• Energy Research

Abstract Energy demand is increasing continuously due to the progress of industrialization, the vehicular population of the world, and modernization in lifestyle. In the present study, Chlorella minutissima microalgae were cultured in a 1500 L raceway open pond using commercial fertilizer under semi-continuous mode. About 19.98 wt % lipid was extracted by the soxhlet extraction method from this microalgae biomass. To optimize the input reaction parameters (temperature, lipid to methanol ratio, microwave power, and reaction time) for improving transesterification yield, Response Surface Methodology (RSM) was employed. The output responses of the experiments were biodiesel yield along with density, kinematic viscosity, calorific value, cold flow properties, and oxidation stability. To validate the model, confirmation trials were carried out. All the fuel properties were found to be satisfying ASTM D6751 and EN 14214 standard specifications except for oxidation stability at 3.0 h. The oxidation stability was further improved by using appropriate antioxidants and improved up to 10.5 h with the addition of 1000 ppm propyl gallate.

In this study, the performance of a high-temperature water gas shift reaction (WGSR) using a Fe-Cr catalyst along with a Pd alloy membrane was simulated by computational fluid dynamics (CFD). The influences of using Pd membranes, catalytic layer thickness ratio (R/R0), Reynolds number, and steam-to-CO ratio (S/C) on the reaction were investigated by comparing CO conversion and hydrogen recovery (HR). In the CFD simulation, one-tube and four-tube systems were simulated at 500 °C. This study also compared the performance between tandem and optimized configurations. The results show that the CO conversion can be improved up to 22.9% when the WGSR reactor system uses a Pd membrane compared to the system without a Pd membrane. The system has the best hydrogen recovery performance at S/C = 4 and R/R0 larger than 1.5. At Re=5, the optimized configuration for CO conversion has better performance when R/R0 is larger than 1.75. Compared to the tandem configuration, the optimized configuration also shows better performance for HR at every R/R0. The results indicate that a Pd membrane and optimized configuration can significantly improve CO conversion and that R/R0 and S/C optimization is very important for effective reactor performance.

Biodiesel is an emerging alternative fuel that is generally made from edible and non-edible oilseed crops. Jatropha curcus has a high potential for producing biodiesel, which yields 25–35% oil along with 75–65% solid byproduct, generally called a de-oiled cake. The present manuscript deals with the co-digestion of Jatropha de-oiled cake along with cattle dung (1:1 ratio) for biogas production in a floating-type biogas digester. The experimental study was carried out in a modified KVIC biogas plant of 6 cubic meter capacity for 60 days’ retention time under psychrophilic and mesophilic temperature conditions. During all the experiments, the total solid content of the slurry was maintained fixed at 10–12% by mixing 10 kg Jatropha de-oiled cake and 10 kg cattle dung with 80 kg water. The experimental results showed that the average specific biogas production of Jatropha de-oiled cake and cattle dung slurry was observed to be 0.216 m3/kg TS, 0.252 m3/kg VS and 0.287 m3/kg TS, 0.335 m3/kg VS, respectively, under the aforementioned conditions. Moreover, the biogas methane concentration was observed to be 62.33% to 69.16% under mesophilic temperature conditions compared to the psychrophilic temperature conditions, 65.21% to 69.15%, respectively. Furthermore, the average total volatile solids mass removal efficiency of feeding material in the abovementioned process was 7% higher under mesophilic temperature conditions than psychrophilic temperature conditions. Additionally, the results indicated that a total 588.8 kg of input volatile solids produced a total of 7306.56 MJ/m3 and 5177.88 MJ/m3 energy in 60 days under psychrophilic and mesophilic temperature conditions. On the basis of the results, it is concluded that Jatropha de-oiled cake may be a superior solution for improving biogas quality and composition as well as a value-added product, i.e., organic manure.

Abstract The present study is focused on conversion of non-edible Jatropha seeds biomass to biofuels i.e., liquid, solid and gaseous fuels via solar thermochemical pyrolysis process. All the three products namely; (i) bio-oil (liquid) (ii) biochar (solid) and (iii) pyrolytic gas were characterized by means of TG (Thermo-gravimetric), FTIR (Fourier transform infrared), GC–MS (Gas chromatography mass spectroscopy), proximate and ultimate analysis; and assessed their feasibility as fuel candidates. It is explored that 20% maximum bio-oil yield was obtained with the average reactor temperature of 250–320 °C. The pyrolytic zone for the biomass was identified in the range of 203–508 °C. The ultimate analysis of the bio-oil revealed that the oil is rich in carbon (58.3%) and hydrogen (8.7%) with an average chemical composition of CH1.79N0.05O0.40. Relatively lower oxygen content in the bio-oil favors for high heating value. Higher H/C ratio (1.79) and lower O/C ratio (0.4) of the bio-oil indicates its suitability as petroleum fuel for engine applications. The carbon compounds present in the bio-oil are from C7 to C28 which may represent the mixture of diesel and gasoline fuels. Finally, it is emerged from the study that all the three products are exibiting various favorable conditions to be employed as fuel candidates for different applications such as engines and boilers.

Mathematical modeling is an integral part of the design to necessitate lower production costs and optimized performances. Biomass gasification is an area wherein extensive research is ongoing to ta...

Microwave enhanced fast and efficient alcoholysis (methanolysis and ethanolysis) of non-edible oils (algal, jatropha and pongamia) is achieved using chemically activated waste egg shell derived CaO (i.e. CaO(cesp)) as heterogeneous catalyst. CaO(cesp) was extracted from waste chicken egg shell and further activated chemically by supporting transition metal oxide. The maximum conversion was achieved using 3wt% catalysts under 700W microwave irradiation and 10:1 alcohol/oil ratio in 6min. Alcoholysis using ZnO activated CaO(cesp) catalyst has shown higher reaction yields in comparison to other modified catalysts. Methanolysis has shown better biodiesel conversion in comparison to ethanolysis. The catalyst has shown longer lifetime and sustained activity after being used for four cycles. Due to more saturated fatty acid content; algal biodiesel has shown improved fuel properties in comparison to other biodiesels.

Uttarakhand has the maximum potential of pine of about 20 lakh tonnes/year including reserved forests and van panchayat which makes pine needle an abundant resource. The analysis of the pine needles reveals it a potential biomass feedstock for gasification to produce electricity. This manuscript deals with the combustion study of Pine needles (Pinusroxburghii) biomass using a thermogravimetric analyzer to investigate the thermal degradation behavior and kinetic parameters. The pine needles were heated in the presence of air at four different heating rates 5, 10, 25 and 50 °C/min, and the degradation phenomenon was studied. From the proximate and ultimate analysis of pine needles, it was observed that the biomass could be a potential feedstock for gasification. The TG-DTG curves revealed that the main decomposition was between 190 and 450 °C with the release of 80–84% volatiles. It was observed that as the heating rate increases, the maximum decomposition temperature also increases and the peak shifts to the right. The obtained thermal data were used to calculate the kinetic parameters using Kissinger–Akharia–Sunose, Ozawa-Flynn-Wall, Friedman and Kissinger. The average values obtained from the above methods are 190.74, 190.75, 199.48 and 172 kJ/mol and 2.749 × 1022, 5.13 × 1022, 4.21 × 1021 and 4.14 × 106/min, respectively. The model fitting method and Coats–Redfern method were used to determine the kinetic triplet (A, E and n). The above model-free methods and model fitting methods predicts the progress of gasification at different positions along the reactor. Considering proximate analysis and heating value, pine needles could be considered as a potential feedstock for energy production through gasification process. The estimated results help as a source to understand the thermal degradation of biomass during the gasification process and be used to design the systems.

Rapid climate change and forecasted damage from fossil fuel combustion, forced researchers to investigate renewable and clean energy sources for the sustainable development of societies throughout the world. Biomass-based energy is one of the most important renewable energy sources for meeting daily energy needs, which are gaining in popularity daily. Gasification-based bioenergy production is an effective way to replace fossil fuels and reduce CO2 emissions. Even though biomass gasification has been studied extensively, there is still much opportunity for improvement in terms of high-quality syngas generation (high H2/CO ratio) and reduced tar formation. Furthermore, the presence of tar has a considerable impact on syngas quality. Downdraft gasifiers have recently shown a significant potential for producing high-quality syngas with lower tar concentrations. This article presents a comprehensive review on the advancement in biomass downdraft gasification technologies for high-quality synthesis gas. In addition, factors affecting syngas production and composition e.g., equivalency ratio, temperature, particle size, and gasification medium on synthesis gas generation are also comprehensively studied. The up-gradation and various applications of synthesis gas are also discussed in brief in this review article.