1、附录 外文文献及翻译 Utilization of CFB Fly Ash for Construction Applications R. E. Conn and K. Sellakumar Foster Wheeler Development Corporation Livingston, NJ A. E. Bland Western Research Institute Laramie, WY ABSTRACT Disposal in landfills has been the most common means of handling ash incirculating fluidi
2、zedbed (CFB) boiler power plants. Recently, larger CFB boilers with generating capacities up to 300MWe are currently being planned, resulting inincreased volumes and disposal cost of ash byproduct.Studies have shown that CFB ashes do not pose environmental concerns that shouldsignificantly limit the
3、ir potential utilization. Many uses of CFB ash are being investigated by FosterWheeler, which can provide more cost-effective ash management. Construction applications have been identified as one of the major uses for CFB ashes. Typically,CFB ash cannot be used as a cement replacement in concrete du
4、e to its unacceptably high sulfurcontent. However, CFB ashes can be used for other construction applications that require lessstringent specifications including soilstabilization, road base, structural fill, and synthetic aggregate.In this study, potentialconstruction applications were identified fo
5、r fly ashes from several CFBboilers firing diverse fuels such as petroleum coke, refuse derived fuel (RDF) and coal. Thecompressive strength of hydrated fly ashes was measured in order to screen theirpotential for usein various construction applications. Based on the results of this work, the effect
6、s of both ashchemistry and carbon content on utilization potential were ascertained. Actual beneficial uses ofashes evaluated in this study are also discussed. INTRODUCTION CFB combustion has developed into a mature technology for burning a wide range of fuels, whilestill achieving strict air emissi
7、ons requirements. Typically, fuels are burned in a CFB boiler with theaddition of limestone to capture SO2 in a solid form. With larger CFB boilers being brought online,a greater emphasis has been placed on enhanced beneficial use of ash than in the past. Studies haveshown that theenvironmental impa
8、ct from CFB ashes is less than those from p.c. ashes and shouldnot limit their utilization as marketable by-products (Conn and Sellakumar, 1997； Young, 1996). Traditionally, p.c. fly ash has often been sold for use as an admixture in the production ofPortland cement. The utilization options for CFB
9、ashes are somewhat more diverse than p.c. ash,due to the effect of sorbent (calcium) on the overall ash chemistry. These options includeagricultural applications, construction applications and waste treatment. Beneficial use for construction purposes is one of the most common markets for CFB ash. Th
10、eseuses include soil stabilization, road base, structural fills, and synthetic aggregate. To qualify forthese uses, the ash must have special properties and passcertain ASTM tests. Compressive strengthis one of the most important physical properties a material must possess when being considered ford
11、ifferent construction applications. Depending upon the specific application, different degrees of compressive strength are required.In this study, the unconfined compressive strength was measured for hydrated CFB fly ashes fromboilers firing a wide range of fuels. These results provided a indication
12、 of potential construction usesfor fly ashes with very different compositions. The specific objectives of this work were: CHARACTERIZATION OF FLY ASHES Nine fly ashes evaluated in this study were obtained from CFB boilers firing diverse fuels suchas bituminous gob (0.5% S), low volatile bituminous c
13、oal (0.3% S), high sulfur (4.7%) bituminouscoal, petroleum coke (5.0% S), and RDF (0.3% S). The fly ashes had significantly different chemical compositions as wouldbe expected considering the types of fuels being fired. The bituminous gob fly ash was composedprimarily of coal ash since it was taken from a boiler that does not use limestone injection for sulfurcapture.
