Zorg Biogas Service GmbH | Biogas technologies

Continuous stirred-tank

reactor

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 collecting

Biogas is collected and stored in a gas-holder on top of the reactor. Then it is dried, compressed by a gas blower, and pumped for combustion

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Substrate loading

Supply of substrates

Heating

Mixing

Digestion

Desulfurization

Biogas collecting

Technology Description

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

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

Moisture in a well-functioning CSTR biogas reactor is 93-97%. The organic dry matter load per m³ of reactor is 2-5 kg per day.

The technology is most often used for processing manure and dung. 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.