WO2004028715A1 - Method and installation for destroying, neutralizing, sterilizing household waste by solidification - Google Patents

Abstract

The invention concerns a method which consists in dumping household waste in bulk in a hopper (1) and subjecting it to plastic bag stripping (3) and removal of metal scrap contained therein (6) before being subjected to three successive grinding processes (8, 10, 12) and then introduced into homogenizing mixers (11, 14, 15) with simultaneous addition of mineral reagents (ACM) of CaCo3 and CaO type; after impregnation the products are transferred to a hydraulic homogenizer (18) then sterilized in thermal chambers (19), desiccated and stabilized in thermal stabilizing double-walled heated chambers (20) provided with zones for heating, burning, recovering vapours and condensates, cooling, and thereafter the products are stored as such to be used as fillers in building materials, or densified (24) into balls or blocks. The end products (balls or blocks) are sterile, stable, solid hence inert and harmless to the environment. The inventive method constitutes an alternative to landfilling and incineration and enables upgrading of the resulting products while providing a solution for environmental protection.

Description

 PROCESS AND PLANT FOR THE DESTRUCTION OF NEUTRALIZATION STERILIZATION BY SOLIDIFICATION OF HOUSEHOLD WASTE

The present invention relates to the field of household waste and relates more particularly to the treatment of household waste and organic waste according to a process involving sorting, grinding, mixing and then impregnation with mineral and chemical products then densification and thermal operations with biological sterilization and stabilization with a view to, on the one hand, obtaining final products reduced in stable volumes that are biologically inert and solid, while respecting and protecting the environment while securing landfill, or even eliminating it, by admitting products from the process into the composition of building materials as a filler, also eliminating incineration and other known operations for treating household waste.

The process which is the subject of the present invention does not take into account the recycling of the plastics which are integrated into the process, nor of the other materials, non-ferrous, glass, except the ferrous which are themselves sorted and extracted from the process chain, all waste is admitted to the destruction and neutralization process and more specifically, plastics by successive shredding and by thermal reduction,

OJ creep, under an atmosphere charged with CaO and CaCo3, avoiding the accidental emission of gaseous and harmful flows, since it is carried out under closed enclosures and reactive neutralizing atmospheres.

We noticed that the recyclable materials were always soiled and that industrialists were not in favor of using soiled products in their manufacturing, so we had to review this recycling policy and integrate it into the process. as charges these non-recyclable products.

The process allows the destruction the neutralization the sterilization the stabilization, o by solidification of the waste introduced into the kinematics which constitutes the process.

The method and the installation according to the invention were imagined and then perfected. Certainly, as will be seen below, the process calls, in several of its phases, on means the principle of which is known per se and which, for many, are already in the public domain, such as: sorting recoverable materials such as iron, non-ferrous materials and glass, grinding operations; mixtures of ground products with powdery mineral reagents containing in particular lime, calcium carbonate, hydraulic and water-repellent agents; heat treatments of materials; recoveries of final products which, pulverulent or o agglomerates, can be recovered by entering into the composition of materials and are rendered inert.

It is for this purpose, thanks to a judicious combination of means, the scheduling of which was not a priori predictable, then thanks to the optimization of each of the essential parameters in the different phases that the associated process and installation which are proposed here made it possible to satisfy all the requirements for a reliable and economical solution making it possible to reduce the volume of waste, recover as much as possible and ensure effective environmental protection.

The process has the advantage of destroying and neutralizing plastics without combustion only by creep, under a neutralizing reactive charged atmosphere, within closed enclosures, therefore without external release of gaseous and aqueous effluents; the treatment of woody organic matter according to the process allows a reduction in the particle size spectrum and integration into the process by allowing a homogenization of the mass and a better resolution of the recovery of the mass as a charge of materials, but also sterilization and stabilization of this waste presenting a guarantee for environmental protection due to its inert state.

According to its most general definition, the method according to the invention is characterized by the combination of the following successive steps, carried out from the collection and reception of household waste containing, inter alia, plastic bags: a) bagging of waste by laceration bags, then primary stripping of bagged waste with ferrous recovery; b) primary grinding of desensed waste with recovery of ferrous and non-ferrous non-ferrous materials; c) mixing and homogenization of the ground waste with the addition of first reagents then transfers; d) further grinding of the waste loaded with reagents, then transfer; e) then mixing and kneading with the addition of new reactive charges, then transfer; f) new grinding then transfer; g) homogenization under high hydraulic pressure and further addition of mineral fillers; h) transport of products under heating tubes and advancement of said products by hydraulic pressure; i) then after this sterilization and partial drying; j) stabilization and drying in closed thermal enclosures, by indirect heating with heat transfer thermal fluid (oil) then transfer to several zones with temperature regulation and optimization systems, separation of fines and vapors and condensation thereof; k) then transport of the dried powder; at the end of the heat treatments densification of the products after impregnation of mechanical and water-repellent binders to obtain inert solids (balls or blocks) which can be stored and or landfilled in this densified form, or, these pulverulent products treated separately by the 'intermediary of a refiner to obtain a fine, allowing recovery as a filler in the composition of materials.

The primary grinding is provided to obtain a particle size conditioning of the order of approximately 50 mm, followed by a second grinding operation under mineral loads to obtain a conditioning of the order of approximately 15 mm, while the third grinding before the said homogenizer is used to refine the particle size in order to obtain a particle size of the order of 3 mm, the refiner is used if one is not using the agglomerator to produce a fine entering as a filler in the composition of materials. The use of mineral reagents allows, in a manner known per se, on the one hand to destroy, desiccate, sterilize and stabilize organic matter (action of quick lime Cao combined with calcium carbonate, CaCo3) by exothermic reactions and, d On the other hand, to assume the desiccation of the fresh and wet waste in order to put it in condition before the admission to the crushers, then to the thermal enclosures.

Of course one can, if necessary, add a make-up water (H20) ^' and or sludge from a treatment plant, or even reactive charges at the time of admission to the hydraulic homogenizer.

Said mineral reagents, essentially based on quicklime and calcium carbonates, may also contain sulphates, silicates and or chlorides, calcium or other adjunct products such as; treatment plant sludge, gypsum, clay, in accordance with a particularly advantageous embodiment of the invention, after said mixers and kneaders with the second addition of mineral reagents, it is advisable to add to the fine mixture which enters the homogenizer a new charge of quicklime, to complete the destruction of organic matter by an oxidizing and hygienic exothermic reaction.

The basis of the treatment focused on the reduction of the spectrum of waste, then came the treatment phases by adding reactive mineral fillers and the thermal phases to obtain inert pulverulent and densified products. You should know that the use of quicklime (CaO) for the destruction and sterilization of organic bodies is known per se, that lime is used in the composition of stones such as: marble, plaster, building stone, cements and concretes, mixed with sand and water, it forms materials which harden in air.

The use of calcium carbonate CaCo3 ensures several essential functions among others allows the homogenization in water content (H2O) contained in the waste and decompose this water in reaction with its oxide, lime.

The amounts of mineral reagents are suitable for those skilled in the art and always greater than 5% of the weight of the waste. In practice, the addition of the first reagents corresponds to ranges of approximately 10 to 15% of CaCo3 (relative to the weight of the waste) and 0.5 to 5% of CaO. The addition of said second mineral reagents corresponds on average to 3-10% of CaCo3 and 3 to 15% of CaO, before heat treatment and that the water-repellents are introduced in doses generally between 0.5 and 5% of the weight of the waste and products obtained and admitted to this treatment. The details corresponding to the other essential parameters of the process will be explained later in the description of the implementation and operation of the operating process.

The invention also relates to an installation for the treatment of household waste according to the abovementioned process and which is characterized in that it essentially comprises: at least one hopper for receiving bulk waste; a means of automatic bagging of plastic bags and papers, by symmetrical and asymmetrical lacerating discs mounted in the form of diabolos and reverse on damped shaft with vibrating advancement and ejection sole, on transfer mat; a weight-deflection electromagnet with ferrous recovery; a spectrometric detector with memory center; an emergency transfer conveyor with said evacuation (left-right) followed by a first shredder, with recovery of unburnable, ferrous or non-ferrous materials including a calibration grid; after transport on a conveyor belt equipped with a magnetization drum, a second ferrous sorting electromagnet with rotating band and ejection nozzle; a first mixer-homogenizer of the waste with introduction of said first powdery mineral reagents; then a second grinding of the prepreg products; then a transfer mat; leading to a second mixer-homogenizer with admission of mineral reagents; then to a third mixer-homogenizer; feeding a third crusher; transfer means, conveyor, vibrating corridor or screw leading to a hydraulic homogenizer with new addition of mineral reagents; a set of chambers and thermal cells with several zones and several stages, provided with double jacket with circulation of heat-transfer fluid connected to an energy generator; a set of dedusting and separation of fines and evacuation of mist then condenser of mist and decantation; means for transferring the pulverulent and dried products with recovery in silos and treatment of all or part of these products by impregnation means of the mechanical and water-repellent binders type; means of densification, by mechanical or hydraulic press, of the impregnated products to obtain balls and or blocks; transfer means for said pulverulent products and the balls or blocks then elevation silage leading to storage silos for the pulverulent products and balls and or blocks; series of silos are also provided for the storage of said mineral reagents.

The standard diagram, in accordance with the invention and with the arrangement of the installation, has been defined on the single sheet appended to which has been attached, in the present application, the list of all the references corresponding to the said sheet.

The waste treatment chain, as shown, will now be described with its main means and its operating modes.

Vehicles or bins for collecting or transporting household waste in bulk unload their contents into the hoppers (1) for unloading and receiving. The contents of the hoppers are poured onto an extractor conveyor or motorized transfer conveyor (2) on the path of which a bag opener (3) has been implanted, a vibrating ejection and transfer trough (4) an esse transfer conveyor (5) and a weight undercarrier (6). The bag opener is made up of an inverted U-shaped cell fixed to the frame of the conveyor, a cell which receives motorized lacerating discs, mounted in asymmetrical and symmetrical diabolos on damped transmission axes, this bag opener (3 ) is positioned in reverse U above the conveyor and can be completely dismantled or retracted, manually or automatically. The defogger (6), installed at the head of the chain, is advantageously constituted by an electromagnet by weight working above the circulating layer of waste, the ferrous is discharged in an aluminum or composite materials hopper with evacuation in a container.

Once this first operation has been carried out, admission or refusal to the treatment chain is ensured by the so-called left-right transfer conveyor (7), the major heavy part of the ferrous metals being extracted, the waste is admitted into a first crusher (8 ) of percussion, hammer and grid type or the reduction in particle size corresponds to approximately 50mm. After the conveyor belt transfer to esse (9), a second stripping is advantageously carried out by rotary electromagnet (10), then the waste is admitted into a mixer-homogenizer (11) or simultaneously the first mineral reagents are added and then the the ground materials, pre-impregnated at the end, are introduced into the first mixer (11) advantageously in a second mill (12) to obtain a particle size of approximately 15 mm and then again transfer by conveyor belt (13) introducing the said waste and products in a second mixer-homogenizer (14) or are added the additions of mineral reagents or (MCA) consisting essentially of 3 to 8% (weight) of CaCo3 and 0.5 to 4% of Cao relative to the weight of garbage. This rotary type mixer or double screw or more, allows impregnation of waste.

The pre-impregnated waste is then introduced into a third mixer-homogenizer called a latency silo (15) of rotary or screw type or advantageously the mass of waste remains for 20 to 30 minutes, then again this mass of waste is introduced into a third mill (16) for example with knives and knives against so as to obtain a particle size of about 3 to 5mm.

Next, a transfer of the products is carried out, for example a carpet or Archimedes screw (17) introducing the said products into a hydraulic mixer homogenizer (18) or precisely and advantageously the balance of the pre-defined mineral reagents (MCA) is introduced. in proportions for example from 4 to 10% of Cao for 3 to 8% o of CaCo3, relative to the weight of the products admitted into the process and possibly of water (H2O) or advantageously of the sludge from a purification station if humidification seems necessary. According to the process, all of the products and additions (ACM) arrive in the homogenizing mixer (18) of the hydraulic cylinder type with airlock and presser then is introduced into a thermal sterilizer (19) with heat transfer fluid of the tube bundle type. double jacket with variable and adjustable temperature range between 180 ° and 220 ° Celsius. In accordance with a characteristic of the invention, the hydraulic homogenizing mixer (18) for sterilization and its thermal cell (19) for sterilization as well as the thermal chambers with stages (20) for stabilization and drying, are constituted by double bodies envelope in which circulates a heat transfer fluid essentially a thermal oil, oil which is heated by the energy generator (28). Thus the heating is carried out by conduction and convection, it is therefore possible to achieve good control and perfect regulation of the temperatures which can reach, if desired, temperatures of the order of 225 ° Cefsius. Temperatures below the emission and release of toxic gases from plastics.

According to another advantageous characteristic, the hydraulic homogenizing mixer (18) and its thermal sterilization cells (19) comprises several successive zones and stages, the entire mass of products circulating within these closed cells under advancing pressure ensured by the cylinders of the homogenizer (18) of the order of 60 bar, at a temperature of 180 ° to 220 ° Celsius ensuring sterilization of the products, but also creep and reduction of plastics, without combustion, under ambient charged and saturated with reagents annihilating the stay in the cells is of the order of 20 to 30 minutes depending on the mass admitted and its content.

According to another advantageous characteristic, the thermal cell (20) comprises several successive zones or stages, four in number, the first zone which receives from the mixer (18) and sterilizer (19) the mass of pulverulent and aqueous products, serves as 180 to 220 "Celsius temperature retention chamber, desiccation, evacuation of fumes and vapors by extractor, then vapors, condensed and treated. The second zone or stage ensures stabilization by maintaining the temperature between 180 ° and 220 ° C, the third zone corresponds to the drying of the products, the first and second zones communicating by a rotary airlock (lock) and a venturi, the third zone ensuring cooling. The cell is equipped with transfer thermovis allowing the advance of the product to be treated and a slight depression, for example 3 to 10 mm of CE (30 to 100 Pa), is maintained in the thermal enclosure, by means of a motorized extractor ion with frequency variation. Thanks to the optimization of temperatures, advancement speeds of the material, speed of extraction of air and vapors, thermal stabilization can be regulated without requiring additional air inlets. This regulation is also favored by the principle of heating by thermofluid, thermovis and double jacket. The range of temperatures in the zones of the thermal enclosure (20) generally varies between 180 ° and 220 ° C. At the end of the heat treatment and of the thermal enclosures, one obtains powdery type flour, which is collected on the conveyor (21) ensuring the transfer and the final cooling and which can if necessary, be equipped with densimetric vibrating tables (not shown) to recover the glass particles (cullet) obtained.

While all or part of these pulverulent products are transferred by means of reversing transfer mats (22) then transfer mats (25) and elevation means (26), and silage 527) in storage silos (VI ) and (V), another part or all of the production, depending on the transfer-reversing station (22), is subjected to a pump and spray boom spraying, using binders, for example 2% water-repellent or cements, clay. The product thus bound is sent to an agglomerator (24), manufacture of balls and or blocks, constituted by a hydraulic or mechanical press or the powdery product which has become aqueous is densified and transformed into agglomerates, balls or blocks.

The latter, transported by the stations (25), (26), (27) are then introduced into the storage silos (VI), (V).

All the final products derived and obtained according to the invention, powders, agglomerates, balls or blocks are biologically, sterile, stable, solid, non-evolving, called "inert" and harmless for the environment.

Powdered products do not normally have to be landfilled as they are, they are used as a filler, in the composition of building materials, mixed with cements, silicates, gypsum or clays, they make it possible to manufacture materials more or less dense with good thermal, phonic and mechanical characteristics. Agglomerates or balls or blocks, generally 3 to 10 cm3 in volume, cubic, spherical, oblong or specifically asymmetrical, can be landfilled in class called class 3 (deposition of so-called inert waste) without risk to the environment, either used as water-repellent aggregates for embankments, excavation bottoms or as aggregates and charges for asphalt intended for civil works or in construction and related.

An installation according to the invention, as described, is provided with a control and command unit station, with electronic automata and microprocessors to ensure each and all of the unit tasks and allow the automatic operation of the factory. waste treatment plant, which can be installed near an urban area or in an industrial area.

The unit does not have evacuation systems, neither gaseous nor aqueous, avoiding any pollution of the air, the network, the soil and the subsoils, thus preserving the groundwater. All equipment being dustproof for protection of personnel, equipment and site. The ammonia which can be released during the various reactions in the thermal chambers is emitted in a closed environment, with treatment of the vapors by passage through a soda bath or addition of H 2 O. The process does not consume running water, it feeds on waste, juices and vapors to supply the process and processes the residue of these juices to return them to the internal process network.

It will be noted that in this way, thanks to the process and the associated processing installations in accordance with the invention, it is possible to achieve all of the objectives aimed at, namely: the elimination of the landfilling of household waste in bulk, by the recovery of products from the process, the effective protection of the environment, the reduction of volumes and waste treated, the densification and solidification of these products and their total sterility and stabilization.

And more precisely, compliance with developed and future environmental standards, no combustion, use of apprehensible materials and additives in industry and on almost all of our planet, limitation of energy consumption, footprint reduced, establishment as close as possible to the waste production areas, development of treatment products that can either be admitted to an inert landfill, or usable in embankments, excavation bottom, quarries and charges in the composition of materials.

LEGENDS OF THE ANNEX SCHEDULE

(1) Unloading hoppers

(2) - Transfer extractor conveyor

(3) - Mechanical lacerator bag opener

(4) - Vibrating transfer trough

(5) - Lifting transfer (6) Weight electromagnet

(7) - Mixed transfer, (left. Right)

(8) - Primary shredder

(9) - Lift transfer

(10) - Translator electromagnet (11) - Primary mixer

(12) - Secondary shredder

(13) - Lift transfer

(14) - Secondary mixer (15) - Latency silo mixer

(16) - Tertiary crusher

(17) - Lift transfer

(18) - Hydraulic homogenizer mixer

(19) - Thermal sterilizer

(20) - Thermal stabilizer

(21) - Transfer

(22) - Mixed transfer, (left, right)

(23) - Refiner

(24) - Agglomerator

(25) - Transfer

(26) - Elevator

(27) - Forage harvester

(28) - Thermal generator

I - Lime silo, (CaO)

II - Carbonate silo, (CaCo3)

III - Silicate silicate, clays, cements

IV - Binder silo

V - Silo with agglomerates, balls, blocks

VI - powder silo

- ACM = Additions of mineral fillers

Claims

1. Destruction process neutralization solidification of household waste with a view to obtaining solid, water-repellent, inert and stable end products, leading 5 either a reduction in volumes and landfilling of inert products, or leading to recovery by entering into the composition of materials, a process of the type implementing mixing and homogenization operations with the addition of mineral reagents as well as heat treatment the process being CHARACTERIZED by the combination and scheduling of the following successive stages from the collection, reception of the waste. a) de-bagging of waste by lacerating the bags, then primary steel removal and recovery of ferrous metals; b) primary grinding of desensed waste with recovery of ferrous and non-ferrous non-ferrous materials; C) mixing and homogenization i5 of the ground waste with the addition of first reactants then transfer, d) re-grinding of the waste loaded with reactants then transfer, e) then mixing and kneading with the addition of new reactive fillers then transfer, f) re-grinding then transfer , g) homogenization under hydraulic pressure and further addition of mineral fillers, h) transport of the products under double jacket heating tubes and 0 advancement of the said products by hydraulic thrust, i) then after this sterilization and homogenization operation, j) stabilization and drying under closed thermal enclosures by indirect heating with heat transfer fluid (oils) then transfer into several zones with temperature regulation and optimization systems, separation of fines, and vapors and condensations thereof, k) after transport of the 5 powdery desiccants, at the end of heat treatments, ensification of the final products after impregnation of binders, mechanical, water-repellent, for obtaining balls, blocks and stable (inert) solids, which can be stored and or landfilled in this densified and water-repellent form, or, these final powdered products treated separately, to obtain a charge, allowing recovery to 0 as a component element in the composition of materials. 2. Method according to claim 1, CHARACTERIZED in that the primary and secondary grinding are provided in order to obtain granulometric conditionings of approximately 50mm and 15mm respectively, after a first impregnation, while tertiary grinding after impregnation of the waste leads to a granulometry from 3 to 5mm, before admission to said hydraulic homogenizer. 3. Method according to any one of claims 1 or 2, CHARACTERIZED in that said mineral reagents contain, in addition quicklime and carbonate 0 of sulfates and, or calcium chlorides or other adjuncts by example, natural or synthetic silicates, clays and gypsum. 4. Method according to any one of claims 1 to 3, CHARACTERIZED in that, after said kneading with the second addition of mineral reagents, said impregnated products are allowed to stay. 5. Method according to any one of claims 1 to 4, CHARACTERIZED in that: the addition of said first reagents corresponds to dosages of approximately 10 to 15% (weight) of CaCo3 and 0.5 to 5% of CaO in relation to the weight of the waste; the addition of said second mineral reagents corresponds to approximately 3-10% of CaCo3 and 3-15% of CaO; the third addition of said reagents corresponding to approximately 0.5 to 5% of CaO and 0.5 to 5% of CaCo3 of the weight of the waste admitted to this treatment. 6. Method according to any one of claims 1 to 5, CHARACTERIZED in that the addition of said third mineral reagents is accompanied, if necessary by an addition of water (H20) emanating from the process and, or from station sludge treatment plants. ^ 5 7. Installation for treatment, destruction, neutralization, sterilization and stabilization of household waste according to the method of claims 1 to 6, taken individually or in combination, CHARACTERIZED in that it essentially comprises: at least one hopper (1) receiving bulk waste; means of transfers .o (2,4,5,7); a weight defrailer (6) with ferrous recovery; a primary mill (8) with calibration; after transport on carpet (9); a second undercarriage (10); admission of waste introduced into homogenizing mixers with introduction of reactive mineral charges (ACM); a second mill (12) with recovery of non-ferrous unburnable materials; belt or screw transfer means (13); 5 then the products are admitted into a latency mixer silo (15); and conducted in a tertiary mill (16); vibrating transfer means with screw or belt, leading to a hydraulic homogenizing mixer (18) with new addition of mineral reagents (ACM), a set of thermal chambers and cells, composed of thermal sterilizer (19); thermal stabilizer (20) with several zones, provided with 0 double jacket with circulation of heat transfer fluid (oil) connected to an energy generator (28); a dedusting unit, separation of fines and evacuation of mist, then condensation of mist and decantation (A); means for transferring (21, 22) dehydrated pulverulent products with silage and elevation system (25, 26, 27) for pulverulent products and or treatment of all or part of said pulverulent products by impregnation means of the type mechanical and water-repellent binders (B); press densification means (24) of the impregnated products to obtain balls, blocks; means leading to storage silos (VI, V); series of silos (l, ll, lll) being furthermore provided for the storage of said mineral reagents (ACM) and binders (IV). 0 8. Installation according to claim 7, CHARACTERIZED in that the chambers and thermal cells (19,20) comprise several zones intended successively; the development of exothermic reactions, the creep of plastics, the stabilization of the products on drying, drying and cooling, the advancement of the products being carried out successively by hydraulic thrust and by thermovis (heating screw), under heat transfer fluid in double jacket and under vacuum of the order of 5 to 10 mm of EC ( 50 to 100 Pa), in the said stabilization enclosure.