NL8700588A - Dung-processing - adds solid biodegradable material and separates into filtrate and prim. cake - Google Patents

Abstract

The dung-processing method is partic. for liq. dung, having a separation stage in which solid biologically-degradable material is added to the dung, the mixt. being then separated into filtrate and primary cake. The organic compounds in the filtrate are then biologically and/or chemically broken down in a degrading stage. A dewatering stage extracts water from the filtrate, the concentrated filtrate being then discharged, while the separated cake is burnt in a combustion stage.

Description

ï P HP / AB / Aug-1 - 1 - '

Method and device for processing manure

The present invention relates to a method for processing manure and to an apparatus for processing manure.

The invention particularly focuses on manure processing on such a scale that the entire processing can take place separately on each livestock farm and leads to the formation of liquid that can be discharged on surface water and valuable products to be used for other applications.

The invention is based on the insight that manure can be easily separated into a solid fraction and a liquid fraction by contacting the manure in countercurrent with solid biodegradable material as filter material, in which on the one hand solid parts from the slurry and, on the other hand, adhere colloids and other solutes for physical adsorption and absorption and thus are separated from the filtrate. The primary cake formed containing the biodegradable material is then further dewatered, for example squeezed to increase the dry matter content and then, for example, burned to form fertilizers or optionally sold as fertilizer after pasteurization and / or sterilization. . The filtrate is subjected to a chemical / biodegradation process in which organic compounds are broken down into small organic compounds and in particular mineral substances, after which water is separated from them by freezing, evaporation with vapor recompression and other known means. The aqueous fraction formed can easily be discharged into the surface water, while the concentrated filtrate can be used for various applications in the field of fertilizers.

The method according to the invention is therefore characterized in that it comprises (a) a separation step, in which solid biodegradable material is added to the

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- 2 - slurry and the mixture is then separated in a filtrate and a primary cake; (b) a degradation step, in which organic compounds present in the filtrate are biodegradable and / or chemical; (c) a dewatering step in which water is withdrawn from the filtrate and concentrated filtrate is discharged; and (d) a combustion step in which a separated cake is burned.

Preferably, a conditioning is performed. If the slurry is conditioned, it does not imply that colloid is made easier to separate, the efficiency of the separation step is greater. However, if the primary cake obtained from the separation step is conditioned, then only a smaller volume needs to be processed.

Thermal conditioning can consist of both an increase in temperature and a decrease in temperature, and is intended to disintegrate or denature colloid and protein present. Furthermore, the conditioning may involve a mistake.

Combustible gas, for example methane, may be formed in the degradation or fermentation step. This methane can be burned and the heat supplied can be used internally in other energy-demanding operations, such as in the dewatering step, the combustion step, the conditioning step and the degradation step.

The device according to the invention is characterized in that it comprises a separating unit for adding solid biodegradable material to the slurry and separating it into a filtrate and a primary cake; a degradation unit for the biological and / or chemical degradation of organic compounds present in the filtrate; a dewatering unit for withdrawing water from the filtrate and discharging a concentrated filtrate; and a combustion unit for burning the separated cake. However, it is possible that all or part of the separated cake is re-added to the separation unit, resulting in less solid biological ft? fl pt j &

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i - 3 - degradable material can be used and can be loaded to a higher degree with material to be separated and filtered. The effluent is added back to the separation step.

The separation unit preferably comprises a column provided with an inlet for the solid biodegradable material? an outlet for filtrate? at a level below the biodegradable material inlet into the column slurry inlet? and an outlet for the primary cake, thus the slurry and added solid biodegradable material are in countercurrent, thereby increasing separation efficiency.

Since the slurry inlet is arranged centrally in the column, and an expelling member, for instance a perforated worm, opens into the primary cake outlet, it is avoided that blockages can arise in the column for whatever reason.

The dewatering unit preferably includes a downwardly inclined, cooled surface, cooling means for cooling the surface, a filtrate inlet and an inclined surface outlet for concentrated filtrate and for ice. After the ice layer has obtained a certain thickness, the separation process is interrupted, the ice layer is optionally washed with water and then removed by mechanical or thermal treatment, after which the ice can preferably be used for cooling the cooling medium. Finally, after melting, the ice is discharged diluted with cooling water if necessary.

The conditioning unit preferably comprises a double-walled reactor with a scraping agitator, a slurry supply, a fermentation manure discharge and a gas discharge, the partition wall of which consists of separate chambers.

This makes it possible to compensate for heat loss to the outside, while the temperature in the different shaped segments 35 can be adjusted or changed as desired.

With the aid of the agitator, particles added to the slurry, such as sand and coal particles, will radially pass through a 7 ft.

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\ ~ - 4 - work, with axial displacement remaining small. This promotes the microbial degradation of the substances present in the slurry, because the micro-organisms present on the particles are continuously exposed to a refreshed interface with the manure.

Preferably, the reactor is composed of an acidification reactor and a methane-forming reactor which are fluidly connected to each other. The two reactors are connected in a liquid-communicating manner, while however substantially no particles transfer from the acidification reactor to the methane-forming reactor. The advantage is achieved here that the CO2 and H2S formed during the acidification can be removed and thereby contaminate the CH4 formed in the methane-forming reactor. Furthermore, it can be ensured that the particle concentration in the acidification reactor is lower than in the methane-forming reactor, because the acidification is a faster chemical process and therefore substantially no throughput problems arise. In addition, the reactors can be operated at different temperatures.

Mentioned and other features will now be elucidated on a number of exemplary embodiments of the method and device according to the invention.

In the drawing: Fig. 1 and 2 each show a flow chart of a different method according to the invention for processing manure;

Fig. 3 a separating unit according to the invention; FIG. 4 and 5 each have a different dewatering unit according to the invention; and

Fig. 6 and 7 each have a different conditioning unit in which acidification and methane formation take place simultaneously or separately successively, respectively.

In Fig. 1, slurry 1 is added to a conditioning unit 2, to which a conditioning aid 3 can optionally be supplied. In the conditioning unit

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- 5 - Disintegrated or denatured by colloid (hydrophilic colloid of organic substances, such as proteins and carbohydrates) by heat treatment, making it easier to separate. The conditioned manure 45 is supplied to a separating unit 5 to which solid, biodegradable material 6 is also supplied (this material may consist of straw, peat, wood fiber, broken peanut shells and the like). The biological material 6 functions in a layered construction on the one hand as a filter material and on the other hand as a material to which adsorbed or suspended substances (for instance colloids) dissolved or suspended in the liquid. The conditioned manure 4 passes in countercurrent with the biological material 6 to the separation unit 5 and the filtrate 7 is fed to a decomposition unit 8.

The so-called primary cake 9 formed is fed to another conditioning unit 10, in which, for example, in the case of pasteurization or sterilization, so that the conditioned cake 11 has become germ-free. The germ-free cake 11 is supplied to a pressing unit 12, in which the cake 11 is pressed out to form the secondary cake 13 which can be discharged as such, it can be fed to a combustion unit 14 in which the cake is burned to ashes 15 which have a valuable product to be sold is either to be fed to yet another conditioning unit 16 in which the secondary cake can be pasteurized or sterilized again or for the first time (omitting the conditioning unit 10). It will be appreciated that thermal energy 17 formed at the combustion unit 30 can be used in the heat-demanding conditioning units 2, 8, 16 and / or 23. Furthermore, part of the secondary cake 18 formed in the pressing unit 12 and the effluent can be re-used. are fed to the conditioned manure 4, so that the amount of freshly supplied biological material 6 can be limited and the biological material 6 can be loaded to a maximum degree with substances to be collected therewith.

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In the decomposition unit 8, organic substances present in the filtrate 7 are broken down into small organic substances, preferably even into mineral substances. An aerobic and / or anaerobic microbiological treatment is also carried out on the filtrate in the decomposition unit 8, or a filtration or a chemical oxidation with peroxide or ozone. If necessary, the pH of the filtrate 7 can be adjusted with the aid of the pH unit 19 to a value which is optimal for the process running in the degradation unit 8.

The pretreated filtrate 20 leaving the demolition unit 8 is fed to a dewatering unit 21 in which the filtrate 20 can be dewatered considerably by freeze concentration, evaporation with mechanical vapor recompression or by using, for example, gas hydrates. The water 22 thereby formed can optionally be purified in a water after-treatment unit 23 using chemical oxidation (peroxidation), ozonolysis, filtration on active carbon, on ion exchangers. The purified water 24 can be discharged into the surface water. The concentrated filtrate 25 leaving the water unit 21 forms a salable and more valuable product, or forms a K / N fertilizer.

If necessary, a pre-oxidation can be carried out on the filtrate 20 using the oxidation unit 26.

If combustible gas is produced in the decomposition unit 8, thermal energy obtained from combustion can be used in the dewatering unit 21, whereby the efficiency of the entire process is greatly improved. It will be clear that the products 13, 15 and 25 obtained can optionally be converted into marketable mixed products by mixing.

Pig. 2 shows another variant of the method according to the invention, in which, besides a description of the various treatment steps, relevant process conditions, such as pressures in bar, temperature in ° C and residence times in hours, will also be shown. If relevant 87 0 0 58 8 i * - 7 - mass flows will also be reported.

Slurry 1 (dry matter 2 - 15%, mass flow 250 kg / hour) is fed to a conditioning unit 2 which can optionally consist of a freezing conditioning 2 '(pressure 5 0.8 - 1.2 bar, temperature -10 - -2 ° C, residence time 2-24 hours) or a conditioning with heat in the conditioning unit 2 '(pressure 1-2.5 bar, temperature 50-130 ° C, residence time 1-5 hours). The conditioned manure 4 is supplied to a separation unit 5 described above, which will be discussed in more detail below with reference to Fig. 3. Biological material 6 is supplied and filtrate 7 as well as primary cake 9 leave the separation unit 5. The separation unit 5 operates at a pressure of 0.8-2.5 bar, a temperature of 0-100 ° C and the material has a residence time of 1-25 hours. In the pressing unit 12, the primary cake 9 is pressed into a secondary cake 13 (dry matter 44%, mass flow 46 kg / hour).

The cake 13 can be burned in the combustion unit 14 (pressure 1 - 1.5 bar, temperature 500 - 900 ° C) and 20 delivers ash 15 in an amount of 3.6 kg / hour.

The filtrate 7 is fed to the decomposition unit 8, which in this case contains a mechanical filter in addition to an anaerobic filter. The anaerobic filter consists of a packed column of plastic or mineral support (for example biological material 6 which in that case also functions as a carbon source for the anaerobic micro-organisms). The decomposition unit 8 operates under a pressure of 0.8 - 1.2 bar, a temperature of 10 - 75 ° C and has a residence time of 2-24 hours. The decomposition unit 8 produces 1.9 kg / hour of gas 28 which consists of CH4 and CO2 · The pre-purified filtrate 20 can optionally either pass through the dewatering unit 21 and the after-treatment unit 23 in succession, or first the after-treatment unit 23 and then the dewatering unit 21 In the first case, a freeze concentration is carried out in the dewatering unit 21 at 0.8 - 1.2 bar and at -10 - -2 ° C to yield concentrated filtrate 25 (dry matter 15%, mass flow 20.7 kg / hour) and melted ice (186 kg / hour). Oxidation is then carried out on the melt water 22 8 7 0 0 re 8 i-8 - using 50% H2O2 29 (0.18 kg / h). During the oxidation, 30 CO2 is formed as waste gas. Water emerges from the after-treatment unit 23 in an amount of 186 kg / hour.

Otherwise, the filtrate 20 "is fed to an organic pre-oxidation using 50% H 2 O 2 29 (0.9 kg / h). 0.3 Kg / h CO2 30 evades and oxidized filtrate 31 (20.8 kg / hour, dry matter 15%) is fed to the dewatering unit 21 in which dewatering is carried out by evaporation with vapor recompression (pressure 1.5 - 1.7 bar, temperature 80 - 116 ° C) and the concentrated filtrate 25 has a dry matter content of 15% and represents a mass flow of 20-21 kg / hour Water 24 leaves the dewatering unit 21 'in an amount of 186 kg / hour.

It will be clear that if a mechanical screen unit is used in the separating unit 5, in principle the pressing unit 12 can be dispensed with.

Fig. 3 shows in more detail the separating unit 5. The unit 5 comprises an upright cylindrical column 32 which is provided with an inlet 33 for biological material 6, a slurry inlet 34 for slurry 1 or 4. The inlet 34 connects to a center in the downpipe 35 arranged at the bottom of column 32 but certainly below the level of the inlet 33 and an outlet 36 for filtrate 7. In the lowering tube 35 a drive shaft 38 driven by a motor 37 is furthermore guided, which at the bottom is provided with a worm conveyor 39 which urges loaded biological material 6, now called primary cake 9, to a primary cake outlet 40 and liquid via punches outwards.

The biological material 6 moves downwards through the column in countercurrent to the manure 1, 4, thereby forming a porous filter mass in which solid particles are enclosed and further material is adsorbed or absorbed thereon. Biological material can be fed and discharged continuously or discontinuously depending on the desired degree of loading of the material 6 or the degree of purification of the filtrate 7. Optionally, the inlet 33 can be loaded via 87 0 0 588 - 9 *. 6 which may have been pre-squeezed into the press unit 12.

Fig. 4 shows a dewatering unit 21 comprising a downwardly inclined surface 42 and 43 with coolant 41 cooled and cooled. The surface 42 belongs to the jacket of the dewatering unit and the surface 43 forms part of a distribution tray 44 on which filtrate 20 is brought from a transfer tray 45. Water is removed from the filtrate 20 by depositing it as ice on the surface 43 or the surface 42. After the separated ice has reached a desired layer thickness, if necessary, the ice layer is first rinsed with water 24 (not shown) and then with a scraping agitator 46 driven by a motor 48 and an agitator rod 47, scraped from the surface 42 and leaves the unit 21 as crushed ice or melt water 50 through the outlet 49 If a number of dewatering units 21 are used in parallel, it may be advantageous to pass evaporated coolant along the surfaces 42 and 43 during the removal of the ice, whereby on the one hand the coolant is cooled and on the other hand the ice is melted.

Another dewatering unit 21 is shown in FIG.

5. Conical downwardly thinning cylindrical tubes 51 are suspended above and in a tray 52. The tubes 51 are flowed through with liquid coolant 53 when dewatering or when ice is removed with vaporous coolant. Filtrate 20 is passed over the outer surface 51 via baffles 54 and ice is thereby deposited.

At the bottom of the bin 52, the dehydrated filtrate passes through a screen 55 and leaves the unit 21 as concentrated filtrate 25 via the outlet 56. During the removal of formed ice 50, this dissolves due to the shape of the tubes 51 during the flow with vaporous coolant. , collects on the sieve 55 and is crushed and discharged with a worm conveyor 57. Preferably, during de-icing, the dewatering of filtrate 20 is temporarily interrupted, so that a contact between concentrated filtrate 25 and ice 50 is obtained. Λ ι Γ · / V 'i'; · o - 10 - is avoided.

Pig. 6 shows a conditioning unit 58 in which a fermentation is carried out. A reactor 59 comprises a reactor wall 60 and a thermal insulation 61 between which is divided a space divided into segments 63-65 by partitions 62. Each segment can be supplied with heating air 66.

This air may come from the combustion unit 14 or it may be formed from gas 67 formed during the fermentation. In the reactor 59, a scraping agitator 68 is arranged which can be scraped via the agitator shaft 69 and a motor 70 along the internal surface of the reactor 59. moved and there-. mixes in slurry and generates good particulate / liquid contact in the partially filled reactor 59. Floating and settling layers are thereby avoided and a good contact is established between particles of microorganisms present in the slurry and the raw materials to be converted. Optionally, each segment 63, 64, 65 can be brought to a different temperature, so that an optimal fermentation can be realized.

Cooled air 71 is reheated.

Fig. 7 finally shows another conditioning unit 72 in which slurry 1 is fermented into conditioned manure 4 in two successive reactors 73 and 74. The slurry 1 is thermally heated in a conditioning unit 2 beforehand. In the reactor 73, mainly an acidification takes place and substantially no methane formation. An advantage here is that formed CO2 and H2S can be separated and cannot pollute flammable gas in later form. The final methane formation takes place in the reactor 74. The two reactors 73 and 74 are fluidly connected to each other via the tube 75, however the throughput through the reactors and the volume thereof is such that in the reactor 73 the particle concentration is lower than in the reactor 74, because the acidification reaction proceeds considerably faster. than the methane formation reaction. Furthermore, the throughput of manure for the two reactors is considerably smaller than the radial mixing in each reactor. As in Fig. 6, each segment f *; 7 0 f) Γ, £ f% f - 11 - are individually heated to a desired temperature and the two reactors can also be operated at mutually different temperatures.

The concentrated filtrate finally formed can be worked up into a mineral grain fertilizer, the cake can be worked up into an organic mineral grain mix, while cake and filtrate can be mixed together. The ash can also be worked up into a granular fertilizer, possibly in combination with filtrate and cake.

Because the entire method and device are operated continuously, it will be clear that the amount of material transferred is so small that a compact installation is created that can be used on a livestock farm and the amount of power required is less than the final yield. valuable products and a reduced tax on shaped manure to be removed.

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Claims (15)

A method of processing manure, for example slurry, comprising: (a) a separation step in which solid biodegradable material is added to the slurry and the mixture is then separated into a filtrate and a primary cake; (b) a degradation step, in which organic compounds present in the filtrate are biodegradable and / or chemical; (C) a dewatering step in which water is withdrawn from the filtrate and concentrated filtrate is discharged; and optionally (d) a combustion step in which a separated cake is burned. 2. Method according to claim 1, characterized in that the degradation step comprises an anaerobic and / or aerobic microbiological treatment, an ultrafiltration, an oxidation with a peroxide or ozone. 3. Method according to claim 1 or 2, characterized by a conditioning step, in which the slurry, the primary cake and / or the filtrate is conditioned. Method according to claim 3, characterized in that the conditioning comprises a heat treatment, a fermentation, aeration, a nitrification, a filtration of coarse particles. A method according to any one of the preceding claims, characterized by a pressing step in which the primary cake or the conditioned primary cake is pressed into a secondary cake, which optionally undergoes a conditioning step. Method according to one of the preceding claims, characterized by a water after-treatment step in which a chemical and / or physical purification is carried out on the water from the dewatering step and / or on the filtrate from the decomposition step. Process according to claim 6, characterized in that c% a γ · ·. · .-, v <vc $ - 13 - the water purification comprises a peroxide oxidation, ozonolysis, absorption or adsorption on a carrier such as activated carbon or a ion exchanger. 8. Manure processing apparatus comprising a separating unit for adding solid biodegradable material to the slurry and separating it into a filtrate and a primary cake; a degradation unit for the biological and / or chemical degradation of organic compounds present in the filtrate; 10 a dewatering unit for withdrawing water from the filtrate and discharging a concentrated filtrate; and a combustion unit for burning the separated cake. 9. Device according to claim 8, characterized in that the separation unit comprises a column provided with an inlet for the solid biodegradable material; an outlet for filtrate; at a level below the biodegradable material inlet into the column slurry inlet; and 20 an outlet for the primary cake. 10. Device as claimed in claim 9, characterized in that the slurry inlet is arranged centrally in the column, and an expelling member, for instance a worm, opens into the primary cake outlet. 11. Device as claimed in claims 8-10, characterized in that the dewatering unit comprises a downwardly inclined, cooled surface, cooling means for cooling the surface, a filtrate inlet and an outlet connecting to the inclined surface for concentrated filtrate and for ice . Device according to claim 11, characterized in that the ice outlet is connected to the cooling means. Device according to claims 9-12, characterized by a conditioning unit for slurry, primary cake and / or filtrate. 14. Device according to claim 13, characterized in that the conditioning unit comprises a double-walled reactor with a scraping agitator, a slurry feeder, a ft 7 f; r. r 'r ft P f v'. ·· · v V · 7 - 14 - 'J drain for fermented manure and a gas outlet, where the partition wall consists of separate rooms. 15. Device as claimed in claim 14, characterized in that the reactor is built up of an acidification reactor and a methane-forming reactor which are connected to each other in a liquid-communicating manner. f f, · »r: \ · C .- I ·,:,