Pingying Zeng

A ceramic-membrane-based methane combustion reactor with tailored function of simultaneous separation of carbon dioxide from Nitrogen

Today, industry has become more dependent on natural gases and combustion processes, creating a tremendous pressure to reduce their emissions. Although the current methods such as chemical looping combustion (CLC) and pure oxygen combustion have several advantages, there are still many limitations. A ceramic membrane based methane combustion reactor is an environmentally friendly technique for heat and power generation. This work investigates the performance of a perovskite-type SrSc0.1Co0.9O3-δ (SSC) membrane reactor for the catalytic combustion of methane. For this purpose, the mixed ionic and electronic conducting SSC oxygen-permeable planar membrane was prepared by a dry-pressing technique, and the SSC powder catalyst was spray coated on the permeation side of the membrane. Then, the prepared SSC membrane with the catalyst was used to perform the catalytic combustion of methane. The oxygen permeability of the membrane reactor was studied. Also, the methane conversion rates and CO2 selectivity at various test conditions were reported.Copyright

Thermal Transpiration Based Propulsion

Thermal transpiration based propulsion is studied. Thermal transpiration describes flowing of the gas through a narrow channel with an imposed temperature gradient. As gas flows from the cold to hot side in the chamber, a pressure gradient is created across the channel induced by the temperature gradient. Between the two sides of the chamber an aerogel substance, which functions as an excellent insulator, is used as a thermal transpiration membrane and allows gas diffuse to the hot chamber. The induced pressure gradient is the driving factor in the propulsion of air, or any gas, into the chamber and through the porous membrane. The use of a porous substance such as aerogel as the transpiration membrane and a pressure gradient served as the two requirements in order to successfully achieve thermal transpiration. The gas diffusion through the aerogel transpiration membrane indicates that the average pore size of the aerogel must be comparable with the free path of the molecules. This concept can be taken further if the outlet chamber served as a combustion reactor. The flowing gas is motivated by the heat produced from the combustion process. Along with the exceptionally low thermal conductivity of the aerogel, the gas flow permits the propulsion device to be self-sustaining. The implications of providing a self-sustaining heat source signify that no external electrical heating is required. The effectiveness of this device can be measured as a function of the porous size of the membrane and the temperature difference applied to the system and pressure gradient created.© 2014 ASME

Single-phase ceramic membranes integrated with combustion processes

La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF6428) hollow fibre oxygen-permeable membranes were fabricated by extrusion technique. The oxygen permeability of a blank hollow fibre membrane was investigated with helium as sweeping gas. The oxygen permeation flux result was reported, agreeing very well with previous work. Then the hollow fibre membrane was packed with LSCF6428 catalyst and assembled as hollow fibre membrane reactor for methane combustion, aiming to separate the CO2 in the combustion exhaust from the nitrogen in air. The CO2 selectivity at various conditions was studied.Copyright

An Electricity and Value-Added Gases Co-Generation via Solid Oxide Fuel Cells

In this study, an electricity and value-added chemicals cogeneration system using methane-fueled single chamber solid oxide fuel cells (SC-SOFCs) was successfully developed and investigated. The SC-SOFCs, which operated on methane/oxygen gas mixture with a ratio of 2:1, achieved an open-circuit voltage of 1.0 V and a maximum peak power density of ∼ 840 mW.cm-2 at 700 °C. By passing the exhaust gas of the fuel cell through a Ru/Al2O3 catalyst at 700 °C, the synthesis gas is obtained with a methane conversion of higher than 95%, while CO and H2 selectivity is higher than 92%. This study provides a novel strategy for energy conversion which is one of the major concerns in energy field and a new frontier for improving the energy efficiency of SOFCs.Copyright

Combustion-Driven Thermal Transpiration Based Minature SOFC Power Generation Device

A miniature pump was designed in this study, based on a catalytic combustion-driven thermal transpiration. The designed pump was further used to build a miniature power generator that has self-pumping and power generation integrated into one device, has no moving parts and operates only on thermal and electrochemical energy supplied by hydrocarbon fuels. A solid oxide fuel cell tested with this power generator obtained a power density of 40 mW.cm−2 .Copyright

Catalytic Combustion-Driven Thermal Transpiration Pump and Power Generation Device

A miniature pump based on catalytic combustion-driven thermal transpiration was designed in this study. This designed pump was further used to build a miniature power generator that has self-pumping and power generation integrated into one device, has no moving parts and operates only on thermal and electrochemical energy supplied by hydrocarbon fuels. A solid oxide fuel cell tested with this power generator obtained a power density of 20 mW/cm 2 .