Decarbonisation Technology - November 2023 Issue

Physical adsorption based

Chemical reaction based

Treated gas

AAG

Solvent pump

Solvent cooler

Sweet gas

LP recycle solvent

Lean solvent

Absorber

CO product

HP ash gas

Flash gas

Feed gas

Flash cooler

Sour gas

LP ash cooler

Flash compressor

Rich solvent

LP ash gas

Heat source

Rich solvent ash drum

Amine types

LP ash compressor

Secondary Amines: Diethanolamine (DEA) Methyldiethanolamine (MDEA) Diisopropanolamine (DIPA)

Primary Amines: Monoethanolamine (MEA) 2-amino-2-methyl-1-propanol (AMP) Diglycolamine (DGA)

HP ash drum

LP ash drum

Physical solvents

Propylene carbonate (Fluor process) N-methyl-2-pyrrolidone (Purisol process) Dimethyl ethers of polyethylene glycol (Selexol) N-formyl-morpholine and N-acetylmorpholine (Morphysorb) Rectisol

Cyclic Amines:

Tertiary Amines: Triethanolamine (TEA)

Piperazine (PZ) Morpholine

Figure 2 Chemical reaction and physical adsorption-based carbon capture

CO₂ emission reduction targets Scientists from around the world have

• Chemical reaction: amine, ammonia, sodium hydroxide (NaOH) or potassium hydroxide (KOH) • Physical adsorption • Solid adsorption • Membrane • Distillation – cryogenic or high pressure • Solid generation – refinery coker Solvent-based carbon capture Solvent-based carbon capture technologies are divided into chemical reaction and physical solvent systems. Chemical reaction-based systems employ a chemical to react with the CO₂. The reacted solvent is then regenerated, the CO₂ is released, and the regenerated solvent is reused. Physical solvent-based systems use a solvent that can physically adsorb the CO₂. The rich solvent is then regenerated, typically with pressure reduction and heat, to release the CO₂, and the regenerated solvent is reused. A simplified flow diagram of the two systems and a list of the typically used solvents are presented in Figure 2 . Solid adsorption-based carbon capture Solid adsorption carbon capture systems use a solid adsorbent to capture the CO₂ within the solid adsorbent. The solid adsorbent

determined target requirements to reduce the impact of CO₂ on the environment of the world, as listed below: • “To keep global warming to no more than 1.5°C – as called for in the Paris Agreement – emissions need to be reduced by 45% by 2030 and reach net zero by 2050.” (UN, 2022) • “The United States has set a goal to reach 100% carbon pollution-free electricity by 2035, which can be achieved through multiple cost- effective pathways, each resulting in meaningful emissions reductions in this decade.” (The White House, 2021) • “The NDC (Nationally Determined Contribution) sets an economy-wide target for the US to reduce its net greenhouse gas (GHG) emissions by 50-52% below 2005 levels in 2030.” (SDG Knowledge Hub, 2021) Understanding carbon capture technology Carbon capture is the removal of CO₂ from a stream, usually a vapour stream, by various technologies with the potential to recover the CO₂ in a usable form or to sequester the CO₂ for long-term storage. The primary CO2 capture systems are categorised as: • Solvent based