The MixAlco process uses an anaerobic, mixed-culture fermentation to convert lignocellulosic biomass to carboxylate salts. The fermentation broth must be clarified so that only carboxylate salts, water, and minimal impurities remain. Carboxylate salts are concentrated by evaporation and thermally decomposed into ketones. The ketones can then be chemically converted to a wide variety of chemicals and fuels. The presence of excess lime in the thermal decomposition step reduced product yield. Mixtures of calcium carboxylate salts were thermally decomposed at 450 degrees C. Low lime-to-salt ratios (g Ca(OH)2/g salt) of 0.00134 and less had a negligible effect on ketone yield. In contrast, salts with higher lime-to-salt ratios of 0.00461, 0.0190, and 0.272 showed 3.5, 4.6, and 9.4% loss in ketone yield, respectively. These losses were caused primarily by increases in tars and heavy oils; however, a three-fold increase in hydrocarbon production occurred as well. To predict ketone product distribution, a random-pairing and a Gibbs free energy minimization model were applied to thermal decompositions of mixed calcium and sodium carboxylate salts. Random pairing appears to better predict ketone product composition. For sodium and calcium acetate, two types of mixed sodium carboxylate salts, and two types of mixed calcium carboxylate salts, activation energy (EA) was determined using three isoconversional methods. For each salt type, EA varied significantly with conversion. The average EA for sodium and calcium acetate was 226.65 and 556.75 kJ/mol, respectively. The average EA for the two mixed sodium carboxylate salts were 195.61, and 218.18 kJ/mol. The average EA for the two mixed calcium carboxylate salts were 232.78, and 176.55 kJ/mol. In addition, three functions of conversion were employed to see which one best modeled the experimental data. The Sestak-Berggren model was the best overall. Possible reactor designs and configurations that address the challenges associated with the continuous thermal decomposition of carboxylate salts are also presented and discussed. Methods of fermentation broth clarification were tested. Flocculation showed little improvement in broth purity. Coagulation yielded broth of 93.23% purity. Filtration using pore sizes from 1 micrometer to 240 Daltons increased broth purity (90.79 to 98.33%) with decreasing pore size.

Surface temperature and heat flux measurements were made in a single cylinder SI engine piston when uncoated and with two different surface coatings: a metal TBC and YSZ. A new thermocouple was developed to accurately measure surface temperatures. The engine was operated in a standard full load mode and a knock promoting mode featuring heated intake air and advanced spark timing. Cylinder pressures were measured to quantify knock. It was found that average heat flux into the piston substrate was 33 % higher with the metal TBC and unchanged with the YSZ relative to the uncoated surface. The increase with the metal TBC was attributed to its surface roughness. However, the metal TBC and YSZ reduced peak heat flux by 69 and 77 %, respectively. Both the metal TBC and YSZ reduced knock compared to the uncoated surface. After testing, the metal TBC was undamaged and the YSZ was slightly chipped.

When trace quantities of an alkali element are added to a flame, its optical and electrical properties change significantly. Addition of alkali seed to both premixed and diffusion flames has been used in the development of two new techniques, one for flame temperature measurement and the other for enhanced mixing. Advantage has been taken of the spectral characteristics of alkali seeds in the development of a non-invasive optical flame temperature measurement technique. The strongest resonance line of alkalis is in fact a doublet, and the two peaks can be subjected to different optical treatment. A cesium-seeded flame was exposed to radiation which was selectively filtered to yield different apparent source temperatures at the wavelengths corresponding to the doublet resonance lines. The ratio of the emission peak heights at the two wavelengths relates directly to flame temperature. This technique allows real-time measurement of flame temperatures up to 2800 K. A second process has been investigated which takes advantage of the enhanced electrical conductivity of alkali-seeded diffusion flames. The study first required a characterization of electrical discharges through planar diffusion flames. Because of the increase in conductivity, alkali-seeded diffusion flames can carry current when a transverse electric potential is applied. The behavior of diffusion flames carrying electrical current has been investigated. The dependence on electrode position and gap is reported and the behavior is contrasted with that described in the literature for premixed flames. A planar diffusion flame was subjected to a steady magnetic field parallel to the flow direction while an orthogonal, oscillating current passed through the flame sheet. A Lorentz body force was induced on the flame sheet which acted to move it alternately toward the fuel and oxidizer streams, improving bulk mixing in the flame. High-speed video images of the oscillating flame were analyzed to obtain its maximum lateral velocity. The results compared well with predictions from a simple theoretical model. / Graduation date: 1992

No description available.

No description available.

No description available.

This is a report written for an examination project C-level, on the subject of energy. The examination project is a product of the FVB Sweden AB (district heating bureau). It started with a meeting with Stefan Jonsson FVB Sweden AB, were he explained the content of the project, and from this a presentation of the problem was made. The problem that needed to be solved was how they could control the valves in the system to provide heating to everyone in the system. The valves are often oversized so the pump in the heating plant would have to be enormous to be able to provide enough flow to be sufficient, if everyone in the system had there valves fully opened.   I came up with two solutions to the problem, one was a wireless network that could keep track of the valves and the other solution was an extra sensor that was placed on the radiator. The purpose for that was to open the valve if the temperature dropped more than one degree inside. With the help of a program called IDA it was calculated that, if the temperature drop five degrees, they would have sixteen hours at the heating power plant to open the flow before the sensor open the valves.   After careful consideration I came up with the conclusion that the wireless network must be the best solution. Mostly because you can monitor all the clients in the system from the heating power plant and that will make it easier to discover faults and temperature differences. Wireless networks is already a well tested solution in form of wireless controlled electricity meters so it shouldn’t be to much of a problem connecting these sensors to it either.

This project has been developed at the company Gavlegardarna. The companyowns a large part of the buildings of Gävle and two of them are the objective ofthe project. Gavlegardana is highly concerned about the environment; for thisreason, they cooperate on the subject with the energy management from theirtechnical department. Gävle is one of the Swedish cities where the DH (district heating) network isdistributed, arriving to most of the dwellings, industries and commercialbuildings. As DH uses environmentally friendly sources of energy,Gavlegardana is introducing it in its buildings. Electrical radiators and boilers were installed in the buildings when the price ofelectricity was more affordable than nowadays. The price of the electricity canbe considered 1,23 SEK/kWh while the DH price is 0,45 SEK/kWh. Consequently, this is another reason why the objective of the company at thepresent time is to replace electrical space heating systems by means of districtheating. The energy balance of the buildings is analysed in order to study their currentenergy situation. This entails the consideration of heat gains and lossesinvolved. The heat gains of the building are the heat from solar radiation whicharrives at the building trough the windows, the heat internally generated (bypersons, lighting and other devices) and the heat supplied. The heat losses are composed by the transmission trough walls and windows, the infiltrations, the heat used for hot tap water and the ventilation losses. An important part of the work required to calculate the energy balance hasconsisted of the collection and organization of all the data (areas, types ofmaterial, electrical devices, lighting, number of employees, opening hours...).This data comes from the drawings of the buildings provided by the companyand from the information gathered during the visits to the installation. In addition, the ventilation flows were measured in-situ using the tools provided by Theorells. Gavle Energi, the DH distributor company, has been contacted in order to fixthe cost and other details related to the district heating connection. The heatexchanger models, selected from Palmat System AB, are TP20 for Building Aand TP10 for Building B. TP20 provides 100 kW of heating and 0,4 l/s of hot tap water and TP10 provides 50 kW and 0,31 l/s respectively. The capital cost is 187500 SEK which includes the heat exchangers and the connection cost. As the secondary circuit is not currently installed because the existing system iscomposed by electrical radiators, the installation of the piping network in thebuilding has been designed. The radiators’ power is calculated taking intoaccount the need of heat in each room which is estimated as the transmissionlosses. This need of heat calculated is higher than the energy currently supplied which means that the thermal comfort is not achieved in all the rooms of the buildings. In spite of using more energy for space heating, the change of heat sourceentails a lower energy cost per year. The selected radiators are from Epeconand the investment cost (including the installation) is 203671 SEK. The brand of the selected pipes is Broson and the investment cost of the total piping system is 66000 SEK. The initial investment of the new installation is 457171 SEK, considering the DHconnection, heat exchangers, radiators and pipes. If the initial investment istotally paid in cash by the company the payback will be fulfilled in 6 years. Incase of borrowing the money from the bank (considering an interest rate of 5%), two possibilities can be considered: paying back the money in annual rates over 15 years or 30 years of maturity. The paybacks are 11 and 8 years respectively. After designing the DH piping system in the buildings, estimating the total costs of the investment and studying the project’s feasibility by suggesting different payment options, some possible energy savings are recommended.   The first of the options refers to the transmission losses trough the windowswhose values’ are considerably high. Using a glass with a lower U-value, theselosses can decrease until 66% (with triple glass windows). Consequently, thepower required for space heating can also be reduced until 26%. Regarding the ventilation, rotating heat exchangers are currently used, whichentails the problem of smells mixture detected by the users of the buildings. By changing them with flat-plate heat exchangers, the problem is solved and the efficiency is increased from 66% to 85%. The new heat exchanger cost is340387 SEK and it has a payback of 10 years.

Detta arbete beskriver hur Herons ångkula fungerar och hur den har byggts. Ånkulan konstruerades för ca 2000 år av Heron. Meningen var att få fram en verkningsgrad eftersom denna var okänd. Verkningsgraden blev aldrig konstaterad. Endast en teoretisk beräkning för verkningsgraden gjordes. Kulan sattes inte i rotation av ångtrycket som byggdes upp när det eldades under denna. Anledningen var troligen att det var för mycket friktion i tätningen som skulle tillföra matarvatten in i kulan. Värmeöverföringen mellan gaslågan och kulkroppen var inte heller den mest optimala. Kulan med tillhörande kringutrustning byggdes under dec-07/jan-08 efter eget tycke och utan någon existerande ritning. Den byggdes för att efterlikna originalet så mycket som möjligt. Dessutom hade en mindre ångkula byggts några år tidigare och denna hade visat sig fungera. Denna något större ångkula fick därför samma utseende. Eftersom ångkulan inte orkade rotera råder det inga tvivel om hur ineffektiv denna tidiga reaktionsmotorn är. Den fick ingen praktisk betydelse för 2000 år sedan, och det har den inte idag heller. En framräknad verkningsgrad finns redovisad och denna blev mycket låg. Det var stimulerandel att bygga Herons ångkula men konstruktionen i sig tillhör inte de mest lyckade. / This work describes how the Herons steam ball was built and how it works. It was constructed by Heron 2000 years ago. The purpose was to determine the efficiency of the steam ball because it was unknown. The efficiency was never determined. It was only theoretically determined by calculations. The steam pressure never gave the steam ball rotation when heat was added underneath the construction. A possible reason was that friction in the sealing for supplying feed water into the steam ball was too high. The heat transfer was also a reason that the construction did not rotate. The steam ball and necessary equipment was fabricated in dec-07/jan-08. It was built without any drawings. The goal was to make it look like the original as much as possible. A smaller steam ball was built some years before. This one did rotate and therefore was the same design given to the bigger one. Because of the lack of rotation there was no doubt if the steam ball was a sucsess or not. It was not used for any real purpose 2000 years ago and this has not changed. A calculated figure of the efficiency was documented in this rapport, and it was very low. It was amusing to design and build the steam ball but the construction was clearly no success.

The Veo+ projector is using a cooling system that consists of fan and blowers. This system is cooling the electronic components of the device and the lamp of the projector, however extracting a high noise. To lower this noise the rpm speeds (rotational speed) of the fan and blowers should be decreased. Thus, lowering the speed will result in higher temperature values in whole system (inside the device). While lowering the speed, the higher temperature values should be kept within the thermal design specifications of the electronic components. The purpose of this thesis work is to find an optimal solution with lower rpm speeds of the fan and blowers while keeping the temperatures of the various components of the device (touch temperature of the enclosure and electronic components) within the temperature design limits. Before testing the device to find the optimum state, the design limits of the device are determined. Then, by using the design of experiment methods like Taguchi, the optimum state for the device within the design specifications is obtained. Finally, additional tests are applied within the optimum state to demonstrate a fan algorithm as a final solution. While doing the experiments thermocouples are used for measuring the component temperatures.