6 resultados para Oil-R134a mixture
em Aston University Research Archive
Resumo:
This research provides a novel approach for the determination of water content and higher heating value of pyrolysis oil. Pyrolysis oil from Napier grass was used in this study. Water content was determined with pH adjustment using a Karl Fischer titration unit. An equation for actual water in the oil was developed and used, and the results were compared with the traditional Karl Fischer method. The oil was found to have between 42 and 64% moisture under the same pyrolysis condition depending on the properties of the Napier grass prior to the pyrolysis. The higher heating value of the pyrolysis oil was determined using an oil-diesel mixture, and 20 to 25 wt% of the oil in the mixture gave optimum and stable results. A new model was developed for evaluation of higher heating value of dry pyrolysis oil. The dry oil has higher heating values in the range between 19 and 26 MJ/kg. The developed protocols and equations may serve as a reliable alternative means for establishing the actual water content and the higher heating value of pyrolysis oil.
Resumo:
Use of agricultural residues, like wheat or rice straw for energy generation, is the most effective measure in terms of costs and availability. The present paper focuses the need of such measure, its impact on the environment as practiced today (open burning). The application of intermediate pyrolysis technology for straw conversion in India is discussed herein. A 20 kg/h Pyroformer has been coupled to a direct quenching system without filtration. The process temperature was around 360 ?C and the yields for the product fractions, char pyrolysis oil, and non-condensable gas fractions were, 32%, 35%, and 33% respectively. The pyrolysis oil was condensed in a quenching unit using bio-diesel or diesel. The blend produced was 30 % pyrolysis liquid and 70 % bio-diesel. The engine has been tested with the pyro-oil/biooil mixture over a long term (75 hours). An overall economic analysis of the process has been carried out.
Resumo:
Fast pyrolysis liquid or bio-oil has been used in engines with limited success. It requires a pilot fuel and/or an additive for successful combustion and there are problems with materials and liquid properties. It is immiscible with all conventional hydrocarbon fuels. Biodiesel, a product of esterification of vegetable oil with an alcohol, is widely used as a renewable liquid fuel as an additive to diesel at up to 20%. There are however limits to its use in conventional engines due to poor low temperature performance and variability in quality from a variety of vegetable oil qualities and variety of esterification processes. Within the European Project Bioliquids-CHP - a joint project between the European Commission and Russia - a study was undertaken to develop small scale CHP units based on engines and microturbines fuelled with bioliquids from fast pyrolysis and methyl esters of vegetable oil. Blends of bio-oil and biodiesel were evaluated and tested to overcome some of the disadvantages of using either fuel by itself. An alcohol was used as the co-solvent in the form of ethanol, 1-butanol or 2-propanol. Visual inspection of the blend homogeneity after 48 h was used as an indicator of the product stability and the results were plotted in a three phase chart for each alcohol used. An accelerated stability test was performed on selected samples in order to predict its long term stability. We concluded that the type and quantity of alcohol is critical for the blend formation and stability. Using 1-butanol gave the widest selection of stable blends, followed by blends with 2-propanol and finally ethanol, thus 1-butanol blends accepted the largest proportion of bio-oil in the mixture. © 2013 Elsevier Ltd. All rights reserved.
Resumo:
Pyrolysis is one of several thermochemical technologies that convert solid biomass into more useful and valuable bio-fuels. Pyrolysis is thermal degradation in the complete or partial absence of oxygen. Under carefully controlled conditions, solid biomass can be converted to a liquid known as bie-oil in 75% yield on dry feed. Bio-oil can be used as a fuel but has the drawback of having a high level of oxygen due to the presence of a complex mixture of molecular fragments of cellulose, hemicellulose and lignin polymers. Also, bio-oil has a number of problems in use including high initial viscosity, instability resulting in increased viscosity or phase separation and high solids content. Much effort has been spent on upgrading bio-oil into a more usable liquid fuel, either by modifying the liquid or by major chemical and catalytic conversion to hydrocarbons. The overall primary objective was to improve oil stability by exploring different ways. The first was to detennine the effect of feed moisture content on bio-oil stability. The second method was to try to improve bio-oil stability by partially oxygenated pyrolysis. The third one was to improve stability by co-pyrolysis with methanol. The project was carried out on an existing laboratory pyrolysis reactor system, which works well with this project without redesign or modification too much. During the finishing stages of this project, it was found that the temperature of the condenser in the product collection system had a marked impact on pyrolysis liquid stability. This was discussed in this work and further recommendation given. The quantity of water coming from the feedstock and the pyrolysis reaction is important to liquid stability. In the present work the feedstock moisture content was varied and pyrolysis experiments were carried out over a range of temperatures. The quality of the bio-oil produced was measured as water content, initial viscosity and stability. The result showed that moderate (7.3-12.8 % moisture) feedstock moisture led to more stable bio-oil. One of drawbacks of bio-oil was its instability due to containing unstable oxygenated chemicals. Catalytic hydrotreatment of the oil and zeolite cracking of pyrolysis vapour were discllssed by many researchers, the processes were intended to eliminate oxygen in the bio-oil. In this work an alternative way oxygenated pyrolysis was introduced in order to reduce oil instability, which was intended to oxidise unstable oxygenated chemicals in the bio-oil. The results showed that liquid stability was improved by oxygen addition during the pyrolysis of beech wood at an optimum air factor of about 0.09-0.15. Methanol as a postproduction additive to bio-oil has been studied by many researchers and the most effective result came from adding methanol to oil just after production. Co-pyrolysis of spruce wood with methanol was undertaken in the present work and it was found that methanol improved liquid stability as a co-pyrolysis solvent but was no more effective than when used as a postproduction additive.
Resumo:
Sewage sludge was pyrolysed with 40% mixed wood, 40% rapeseed and 40% straw. The reason for the mixture of different biomass is to investigate the impact of co-pyrolysis on the upper phase of bio-oil in terms of changes to composition, elemental analysis, viscosity, water content, pH, higher heating value and acid number that could impact on their applications. The biomass was pyrolysed in a laboratory at 450 °C and bio-oil was collected from two cooling traps. The bio-oil obtained from co-pyrolysis of sewage sludge with wood, rapeseed and straw was analysed for composition using the gas chromatography mass spectrometry. The upper phase from the co-pyrolysis process was also characterised for ultimate analysis, higher heating values, water content, viscosity, pH and acid number. There was an increase in the amount of upper phase produced with co-pyrolysis of 40% rapeseed. It was also found that the upper phase from sewage sludge with mixed wood has the highest viscosity, acid number and lowest pH. The bio-oil containing 40% straw was found to have a pH of 6.5 with a very low acid number while the 40% rapeseed was found to have no acid number. Sewage sludge with 40% rapeseed was found to have the highest energy content of 34.8 MJ/kg, 40% straw has 32.5 MJ/kg while the 40% mixed wood pyrolysis oil has the lowest energy content of 31.3 MJ/kg. The 40% rapeseed fraction was found to have the highest water content of 8.2% compared to other fractions.
Resumo:
This thesis looks at the UK onshore oil and gas production industry and follows the history of a population of firms over a fifteen-year period following the industry's renaissance. It examines the linkage between firm survival, selection pressures and adaptation responses at the firm level, especially the role of discretionary adaptation, specifically exploration and exploitation strategies.Taking a Realist approach and using quantitative and qualitative methods for triangulation on a new data base derived from archival data, as well as informant interviews, it tests seven hypotheses' about post-entry survival of firms. The quantitative findings suggest that firm survival within this industry is linked to discretionary adaptation, when measured at the firm level, and to a mixture of selection and adaptation forces when measured for each firm for each individual year. The qualitative research suggests that selection factors dominate. This difference in views is unresolved. However the small, sparse population and the nature of the oil and gas industry compared with other common research contexts such as manufacturing or service firms suggests the results be treated with caution as befits a preliminary investigation. The major findings include limited support for the theory that the external environment is the major determinant of firm survival, though environment components affect firms differentially; resolution of apparent literature differences relating to the sequencing of exploration and exploitation and potential tangible evidence of coevolution. The research also finds that, though selection may be considered important by industry players, discretionary adaptation appears to play the key role, and that the key survival drivers for thispopulation are intra-industry ties, exploitation experience and a learning/experience component. Selection has a place, however, in determining the life-cycle of the firm returning to be a key survival driver at certain ages of the firm inside the industry boundary.