The facility is equipped with a 450-kW cogeneration power plant
A biogas plant of WELTEC BIOPOWER recently went live in Saitama Prefecture, 40 km north of Tokyo. The facility, which is equipped with a 450-kW cogeneration power plant, is the fourth project to be rolled out by the German manufacturer in Japan. In terms of substrates, the operator makes use of organic leftovers from the vicinity. Since the raw material mix varies, WELTEC ensures a steady biogas output with its biological service. This special service of the biogas specialist also comprises another plant of the same customer.
Even after the reactor accident in Fukushima back in 2011, Japan continues to use nuclear power. However, renewable energies are consistently expanded and already account for a fifth of the power generated. Above all, leftovers are the preferred substrates in Japan.
The biogas plant in Saitama, too, digests some 12,000 tonne of organic waste into energy. The substrate mix consists of organic waste and cattle manure from a nearby farm that belongs to the operator. The largely liquid organics are introduced to the digester using a central ump. Solid feedstocks are transported by a dosing feeder with a capacity of 27 m³.
To ensure efficient digestion of this mixture, WELTEC BIOPOWER has set up a stainless-steel digester with a capacity of 2,823 m³. Its diameter measures 25.34 m, and its height is 6.3 m. The upstream substrate storage tank, which is made of stainless steel, has a capacity of 336 m³, a diameter of 9.31 m and a height of 5.03 m. The 525-m³ digestate storage tank (diameter 11.64 m, height 5.03 m), too, is made of high-quality stainless steel.
Finally, the digestate is separated and the solid phase is dried with special technology to further reduce the volume. Most of this residue is used as compost and some of it as fertiliser.
As this plant‘s yield was above average, the biology experts of WELTEC had the substrate mix of the old plant carefully analysed by a Japanese lab. Based on the results, the raw material mix and the retention time have been optimised. Due to the constantly changing composition of the waste, WELTEC will continue to supervise the two plants biologically to maximise the gas yield.
