Controlling fly ash adhesion at high temperatures via porosity effect

Ito, Masahiro; Horiguchi, Genki; Hariu, Takafumi; Ito, Atsuki; Kamiya, Hidehiro; Okada, Yohei

doi:10.1016/j.powtec.2020.07.057

Cited by 19 publications

(21 citation statements)

References 20 publications

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“…Thus, porosity of the powder beds was increased in the presence of nanoparticles with poor packing ability. This effect had been demonstrated in previous studies. ,,, A previous study demonstrated that the porosity increase upon addition of nanoparticles induced a decrease in the tensile strength of a cohesive powder bed at high temperatures. ,, This phenomenon can be explained by the following Rumpf theory equation: where σ is tensile strength, ε is porosity, x is particle size, and F is attractive force between particles (mainly liquid bridge forces) at high temperatures. The degree of the decrease in tensile strength induced by the porosity increase in the Fe-added P-SiO 2 system was estimated by the theory (calculation details are shown in the Supporting Information).…”

Section: Resultssupporting

confidence: 58%

“…In contrast, no significant difference in porosity of the powder beds of the synthetic ashes was observed. Previously, the porosity of powder beds affected the tensile strength at high temperatures, which made the mechanism of adhesion induced by chemicals difficult to understand. , In the present research with synthetic ashes, a system was constructed to determine only the effect of chemicals (presence of P) on the increase of adhesiveness.…”

Section: Resultsmentioning

confidence: 99%

“…Previously, the porosity of powder beds affected the tensile strength at high temperatures, which made the mechanism of adhesion induced by chemicals difficult to understand. 39,41 In the present research with synthetic ashes, a system was constructed to determine only the effect of chemicals (presence of P) on the increase of adhesiveness. Tensile strengths of the synthetic ashes were measured at 900 °C (Figure 2), and the proportional relation between concentration of P and tensile strength was determined.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…39−41 For sewage sludge incinerated ashes, which contained P at high concentrations, adhesiveness began to increase near 600 °C, a temperature that is lower than that of coal ashes. 40,41 This observation indicated that the adhesiveness of ashes that contain P easily adhere inside the incineration machinery. These provided a promising method for quantifying the adhesiveness of P-containing ashes at high temperatures.…”

Section: ■ Introductionmentioning

confidence: 90%

“…A device to evaluate the adhesiveness of particles at high temperatures was developed previously and could measure the adhesiveness of many types of particulate materials, including combustion and incineration ashes. − An analysis of various ashes revealed that P, Na, and K in ashes increased adhesiveness at high temperatures. − For sewage sludge incinerated ashes, which contained P at high concentrations, adhesiveness began to increase near 600 °C, a temperature that is lower than that of coal ashes. , This observation indicated that the adhesiveness of ashes that contain P easily adhere inside the incineration machinery. These provided a promising method for quantifying the adhesiveness of P-containing ashes at high temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Role of Phosphorus and Iron in Particle Adhesiveness at High Temperatures Using Synthetic Ashes

Horiguchi

Ito

et al. 2021

ACS Sustainable Chem. Eng.

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During sewage treatment, phosphorus (P) is concentrated in sewage sludge, and the sludge is incinerated to produce P-concentrated ash particles. The P-containing ash particles possess high adhesiveness at high temperatures, which can cause problems for the incineration plants. Phosphorus is considered a key element for inducing ash particles adhesiveness; however, the mechanistic details remain unclear. The present study clarified the role of P in particle adhesion at high temperatures using synthetic ashes, which consist of P and Si. The tensile strength of synthetic ash powder beds was quantified using a specially developed device that could estimate adhesiveness of particles at high temperatures. Since synthetic ash has few components compared to incineration ashes collected from commercial incineration plants, evaluating the role of P is easier. Iron (Fe)-containing chemical species are used for water treatment as chemical conditioners, and Fe also is concentrated with P in the sludge-incinerated ashes. To determine the interactions between Fe and P, iron oxide nanoparticles were added to P-containing synthetic ashes and their adhesiveness was evaluated. A small addition of iron oxide nanoparticles significantly decreased the adhesiveness of P-containing synthetic ashes at high temperatures, information that can help to control adhesiveness of sewage sludge-incinerated ashes.

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