How does a biogas plant work?

Summary

This video tour explains how BIO construct's biogas plants convert organic waste into renewable energy. The process begins with the delivery of substrates like maize silage, liquid manure, and industrial waste, which are blended and fed into fermenters. Inside these tanks, bacteria break down the material to produce methane, which is purified, compressed, and used to generate electricity and heat. The biogas is then utilized in combined heat and power stations, powering up to 1,000 households annually. The plant also produces high-quality fertilizer, benefiting both energy production and agricultural use while minimizing environmental impact.

Takeaways

• 😀 Biogas plants use controlled fermentation of biomass to produce methane, which can be converted into electricity and heat.
• 😀 Substrates such as liquid manure, agricultural products, and agroindustrial waste are commonly used in biogas plants.
• 😀 Silage maize is an energy-rich substrate used in biogas plants, and it is delivered to the plant via a hydraulic floor discharger and conveyor belt.
• 😀 Liquid manure is an important substrate in biogas plants, and it is pumped directly into blending pumps for mixing before fermentation.
• 😀 Food industry waste is also used as a substrate, and it is hygienized by heating it to 70°C before being pumped into the fermenters.
• 😀 Fermentation tanks, known as fermenters, are essential for methane production, where substrates are mixed and heated to accelerate gas formation.
• 😀 Biogas is created through a bacterial digestion process, where organic materials like fats and carbohydrates are broken down into methane.
• 😀 The biogas produced contains methane, carbon dioxide, water vapor, hydrogen, and hydrogen sulfide, which need to be treated before use.
• 😀 Biogas is purified through condensation, desulfurization, and drying processes to remove harmful substances like hydrogen sulfide and moisture.
• 😀 The biogas produced can be used in block heating and generating power stations, producing CO2-neutral electricity for up to 1,000 households.
• 😀 Biogas plants also create high-quality fertilizer from the substrates, improving the nutrient content and eliminating unpleasant odors in liquid manure.

Q & A

What are the main raw materials used in biogas plants?

The main raw materials, also known as substrates, used in biogas plants are silage maize, liquid manure, and waste from the food industry. These materials undergo fermentation to produce biogas.

How is maize silage processed in the biogas plant?

Maize silage is first tipped into a cement storage bin, from where it is fed onto a conveyor belt. The maize is mixed with other substrates in a blending pump and passed through mixing rollers before fermentation.

What role does liquid manure play in the biogas production process?

Liquid manure is one of the primary substrates used in biogas production. It is pumped into the blending pump, where it is mixed with other materials like maize silage before being transferred into fermenters for methane production.

How is the liquid waste from the food industry treated before being used in biogas production?

Liquid waste from the food industry is stored in large pits and then heated to 70°C in a heat exchanger to ensure hygienization, making it safe for fermentation in the biogas plant.

What is the role of the fermenters in the biogas production process?

Fermenters are where the substrates undergo fermentation, producing biogas. The substrates are continuously stirred, and the temperature is controlled to accelerate methane formation, typically over a period of 30 days.

What are the components of biogas, and why are some of them problematic?

Biogas consists of 50-70% methane, along with carbon dioxide, water vapor, hydrogen, and hydrogen sulfide. Hydrogen sulfide and water vapor are problematic because they can damage equipment and affect the quality of the gas.

How is hydrogen sulfide removed from the biogas?

Hydrogen sulfide is removed through a biological desulfurization process, where specific bacteria cultures decompose hydrogen sulfide into harmless sulfur and water.

How is the biogas compressed for energy generation?

The almost unpressurized biogas is fed into a compressor, where it is compressed to 70 bars to make it suitable for burning in engines, which generate electricity and heat.

What happens to the waste heat generated by the engines in the biogas plant?

Up to 30% of the waste heat from the engines is used to heat the fermenters, reducing the need for additional heating. The remaining heat can be used for heating industrial plants, houses, or swimming pools.

How is electricity from the biogas plant distributed and used?

The electricity generated by the block heating and generating plant is converted to the mains voltage level in a transformer, and then fed into the grid, supplying power to around 1,000 households annually.

How does the biogas plant ensure efficient and reliable operation?

The plant uses advanced measurement and control technologies for real-time monitoring. It allows remote access for troubleshooting and managing processes, ensuring optimal operation with minimal maintenance.