Enhanced biodiesel production from diseased swine fat by ultrasound-assisted two-step catalyzed process.

In order to enhance the yield of high quality biodiesel form diseased swine fat, the ultrasound-assisted two-step catalyzed process was employed. First, three-dimensional ultrasound-assisted concentrated sulfuric acid pre-esterification experiment was carried out. Then, the transesterification reaction catalyzed by KOH was performed, and four parameters (catalyst concentration, reaction time, methanol/oil molar ratio and reaction temperature) were optimized using response surface methodology. The results showed that the optimal transesterification reaction conditions were catalyst concentration of 1.11 wt%, reaction temperature of 62.3 °C, methanol/oil molar ratio of 7.42:1, and reaction time of 116.14 min. The most significant factor affecting biodiesel purity was identified as catalyst concentration. Under the optimal conditions, the maximum biodiesel purity reached to 98% with the reaction time of 176.14 min, shortened by 63.3% compared with previous works. Furthermore, most of the biodiesel properties agreed the quality requirements established by Official Regulations of GB/25199-2017 of China.

Experimental study on the relationship between the mineral production capability and the physiochemical properties in the coproduction of Q phase-3CaO·3Al2O3·CaSO4 cement clinker.

A coproduction tests of quaternary (Q) phase(6CaO·4Al2O3·MgO·SiO2) -3CaO·3Al2O3·CaSO4 cement clinker and an experimental study on the relationship between the mineral production capability and the physiochemical properties are conducted in a two-stage multiphase reaction test bed with Changguang coal. X-ray diffractometer (XRD) analyses are performed on the coproduction clinker samples. The results demonstrate that, with the reduction in particle sizes of the coal powder and the additives and expanded screening level differences between them, both the proportion of Q phase and the mass of 3CaO·3Al2O3·CaSO4 in the clinker increase accordingly. When mixed coal powder particles are prepared through reducing particle sizes and expanding screening level differences between coal powder and additives, the additives CaO and MgO are more likely to be enclosed by coal powder to form globular polymerized particles. In addition, this preparation aids in polymerization and promotes even distribution of CaO, MgO and coal minerals, thus facilitating clinker mineral formation reactions of inorganic substances in the mixed coal powder. Target minerals, such as 2CaO·SiO2 and Q phase, are found in both industrial high-calcium limestone and low-calcium limestone coproduction clinker samples. A diffraction peak of free CaO is also evident in both samples. Compared with a coproduction clinker sample of high-calcium limestone, that of low-calcium limestone exhibits higher diffraction peaks for 2CaO·SiO2 and Q phase. With the current state of the art, it is not yet the optimum choice to substitute CaCO3 for CaO in Q-phase cement clinker coproduction. Before the technology matures and gains practical application, further study on the form and the mixing process of calcium-based additives for cement clinker coproduction will be required.