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ISO/TR 27912:2016 — Carbon Dioxide Capture — Overview of Capture Technologies and Systems
A comprehensive technical review of CO₂ capture technologies covering post-combustion, pre-combustion, oxyfuel, and emerging approaches
Understanding ISO/TR 27912: A Comprehensive Review of CO₂ Capture Technologies
ISO/TR 27912:2016 provides a thorough technical overview of carbon dioxide (CO₂) capture technologies and systems, serving as a foundational reference for engineers, project developers, and policy makers working in carbon capture and storage (CCS). This Technical Report systematically categorizes and evaluates capture approaches across the full technology readiness spectrum, from commercially mature systems to emerging concepts. It establishes a common terminology and classification framework that underpins the entire ISO 279xx series on CO₂ capture, transportation, and geological storage.
ISO/TR 27912 emphasizes that no single CO₂ capture technology is universally optimal — the selection depends critically on the emission source characteristics (concentration, pressure, scale), available utility infrastructure, and integration requirements with existing industrial processes.
The standard classifies capture technologies into three main routes: post-combustion capture, pre-combustion capture, and oxyfuel combustion. Post-combustion capture, typically using chemical absorption with amine solvents, is the most mature approach and can be retrofitted to existing power plants and industrial facilities. Pre-combustion capture, applied in integrated gasification combined cycle (IGCC) plants, removes CO₂ before combustion, yielding a hydrogen-rich fuel. Oxyfuel combustion uses nearly pure oxygen instead of air, producing a flue gas with highly concentrated CO₂ that requires minimal purification.
Technology Comparison and Performance Metrics
ISO/TR 27912 provides detailed performance data for each technology pathway, including energy penalty, capture efficiency, solvent consumption, and capital cost indicators. The energy penalty — the reduction in net power output due to capture — ranges from 8-12% for advanced pre-combustion systems to 25-40% for first-generation post-combustion amine scrubbing, representing the single most important technical challenge facing CCS deployment.
| Technology Route | Capture Efficiency | Energy Penalty (%) | Maturity (TRL) | Key Applications |
|---|---|---|---|---|
| Post-combustion (amine) | 85-95% | 25-40 | TRL 8-9 | Power plants, cement, steel |
| Post-combustion (membrane) | 70-85% | 15-25 | TRL 5-7 | Natural gas processing |
| Pre-combustion (Selexol) | 85-95% | 8-15 | TRL 7-8 | IGCC, hydrogen production |
| Pre-combustion (PSA) | 75-90% | 10-18 | TRL 6-8 | Industrial hydrogen |
| Oxyfuel combustion | 90-98% | 18-28 | TRL 6-7 | New-build power plants |
| Chemical looping | 90-99% | 10-20 | TRL 4-6 | Power, hydrogen |
The energy penalty of CO₂ capture is not a fixed value — it depends strongly on the CO₂ concentration in the source gas. For low-concentration streams like gas turbine exhaust (3-4% CO₂), the energy penalty can exceed 40%, while for high-concentration streams like ethanol fermentation (nearly 100% CO₂), capture energy is negligible.
The standard also addresses solvent degradation and environmental emissions, a critical operational concern for amine-based systems. Solvent losses through degradation (thermal and oxidative) and volatile emissions (amines, ammonia, nitrosamines) require careful management through solvent selection, continuous reclaiming, and emission control systems. Advanced solvents such as hindered amines, piperazine, and blended amine formulations have been developed to address these challenges, offering 20-40% lower energy requirements and significantly reduced degradation rates.
Engineering Design Insights for Capture System Integration
ISO/TR 27912 offers crucial engineering guidance on integrating capture systems with existing industrial processes. The most significant design consideration is the heat integration strategy — the capture process, particularly solvent regeneration in amine scrubbing, requires substantial thermal energy at specific temperature levels. Proper integration with the steam cycle can reduce the net efficiency penalty by 5-10 percentage points compared to standalone capture.
A second critical insight is the management of flue gas impurities prior to capture. SOx, NOx, particulates, and trace metals can severely impact solvent performance and longevity. The standard recommends upstream polishing to reduce SO₂ below 10 ppmv and particulate loading below 5 mg/Nm³ to maintain acceptable solvent performance and minimize waste generation.
Modern capture plant designs based on the principles in ISO/TR 27912 have demonstrated capture costs below $50/tCO₂ for natural gas processing and under $70/tCO₂ for large-scale power plant applications, approaching the cost levels needed for widespread commercial deployment without strong policy support.
Frequently Asked Questions
Q: What is the most cost-effective CO₂ capture technology according to ISO/TR 27912?
A: The standard does not designate a single “best” technology. For retrofitting existing power plants, post-combustion amine scrubbing is the most proven option. For new-build facilities, pre-combustion capture (IGCC) or oxyfuel combustion may offer lower long-term costs. The optimal choice depends on site-specific factors including fuel type, plant size, CO₂ transport distance, and regulatory environment.
A: The standard does not designate a single “best” technology. For retrofitting existing power plants, post-combustion amine scrubbing is the most proven option. For new-build facilities, pre-combustion capture (IGCC) or oxyfuel combustion may offer lower long-term costs. The optimal choice depends on site-specific factors including fuel type, plant size, CO₂ transport distance, and regulatory environment.
Q: How does ISO/TR 27912 address emerging capture technologies?
A: The standard provides a framework for classifying emerging technologies including chemical looping, calcium looping, cryogenic capture, and direct air capture (DAC). For each, it outlines the operating principles, current development status, and key technical barriers to commercialization.
A: The standard provides a framework for classifying emerging technologies including chemical looping, calcium looping, cryogenic capture, and direct air capture (DAC). For each, it outlines the operating principles, current development status, and key technical barriers to commercialization.
Q: What are the main environmental concerns with amine-based CO₂ capture?
A: The primary concerns are solvent degradation products (including ammonia and nitrosamines), solvent emissions to atmosphere, and increased water consumption. The standard recommends solvent emission monitoring, water wash systems, and reclaiming units to address these issues.
A: The primary concerns are solvent degradation products (including ammonia and nitrosamines), solvent emissions to atmosphere, and increased water consumption. The standard recommends solvent emission monitoring, water wash systems, and reclaiming units to address these issues.
Q: Can CO₂ capture be applied to all industrial emission sources?
A: In principle, yes, but the economics vary enormously. Sources with high CO₂ concentration (cement kilns: 20-30%, natural gas processing: 5-15%) are most favorable. Low-concentration sources (gas turbines: 3-4%) face higher capture costs and energy penalties.
A: In principle, yes, but the economics vary enormously. Sources with high CO₂ concentration (cement kilns: 20-30%, natural gas processing: 5-15%) are most favorable. Low-concentration sources (gas turbines: 3-4%) face higher capture costs and energy penalties.
