Ultrafiltration plant, continuous

Industrial interest in soluble polymer-bound catalysts has been closely linked to the development of ultrafiltration membranes with sufficient long-term stability in organic solvents. Membranes fulfilling these requirements were prepared first in the late 1980s. Today, solvent-stable flat sheet membranes and membrane modules are available from several suppliers. As for the viability of ultrafiltration in organic solvents, rhodium-catalyzed hydroformylation of dicydopentadiene with continuous catalyst recovery and recycling has been demonstrated successfully on a pilot plant scale over an extended period of time [5]. The synthesis of other fine chemicals by asymmetric reduction and other reactions has also been carried out in continuously operated membrane reactors (also cf Section 7.5) [6-9]. The extent of commercial interest in catalysts bound to soluble polymers appears to fluctuate at intervals. Amongst other factors, the price of precious metals can be a driver. 

ABSTRACT Ultrafiltration membrane was used to treat Spent Filter Backwash Water (SFBW) of carbon filter and sand filter in a certain Water Treatment Plant (WTP). The results showed that the removal rate of turbidity by ultrafiltration was above 98%, the total bacteria count was less than 3 CFU/mL and the CODMn was about 1 mg/L. Ultrafiltration membrane ran stably when inflow flux was 60 L/(m h) and the cumulative water yield was about 1135 m after continuously running of 26 d, the reclamation rate was higher than 95% and the water producing cost was about 0.15 CNY/m. ... 

A similar climate exists for development of adhesives from Pinus radiata bark in Australia and New Zealand. A 22 ton/day bark extraction plant was built by New Zealand Forest Products Ltd. at Kinleith, New Zealand. These extracts have proved to be more difficult to use than wattle tannin due to their comparatively high molecular weight, the high viscosity of most extract preparations, their rapid rate of reaction with formaldehyde, and the often higher proportion of carbohydrate impurities. Current information (L. J. Porter, 1987) is that production of tannin by New Zealand Forest Products Ltd. has now ceased. In an attempt to make more uniform extracts with lower proportions of carbohydrates, ultrafiltration (257, 258) fractionation on Amberlite XAD-B gel (239), and fermentation (220) purifications have been investigated. Various reactions such as sulfonation and either acid- or base-catalyzed cleavage have been employed to reduce the viscosity of these extracts. A number of adhesive formulations based on P radiata bark extracts have been developed. However, technical difficulties continue to inhibit the commercial use of Pinus radiata bark extracts in wood adhesives. 

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