Innovators at the NASA Johnson Space Center, in collaboration with Jacobs Technology, have developed a reliable, efficient, and cost-effective carbon dioxide (CO2) removal and dehumidification system. The Liquid Sorbent Carbon Dioxide Removal System was designed as an alternative to the current CO2 removal technology used on the International Space Station (ISS), which uses solid zeolite media that is prone to dusting, has a low absorption capacity, and requires high regeneration temperatures and frequent maintenance.
Motivated by CO2 removal systems on submarines, NASA innovators began investigating the use of liquid sorbents. Liquid sorbents have a capacity four times greater than solid zeolites, require low regeneration temperature, and need fewer unreliable moving mechanical parts than solid-based systems.
While submarine CO2 scrubbers spray an adsorbing chemical directly into the air stream and allow the liquid to settle, the new system is designed for ventilation applications and utilizes a gentle, passive, and direct air/liquid contactor. The contactor is composed of a bifurcating manifold with 3D-printed corrugated walls that contain capillary channels onto which thin films of liquid sorbent are deployed. The liquid is held in place by surface tension and capillary forces. As the liquid is exposed to the air, it absorbs carbon dioxide and humidity from the environment.
NASA’s new CO2 removal system has significant advantages over current CO2scrubbers; for example, the new system eliminates the need for large blowers and compressors that force air at high velocities through adsorption-based systems using solid sorbents. The Liquid Sorbent Carbon Dioxide Removal System is robust and reliable, while being low in weight, volume, and power requirements. The system is capable of reaching equilibrium when the liquid sorbent surface is being regenerated at a rate equal to the rate of absorption into the liquid.