The ProKris Technology

Developments such as the Common Agricultural Policy reform, growth of the bio-based economy, increasing energy prices, increasing sustainability demands, and expected growth of global sugar demand change the environment in which the sugar producing industry operates. (source: artikel van Ruben Kolfschoten: “Opportunities for small-scale biorefinery for production of sugar and ethanol in the Netherlands) In the traditional process, after sugar beet cultivation, the beets are transported from the farmland to a storage facility from where they are transported to the centralized refinery. Here the sugar beets and residues will be processed as shown in figure X. Since sugar beets contain over 75% water, the environmental costs of transporting beets over long distances to the centralized refineries are tremendous.

The ProKris Technology

Developments such as the Common Agricultural Policy reform, growth of the bio-based economy, increasing energy prices, increasing sustainability demands, and expected growth of global sugar demand change the environment in which the sugar producing industry operates (source: artikel van Ruben Kolfschoten: “Opportunities for small-scale biorefinery for production of sugar and ethanol in the Netherlands). In the traditional process, after sugar beet cultivation, the beets are transported from the farmland to a storage facility from where they are transported to the centralized refinery. Here the sugar beets and residues will be processed as shown in figure X. Since sugar beets contain over 75% water, the environmental costs of transporting beets over long distances to the centralized refineries are tremendous.

In a traditional sugar refinery, the sugar beets are first washed and sliced into cossettes after which the sugar is extracted from the cossettes via diffusion and crude juice is obtained. By a carbonatation step with lime the impurities are removed leading to the formation of lime fertiliser and thin juice, which will be evaporated to obtain thick juice. The thick juice is heated to evaporate all the water, after which crystallization of sugar is obtained. Since sugar dissolves extremely well in water (up to 5 kg of sugar per litre of boiler water), the water must be removed almost completely to make the sugar crystallize. Without solvent (the water), the remaining liquid becomes very high in viscosity and the sugar crystals don’t settle by gravity anymore. As a result, the sugar crystals have to be separated from the remaining liquid (molasses) via energy-intensive centrifugation.

Prokris technologies revolve around an innovative technique to crystallize sugars: Anti-Solvent Crystallization. Via addition of an anti-solvent the solubility of sugar in water is lowered, allowing the crystallization to occur at relatively high water concentrations. The novelty of the Prokris technology is that steps 2, 3 and 4 can be replaced by a much more efficient 1-step anti-solvent crystallization phase. White sugar can be derived directly from the crude juice, avoiding the necessity of the environmentally demanding carbonatation step while lowering the energy costs for water evaporation. Since the viscosity of the anti-solvent/sugar/water mixture is much lower than a sugar/water mixture, the sugar crystals can be harvested without the need for energy intensive centrifugation. Besides, within the ProKris technology the anti-solvent can be recovered from the mixture and reused in the system. Overall, the Prokris system has three main advantages over the traditional process:

  1. It is a simple and very energy-efficient process, which
  2. Produces the same sugar quality at (much) lower cost and thus
  3. Creates a competitive small-scale solution to extract sugar from sugar beets or sugar-containing by-products.

Prokris technologies revolve around an innovative technique to crystallize sugars: Anti-Solvent Crystallization. Via addition of an anti-solvent the solubility of sugar in water is lowered, allowing the crystallization to occur at relatively high water concentrations. The novelty of the Prokris technology is that steps 2, 3 and 4 can be replaced by a much more efficient 1-step anti-solvent crystallization phase. White sugar can be derived directly from the crude juice, avoiding the necessity of the environmentally demanding carbonatation step while lowering the energy costs for water evaporation. Since the viscosity of the anti-solvent/sugar/water mixture is much lower than a sugar/water mixture, the sugar crystals can be harvested without the need for energy intensive centrifugation. Besides, within the ProKris technology the anti-solvent can be recovered from the mixture and reused in the system. Overall, the Prokris system has three main advantages over the traditional process:

  1. It is a simple and very energy-efficient process, which
  2. Produces the same sugar quality at (much) lower cost and thus
  3. Creates a competitive small-scale solution to extract sugar from sugar beets or sugar-containing by-products.

Sustainability & greenhouse savings

According to research performed by the Wageningen University and Research (WUR), the energy consumption of Prokris technology is about 50% lower than traditional sugar refining processes. Besides the 50% energy reduction in the sugar refining process, about 90% less transport will be needed due to on-sight processing, causing not only a reduced distance travelled to the refinery but also a reduction in storage steps. Cutting the step of sugar beet to storage and then from storage to refinery will reduce transportation and energy costs dramatically. The savings obtained in reducing both energy and transportation costs added together results in a decrease of the carbon footprint by 1.5 million kg CO2 per ProKris unit compared to processing the beets in a traditional refinery.