The view that carbon capture, utilization and storage (CCUS) should form a key part of the global strategy for reaching net zero by 2050 is gaining traction. In March, the Intergovernmental Panel on Climate Change’s Sixth Assessment Report mentioned the need to transition to “very low or zero-carbon energy sources such as renewables or fossil fuels with CCS.”
In the UK’s Spring Budget, Chancellor Jeremy Hunt announced £20 billion for investment in CCUS infrastructure. The US Inflation Reduction Act increased the amount of CCUS tax credits from US$50 to US$85 per tonne of carbon removed, making the scheme accessible to a broader array of companies and investors. In the European Union, the emissions ‘cap and trade’ system (EU ETS) has seen carbon pricing exceed €100 a tonne for the first time.
Pollution is more expensive than ever before and globally, the push-pull factors of financial penalties and incentives are likely to see more industries investing in CCUS technologies. Yet forecasters say that more needs to be done. The International Energy Agency (IEA) calculates that the world will need nearly 1.3 billion tonnes of carbon capture capacity by 2030, against a projected volume of around 265 million tonnes.
Challenges of CCUS development
With increased CCUS project development – and more needed to achieve net zero goals – it is more important than ever to be aware of the challenges involved with capturing, processing, and storing carbon. At the core of CCUS development, the carbon capture step must be economical. However, point-source post-combustion carbon capture involves removing carbon dioxide from flue gases with large flow rates. These flue gases often contain high loadings of particulate contaminants, which can foul critical process equipment such as heat exchangers, reduce process efficiency over time, and cause solvent losses by emissions or accelerated degradation. Unfortunately, this directly translates to increased dollars per ton of carbon dioxide captured due to increased operating expenses.
Furthermore, once the carbon dioxide is captured, it must be either used or stored. Many of the industrial sites where carbon capture could be effectively used are not at geologically optimal locations for storage, meaning that key infrastructure, such as pipelines, is required to move captured carbon from industrial sites to storage facilities. Prior to transport, carbon dioxide is compressed to a dense phase to enable increased volumes of carbon dioxide to be transported.
Removing impurities in the carbon capture step with filtration and separation
As decarbonisation projects continue to accelerate, filtration and separation technology will play a critical role across the value chain of CCUS. This particularly applies to absorptive (solvent-based) carbon capture, which is currently the most used CCUS method.
Filters and separators are instrumental throughout the carbon capture value chain. On carbon capture system feed streams, filtration to remove solid contaminants from flue gases can prevent them from ever entering and fouling the system. These filters must have a long lifetime and remove fine contaminants from large gas flows with a limited pressure drop, so high-efficiency regenerable (self-cleaning) filters tailored to the application are recommended.
If the carbon capture system is a solvent loop, high-efficiency filters installed directly within the solvent loop on the lean side remove solid contaminants such as corrosion products and solids from flue gases that build up over time. Carbon-based filters are also recommended for removing organics and degradation products to limit foaming, and liquid/gas coalescers can be used to remove aerosol emissions from the absorber.
Compression and storage of carbon dioxide
The compression and storage of carbon dioxide is a key part of the CCUS process, with CO2 needing to be compressed into a dense phase to reduce its volume for efficient transportation and processing. As compressors are highly sensitive to contaminants, which can quickly cause corrosion, lowering compressor yields and increasing maintenance costs, it is vital to support them with the right technology.
High tech liquid/gas coalescers, for example, can be used to boost compressor operation and reliability by removing carry-over liquids (oil that seeps past the separator filter into the discharge piping), free water (condensation) and particulate matter (a mixture of solid and liquid droplets).
Once carbon dioxide is compressed, if the carbon dioxide is not purified to the right level when being transported - either for storage in geological reservoirs or for making new products - there is also a threat of corroding and plugging pipelines. Hydrates, solid compounds which form at high pressures when water is present, can cause significant damage due to pipeline plugging. Solid contaminants due to pipeline corrosion can also damage injection pumps or plug the reservoir, limiting the accessibility of carbon dioxide storage. Installing high efficiency particulate filters at the reservoir inlet is necessary to solve this issue. Fundamentally, proactive contaminant removal can provide a good return on investment.
It is evident that carbon capture will play an integral role in the wider energy transition and in helping the world fulfil its pledge under the Paris Agreement to limit global warming to 1.5 degrees below pre-industrial levels. While carbon capture technology has been around for decades, there needs to be a significant ramp-up in CCUS projects to meet climate targets by 2050.
International policies to boost in investment in CCUS schemes are a positive development but it is vital that finance is channelled appropriately. As well as new initiatives for CCUS zones and projects, consideration must be given to deploying the technology itself. Filtration and separation applications play a key role in maintaining high carbon capture efficiency and reliable equipment operation, as well as meeting safety regulations.
Collaboration is also going to be key as the world’s CCUS requirements will only be met if there is effective co-operation between tech suppliers, industry and governments across the globe.