Netzsch presented its NEMO® B.Max® progressing cavity pump as the feeding technology which is perfectly tailored to biogas applications. Solids from the dosing unit are mixed with recirculated substances in the mixing pump. The homogeneous mixture with a dry matter content of up to 25% is then conveyed to the fermenter.
Ideal feeding and mixing
The NEMO® B.Max® provides twofold assurance of optimum product feed into the conveying chamber: its pump housing is fitted with a large, rectangular feed hopper and removable, conically shaped compression chamber, as well as a coupling rod with patented, horizontally positioned conveying screw. This conveys quantities of up to 75 m3/h at pressures of up to 48 bar. Ideal feeding and mixing of the substrates into the biomass are ensured by the spiral lobes of the mixing and screw conveyor, which have been strengthened and offset.
This not only prevents bridging, but also leads to optimum mixing of the liquid phase and dry substrate in the hopper chamber. At the same time, the feed tube, installed on the hopper housing contra to the flow direction of the pump, also ensures improved substrate mixing – which means a higher gas yield as well.
NETZSCH designers have achieved compact dimensioning, low overall weight and constant shaft height, irrespective of the design and size of the drive, by flanging the drive directly to the pump's lantern. The system can be flexibly adjusted to the dosage unit in each case through the various hopper lengths on offer. Numerous inspection openings in the hopper and compression chamber of the NEMO® B.Max® make it easier for operators to carry out inspection and maintenance.
In the event of the pipework getting clogged up, the NETZSCH mixing pump has no problem flushing this out with a pressure of up to 12 bar, as the NEMO® B.Max®, with its two-stage construction, is also designed for high back pressures. The speed can be adjusted on the NEMO® B.Max® using a frequency inverter. This means the system can be flexibly adjusted to suit various raw materials, the mix ratio of the substrate and feed times.
The NEMO® B.Max® is particularly well suited to fermented, renewable raw materials, macerated biological waste, food waste and sugar beet, co-substrates, whole plant, maize and grass silage, solid manure, dry chicken manure and liquid manure.