Abstract
Carbon Capture, Utilization, and Storage (CCUS) is a critical pathway to achieving net-zero goals, with the industry poised for significant growth to meet these demands. Impurities in captured CO₂ can substantially affect the cost and efficiency of CCUS operations. A CO₂ specification defines the maximum permissible impurity levels in a CO₂ stream, ensuring the safety, reliability, and cost-effectiveness of CCUS processes from capture to storage [1].
Accurately estimating water content—i.e., the amount of water at the specified operating pressure and temperature—is essential for designing a dehydration unit. Understanding the water content in CO2 is crucial for ensuring safe transportation and loading/unloading processes to avoid water condensation or ice/gas hydrate formation that can lead to issues such as corrosion, and blockages. Water specifications vary greatly between projects (i.e. 30 ppm for Northern Lights [2]) and international standards (50 to 600 ppm [3]) with no clear consensus.
This paper introduces experimental equipment, methodologies, and new findings on the water content of carbon dioxide and impure carbon dioxide in equilibrium with ice, hydrate and liquid water. The study covers temperature ranges from the triple point to the critical point of carbon dioxide and pressures from 3 to 500 bar aiming to provide absolute water content values to avoid water condensation or ice/hydrate formation.
The experimental results are compared with predictions from two thermodynamic models: the Cubic-Plus-Association (CPA) equation of state and the Redlich-Kwong-Soave (RKS) equations of state with an advanced mixing rule. Hydrate formation conditions are modelled in all cases using the solid solution theory of van der Waals and Platteeuw and ice formation with a classical thermodynamic approach. Figure 1 shows some of the water content results for systems in equilibrium with liquid water (T=25°C) or gas hydrates (T=-30°C). These experimental data are used in turn to estimate the water specification across the full CCS chain (Figure 2). Further research will be carried out to understand the impact of other polar impurities such as amines, VOC and glycols.
Accurately estimating water content—i.e., the amount of water at the specified operating pressure and temperature—is essential for designing a dehydration unit. Understanding the water content in CO2 is crucial for ensuring safe transportation and loading/unloading processes to avoid water condensation or ice/gas hydrate formation that can lead to issues such as corrosion, and blockages. Water specifications vary greatly between projects (i.e. 30 ppm for Northern Lights [2]) and international standards (50 to 600 ppm [3]) with no clear consensus.
This paper introduces experimental equipment, methodologies, and new findings on the water content of carbon dioxide and impure carbon dioxide in equilibrium with ice, hydrate and liquid water. The study covers temperature ranges from the triple point to the critical point of carbon dioxide and pressures from 3 to 500 bar aiming to provide absolute water content values to avoid water condensation or ice/hydrate formation.
The experimental results are compared with predictions from two thermodynamic models: the Cubic-Plus-Association (CPA) equation of state and the Redlich-Kwong-Soave (RKS) equations of state with an advanced mixing rule. Hydrate formation conditions are modelled in all cases using the solid solution theory of van der Waals and Platteeuw and ice formation with a classical thermodynamic approach. Figure 1 shows some of the water content results for systems in equilibrium with liquid water (T=25°C) or gas hydrates (T=-30°C). These experimental data are used in turn to estimate the water specification across the full CCS chain (Figure 2). Further research will be carried out to understand the impact of other polar impurities such as amines, VOC and glycols.
| Original language | English |
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| Publication status | Published - 17 Jun 2025 |
| Event | 13th Trondheim CCS Conference 2025 - Trondheim, Trondheim, Norway Duration: 16 Jun 2025 → 19 Jun 2025 https://tccs.no/ |
Conference
| Conference | 13th Trondheim CCS Conference 2025 |
|---|---|
| Abbreviated title | TCCS-13 |
| Country/Territory | Norway |
| City | Trondheim |
| Period | 16/06/25 → 19/06/25 |
| Internet address |