PL154803B1 - Method of reclaiming useful gas from garbage by pyrolysis and apparatus therefor - Google Patents

Description

REPUBLIC PATENT DESCRIPTION 154 803 POLAND Additional patent to patent no --- Int. Cl. ⁵ C10B 53/00 B09B 3/00 Reported: 88 08 10 (P. 274155) Priority 87 08 13 Republic Federal Mute ^{0 and} UH OFFICE PATENT Application announced: 89 04 17 RP Patent description published: 1992 03 31

Inventor: Bernd U.

The holder of the patent: PKA Pyrołyse Kraftanlagen GmbH,

Aalen (Federal Republic of Germany)

METHOD OF PRODUCTION OF GAS FROM SEPTTECI BY PYROLYSIS AND EQUIPMENT! TO USE THIS WAY

The subject of the invention is a method of recovering useful gas by pyrolysis, where the finely comminuted waste is brought into the form of fluff, granules or lumps with a size ranging from 1 to 50 mm, and a dry matter content of at least 75 $ and then immediately afterwards at> ^r ° to a heated gasification drum in which effluent gas is produced

The invention also relates to a device for recovering useful gas from garbage by pyrolysis.

Such methods and apparatuses are known from the German insertion description No. 3 347 554 and No. 3 529 445. According to these solutions, the useful gas is recovered very poorly in wastewater, for which it is necessary in particular stages, especially the quantity of w) needed to scrub the decomposition gas pre-treated in the gas corveter is carried out in a closed circuit. However, in order to keep the amount of pollutants in the gas scrubber constant and to ensure the purity of the gas, it was necessary to extract a certain proportion of the water from the closed circuit and replace it with fresh water. The removed water content required additional treatment, because its residual stεmc posed an ecological problem. It also turned out that, due to the varying concentrations of cyanides, phenols and ammonium, direct feeding to the biogas system possibly cooperating with the pyrolysis system was problematic. The fluctuating concentrations resulted in a reduction in microbial growth and, in extreme cases, even the destruction of biocultures. However, the amount of residue that had to be disposed of as special waste by adding chemicals to oxidants and flocculating agents.

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The invention is therefore based on the task of achieving a further reduction of environmentally harmful substances, such as ^{with the} removal of tanto, while maintaining a path-lean method of pre-treatment, with the required efficiency, it is also necessary to achieve at the same time a further increase in the efficiency of the apparatus.

This problem is solved in the context of the invention in such a way that the water bath, through which in? ^r ° is fed from the pyrolysis residue degassing drum, at least a portion of the amount of water withdrawn from the sweep cycle, scrubbing the gas scrubber, is fed.

This way the pyrolysis residue is wetted. It has surprisingly been found that with a sufficient contact time, the pyrolysis residue absorbs an amount of heat that exceeds 140% by weight of its own weight. This means that the rinsing water in a large measure with itself, which may consist of a partial or small amount of those amounts that have been separated from the gas scrubber's closed water circuit. It has been found that this liquid uptake is the greater the greater the carbon content of the pyrolysis residue. Furthermore, a sufficient contact time had to be maintained for complete wetting, o can be achieved, for example, by means of a screw conveyor system with a correspondingly low rotational speed.

In the case of a further refinement of the invention, it can therefore be provided for in the case of a pulverization of carbon content in the pyrolysis residue that inert substances are previously removed from the coal fed to the degassing drum by sorting. This can be achieved with the help of appropriate sorting devices, e.g. sorting machines with comb rollers.

It has, moreover, been shown in a meo-anticipated manner that the pyrolysis residue treated in this way obtains an activated carbon structure with chemically active carbon properties, so that it can be used as activated carbon in other cases.

In a further development of the invention, it can be provided that the pyrolysis residue is fed as an activated carbon filter into a filter device downstream of the gas scrubber tower dryer.

Some sulfur in pure pyrolysis gas which mainly depends on collapse *)! of sulfur in coke, controlled in the gas chamber, are - as in Ladomo - difficult to remove from this gas. If you now install a filter device downstream of the gas scrubber, for example, sulfur or fluorine trucks that have not been completely flushed out may be absorbed by the activated carbon® filter. Since pyrolysis residues are used for this gel, there are no significant additional costs, and the pyrolysis residues can thus even be used sensibly. It also means that the sulfur content of the exhaust gas is significantly below the legal limit values for air at low cost cfmeejscel, thanks to the ozone in the gas convection it is possible to use coke with a slightly higher sulfur content in Bdązek with this, which is a further advantage.

Due to the high absorption capacity of the residual pyrolysis, it is also possible to advantageously obtain the removal of harmful substances from the invasive production processes by adding them to the part of the liquid removed from the closed water circuit. This means that, in addition to its own low-pollutant pretreatment, the method of the invention can also be used for the removal of pollutants from other plants.

It has been found as a further advantage of the process according to the invention that the amount of feedstocks in the pyrolysis gas production plant which is processed in households is more than 50% and per 1 ton of media removed is generally less than 100 1. As a rule, this quantity of waste water is so polluted with harmful substances that it is ecologically undesirable to discharge it in the untreated state. However, a significant and cost-effective reduction of the contamination load can be achieved if it is foreseen, as part of a further fork, that the amount of liquid withdrawn from the water circulation gas purge is thoroughly treated in portions by injecting ozone, so that after this treatment the concentration cyanide does not exceed 10 g / m * and / or phenols - 40 g / m *.

If the pyrolysis residue is subjected to this type of treatment, it can be fed without problems to the biogas systems. Such a pyrolysis residue containing approx

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60% of the liquid, due to the balanced load values of fmolyms and cyanides, due to its high content of carbon and amt, and from gas scrubbing, is a particularly nutrient-rich carrier substance for anaerobic methane generators, which the absorbed, biologically convertible groups of substances transform into useful gas. Ozone-controlled homogenization of the harmful substances ιml.nL reduced the danger of overdosing and thus destroying the biofuel. ^k ®aały in that in order to achieve this effect ujednoradniającego wystaroza ozodaacja short-term, which usually takes Kroo than one ozwwatą ozasu oałkożtej ozoinzacji.

In order to further reduce the pollutant load caused by the indirect waste water, it can be foreseen that the water superimar not bound by pyrolysis residue, which generally corresponds to less than 50% of the part of the water withdrawn from the swept water cycle, is supplied to the gas scrubber. to the system ozoinzaoji additional. This can be done both in parallel and in addition to the use in a biogas system. Aspen by the ozone-toil excess water can reduce the chemical oxygen demand to less than ⁴⁰⁰ mg of oxygen ^per liter Bioče ^h emiozne oxygen demand <Jo OLC. 60 mg / m ^ and contained ^ oy ^jan k ^u f ^ oli ^generally to ^p odżej ^0, 1 g / m \ Because wskuta significant zdążania pulled back from the circuit zα ^ mniętegc water portion of the liquid in the pyrolysis residues should be thus obróboe only wastewater is much poorer, so only a minimal amount of energy is required to cool the remaining amount. In contrast to the known methods, the process according to the slurry therefore has no problem with the disposal of harmful waste.

In addition, it has been found that, as an α1 of the invention, the pyrolysis residue treated according to the process in biogas systems - or in parallel to it - can be used in a lime kiln for energy supply. For this purpose, it is preferable to press it into egg-shaped briquettes. It was found in a surprising way that in the case of initial injection of a part of the substance that is neutral before gasification, its calorific value may approximate the calorific value of brown coal, ^{and that it is} sufficient for the melting process. While maintaining the correct proportions of the components of the mixture, the inert components are calcined or cerumized, with the addition of tactose to thick metals.

Experiments have shown that when properly pressed under glare in the boundaries from 400 to 550 kg / cm to the form of ovoid briquettes and with a product bound from compounds containing calcium, such as lime, filtration dust: y from a lime kiln, in ^^ calcium oxide or calcium hydroxide waste, with a carbonaceous component, such as waste coal dust, as well as substances containing sulfur, chlorine and fluorine and heavy metals, at a temperature of approx. 1200 ° C and for the time of staying in this temperature range, iyi ^{with a} ranging from 45 to 120 m-raut, residual combustion material will repeat, in which almost 100% of the existing total content of chlorine and sulfur as well as meals are subject to aeration or binding with ash almost without modivism. This means that in this way a lycologically advantageous removal of harmful substances and the reduction of heavy metals is achieved.

The only condition for metals is that the molar ratio of one ratio of S10o ₉ ALGO4, CaO, ZnO, PegO4 and / or MgO to the total mole fraction of such metals as lead, chromium, manganese, cadmium, beryllium, barium, selenium, arsenic, vanadium, antimony, bismuth, strontium and / or zircon was pronounced at least 6: 1.

The condition for binding sulfur, chlorine and fluorine compounds is that the molar ratio on the one hand of calcium, magnesium and sodium to the total molar amount of sulfur, chlorine and fluorine in molar is at least 2: 1. The target product pctinili should contain at most 40% by weight, and the calorific value should be equal to 100 kcal / kg, so that fuel elements, e.g. introduced into a lime kiln, can glow with the necessary residence time and temperature, at the same time metals oxidize aia and are taken over to the molten masses of CaO and MsO, where they form neutral cerlm-jziθ complexes. The ceramic compounds are absorbed as sulphites or sulphates, and the liquid chlorine and fluorine are bound into CaClg and CaFg.

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The experiments carried out with the pyrolysis residue have shown that it can take over the function of the palm component in order to raise the temperature. The harmful substances absorbed by it, which may come from sources other than the gas production and pyrolysis plant itself, and which have been added to the water bath for draining the pyrolysis residues, can be removed in a manner favorable to the environment. The pyrolyser therefore leaves no residues which would destroy the final storage.

It was also found that after deducting the own energy demand for the operation of the units, the usable energy remaining at the disposal may increase by over 3% due to the reduction of own electricity demand for the ozonizer for gas purification and thanks to the improved energy use of pyrolysis residues. When the residue of pyrolysis is used in biogas systems, its efkCcc can be increased by using waste substances for heat conversion.

In the method according to the invention, the residues resulting from final disposal are many times smaller than the residue in the case of a refuse incineration plant, which, moreover, are very poisonous 1 mm and must be disposed of as special waste.

The subject of the invention is illustrated in the example of the embodiment in the drawing, which shows the apparatus for recovering the gas used in the schematic diagram.

Since such an apparatus is already known from the basic co-intrusion of the patents mentioned at the beginning, only the parts essential to the invention are described in more detail below. Draining the pyrolysis residues from the degassing drum by means of a plum device is described in German Laid-open No. 3 347 554 (Figs. 7 and 8). Instead of the conveyor shown śliMktwyoh are possible, Scie Clean the other devices of rowiezaeącθ ^p. The only condition is that for an appropriate period of time, an intensive corrosive pyrolysis residue takes place in the water bath.

The waste is fed via a conveyor belt 1 to a primary crusher 2 for coarse grinding. A trough conveyor 3 and a belt conveyor 4 with a magnetic separating device 5 convey the rubbish to the sorting device 6. In the filtering device, the smaller size of the plant is separated and falls into the container below or onto the conveyor belt 7. Likewise, It is also possible to separate the inert substances in order to increase the proportion of carbon in the pyrolysed meteium. The remaining rubbish fraction is fed to the screw thermopress 14 via a further belt conveyor 8, a further shredding device 9 and downstream hydroclon 10, in which heavy parts are separated again via a line 11. Through a line 11 the rubbish and separated rubbish are fed from the tank. 7 on the press ^, edit and βm of the supply 12 to the biogas system 13, in front of which a fluidized bed sorter may be connected, working e.g.

In the screw thermopress 14, a granulate is obtained in the known manner by pressing at a temperature of approx. 110 to 150 ° C, with a rapidly degassing structure and with decoctions from approx. 3,50 mm.

the granulate form can also produce fluff, i.e. the loose form of bits or lumps, revitalized rubbish components pressed into briquettes, having a given size, but usually consumed by long degassing times. The fragmented rubbish components thus fragmented follow the diameter of the airlock 15 with the overhead drum or -ϋ ^, feeding devices, for example feeding slits, to the degassing drum 16, where meltable gasses are produced in a known manner at 450 to 600 ° C. which is fed through a discharge line 17 and a dust separation device 18 to the gas air temperature 19. In the gas generator 19, the effluent gas is pre-treated or transformed into a coal or coke bed. This type of gas is described, for example, in the description of KPN No. 3 317 977

After having passed through the dimensions of ^L > l nliO, 20 gez flows into a gas scrubber, which essentially consists of a water spray tower 21, a blower 22, a purifying cyclone 23, and rdk.τaplajza 24. Purified gas flows through the gas line 25 to the gas meters 26 in which, in the event of an excessive amount of gas being supplied, excess gas can be supplied through a side line 27 to the gas flare 28.

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From the gas meter 26, the gas flows normally to the gas engine 29, which is connected to the generator 30, the burnt exhaust gas being fed to the stack 32 through the exhaust gas line 31.

The gas reactor 19 receives water via line 33 and coke via line 34. Ash and slag are discharged via a discharge line 35. In this case, a return line 36 may additionally be provided for the coke freed from the slag in order to save energy.

A bypass line 37 branches off from the gas line 25 and leads to a gas burner 38 which serves to supply heat to the degassing drum 16. When the unit is started up, the oil burner 39 or a separate gas burner serves to heat the degassing drum. Later, in the course of ongoing operation, the heat requirement for the degassing drum can be completely covered by the burner 38.

The scrubbing water consumed during the gas purification flows into the rinsing water tank 40 and then directly into the filtering device 41 (usually odato cn). The solids, separated in the felting device, are led through the line 42 to the ash container 43. The drain line 44 is drained of the remainder! from the tank 43 »by feeding them back into the degassing drum 16 via a feed device, in this case a sluice 15 with a partition drum.

O ^^ shozon ^ the rinse water from the felting device 41 flows through the return line 45 again to the spray tower 21 of the gas scrubber after passing through the cooling hose 46. Part of the rinsing water connection is fed to the water neutralization device 47 with a scrubber ^^; J, to which the baffles 58 are also led, we will condense the fumes from the plum thermopress 14, unless they are fed through the line 65 to the pre-tank 53 of the biogas system.

From the rinsing water neutralization device 47, this water flows through the return line 78 for the recirculation treatment to the spray tower 21, while a part of it passes through the receiving line 79 to the recirculating water treatment device 48. ] .. ^ of chemical agents that are fed through line 49, as long as the oxidation of these agents is not replaced by ozonization, so that the addition of mood additives can be reduced to increase anti-aging. Through circulation line 50, the water is rinsed partially through the field filter 51 to remove foam, exhaust gases are exhausted through line 52 through chimney 32 and partially fed back to spray tower 21 through line 80.

The water, which has been treated and treated, flows from the circulating water batch treatment device 48 through the line 71 to the pre-tank 53 of the biogas system. If necessary, sludge, sludge, crude oil, etc. can be fed to the inlet tank, if necessary, as indicated by the arrow 54. Condensed vapors can be supplied via line 65 directly to the inlet tank 53, as long as they are not led through the device 48 to the inlet. recirculating water batch treatment.

From the pre-tank 53, the substances treated in the biogas system 13 flow to the hydrolysis stage or to the decomposition device 56. The hydrolysis stage 56 adheres to a heat source 57 by means of a hot water line 62, which branches off from line 62. the cooling unit 46 of the rinsing water treatment unit. In the bottom 67 of the fermentation chamber, the heating system contributes to the temperature increase in the methane area of the fermentation chamber from 33 to 37 ° C. In this way, the excess heat from the pyrolysis system in Co is crystallized in the bio-system 13.

The biogas system 13 is built in the usual way. As a phase-separated biogas system, it may have a normal acid phase in the middle shaft 63 in the upper region, while the acid phase is present in the lower region. The entangled methane gas is drawn off through mettium line 59 and is fed for purification to gas line 25 or to the gas pluose of the pyrolysis system via the intermediate buffer 60 and compressor 61. The fermentation residue is withdrawn via suction line 66 and fed to the feeder pipe 68 by which is brought to the state of approx. 20% dry substance. Solids contained in the fermentation residue can be brought in after 6

154 803 with the average diameter of the drying press 69 to the level of approx. 85% dry substance. The remaining fermentation liquid is collected in space 70 and fed to the treatment device 48 or directly to the sewage network if necessary.

The substances separated in the recycle water batch treatment device 48 can be led through line 64 to the clarifier.

The pyrolysis residues are discharged into the degassing drum 16 via the lift bath 72, which discharging can take place, for example, by means of poppy seed conveyors. The light bath 72 is fed through line 73 to guide a portion of the liquid with the liquid necessary to moisten the pyrolysis residue. The line 73 for guiding the liquid portion branches from the water portion treatment device 48 to the circuits;}.

The pyrolysis residue, thus corroded in this way, is discharged through a line and can, if appropriate, be fed to the biogas system 13 after appropriate treatment, e.g. ozonization or various purification. The biogas system 13 is measured here, of course, by way of example only. For the wjrnlazku itself, it is not necessary. When adding the pyrolysis residues to the biogas system 13, it can also be transferred, if necessary, to the lime-extracting kiln 77 via line 74A.

Likewise, after drying, the residue of the pyrolysis can be fed via line 74B to a filtering device 75 as an activated carbon filter. The filtering device 75 is located between the gas scrubber and the gas meter 26. In this case, however, the activated carbon obtained from pyrolysis residues should, however, be largely free of harmful substances. This is because for this purpose it is done in portions and instead of supplying water through line 73 to lead part of the contaminated circulating water, fresh water is fed to the water bath through line 81 of this water.

If desired, the portion of the liquid taken from the bottom circuit can also be treated in an ozonizer 76. Ozonizer 76 is connected to a device 48 for treating circulating water portions. If a part of the circulating water, taken from the circulation through the intake pipe 79, is properly cleaned in the ozorizer 76 before it is fed to the bath 72 through the pipe 73 for conducting part of the circulating water, then in this case also the pyrolysis residue in the device ΉΙ ^ ηί can be used in this procedure. ^ γπι 75 jeko activated carbon filter.

The function and operation of the kiln 77 for impregnating the lime into which the pyrolysis residue is fed through line 74A is generally known and therefore not further discussed here. Here, the pyrolysis residue is used as fuel together with other fuel components: It is, of course, not necessary for a direct conduit 74A to be led between the water bath 72 and the lime kiln 77. The apparatus according to the invention is so designed that not all devices have to be in the same place. For example, the biogas system 13 and the lime inlet furnace 77 may be located at different locations, and the materials may be transported there in any manner.

The part of the liquid which has not been completely absorbed into the water bath 72 from the pyrolysis residue can also be led through the ozonizer 76, if necessary, for complete ozonization, before it is fed to the clarifier.

It is, of course, not absolutely necessary that the line 73 for guiding the part of the recycle liquid branch from the rinsing water neutralization device 47, as the water can also be withdrawn elsewhere in the circuit, if desired.

Claims (10)

Reservations pltθntiwθ 1. A method of extracting utility gas from garbage by pyrolysis, where the pre-ground dust is brought to the form of fluff, granules or lumps with a size of 1 to 50 mm, and a dry matter liquidity of at least 75%, and immediately thereafter it enters a heated de-aeration drum, where the flow gas is generated and separated from residues such as ash and other constituents, 154 805 and whereby the effluent gas is decomposed in a gas converter® to combustible gas, which is cleaned in a downstream gas scrubber with circulating rinse water, whereby, in order to limit the concentration of pollutants in the circulating water, from the scrubber scrubber water circuit part of the water is withdrawn and replaced with fresh water, and at the end of the pyrolysis residue discharged from the degassing drum is discharged through the water bath, characterized by the fact that at least part of the water that has been taken from the water circuit that rinses the gas scrubbers is fed to the water bath. . 2. The method according to p. A process as claimed in claim 1, characterized in that inert substances are previously separated from the imeol introduced into the degassing drum by sorting in such an amount that the pyrolysis residues discharged from the degassing drum contain at least 255% by weight of carbon. 5. Spoeók »according to claim A process as claimed in claim 1, characterized in that the pyrolysis residue, treated with a portion of the view from the circulation in the washing nozzle, is used as an activated carbon filter. 4. The method according to claim A method as claimed in claim 5, characterized in that the pyrolysis residue as an activated carbon filter is deposited in the filtering device after the gas scrubber. 5. Method according to zaat. 3 · characterized by the fact that ^^ J is rinsed into the circulating water concentrate, taken from the water circuit, by adding comonents of harmful substances from other production processes in order to remove them in order to neutralize them. 6. The method according to p. 5, characterized in that the amount of liquid taken from the water circuit scrubber is treated in the pre portions over ozooUzację, such that ^p of the treatment the concentration of cyanide less than 10 g / m ^ and / or concentration of phenol not ^p rzekracza 40 g / m ^. 7. The method according to p. 5. The method according to claim 5, characterized in that the amount of liquid taken from the water circuit of the gas scrubber, which was not sucked in when wetting the pyrolysis residues, is further ozonized in portions until its αhey. Even though the oxygen demand is less than 400 mg O2 per liter. A method according to claim 1, characterized in that the pyrolysis residue, moistened with a certain amount of sweat, is fed to clarifiers or biogas systems. 9 The water method according to claim The method of claim 1, characterized in that the pyrolysis residue, wetted with a portion of the circulating fluid, is fed to the kilns to spit out the lime. 10. A device for the recovery of useful gas from pyrolysis, with a device for grinding debris, a drying device and a degassing drum with an inlet of pre-comminuted waste, an inlet of pyrolysis residues and a line for the discharge of effluent gas to which a converter is attached gas for recovering decomposition gas, with a gas scrubber downstream of the gas coevert, and with a water bath attached to the inlet of the pyrolysis residues to discharge them, characterized in that from the gas burner device (48) it is led to the water bath ( 72) a line (73) for guiding part of the circulating liquid. 11. The device according to claim 1 A sorting device according to claim 10, characterized in that in front of the degassing drum (16) there is a sorting device for injecting the substance inert oh. 12. Office of water according to claim 10 or 11, characterized in that downstream of the gas scrubber (21, 22, 23, 24) and (47, 48, 49, 50, 51) there is a filtering device (75) in which the pyrolysis residue is inserted as a carbon filter active. The device according to claim 13 A gas scrubber (21, 22, 23, 24) as claimed in claim 10 or 12, characterized in that it comprises an ozonizer (76) for a gas taken from the water circuit of the gas scrubber (21, 22, 23, 24).