Decarbonisation Technology May 2025 Issue

projects at small to medium scale (individual engine capture) and at low concentration. • Biomass combustion capture : Biomass boilers burning wood waste are commonly found at commercial greenhouse complexes and sawmills. Waste CO₂ can be captured using a Captivate carbon capture unit, with CO₂ used, for example, to enhance growth in greenhouses. • Geothermal applications : Some geothermal electricity generation plants emit non-condensable gases containing CO₂. MUF-16 has been demonstrated to successfully capture CO₂ among a mix of gases that even contain H₂S and mercury vapour. This challenging gas mixture has provided significant confidence about the longevity of the adsorbent under operational conditions. • Syngas : CO₂ is found in raw syngas produced by the steam reformation of methane (SMR). As such, there is a significant opportunity for the inclusion of economic carbon capture units in syngas operations. Air Products SMR process in Port Arthur, USA, uses a PVSA process and a solid-state sorbent to capture CO₂ at a rate of 60,000 m 3/hr. MUF-16 would be a suitable alternative adsorbent in this process and presents an exciting future business opportunity. The superior performance of MUF-16 lowers total costs in comparison to standard sorbents. Financial analysis Discounted cashflow economics using capital costs and energy consumption from commercially available small and medium- scale PSA carbon capture systems has been conducted. Low energy requirements lead to low operating costs and attractive internal rates of return, even at small scale and low concentration carbon capture. While not essential for compelling business cases, where available, tax credits, carbon taxes, and emission trading schemes can contribute to the revenue side of the equation. Future plans Captivate is now scaling up to design and construct pre-commercial demonstration units that have a capture capacity of approximately 1 tonne CO₂ per day, to provide the technical de-risking required to springboard into full commercial-scale operations. The small footprint

CO-lean stream

Emissions feed stream

CO-rich stream

Figure 3 Captivate Technology’s mobile demonstration unit

software to identify processes that deliver optimal purity, recovery, productivity, and lowest energy consumption when using MUF-16. For example, a simple four-step process can deliver methane with up to 99% recovery and up to 99% purity from raw biogas. Analysis has also been conducted to capture methane from post-membrane tail gas, which has a CH₄/CO₂ ratio = 6/94. A two-step VPSA process can recover high-quality methane from this tail gas. • Cement process emissions capture : The cement industry accounts for approximately 8% of global CO₂ emissions. Emissions occur in the manufacture of clinker, which is an initial step in making cement. CO₂ emissions occur from the kiln combustion of fuel and limestone (CaCO₃), which liberates CO₂. The CO₂ stream to be captured is, therefore, at a relatively high concentration (>20%), which provides favourable conditions for the use of MUF-16 on cement sites. The adsorbent has been tested at a cement plant in an early-stage duration test, and results showed it to be a very suitable for removing CO₂ from cement emissions. • Natural gas post-combustion capture : Natural gas engines, boilers, and turbines are abundant in industry for power and electricity generation and process heat. MUF-16, as shown in Table 1, has been demonstrated to be effective in capturing CO₂ from these emissions. The CO₂ concentration in the emission stream can vary from 3% in gas turbines to close to 10% in boilers. With its favourable properties, the adsorbent can be used for economic