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1.
Environ Res ; 216(Pt 4): 114742, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36347393

RESUMO

The main focus of the study was to witness the effects of chicken waste-based biodiesel blends along with constant hydrogen injection in a modified diesel engine. Furthermore, the nanoparticle multiwall carbon nanotubes (MWCNT) effects on the engine efficiency were also examined. A series of tests was conducted in the single cylinder, water cooled engine fuelled with diesel, CB100N, CB10N, CB30N, and CB50N. Throughout the entire run, constant hydrogen injection of 5 LPM has been maintained. The parameters such as brake thermal efficiency, brake specific fuel consumption, heat release rate and the emissions of different pollutants were determined for a variety of engine speeds. ASTM standards were applied to measure the viscosity, density and calorific value. From the reported findings, it was clear that the addition of the chicken waste biodiesel could be a sustainable substitute for the existing fossil fuels. Although the emission of the pollutants was dropped significantly, there was a massive drop in the BTE values. To compensate such shortage of power, the biodiesel was dispersed with MWCNT at the concentration of 80 ppm. Compared to the regular biodiesel, MWCNT inclusion increased the BTE by 14%. Further, the consumption of the fuel was also reduced marginally. Considering the pollutants, the catalytic activity of the MWCNT reduced the emissions of CO, NOx, and HC at various engine speeds. Besides, 10% reduction in NOx had been reported at lower engine speeds and was reduced to 8% at higher speed regimes. Compiling all together, increasing the concentration of the biodiesel blends obviously reduced the performance values and however, there was a great advantage in terms of the emission magnitudes irrespective of the engine operating conditions.


Assuntos
Poluentes Ambientais , Nanotubos de Carbono , Animais , Biocombustíveis , Monóxido de Carbono/análise , Galinhas , Gasolina , Hidrogênio , Emissões de Veículos , Gorduras
2.
J Environ Manage ; 302(Pt B): 114046, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34775338

RESUMO

This paper reviews the new progress, challenges and barriers on production of pyrolysis oil from the plastic waste. Among the different processes thermal and catalytic are the potential methods to produce oil. Since the global plastic production increased over years the accumulation of plastic waste increases. Thus, converting the waste plastics into useful energy is very essential to avoid the environmental concerns. Initially the thermal pyrolysis process and its advantage on production of pyrolysis oil were discussed. During the thermal decomposition the waste plastic had been converted into the products such as gas, crude oil and solid residues. Secondly, the catalytic process and its recent trends were discussed. In addition, the factors affecting the catalytic pyrolysis process had been evaluated. Furthermore, the optimized concentration of catalyst subjected to the higher yield of fuel with low hydrocarbon content was found. The pyrolysis oil produced from the catalytic process has higher heating values, lower density and lower viscosity compared to thermal process. In addition, the application of pyrolysis oil on the diesel engines had been discussed. The effects of pyrolysis oil on combustion and emission characteristics were observed. This review summarizes the potential advantages and barriers of both thermal and catalytic process. Further, the optimized solutions and applications of pyrolysis oil are suggested for sustainability of the process. Besides the introduction of the pyrolysis oil were viable without making major modification to the existing engine design.


Assuntos
Plásticos , Pirólise , Catálise , Hidrocarbonetos
3.
Chemosphere ; 350: 141005, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38135127

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are widely present in the atmosphere and primarily originate from the incomplete burning of fossil fuels and biofuels. Exposure to PAHs leads to harmful effects on human health and the environment. Diesel engines are a major source of PAH production in the transportation sector. Various approaches have been employed to reduce PAH emissions from diesel engines, including the use of biodiesel, green gaseous fuels, exhaust gas recirculation, exhaust after-treatment, and genetically modifying biodiesel with nanoparticles. This review focuses on PAH emissions from different generations of fuels and examines the remedial control actions taken to mitigate PAH formation. The study underscores the necessity for effective regulation of emissions from diesel engines, especially in developing countries where the reliance on fossil fuels is significant. Biodiesel has shown promise in reducing PAHs and carcinogenic pollutants, with higher biodiesel concentrations resulting in lower PAH formation. Replacing diesel with biodiesel and optimizing engine operating conditions are feasible methods to reduce PAH levels in the atmosphere. The use of nanoparticles in fuel blends and higher oxygen content in combustion chambers are also considered potential strategies for pollutant reduction. Additionally, the utilization of hydrogen and ammonia as secondary fuels has been explored as promising alternatives to fossil fuels. The study highlights the importance of further research on the presence of residual PAHs in the atmosphere and the implementation of strategies to curtail vehicular emissions.


Assuntos
Poluentes Atmosféricos , Poluentes Ambientais , Hidrocarbonetos Policíclicos Aromáticos , Humanos , Poluentes Atmosféricos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Gasolina , Biocombustíveis/análise , Emissões de Veículos/prevenção & controle , Emissões de Veículos/análise , Hidrocarbonetos/análise , Combustíveis Fósseis
4.
Chemosphere ; 293: 133475, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34974045

RESUMO

The petroleum fuel demand with high price and its exhaustion imposes a pressure to find an alternative. The fossil fuel shortage has been deteriorating over the past few years, because of the rapid increase in population. Many attempts have been made to increase the quality of biofuel with additives. In this paper, two types of nanoparticles such as carbon nanotubes (CNT) and alumina (Al2O3) in chlorella microalgae biofuel were analyzed by experimental method. The added CNT and alumina act as a catalyst that induces complete combustion with retarded emissions. In addition to above, the noise and vibration qualities are also measured. A series of test conducted using single cylinders, four stroke, naturally aspirated compression ignition diesel engine was run by using pure diesel and also different fuel blends 'such as B10CNT50A50 Chlorella (Microalgae Biodiesel 10% + Diesel 90% + CNT 50 ppm), B20CNT50A50 (Microalgae Biodiesel 20% + Diesel 80% + CNT 50 ppm + Al2O3 50 ppm) and B30CNT50A50 (Microalgae Biodiesel 30% + Diesel 70% + CNT 50 ppm + Al2O3 50 ppm). At a constant load condition, all experimental tests were conducted at four different speeds such as 1500 rpm, 2000 rpm, 2500 rpm and 3000 rpm. The reference fuel of diesel B0 results was compared with blended fuel. From the results, it has been found that the nano additives of CNT and alumina reduced the greenhouse gas emissions of CO compared to plain diesel. Only considering the blended fuel, as the percentage of biofuel increases, the emission of nitric oxide and carbon dioxide is decreased with significant reduction in the amount of noise and vibration and also the combustion and performance qualities were also improved. The highest benefit in terms of all factors was achieved in the fuel blend of B30A50CNT50 amongst the other blends.


Assuntos
Chlorella vulgaris , Microalgas , Nanotubos de Carbono , Acústica , Biocombustíveis , Monóxido de Carbono/análise , Poluição Ambiental , Gasolina , Emissões de Veículos , Vibração
5.
Sci Total Environ ; 802: 149750, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34454158

RESUMO

The continuous growing demand for fossil fuel puts an enormous pressure on finding a better replacement. This research paper explores the detailed information on the improved production, emission and performance characteristics of the distinct bio-oil derived from the micro algae of Schizochytrium. The algae were grown in the artificial seawater with enough nitrogen supply at the required standard conditions. The lipid growth and production of the bio-oil were monitored closely and measured. Different fuel blends were used at different concentrations as B0 (100% Diesel), B10 (10% schizochytrium biofuel +90% diesel), B20 (20% schizochytrium biofuel +80% diesel) and B30 (30% schizochytrium biofuel +70% diesel). A small single cylinder, four stroke diesel engine was used to conduct the tests. All tests were conducted at different speed conditions of 1200 rpm to 2100 rpm in six intervals. The performance qualities of bio-oil such as CO, NOX, and smoke and CO2 emission along with the performance qualities of brake thermal efficiency and brake specific fuel consumption. Form the results, the Schizochytrium microalgae bio-oil as the bio fuel for diesel engines in the moderate level showed the improved performance by increasing the BTE and reducing the harmful gas emissions except NOX. However, the emission level of NOX was slightly higher than the diesel emitted value. The difference between them was negligible.


Assuntos
Biocombustíveis , Gasolina , Monóxido de Carbono/análise , Transferência de Energia , Óxidos de Nitrogênio/análise , Emissões de Veículos
6.
Sci Total Environ ; 796: 149049, 2021 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-34328896

RESUMO

This work outlines major critical physico-chemical parameters that play a key role in increasing the fixation of CO2 from coal-fired flue gas CO2 into green microalgae biomass. Nitrogen concentration, gas flow rate, initial medium pH, and incident light intensity were determined to be the most important process variables with significant impact on CO2 fixation. Therefore, NaNO3 (500-3000 mg L-1), pH (6.8-8.0), light (50-200 mol m-2 s-1) and aeration (0.1-1.0 vvm) were varied to assess the biological assimilation potential of CO2 from the flue gas. The parameters that resulted in maximal CO2 fixation from raw flue gas, resulting in a maximum biomass density of 3.1 g L-1, were NaNO3 = 1500 mg L-1, pH =7.2-7.5, incident light intensity = 133.33 mol m-2 s-1, and 0.5-0.75 vvm aeration without any cost-incurring flue gas pre-treatment step. The inductively coupled plasma-mass spectrometer (ICP-MS) was used to investigate heavy metals uptake from raw flue gas, and it was discovered that no net intake of trace metals had a significant influence on biomass production. The research lays the path for efficient large-scale microalgal cultivations for industrial uses, as well as bolstering the circular economy concept.


Assuntos
Dióxido de Carbono , Microalgas , Biomassa , Sequestro de Carbono , Carvão Mineral
7.
Sci Total Environ ; 771: 144700, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33736139

RESUMO

The present study has tested the biodiesel potential of two hyper lipid producing strains Chlorella sp. and Scenedesmus sp. in terms of biomass yield, quantity and quality of lipid and fatty acid composition. Biomass yield of Chlorella sp. and Scenedesmus sp. was 1.26 and 1.33 g/L, respectively on day 18 and 20. The lipid content and lipid productivity of Chlorella sp. and Scenedesmus sp. was estimated to be 21.3, 26.5% and 12.33, 14.74 mg/L/d, respectively. Notably, relative abundance of lipid types in both the strains revealed >60% neutral lipids followed by glycolipids and phospholipids in minimal level. Central composite design based optimization revealed 69 and 65.4% FAME yield from Chlorella sp. and Scenedesmus sp. at 3% sulphuric acid and 65 °C reaction temperature. Eventually, higher levels of saturated fatty acids (~45%) and monounsaturated fatty acids (~34%) and make Scenedesmus sp. a promising parent material for workable biodiesel production.


Assuntos
Chlorella , Microalgas , Scenedesmus , Biocombustíveis , Biomassa , Ésteres , Ácidos Graxos , Lipídeos
8.
Bioresour Technol ; 325: 124654, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33461123

RESUMO

Considering the glitches in making commercially realistic fuel, this research article has demonstrated the lipid accumulation in four fast growing, filamentous cyanobacterial strains. On day 26, the lipid content estimated was 6.7, 8.2, 10.2, and 9.4% from Phormidium sp. FW01, Phormidium sp. FW02, Oscillatoria sp. FW01, and Oscillatoria sp. FW02, respectively. Of the photosynthetically active radiation (PAR) tested, 2000 lx was found to higher biomass and lipid at about 1.83 g/L and 12.5%, respectively for Oscillatoria sp. FW01. Of <5 °C, 15 °C, 25 °C, 37-40 °C tested, 11.2% lipid was extracted from Oscillatoria sp. FW01 grown at 37-40 °C and pH did not make any changes in biomass and lipid content. The optimized abiotic conditions showed higher polar lipids about 75% in all the tested cyanobacteria and further, Oscillatoria sp. FW01 yielded 57% fatty acid methyl ester, which contains desirable fatty acids C 16:0, C 16:1, C18:1, C18:3 for high quality biodiesel.


Assuntos
Cianobactérias , Microalgas , Biocombustíveis , Biomassa , Ácidos Graxos , Lipídeos
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