Carbon dioxide (CO₂) emissions from power plants are conventionally captured by scrubber systems and stored for possible reuse or future underground sequestration. An economical scrubbing approach to curbing emissions An emissions control system is under development to derive oxalic acid from captured CO2. Source: Michigan Technological Universityand converting CO₂ into an industrially valuable commodity is being advanced by Michigan Technological University researchers.

An emissions control system is under development to derive oxalic acid from captured CO₂. The chemical produced can be used to extract rare earth elements from ore bodies, improve the economics of exploiting domestic resources and reduce dependence on China for rare earth imports.

The researchers installed the new scrubber design in a steam plant on the university’s campus. A sodium carbonate solution is injected at the top of the scrubbing column as flue gas is compressed through a filter that removes particles, then passes through a cooling unit before it enters the bottom of the column. The sodium carbonate removes CO₂ as the flue gas bubbles up the column in the pilot plant-scale system, reducing emissions from 8% to 4% CO₂.

In addition to efficient CO₂ removal, the scrubber design offers economic benefits to users. The use of sodium bicarbonate at a cost of $200 per ton represents a marked operating cost savings relative to the amines widely consumed for this application at $20,000 per ton.