Combined Permeation of Pressurised CO2 and Impurities through Thermosets
Status: Project
Date Announced: April, 2023
Project reference: 35906
Summary
In applications for carbon capture and storage or enhanced oil recovery that include steel pipe remediation or lining, there is a need to assess the barrier performance of polymeric materials that are primarily thermosets. Specifically to establish their potential use as barrier layers to impurities in carbon dioxide (CO2) feedstock such as water vapour, ammonia, nitrous oxide, hydrogen and hydrogen sulfide. Generally the liner reduces the rate of arrival of corrosive species at the load bearing steel support wires or base pipe.
The CO2 fluid compositions may vary between locations and, potentially, there will be an enormous cost to the industry and an environmental impact of needing to expose thermoset systems to each fluid composition in a case by case approach to autoclave based ageing studies.
This study aims to establish whether some impurities are selectively blocked by the internal structure of the thermoset resin and so these can be excluded from screening studies for ageing in the future.
The chosen thermosets will be from the epoxide group, cross linked with aliphatic or aromatic amines, depending on the required glass transition temperature and mechanical properties. There will also be an interest in exploring options for epoxy formulations that contain flexibilizers in the form of additives or extended chain chemistries. TWI Ltd will work with the JIP sponsors and third party suppliers to acquire the material as appropriate for the JIP.
Project Concept
The project will use the established TWI permeation facility, supported by gas chromatographs, to measure over several months the rate of transport through thermosets of CO2 with water vapour and trace amounts of one of hydrogen sulphide, ammonia, nitrous oxide or hydrogen. It is expected that the concentrations of the impurities will be of the order of 500ppm. In any one permeation test, the pressures and temperatures of the CO2 feed can start in the gaseous phase and be pressurised to liquid at 500barg with the temperature altered above 31°C to create a supercritical fluid.
Where transport is detected, then the flux and permeability coefficients will be calculated for each species at each pressure and temperature step. This may allow the activation energy for permeation to be determined. Assuming that initial breakthrough is captured, then diffusion coefficients will be calculated at various temperatures with the potential to estimate the solubility and enthalpy of adsorption of each component.
Using this data, it is hoped that the expected transport levels at other pressure and temperature conditions can be estimated. The analysis of the thermoset will be for swelling, alteration in crystallinity, glass transition temperature, storage and loss modulus.
Objectives
- To establish the barrier performance of thermoset materials to CO2 with associated impurities.
- To establish if any transport of these impurity species causes ageing in the thermoset matrix.
Benefits
This work will provide guidance as to which generic CO2 composition with impurities are relevant to assess the barrier properties and ageing of thermosets.
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