DE102005012936A1 - Acceleration of initial start-up of biogas unit with immobilized methane bacteria, comprises inoculating filling materials with bacteria and immobilizing the bacteria on the filling materials using fermentation gas reactor - Google Patents

Abstract

The time between construction completion and commissioning of a biogas plant, which is equipped with immobilized methane bacteria on packing should be shortened. During operation, tolerable conditions for methane bacteria should be created near the liquid feed.
The inoculation of the packing takes place before the completion of the biogas plant. The biogas plant can be put into operation almost without start-up time.
This is achieved by inoculating the packing of the biogas reactor at or outside the location of the biogas plant prior to its construction completion.
It is an internal backmixing of liquids from the inside of the biogas reactor with the supplied, usually acidic liquid realized by the use of the hydrostatic buoyancy of the mixture of rising biogas and liquid.
According to FIG. 1, a swash plate gas collector is arranged, which opens into an upflow channel ending at the liquid surface. Through him rises a mixture of gas bubbles and liquid and mixes with the incoming liquid. Thus, an internal back and a cross mixing without mechanical installations or supply of energy is achieved.
The method of premature Inoculation of the packing allows the rapid startup of the biogas plant with largely waiving a start-up phase. The self-mixing backmixing increases the productivity of the biogas reactor.

Description

Biogas plants, in particular those for the fermentation solid biogenic substances are often operated in two stages. In the first stage, the hydrolysis takes place, which is the dissolution of all water-soluble Components of biogenic substances and the transformation of many water-insoluble Ingredients in soluble causes. The resulting aqueous liquid contains then such substances, including preferably lower fatty acids, sugars and alcohols used in a biogas reactor as a second stage by the Effect of methane bacteria are converted into biogas.

The Methane bacteria can are free in the reactor, they can be suspended on solid particles or attached to deliberately introduced packings be. The attachment of the methane bacteria to packing - this process is commonly referred to as Immobilization called - has The advantage here is that the Methanbakterien not from the biogas reactor rinsed can be.

at All previously known methods must start the biogas plant done after their structural completion. This startup has among other things, the goal, the necessary amount of microorganisms in the reactors by propagation under optimal conditions receive. It is caused by inoculation, i. through the introduction of microorganisms, preferably methane bacteria, from other plants, supported. The start-up usually takes several months, with the plant no or little biogas produced and thus no economic Advantage from the operation of the plant arises.

Of the The invention defined in claim 1 is based on the problem to shorten the start-up times of a biogas plant, so that the plant as possible Immediately after the completion of the construction work, the design of the biogas according to the design can absorb and thus the economic efficiency of the plant elevated.

This Problem is solved by the features listed in claims 1 and 2 solved.

It It is known that methane bacteria in oxygen-free and moisture-saturated Atmosphere long Time are viable, even if they have no nutrients to disposal stand. This property is exploited according to the invention by the filler already before the construction of the plant either at the site itself, in another plant, at the manufacturer, supplier or Inoculated a third party and the methane bacteria immobilized on the packing become.

Of the The advantage achieved is that the packing immediately for biogas production can be used. The biogas plant can thus immediately after construction Completion of their full operation record and the start-up phase deleted much as possible.

A advantageous embodiment of the invention is in the claims 3 and 4 given. Here, the prefabrication of a complete biogas reactor or even just the filler after done this method. The transport of the thus prepared packing must in airtight containers and in a moisture-saturated the atmosphere respectively.

In a biogas reactor filled with packing and on which the methane bacteria are immobilized, meets the liquid from the hydrolysis stage directly to the first layers of these On filler. Because the liquid from the hydrolysis has a low pH and the methane bacteria under these conditions are not viable or at least in their activity be inhibited, it comes regularly to one reduced biogas production in this reactor section. First with progressive dilution inside the reactor and under the action of methane bacteria the pH in the neutral and thus tolerable for the methane bacteria Area.

Of the The invention defined in claim 5 is based on the problem a mixture of the entering liquid flow from the hydrolysis immediately so with the inside of the reactor liquid to mix that the pH of the resulting mixture in one by the methane bacteria tolerable range (neutral or weak basic), without any installations, such as agitators, or the feeder of energy is necessary.

This Problem is solved by the features listed in claim 5 solved. For this purpose, internals in the biogas reactor are arranged so that the formed and in the liquid ascending biogas collected and passed through a Aufströmkanal becomes. There it mixes intensively with the liquid of the reactor. These Mixture of gas and liquid has due to the higher Gas quantity has a lower density than the surrounding liquid and flows under the effect of the hydrostatic buoyancy by the inflow after above. It is thus a transport of liquid from inside the Achieved biogas reactor to the liquid surface.

Of the achieved with the invention advantage is that a part located in the lower layers or inside the biogas reactor located liquid, their solved has been largely converted from the methane bacteria into methane, according to transported above and with freshly flowing liquid from the hydrolysis mixed and diluted becomes. This will give a tolerable pH even near the inlet and full productivity guaranteed all methane bacteria in the biogas reactor. This backmixing is self-acting and only uses the buoyancy of the resulting biogas in the Liquid. There are no pumps, moving internals or the supply of Energy required.

Two embodiments the invention according to claim 5 will be explained below.

1 shows the schematic cross section through a biogas reactor, which is equipped with packing and with a funnel-shaped, symmetrical gas collector. This opens into a Aufströmkanal, which ends directly at the liquid surface. Above the outlet opening of the outlet channel is the supply for the liquid from the hydrolysis, wherein a distributor ensures the uniform distribution of the inflowing liquid

The Rising bubbles of biogas in the gas collector in the direction passed the Aufströmkanals. There they form with the liquid in the reactor a gas-liquid mixture, whose average density is lower than that of the surrounding liquid. This creates a buoyancy that causes an upward flow. Thus, liquid becomes transported independently from the lower layers of the reactor upwards and with the freshly fed liquid from the hydrolysis which is diluted thereby. Thus come the Methane bacteria now only in contact with liquid whose pH is well tolerated by the methane bacteria. The biogas exits through the corresponding connecting piece and becomes the derived from further use.

2 shows a schematic cross section through a biogas reactor with an asymmetrically arranged inclined blade gas collector. Here an obliquely installed plate is used for gas collection. The gas is directed towards the higher side of the plate and flows into the inflow channel, which ends at the liquid surface. In the vicinity of the outlet opening of the outflow channel is the supply for the liquid from the hydrolysis.

in the Aufströmkanal forms the gas with the liquid a gas-liquid mixture, which flows upwards because of the buoyancy. When exiting the Aufströmkanal is it with the freshly supplied liquid mixed from the hydrolysis. Thus, the ones already described also occur here Effects on. The biogas passes through the corresponding connecting piece and is derived for further use.

Claims (5)

A method for accelerating the commissioning of a preferably two-stage, biogas plant with immobilized methane bacteria, characterized in that the inoculation of packing with methane bacteria - at the same time also called immobilization of methane bacteria on these packing - for use in a biogas reactor in time Commissioning of the entire biogas plant takes place. Method according to claim 1, characterized that the inoculation of packing with Methane bacteria outside location of the biogas plant. Method according to claim 1 and claim 2, characterized in that the biogas reactor together with the so inoculated packing outside the biogas plant is prefabricated. Method according to claim 1 and claim 2, characterized in that inoculated with methane bacteria filling in hermetically sealed containers be transported to the biogas plant. Process for improving biogas production a biogas plant with immobilized methane bacteria thereby in that within a biogas reactor filled with inoculated packings a purposeful backmixing of the liquid contents with freshly supplied liquid carried out by the rising biogas and by constructive activities is supported by the principle of hydrostatic buoyancy, wherein on any moving installations and on the supply of any kind of energy is waived.