Computer control of chemical process plants with special reference to distillation

A sieve plate distillation column has been constructed and interfaced to a minicomputer with the necessary instrumentation for dynamic, estimation and control studies with special bearing on low-cost and noise-free instrumentation. A dynamic simulation of the column with a binary liquid system has been compiled using deterministic models that include fluid dynamics via Brambilla's equation for tray liquid holdup calculations. The simulation predictions have been tested experimentally under steady-state and transient conditions. The simulator's predictions of the tray temperatures have shown reasonably close agreement with the measured values under steady-state conditions and in the face of a step change in the feed rate. A method of extending linear filtering theory to highly nonlinear systems with very nonlinear measurement functional relationships has been proposed and tested by simulation on binary distillation. The simulation results have proved that the proposed methodology can overcome the typical instability problems associated with the Kalman filters. Three extended Kalman filters have been formulated and tested by simulation. The filters have been used to refine a much simplified model sequentially and to estimate parameters such as the unmeasured feed composition using information from the column simulation. It is first assumed that corrupted tray composition measurements are made available to the filter and then corrupted tray temperature measurements are accessed instead. The simulation results have demonstrated the powerful capability of the Kalman filters to overcome the typical hardware problems associated with the operation of on-line analyzers in relation to distillation dynamics and control by, in effect, replacirig them. A method of implementing estimator-aided feedforward (EAFF) control schemes has been proposed and tested by simulation on binary distillation. The results have shown that the EAFF scheme provides much better control and energy conservation than the conventional feedback temperature control in the face of a sustained step change in the feed rate or multiple changes in the feed rate, composition and temperature. Further extensions of this work are recommended as regards simulation, estimation and EAFF control.

The development and optimisation of a fast pyrolysis process for bio-oil production

A two-tier study is presented in this thesis. The first involves the commissioning of an extant but at the time, unproven bubbling fluidised bed fast pyrolysis unit. The unit was designed for an intended nominal throughput of 300 g/h of biomass. The unit came complete with solids separation, pyrolysis vapour quenching and oil collection systems. Modifications were carried out on various sections of the system including the reactor heating, quenching and liquid collection systems. The modifications allowed for fast pyrolysis experiments to be carried out at the appropriate temperatures. Bio-oil was generated using conventional biomass feedstocks including Willow, beechwood, Pine and Miscanthus. Results from this phase of the research showed however, that although the rig was capable of processing biomass to bio-oil, it was characterised by low mass balance closures and recurrent operational problems. The problems included blockages, poor reactor hydrodynamics and reduced organic liquid yields. The less than optimal performance of individual sections, particularly the feed and reactor systems of the rig, culminated in a poor overall performance of the system. The second phase of this research involved the redesign of two key components of the unit. An alternative feeding system was commissioned for the unit. The feed system included an off the shelf gravimetric system for accurate metering and efficient delivery of biomass. Similarly, a new bubbling fluidised bed reactor with an intended nominal throughput of 500g/h of biomass was designed and constructed. The design leveraged on experience from the initial commissioning phase with proven kinetic and hydrodynamic studies. These units were commissioned as part of the optimisation phase of the study. Also as part of this study, two varieties each, of previously unreported feedstocks namely Jatropha curcas and Moringa olifiera oil seed press cakes were characterised to determine their suitability as feedstocks for liquid fuel production via fast pyrolysis. Consequently, the feedstocks were used for the production of pyrolysis liquids. The quality of the pyrolysis liquids from the feedstocks were then investigated via a number of analytical techniques. The oils from the press cakes showed high levels of stability and reduced pH values. The improvements to the design of the fast pyrolysis unit led to higher mass balance closures and increased organic liquid yields. The maximum liquid yield obtained from the press cakes was from African Jatropha press cake at 66 wt% on a dry basis.

A methodology for the generation and evaluation of biorefinery process chains, in order to identify the most promising biorefineries for the EU

The topic of bioenergy, biofuels and bioproducts remains at the top of the current political and research agenda. Identification of the optimum processing routes for biomass, in terms of efficiency, cost, environment and socio-economics is vital as concern grows over the remaining fossil fuel resources, climate change and energy security. It is known that the only renewable way of producing conventional hydrocarbon fuels and organic chemicals is from biomass, but the problem remains of identifying the best product mix and the most efficient way of processing biomass to products. The aim is to move Europe towards a biobased economy and it is widely accepted that biorefineries are key to this development. A methodology was required for the generation and evaluation of biorefinery process chains for converting biomass into one or more valuable products that properly considers performance, cost, environment, socio-economics and other factors that influence the commercial viability of a process. In this thesis a methodology to achieve this objective is described. The completed methodology includes process chain generation, process modelling and subsequent analysis and comparison of results in order to evaluate alternative process routes. A modular structure was chosen to allow greater flexibility and allowing the user to generate a large number of different biorefinery configurations The significance of the approach is that the methodology is defined and is thus rigorous and consistent and may be readily re-examined if circumstances change. There was the requirement for consistency in structure and use, particularly for multiple analyses. It was important that analyses could be quickly and easily carried out to consider, for example, different scales, configurations and product portfolios and so that previous outcomes could be readily reconsidered. The result of the completed methodology is the identification of the most promising biorefinery chains from those considered as part of the European Biosynergy Project.

The transformational implementation of JSD process specifications via finite automata representation

Conventional structured methods of software engineering are often based on the use of functional decomposition coupled with the Waterfall development process model. This approach is argued to be inadequate for coping with the evolutionary nature of large software systems. Alternative development paradigms, including the operational paradigm and the transformational paradigm, have been proposed to address the inadequacies of this conventional view of software developement, and these are reviewed. JSD is presented as an example of an operational approach to software engineering, and is contrasted with other well documented examples. The thesis shows how aspects of JSD can be characterised with reference to formal language theory and automata theory. In particular, it is noted that Jackson structure diagrams are equivalent to regular expressions and can be thought of as specifying corresponding finite automata. The thesis discusses the automatic transformation of structure diagrams into finite automata using an algorithm adapted from compiler theory, and then extends the technique to deal with areas of JSD which are not strictly formalisable in terms of regular languages. In particular, an elegant and novel method for dealing with so called recognition (or parsing) difficulties is described,. Various applications of the extended technique are described. They include a new method of automatically implementing the dismemberment transformation; an efficient way of implementing inversion in languages lacking a goto-statement; and a new in-the-large implementation strategy.

Strategy making process, its content and context in small professional football clubs

This thesis examines the phenomenon of strategy. Making as practised by small professional football clubs. The study was undertaken because football clubs were perceived to have problems with strategy-making and because it was believed that the specific circumstances of football clubs could be outside the range of views covered by conventional views of strategy-making. The characteristics of the club environment are its uncertainty and unpredictability, simultaneous competition and co--operation, strong regulations, and a not-for-profit orientation. Small clubs in particular face a constant struggle for financial viability and survival, due in part to split business and playing objectives. The study was designed to establish the extent and nature of the difficulties clubs experience with a view to preparing the way for creating practical guidance on ways to overcome them. Clearly, in order to survive in the long term, small professional football clubs require very effective strategic decisions. This study has addressed this issue by inquiring into the nature of strategy making for these organisations with the objective to establish the general direction in which the football clubs in question should be moving. As a result, the main research question to guide this investigation was determined as: Why do small professional football clubs have difficulties making strategies. The investigation was based on an analysis the concept of strategy and its elements, the strategic vision and objectives, the process by which strategic action comes about, the strategic action itself, and the context within which this action occurs. Data has been collected, analysed and interpreted in relation to each of these elements. Together with a wide variety of published material, 20 small football clubs have been sampled and personal interviews were conducted with board members of those clubs. The findings indicate that small football clubs do indeed experience considerable difficulties in making strategies, the reasons for which lie both in the characteristics of their competitive environment and their approaches to strategy-making. The competitive environment is characterised by a cartel-like structure with a high degree of regulation, high levels of uncertainty, little control over the core product or the production process, short-term business cycles and a close geographical link between a club with its local market. The management of clubs is characterised by the need to balance conflicting sporting and business objectives. Formal planning techniques are of little use in the small football club context as decision-making processes have a strong political character and the development of novel strategies is hindered by a strong conservative, industry paradigm and a lack of financial and managerial resources. It is concluded that there is no simple advice to be given to clubs, as they must re-examine the relationship between their playing and business objectives to create a unified and workable approach.

The influence of utilising government initiatives, servicing foreign MNCs and internationalisation on strategic planning process of local companies in Singapore

This research focuses on two groups of local companies; namely, high-growth local companies and other local companies, to examine and compare the influence of utilising governmental initiatives, servicing foreign MNCs and internationalisation on their strategic planning process. The theme of this thesis argues that the approach of an organisation towards strategic planning is not only determined by the internal influences; namely, its firm size and the planning behaviour and attitude of an entrepreneur, as revealed in the literature, but it can also be affected by external influences. The theoretical contribution of this research determines this unique situation in Singapore, and tests the robustness of the conventional models of planning in smaller companies. As a result of the external influences, this study reveals that local companies are more likely to undertake a much more formal strategic planning than the conventional Western literature and models would indicate. High-growth local companies, in comparison, however, had undertaken a more formal and rigorous strategic planning process than other local companies.

Strategic planning in a decentralised industrial group : a process-action study

The research was carried out within a major public company. It sought to implement an approach to strategic planning which accounted for organisational values as well as employing a holistic value-free analysis of the firm and its environment. To this end, an 'ecological' model of the firm was formulated. A series of value-free strategic policies for its development were generated. These policies were validated by the company's top-management.They compared favourably with their own planning outcomes. The approach appeared to be diagnostically strong but lacked sufficient depth in the context of finding realistic corrective measures. However, feedback from the company showed it to be a useful complementary process to conventional procedures, in providing an explicitly different perspective. The research empirically evaluated the company's value-systems and their influence on strategy. It introduced the idea of an organisational 'self-concept' pre-determining the acceptability of various strategies.The values and the "self-concept' of the company were identified and validated, They appeared to have considerable influence on strategy. In addition, tho company's planning process within the decentralised structure was shown to be sub-optimal. This resulted from the variety of value systems maintained by different parts of the organisation. Proposals attempting to redress this situation were ofJered and several accepted. The study was postured as process-action research and the chosen perspective could be succinctly described as a 'worm's-eye view', akin to that of many real planners operating at some distance from the decision-making body. In this way, the normal strategic functionings of the firm and any changes resulting from the researcher's intervention were observed and recorded. Recurrent difficulties of the planning process resulting from the decentralised structure were identified. The overall procedure suggested as a result of the research aimed to increase the viabiIity of planning and the efficiency of the process. It is considered to be flexible enough to be applicable in a broader context.

Public sector investment appraisal:the place of flexibility in the decision making process

This thesis reviews the main methodological developments in public sector investment appraisal and finds growing evidence that appraisal techniques are not fulfilling their earlier promise. It is suggested that an important reason for this failure lies in the inability of these techniques to handle uncertainty except in a highly circumscribed fashion. It is argued that a more fruitful approach is to strive for flexibility. Investment projects should be formulated with a view to making them responsive to a wide range of possible future events, rather than embodying a solution which is optimal for one configuration of circumstances only. The distinction drawn in economics between the short and the long run is used to examine the nature of flexibility. The concept of long run flexibility is applied to the pre-investment range of choice open to the decisionmaker. It is demonstrated that flexibility is reduced at a very early stage of decisionmaking by the conventional system of appraisal which evaluates only a small number of options. The pre-appraisal filtering process is considered further in relation to decisionmaking models. It is argued that for public sector projects the narrowing down of options is best understood in relation to an amended mixed scanning model which places importance on the process by which the 'national interest ' is determined. Short run flexibility deals with operational characteristics, the degree to which particular projects may respond to changing demands when the basic investment is already in place. The tension between flexibility and cost is noted. A short case study on the choice of electricity generating plant is presented. The thesis concludes with a brief examination of the approaches used by successive British governments to public sector investment, particularly in relation to the nationalised industries

Computer simulation for tube-making by the cold roll-forming process

The conventional design of forming rolls depends heavily on the individual skill of roll designers which is based on intuition and knowledge gained from previous work. Roll design is normally a trial an error procedure, however with the progress of computer technology, CAD/CAM systems for the cold roll-forming industry have been developed. Generally, however, these CAD systems can only provide a flower pattern based on the knowledge obtained from previously successful flower patterns. In the production of ERW (Electric Resistance Welded) tube and pipe, the need for a theoretical simulation of the roll-forming process, which can not only predict the occurrence of the edge buckling but also obtain the optimum forming condition, has been recognised. A new simulation system named "CADFORM" has been devised that can carry out the consistent forming simulation for this tube-making process. The CADFORM system applied an elastic-plastic stress-strain analysis and evaluate edge buckling by using a simplified model of the forming process. The results can also be visualised graphically. The calculated longitudinal strain is obtained by considering the deformation of lateral elements and takes into account the reduction in strains due to the fin-pass roll. These calculated strains correspond quite well with the experimental results. Using the calculated strains, the stresses in the strip can be estimated. The addition of the fin-pass roll reduction significantly reduces the longitudinal compressive stress and therefore effectively suppresses edge buckling. If the calculated longitudinal stress is controlled, by altering the forming flower pattern so it does not exceed the buckling stress within the material, then the occurrence of edge buckling can be avoided. CADFORM predicts the occurrence of edge buckling of the strip in tube-making and uses this information to suggest an appropriate flower pattern and forming conditions which will suppress the occurrence of the edge buckling.

Formulation and process engineering of freeze-dried orally disintegrating tablets

Orally disintegrating tablets (ODTs) which are also referred to as orodispersible and fast disintegrating tablets, are solid oral dosage forms which upon placing on the tongue, disperse/disintegrate rapidly before being swallowed as a suspension or solution. ODTs are therefore easier and more convenient to administer than conventional tablets and are particularly beneficial for paediatric and geriatric patients, who generally have difficulty swallowing their medication. The work presented in this thesis involved the formulation and process development of ODTs, prepared using freeze-drying. Gelatin is one of the principal excipients used in the formulation of freeze-dried ODTs. One of the studies presented in this thesis investigated the potential modification of the properties of this excipient, in order to improve the performance of the tablets. As gelatin is derived from animal sources, a number of ethical issues surround its use as an excipient in pharmaceutical preparations. This was one of the motivations, Methocel™ and Kollicoat® IR were evaluated as binders as alternative materials to gelatin. Polyox™ was also evaluated as a binder together with its potential uses as a viscosity increasing and mucoadhesive agent to increase the retention of tablets in the mouth to encourage pre-gastric absorption of active pharmaceutical ingredients (APIs). The in vitro oral retention of freeze-dried ODT formulations was one property which was assessed in a design of experiments – factorial design study, which was carried out to further understand the role that formulation excipients have on the properties of the tablets. Finally, the novel approach of incorporating polymeric nanoparticles in freeze-dried ODTs was investigated, to study if the release profile of APIs could be modified, which could improve their therapeutic effect. The results from these studies demonstrated that the properties of gelatin-based formulations can be modified by adjusting pH and ionic strength. Adjustment of formulation pH has shown to significantly reduce tablet disintegration time. Evaluating Methocel™, in particular low viscosity grades, and Kollicoat® IR as binders has shown that these polymers can form tablets of satisfactory hardness and disintegration time. Investigating Polyox™ as an excipient in freeze-dried ODT formulations revealed that low viscosity grades appear suitable as binders whilst higher viscosity grades could potentially be utilised as viscosity increasing and mucoadhesive agents. The design of experiments – factorial design study revealed the influence of individual excipients in a formulation mix on resultant tablet properties and in vitro oral retention of APIs. Novel methods have been developed, which allows the incorporation of polymeric nanoparticles in situ in freeze-dried ODT formulations, which allows the modification of the release profile of APIs.

Investigation of formulation and process of lyophilised orally disintegrating tablet (ODT) using novel amino acid combination

Lyophilised orally disintegrating tablets (ODTs) have achieved a great success in overcoming dysphagia associated with conventional solid dosage forms. However, the extensive use of saccharides within the formulation limits their use in treatment of chronic illnesses. The current study demonstrates the feasibility of using combination of proline and serine to formulate zero sacharide ODTs and investigates the effect of freezing protocol on sublimation rate and tablets characteristics. The results showed that inclusion of proline and serine improved ODT properties when compared to individual counterparts. Additionally, annealing the ODTs facilitated the sublimation process and shortened the disintegration time. © 2010 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.

Flexible measures in production process:a DEA-based approach

Data envelopment analysis (DEA) has been proven as an excellent data-oriented efficiency analysis method for comparing decision making units (DMUs) with multiple inputs and multiple outputs. In conventional DEA, it is assumed that the status of each measure is clearly known as either input or output. However, in some situations, a performance measure can play input role for some DMUs and output role for others. Cook and Zhu [Eur. J. Oper. Res. 180 (2007) 692–699] referred to these variables as flexible measures. The paper proposes an alternative model in which each flexible measure is treated as either input or output variable to maximize the technical efficiency of the DMU under evaluation. The main focus of this paper is on the impact that the flexible measures has on the definition of the PPS and the assessment of technical efficiency. An example in UK higher education intuitions shows applicability of the proposed approach.

Managing project risk using combined analytic hierarchy process and risk map

The main purpose of the study is to develop an integrated framework for managing project risks by analyzing risk across project, work package and activity levels, and developing responses. Design/methodology/approach: The study first reviews the literature of various contemporary risk management frameworks in order to identify gaps in project risk management knowledge. Then it develops a conceptual risk management framework using combined analytic hierarchy process (AHP) and risk map for managing project risks. The proposed framework has then been applied to a 1500 km oil pipeline construction project in India in order to demonstrate its effectiveness. The concerned project stakeholders were involved through focus group discussions for applying the proposed risk management framework in the project under study. Findings: The combined AHP and risk map approach is very effective to manage project risks across project, work package and activity levels. The risk factors in project level are caused because of external forces such as business environment (e.g. customers, competitors, technological development, politics, socioeconomic environment). The risk factors in work package and activity levels are operational in nature and created due to internal causes such as lack of material and labor productivity, implementation issues, team ineffectiveness, etc. Practical implications: The suggested model can be applied to any complex project and helps manage risk throughout the project life cycle. Originality/value: Both business and operational risks constitute project risks. In one hand, the conventional project risk management frameworks emphasize on managing business risks and often ignore operational risks. On the other hand, the studies that deal with operational risk often do not link them with business risks. However, they need to be addressed in an integrated way as there are a few risks that affect only the specific level. Hence, this study bridges the gaps. © 2010 Elsevier B.V. All rights reserved.

On the stability of conventional and nano-structured carbon-based catalysts in the oxidative dehydrogenation of ethylbenzene under industrially relevant conditions

Relevant carbon-based materials, home-made carbon-silica hybrids, commercial activated carbon, and nanostructured multi-walled carbon nanotubes (MWCNT) were tested in the oxidative dehydrogenation of ethylbenzene (EB). Special attention was given to the reaction conditions, using a relatively concentrated EB feed (10 vol.% EB), and limited excess of O2 (O 2:EB = 0.6) in order to work at full oxygen conversion and consequently avoid O2 in the downstream processing and recycle streams. The temperature was varied between 425 and 475 °C, that is about 150-200 °C lower than that of the commercial steam dehydrogenation process. The stability was evaluated from runs of 60 h time on stream. Under the applied reactions conditions, all the carbon-based materials are apparently stable in the first 15 h time on stream. The effect of the gasification/burning was significantly visible only after this period where most of them fully decomposes. The carbon of the hybrids decomposes completely rendering the silica matrix and the activated carbon bed is fully consumed. Nano structured MWCNT is the most stable; the structure resists the demanding reaction conditions showing an EB conversion of ∼30% (but deactivating) with a steady selectivity of ∼80%. The catalyst stability under the ODH reaction conditions is predicted from the combustion apparent activation energies. © 2014 Elsevier Ltd. All rights reserved.

Global Japanization? The transnational transformation of the labour process

Global Japaniziation? Brings together research from North America, Japan, Europe and Latin America to analyse the influence of Japanese manufacturing investment and Japanese working practices across the global economy. The editors present original case studies of work reorganization and workers' experiences within both Japanese companies and those of their competitors in diverse sectors and national settings. These studies provide a wide-ranging critique of conventional accounts of Japanese models of management and production, and their implications for employees. They offer new evidence and fresh perspectives on the role of "transplants" in disseminating manufacturing innovations, and on the responses of non-Japanese firm in reorganizing production operations and industrial relations.