EP0819156A1

EP0819156A1 - Method and device for producing fuel by continuously pyrolysing crushed or pasty waste

Info

Publication number: EP0819156A1
Application number: EP95912305A
Authority: EP
Inventors: Osvald Minghi; Jacques Froidefond; Guy Chaplot
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-03-18
Filing date: 1995-03-13
Publication date: 1998-01-21
Anticipated expiration: 2015-03-13
Also published as: EP0819156B1; WO1995025779A1; FR2717490B1; AU1953895A; FR2717490A1; DE69514255T2; ATE188236T1; DE69514255D1

Abstract

Equipment for upgrading waste to produce fuel is disclosed. The fuel production device of the invention includes at least one reactor (20) provided with at least two corotating mixing screws (7), enclosed in a sealed chamber (25) and divided into as many compartments (1, 2, 3, 4, 5...) as there are processing steps, which compartments are arranged one after the other in the order of said processing steps with the mixing screws (7) extending therethrough; at least one sealed inlet (10, 21) for feeding waste (6) and additives (9) into the first compartment (1); units (11, 12, 13, 14, 15...) for creating a vacuum in each compartment of the reactor (20); and at least one heater (17) for heating the third compartment where the material is pyrolysed (3) at 200-800 DEG C.

Description

Method and device for producing fuel by continuous pyrolysis of ground or pasty waste

The present invention has pou ^ a method and fuel device by continuous pyrolysis of crushed or pasty waste.

The technical sector of the invention is the field of the production of waste recovery equipment for the production of energy.

One of the main applications of the invention is the treatment of crushed or pasty industrial waste, but other applications are possible for other types of waste, also crushed or pasty, to transform these, without atmospheric pollution, into usable dry fuel. to produce energy at a profitable production cost, also with the minimum of residual pollution, either on site and immediately, or in any other place and at any time desired, the overall energy balance of the transformation of waste by the treatment method according to the invention, and the production of recoverable energy thereafter, being positive. Many processes and equipment are known which propose to treat waste to avoid its landfill which, on the one hand, degrades the environment on large surfaces, on the other hand, constitutes indirect sources of significant pollution, and finally represents increasingly heavy costs for the communities and / or manufacturers concerned. Indeed, both by political will and at the request of the populations and the awareness of all, industrialized countries are forced to protect their environment more and more and impose on all producers of waste to develop and set up treatment centers. However, these represent a significant investment which may be higher than the cost of landfilling: also, so as not to burden the funding which is then often borne by the communities, and on the contrary encourage the persons concerned to decide on such investments, studies and tests have been carried out for a few years to enhance the treatment of waste so that the whole operation is economically balanced.

For this, four sectors have been explored and have enabled the study and development of four types of process and equipment offered to date:

- incineration which is the most industrialized method at present on a large scale, but which does not allow a true recovery, even if one can recover, but directly on the spot and without possibility of storage, part of the calories , usable then in fact only in urban or collective heating and which in summer are then wasted anyway, or in random production of electrical energy in periods of time which are not advantageous for the exploitation of this energy: more, this process _. generates on the one hand, pollution by the discharge of toxic gases into the atmosphere, and on the other hand, combustion by-products which must be stored and which, over time, can be dangerous; moreover, the processing temperatures are quite high, which, combined with the uncontrolled toxicity of the treated products, deteriorates the equipment quickly by accelerated wear and leads to fairly high operating costs;

- Anaerobic fermentation of organic matter in the liquid phase, in particular household waste: there are a few units operating according to this process, which makes it possible to produce, on the one hand, combustible gas rich in methane, and on the other hand, a ground material which, once wrung, gives a solid fuel and a digestate usable as fertilizer. However, this type of process requires a fairly complex large installation, having to resist corrosion and requiring an energy supply and additives with fairly bulky equipment, for recovery and storage of gas; in addition, it can only treat certain types of mainly household waste.

- Accelerated mineralization by chemical reaction using first quicklime to decompose and transform essentially organic matter, then various other treatment stages, such as heating at medium temperature, adding other reagents, grinding, compacting in order to obtain an inert and neutral end product, theoretically reusable, such as building bricks. Several methods have been studied in this type of processing, some of which have been the subject of patent applications, such as FR applications. 2 472 421 from Mr. GER0NIM0, FR.2 583 742 from LOMA FINANCE, EP. 427 899 from the Swiss company GOMACRIS, citing all three for inventor Monsieur BIEZ, and that FR. 2,612,427 from the Swiss company CATREL. However, none of the treatments described in these applications has really been applied in significant industrial installations: all these processes are in fact derived from experiments and results reports without any real explanation of the physico-chemical stages which have made it possible to obtain these results; the descriptions come from observation only and do not allow industrial repeatability: the products obtained cannot therefore have the characteristics announced in a certain and almost constant manner, and for large scales; in particular, the characteristics obtained depend on the one hand on the composition of the treated waste, some patents of which even require, for example, at least _0% of cellulosic material, which greatly limits the application of such processes, and on the other hand on the other hand, reasons for implementation, linked to the empiricism of the conditions of the experiments, and which therefore do not allow true application on an industrial scale. Furthermore, these treatments do not remove non-ferrous metals or heavy metals, whatever their form, such as organometallic complexes which are however a very significant source of pollution.

- The transformation by decomposition at very high temperature by thermolysis or pyrolysis of waste, in order to destroy certain toxic products thereof and to obtain a combustible material either immediately usable or reusable later, as described and taught in many recent patents , because it is a new and promising development in which the present invention is situated: we can quote in this context the request FR.2 683 546 from the Spanish company SISTEMAS IBERICOS DE RESIDUOS on "a manufacturing process solid combustible material from urban waste "which produces hot pellets at temperatures above 850 °; Application FR.2 679 009 from IFP and CGC ENTREPRISE entitled "Process and device for treating waste by direct contact" comprising a drying step, a thermolysis step by contact with hot gases with low oxygen content and a step of dechlorination by washing; or even in the requests FR.2 671 990 and FR.2 674 149 by Mr. CHAUSSONNET, there is described a "system for the treatment by thermolysis under vacuum of products (liquids or gases for the first request and solids for the second), the rejection of which is detrimental for the environment ": the vacuum allows an absence of oxygen preventing certain chemical reactions of oxidation but the system described requires a large reaction chamber and fairly significant energy supply, and does not allow simultaneous treatment of waste of different origin, heat transfers being difficult to control in a vacuum given the installation described.

All these devices and methods, in fact require a significant external energy supply which is not offset by the value of the products recovered at the device outlet, even when these products are fuels which can generate energy; moreover, these systems do not eliminate the dangers of pollution by subsequent leaching of heavy metal complexes which remain in the products resulting from the treatment; similarly, most of these devices and methods can still emit polluting and / or toxic gases, either during the manufacture of the sought fuel product, or during the combustion of these fuels obtained, and for which no treatment is planned, as in the incineration where this release is even greater, due to the incomplete combustion of certain materials such as paper,

PVC, etc ... which release hydrochloric acid at a rate of 7 kg per tonne of urban solid waste, for example.

Thus, the problem posed is to produce fairly compact installations which can be fixed or mobile, for processing previously crushed or pasty waste, whatever their origin but of which it is known and its general composition in order to be able to extract therefrom products at least some of which are combustible, as well as others which are reusable in any other form depending on the composition of the treated waste and whose economic market value is at least equal, if not greater, than the whole the cost of treatment, including the amortization of the investment. In addition, another objective of the invention is to reject nothing in nature, which is not polluting, both in the form of gas and of solid residues, whether during the treatment of the waste itself to produce said combustible products or other reusable residues, only during the combustion and use of the products thus obtained, in particular with regard to the elimination of any toxic gas, and the sequestration of heavy metals, so that any pollution later by the use of solid residues is discarded; this can be verified by analyzing the leaching water of the products obtained, which complies with the regulations on heavy metal content.

One solution to the problem posed is a method of producing fuel by pyrolysis of ground or pasty waste, comprising at least a first step of kneading the latter with additives including at least lime, a second step of drying the mixture, a third step of decomposition of the products of this mixture by heating at high temperature and a fourth step of additional treatment depending on the nature of the initial waste and the desired finished product, in which:

- all of the process steps are carried out in at least one reactor comprising at least two corotative kneading axes forming an Archimedes screw and enclosed in an enclosure such as for example a twin-screw device such as those described in US patents 3- + 19250 of December 31, 1968 and US 3618902 of November 14, 1969 of Mr. Ambrose K. BRENNAN; which reactor, in a preferred embodiment is divided into as many successive compartments as process steps, arranged continuously one behind the other in the order thereof and preferably crossed by the same screws or axes of mixing;

- during the first stage of the initial mixing of the waste, additives are added comprising, in addition to quicklime, metal oxides so that cage molecules or metal cation sensors are produced which trap and sequester those who might be present in the waste;

- The reaction energy of the mixture obtained in the first step is used with the ground or pasty waste and the additives, and that mechanical friction of the kneading screws to dry, in the second step, said mixture;

- the third step of decomposition of the products is carried out by pyrolysis with heating bringing the temperature of the compartment corresponding, between 250 and 800 ° C;

- all the stages of the treatment are carried out, under vacuum, between 100 and 500 mm of column of water of absolute pressure.

In a preferred embodiment, a separation of ferrous and non-ferrous metals is carried out before the first kneading treatment step, which is extracted from ground or pasty waste before their introduction into said reactor.

In a preferred embodiment, the mixture obtained in the second drying step is heated by an external energy supply if the waste has a humidity rate greater than approximately 30%, in order to help their drying.

During the third step of the process, which is pyrolysis, on the one hand, the organic compounds are decomposed in the form of condensable pyrolytic oil gas and combustible gas, on the other hand, other non-pyrolyzable compounds are sublimated which s 'evaporate under vacuum, all of these gases being recovered by at least one means for evacuating the reactor and from which the separations necessary to recover each gas for its specific use are carried out; at the end of this pyrolysis step, a solid residue is obtained which can be a fuel which is cooled during a fourth step of the process during which the reaction which started in the preceding pyrolysis step ends. .

In a specific embodiment, a final treatment step is carried out during which additives determined depending on the product are added to the residual products from the previous step, which is either directly that of pyrolysis or that of cooling intermediate desired finish and the nature of the initial waste compounds.

In a specific embodiment, said waste is ground before its introduction into said reactor by any known means giving them a particle size dimension equal at most to the thread height of the kneading screws at the inlet of the reactor; in each compartment of the reactor, the profile and the pitch of the threads of said screws may be different, and in the first mixing compartment, these preferably shear the waste into particles of less than one tenth of a millimeter.

The result is new production processes for fuel _, and devices allowing the application of such methods according to the description below and the example of the attached figure. Indeed, such methods and devices make it possible to respond to the problem posed and to achieve the objectives defined above while avoiding the drawbacks of the methods and devices known to date.

Indeed, thanks essentially to the use of two co-rotating kneading screws allowing the whole treatment to be carried out, which makes it possible inter alia to recover in the form of heat energy the mechanical friction of the latter to heat and dry the product, and also when all the stages of the process are put under vacuum, the energy balance is improved: this in fact, at least, balances and compensates for all the energy needs of the process according to the invention, thus that the investment and operating costs necessary for the execution of the present process and which may even, in certain cases, depending on the type of waste treated and recovered, in addition to the supply of combustible gas allowing said energy recovery and to obtain other combustible and / or recoverable products. All of the energy production thus recovered gives a value per tonne of waste greater than the total current cost of transport and landfill; this yield is therefore of course very attractive, especially since the methods and devices according to the invention allow the recovery to 3% by mass of the treated waste, the remaining% being residues such as inert ashes, in which metals heavy, possibly and initially present, are still present but with their toxicity inhibited by the phenomenon of sequestration; moreover, there is no release of polluting smoke into the atmosphere during the combustion of the combustible products recovered according to the process of the present invention.

Indeed, in addition to the above advantage, the vacuum allows the control and the complete anti-pollution treatment of the gases and water resulting from the process, just as the clean technology of the present invention allows '' carry out all of the treatment operations without generating pollution, without any discharge of dust or gas into the atmosphere and the fully treated waste is transformed into solid, oil, gas or water, usable in materials raw materials or property materials identical to the substituted products.

In addition, the dangers of delayed pollution by leaching of heavy metal complexes which are responsible to date, severe pollution lasting over time, are ruled out: indeed, although significant quantities of heavy metals are dispersed to date in the known processes and devices in fly ash, for example during incineration, there remain significant proportions in bottom ash in the form of metal oxides which are soluble in the aqueous phase and therefore leachable. The present invention takes advantage of the known method of sequestering heavy metals in a cage molecule such as a hydrated calcium silico-aluminate matrix, insoluble in water and resistant to corrosion: thanks to this process step included in the present invention, the heavy metals are no longer soluble in the aqueous phase and the leaching phenomena no longer have the consequence of polluting the groundwater.

The present invention also inhibits the production of any acid rejection by in situ neutralization of the acid generating compounds and the basic reaction medium is produced by the use of lime and transforms for example hydrochloric acids into saline chloride and sulfuric acids into sulfate.

Another essential characteristic of the invention is to make it possible to offer, by a simple modification of the treatment parameters in the different compartments where the different stages of the process according to the invention are carried out, a different recovery depending on the type of waste treated and according to local needs; an installation according to the invention makes it possible to treat and recycle many types of waste other than radioactive, such as residues from car wrecks, used tires, petroleum residues, forest, agricultural and urban bioraasses, household waste and residues from the paper industries , tanning, plastics, industrial, purification plants, etc. Indeed, the process according to the present invention makes it possible to choose, whatever the treated waste, and this in the same reactor, by a simple modification of the parameters and additives, and in addition to gases at least part of which is combustible, the nature of the solid product and more or less dried out, which can be indifferently used as fuel, inert materials or edaphic products such as fertilizers or composts, or a combination of gas, oil and solids, and may possibly give rise to mixed recovery in the form energy products and chemicals. In all cases, part of the products resulting from the process of the present invention, in either gaseous, liquid or solid form, is combustible.

One of the main applications of the. present invention is, as indicated in the introduction, the treatment of industrial waste, or other waste like those above, the need of the present invention simply asking them to be ground or pasty prior to their introduction into the reactor, such as defined below. The present invention thus aims to improve the existing waste treatment methods, in particular allowing continuous treatment in the same reactor, successively ensuring the functions of mixing, drying, stabilization or transformation of incoming products, which considerably reduces the installation and operating costs: the various process stages are thus grouped together in the same compact machine, also making it possible to obtain optimal compliance with the treatment parameters specific to each type of waste, which is stored in the form of program in the memory of an automaton or a microcomputer which then controls the entire device and which makes it possible to produce and extract, products, on the one hand combustible and energetic, and on the other hand inert and / or reusable for other uses; the parameters thus recorded are for example the temperature, the speed of treatment, the dosage of chemical additives and / or complementary products as well as the regulation of the internal vacuum pressure.

The device according to the invention indeed comprises a system for extracting and filtering the vapors produced, supplemented by one or more condensers, and one or more vacuum systems by pump, for example, with liquid ring.

The gases thus recovered are treated chemically in such a way that there is no acid rejection of the hydrofluoric type. sulfurous or sulfuric in the atmosphere, and that the gases collected are reusable without external pollution, nor any release of smoke or vapor, in particular by an immediate use of their energy at least of turbination. Regarding the obtained combustible products, whatever their form, they can be stored and their use can be postponed.

Another advantage of the present invention is that the basic process thereof can be dissociated from the primary preparations for pre-grinding, iron removal and demetallization: this basic process can thus be carried out in a compact reactor, the elements of which are transportable from one site to another on mobile equipment, for example.

We could cite other advantages of the present invention, but those mentioned above already show enough to prove its novelty and interest. The description and the single figure below represent an exemplary embodiment of the invention, but have no limiting character: other embodiments are possible within the scope and scope of the invention; in particular depending on the type of waste treated and the residual product that is desired, it is possible not to use one of the steps of the method and not to operate one of the corresponding compartments of the device of the present invention.

The single attached figure is a longitudinal sectional view of an example of a reactor for carrying out the process of the present invention. Beforehand and upstream thereof, the waste 6 is ground by any known means giving them a particle size dimension equal at most to the thread height of the first compartment 1 of the kneading screws 7 of said reactor 20, such as for example with a maximum volume for each grain or particle of crushed waste corresponding to a parallelepiped of 50 mm x 50 mm x 20 mm approximately, or must be in a pasty form which can be the form in which they are rejected by industry producer; similarly, upstream of the device in the attached figure, the waste 6, once ground, or put into pasty form, is freed from any possible ferrous or non-ferrous metal part, such as for example the action of a magnetic field according to any known process which even makes it possible to make magnetic and therefore eliminable by attraction, the parts which are not ferrous.

To carry out the process described above of the present invention, the fuel production device comprises at least a first step 1 of kneading them with the additives 9 including at least lime, a second step 2 of drying the mixture, a third step 3 of decomposition of the products of this mixture by heating 17 at high temperature and a fourth step 4, 5 of additional treatment depending on the nature of the initial waste and the desired finished product 19. For this, the device according to the invention comprises:

- At least one reactor 20 comprising at least two corotative kneading axes forming screw 7 of Archimedes and enclosed in a sealed enclosure 25, driven by any means of rotation 22, at the speed and with the desired and necessary and divided torque in as many successive compartments 1, 2, 3. 4, 5 --- As many steps of the treatment process, continuously arranged one behind the other in the order of said steps and crossed by the same kneading axes 7;

- At least one sealed capacity 21 supplied with two independent buffer tanks, for example by means of rotary locks 10 ensuring sealing with the atmosphere, and the introduction according to the respective desired flow rates of waste 6 and additives 9 in the first compartment 1; the device according to the present invention makes it possible to acquire a flow rate of 5 to 10 tonnes / hour of waste per continuous reactor 20; - Means 11, 12, 13. 14, 15 ... for evacuating each of the compartments of the reactor 20;

- at least one heating means 17 of the third pyrolysis compartment 3-

The first step of the process according to the invention is carried out in compartment 1, which is the so-called grinding and kneading zone between the different returning products that are waste 6 and the liquid and solid additives 9 ensuring stabilization and pollution control. and the synthesis of the molecular structures necessary for the sequestration of heavy metals according to the known process for the preparation of cage molecules, namely essentially quicklime and metal oxides whose chemical transformation and hydration allow synthesis. These additives also have secondary function of promoting the drying of wet waste.

The second step of the process according to the invention is carried out in the second compartment 2 succeeding the previous 1, and which makes it possible to obtain rapid drying by combining a pressing action promoting the extraction of liquids from the core of the material, with a heating to ensure vaporization facilitated by the vacuuming of the zone by any extractor 11. Said heating can simply be the recovery of the friction energy of the kneading screws 7 and which is sufficient when the humidity of the waste introduced 6 is less than 0%; when this rate is higher, an additional auxiliary heating 8 is necessary, such as by induction, and makes it possible to obtain the desired result.

This which is the drying of the products, must combine two phenomena which are, on the one hand the entrainment of water from the inside of the wet particles towards the outside, and on the other hand the evaporation of this surface water, which essentially depends on ambient conditions, such as relative humidity, temperature and speed: evaporation is all the more intense the lower the relative humidity of the air and the lower its temperature and speed are high. On the other hand, the circulation of water in the material is a more difficult phenomenon to control and it occurs systematically from the hot parts towards the cold parts and from the wet zones towards the dry zones. To improve the entrainment of water towards the periphery of the particles to be dried and where evaporation occurs, it is therefore necessary to bring the interior of the particles to be dried to a higher temperature than that prevailing at their surface. This can be improved by reducing the pressure in the enclosure, such as by achieving partial vacuum precisely by any means 12 making it possible to maintain an absolute pressure of 100 to 500 millimeters of water column in compartment 2 and preferably 150 millimeters of water column, which improves the heat transfer coefficient.

Reducing the pressure also allows energy savings by reducing the enthalpy of vaporization, that is to say the amount of energy required for the passage of water from the liquid state to the gaseous state, and a pressure is sought which makes it possible to obtain this vaporization with the only energy mechanical grinding and transport of the material naturally transformed into heat in the reactor by said kneading screws 7.

In addition, the fineness of the grinding and possibly the quality of the preliminary kneading with the additives, thanks to the use of such kneading screws 7, especially when it is a twin screw, combined with the vacuum, the pressing and the decrease in surface temperature due to the significant heat loss caused by vaporization, make it possible to considerably accelerate the drying time, which can then commonly be less than 60 seconds.

It is important to note that the vaporization rate is directly linked to the average particle size and that the smaller the average diameter, the shorter the path that will allow the water molecules to exit their solid matrix, and the more the greater the diffusion of water out of the particle, the better the efficiency of evaporation.

We may only want partial drying in certain cases, such as for example when we want to produce edaphic products at the end of the process. The third step of the process according to the invention, carried out in compartment 3. is a variable temperature treatment zone, depending on the desired final product 19: this temperature can vary over a wide range, such as 200 to 800 ° C., and thus reaching the conventional pyrolysis temperatures; depending on the waste treated, in fact a maximum of 650 ° C. would be sufficient thanks to the present invention, since it is in a vacuum. The additional heating 17 required is provided from the outside by an electromagnetic induction system for example, or by a system such as heating rods. The objective is to be able to carry out a total or partial pyrolysis of the waste, which can usefully lead to a separation of certain metals present, by vaporization / condensation under vacuum, or sublimation.

Pyrolysis at high temperature and under low oxygen pressure, allows rapid separation by distillation of condensable vapor resulting from the decomposition of organic materials. The secondary oxidation reactions which characterize pyrolysis are minimized in the present invention; and the condensates obtained composed of primary fragments are of better quality. We can control, thanks to the choice of the temperature and pyrolysis pressure couple and the material flow which can be advantageously modulated according to the profile and the speed of rotation of the kneading screws 7. the materials that we want to keep in the residual product 19 and select those that we want to sublimate or decompose, since each has its own temperature.

Vacuum pyrolysis is typically carried out in the present invention, at temperatures of the order of 450 ° C. for an absolute vacuum pressure of the order of 150 millimeters of water, or 15 kPa, but could be also in a range of 10 to 0 kPa. These operating conditions, notably more favorable than those found during conventional pyrolysis at atmospheric pressure and incineration, make it possible to obtain large quantities of pyrolytic oil as well as solid residues which have the properties of reactivity. superior to fuels such as coal from processes known to date.

Depending on the waste 6 treated and the desired products 19. it may be sufficient to work at a temperature below that reached during pyrolysis, for example for the manufacture of solid fuel or building materials without obtaining gas. This compartment 3 is also connected to a vacuum installation 13, different from the previous one, because the condensed vapors are of different types. The fourth step of the process according to the invention is carried out in a compartment 4 which is essentially a cooling and final degassing zone which can also be connected to a vacuum installation 14, which can be the same as that of the compartment previous 3 • The fifth step of the process according to the invention is carried out in a compartment 5 which is an ultimate treatment zone allowing, by possible addition of solid and / or liquid additives 16, to produce the desired finished product by enriching it for example, such as for fuels to increase their calorific value, edaphic products, their enrichment in nitrogen, phosphate and potassium, nutri-elements, trace elements, etc., or by neutralizing them by acid-correction basic pH for example the 15

correction of the conductivity or that of the anion exchange capacity.

These additives 16 are delivered from any buffer storage means 23 closed by a metering and sealing valve 10 and supplying the desired quantity to said compartment 5. The evacuation of residual terminal products 19 to all evacuation system is produced by any watertight means 24, such as a rotary valve.

The different zones and compartments of the reactor 20 are therefore connected to different degassing and vacuum means, preferably by means of one or more condensers and one or more liquid ring pumps. The condensers may also allow the injection of one or more bactericidal, fungicidal, algicidal, etc., or neutralizing substances, depending on the temperature adopted in the process and the type of waste 6 introduced in order to eliminate any toxicity of the gases. recovered products.

Each compartment of the reactor 20 is equipped with a temperature and / or internal humidity pressure sensor 18, in order to transmit all of the temperature pressure and humidity values, to a central computer which is programmed to control all the means of operation of said reactor 20 according to the process of the present invention, for a treatment defined with respect to the desired outgoing products 19. as a function of the composition of the incoming waste 6, such as for example, always with a part of the products obtained in fuel:

- for organic or non-organic sludge 6: fuel, with or without edaphic products;

- for some. industrial sludge: fuel with or other recyclable materials; - for bio-medical waste: fuel and products for cement manufacturers;

- for tires: fuel and carbon black, and / or pyrolytic oils rich in various chemicals;

- for household waste: fuel and / or edaphic products;

- for scrap scrap cars: fuel and metals, and / or specific chemicals; - for petroleum residues: fuel with or without other specific chemicals.

By way of example, during the tests carried out according to a method and a device of the present invention, examples of yield by vacuum pyrolysis can be presented as a percentage of the initial weight treated, such as:

TYPE SOLID OIL RESIDUES WATER GAS

Used tires 55 35 (D 2 8

Petroleum residues 30 18 50 2

Biomedical waste 50 8 37 5 Residues from car wrecks 18 62 (2) 16 4

Wood residue and bark 45 30 15 10

Domestic waste 46 33 10 11

(1) includes 3 / - + carbon black and 1/4 steel

(2) contains around 50% of easily recoverable metals such as iron, copper, aluminum and zinc.

A reactor 20 as described above and whose vacuum compartments correspond to the stages according to the method of the present invention, can also be divided into several successive reactors corresponding to the combination of one or more of said compartments, and always arranged continuously but with drive systems which can then be different. Some of these compartments can even be placed not under vacuum but at ambient pressure or even under overpressure, as can the entire reactor in its embodiment as shown in the attached figure, but then with a different objective of treatment of waste.

Claims

CLAIMS 1. Method for producing fuel by pyrolysis of crushed or pasty waste (6), comprising at least a first step (1) of kneading thereof with additives (9) including at least lime, a second step (2) drying the mixture, a third step (3) of decomposition of the products of this mixture by heating (17) at high temperature and a fourth step (4, 5) of additional treatment depending on the nature of the initial waste and of the desired finished product (19), characterized in that: - all the stages of the process are carried out in at least one reactor (20) comprising at least sets of corotative kneading axes (7), forming enclosed Archimedes screws in an enclosure

(25);

- during the first step (1) of initial kneading of the waste (6), additives (9) are added comprising, in addition to quicklime, metal oxides so that cage molecules or metal cation sensors which trap and sequester those which may be present in the waste (6);

- The reaction energy of the mixture obtained in the first step (1) is used with the ground or pasty waste (6) and the additives (9). and that of mechanical friction of the kneading screws (7) to dry, in the second step (2), said mixture; the third step (3) of decomposition of the products is carried out by pyrolysis with a heater (17) bringing the temperature of the corresponding compartment, between 200 and 800 ° C;

- all the steps (1, 2, 3. 4. 5 ---) of the treatment are carried out, under vacuum, between 100 and 500 mm of column of water of absolute pressure.

2. Fuel method according to claim 1, characterized in that one uses a reactor (20) composed of a single enclosure (25) and divided into as many successive compartments (1, 2, 3. 4. 5- -) That many process steps, continuously arranged one behind the other in the order of these and crossed by the same kneading axes (7).

3- A fuel production method according to any one of claims 1 and 2, characterized in that prior to the first step of mixing treatment, a separation of ferrous and non-ferrous metals, which are extracted from ground or pasty waste (6) before their introduction into said reactor (20).

4. A fuel production method according to any one of claims 1 to 3. characterized in that the said waste (6) is ground before its introduction into the said reactor (20) by any known means giving them an equal particle size dimension maximum at the thread height of the kneading screws (7) at the inlet of the reactor (20).

5- fuel production method according to any one of claims 1 to 4, characterized in that the mixture obtained in the second drying step (2) is heated by an external energy supply (8) if the waste has a humidity level higher than about 30%, to help their drying.

6. A method of producing fuel according to any one of claims 1 to 5. characterized in that during the third step (3) of pyrolysis, on the one hand the organic compounds are decomposed in the form of pyrolytic oil gas condensable and combustible gas, on the other hand, other non-pyrolyzable compounds are sublimated which evaporate under vacuum, all of these gases being recovered by at least the means (13) of evacuation and from which performs the separations necessary to recover each gas for its specific use, and at the end of this pyrolysis step (3). a solid residue is obtained which can be a fuel which is cooled during a fourth step (4) during which the reaction which started in the previous step (3) ends •

7. Fuel production method according to any one of claims 1 to 6, characterized in that a final treatment step (5) is carried out during which the residual products from the previous step are added to (3) 4) additives (16) determined according to the desired finished product (19) and the nature of the initial waste compounds (6).

8. Device for producing fuel by pyrolysis of ground or pasty waste (6) according to a process comprising at least a first step (1) of kneading the latter with the additives' (9) including at least lime, a second step (2) of drying the mixing, a third step (3) of decomposition of the products of this mixture by heating (17) at high temperature and a fourth step (4, 5) of additional treatment depending on the nature of the initial waste and the finished product (19) desired, characterized in that it comprises:

- At least one reactor (20) comprising at least two corotative kneading axes forming screw (7) and Archimedes enclosed in a sealed enclosure (25). and divided into as many successive compartments (1, 2, 3. 4, 5 ---) As many steps of the treatment process, continuously arranged one behind the other in the order of said steps and crossed by said screws ( 7);

- at least one sealed introduction (21) of the waste (6) and the additives (9) into the first compartment (1);

- Means (11, 12, 13. 14, 15- ..) for evacuating each of the reactor compartments (20);

- at least one heating means (17) of the third pyrolysis compartment (3) •

9- Fuel production device according to claim 8, characterized in that it comprises upstream of said reactor (20) a known means of separation of ferrous and non-ferrous metals which are extracted from the waste (6) ground or pasty , before their introduction into said sealed supply means (21) of said reactor (20).

10. Fuel production device according to any one of claims 8 and 9. characterized in that it comprises upstream of said reactor (20) a known means which grinds said waste (6) before their introduction into said means (21 ) supplying said reactors (20) and giving them a particle size dimension equal at most to the thread height of said kneading screws (7) in the first compartment (1).

11. Fuel production device according to any one of claims 8 to 10, characterized in that the profile and the pitch of the threads of said kneading screws (7) are different in each compartment of the reactor (20), and that in the first mixing compartment (1), its profile and its thread pitch are determined to shear the waste (6) into particles of less than a tenth of a millimeter.

12. Fuel production device according to any one of claims 8 to 11, characterized in that it comprises a heating means (8) of the compartment (2) which allows the heating of said compartment when the humidity of the waste introduced (6) is more than around 30%.

13- Fuel production device according to any one of claims 8 to 12, characterized in that it comprises a last compartment (5) and a sealed means (10, 23) for introducing additives (16) into said compartment (5). which additives (16) being determined according to the desired final product (19) and the nature of the compounds of the initial waste (6).

14. Fuel production device according to any one of claims 8 to 13. characterized in that it comprises at least sensors (18) of temperature pressure and / or interior humidity in each compartment of the reactor (20) and a control computer connected to the various sensors and which is programmed to control all the operating means of said reactor (20) according to the treatment method of any one of claims 1 to 7 defined with respect to the desired product ( 19) depending on the composition of the incoming waste (6).

15. Fuel production device according to any one of claims 8 to 14, characterized in that the drive and vacuum means (13. 1 * 4) are connected to a condensing installation and separation of gas for decomposition, sublimation and evaporation of said corresponding compartments (3, 4) for thermal use to produce electricity usable for the operation of the device and / or outside.