OA16920A - Process for obtaining energy from organiccontaining waste materials. - Google Patents

Abstract

The invention relates to a process for obtaining energy from organic-containing waste materials (1). For the purpose of storing a carbonaceous product and gaseous energy in a tank (10) and/or direct energy transfer to combined heat and power (11), the organiccontaining waste materials (1) are subjected in precomminuted form to a measurement in order to ensure by possible addition of carbonaceous and/or siliceous material (3) that the ratio of carbonaceous to siliceous material is about 90% to about 10% in the waste materials that are to be further processed, wherein, in addition, the organic-containing waste materials (1) are further comminuted (2) and mixed (4a) with additional materials containing framework silica (3) with advanced comminution (4b) down to the µ range, thereafter compacting (6a) of the comminuted waste material mixture proceeds, heating (6b) of the mixture and separation (6c) of the same, whereupon the gaseous materials obtained in further course are fed to a tank (10) and/or to combined heat and power (11), while the solids obtained pass through a separation (12) of siliceous from carbonaceous materials and the carbonaceous materials obtained are stored as end product (13).

Description

Process for obtaining energy from organic-containing waste materials

The présent invention relates to a process for energy recovety from organicscontaining waste materials.

The technological background includes US 5,087,375, AT 389 474 B,

CH 688 990 A5, and DE 33 29 771 Al. US 5,087,375 describes a method for treating hazardous and toxic wastes which comprise organic substances and metals for the purpose of producîng insoluble industrial raw material, where the waste materials are mixed with polymeric material comprising inorganic compounds which form stable compounds with the metals, moldings are formed from the plastics mixture obtained, and are heat-treated in order to remove the plastics material, and the inorganic substances remaining are bound by calcining and sintering to form stable, insoluble complex compounds.

AT 389 474 B discloses the use of fine minerai, silicatic/carbonatic fractions for the ordered déposition ofultrafine and/or pasty waste materials, the fine minerai fractions enveloping or infilirating the waste materials and forming a matrix.

CH 688 990 A5 relates to the reprocessing of organic and/or inorganic residues from old, reconstructed landfills and/or fresh garbage to form a material which can be re-used, with élimination of pollutants.

The above-identified DE 33 29 771 Al the binding ofpollutants in the production of briquettes made from organic products or from waste products, where inorganic compounds are added for the chemical binding of pollutants in a compressionmol ding operation and/or on pyrolysis/incineration.

DE 10 2007 006 137 Al discloses a hybrid product comprising organic and inorganic partîculate materials and/or mixtures of materials, which together form a substantially homogeneous matrix. With the aid of an additive (auxiliary), the possible properties of an end product are calculable beforehand, and this additive leads to the formation of crysta! structures with a high spécifie internai surface area, and it meets a variety of goal-oriented functions, such as, for example, energy media or substances for energy conversion, porosity-generating agents, structuring agents, reducing agents and/or filter material.

The goal pursued by the invention is that of providing a process for energy recovery from organics-containing waste materials, by which a carbonaceous product is supplied in solid, liquid, and gaseous form to a tank for storage and/or directly to a combined heat and power process for driving.

This goal is achieved in accordance wîth the invention in that

a) the organics-containing waste materials in pre-comminuted form are subjected to a measurement for identifying the constituents and also to détermination of the ratio of the fraction of carbonaceous material to the fraction of silîcatic material, in order to ensure, by admîxing

- carbonaceous and/or silîcatic material where appropriate, that the ratio ofcarbonaceous to silîcatic material is about 90% to about 10% in the waste materials for further processing,

b) as the process continues, there is ongoing measurement of the fractions of carbonaceous material and silîcatic material,

c) the organics-containing waste materials are further comminuted and mîxed with additional tectosilîcate-containing materials, with continued comminution down into the μ range,

d) compacting ofthe comminuted waste material mixture is carried out, with addition ofphyllosîlicates, heating ofthe mixture, and séparation thereof into individua! solid, liquid, and gaseous phases under reduced pressure, after which the solids which remain arc mîxed with furtheradded phyllosîlicates and are pclletîzcd,

c) the pellets produced are subjected to pyrolysis, and

f) the gaseous substances obtained in this procedure are supplied to a tank and/or to a combined heat and power process, while the solids recovered undergo séparation of silîcatic from carbonaceous materials, with the carbonaceous materials recovered therefrom being stored as end product

The advantage ofthe présent invention lies, by comparison with conventional processes, in that wastes currently lackîng any or lacking great recyclability can be reprocessed in an energy recovery system to give hîgh-value products such as m étals, silicates, and carbon and/or carbon compounds.

The % figures for fractions of constituents or components hereinafter are in each case % by weight, calculated relative to dry matter, unless otherwise specified.

“Organics-containing waste materials encompass, for example, domestic garbage, industrial garbage, sewage sludge, recovered paper materials, and the like, 40 comprising whatever kind of organic material and/or biological residuals, such as, for example, paper, wood, textiles, plastics, etc. The fraction of organic materials in the individual waste materials that can be employed is 70 - 90% in the case of domcstic garbage with 6000 - 12 000 U/kg dry matter, 50 - 90% in the case of industrial garbage with 15 000 - 36 000 kJ/kg dry matter, 80 - 95% in the case of sewage sludge with 1000 - 5000 kJ/kg dry matter, and 75 - 95% in the case of recovered paper materials with 2000 - 8000 kJ/kg dry matter, the requirement being for at least 40% of organic materials.

Examples of “silicate-contaîning materials” with which the waste materials are mixed are tectosilicates, silicatic minerais, such as a wîde variety of granitic rocks, for example, vulcanîtes, silica sand, construction mbble, and the like.

The invention is elucidated in more detail below with reference to fig. 1, which shows a flow diagram in accordance with the invention for a process for energy recovery.

The organics-containing waste materials 1 which serve as input energy are precommînuted and subjected to a measurement of the constîtuents for the purpose of identifying the constîtuents, and also to a détermination ofthe ratio of the fraction of carbonaceous material to the fraction of silicatic material. The nature of the waste materials used as starting material is to be such that the ratio of carbonaceous to silicatic material therein is about 90% to about 10%. If values deviating from this ratio are found, then carbonaceous and/or silicatic material must be added until the carbonaceous and silicatic materials in the waste materials for further processing are présent in the 9:1 ratio. It should be noted hère that the individual components of the materials used are subject to ongoing measurement 5 throughout the process. The pretreated organics-containing waste materials 1 are digested or further comminuted 2. Thereafter, in a continued commïnution step, a greater fineness, preferably down into the μ range, Îs achieved, with addition and mixing 4a of tectosilicates and/or finely ground silicatic minerais 3 as additives.

The additives, and also, for example, construction rubble, hâve a greater degree of hardness than the waste materials, and hence act as abrasives, thus producing, on further commïnution 4b, a finely divided hybrid product of organic and inorganic substances, which at the same time arc fiberized by means of refîner grinding. The additives, which advantageously may also be fine silicatic substances from a blast fumace, are used with a component size of 0,001 to 3 mm, wîth the fraction of substances wîth a component size of below 50 pm being approximately 40%.

As a resuit of further fine grinding, the individual pièces of the respective composition of substances are reduced to a size of less than or equal to 50 pm. The fraction of substances with a 3 mm fine-particle sîze. Le., with a diameter of more than 3 mm, is around 5%, and the fraction of substances with a 1 mm fine-particle sîze is around 8%; the rcmaînder has a fine-particle sîze with a diameter of below 1 mm, the principal fraction possessîng a sîze of less than 100 pm. This fineparticle distribution ratio îs relevant for the stabilization of the mixture or of the framework construction.

In the course ofthe ongoing monitoring ofthe process, there is measurement ofthe composition and identification ofthe individual components 5 ofthe comminuted or ground mixture produced, by means of powder diffractogram, in order to allow targeted compacting 6a, heating 6b, and subséquent séparation 6c of the individual components în the subséquent process step. In this case, essentially, a variety of measurements are carried out, yielding the following data:

- the fineness of grinding,

- the distribution index,

- the weight,

- the moîsture,

- the pH.

The elemental composition ofthe raw material prepared îs determined continuously by means of X-ray fluorescence analysis (XFA), with a détermination in particular of the carbon content

These captured data enter a computer processing unit where they are compared with functionally dépendent or physically dépendent values, thereby enabling, in a targeted manner, the compacting 6a, heating 6b, and subséquent séparation 6c of the individual components; in this context, if they are not already présent in the silicatic material, it is necessary to add adjuvants composed of phyllosilicates 7a, such as clay with at least 50% iron. Preference is given here to using iron-rich phyllosilicates, or phyllosilicates containing ïron-like cations, preferably from the group of malle phyllosilîcate minerais, such as chlorites, smectites, îllite, biotite, and the like. The compacting 6a here is dépendent on the moîsture, the température, the CO₂ content, and the phyllosilîcate fraction, where CO₂ formed serves presently as compression medium.

The mixture of waste materials is compacted 6a under pressure în a preliminary chamber, the preliminary chamber further comprising a (hydro)cyclone-type chamber in which, by heating 6b, there is a séparation 6c of metals (heavy metals), silicates, and carbonaceous materials according to spécifie weight, melting point, and conductivity. In other words, there is a séparation 6c analogous to that in a centrifuge: a rotational movement causes outward movement of the particles formed in the course of the heating 6b · in which the cations introduced via the mafic phyllosilîcates, such as iron or iron-like cations, are oxidîzed with réduction of COj - and also particles containing such oxidized cations, thereby producing a mechanical séparation into individual solid. liquid. and gaseous phases by means 5 of centrifugal force. This occurs in dcpendence on the materials, typically at 40°C to 850°C, with the materials présent under reduced pressure in the (hydro)cyclonetype chamber. The liquid phase consists predominantly of liquefied organic material (plastics material). It should be borne in mind here that among the particles of material having a spécifie weight (densîty) of < 0.09 N/m³ (weight force per unit volume), a residual silicate fraction remains of 1.4% to 1.7%, but not more than 5%. The resulting gaseous phase is supplied directly to a tank 10 and/or to a combined heat and power process 11.

As a resuit of the compacting 6a of the mixture under its own moisture content, the 15 partie le size of the mixture, made up of waste materials and added sîlicatîc material, is fashioned in such a way that the interstices between the compacted particles ensure supply of heat The size of the particles and their density therefore détermine the reduction/oxidation process and the reaction time. The ratio by volume of compacted material to interstices in the framework-/skeleton-like solid 20 material produccd as a resuit of the added phyllosilicates is generally about 2:3.

The mode of functîoning of the (hydro)cyclone-type chamber for the séparation of the individual components of the compacted material is substantially analogous to that of a centrifuge. Sînce the particles move outward in the chamber, there is a classifÿing of the particles according to spécifie weight Depending on the respective spécifie weight, the particles entrained by a stream of material emerge at precisely defined émergence points in the marginal area ofthe chamber, resulting în a précisé séparation of the individual components. The carrier for this stream of material is usually enriched CO₂ gas, in order to minimize the heat loss during the operation,

The séparation 6c of the entire mass of the raw material produced takes place in the absence of air, by removal of air with a vacuum pump via the spécifie weight, which conveys the material into closed silos, with séparation into a pure carbonaceous component and a pure silicate component

In the transition from the preliminary chamber to a main chamber, the solids are admixed and hence mixed 8a with finely divided phyllosilicates 7b, examples being clay(s) and/or clay-mineral material as bindeifs), the mass of solids in tum 40 being intended to attain or hâve a carbonaceous material content of about 90% and a silicatic material content of about 10%, in order for pellets to be produced by pelletizîng 8b. The finely particulate phy llosilicates 7b are, for example, clay minerais or materials rich in clay minerais, such as kaolin, montmorillonite, or bentonite, for example. These phyllosi 1 icates 7b hâve a binder effect only in the moîst state, preferably at a moisture content of about 15% to 25%. ln addition, the phyIlosilicates 7b support the séparation of the individual components.

The objective ofthe pelletizîng 8b is to ensure the conveyability ofthe solids, for which purpose the solids are required to hâve precisely defined particle size, particle content, and moisture.

In the main chamber, the materials mixture, présent in the form of pellets, îs subjected to pyrolysis 9 in general at 600°C to 800°C, there also being a phase séparation and hence a splitting of the gaseous and solid substances, as a resuit of 15 their different densities, in the absence of air.

The séparation takes place generally by means of a (hydro)cyclone, which receives the operational material supplîed from the reactor via a vacuum pump. The vehides used for the quantitative flow are preferably CO₂ gases, which ensure a 20 high energy balance. With this process, the energy is not blown into the chimney and lost, but instead is utilized in a process-efiïcîent way. A further advantage is that the carbon compounds in the gas mixture give up energy via a heat exchanger, în a targeted way, and are therefore utilized directly. In principle there are further possibilîties for séparation, such as a shaker table or up-current classifier, although 25 ail ofthe séparation possibilîties mustalways take place in the absence ofair.

The separated gaseous and solids substances are thereafter subjected to separate further processing. The gaseous substances which remain are supplîed to the tank 10 or to the combined heat and power process 11, while the solids which 30 remain are separated 12, with utilization of different densities, into silicatlc material and carbonaceous material; the silîcatic material can be retumed to the first process stage, that ofthe mixing 4a and commînuting 4b ofthe waste materials 1, and the carbonaceous fraction is stored as product 13 or supplîed directly to the combined heat and power process 11.

The remaining residue forms a reusable siiicatic binder, which can be retumed and utilized as tectosilicate for the commînuting 4b ofthe organics-containing waste materials 1.

In other embodiments of the invention, different individual process steps can be omitted and in part replaced by comparable steps, without aflectîng the fondamental objective of energy recovery.

The subject matter of the présent invention ïs elucidated in more detail by means of the examples below.

Example I

A light fraction from an auto shredder, comprising the organics-containing material obtained in the shredding ofold automobiles, following magnetic removal of métal particles, is mixed in pre-comminuted form, in an amount of 92%, with sands, clays, and lime residues in an amount totaling S%, based in each case on the weight of the dry mass, and this mixture is commînuted. With continued mixing and further comminution, the particles of the mixture are digested down into the μ range; ongoing measurement ascertains the fractions of carbonaceous material and silicatic material. In dependence on the ratio of the fractions that is ascertained, tectosilicates, in the présent instance pumice, are admixed, with continued comminution and with fiberization of the organics-containing material in a refîner 20 operation, so that the ratio of carbonaceous material to silicatic material is approxlmately 9:1.

This pre-processed mixture material is compacted in a prelîminary chamber with addition of about 20% of mafïc, ultrafïnely divided phyllosilicate, in the présent 25 instance chlorite, based on the total silicate fraction, with formation of a cake which remains porous, and this compacted cake is progressively heated to about 500°C in the absence of air. This causes the cake to fall apart, and there is séparation into the individual aggregate states in a cyclone-type chamber. The gas phase, and also the liquid phase formed from liquefied organic material (plastics), 30 are stored in tanks, for their further utilization. The solids which remain are admixed with further phyllosîlicates, in the présent instance montmorillonite, and these components are mixed and pelletized. The pellets formed, whose silicate fractions amount to approximately 2.8%, are subsequently subjected to pyrolysis under anaérobie conditions at around 53O°C. In this pyrolysis, the pellets, constructed of framework-/skeleton-like material, fall apart into fine particles, with a séparation again into gas, liquid, and solid phases. The separated silicatic material îs recycled as raw material into the System, for renewed use. The carbonaceous materials are stored for energy recovery or supplied directly to a combined heat and power process.

Example 2

Organic domcstic garbage (plastic, leathcr, etc.) in precomminuted form, in an amount of about 85%, is mixed and comminuted with construction rubble (gypsum 5 plastcrboard panels, etc.) in an amount of about 15%, based on the weight ofthe dry mass, and this comminuted mixture is further subjected essentially to the process régime as per example 1, with the exception of the conditions and parameters specified hereinafter:

î) In the présent instance, the tectosilicate used, which îs added in the refîner operation, is perlite.

ii) Chlorite as mafic phyllosilicate is added, in the présent instance, in an amount of about 15%, based on the overall silicate fraction.

iii) Following removal of gas phase and liquid phase, the solids which remain are admixed with kaolin as a further phyllosilicate.

iv) The pellets hâve a silicate fraction of about 1.9%.

îiv) The pyrolysis takes place at a température of about 61 O^eC.

Example 3

Paper sludge, in an amount of about 78%, is mixed and comminuted with recovered paper materials with a silicate fraction of about 40%, which makes up about 10% based on the overall mass, in an amount of about 22%, based in each case on the weight of the dry mass, and this comminuted mixture is further subjected essentially to the process régime as per example I, with the exception of the conditions and parameters specified hereinafter:

î) In the présent instance, the tectosilicate used, which is added in the refîner operation, is finely ground granîtic minerai.

ii) Bîotite as mafic phyllosilîcate is added, in the présent instance, in an amount of about 17%, based on the overall silicate fraction.

iii) Following removal of gas phase and liquid phase, the solids which remain are admixed with bentonite as a further phyllosilîcate.

iv) The pellets hâve a silicate fraction of about 2.4%.

iiv) The pyrolysis takes place at a température of about 585°C.

Claims (5)

1. Claims:

   1. A process for energy recovery from organics-containing waste materials (1), characterized in that

   a) the organics-containing waste materials (1) in pre-comminuted form are subjected to a measurement for identifying the constituents and also to détermination of the ratio of the fraction of carbonaceous material to the fraction of silicatic material, in order to ensure, by admixing carbonaceous and/or silicatic material (3) where appropriate, that the ratio of carbonaceous to silicatic material is about 90% to about 10% in the waste materials for further processing,

   b) as the process continues, there is ongoing measurement of the fractions (5) of carbonaceous material and silicatic material,

   c) the organics-containing waste materials (1) are further comminuted (2) and mixed (4a) with additional tectosilicate-containîng materials (3), with continued comminution (4b) down into the μ range,

   d) compacting (6a) of the comminuted waste material mixture is carried out, with addition of phyllosilicates (7a), heating (6b) of the mixture, and séparation (6c) thereof into individual solid, liquid, and gaseous phases under reduced pressure, after which the solids which remain are mixed (8a) with further-added phyllosilicates (7b) and are pelletized (8b),

   e) the pellets produced are subjected to pyrolysis (9), and

   f) the gaseous substances obtained in this procedure are supplied to a tank(10)and/orto acombinedheat andpower process(11), while the solids recovered undergo séparation (12) of silicatic from carbonaceous materials, with the carbonaceous materials recovered therefrom being stored as end product (13).
2. 2. The process of claim 1, characterized in that the individual components (5) are measured by means of powder diflractogram.
3. 3. The process of claim 1, characterized in that the silicate-containing materials obtained when separating (12) the silicatic material from the carbonaceous material are retumed to stage a).
4. 4. The process of claim 1, characterized in that the gaseous substances obtained by the séparation (6c) in stage d), optionally together with the gaseous substances obtained in stage c), are supplied to the tank (10) and/or to the combined heat and power process (11).

   «
5. 5. The process of claim 1, characterized in that the séparation (6c) in stage d) of the solid, liquid, and gaseous substances takes place by way of a rotational movement.