The Potential of the HybSi Ceramic Membrane In Process Intensification

The potential of the HybSi ceramic membrane in process intensification

Author: Frans Velterop

Company: Pervatech BV

The HybSi membrane exhibits increased stability and longer lifetimes in acidic environments, with aggressive organic solvents and at higher temperatures compared to polymeric and other ceramic membranes.

 

The HybSi membrane is effective for separating azeotropic water/organic mixtures, in dewatering of industrial solvents and separating low-molecular-weight compounds (such as CH3OH and NH3) from higher-molecular-weight solvents. In addition, the HybSi membrane can be used for in situ dehydration of condensation reaction mixtures.

 

The HybSi membrane can be used in pervaporation and in vapour permeation mode, with preference to vapour permeation mode, because all solids and ionic compounds are eliminated and throughput at elevated temperature >> 100ēC is strongly enhanced.

 

The stability in acidic environment gives HybSi the advantage to be used in esterification processes where often organic acids are the homogeneous catalyst. No other membrane is able to carry out separation at elevated temperature in the presence of acidic homogeneous  catalysts. Polymeric membranes with micro-porous construction of the separation layer are limited to < 100ēC or cannot withstand the complex composition of the reaction mixture.

Zeolite membranes can take the elevated temperature, but disintegrate in the presence of homogeneous catalysts, hence only HybSi is robust enough to survive those extreme process conditions.

 

The most appealing process where HybSi is unrivalled the best possible process for effective separation is in combination with esterification processes, were water is liberated.

Even more pronounced is the advantage when the esterification process liberates water plus  one of the reactants is methanol.

The yield of the reaction is often very limited, even below 50%, but when water is removed the yield can go up to 75^% to 90%. Potentially even approaching 100%, but for that all other process conditions must be at optimal values.

In the formation of methyl-esters methanol is added in large excess to enforce the reaction to proceed. However when the HybSi membrane is applied in situ during the reaction, not only the liberated water will be removed, but also the excess of methanol is taken out, enforcing the equilibrium to the right, increasing the yield and minimising the down stream processing.

 

Examples will be presented of the unrivalled advantages of HybSi in dehydration of azeotropic mixtures and in esterification reactions.

 

Keywords: HybSi, Ceramic, dehydration, esterification