Zorg Biogas GmbH | Biogas technologies

Continuous stirred tank

reactors

Substrate loading

A frontal loader delivers substrates into a hopper where the inputs are crushed and fed to the horizontal auger. Next, the substrates are transported to the vertical auger.

Supply of substrates

Substrates are fed into the reactor by vertical and inclined augers.

Heating

The target temperature inside the reactor is maintained with heating pipes on the inner reactor walls.

Mixing

Substrates are constantly mixed with inclined and submersible mixers.

Digestion

Anaerobic bacteria digest the substrates, producing biogas.

Desulfurization

Sulfur is removed by means of a biofilter. To create the local aerobic conditions for sulfur-eating bacteria, air is supplied.

Biogas conditioning

Biogas is collected and stored in a gas-holder. Then it is dried, pressurized by a gas compressor, and pumped for combustion into the co-generator.

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Substrate loading

Supply of substrates

Heating

Mixing

Digestion

Desulfurization

Biogas conditioning

Technology Description

The classic CSTR technology (Continuous Stirred Tank Reactor) is simple and easily recognizable.

Distinctive features are the diameter of the reactor is greater than the height, heating by pipes on the reactor’s walls, a flexible gas holder above the reactor, sulfur removal by a biofilter from air in the center of the fermenter, mixing with inclined and submersible mixers. Reactors are made of either reinforced concrete or bolted steel panels.

Moisture in a well-functioning CSTR reactor is 93%. The organic dry matter load per m³ of reactor is 2-4 kg. Fermentation occurs in the mesophilic mode of 33° – 40° С.

The technology is most often used for processing manure, dung and stillage. A biogas plant with CSTR technology is often referred to as a “farm-style”. It is easy to maintain, which is especially important in rural areas, but less effective than other technologies. The degree of decomposition is 70% – 75%.