ISO 27919-1:2018 — Post-Combustion CO2 Capture Performance Evaluation

1. Overview of ISO 27919-1:2018

ISO 27919-1:2018 specifies methods for measuring, evaluating, and reporting the performance of post-combustion CO2 capture (PCC) plants integrated with power plants. This standard, the first in the ISO 27919 series developed by ISO/TC 265, provides a common methodology for calculating key performance indicators (KPIs) for PCC systems based on chemical absorption using reactive liquids such as aqueous amine solutions, potassium carbonate solutions, and aqueous ammonia.

The standard covers thermal power plants burning carbonaceous fuels including coal, oil, natural gas, and biomass-derived fuels. It addresses both full-scale capture (treating the entire flue gas volume) and slip-stream configurations. The captured CO2 is processed through compression or liquefaction for subsequent transportation and geological storage.

2. System Boundary Definition

2.1 PCC Plant Integration

The standard establishes clear boundaries between the PCC plant, the host power plant, and auxiliary utilities. This boundary definition is critical because PCC operations are intimately integrated with power plant operations — steam is typically extracted from the power plant steam cycle for solvent regeneration, and electrical power is consumed by PCC equipment including pumps, fans, and compressors. The standard defines which energy and material flows cross the system boundary and how they should be accounted for in performance calculations.

2.2 Capture Efficiency and Product Quality

The standard defines capture efficiency as the ratio of CO2 captured to CO2 in the incoming flue gas. Typical PCC systems achieve capture efficiencies of 85-95%, although higher rates are technically feasible. The product CO2 stream must meet quality specifications for transportation and storage, including limits on moisture, oxygen, and other impurities that could affect pipeline integrity or storage operations.

3. Key Performance Indicators (KPIs)

3.1 Specific Thermal Energy Consumption

The specific thermal energy consumption (STEC) is the most important KPI for PCC plants, representing the thermal energy required to capture one unit mass of CO2. STEC is typically expressed in GJ per tonne of CO2 captured and depends on the solvent system, process configuration, and operating conditions. Amine-based systems typically have STEC values in the range of 2.5-4.0 GJ/tCO2, with ongoing research focused on reducing this energy penalty.

3.2 Specific Electrical Energy Consumption

The specific electrical energy consumption (SEC) accounts for electrical power used by PCC plant equipment including solvent circulation pumps, cooling water pumps, flue gas fans, and CO2 compression. The standard also defines the specific equivalent electrical energy consumption (SEEC), which combines thermal and electrical penalties into a single metric, enabling comparison of different PCC technologies on an equivalent basis.

3.3 Absorbent Consumption and Degradation

The specific absorbent consumption (SAC) quantifies solvent losses due to degradation, evaporation, and carryover. Amine degradation is a significant operational cost and environmental concern, as degradation products can be toxic and require treatment. The specific chemical consumption (SCC) accounts for additional chemicals used for solvent reclaiming, corrosion inhibition, and pH control.

4. Measurement and Instrumentation Requirements

ISO 27919-1:2018 provides detailed requirements for measurement methods and instrumentation. The standard classifies instruments based on their purpose and required accuracy, specifying calibration procedures and data collection protocols. Key measurements include flue gas composition (CO2, O2, H2O), product CO2 stream composition and flow rate, steam and condensate properties, cooling water parameters, and electrical power consumption. Measurement uncertainty must be quantified and reported to establish confidence in the calculated KPIs.

5. Engineering Insights for PCC Performance Evaluation

Key engineering considerations from ISO 27919-1:2018 include:

• The thermal energy penalty (STEC) represents the largest operating cost for PCC plants and the primary target for technology improvement.
• Performance evaluation must account for off-design conditions, including power plant load variations and ambient temperature effects on cooling system performance.
• Solvent management is critical — degradation products can cause corrosion, fouling, and increased emissions of volatile degradation compounds.
• CO2 compression typically accounts for 30-40% of the total electrical energy consumption, making compressor efficiency an important factor.
• The standard provides annexes with test principles, reference conditions, and calculation examples to support consistent implementation.

6. Frequently Asked Questions