Global Warming Potential (GWP) Estimation of IPA-Water Case Study
1. General Framework ¶ For any environmental impact metric i, the total life cycle assessment (LCA) is computed separately across three lifecycle phases: production, use-phase, and end-of-life, using the following general equations:
L C A i , p r o d u c t i o n = ∑ j L C I i , j , p r o d u c t i o n ∗ F l o w s j \color{red}{LCA_{i,production} = \sum_{j} LCI_{i,j,production} * Flows_j} L C A i , p ro d u c t i o n = j ∑ L C I i , j , p ro d u c t i o n ∗ Fl o w s j L C A i , u s e − p h a s e = ∑ k a l l L C A i , k , u s e − p h a s e + ∑ j L C A i , j , u s e − p h a s e \color{orange}{LCA_{i,use-phase} = \sum_{k_{all}} LCA_{i,k,use-phase} + \sum_{j} LCA_{i,j,use-phase}} L C A i , u se − p ha se = k a ll ∑ L C A i , k , u se − p ha se + j ∑ L C A i , j , u se − p ha se L C A i , E n d − o f − L i f e ( E o L ) − p h a s e = ∑ k a l l L C A i , k , E o L − p h a s e + ∑ j L C A i , j , E o L − p h a s e \color{green}{LCA_{i,End-of-Life(EoL)-phase} = \sum_{k_{all}} LCA_{i,k,EoL-phase} + \sum_{j} LCA_{i,j,EoL-phase}} L C A i , E n d − o f − L i f e ( E o L ) − p ha se = k a ll ∑ L C A i , k , E o L − p ha se + j ∑ L C A i , j , E o L − p ha se 2. Application To The IPA-Water Recovery Case Study ¶ For this case study:
The assessment includes the production phase (cradle-to-gate) and the IPA recovery process (gate-to-gate). Because IPA is recovered and reused rather than discarded, the end-of-life phase term does not apply here.
Therefore, the general framework narrows to:
G W P T o t a l = G W P P r o d u c t i o n − p h a s e + G W P U s e − p h a s e GWP_{Total} = GWP_{Production-phase} + GWP_{Use-phase} G W P T o t a l = G W P P ro d u c t i o n − p ha se + G W P U se − p ha se 2.1 Production Phase GWP ¶ To calculate this yourself, go to Module 2A: Production Phase Impact Prediction → Tutorial 1: Climate Change Impact Prediction Using ANN Model, select IPA as the chemical, and run the prediction to obtain its climate change (GWP) impact directly from the ANN model.
Chemical Impact (Production Phase, kg CO₂-eq/kg) Isopropanol Water Total
2.2 Use Phase GWP ¶ The recovery-phase GWP sums over k ∈ {distillation, pervaporation, each scaled from its own reference case through the power law}:
G W P n e w G W P r e f = ( F n e w F r e f ) α = ( E n e w E r e f ) β \frac{GWP_{new}}{GWP_{ref}} = (\frac{F_{new}}{F_{ref}})^\alpha = (\frac{E_{new}}{E_{ref}})^\beta G W P re f G W P n e w = ( F re f F n e w ) α = ( E re f E n e w ) β Technology Impact (Use Phase, kg CO₂-eq/kg) Distillation Pervaporation Total
2.3 Total GWP of IPA-Water Case Study ¶ G W P T o t a l = G W P P r o d u c t i o n − p h a s e + G W P U s e − p h a s e GWP_{Total} = GWP_{Production-phase} + GWP_{Use-phase} G W P T o t a l = G W P P ro d u c t i o n − p ha se + G W P U se − p ha se