Innovation provider

Loock Biogassysteme GmbH

Contact

Eiffestraße 585, 20537 Hamburg, Germany Tel.: + 49 (0) 40 / 34 0 - 9 34 Fax: + 49 (0) 40 / 34 0 - 2 12 E-Mail: info(at) loock-biogassysteme.de Internet: www.loock-biogassysteme.de

Description

Input:                        Biowaste (including contaminents)
Process:                  mesophil batch dry fermentation
Key features:         concrete-garage-like fermenters, percolate tank, CHP generator
Output:                     Biogas (electric power, heat), compost, separated contaminents
 
Loock TNS biogas plants consist of two main plant sections: dry fermenters constructed as reinforced concrete boxes and a high-volume process water reservoir.The process water circuit is kept strictly anaerobic and part of the biogas production takes place in the reservoir.
The substrates are inserted into the dry fermenters by wheel-loader or strewing carriages, where they are stored immovably during anaerobic processing.A (brief) aerobic preprocessing in the dry fermenter to increase the temperature and initiate decomposition of organic substances, is followed by the anaerobic phase. It is initiated by percolate being sprinkled from the process water reservoir top-down through the substrates.The process water percolates through the substrate, moving down and to the side through baffle plates with vertical perforations out of the substrate pile and is guided back into the process water reservoir.
Initially the percolate from the dry fermenter that has just been filled, is enriched by organic acids formed through hydrolysis.Nutrient movement out of the dry fermenters continuously supplies the process water reservoir with fresh organic acids, which in turn act as nutrients to methane-forming microorganisms.The microbiology, which is present in the process water, is used to inoculate the fresh substrate in the dry fermenters. The decomposition of organic acids as well as the acid buffer of the decomposition products neutralize the acids that are supplied with the percolate.Hence excess acidification in the dry fermenters is prevented.
As the processing duration of substrates in a dry fermenter is extended, hydrolysis activity decreases and ambient conditions improve for methanogenic bacteria.During this phase, the dry fermenter acts as a fixed bed reactor, supporting the anaerobic metabolism of excess acids contained in the percolate into biogas.
A staggered filling system of the fermenters ensures that some of the dry fermenters are always in the primarily hydrolytic phase, providing excess acid for the system, while others are in the primarily methanogenic phase, producing energy-rich biogas from the decomposition of acids.This and the evening out effect resulting from continuous production of biogas in the process water reservoir create a quasi-continuous process that ensures a sufficiently uniform supply of biogas to the decentral CHP plant.
When dry fermentation is terminated, the material is post-vented in the dry fermenter boxes. The patented combined aeration system with continuous bottom aeration and compressed air unit for compressed air jets at up to 15 bar ensures homogenous aeration of the substrate pile. The material is broken up at regular intervals in post-aeration to create new air channels for air that flows in from a side channel fan.
This combination ensures that no anaerobic nests remain in the substrate pile and that emissions of methane, ammonia and odour are minimized while the material is being removed. When the stackable digestate is discharged, not only is the gas space in the dry fermenter methane-free, new formation of methane in the fermentation residue is also suppressed. The Digestate is largely odor-neutral. It can be discharged with wheel-loaders and redirected for subsequent processing.

Advantages

  • Optimal biogas yield at low retention time

  • High annual throughput of substrates up to 16.5 times of the useable volume of dry fermenters

  • Minimal electric energy requirement of only 1 to 3 per cent of electricity produced

  • Low thermal energy requirement of only 10 to 15 per cent of thermal energy produced

  • Secure degasification and greatest possible deodorisation of fermentation residues

  • Maturity level of the digestates III to IV

  • No excess water

  • Flexible integration in existing plants at low capital costs

Innovative aspects (ecologic, social and economic)

  • Combination of dry fermentation with a percolate tank.

  • Effective dewatering of substrate heap allows for use of huge amounts of water for percolation process, organic acids from hydrolyses are effectively transferred to the liquid phase and to the process water circuit (percolate tank).

  • Large strictly anaerobic process water reservoir delivers continuously approx. 40% of biogas yield.

  • Combined aeration system assures complete degasification of dry fermenters including the substrate heap, terminates all anaerobic processes and may be used for drying of digestates inside the dry fermenter.

Application examples

Biowaste plants in Germany
Halle-Lochau
  • 50,000 t per year, therefrom 20,000 t per year of biowaste

  • 8 dry fermenters, each 240m³

  • 1 percolate tank with 1,200 m³

  • 1 wet fermenter with 2,600m³/1 second digester with 3,100m³

  • 2 gas engines with 526 kW electric power

  • In Operation since 2005

Nieheim 
  • 24,000 t per year

  • 8 dry fermenters, each 500 m³

  • 1 percolate tank with 1,200 m³

  • 3 pilot ignition engines with 2x 250 kW, 180 kW electric power

  • In Operation since 2007

Brandholz 
  • 8 dry fermenters, each 370 m³

  • 1 percolate tank with 1,200 m³

  • 2 gas engines, each 420 kW electric power

  • In Operation since 2007

Olderupfeld
  •  7,000 t per year

  • 4 dry fermenters, each 330 m³

  • 1 percolate tank with 1,200 m³

  • 2 pilot ignition engines, each 265 kW electric power (compatible with vegetable oil)

  • In Operation since 2007

Cost

Specific Invest for turn key digestion plants incl. delivery and logistic halls, CHP, biofilter system:

For 15.000 Mg/y biowaste approx. 220 EUR/Mg
For 30.000 Mg/y biowaste approx. 180 EUR/Mg
Operating costs (maintenance and repair, insurances, energy, operating agents, personnel):
For 15.000 Mg/y biowaste approx. 15-17 EUR/Mg
For 30.000 Mg/y biowaste approx. 12-13 EUR/Mg

Downloads

 

Current stage of development

Already on the market

Intellectual Property Rights

Patent applied for

Country of origin

Germany

Country of application

Year

2003

National Contact Point

Daniel de Graaf
Umweltbundesamt
Wörlitzer Platz 1
06844 Dessau-Roßlau

Tel. +49 (0)340 21033407
Fax. +49 (0)340 21043407

» daniel.degraaf@uba.de
» www.uba.de