—by Stephanie Gooch & Richard Mandel

Last month a new manufacturing facility opened in Frankfurt, Germany that will build high temperature membrane electrode assemblies (MEAs) for fuel cells. Celanese AG has developed a polymer electrolyte membrane (PEM) fuel cell that can be used in microapplications, such as mobile telephones and small appliances, as well as larger applications such as small power plants and cars and buses. At the heart of the PEM fuel cell is the MEA, where hydrogen and oxygen react to generate electricity and heat. Conventional PEM fuel cells operate in temperatures around 100°C, whereas the high temperature MEA, working at temperatures up to 200°C, is more resistant to carbon monoxide impurities in the hydrogen, while water and heat management is simplified and more cost-effective. The MEA consists of catalysts, gas diffusion layers, and the Celtec membrane, made with the company’s temperature-resistant polymer polybenzimidazole. This membrane is permeable to protons and has electrodes on both sides. Protons are generated on the hydrogen electrode in an electrochemical reaction and are then transported through the membrane. Reduced oxygen from the oxygen electrode then combines with the hydrogen protons to form water. To balance the charge, an electric current flows in the outer electric circuit between the electrodes, which can then be used to power electrical consumer loads. Celanese AG or connect directly at www.rsleads.com/210df-100

Kerosene — the same as fuels an oil lantern — is being considered as a fuel for two main engine candidates for a second-generation reusable launch vehicle, now in development by the Space Launch Initiative. The Initiative is NASA’s technology development program for designing a complete space transportation system with increased safety and reliability at a lower cost. Managed by the Marshall Space Flight Center in Huntsville, AL, the Space Launch Initiative Propulsion Project Office is developing both the kerosene-fueled RS-84 prototype engine with Boeing Rocketdyne, Canoga Park, CA, and the TR107 prototype engine with TRW Space and Electronics of Redondo Beach, CA. Kerosene is a low maintenance fuel, that allows easier ground handling and decreased operational costs, as compared to hydrogen. In addition, because it is not a cryogenic fuel like hydrogen, the propulsion system does not require insulation for propulsion-related ducts, valves, lines and actuators — saving weight and cost. Kerosene was used as a propellant in the F-1 engines on the Saturn V rockets that propelled Apollo astronauts to the Moon. What is new is a staged combustion cycle that results in greater fuel efficiency than the F-1’s gas generator cycle by reusing some of the fuel and oxidizer used in the pre-burner to power the main combustion chamber. Pre-burners heat the propellants to ready them for the engine’s turbo pumps before the propellants are injected into the main combustion chamber, where the fuels combust to create thrust. To achieve a higher performance level, the propellant is burned at higher pressure permitting a reduction in the size of the main combustion chamber. The smaller engine will generate a powerful 1.1 million pounds of force — only 400,000 pounds of force lower than the F-1 engine. However, kerosene is not as efficient a coolant as hydrogen — a fuel more commonly used as a first- or second-stage propellant in the U.S. space program. To help offset these challenges, engineers are looking for ways to limit the kerosene temperature while cooling the thrust chamber and limiting the sooty kerosene build-up in the turbine drive systems. NASA, or connect directly at www.rsleads.com/210df-101