Refuse-Derived Fuel and Integrated Calcium Hydroxide Sorbent for Coal Combustion Desulfurization

Abstract

Pelletized refuse-derived fuel (RDF; 65 wt % nonrecyclable fibers/plastics) and integrated calcium hydroxide sorbent (35 wt %), referred to as a ReEngineered Feedstock (ReEF), were evaluated as a renewable fuel and an in situ sulfur sorbent within pulverized coal combustion. Characterization of ReEF with scanning electron microscopy–energy-dispersive X-ray spectroscopy indicated random distribution of calcium hydroxide sorbents on fiber/plastic particles. The sulfation kinetics of ReEF combustion were evaluated in a drop-tube reactor at variable conditions (800–1000 °C, 1400 ppm of SO2, and 5–30% O2 in N2) with continuous effluent characterization via online IR spectroscopy. Sulfation of calcium hydroxide in ReEF was delayed because of RDF combustion when compared with pure calcium hydroxide sorbent. A low-O2 condition was shown to produce high conversion of calcium hydroxide to calcium sulfate (X Ca(OH)2 > 0.4), while calcination and combustion of ReEF in a high-O2 environment (O2 > 20%) resulted in increased sorbent sintering and reduced total sulfur uptake.

­­­Local electronic structure investigation of the sol-gel processed calcium hydroxide material

“…Calcium hydroxide find applications in dentistry [1], bone treatment [2], conservation of cultural heritage [3,4]. It is also being utilized for desulfurization [5] and CO2 capture [6]. Alcohol dispersion of this materials is helpful to conserve stone [7].…”

“…In addition, this technique also give information about self-induced strain, crystallite size, and microstructural information of synthesized materials [19][20][21]. Not only, structural behavior but morphological investigation is essential for synthesized material since the shape and size play important roles in determining their efficiency for particular application [1][2][3][4][5][6]. Scanning electron microscopy has been identified to investigate morphological behavior of nanoparticles.…”

New Strategy toward Household Coal Combustion by Remarkably Reducing SO2 Emission

“…Ca-based sorbents are the well-known and commonly used sorbents for SO 2 removal from combustion gases because of their wide availability, low price, and high efficiency. − Guan carried out combustion experiments of coal with three kinds of calcium-based sulfur fixing agents (CaO, Ca­(OH) 2 , and CaCO 3 ) and found that Ca­(OH) 2 had a better effect on sulfur fixation and CaCO 3 promoted the release of SO 2 at low temperatures. The CaCO 3 /CaO solid sorbent particle size had a significant effect on SO 2 capture, and mixed solid sorbent had higher capture efficiency than the conventional pure solid sorbent .…”

Effect of Blast Furnace Sludge on SO2 Emissions from Coal Combustion

“…To reduce SO 2 emission, inhibiting SO 2 emissions during coal combustion processes has been the focus to protect the atmospheric environment . Coal sulfur-fixing agents, such as CaCO 3 , CaO, Ca­(OH) 2 , MgCO 3 , MgO, Na 2 CO 3 , and NaOH, are crucial for limiting sulfur dioxide emissions during coal combustion. , Sulfur-fixing agents include calcium-based sorbents (CaCO 3 , CaO, and Ca­(OH) 2 ) and alkaline residues (carbide slag, waste paper, boron mud, natural minerals, and other industrial waste salt and limestone). − The most widely used and cheap sulfur-fixing agents are calcium-based sorbents (CaCO 3 , CaO, and Ca­(OH) 2 ). − Because calcium-based sulfur-fixing products (CaSO 4 ) decompose easily at high temperatures, many scholars have studied the methods for reducing CaSO 4 decomposition at high temperatures and found that the addition of alkali metal oxides or alkaline have efficient effects. For example, Sm-based and Mn-/SBA-15 sulfur-fixing agents can effectively inhibit SO 2 emissions from coal combustion. , In addition, based on the properties of calcium-based sulfur-fixing agents, SiO 2 , CuO, ZnO, Fe 2 O 3 , and other substances have shown certain synergistic effects on sulfur-fixing processes. , Therefore, the studies on the compounds in sulfur-fixing agents have received significant interest in recent years; however, synthetic or natural sulfur-fixing agents have high costs.…”

“…1 Coal sulfur-fixing agents, such as CaCO 3 , CaO, Ca(OH) 2 , MgCO 3 , MgO, Na 2 CO 3 , and NaOH, are crucial for limiting sulfur dioxide emissions during coal combustion. 2,3 Sulfur-fixing agents include calcium-based sorbents (CaCO 3 , CaO, and Ca(OH) 2 ) and alkaline residues (carbide slag, waste paper, boron mud, natural minerals, and other industrial waste salt and limestone). 7−9 The most widely used and cheap sulfurfixing agents are calcium-based sorbents (CaCO 3 , CaO, and Ca(OH) 2 ).…”