Efficient mixing and heating for digesters
The exclusive DIGESTMIX® system is capable of mixing and heating the content of a digester with minimal operating costs (energy and maintenance). This mixing and heating device facilitates stable temperature, intensive mixing and reduces and prevents of floating layers and foams inside the reactor. DIGESTMIX® can be set at the factory to only exercise in mixing mode. This device is located outside the reactor and allows a digester to be operated without internal moving parts. Excellent mixing conditions are a prerequisite for a continuous stirred tank reactor (CSTR) to maximize the contact of the anaerobic bacteria with the substrate to avoid bypass currents that could result in lower process efficiency. In a conventional digester, mixing is achieved by injection of biogas and/or propellers. In the case of DIGESTMIX®, an efficient mechanical mixing is obtained while avoiding the formation of layers of scum or foam on the surface of the reactor contents.
The DIGESTMIX® system mixes the contents of the CSTR by extracting the top layer of digestate inside the reactor and re-feeding it through a connection at the bottom. This setting prevents the buildup of floating layers. The DIGESTMIX® system is placed outside the reactor, prevents the occurrence of bypass currents and results in optimal mixing and heating inside the reactor. As a result of simultaneous heating and mixing, DIGESTMIX® facilitates optimal heat transfer and distribution within the reactor, leading to a very stable process operation.
This system allows introducing fresh substrate into the reactor with the help of DIGESTMIX®. In this way, optimum mixing is instantly achieved. The innovative hydraulic design of the system ensures a very moderate energy consumption. The absence of mechanical parts inside the reactor greatly simplifies the maintenance of the system. The tube-in-tube heat exchanger cannot be clogged, and system deterioration is very limited. For maintenance purposes, the system can be shut down while the reactor remains in operation and biogas production continues. In addition, for carrying out maintenance, there is no need to open and/or enter the reactor. Because of the optimal mixing, very stable process conditions are established for the digester.