99/04024 Suggestions for the refurbishment of a Greek lignite-fired power plant. Efficiency, costs, and operation aspects: Stamatelopoulos, G. N. et al. FACT (Am. Soc. Mech. Eng.), 1998, 22, (1), 185–191

Abstract

The present paper outlines measures for the refurbishment of the Greek lignite-fired power plant Kardia and discusses their impact on the efficiency, the electricity generation costs and the operation of the plant. The power plants Kardia III and IV with an installed capacity of 300 NW{sub el} each were constructed in the late 70's in Northern Greece and still operate as base load units for the Public Power Corporation (PPC) of Greece. Several problems are detected during the operation of these two units concerning high flue gas outlet temperature--and consequently low boiler efficiency, poor electrostatic precipitator performance, high slagging tendency, fluctuating temperature field resulting unstable steam temperatures and a high percentage of leakage air. To improve the current situation PPC in collaboration with the National Technical University of Athens (NTUA) conducted a feasibility study to set the priorities and to select the most suitable measures for the refurbishment of these two units. Taking advantage of the international experience, the possible measures applicable in the case of brown coal fired units upgrade were collected, categorized and presented to PPC's management. The proposed measures were evaluated for the specific case of Kardia and then it was decided to further examine the followingmore » actions: Sealing of the boiler in order to minimize the amount of the leakage air, extension of the economizer followed by the replacement of one bled steam feed water preheater aiming at the decrease of the flue gas outlet temperature and optimization of the soot blowers operation. For these actions and using the process simulation program ENBIPRO, the expected benefits in terms of efficiency as well as the dimensions of the necessary additional heating surface and the influence of the rearrangement of the heating surfaces in the boiler on the water/steam cycle were calculated. The costs of the suggested actions were estimated together with the time frame for their implementation. Investment plans were put together and the pay back time for each alternative was evaluated. Based on the discussed feasibility study PPC initialized a closer collaboration with a steam generator construction company in order to include the refurbishment of Kardia III and IV to its investment planning program for the coming years.« less