Use of Filter Aids to Improve the Filterability of Enzymatically Hydrolyzed Biomass Suspensions

Abstract

Filter aids are used in challenging filtration applications, such as the deliquoring of biomass suspensions and separation of fine particles from liquids. Organic filter aids, typically composed of cellulose, may be the preferred option in the case of bioprocesses, because their energy content can be recovered together with the primary filter cake. In this study, a laboratory scale pressure filter was used in order to investigate the effect of various filter aids on the filtration of an enzymatically hydrolyzed biomass suspension. Various organic and inorganic filter aids were used in two modes: as a body feed and as a precoat. According to the results, the average specific resistance of the cakes could be best reduced using the body feed mode. Filter aids also helped to reduce the moisture content of the cakes and to increase the corresponding filtration capacities. Additionally, a process scheme enabling utilization of the solids was proposed.

Dewatering of Micro- and Nanofibrillated Cellulose for Membrane Production

“…However, SR and CSF methods have the potential to underestimate resistances as nanomaterial can be lost through coarser filtration wire used for these experiments, and additionally for fundamental studies these empirical measurements and values are of little fundamental value. Nonetheless, more recent investigations have established cake resistance values for a variety of fiber with and without additives. − The presence of fines and additives, the degree of beating, and fiber length are well-known to impact the dewatering times of dispersions of cellulose fibers. As a result, the cake resistance of cellulose fiber mats can range dramatically from 10 9 to 10 12 m/kg.…”

Oxygen Transfer in High Solids Loading and Highly Viscous Lignocellulose Hydrolysates

“…14,15 However, the solid/ liquid separation for a highly viscous hydrolysate has been proved to be a tough operation: Centrifugation is not practical in industrial operation due to the very high solids content of the hydrolysate, and filtration is extremely difficult to perform because of the very high viscosity. 16,17 Furthermore, heavy loss of fermentable sugars and high electricity input are inevitable if solid/liquid separation is performed. In fact, at least a partial reason for the simultaneous saccharification and fermentation (SSF) operation in biorefining fermentations is due to the difficulty of and heavy loss of sugars from solid/liquid separation; therefore, the solid particles containing hydrolysate slurry directly go to fermentations without solid/liquid separation.…”

“…In the high solids loading and highly viscous lignocellulose hydrolysates, fine air bubbles tend to aggregate into larger bubbles and quickly escape from the hydrolysate slurry. − The aggregation and escape of the bubbles decrease the overall gas holdup, the gas–liquid interfacial area, and the interface mobility of the high viscosity and solids loading hydrolysate slurry . These phenomena correspondingly reduce the oxygen transfer rate and cell metabolism activity. , One way to improve the oxygen transfer property is to remove the solid particles from the hydrolysate slurry. , However, the solid/liquid separation for a highly viscous hydrolysate has been proved to be a tough operation: Centrifugation is not practical in industrial operation due to the very high solids content of the hydrolysate, and filtration is extremely difficult to perform because of the very high viscosity. , Furthermore, heavy loss of fermentable sugars and high electricity input are inevitable if solid/liquid separation is performed. In fact, at least a partial reason for the simultaneous saccharification and fermentation (SSF) operation in biorefining fermentations is due to the difficulty of and heavy loss of sugars from solid/liquid separation; therefore, the solid particles containing hydrolysate slurry directly go to fermentations without solid/liquid separation.…”

A low-cost solid–liquid separation process for enzymatically hydrolyzed corn stover slurries

“…Only a few separation studies have been published for these materials. Kinnarinen et al (2013) examined the use of cellulosic filter-aids with pressure filtration and observed modest improvements. Another study evaluated the use of polyelectrolyte flocculants with pretreated and enzymatically hydrolyzed pine and obtained 12× improved centrifugation separation performance and 40× flux improvement in a vacuum filtration assembly (Burke et al, 2011).…”