Fouling and Slagging Characteristics during Co-combustion of Coal and Biomass

Abstract

The effects of different kinds (cotton stalk, rice husk, and sawdust) and proportions (0%, 10%, 20%, and 30% based on weight) of biomass and operating conditions (temperature and excess air coefficient) were evaluated relative to the ash deposition characteristics during the cofiring of Huang Ling (HL) coal with biomass. The experiments were performed in a drop-tube furnace. The chemical compositions and mineral phase characteristics of the collected ash particles were analyzed using scanning electron microscopy with energy dispersive Xray (SEM-EDX) and X-ray diffraction (XRD), respectively. The results showed that the most severe agglomeration, from co-firing coal with cotton stalk, was due to the higher content of alkali metals, especially K. The amount of K in the ash increased with an increasing proportion of cotton stalk, and ultimately, agglomeration was more serious. When the combustion temperature increased from 1050 °C to 1300 °C, the dystectic solid compounds were transformed into eutectic compounds. The increased excess air coefficient accelerated the sulfur reaction, but did not relieve the heavy sintering. Consequently, limiting the content of biomass in the fuel blends, maintaining a lower combustion temperature, and a suitable level of excess air were determined to be necessary for the co-firing of coal and biomass.

Pyrolysis kinetics behavior and pyrolysate compositions analysis of agriculture waste toward the production of sustainable renewable fuel and chemicals

“…significant reduction in fouling and slagging within the boiler or furnace. 26 The fixed carbon content is 22.08%, somewhat greater than the other stated biomass in Table 3 owing to biochemical structural variances. SCB had 46.84% carbon, 6.50% hydrogen, 45.78% oxygen, 0.69% nitrogen, and 0.19% sulfur, which corresponded well with other published feedstock in Table 3.…”

Fine Ash Formation and Slagging Deposition during Combustion of Silicon-Rich Biomasses and Their Blends with a Low-Rank Coal

“…For all of the tests, the sample was fed into the furnace at a rate of 0.2 g/min through a water-cooled injector and burned in synthetic air (79% N 2 and 21% O 2 , with a purity of 99.99%). The furnace temperature was selected as 1300 °C, which is comparable to realistic conditions and widely used in previous studies. ,, This temperature was achieved by electrical heating. The actual constant temperature zone was about 1.2 m. After combustion, the particle-laden flue gas was directed through an isokinetic sampling probe with water cooling and quenched by N 2 .…”

“…The furnace temperature was selected as 1300 °C, which is comparable to realistic conditions and widely used in previous studies. 14,23,24 This temperature was achieved by electrical heating. The actual constant temperature zone was about 1.2 m. After combustion, the particle-laden flue gas was directed through an isokinetic sampling probe with water cooling and quenched by N 2 .…”

“…A study by Al-Naiema et al 13 showed that, in comparison to a low-silicon wood (10% SiO 2 in the ash), co-combustion of a silicon-rich oat hull (64% SiO 2 in the ash) with coal could significantly reduce PM emissions. Zhu et al 14 investigated the ash fouling and slagging during co-combustion of coal and three kinds of biomasses. The results showed that there was no obvious sintering and agglomeration during co-firing rice husk (91% SiO 2 in the ash).…”

Combustion characteristics of cattle manure and pulverized coal co-firing under oxy-fuel atmosphere in non-isothermal and isothermal conditions

“…Therefore, the blending ratio is an important parameter related to the combustion efficiency of the livestock and poultry manure. However, there are conflicting reports on the effects of the blending ratio in the biomass and coal co-firing (Kim et al 2015;Yurdakul 2016;Junga et al 2017;Zhu et al 2017). Detecting the effective mechanism of the blending ratio on combustion is an important issue for optimizing the combustion process.…”