Toward Direct Thermal-to-Electric Conversion: On-chip Microreactors for Catalytic Combustion of Methanol-Air Mixture

• Author / Creator

  Tian, Sheng

• In this thesis, on-chip microreactors for catalytic combustion of methanol-air mixture were designed, fabricated and characterized. Using standard optical lithography, deep reactive-ion etching (DRIE) and other fabrication techniques, microreactors with integrated micropillars having four different types of designs, viz., square and staggered pillar arrangements along with axial and diagonal flow configurations were generated. The diameter and height of the micropillars are both 100 um and the available internal surface area of the reactor is 629.77 mm^2. Such microfabricated microreactors have a high surface-area-to-volume-ratio in the order of 27.80 mm^-1. A wash-coating procedure was adopted to deposit Pt on Al2O3 catalyst onto the reactor surfaces. After a preheating procedure, by introducing methanol-air mixture into the reactors, an autonomous and stable on-chip catalytic combustion could be sustained. This work shows that apart from the catalyst, fuel type, fuel and air flow rates, the geometric configuration of the microreactor plays a significant role in terms of achieving highest on-chip temperature. It was found that the on-chip microreactor with squared pillar arrangement coupled with diagonal flow configuration provided the best performance for the catalytic combustion of methanol-air mixture. It was also demonstrated that the well-known transition from heterogeneous catalytic combustion to a mixed heterogeneous-catalytic-and-homogeneous-gas-phase combustion exists during the combustion process in these on-chip microreactors. Such sustained catalytic combustion can be utilized as future heat source for direct thermal-to-electric energy conversion platform where the on-chip microreactors can be packaged with commercial thermoelectric modules to achieve power generation on-chip.

• Subjects / Keywords

  • Direct Thermal-to-Electric Conversion
  • Microreactor
  • Catalytic Combustion
  • Microfabrication

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3HD7P04H

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.