Experimental and analytical studies have been carried out to better understand production mechanisms of heavy oil under steam injection with propane and petroleum distillate as steam additives. The studies have been conducted for heavy oil from San Ardo field (12oAPI, 2800 cp at 53.3oC), under current reservoir conditions. The experiments consist of injecting pure steam, steam-propane, and steampetroleum distillate into a vertical cell containing a mixture of sand, water and San Ardo oil. The injection cell (68.58 cm long with an ID of 7.376 cm) is placed inside a vacuum jacket, set at the reservoir temperature of 53.3oC. Superheated steam at 230oC is injected at 5.5 ml/min (cold-water equivalent) simultaneously with propane or a petroleum distillate slug. The cell outlet pressure is maintained at 260 psig. Six runs were performed, two runs using pure steam, two steam-propane runs using 5:100 propane:steam mass ratio, and two steam-petroleum distillate runs using 5:100 petroleum distillate:steam mass ratio. We develop a simplified analytical model that describes steam front advancement and oil production for the 1D displacement experiments. The model incorporates heat and material balance, fillup time and Darcy’s law pertaining to the injection cell. The analytical model results are compared against the experimental data to verify the validity of the model. The main results of the study are as follows. First, experimental results indicate that compared to pure steam injection, oil production was accelerated by 30% for 5:100 propane:steam injection and 38% for 5:100 petroleum distillate:steam injection respectively. Second, steam injectivity with steam-propane and steam-petroleum distillate increases to 1.4 and 1.9 times respectively, compared with pure steam injection. Third, steam front advancement and oil production data are in good agreement with results based on the new analytical model. The analytical model indicates that the oil production acceleration observed is due to oil viscosity reduction resulting from the addition of propane and petroleum distillate to the steam. Oil viscosity at the initial temperature with pure steam injection is 2281 cp, which is reduced to 261 cp with steam-propane injection and 227 cp with steam-petroleum distillate injection.

Radiation technology can economically overcome principal problems of heavy oil processing arising from heavy oil’s unfavorable physical and chemical properties. This technology promises to increase considerably yields of valuable and environmentally satisfying products of thermal cracking; to simplify complexity of refinery configuration; and to reduce energy expenses of thermal cracking. Objectives of the present study are: ● Evaluate heavy oil viscosities with respect to absorbed dose and effect of different solvents on the viscosity of irradiated crude oil by comparing selected physical properties of irradiated samples to a non-irradiated control group; ● Investigate effect of e-beam radiation on the yields of light fractions comparing yields of radiation-thermal cracking to yields of conventional thermal cracking. The viscosity was used as an indicator of the change in the molecular structure of hydrocarbons upon irradiation. We found that the irradiation of pure oil leads to the increase of the molecular weight calculated from the Riazi-Daubert correlation. Thus, irradiation up to 10 kGy resulted in a 1.64% increase in the molecular weight, 20 kGy ─ 4.35% and 30 kGy ─ 3.28%. It was found that if irradiated oil was stored for 17 days, its viscosity increased by 14% on average. The irradiation of samples with added organic solvent in the following weight percentages 10, 5, 2.5wt.% resulted in the increase in the viscosity by 3.3, 3.6 and 14.5%, respectively. The irradiation of the sample with added distilled water also resulted in an increase in the viscosity. This increase mainly happened because the thermal component was absent in the activation energy and hydrogen, produced from radiolysis of solvent and water molecules in mixture with crude oil, and was not consumed by hydrocarbon molecules and no reduction in molecular size occurred. Implementation of radiation to the thermal cracking increased yields of light fractions by 35wt.% on average compared to the process where no radiation was present. The last chapter of this thesis discusses a profitability of installation the hypothetical radiation-thermal visbreaking unit. The calculation of profitability was performed by a rate of return on investment (ROI) method. It showed that implementation of radiation-thermal processing resulted in an increase of ROI from 16 to 60%.

An experimental study has been conducted to compare the effect of steam injection and caustic steam injection in improving the recovery of San Ardo and Duri heavy oils. A 67 cm long x 7.4 cm O.D (outer diameter), steel injection cell is used in the study. Six thermocouples are placed at specific distances in the injection cell to record temperature profiles and thus the steam front velocity. The injection cell is filled with a mixture of oil, water and sand. Steam is injected at superheated conditions of 238oC with the cell outlet pressure set at 200 psig, the cell pressure similar to that found in San Ardo field. The pressure in the separators is kept at 50 psig. The separator liquid is sampled at regular intervals. The liquid is centrifuged to determine the oil and water volumes, and oil viscosity, density and recovery. Acid number measurements are made by the titration method using a pH meter and measuring the EMF values. The interfacial tensions of the oil for different concentrations of NaOH are also measured using a tensionometer. Experimental results show that for Duri oil, the addition of caustic results in an increase in recovery of oil from 52% (steam injection) to 59 % (caustic steam injection). However, caustic has little effect on San Ardo oil where oil recovery is 75% (steam injection) and 76 % (caustic steam injection). Oil production acceleration is seen with steam-caustic injection. With steam caustic injection there is also a decrease in the produced oil viscosity and density for both oils. Sodium hydroxide concentration of 1 wt % is observed to give the lowest oil-caustic interfacial tension. The acid numbers for San Ardo and Duri oil are measured as 6.2 and 3.57 respectively.

Texte remanié de: Thèse de doctorat--Sociologie--Paris 5, ca 2007. / Bibliogr. p. 349-350 et 354-364. Discogr. p.350-353. Webliogr. p. 354. Glossaire.

Thesis (M.Sc. Agric)(Soil Science))--University of Pretoria, 2009. / Includes summary. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.

Traditional remediation techniques in removing toxic metal contaminants using physical and chemical methods are expensive and may cause other forms of damage to the environment, comparing with these techniques bioremediation can serve as an inexpensive, effective and environmental friendly remediation method. This thesis mainly discusses different bioremediation techniques and identifies possible areas in Hong Kong for bioremediation and suggests bioremediation methods for each potential area. Bioremediation of toxic metals is the use of microorganisms, plants, or even larger sized organisms to decontaminate sites with toxic metals. Bioremediation includes phytoremediation, microremediation and vermiremediation which use plants, microorganisms and earthworms to remediate contaminated environments respectively. The 4 most common mechanisms in phytoremediation of toxic metals are phytoextraction, phytofiltration, phytovolatilization and phytostabilization. Phytoremediation are used frequently for remediation around the world and its development includes using well-understood technology and genetic engineering to increase its effectiveness. Microremediation is another promising technology in bioremediation of toxic metals and consists of 6 major mechanisms which are biosorption, bioaccumulation, biotransformation, bioleaching, biomineralization and microbially-enhanced chemisorption of metals. Microremediation is mainly in research phase and its development includes identifying new species, combining with phytoremediation and genetic engineering. Vermiremediation is another rapidly developing technique in bioremediation of toxic metals, assisting other bioremediation by burrowing actions of earthworms and its excretion, and accumulating toxic metals inside their bodies. Vermiremediation is also in research phase but it is rapidly developing. Generally, bioremediation is around 60% cheaper than traditional remediation methods and no pollutants are emitted during the process. However the remediation process is slow and generally takes longer than a year. Sources of toxic metals in contaminated areas in Hong Kong are mainly due to historic industrial discharge although present activities also contribute. Potential areas include sites for electronic waste activities, sediments of Kwun Tong typhoon shelter and sediments of Tolo Harbour. / published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Heavy-metals exert considerable stress on the environment worldwide. This study assessed the resistance to and bioremediation of heavy-metals by selected protozoan and bacterial species in highly polluted industrial-wastewater. Specific variables (i.e. chemical oxygen demand, pH, dissolved oxygen) and the growth/dieoff- rates of test organisms were measured using standard methods. Heavy-metal removals were determined in biomass and supernatant by the Inductively Couple Plasma Optical Emission Spectrometer. A parallel experiment was performed with dead microbial cells to assess the biosorption ability of test isolates.

Abstract In this study, the removal of Pb(II) from aqueous solutions by tassel powder was studied and optimised. Batch experimentswere conducted on simulated solutions using tassel powder adsorbent and the effects of contact time, pH and concentration on the extent of Pb (II) removalwas studied. Equilibrium and kinetic models for Pb(II) sorption were developed by considering the effect of contact time and concentration at optimum pH 4 and fixed temperature(25 ◦C). The Freundlich model was found to describe the sorption energetics of Pb(II) on tassel more fully than the Langmuir. A maximum Pb(II) loading capacity of 333.3 mg/g on tassel was obtained. The adsorption process could be well described by both the Langmuir and Freundlich isotherms with R2 values of 0.957 and 0.972, respectively. The kinetic parameters were obtained by fitting data fromthe effect of contact time on adsorption capacity into the pseudo-first, pseudo-second-order and intra-particle diffusion equations. The kinetics of Pb(II) on tassel surface was well defined using linearity coefficients (R2) by pseudo-second-order (0.999), followed by pseudo-firstorder (0.795) and lastly intra-particle diffusion (0.6056), respectively. The developed method was then applied to environmental samples taken fromborehole waters contaminated with mine wastewater. The removal of Pb (ND-100%), Se (100%), Sr (5.41–59.0%),U(100%) and V (46.1–100%)was attained using tassel. The uptake of the metals from environmental samples was dependent on pH, ionic strength and levels of other competing species.

A b s t r a c t In this study, the removal of Pb(II) from aqueous solutions by tassel powder was studied and optimised. Batch experimentswere conducted on simulated solutions using tassel powder adsorbent and the effects of contact time, pH and concentration on the extent of Pb (II) removalwas studied. Equilibrium and kinetic models for Pb(II) sorption were developed by considering the effect of contact time and concentration at optimum pH 4 and fixed temperature(25 ◦C). The Freundlich model was found to describe the sorption energetics of Pb(II) on tassel more fully than the Langmuir. A maximum Pb(II) loading capacity of 333.3 mg/g on tassel was obtained. The adsorption process could be well described by both the Langmuir and Freundlich isotherms with R2 values of 0.957 and 0.972, respectively. The kinetic parameters were obtained by fitting data fromthe effect of contact time on adsorption capacity into the pseudo-first, pseudo-second-order and intra-particle diffusion equations. The kinetics of Pb(II) on tassel surface was well defined using linearity coefficients (R2) by pseudo-second-order (0.999), followed by pseudo-firstorder (0.795) and lastly intra-particle diffusion (0.6056), respectively. The developed method was then applied to environmental samples taken fromborehole waters contaminated with mine wastewater. The removal of Pb (ND-100%), Se (100%), Sr (5.41–59.0%),U(100%) and V (46.1–100%)was attained using tassel. The uptake of the metals from environmental samples was dependent on pH, ionic strength and levels of other competing species.