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Economical CO2, SOx, and NOx capture from fossil-fuel utilization with combined renewable hydrogen production and large-scale carbon sequestration Danny Daya, Corresponding Author Contact Information, E-mail The Corresponding Author, Robert J. Evansb, James W. Leec and Don Reicoskyd aEprida, Inc., 6300 Powers Ferry Road, Suite 307, Atlanta, GA 30339, USA bNational Renewable Energy Laboratory, 1617 Cole Blvd, Golden, CO 80401, USA cOak Ridge National Laboratory, 4500N, A16, MS-6194, Oak Ridge, TN 37831, USA dUSDA-Agricultural Research Service, 803 Iowa Avenue, Morris, MN 56267, USA Available online 17 November 2004. Purchase the full-text article References and further reading may be available for this article. To view references and further reading you must purchase this article. Abstract The objective of this project was to investigate and demonstrate production methods at a continuous, bench-scale level and generate sufficient material for an initial evaluation of a potentially profitable method of producing bioenergy and sequestering carbon. The novel process uses agricultural, forestry, and waste biomass to produce hydrogen using pyrolysis and reforming technologies conducted in a 50 kg/h pilot demonstration. The test runs produced a novel, nitrogen-enriched, slow-release, carbon-sequestering fertilizer. Seven kilograms of the material were produced for further plant growth response testing. A pyrolysis temperature profile was discovered that results in a carbon char with an affinity for capturing CO2 through gas phase reaction with mixed nitrogen-carrying nutrient compounds within the pore structures of the carbon char. A bench-scale project demonstrated a continuous process fluidized-bed agglomerating process. The total amount of CO2 sequestration was managed by controlling particle discharge rates based on density. The patent-pending process is particularly applicable to fossil-fuel power plants as it also removes SOx and NOx, does not require ene

hydrogen

CO-shift The processes described above produce gas with a high content of carbon monoxide - CO. It is therefore necessary to put the gas through the CO-shift process to increase the content of hydrogen. The shift reaction (see sidebar) is a two-step process to achieve the most complete reaction between CO and steam. Initially steam is added in a high-temperature step (300-500ºC), followed by a a low-temperature step (200ºC), with different catalysts in the two steps. Separation of CO2 Each of the processes described above produces CO2 in addition to H2. To separate hydrogen and CO2, it is common to use amine based absorption processes. This is conventional technology. Methods based on selective membranes or sorbents are under development.

arbon Dioxide Removal Print Page Fossil fuels are the primary sources of carbon dioxide emissions to the atmosphere. Much of the anticipated worldwide effort to reduce carbon dioxide emissions will focus on large point sources such as power plants and petroleum refineries. To contribute to this effort, RTI is actively engaged in a research and development project to develop a new process for removing carbon dioxide from industrial gas streams. RTI's process uses a solid, regenerable, sodium-based adsorbent to remove carbon dioxide from flue gases that fuel power plants. The regeneration of this sorbent produces a gas stream containing only carbon dioxide and water. Condensation separates the water out, leaving a pure carbon dioxide stream that can be used or sequestered. One of the relevant reactions based upon the use of sodium bicarbonate as the sorbent precursor is as follows: 2NaHCO3(s) Na2CO3(s) + CO2(g) + H2O(g) RTI has developed a 2-reactor system for removing the carbon dioxide. Both the adsorption of carbon dioxide and regeneration of the sorbent take place at low temperature (under 150°C). Laboratory experiments at RTI have demonstrated multiple cycles of the adsorption and regeneration phases. In addition, we have developed process information on * Effect of operating conditions * Effect of other feed stream components * Reaction kinetics * Heat and material balances from proc

Producing fuel alcohol via hydrolysis of lignocellulosic biomass leaves a considerable amount of residues waiting for treatment. A study was carried out on the preparation of hydrogen via catalytic gasification of residues from biomass hydrolysis with a novel Ni/modified dolomite binary catalyst, which was prepared by a two-step coprecipitation method and proved available for hydrogen production in terms of both activity and strength. The effects of four operation parameters, that is, the fluidized bed temperature, the catalytic fixed bed temperature, the particle size of the catalyst, and S/B (i.e., the mass ratio of steam to biomass material fed into the fluidized bed per unit time), on hydrogen yield were investigated. The results indicate that hydrogen yield increases with an increase in the temperature of either the fluidized bed or the downstream catalytic fixed bed or the S/B ratio or a reduction in the particle size of the catalyst. The optimum range for each of the four operation parameters from a comprehensive consideration is as follows: 800-850 °C for both the fluidized bed temperature and the catalytic fixed bed temperature, 1.5-2 for the S/B ratio, and 2.0-3.0 mm for the particle size of the catalyst. Furthermore, the gas product from catalytic gasification of residues from biomass hydrolysis contains less CO and CO2 and has a higher H2/CO ratio compared with that of the sawdust. The hydrogen yield of the former is also much higher than that of the latter. These suggest that residues from biomass hydrolysis are an even better gasification material than the original sawdust. This paper provides a novel effective method for modifying the calcined dolomite, which endows the catalyst with satisfactory strength while retaining high activity, and opens a new promising way for utilizing the residues from biomass hydrolysis. Download the full text: PDF | HTML

An improved process is provided for the removal of sulfur oxides from gas or vapor media containing oxygen and water by contacting said media with a catalytically-active carbonaceous char. The improvement is provided by the use of a catalytically-active carbonaceous char prepared by low-temperature carbonization and oxidation of a bituminous coal or bituminous coal-like material followed by exposure to a nitrogen-containing compound during the initial high-temperature exposure of the low-temperature oxidized char. Following this initial high-temperature treatment the material can be further calcined or activated as desired.