CO lean ue gas
CO lean ue gas
CO rich ue gas
CO lean ue gas
CO lean ue gas
CO lean amine
20% NaOH (aq)
CO lean methanol
CO lean solvent
CO rich ue gas
CO rich ue gas
CO rich ue gas
CO lean ue gas
CO rich solvent
CO rich methanol
Na CO (aq)
CO rich amine
Amine-wash rotating disk contactor
Amine-wash with tower contactor Absorption 3 GJft CO2
Absorption 1.4 GJft CO2 Methanol wash -40°C 25-70 bar g Up to 100% >98.5%
Mineralisation
Absorption 8.3 GJft CO2
Absorption Predominantly electrical power,
Separation principle Specific energy demand
with heat 40-60°C Ambient
<35°C Ambient 90% CO 2 mineralisation to Na 2 CO 3 1,000-75,000
40-60°C Ambient 90% >99%
Typical temperature Typical pressure Typical CO 2 removal Typical CO, purity
90% (target) 95% (target)
> 100,000,000
1,000-500,000
40,000-400,000
Typical plant size (tonnes per year CO 2 removal) Technology maturity level
Commercial, eg Linde Rectisol
Demonstration, eg SkyMine
Laboratory, eg ROTA- CAP from GTI &CCSL
Commercial from many suppliers
Figure 3 Absorption-based process for CO₂ capture from flue gases
On the other hand, those CO₂ emissions could be sequestered or utilised for e-fuel production. Until major emitters such as the Drax plant implement BECCS, there will be an ongoing debate about how ‘climate friendly’ large-scale biomass to energy really is. The good news is that Drax is planning to implement BECCS as part of the ambitious and visionary Zero Carbon Humber project. According to Drax, it aims to become a carbon-negative company by 2030. In its climate change proposal, it claims that BECCS at Drax could remove up to 8 million tonnes of CO₂ per year. This is around 40% of the BECCS with power needed to meet the UK Climate Change Committee’s Balanced Net Zero Pathway. Capturing CO₂ from the post-combustion flue gases is at the heart of BECCS. Carbon capture has been executed at scale using amine solvents, chilled ammonia, methanol, or potassium carbonate for decades. See Figure 3 for some process examples.
CO₂ removal from sour gas is an essential unit operation in upstream natural gas processing. Biomethane to biogas upgrades also rely on CO₂ removal using such technologies. CO₂ is also recovered from beer fermentation to provide gas to dispense the beer in pubs and restaurants, or to carbonate the beer when packaged into bottles or cans. The CO₂ captured by such processes can be of a very high purity after drying, liquefaction, and distillation. Achieving food-grade purity for use in beverage carbonation is possible. The capture of biogenic CO₂ using BECCS can yield a suitable high-quality feedstock for combination with hydrogen in synthetic e-fuels production. In the refining sector, carbon capture has been executed on the CO₂-rich process gas stream of steam methane reformers (SMR) at several refineries. The gases leaving the water-gas shift reactor and prior to the PSA hydrogen purification unit have a high CO₂ concentration
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