[Natalia Bourenane]

Question from @valor-method_adam

[Natalia Bourenane]

@lrenergy_rakshit @ibbk_michael @azuraassociates_trisha @azuraassociates_peter

[Nikolas]

Speaking from the biogas upgrading side, common issues are:

• Gas quality not up to spec post treatment (due to unexpected contaminants, mostly)
• Not enough flow coming out of the digester, which forces the compressors to operate intermittently

[Raymond]

I completely agree—these challenges are prevalent in real-world biogas upgrading operations. Fluctuating gas flow rates from digesters can lead to intermittent compressor operation, reducing efficiency and increasing wear.

This is precisely why implementing Variable Frequency Drive (VFD) flow control is crucial. VFDs adjust compressor speeds in real-time, accommodating varying inlet gas flows while optimizing power consumption. This not only ensures consistent gas quality but also enhances overall system efficiency. Accurate flow control has been shown to improve biogas resource efficiency significantly.

[Peter]

The five most common operation issues that we see are:

– Foam in Digesters or Receiving Tanks

– Hydrogen Sulfide in Biogas

– Ammonia in Digesters

– Odor Complaints

– Grit Accumulation in the Digester

Foam is an acute problem experienced by almost every digester that must be addressed by operators to avoid upsets, however it is a problem that can often be resolved quickly.

Hydrogen sulfide in biogas is growing as a concern for many facilities as they convert to RNG and must reach substantially lower targets in their product gas.

Ammonia concentrations will only be a problem for certain digesters receiving high nitrogen feedstocks,
however for those digesters managing ammonia will be an ongoing
challenge.

Odor complaints are also an acute problem, but can be avoided with the right technology and diligent operation.

Finally grit is not a problem that causes clear issues for an operator on any given day, however all digesters accumulate grit and must have a strategy to deal with it eventually.

We have an article with five more operational issues here on our website:

https://azuraassociates.com/commonly_overlooked_reasons_for_anaerobic_digester_failures/

azuraassociates.com

Commonly Overlooked Reasons for Anaerobic Digester Failures – AZURA

Commonly Overlooked Reasons for Anaerobic Digester Failures – AZURA