Thermal hydrolysis of excess biomass, such as sewage, creates a significant reduction in pathogens and vector attractors during the process. Conventional disposal to landfill is no longer required. With the TurboTec®, DMT Clear Gas Solutions can now utilize biomass as a source of producing renewable fertilizer.
Substances that are difficult to digest are hydrolyzed during the process. As a result, you receive more biogas from the same amount of biomass, with less biomass being left over after digestion. In addition, you can increase the biomass load going into digesters due to the change of hydrodynamics of the biomass.
The patented TurboTec® THP set-up, with mixing and separation, gives you a continuous configuration. The equipment operates under stable conditions, without idle periods for process equipment, which optimizes investment costs. Furthermore, auxiliary equipment and energy consumption are at a continuous operation tailored to the project demand. Configuration adjustments can be made depending on customer requirements to avoid any contact with pre-hydrolyzed and post-hydrolyzed material.
Pre-Treatment and Heat Exchanging
The raw biomass is sieved prior to entering the system. This can be done by, for example, static-drum or step-screening. This avoids operational downtime not only in the TurboTec® THP, but also in the digester and improves the quality of the final biomass all in one. After being sieved, the raw biomass is partially warmed up by utilizing heat from the outgoing hydrolyzed biomass. This can be done by the mixing-separation step, by heat exchangers or a combination of both.
The continuous flow of warm raw biomass is heated up with steam to 140–160°C and enters the reactor. Here, the material is retained for enough time to provide sufficient hydrolyzation. The reactor set-up is CSTR-style, meaning that the content is constantly in a turbulent environment. This way, all material is hydrolyzed, and accumulation is prevented.
After hydrolyzation, the biomass is cooled down either through contact with the raw sludge, the heat exchangers or both. It is now lower in viscosity, easier to pump and good to handle in conventional digesters. Due to the hydrolyzation, more phosphate and ammonia will be released in the digestate. This can be recovered in the form of struvite and ammonium sulfate.