1,721,014 research outputs found
Technical feasibility of biodiesel production from virgin oil and waste cooking oil: Comparison between traditional and innovative process based on hydrodynamic cavitation
No full textBiodiesel production calls for innovative solutions to turn into a competitive process with a reduced environmental impact. One of the process bottlenecks stands in the immiscibility of oil and alcohol as raw materials, so mixing process largely impacts the overall process cost. This process step, if carried out by using hydrodynamic cavitation, has the possibility to become a benchmark for large scale applications. In this paper a process analysis of biodiesel production scheme is developed starting from two different feedstocks, virgin oil and waste cooking oil. At the first the traditional process scheme has been simulated, in a second simulation, the reactor for the biodiesel production is interchanged with a hydrodynamic cavitation reactor. In the paper, the comparison between the traditional and innovative process by using life cycle costing approach has been presented, thus providing indications for industrial technological implementation coming from a professional tool for process analysis. It is worth noting that the introduction of hydrodynamic cavitation reduces of about 40% the energy consumption with respect to the traditional process. As regards the total treatment costs, when using virgin oil as feedstock, they were in the range 820–830 €/t (innovative and traditional process, respectively); while starting from waste cooking oil the costs decreased of about 60%, down to 290–300 €/t (innovative and traditional process, respectively)
Adsorption of CO2 by synthetic zeolites
No full textThe paper reports on a possible way to recycle fluid catalytic cracking catalysts (FCCCs), widely used in oil refining operations. This research proposes a novel approach that leads to a near zero-waste process. The spent FCCC was leached by 1.5 mol/L of HNO3, HCl and H2SO4 solutions at 80°C, for 3 h with a solid to liquid ratio of 20 %wt/vol. The leaching yields for cerium and lanthanum were in the range 69-82 %. The solid residues from the leaching stage were used as base material for the synthesis of the zeolites by means of a combined thermal-hydrothermal treatment. The characterization of the zeolites demonstrated that the Na-A phase was predominant over the Na-X phase. The zeolites were tested as sorbent material for CO2 separation from CH4, in order to simulate the upgrading of biogas to biomethane. The maximum adsorption rate of CO2 was 0.778 mol CO2/kg of zeolite at 3 bar, with a resulting CH4 recovery of 62 % and purity of 97 %vol. The zeolites synthesized from spent FCCC represent a feasible solution to recover such industrial waste
Pilot-scale experiences with aerobic treatment and chemical processes of industrial wastewaters from electronics and semiconductor industry
Full text linkTMAH is quaternary ammonium salt, consists of a methylated nitrogen molecule, and is widely used in the electronics industry as a developer and silicon etching agent. This substance is toxic and fatal if ingested. It can also cause skin burns, eye damage, and organ damage. Moreover, TMAH exhibits long-lasting toxicity to aquatic systems. Despite this known toxicity, the authorities currently do not provide emission limits (i.e., discharge concentrations) for wastewater by EU regulation. The current scenario necessitates the study of the processes for industrial wastewater containing TMAH. This work aims to present a successful example of the treatment process for the degradation of TMAH waste solutions of the E&S industry. Research was conducted at the pilot scale, and the process feasibility (both technical and economic) and its environmental sustainability are demonstrated. This process, which treats three exhausted solutions with a high concentration of toxic substances, is considered to be innovative
Water reuse in the textile industry with integrated treatments: membranes and advanced oxidation processes
No full textNowadays, traditional methods for dye removal from industrial effluents have been integrated with chemical oxidation processes, mainly advanced oxidation processes (AOPs) which are able to degrade complex organic substances. In this paper, the integration of membrane process and hydro-dynamic cavitation for the treatment of a dyeing wastewater is presented. The degradation efficiency of two dyes (methyl orange and methylene blue) obtained in previous experimental activity and here resumed are used as an input to simulate an integrated treatment cycle in which dyeing waste-water is pre-treated, filtrated through a membrane operation, subjected to an AOP with hydrody-namic cavitation in a hybrid configuration. The integration among physical treatment (membrane) and chemical/physical treatment (hydrodynamic cavitation coupled with Fenton treatment) allows to obtain a depurated stream (permeate) that can be reused as process water and a concentrated stream (retentate) that after the treatment can be safely discharged into superficial body
Techno-economic analysis of olive wastewater treatment with a closed water approach by integrated membrane processes and advanced oxidation processes
Full text linkIn this paper, a reliable treatment process for olive mill wastewaters (OMWW) is proposed. In order to develop a more sustainable process with polyphenols recovery and water reuse, two treatment schemes have been simulated by using a process simulator (SuperPro Designer® ), depending on wastewater characteristics; the first applied for ‘biological’ effluents by using membrane technology (microfiltration MF, ultrafiltration UF, nanofiltration NF and reverse osmosis RO), the second for wastewaters containing pesticides, in which RO is replaced with an advanced oxidation process for pesticide degradation. The results of the process analysis showed that the final permeate is a treated water suitable for both disposal in aquatic receptors and for civil or agriculture reuse. Moreover, the results of a techno-economic analysis of the proposed processes is presented, carried out by means of a life cycle cost analysis, considering the mass and energy balances obtained from process analysis. The analysis showed that the first scenario is more economically feasible. In detail, the treatment cost (€/m3 of OMWW) was 253 and 292 €/m3 for the first and second case study, respectively. However, the second process scheme result is inappropriate if the wastewater to be treated does not come from biological olive processing
Leaching of yttrium from cathode ray tube fluorescent powder: Kinetic study and empirical models
No full textComparison of performances of hydrodynamic cavitation in combined treatments based on hybrid induced advanced Fenton process for degradation of azo-dyes
No full textIn the present work, the degradation of azo-dyes in aqueous solutions by using hydrodynamic cavitation is performed. Methyl orange was chosen as colorant model pollutant. During the experimental tests, the effect of various operating parameters on the decolourization efficiency was investigated. In the first series of experiments, the hydrodynamic cavitation was optimized in terms of operating inlet pressure and cavitation number to get the maximum decolorization yields of the dye, at the constant temperature of 20 degrees C and with an initial methyl orange concentration equal to 5 ppm. It was observed that there was an optimum inlet pressure value (4 bar) to get the best decolourization efficiency (about 32%). For the optimal configuration, in correspondence of 4 bar, a first order kinetic equal to 0.0054 min(-1) and a value of electrical energy per order E-EO of 3793.81 kW h m(-3) were calculated. Subsequently, the combined effect of hydrodynamic cavitation and hydrogen peroxide on dye degradation has been studied. The efficiency of the HC-H2O2 system, under optimal conditions, was more than 50% in terms of dye decolourization. Finally, a series of experiments have been performed by combining hydrodynamic cavitation with the addition of hydrogen peroxide and metal ions (iron and nickel) in solution. The dye degradation became greater than 90%; this increase was explained by supposing that an induced advanced Fenton process has been generate thus improving the performance of the entire cavitation system
Study of the effect of operative conditions on the decolourization of azo dye solutions by using hydrodynamic cavitation at the lab scale
No full textIn the present study, the potentiality of hydrodynamic cavitation (HC) for the degradation of methyl orange from synthetic aqueous solutions is presented. Hydrodynamic cavitation was set up at laboratory scale using a Venturi tube. Solutions of methyl orange (MO) were subjected to cavitation in order to investigate the efficiency and the potential of this technique for azo dye degradation. Moreover, a HC/H2O2/TiO2 hybrid system was tested with the aim to verify its potential positive impact on the decolourization process and define the best conditions, among those investigated, to remove azo dye from synthetic solutions. The results obtained in this study showed that the maximum efficiency was close to 30% using a Venturi tube at an operating pressure of 400 kPa. The presence of additives, such as titanium dioxide and hydrogen peroxide, increased the performance of the degradation process to slightly above 70%
Methyl orange decolourization through hydrodynamic cavitation in high salinity solutions
No full textThis paper presents the experimental results obtained on the decolourization of methyl orange (MO) in saline solutions, carried out through hydrodynamic cavitation (HC), used as a stand-alone technique, and in a hybrid configuration coupling with hydrogen peroxide. Experiments were carried out by adding NaCl in a solution in the range of 1.5 to 5 g/L to study the effect of salt on dye degradation by simulating the composition of a real tannery liquid waste. The results showed that the maximum efficiency was about 30% using a Venturi tube at an operating pressure of 0.55 MPa. The presence of hydrogen peroxide allowed the degradation process to be slightly below 70%; the presence of sodium chloride (5.0 mg/L) increased the decolourization efficiency up to about 70% as well, while the combined presence of NaCl and H2O2 had a negative outcome. The experiments on synthetic waste allowed to gain a MO degradation slightly below 90%. Process analysis was carried out to evaluate the possible integration of the HC within a real wastewater treatment plant by comparing the traditional treatment train with a new plant configuration, in which HC takes the place of a conventional coagulation tank
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