Synthesis of Durable Zeolite 13X Insertion Coatings and Scaled-Up Experimental Demonstration for CO2 Capture

Author

Daniel Jamil Hocheimy, Florida Institute of TechnologyFollow

Date of Award

5-2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical and Civil Engineering

First Advisor

Darshan G. Pahinkar

Second Advisor

Hamidreza Najafi

Third Advisor

Toufiq Reza

Fourth Advisor

Ashok Pandit

Abstract

Minimizing the energy requirement for capturing carbon dioxide (CO₂) from post-combustion sources is critical to efficient industrial decarbonization and subsequent mitigation of the effects of climate change. The current portfolio of CO₂ capture technologies includes absorption, membrane separation and packed bed adsorption, which suffer from high energy and temperature requirements, scalability, and location dependency issues. Adsorption-based systems could cater to these concerns; however, their current embodiments primarily use packed adsorbent bed design and electricity-driven vacuum pumps to regenerate them. While simple and easy to fabricate, these designs are not scalable and cannot use heat to regenerate them because of the low thermal conductivity of the adsorbents and large adsorbent particle sizes (1 – 5 mm). Using adsorbent-coated microchannels has been shown to significantly enhance the performance of CO₂ capture systems due to excellent heat and mass transfer characteristics, resulting in rapid adsorbent regeneration using heat. However, methods to fabricate these channels are poorly characterized and show enormous variations in the coated product without longevity. Meanwhile, even if adsorbent coatings are synthesized and characterized for their pore sizes and thickness, a rational approach to scale them up is not discussed. This study focuses on the design, development, and performance demonstration of a high-performance adsorbent-coated microchannel heat exchanger for CO₂ capture. The adsorbent bed consists of Aluminum plates with cut microchannels coated with Zeolite 13X and interlayered with uncoated microchannel plates carrying a heat transfer fluid for the adsorption and desorption phase. Experiments were conducted to optimize for a highly adhesive coating to the aluminum microchannels without hindering porosity, a novel contribution from this work. The coating formula consisted of a mixture of xanthan gum as the binder agent, zeolite 13X and distilled water. Adequate adhesion was achieved whereby 97.6 – 98% of the dehydrated coating contained only Zeolite 13X while 2 – 2.4% contained the xanthan gum binder. SEM imaging of samples showed minimal effect on coating porosity, with the signature of Zeolite 13X unaffected. The system design included waterjet through cuts of various Aluminum plates with a thickness of 0.5 mm to deliver the gases and fluids, with custom laser-cut silicone gaskets to prevent leaks between each header and plate. The final assembly consisted of 7 coated plates containing a total of 21.84g Zeolite 13X, whereby each coated plate has an uncoated 1 mm thick microchannel plate directly underneath it carrying a heat transfer fluid and headers to direct gas and liquid flow accordingly. CO₂ separation experiments involving a Raman laser gas analyzer (RLGA) from a 20% CO₂ - 80% N₂ gas mixture, representing flue gas composition. Water at 50 – 65^oC is circulated through the heat transfer fluid plates for regenerating Zeolite 13X. The CO₂ mass adsorbed in Zeolite 13X is measured as a function of adsorbent mass, bed volume and energy required for desorption through temperature swing and compared with the existing CO₂ capture systems. Such characterization will underline the simplicity and scalability of coated-microchannel-based heat exchangers for decarbonization applications.

Recommended Citation

Hocheimy, Daniel Jamil, "Synthesis of Durable Zeolite 13X Insertion Coatings and Scaled-Up Experimental Demonstration for CO2 Capture" (2024). Theses and Dissertations. 1433.
https://repository.fit.edu/etd/1433