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.

The water and coal samples from the Manisa-Soma-DeniS region were studied on the basis of their basic characteristics, inorganic and organic parameters. Coal samples were determined as low-quality lignite. They have high concentrations of arsenic, uranium and lead. The organics in the coal samples are of aliphatic hydrocarbons and their derivatives (alkanes and alcohols), methyls, phthalates, naphtalenes and benzenes. They are inactive and low in concentrations. Water samples have basic characteristics within the range of drinking waters. They also have high arsenic and uranium concentrations indicating a possible leaching. Their organic compounds are similar to those in the coal samples. However, these organic compounds are not as toxic as those found in endemic samples and their concentration is also very low. Therefore, they are considered not to be a potential for Balkan Endemic Nephropathy (BEN)-disease. On the basis of the findings of this study, the area can be concluded as non-endemic region.