Qingling Liu

Biodiesel production process from microalgae oil by waste heat recovery and process integration

In this work, the optimization of microalgae oil (MO) based biodiesel production process is carried out by waste heat recovery and process integration. The exergy analysis of each heat exchanger presented an efficient heat coupling between hot and cold streams, thus minimizing the total exergy destruction. Simulation results showed that the unit production cost of optimized process is 0.592

Evaluation of hydrolysis–esterification biodiesel production from wet microalgae

/L biodiesel, and approximately 0.172

Intensification of microalgae drying and oil extraction process by vapor recompression and heat integration

/L biodiesel can be avoided by heat integration. Although the capital cost of the optimized biodiesel production process increased 32.5% and 23.5% compared to the reference cases, the operational cost can be reduced by approximately 22.5% and 41.6%.

Oxidation of acetone over Co-based catalysts derived from hierarchical layer hydrotalcite: Influence of Co/Al molar ratios and calcination temperatures

Wet microalgae hydrolysis-esterification route has the advantage to avoid the energy-intensive units (e.g. drying and lipid extraction) in the biodiesel production process. In this study, techno-economic evaluation of hydrolysis-esterification biodiesel production process was carried out and compared with conventional (usually including drying, lipid extraction, esterification and transesterification) biodiesel production process. Energy and material balance of the conventional and hydrolysis-esterification processes was evaluated by Aspen Plus. The simulation results indicated that drying (2.36MJ/L biodiesel) and triolein transesterification (1.89MJ/L biodiesel) are the dominant energy-intensive stages in the conventional route (5.42MJ/L biodiesel). By contrast, the total energy consumption of hydrolysis-esterification route can be reduced to 1.81MJ/L biodiesel, and approximately 3.61MJ can be saved to produce per liter biodiesel.

Transformation of Lignin and Its Model Compounds into Value-Added Chemicals Using Sulfide Catalysts

Reducing energy penalty caused by drying and oil extraction is the most critical challenge in microalgae biodiesel production. In this study, vapor recompression and heat integration are utilized to optimize the performance of wet microalgae drying and oil extraction. In the microalgae drying stage, the hot exhaust stream is recompressed and coupled with wet microalgae to recover the condensate heat. In the oil extraction stage, the exergy rate of recovered solvent is also elevated by compressor and then exchanged heat with feed and bottom stream in the distillation column. Energy and mass balance of the intensified process is investigated and compared with the conventional microalgae drying-extraction process. The simulation results indicated that the total energy consumption of the intensified process can be saved by 52.4% of the conventional route.

Optimization of steam methane reforming coupled with pressure swing adsorption hydrogen production process by heat integration

In order to enhance catalytic performance for acetone, Co-based catalysts prepared under different Co/Al molar ratios and calcination temperatures have been studied in this work. The results indicated that the catalytic activities of the catalysts firstly increased and then decreased with the increase of the Co/Al molar ratio and decreased with the increase of the calcination temperature. Based on the catalytic activities, TG/DTA, XRD, TPR and XPS characterization results, it can be found that catalytic activities of the catalysts with various Co/Al molar ratios were effected by the good crystallization structure of catalyst precursor, surface Co3+/Co2+ molar ratio, low temperature reducibility, and Oads/Olatt molar ratio of the catalysts. Meanwhile, the catalytic activities of the catalysts with different calcination temperatures depended on the low temperature reducibility, surface Co3+/Co2+ molar ratio, porous structure and crystallization structure of the catalyst. Among different synthetic composition, 5:1 CoAlO-300 catalyst (T90% = 225 °C) and 5:1 CoAlO-200 catalyst (T90% = 222 °C) exhibited the efficient acetone oxidation.

Reducing the energy consumption of membrane-cryogenic hybrid CO2 capture by process optimization

Lignin is mainly composed of hydroxy-substituted or methoxylated phenyl propane structures and serves as the only renewable bulk feedstock in nature for producing aromatic chemicals. By using suitable catalysts, the long chain structures of lignin can be selectively broken down to obtain different target products. This has been regarded as an important approach for the comprehensive utilization of lignin. Due to the high activity of hydrodeoxygenation, transition metal sulfide catalysts have been used in lignin conversion in recent decades. In this review, the application of transition metal sulfide catalysts in the catalytic conversions of lignin and its model compounds are summarized. The active components, support materials, reaction conditions and reaction mechanism are presented in detail. The existing challenges of sulfide catalysts in the degradation of lignin are discussed. Finally, potential solutions and future trends of this field are presented.