By Martin Coulthard , Rajib Roy and Jakub Marczyk , James Walker |
Fig 1 : Pressure-temperature phase chart for CO2 . |
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Authors Martin Coulthard , Group Manager – Gaskets , Rotabolt & Compression Packing Rajib Roy , Product Manager Jakub Marczyk , Product Director www . jameswalker . biz |
As the demand for carbon capture , utilisation and storage ( CCUS ) technology continues to grow , the need for effective and reliable sealing solutions in supercritical CO2 ( sCO2 ) applications has become increasingly important . Among these sealing solutions , compression packing plays a pivotal role , particularly in valve stem sealing applications where the integrity of the seal is paramount for both operational efficiency and environmental safety . sCO2 presents unique challenges , including high pressures , variable temperatures and the potential for chemical interactions with sealing materials . Therefore , selecting appropriate compression packing materials and designs is essential to ensure long-term performance and reliability in these demanding environments . CCUS is gaining significant popularity due to its crucial role in helping achieve carbon emission reduction targets . To meet the global Net Zero CO2 emissions goal by 2050 and the 1.5 ° C limit set by the Paris Agreement , investment in CCUS projects is growing rapidly and is expected to continue doing so . This article examines the sealing challenges faced in CCUS and James Walker ’ s commitment to meeting these as part of its own drive for sustainability and environmental protection . |
Sealing challenges in supercritical CO2 applications
CO2 exists in multiple phases — gaseous , liquid , and supercritical — depending on the temperature and pressure in application . These phase transitions present unique challenges for the materials used in CCUS systems . CO2 enters a supercritical state at relatively modest conditions ( around 31 ° C and 74 bar , or 1070 PSI ), and in this state , it displays characteristics of both a liquid and a gas . This supercritical phase is particularly advantageous for transport and storage of CO2 due to its high density , but it also poses significant challenges for the materials used in pipelines , compressors , and valves . Compression packing serves as a versatile sealing mechanism , providing flexibility and adaptability across various applications . However , its performance in sCO2 environments requires careful consideration of material compatibility , thermal stability , and mechanical properties . Materials such as PTFE ( polytetrafluoroethylene ) and other advanced polymers are currently being evaluated for their ability to withstand the specific conditions presented by sCO2 , including the effects of pressure and solvent characteristics .
High-performance fugitive emissions control
When evaluating packing systems for sealing in supercritical CO2 ( sCO2 ), several critical factors
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