Design of LTCC-based Ceramic Structure for Chemical Microreactor

The design of ceramic chemical microreactor for the production of hydrogen needed in portable polymer-electrolyte membrane (PEM) fuel cells is presented. The microreactor was developed for the steam reforming of liquid fuels with water into hydrogen. The complex three-dimensional ceramic structure of the microreactor includes evaporator(s), mixer(s), reformer and combustor. Low-temperature co-fired ceramic (LTCC) technology was used to fabricate the ceramic structures with buried cavities and channels, and thick-film technology was used to make electrical heaters, temperature sensors and pressure sensors. The final 3D ceramic structure consists of 45 LTCC tapes. The dimensions of the structure are 75 × 41 × 9 mm3 and the weight is about 73 g

Fabrication of a Flexible Micro CO Sensor for Micro Reformer Applications

Integration of a reformer and a proton exchange membrane fuel cell (PEMFC) is problematic due to the presence in the gas from the reforming process of a slight amount of carbon monoxide. Carbon monoxide poisons the catalyst of the proton exchange membrane fuel cell subsequently degrading the fuel cell performance, and necessitating the sublimation of the reaction gas before supplying to fuel cells. Based on the use of micro-electro-mechanical systems (MEMS) technology to manufacture flexible micro CO sensors, this study elucidates the relation between a micro CO sensor and different SnO2 thin film thicknesses. Experimental results indicate that the sensitivity increases at temperatures ranging from 100–300 °C. Additionally, the best sensitivity is obtained at a specific temperature. For instance, the best sensitivity of SnO2 thin film thickness of 100 nm at 300 °C is 59.3%. Moreover, a flexible micro CO sensor is embedded into a micro reformer to determine the CO concentration in each part of a micro reformer in the future, demonstrating the inner reaction of a micro reformer in depth and immediate detection

Integrated Micro Fuel Processor And Flow Delivery Infrastructure

Apparatus for transporting a fluid, atomizers, reactors, integrated fuel processing apparatus, combinations thereof, methods of atomizing reactants, methods of moving fluids, methods of reverse-flow in a reactor, and combinations thereof, are provided. One exemplary apparatus for transporting a fluid, among others, includes: a channel for receiving a fluid; a sensor for determining an internal condition of the fluid in the channel; and a channel actuator in communication with the sensor for changing a cross-sectional area of the channel based on the internal condition, wherein the change in cross-sectional area controls a parameter selected from a pressure and a fluid flow.Georgia Tech Research Corporatio

Design and Operation of the Synthesis Gas Generator System for Reformed Propane and Glycerin Combustion

Due to an increased interest in sustainable energy, biodiesel has become much more widely used in the last several years. Glycerin, one major waste component in biodiesel production, can be converted into a hydrogen rich synthesis gas to be used in an engine generator to recover energy from the biodiesel production process. This thesis contains information detailing the production, testing, and analysis of a unique synthesis generator rig at the University of Kansas. Chapter 2 gives a complete background of all major components, as well as how they are operated. In addition to component descriptions, methods for operating the system on pure propane, reformed propane, reformed glycerin along with the methodology of data acquisition is described. This chapter will serve as a complete operating manual for future students to continue research on the project. Chapter 3 details the literature review that was completed to better understand fuel reforming of propane and glycerin. This chapter also describes the numerical model produced to estimate the species produced during reformation activities. The model was applied to propane reformation in a proof of concept and calibration test before moving to glycerin reformation and its subsequent combustion. Chapter 4 first describes the efforts to apply the numerical model to glycerin using the calibration tools from propane reformation. It then discusses catalytic material preparation and glycerin reformation tests. Gas chromatography analysis of the reformer effluent was completed to compare to theoretical values from the numerical model. Finally, combustion of reformed glycerin was completed for power generation. Tests were completed to compare emissions from syngas combustion and propane combustion

Nanoscale platinum and iron -cobalt catalysts deposited in microchannel microreactors for use in hydrogenation and dehydrogenation of cyclohexene, selective oxidation of carbon monoxide and Fischer -Tropsch process to higher alkanes

Chemical Process Miniaturization (CPM) has predominant advantages in heat and mass transfer limited unit operations, synthesis of hazardous materials, and as a process development tool. For years, engineers have been seeking ways to apply CPM to practical applications. Studies of catalysts and catalyst supports that can be applied to microreactors are important for a number of commercially desirable gas phase reactions. Parameters such as surface-to-volume ratio and the pore structure of catalyst supports influence the activity and selectivity of the catalysts. In this study, platinum, iron and cobalt catalysts were fabricated by sputtering deposition and compared with catalysts deposited by chemical procedures. The chemical methods to fabricate silica-supported or alumina-supported Pt and alumina-supported Fe/Co catalysts were investigated using the sol-gel and ion impregnation techniques. A substantial increase in the reaction surface area was observed for the sol-gel supports; however, the sol-gel could not be uniformly applied in the smaller microchannels tested. The characterization of the catalysts and supports was performed using SEM, XPS, BET surface area measurement, EDX, and VSM. The support particles are approximately 80 nm in diameter, which results in a specific surface area of 400 m2/g and dramatically increases the surface area of the catalysts in a microreactor from 0.03 m2 to 7 m2. The activity and efficiency of catalysts were evaluated in microreactors with 100 micron and 5 micron wide channels. Process optimization of the Inductive Coupled Plasma (ICP) etching was necessary to achieve the desired microchannel dimensions and uniformity. The ICP parameters\u27 studies included cycle time of SF6 gas flow, bias power, and chamber pressure. The conversion of cyclohexene to cyclohexane and benzene is the model reaction for comparison of the various deposition methods of the catalysts and the supports. In addition, screening studies were performed on two reactions of enormous commercial potential: Fischer-Tropsch (F-T) synthesis, and preferential oxidation of CO in fuel cell. An over 50% conversion of CO and 78% selectivity to propane in F-T synthesis has been achieved. Meanwhile, a 70% conversion of CO and 80% selectivity to CO2 in preferential oxidation is reached in the fuel cell feed gas reaction. Statistical modeling studies were done using a Central Composite Design (CCD) to achieve the optimal condition (temperature 158°C, CO: O2 ratio 1.77 and total flow rate 0.207 sccm) for preferential oxidation of CO in fuel cells