WO2008122875A2

WO2008122875A2 - Plant and method for the production of electric power

Info

Publication number: WO2008122875A2
Application number: PCT/IB2008/000852
Authority: WO
Inventors: Mauro Grillenzoni
Original assignee: Delca Spa; Ecoengineering Impianti Srl
Priority date: 2007-04-10
Filing date: 2008-04-09
Publication date: 2008-10-16
Also published as: ITPI20070039A1; EP2156097A2; WO2008122875A3

Abstract

The present invention concerns a method for the production of electric power. In an initial phase it is prearranged a so-called R.D.F. and its following gasification through a distillation and combined gasification operation. In this manner it is obtained, in the lower part of the gasifier a first gas that is free from distillates, so-called light gas and substantially free from distillation's products as tar and/or similar. From the upper part of the gasifier, on the other hand, it is obtained a second gas, the so-called front-end gas, constituted essentially from the distillation and gasification products produced in the lower part. The light gas produced can feed an engine or turbine and similar, generating this way mechanical energy. Afterwards it is possible the production of electric power by means of connection to at least an alternator. The present method is then realized through an appropriate plant comprising a two-stage gasifier (1) and connected to an endothermic engine (91) and to an alternator (92) for the production of power.

Description

TITLE

"PLANT AND METHOD FOR THE PRODUCTION OF ELECTRIC

POWER"

Technical Field

The present invention refers to a plant and a method for the production of electric power; and in particular it refers to a plant and a method for the production of electric power through an otto cycle and/or a diesel cycle fed by a syngas produced by the gasification of the so called R.D.F..

State of the Art

Plants and methods of this kind are well known and used; despite that, the same present some inconvenient.

Normally, in some plant typologies according to the Art, the production of electric power is obtained through an otto cycle, or diesel cycle and this endothermic engine is fed by Diesel fuel, fuel oil, gas or similar. Particularly, through the last years, the need of reusing in some way the waste, and in particular, the need to use the municipal solid waste called "R.S.U.", has grown. In this way there is a double advantage as they are disposed and, in the same time, energy is produced, maintaining low the possible environment pollution. For this aim, the "R.D.F." (acronym that refers to - Refuse Derived Fuel), is a triturated fuel obtained by the treatment of the dry fraction of municipal solid wastes and/or other special assimilated wastes.

When the recyclable materials as glass, metals, inert and the not combustible part are eliminated, the remaining portion of the wastes is separated through a mechanical selection in two fractions: dry and wet. At the end of the selection process, the dry residual of the waste is triturated and transformed into fuel for the heat-recovery and the cogeneration of electric and/or thermal power, in appropriate incinerator plants supplied with regeneration systems for the power produced by the combustion.

The R.D.F. is classifiable into different qualitative grades, based on the technical rules Uni 9903-1 and further changes and integrations. The combustible R.D.F., of normal quality, is simply called C.D.R.; it is regenerated from municipal wastes and from special safe wastes.

It is also subjected to different treatments finalized to various aims. For example to guaranty a sufficient calorific power, reduce and control the sanitary and environmental risk, reduce the presence of metallic, glass, inert, putrescible materials, and the presence of humidity, remove the dangerous substances for the purposes of combustion, as some types of polymers and potentially exploding materials.

The combustible of high quality, classified as "R.D.F.-Q" based on the technical rules Uni 9903-1, allows to obtain the green certificates and can be advantageously used for the production of electric power.

The R.D.F, in the plants according to the prior art, is used to feed a gasifier. With gasifier it is intended a plant that, from various materials, between which specific types of waste, derives gaseous fuel that uses for the production of energy. Such plants are proposed as an alternative to the incinerators. The gasifiers utilize the molecular dissociation, called pyrolysis.. In a closed environment, with a temperature around 500° and in presence of under- stoichiometric air, the organic waste, or rather the ones that contain carbon, can be completely destroyed by resolving the molecules into simpler molecules of carbon monoxide, hydrogen, methane, that creates the so called syngas. The syngas can be then burnt in a boiler to utilize the heat producing overheated steam that will feed an electric turbine, or it can be used as a combustible for endothermic motors, or hydrogen could be obtained from it to be then used in piles as combustible, to obtain the production of electric power.

However, the syngas contains a high level of tar, or anyway distillates, which have brought until now all the plants, according to the prior art, to not present a sufficient cost-benefit ratio for their diffusion. Indeed, the tar, which is found in the syngas exiting from the gasifier, in order to be sent, in particular, to an endothermic engine, must be pre-emptively treated, to reduce the dust, but most importantly it must be purified, to eliminate the tar contents. The presence of tar in the syngas, indeed, if not eliminated, would entail into a severe problem of atmospheric pollution exiting from the same endothermic engine.

The treatment phase and the elimination of tar from the syngas, according to the prior art, implies an increase of the plant's costs and consequently of the cost of the produced energy. Hence, the plants for the production of electric energy, and in particular for the production of electric energy through an endothermic engine fed by syngas derived from the gasification of the so called R.D.F., are not often used or considered as usable.

Disclosure of invention

The aim of the present invention is to have a plant and a method for the production of electric power, through an endothermic engine and/or a gas turbine or similar fed by a syngas produced by the gasification of the so called R.D.F., which is able to remedy the inconvenient of the plants according to the prior art.

In particular the aim of the present invention comprises a plant and a method for the production of not expensive electric energy through the gasification of the R.D.F. , despite the cost for the tar elimination procedure.

These and other aims are obtained with the present invention relative to a plant for the production of electric energy, through an endothermic engine and/or a turbine and/or similar.

The plant for the production of electric energy, through an endothermic engine and/or a turbine and/or similar according to the present invention and where said endothermic engine and/or turbine and/or similar are fed by a gas that is produced from the gasification of the so called R.D.F., comprises a gasifier, where said gasifier is a so called two-stage gasifier, or rather a gasifier able to produce a first gas, called front-end gas, and a second gas, so-called light gas, called light gas being substantially free from tar, and said endothermic engine and/or turbine and/or similar, being fed directly by means of said light gas.

In substance the plant, according to the present invention, comprises the presence of a so-called two-stage gassifier . The two-stage gasifϊer differentiates, essentially, from the one-stage, by the fact that it comprises in the upper part of the same gasifϊer a so-called still and that only a part of the gas exits from the head of the gasifϊer.

In the single-stage gasifϊer the whole gas, the syngas, is produced by gasification of the R.D.F. and exits from, the gasifϊer as a sole gas, containing substantive quantity of tar.

In the two-stage gasifier, on the other hand, the gasification of the R.D.F. and the distillation of the tar happen in two different zones of the gasifier, in a controlled way, maintaining an optimal temperature when the front-end gas exits. Such temperature, preferably around 150 °C, is controlled by passing a more or less high quantity of gas, coming from the gasification zone, through the upper layer of combustible, that is found in the distillation zone.

In this way, the lower section of the gasifier is in a condition of gasing some combustible that has already ceded the distillates and, in particular, it is free from tar, that creates the above mentioned technical problems and high costs, during the purification process, to be able to feed the endothermic engines.

It is necessary to understand how the fact of applying a two-stage gasification method, or rather a two-stage gasifier that feeds directly the exiting light gas to an endothermic engine, eventually through a simple dust exhaustion of the same light gas, is object of an inventive step able to exceed the existent pre-concepts of the state of art. The field relative to the production of electric power by means of R.D.F. that, in the last years, has represented a starting point for many studies and researches and has, anyway, given negative results as the syngas when produced by the one-stage gasification, according to the prior art, has shown the need of processing, for example expensive and not reliable treatment, further to its production in the one-stage gasifier, which processing, needed to eliminate the tar in the syngas, have made the process as failing. The R.D.F. , currently produced, was indeed destined mainly to be burnt in the usual incinerators, in a way to eliminate the same waste, even at the expenses of the energy production from the waste that, in many cases, was considered as non-economical or extremely expensive in the installation. Consequently the idea to use the R.D.F. to produce energy, in particular electrical energy, was then considered as subordinate respect to the elimination of the same waste and the setting of all the researches and experiments were made with the presence of a common incinerator or to a traditional single-stage gasifier, with the above mentioned problems. The idea, original and advantaged and relative to the use of a two-stage gasifier in a method and a plant for the production of electrical power starting from the R.D.F., has brought the need of important studies and experiments, with the aim of identifying the problem and to plan a method and a device able to resolve the above mentioned inconvenient. For example, the study of the problem and the experimentation done have brought to notice a greater reduction of the Nox respect to the one obtained when using methane as the reburning fuel. In particular, it has been noticed that the reduction obtained is between the 65% and the 75% (respect to the concentration of NOx in absence of reburning), while the reduction obtained with the methane gas used as the reburning fuel is between the 33% and the 65%.

Advantageously the two-stage gasifier eliminates the distillates and in particular the tar and gasifies the fuel in a way to obtain the so-called light gas, substantially free from pollutant products such as tar, or similar.

Advantageously the heating of the so-called still happens in a direct and indirect way: direct, through the gas that goes through the R.D.F.; and indirect, through the remaining part of the gas that licks the walls of the still.

The products of the two-stage gasification process are therefore advantageously the two gas: front-end gas, made from the products of the gasification and distillation of the RDF and from the gas coming from the zone below the gasification; the light gas, coming from the gasification zone and free from the distillation products, tar and oil and able, after the cooling and a simple filtering or elimination of the dust, to be sent into endothermic engines.

Moreover, advantageously in the plant according to the present invention, the partial oxidation of the solid fuel, such as to transform it into gaseous fuel, happens through the combustion of a fraction of the fed material, or rather, the thermal energy necessary for the drying and volatilization of the remaining part is supplied, through the combustion of a fraction of the same fed material.

The process is made in an atmosphere that is weak of oxygen (under stoichiometric ), or better with oxygen in defect respect to the quantity needed for a complete combustion.

According to a preferred and advantaged solution of the plant, according to the present invention, the produced gas will then follow two separated routes, according to the physic/chemical features; a different route for the front-end gas and another one for the lightgas. The front-end gas is substantially a synthetic gas, created in the lower zone of the gasifier (gasification zone) and that, by crossing the overhanging RDF, warms it up, enriching with the distillation's products. Its heat value is about 1.340 Kcal/Nmc and its temperature is about 160 ÷ 200 °C.

This gas is not suitable for the direct application into engines with internal combustion, as the tar containment would create huge problems regarding the continuity to the same engine.

This gas is advantageously used in the following manner: it is burnt in a combustion chamber, with permanent temperatures > than 850 °C for at least 2 seconds, with the 6% of 02 free, so that it gets completely free from the oily and tarry residuals (that get burnt completely) with great results. Afterwards, the gas is sent into a post-combustion chamber and the hot smokes are used to generate hot water or air or vapour which is then used locally or, anyway, for thermal use.

In the case is necessary to use also the front-end gas, in uses where it is requested the highest cleanliness of the gas, it is possible to proceed with the detarration of the gas, using a system that brings the front-end gas to a high temperature (about 900 ⁰C, for about 2 seconds); said system substantially is made by a particular refractory chamber, where it is used a methane burner (or LPG) used as a oxygen comburant. The quantity of the sent oxygen represents the stoichiometric air for the auxiliary combustible (methane or LPG)₅ but not sufficient to burn the synthetic gas contained in the same chamber.

The front-end gas, de-tarred and dusted, can at this point be mixed to the light gas.

The light gas is, essentially, a gas that is completely free from oily or tarry residuals (released in the upper part of the gasifier) and contains only dust residuals, which are easily deletable.

In a preferred executive solution of the present plant, the light gas exits at a temperature of about 650 °C and presents a n.c.v. of about 1.290 kcal/Nmc.

The light gas is then cooled, for example, with a gas/water exchanger and the hot water recovered and dusted with a bag filter, which it can be advantageously used in an endothermic engine, in particular, in an engine that is suitable for the gas with a low n.c.v., coupled to a generator to produce electric energy.

The invention has as a solution also a method for the production of electric power, comprising at least the operations of: a- prearrangement of a so called R.D.F.; b- gasification of said R.D.F., through a distillation and a combined gasification, obtaining, in the lower part of the gasifier a first gas free of distillates, the so called light gas, substantially free from distillation products, and/or tar and/or oil; and from the upper part of the gasifier a second gas, the so called front-end gas, substantially made from the products of said distillation and the gas of the gasification produced in the lower part. c- Feeding of said light gas in an endothermic engine and/or turbine and/or co-generator and/or similar, said endothermic engine and/or turbine and/or co-generator being devices that are able to transform the natural chemical energy of the light gas into a mechanical energy and afterwards to transform said mechanical energy into electric energy, being said devices joint to at least an alternator or similar for the production of electric energy. Alternatively to the production of a gas suitable to be used directly in the endothermic engines for the production of electric and thermal energy, the method and the plant, according to the present invention, can comprise the use of the gas for the recovery of hydrogen at the molecular state and of other products of industrial interest.

The method and the plant, according to the present invention, beyond to guarantee a safe functioning, both in the management and environmental impact, are easy and useful to use also in the traditional industries (cement factory, distilleries, brickyards, ceramic and other industrial activities that need a lot of electric and thermal energy), for the economy of the investment, the limited encumbrance, the quality of the emissions; the features of the SSF (solid similar fuels) or usable R.D.F., that allow an easy stocking and automatism of the process.

The method and the plant, according to the present invention, if found in the traditional industries, advantageously would lower the need to realize new plants for the recovery of the above mentioned types of wastes and, therefore, of new emissions of CO2, as the gas and/or the hydrogen produced will substitute, in said plants, the production of electric and/or thermal energy and the fuels from non renewable sources, as methane, coal, oil fuel, etc.. with no significant variations and, in some cases, with improvements in the produced emissions, both in the qualitative and quantitative terms.

A further advantageous executive solution comprises a two-stage or bi- stage gasifier of low temperature type and implies that the method and the plant, using this method, do not comprise emissions into the atmosphere of pollutant or harmful substances, in the total absence of chimneys. The whole happens in a close and controlled environment, where the only effluent is demineralised, reusable water.

Substantially, the advantages deriving from the usage of a method and a plant according to the present invention, are, in terms of electric and thermal energy production, through gas turbine plant that operates with hydrogen with efficiency equal to 40%: production of electric and thermal energy using fuel cells and efficiency between the 60 and 70% and thermal recovery obtained by the steam; production of hydrogen to be used for the public and private car traction; production of stocked carbon dioxide liquid or solid or other sub-products of industrial interest easy to locate in the market; locate close to the possible users; increase of the hygiene-sanitary quality of the water surface and bed and of the air quality; possibility to contain the dimensions of the plants; - possibility to distribute in the territory, according to strategic plans, the collocation of said plants and consequent reduction of the environmental impact given by the nets of the long-distance lines.

Brief description of drawings

The present invention will be better understood by referring to the enclosed drawings where:

Fig. 1 shows a flowchart of the method, according to the present invention; Fig. 2 shows a feature of the stoker of the plant, according to the present invention;

Fig. 3 shows a feeling belt of the fuel of the plant, according to the present invention;

Fig. 4 shows a feature of the priming stator or skip of the fuel of the plant, according to the present invention;

Fig. 5 shows a feature of the priming stator or skip of the fuel and of the feeding belt to the gasifier of the plant, according to the present invention;

Fig. 6 shows a feature of the charging door of the fuel to the gasifier of the plant, according to the present invention; Fig. 7 shows a two-stage gasifier of the plant, according to the present invention;

Fig. 8 shows a feature of the zone generating thermal energy from the front-end gas of the plant, according to the present invention; Fig. 9 shows a feature of the cooling and dusting zone of the light gas of the plant, according to the present invention;

Fig. 10 shows a feature of the zone generating electric energy of the plant, according to the present invention; Fig. 11 shows an assembly view of the plant, according to the present invention.

Description of a preferred pattern realization

With reference to Fig. 1, are shown the steps, or equally the operations, relative to the method for the production of electric power, according to the present invention.

In particular, it is initially arranged a so-called R.D.F. or rather a R.D.F.- Q, which is treated through a combined distillation process and a gasification operation, or rather it is gasified in a bi-stage process that produces a first gas, the so-called light gas, substantially free from distillates and/or tar and/or oil products and a second gas, the so-called front-end gas, made essentially from the products of the gasification and distillation.

Thus, the two gases follow two different routes: the light gas, since it is advantageously free from pollutant products as tar or oily or similar residuals, can be used, for example, to feed directly an endothermic engine, for example an otto or Diesel cycle engine, as fuel, providing, therefore, to feed the engine, where such engine, for example, is joint to a generator or alternator for the production of electric power.

Alternatively, the light gas could feed directly a turbine or other similar devices able to transform the natural thermal energy of the light gas into mechanical energy and afterwards into electric energy.

The steps, cut out with a section line in the route of the flowchart of the light gas in fig. 1, are steps that are not strictly necessary, as the light gas could directly feed an endothermic or similar engine. Advantageously, nevertheless, are found in the method, relevantly to the steps of the method for the light gas, also the step of cooling said light gas, for example in a water-gas exchanger, and to dust, or rather eliminate the dust of the light gas, for example with a filter, in particular with a bag filter or similar. The light gas can be then advantageously stocked in appropriate tanks and the used in a second time.

On the other hand for what concerns the method's steps according to the present invention, for the front-end gas, the same is cleaned from the oily or tarry or similar residuals. The cleaning happens preferably with a combustion, or rather, the front-end gas is burnt in a combustion chamber, at for example a temperature > than 850°C for at least 2 seconds and with a level of free O₂ >6% , where in this chamber the front-end gas gets free from the oily and tarry residuals that burn.

It is possible to use the hot smokes produced by the combustion to generate hot water or vapour to employ locally, to be used in a Rankine or ORC cycle and produce further electric energy or, anyway, for thermal usage.

It is also possible advantageously to de-tar the front-end gas, by using a system that brings the front-end gas to a high temperature, about 900°C, for at least 2 seconds; the system comprises essentially a particular refractory chamber, where it is used a methane burner (or GPL) used as an industrial oxygen comburant. The quantity of the sent oxygen represents the stoichiometric air for the auxiliary combustible (methane or GPL), but not sufficient to burn the synthetic gas contained in the same chamber. The de-tarred fron-end gas can also be advantageously dusted and/or can be mixed to the light gas, as shown in fig. 1, where the steps, cut out with a section line in the route of the flowchart of the light gas in fig. 1, are not strictly necessary.

The plant, according to the present invention able to realize the method according to the present invention and described above, is illustrated in an assembly view in fig. 11.

The plant for the production of electric energy, according to the present inventing, comprises a zone for the production of electrical energy 9, illustrated in detail in a preferred executive solution in fig. 10; said zone comprising preferably an endothermic engine 91 and an alternator 92.

La other preferred executive solutions, and without leaving the protective area and from the teaching of the present ivention, the zone for the production of the electrical energy 9 can comprise a turbine and/or similar or more generally devices that are able to transform the natural thermal energy of the gas into mechanical energy and afterwards into electrical energy.

The plant, according to the present invention, functions preferably using R.D.F., identified above, and substantially performs it major advantageous with a R.D.F.-Q.

The R.D.F., or anyway the fuel of the plant according to the present invention, feeds a gasifier, in particular a two-stage gasifier 1, illustrated also in fig. 7, by means of a feeding system that, in a preferred executive solution, is illustrated in fig. 11 and, in its parts, in fig. 2, 3, 4, 5, and 6.

It is illustrates, in particular in fig. 2, a stocking and feeding device 2, made advantageously by a simple plated container, opened in the upper part to allow the loading of the material, and comprising a belt 22 in the lower part, in order to convey the material toward the slanting belt 3, shown in particular in fig. 3, that feeds the skip 4.

The feeling skip, shown in particular in fig. 4 and 5, is a device based on a container 4, so-called skip, binded from at least one, preferably two guides 41, that drive the skip 4, according to a vertical route, preferably parallel to the gasifier 1. With reference t Fig. 5, when the skip 4 reaches the end of stroke, the same makes a rotation on the horizontal axis and release the material on the belt 5, belonging to the feeding group 6 of the gasifier 1.

The feeding group 6 of the gasifier 1 is shown in detail in a preferred executive solution in fig. 6. The above mentioned feeding group 6 comprises a belt 5 that conveys the material in a double feeding valve, preferably an oleodynamic controlled type. The double feeding valve comprises preferably a charging door 61, a chamber 62 sealed by two hatches 63, 64 that open alternatively and have a double function that are to avoid the downflow of the gas and the entering of the atmospheric air that could alter the stoichiometric equilibrium inside the gasifier 1.

With reference to Fig. 7, it is shown a two-stage gasifier 1, made mainly to use the fuels that have an elevated carbon content, as the RDF. The two-stage gasifier 1 comrpises, in the upper part, a still 11 and a body zone 21.

The gasification of the R.D.F. and the distillation of the tar happen in a controlled way, maintaining an optimal temperature when the front-end gas exits. Such temperature is preferably around 150 ⁰C, and is advantageously controlled by passing a more or less high quantity of gas, coming from the gasification zone, through the layer of combustible, that is found in the distillation zone. In this way, the lower section 31 of the gasifier is in a condition of gassing some combustible that has already ceded the distillates and, in particular, it is free from tar, that creates the above mentioned technical problems and high costs, during the purification process, to be able to feed the endothermic engines.

The heating of the still happens in a direct and indirect way: direct, through the gas that goes through the R.D.F.; and indirect, through the remaim^'ng part of the gas that licks the walls of the still 11. The products of the two-stage gasification process are the two gases that follow:

Front-end gas, constituted by the products of the pyrolysis and distillation of the RDF and by the gas coming from the lower gasification zone;

Light gas, coming from the gasification zone and free from the distillation's products, tar and oil and suitable, after its been cooled and cleaned, to be sent into endothermic engines.

In a preferred executive solution in the two-stage gasifier according to the present invention, the extraction of the ashes is automatic, in function to the level reached by the same within the gasifier. In the gasifier 1 the ashes are comprised between the rotating grid 41 and the combustion's zone. On the gasifier 1 are also advantageously installed some thermocouples of which one of them is installed under the grid 41 and another one on the upper part of the ashes' zone.

Fitted as an experiment an ideal level of ashes layer in the gasifier (so that it protects the grid and it is not to much high to occupy the combustion's zone) so that, if the layer of ashes is too low, the lower thermocouple (underneath the grid) will flag with a raised temperature ,while, if the layer of the ashes is too high, the upper thermocouple will flag with a decreased temperature. The rotation of the grid and, therefore, the extraction of the ashes, will happen in relation of such taken temperatures, in an automatic way and such to guarantee a correct and continuous functioning of the gasifier and of the relative process of the gasification. Moreover the volume ratio between the two gases is advantageuously adjustable, as a function of the draught and therefore of the adjustment of two valves placed on each of the two tubings (valve of the front-end gas and the valve of the light gas) which are not shown. Preferably the ratio is 4 (light gas): 1 (front-end gas). Exiting from the two-stage gasifier are found, therefore, both the light gas and the front-end gas and, in particular and advantageously, the two gases follow different routes, according to the method described and shown in fig. 1.

In particular, the light gas ( that is a gas free from the oily or tarry residuals that have been released in the upper part of the gasifier, from which it exits at a temperature of about 650°C and with a n.c.v. of about 1.290 Kcal/Nmc) can be sent directly in the zone where it is produced the electric power 9 and used as a combustibile.

According to an alternative executive solution shown, in the case where the light gas contains a dust residual, the same can be cooled in the cooling and dusting zone 8 shown in fig. 9, for example by means of a water/gas exchanger 81, that can comprise an advantaged recovery of the hot water, and afterwards it can be dusted, for example, with a bag filter 82.

In this way the gas can be perfectly used in an endothermic engine, for example in an endothermic engine 91 suitable for gas with a low n.c.v., which can be coupled to an alternator 92 to produce electric power.

With reference to Fig. 11 and to fig. 8, the front-end gas is a syngas ( created in the lower zone of the gasifier 1 or gasification zone) that, crossing the overhanging RDF, it warms it up, enriching itself with the distillation's products, exiting the gasifier preferably with a calorific value of about 1.340 Kcal/Nmc and with a temperature of about 160÷200 ⁰C. The front-end gas is not suitable for the direct application into engines with internal combustion or similar, as the tar containment would create huge problems regarding the continuity to the same engine.

It is therefore advantageously included in the plant, according to the present invention, to clean the front-end gas from the oily and tarry residuals, by burning the fornt-end gas in a combustion chamber 71, with a temperature > than

850°C for at least 2 seconds, in a way that the front-end gas gets free from the oily and tarry residuals that burn completely.

This gas is therefore sent into a post-combustion chamber 72, comprising moreover a free level of 02 > than 6% and the hot smokes produced are used to generate hot water or steam to use locally, or in a Rankine or ORC cycle, or to produce thermal power.

Moreover, (in the case is necessary to use also the front-end gas, in uses where it is requested the highest cleanliness of the gas) it is possible to proceed with the detarration of the front-end gas, using a system that brings the front-end gas to a high temperature about 900 ⁰C, for 2 seconds; said system substantially is made by a particular refractory chamber, where it is used a methane burner or GPL or similar used as a oxygen comburant.

The quantity of the sent oxygen represents the stoichiometric air for the auxiliary combustible methane or GPL, but not sufficient to burn the syngas contained in the same chamber. The front-end gas, when detarred, can also be dusted and thus advantageously mixed to the light gas.

Claims

1. Method for the production of electric power, comprising at least the operations of: d- prearrangement of a so called R.D.F.; e- gasification of said R.D.F., through a distillation and a combined gasification, obtaining, in the lower part of the gasifier a first gas free of distillates, the so called light gas, substantially free from distillation products, and/or tar and/or oil; and from the upper part of the gasifier a second gas, the so called front-end gas, substantially made from the products of said distillation and the gas of the gasification produced in the lower part. f- Feeding of said light gas in an endothermic engine and/or turbine and/or co-generator and/or similar, said endothermic engine and/or turbine and/or co- generator being devices that are able to transform the potential chemical energy of the light gas into a mechanical energy and afterwards to transform said mechanical energy into electric energy, being said devices joint to at least an alternator or similar for the production of electric energy.

2. Method according to claim 1 characterized by the fact that it comprises also the operation of cooling said light gas, for example in a water-gas exchanger or similar, in particular cooling said ligh gas in correspondence of the exit of said ligh gas from the process of gasification.

3. Method, according to claim 1 or 2, characterized by the fact that it comprises the operation of dusting, or rather of eliminatine, the dust of said ligh gas, for example with a filter, in particular a bag filter or similar, in particula dust said ligh gas when it exits from said cooling.

4. Method, according to one or more of the previous claims , characterized by the fact that it comprises also the operation of stocking said light gas.

5. Method, according to one or more of the previous claims , characterized by the fact that it comprises also the operation of cleaning said front-end gas from the oily and tarry or similar residuals, through a combustion process, or rather by burning said front-end gas in a combustion chamber.

6. Method, according to the previous claim , characterized by the fact that said combustion process is controlled by means of a permanence at temperatures that are essentially greater than 850°C for at least 2 seconds with a level of free O₂ substantially > than 6%.

7. Method, according to one or more of the previous claims , characterized by the fact that it comprises also the operation of using the hot smokes produced by said combustion of the front-end gas to generate thermal energy and/or hot water and/or steam.

8. Method, according to one or more of the previous claims , characterized by the fact that it comprises also the operation of detarring the front-end gas, through the permanence of said front-end gas at high temperatures, substantially between 850°C and 950°C, preferably 900°C, for at least 2 seconds, preferably in a refractory chamber.

9. Method, according to one or more of the previous claims , characterized by the fact that said refractory chamber comprises the usage of a burner that uses methane gas or LPG or similar as combustibile and, as comburant, oxygen and where the quantity of the sent oxygen represents the stoichiometric air for the methane or LPG or similar combustible , being not sufficient to burn said front- end gas.

10. Method, according to one or more of the previous claims , characterized by the fact that it comprises also the operation of dusting said front-end gas, when exiting from said operation of detarring, for example in a bag filter or similar.

11. Method, according to one or more of the previous claims , characterized by the fact that it comprises also the operation of mixing said front-end gas to said light gas, in particular, mixing said front-end gas to said light gas in correspondence to the exit of said light gas from said cooling operation.

12. The plant for the production of electric energy, through an endothermic engine and/or a turbine and/or similar; said endothermic engine and/or turbine and/or similar are fed by a gas that is produced from the gasification of the so called R.D.F., is characterized by the fact that said plant comprises a gasifier, where said gasifier is a so called two-stage gasifier (1), or rather a gasifier able to produce a first gas, called front-end gas, and a second gas, so-called light gas, called light gas being substantially free from tar, and said endothermic engine and/or turbine and/or similar, being fed directly by means of said light gas.

13. Plant, according to claim 12, characterized by the fact that said plant comprises a zone for the production of the electrical energy (9), said zone comprising devices that are able to transform the natural thermal energy of the gas into mechanical energy and afterwards into electrical energy, as otto cycle engines, a turbine and/or similar.

14. Plant, according to claim 13, characterized by the fact that said zone for the production of electric power (9) comprising preferably an endothermic engine

(91) and an alternator (92) joint to said endothermic engine (91).

15. Plant, according to one or more of the claims from 12 to 14, characterized by the fact that said R.D.F., or anyway, said combustible of the plant feeds said gasifier (1), in particular said two-stage gasifier (1) by means of a feeding system.

16. Plant, according to one or more of the claims from 12 to 15, characterized by the fact that said feeding system comprises a stocking and feeding device (2), where said stocking and feeding device (2) comprises at least a plated container, opened in the upper part to allow the loading of the material and comprises also a belt (22) to convey the material toward the belt, preferably a loading slanting belt (3) for a skip (4).

17. Plant, according to one or more of the claims from 12 to 16, characterized by the fact that said loading system comprises a loading skip (4), or rather a device based on a container (4), so called skip, constrained to at least one, preferably two guides (41), that drive said skip (4) according to a vertical route, preferably parallel to said gasifier (1).

18. Plant, according to one or more of the claims from 12 to 17, characterized by the fact that said skip (4) reaches an end of stroke, makes a rotation on the horizontal axis and releases the material on the belt (5), said belt (5) belonging to the feeding group (6) of the gasifier (1).

19. Plant, according to one or more of the claims from 12 to 18, characterized by the fact that said feeding group (6) of the gasifier (!) comprises said belt (5) that conveys the material in a double feeding valve, preferably of oleodynamic controlled type.

20. Plant, according to one or more of the claims from 12 to 19, characterized by the fact that said double feeding valve comprises preferably a charging door (61), a chamber (62) sealed by two hatches (63, 64) that open alternatively and are able to avoid the downflow of the gas and/or the entering of the atmospheric air.

21. Plant, according to one or more of the claims from 12 to 20, characterized by the fact that said two-stage gasifier (1) is a two-stage gasifier that uses the fuels that have an elevated carbon content, as the RDF

22. Plant, according to one or more of the claims from 12 to 21, characterized by the fact that said two-stage gasifier (1) comrpises in the upper part a still (11) and a body zone (21).

23. Plant, according to one or more of the claims from 12 to 22, characterized by the fact that the pyrolisys of the R.D.F. and the distillation of the tar happen inside said two-stage gasifϊer (1) in a controlled way, maintaining a temperature when the front-end gas exits, preferably around 150°C.

24. Plant, according to one or more of the claims from 12 to 23, characterized by the fact that said temperature is controlled by passing a certain quantity of gas, coming from the gasification zone, through the layer of combustible that is found in the distillation zone.

25. Plant, according to one or more of the claims from 12 to 24, characterized by the fact that the lower section (31) of said gasifϊer gasifies some combustible that has already ceded the distillates and, in particular, is free from tar.

26. Plant, according to one or more of the claims from 12 to 25, characterized by the fact that the heating of said still (11) happens in a direct and indirect way: direct, through the gas that goes through the R.D.F.; and indirect, through the remaining part of the gas that licks the walls of said still (11).

27. Plant, according to one or more of the claims from 12 to 25, characterized by the fact that said front-end gas is made of the products of the gasification and distillation of the RDF and from the gas coming from the zone below the gasification and said light gas, coming from the gasification zone, is free from the pyrolisys' products, tar and oil and able to be sent into endothermic engines.

28. Plant, according to one or more of the claims from 12 to 27, characterized by the fact that the extraction of the ashes from said two-stage gasifier is automatic, in function to the level reached by the same within the gasifier (1); or rather, said gasifier (1), the ashes are comprised between the rotating grid (41) and the combustion's zone; said gasifier (1) comprises also thermocouples of which one of them is installed under said grid (41) and a second one of the thermocouples is installed on the upper part of the ashes' zone and, and being fitted an ideal level of ashes layer in the gasifier so that it protects said grid and it is not to much high to occupy the combustion's zone,when the layer of ashes is too low, the lower thermocouple underneath the grid will flag with a raised temperature ,while, if the layer of the ashes is too high, the upper thermocouple will flag with a decreased temperature, in a way that the extraction of the ashes, and, therefore, the rotation of the grid will be adjusted in relation of such taken temperatures, in an automatic way.

29. Plant, according to one or more of the claims from 12 to 28, characterized by the fact that the volume ratio between said light gase and said front-end gas is adjustable, as a function of the draught and/or of the adjustment of two valves placed on each of the two tubings, or rather of the valve of the front-end gas and the valve of the light gas, and preferably the ratio is 4 (light gas): 1 (front-end gas).

30. Plant, according to one or more of the claims from 12 to 29, characterized by the fact that said light gas exits from said gasifier at a temperature of about 650 °C and presents a n.c. v. of about 1.290 kcal/Nmc.

31. Plant, according to one or more of the claims from 12 to 30, characterized by the fact that said plant comprises also a cooling and dusting zone (8) comprising preferably a water/gas exchanger (81) and a filter, in particular a bag filter (82).

32. Plant, according to one or more of the claims from 12 to 31, characterized by the fact that said front-enmd gas exits from said gasifier preferably with a calorific value of about 1.340 Kcal/Nmc and with a temperature of about 160÷200 ⁰C.

33. Plant, according to one or more of the claims from 12 to 32, characterized by the fact that said plant comprises a combustion chamber (71) for the front-end gas able to clean said front-end gas from the oily and tarry residuals by burning the front-end gas at temperatures greater that 850°C for at least 2 seconds.

34. Plant, according to one or more of the claims from 12 to 33, characterized by the fact that said plant comprises a post-combustion chamber (72), comprising a free level of 02 > than 6% and able to use the hot smokes produced by said combustion to generate thermal power and/or hot water and/or steam.

35. Plant, according to one or more of the claims from 12 to 34, characterized by the fact that said plant comprises a detarring refractory chamber for said front-end gas, where said front-end gas remains in said refractory chamber at high temperatures, for example 900°C, for at least 2 seconds; said refractory chamber comprising a burner that uses methane gas or LPG or similar and uses as comburant, oxygen and where the quantity of the sent oxygen represents the stoichiometric air for the methane or LPG or similar combustible , but not sufficient to burn the syngas contained in the same chamber.

36. Plant, according to one or more of the claims from 12 to 35, characterized by the fact that the front-end gas is also dusted and therefore advantageously mixed to said light gas.

37. Plant, according to one or more of the claims from 12 to 36, characterized by the fact that the smokes exiting from said endothermic engine and/or turbine and/or co-generator and/or similar, said endothermic engine and/or turbine and/or co-generator being devices that are able to transform the potential chemical energy of the light gas into a mechanical energy and afterwards into electric energy, are mixed to said front-end gas exiting from the gasification process.

38. Plant, according to one or more of the claims from 12 to 37, characterized by the fact that said two-stage gasifier is fed with R.D.F.-Q according to rale Uni

9903-1.