas fuel gas which has been recirculated allows transforming the biomass into charcoal and therefore generating syngas pyrolysis fuel gas.

Possible impurities dragged by the flow of syngas fuel gas are not a problem and remain inside the reactor following the gasification in the lower area of the system, keeping a good energy efficiency for the transformation.

The re-circulated syngas fuel gas is loaded with impurities, which are removed due to the effect of a molecular dissociation of polluting substances in the gasification area at high temperature .

Instead, the syngas fuel gas extracted to be used by external users does not cross the pyrolysis area. In this way, the syngas fuel gas can keep its features of a high cleaning due to the high temperatures in which it has been generated.

These considerations are supported by the analyses on impurities found in the gas.

However, the syngas fuel gas extracted to be used by external users is a mixture of gasification gases and of pyrolysis gases, wherein the pyrolysis gas is re-circulated before being mixed with the syngas fuel gas generated in the gasification area.

The system of the invention comprises an empty central tube. Moreover, the separation of the two areas occurs through a simple pressure drop due to the volume of material, without needing furthe4r separating mechanical devices, such as cochlea. The gas generated in the lower part rises through the empty central tube, encountering less resistance, with respect to the configuration without central tube wherein the volume is wholly occupied by charcoal and biomass. The re-circulated volume of gas is extracted by the side from an annular separating chamber, after having passed through the biomass per to allow converting biomass into charcoal.

It is possible to adopt a configuration with two outlets for gas to be re-circulate. Alternatively, it is possible to adopt multiple outlets fitted in a single collecting ring.