Session: 14-02: Carbon Capture & Cleaner Fossil Fuel Technologies II

Paper Number: 163806

163806 - Enhancing Post-Combustion Carbon Capture Efficiency via Solvent Degradation Mitigation and Process Optimization 

Abstract: 

Amine-based post-combustion carbon capture (PCCC) systems, particularly those using monoethanolamine (MEA), remain a cornerstone technology for reducing CO₂ emissions from fossil fuel plants. However, operational inefficiencies stemming from solvent degradation pose significant challenges. In high-temperature environments or those with elevated oxygen concentrations, MEA undergoes oxidative, thermal, and carbamate polymerization degradation, forming heat-stable salts (HSS) and corrosive byproducts. These degradation pathways reduce solvent absorption capacity, increase corrosion rates, and necessitate frequent solvent replenishment, elevating operational costs by 15–30% in fossil-dependent power plants. While recent research prioritizes novel solvents (e.g., piperazine blends) or advanced materials (e.g., metal-organic frameworks), such solutions often require costly infrastructure upgrades, limiting their feasibility for emerging economies with entrenched fossil infrastructure. This study addresses this gap by optimizing conventional MEA systems through process-level modifications, offering a retrofittable strategy to enhance efficiency and reduce degradation without capital-intensive overhauls.↳ Focusing on natural gas-fired power plants in Egypt—a region prioritizing fossil energy amid rising temperatures and decarbonization pressures—this research integrates computational modeling (Aspen Plus v12) with pilot-scale experimentation. The simulation framework employs Rate-Based Distillation modules to model absorption/desorption dynamics under flue gas conditions typical of Egyptian plants (45–60°C, 8–12% CO₂, 3–5% O₂). Key degradation pathways were parameterized using kinetic data from literature, with validation against real flue gas compositions from the El Tebbin power station, which includes trace SOₓ and NOₓ. A factorial design evaluated three interventions: (1) oxygen scavengers (0.1–0.3 wt% sodium sulfite) to mitigate oxidative degradation; (2) pH stabilization (8.5–9.2) using sodium hydroxide to reduce thermal degradation and corrosion; and (3) intermittent solvent cooling during lean solvent recirculation to minimize thermal stress. Experimental validation involved 100-hour pilot trials using a bench-scale absorption/desorption unit, with continuous monitoring of CO₂ capture efficiency, solvent conductivity (to track HSS formation), and regeneration energy. Gas chromatography-mass spectrometry quantified degradation byproducts, including nitrosamines and organic acids. Results demonstrated that pH stabilization within 8.5–9.2 reduced amine oxidation by 19%, while intermittent cooling (achieving 5–7°C reductions at critical stages) lowered thermal degradation by 14%. Oxygen scavengers at 0.2 wt% reduced oxidative degradation by 22%, curtailing solvent replacement frequency by 15%. Collectively, these interventions boosted absorption efficiency by 12% (from 78% to 87% CO₂ capture) and reduced regeneration energy demand by 18%, primarily by decreasing steam requirements in the desorber. Economic analysis projected a 20% reduction in annual operating costs for a 500 MW plant, with minimal retrofitting expenses. The study underscores the viability of process optimization as a transitional strategy for fossil-reliant regions, aligning with net-zero timelines while preserving existing infrastructure. By prioritizing scalable adjustments over novel solvents, this approach offers emerging economies a pragmatic pathway to decarbonization. Future work will expand lifecycle assessments to compare emissions from optimized MEA systems against carbon-neutral alternatives, including the environmental impact of scavenger additives and energy trade-offs. Such insights will refine the role of retrofitted PCCC systems in global decarbonization portfolios, ensuring they complement—rather than compete with—long-term renewable energy transitions.

Presenting Author: Sharif Alsahbool The American University in Cairo

Presenting Author Biography: Sharif Alsahbool is a teaching assistant working with Dr. Essam Mohamed at The American University in Cairo (AUC), where he is pursuing an MSc in Sustainable Development (Green Technologies Concentration). He holds a BSc in Petroleum Engineering from Cairo University, which laid the foundation for his expertise in energy systems and sustainable resource management. With experience in program coordination, environmental advocacy, and international collaboration, Sharif has contributed to initiatives such as the UNLEASH Innovation Lab for SDGs and the COP29 Simulation Model. Fluent in Arabic and English, he is dedicated to bridging sustainable development theory with practical solutions to address global environmental challenges.