Viscosity control: the key to keep the efficiency of your biogas/biomethane plant always high

The hydraulic management of a biogas plant is a crucial point: viscosity control is the key to an efficient plant and high yield.

Plant operators have begun to use by-products and waste derived from agricultural, municipal, and agro-food industry activities for gas production, in order to reduce production costs or to comply with production regimes. Most of these wastes have a high fiber, cellulose, lignin, pectin, concentration which make them hard to be digest by bacteria. These components normally tend to float on the digester surface, creating crusts that compromise the plant hydraulic management. Generally, plant designers and operators tend to dilute the solid concentration in the digesters to compensate the inefficiency. Under this condition, the retention time increases and thus the digestate volume. It results in reduced plant efficiency and gas yield. Therefore, pretreatment systems are needed that enhance the use of these byproducts by improving their mixing in digesters and their production efficiency under standard plant retention times.

Biomass pretreatment in biogas and biomethane plants can be splitted into 2 phases:

• Pretreatment on the feeding line: it coarsely chops the solid biomass and mixes it with the liquid to facilitate physical loading into the digesters.
• Process pretreatment: It intercepts in the digesters the biomass fraction that resists the first digestion stages and tends to float on surface. This is a “fine” disgregation and homogenization process that allows to maximize plant’s hydraulic efficiency and yield.

BioBANG^® technology, works in recirculation as a pre-treatment process. The suction phase is installed in the digester upper part where there is 10-20% of difficult biomass that, stratifying on the surface reduces the plant yield. In one step, it’s recirculated to the bottom of the digester, ready to be immediately involved in the digestion process like the rest of the feed, without competing with bacteria.

BioBANG^® in recirculation maximizes the yield and hydraulic management of the plant, optimizing its energy efficiency. In fact, the energy of the treatment is totally recovered by reducing the mixing and pumping energy consumption. Viscosity control becomes the strong point for an efficiency and yield that cannot be compared to a plant without BioBANG^®.