skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Evaluation of fly ash from co-combustion of coal and petroleum coke for use in concrete

Abstract

An investigation of fly ash (FA) produced from various blends of coal and petroleum coke (pet coke) fired at Belledune Generating Station, New Brunswick, Canada, was conducted to establish its performance relative to FA derived from coal-only combustion and its compliance with CSA A3000. The FA samples were beneficiated by an electrostatic separation process to produce samples for testing with a range of loss-on-ignition (LOI) values. The results of these studies indicate that the combustion of pet coke results in very little inorganic residue (for example, typically less than 0.5% ash) and the main impact on FA resulting from the co-combustion of coal and up to 25% pet coke is an increase in the unburned carbon content and LOI values. The testing of FA after beneficiation indicates that FA produced from fuels with up to 25% pet coke performs as good as FA produced from the same coal without pet coke.

Authors:
;
Publication Date:
OSTI Identifier:
20885714
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACI Materials Journal; Journal Volume: 104; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; WASTE PRODUCT UTILIZATION; FLY ASH; COCOMBUSTION; COAL; PETROLEUM PRODUCTS; COKE; CONCRETES; CARBON; ELECTROSTATIC SEPARATION

Citation Formats

Scott, A.N., and Thomas, M.D.A. Evaluation of fly ash from co-combustion of coal and petroleum coke for use in concrete. United States: N. p., 2007. Web.
Scott, A.N., & Thomas, M.D.A. Evaluation of fly ash from co-combustion of coal and petroleum coke for use in concrete. United States.
Scott, A.N., and Thomas, M.D.A. Mon . "Evaluation of fly ash from co-combustion of coal and petroleum coke for use in concrete". United States. doi:.
@article{osti_20885714,
title = {Evaluation of fly ash from co-combustion of coal and petroleum coke for use in concrete},
author = {Scott, A.N. and Thomas, M.D.A.},
abstractNote = {An investigation of fly ash (FA) produced from various blends of coal and petroleum coke (pet coke) fired at Belledune Generating Station, New Brunswick, Canada, was conducted to establish its performance relative to FA derived from coal-only combustion and its compliance with CSA A3000. The FA samples were beneficiated by an electrostatic separation process to produce samples for testing with a range of loss-on-ignition (LOI) values. The results of these studies indicate that the combustion of pet coke results in very little inorganic residue (for example, typically less than 0.5% ash) and the main impact on FA resulting from the co-combustion of coal and up to 25% pet coke is an increase in the unburned carbon content and LOI values. The testing of FA after beneficiation indicates that FA produced from fuels with up to 25% pet coke performs as good as FA produced from the same coal without pet coke.},
doi = {},
journal = {ACI Materials Journal},
number = 1,
volume = 104,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • Current US national standards for using fly ash in concrete (ASTM C618) state that fly ash must come from coal combustion, thus precluding biomass-coal co-firing fly ash. The co-fired ash comes from a large and increasing fraction of US power plants due to rapid increases in co-firing opportunity fuels with coal. The fly ashes include coal fly ash, wood fly ash from pure wood combustion, biomass and coal co-fired fly ash SW1 and SW2. Also wood fly ash is blended with Class C or Class F to produce Wood C and Wood E. Concrete samples were prepared with fly ashmore » replacing cement by 25%. All fly ash mixes except wood have a lower water demand than the pure cement mix. Fly ashes, either from coal or non coal combustion, increase the required air entraining agent (AEA) to meet the design specification of the mixes. If AEA is added arbitrarily without considering the amount or existence of fly ash results could lead to air content in concrete that is either too low or too high. Biomass fly ash does not impact concrete setting behaviour disproportionately. Switch grass-coal co-fired fly ash and blended wood fly ash generally lie within the range of pure coal fly ash strength. The 56 day flexure strength of all the fly ash mixes is comparable to that of the pure cement mix. The flexure strength from the coal-biomass co-fired fly ash does not differ much from pure coal fly ash. All fly ash concrete mixes exhibit lower chloride permeability than the pure cement mixes. In conclusion biomass coal co-fired fly ash perform similarly to coal fly ash in fresh and hardened concrete. As a result, there is no reason to exclude biomass-coal co-fired fly ash in concrete.« less
  • The chemistry, mineralogy, morphology, and particle size distribution were investigated in fly ashes from the burning of Datong (ShanXi, China) bituminous coal and the cofiring of Mideast high-sulfur petroleum coke (PC) with 30:70 (cal %) and 50:50 (cal %) blends of Datong bituminous coal in two commercial CFBC boilers. With the exception of CaO, the amounts of major oxides in the fly ashes from cofiring PC and coal were close to those of the common coal fly ashes. The PC-coal fly ashes were enriched in Ni, V, and Mo, implying these trace elements were mainly derived from PC. Ni andmore » V, along with several other elements, such as Cr, Cu, Se, Pb, U, Th, and possibly As and Cd, increased in content with a decrease in temperature of the electrostatic precipitator (ESP). The results of chemistry, mineralogy, and morphology studies suggested that the desulfurization rate of the CFBC boilers at current conditions was low, and the PC tends to coarsen the fly ash particles and increase the loss on ignition (LOI) values, making these fly ashes unsuitable for use as a cement additive or a mineral admixture in concrete. Further studies on the combustion status of the CFBC boilers are needed if we want to be able to increase the desulfurization rate and produce high-quality fly ashes for broader and full utilization. 22 refs., 4 figs., 4 tabs.« less
  • Self-cementitious properties of fly ash from circulating fluidized bed combustion boiler co-firing coal and high-sulphur petroleum coke (CPFA) were investigated. CPFA was self-cementitious which was affected by its fineness and chemical compositions, especially the contents of SO{sub 3} and free lime (f-CaO). Higher contents of SO{sub 3} and f-CaO were beneficial to self-cementitious strength; the self-cementitious strength increases with a decrease of its 45 {mu}m sieve residue. The expansive ratio of CPFA hardened paste was high because of generation of ettringite (AFt), which was influenced by its water to binder ratio (W/A), curing style and grinding of the ash. Themore » paste cured in water had the highest expansive ratio, and grinding of CPFA was beneficial to its volume stability. The hydration products of CPFA detected by X-ray diffraction (XRD) and scanning electron microscopy (SEM) were portlandite, gypsum, AFt and hydrated calcium silicate (C-S-H)« less
  • To develop combustion technology for upgrading the quality of fly ash, the influences of the coal properties, such as the size of pulverized coal particles and the two-stage combustion ratio during the combustion, on the fly ash properties were investigated using our test furnace. The particle size, density, specific surface area (obtained by the Blaine method), and shape of fly ash particles of seven types of coal were measured. It was confirmed that the size of pulverized coal particles affects the size of the ash particles. Regarding the coal properties, the fuel ratio affected the ash particle size distribution. Themore » density and shape of the ash particles strongly depended on their ash size. Our results indicated that the shape of the ash particles and the concentration of unburned carbon affected the specific surface area. The influence of the two-stage combustion ratio was limited. 8 refs., 13 figs., 3 tabs.« less