2\(^n\)\(^d\)-generation bioethanol can be produced from cellulose fraction present in lignocellulosic biomass and has become a significant research focus due to its potential for replacing fossil fuels and decreasing greenhouse gases emissions. In order to produce 2\(^n\)\(^d\)-generation bioethanol, biomass processing is required in order to access cellulose within lignocellulose and convert it into glucose. However, an efficient cost-effective and environmental-friendly process has not been achieved. The aim of this work was to produce glucose from purified cellulose from \(Miscanthus\) \(x\) \(giganteus\), an energy crop. The lignocellulosic biomass was selectively fractionated into its main components, hemicellulose, lignin and cellulose, after extractions using ‘green’ processes in a biorefinery approach. Hydrolysis of the cellulose-enriched fibres into glucose was evaluated using subcritical water (SBW) in a batch reactor at temperatures from 190-320oC, residence times from 0-54min and biomass loading from 0.5-6.4% (w/v). The process used for cellulose purification had significant effect on glucose production by SBW, and higher glucose yields were achieved at higher temperatures and shorter residence times. Glucose was used for bioethanol production. Although the formation of inhibitors during SBW hydrolysis could not be prevented, fermentation could be performed in the presence of these compounds at some conditions, with high ethanol yields.

Stirred vessels are used in a wide variety of process industries such as fine chemicals, pharmaceuticals, polymers and foods. In order to design efficient mixing vessels, a deep understanding of the blending processes is required. In cases where the fluid is not completely transparent, traditional optical laser based techniques are ineffective. One of the most promising techniques to study opaque systems is based on the detection of a tracer that emits gamma rays. Positron Emission Particle Tracking (PEPT) has been developed at the University of Birmingham and has been used in a wide range of applications including stirred tanks. However, for agitated vessels, any attempt of validation of the PEPT technique versus other techniques cannot be found. Hence, this work aims to validate and explore the potential of Lagrangian data in a well known mixing system such as a standard baffled vessel stirred by a Rushton turbine. As part of the validation, comparison with Eulerian PIV/LDA data has been also undertaken and some underestimation of the high velocities in the system was found in the impeller region. By using a selective interpolation algorithm of the tracer locations, this problem was greatly reduced although a perfect match with optical technique is not feasible. As further contribution to Lagrangian studies of mixing processes, Computational Fluid Dynamics (CFD) simulations have been undertaken to give both Eulerian and Lagrangian velocities and particle paths. However, it has been shown that traditional approaches to Lagrangian numerical simulation are unable to produce good trajectories that can be compared to experimental data. A novel three-step approach was suggested and implemented in order to achieve good paths, which then have been compared to the experimental trajectories. Qualitative and quantitative analysis of experimental Lagrangian data showed that the trajectories are erratic and follow random paths; furthermore, frequency analysis applied to portions of trajectories does not reveal any dominant low frequency in the system. Finally, circulation studies were undertaken in order to characterise mixing processes. This focused on tracking the tracer every time it leaves and returns a control volume proving the value of analysing time and return length distributions, since it was possible to compare the circulation times achieved in PEPT with published work. The trajectography approach used in this work is the first attempt at using trajectories from PEPT as a tool to characterise mixing performance rather than only using the data to find Eulerian velocities and vector plots.

Biodiesel (fatty acid methyl ester, FAME) is a renewable diesel fuel made from vegetable oil and methanol. The two main problems with the process are disposal of waste streams and product purity. This thesis studies biodiesel process improvements, especially glycerol conversion to hydrogen and improved mass transfer to increase ester yield. Experiments on steam reforming with glycerol and waste water over a platinum alumina catalyst were used to convert the combined waste product streams of a biodiesel plant. Mass spectroscopy with internal standard was chosen to measure reformer gas yield and conversion. The glycerol steam reforming was shown to depend on several reaction variables. Therefore a solid oxide fuel cell was used as a sensor to measure the effects. The results showed that good syngas yield, conversion and reformer life could be obtained using this process. The purity of the biodiesel product was examined using real-time optical microscopy and gas chromatography to fit the FAME standard EN14214. It was observed that droplet size had a major influence on reaction end point and that the reaction was mass-transfer limited. This observation was confirmed by developing a mass-transfer based reaction model using the data from the batch reactor which agreed with results from other researchers. The model predicted better conversion with more mixing intensity. Finally, on the basis of these results, a high mixing intensity continuous reactor was developed which achieved the 96.5% standard with high flow rate and short reactor length. The conclusion was that significant cost effective improvements could be made to the conventional FAME process.

Over the last few decades, static mixers have been used commonly in different industries mainly for mixing of high viscosity fluids. The performance of this group of mixers has been investigated by many groups via numerically based studies. Experimental studies, however, are limited, particularly for measurement of the flow fields with fluids of complex rheology; there is also a lack of fundamental understanding of laminar flow and mixing performance for such duties. This is essential in order to gain improved design procedures for the selection and operation of the mixers in blending applications.

Control release from biopolymer is an important issue for flavour perception following to reduce flavour content such as salt in food formulation without any tangible change in taste. The experiments presented release behaviour from low acyl gellan gum gel. Attempts were focused to find a link between mechanical properties and microstructure of the gel. After conducting the compression tests, a number of parameters were investigated and the consist of the effect of the gellan concentration, salt concentration and cyclic compression on the mechanical properties of the gel. According to the results, mechanical properties of the gellan gels were remarkably affected by the gellan concentration, salt concentration and cyclic compression. It was shown that the gellan concentration, salt concentration and cyclic compression play a main role on the microstructure of the gel. The release experiments were carried out using uniaxial and cyclic compression to investigate the salt and riboflavin release from the gellan gel to identify the parameters which play a role on release from the gellan gel. Release experiments have shown that release profile is affected by the gellan concentration, salt concentration and number of cyclic compression. Results demonstrated that release profile can be affected by molecular weight of the releasable material.

Magnetic bioseparations based on non-porous adsorbents offer a low-fouling alternative to the porous materials required by conventional adsorbent separation techniques. Interest in magnetic bioseparations has been limited by the high cost of suitable magnetic absorbents. In this study a variety of techniques - including Ce(IV) initiation, surface ATRP and sulfonyl activation – were used to graft ion-exchanging polyelectrolyte surfaces on low cost non-porous polyvinyl alcohol-magnetite supports. Grafting of poly(2-vinyl pyridine) and poly(methacrylic acid) was fully characterised using solid and liquid state FTIR. Dense polyelectrolyte layers were seen, with Ce(IV) grafted layers accounting for up to 49% of grafted support mass. Values for ATRP and tresyl activations were 41% and 25% of support mass respectively. These included layers which correspond to the brush regime (2R\(_f\)/D > 8), as determined by Flory Radius calculations. The above matrices were subsequently analysed with bind and elute studies using a model mixture of acidic and basic proteins. Switchable ion-exchange behaviour was demonstrated, with anion binding capacity >25 mg/g support at pH 5 and cation binding >25 mg/g seen for Ce(IV) grafted supports. Improved elution by pH was also seen, with up to 73% of bound lysozyme removed during a single elution at pH 5.

The regulatory framework in which pharmaceutical companies have to work has changed significantly since the late 1990’s. The development and implementation of risk based approaches to processing pharmaceutical powders allows the pharmaceutical manufacturers the freedom to adopt real-time release for their products whist reducing the regulatory burden for both the statutory bodies and the manufacturers. This thesis has been a collaboration between Buck Systems and the University of Birmingham School of Chemical Engineering to evaluate and develop methods which would enhance the way in which Buck Systems can, in co-operation with their clients, enhance their understanding of how powder properties affect their products that are used in pharmaceutical manufacturing to better comply with the changes in the regulatory environment. To this end simple and quick screening methods for characterisation of customers’ powders with a view to identifying potential problems prior to blending tests have been developed to replace the current ad hoc approach. These include the use of tests that have been relied on historically as well as newer, more universal and robust techniques such as automated shear cells and powder rheometers. Detailed characterisation trials have shown where these techniques can be successfully applied and where their limitations lie. Further work has shown how powder systems can be better evaluated within the existing HAZOP framework. Specific evaluation of the hopper design methodology has resulted in the development of an expert system to enable the rapid sensitivity analysis of design options. In addition the limits of the hopper design method have been explored and some limitations identified where significant overdesign may occur. The evaluation of content uniformity in a laboratory scale blender using specialist Positron Imaging equipment available at the University of Birmingham has also been undertaken. The unique study of the blender contents using Positron Emission Tomography has provided a range of insights into the way binary and ternary powder systems interdisperse.

One of the major drawbacks to the large scale application of magnetic support based separations in biotechnology is the astronomic price of large quantities of commercially available magnetic support materials. The aim of this work has been to develop a simple, fast and scalable ‘one-pot’ manufacturing route to cheap magnetic adsorbents to be used in High-Gradient Magnetic Fishing, Magnetically Enhanced Press Filtration and Magnetically Enhanced Centrifugation systems. An inverse liquid-liquid two phase polymerization technique employing low cost chemicals combined with the use of a rotor stator type high shear mixer was systematically investigated. When the ‘ideal’ manufacturing conditions were identified, nonporous superparamagnetic composite supports (3 .m average size; M\(_s\): 34 A m\(^2\) kg\(^{-1}\); magnetic content: 44.3%) were successfully created. Following further optimization, the ‘one-pot’ manufacturing procedure was used to produce anion exchange magnetic adsorbents, and their binding capacity was determined using human serum albumin as a model species (Q\(_{max}\)=46.1 mg of protein per gram of adsorbent; K\(_d\)=2.52 .M). Further attempts to create cation exchange magnetic supports were unsuccessful mainly due to chemical incompatibility issues between the reaction chemicals and the ferrofluid used.

Lipid oxidation is a major issue for food manufacturers resulting in alteration of taste and appearance of product. In recent years, the food industry has been facing a tremendous pressure from consumers for using chemical agents to prevent lipid oxidation. In this study a novel approach to reduce lipid oxidation in oil-in-water emulsions has been taken and involves the manipulation of the emulsions' interfacial microstructure. Initially, oil-in-water emulsions were prepared with silica particles. The lipid oxidative stability was improved by up to 50%, compared with the emulsions stabilised by surfactant. However, silica particles are not “label friendly” hence; Modified Starch and colloidal Microcrystalline Cellulose were used as the “food-grade” Pickering particles. These samples had great stability against coalescence and the oxidation rate was reduced by up to 75%, compared with the emulsions stabilised by surfactant. The potential ability of fat crystal at the droplet interface to enhance the oxidative stability was also investigated. This was carried out by stabilising oil-in-water emulsions with saturated monoglyceride in the presence of xanthan gum. A bench scale scraped-surface heat exchanger was used to produce these emulsions. Solid fat crystals “shells” were created around the oil droplets by oscillating the temperature during emulsification. It was shown that these “shells” were capable of inhibiting the lipid oxidation by preventing pro-oxidants to come into close contact with the oil droplets.

The objective of this work is to compare the performance of different geometries (i.e. planar, coplanar and micro tubular) under single-chamber (mixed-reactant) solid oxide fuel cell (SC-SOFC) conditions. In this respect, these designs have been computer analyzed and it is found that the micro-tubular design eliminates the possibility of cross diffusion/convection from the counter electrode, which is an inherent disadvantage in planar and co-planar designs. This is the first experimental report describing that the micro-tubular design offers the highest fuel utilization, cell efficiency and an acceptable level of performance (under single-chamber conditions) as compared to other designs. With the help of developed numerical model (also the first one, on mixed-reactant, micro-tubular design), it is demonstrated that there is a possibility of further improvement in performance, e.g. cell positioning, micro-tube diameter and cathode morphology (its micro-structure and material) are important factors to consider. Other parameters such as, flow rate, temperature and mixing ratio are also very effective in improving the cell performance but these parameters should be carefully controlled in order to avoid their counter-effects, like, lower fuel utilization, material degradation, anode coking and oxidation-reduction. There are some other parameters such as, electrode porosity, permeability and cathode radiative emissivity, which have minimal effect in performance enhancement and it is suggested before investing time on these parameters, a net energy and cost analysis would be very helpful. There are still some issues with choosing appropriate materials for building an SC-SOFC with both an acceptable lifetime and production of electrical energy. While it has been observed that most of the problems related to material degradation are thermally driven, it would be very helpful to lower the operating temperature by using intermediate temperature SOFC materials. Further to this, long term degradation studies and performance cycling will benefit in order to determine their suitability under mixed-reactant environment.