Dry batch reactor
Municipal solid waste is loaded into the garage-type batch reactor by front loaders or trucks. Fermentation occurs without adding fresh substrates. This process is repeated regularly.
After loading the substrates, the reactor doors are hermetically sealed. The biomass inside is irrigated by nozzles with recirculating effluent liquid. Biogas is collected and pumped into a gas-holder.
Substrates are heated by pipes mounted in the walls and bottom of the reactor.
Anaerobic bacteria digest substrates, producing biogas.
The percolate is accumulated in a pit and pumped out by a pump.
The percolate is pumped out from the pit and accumulated in a percolate tank.
Biogas is collected in the gas-holder on the top of the percolate tank. The biogas is then dried in the chiller and pressurized by a gas compressor.
Sulfur is removed by means of an activated charcoal filter. Purified biogas is pumped for combustion into the co-generator.
Strictly speaking, no technology is dry. Fermentation always requires moisture. The method is called “dry” in comparison with other technologies since the mass is not pumped and is not blended with mixers.
The reactor is a reinforced concrete garage-type box. Typically, the mass moves with the help of pumps or mixers in a reactor. With the dry method, there are no mixers and the mass does not move, but instead, the mass is irrigated with percolate.
Percolate seeps through the mass, accumulates, and is pumped back into the percolate tank. Heating pipes are mounted inside the reactor’s walls and base.
The technology is characterized by low power consumption and low maintenance costs. In addition to the garage door itself and the percolate system, there is practically no other equipment such as mixers, pumps, or loaders.
The system is excellent for municipal solid waste (MSW), which contains a large amount of inclusions such as metal, plastic, and paper. These inclusions lead to frequent equipment breakdowns with other types of biogas technology. On the contrary, the contamination of raw materials in the dry method allows percolate to flow through the waste and is a necessary condition to work. In other biogas technologies, an expensive ultra-sorting and waste compaction module is required to avoid mixer and pump damage. And in the case of the dry method only, rough pre-sorting or no sorting is necessary.
- a garage-type reactor
- batch (periodic) operation without daily addition of fresh substrates
- no mixing devices or pumps
- heating by pipes inside the walls and inside the base
- sulfur removal by activated charcoal filters
- gas cooling in a chiller
- low power consumption up to just 3% of generation
- low maintenance costs. There is nothing to break