In a BDO production plant (butanediol process) 24 BoCross MicroScreen filter units of 10 m² each are applied for recovery of catalyst by dynamic precoat filtration.

The catalyst has to be recovered from a hot organic suspension which comes from 12 reactors. The catalyst consisting of inorganic solids has to be recycled to the reactors i.e. these particles have to be completely separated from the suspension. Particle range from 1–10 µm in size with a mean particle size of x₅₀ = 3µm. Main targets and requirements of this separation task are:

• recovery of catalyst
• particle-free filtrate
• no dilution of the suspension
• recirculation of catalyst into the process as fast as possible
• no air/gas contact of catalyst during separation and recirculation
• catalyst should remain suspended in the liquor.

The Chinese BDO-producer decided in favour of the DYNO Filter technology because of its ability to ensure a constant filtrate flow, a high catalyst content in the concentrate with the catalyst being suspended in the reactant and a short residence time of the catalyst outside the reactor, which is both crucial for an economic production process.