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•Biodiesel production from commercially Jojoba seed is explored.•The effect of variables on oil extraction was explored via CCD-RSM methodology.•44.76 wt.% saponifiable oil can be ...extracted from Jojoba seed.•The highest biodiesel production yield is attained at 50 °C with a yield of 66.5%.
Biodiesel production is explored in the current study through the ex-situ extraction and trans-esterification approach from commercially available Jojoba seed. This biomass is regarded as a beneficial feedstock for biodiesel production as it contains non-edible oil. Also, this feedstock can be cultivated and grown in wastewater and in variable climate conditions. According to the characteristic analysis Jojoba oil is composed of 6.9% saturated fatty acids (4.6% C16:0, 1.3% C18:0 and 0.2% C20:0), 68.7% monounsaturated fatty acids (48% C20:1, 20.2% C18:1 and 0.5% C16:1) and 24.4% polyunsaturated fatty acids (14.8% C18:2, 9.2% C20:2 and 0.4% C18:3). The acid value of crude Jojoba oil is 0.05 mg KOH/ g sample, which feasible the alkaline catalyzed trans-esterification. The effect of variables on oil extraction was explored preliminary through the time-efficient and low-cost central composite design response surface methodology (CCD-RSM). According to the results, 67.51 wt.% saponifiable oil can be extracted from Jojoba seed at 64.5 °C, reaction duration of 187.7 min, rotation rate of 393.2 rpm, and solvent to biomass ratio of 14.6 cc:1 g. The maximum yield of biodiesel production is also obtained at 50 °C, methanol to oil molar ratio (MeOH: Oil) of 5.5:1, reaction time of 2.25 h, and 0.475 wt.% (KOH weight/ oil weight) KOH loading.
Propane dehydrogenation on a commercial Pt‐Sn/Al2O3 catalyst in a Pd‐Ag membrane reactor is considered. A mathematical model is developed to evaluate the performance of the catalytic membrane reactor ...for the process of propane dehydrogenation. Design and operating conditions are systematically evaluated for key performance metrics such as propane conversion, propylene selectivity, hydrogen selectivity, and hydrogen recovery under different operating conditions. The results confirm that the high performance of the membrane reactor is related to the continuous removal of hydrogen from the reaction zone to shift the reaction equilibrium towards the formation of more propylene and hydrogen.
The influence of various design and operating parameters on hydrogen and propylene production is evaluated. By considering the technical challenges and energy source limitations, the developed model based on relevant industrial condition in this research could support process researchers to establish new efficient technologies for industrial coproduction of hydrogen and propylene.
Waste conversion is a major challenge for energy production in the future circular economy. Waste management aims at producing more energy and recyclable materials, in order to reduce landfill ...disposal and pollution. Here, membrane technologies are developing for waste conversion to dihydrogen. Here we review techniques of waste conversion such as incineration, pyrolysis, gasification and anaerobic digestion, with focus on waste gasification to produce syngas and then pure hydrogen using a membrane reactor.
In the present study, hydrogen-rich syngas production via integrated configuration of pyrolysis and air gasification processes of different algal biomass is investigated at relevant industrial ...condition. A comprehensive steady state equilibrium simulation model is developed using Aspen Plus software, to investigate and evaluate the performance of pyrolysis and air gasification processes of different algal biomass (Algal waste, Chlorella vulgaris, Rhizoclonium sp and Spirogyra). The model can be used as a predictive tool for optimization of the gasifier performance. The developed process consists of three general stages including biomass drying, pyrolysis and gasification. The model validation using reported experimental results for pyrolysis of algal biomass indicated that the predicted results are in good agreement with experimental data. The effect of various operational parameters, such as gasifier temperature, gasifier pressure and air flow rate on the gas product composition and H2/CO was investigated by sensitivity analysis of parameters. The achieved optimal operating condition to maximize the hydrogen and carbon monoxide production as the desirable products were as follows: gasifier temperature of 600 °C, gasifier pressure of 1 atm and air flow rate of 0.01 m3/h.
•Syngas production via integrated configuration of pyrolysis and gasification processes is studied.•Air gasification of different algal biomass is investigated at relevant industrial condition.•The new configuration is simulated using Aspen Plus software.•The sensitivity analysis of operating condition on the process performance is considered.•The optimum operating condition to maximize syngas production is determined.
The steam reforming of methanol was investigated in a catalytic Pd–Ag membrane reactor at different operating conditions on a commercial Cu/ZnO/Al2O3 catalyst. A comprehensive two-dimensional ...non-isothermal stationary mathematical model has been developed. The present model takes into account the main chemical reactions, heat and mass transfer phenomena in the membrane reactor with hydrogen permeation across the PdAg membrane in radial direction. Model validation revealed that the predicted results satisfy the experimental data reasonably well under the different operating conditions. Also the impact of different operating parameters including temperature, pressure, sweep ratio and steam ratio on the performance of reactor has been examined in terms of methanol conversion and hydrogen recovery. The modeling results have indicated the high performance of the membrane reactor which is related to continuous removal of hydrogen from retentate side through the membrane to shift the reaction equilibrium towards formation of hydrogen. The obtained results have confirmed that increasing the temperature improves the kinetic properties of the catalyst and increase in the membrane's H2 permeance, which results in higher methanol conversion and hydrogen production. Also it is inferred that the hydrogen recovery is favored at higher temperature, pressure, sweep ratio and steam ratio. The model prediction revealed that at 573 K, 2 bar and sweep ratio of 1, the maximum hydrogen recovery improves from 64% to 100% with increasing the steam ratio from 1 to 4.
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•The steam reforming of methanol process was investigated in a catalytic membrane reactor.•A comprehensive 2-dimensional non-isothermal stationary model has been developed.•The impacts of operating parameters on the performance of reactor have been examined.•This research provides a starting point for optimum conversion of methanol to hydrogen.
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•A two step method was developed to produce high purity Ni from spent DRI catalyst.•Complete Ni extraction with negligible Al dissolution could be achieved by HCl leaching.•Quadratic ...models were generated to predict Ni recovery and undesired Al dissolution.•Ni cementation by Al powder was investigated thoroughly using optimal leached liquor.•The optimal cementation condition for higher Ni efficiency and purity were introduced.
In the present study, a novel two-step method was developed to synthesize high purity magnetic nickel from spent direct reduction of iron (DRI) catalyst. Initially, nickel was leached from spent DRI catalyst by hydrochloric acid and the effect of important parameters including temperature (25–85 °C), leaching time (30–210 min), acid concentration (1–5 M) and average catalyst particle size (111–325 μm) were studied using design of experiments (DOE) approach. 100% Ni extraction with negligible Al dissolution (<0.5%) could be achieved at a temperature of 46 °C, leaching time of 172 min, the acid concentration of 4 M and particle size of 111 μm. Next, the nickel cementation by aluminium powder was investigated thoroughly by considering solution initial pH, aluminium particle size and its addition method, pH adjustment method and temperature as important variables. The structural properties of cemented nickel were characterized by FESEM, XRD and EDX analysis. It was observed that through treating of the optimal leached liquor with 2 M sodium hydroxide, more than 96% of Ni could be recovered by gradual addition of excess Al powder to the solution with initial pH of 0.2. The purity of cemented Ni would be 98.5% if the cementation process was performed at 80 °C.
The purge gas emission of ammonia synthesis plant which contains hazardous components is one of the major sources of environmental pollution. Using integrated configuration of catalytic ...hydrogen-permselective membrane reactor and solid oxide fuel cell (SOFC) system is a new approach which has a great impact to reduce the pollutant emission. By application of this method, not only emission of ammonia and methane in the atmosphere is prevented, hydrogen is produced through the methane steam reforming and ammonia decomposition reactions that take place simultaneously in a catalytic membrane reactor. The pure generated hydrogen by recovery of the purge gas in the Pd–Ag membrane reactor is used as a feed of SOFC. Since water is the only byproduct of the electrochemical reaction in the SOFC, it is recycled to the reactor for providing the required water of the reforming reaction. Performance investigation of the reactor represents that the rate of hydrogen permeation increases with enhancing the reactor temperature and pressure. Also modeling results indicate that the SOFC performance improves with increasing the temperature and fuel utilization ratio. The generated power by recovery of the purging gas stream of ammonia synthesis plant in the Razi petrochemical complex is about 8 MW.
•A new configuration is proposed for purge gas recovery of ammonia synthesis plant.•A membrane reactor is used to generate pure hydrogen as feed of SOFC.•An electrochemical model for SOFC is developed.•Parametric analysis of the membrane reactor and SOFC performance is done.
In the present study, application of catalytic membrane reactor as a novel approach for the flare gas recovery is proposed. A comprehensive two-dimensional non-isothermal model has been constructed ...to evaluate the performance of flare gas recovery process in the membrane reactor. The model is developed by taking into accounts the main chemical kinetics, heat and mass transfer phenomena and hydrogen permeation in the radial direction across a Pd–Ag membrane. The model predictions are validated based on different experimental results reported in literature. The impact of reactor operating conditions on the recovery process such as temperature and pressure, feed molar ratio and sweep gas ratio are investigated and discussed. The modeling results confirm that the flare gas conversion and hydrogen recovery improves with increasing the operating temperature, pressure and sweep ratio as a consequence of increasing the driving force for H2 permeation through membrane. The environmental consideration revealed that by application of catalytic membrane reactor for the flare gas recovery of Asalouyeh gas processing plant (Iran), not only the equivalent mass of greenhouse gases emission reduces from 2179 kg/s to 36 kg/s, but also, 12.7 kg/s pure hydrogen will be produced by flare gas recovery at 750 K, 5 bar, sweep ratio of 5 and feed molar ratio of 4.
•Recovery of hydrogen from flare gas has been evaluated.•A catalytic Pd–Ag membrane reactor has been applied for conversion of flare gas.•A comprehensive 2-D non-isothermal stationary mathematical model has been developed.•The impacts of operating parameters on the performance of membrane reactor have been examined.
Chlorella Vulgaris microalgal as a renewable and economically feasible oil feedstock is used in this study for producing biodiesel through electrochemical and thermal processes. The effect of ...operating parameters on non-catalytic and catalytic biodiesel production from the derived-oil is investigated and compared in a wide range of condition. According to the revealed data, during non-catalytic processes, electrochemical process proposed higher biodiesel production yield in comparison to thermal process with relative biodiesel production yield of 25% and 18%, respectively. According to the experimental results, although biodiesel production is restricted in presence of water in thermal process, electrochemical method enables biodiesel production in presence of water. Addition of H2SO4 in the range of 1–15 wt% through electrochemical process at the obtained optimum condition results in gradual increase in the biodiesel production yield to 95%. The optimum operating condition in electrochemical process are as follows: methanol to oil molar ratio of 20:1, tetrahydrofuran (THF) to methanol molar ratio of 0.25:1, reaction time of 2 h, voltage of 20 V/cm, water content of 2 wt% and H2SO4 loading of 15 wt%.
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•Biodiesel production via electrochemical process has been investigated.•Biodiesel production from Chlorella Vulgaris microalgal-derived oil has been studied.•The effect of main operating parameters have been evaluated.•Non-catalytic and catalytic conversions are studied at mild operating condition.
