Success Story: Optimization of the anaerobic digestion process for biogas generation

NCC presenting the success story

NCC Spain

Client/user profile:

NORVENTO is a company focused on the promotion and development of energy production facilities based on renewable energies (wind, sun and biomass), as well as in the manufacture of wind turbines. ENERGYLAB is a Spanish (non-profit) private technology center specialized in energy efficiency and sustainability, including research topics related to biogas.

Impact:

Design and optimization developed tools allow Norvento to reduce volume and cost of industrial anaerobic digesters, increasing the amount and quality of the produced biogas while reducing the energy consumption (needed for mixing and heating). As a result, Norvento renewable energy power plants are able to increase their electrical and thermal production.

For Norvento, a cost reduction in investment and maintenance as a direct outcome of reduced size digesters, will improve and support a profitable and sustainable business, and favour new business lines, such as the implementation of on-site digesters for cattle raising installations.

EnergyLab obtained a valuable knowledge of fluid-dynamics, HPC and simulation models. Potentially, new services focused on energy efficiency, based on the HPC simulation tools developed, can be set up and included in the EnergyLab service portfolio.

Technical/scientific Challenge:

Anaerobic digestion is the process by which microorganisms degrade organic matter in the absence of oxygen, producing a methane-rich biogas stream that can be used for energy generation. Industrially this process takes place in large full tanks called anaerobic digesters. The main motivation was to prove that an optimal energy balance between energy consumption and production can be achieved in small-scale anaerobic digesters.

Solution:

A new open-source based solution that allows the simulation of flow (fluid dynamics) and biological aspects of an anaerobic digester was developed. Due to the scales involved in the process (300 m3 for anaerobic digester and particles around 0.01 cm3), the numerical solution of this coupled problem is very complex. Highly refined meshes are needed, which results in large computation times. Consequently, the solution requires HPC capabilities to provide results in an affordable time which model the engineering processes.

Key points before agreeing on project:

• Data confidentiality
• NDA