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Title: Characteristics of pneumatically-emplaced dry flue gas desulfurization materials

Abstract

The University of Kentucky in collaboration with the Department of Energy, Addington, Inc. and Costain Coal is currently developing a commercial concept for the haul back of dry flue gas desulfurization materials (FGDM) into highwall mine adits. The University`s Center for Applied Energy Research (CAER) is investigating emplacement systems for a mine demonstration which is planned for the third quarter of 1996. A laboratory-scale transport system has been built at the CAER to evaluate the potential of pneumatic transport for FGDM emplacement. The system is modeled after shotcreting systems in which water is mixed with cement (FGDM) in a nozzle at the end of the pneumatic pipe. Solids travel approximately 70 ft in the lab-scale system at a rate of up to 6 lb FGDM/minute prior to impingement onto a sample collector. Prehydrated FGDM from a circulating fluidized bed combustor has been successfully emplaced onto vertically positioned sample surfaces without excessive dust liberation. The test program is focussed on determining the pneumatic conditions necessary to maximize the strength of the emplaced FGDM under anticipated mine curing conditions while minimizing dust formation. The mineralogy and strength of a pneumatically created sample are described following curing for 60 days.

Authors:
; ; ;  [1]
  1. Univ. of Kentucky, Lexington, KY (United States) [and others
Publication Date:
OSTI Identifier:
430281
Report Number(s):
CONF-960376-
Journal ID: ACFPAI; ISSN 0569-3772; TRN: 97:000004-0009
DOE Contract Number:
FC21-93MC30251
Resource Type:
Journal Article
Resource Relation:
Journal Name: Preprints of Papers, American Chemical Society, Division of Fuel Chemistry; Journal Volume: 41; Journal Issue: 2; Conference: Spring national meeting of the American Chemical Society (ACS), New Orleans, LA (United States), 24-28 Mar 1996; Other Information: PBD: 1996
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; 36 MATERIALS SCIENCE; FLUE GAS; DESULFURIZATION; FLY ASH; WASTE PRODUCT UTILIZATION; MECHANICAL PROPERTIES; COAL; MOISTURE; CURING; MINERALOGY; COAL MINES

Citation Formats

Carter, S.D., Rathbone, R.F., Graham, U.M., and Robl, T.L.. Characteristics of pneumatically-emplaced dry flue gas desulfurization materials. United States: N. p., 1996. Web.
Carter, S.D., Rathbone, R.F., Graham, U.M., & Robl, T.L.. Characteristics of pneumatically-emplaced dry flue gas desulfurization materials. United States.
Carter, S.D., Rathbone, R.F., Graham, U.M., and Robl, T.L.. 1996. "Characteristics of pneumatically-emplaced dry flue gas desulfurization materials". United States. doi:.
@article{osti_430281,
title = {Characteristics of pneumatically-emplaced dry flue gas desulfurization materials},
author = {Carter, S.D. and Rathbone, R.F. and Graham, U.M. and Robl, T.L.},
abstractNote = {The University of Kentucky in collaboration with the Department of Energy, Addington, Inc. and Costain Coal is currently developing a commercial concept for the haul back of dry flue gas desulfurization materials (FGDM) into highwall mine adits. The University`s Center for Applied Energy Research (CAER) is investigating emplacement systems for a mine demonstration which is planned for the third quarter of 1996. A laboratory-scale transport system has been built at the CAER to evaluate the potential of pneumatic transport for FGDM emplacement. The system is modeled after shotcreting systems in which water is mixed with cement (FGDM) in a nozzle at the end of the pneumatic pipe. Solids travel approximately 70 ft in the lab-scale system at a rate of up to 6 lb FGDM/minute prior to impingement onto a sample collector. Prehydrated FGDM from a circulating fluidized bed combustor has been successfully emplaced onto vertically positioned sample surfaces without excessive dust liberation. The test program is focussed on determining the pneumatic conditions necessary to maximize the strength of the emplaced FGDM under anticipated mine curing conditions while minimizing dust formation. The mineralogy and strength of a pneumatically created sample are described following curing for 60 days.},
doi = {},
journal = {Preprints of Papers, American Chemical Society, Division of Fuel Chemistry},
number = 2,
volume = 41,
place = {United States},
year = 1996,
month =
}
  • The University of Kentucky in collaboration with the Department of Energy, Addington Inc. and Costain Coal Inc. is currently developing a commercial concept for the back haul of flue gas desulfurization materials (FGDM) into highwall mine adits. A laboratory-scale transport system is being used to evaluate the potential of pneumatic transport for FGDM emplacement. The system is modeled after shotcreting systems in which water is mixed with air-transported cement (FGDM) in a nozzle at the end of the pneumatic pipe. Excellent emplacement characteristics of the FGDM have been observed in the laboratory using this technique. The development of cementitious bondsmore » to produce strength equivalent to coal is essential to maximize the success of this commercial back-haul scenario. This paper examines the changing mineralogic composition by XRD and SEM during curing of pneumatically emplaced FGDM. Relationships between material strength and chemical composition as a function of curing time, CO{sub 2} exposure, and weathering conditions will also be discussed.« less
  • The semidry flue gas desulfurization (FGD) process has many advantages over the wet FGD process for moving sulfur dioxide emissions from pulverized coal-fired power plants. Semidry FGD with a rapidly hydrated sorbent was studied in a pilot-scale circulating fluidized bed (CFB) experimental facility. The sorbent was made from lumps of lime and coal fly ash. The desulfurization efficiency was measured for various operating parameters, including the sorbent recirculation rate and the water spray method. The experimental results show that the desulfurization efficiencies of the rapidly hydrated sorbent were 1.5-3.0 times higher than a commonly used industrial sorbent for calcium tomore » sulfur molar ratios from 1.2 to 3.0, mainly due to the higher specific surface area and pore volume. The Ca(OH){sub 2} content in the cyclone separator ash was about 2.9% for the rapidly hydrated sorbent and was about 0.1% for the commonly used industrial sorbent, due to the different adhesion between the fine Ca(OH){sub 2} particles and the fly ash particles, and the low cyclone separation efficiency for the fine Ca(OH){sub 2} particles that fell off the sorbent particles. Therefore the actual recirculation rates of the active sorbent with Ca(OH){sub 2} particles were higher for the rapidly hydrated sorbent, which also contributed to the higher desulfurization efficiency. The high fly ash content in the rapidly hydrated sorbent resulted in good operating stability. The desulfurization efficiency with upstream water spray was 10-15% higher than that with downstream water spray. 20 refs., 7 figs., 1 tab.« less
  • Life-cycle cost analyses of the use of stainless steels (SSs) and other corrosion-resistant alloys were compared with those of lined carbon steel in the construction of flue gas desulfurization components. The life-cycle cost analysis included all of the cost components that are affected by the materials of construction and was based on standard costing procedures followed by the utility industry. Although the capital costs for SS and corrosion-resistant alloys are generally higher than those of the lined carbon steel components, the life-cycle costs are less in most cases. Additional benefits include improved reliability and reduced downtime. Savings can be furthermore » increased by optimizing the selection of materials for individual components by matching the operating environment of the component and mechanical characteristics of the materials. Extensive field experience confirms the favorable conclusions of the study.« less
  • The flue gas environment in coal-fired power plants using flue gas desulphurization is first examined. Various construction materials for FGD systems are evaluated in relation to their resistance to the types of corrosion likely to be encountered.
  • The cyclic heat process consists of removing heat from the hot gases ahead of the scrubber and returning this heat to the flue gas downstream of the scrubber before it enters the stack. Of the various approaches to cyclic reheat, the gas-liquid-gas heat exchange system has received the most emphasis in the US. In this concept, a heat extractor in the scrubber inlet duct transfers heat to a working fluid which is circulated through a heater unit in the scrubber outlet duct. When the boiler is operated with a high-sulfur coal, the temperature of the heat extractor unit is belowmore » the dewpoint of sulfuric acid in the flue gas, so the unit must be made of corrosion resistant material. A field exposure program is being conducted in which various materials are exposed to the flue gas from a washed Illinois No.5 coal (containing 2-3% S) at the Scholz Steam Plant of Gulf Power Company. The materials investigate to date have included: (1) austenitic, ferritic, and duplex stainless steels, (2) nickel-base alloys, (3) alloys of zirconium and titanium. Carbon steel and cast iron were used for comparison purposes, although substantial wastage was anticipated. Non-metallic materials evaluated comprised polymeric coatings and porcelainized ceramics applied to carbon steel and Pyrex glass. This paper presents and discusses the results of the material testing. 2 figures.« less