DE3042883A1 - Biomass conversion to methane and manure - in two reactors in series with specified different temp. levels - Google Patents

Abstract

Gaseous methane is produced from biomass by circulating it intermittently in a first reactor and by homogenising it, using a heat exchanger for a side stream to heat it to a temp. of 55 deg. C. In a second reactor, the homogenising continues at 35 deg. C, using a pump to recycle a side stream through the heat exchanger to the first rectorreactor, if its temp. should drop below 35 deg. C. This system achieves an optimum conversion of biomass into methane gas and biological manure.

Description

DESCRIPTION

The invention relates to a method for producing methane gas from biomass by introducing a conditioned biomass into a first treatment chamber and a device for carrying out the method.

There are already some methods and devices for extraction of biogas from biomass known, in which a conditioned biomass in a Treatment chamber or reactor is introduced, with simultaneous Gas extraction aims to convert the input material into natural plant fertilizer will.

These goals are, however, of the previously known methods and Devices only reached to a limited extent, be it because of the bi-logical-chemical conditions the metabolic process of the bacteria is not sufficiently taken into account, or be it because the main influence of mechanical-constructional features the optimization of the gas yield per time was overlooked.

Basic research in microbiology over the past few decades led to the result that in every healthy living organism there are several competing components must be present. To prove this was proportionate simple. However, the problem then began with simulating such environmental conditions, that specifically support one of the desired components in their development and thereby eliminating undesired processes at the same time.

Implementation of these findings on a laboratory scale succeeded without major ones Difficulties and proved their correctness.

Transferred to our circumstances up to the large-scale solution means that the optimal generation of energy from biomass is by no means given is if the devices and units required for this are designed in such a way that that this as quickly as possible, excluding any contact with oxygen (in the air) in the airtight fermenter (digestion tower, reactor, chamber etc.) comes. The opposite is the case.

Namely the first phase (from laboratory tests it is known that the microbial degradation of organic substances, i.e. biomass in several consecutive ways and mutually reacting stages takes place) for digestion (cleavage) of the more or less compact hydrocarbon compounds leads to aerobic activity Strains of bacteria, which at the same time produce enzymes that stimulate the metabolism of the anaerobic tribes. For this phase the expression "the acid-forming phase" coined.

However, since it is extraordinarily difficult and expensive, this To scientifically prove processes flawlessly by means of appropriate measurements, we are still in a state of conjecture here.

However, this hypothesis seems to be confirmed by that the results in the gas yield based on the unit of the OTS (organic Substance) of a well-functioning biological sewage treatment plant with connected digestion are twice as high as the results of z. Currently

agricultural biogas plants in the experimental stage. According to the well-known publications by Prof. Dr. Baader, Braunschweig and whose Dr. Dohne, KBTL, Darmstadt, biogas in theory and practice "and Dipl.-Ing.

Perwanger, tandtechnik Weihenstephan, produces what is known as a livestock unit with approx. 500 kg live weight during the day 5 kg TS (dry matter) or converted approx. 3.5 kg OTS (organic dry matter) approx. one cubic meter of biogas, which is in its heat output is roughly equivalent to the heat of combustion of 0.6 l heating oil. On the contrary, the applicant can prove that the same Amount of organic matter after aerobic pre-treatment in the activated sludge tank produces at least twice the amount of biogas.

In the construction of biogas plants, these facts have so far not been used at all considered.

The 3-S two-chamber system therefore tries to use the previously known phases the splitting of high molecular weight hydrocarbon compounds technologically to be implemented in such a way that a universally usable, practicable process is created.

1st phase: In the conditioning pit are supported by mechanical Circulations and crushing with an existing targeted air supply the aerobic Bacterial strains are stimulated to multiply and the associated metabolism activate and perform. This process promotes acid formation and facilitates the decomposition of the high molecular weight hydrocarbon compounds.

2nd phase: The initiated process is carried out in the first chamber heating to 550C continued. However, this chamber is already made airtight, because here the most optimal conditions for the reproduction and metabolism of the Methane bacteria must be given.

3rd phase: The bulk of the methane-producing bacterial strains thrives however, after known laboratory tests at a temperature of 35C below total Air exclusion. In the second chamber these relationships are maintained and thus ensure the most effective conversion of high molecular weight hydrocarbon compounds in methane and organic manure.

According to the invention, solutions and advantages according to the problem are provided by the methods and devices according to claims 1-11 achieved.

The invention is explained with reference to the following FIGS.

Fig. 1 is a schematic cross section through an inventive Device: Fig. 2 is a schematic longitudinal section through the chamber 2 of the invention Device according to FIG. 1; Fig. 3 is a schematic cross-section through the device according to FIG. 2.

The following is the method of the invention and an embodiment of the device according to the invention with reference to the figures n.

The method according to the invention and the device according to the invention are characterized by the fact that essentially the findings described above Applicable in two chambers.

find dung; in the first chamber 1 this is done in a manner known per se conditioned aerobically treated feed product introduced from biomass, by means of a submersible snow pump 3 homogenized and circulated at time intervals and heated by recirculation through a heat exchanger 5 by hot water to 550o. At this temperature, the described acid formation (splitting) takes place in chamber 1 accelerated and already produced biogas through the action of thermophilic methane bacteria, which is withdrawn through a gas line connected to the chamber 1 and stored will.

The feedstock is in a second chamber 2, the actual reactor from chamber 2 kept at a carefully controlled process temperature of 35 ° C, at this temperature the metabolic process of the bacteria in a known manner runs optimally. The control of the maintenance of the temperature takes place in such a way that at Temperaturahfall by cooling a part of the product in chamber 2 through the pump 4 returned to the clamp 2 by the heat exchanger 5 while being heated until the target temperature in the chamber is reached again.

At the same time, through appropriate lines and located therein Slide and valves the product conveyed out of the chamber 2 by the pump 4 be returned through or around the heat exchanger 5 and into the chamber 2, another line then opens into this line through which by means of the Pump 3 over the fresh substrate heated to 55 ° C. in chamber 1 in a defined amount a defined period of time is fed in until the target temperature in the Chamber 2 is set again (so-called by-pass system).

The relevant technical implementation of the regulation through use of temperature sensors, valves and eELn. + r appropriately adapted control electronics is known per se and can easily be carried out by a person skilled in the art.

There is a significant impairment of gas formation in chamber 2 in the formation of a floating layer on the substrate in chamber 2, mainly consists of organic substances that are difficult to digest. Abzuy this floating blanket is in the upper region of the chamber 2 an overflow or drainage channel 7 along at least a part of the inner wall of the chamber 2 is provided, into which the corresponding trained agitator 8, 9 the floating cover continuously or discontinuously out and can be returned to chamber 1 through an overflow.

In the upper area of the chamber 2 an agitator 8, 9 is arranged, continuously or discontinuously, for example by means of an electric motor or can be operated by hand. This agitator is designed so that Form a quiet zone in the lower third or fourth of the volume of the chamber 2 in which the degassed product sinks.

A pipe protrudes into this resting layer through which the degassed Product that, with or without dehydration, has an exceptional drawn Plant fertilizer results, can be deducted.

This pipe is preferably designed as a communicating pipe system, so that when fresh substrate is supplied, roughly the same amount of rotten substrate is deducted.

The agitator has a horizontally mounted shaft 8 0 on which are arranged at 90 and at a certain distance from each other staggered agitator arms 9, these stirring arms forming an angle of 450 with the axis of the stirring shaft 8. This angle has proven to be optimal on the basis of numerous tests, with this angular position simultaneously promotes the floating cover in the drainage channel 7 supported.

These stirring arms 9 are preferably in the form of polygonal or formed round hollow beams into which the substrate enter during the stirring process can. In terms of dimensions, the agitator arms are designed in such a way that they are not deeper Submerge more than two thirds or three quarters of the total depth of chamber 2. In this way, a resting phase can develop in the lower area of chamber 2, which takes up about a third to a quarter of the lower chamber volume.

It is particularly advantageous if the length of the agitator arms 9 is of this type are dimensioned that the vertical distance from the free ends of the agitator arms 9 to the agitator shaft 8 greater than the distance from the agitator shaft 8 to the overflow edge of the Overflow channel 7 is. This is due to the protruding ends of the agitator arms 9 divides the floating layer so that the unimpeded passage of gas results; in addition, the substrate received in the hollow stirring arms 9 exits and is thrown from above onto the floating layer; eventually becomes the floating layer in the direction of the drainage channel 7, which is arranged above the agitator shaft 8, is required.

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Claims (11)

Method and device for the production of methane gas from biomass PATENT CLAIMS 1. Process for the production of methane gas from biomass by introduction a conditioned biomass in a first treatment chamber (1), thereby q e I do not know that the conditioned biomass is in the first chamber (1) is circulated and homogenized at time intervals, while at the same time by passing part of the homogenized biomass through a heating system, insiciondere a heat exchanger (5) the homogenized biomass in the chamber (1) is heated to 550C with formation of methane gas; that in a second chamber (2) the continuation of the metisane gas formation in the homogenized feed from chamber 1 Biomass takes place at 350C, with falling below the target temperature of 350C in the chamber 2 by means of a pump (4) part of the homogenized biomass the chamber (2) passed through the heat exchanger (5) for heating and in the Chamber (2) is returned, at the same time the substrate to be returned current some of the homogenized biomass is extracted from the chamber (2) via the pump (3) the chamber (1) for heating and for transferring fresh substrate from the chamber (1) is mixed into the chamber (2). 2. The method according to claim 1, characterized in that g e k e n n -z e i c h n e t that in the second chamber (2) the floating layer at intervals or continuously withdrawn from a withdrawal pocket and / or channel (7) and returned to the chamber (1) will. 3. The method according to claim 1 and / or 2, characterized in that g e -k e n n z e i c h n e t that in the second chamber (2), sucked on its depth, 2/3 to 3/4 of the upper chamber volume by an agitator (8, 9) continuously or discontinuously with the formation of a resting layer in the lower third or fourth of the volume the chamber (2) is moved. 4. The method according to at least one of the preceding claims, in this way it is not noted that the degassed digested sludge from the rest layer by means of a pipe that dips into this layer when fresh substrate is supplied withdrawn into the upper part of the chamber (2) according to the principle of communicating tubes will. 5. The method according to at least one of the preceding claims, thereby g e k e n n n z e i c-h n e t that in the chambers (1, 2) arranged temperature sensors generate a signal if the temperature in question deviates, which if the temperature is exceeded switches off the pumps (3, 4) above the setpoint and if the value falls below the setpoint adjusts. 6. Device for performing the method according to at least one of claims 1 to 5, g e k e n n z e i c h -n e t by a first chamber (1) with a supply line for conditioned freshening substrate, an immersion cutting pump (3) and its feed line to a heat exchanger (5) and a line connection between the heat exchanger (5) and the chamber (1) to return the heated Fresh substrate and an exhaust pipe for the biogas formed in chamber (1) and a feed line from the chamber (2) to the chamber (1) for transferring the floating layer from the chamber (2) into the chamber (1); and a second chamber (2) for continuous Formation of biogas from the fresh substrate from chamber (1), with a line connection with the pump (3) in chamber (1) passing through the heat exchanger (5) and / or runs around this, and through the fresh substrate through the pump (3) into the Chamber (2) is pumped; another pipe connection from the chamber (2) through the heat exchanger (5) and back into the chamber (2), this Line (6) at the same time the line for transferring the fresh substrate from the chamber (1) can be in chamber (2); a transfer line for transferring the floating layer from chamber (2) to chamber (1), which is the flue pocket and chute (7) in chamber (2) connects to the chamber (1); a drain line for withdrawing the rotten Substrate from the lower third or fourth that is in the resting phase the chamber (2) and a line for drawing off the biogas formed in chamber (2). 7. reaction chamber (2) for the production of methane gas from biomass, e k e k e n n n n z e i c h n e t by a horizontally arranged in the reaction chamber, motor-driven agitator shaft with agitator arms offset by 900, the mounted on the agitator shaft at an angle of 450 to the agitator shaft axis are. 8. Apparatus according to claim 7, characterized in that g-e k e n n -z e i c h n e t that the agitator arms are designed as angular or round hollow tubes. 9. Device according to at least one of the preceding claims, characterized in that in the upper region of the chamber (2) a Overflow or drainage channel or trough (7) is formed with a line for transferring the floating layer from the chamber (2) into the chamber (1) is. 10. Device according to at least one of the preceding claims, in that the shaft (8) of the agitator is in the upper Area below the overflow or drainage channel (7) is arranged, and that the Mixing arms are dimensioned in length so that they are not deeper than up to two thirds to three quarters of the total depth of the chamber (2) extend. 11. Device according to at least one of the preceding claims, in that the agitator arms are dimensioned in such a way in terms of length are that the vertical distance from the free end of the agitator arms (9) to the agitator shaft (8) greater than the distance from the agitator shaft (8) to the overflow edge of the overflow channel (7) is.