Trouble free and more efficiency biogas production due to liquid feeding system
Case Study - Ronconi Giacomo biogas plant, Italy


Solid matter preparation and feeding on a 1 MW biogas plant


Vogelsang PreMix ®

The customer and the application

“Ours is a large livestock farm, consisting of a pig farm with 130 thousand pigs and a dairy barn with 2.0000 cows. To complete our activities, we have built two 1 MW biogas plants which we feed with slurry, cattle dung, process water out of the company and a small share of silages. Booth anaerobic digestion plants are fed with the same input material - but with two deeply different feeding systems. While we install at the first plant a vertical mixer with screw conveyor to feed the solids dry direct into the digester, we use a liquid feeding system at the second plant, so the substrates are feed well mashed with a liquid into the digester.”

The product

At the second plant, Ronconi install a Vogelsang PreMix solid matter feeder to prepare and mash the input material. The PreMix receives the solid matter from a screw conveyor. In a single operation, it chop down fibrous residues, eliminates foreign bodies and mixes the solid matter with digestate or slurry into a homogeneous suspension and feed them into the digester.

After more than two years of operation – the startup of the system was in January 2018 - Mr. Giovanni Ronconi was possible, numbers in hand, to make a comparison between the two methods and analyzing production results and management differences.
“What is most evident is the very clear reduction in manpower for maintenance of the digester and mixers, which in the plant without pre-mixing must be extracted approximately every month to remove ropes and straw stalks, while the digester with PreMix has never requested such actions. The maintenance of the machine itself is also a minimum: so far, we don´t need to carry out any intervention on the progressive cavity pump, while due to wear, on the macerator only the knives and sieve has been replaced. At the same time, the liquid feeding system avoids the formation of layers and improves the gas yield. Therefore, it is possible to reduce the quantities of input material without penalizing the daily production. Finally, PreMix requires less energy than the vertical mixer and reduces also the energy requirements of the mixers, which are no longer forced to handle long-fiber materials as
occurs with manure," sums up Mr. Giovanni Ronconi.

Advantages of the Vogelsang PreMix…

  • Mashes biomass with a liquid to form a homogeneous organic suspension suitable for bacteria
  • Separates out heavy material and chop down fibrous harmful matter
  • Easy and quick service on site

Benefits for the user

  • Clear reduction in manpower for maintenance of the digester and mixers
  • Layers in digester are avoided
  • Less energy consumption of the feeding system and mixers
  • Reduced quantities of input material needed

Mentioned Vogelsang products

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