Metal Filter Materials in Combustion Environments
Metal Filter Materials in Combustion Environments

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Published: 1996

Total Pages: 5

ISBN-13:

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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.

Evaluation of Ceramic Filter Material, Selection for Application
Evaluation of Ceramic Filter Material, Selection for Application

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Published: 1993

Total Pages: 26

ISBN-13:

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Field testing in several of the Westinghouse Advanced Particulate Filtration (APF) systems has indicated that the oxide-based materials are more susceptible to thermal shock which results from system transients (i.e., combustion of char or reducing gases; system startup/turbine transients). The current clay bonded silicon carbide filter materials have a higher thermal shock resistance, but appear to be more susceptible to high temperature creep, as well as to changes that occur within the binder phase(s). Strength has frequently been used to assess what effects advanced coal fired process systems have on the stability and projected life of the various porous ceramic filter materials (Tables 1 and 2). Based on the numerous phase changes that occur, and the influence of pulse cleaning on the thermal fatigue characteristics of both the alumina/mullite and clay bonded silicon carbide filter materials, alternate material properties as thermal conductivity, thermal coefficient of expansion, elastic modulus, fracture toughness, and emissivity as a function of thermal/chemical aging are now being considered as critical factors for projecting filter durability and operating life. Table 3 provides a summary of the as-manufactured material properties for the alumina/mullite and clay bonded silicon carbide filter materials which have been used in the Westinghouses̀ APF systems. Effort is currently being directed to determine how these properties change during thermal aging of the filters in various subpilot and pilot plant systems.

Filters and Filtration Handbook
Filters and Filtration Handbook

Author: T. Christopher Dickenson

Publisher:

Published: 1992

Total Pages: 848

ISBN-13:

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This is a reference manual for the selection and application of filtration and separation products. The new edition is extended and updated to incorporate all the latest developments in filtration and separation technology supplied by both manufacturers and users. operators, consultants, as well as staff with responsibility for purchasing, planning, sales and marketing. It is directly relevant to numerous industries including water, fluid power, chemicals, pharmaceutical, food and beverages, processing, general engineering, electronics and manufacturing.

Ultra-filtration System Uses Ceramic Filters
Ultra-filtration System Uses Ceramic Filters

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Published: 1994

Total Pages: 4

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An ultra-filtration system has been installed at Ferro Techniek BV in the Netherlands. This system is equipped with ceramic membranes to separate heavy metals from waste water released by an enamelling process. In comparison to the previous system, in which polymer membranes were used, 72,000 kWh of electricity, worth NLG 9,900, is saved annually. A further saving of NLG 8,400 is made on reduced maintenance costs. This leads to a payback period on the NLG 125,000 investment of less than seven years.

Properties of Ceramic Filters
Properties of Ceramic Filters

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Published: 1996

Total Pages: 18

ISBN-13:

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The mechanical integrity of ceramic filter elements is a key issue for hot gas cleanup systems. To meet the demands of advanced power systems, the filter components sustain thermal stresses of normal operations (pulse cleaning), of start-up and shut-down, and of process upsets such as excessive ash accumulation without catastrophic failure. They must also survive various mechanical loads associated with handling and assembly, normal operation, and process upsets. For near-term filter systems, the elements must also survive operating temperature of 1650°F for three years. Objectives of the testing conducted were as follows: (1) measure basic physical, mechanical and thermal properties of candle filter materials and relate these properties to in-service performance, (2) perform post-exposure testing of candle-filter materials after service at Tidd and Karhula and compare post-exposure results to as-manufactured results to evaluate property degradation, (3) based on measured properties and in-service performance, develop an understanding of material requirements for candle-filter materials and help establish property goals, and (4) establish a test protocol for evaluation of candle filter materials.

Development of a Ceramic Foam Filter for Filtering Molten Aluminum Alloy in Casting Processes
Development of a Ceramic Foam Filter for Filtering Molten Aluminum Alloy in Casting Processes

Author: Ehsaanreza Bagherian

Publisher:

Published: 2009

Total Pages: 212

ISBN-13:

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Metal casting component are found in 90 percent of manufactured goods and equipment, from critical components for aircraft and automotive industry to home applications. However, molten metal used to produce metal casting in practice generally contains impurities and inclusions which are deleterious to final cast metal product. Currently, filtration technique by using ceramic foam filter has been accepted as a successful method of reducing inclusions from molten metal during the casting of metal parts. The present research has been done to fabricate and improve a ceramic foam filter for using in filtration of molten metal, especially aluminium based alloys. It is an objective of the present innovation to provide a ceramic foam filter characterized by cost of raw materials. Ceramic foam filters are produced by impregnating polyurethane foam with ceramic slurry, drying, baking and finally firing the foam in the oven. Experimental tests were carried out to the filters to measure dimensions, weight, cold compression strength, and permeability properties before pouring process. After pouring process, the filter was cut into several sections to measure the macro and microstructure of the filter and ensure that impurity particles captured by a filter. Thermal shock properties, obtained from pouring liquid aluminium when filter was placed in the gating system to ensure that the filters could withstand temperatures of aluminium alloys. Further experiments were carried out to investigate and determine the efficiency of produced ceramic foam filter on quality of cast products. The result obtained in this investigation, the mechanical properties for aluminum LM6 alloy sand casting increased when ceramic foam filter was inserted into the gating system. A produced filter by using new materials is economical to be produced. Further more, the analysis data shows present innovation filter which can be made in any shape and size, has excellent thermal shock resistance, adequate compressive strength, acceptable density and permeability properties.