DE3326879A1 - Biogas reactor - Google Patents

Abstract

Biogas reactor filled with active biomass, the housing of which is closed at the top by at least one conical or prismatic double funnel. The double funnel is composed of two identically shaped individual funnels nested one inside the other, of which only the outer funnel has a narrow opening at the top, whereas the inner funnel is closed at the top and serves as a gas collection chamber. The intermediate space between the two funnels serves to pass the gases rising from the gas suspension to the next double funnel, at least two double funnels being arranged one above the other at different heights in the reactor housing.

Description

Biogas reactor

The invention relates to a biogas reactor, the housing or more less filled with biomass and at least one conical or prismatic at the top Funnel is complete, the bottom a wide opening for the funnel interior to collect the gases rising from the fermentation suspension and a narrow opening at the top for discharging the collected gases.

Such biogas reactors are already known (see the journal Biotechnology and Bioengineering, Vol. XXII, April 1980, pages 699-734, especially page 701, Fig. 1d and page 729 Fig. 9).

In the area of the fermentation of low-viscosity wastewater, low to medium Concentration (1500 - 20 000 mg / l COD) has been the type of upflow reactor in recent years in which a load of up to 40 kg COD / m3d is processed can. These come especially for the disposal of waste water from the sugar industry Reactors have been increasingly used in recent times, but seem long-term too the application for the direct purification of municipal wastewater in the realm of the possible. The working of the principle of this reactor, enrichment of active biomass due to sedimentation, on the one hand presupposes the existence of sedimenting sludge, on the other hand, the amount of biogas formed as the end product (CH4 and CO2) a certain amount do not exceed, otherwise active biomass is discharged from the reaction system despite the best sedimentation properties. This results in certain limitations for the technical design of the reactor as well as for the substrate concentration: 1.) Since with increasing height of the reactor the -related to the base area of the reactor - the amount of gas produced increases, is the Reactor height limited upwards. To date, reactors are only up to a total height of 6.5 m known (P.M. Heertjes and L.J. Kuijvenhoven 1982, Biotechnology and Bioengineering, Vol. XXIV, 1982, pages 443-459, especially page 444). With very large reaction volumes This restriction requires a large amount of space, especially in the food industry or is not always available in the pharmaceutical industry. Otherwise takes when enlarging the reactors, the surface to be insulated against heat loss compared to compact arrangements stronger.

2.) The fermentation of extremely highly polluted substrates (example whey: BOD = 60,000 mg / l) according to our own experience in conventional upflow reactors only limited possible. The high gas production rates achieved in this way lead to discharge active microbial mass and thus the collapse of sales.

The invention is therefore based on the problem of the disadvantages of this to avoid known biogas reactors.

According to the invention, this object is defined in the claims marked measures solved.

This means that with the help of the subject of the application a) biogas reactors can be created that allow extremely high gas formation rates without a discharge of active biomass is to be feared, b) any height of the biogas reactors possible are.

However, biogas reactors are now also a further state of the art to note that shown and described in the European patent specification 0012476 are. From this a biogas reactor is known, in which an improvement in sedimentation active microbial mass through several one behind the other and one above the other arranged sedimentation spaces is sought. The resulting gas is through ring-shaped Internals directed to the outside and initially in several circular openings that are open at the bottom Gutters, which are arranged one above the other, collected.

The overflowing collecting channels in turn feed the gas into a concentric around the sedimentation spaces arranged gas collection space. The rising gas bubbles Finally arrive at the top of the reactor, from where the gas is fed to a recycling process will.

Compared with the subject of the application, this known one has Biogas reactor, which is already very different in its structure from the subject of the application some major disadvantages: a) Those arranged in each individual sedimentation stage Sludge outlet openings 11 (according to all experimental experience) become clogged tend, because the flow of the suspension to be fermented is not the same as the sludge flow, but rather is directed in the opposite direction.

b) The device is only for the fermentation of low viscosity aqueous Media suitable, since the suspension to be fermented only has a low hydrostatic level Pressure can be promoted through the reactor arrangement. An increase in the hydrostatic Pressure, for example by increasing the delivery rate of the feed pump, leads to The outer annulus overflows directly into the inner sedimentation stage. In this way, the inlet and outlet are directly connected.

c) The overflow of the outer annular space described under b) occurs even with strong gas production, as this increases the specific density of the in it Liquid-gas mixture located decreases and the hydrostatic height increases.

Exemplary embodiments of the invention are shown in the accompanying drawings shown. 1 shows a conical double straightener according to the invention for itself in a biogas reactor housing; 2 shows a funnel design according to the invention with several prism-shaped funnels arranged next to and one above the other; Fig. 3 a biogas reactor housing with 3 conical double funnels arranged one above the other; 4 shows a biogas reactor housing with, for example, 7 conical ones arranged one above the other Double funnels and with several only a few Associated with double funnels Gas discharge lines with throttle valves.

5 shows a biogas reactor housing with the individual double funnels associated floors Fig. 6 a practically tested embodiment of the one shown in l'ig.1 conical double funnel according to the invention arranged in a biogas reactor housing 1 consists of an outer funnel 2 and an inner funnel 3, which are not detailed in The manner shown are fixedly arranged in the cylindrical housing 1, In the Housing 1 contains biomass from which, as a result of fermentation, gas bubbles 5 become free Surface 6 rise above which this biogas rising in the form of bubbles in one upwardly closed gas space 7 of the inner funnel 3 is collected. This Gas space 7 can be rotationally symmetrical as a cone or in the case of larger reactor units as an elongated triangular prism (also arranged in several rows, see Fig. 2) be shaped. The gas space 7 overflows at the edges 8 when it is full; there the overflowing gas is caught by the protruding edges 9 of the outer funnel 2 and in the free space 10 between the two funnels 2 and 3 upwards to the outlet opening 11, forwarded. This way it becomes an overlying low-turbulence space 13 generated with favorable sedimentation conditions.

The gas bubbles rising from an outlet opening (pipe outlet 11) are collected in the gas space of the double funnel above and from forwarded there in a corresponding manner.

However, biomass sludge particles are also carried away with the gas bubbles, However, after the gas bubbles have emerged from the pipe outlet 11 into a through the inner wall of the housing 1 and formed by the outer wall of the outer funnel 2 Space, the sedimentation space 13, sink back and are sedimented there.

The forming in the sedimentation space 13 on excess sludge can flow off at the edges 9 of the outer funnel 2 into the space below.

A clogging of this annular Schlammabf fl ow opening 14 is not to be feared, as the mud movement is caused by a unidirectional flow of the medium to be fermented in the sedimentation space 13 is supported. Those ones The circulating liquid flow is caused by the inside of the double funnel propelled rising gas bubbles.

Close to the gap opening 14 is a on the housing inner wall Guide ring 15 is provided, which prevents the rising gas bubbles from entering the Spaltöffnutng 14 prevents and in the direction of the gas plenum 7 of the associated inner funnel 3 heads.

In the arrangement shown in FIG. 2, they are each off as in FIG an inner funnel closed at the top and one with an outlet opening 18 at the top open outer funnel existing double funnel 16 and prism-shaped housed in a housing 17 to several side by side and at a distance one above the other. As in the figure, exist between the wall of the housing 17 and the outer walls adjacent double funnel and the outer walls of the outer funnel sedimentation rooms 19 and 20, which via stomata 21 and 22 with the overlying spaces in Connected and the sinking of the sedimented mud particles enable. According to the prism design of the double funnel are below the edges of the Outer funnel guide strips 23 and 24 are provided, which hold the rising gas bubbles 25 prevent entry into the stomata 21, 22 and in the direction of the gas plenums 26 of the associated inner funnel.

Another variant of the subject of the application is shown in FIG. Here, for example, in a cylindrical housing 27 spaced apart from one another 3 conical double funnels 28 arranged one above the other. On the lower part of the case 27 a substrate inlet 29 is provided and a substrate outlet on the upper part 30. The resulting gases, e.g.

CH4, CO2, are discharged through an opening 31 in the cover 32 of the housing. Much of the gas created in the sludge bed below is already being used caught by the lowest double funnel directly at the point of origin. The overlying Elements collect gas produced by microorganisms suspended in the fermentation suspension was formed. In this way, the sedimentation spaces 34 create a relatively large low-turbulence area, so that the sedimentation of active biomass and thus the retention capacity of the reactor for microorganisms is significantly opposite the previously usual arrangement improved. This also makes an operation with microorganisms be possible, their sedimentation properties in the conventional "upflow" arrangement would no longer be sufficient.

For relatively highly concentrated substrates (CBS> 30.0O0 mg / l), at the fermentation of which occurs at high gas production rates is an even denser arrangement the gassing elements (high-performance reactor) according to Fig. 4 makes sense.

Each individual element 36 has a certain stirring effect (mammoth pump effect) resulting in a very even supply of the microorganisms involved leads. However, in order to avoid excessively high gas throughputs in the upper parts of the reactor, can produce a certain constant amount of gas (smaller amount of gas than actually generated is) discharged to the outside via a throttle valve 37 each in various stages will. The gas flow through the throttle element can also be regulated. Here the free surface of the liquid is scanned by a liquid level sensor. When the liquid surface rises, the gas flow is reduced so that the liquid surface is regulated at a level so that the inner funnel 48 just stopped overflowing. As in FIG. 3, there is a substrate inlet 38, a substrate outlet 39 and a gas discharge line 40 for e.g. CH4, CO.

In cases where the active sedimentation tendency is high Microorganisms (anaerobic sludge) is to be expected is the introduction of intermediate floors 41 indicated, on which the sludge is held in each individual stage (cf. Fig. 5). The intermediate floors are designed in such a way that gases flow from the bottom to the top and liquids are allowed to pass through, but the sedimenting sludge particles are prevented from passing downwards. This arrangement should also be used for very large construction heights can be useful, as in this case a more even distribution the active sludge can be guaranteed over the reactor height.

A laboratory system is shown as an exemplary embodiment in FIG. That cylindrical housing 49 has an inner diameter of 150 mm. The 5 double funnels are on a continuous tube 42 with a diameter of 20 mm at a distance of 500 mm arranged one above the other. The tube is at the apex height 44 of the inner funnel in the axial direction Direction locked.

The funnel intermediate space 46 leads to radial inlet openings 43 in the pipe. 42. Radial outlet openings 45 in the pipe are located in the area of the gas collecting space 50 of the inner hopper.

The liquid to be fermented is fed into the lowest part of the pipe 51 the distribution takes place via radial openings 52 below a closure 53. The liquid is discharged at 55, the gas leaves the apparatus at the top of the reactor at 56.

Literature Lettinga, G. A.F.M. van Velsen, S.W. Hobma, W. de Zeeuw and A. Klapwijk: Use of the Upflow Sludge Blanket (USB) Reactor Concept for Biological Wastewater Treatment, Especially for Anaerobic Treatment.

Biotechnology and Bioengineering, Vol. XXII (1980), pp. 699/734.

Heertjes P.M. and L.J. Kuijvenhoven: Fluid Flow Pattern in Upflow Reactors for Anaerobic Treatment of Beet Sugar Factory Wastewater.

Biotechnology and Bioengineering, Vol. XXIV (1982), pp. 443/459.

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Claims (12)

Claims g biogas reactor, its housing in whole or in part Filled with active biomass and topped by at least one cone-shaped or prism-shaped The funnel is complete, the bottom a wide opening for the funnel interior to collect the gases rising from the fermentation suspension and a narrow opening at the top for discharging the collected gases, characterized in that a) each The funnel is designed as a double funnel (Fig. 1) in such a way that two of the same shape, but funnels with different dimensions are arranged one inside the other, that a free space (10) between the outer funnel (2) and the inner funnel (3) consists, however, that the inner funnel (3) has no opening at the top and thus forms the gas collecting space (7) for the gases (5) rising from the fermentation suspension, and b) in the housing (1) of the biogas reactor at least two of the aforementioned double funnels are arranged one above the other at a distance (Fig. 2-5). 2.) Biogas reactor according to claim 1, characterized ~ that when using prism-shaped double funnels (16) at least two double funnels next to each other or at least two double funnels are arranged one above the other (Fig. 2). 3.) Biogas reactor according to claim 1 or 2, characterized in that that the edges (9) of the outer funnel (2) opposite those of the inner funnel (3) are preferred so far that when the gas-collecting space (7) is fully filled, over the edges (8) of the inner funnel (3) overflowing gases from the outer funnel (2j are collected and through the space (10) between the two funnels be passed upwards to an open pipe outlet (11). 4.) Biogas reactor according to claims 1 to 3, characterized ~ That the pipe outlet (11) of the outer funnel (2) is designed in such a way that the gases flowing out of it into the gas collecting space of the double funnel arranged above reach. 5.) Biogas reactor according to claims 1 to 4, characterized ~ That the double funnels are carried by a tube (42 in Fig. 6) that extends radially Has openings (43) in the direction and in the axial direction at the apex of each inner funnel (44) is closed, and that at least one opening (45) in the gas collecting space (7) and there is an opening (43) in the funnel gap (10). 6,) Biogas reactor according to patent claims 1 to 5, characterized ~ that through the inner wall of the biogas reactor housing (1) and through the outer wall of each Outer funnel (2) a gas bubble-poor sedimentation space (13) is formed in which the active biomass sludge particles can sediment. 7.) Biog «reactor according to claims 1 to 6, characterized ~ that between the inner wall of the biogas reactor housing (1) and the edge (9) of the Outer funnel (2) such a gap opening (14) is provided that the in the sedimentation space (13) settled sludge particles through this gap opening into the underlying Get to space. 8.) Biogas reactor according to claims 1 to 7, characterized ~ that close below the gap opening (14) on the inner wall of the housing there is a guide ring (15) is provided that the gas bubbles rising from the fermentation suspension (5) on Prevents entry into the gap opening (14) and in the direction of the associated double funnel directs. 9.) Biogas reactor according to claims 1 to 8, characterized ~ that in biogas reactors with several double hoppers arranged one above the other in some of these double funnels in the gas collecting spaces openings (47) of lines are provided that allow the discharge of gas quantities (Fig. 4). 10.) Biogas reactor according to claim 9, characterized ~ that Throttle elements (37) are provided in the lines enabling the discharge of gas quantities are that limit the outflowing gas flow so that it is smaller than that actually amount of gas generated. 11.) Biogas reactor according to claims 1 to 10, characterized ~ that in biogas reactors with several double hoppers arranged one above the other the mutual spacing of the double funnels with a higher volume-related gas formation rate is smaller than with a low gas formation rate (Fig. 4). 12.) Biogas reactor according to claims 1 to 11, characterized ~ that floors (41 in Fig. 5) are provided in the sedimentation rooms, which are suitable for down to the top strömelde Gases and liquids are permeable, however, prevent the sedimented sludge particles from passing downwards.