Combustion and Emission Characteristics of Coal Logs with Different Binders for Transportation in a Hydraulic Pipeline

Abstract

Cationic emulsified asphalt (CEA) and poly­(vinyl alcohol) (PVA) polymer binding agents may affect the combustion characteristics and pollutant emissions of coal logs shaped for transportation in hydraulic pipelines. Therefore, these characteristics were investigated using thermal analysis as well as a lab-scale fixed-bed combustor, together with those of raw coals. Three raw coals, anthracite, bitumite, and lignite, were selected to produce coal logs. The results of thermal analysis were compared to those of raw coals. Binders made the three coals more prone to be ignited. Binders improved the combustion of coal logs made of anthracite yet worsened the combustion performance of bitumite coal logs. CEA binder ameliorated the combustion performance of coal logs made of lignite. PVA binder slightly worsened the combustion performance of coal logs made of lignite. Different binders had dissimilar effects on the pollutant emissions when burning coal logs made of different coals.

Thermal Tolerance and Compatibility of NaOH–Poly(vinyl alcohol) in Bitumen Emulsification for Improved Flow properties

“…However, the color intensity increased greatly at T t = 200 °C and higher temperatures. There have been numerous earlier studies of the thermal degradation of PVA. ,− These studies have shown that significant thermal degradation of PVA occurs at 200 °C and above. In addition, as shown by the color changes observed in the present study (inset Figure a), Gilman et al studied the decomposition chemistry of PVA through thermal pyrolysis and found that heating PVA above the decomposition temperature (250–400 °C for 30 min) resulted in rapid chain-stripping elimination of H 2 O, which led to color changes and cross-linking when coupled with other decomposition reactions.…”

“…2−6 PVA is a water-soluble polymer with the chemical formula [CH 2 CH-(OH)] n that contains carbon, hydrogen, oxygen, and hydroxyl groups. 7,8 It has the ability to lower interfacial tension and function as a nonionic surfactant; is tolerant to high concentrations of electrolytes (particularly acids); and is compatible with other chemicals such as wax crystal modifiers, pour point depressants, and corrosion inhibitors. 3,9−11 A recently reported study on computationally modeled PVA demonstrated excellent wettability, an important surface active property (due to the −OH functionalities on PVA), hence allowing neighboring molecules to interact.…”

“…Recently, hydrophilic polymeric surfactants, such as poly­(vinyl alcohol) (PVA), have been introduced to reduce the viscosity of heavy oil by dispersion or emulsification, which should facilitate production and transportation. − PVA is a water-soluble polymer with the chemical formula [CH 2 CH­(OH)] n that contains carbon, hydrogen, oxygen, and hydroxyl groups. , It has the ability to lower interfacial tension and function as a nonionic surfactant; is tolerant to high concentrations of electrolytes (particularly acids); and is compatible with other chemicals such as wax crystal modifiers, pour point depressants, and corrosion inhibitors. ,− A recently reported study on computationally modeled PVA demonstrated excellent wettability, an important surface active property (due to the −OH functionalities on PVA), hence allowing neighboring molecules to interact . The color-mapped electrostatic potential for PVA (Figure ), based on its electron density distribution, confirmed the red end of the spectrum as possessing the highest stability for a positive test charge (more favorable to interactions).…”

The Dynamic Characteristics of a Piped Capsule Moving in a Straight Pipeline

“…When t = 0.7 s, the pressure of the rear end face of the piped capsule was close to the upstream pressure, and when the water reached the rear end face, the water-passing section suddenly shrank. Due to the fluid inertia, the separation occurred on the surface of the piped capsule near the rear end face, and a large suction was generated on the surface of the piped capsule in this area [28,29]. Under the action of suction, the water flowed to the annular gap so that the pressure in the annular gap area gradually decreased.…”