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PBRE

Packed Bed Reactor Experiment (PBRE)

PBRE-WR Quad Chart
PBRE-WR Quad Chart
PBRE, PBRE-2 Quad Chart
PBRE, PBRE-2 Quad Chart

A critical unit operation used with many of the leading water reclamation and air revitalization technologies for advanced life support systems is the fixed packed bed reactor. Examples of systems currently under development or in use in space that take advantage of this type of reactor include the Volatile Removal Assembly (VRA), the Aqueous-Phase Catalytic Oxidation (APCO) system, the Microbial Check Valve (MCV), the Activated Carbon/Ion Exchange (ACTEX), and the IntraVenous Fluid GENeration (IVGEN) system. However, despite the many applications, there is very little understanding of how the reduced gravity environment affects the performance and reliability of the reactors. This is especially critical when the reactor involves simultaneous gas and liquid flows. The Packed Bed Reactor Experiment (PBRE) is designed to specifically resolve these technology gaps. The expected outcome of this research effort is to develop a set of guidelines and tools to enable engineers to reliably design and operate fixed packed bed reactors for microgravity as well as the lunar and Martian environments.

The PBRE ISS flight experiment will provide critical hydrodynamic information for a project which also includes reduced gravity aircraft and ground-based (1-g) testing. The main objective is to develop and validate macroscopic equations that can be used in partial and microgravity conditions to accurately predict flow pattern transitions; pressure drops; and chemical and biological transport rates in gas-liquid flows through randomly packed beds. The hydrodynamic investigations will focus on the transitions between flow regimes (i.e., bubbly-to-pulse flow transition) and the associated pressure gradients for each flow regime over the range of relevant test parameters (e.g., liquid flow rates, gas flow rates, and particle sizes). These design tools will provide important information for specific water reclamation and air revitalization technologies for advanced life support systems.

The PBRE is being developed under the Space Flight Systems Development and Operations Contract, through the collaboration of ZIN Technologies and the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC), the International Space Station (ISS), the University of Houston, the National Center for Space Exploration Research (NCSER) and NASA Johnson Space Center (JSC). The success of the PBRE project is crucial to the development of technologies which will maintain the well-being of crew members participating in extended space missions.

Recent Updates

Achievements for the week ending:

The Packed Bed Reactor Experiment – Water Recovery (PBRE-WR) completed a series of tests in the Microgravity Science Glovebox on the International Space Station.

Tests were performed on the International Space Station studying gas-liquid flows through Alumina packing. PBRE-WR was the fourth type of packing tested in the PBRE flow loop and was the first to test a realistic-type of packing (versus idealized packing better suited for modeling). Operation of the experiment was very successful over a three-week period, meeting all the science test objectives.

Test points completed included 312 different flow conditions at steady state; 133 test conditions to examine bubble removal strategies; 18 series of test conditions to examine the effects of hysteresis; and finally 63 test points at steady state with an extended time duration to examine slow accumulation of gas bubbles in the column.

PBRE-WR low flow
Image of PBRE-WR during low flow conditions. Bubbles and voids (darker spots) are captured using a high-speed video camera at 10 fps. They are measured to determine gas holdup during various test conditions. In this image, the liquid flow was 20 kg/hr and the gas flow was 100 gr/hr.

Packed Bed Reactor Experiment (PBRE-2) Operations Complete

The PBRE with the PBRE-2 test module installed has finished operations in the Microgravity Science Glovebox (MSG) facility on board the International Space Station. The PBRE Team wrapped up operations for the PBRE-2 test module from the Telescience Support Center at Glenn Research Center. The PBRE Team was able to complete testing of the PBRE-2 test module steady state flow conditions as specified in the PBRE-2 Test Matrix. The PBRE was removed from the MSG on September 18, 2020, and stowed. The PBRE-2 Science Team will now start analyzing the data. The PBRE, using the second test module PBRE-Water Recovery, is going to be scheduled to operate after several MSG payloads are conducted in the MSG.

Packed Bed Reactor Experiment (PBRE-2) Operations Continue.

The PBRE with the PBRE-2 test module installed is operating in the Microgravity Science Glovebox facility on board the International Space Station this week. The PBRE Team is sending commands and receiving data at the Telescience Support Center at Glenn Research Center. The PBRE-2 test column testing continues to progress well with over 1300 different flow conditions (test points) completed this week. This week of tests included working through the PBRE-2 test matrix with new test points with the addition of 24 test point re-runs of test points of special interest to the Science Team. The next series of tests will look at transient flow conditions. The Science Team is reviewing the data from the pressure drop from the Steady State Liquid Flush flow conditions. The PBRE-2 investigates the forces acting on and created by a gas and a liquid flowing simultaneously through a column filled with glass spheres in microgravity.

Packed Bed Reactor Experiment (PBRE-2) Operations

The PBRE with the PBRE-2 test module installed is operating in the Microgravity Science Glovebox facility on board the International Space Station this week. The PBRE on console team is working from the Telescience Support Center at Glenn Research Center. The testing continues to progress very well with over 450 different flow conditions (test points) completed. Three series of tests have been successfully completed which include 1) Startup (54 test points); 2) Steady State Liquid Flush (200 test points); and 3) Steady State Gas Flush (200 test points). The next series of tests will look at transient (non-steady) flow conditions. The Science Team focused this past week on reviewing pressure drop data from the “Steady State Liquid Flush” flow conditions. The data exhibits a behavior that seems to depend on the effective porosity (or fractional area available to flow) which was seen during the initial PBRE tests, but now appears to be confirmed. The PBRE-2 investigates the forces acting on and created by a gas and a liquid flowing simultaneously through a column filled with glass spheres in microgravity.

Packed Bed Reactor Experiment (PBRE) System Checkout This Week

The PBRE system with the PBRE-2 test module installed is working through the checkout and characterization of the liquid separator, flow system, and image system. The PBRE on console team is working from the Telescience Support Center at Glenn Research Center. The PBRE system checkout and characterization test are half way through the steady state liquid flush test points. Next the PBRE Team will perform the steady state gas flush test points and then the transient test points. The start of the PBRE-2 operations are scheduled to start after the completion of the checkout runs and then run operations for 3 weeks. The PBRE-2 test module operations will be conducted remotely by the PBRE Team though sending commands to run through the test matrix. The PBRE-2/Water Recovery (PBRE-2/WR) investigates the forces acting on and created by a gas and a liquid flowing simultaneously through a column filled with glass spheres in microgravity.

Packed Bed Reactor Experiment (PBRE) Runs Checkout Procedures This Week

PBRE Operations Team
PBRE operations team commanding the Packed Bed Reactor Experiment from the
Glenn Research Center Telescience Support Center

The PBRE-2 hardware was installed in the Microgravity Science Glovebox facility on board the International Space Station (ISS) by Chris Cassidy on August 12, 2020. The PBRE system with the PBRE-2 test module installed is in the process of the 1-week checkout and characterization of the flow system. The PBRE on console team is working from the Telescience Support Center at Glenn Research Center. The start of the PBRE-2 test matrix operations are scheduled to start next week and run for 3-weeks. When the PBRE-2 test module operations are complete, the ISS crew will exchange the PBRE-2 test module for the PBRE-Water Recovery (PBRE-WR) test module to repeat the process, 1-week of checkout and 3-weeks of operations. The PBRE-2/WR investigates the forces acting on and created by a gas and a liquid (water) flowing simultaneously through a column filled with glass spheres in microgravity. The PBRE-2/WR experiment allows the design of equipment for reactors, scrubbers, and other common chemical engineering units. The future equipment that this technology supports includes hardware for use in water recovery, planetary surface processing, and oxygen production.

Packed Bed Reactor Research Starts on the International Space Station

PBRE Installation on ISS
Chris Cassidy installing the Packed Bed Reactor Experiment into the Microgravity Science Glovebox on Space Station
The Packed Bed Reactor Experiment-2 (PBRE-2) hardware was installed in the Microgravity Science Glovebox facility on board the ISS by Chris Cassidy on August 12, 2020. The PBRE-2 test module will complete a 1-week checkout and then start the PBRE-2 test matrix operations and run for 3-weeks. When the PBRE-2 test module operations are complete, the ISS crew will exchange the PBRE-2 test module for the PBRE-Water Recovery (PBRE-WR) test module to repeat the process, 1-week of checkout and 3-weeks of operations. The PBRE-2/WR Experiment is commanded from the ground at the Glenn Research Center Telescience Support Center. The PBRE-2/WR investigates the forces acting on and created by a gas and a liquid (water) flowing simultaneously through a column filled with glass spheres in microgravity. The PBRE-2/WR allows the design of equipment for reactors, scrubbers, and other common chemical engineering units. For example, the future equipment that this technology supports includes hardware for use in water recovery, planetary surface processing, and oxygen production. The main objective of the Project is to develop and validate macroscopic equations that can be used in partial and microgravity conditions to accurately predict flow pattern transitions, pressure drops, and mass transfer rates in chemical and biological reactors in which gas-liquid flows occur through randomly packed beds.


Objective

• Investigate the role and effects of gravity on gas-liquid flow through porous media.

• Outcome will be the development of design and operational guidelines for gas-liquid Packed Bed Reactors in partial and microgravity conditions.

Relevance/Impact

• Directly aligns with high priorities from the NRC Decadal survey on Biological and Physical Sciences and crosses over to other technologies.

• AP-2: Provides a study of a critical multiphase flowcomponent for life support systems.

• TSES-6: Provides a fundamental study in porous media under microgravity conditions.

• Porous media are critical components in life support systems; thermal control devices; fuel cells; and biological and chemical reactors.

Development Approach

• Completed extensive (but time-limited) low-G aircraft tests.

• Engineering model hardware and Proto-flight unit.

• Video and data down-linked to the ground for evaluation.

• Develop on-orbit replaceable test section to extend experiment capabilities. Enables flexibility for future development of porous media components/devices.

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