Utilization of wet-handled and dry-handled coal bottom ashes in portland cement based composites

Download

Thesis_Bottom_Ash_SERA-CM_02.pdf

Date

2021-9-7

Author

Tirkeş, Sera

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

114
views

98
downloads

Coal bottom ash (BA) is a coarse, granular, incombustible by-product collected from the bottom of coal-burning furnaces. Traditionally, it has been handled by wet-handling systems (WHS) that use large amounts of water for cooling and conveying BA. WHS relies on established technologies such as impounded hoppers or submerged scraper conveyors. However, the need for water treatment, environmental concerns such as contaminated water, and high operational costs caused a necessary shift from WHS to more sustainable dry-handling systems (DHS) that do not need water and water treatment. Furthermore, returning heat energy to the boiler from the DHS result in lower coal usage. Currently, both handling systems are actively used in thermal power plants. This research focuses on the performance of wet-handled (WH) and dry-handled (DH) BAs in Portland cement-based systems when used as supplementary cementitious material (SCM) or fine aggregate (FA). BAs were collected from two different thermal power units with similar burning systems and operating conditions which burn the same coal. One unit was equipped with WHS and the other with DHS allowing a controlled comparison of the ash handling systems. Both BAs were highly amorphous and had similar chemical compositions; albeit, AHBA was lighter, coarser, more porous, and more grindable. When ground and used as an SCM or sieved and used as FA, both BAs showed comparable compressive and flexural strengths, heat of hydration, and alkali-silica reaction resistivity. Results show that BAs from both ash-handling systems can be efficiently utilized in Portland cement-based systems.

Subject Keywords

Dry-Handled Bottom Ash, Wet-Handled Bottom Ash, Supplementary Cementitious Material, Fine Aggregate, Sustainability

URI

https://hdl.handle.net/11511/94324

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Use of coal ash cement stabilized material as pavement base material: Laboratory characterization and field evaluation Wiranata, Didi Yuda; Yang, Shih-Hsien; Akgül, Çağla; Hsien, Ho Yu; Nugraha, Muhammad Zilzaludin Putra (2022-08-15) © 2022Coal fly ash (CFA) and coal bottom ash (CBA) are coal combustion's primary solid waste products. This solid waste management is a substantial challenge for power plants and local authorities. In order to apply coal ash as a pavement base material, the relationship of the mixture's mechanical properties with structural design parameters for pavement design and analysis must be explored. No study has investigated the mechanical behavior of the 100% coal ash cement stabilized material (CACSM) as a paveme...
Utilization of Yatagan Power Plant Fly Ash in Production of Building Bricks Önel, Öznur; TANRIVERDİ, MEHMET; ÇİÇEK, TAYFUN (2017-09-15) Fly ash is a by-product of coal combustion, which accumulates in large quantities near the coal-fired power plants as waste material. Fly ash causes serious operational and environmental problems. In this study, fly ash from Yatagan thermal power plant was used to produce light-weight building bricks. The study aimed to reduce the problems related to fly ash by creating a new area for their use. The optimum process parameters were determined for the production of real size bricks to be used in construction ...
Usage of aluminum dross for slag treatment in secondary steelmaking to decrease amount of reducible oxides in ladle furnace Geveci, Ahmet (2006-08-31) In this work it is aimed to assess the plant analytical data which appeared during efforts to decrease the effect of carry-over slag (basic oxygen furnace slag) that can not be prevented to leak during tapping of steel in the ladles. While the amount changes, carry-over slag that escaped to ladle, consists of appreciable amount of reducible oxides ("FetO" and MnO) which act as oxygen source for steel bath. By using aluminum dross, containing %30-35 metallic aluminum, which is a non-recoverable process outco...
Utilization of fine coal tailings by flotation using ionic reagents Sis, H; Ozbayoglu, G; Sarikaya, M (Informa UK Limited, 2004-08-01) Fatty acid type ionic collectors were used as an alternative to conventional oily collectors, kerosene, and pine oil mixture in the flotation of coal tailing with 46.1% ash. The conventional collectors could not reduce the ash content of the concentrate below 22%. On the other hand, ionic collectors were found to be significantly better at reducing the ash content down to 13%. It was concluded that despite their lower flotation yield and higher consumptions, certain ionic collectors could be used successful...
Assessment of catalyst deactivation model for sulfur retention in fluidized bed combustors Degirmenci, E; Gogebakan, Y; Selçuk, Nevin (2000-01-01) An improved version of a combustion-desulfurization model for fluidized bed combustors burning high ash and sulfur content low quality lignite in its own ash with the addition of limestone is presented. The desulfurization model considers sulfur retention by both limestone and ash and is based on first order catalyst deactivation where the kinetics of desulfurization is described by two rate constants; one for the initial surface reaction, the other for the rate of pore plugging or deactivation. The accurac...

Citation Formats

S. Tirkeş, “Utilization of wet-handled and dry-handled coal bottom ashes in portland cement based composites,” M.S. - Master of Science, Middle East Technical University, 2021.