SK163799A3 - Method and apparatus for thermolytic treatment of polymer- and cellulose containing materials, especially light shredder residues - Google Patents

Abstract

Thermal processing of shredded plastic articles comprises heating with nitrogen-containing additive/catalyst mixture at to 350 - 600 degrees C in two stages. The gases produced in the first stage of carbonization are used to activate the carbon produced, after which they are burnt to heat the reactors used in the two stages. Method for thermal processing of materials containing polymers and cellulose, especially shredded articles, comprises mixing shredded waste plastic with a nitrogen-containing additive/catalyst mixture in an indirectly heated main reactor (1). Mixing is carried out using a mixing screw (13) while heating to 350 - 600 degrees C, so that carbonized material and gas are produced. The carbonized material is fed to a post-treatment reactor (2) where it is treated at the same temperature with the gas produced, further degassed, activated by the hydrogen in the gases, and fed via a perforated screw to a grinder (3). Here it is ground to the desired particle size, fed to a magnetic separator (9) to remove metal and then molded into active carbon pellets in a pelletizer (11). The gases are fed to a first washer (4), which uses water, and then to a second (5) which uses a calcium-containing solution. The purified gas is heated by heat exchangers (6a, 6b) and burnt in a burner (28) and/or pressure/heat coupling device to heat the main and post-treatment reactors. An Independent claim is included for apparatus for carrying out the above process.

Description

BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for thermolytic treatment of polymers and cellulose-containing materials, in particular pulp waste pulp, and is particularly suitable for utilizing valuable polymers and cellulose-containing residual fractions from sorted mixed plastic wastes from dual waste collection. systems that are commonly known as the "green dot".

BACKGROUND OF THE INVENTION

Packaging materials from industry and households are captured to an ever increasing extent and fed for further processing. In the case of pre-sorted materials from a uniform raw material such as glass or waste paper, their continued use does not normally cause any difficulties. However, mixtures of several substances containing proportions of metals, plastics and paper are problematic. While ferrous metal parts can be relatively easily discarded by magnetic separation, other scrap mixtures of paper, plastics, textiles and metal residues, such as e.g. aluminum foil, greater difficulty. In order to omit a clean storage or storage solution or method, a number of processes have already been proposed which attempt to crush the entire mixture and compress it into the respective moldings or cast parts. Thus, DE OS 3,501,139 describes a method for producing moldings, wherein plastic waste which cannot be reused is recycled. These waste materials are blended, milled and extruded at certain weight ratios and under certain conditions. The relevant conditions are:

ratio of thermoplastics to polyethylene% 15 to 25: 85 to 75; drying is carried out with turbulence;

- the material is softened at 175 to 180 ° C in an extrusion or screw press and compressed into a mold by means of an appropriate nozzle.

If necessary, the corresponding reinforcement (reinforcement) takes place in the extrusion or screw press.

Due to this high proportion of polyethylene, this method gives a narrow range.

DE-OS 2 145 310 proposes the joint grinding of plastic and paper waste. Subsequently, suitable coating of the obtained particles, preferably with cement, is made.

According to DE-OS 2 320 989, domestic waste is mixed with additives or fillers which solidify after the mixing process and are poured into respective containers. Another form of treatment of domestic waste is described in DE OS 2 320 995. Here, waste is treated by mixing it with a colloidal slurry into a plastics material. The colloidal slurry content should be between 10 and 50%. Before processing, the waste is conveyed by an air or wind screen (dust collector), the separated lighter parts are first added to the disintegrating machine and then converted or reshaped into spheres with other parts by splitting or grinding. The resulting plastic mass is allowed to solidify on the respective moldings or cast parts.

In this case, a large proportion of the recoverable substances are lost, since the formation of moldings or cast parts serves only to achieve a closer or more dense packaging (distribution) in the waste dump.

In the currently used waste sorting system from the reuse or recovery system known as the "dual system" or from the paper industry, paper debris, plastics, textiles and metal debris such as e.g. aluminum foil.

Only paper residuals are recovered by physical sorting from these substances or wastes.

These crushed or pulped residual substances are considered as waste and must be disposed of. At the same time, however, methods for the disposal of heat recovery, composting and disposal at public landfills are available for this purpose.

Due to the proportion of water and the large proportion of plastics, combustion is not a problem. In combustion, it represents a large chlorine content, e.g. for foils, PCBs (polychlorinated biphenyls) and possible dioxin formation, environmental problem. In addition, high costs are a disadvantage of such thermal recovery.

Only paper residuals with a paper content of about 80% are composted. A major disadvantage of this method is that even more soil or cleaning sludge must be added in relation to the paper. This results in a very small amount of composted paper. Due to the large proportion of plastics in paper waste, these substances are not compostable and there is no rotting.

Since in many cases there is a possibility of reducing the proportion of cellulose that can be putrefied by chemical treatment and, on the other hand, avoiding unrestricted use of plastic components in the resulting compost, the scope of application of this waste disposal technology is very limited and also uneconomical.

In most cases, waste materials are destined for landfill sites.

Since, on the one hand, the capacity of landfills is limited and, on the other hand, valuable substances are lost from the economy, this method of disposal cannot be a lasting solution either.

In addition, it has already been proposed to mix the waste substances intensively with the olefin mixture, especially the old oil in the ratio of waste to olefin mixture of 5: 1 to 2: 1, preferably 7: 2 to 5: 2, to a homogeneous suspension. 200 ° C to 500 ° C, preferably 250 ° C to 300 ° C and solidify it by cooling.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a simpler method for treating substances containing polymers and cellulose; in particular light substances or scrap from waste pulpers which are suitable for processing, in particular for obtaining cellulose from valuable paper-containing substances, as well as the possibilities of use for the product produced according to this process, the valuable substances contained in substances containing polymers and cellulose, light substances from shredders or pulpers, can be used for further effective recovery or recovery.

This object is achieved according to the invention in that substances containing polymers and cellulose, in particular light substances or pulper shreds, are mixed with nitrogen by-products and / or catalyst mixtures containing metal oxides, according to the method set forth in claims 1 to 6, preferably in a plant which as described in claims 7 and below, are processed to activated carbon and to gypsum containing calcium chloride, the energy content of the process being used in part to maintain the process and partly discharged as mechanical or electrical energy.

Overview of the figures in the drawing

The methods and apparatus will be described in the following with reference to the apparatus shown in FIG.

DETAILED DESCRIPTION OF THE INVENTION

Substances containing polymers and cellulose, in particular light waste or pulp debris, are fed through a material dispenser 14, shaped to act simultaneously as a material passage, to the indirectly heated main reactor 11. By means of a further additive dosing device 15, a mixture of catalyst and nitrogenous additives is fed to the main reactor.

The mixing device rotating in the main reactor 1, in particular the mixing screw 16, serving simultaneously to convey the mixed material, results in the crushed plastic waste and the catalyst mixture in the main reactor 1 being well mixed. By heating to a temperature of 350 to 600 ° C, this mixture is decomposed into a semi-coke and a gas corresponding to the low-temperature carbonization gas. In doing so, the metal oxides cause a mixture of catalysts and additives to accelerate the decomposition of the plastics.

The nitrogen component contained in the catalyst / additive mixture, where urea can be used advantageously in terms of cost, will decompose under the effect of heat on ammonia, water and hydrocarbon.

The resulting semi-coke (which otherwise results from the low-temperature carbonization of coal) is treated with a gas (corresponding to the gas produced by the low-temperature carbonization of coal) in the aftertreatment or treatment boiler 2 at temperatures from 350 to 600 ° C, further degassed and activated by water vapor gas. In this case, the semi-coke is conveyed by means of a perforated conveyor screw to the material emptying space. In doing so, the metal parts contained in the pulverulent substances or shreds are sintered or agglomerated into magnetic particles containing iron and cobalt fractions.

The coke thus produced is ground in a mill 3. Then, the metal components can be separated by means of a magnetic separator 9. The de-metalized coke is compressed by briquetting 11 into active artificial pellets.

The gas produced by the low-temperature carbonization is washed with water in the first scrubbing gas. In this process, a large part of the acid-forming components of the decomposition of the plastics contained in the light parts (shreds) of the waste pulper, especially in the decomposition of PVC, releasing the hydrochloric acid, is neutralized by the ammonia produced by the decomposition of the nitrogen additive. The acid forming components which are not neutralized cause the scrubbing water to leave the first scrubbing gas 6 in a strongly acidic state.

This strongly acidic wash water is used in the mixing tank 21 to dissolve the calcium-containing additive, preferably quicklime.

Here, the calcium additive is used in a weight ratio which exceeds the stoichiometrically required amount by 1.2 to 5 times.

With the thus-formed calcium oxide-containing solution, the gas resulting from the low-temperature carbonization is washed in the second scrubbing gas 5. This removes the remaining acid-forming substances from said gas.

The eluted hydrochloride ions form a crystalline slurry with calcium which is pumped from the second scrubbing gas tank 5 and separated from the water in the solids separator 60, preferably the hydrocyclone. The separated water is then fed to the mixing tank 21.

The solids separated by a known mixed (hybrid) separator from the solution accumulated in the after-scrubbing tank 5 of the low-temperature carbonization gas are dried in an oven or solids dryer 23 by means of the heating jacket waste gases. Then, the water vapor contained in the waste gases is liquefied in the condenser 24 and fed to the pre-scrubbing gas from the low-temperature carbonization.

The purified gas is preheated by heat exchangers 6a and 6b and then combusted in a burner and / or heat-energy coupling device to heat the main reactor 7 and the after-treatment reactor 2. The burner 28 serves mainly for increased heat input in the start-up phase and heat, if the waste heat of the energy-thermal coupling of the motor generator 11 is not sufficient to maintain the process.

The catalyst / additive mixture used consists of amine compounds and metal oxides in a mixing ratio of 5: 1 and 1: 1, the proportion of the amine compounds being controlled according to the actual proportion of PVC in the light waste pulper substances.

The mixture of metal oxides in the catalyst / admixture mixture can advantageously be used separately from the magnetic separator 9, the metal oxides containing components of the semi-coke. Due to the hydrocarbon fraction contained in this component, in this case, it is caused to prevent lumps or pulp debris from occurring in high proportions of plastics in the inlet region of the main reactor K

The apparatus for thermolytic treatment of polymers and cellulose-containing substances for carrying out the process according to the invention can advantageously be adapted according to the following.

The equipment consists of a thermal reaction unit, a flue gas treatment plant and a coal treatment plant.

The thermal reaction unit as the basic core of the apparatus is composed of a mainly cylindrical main reactor 1 and a post-treatment reactor 2. Both reactors are surrounded by a heating mantle 8 '. It is immaterial whether the two reactors are surrounded by one common or always separate heating jacket 8y, which are only connected to one another.

In the main reactor 1 and the post-treatment reactor, a mixing device is arranged in the form of a screw mixer 16 or a conveyor screw 18. These devices are rotated by means of a known drive, which is not shown in FIG. 1, shown about an axis parallel to the axis of the main reactor 1 or aftertreatment reactor 2.

This will ensure that:

• the substances contained in the respective reactor a 2 are well mixed, • an intense heat transfer from the heated reactor liner is guaranteed, and • finally the reagents are transported by said reactors 1 and 2.

For this purpose, in addition to the perforated conveyor worms, rotating vanes are also arranged around the shaft in the respective reactor 1, 2, which can also be combined with perforated intermediate beds.

At the upper end of the main reactor 11 there is a reservoir 12 and a reservoir for additives or additives 13, which in each case are connected to this main reactor via a metering device 14, 15. The metering devices 14, 15 can be designed as known chamber passages.

A preferred solution results when the chamber-lined, piston-sealed piston oscillates in the necessary section between two positions in which the chamber is connected either to the storage tank or to the main reactor 1.

The lower end of the main reactor 1 is connected to the inlet of the post-treatment or finishing 2 reactor.

The finishing reactor 2 opens at the other end to the upper and lower heat exchangers 6a and 6b.

At the upper heat exchanger 6, the flue gas treatment plant is connected to the final treatment reactor 2 by means of the respective piping. This flue gas treatment plant consists of a pre-scrubbing of the low-temperature carbonization gas 5 and an additional scrubbing of the gas.

The pipe connects the outlet of the pre-scrubber of said gas 5 to the inlet of the scrubber of said gas 5. The gas cleaned in the post-scrubbing gas from the low-carbonization is passed through the gas outlet from the outlet of the scrubber 5 through both heat exchangers 6a. and 6b for heating 28 reactors

2. The gas is used first to cool the gas from low-temperature carbonization and coke and then to heat the reactors.

Energy that is not needed in the process can be taken from the process via a thermal-energy coupling as mechanical or electrical energy.

At the outlet of the lower heat exchanger 6b, a coal treatment device 3, 9, 11 is connected via the chamber passage 17.

This coal treatment apparatus 3y 9, 11 comprises a mill 2 connected to the chamber passage 17, a magnetic separator 9 connected to the outlet of the mill 3, which has one outlet for magnetic material MK and a second outlet for non-magnetic material as well as briquetting 11 connected. to this second output for non-magnetic material.

The coke discharged from the chamber passage 17 is finely ground in a mill (milling machine) 3. Thereafter, all the metal components are removed from the coal meal by means of a metal separator 9. The phenomenon that various metal oxides are sintered in heat is used. The iron contained in this sintered metal oxide mixture and possibly the cobalt-derived color pigments ensure that the sintered metal oxide particles can be separated by means of appropriate magnets.

Further, the metal-free coal and oxide-free coal dust can be used either in powder form or compressed by means of said briquetting 11 for activated carbon pellets MK.

While in the pre-scrubbing gas of the low-temperature carbonization gas, the gas is washed with water, an additional or final scrubbing of the gas utilizes 5 liquors containing calcium oxide.

To produce this caustic-containing liquor, it is prepared in a mixing tank 21 which is connected to the metering device 27 so that the material present in the additive tank 26 can be mixed in a predetermined proportion with a portion of the scrubbing water collected in the pre-scrubber tank. and with a liquid phase separated by a solids separator 10 from the sludge collected in the after-scrubbing tank 5 of said gas. The sludge pump 20 connected to the secondary scrubbing gas tank 5 transports the gypsum and calcium chloride containing sludge from said tank 5 to the solids separator 10. This solids separator 10 may advantageously be formed as a hydrocyclone.

The separated liquid is fed to the mixing tank 21 while the solids conveyor is connected to the solids dryer 23. In this dryer 23, the remaining moisture is taken from the sludge, and hot waste gases from the heating jackets 8 of the reactors 1 are led through the CC line. and 2.

The recovered moisture is then recovered by passing the condenser 24 downstream of the solids dryer 23. This recovered moisture can then be used to replenish the scrubbing water in the low temperature carbonization gas scrubber.

Claims (11)

ATTENTION REQUIREMENTS Method for the thermal treatment of polymers and cellulose-containing substances, in particular light substances, waste pulp shavings, characterized in that the shredded plastic waste is mixed in an indirectly heated main reactor (1) with a mixture of catalyst with nitrogen additives, that shredded plastic waste the waste and catalyst mixtures in the main reactor (1) are heated to 350 to 600 ° C using a screw mixer (13) and decomposed into semi-coke and low-temperature carbonization gas so that the semi-coke formed in the after-treatment reactor (finishing) ( 2) gas treated, degassed, activated in the hydrogen contained in said gas (from low-temperature carbonization) and conveyed by a perforated conveyor screw to the chamber material passage that the coke formed is milled in the respective mill (3) to the desired fineness; metal parts separated by a magnetic separator (9) if the deprived oks is pressed in briquetting (11) into activated carbon pellets, That further, the gas produced in this low-temperature distillation or carbonization is washed with water in the first scrubbing gas (4) and in the second scrubbing gas (5) with a calcium oxide-containing solution, That the cleaned gas is preheated by heat exchangers (6a and 6b) and then combusted in a burner (28) and / or a power / heat coupling device (7) to heat the main reactor (1) and the after-treatment or finishing reactor (2). (2) and an additional line connects the pretreatment gas outlet (4) with the additional scrubber inlet (5) as well as that the gas outlet is conducted from the post-scrubber outlet (5) through both at the outlet of the aftertreatment reactor (2) heat exchangers u of heat (6a and 6b) for heating (7, 28) of the reactors (1, 2), as well as that at the outlet of the lower heat exchanger (6b) a coal treatment device (17) is connected via a chamber passage (17). The heat treatment process according to claim 1, characterized in that the calcium oxide-containing solution consists of quicklime which has been dissolved by means of hydrochloric acid, washed out of the flue gases in a pre-scrubbing gas from low-temperature carbonization (4), pre-scrubbing said gas (4). // 2. Heat treatment process according to claim 1 or 2, characterized in that the mixture of catalysts with additives consists of amine compounds and metal oxides in a mixing ratio between 5: 1 and 1: 1. Heat treatment process according to one of the preceding claims, characterized in that in the mixture of catalyst and additives, the metal oxide component of the low-temperature carbonization-containing semicoke, which is captured by the magnetic separator (9), is used as the metal oxide-containing mixture. Heat treatment process according to one of the preceding claims, characterized in that urea is used as the amine compound in the catalyst / additive mixture. Heat treatment method according to one of the preceding claims, characterized in that the solids are separated by means of a known mixed (solid-liquid phase) separator from the solution collected in the final gas scrubbing tank (5) and by the waste gases of the heating shells (5). 8) are dried, such that the water vapor contained in the waste gases then condenses in the respective condenser (24) and is used to operate the pre-scrubbing of the gas (4). Device for the thermal treatment of substances containing polymers and cellulose according to the method of one of the preceding claims, characterized in that it comprises a thermal reaction unit, a flue gas treatment plant and a coal treatment device (3, 9, 11), wherein the thermal reaction unit consists of a predominantly cylindrical main reactor (1) and a post-treatment reactor (2), surrounded by a heating mantle (8), as well as That in the main reactor (1) and the after-treatment reactor (2), a mixing device is arranged in the form of a rotatably mounted mixing screw (16) or a conveying screw (18) so that it is rotatable about an axis parallel to the axis of the main reactor (1). ), or a post-treatment reactor, that at the upper end of the main reactor (1) there are a storage tank (12) through the material feed (14) and an additive tank (13) through the feed device 2 (15) with this main reactor ( 1) connected, That the lower end of the main reactor (1) is connected to the inlet of the aftertreatment reactor (2) and the aftertreatment reactor (2) opens into the upper heat exchanger (6a) and the lower heat exchanger (6b) that the flue gas treatment plant consists of a known pre-scrubbing gas from low-temperature carbonization (4) and a final scrubbing gas (5), l pre-scrubbing of gas (4) via the upper heat exchanger (6a) is connected to a post-treatment reactor * Apparatus according to claim 7, characterized in that the coal treatment device (3, 9, 11) comprises a mill connected to the chamber closure (17), a magnetic separator (9) connected to the mill outlet (3), which it has one magnetic material output (MK) and a second non-magnetic material output as well as briquetting (17) connected to this second magnetic material output. Device according to claim 7 and / or 8, characterized in that the mixing tank (21) is connected to the metering device 2 (27) so that the material present in the additive tank (26) can be mixed in an adjustable ratio with a portion of the scrubbing water collected in the pre-scrubber tank (4) as well as above the solids separator (10) separated by the liquid phase of the sludge collected in the low-temperature carbonization scrubber tank (5) that the mixing tank (21) is connected via a pump leach (22) and, if connected, a spray head with an additional scrubbing head (5). Device according to one of Claims 7 to 9, characterized in that a sludge pump (20) is connected to the gas scrubbing tank (5), the outlet of which is connected to a solids separator (10), the fluid outlet connected to through a mixing tank (21) and the solids discharge is connected to a solids dryer (23) through which the hot exhaust gases from the reactors (1 and 2) are discharged via line (CC), that a condenser (24) is connected with the exhaust air connection of the fabric dryer (23) and from which a condensate pipe is routed to the spray pre-scrubbing head (4). Device according to claim 10, characterized in that the solids separator (10) is designed as a hydrocyclone.