yes / This work describes how the design and operation parameters of the Multi-Stage Flash (MSF) desalination process are optimised when the process is subject to variation in seawater temperature, fouling and freshwater demand throughout the day. A simple polynomial based dynamic seawater temperature and variable freshwater demand correlations are developed based on actual data which are incorporated in the MSF mathematical model using gPROMS models builder 3.0.3. In addition, a fouling model based on stage temperature is considered. The fouling and the effect of noncondensable gases are incorporated into the calculation of overall heat transfer co-efficient for condensers. Finally, an optimisation problem is developed where the total daily operating cost of the MSF process is minimised by optimising the design (no of stages) and the operating (seawater rejected flowrate and brine recycle flowrate) parameters.

[pt] Nesta tese é apresentada uma metodologia de seleção de modelos em experimentos mistura-processo e reunidas as técnicas estatísticas necessárias ao planejamento e análise de experimentos com mistura com ou sem variáveis de processo. Na pesquisa de seleção de modelos foi utilizado um experimento para determinar as proporções ótimas de um misto químico do mecanismo de retardo para ignição de um motor foguete. O misto químico consiste de uma mistura de três componentes. Além das proporções dos componentes da mistura, são consideradas duas variáveis de processo. O objetivo do estudo é investigar as proporções dos componentes da mistura e os níveis das variáveis de processo que colocam o valor esperado do tempo de retardo (resposta) o mais próximo possível do valor alvo e, ao mesmo tempo, minimizam o tamanho do intervalo de previsão de uma futura resposta. Foi ajustado um modelo de regressão linear com respostas normais. Com o modelo desenvolvido foram determinadas as proporções ótimas dos componentes da mistura e os níveis ótimos das variáveis de processo. Para a seleção do modelo foi utilizada uma metodologia de duas etapas, que provou ser eficiente no caso estudado. / [en] This thesis presents a methodology for model selection in mixture-process experiments and puts together the statistical techniques for the design and analysis of mixture experiments with or without process variables. An experiment of a three-component mixture of a delay mechanism to start a rocket engine was used in the research. Besides the mix components proportions, two process variables are considered. The aim of the study is to investigate the proportions of the mix components and the levels of the process variables that set the expected delay time (response) as close as possible to the target value and, at the same time, minimize the width of the prediction interval for the response. A linear regression model with normal responses was fitted. Through the developed model, the optimal proportions of the mix components and the levels of the process variables were determined. A two-stage methodology was used to select the model. This methodology for model selection proved to be efficient in the studied case.

El fin de este proyecto de tesis fue Sintonizar un controlador PID, por los métodos de Ganancia Límite y Tanteo, para controlar de manera remota la variable Nivel en un módulo educativo del Laboratorio de control de la Universidad Ricardo Palma, esto se hizo con la finalidad que el alumno pueda entender la sintonía de un PID, lo cual es siempre recurrente en el campo. El control remoto permitió asemejar mucho a los procesos actuales. Al finalizar la tesis se obtuvo un control PID sintonizado bajo el método de Ganancia Límite con valores de Kp=0.6, Ti=0.067 minutos y Td=0.017 minutos; el cual dio valores de Error de estado estacionario=3.41% o 0.341, Tiempo de estabilización=30 segundos, Máximo sobre impulso=5.505% y Tiempo de subida=26 segundos; para un Set Point de 10 cm. Por otro lado, para un Set Point de 30 cm, dio valores de Error de estado estacionario=3.03% o 0.91, Tiempo de estabilización=67 segundos, Máximo sobre impulso=0.381% y Tiempo de subida=66 segundos. Además, se sintonizó bajo el método de Tanteo con valores de Kp=0.3, Ti=0.019 minutos y Td=0.01 minutos; el cual dio valores de Error de estado estacionario=2.99% o 0.299, Tiempo de estabilización=40 segundos, Máximo sobre impulso=6.69% y Tiempo de subida=39 segundos; para un Set Point de 10 cm. Por otro lado, para un Set Point de 30 cm, dio valores de Error de estado estacionario=1.87% o 0.56, Tiempo de estabilización=75 segundos, Máximo sobre impulso=0.398% y Tiempo de subida=73 segundos. The purpose of this thesis project was Tuning a PID controller, using methods of grope and Gain Limit to remotely control the variable level in an educational module Control Laboratory of the University Ricardo Palma, this was done in order that students can understand the tuning of a PID, which is always recurring in the field. The remote control allowed much resembles the current processes. After the thesis tuned PID control method gain under the limit values of Kp = 0.6 was obtained, Ti = Td = 0067 minutes and 0017 minutes; which gave values of steady state error = 3.41% or 0.341, Settling time = 30 seconds Maximum overshoot = 5.505% and Rise Time = 26 seconds; Set for a Point of 10 cm. On the other hand, for a set point of 30 cm, gave values of steady state error = 3.03% or 0.91 Settling time = 67 seconds Maximum overshoot = 0.381% and Rise Time = 66 seconds. Furthermore, it was tuned under trial and error with values of Kp = 0.3, Ti = Td = 0019 minutes and 0.01 minutes; which gave values of steady state error = 2.99% or 0.299, Settling time = 40 seconds Maximum = 6.69% overshoot and rise time = 39 seconds; Set for a Point of 10 cm. On the other hand, for a set point of 30 cm, gave values of steady state error = 1.87% or 0.56 Settling time = 75 seconds Maximum overshoot = 0.398% and Rise Time = 73 seconds.

Controlled Auto Ignition (CAI) combustion is a new combustion principle in internal combustion engines which has in recent years attracted increased attention. In CAI combustion, which combines features of spark ignition (SI) and compression ignition (CI) principles, air/fuel mixture is premixed, as in SI combustion and auto-ignited by piston compression as in CI combustion. Ignition is provided in multiple points, and thus the charge gives a simultaneous energy release. This results in uniform and simultaneous auto-ignition and chemical reaction throughout the whole charge without flame propagation. CAI combustion is controlled by the chemical kinetics of air/fuel mixture with no influence of turbulence. The CAI engine offers benefits in comparison to spark ignited and compression ignited engines in higher efficiency due to elimination of throttling losses at part and idle loads. There is a possibility to use high compression ratios since it is not knock limited, and in significant lower NOx emission (≈90%) and particle matter emission (≈50%), due to much lower combustion temperature and elimination of fuel rich zones. However, there are several disadvantages of the CAI engine that limits its practical application, such as high level of hydrocarbon and carbon monoxide emissions, high peak pressures, high rates of heat release, reduced power per displacement and difficulties in starting and controlling the engine. Controlling the operation over a wide range of loads and speeds is probably the major difficulty facing CAI engines. Controlling is actually two-components as it consists of auto-ignition phasing and controlling the rates of heat release. As CAI combustion is controlled by chemical kinetics of air/fuel mixture, the auto-ignition timing and heat release rate are determined by the charge properties such as temperature, composition and pressure. Therefore, changes in engine operational parameters or in types of fuel, results in changing of the charge properties. Hence, the auto-ignition timing and the rate of heat release. The Thesis investigates a controlled auto-ignition (CAI) combustion in internal combustion engines suitable for transport applications. The CAI engine environment is simulated by using a single-zone, homogeneous reactor model with a time variable volume according to the slider-crank relationship. The model uses detailed chemical kinetics and distributed heat transfer losses according to Woschini's correlation [1]. The fundamentals of chemical kinetics, and their relationship with combustion related problems are presented. The phenomenology and principles of auto-ignition process itself and its characteristics in CAI combustion are explained. The simulation model for representing CAI engine environment is established and calibrated with respect to the experimental data. The influences of fuel composition on the auto-ignition timing and the rate of heat release in a CAI engine are investigated. The effects of engine parameters on CAI combustion in different engine concepts fuelled with various fuels are analysed. The effects of internal gas recirculation (IEGR) in controlling the auto-ignition timing and the heat release rate in a CAI engine fuelled with different fuels are investigated. The effects of variable valve timings strategy on gas exchange process in CAI engine fuelled with commercial gasoline (95RON) are analysed.

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