Consulting

Using cohesive strength, wall friction, compressibility, internal friction, and permeability test results, and in some cases, DEM (discrete element method) modeling, functional design recommendations including dimensions, angles, materials of construction, and feeder details are provided.
I can also design mass-flow screw feeders where the screw is comprised of tapered shaft and increasing pitch sections.

Rotary testers do a poor job of measuring wall friction, and permeability testers are difficult to find. I have drawings and parts lists for wall friction and permeability testers that can be fabricated from readily available, inexpensive components or I can recommend testers that are commercially available.
I can also supply Johanson Indicizers which are perfect for caking investigations.

I have access to Rocky DEM modeling tools to design transfer chutes and other equipment and testers to calibrate DEM inputs.
DEM can be misleading. I delegate DEM projects to experts in my network!

Biomass is variable and therefore challenging to handle. The key is to avoid convergence and/or include divergence in the bin and to design a feeder that ensures flow everywhere.

Caking problems are challenging because unwanted agglomeration is not always immediately evident. I can find causes and propose remedies. The adjacent photograph shows modifications to a 30-gal drum that reduces the compaction pressure inside.
I'm a strong proponent of Johanson Indicizers for tackling caking problems. Admittedly, they do not give a powder's true unconfined yield strength, but the results are repeatable and useful provided that they are not used in hopper design.

Gravimetric feeders are often unreliable because during the refill stage when new powder is added, stress is transmitted to the material in the feeder, increasing its bulk density. This causes the the discharge rate to increase. Once the controller returns to gravimetric mode, it recognizes the error and compensates, often overshooting due to outdated tuning parameters.
My design ensures that the solids stress in the feeder remains nearly constant during filling and emptying, allowing a constant bulk density and steady discharge rate.