Biodiesel produced from vegetable oil has recently increased in popularity. However, these edible feedstocks (which are the apparent choice of triglycerides) will not be sufficiently sustainable, given the increasing demand for energy and food, and guaranteed inedible feedstocks are needed. Biodiesel can be generated from these alternative feedstocks using various catalysts. Current studies show that nanocatalysts are extensively used for this purpose and are more preferred than usual homogeneous and heterogeneous catalysts. These nanocatalysts exhibit many advantageous features, including efficient separation steps for both products and catalysts, elimination of the quenching process, high catalytic activity, and large surface area, and provide the possibility for reusability. According to recent reports, the use of nonedible oils and nanocatalysts, such as titanium-doped zinc oxide, magnesium oxide-doped magnesium aluminate, zirconium oxide and many others, are potent with an approximately 80-98 wt% yield of biodiesel under optimized conditions, suggesting that this approach is a suitable option for biodiesel synthesis. This review aims to explore the potency of nonedible feedstocks and nanocatalysts for fatty acid methyl ester synthesis. The findings of the most recent published studies are critically summarized. The catalytic reaction mechanism for biodiesel production is highlighted, focusing on the nanocatalysts. Some nonedible seeds have been reported, and their potency for biodiesel production has been assessed in detail.

C20H14N6NiS4, triclinic, P (1) over bar (no. 2), a = 8.519(3) angstrom, b = 8.5956(16) angstrom, c = 8.6531(17) angstrom, alpha = 116.404(3)degrees, beta = 94.574(4)degrees, gamma = 103.031(4)degrees, V = 541.0(2) angstrom(3), Z = 1, R-gt(F) = 0.0445, wR(ref)(F-2) = 0.1147, T = 296.15 K.

The processing of duckweed has been included in the list of promising pathways for biofuels production. This property is attributed to its simple manual harvesting method and its ability for high protein or starch content, depending on its species and growing environment. The biofuels production from duckweed, is not only a solution to energy and environmental problems, but also a reliable way to realize the utilization of duckweed. This critical review focuses on the bio-oil production from duckweed via pyrolysis and hydrothermal liquefaction processes. First, characteristics and eco-environmental benefits of duckweed are reviewed. Next, the impacts of different parameters on the properties and distribution of bio-oil from pyrolysis and hydrothermal liquefaction are discussed in detail. Subsequently, the effect of hydrogen donor solvents (as reaction media for upgrading) and catalysts on the upgrading of duckweed bio-oil are extensively discussed. This paper ends with the prospects for further development in thermochemical valorization of duckweed. (C) 2021 Elsevier B.V. All rights reserved.

Among the various problems the world is facing, two problems are addressed in this paper. On the one hand, biomass, the fourth largest and most important renewable energy option that can provide different forms of energy, is criticized because it competes, sometimes, with the food chain. On the other hand, the amount of municipal sewage sludge has continued to increase over the years, and its disposal remains a crucial point of discussion between urban planners, wastewater managers, and leaders of environmental protection. To address this problem, researchers are directing their focus toward alternatives to conventional biomass resources, such as organic wastes and residues. Thus, municipal sewage sludge is a likely candidate for energy and high-value added material production. Regarding this issue, one of the main methods proposed by researchers is the pyrolysis process. The aim of this paper is to review the research conducted on sewage sludge conversion through the pyrolysis process. After characterizing municipal sewage sludge, we present a summary of the sewage sludge pyrolysis process. Then, the effects of some of the most influential parameters are examined. The last main part of this work is dedicated to the nitrogen transformation pathway during this process.

Algae biomass has recently attracted the attention of the green energy industry as a raw material for biofuels production. Their high-water content has led to the choice of hydrothermal liquefaction as a suitable way to convert them into bio-oil. From algae species to bio-oil as fuel, many steps are required, including the selection of algae species and process parameters (including catalysts), the liquefaction process, product separation, recovery of crude bio-oil, and subsequent upgrading (if the goal is to use the bio-oil as transportation fuel). This review gives some biochemical, elemental, and inorganic compositions of algae. The reaction mechanism of hydrothermal liquefaction is briefly described, with an emphasis on the influence of process parameters on the yield and quality of the crude bio-oil. The use of organic solvents as reaction media or for recovery of crude bio-oil from product mixtures is discussed. The research work on the catalytic hydrothermal upgrading of algae liquefied crude bio-oil in recent years is reviewed, and some conclusions are put forward. According to recent reports, there is a section devoted to the techno-economic analysis of the hydrothermal liquefaction process. Finally, the challenges that future research and new development strategies may face are proposed.

Hydrothermal liquefaction of Auxenochlorella pyrenoidosa (AuP) and Arthrospira platensis (ArP) at 350 degrees C for 1 h produced algal biocrudes (BCs), BC(AuP) and BC(ArP), with yields of 41.82 and 36.60 wt.Wo, respectively. These two algal BCs were cut into five distillate fractions (DFs) of 25-100 degrees C (DFO), 101-200 degrees C (DF1), 201-300 degrees C (DF2), 301-400 degrees C (DF3), and >= 401 degrees C (DR) using atmospheric distillation under N-2 atmosphere. The total yields of DF1, DF2, and DF3 from either BC(AuP) or BC(ArP) are at least 60 wt.%. All the DFs, from either AuP or ArP, showed different yields and elemental and molecular compositions. Next, the DF1, DF2, and DF3 DFs were each blended with used engine oil (UEO) at a mass ratio of 1:1 and treated at 400 degrees C for 4 h with an additional 0.1 kg(Pt/C)/kg(feed) under 6 MPa H-2. The presence of UEO could dilute the DF, avoid solvent extraction of the product oil, favor desulfurization of the upgraded oil, and be directly recovered as a major part of the product oil. Catalytic hydrotreatment of the DF and UEO blends led to a higher upgraded oil yield (> 79 wt.%) and lower coke (< 12 wt.%) and gas (< 9 wt.%) yields compared with those from the BCs alone under the same process conditions, and higher upgraded oil yields were achieved when using the DFs with high boiling point ranges. The upgraded oil had a lower total acid number and oxygen, nitrogen, and sulfur contents than those of the BC. The sulfur contents of the upgraded oil produced from the DF and UEO blends were much lower than those from the BCs alone, and the lowest sulfur content of 12 ppm (w/v) was achieved. The high abundance of unsaturated hydrocarbons and nitrogen- and oxygen-containing compounds in the BC were replaced by a high abundance of hydrocarbons and benzene derivatives in the upgraded oil. The heating value of the upgraded oil ((similar to)48 MJ/kg) was higher than that of the BC. The main gas-phase products were H-2, CH4, C2H6, and C3H8 Overall, many of the properties of the upgraded oils obtained from the catalytic hydrotreatment of the DF and UEO blends were similar to those of hydrocarbon fuels derived from fossil fuel resources.

The characterization of products produced from hydrothermal liquefaction of algal biomass is helpful to better understand the effect of different kinds of raw materials on the properties of the product fractions. The data presented in this article are related to the research article entitled "Integration of hydrothermal liquefaction and supercritical water gasification for the improvement of energy recovery from algal biomass" (Duan et al., 2018) [1]. In this data article, the compositions of gaseous products produced from hydrothermal liquefaction of eight different algae feedstocks at 350 °C for 60 min were analyzed by gas chromatography. The molecular and elemental compositions of the crude bio-oils produced from hydrothermal liquefaction of eight different algae feedstocks at 350 °C for 60 min were analyzed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry and organic elemental analyzer. The color of aqueous phases before and after they were subjected to supercritical water gasification was recorded by a high-resolution camera. © 2018 The Authors