Liquid Sorbent Carbon Dioxide Removal System

mechanical and fluid systems
Liquid Sorbent Carbon Dioxide Removal System (MSC-TOPS-84)
Using a 3D-Printed Capillary Microchannel Contactor
Overview
Innovators at the NASA Johnson Space Center (JSC), in collaboration with Jacobs Technology, and IRPI, have developed a reliable, efficient, and cost-effective carbon dioxide (CO2) removal and dehumidification system. 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 CO2 scrubbers. 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 Technology
NASA's 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, NASA's new system uses a capillary driven 3D printed microchannel direct air/liquid contactor in a closed loop system. 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.
ISS as seen by STS-124; Photo Credit: NASA on the Commons, https://www.flickr.com/photos/nasacommons/35201127816/in/album-72157648186433655/ Figure 1: 3D Printed microchannel air/liquid contactor; Figure 2: (a) Isometric top view of contactor; (b) Close up view of microchannels; (c) Cross- section of contacting surface
Benefits
  • Enables simplified system integration: Does not require large blowers and compressors that need to force air at high velocities through typical CO2 removal systems
  • Offers a reliable, efficient design: Requires fewer moving mechanical parts than solid based systems and offers low weight, volume, and power requirements
  • Presents improvements over current technologies: Liquid sorbents have favorable capacity, up to four times greater than current solid zeolites
  • Facilitates simple regeneration techniques: Liquid sorbents have low regeneration temperatures, so the materials do not need to be heated to extreme temperature

Applications
  • Aerospace
  • Agriculture: Controlled Atmosphere Storage
  • Automotive: Recirculating Air Conditioning Systems
  • Chemical Manufacturing
  • Commercial Space Flight
  • Consumer Goods: Rebreathers for Scuba Diving
  • First Responders: Rebreather Systems
  • Marine: Submarines and Submersible Craft
Technology Details

mechanical and fluid systems
MSC-TOPS-84
MSC-26442-1
11,058,990
"Liquid Behavior through a Capillary Microchannel Contactor in a Reduced Gravity Aircraft," Tanya Rogers, John Graf & Julia Worrell, 07/16/2017,
https://ttu-ir.tdl.org/handle/2346/72942
Similar Results
front
Air Revitalization for Vacuum Environments
The NASA life support system uses a regenerable vacuum swing adsorption process, known as Sorbent-Based Air Revitalization (SBAR), to separate water and carbon dioxide for disposal. The SBAR system is an adsorbent-based swing bed system that has been optimized to provide both humidity and carbon dioxide control for a spacecraft cabin atmosphere. The system comprises composite silica gel and zeolite-packed beds for adsorption and a bypass system for flow control. Under normal operating conditions, the disposal system would require a high-quality vacuum environment to operate. Improvements to the SBAR system include an enhanced inherent capacitance that extends the operation time within a non-vacuum environment for up to 4.5 hours. Flight time can be further expanded with multiple SBAR systems to allow for system regeneration. By scheduling periodic thermal regenerations&#151nominally during sleep periods&#151the SBAR technology may be suitable for missions of unlimited duration.
NEW CFC Front Image
Cryogenic Flux Capacitor
Storage and transfer of fluid commodities such as oxygen, hydrogen, natural gas, nitrogen, argon, etc. is an absolute necessity in virtually every industry on Earth. These fluids are typically contained in one of two ways; as low pressure, cryogenic liquids, or as a high pressure gases. Energy storage is not useful unless the energy can be practically obtained ("un-stored") as needed. Here the goal is to store as many fluid molecules as possible in the smallest, lightest weight volume possible; and to supply ("un-store") those molecules on demand as needed in the end-use application. The CFC concept addresses this dual storage/usage problem with an elegant charging/discharging design approach. The CFC's packaging is ingeniously designed, tightly packing aerogel composite materials within a container allows for a greater amount of storage media to be packed densely and strategically. An integrated conductive membrane also acts as a highly effective heat exchanger that easily distributes heat through the entire container to discharge the CFC quickly, it can also be interfaced to a cooling source for convenient system charging; this feature also allows the fluid to easily saturate the container for fast charging. Additionally, the unit can be charged either with cryogenic liquid or from an ambient temperature gas supply, depending on the desired manner of refrigeration. Finally, the heater integration system offers two promising methods, both of which have been fabricated and tested, to evenly distribute heat throughout the entire core, both axially and radially.
Filtering Molecules with Nanotube Technology
Filtering Molecules with Nanotube Technology
This water filtration innovation is an acoustically driven molecular sieve embedded with small-diameter carbon nanotubes. First, water enters the device and contacts the filter matrix, which can be made of polymer, ceramic, or metallic compounds. Carbon nanotubes within the matrix allow only water molecules to pass through, leaving behind any larger molecules and contaminants. The unique aspect of the technology is its use of acoustics to help drive water through the filter. An oscillator circuit attached to the filter matrix propagates acoustic vibration, further causing water molecules to de-bond and move through the filter. This use of acoustics also eliminates dependence on gravity (and thus filter orientation) to move water through the device. When water exiting the system diminishes to a pre-determined set point, a cleaning cycle is triggered to clear the sediment from the inlet of the filter, reestablishing the standard system flow rate. Unlike other filtration systems, flushing of the filter system is not required. The combination of acoustics and small-diameter carbon nanotubes in this innovation make it an effective and efficient means of producing contaminant-free, clean water.
Nuclear Power Plant
Carbon Dioxide Gas Sensors
Current bulk or thick film solid electrolyte CO2 sensors are expensive, difficult to batch fabricate, and large in size. In contrast, this new amperometric, solid-state, oxide-based electrolyte CO2 microsensor is affordable, easy to fabricate, and is so small that it could easily be integrated onto a substrate the size of a postage stamp. The basic composition of the sensor is identical to a previously designed NASA Glenn technology in which a solid electrolyte of Na3Zr2Si2PO12 is deposited between interdigitated electrodes on an alumina substrate and is covered by Na2CO3/BaCO3. Unlike its predecessor, however, this innovation includes an additional layer of nanocrystalline SnO2 sol gel, an electron donor type (N-type) semiconductor, on top of the Na2CO3/BaCO3 . This new layer provides a greater number of electrons for reduction reaction at the working electrode to detect CO2. As a result, overall performance is enhanced, and this new state-of-the-art sensor has the ability to operate at temperatures as low as 375°C. This low temperature capability significantly decreases the amount of power required to operate the sensor, opening the door to a multitude of new applications that were previously unattainable.
Eureka Pod
Portable Science Enclosure Features Unique Innovations
In the development of this technology for the ISS, engineers had to pay careful attention to electrical draw efficiency, ease-of-use, mass reduction, production cost, and safety, as conducting scientific research under spacecraft stressors is an important requirement. To create a controlled environment within the science enclosure, engineers designed a ventilation system incorporating an external fan/blower that pulls air across a HEPA filter and diffuses it in a manner that creates an even laminar flow within the enclosure before exiting through the exhaust filter. The glove seal forms an airtight and liquid impervious seal. This novel design also allows the user flexibility to choose their own task-specific glove material, facilitates easy tool-free assembly and quick glove changes, and may be transferable to other types of enclosures. Another key feature is that a through-port can be quickly fitted to an empty glove port. Due to the science enclosure system intended application aboard the ISS, its electrical draw does not exceed 24V, thereby making it feasible to power it from a battery for terrestrial field use or other applications where accessing power is a challenge. The combination of its performance, portability, BSL 2 capability, and inexpensive production costs could position the science enclosure system and accompanying innovations to be valuable in the fields of education, research, clean rooms, hospitals, and disaster relief efforts.
Stay up to date, follow NASA's Technology Transfer Program on:
facebook twitter linkedin youtube
Facebook Logo Twitter Logo Linkedin Logo Youtube Logo