Examensarbeten för kandidatexamen // Bachelor Theses
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- PostEn jämförande studie av fluiddynamiken för olika fluidiseringsmedium i en kallmodell av en 100 kW-anläggning för kemcyklisk förbränning(2013) ANDERSSON, MIKAELA; FRÄNDBERG, SOFIA; JOHANSSON, DAVID; KARLBRINK, MALIN; ROLEN, ALEXANDRA; Chalmers tekniska högskola / Extern; Chalmers University of Technology / ExternalTo reduce emissions of carbon dioxide (CO2) Carbon Capture and Storage (CCS) technologies have been developed. Chemical Looping Combustion (CLC) is a CO2 capture technology with the CCS framework, and at Chalmers University of Technology in Gothenburg, Sweden, a 100 kW chemical looping combustor has been built. This project aimed to investigate to what degree air can replace helium as the uidizing gas for uid dynamical studies in a CLC cold ow model of the above mentioned 100 kW facility. Experiments were performed using air and helium separately as uidizing gas and pressure data were obtained, which formed the basis for the comparison. The project also aimed to investigate uid dynamics in the uidized bed and study when the risk of slugging occuring was greatest. The results were presented in the form of figures and tables divided into pressure, concentration and standard deviation of the pressure. The results obtained showed that air as uidizing gas did not create the same uid dynamics as helium over the entire fuel reactor. The magnitude of the deviation varied in the various segments of the reactor. Results obtained regarding slugging in the fuel reactor showed that the risk of slugging occuring increased with increasing uidization velocity. The risk was greatest for velocities between 0.7-1.1 m/s. The results also showed that there was a greater risk of slugging occuring when helium was used as uidizing gas.
- PostKonstruktion av anordning för att undersöka förslitning av syrebärarpartiklar för kemcyklisk förbränning(2012) Gunnarsson, Adrian; Gyllén, Patrik; Larsson, Johan; Lindqvist, Simon; Hedström, Joakim; Baban, Ramyar; Chalmers tekniska högskola / Extern; Chalmers University of Technology / ExternalThe purpose of this work is to design and construct a device able to measure the mechanical attrition of oxygen carrier particles. Those particles are used in chemical looping combustion and in the present situation there is a lack of knowledge in how the attrition process work and in which extension. To find already tested solutions trying to answering this problem a literature study wascarried out and the best solution found was the so called Grace-Davison Jet-Cup method. This method is supposed to emulate the attrition caused by a cyclone separator and its advantages are that it is possible to use small test amounts, 5-10 g, and a thirty minutes long test will be enough to acquire useable results. An device was designed based on the Jet-Cup method with some slight modifications. Blueprints for the designed parts were developed and sent to Mekpart AB in M olndal for manufacturing. Remaining components were either ordered from different companies or manufactured by hand. After delivery the device was tested with an amount of 10 g ilmenite and an airow of 15 L/min. The attrition-rate was measured by plotting the weight of fines collected against time.The time-dependence of the particle attrition rate adopted a linear appearance after a short time. When the test was repeated the reproducibility was proven to be good. However the device was not able to be tested for a 20 L/min airow because the pressure drop became higher than calculated and the relief valve mounted in the humidity deviceopened.
- PostKonstruktion av en heliumåtercirkulations-anläggning för en kallmodell av Chemical-looping combustion(2010) Maripuu, Agnes; Broberg, Anna; Lingehed, Emil; Svensson, Malin Kempe; Hamlin, Per; Skargren, Viktor; Chalmers tekniska högskola / Extern; Chalmers University of Technology / ExternalProjektet syftar till att konstruera en återcirkulationsanläggning för helium till en Chemical-Looping Combustion-kallmodell. Företeelser som hanterats är bland annat filtrering, läckage, kompression, tryckutjämning och tryckfall. För att ta fram systemet användes en iterativ metod baserad på beräkningar, undersökningar och expertförfrågningar. Därtill avser projektet att i viss mån undersöka hur höga bäddhöjder påverkar den aktuella kallmodellen. Undersökningarna utgår från tryck- och hastighetsmätningar. Projektet resulterade i ett välfungerande återcirkulationssystem för helium. De ekonomiska beräkningar som utförts för att utvärdera systemets effekt visar att ca 26 timmars kontinuerlig drift krävs för att finansiera systemet vid ett flöde på 70 Nm3/h helium, jämfört med fallet då helium inte återcirkuleras. Vid driftstopp sker ett uppskattat läckage på 0,084 m3/dygn. Mätdata för höga bäddhöjder presenteras med avseende på tryck, terminalhastighet, sandvikt och partikelflöde.