Low energy packed tower and caustic recovery for direct capture of CO2 from air

• We used a 6.5 m tall packed tower prototype to study the capturing rate of CO2 from air. The tower was operated at a pressure drop of less than 27 pa in the packing at 0.7m/sec air speed with a counter current flow mode and with NaOH or KOH solution as the absorbent. The tower consumed an average of ~30 kJe per mole CO2. We found that via an intermittent operation with a 5% duty cycle, the fluid pumping work reduced by 90%. A novel process for removing carbonates ions from alkaline solutions based on titanate compounds is compared to the traditional lime cycle for the caustic recovery. The titanate process reduces the high-grade heat requirement by ~50%. The results from experimental data of leaching andprecipitation test support process design of the titanate cycle. In this paper, we also present the chemical process design.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik -- Kemiska processer (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering -- Chemical Process Engineering (hsv//eng)

Keyword

air capture

titanate

precipitation

packed tower

direct causticization

leaching

Publication and Content Type

art (subject category)

ref (subject category)