Regulation of Ash Fusibility Characteristics for High-Ash-Fusion-Temperature Coal by Bean Straw Addition

Abstract

The effects of bean straw (BS) on ash fusion behaviors of coals (Jiaozuo (JZ) and Zaozhuang (ZZ)) with high ash fusion temperature (AFT) and the regulating mechanism were investigated from the perspectives of ash chemical composition and mineralogical property. The results showed that the AFT of JZ ash mixture decreased as the BS ash mass ratio increased, while the AFT of the ZZ ash mixture decreased rapidly (0−12%) and then increased slowly (>12%). The existence form of Al 2 O 3 and SiO 2 was converted from high-melting-point (high-MP) mullite into low-melting-point (low-MP) aluminosilicates and their eutectics with BS ash addition, leading to a decrease in AFT. With increasing BS ash ratio, the major mineral reducing the AFT was changed from feldspar into leucite. Magnesia spinel had a weaker effect on improving the AFT than that of mullite or quartz, because of their different molecular structures. The experimental ash samples were divided into three categories, based on the total contents of SiO 2 and Al 2 O 3 (A): I, A ≥ 78.6%; II, 72.2% ≤ A< 78.6%; and III, 62.7% ≤ A < 72.2%. As the A content decreased, the existing form of Na 2 O and K 2 O was transformed from feldspar into leucite and nepheline; the CaO, together with some FeO and MgO, was transformed from anorthite or cordierite into the more easily fusible melilite and clinopyroxene.

Investigation on Ash-Fusion Characteristics of Livestock Manure and Low-Rank Coals

“…With an increase in the bean straw mass ratio, the AFT of the mixed Jiaozuo coal decreased, whereas the AFT of the mixed Zaozhuang coal decreased rapidly (0−12%) and then increased slowly (>12%). 16 The AFT curves for a mixture of Neimongol coal and bean straw showed a "bathtub"-shaped trend with an increase in the bean straw mass ratio, 17 and the ash structure was transferred from an unmelted to adhered state, and then to severe agglomeration. 18 The flow temperature (FT) variations of the mixed coal differed with an increase in the three crop straw mass ratios (rice, cotton, and corn), and rice straw addition resulted in an increase in FT of the Yulin bitumite ash.…”

“…The AFCs of the coal/biomass mixture differ from that of pure fuel. With an increase in the bean straw mass ratio, the AFT of the mixed Jiaozuo coal decreased, whereas the AFT of the mixed Zaozhuang coal decreased rapidly (0–12%) and then increased slowly (>12%) . The AFT curves for a mixture of Neimongol coal and bean straw showed a “bathtub”-shaped trend with an increase in the bean straw mass ratio, and the ash structure was transferred from an unmelted to adhered state, and then to severe agglomeration .…”

“…Recently, many papers have been published on the AFC of coal and biomass mixtures, and most biomass was derived from agriculture residues (e.g., straw, bean stalk, − corn or cotton stalk, − rice stalk, and peanut hull) and forestry residues (e.g., bamboo, chestnut shell, and pine sawdust). However, investigations of the AFCs of mixtures of Chinese LRC and livestock manure are lacking.…”

Ash analyses of bio-coal briquettes produced using blended binder

“…It was reported that increased quartz content of the ash and high-melting-point mullite generation resulted in a decreased mass of ash deposition of the straw with an increased mass ratio of lignite. Ma et al 37 also attempted regulating the ash fusion characteristics of high AFT coal by adding bean straw. The bean straw was reported to effectively reduce the AFTs of Jiaozuo and Zaozhuang coals for its numerous basic components.…”

Influence of the Direct Coal Liquefaction Residue on the Fusion Characteristics of Jincheng Coal with a High Ash Fusion Temperature

“…Coal is a high-pollution energy resource compared with oil and natural gas; hence, the future development of coal must take the road of high technology and low pollution, and coal gasification is an important way to realize it. Coal gasification technology as the foundation of the modern coal chemical industry can be divided into three categories: fixed bed, fluidized bed, and entrained flow bed. − Nowadays, the entrained flow bed gasification technology is the main stream, , but its liquid slag discharge process generally requires the ash flow temperature (FT) to be less than 1400 °C. − In China, the coal with FT above 1400 °C accounts for about 57% of the total, hence it is necessary to adjust its FT . The ash fusion temperature (AFT) includes the deformation temperature (DT), softening temperature (ST), hemispherical temperature (HT), and FT.…”