Decarbonisation Technology - February 2023

Location

A B

Post-combustion ue gas

Temperature

850 ˚C 250 ˚C 150 ˚C

Pressure 25 barg 1.4 barg 0.2 barg CO partial pressure 3.4 bara 0.6 bara 0.2 bara CO concentration* 15% 47% 20% H concentration* 76% 27% 0% N concentration* 1% 1% 62% CO concentration* 5% 15% 0% HO concentration* 0% 0% 17% CH concentration* 3% 10% 0% O concentration* *Molar 0% 0% 1%

Steam

Waste heat recovery

Heat

Fired heater

Steam

Water

PSA H purification

Natural gas feedstock

Water gas shift

Compressor

Hydrogen for desulphurisation

High temperature

Low temperature

Natural gas for burner

PSA tailgas

Burner air

Figure 5 Potential locations for CO 2 capture from steam methane reforming

carbon capture technologies because the CO 2 concentration and the pressure are both low. However, if a high overall CO 2 capture rate is required, the low-pressure post-combustion CO 2 emissions must be captured in addition to the high-pressure process CO 2 . An advantage of the Airovation mineralisation process is that it is rather agnostic to the CO 2 stream pressure, making it viable for use with the low-pressure post-combustion flue gas to achieve the highest overall capture rate. Carbon capture and mineralisation – putting captured CO 2 to good use Unlike the amine-based systems that require additional heat and natural gas or the VSA system that requires extra power at the carbon capture site, the Airovation Technologies CCM process avoids the need for additional utilities infrastructure at the CO 2 capture location. The idea of reacting the CO 2 in a liquid to form a new mineral chemical is core to CCM. The minerals produced can have a much higher value than the CO 2 gas recovered from traditional solvent absorption or alternative adsorption technologies. CCM is at the heart of the Airovation Technologies process for CO 2 sequestration. The minerals produced can be any one of the following: • Sodium carbonate (Na 2 CO 3 )

• Sodium bicarbonate (NaHCO 3 ) • Potassium carbonate (K 2 CO 3 ) • Potassium bicarbonate (KHCO 3 )

The CO 2-rich flue gas is reacted with sodium hydroxide (NaOH) or potassium hydroxide (KOH) alkali solutions to produce the sodium or potassium minerals, respectively. These alkalis are produced worldwide using chloralkali electrolysis either as the main product or as a by-product when chlorine gas or hydrogen chloride are the desired products. In any case, the feedstocks for the process are widely available and highly transportable (see Figure 6 ). Each of the mineral salts listed above has a breadth of applications. Sodium carbonate (Na 2 CO 3), or soda ash, is the 10th most widely used inorganic chemical in the world. Used extensively in flat glass and container glassmaking, it can comprise up to 30% of the glass melt feedstock by mass. This application for Na 2 CO 3 allows for circularity within the glassmaking process, and the glassmaker can avoid the transportation and procurement costs of high tonnages of soda ash. Potassium salt minerals are broadly known as potash. Potassium carbonate is used for glassmaking and producing soaps and detergents. Potassium bicarbonate is widely applied as a fertiliser, especially to neutralise acidic soils and simultaneously increase the potassium level.