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2 BUILDERS FOLDER BIOGAS Imprint Publisher: LandesEnergieVerein Steiermark Burggasse 9 / II A-8010 Graz Tel: 0316 / Fax: 0316 / Responsible for the content: Gerhard Ulz

3 TABLE OF CONTENTS / 1 1. Foreword Future Biogas 2. Scope 2.1. Introduction 3. Definitions 4. Technology and operational organization of biogas plants 4.1. What is biogas? 4.2. Building units of a biogas plant 4.3. The most common plant systems Stirring tank fermenter Storage flow system based on gastight liquid manure storage Storage flow system with post-fermentation tank Plug flow fermenter Two-chamber system Simplified system comparison 4.4. Possible uses of biogas Gas combustion Combined heat and power (CHP) Fuel cell Micro gas turbine Other possible uses Feed-in natural gas network Use of fuel CO 2 generation 4.5. Hazards in biogas plants 4.6. Biogas potentials Biogas potentials in Austria Energy potentials in Styria 4.7. Advantages and disadvantages of biogas Ten good reasons for building a biogas plant Disadvantages of biogas plants 4.8. Profitability of biogas plants 4.9. Motives for the construction of biogas plants Content 1

4 CONTENTS / 2 5. Subsidies for biogas plants 6. How do I get a biogas plant in Styria? 7. Approval of biogas plants technical requirements 7.1. Mechanical requirements for biogas plants 7.2. Installation requirements for gas appliances and gas compressors 7.3. Structural requirements 7.4. Structural and organizational fire protection 7.5. Electrotechnical requirements 7.6. Explosion protection requirements 7.7. Emissions 7.8. Hygiene 7.9. Residues 8. Approval procedure 8.1. Regional planning procedure 8.2. Construction law Construction process 8.3. Approval according to gas law 8.4. Waste law Waste law permit 8.5. Electricity law Authorization according to energy law 8.6. Commercial license 8.7. Approval according to the Water Rights Act, Environmental Impact Assessment Act 8.9. Required submission / approval documents for the construction of an agricultural biogas plant Required submission / approval documents for the construction of a co-fermentation biogas plant Requirements according to the EU Hygiene Regulation 9. Monitoring of biogas plants 9.1. Periodic inspections (machine technology, electrical engineering, gas technology, lightning protection) 9.2. Responsible person content 2

5 10. Appendix TABLE OF CONTENTS / Map of Styrian Biogas Plants Documentation of Styrian Biogas Plants BG Auersbach BG Durlacher BG Pelzmann BG Kohlroser BG Fiedler BG Gschwaitl BG Steirerobst Gleisdorf BG NEGH Biostrom KEG Funding opportunities for biogas plants Land Steiermark Heat distribution Energetic optimization of wastewater treatment plants Research Energy generation from waste of biogenic origin Investment funding for purely agricultural biogas plants BMVIT Energy systems of the future BMWA Research and technology funding in Austria Framework program Energy of the European Union Green electricity tariffs Comparison of individual forms of company BGBl . II No. 508 / BMWA decree recognition of BG systems in accordance with 7 Ökostromges application form Recognition as a green power plant BG plants the most important laws and ordinances Biogas contact addresses in Styria Contents 3

6 1. FOREWORD THE FUTURE OF BIOGAS As a research and energy officer for the Styrian state government, I am very interested in the subject of the future of biogas. My vision is to use a modular biogas plant ready for series production to enable the use of this new technology in almost every municipality in order to get a comprehensive grip on an environmental disposal problem in addition to the energy supply. In addition, I consider the use of funds in research projects of the new biogas technologies to be very important, because I see biogas and the technologies associated with it as a beacon of hope for the Styrian business location, especially plant construction and eco-technology companies. This is in line with my credo that investing in innovation today will secure tomorrow's jobs. Beyond Styria, there is great sales potential for these technologies in the entire EU enlargement area, as I see it as a region of the future. A contribution to the Kyoto targets. Raw materials from agricultural fallow land, raw materials from disposal can replace fossil fuels as biogas and thus help to achieve the goals that we have set ourselves in the Kyoto Protocol, namely to minimize CO 2 emissions. An energy source with quality. If all the prerequisites are right: planning quality, quality of execution, a suitable political environment, if the framework conditions are favorable, then biogas can lead to a new quality of energy supply. A network for the future. In order to achieve all of these goals, I have endeavored to set the right course on the part of politics by setting up the Ökoenergie NOEST network as a one-stop-shop for innovative projects and research, which helps with advice and action as well as appropriate funding and to set another milestone with the presentation of this manual. With the development of biomass district heating, Styria has already made the best use of one opportunity. Biogas is the next. Let's use them together! Luck on LH Deputy DI Leopold Schöggl 1.

7 2. THIS FOLDER All new technologies, and as such I currently also consider biogas production, are faced with a large number of unanswered questions: It starts with the uncertainties about possible yields depending on the substrates used and goes beyond the necessary ones Process steps up to the legal requirements and necessities of the company. This biogas owner's folder, which is designed in such a way that it is possible to react quickly to changes and new findings, is intended to help reduce such uncertainties and give you guidelines on how to approach such a project. In addition, the document is not only aimed at the potential operator, but also at the companies commissioned with the planning and construction. The biogas owner's folder corresponds to the current state of knowledge in Styria and the current legal situation; it was therefore worked out with the Styrian authorities in particular in the approval area. In the future, brochures, conference documents and the latest research results will supplement this document and help you to stay up to date with the latest knowledge. In accordance with its mandate, the LandesEnergieVerein has always provided support for the introduction of renewable energies: District heating from biomass, for example, is a Styrian success story, and solar collectors are increasingly being used for domestic water heating and also for partially solar room heating. Now we want to help you to take advantage of the biogas opportunity. Gerhard Ulz, managing director of LEV Steiermark 2.

8 3. DEFINITIONS Substrate The raw materials that are intended for the biogas process in a biogas plant are called substrates, regardless of the properties and origin of the material. Water-rich, biogenic materials are particularly suitable, woody materials are not suitable. Co-fermentation With the decree of the Federal Minister of Economics and Labor regarding the approval of biogas plants according to 7 Green Electricity Act of, those substances are listed exhaustively with which a plant can be operated without co-fermentation (see Appendix 10.7.). All other substances fall into the field of co-fermentation. Biogas Biogas is an energy carrier with chemical binding energy, the main component of which is methane. It arises from the anaerobic (anaerobic = with exclusion of oxygen) microbial degradation of organic matter. Sewage gas and landfill gas are considered biogas in the sense of this basis. Biogas plant A plant for the production, processing, storage and / or use of biogas. Substrate storage This is understood to mean all storage containers for storing all substrates before they are fed to the biogas fermenter. Mixing tank It is used to mix and homogenize the substrates to be fed into the fermenter. The size and equipment (mixer, crushing equipment, pumps) depend on the substrates used. Fermenter This can be carried out standing or lying down. The size and type of design depends on the type and quantity of the substrates to be fed and the desired length of stay. The fermenter is heated, sealed gas-tight and equipped with a mixing device and a facility for extracting the biogas. Post-fermenter Like the main fermenter, this can be installed vertically or horizontally and is installed after the fermenter when viewed in the direction of flow of the substrate. The post-fermenter serves to completely break down the organic substance in the substrate and thus to produce the residual biogas still contained in the substrate. The size depends on the amount of substrates to be fed in and the desired length of stay. The secondary fermenter, like the main fermenter, is usually heated, sealed in a gastight manner and provided with a mixing device and a facility for removing the biogas. 3.

9 3. DEFINITIONS Repository It is used to store the fermentation residue until it is spread. The repository can be sealed gas-tight and serve as a post-fermenter in order to capture the biogas that is still being produced. Biogas storage facility It is used to temporarily store the biogas produced until it is used again. The biogas storage tank can be integrated into the fermenter or post-fermenter or set up separately. When gas is stored above the post-fermenter, it is covered with a film under which the gas can collect. Otherwise a gas collection bag will be installed outside the fermenter. Membrane gas container A container that is completely or partially closed by a plastic membrane and is used to store biogas. Double membrane gas tank A tank that is completely or partially closed by a plastic double membrane and is used to store biogas. The plastic double membrane consists of an inner membrane, which is flexible in its position and thus varies and delimits the gas storage volume. The outer membrane protects the storage tank against external influences. Combined heat and power plant The desulphurized and dried biogas is used in the combined heat and power plant. About 1/3 of the energy contained in the biogas is converted into electrical and about 2/3 into thermal energy. The electrical energy can be fed into the public electricity network, the heat can be used in the company or in the immediate vicinity. Fermentation residue This is understood to be the mixture of various substrates that accumulates in the repository after anaerobic fermentation in a biogas plant. This fermentation residue is a high-quality input substrate, provided that it is a valuable fertilizer for agriculture, which mainly contains nitrogen. 3.

10 4. OPERATING ORGANIZATION AND TECHNOLOGY OF BIOGAS PLANTS 4.1. What is biogas? Biogas is produced during the fermentation of organic substances such as liquid manure, dung, liquid manure, plants, leftovers, etc. in nature wherever oxygen is not allowed: in swamps and bogs or in the digestive tract of ruminants. In fermenters or digestion towers, anaerobic fermentation (anaerobic = without oxygen) produces biogas. If organic material is stored under exclusion of air (anaerobically), a biological process begins with the cooperation of methane-forming bacteria (cocci, rods, spirils, spirochetes, mycoplasmas and filamentous bacteria) in which a gas = biogas is produced. The biogas that is formed consists essentially of: substance methane carbon dioxide water vapor nitrogen oxygen hydrogen hydrogen sulfide ammonia chemical name CH 4 CO 2 H 2 ON 2 O 2 H 2 H 2 S NH 3 percentage <5 <2 <1 <2 <1 The calorific value per m 3 of biogas corresponds to around 6.4 kilowatt hours (kwh), depending on the methane content. Depending on the efficiency of the block-type thermal power station, this can generate up to 2 kWh of electricity and 2 kWh of heat (after deducting the process heat). Photo: Schmack Biogas AG 4.1.

11 4. TECHNOLOGY AND B.O. OF BIOGAS PLANTS 4.2. Building units of a biogas plant Basic structure: Every biogas plant consists of a number of sub-assemblies and individual building units around the fermenter. Biogas energy Biogas storage Main fermenter Post-fermenter Energy center (CHP) Mixing tank Final storage Substrate storage Fermentation residue Anaerobic fermentation 4.2.

12 4. TECHNOLOGY AND B.O. OF BIOGAS PLANTS 4.3. The most common plant systems The heart of every biogas plant is the fermenter. The design of the fermenter gives the biogas plant its name. For the sake of completeness, reference is made to the wide range of fermenter types and fermentation systems. Not all existing fermenter types have proven themselves in continuous operation, they are therefore not relevant in practice. Biogas plants could also be subdivided into individual plants, communal plants or large communal / industrial plants according to the type of operator (shareholding). Another distinguishing feature of biogas plants is the origin or the type of substrates used. In principle, they could be divided into agricultural biogas plants or co-fermentation plants. The most distinctive distinguishing features are found in the technical systems, which is why the subdivision according to the system technology is selected here. Basically, one can differentiate between biogas plants by the dry matter content of the biomass used. A distinction is primarily made between wet fermentation (dry matter content <15%) and dry fermentation (dry matter content%). Raw materials Dry fermentation Wet fermentation ANACON stirred tank fermenter Garage system Plug flow fermenter Hose system Two-chamber system Various other The terms continuous and discontinuous processes are often used in wet fermentation. In Europe, wet fermentation is the most common process in biogas plants based on the fermentation of pumpable starting substrates (dry matter content <15%). These types are again differentiated according to the type of construction as follows: 4.3.

13 4. TECHNOLOGY AND B.O. OF BIOGAS PLANTS stirred tank fermenters These types get their name from the necessary presence of stirrers in the fermenter room in order to be able to guarantee constant mixing of the substrates. In the field of biogas technology for agriculture, upright cylindrical designs are selected and used. Square and polygonal designs have not proven successful. Special designs, such as B. the egg shape or the cylinder with a conical end at the bottom as above, are more likely to be found in sewage treatment plants, where they are used as digestion towers. Today it is possible to build fermenter volumes of up to m 3 (and in special cases even more) and to operate them safely. The fermenters are mostly operated in the mesophilic (35 C - 38 C) or thermophilic (55 C - 60 C) range. Of course, this requires a functioning heating system in the fermenter. The multiple mixing of the substrate in the fermenter also does not really meet the environmental requirements of the individual bacterial groups (hydrolysis or methanogenesis). In practice, however, these suboptimal conditions are compensated for by relatively long residence times. The longer residence times lead to a certain dilution effect of the substrate in the fermenter. In addition, it is believed in practice that the individual groups of substances of the supplied substrate always have degradation times of different lengths, as a result of which an exact separation between hydrolysis and methane formation cannot be made in any case. In the field of stirred tank fermenter systems, different types are used in practice. Storage flow system based on gas-tight manure storage In the storage biogas plant, a standard concrete manure storage is built from concrete in formwork construction and expanded into a biogas plant. Storage and fermentation take place in one container. Storage flow system with repository and gas storage Source: LEA-Oststeiermark The charging takes place continuously. The advantage lies in the relatively small, compact system sizes. Recently, the biogas storage facility has also been integrated into this system

14 4. TECHNOLOGY AND B.O. OF BIOGAS PLANTS Storage flow system with post-fermenter This type is very popular in practice and the most widespread. Fermenter and post-fermenter form a unit and can be described as a closed system. Stable Pre-pit delivery and processing Spreading Storage flow system with post-fermenter Pump station Fermenter Post-fermenter (Source: Arge Biogas / BOKU) Energy utilization Combined heat and power plant Biogas storage With this system, the fermenter (as with the gastight liquid manure storage) is usually made of concrete using formwork. Recently, however, steel tanks have also been used more and more often as fermenters. The post digester is almost always made of concrete, but it can also be made of steel. Storage flow system with post-fermenter (source: Schmack Biogas AG)

15 4. TECHNOLOGY AND B.O. FROM BIOGAS PLANTS Plug-flow fermenter Better known in practice as a tube fermenter.Although this system also has a special agitator, this does not achieve uniform mixing, but forces the flow through the substrate in the form of a plug. The heart of the pipe fermenter is the axially arranged reel agitator. This agitator arrangement also determines the direction of flow of the substrate. In practice, there are different opinions about the optimal speed of the agitator. However, an average speed of one to four revolutions per minute can be assumed. The arms of the reel agitator should be arranged in such a way that they cover at least 95% of the fermentation chamber. The position of the agitator arm can vary from case to case. The agitating effect of the reel agitator is of particular importance so that the mixer slurry inflow slurry pump slurry, fresh inlet heating water flow gas extraction heat exchanger liquid manure fermented outlet stirring paddle heating water return pipe fermenter flow system with horizontal steel tank (plug flow fermenter) and liquid manure pre-pit (also suitable for solid manure). Source: Biogas brochure LEA-Oststeiermark production of small-scale flow turbulence is guaranteed. These flow turbulences are intensified by precisely defined switch-on intervals (quarterly or half-hourly are the rule). In this way, both the floating layers and the sinking layers can be prevented efficiently. In the plug-flow fermenter, the heater is either built into the agitator or, if the fermenter is designed as a double jacket, integrated into it. Both variants have advantages and disadvantages that have to be weighed up on a case-by-case basis. This continuously operated fermenter is characterized by a great variety of uses. In practice, the horizontal, sometimes slightly inclined, tubular design in steel or concrete is usually chosen. In steel construction, fermenter sizes between 50 m 3 and 150 m 3 are almost always installed, primarily for economic reasons. However, fermenters made of concrete can be built much larger. In contrast to the stirred tank fermenters, with the plug-flow fermenter the mixing of the entire fermenter content decreases with increasing substrate solids content. The aim is therefore to wander through the fermentation substrate in the shape of a plug, which does not allow longitudinal mixing. The feed, i.e. the amount and speed of passage through the fermenter, is determined by the pipe fermenter (source: Schmack Biogas AG) feed pump. The relative speed of separation increases with decreasing solids content. This leads to the following conclusion: The plug-flow fermenter is extremely poorly suited for the treatment of low-viscosity substrates and organically polluted waste water

16 4. TECHNOLOGY AND B.O. OF BIOGAS PLANTS Two-chamber system The two-chamber system is an Austrian invention and impresses with its pneumatic stirring technology, which is carried out with gas pressure. A mechanical agitator is no longer necessary. The size of the fermenter is variable and depends on the amount of substrate that is processed. Gas dome with autom. Mixing flap maximum sludge level Intermediate ceiling minimum sludge level Fresh substrate Main fermentation chamber Drainage shaft Post-fermentation chamber Drainage pipe Mixing shaft Feeding pipe Central pipe Two-chamber system (source: ENTEC) Mixing wing basic sludge removal The fermenter is divided into separate functional rooms. The lower-lying main fermentation chamber is connected to the post-fermentation chamber above by communicating shafts. These functional rooms are connected to a gas pipe near the ceiling. From the post-fermentation chamber, the gas produced is fed to the gas storage facility via a further line and then to be recycled. By locking the gas outlet from the main fermentation chamber, the released gas is compressed and pushes the surface of the substrate downwards. The thus displaced substrate is pressed into the post-fermentation chamber above. The active biomass can sediment there and is flushed back into the main fermentation chamber during the subsequent mixing process. This leads to an enrichment of the biomass in the fermenter, which causes a higher rate of degradation. After the desired mixed quantity has been reached, the excess gas pressure is released into the secondary fermentation chamber (by automatically opening the connection line) and the substrate conveyed upwards can briefly flow back into the main fermentation chamber. Substrate parts with strong buoyancy are pressed against the false ceiling, torn open and mixed in again, which results in repeated moisture penetration. Sandy deposits, such as mussel grit from chicken rearing, are removed via the basic sludge outlet

17 4. TECHNOLOGY AND B.O. OF BIOGAS PLANTS Simplified system comparison System comparisons are always difficult because the boundary conditions are usually very different. What are the strengths and weaknesses of the most common systems? Two-chamber system (ZS) Graft flow fermenter (PF) Storage flow system with post-fermenter (TMR) Monovalent substrate: ZS PF TMR Cattle manure Pig manure Chicken manure Solid manure thinly viscous viscous viscous viscous viscous viscous viscous Substrate mixtures: rumen vegetable sludge + 30% fatty sludge dry) Vegetable waste (wet) Food waste (dry) Food waste (wet) Energy crop silage (+ 30% with cattle, pork and chicken manure (> 4% dry matter [TS] and <10% TS) ZS Legend: Very good, good , moderate PF TMR

18 4. TECHNOLOGY AND B.O. OF BIOGAS PLANTS 4.4. Possible uses of biogas A number of technical solutions are available for using anaerobically generated biogas. Utilization of biogas Heat generation Combined heat and power methane processing By-product heat Electric power Fuel feed Natural gas network CO 2 use Gas combustion (heat generation) For decades, heat generation from biogas was almost the only technically feasible way of using biogas. Recently, this possibility of using biogas has been gradually replaced by combined heat and power. The use of biogas for pure heat generation via gas combustion is an economically interesting variant, since all other types of biogas utilization are considerably more expensive, both in terms of the provision of the technical equipment and in terms of ongoing operating costs. It does not make sense to store biogas for long periods of time. However, biogas is excellently suited to cover the daily peaks that occur, and a certain base load can also be covered. Another option for using biogas is to operate a biogas pipeline system to individual consumers. Due to technical problems with very small gas burners by z. B. fluctuating biogas composition, this possibility is currently hardly realized. If biogas is used for heating purposes, special gas burners are required (biogas burners without a fan, biogas burners with a fan). The area of ​​application depends primarily on the required output size, in principle all blower types are mainly used in combination with natural gas. In principle, however, the types can also be operated with biogas. At present, gas burners in biogas plants are primarily used as a safety unit in order to compensate for a possible downtime of the CHP and thus ensure a heat supply

19 4. TECHNOLOGY AND B.O. FROM BIOGAS PLANTS Combined heat and power (CHP) generation of electricity with the by-product heat. The term block-type thermal power station (CHP) is often used in this context. In this energy center, the biogas is converted into usable forms of energy in an internal combustion engine. In order to be able to operate a modern biogas plant economically, a well-functioning use of heat, ideally all year round, is of particular importance. Depending on the size of the plant, different types of engine and combustion processes (gasoline, diesel or pilot injection engines) are used to convert the biogas into electricity with waste heat recovery, and these differ significantly in terms of efficiency, service life and investment costs. Biogas generator See the diagram in the adjacent graphic: The cooling water as well as the hot exhaust gas are usually used to utilize the engine waste heat. The combustion engine sets a connected generator in motion, which generates electricity. Asynchronous generators, which are characterized by their robust construction, are mainly used to generate electricity. In the field of combined heat and power, the greatest efficiency can currently be achieved in the energy conversion of biogas. The overall efficiency (total) is around 85-90% of the energy used. The picture below shows the currently most common type of application, a special gas engine. The use of different technologies (gasoline engines, special gas engines or pilot injection engines) depends on various influencing factors. In the very small power range (<50 kW), converted petrol engines are primarily used. In larger power ranges, pilot injection engines and special gas engines are sometimes used. In the power range> 250 kW, special gas engines are primarily used. Motor cooling water circuit Exhaust gas consumer DHW heating CHP schematic block-type thermal power station (CHP) (source: LEA Oststeiermark)

20 4. TECHNOLOGY AND B.O. FROM BIOGAS PLANTS Fuel cells Fuel cells produce electricity and heat from the elements hydrogen and oxygen. The only reaction product of the electrochemical reaction is water vapor. However, the hydrogen first has to be provided; at present, fossil fuels (natural gas and methanol) or, alternatively, anaerobically produced biogas are used for this purpose. There are several types of fuel cells, which are differentiated according to the operating temperature and the type of membrane. The electrical output varies from 1 kw el. To 250 kw el. In the stationary area. Currently, fuel cells are mainly operated with fossil natural gas, and some research contracts also deal with the use of purified biogas. Fuel cells are used in areas where high electrical / mechanical efficiency is desired (power generation, vehicle propulsion). Source: TU Graz / IWT Micro gas turbine Micro gas turbines are small, high-speed gas turbines with low combustion chamber pressures and temperatures. They have developed from turbocharger technology and auxiliary drives in the aircraft industry and are mainly used as combined heat and power systems in decentralized energy supply in the power range below 200 kw el. Micro gas turbines are characterized by very low emissions, low noise levels and very low maintenance costs. Natural gas, biogas, liquid gas, flare gases and heating oil are possible fuels. For the use of biogas, the company Pro 2 Anlagentechnik GmbH offers a gas turbine with 95 kw el and the company Gas Energietechnologie GmbH offers a gas turbine with 28 kw el. Source: TU Graz / IWT Gas turbine 1. Generator 2. Air inlet 3. Compressor 4. Combustion air to the recuperator 5. Combustion chamber 6. Turbine 7. Recuperator 8. Exhaust gas 9. Exhaust gas heat exchanger 10. Exhaust gas outlet 11. Heating water outlet 12. Water inlet on the right in the section, on the left schematic