DE102010017027B3 - Method for operating man-made and/or biogenic methane-containing gas generating system e.g. biogas system, in natural gas network, involves supplying gas flow to heating system, and storing electrical energy generated in system in supply - Google Patents

Abstract

The method involves generating raw combustion gas in a methane-containing gas generating system, and executing primary cleaning of the generated combustion gas by using substance e.g. ferric hydroxide. Precision cleaning of large portions of the combustion gas is executed, and the gas is supplied to a supply unit (11). The gas is odorized in the supply unit, and combustion gas flow with desired calorific value is produced for a block heating system (4). The gas flow is supplied to the heating system, and electrical energy generated in the heating system is stored in a mains supply (5). An independent claim is also included for a distributed system comprising a man-made and/or biogenic methane-containing gas generating system.

Description

The present invention relates to a method for operating plants for the production of anthropogenic and / or biogenic, methane-containing gases in the natural gas network as well as a composite system to be used for this purpose. In particular, it should be made possible by the method to make a supply of consumers with a constant fuel gas quality, taking into account a changing calorific value of the raw gas.

The plants for the production of anthropogenic and / or biogenic, methane-containing gases include in particular biogas plants, sewage treatment plants and landfill gas plants. In these, depending on the starting materials used, a more or less methane-containing gas is generated, which can be used after appropriate treatment as CO ₂ -neutral fuel for heat and energy.

In biogas plants, an anaerobic fermentation of organic substances produces a raw biogas that is similar in nature to natural gas. The essential difference to the latter is generally the higher CO ₂ content. Depending on the fermentation temperature and the substrate used, methane levels in the biogas of approx. 40 to 75% are achieved. In addition, biogas still contains water, nitrogen, oxygen, hydrogen sulfide and several other trace components. Since the calorific value of the gas in the first gas depends primarily on the methane content, one of the most essential and also the most costly workup steps of the raw biogas is the methane enrichment by removal of CO ₂ .

In further processing steps, which serve the gas composition, the corrosive or otherwise harmful to the following equipment constituents are removed from the raw biogas or at least minimized their content. In particular, these are water, hydrogen sulphide and, if appropriate, siloxanes which can be introduced via the substrates (for example body-care product residues in sewage sludge). If the fermentation does not take place under complete exclusion of air, the oxygen and nitrogen content of the biogas can also be critical as they contribute to a reduction in the calorific value.

For the sewage gases and landfill gas, the above considerations apply analogously. Differences arise primarily in the composition of the raw gases produced. Therefore, the present invention will be explained in more detail below only with reference to the biogas. The statements made here are applicable to the other anthropogenic and / or biogenic, methane-containing gases, in particular sewage gas and landfill gas.

The customary in the prior art use of biogas in projects from agriculture is such that the mostly small biogas plants are operated directly where the substrate used is present. Thus, either biogenic residues or renewable resources can be processed profitably. In this process, the raw biogas produced is converted directly into a combined heat and power plant and the generated electricity is fed into the power grid.

The decisive disadvantage here is that the heat generated during power generation can usually only be used for the fermenter heating, as in the often sparsely populated rural areas no large heat release z. B. to households or industrial companies is possible. Much of the heat - about 80 to 90% - has to be released into the atmosphere. That is, the cogeneration plant is powered by electricity. The only advantage is the fact that it can do without the rather expensive technology of gas treatment.

In order to make biogas utilization more efficient, the state of the art also pursues the approach of preparing the biogas for natural gas quality so that it can then be fed into the natural gas grid. The most important treatment steps here are, as mentioned above, drying, desulphurisation and methane enrichment by removing CO ₂ .

In 1 the method is shown schematically. In a fermenter ( 1 ) raw biogas is produced, which is used in raw biogas processing ( 2 ) is brought to natural gas quality. Since the power generation of the treated biogas does not take place in the vicinity of the biogas plant, the heat requirement of the fermentation must be either via a small combined heat and power plant to supply its own needs ( 3 ) or via an electric heater ( 7 ), which are connected to the electricity grid ( 5 ) is generated locally. For this purpose, the treated biogas stream is fed into a cogeneration plant for the supply of heat users ( 4 ), a partial flow taken. In the cogeneration plant for the supply of heat users ( 4 ) generated electrical energy is in the power grid ( 5 ) and the heat generated by the heat users ( 6 ) made available.

The decisive advantage of this method is that the biogas in the existing natural gas network can be transported to where there is a sufficiently large heat demand. There, the biogas can be converted into electricity in a combined heat and power plant using the heat generated become. Thus, the operation of the cogeneration plant is heat-controlled. Thus, electricity is generated only when the heat can be given to corresponding consumers. It is also possible not to use the entire amount of biogas in a single cogeneration plant, but to divide them into several combined heat and power plants to ensure complete heat loss.

The disadvantage of this method, however, that the biogas treatment is very complicated and expensive. In particular, the methane enrichment represents a significant cost factor. In all this common techniques in addition to the required consumables or equipment also additional process steps such as the compression of the raw biogas to the operating pressure of the purification step necessary.

Based on these known methods, it was the object of the present invention to provide an improved method for the operation of plants for the production of anthropogenic and / or biogenic, methane-containing gases and a composite system of facilities therefor, which has the advantages of a decentralized use of the processed Combine fuel gas with the lower cost of direct untreated power generation. In addition, the improved process should also allow increased flexibility in the use of the fuel gas.

• – Erzeugung von Rohbrenngas in mindestens einer der Anlagen;
• – Grobreinigung des erzeugten Rohbrenngases;
• – Feinreinigung des größeren Teils des erzeugten grobgereinigten Rohbrenngases;
• – Zuführung dieses Gasstroms in eine Einspeisungseinheit, wobei die Einspeisungseinheit eine Gasdruckregelanlage enthält, von der aus das mindestens eine Blockheizkraftwerk beschickt wird und die mit dem Erdgasnetz verbunden ist;
• – Odorierung des Gasstroms in der Einspeisungseinheit;
• – Herstellen eines Brenngasstroms mit einem gewünschten Brennwert für das mindestens eine Blockheizkraftwerk, wobei der Brennwert gemessen wird und zum Herstellen des gewünschten Brennwertes eine Brennwertkompensation derart erfolgt, dass in der Einspeisungseinheit in Abhängigkeit des gemessenen Brennwertes des odorierten Gasstroms der mindestens einen Anlage zur Erzeugung von anthropogenen und/oder biogenen, methanhaltigen Gasen entweder bei Unterproduktion dem odorierten Gasstrom Erdgas aus dem Erdgasnetz beigemischt wird oder bei Überproduktion der überschüssige Anteil des odorierten Gasstroms in das Erdgasnetz eingespeist wird, wobei die Zumischung des Erdgases und die Einspeisung in das Erdgasnetz in einer Gasdruckregelanlage erfolgt;
• – Zuführen des resultierenden Brenngasstroms in das mindestens eine Blockheizkraftwerk, das mindestens einem Wärmenutzer Wärme liefert, wobei der Abstand zwischen der Einspeisungseinheit und den Blockheizkraftwerken jeweils größer ist als der Abstand zwischen den Blockheizkraftwerken und den jeweiligen Wärmenutzern;
• – Einspeisung der in dem mindestens einen Blockheizkraftwerk erzeugten elektrischen Energie in das Stromnetz.

The object is achieved by the inventive method for operating plants for the production of anthropogenic and / or biogenic, methane-containing gases in a network with combined heat and power plants in a natural gas network and heat users, with different gas qualities for self-supply as the first area and smaller part and for Combined heat and power plants arise as the second area and larger part, wherein at least one of the combined heat and power plants supplies heat to at least one of the heat users and generates electrical energy for a power grid, including the steps

• - production of raw fuel gas in at least one of the plants;
• - Rough cleaning of the raw gas produced;
• - Fine cleaning of the larger part of the coarse-cleaned raw combustion gas produced;
• - Supplying this gas stream in a feed unit, wherein the feed unit includes a gas pressure regulating system, from which the at least one cogeneration plant is charged and which is connected to the natural gas network;
• - odorization of the gas stream in the feed unit;
• Producing a fuel gas stream with a desired calorific value for the at least one cogeneration plant, wherein the calorific value is measured and for producing the desired calorific value, a calorific value compensation takes place such that in the feed unit depending on the measured calorific value of the odorized gas stream of at least one plant for the production of anthropogenic and / or biogenic, methane-containing gases is mixed either in underproduction the odorized gas stream natural gas from the natural gas network or overproduction of the excess proportion of the odorized gas stream is fed into the natural gas network, wherein the admixing of the natural gas and the feed into the natural gas network takes place in a gas pressure control system;
• - Supplying the resulting fuel gas stream in the at least one combined heat and power plant that supplies heat to at least one heat user, wherein the distance between the feed unit and the combined heat and power plants is greater than the distance between the combined heat and power plants and the respective heat users;
• - Infeed of electricity generated in the at least one combined heat and power plant in the power grid.

The plants for producing anthropogenic and / or biogenic, methane-containing gases are preferably biogas plants and / or landfill gas plants and / or sewage treatment plants. Particularly preferably, the plants for producing anthropogenic and / or biogenic, methane-containing gases comprise at least one biogas plant and after the coarse purification, the gas stream is divided into a smaller volume flow which is fed to at least one combined heat and power plant which supplies the at least one biogas plant with heat. and a larger volume flow, which is fed to the fine cleaning.

In 2 the process of the invention is shown schematically using the example of a biogas plant. Solid lines in the figure symbolize gas flows, dashed lines heat flows and dotted lines electric currents. The raw biogas is produced in at least one biogas plant ( 8th ) and then undergoes a rough cleaning ( 9 ). From the coarsely cleaned biogas stream, a smaller part is branched off, into the cogeneration plant to supply its own needs ( 3 ) and there for the at least one biogas plant ( 8th ) produced heat required. The generated electrical energy is in the power grid ( 5 ) fed. The greater part of the roughly purified biogas stream flows into the fine cleaning ( 10 ) and from there into the feed-in unit ( 11 ). This is where the odorization of biogas takes place. To deal with the heat users ( 6 ) to provide agreed calorific value, then takes a measurement of the calorific value of odorized biogas. The feed unit ( 11 ) also has a gas mixing device and is connected to the natural gas network ( 12 ) connected. Depending on the measured calorific value, it either mixes the odorized natural gas gas stream from the natural gas grid if it is underproduced ( 12 ) or, in the case of overproduction, feeds the excess portion of the odorized gas stream into the natural gas grid ( 12 ) one. The resulting fuel gas stream is then at least one combined heat and power plant for the supply of heat users ( 4 ), the at least one heat user ( 6 ) Supplies heat, fed. The combined heat and power plants for the supply of heat users ( 4 ) are close to the heat user ( 6 ), which they each provide. At least the distance between the feed unit ( 11 ) and the combined heat and power plants to supply heat users ( 4 ) is in each case greater than the distance between the combined heat and power plants for the supply of heat users ( 4 ) and the respective heat users ( 6 ). The heat generated in the at least one cogeneration plant for the supply of heat users ( 4 ) accumulating electrical energy is also in the power grid ( 5 ) fed.

For billing with the heat users ( 6 ), the determined calorific value of the supplied fuel gas which is used in the feed-in unit ( 11 ) and not - as usual - the flow rate.

This makes it possible to dispense with a part of the treatment steps. The cleaning operations on the raw biogas can be carried out according to the respective requirements. This results in different gas qualities for the individual process stages. The first area is the self-supply of the biogas plant with heat from a first group of combined heat and power plants. Here, a coarse purification of the raw gas with respect to moisture and sulfur and optionally silicon-containing compounds, in particular siloxanes, is sufficient. The second area comprises the combined heat and power plants, which provide the heat users with heat. Since these are no longer located in the direct biogas plant area, an additional fine cleaning on the necessary for feeding into the natural gas network sulfur and moisture values and odorization of the biogas is required here.

Optionally, in the case of coarse purification, even a slight enrichment of methane can be carried out. However, this does not need to be led to natural gas quality, since a too low calorific value of the fuel gas can be compensated by mixing with natural gas from the grid. This measure is particularly advantageous if the CO ₂ removal at the same time a reduction of moisture and sulfur content can be achieved. Thus, two major advantages are achieved: By far the most costly process step of methane enrichment can be minimized by the calorific value compensation by means of natural gas or completely eliminated, while ensuring that the customer receives its guaranteed calorific value, even at peak load times.

In 3 the feed concept according to the invention is again shown schematically in the example of a biogas plant in its four main sections. The figure shows which measurements are necessary in the course of the process in order to control the process control and to ensure a compliant feed-in and billing.

The section of raw biogas production contains the biogas plant ( 8th ) with the measuring devices for the volume flow ( 18 ) and the gas composition ( 19 ). The measurement of the gas composition serves to monitor the fermentation process. Particularly important characteristic values of the composition at this point are the moisture content and the hydrogen sulphide content of the biogas. A measurement of the main components such as methane and CO ₂ can also be carried out. If the values for methane and CO _{2 are} outside tolerable values, the takeover of the gas from the fermenter would have to be stopped because the gas would then be unsuitable for feeding.

The section of the preparation contains the gas storage ( 13 ), drying ( 14 ), the desulphurisation ( 15 ) and the blower ( 16 ). This section contains temperature measuring devices in several places to ensure process quality ( 20 ) and the pressure ( 21 ).

In the biogas feed-in section, the main component of the feed-in unit ( 11 ) the gas pressure regulating system ( 17 ) and the natural gas grid ( 12 ) contain. The measuring devices include measuring devices for the volume flow ( 18 ), the gas composition ( 19 ) and the calorific value ( 22 ). In the gas pressure regulating system ( 17 ) the odorization of biogas takes place. Likewise, in the case of a natural gas supply, a perfect mixing of the two gases is ensured. The measurements of the calorific value and the gas volume flow required by the DVGW regulations are carried out before and in the gas pressure regulating system ( 17 ) carried out. The measurement of the gas composition serves to ensure the correct treatment of the gas.

Finally, the section Utilization contains the combined heat and power plant for the supply of heat users ( 4 ), in front of the measuring equipment for the volume flow ( 18 ) and the calorific value ( 22 ) are arranged. Before use, it comes again because of the temporary mixing of biogas with natural gas to a volumetric and calorimetric measurement so that the amount of energy consumed by the consumer for billing can be correctly recorded.

In a preferred embodiment of the invention, the coarse purification of the raw biogas produced includes coarse desulphurisation and / or drying.

Particularly preferably, coarse desulphurization is already carried out in the at least one biogas plant. It is advantageous if the coarse desulphurization takes place chemically by adding sulfur-binding substances. As sulfur-binding substances are particularly suitable iron compounds, in particular iron (III) hydroxide.

Preferably, the coarse purification of the raw biogas produced additionally includes methane enrichment by means of membrane diffusion. This method allows at relatively low cost, a methane enrichment to economically maximally meaningful 70 vol .-%.

The fine cleaning preferably includes a fine desulfurization and / or drying and / or removal of silicon-containing compounds, in particular siloxanes. The fine desulfurization is carried out particularly preferably to a residual content of hydrogen sulfide of not more than 5 mg / m ³ . The drying is preferably carried out in the coarse purification to a dew point temperature of 0 to 10 ° C, preferably 2 to 8 ° C, more preferably 4 to 6 ° C and in the fine cleaning to a dew point temperature of -30 to 0 ° C, preferably -25 to -5 ° C, more preferably -20 to -10 ° C.

In a further preferred embodiment of the method according to the invention a gas storage is connected upstream as a buffer tank to ensure a uniform Rohbiogasversorgung the rough cleaning.

The fuel gas stream supplied to the at least one combined heat and power plant from the feed unit preferably has a calorific value of between 6 and 12 kWh / m ³ .

• – mindestens eine Anlage zur Erzeugung von anthropogenen und/oder biogenen, methanhaltigen Gasen mit einer Grobreinigungseinheit verbunden ist,
• – sich an die Grobreinigungseinheit Mittel zum Aufteilen des die Grobreinigungseinheit verlassenden Gasstromes in einen kleineren Volumenstrom und einen größeren Volumenstrom anschließen,
• – der größere Volumenstrom in eine Feinreinigungseinheit eingeleitet wird,
• – der gereinigte Gasstrom anschließend in eine Einspeisungseinheit eingeleitet wird,
• – die Einspeisungseinheit eine Vorrichtung zur Odorierung des Gasstroms, Mittel zum Messen des Brennwertes des odorierten Gasstroms und mit dem Erdgasnetz verbundene Mittel zum Mischen und Dosieren von Gasen enthält,
• – die Einspeisungseinheit mit mindestens einem der Blockheizkraftwerke verbunden ist, das mindestens einem Wärmenutzer Wärme liefert, wobei der Abstand zwischen der Einspeisungseinheit und den Blockheizkraftwerken jeweils größer ist als der Abstand zwischen den Blockheizkraftwerken und den jeweiligen Wärmenutzern, und
• – die Blockheizkraftwerke zur Einspeisung der erzeugten elektrischen Energie mit dem Stromnetz verbunden sind.

The object of the present invention is further achieved by a composite system of plants for the production of anthropogenic and / or biogenic, methane-containing gases and combined heat and power plants for operation on a natural gas network and to heat users for carrying out the above method, in which

• At least one plant for producing anthropogenic and / or biogenic, methane-containing gases is connected to a coarse purification unit,
• Connecting to the coarse cleaning unit means for dividing the gas stream leaving the coarse cleaning unit into a smaller volume flow and a larger volume flow,
• - the larger volume flow is introduced into a fine cleaning unit,
• - The purified gas stream is then introduced into a feed unit,
• The feed unit contains a device for odorization of the gas stream, means for measuring the calorific value of the odorized gas stream and means for mixing and metering gases connected to the natural gas network,
• - The feed unit is connected to at least one of the combined heat and power plants, which supplies heat to at least one heat user, wherein the distance between the feed unit and the combined heat and power plants is greater than the distance between the combined heat and power plants and the respective heat users, and
• - The combined heat and power plants are connected to feed the generated electrical energy to the power grid.

Most preferably, the plants for the production of anthropogenic and / or biogenic, methane-containing gases are biogas plants and / or landfill gas plants and / or sewage treatment plants. If the plants for generating anthropogenic and / or biogenic, methane-containing gases comprise at least one biogas plant, the divided smaller volumetric flow of coarse-cleaned raw combustion gas is supplied to at least one cogeneration plant which supplies the at least one biogas plant with heat.

Particularly preferably, the coarse cleaning unit includes devices for coarse desulphurisation and / or drying of the raw biogas. The coarse cleaning unit preferably further includes a device for membrane diffusion.

The fine cleaning unit of the composite system preferably includes devices for fine desulfurization, for drying and / or removal of silicon-containing compounds, in particular siloxanes. In a particularly preferred embodiment of the composite system, the device for fine desulfurization comprises at least two reactors charged with potassium iodide impregnated activated carbon, which can be operated alternately. They are designed so that the remaining reactors can handle the entire volume flow when switching off one of the reactors. This makes it possible to exchange the activated carbon of a container that is saturated with sulfur and needs to be renewed, and still feed biogas continuously. Of great advantage is the significantly higher loading capacity of the activated carbon for sulfur by impregnation with potassium iodide. Thus, at relatively low process temperatures of 50 to 70 ° CH ₂ S contents below 5 mg / m ^{3 are} possible.

4 shows an embodiment of the method according to the invention. This is intended to illustrate only the preferred use of the components and is not to be construed as limiting. The measuring and control technology for controlling the valves and their interconnection with each other are not included in the drawing.

Coarse desulphurisation already takes place in the fermenter ( 1 ) of the biogas plant. For this purpose, the biomass are also added iron salts during the filling of the fermenter. The fermenter ( 1 ) is equipped with a safety valve, the pressure relief in the torch ( 26 ). Similarly, via a valve, an excess pressure from the gas storage ( 13 ), which is placed on the fermenter ( 1 ) and the raw biogas buffers in the torch ( 26 ) escape.

From the gas storage ( 13 ) the raw biogas is passed through a heat exchanger ( 23 ), which is connected to a cooler, not shown. The cooled gas stream then passes into the dryer ( 14 ). The water separated here is transferred to the fermenter ( 1 ) returned. Following the dryer ( 14 ), the optional diversion of a small part of the coarse-cleaned biogas stream takes place as fuel gas for a combined heat and power plant to supply its own needs ( 3 ), which the heat supply of the fermenter ( 1 ) is not used (for reasons of clarity) 4 shown).

Via another heat exchanger ( 23 ), which is traversed in the cross-flow of the fine desulfurized hot gas stream, the preheated biogas in one of the two desulphurisation reactors ( 24 ) guided. The finely purified biogas is then removed from the blower ( 16 ) and as required via the above-mentioned heat exchanger ( 23 ) or a bypass with radiator ( 25 ).

In the gas pressure regulating system ( 17 ) then the odorization of the biogas, pressure adjustment and the admixture of natural gas or the injection of surpluses in the natural gas network. From the gas pressure regulator ( 17 ), the combined heat and power plant will be supplied to heat users ( 4 ) is fed with biogas, which the heat user ( 6 ) provides the needed heat. The electricity generated is fed into the grid (not shown in the drawing).

The gas pressure regulating system ( 17 ) has a direct-acting gas pressure regulator for natural gas or biogas with integrated safety shut-off valve and upstream filter in addition to the odorizing system. The regulation of the operating pressure of the lines represents the priority use of biogas as fuel gas for the combined heat and power plant for the supply of heat users ( 4 ) for sure. In a typical configuration, for example, a pressure of 500 mbar for the safety shut-off valves is set for both strands, whereby the operating pressure in the natural gas train is regulated to 170 mbar and in the biogas train to 200 mbar. The regulation for calorific value adjustment then takes place as a function of the measured calorific value of the odorized biogas train.

LIST OF REFERENCE NUMBERS

1

fermenter

2

Rohbiogasaufbereitung

3

Combined heat and power plant to supply its own needs

4

Combined heat and power plant for the supply of heat users

5

power grid

6

heat users

7

Electric heating

8th

biogas plant

9

coarse cleaning

10

fine cleaning

11

supply unit

12

natural gas network

13

gas storage

14

desiccation

15

desulphurization

16

fan

17

Gas pressure control system

18

Measuring device volume flow

19

Measuring device gas composition

20

Measuring device temperature

21

Measuring device pressure

22

Measuring device calorific value

23

heat exchangers

24

Feinentschwefelungsreaktor

25

cooler

26

torch

27

Siloxanentfernungsreaktor

Claims (20)

Method for operating plants for the production of anthropogenic and / or biogenic, methane-containing gases in a network with combined heat and power plants in a natural gas network and heat users, with different gas qualities for self-supply as a first area and smaller part and for cogeneration plants as second area and larger part, wherein at least one of the combined heat and power plants supplies heat to at least one of the heat users and generates electrical energy for a power grid, including the steps of - generating raw fuel gas in at least one of the plants; - Rough cleaning of the raw gas produced; - Fine cleaning of the larger part of the coarse-cleaned raw combustion gas produced; - Supplying this gas stream in a feed unit, wherein the feed unit includes a gas pressure regulating system, from which the at least one cogeneration plant is charged and which is connected to the natural gas network; - odorization of the gas stream in the feed unit; Producing a fuel gas stream with a desired calorific value for the at least one cogeneration plant, wherein the calorific value is measured and for producing the desired calorific value, a calorific value compensation takes place such that in the feed unit depending on the measured calorific value of the odorized gas stream of at least one plant for the production of anthropogenic and / or biogenic, methane-containing gases is mixed either in underproduction the odorized gas stream natural gas from the natural gas network or overproduction of the excess proportion of the odorized gas stream is fed into the natural gas network, wherein the admixing of the natural gas and the feed into the natural gas network takes place in a gas pressure control system; - Supplying the resulting fuel gas stream in the at least one combined heat and power plant that supplies heat to at least one heat user, wherein the distance between the feed unit and the combined heat and power plants is greater than the distance between the combined heat and power plants and the respective heat users; - Infeed of electricity generated in the at least one combined heat and power plant in the power grid. A method according to claim 1, characterized in that it is the plants for the production of anthropogenic and / or biogenic, methane-containing gases to biogas plants and / or landfill gas and / or wastewater treatment plants. A method according to claim 1 and 2, characterized in that the plants for the production of anthropogenic and / or biogenic, methane-containing gases comprise at least one biogas plant and after the rough cleaning, a division of the gas flow into a smaller volume flow, the at least one cogeneration plant, the at least one Biogas plant supplied with heat, is supplied, and a larger volume flow, which is fed to the fine cleaning, takes place. Method according to one of claims 1 to 3, characterized in that the coarse purification of the Rohbrennbiogases generated includes coarse desulphurisation and / or drying. Method according to one of claims 1 to 4, characterized in that a coarse desulphurization is already carried out in the at least one biogas plant. Method according to one of claims 4 and 5, characterized in that the coarse desulfurization is carried out by chemical means by the addition of sulfur-binding substances. A method according to claim 6, characterized in that the sulfur-binding substances are iron compounds, in particular iron (III) hydroxide. Method according to one of claims 1 to 7, characterized in that the coarse purification of the Rohbrennbiogases produced additionally includes a methane enrichment by means of membrane diffusion. Method according to one of claims 1 to 8, characterized in that the fine cleaning a fine desulfurization and / or drying and / or removal of silicon-containing compounds, in particular siloxanes, includes. Method according to one of claims 4 to 9, characterized in that the drying in the coarse cleaning to a dew point temperature of 0 to 10 ° C, preferably 2 to 8 ° C, more preferably 4 to 6 ° C and in the fine cleaning to a dew point of -30 to 0 ° C, preferably -25 to -5 ° C, more preferably -20 to -10 ° C takes place. Method according to one of claims 1 to 10, characterized in that the fine desulfurization is carried out to a residual content of hydrogen sulfide of not more than 5 mg / m ³ . Method according to one of claims 1 to 11, characterized in that to ensure a uniform Rohbrennbiogasversorgung the rough cleaning a gas storage is connected upstream as a buffer tank. Method according to one of claims 1 to 12, characterized in that the at least one cogeneration plant supplied from the feed unit fuel gas flow has a calorific value between 6 and 12 kWh / m ³ . Composite system of plants for the production of anthropogenic and / or biogenic, methane-containing gases and combined heat and power plants for operation a natural gas network and to heat users for performing the method according to one of claims 1 to 13, characterized in that - at least one plant for the production of anthropogenic and / or biogenic, methane-containing gases is connected to a coarse cleaning unit, - to the coarse cleaning unit means for splitting of the coarse cleaning unit leaving the gas flow in a smaller volume flow and a larger volume flow, - the larger volume flow is introduced into a fine cleaning unit, - the purified gas stream is then introduced into a feed unit, - the feed unit, a device for odorization of the gas stream, means for measuring the Contains calorific value and the volume flow of the odorized gas stream and connected to the natural gas network means for mixing and metering of gases, - the feed unit is connected to at least one of the combined heat and power plants, the at least one heating provides heat, wherein the distance between the feed unit and the combined heat and power plants is greater than the distance between the combined heat and power plants and the respective heat users, and - the combined heat and power plants are connected to feed the generated electrical energy to the power grid. Composite system according to claim 14, characterized in that it is the plants for the production of anthropogenic and / or biogenic, methane-containing gases to biogas plants and / or landfill gas and / or wastewater treatment plants. Composite system according to claim 14 and 15, characterized in that the plants for the production of anthropogenic and / or biogenic, methane-containing gases comprise at least one biogas plant and the divided smaller volume flow of grossly purified raw combustion gas at least one cogeneration plant, which supplies the at least one biogas plant with heat supplied becomes. Composite system according to one of claims 14 to 16, characterized in that the coarse cleaning unit includes devices for coarse desulphurisation and / or drying of Rohbrennbiogases. Composite system according to one of claims 14 to 17, characterized in that the coarse cleaning unit additionally includes a device for membrane diffusion. Composite system according to one of claims 14 to 18, characterized in that the fine cleaning unit devices for fine desulfurization, drying and / or removal of silicon-containing compounds, in particular siloxanes, includes. Composite system according to claim 19, characterized in that the device for fine desulfurization comprises at least two reactors charged with potassium iodide impregnated activated carbon, which can be operated alternately.

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