Biodiesel is primarily produced by transesterification of edible oils. Increasing concern about using food supplies for fuel has generated interest in alternative raw materials. Furthermore, there are numerous steps between harvesting of oilseeds and final production of biodiesel that can be integrated, thereby simplifying the process and making it more suitable for distributed production. Hence, in this study, the production of biodiesel via in situ transesterification of non-edible Jatropha curcas seed has been investigated. The main aim was to investigate the parameters of the process, with a view to reducing the substantial excess of methanol required. A significant secondary aim was to investigate the possibility of utilising other compounds that come out from the process. “Design of experiments” was employed to study the parameters at lab-scale, with the matrix boundary being determined beforehand using one-at-a-time experiments. The reduction of methanol excess was attempted by use of two co-solvents, hexane and diethylmethane (DEM), and by replacing methanol with methyl acetate. It was found that in situ transesterification run using particle sizes below 0.71 mm, a 400:1 molar ratio of methanol to oil, 60 minutes, and a minimum of 300 rpm mixing intensity yielded the highest biodiesel yield of 83 wt %. NaOH concentration and reaction temperature were not found to be significant variables, and were set at 1.0 N and 30oC respectively. DEM was a more effective co-solvent than hexane. The addition of DEM to the process at 400:1 molar ratio experiment increased the yield from 83 to 92 wt %. When methyl acetate was used to replace methanol, the requirement of molar ratio of solvent:oil reduced significantly to 175:1 to achieved 86.8 wt% of biodiesel. The solid meal was shown to contain substantial amounts of protein, making it a valuable co-product stream. Previously J. curcas meal had had little value as animal feed due to its toxicity, but this may be reduced or removed by this process.

Biodiesel is a renewable alternative to petro-diesel, derived from vegetable oils and animal fats. The use of biodiesel in place of petro-diesel leads to reduced emissions of greenhouse gases, especially CO2, and ensures energy security. The most commonly used technology for biodiesel production is based on a homogeneously catalysed liquid phase reaction. The disadvantages of this process are the ongoing costs of catalyst replacement, the large number of downstream purification steps and production of low quality glycerol with consequently low market value. In principle, heterogeneous catalysts can solve these problems. This research demonstrates that homogeneous alkali-catalysed biodiesel production was possible at an industrially acceptable level of conversion (> 96%) in ~ 5 min residence time, requiring a combination of high catalyst concentration and good mixing. Both the experimental and model simulations results clearly showed that rapid biodiesel production (reaction times below 2 min) at economically viable conversions can be achieved by increasing base catalyst and methanol concentrations without significant problems due to excess soap formation, even in the presence of water and free fatty acids. A heterogeneous strontium zirconate based (SZB) catalyst showed substantial activity towards rapeseed oil transesterification, but there was significant loss in activity with or without the presence of water due to leaching of the active sites, Sr(OH)2, into the methanol phase. The SZB catalyst cannot be re-used for triglyceride transesterification, as it acts in a similar manner to conventional homogeneous alkali catalysts. A PrSO3H-SBA-15 catalyst was active for carboxylic acids esterification with methanol, with the reaction rates increasing with reaction temperature and methanol molar ratio, but decreasing with water content and carboxylic acid chain length. Steric effects increased with carboxylic acid chain length, causing reductions in the esterification rates and turnover frequency. PrSO3H-SBA-15 has very narrow pores (5.1nm) that are not large enough for significant triglyceride transport. Therefore, PrSO3H-SBA-15 with expanded pore size, functionalised on a hydrophobic support would be required for simultaneous esterification of free fatty acids and triglyceride transesterification. Finally, a mesoscale oscillatory baffled reactor (meso-OBR) was constructed and used to suspend and screen solid catalysts for transesterification and esterification reactions, significantly reducing reagent required and waste generated due to the small volume (~10mL). This work is the first example of systematic screening of a solid-liquid-liquid reaction system in a meso-OBR. Continuous screening in the meso-OBR permits detailed kinetic studies, rapid optimisation of reaction conditions, and assessment of the reusability of the catalyst in a single experiment as opposed to multiple experiments in conventional batch reactor screening.

The proton exchange membrane water electrolyser (PEMWE) is a promising technology for the production of hydrogen from water. The oxygen evolution reaction (OER) has a high over potential cf. with the hydrogen evolution reaction and is one of the main reasons for the high energy demand of the electrolyser. RuO₂ and IrO₂ are the most active catalyst for OER, but are costly, making the electrolyser system expensive. In general, it is important to use stable, active and cheap catalysts in order to make a cost efficient electrolyser system. Supporting the active catalyst on a high surface area conducting support material is one of the approaches to reduce the precious metal loading on the electrode. Antimony tin oxide (ATO) and indium tin oxide (ITO) were studied as possible support materials for IrO₂ in the PEMWE anode prepared by the Adams method. The effect of the support material on the surface area, electronic conductivity, particle size and agglomeration were investigated. The IrO₂ showed highest conductivity (4.9 S cm-¹) and surface area (112 m2 g-¹) and decreased with the decrease in the IrO₂ loading. Using the catalysts in the membrane electrode assemblies (MEA) with Nafion®-115 membranes, at 80°C showed that the catalyst with better dispersion and conductivity gave better performance. The unsupported IrO₂ and 90% IrO₂ supported on ATO and ITO showed the best performance among all the catalysts tested, achieving a cell voltage of 1.73 V at 1 A cm-². A lower IrO₂ loading decreased the conductivity and surface area. The IrO₂ particle size and bulk conductivity of the supported catalyst significantly influenced the MEA performance. Overall, it is important to maintain a conductive network of IrO₂ on the non-conducting support to maintain the bulk conductivity and thus reduce the Ohmic potential drop. Although RuO₂ is the most active catalyst for OER, it lacks stability on long term operation. RuxNb1-xO₂ and IrxNb1-xO₂ catalysts were synthesized and characterized, to try to develop stable electrodes for PEMWE. However the Adams method of catalyst synthesis formed a sodium–niobium complex making it unsuitable for preparation of Nb based catalysts. In both Adams and hydrolysis methods of synthesis, the addition of Nb ₂O₅ decreased the anodic charge and electronic conductivity of the catalyst due to the dilution of the active RuO₂. The RuO₂ catalyst showed the best performance in MEA evaluation compared to the bimetallic catalyst (1.62 V and 1.75 V @1 A cm-² for RuO₂(A) and RuO₂(H) respectively). A higher stability for bimetallic catalyst compared to the monometallic catalysts was obtained from the continuous CV cycling and MEA stability test.

It is anticipated that resources from extra-heavy oils and bitumen may resolve the expected future escalation in oil demand. Such oils are usually recovered by thermal methods, however these can be energy intensive, especially for reservoirs with thin net-pay or those bounded with large aquifers or gas caps. This is primarily due to excessive heat losses. On the other hand, VAPour EXtraction of heavy oil (VAPEX) is a more energy-efficient, economically attractive and pollution-free alternative, especially for these problematic scenarios. Despite all the potential benefits of this process, there are many uncertainties associated with the actual physics of the process. The question as to whether the oil drainage rates are sufficient for the mechanism to be economically feasible for field scale application remains unanswered. Prediction of field scale recovery factors by numerical simulation is challenging since a very fine grid is needed to ensure that the physical diffusion dominates the numerical diffusion and then to model the subsequent gravity drainage. Thus, there is a tendency to rely upon the Butler-Mokrys (1989) analytical equation to estimate oil rates. A further uncertainty in field scale application, which has only been investigated in a few studies, is the impact of geological heterogeneity on the process, since this can influence the solvent-oil dispersive mixing as well as the shape of the solvent chamber. This research first investigated the oil drainage rates with VAPEX by performing a series of laboratory experiments in both homogenous and heterogeneous systems (including layered and single discontinuous shales). All experiments were performed in well-characterized glass bead packs using glycerol and ethanol as analogues of heavy oil and solvent, respectively. The porous medium and fluid properties were measured independently. The experimentally measured rates were compared to the estimates derived from the Butler-Mokrys (1989) analytical model. In addition, numerical simulations were performed to validate whether the physical diffusion boundaries were captured correctly. Our experiments revealed that the Butler-Mokrys analytical model substantially underestimated the drainage rates in all cases, even when the effects of convective dispersion and end-point density difference were factored in. Results from the heterogeneous models further suggested that layering may not reduce VAPEX oil drainage rates significantly. The performance in systems with layers and discontinuous shale barriers, however, was less than in homogenous models with higher or equivalent permeabilities. The numerical simulations, therefore, under-predicted the physical oil drainage rates, although the pattern of solvent-oil distribution was correctly captured. The research was then extended from lab-scale experiments to field-scale numerical investigations, using a fine grid, high resolution model with realistic petro-physical properties. The solvent-oil PVT were based on real field properties. Three key criteria were examined: the oil production rates and the recovery factors that it is possible to achieve; the full range of static parameters influencing VAPEX, and; identification of the most sensitive parameters (i.e. reservoir thickness (h), vertical permeability (kv/kh) and average arithmetic permeability). In addition, we compared the performance of VAPEX against Steam Assisted Gravity Drainage (SAGD). These, field scale numerical simulations revealed that VAPEX oil extraction rates incorporating diffusional mixing alone were insufficient for the mechanism to be feasible. Although incorporating single-well tracer test (SWTT) dispersivities into the numerical simulations significantly improved the recovery rates, they still remained unacceptably low.

Rice husks from Brunei were subjected via intermediate pyrolysis for bio-oil production. Two main objectives were set out for this study. The application of intermediate pyrolysis on Brunei rice husk for the production of bio-oil is the main objective of this experiment. Characterisation of the rice husks was inclusive as a pre-requisite step to assess the suitability as feedstock for production of liquid fuels. Following on from the characterisation results, a temperature of 450°C was established as the optimum temperature for the production of bio-oil. A homogenous bio-oil was obtained from the pyrolysis of dry rice husk, and the physicochemical properties and chemical compositions were analysed. The second objective is the introduction of catalysts into the pyrolysis process which aims to improve the bio-oil quality, and maximise the desired liquid bio-oil properties. The incorporation of the catalysts was done via a fixed tube reactor into the pyrolysis system. Ceramic monoliths were used as the catalyst support, with montmorillonite clay as a binder to attach the catalysts onto the catalyst support. ZSM-5, Al-MCM-41, Al-MSU-F and Brunei rice husk ash (BRHA) together with its combination were adopted as catalysts. Proposed criterions dictated the selection of the best catalysts, subsequently leading to the optimisation process for bio-oil production. ZSM-5/Al-MCM-41 proved the most desirable catalyst, which increases the production of aromatics and phenols, decreased the organic acids and improved the physicochemical properties such as the pH, viscosity, density and H:C molar ratios. Variation in the ratio and positioning of both catalysts were the significant key factor for the catalyst optimisation study.

The Government of India has planned to substitute 20% (12-15 million metric tonnes) of fossil diesel with biodiesel, produced using non-edible oils by 2017. In addition to Jatropha, more than 300 oil-bearing trees have been identified as biodiesel feedstock in India, of which, around 800 species inhabit Karnataka State.

The problem of vaporizing flow of liquefied natural gas (LNG) through porous or penetrable media has received very little attention despite its importance in assessing the performance and risk-based safety of large membrane tank LNG ships under barrier leakages. In this work, a fluid flow model is proposed and used to analyse the vaporizing flow behaviour of LNG through soil and glass wool porous materials. Furthermore, a modified vaporizing liquid pool model is implemented and used to examine the problem of vaporizing LNG pool on non-penetrable solid substrates. We employed an explicit, finite difference and a fourth-order Runge-Kutta algorithms coded in FORTRAN to respectively solve the flow and pool models. Both models were successfully verified and validated by comparisons to experimental data, analytical solutions, and to predictions of a commercial software (TOUGH2). Results from the vaporizing flow and pool analyses demonstrate that, for some of the applications considered, the liquid is expected to reach considered threshold depths, seep through the porous layer and contact, contaminate and/or embrittle surrounding natural or engineered systems. For the specific application to LNG cargo containment systems (or cargo tanks), this work has shown that there are safety risks associated with LNG leakage, which are ultra-low temperature of the inner hull, cryogenic damage and subsequent failure of the cargo containment system. Thus, for any LNG membrane cargo containment system to continue to be safe and secure, the various structural members of the insulation system should be designed and equipped with new and improved materials that possesses the necessary mechanical and thermophysical properties to maintain and/or improve the critical temperature standard and low-temperature performance of these systems. Further work should consider additional experimental evidence in order to fully validate and establish that solution predictions by the proposed models are describing the actual physical effects.

Sand production in the life of oil and gas reservoirs is inevitable, as it is co- produced with oil and gas from the reservoirs. Sand deposition in petroleum pipelines poses considerable risk to the production of oil and gas. This study investigates the effect both of sand particle diameter and concentration on minimum transport conditions in single phase and multiphase horizontal pipelines through experimental methods. This study defines the minimum transport condition (MTC) for sand grains under stratified two-phase flow regimes, as the combined minimum gas and liquid velocities at which all sand particles have sufficient energy to keep them moving in the liquid phase along the pipe. In this study, careful analyses based on experimental observations were made producing several conclusions. Based on the analysis, it was found that sand of different particle diameters and concentrations exhibits similar behaviours in single phase flow and stratified two-phase flow in horizontal pipes. Furthermore, in stratified two-phase flow, sand particles were transported within the liquid film and never observed crossing into the gas phase or transported across the gas- liquid interface; however, an increase in gas velocity tends to cause an increase in liquid velocity which in turn increases the velocity of the sand particles in stratified two-phase flow. Studies carried out on the effect of particle diameter and concentration on MTCs in both single phase (water) and stratified two-phase flows (air-water) in horizontal pipes showed that MTC increases with increases in particle diameter for the same concentration and also increases as the concentration increases for the same particle diameter. Sand sensors were used in this study for the purpose of sand monitoring and detection in single phase (water) and stratified two-phase flow in horizontal pipes. The sensors were flush-mounted at the bottom of the pipe. These sensors are commonly used to measure the thickness of a film in multiphase flow but have not been used before for monitoring and detecting sand both in single phase and multiphase flows. In this work the sensors were applied in monitoring and detecting sand in single phase and multiphase flows; they were found to be capable of monitoring and detecting sand in a conducting liquid in both single phase and stratified two-phase flows. Measured pressure gradients for sand-water flow at MTC were compared with measured pressure gradients for sand-air-water flow for the same particle diameter and concentration; it was found that there was a difference between the two pressure gradients. The pressure gradient of sand-water flow at MTC was higher than the pressure gradient of sand-air-water flow at MTC. For this reason, King et al.’s (2001) pressure gradient approach cannot be used to design wet gas pipelines. Modified concentration (v/v) correction correlation is proposed to predict sand transport at MTC in air-water. The correlation accounts for low concentration of sand (5.39E-05 to 4.90E-04v/v) in air-water flow. The proposed correlation predicted fairly when compared with the experimental results at MTC.

This thesis presents the research on the development and optimisation of energy efficient adsorbent monoliths and foam-monoliths for the removal of carbon dioxide (CO2) and other contaminants such as hydrogen sulfide (H2S) and water (H2O) vapour from the biogas stream. Zeolite and MIL-101(Cr) monoliths and carbonate-based zeolite foammonoliths of novel chemical formulations have been manufactured, characterised and tested for adsorption. Using the prepared adsorbent monoliths as models, their kinetic adsorption and gas flow dynamic performances have also been evaluated and compared with packed beds of commercially available adsorbent beads. The research mainly comprised of three parts. The first part was concerned with the manufacturing, characterising and optimising the adsorbent monoliths and foammonoliths. The adsorbent monoliths and foam-monoliths have been fabricated successfully using the unique paste extrusion technique described in this thesis. This includes monoliths of 13X zeolite, LiLSX zeolite, 5A zeolite, clinoptilolite and MIL-101(Cr) and foam-monoliths of K2CO3/13X zeolite and Na2CO3/13X zeolite. The incorporation of a decomposable pore former such as Licowax C micropowder PM into their paste formulations were found to improve their structural porosity, adsorption performance and mass transfer. It has been found that the best type of adsorbent structure for CO2 adsorption were 13X zeolite and purified MIL-101(Cr) monoliths and K2CO3/13X zeolite foam-monoliths. The CO2 adsorption performances of purified MIL-101(Cr) monoliths and K2CO3/13X zeolite foam-monoliths have been shown to be comparable to a packed bed of 13X zeolite beads (in terms of effectiveness of the adsorbent bed utilisation and equilibrium adsorption capacity on mass basis, respectively). This confirmed that the prepared adsorbent monoliths and foam-monoliths were potential adsorbent structures for CO2 adsorption. The second part involved testing the prepared adsorbent monoliths and foammonoliths with single (such as CO2, CH4 and H2S) and mixed (such as CO2/CH4 and CO2/CH4/H2O vapour) gases under different operating conditions to assess their dynamic adsorption performances for biogas upgrading. 13X zeolite and MIL-101(Cr) monoliths and K2CO3/13X zeolite foam-monoliths were used as model adsorbent structures in single and mixed gas adsorption experiments. The study has shown that 13X zeolite monoliths and K2CO3/13X zeolite foam-monoliths have excellent adsorption performances for CO2, H2S and H2O vapour and they could upgrade the biogas to a high quality (i.e., up to about 98% vol. CH4). For purified MIL-101(Cr) monoliths, it was discovered that they have relatively good adsorption performance for CO2, H2S, CH4 and H2O vapour and they could upgrade the biogas to a moderate quality (i.e., up to about 67% vol. CH4). In both humid and dry conditions, K2CO3/13X zeolite foam-monoliths were found to have the highest selectivity of CO2 over CH4 compared to 13X zeolite and purified MIL-101(Cr) monoliths. The third part was related to the evaluation and comparison of kinetic adsorption and gas flow dynamic performances of the prepared adsorbent monoliths with those of packed beds of adsorbent beads. In these studies, LiLSX zeolite monoliths and beads were used as model adsorbent structures. The kinetic adsorption study has discovered that LiLSX zeolite monoliths have slightly higher overall mass transfer resistance than packed beds of LiLSX zeolite beads. It has been shown that the overall mass transfer resistance in monoliths could be reduced by decreasing the channel diameter and increasing the wall thickness. The gas flow dynamic study found that the mass transfer in monoliths was not contributed by the axial dispersion of gases and this was in contrast to the mass transfer in packed beds. LiLSX zeolite monoliths were found to have lower pressure drop compared to packed beds of LiLSX zeolite beads. This showed that the biogas upgrading process would be more energy efficient using adsorbent monolith/foammonolith systems compared to packed bed systems.

Sustainable development has become a key ideal which must be translated into the real world, leaving scientists and engineers confronted with meeting demanding tasks of far-reaching environmental, economic and social objectives. Products must be developed that can be manufactured in environmentally acceptable ways with minimum consumption of energy and raw materials, whilst maintaining as favourable an ecological balance as possible [Metzger, 20011. Global drivers have led the construction industry to consider the use of recycled and waste materials to aid sustainability. A key area for development is in the use of alternative binders for asphalt. A primary target of this investigation was the development of technical knowhow for blending of bitumen and vegetable oil (both virgin and used) to produce a range of equivalent penetration grade binders referred to henceforth as Vegetex. This thesis begins by exploring and critically reviewing current applications of used vegetable oil in industry, followed by a review of current construction applications, along with present developments in asphalt mix production for pavement applications; whilst also documenting the technical development of Vegetex from exploratory laboratory work through to laying trials outlining, whilst also summarising, key features and benefits, current intellectual property status and environmental considerations. Following an in depth laboratory analysis, numerous full scale manufacturing trials were carried out. Work has shown that partial substitution of bitumen with used vegetable oil (UVO) can produce a wide range of standard binder grades, that comply with BS EN requirements for paving grade bitumen and that meet Sector Scheme 14 requirements thus enabling the product to comply with quality management systems. It has been shown that Vegetex material composites manufactured using traditional asphalt plants, delivery vehicles and laying equipment as currently used by the asphalt industry, retains similar or improved performance in compaction,