The increased interest in biorefinery has resulted in an ever growing interest in membrane filtration, which we at MoRe see from the number of enquiries and orders. The technique to filter certain components is also used more and more as the mills today try to close their systems in order to decrease water consumption.
The membrane technology enables dividing a liquid stream into different fractions where one fraction may be rubbish to one customer but valuable to another. The membrane technology is interesting and energy saving with a lot of applications, in future biorefinery blocks as well as when cleaning different process streams in pulp and paper mills. In the short perspective e.g. liquid streams with hemicellulose are interesting to membrane filtrate in order to pick out molecules which might be raw material for new products.
MoRe has a pilot plant for ceramic membranes which can withstand high temperatures, up to ca. 140°C today. Full size membranes are used, so data can be transferred to full-scale. We also have a pilot plant for plastic membranes, but here the temperature is limited to 40 – 80°C depending on membrane material, making them less suitable for hot process streams.
As different customers have different needs our pilot plant is flexible and can be run with different membranes depending on the customer’s wishes. For a simple test we need ca. 100-200 litres of liquid but we are also able to run continuously in the pilot plants for production of test quantities for the customers. Our longest run was 36 hours.
On a longer perspective membrane filtration, with units connected in series, could have the same function for non-distillable liquids as fractioned distillation has for an oil refinery. By formulating new processes which can dissolve the wood in a liquid phase, membrane filtration could separate different premium products for further processing. I believe that this might become an important method in future biorefineries to refine the wood to new, valuable products.
The ambition today is to close the processes as much as possible and to use as little raw water as possible. This makes it increasingly important to remove disturbing substances from process streams in the mills to be able to take care of these substances separately. Membrane filtration gives interesting possibilities to do this.