| title: | Behaviour of Mineral Matter and Thermal Effects by Burning of Oil Shale Fuel in FBC |
|---|---|
| reg no: | ETF6661 |
| project type: | Estonian Science Foundation research grant |
| subject: |
2.5. Power Engineering |
| status: | accepted |
| institution: | TTU Faculty of Mechanical Engineering |
| head of project: | Arvo Ots |
| duration: | 01.01.2006 - 31.12.2009 |
| description: | The project deals with combustion of oil shale in fluidized - bed (FB) boilers and belongs to the field of top technology. Nowadays fluidized bed combustion (FBC) is replacing the pulverized firing (PF) technology. Replacing high - temperature PF with low-temperature FBC causes noticeable differences in behavior of oil shale mineral matter and in concurrent thermal effects that in turn influence the efficiency of thermal processes in boiler and fuel rate. Thermal efficiency of boiler and power unit is determined basing on the amount of heat released at burning a fuel sample in calorimetric bomb and heating value calculated on this basis . To the combustion heat of fuel organic matter in calorimetric bomb thermal effects of transformations in fuel mineral matter are to be added. Thermal effects from fuel mineral matter depend on the composition and content of mineral matter and on the extent of transformation processes. While burning oil shale, thermal effects of mineral matter are mainly caused by decomposition of carbonate minerals, by sulfation of ash components and by formation of secondary minerals. The influence of these thermal effects in the case of oil shale are characterized by a relationship between thermal effects of carbon dioxide, sulfating sulfur and secondary minerals in mineral part. The numerical values of this ratio by mass are – 1:0.12:0.45:0.04. If the amount of heat released at burning fuel (oil shale) organic part in calorimetric bomb and in boiler are equal, thermal effects caused by transformations in mineral matter are noticeably different. This is caused by differences in temperature level and composition of the surrounding environment , so depending on combustion technology. The influence of processes going on in minerals is especially important in the case of oil shale FBC, owing to lower extent of decomposition of carbonate minerals and higher extent of sulfation of ash components. According to theoretical calculations, thermal effect caused by minerals of mineral part can be up to 6 – 8% of the total heat released in oil shale FB boiler. Summarizing above given the objectives of the project are: 1. Investigation of combustion process in calorimetric bomb and determination of separate thermal effects , studying the transformations in oil shale mineral matter in wide range of oil shale composition. Elaboration of analytical formulas for calculation of single and total thermal effects depending on oil shale composition. Determination of conventional heating value and its dependence on oil shale composition. The results will base on chemical-mineralogical analysis of oil shale samples and combustion residue from calorimetric bomb. 2. Determination of the amount of heat released in oil shale FB boiler, basing on the conventional heating value and on transformation processes of mineral matter in boiler. Elaboration of an analytical formula for determination of the amount of heat released in boiler burning oil shale depending on conventional heating value, on oil shale composition and on parameters characterizing combustion process. 3. Creation of the basis for determination of the efficiency of FBC boiler and power unit , boiler`s thermal losses and fuel rate. The results can be applied also for calculating carbon dioxide emissions. The results of investigation are directly applicable in analysis of exploitation data of power units equipped with FB boilers and in determination of thermal efficiency data. The results are also applicable in designing of new FB boilers and power units. |
| project group | ||||
|---|---|---|---|---|
| no | name | institution | position | |
| 1. | Arvo Ots | Tallinna Tehnikaülikooli Mehaanikateaduskond | ||
| 2. | Tõnu Pihu | |||