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Abstract

Efforts were made to demonstrate that in biorefineries it is possible to manufacture all the commodities required for maintaining human civilisation on the current level. Biorefineries are based on processing biomass resulting from photosynthesis. From sugars, oils and proteins, a variety of food, feed, nutrients, pharmaceuticals, polymers, chemicals and fuels can further be produced. Production in biorefineries must be based on a few rules to fulfil sustainable development: all raw materials are derived from biomass, all products are biodegradable and production methods are in accordance with the principles of Green Chemistry and Clean Technology. The paper presents a summary of state-of-the-art concerning biorefineries, production methods and product range of leading companies in the world that are already implemented. Potential risks caused by the development of biorefineries, such as: insecurities of food and feed production, uncontrolled changes in global production profiles, monocultures, eutrophication, etc., were also highlighted in this paper. It was stressed that the sustainable development is not only an alternative point of view but is our condition to survive.
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Abstract

The knowledge about membrane contactors is growing rapidly but is still insufficient for a reliable designing. This paper presents a new type of membrane contactors that are integrated with one of the following ways of separation by using absorbents, micelles, flocculants, functionalized polymers, molecular imprints, or other methods that are based on aggregation. The article discusses methods for designing multi-stage cascade, usually counter-current. At every stage of this cascade, relevant aggregates are retained by the membrane, while the permeate passes freely through membrane. The process takes place in the membrane boundary layer with a local cross-flow of the permeate and the retentate. So the whole system can be called a cross-counter-current. The process kinetics, k, must be coordinated with the permeate flux, J, and the rate of surface renewal of the sorbent on the membrane surface, s. This can be done by using ordinary back-flushing or relevant hydrodynamic method of sweeping, such as: turbulences, shear stresses or lifting forces. A surface renewal model has been applied to adjust the optimal process conditions to sorbent kinetics. The experimental results confirmed the correctness of the model and its suitability for design of the new type of contactors.
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