Due to industrial development and population growth Türkiye 's energy demand is increasing every year. Although renewable energy sources are becoming widespread these sources are not sufficient enough to meet all of the energy demand of Turkey in the near future. Therefore fossil fuels are going to be used for a long time for domestic heating and electricity production. The disadvantage of using fossil fuels is sulfur dioxide (SO 2) emissions during the combustion according to the sulfur content of the fuel. Turkey's energy consumption depends heavily on fossil fuels. Therefore SO2 emission level is going to be higher than the legal limits according to Industrial Based air Pollution Control Regulation (22 JULY 2006) since our lignite has a low calorific heating valve and high sulfur content which are 1807 kcal/kg and 1.85 % respectively. Although there are disadvantages of using lignite for electricity production it's our native energy source and by applying appropriate desulphurization methods it is possible to reduce emission of SO2 to lower levels. Removal of SO2 is not only legal obligation but also an act for protection of the public health and environment. Because an important effect of S02 is it's contribution to acid rain. Acid aerosols cause chlorosis, the loss of chlorophyll and plasmolysis, tissue collapse of leaf cells in plants. And cause bronchoconstriction, above 1 ppm in air and throat; eye and nose irritation above 10 ppm concentration, on human beings.In this study, most prevalent way to prevent SO2 emission, desulphurization flue gas after combustion of fossil fuel especially lignite, is elaborated. In pre-combustion processes coal is crushed, grinded in coarse particles and treated with water by flotation in lavers. But this physical treatment decrease the piritic sulfur in coal and can not remove the organic bonded sulfur. Overall decrease in sulfur content is 10-40% in this operation. In desulfurization during combustion dry sorbent is added to the combustion chamber or sorbent is pressed with the fine coal powder during briquetting operation. The disadvantage of this process is sintering of sorbent material such as limestone, lime or soda at higher temperatures up to 800-1000 °C.Technical and economical evaluation of desulphurization methods is given. Conventional wet scrubbing, spray dry and dry sorbent injection methods are investigated. Types of sorbents used in desulphurization processes such as magnesium, calcium, sodium, potassium based and ammonia sorbents are illustrated and reactions of them with SO2 is given. In order to determine the most economical method capital investment of three different desulphurization processes (wet, spray dry and dry injection) is calculated by using Gutrie's "equipment module cost technique". In calculation of capital investment of those three major desulphurization methods these steps are followed; preparation of detailed process sheet, material balances, list of equipment and list of utility consumption. This technique depends on multiplying the bare module cost of equipment at base conditions by the factors relating to pressure, material and equipment type. Base case in this study is carbon steel material and operations near ambient pressure. By using the base case, that is 100 MW thermal power station using heating value of 2000 kcal/kg, 2% sulfur content coal and using 40% excess air for dry injection method and 210 MW for wet method, computer programme is produced for calculating the total capital investment and total annual cost. An algorithm for computer program is prepared to calculate the capital investment and total annual cost for desulphurization methods which are investigated. Finally a computer program is written to determine the lowest capital investment among those three methods of desulphurization is found as dry sorbent injection. The disadvantage of this method is the limitation of SO2 removal. Maximum SO2 removal efficiency is 75%> for limestone and 85% when lime is used. In order to overcome this problem using more active sorbent, evaluation of Beypazarı trona is investigated(90 % desulfurization rate for dry injection). Although it is more active than calcium based sorbents, it is much more expensive in the market. But if obtained by solution mining from Beypazarı it is going to be cheaper than both lime-stone and lime. Capital investment cost model for certain methods are developed as a function of plant capacity and sulfur content for certainsorbents.As an example for dry sorbent injection method in the case of trona, as a sorbent, capital cost model is as follows;