Coal Age

APR 2016

Coal Age Magazine - For more than 100 years, Coal Age has been the magazine that readers can trust for guidance and insight on this important industry.

Issue link: https://coal.epubxp.com/i/668539

Contents of this Issue

Navigation

Page 40 of 51

in maintaining and operating paste plants. Paste turns the water "problem" into part of the solution. Paste technology offers several advan- tages that help meet the concerns facing the coal-fired power sector. Works with dry or wet ash: Paste tech- nology can be applied whether any of the three main waste streams (fly ash, bot- t o m a s h , F G D ) a r e i n d r y o r w e t f o r m . This gives it a flexibility that allows for use across a fleet of coal-fired power sta- tions, or in cases where the process at a plant changes. Can use liquid waste as part of the solu- tion: One of the attractions of the paste process is that water is required as part of the recipe — and that water can contain contaminants and still do its job. One of the objectives of the paste process in CCR applications is to maximize the use of water — water that would otherwise need to be treated. Through the paste process, con- stituents of concern, such as mercury, that are present in the wastewater can be immobilized as well as the ash itself. Even the most problematic constituents in the wastewater can be encapsulated. Supports progressive slurry pond clo- sure: The paste mass can be used as a cov- er system for ash ponds to immobilize the slurry, giving potential for progressive clo- sure of those ponds. This has been applied in a hard-rock mining context, but so far we have not yet used it for CCR. In cases where closure of ponds is an objective and the need for paste-making capacity is tem- porary, it might be best to use small, mobile paste plant. For applications where turning ash into paste is a long- term solution, the efficiencies of a larger, more permanent paste installation may be called for. Both mobile and permanent technologies are mature, robust and well established through hard-rock mining applications. o p e r a t i n g i d e a s c o n t i n u e d April 2016 www.coalage.com 39 7KLVSDWHQWHGGHVLJQLQFRUSRUDWHVVORWVDWRSSRVLQJGHJUHHDQJOHVFUHDWLQJD]LJ]DJÁRZ ZKLFKLQFUHDVHVUHWHQWLRQWLPHWKHUHIRUHSURYLGLQJLQFUHDVHGGUDLQUDWHVSHUVTXDUHIRRW 7KHVORWV·RULHQWDWLRQLQUHODWLRQWRWKHPDFKLQH·VPRWLRQKHOSVSUHYHQWSDUWLFOHVIURP EHLQJGULYHQLQWRWKHDSHUWXUHVUHGXFLQJSHJJLQJDQGEOLQGLQJSUREOHPVRIWHQ DVVRFLDWHGZLWKÀQHVL]LQJ 9HFWRU6ORW7HFKQRORJ\HQDEOHV\RXWRVFUHHQDQGGHZDWHUDWDKLJKHU HIÀFLHQF\WKDQWUDGLWLRQDOVORWWHGVFUHHQSDQHOV967DOVRKDVDPXFKORZHU WHQGHQF\WRSOXJZLWKQHDUVL]HGSDUWLFOHVSURYLGLQJKLJKHURSHQDUHD $YDLODEOHLQPPDQGPPDSHUWXUHV&RPLQJVRRQLQDGGLWLRQDODSHUWXUHVL;]HV Call us at 1-864-579-4594 or visit polydeckscreen.com/coal WRÀQGWKH3RO\GHFN5HJLRQDO0DQDJHULQ\RXUDUHD VST panels incorporate slots at opposing 45 degree angles. Fly ash paste desiccates into a hardened mass that can be driven on, landformed and ultimately reclaimed. Seepage and storage capacity were major concerns associated with the slurry disposal of fly ash at this western U.S. site. Since 2004, a paste plant has operated to dewater, transport and deposit the paste fly ash into deposition areas. The fly ash is pozzolanic in nature so the resulting deposit cures within days to support equipment as required and has effectively mitigated the risk of seepage, and has extended the life of the facility to match the life of the power plant. Case Study: Storage of Fly Ash in the Western USA

Articles in this issue

Links on this page

Archives of this issue

view archives of Coal Age - APR 2016