A Simulative Study and Economic Evaluation of Energy-Flexible Operation of an Electrified Batch Reactive Distillation

Laboratory of Reaction and Fluid Process Engineering A Simulative Study and Economic Evaluation of Energy-Flexible Operation of an Electrified Batch Reactive Distillation Thomas Grießer, Yannick Mayer, Erik von Harbou PEMT, Frankfurt, 10/11/2025 2Thomas Grießer ▪Chemical industry used 5.6 % of the electricity in EU27 in 2022[1] ▪Replacing fossil heating with electric heating ▪Replacing fossil feedstock with green feedstock https://www.pv-magazine.com/2022/07/04/german-consortiumplans-to-build-worlds-largest-heat-pump/ Motivation: Electrification of the Chemical Industry [1] https://cefic.org/a-pillar-of-the-european-economy/facts-andfigures-of-the-european-chemical-industry/energy-consumption/ H2O CH4 H2 −75 kJ mol −286 kJ mol 0kJ mol 3Thomas Grießer ▪Chemical industry used 5.6 % of the electricity in EU27 in 2022[1] ▪Replacing fossil heating with electric heating ▪Replacing fossil feedstock with green feedstock https://www.pv-magazine.com/2022/07/04/german-consortiumplans-to-build-worlds-largest-heat-pump/ Motivation: Electrification of the Chemical Industry [1] https://cefic.org/a-pillar-of-the-european-economy/facts-andfigures-of-the-european-chemical-industry/energy-consumption/ H2O CH4 H2 −75 kJ mol −286 kJ mol 0kJ mol „The chemical industry alone will quadruple its electricity demand as a result of electrification, moving away from fossil fuel-based energy generation and toward renewable electricity.“ Martin Brudermüller, Former BASF CEO, Opinion Piece in Handelsblatt , 12/13/2020 Motivation: Fluctuating Electricity Prices 4Thomas Grießer ▪Rapid expansion of electricity from intermittent renewables ➢Cheap but fluctuating ➢Minor seasonal ➢Daily/Weekly ➢Intraday Motivation: Fluctuating Electricity Prices 5Thomas Grießer ▪Rapid expansion of electricity from intermittent renewables ➢Cheap but fluctuating ➢Minor seasonal ➢Daily/Weekly ➢Intraday Adapt batch processes to avoid price peaks and exploit price throughs ➢Reduce energy cost 6Thomas Grießer Research Focus: Smart Batch Processes Research Goals: Flexibilize power consumption of batch processes to ▪lower electricity cost ▪enable grid stabilization by demand side management ▪avoid fossil sources from grid 7Thomas Grießer Flexibilization Strategies Flexibilization Variable Scheduling Batch 1 Batch 2 Time Engineering Effort Batch 1 Variable Operation Time Yannick Mayer Mo, 15:40 8Thomas Grießer Variable Process Operation | Concept Concept: Minimize electricity cost by adapting electricity consumption during operation to price Fig. 1: Example priceand conventional heating profile. Advantages ▪Drop-In-Solution for existing plants ▪Low investment cost Challenges ▪Flexibility limited by operational constraints ▪Influence on process conditions ➢Question: Is it worth investing in flexible plant? ➢Develop tool to estimate savings potential using real electricity prices 9Thomas Grießer ▪Esterification of citric acid with 1-butanol to tributyl-citrate (TBC): CA + 3 BuOH ⇆ TBC + 3 H2O ▪Distillation for removal of water byproduct from equilibrium to reach product yield ▪Reflow ratio Rfixed due to phase separator ▪Heat supply electrified: Example: Electrified Reactive Distillation Fig. 2: Flowsheet of electrified reactive distillation for TBC production. ➢largest power consumer Reduced Model for Optimization 16 Thomas Grießer Lower Limit Upper Limit Total Energy kW kW kWh Setup Lower Limit Upper Limit Total Energy kW kW kWh Energyand duty-based modeling approach ▪ ▪ Heat-up Distillation Finish Mixed-Integer-Linear-Problem Constraints ▪ ▪ ▪ ▪ Implementation of Optimization Problem in 17 Thomas Grießer [3] Parallelizing the dual revised simplex method, Q. Huangfu and J. A. J. Hall, Mathematical Programming Computation, 10 (1), 119-142, 2018. DOI: 10.1007/s12532-017-0130-5 Optimization Select optimal for every 15-min time slot Δtiwithin tbatch HiGHs.jl[3] Optimized Heating Profile, November 5th 2024 18 Thomas Grießer Results ▪Distillation at minimal to mitigate evening peak ▪9 % relative cost savings Scenario: Flexible single batch ▪Day-Ahead-Price-Profile for 5/11/2024 (DE-LU) ▪Starting Time always 6:00 AM ▪Maximum duration of 20.5 hours Fig. 8: Flexible heating profile and comparison of cumulative cost to conventional operation. Optimized Heating Profile, June 5th 2024 19 Thomas Grießer Scenario: Flexible single batch ▪Day-Ahead-Price-Profile for 2024 (DE-LU) ▪Starting Time always 06:00 am ▪Maximum duration of 20.5 hours Results ▪Process faster to avoid night ▪20 % relative cost savings ➢Optimization works as intended Fig. 9: Flexible heating profile and comparison of cumulative cost to conventional operation. Annual Savings 2024 –Conventional vs. Flexible Operation 20 Thomas Grießer 15 % Results ▪15 % savings annually ▪Achieved by 200 kW of flexible ➢~ 100 € savings per kW ➢Significant savings possible ➢Flexible model to assess further flexibilization strategies Scenario: 366 days of 1 batch day production in 2024 Fig. 10: Relative savings and cumulative cost for each day in 2024. 21 Thomas Grießer Summary •Decarbonization will increase electricity demand •Price volatility due to varying availability of Intermittent Renewables Variable Operation •Flexible operation as strategy to lower electricity cost •Developed reduced model to estimate savings potential for batch reactive distillation •Significant savings possible Thank you for the attention! Laboratory of Reaction and Fluid Process Engineering 23 Thomas Grießer Motivation: Electricity Market ▪Supply Chain disruptions and geopolitical tensions ➢Year-Ahead-Futures more expensive ➢Long-term contracts with local grid operators expensive / impossible ▪Rising share of Intermittent Renewable Electricity Sources (IRES) ➢Increasing volume on Spot-Market ➢Cheap but volatile Fig. 11: Comparison of average Electricity Prices by trading type for year 2024