Zhicheng Zhao

Effect of methyl acetoacetate as a potential cold flow improver for biodiesel

ABSTRACT This investigation was conducted to determine the cold flow properties of waste cooking oil biodiesel with methyl acetoacetate (MAA) as a potential flow improver. Now, 0.0 vol%, 2.5 vol%, 5.0 vol%, 7.5 vol%, 10 vol%, 15 vol%, and 20 vol% MAA were added to study the effects on the cold flow properties of waste cooking oil biodiesel. The results indicated that the filter plugging point, pour point (PP), and cold point (CP) were decreased by 5°C, 5°C, and 7°C, respectively, after being treated with 20 vol% MAA. Other fuel properties were also determined and compared with ASTM D6571. Additionally, the performance mechanism was explored by differential scanning calorimetry and polarizing microscopy.

Preparation of nitrogen-doped porous carbons for high-performance supercapacitor using biomass of waste lotus stems

In this study, advanced nitrogen-doped porous carbon materials for supercapacitor was prepared using low-cost and environmentally friendly waste lotus stems (denoted as LS-NCs). Nitrogen in the surface functionalities of LS-NCs was investigated using X-ray photoelectron spectroscopy analysis. The sum of pyridine nitrogen (N-6) and pyrrolic/pyridinic (N-5) contents accounted for 94.7% of the total nitrogen and significantly contributed to conductivity. Pore structure and surface area of activated carbons were measured using the Brunauer–Emmett–Teller method. A maximum specific surface area of 1322 m2 g−1 was achieved for LS-NCs. The porous carbons exhibited excellent electrochemical properties with a specific capacitance of 360.5 F g−1 at a current density of 0.5 A g−1 and excellent cycling stability (96% specific capacitance retention after 5000 cycles). The above findings indicate that taking advantage of the unique structure of abundant waste lotus stem provides a low-cost and feasible design for high-performance supercapacitors.

Regeneration of used rolling oil for sustainable use

ABSTRACT In this paper, flocculation and adsorption have been used as an efficient combination for the regeneration of used rolling oil. Polyethyleneimine (PEI) incorporated with polyacrylamide (PAM) as flocculant for treating used rolling oil was examined. The effect of dosages of PEI and PAM was investigated experimentally. The research of a percolation refined adsorption process using different adsorbent materials (silica gel, alumina, and activated carbon) was evaluated. The physical properties and hydrocarbon composition of regenerate oil become similar to the base rolling oil. In addition, the flocculation and adsorption mechanism was also explored.

The influence of polymethyl acrylate as a pour point depressant for biodiesel

ABSTRACT Waste cooking oil biodiesel (BWCO) was used to investigate the influences of polymethyl acrylate (PMA) pour point depressant mixed with common dispersants on the cold flow property of biodiesel. Results showed that PMA mixed with Span80 dispersant at a mass ratio of 2:1 exhibited the best synergistic effect on reducing the cold filter plugging point (CFPP) by 7°C with respect to pure biodiesel. Performance mechanisms were also explored and showed that mixed improvers have better dissolution and dispersion in biodiesel, effectively inhibited the formation of larger crystals, and reduced the amount and sizes of crystals, thereby improving the cold flow properties of biodiesel.