Herstellung von Chemierohstoffen am Beispiel von 2,3 Butandiol aus. Rohstoffen

Transkript

1 Ökobilanzielle Bewertung der Herstellung von Chemierohstoffen am Beispiel von 2,3 Butandiol aus fossilen und nachwachsenden Rohstoffen H. Stichnothe, B. Bogunovic, A. Kuenz, U. Prüße

2 Introduction Background Reference system 2,3 BDO from fossil resources Model Data issues Environmental assessment Economic assessment Conclusion

3 Life Cycle Assessment (LCA) Goal Scope Inventory Impact assessment Interpretation Objective Product system Inventoy Impact Optimisation Comparison Systen boundary (cradle to gate) Functional unit (1 t 2,3 BDO respect. 1,3 BD) Inputs Energy & Materials) Outputs (Air, Water & Waste) CML Method

4 Reference system Assumption 2,3 BDO analog 1,3 PDO via epichorohydrin route Butene, mix Isobuten separation as MTBE Epichlorohydrinati on 2,3 BDO Destillation MEK and 1,2 BDO Hydolysis

5 P14: Raw material LCA model P13: Emissions T1: Production of Butenes T7: Production of methanol P2: Mixture of butenes P16: Raw material P11: MTBE P15: Methanol T8: Elimination of Isobutene as MTBE P32: Energy P17: Emissions P12: Mixture of 1- and 2-butenes P33: Raw material P40: Emissions P34: Energy T14: Heat generation from natural gas P41: Emissions P25: Water P35: Raw material T12: Electricity generation P4:Emissions P36: Energy P42: Emissions P9: Energy and additives T2: Chlorohydrination and epoxidation P37: Raw material T13: Production of sodium hydroxide P38: Energy P43: Emissions P39: Raw material T6: Production of chlorine P6: Mixture of buteneoxides P31: Energy P24: Water P28: Raw material P26: Emissions T10: Heat generation from natural gas P20: Emissions P29: Energy P27: Emissions P10: Energy T3: Hydrolysis P30: Raw material T11: Electricity generation P7: Mixture of butanedioles P23: Energy T9: Heat generation from natural gas P18: Heat P19: Methylethylketone P22: Raw material P5:1,2-butanediol T4: Destillation P8: 2,3-butanediol P21: Emissions

6 Plausibility test Cumulative energy GWP demand eco indicator 99 [kg CO 2 eq /t 2,3 [MJ eq q/t 2,3 [points/t 2,3 butanediol] butanediol] butanediol] 2,3 butanediol,, modelled ,3 butanediol, Klein ± ± ±30 1,4 butanediol, ecoinvent dataset Single impact Climate change Aggregated input Resource Aggregated Impacts Environment

7 Environmental impacts Eco points= Aggregated single score

8 Idealised process description Example of process route Field prep. Fertilisation Seeding Harvesting Renewables Wood Hydrolysis Filtration Evaporation Raw Glycerol Fermentation Agric. waste Hydrolysis Filtration Evaporation 1,3 BD Conversion 2,3-BDO Distillation Filtration

9 Idealised process description Assumptions for the process 120 g substrate 35 % sugar content 5genzyme Agric. waste Hydrolysis Filtration 960 g H 2 O 50 C, ph 6, 48 h 35 g solid residue, 5 g enzyme 42 g sugar 1000 g H 2 O ~ 42 g/l sugar Evaporation 790 g H 2 O 2 m 3 air 22 g 2,3-BD 0.5 g biomass 2 g salts 3 g EtOH Filtration 1 g glycerol Fermentation ti ~ 200 g/l sugar 6.5 g biomass 1 g salt 210 g H 2 O ~ 100 g/l 2,3 BD 30 C, no ph adjustment, 30h 9

10 Agric. Waste 1,3-Butanediene Product: 1,3-Butanediene Portion of process step Route 1 [%] Route 2 [%] Hydrolysis Evaporation Destillation Process heat Total Hot spot: Energy demand for removing water Problem climate change 10

11 Preliminary conclusion Agric. Waste 2,3-Butandiole 1,3 Butandiene Product: 2,3-Butandiole Portion of process step Hot spot: Energy demand for removing water Problem climate change Solution (?): () Adding sugar instead of removing water New questions: Sugar, thick juice or thin juice? Glucose, saccharose or? 11

12 Preliminary assumptions energy requirement for destillation Concentration Theoretically, Aspen, without Substrate after ferment. simplified compressor ASPEN with compressor [kg/m³) [GJ/t 2,3 BD produced] [GJ/t 2,3 BD produced] [GJ/t 2,3 BD produced] A ,13 22,7 6,97 B 50 53,95 61,9 14,6 C 80 31, , ,24

13 Flow sheet destillation provided by partner ph, esterification i

14 Data issues Economic assessment All provided data considered but partly huge variations, e.g. yeast /kg, Sum yeast, peptone, tryptone varies between kg/ t 2,3 BDO Energy price as suggested by industry for all feedstocks Environmental assessment Electricity for fermentation kwh/l broth Background data Ecoinvent v2.2, but some data missing and phosphate questionable

15 Results summarised Without credits for by products System Petrochemical A B C [kg SO2 Eq / 1 t 2,3 Acidification potential BD] 12,4 17,7 7,8 17 Global warming potential [kg CO2 Eq / 1 t 2,3 BD] Eutrophication potential [kg Nox Eq / 1 t 2,3 BD] 6,2 34,8 5,3 34 Human toxicity [kg 1,4 DCB Eq / 1 t potential 2,3 BD] Photochemical oxidation (summer smog) [kg Ethylen / 1 t 2,3 BD] 056 0, , , ,4 Stratospheric ozone depletion potential [kg CFC 11 / 1 t 2,3 BD] 0, , ,00 0,0004

16 Hotspots feedstock A Substrate[%] Destillation [%] Hot spots [%] Acidification potential Eutrophication potential Global warming potential Human toxicity potential

17 Hot spots feedstock B Electricity Ferm. [%] Destillation [%] Hot spots [%] Acidification Electricity Ferm. [%] Destillation [%] Hot spots [%] Acidification potential 37,17 43,55 80,73 potential Eutrophication potential 43,56 34,83 78,38 81 Global warming potential 45,23 36,98 82,21 Eutrophication Human toxicity yp potential 33,19 42,25 75,44 potential Global warming potential Human toxicity potential

18 Hot spots feedstock C Substrate [%] Electricity Ferm. [%] Destillation [%] Sum [%] Aidifi Acidification potential Eutrophication potential Global warming potential Human toxicity potential

19 Cost comparison just material and energy costs considered Energy costs Substrate costs Costs of inoculum Medium costs for fermentation ti Potential value of by Current costs products A [ /t 2,3 BD] [ /kg 2,3 BD] ,18 0, B [ /t 2,3 BD] [ /kg 2,3 BD] , ,54 0,44 0, C [ /t 2,3 BD] ,73 239, [ /kg 2,3 BD] , Petrochemical [ /kg 2,3 BD]

20 Life Cycle Assessment (LCA) Estimation of Environmental Impacts Assumptions Idealised process is used for the calculations Residues are considered as burden-free Capital goods are not considered Theoretical energy demand for heating and evaporation (simplified) Energy recovery rate of approx. 80% is assumed Only natural gas is used for steam production assuming a conversion efficiency of 89% Electricity and transport is currently not included System expansion is used (for by-products) 20

21 Preliminary results: GWP and EP (lab scale) 1t23b 2,3 butandiole from different feedstocks

22 Co products

23 Conclusion Hydrolysate as substitute rather than as single feedstock Agricultural production environmental impacts Residues energy demand 2,3 BDO conc. Without by product recovery, hardly any environmental benefit for bio based 2,3 BDO

24 Conclusion Medium is the most important cost driver, hence decisive for cost competetiveness By products have potential economic value increase competetiveness Demand for integrated processes rather than single product development Considerable data uncertainty/variation High uncertainty of (quantitative) results