Coal is today the fossil fuel which offers the greatest proven reserves. Due to increasingly stringent environmental legislation, coal fired combustion systems should be based on clean coal combustion technologies. For clean and efficient energy generation from coal reserves, the most suitable technology known to date is the &lsquo / Fluidized Bed Combustion&rsquo / technology. Applications of circulating fluidized bed combustion (CFB) technology have been steadily increasing in both capacity and number over the past decade for the utilization of this resource. Designs of these units have been based on the combustion tests carried out in pilot scale facilities to determine the combustion and desulfurization characteristics of the coals and limestones in CFB conditions. However, utilization of Turkish lignites with high ash, volatile matter and sulfur contents in CFB boilers necessitates adaptation of CFB combustion technology to these resources. Therefore, it has been the objective of this study to investigate combustion characteristics of an indigenous lignite in a circulating fluidized bed combustor. In this study, a 150 kWt Circulating Fluidized Bed (CFB) Combustor Test Unit was designed and constructed in Chemical Engineering Department of Middle East Technical University, based on the extensive experience acquired at the existing 0.3 MWt Bubbling Atmospheric Fluidized Bed Combustor (AFBC) Test Rig. Following the commissioning tests, combustion tests were carried out for investigation of combustion characteristics of &Ccedil / an lignite in CFB conditions and for comparison of the design of the test unit with experimental findings. The steady state results of the combustion tests reveal that &Ccedil / an lignite is fired with high combustion efficiency. Temperature profile along the riser is achieved to be almost uniform by good control of cooling system. Pressure drop through the dilute zone is found to be negligible because of low solid hold up in this zone. CO and NO concentrations within the flue gas are fairly lower, whereas N2O concentration is higher compared to the ones obtained in the bubbling AFBC test rig firing the same lignite. The deviation of particle size distributions of bottom ash and circulating ash among the tests are in line with the deviation of superficial velocity. In order to assess the validity and predictive accuracy of the pressure balance model, it was reapplied to the test unit utilyzing the revised input data based on the results of the combustion tests. Comparison of the model predictions with experimental results revealed that the predictions have acceptable agreement with the measurements. In conclusion, the performance of 150 kW CFBC Test Unit was found to be satisfactory to be utilized for the long term research studies on combustion and desulfurization characteristics of indigenous lignite reserves in circulating fluidized bed combustors.

This thesis project made in collaboration with Stegia AB focuses on the development of an automated testing unit for control units in wood stoves. The reason behind this work is new laws regarding safety and performance for controlsystems in household appliances and an ambition to digitize the traditional woodstove. The current control units which are essential for managing functions andmonitoring different states in the stove also allow users to receive operational information via a mobile app. Throughout the testing it’s required to ensure that the produced control units perform as functionally desired. To meet these requirements each unit needs to undergo comprehensive functio-nal tests after assembly to guarantee flawless operation and the ability to handle the tasks they where designed for. This work aims to develop a test unit that can automate this process, improving both production reliability and efficiency. The project focuses on constructing a prototype that uses both hardware and software to perform automated tests that simulate various scenarios and loads that the control units might encounter. By examining how test automation should be carried out and exploring techniques such as Hardware in the Loop (HIL), it is possible to create environments similar to those in which the units will be used. This ensures that each component functions as it should during actual use in the stove. The conclusion of this work is that an automated testing unit is technically feasible and a prototype has been developed. With further development there is potential to standardize the testing process and leading to higher product quality and greater customer satisfaction. / Detta examensarbete som genomförts i samarbete med Stegia AB inriktar sig på utvecklingen av en automatiserad testenhet för styrenheter i braskaminer. Orsaken till att detta arbete genomförts grundar sig i nya lagar gällande säkerhet och prestanda för styrsystem i hushållsapparater samt en ambition att digitalisera den traditionella braskaminen. De nuvarande styrenheterna vilka är avgörandeför att hantera funktioner och övervaka olika tillstånd i braskaminen möjliggör även att användaren får driftsinformation i en mobil-app. För att göra detta möjligt krävs noggrann testning för att säkerställa att de styrenheter som produceras presterar enligt vad som funktionsmässigt önskas. För att möta dessa krav önskas att varje enhet skall kunna genomgå omfattande funktionstester efter montering för att garantera att de fungerar felfritt och kan hantera de uppgifter som de är designade för. Detta arbete syftar till att utveckla en testenhet som kan automatisera denna process vilket inte bara förbättrar tillförlitligheten i produktionen utan även effektiviserar hela produktionsprocessen. Projektet fokuserar på att konstruera en prototyp som använder både hårdvara och mjukvara för att utföra automatiserade tester som simulerar olika scenarion och belastningar som styrenheterna kan utsättas för. Genom att undersöka hur testautomatiersing bör utföras samt undersöka tekniker som Hardware inthe Loop (HIL) möjliggörs att skapa miljöer likt de som enheterna kommer att användas i. Detta i sin tur säkerställer att varje komponent fungerar som den ska under vid använding i braskaminen. Slutsatsen av detta arbete är att en automatiserad testenhet är tekniskt genomförbar och att en prototyp tagits fram. Med ytterligare utveckling finns potential att standardisera testprocessen vilket kan leda till högre produktkvalitet och större kundnöjdhet.

This master thesis aims to develop a test methodology for electromechanical linear actuators. A linear actuator acts as a linear motor, converting a power source to linear motion. The electromechanical linear actuator in this project has an electric motor as its power source and uses a rack and pinion system to transfer that power to linear motion.  The test methodology is to impose a force onto the rack of the actuator, to ensure that operation under a load scenario is within specification. To accomplish this, the design of a test rig implementation is analyzed. The test rig consists of the test unit, which is to be tested, the load unit, which is to provide the load force, and a control system for the load unit. The load unit is another linear actuator and is controlled via a load cell. The load cell gives out the load force being applied, and the controller gives out the corresponding appropriate motor command to the load unit to ensure the load force is as desired. This analysis is done through simulation of the setup. Viable options for the setup were first analyzed in order to implement the deemed promising options for a setup into a simulation environment. The simulation environment in this project was Simscape, an extension of MATLAB’s Simulink. In simulation the parameters for the test rig were rigorously analyzed, in order to determine acceptable thresholds. The primary load unit tested was another electromechanical linear actuator from Cascade Drives, the model A-100-8P. Two secondary setups, one using the same model as being tested, and another setup using two of the models being tested. Simulation found that the suggested options’ applied load force have a poor rise time, large overshoot and substantial oscillation errors. The primary source for this was determined to be the latency between load cell input, and motor command output in the controller. The poor metrics from the result could lead to problems when emergency braking, and with a long honing period, which would render most test data unusable.