Wie funktioniert eine Biogasanlage?

Biogas Production Process Overview

Introduction to Biogas and Its Benefits

• Biogas is produced from renewable resources and organic waste, serving as a sustainable energy source that can be stored and regulated on a large scale.

• The process involves generating electricity and heat through combined heat and power (CHP) plants, which can also upgrade biogas for injection into the natural gas grid.

Input Materials for Biogas Production

• Renewable raw materials such as agricultural products, animal manure, and food industry by-products are utilized as inputs in biogas facilities.

• Corn silage is specifically mentioned as an input material; it is delivered to the facility via a loader into a storage bunker designed for two days of retention.

Mixing and Preparation of Substrates

• A push floor system transports corn silage to a mixing container where additional agricultural or industrial by-products can be added using various techniques like vertical mixers.

• Liquid components, such as slurry, are pumped into designated containers until needed; industrial waste must undergo hygienization at over 70°C to eliminate pathogens before use.

Fermentation Process

• The mixture undergoes fermentation in an anaerobic environment within the fermenter, where bacteria break down materials over approximately 60 to 70 days at mesophilic temperatures (35–38°C). This process generates biogas efficiently with low energy consumption.

• A recirculation shaft allows for reintroducing processed material back into the mixing container, optimizing resource use by reducing the need for additional liquid inputs.

Equipment Design and Functionality

• Envitec's modular design using precast concrete parts offers flexibility in construction tailored to customer needs while maintaining consistent temperature control within the fermenter through stainless steel heating systems.

• Adjustable stirring mechanisms ensure thorough mixing of substrates without hindering maintenance operations during ongoing processes. Additionally, specialized roofs with integrated gas storage enhance safety standards against snow load and wind pressure.

Gas Treatment and Utilization

• To remove hydrogen sulfide from biogas, air oxygen is introduced biologically within the fermenter; this process utilizes sulfur-reducing bacteria effectively. The resulting digestate is stored in a gas-tight tank for later use as high-quality fertilizer after nutrient preservation during fermentation.

• The produced biogas is cooled and dewatered before being analyzed for quality; it then enters a gas compressor to increase pressure for utilization in CHP systems or excess management via emergency flares when necessary conditions arise.

Biogas Processing and Utilization

Aktivkohlefilter (Activated Carbon Filter)

• The activated carbon filter is designed to remove residual hydrogen sulfide from pre-desulfurized biogas. Monitoring the concentration of hydrogen sulfide helps determine when the filter needs replacement.

Biogas Combustion in BHKW

• In the combined heat and power plant (BHKW), biogas is combusted using a gas engine specifically developed for this type of gas, converting it into electricity and heat.

• To minimize noise during operation, the BHKW is housed within a soundproof cabin located inside the technical building.

Emission Control and Energy Distribution

• The exhaust gases produced during combustion pass through a catalyst designed for Envitec systems to reduce formaldehyde emissions.

• Generated electricity is transformed to grid voltage via a transformer before being fed into the public network.

Thermal Energy Applications

• Thermal energy generated can be utilized for heating various facilities such as farm buildings, greenhouses, or even entire settlements based on demand and system size.

• A portion of this thermal energy is also redirected to heat the fermenter, enhancing efficiency in biogas production.

Input Management and Operational Control

• Input materials' mixing times, feeding intervals, and daily quantities can be managed via computer input, allowing for continuous monitoring and adjustments.

• Any operational disturbances are immediately reported, enabling prompt resolution by operators who maintain oversight of all critical parameters in real-time.