A frontal loader delivers substrates into the hopper where they 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 with vertical and inclined augers.
The set temperature inside the reactor is maintained with heating pipes on the inner reactor walls.
The substrate is periodically mixed using the vertical or inclined robust mixers. The mixers have been specially designed for mixing a thick and viscous mass.
Anaerobic bacteria digest the substrates, producing biogas.
In the summer, the reactors are not heated but cooled instead.
Biogas is collected and stored in a gasholder on top of a post-digestor or outside of digestors. Biogas is then dried in a chiller and pressurized by a gas compressor.
Sulfur is removed by means of an activated charcoal filter. Cleaned biogas is pumped for combustion into a co-generator.
A feature of high-load reactors is high-solid content in the reactor up to 16%. The mass is so thick that a stone weighing 10 kg does not sink on the surface immediately. The organic dry matter load is 5-15 kg per m3 of reactor, which is twice to three times as high as that of a reactor with the classic CSTR technology.
To mix the thick mass, patented high-load mixers are used which allow hot repairs without shutting down the reactor.
Fermentation occurs in the thermophilic mode of 44° – 55° С. In this mode, operation is safe during the summertime. Unlike a classical reactor, the high-load reactor does not need to be heated but instead, to be cooled as required. A higher operational temperature provides a deeper substrate decomposition resulting in a greater biogas output.
Due to the high load of the reactor, the capital costs are reduced by 1.5 times compared with the classical technology. These plants are very robust, and this technology is particularly well-suited for high-calorie raw materials such as maize silage or grass.
- high load of organic dry matter (ODM) up to 15 kg per m³ of reactor,
- high solids content in the reactor up to 16%,
- heating using pipes on the walls of the reactor,
- supply of raw materials input by screw feeders,
- thermophilic modes 44° – 55° C,
- not only heating, but also reactor cooling,
- sulfur removal by activated charcoal filters,
- cooling of biogas in a chiller.