Research Group ENVOC. Clean Technology: Sustainability Analysis through Exergetic Life Cycle Assessment. Prof. Dr. Ir. J. Dewulf

Transcription

1 Research Group ENVOC Clean Technology: Sustainability Analysis through Exergetic Life Cycle Assessment Prof. Dr. Ir. J. Dewulf EnVOC ENVIRONMENTAL ORGANIC CHEMISTRY & TECHNOLOGY RESEARCH GROUP

2 Clean Technology vs. Environmental Technology: - Environmental technology = end-of-pipe technology = clean up technology e.g. wastewater treatment plant - Clean technology = preventive approach through better design of the production process itself need for thorough process analysis thermodynamic analysis of process W Mass in Ex in Mass out Ex out Presentation at Universität Duisburg Essen June 2nd 2008 pag. 2

3 Research focus EnVOC Clean Technology Sustainable Development: Development which meets the needs of the present without compromising the ability of future generations to meet their own needs. Practical Approach: pag. 3 Brundtland definition Quantitative sustainability assessment of production processes based on second law thermodynamics (generation of entropy and loss of exergy)

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5 Key for cleaner processes: better resource use Resources= the motor for (clean) technology No resources, no economy... Sustainable resource management is necessary: - Limited availability - Growing population - Growing demand per capita - Economic importance - Geopolitical importance Need for a sustainable resource management tools

6 Critical issues in resource management

7 Guideline 1 in resource management: Look at the whole supply chain

8 Setting system boundaries... Hydrogen: clean fuel??? (Lapkin, 2006)

9 Guideline 2 in resource management: Make a fair allocation of all resources to the different products

10 Guideline 3 in resource management: No resource management without a proper quantification method

11 COWI Report for European Commission - DG Environment (March 2002): Concepts for Resource Management for a Sustainable Use of Resources Concepts Carrying capacity Physical measures Thermodynamics Economics-based Indicators Environmental Space Total Material Requirement Exergy Green GNP

12 What basis to be chosen for integrated resource mgt? Prof. Whitesides (Harvard) at Green Chem. Conf. (Washington, 2005): Sustainable technology development: If emissions are a bit under control: - Economically sound - Thermodynamically sound Idea: take thermodynamics as a base for resource management that enables: - Overall resource input assessment - Overall resource efficiency assessment

13 First law and Second law...

14 (W. Hermann, Stanford, 2007)

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20 But also stored resources: Energy: - fossil fuels (gas, oil, coal) - nuclear ores Materials: - Minerals - Metal ores

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22 2nd law of thermodynamics: all real processes generate entropy all real processes generate loss of work potential Entropy prod. Exergy in Resources Exergetic efficiency Waste Exergy out Product

23 Resource Exergy value or calculation method (Dewulf et al., 2008) Potential energy Kinetic energy Physical energy β in kj exergy /kj energy β = 1 β = 1 Ex = (h-t 0.s)- (h 0 -T 0.s 0 ) Chemical energy β = ~ 0.8 to 1.0, depending on composition Heat at temperature T Pressure of a gas Solar irradiation (whole spectrum) Nuclear energy Electricity Radiation β = 1-T 0 /T Ex = n. R.T 0 ln (P/P 0 ) β = β? 1 β = 1 β = 1 + (1/3).(T 0 /T) 4 (4/3).(T 0 /T)

24 Exergy analysis for resource management: - For a single process: exergy analysis - quantification of all inputs - quantification of all outputs - efficiency analysis: identification of opportunities - For a full supply chain: cumulative exergy analysis, exergetic life cycle analysis: - quantification of all resources out of the environment - fingerprint of the extracted resources - overall resource efficiency of supply chain

25 Exergy and ELCA analysis: - Main advantages: - universal - scientifically sound - one single scale for all type of energy ànd materials - allows straightforward allocation -Main limitations: - Allows resource assessment rather than emissions assessment - Not easy to communicate

26 Case studies at ENVOC-UGENT

27 Case 1: family dwelling - Optimization study of life cycle cost, energy consumption and pollution of a family dwelling - Data available from Flemish study: - Terraced house (average Belgian dimensions) - 3 construction types: - cavity wall - brick wall with external insulation - wooden frame construction

28 Total construction exergy (GJex) Exergy of construction materials production (building type averages) 600 Biomass Renewable energy flows (wind,...) Mineral aggregates 300 Minerals: metal ores 200 Minerals: non-metal ores 100 Nuclear ores 0 Cavity wall External insulation Wooden frame Organic non-renewable (oil, natural gas,...)

29 Exergy demand per year (GJex/yr) o Annual exergy consumption Internal heat gains 50 Heating 40 Installation components 30 Building activ ities 20 Transport to building site Cavity w all External insulation Wooden frame Construction materials (nonreusable) Construction materials (reusable) (De Meester, Dewulf et al., 2008)

30 Case 2: Waste gas treatment options - Biofiltration (BF) - 3 x 700 m 3-50% compost (v/v); 45% polystyrene (v/v) 5% CaCO 3 (v/v) - Activated Carbon adsorption (AC) - 4 units of 7 tonnes - Regeneration with steam - Catalytic Oxidation (CO) - Reactor of m 3 - CrO 3 catalyst on Al 2 O 3 support - Furnace gas use: 67 m 3 /hr - Thermal Oxidation (TO) - 6 heat recovery units of 15 tonnes ceramics - Furnace gas use: 191 m 3 /hr

31 CExC for construction and operation during 20 years (MJ) e.g. BIOFILTRATION Concrete 8.93 x 10 5 Rockwool 4.17 x 10 4 Glass 9.01 x 10 3 Steel 9.73 x 10 5 Steel, low alloyed 5.26 x 10 6 Steel, Zn coated 1.17 x 10 4 Reinforcement steel 1.38 x 10 6 Aluminium 1.25 x 10 3 Zinc 2.18 x 10 3 Copper 3.48 x 10 3 Limestone 1.71 x 10 5 Hydrogen 7.10 x 10 3 PE 5.14 x 10 5 PS 8.69 x 10 6 PES 6.21 x 10 4 PUR 1.37 x 10 4 PVC 1.64 x 10 4 Alkyl paint 8.23 x 10 3 Compost 2.06 x 10 7 Electricity 2.40 x 10 8 Car transport 6.49 x 10 3 Truck (28t) transport 4.91 x 10 5 River ship transport 7.88 x 10 6 Excavating by bulldozer 1.23 x 10 4 TOTAL : 2.87 x 10 8 MJ

32 (Dewulf et al., Sci. Tot. Environ., 2001) CExC per m 3 waste gas: BF : MJ AC : MJ CO : MJ TO : MJ Main consumption during operation - electricity - gas - steam = 83.6 to > 99.9 % - An end-of-pipe technology (clean-up) technology is in fact now a resource management issue - Best performance for BF mainly because operation at nearby ambient pressure and temperature - Exergy cost ~ Economic cost

33 Case 3: Pharmaceuticals In collaboration with Janssen Pharmaceutica - Emissions are under control - Feedstock is well known - Resource management: fuels ànd feedstock

34 OMe 1 2 Case study: Production of Tapentadol (analgesic) O Synthesis pathway: 1 HO OMe 2 S 3 S R N N N OMe OMe OMe R R N + S R N CRYSTALLIZATION R R N. HCl CHROMATOGRAPHY OMe R R N Tapentadol 6

35 The process level = alfa system boundary Example crystallization: Energy input Reactor Filter I Energy output Product input II III Product output Dryer Mother liquor tank

36 Operations Inputs Outputs At the reactor: Inerting 9.73 kg N 2 at 6 bar Pumping energy, 3300 kj Pumping in solution kg solution 6+7 Pumping energy, 4950 kj 6.99 kg N 2 at 6 bar Stirring at 80 rpm (continuous) Stirring energy, kj Heating up to 46 C kg Shellsol at 170 C Pumping energy 9000 kj Pumping in HCl in 2-propanol 197 kg HCl solution (6N) Pumping energy, 3300 kj 6.74 kg N 2 at 6 bar Cooling to 46 C kg Shellsol at -10 C Pumping energy, 9000 kj Adding seedling crystals kg 8 Stirring for 7 h Cooling to 40 C over 3h kg Shellsol at -10 C Cooling to 32 C over 3h Cooling to 22 C over 3h Stirring for 7 h Emptying reactor Cleaning reactor Pumping energy, kj kg Shellsol at -10 C Pumping energy, kj kg Shellsol at -10 C Pumping energy, kj 80kg water kg MeOH Pumping energy for water, 264 kj Pumping energy for MeOH, kj 7083 kg Shellsol at 170 C Pumping Shellsol, 4050 kj Stirring energy, kj 9.73 kg N kg Shellsol at C 6.99 kg N 2 at 46 C kg Shellsol at C kg Shellsol at C kg Shellsol at C kg Shellsol at C kg to filter 6.74 kg N 2 80 kg water liquid MeOH at 65 C 7083 kg Shellsol at C

37 KJ / mol RR Efficiency: Crystallization: 7.54 % Exergy losses: Chromatography: 5.15 % 1,80E+05 1,60E+05 1,40E+05 1,20E+05 1,00E+05 8,00E+04 6,00E+04 4,00E+04 2,00E+04 Reinigingssolvent Cleaning solvent Thermisch Thermal Elektromechanisch Elektromechanic Inert gas Chemicaliën Chemicals 0,00E+00 Crystallisation Kristallisatie Chromatography Chromatografie

38 Processes for energy and chemicals delivery Supporting processes for energy exchange Supporting processes for mass exchange γ system boundary (industry) β system boundary (plant) Natural resources CExC Production of 6/7 α system boundary (process) Crystallization or Chromatography 6 or 8 Basic chemicals manufacturing Hot shellsol production Solvent condensation Natural gas delivery Cold shellsol production Solvent destillation Electricity delivery Hot water production Waste gas scrubbing Electricity delivery

39 kj / mol RR Result gamma system boundary Efficiency: Crystallization: 1.25 % CExC: Chromatography: 1.00 % 1,00E+06 9,00E+05 8,00E+05 7,00E+05 6,00E+05 Aardgas Natural gas 5,00E+05 Electriciteit Electricity 4,00E+05 Chemicaliën Chemicals 3,00E+05 2,00E+05 1,00E+05 0,00E+00 Crystallisation Kristallisatie Chromatography Chromatografie (Dewulf et al., Green Chem., 2007)

40 Case 4: biofuels

41 Are biofuels the ultimate solution? At a first glance: Closing cycles = reduction in resource depletion and emissions

42 BUT: Modern agriculture: Pesticides & Fertilizer manufacturing Tractors & fuels Agricultural equipment Combines Maintenance & Spare parts

43 ..- and biofuel manufacturing

44 Fossil resources 15.4 GJ RESULTS: 1 ha rapeseed: GJ solar energy Agricult. machinery, Pesticides, Fertilizers... Emissions (CO 2,...) Electricity, Machines, Chemicals, GJ biodiesel Emissions (CO 2,...)

45 Step 1: Agricultural production Nutrients Pesticides Solar input Seeds Agriculture Fuels Straw Rapeseed

46 Step 2: Industrial biofuel production Rapeseed Fuel Transport Oil Steam Drying, Extraction, Refining Electricity Rape cake Rapeseed oil Methanol Esterification Hexane Fuel Glycerol RME

47 Agricultural Rapeseed Production: inputs and outputs related to 1 ha. All data are in GJ of exergy ha -1 yr ² Seed Solar radiation Pesticides ³ ³ Fertilizers Fuels Agriculture Rapeseed Straw

48 Agricultural Rapeseed Production: inputs and outputs related to 1 ha. All data are in GJ of exergy ha -1 yr Seed Solar radiation Pesticides Fertilizers Fuels Agriculture Rapeseed Straw

49 Efficiency (GJ biofuel/ha) : Corn > Rapeseed > Soybean

50 Input of non-renewables : Exergy (%) Cumulative Exergy (%) agricultural stage agricultural stage drying, cleaning and storage extraction and refining esterification 57 transport drying, cleaning and storage extraction and refining esterification transport

51 Overall RME production chain: inputs and outputs related to 1 ha. All data are in GJ of exergy ha -1 yr -1 Allocation of inputs to biofuels: Solar Irradiation Non-renewable 5.38 Agricultural 3.9 resources 1.80 Agriculture 62.1 Straw Rapeseeds 20.0 Non-renewable 5.26 Industrial 11.5 resources 3.04 Industrial conversion Meal Glycerol 47.5 RME

52 Case 5: fingerprinting energy In collaboration with - ETH, Zurich - eco-invent, Zurich & materials All natural resources (>100 types): grouped into 8 categories for fingerprinting

53 Fingerprinting energy resources 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Fossil energy Nuclear energy Biomass energy Wind energy Solar e. thermal Solar e. PV Hydro energy Minerals Metal ores Water Biomass Hydroenergy Wind, solar, geothermal energy Nuclear energy Fossil energy (Dewulf et al., Environ. Sci. Technol., 2007)

54 Fingerprinting materials 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Paper and Cardboards 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Fossil energy Plastics Nuclear energy Metals Biomass energy Chemicals organic Building materials Chemicals inorganic Wind energy Solar e. thermal Solar e. PV Glass Agricultural products Hydro energy ater treatment & supply Minerals Metal ores Water Biomass Hydroenergy Wind, solar, geothermal energy Nuclear energy Fossil energy Minerals Metal ores Water Biomass Hydroenergy Wind, solar, geothermal e Nuclear energy Fossil energy (Dewulf et al., Environ. Sci. Technol., 2007)

55 Ongoing projects - EU projects: Prosuite (FP 7), Eco²Chem (EFRD) - FWO: forest ecosystems - VLIR: anaerobic digestion in Cuba & Kenya - IWT: precious metal industry, pharma industry - MSc theses with biorefineries, -

56 Conclusions Good resource management will become more and more a central theme in developing sustainable technology Good resource management is aided by quantitative tools that need: - Overall chain consideration (system boundaries) - Proper allocation of resources to respective products - A proper (single) quantification unit

57 Exergy analysis meets these needs, allowing: - overall/integrated resource intake assessment - proper assessment of both energy ànd materials But also offers opportunities for - overall/integrated efficiency assessment - helps quantifying environmental sustainability: LCA & ELCA