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Innovative examples of energy efficiency in the German sugar industry - dewatering and drying process for sugar beet p

Energy Efficiency in IPPC installations, 21.-22. October 2004 in Vienna Austria Trend Parkhotel Schönbrunn. Dipl.-Ing. Christian Voß. Dr.- Ing. Joachim Wieting. Südzucker AG for the German Association of Sugar Industry. U MWELT B UNDES A MT , Berlin.

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Innovative examples of energy efficiency in the German sugar industry - dewatering and drying process for sugar beet p

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  1. Energy Efficiency in IPPC installations, 21.-22. October 2004 in Vienna Austria Trend Parkhotel Schönbrunn Dipl.-Ing. Christian Voß Dr.- Ing. Joachim Wieting Südzucker AG for the German Association of Sugar Industry UMWELT BUNDES AMT, Berlin Postfach 33 00 22, D-14191 Berlin Tel. 030/ 8903-2829 joachim.wieting@uba.de Werk Warburg, D-34414 Warburg Tel. 05641/ 9413 Christian.Voss@Suedzucker.de Innovative examples of energy efficiency in the German sugar industry - dewatering and drying process for sugar beet pulp -

  2. Structure 1. Introduction (targets and development of the specific energy requirement) 2. Mechanical dewatering process for sugar beet pulps in the sugar industry as regards energy 3. Drying processes (drum drying, low temperature drying and evaporation drying) 4. Energy aspects of pulp drying 5. Comparison of energy consumption and the economics of different types of installations with examples 6. Characterisation of the technology – economic and ecological aspects

  3. Background and Motivation With the finalisation of the Council Directive 96/61/EC concerning „Integrated pollution prevention and control“, the so-called „IPPC Directive“, the concept of an integrated approach to reduce environmental pollution is being pursued at European Community level for the first time, with all installations covered by the directive now requiring permits. The EU Commission is supporting the implementation of the directive as part of its exchange of information by having leaflets compiled on the „best available techniques (BAT)“ by the European Integrated Pollution Prevention and Control (IPPC) Bureau in Sevilla, Spain.

  4. Background and Motivation • The „food, drink and milk“ BREF gives information at community level on the best available techniques in the sugar industry to help promote the use of these techniques and to support the member countries effectively in their efforts to protect the environment. • The efficient use of energy in the industry helps avoid and/or control emissions in the air, in water and in the ground as far as possible. • The formulation of the directive into a new VDI guideline in Germany will set out primary and secondary control measures and new reduced emission figures for production technology.

  5. Introduction precautions in the interest of the climate • Agreement between German sugar industryand thegovernment board signed on 19.12.2000: • Reduction of the specific CO2 emissions of 41 – 45 % by 2005/06 Base year 1990: CO2 emissions/beet 148 kg/t Target year 2005/06: 81 – 87 kg/t achieved 2000/01: 84 kg/t with 288.5 kWh/ton of beet Target achievement:almost 100 %

  6. Introduction Specific energy consumption in the German sugar industry kWh / 100 kg beets 125 100 75 current 1996: 50 30,6 ABL DDR / NBL 25 basis 1990: D, ges target 2005 : 35,6 29 0 1950 1960 1970 1980 1990 2000 2010 year ABL = old Federal states NBL = new Federal states D = Germany as a whole

  7. Introduction Specific energy consumption in the German sugar industry Since 1990 > 300 Million € have been invested in projects for combined heat and power generation (CHP). Degree of efficiency of heat and power combinations > 90 % re-use of the heat several times normalf = 7 – 8 Future: physical limits increasing technical expenditure (costs) marginal energy savings ______________________________________________________ Personal remarks on sugar market regulation

  8. Introduction Energy conversion in a beet sugar factory and VDI extra edition 2594 • Main flows of energy and technical processes are more closely interlinked than in any other sector of industry. • Amount of energy used Sugar production : Dried pulp production 2 : 1 • VDI-Guideline 2594 „Emission reduction in pulp drying plants in the sugar industry“, First printed August 2004

  9. Energy aspects of the dewatering process for beet cossettes Production of dried pulp with 90 % dry substance and 10 % water from extracted cossettes with 10 (- 14) % dry substance and 90 % water in 2 dewatering stages: mechanical thermal Amount of energy used kWh/t water approx. 30 approx. 3.000 1 : 100 Target: To remove as much water as possible mechanically.

  10. Energy aspects of the dewatering process for beet cossettes State of the art: Spindle presses horizontal/vertical

  11. Energy aspects of dewatering process for beet cossettes Quantity of material pressed out depends on capacity of presses - Hardening with calcium ions (gypsum), Development by Südzucker (SZ): 34 3,4 32 3,2 30 3 28 2,8 Water carrying in kg Water/ kg Dry-substance content Dry-substance content in Press-pulps in % 26 2,6 24 2,4 22 2,2 20 2 80 82 84 86 88 90 92 94 96 98 00 02 Campaign Dry-substance content in % Watercarying in kg Water/kg Dry-substance content SZ-Pressing target before drying: 32.5 % dry substance in the pressed pulp

  12. Energy aspects of dewatering process for beet cossettes • Other mechanical dewatering processes % dry substance in the pressed pulp • Diffusive dewatering: 65 • in combination with evaporation plant to concentrate the press water • Disadvantage:  no suitable separation of solids/liquids • High-pressure, multi-layer pressing: 50 Filter band press: 300 bar; 15 min. pressing time Disadvantage:  no suitable filter cloth quality no reliable control of the 300 hydraulic • control loops • Extraction under alkaline conditions 45 – 50 • Pilot installations in France, Germany and England

  13. Energy aspects of dewatering process for beet cossettes • Combination of electroporation and alkaline extraction • Alkaline extraction results in increased deposits of calcium ions and thus to a definite increase in the pressability of the extracted cossettes- Dry substance (DS) content of extracted cossettes : 40 - 45 % (an increase of approx. 10 % DS) • Opening the cells by electroporation to prepare for deposit of calcium ions - opening the cell membranes by high voltage impulses • high voltage impulses: a voltage of several hundred kV for the duration of approx. 1 µsec • • lowenergy demand: approx. 1 kWh/t beet

  14. Energy aspects of dewatering process for beet cossettes • Changes in the mechanical properties of beet due to electroporation • Electroporation increases the flexibility of the cossettes considerably and enables them to stand up to heavier mechanical stress.

  15. Energy aspects of dewatering process for beet cossettes beets Possible configuration of electroporation and extraction * electroporation electroporated beets electroporated and alkalined cossettes slicing machine lime mash * patent applied for juice towards juice purification

  16. Drying process Steam system of a sugar factory with steam drying

  17. Drying process Steam system of a sugar factory with steam drying

  18. Energy aspects of cossettes drying In order to consider the energy aspects of the installations described, the general data of the factories with both direct and indirect dewatering systems have been standardised as follows: ·Beet processing 10.000 tons/day ·Length of „campaign“ (season) 90 days p.a. ·Mass flow ofpressed pulp: 160 kg/t beet processed = 66,7 tons/h ·Dry substance content of the pressed pulp 31 % ·Dry substance content of the dried pulp90 % ·Steam consumption of a sugar factory for200 kg/t processed beet = 83.4 t/h ·Live steam pressure 85 bar ·Live steam temperature 525 °C ·Thermal value of the fuel 40.195 kJ/kg .

  19. Energy aspects of cossettes drying ·Electrical energy demand of the sugar factory without drying 10.4 MW = 24.96 kWh/t beet processed ·Complete crystallisation of the thick juice in the beet campaign These norms pre-suppose that the factories have the following technical installations: ·A steam generator with85 bar and 525 °C. ·A corresponding back pressureturbine 3 bar back pressure to supply the evaporation station or 3 bar back pressure and 25 bar extraction pressure to supply the steam dryer. ·A gas turbine to reduce the use of electric energy when using asteam dryer. · A effluent treatment plant which can process the condensed vapours from the evaporation dryer. .

  20. Summary of the examples ofinstallations

  21. Summary of the examples of installations Additional energy costs in comparison to a factory without dryers for the individual variations: • High temperature dryers 1.581 103 € • Low/high temperature dryers 1.397 103 € • Steam dryers 268 103 € Operation related costs (higher investment costs of installations in comparison to lower fuel costs in operation) • High temperature dryers 388 103 € p.a. • Low/high temperature dryers 460 103 € p.a. • Steam dryers 554 103 € p.a.

  22. Summary of the examples of installations Investment costs plus net running costs of the dryer for the individual variations: • High temperature dryers 38.4 Mio. € • Low/high temperature dryers 40.7 Mio. € • Steam dryer 40.9 Mio. € Characterisation of the technology: At the present time steam drying is the best available technique for new sugar factory construction or for complete reconstruction of energy production and heat control systems. However, it cannot be integrated easily into a normal existing factory.

  23. Advantages achieved by steam drying Main achievement - Improvements for the environment with regard to emissions and energy consumption: • Emissions are avoided by direct primary use of energy for drying. • No application of steam-volatile and odorous vapours. • Energy consumption 30% less than in a factory with direct drying. Inter-media effects • Transfer of the exhaust fumes into the effluent (approx. 1.200 m3 effluent with a chemical oxygen requirement of 1.500 mg/l and a NH4-content of 25 mg/l).

  24. THANK YOU In conclusion we should like to thank all those who participated - the members of the VDI working group 2594, the participating companies in the Sugar Association and all of you for your attention. THANK YOU

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