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ADVANCED SULFUR CONTROL CONCEPTS FOR HOT-GAS DESULFURIZATION TECHNOLOGY

Description: This research project examined the feasibility of a second generation high-temperature coal gas desulfurization process in which elemental sulfur is produced directly during the sorbent regeneration phase. Two concepts were evaluated experimentally. In the first, FeS was regenerated in a H2O-O2 mixture. Large fractions of the sulfur were liberated in elemental form when the H2O-O2 ratio was large. However, the mole percent of elemental sulfur in the product was always quite small (<<1%) and a process based on this concept was judged to be impractical because of the low temperature and high energy requirements associated with condensing the sulfur. The second concept involved desulfurization using CeO2 and regeneration of the sulfided sorbent, Ce2O2S, using SO2 to produce elemental sulfur directly. No significant side reactions were observed and the reaction was found to be quite rapid over the temperature range of 500°C to 700°C. Elemental sulfur concentrations (as S2) as large as 20 mol% were produced. Limitations associated with the cerium sorbent process are concentrated in the desulfurization phase. High temperature and highly reducing coal gas such as produced in the Shell gasification process are required if high sulfur removal efficiencies are to be achieved. For example, the equilibrium H2S concentration at 800°C from a Shell gas in contact with CeO2 is about 300 ppmv, well above the allowable IGCC specification. In this case, a two-stage desulfurization process using CeO2 for bulk H2S removal following by a zinc sorbent polishing step would be required. Under appropriate conditions, however, CeO2 can be reduced to non-stoichiometric CeOn (n<2) which has significantly greater affinity for H2S. Pre-breakthrough H2S concentrations in the range of 1 ppmv to 5 ppmv were measured in sulfidation tests using CeOn at 700°C in highly reducing gases, as measured by equilibrium O2 concentration, comparable to the Shell gas. Good sorbent ...
Date: October 31, 1998
Creator: ORTIZ, A. LOPEZ; HARRISON, D.P.; GROVES, F.R.; WHITE, J.D.; ZHANG, S.; HUANG, W.-N. et al.
Partner: UNT Libraries Government Documents Department

ADVANCED SULFUR CONTROL CONCEPTS FOR HOT GAS DESULFURIZATION TECHNOLOGY

Description: The objective of this project is to develop a hot-gas desulfurization process scheme for control of H<sub>2</sub>S in HTHP coal gas that can be more simply and economically integrated with known regenerable sorbents in DOE/METC-sponsored work than current leading hot-gas desulfurization technologies. In addition to being more economical, the process scheme to be developed must yield an elemental sulfur byproduct. The Direct Sulfur Recovery Process (DSRP), a leading process for producing an elemental sulfur byproduct in hot-gas desulfurization systems, incurs a coal gas use penalty, because coal gas is required to reduce the SO<sub>2</sub> in regeneration off-gas to elemental sulfur. Alternative regeneration schemes, which avoid coal gas use and produce elemental sulfur, will be evaluated. These include (i) regeneration of sulfided sorbent using SO<sub>2</sub> ; (ii) partial oxidation of sulfided sorbent in an O<sub>2</sub> starved environment; and (iii) regeneration of sulfided sorbent using steam to produce H<sub>2</sub>S followed by direct oxidation of H<sub>2</sub>S to elemental sulfur. Known regenerable sorbents will be modified to improve the feasibility of the above alternative regeneration approaches. Performance characteristics of the modified sorbents and processes will be obtained through lab- and bench-scale testing. Technical and economic evaluation of the most promising processes concept(s) will be carried out.
Date: September 30, 1998
Partner: UNT Libraries Government Documents Department

Bench-Scale Demonstration of Hot-Gas Desulfurization Technology

Description: The U.S. Department of Energy (DOE), Federal Energy Technology Center (FETC), is sponsoring research in advanced methods for controlling contaminants in hot coal gasifier gas (coal-derived fuel-gas) streams of integrated gasification combined-cycle (IGCC) power systems. The hot gas cleanup work seeks to eliminate the need for expensive heat recovery equipment, reduce efficiency losses due to quenching, and minimize wastewater treatment costs.
Date: December 1, 1998
Creator: Portzer, Jeffrey W. & Gangwal, Santosh K.
Partner: UNT Libraries Government Documents Department

Particulate Hot Gas Stream Cleanup Technical Issues

Description: This is the fifteenth quarterly report describing the activities performed under Contract No. DE-AC21-94MC31160. The analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. Task 1 is designed to generate a data bank of the key characteristics of ashes collected from operating advanced particle filters (APFs) and to relate these ash properties to the operation and performance of these filters and their components. APF operations have also been limited by the strength and durability of the ceramic materials that have served as barrier filters for the capture of entrained HGCU ashes. Task 2 concerns testing and failure analyses of ceramic filter elements currently used in operating APFs and the characterization and evaluation of new ceramic materials. Task 1 research activities during the past quarter included characterizations of samples collected during a site visit on May 18 to the Department of Energy / Southern Company Services Power Systems Development Facility (PSDF) and a particulate sample collected in the Westinghouse filter at Sierra Pacific Power Company�s Piñon Pine Power Project. Analysis of this Piñon Pine sample is ongoing: however, this report contains the results of analyses completed to date. Significant accomplishments were achieved on the HGCU data bank during this reporting quarter. The data bank was prepared for presentation at the Advanced Coal-Based Power and Environmental Systems �98 Conference scheduled for July, 1998. Task 2 work during the past quarter consisted of testing two Dupont PRD-66C candle filters, one McDermott ceramic composite candle filter, one Blasch 4-270 candle filter, and one Specific Surface cordierite candle filter. Tensile and thermal expansion testing is complete and the rest of the testing is in progress. Also, some 20-inch long ...
Date: August 31, 1998
Partner: UNT Libraries Government Documents Department

Fail Save Shut Off Valve for Filtering Systems Employing Candle Filters

Description: The invention relates to an apparatus that acts as a fail save shut off valve. More specifically, the invention relates to a fail save shut off valve that allows fluid flow during normal operational conditions, but prevents the flow of fluids in the event of system failure upstream that causes over-pressurization. The present invention is particularly well suited for use in conjunction with hot gas filtering systems, which utilize ceramic candle filters. Used in such a hot gas system the present invention stops the flow of hot gas and prevents any particulate laden gas from entering the clean side of the system.
Date: January 3, 2006
Creator: VanOsdol, John
Partner: UNT Libraries Government Documents Department

Granular filtration in a fluidized bed

Description: Successful development of advanced coal-fired power conversion system often requires reliable and efficient cleanup devices that can remove particulate and gaseous pollutants from high-temperature, high- pressure gas streams. A novel filtration concept for particulate cleanup has been developed at the U.S. Department of Energy`s Morgantown Energy Technology Center (METC). The filtration system consists of a fine metal screen filter immersed in a fluidized bed of granular material. As the gas stream passes through the fluidized bed, a layer of the bed granular material is entrained and deposited at the screen surface. This material provides a natural granular filter to separate fine particles from the gas stream passing through the bed. Since the filtering media is the granular material supplied by the fluidized bed, the filter is not subjected to blinding like candle filters. Because only the in-flowing gas, not fine particle cohesive forces, maintains the granular layer at the screen surface, once the thickness and permeability of the granular layer are stabilized, it remains unchanged as long as the in-flowing gas flow rate remains constant. The weight of the particles and the turbulent nature of the fluidized bed limits the thickness of the granular layer on the filter leading to a self-cleaning attribute of the filter. The granular filtration testing system consisted of a filter, a two-dimensional fluidized bed, a continuous powder feeder, a laser-based, in-line particle counting, sizing, and velocimeter (PCSV), and a continuous solid feeding/bed material withdrawal system. The two-dimensional, transparent fluidized bed allowed clear observation of the general fluidized state of the granular material and the conditions under which fines are captured by the granular layer.
Date: December 31, 1996
Creator: Mei, J.S. & Yue, P.C.
Partner: UNT Libraries Government Documents Department

Hot Gas Desulfurization PDU Project

Description: The process development unit (PDU) being constructed at METC will fill the strategic role of bridging the gap between post/current small-scale testing and future large-scale demonstrations. With the capability for both fluid-bed and transport reactor contacting, the project will provide a site for testing/proving hot gas desulfurization (HGD) process configurations and demonstrating sorbent suitability. Process conditions will be representative of anticipated commercial applications in terms of temperatures, pressures, compositions, velocities, and sorbent cycling.
Date: December 31, 1996
Creator: Bissett, L.A.
Partner: UNT Libraries Government Documents Department

Metal filter materials in combustion environments

Description: Hot gas filtration in pressurized fluidized bed combustion (PFBC) systems has been proven below 750 C (1400 F). Advanced PFBC designs, focused on operational and efficiency improvements, will require filtration at higher temperatures. E.g., in first-generation advanced PFBCs, the filters will have to perform at 870 C (1600 F), while second-generation units, with both carbonizers for fuel-gas production and fluidized-bed combustors, will eventually require filters to operate up to 930 and 870 C (1700 and 1600 F). Results from the final test campaign at the Tidd PFBC Demonstration Project showed that at these higher temperatures, ceramic filter reliability may be problematical, so it will be of interest to re-examine the possibility of using advanced metal hot-gas filters for these advanced PFBC applications in view of the exceptional corrosion resistance of Fe aluminides in high-temperature sulfur-bearing atmospheres. For the second-generation PFBCs, performance criteria for the carbonizer filters are essentially the same as those for integrated gasification combined cycle systems (reducing environments). For the combustor, issues are similar to those of advanced first-generation units (oxidizing) except that the fuel (byproduct char from carbonizer) should be somewhat clearer and filter performance requirements less demanding than for PFBC systems such as the Tidd plant. For the carbonizer system, the nearer term (market entry) goals are to develop filter materials that will perform at 650-760 C (1200-1400 F), with an increase to 800-930 C (1500-1700 F) for improved cycle efficiency.
Date: September 1, 1996
Creator: Judkins, R.R.; Tortorelli, P.F. & Wright, I.G.
Partner: UNT Libraries Government Documents Department

A new hot gas cleanup filter design methodology

Description: The fluid dynamics of Hot Gas Cleanup (HGCU) systems having complex geometrical configurations are typically analyzed using computational fluid dynamics codes (CFD) or bench-scale laboratory test facilities called cold-flow models (CFM). At the present time, both CFD and CFM can be effectively used for simple flows limited to one or two characteristic length scales with well defined boundary conditions. This is not the situation with HGCU devices. These devices have very complex geometries, low Reynolds number, multi-phase flows that operate on multiple-length scales. For this reason, both CFD and CFM analysis cannot yet be considered as a practical engineering analysis tool for modeling the entire flow field inside HGCU systems. The thrust of this work is to provide an aerodynamic analysis methodology that can be easily applied to the complex geometries characteristic of HGCU filter vessels, but would not require the tedious numerical solution to the entire set of transport equations. The analysis methodology performs the following tasks: Predicts problem areas where ash deposition will most likely occur; Predicts residence times for particles at various locations inside the filter vessel; Lends itself quickly to major design changes; Provides a sound technical basis for more appropriate use of CFD and CFM analysis; and Provides CFD and CFM analysis in a more focused way where if is needed.
Date: December 31, 1996
Creator: VanOsdol, J.G.; Dennis, R.A. & Shaffer, F.D.
Partner: UNT Libraries Government Documents Department

Advanced sulfur control concepts for hot gas desulfurization technology

Description: The objective of this project is to develop a hot-gas desulfurization process scheme for control of H{sub 2}S in HTHP coal gas that can be more simply and economically integrated with known regenerable sorbents in DOE/METC-sponsored work than current leading hot-gas desulfurization technologies. In addition to being more economical, the process scheme to be developed must yield an elemental sulfur byproduct.
Date: September 1, 1998
Partner: UNT Libraries Government Documents Department

Preliminary Strength Measurements of High Temperature Ash Filter Deposits

Description: The objective of this study is to develop and evaluate preliminary strength measurement techniques for high temperature candle filter ash deposits. The efficient performance of a high temperature gas filtering system is essential for many of the new thermal cycles being proposed for power plants of the future. These new cycles hold the promise of higher thermal efficiency and lower emissions of pollutants. Many of these cycles involve the combustion or gasification of coal to produce high temperature gases to eventually be used in gas turbines. These high temperature gases must be relatively free of particulates. Today, the candle filter appears to be the leading candidate for high temperature particulate removal. The performance of a candle filter depends on the ash deposits shattering into relatively large particles during the pulse cleaning (back flushing) of the filters. These relatively large particles fall into the ash hopper and are removed from the system. Therefore, these 1247 particles must be sufficiently large so that they will not be re-entrained by the gas flow. The shattering process is dictated by the strength characteristics of the ash deposits. Consequently, the objective of this research is to develop measurements for the desired strength characteristics of the ash deposits. Experimental procedures were developed to measure Young`s modulus of the ash deposit at room temperature and the failure tensile strain of ash deposits from room temperature to elevated temperatures. Preliminary data has been obtained for both soft and hard ash deposits. The qualifier ``preliminary`` is used to indicate that these measurements are a first for this material, and consequently, the measurement techniques are not perfected. In addition, the ash deposits tested are not necessarily uniform and further tests are needed in order to obtain meaningful average data.
Date: December 31, 1996
Creator: Kang, B.S.; Johnson, E.K.; Mallela, R. & Barberio, J.F.
Partner: UNT Libraries Government Documents Department

PRD-66 Gas Filter Development

Description: The PRD-66 manufacturing process offers a unique approach to the production of hot gas candle filters for application in Pressurized Fluidized Bed Combustors (PFBC) and Integrated Gas Combined Cycle (IGCC) power systems. Fabricated from readily available and inexpensive raw materials, the PRD-66 process uses an admixture of textile and ceramic concepts to produce an all-oxide filter element containing no refractor ceramic fiber (RCF) residues in the finished products. The use demonstration of textile grade glass yarn as a consumable reactant gives the advantages of fabrication versatility and shape control and a unique micro-layered phase structure in the fired product, resulting in unsurpassed thermal shock resistance and operating temperature capability of greater than 1200{degrees}C in a low-cost package. This high throughput, adaptable process allows tailoring of filter element dimensions and operating properties to specific system needs with short lead times and low cost penalties.
Date: July 1, 1997
Creator: Forsythe, G.D. & Connolly, E.S.
Partner: UNT Libraries Government Documents Department

Advanced hot-gas filter development

Description: Coal is the most abundant fossil-fuel resource in the United States. `Clean coal` technologies, such as pressurized fluidized-bed combustion (PFBC) and integrated gasification combined-cycle (IGCC), require a hot gas filter to remove the corrosive and erosive coal ash entrained in the combustion gas stream. These hot gas filters, or candle filters, must be cost-effective while able to withstand the effects of corrosion, elevated temperature, thermal shock, and temperature transients. Ash loadings may range from 500 to 10,000 ppm by weight, and may contain particles as fine as 0.008 mils. The operating environment for the hot gas filter can range in pressure from 10 to 20 atm, in temperatures from 700 to 1750{degrees}F, and can be oxidizing or reducing. In addition, the process gases may contain volatile chloride, sulfur, and alkali species. Field testing of various commercially available, porous, ceramic filter matrices has demonstrated a loss of up to 50 percent of as-manufactured strength after 1,000 to 2,000 hours of exposure to these operating conditions, although full-scale elements have remained intact during normal process operations. Ultramet, a small business specializing in advanced materials R&D, has developed a new class of hot gas filter materials that offers lower back-pressure, higher permeability, longer life, and high filtration efficiency in the PFBC and IGCC environments. Subscale Ultrafoam Duplex Filter elements have undergone accelerated corrosion testing at temperatures of up to 2370{degrees}F (at Ultramet), and have been subjected to over 2,800 hours of exposure to hot PFBC gases (in the Westinghouse Advanced Particulate Filtration System at Brilliant, OH) without any loss in strength in either case. The Ultrafoam Duplex Filter matrix demonstrated 100 percent particle- capture efficiency of coal ash, and had an initial pressure drop of 0.1 to 0.6 in-wc/fpm. The Ultrafoam Duplex Filter is composed of a chemical vapor deposition (CVD), silicon carbide ...
Date: December 31, 1997
Creator: Stankiewicz, E.P.; Sherman, A.J. & Zinn, A.A.
Partner: UNT Libraries Government Documents Department

Advanced sulfur control concepts for hot gas desulfurization technology

Description: The objective of this project is to develop a hot-gas desulfurization process scheme for control of H{sub 2}S in HTHP coal gas that can be more simply and economically integrated with known regenerable sorbents in DOE/METC-sponsored work than current leading hot-gas desulfurization technologies. In addition to being more economical, the process scheme to be developed must yield an elemental sulfur byproduct.
Date: September 1, 1998
Partner: UNT Libraries Government Documents Department

Task 3.13 -- Hot-gas filter testing. Semi-annual report, January 1--June 30, 1995

Description: The objectives of the hot-gas cleanup (HGC) work on the transport reactor demonstration unit (TRDU) located at the Energy and Environmental Research Center (EERC) is to demonstrate acceptable performance of hot-gas filter elements in a pilot-scale system prior to long-term demonstration tests. The primary focus of the experimental effort in the 2-year project is the testing of hot-gas filter element performance (particulate collection efficiency, filter pressure differential, filter cleanability, and durability) as a function of temperature and filter face velocity during short-term operation (100--200 hours). This filter vessel is used in combination with the TRDU to evaluate the performance of selected hot-gas filter elements under gasification operating conditions. This work directly supports the power systems development facility (PSDF) utilizing the M.W. Kellogg transport reactor located at Wilsonville, Alabama and, indirectly, the Foster Wheeler advanced pressurized fluid-bed combustor, also located at Wilsonville.
Date: August 1, 1997
Creator: Mann, M.D.
Partner: UNT Libraries Government Documents Department

Scale-Up of Advanced Hot-Gas Desulfurization Sorbents

Description: The overall objective of this project is to develop regenerable sorbents for hot gas desulfurization in IGCC systems. The specific objective of the project is to develop durable advanced sorbents that demonstrate a strong resistance to attrition and chemical deactivation, and high activity at temperatures as low as 343{degrees}C (650{degrees}F). A number of formulations will be prepared and screened in a 1/2-inch fixed bed reactor at high pressure (1 to 20 atm) and high temperatures using simulated coal-derived fuel-gases. Screening criteria will include, chemical reactivity, stability, and regenerability over the temperature range of 343{degrees}C to 650{degrees}C. After initial screening, at least 3 promising formulations will be tested for 25-30 cycles of absorption and regeneration. One of the superior formulations with the best cyclic performance will be selected for investigating scale up parameters. The scaled-up formulation will be tested for long term durability and chemical reactivity.
Date: April 21, 1997
Creator: Jothimurugesan, K. & Gangwal, S.K.
Partner: UNT Libraries Government Documents Department

Carbon Formation and Metal Dusting in Hot-Gas Cleanup Systems of Coal Gasifiers

Description: There are several possible materials/systems degradation modes that result from gasification environments with appreciable carbon activities. These processes, which are not necessarily mutually exclusive, include carbon deposition, carburization, metal dusting, and CO disintegration of refractories. Carbon formation on solid surfaces occurs by deposition from gases in which the carbon activity (a sub C) exceeds unity. The presence of a carbon layer CO can directly affect gasifier performance by restricting gas flow, particularly in the hot gas filter, creating debris (that may be deposited elsewhere in the system or that may cause erosive damage of downstream components), and/or changing the catalytic activity of surfaces.
Date: December 31, 1995
Creator: Tortorelli, Peter F.; Judkins, Roddie R.; DeVan, Jackson H. & Wright, Ian G.
Partner: UNT Libraries Government Documents Department

Hot-Gas Filter Ash Characterization Project

Description: Large-scale hot-gas filter testing over the past 10 years has revealed numerous cases of cake buildup on filter elements that has been difficult, if not impossible, to remove. At times, the cake can blind or bridge between candle filters, leading to filter failure. Physical factors, including particle-size distribution, particle shape, the aerodynamics of deposition, and system temperature, contribute to the difficulty in removing the cake, but chemical factors such as surface composition and gas-solid reactions also play roles in helping to bond the ash to the filters or to itself. This project is designed to perform the research necessary to determine the fuel-, sorbent-, and operations-related conditions that lead to blinding or bridging of hot-gas particle filters. The objectives of the project are threefold: (1) Determine the mechanisms by which a difficult-to-clean ash is formed and how it bridges hot-gas filters (2) Develop a method to determine the rate of bridging based on analyses of the feed coal and sorbent, filter properties, and system operating conditions and (3) Suggest and test ways to prevent filter bridging.
Date: July 1, 1997
Creator: Swanson, M.L.; Hurley, J.P.; Dockter, B.A. & O`Keefe, C.A.
Partner: UNT Libraries Government Documents Department

Particulate Hot Gas Stream Cleanup Technical Issues

Description: The characteristics of entrained particles generated by advanced coal conversion technologies and the harsh flue gas environments from which these particles must be removed challenge current ceramic barrier filtration systems. Measurements have shown that the size distribution, morphology, and chemical composition of particles generated by pressurized fluidized-bed combustion (PFBC) and gasification processes differ significantly from the corresponding characteristics of conventional pulverized-coal ash particles. The entrained particulate matter from these advanced conversion technologies often comprise fine size distributions, irregular particle morphologies, high specific surface areas, and significant proportions of added sorbent material. These characteristics can create high ash cohesivity and high pressure losses through the filter cakes. In addition, the distributions of chemical constituents among the collected particles provide local, highly concentrated chemical species that promote reactions between adjacent particles that ultimately cause strong, nodular deposits to form in the filter vessel. These deposits can lead directly to bridging and filter element failure. This project is designed to address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic filter elements. The activities conducted under Task 1, Assessment of Ash Characteristics, are discussed in this paper. Activities conducted under Task 2, Testing and Failure Analysis of Ceramic Filters, are discussed in a separate paper included in the proceedings of the Advanced Coal-Based Power and Environmental Systems `97 Conference. The specific objectives of Task I include the generation of a data base of the key characteristics of Hot Gas Stream Cleanup (HGCU) ashes collected from operating advanced particle filters (APFS) and the identification of relationships between HGCU ash properties and the operation and performance of APFS. During the past year, particulate samples have been characterized from the DOE/FETC Modular Gas Cleanup Rig (MGCR), the Transport Reactor Demonstration Unit (TRDU) located at ...
Date: July 1, 1997
Creator: Potius, D. & Snyder, T.
Partner: UNT Libraries Government Documents Department

Particulate hot gas stream cleanup technical issues

Description: This is the tenth in a series of quarterly reports describing the activities performed under Contract No. DE-AC21-94MC31160. Analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic bed filter elements. Task I is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFS) and to relate these ash properties to the operation and performance of these filters. Task 2 concerns testing and failure analysis of ceramic filter elements. Under Task I during the past quarter, analyses were performed on a particulate sample from the Transport Reactor Demonstration Unit (TRDU) located at the University of North Dakota Energy and Environmental Research Center. Analyses are in progress on ash samples from the Advanced Particulate Filter (APF) at the Pressurized Fluidized-Bed Combustor (PFBC) that was in operation at Tidd and ash samples from the Pressurized Circulating Fluid Bed (PCFB) system located at Karhula, Finland. A site visit was made to the Power Systems Development Facility (PSDF) to collect ash samples from the filter vessel and to document the condition of the filter vessel with still photographs and videotape. Particulate samples obtained during this visit are currently being analyzed for entry into the Hot Gas Cleanup (HGCU) data base. Preparations are being made for a review meeting on ash bridging to be held at Department of Energy Federal Energy Technology Center - Morgantown (DOE/FETC-MGN) in the near future. Most work on Task 2 was on hold pending receipt of additional funds; however, creep testing of Schumacher FT20 continued. The creep tests on Schumacher FT20 specimens just recently ended and data analysis and comparisons to other data are ongoing. A ...
Date: September 1, 1998
Partner: UNT Libraries Government Documents Department

ADVANCED HOT GAS FILTER DEVELOPMENT

Description: This report describes the fabrication and testing of continuous fiber ceramic composite (CFCC) based hot gas filters. The fabrication approach utilized a modified filament winding method that combined both continuous and chopped fibers into a novel microstructure. The work was divided into five primary tasks. In the first task, a preliminary set of compositions was fabricated in the form of open end tubes and characterized. The results of this task were used to identify the most promising compositions for sub-scale filter element fabrication and testing. In addition to laboratory measurements of permeability and strength, exposure testing in a coal combustion environment was performed to asses the thermo-chemical stability of the CFCC materials. Four candidate compositions were fabricated into sub-scale filter elements with integral flange and a closed end. Following the 250 hour exposure test in a circulating fluid bed combustor, the retained strength ranged from 70 t 145 percent of the as-fabricated strength. The post-test samples exhibited non-catastrophic failure behavior in contrast to the brittle failure exhibited by monolithic materials. Filter fabrication development continued in a filter improvement and cost reduction task that resulted in an improved fiber architecture, the production of a net shape flange, and an improved low cost bond. These modifications were incorporated into the process and used to fabricate 50 full-sized filter elements for testing in demonstration facilities in Karhula, Finland and at the Power Systems Development Facility (PSDF) in Wilsonville, AL. After 581 hours of testing in the Karhula facility, the elements retained approximately 87 percent of their as-fabricated strength. In addition, mechanical response testing at Virginia Tech provided a further demonstration of the high level of strain tolerance of the vacuum wound filter elements. Additional testing in the M. W. Kellogg unit at the PSDF has accumulated over 1800 hours of coal firing at ...
Date: September 4, 1998
Creator: WAGNER, RICHARD A.
Partner: UNT Libraries Government Documents Department

Engineering a new material for hot gas cleanup

Description: The engineering development of a promising sorbent for desulfurizing hot coal gas was initiated and preliminary results are presented. The sorbent is calcium-based and is designed to be regenerated and reused repeatedly. It is prepared by pelletizing powdered limestone in a rotating drum pelletizer followed by the application of a coating which becomes a strong, porous shell upon further treatment. The resulting spherical pellets combine the high reactivity of lime with the strength of an inert protective shell. Preliminary work indicates that a satisfactory shell material is comprised of a mixture of ultrafine alumina powder, somewhat coarser alumina particles, and pulverized limestone which upon heating to 1,373 K (1,100 C) becomes a coherent solid through the mechanism of particle sintering. Several batches of core-in-shell pellets were prepared and tested with encouraging results.
Date: March 1, 2000
Creator: Wheelock, T.D.; Doraiswamy, L.K. & Constant, K.
Partner: UNT Libraries Government Documents Department

PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES

Description: This quarterly report describes technical activities performed under Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under Task 1 of this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This report reviews the status of the HGCU data bank of ash and char characteristics, including the interactive querying of measured particulate properties. Task 1 plans for the remainder of the project include completion and delivery of the HGCU data bank, and issuance of a comprehensive final report on activities conducted under Task 1. Task 2 of this project concerns the testing and failure analyses of new and used filter elements and filter materials. Task 2 work during the past quarter included preliminary testing of two materials. One material tested was the soft candle filter manufactured by CGC and supplied by ABB. The other material was N610/mullite manufactured by Albany International (AIT).
Date: August 30, 1999
Creator: Pontius, D.H.
Partner: UNT Libraries Government Documents Department