Materials for the Hydrogen Economy Edited by Russell H doc

[...]... becoming molten and flowing down the refractory sidewalls of the gasifier The liquefied slag is then removed at the base of the gasifier The carbon feedstock injected into the hot gas in the second stage becomes char that is later recycled as feed into the lower injector In the second stage, where the balance of the carbon feedstock is introduced into the gasifier, an endothermic gasification reaction... current research efforts are focused on materials and chemical approaches, where the chemical bonding between hydrogen and other elements increases the volumetric density beyond the liquid state With the recent launch by the U.S DOE (Department of Energy) of a national “Grand Challenge” for hydrogen storage development, a number of exciting new research directions have appeared that have shown good progress... Issues in Hydrogen Production Using Gasification 11 the base of the quench chamber One of two techniques is used to cool the syngas: a syngas cooler with heat exchangers or a water quench system A scrubber then cleans and cools the syngas for processing or use elsewhere Depending on the amount of scrubber fines and the carbon content of them, the fine particulate may be recycled to the gasifier The raw... than a hundred years, the geologic time span equivalent of the blink of an eye in human time, we have burned a significant fraction of the earth’s oil reserves and have also burned large quantities of other hydrocarbons, such as coal and natural gas The carbon released into the atmosphere during this interval, in the form of CO2, had been locked up for millions of years within the earth’s crust The. .. focused on materials with high hydrogen capacity The FreedomCAR and Fuel Partnership (an industry–government partnership) has established very challenging system-level performance targets for storage, for example, gravimetric energy density targets of 6 wt% H2 for 2010 and 9 wt% H2 for 2015.7 Since these targets include the mass of system components, the storage materials must have even higher hydrogen. .. ammonia, a hydrocarbon, or other form or local production of H2 could alter some of the issues but is not likely to totally eliminate them The safety of hydrogen distribution is a primary issue that affects material choice The closer to population centers, the higher the risk and the more conservative the design Hydrogen storage and transport in steel pipelines have been done successfully in the industrial... emissions or the U.S dependence on foreign fossil fuels There are a number of processes that can produce H2 by the dissociation of water or steam These include low- and high-temperature electrolysis, solar and photoelectrochemical processes, and thermochemical processes such as the sulfur–iodine process The source of the energy to dissociate water is a key to whether these processes will reduce greenhouse... but the hightemperature, high-pressure units currently used by the chemical, petrochemical, and  5024.indb 1 11/18/07 5:44:19 PM  Materials for the Hydrogen Economy power industries were first developed and put into commercial service in the 1950s and 1960s, and are greatly improved technologically over those of the past.1 They are widely used in industries such as the petrochemical to process heavy... with over 24 × 109 metric tons of CO2 (2002 values) released to the atmosphere every year,1 potentially altering the energy balance in the earth’s atmosphere Furthermore, there is a complex, dynamic interplay among carbon levels in the atmosphere, the oceans, the ground, and the earth’s flora and fauna These interactions are not completely understood Should we wait to observe ever larger changes in the. .. Advantages of autothermal reforming are that it operates at lower temperatures than the partial oxidation reaction and results in higher H2 concentration.14 In the above reactions, the partial oxidation process is the basis for producing H2 and CO by gasification As mentioned, depending on the amount of H2 desired, other processes such as the water shift gas reaction may be used at the gasification facility . on materials and chemi - cal approaches, where the chemical bonding between hydrogen and other elements increases the volumetric density beyond the liquid state. With the recent launch by the. thank my wife, Cathy, for her support during the time needed to assemble this book, the contributors who helped make it a reality, and the publisher for their patience with this project. — Russell. balance in the earth’s atmosphere. Furthermore, there is a complex, dynamic interplay among carbon levels in the atmosphere, the oceans, the ground, and the earth’s ora and fauna. These interactions