scholarly journals Utilization of CFBC Fly Ash as a Binder to Produce In-Furnace Desulfurization Sorbent

2018 ◽  
Vol 10 (12) ◽  
pp. 4854 ◽  
Author(s):  
Chulseoung Baek ◽  
Junhyung Seo ◽  
Moonkwan Choi ◽  
Jinsang Cho ◽  
Jiwhan Ahn ◽  
...  
Keyword(s):  
Fly Ash ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Coal Ash ◽  
Limestone Powder ◽  
Fluidized Bed Combustion ◽  
High Concentration ◽  
Cfbc Fly Ash ◽  
Desulfurization Efficiency ◽  
Free Cao

Circulating fluidized bed combustion (CFBC) power generation technology is known to efficiently reduce the emission of air pollutants, such as SO2 and NO2, from coal combustion. however, CFBC coal ash contains high contents of free CaO, making it difficult to recycle. This research has been conducted to find ways to use the self-hardening property of CFBC coal ash, one of its inherent characteristics. As part of these efforts, the present study intended to investigate the properties and desulfurization efficiency of Ca-based desulfurization sorbents using CFBC fly-ash as a binder. Limestone powder was mixed with CFBC fly-ash and Ca(OH)2 to fabricate desulfurization sorbents, and it generated hydrate of cement, including portlandite, ettringite, and calcium silicate, etc. The compressive strength of the desulfurization absorbent prepared by CFBC fly ash and Ca(OH)2 was 72–92% that of the desulfurized absorbent prepared by using general cement as a binder. These absorbents were then compared in terms of desulfurization efficiency using a high-temperature fluidized bed reactor. It was confirmed that the desulfurization absorbents fabricated using CFBC fly-ash as a binder achieved the best performance in terms of absorption time, which reflects the time taken for them to remove over 90% of high-concentration SO2 gas, and the conversion ratio, which refers to the ratio of CaO turning into CaSO4.

Utilization of Circulating Fluidized Bed Combustion (CFBC) Fly Ash and Coal-Fired Fly Ash in Portland Cement

2014 ◽  
Vol 629-630 ◽  
pp. 306-313 ◽  
Author(s):  
Mao Chieh Chi ◽  
Ran Huang ◽  
Te Hsien Wu ◽  
Toun Chun Fou
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Fluidized Bed ◽  
Building Materials ◽  
Circulating Fluidized Bed ◽  
Setting Time ◽  
Fluidized Bed Combustion ◽  
Initial Setting Time ◽  
Cfbc Fly Ash ◽  
Circulating Fluidized Bed Combustion

Circulating fluidized bed combustion (CFBC) fly ash is a promising admixture for construction and building materials due to its pozzolanic activity and self-cementitious property. In this study, CFBC fly ash and coal-fired fly ash were used in Portland cement to investigate the pozzolanic and cementitious characteristics of CFBC fly ash and the properties of cement-based composites. Tests show that CFBC fly ash has the potential instead of cementing materials and as an alternative of pozzolan. In fresh specimens, the initial setting time of mortars increases with the increasing amount of cement replacement by CFBC fly ash and coal-fire fly ash. In harden specimens, adding CFBC fly ash to replace OPC reduces the compressive strength. Meanwhile, CFBC fly ash would results in a higher length change when adding over 30%. Based on the results, the amount of CFBC fly ash replacement cement was recommended to be limited below 20%.

scholarly journals Utilization of low sulfur fly ash from circulating fluidized bed combustion burner as geopolymer binder

2020 ◽  
Vol 22 (2) ◽  
pp. 94-100
Author(s):  
Antoni Antoni ◽  
Stacia Dwi Shenjaya ◽  
Maria Lupita ◽  
Samuel Santosa ◽  
David Wiyono ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Fluidized Bed ◽  
Water Demand ◽  
Circulating Fluidized Bed ◽  
Fluidized Bed Combustion ◽  
Naoh Solution ◽  
Cfbc Fly Ash ◽  
Low Sulfur ◽  
Circulating Fluidized Bed Combustion

Circulating fluidized bed combustion (CFBC) is a newer type of burner that employ a circulating process to burn fuel effectively. CFBC burning process is gaining more popularity due to its compact size, high efficiency and lower burning temperature compared to the pulverized coal combustion (PCC) burner. The CFBC burner produces fly ash with different physical properties compared to the PCC burner, i.e. the fly ash is not rounded, and required higher water content for comparable workability. The CFBC fly ash also has a high sulfur content that is detrimental for hardened concrete. Due to its drawbacks, the CFBC hardly used as cementitious material and geopolymer precursor. This study focuses on comparing variations in the concentration of NaOH solution and variations in the ratio of alkaline activators to the setting time and compressive strength of geopolymer mortars on a new class of CFBC fly ash, which have low sulfur content. The concentrations of NaOH solution were 6M, 8M, 10M, and 12M, while the alkaline activator ratios used were 3.0, 2.5, 2.0, 1.0, and 0.5. It was concluded that the low sulfur CFBC fly ash has a potential to be utilized as geopolymer precursor, however, with a shortcoming in its high water demand. The CFBC fly ash used in this study resulted in a geopolymer matrix with good compressive strength and stability. The water demand varies with the fly ash sampling time shows the challenges in the utilization of the fly ash. The highest mortar’s compressive strength, 33.4 MPa at 90 days was achieved at NaOH concentration of 8M and ratio of sodium silicate solution to sodium hydroxide solution of 2.5 with excellent stability.

Optimization of the Composition of the Binder Based on CFBC Fly Ash

2018 ◽  
Vol 760 ◽  
pp. 184-192 ◽  
Author(s):  
Petr Formáček ◽  
Rostislav Šulc
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Computer Programs ◽  
Fluidized Bed Combustion ◽  
Slaked Lime ◽  
Cfbc Fly Ash ◽  
Main Components ◽  
Circulating Fluidized Bed Combustion

This paper is bound to previous research of materials based on fly ash. The main objective was to design an optimal ternary (three-component) binder based on fly ash from Circulating fluidized Bed Combustion (CFBC). The design of the binder is based on the optimization of individual components. Main components of the binder are CFBC fly ash, high-temperature fly ash and slaked lime. The binder was progressively designed and optimized. The strength characteristics of the various binders were measured, evaluated and the results were inserted into computer programs Surfer 8 and Grapher 8 from which ternary diagrams with strength maps were created. The best binder mixture were selected from the optimization process.

scholarly journals Highly Effective Adsorption Process of Ni(II) Ions with the Use of Sewage Sludge Fly Ash Generated by Circulating Fluidized Bed Combustion (CFBC) Technology

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3106
Author(s):  
Tomasz Kalak ◽  
Kinga Marciszewicz ◽  
Joanna Piepiórka-Stepuk
Keyword(s):  
Fly Ash ◽  
Sewage Sludge ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Fluidized Bed Combustion ◽  
Nickel Ions ◽  
Suitable Material ◽  
Circulating Fluidized Bed Combustion

Recently, more and more attention has been paid to the removal of nickel ions due to their negative effects on the environment and human health. In this research, fly ash obtained as a result of incineration of municipal sewage sludge with the use of circulating fluidized bed combustion (CFBC) technology was used to analyze the possibility of removing Ni(II) ions in adsorption processes. The properties of the material were determined using analytical methods, such as SEM-EDS, XRD, BET, BJH, thermogravimetry, zeta potential, SEM, and FT-IR. Several factors were analyzed, such as adsorbent dose, initial pH, initial concentration, and contact time. As a result of the conducted research, the maximum sorption efficiency was obtained at the level of 99.9%. The kinetics analysis and isotherms showed that the pseudo-second order equation model and the Freundlich isotherm model best suited this process. In conclusion, sewage sludge fly ash may be a suitable material for the effective removal of nickel from wastewater and the improvement of water quality. This research is in line with current trends in the concepts of circular economy and sustainable development.

scholarly journals Research in the fluidized bed combustion in the Laboratory for thermal engineering and energy - Part A: Achievements in targeted fundamental research

2019 ◽  
Vol 23 (Suppl. 5) ◽  
pp. 1637-1653
Author(s):  
Borislav Grubor ◽  
Dragoljub Dakic ◽  
Stevan Nemoda ◽  
Milica Mladenovic ◽  
Milijana Paprika ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Coal Ash ◽  
Thermal Engineering ◽  
Fluidized Bed Combustion ◽  
Particle Combustion ◽  
Research Activities ◽  
Energy Part ◽  
Char Particle ◽  
Fundamental Research

The paper gives a review of the most important results of extensive targeted fundamental research program on fluidized bed combustion in the Laboratory for Thermal Engineering and Energy of the VINCA Institute of Nuclear Sciences. The paper presents a detailed overview of research activities from the beginning in the second half of the 1970'' up to present days. Starting with the motives for initiating the investigations in this field, the paper highlights various phases of research and points out the main results of all research activities, not only the ones that are focused in this paper. Targeted fundamental research topics that are overviewed in this paper are heat and mass transfer, coal particle fragmentation, char particle combustion, sulfur self-retention by coal ash itself, as well as circulating fluidized bed modeling.

Chemical Properties and Reactivity of CFBC Fly Ash

2016 ◽  
Vol 722 ◽  
pp. 132-139 ◽  
Author(s):  
Tomáš Váchal ◽  
Rostislav Šulc ◽  
Tereza Janků ◽  
Pavel Svoboda
Keyword(s):  
Thermal Properties ◽  
Fly Ash ◽  
Circulating Fluidized Bed ◽  
Chemical Properties ◽  
Total Content ◽  
Calorimetric Measurement ◽  
Fluidized Bed Combustion ◽  
Cfbc Fly Ash ◽  
Circulating Fluidized Bed Combustion ◽  
Methods Of Measurement

This paper describes chemical properties of fly ash from Circulating fluidized Bed Combustion (CFBC). There are shown thermal properties of fly ash using calorimetric measurement and the total content of calcium oxide CaO was determined. This paper describes the methods of measurement for determining these properties including granulometric measurement and chemical analysis. Also there were described and evaluated properties of fly ash and the reactivity of the fly ash was compared.

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