Zhodnocení parametrů parního kotle po komplexní obnově

Abstract

Dissertation thesis is focused on problems of components of flue gas and boiler efficiency after the complex reconstruction of the power station Tušimice II, first stage. The base of reconstruction is to meet contractual values, i.e. the reduction of emission limits and to achieve higher efficiency.With respect to the current trends in power engineering, and not just in the CR, but also throughout the EU, with reconstruction of power station Tušimice II, designers of this work were faced with very challenging task, which required resolving of many technical problems, e.g. the expected lifetime of device at least 25 years. This figure corresponds with the coal store in mines the North Bohemia region. The higher economy of the operation is expected, i.e. the lower content of emission in the boiler´s combustion products as well as lower values of the CO2 ratio per produced unit of electric energy.It had been obvious already in the initial phase of the solving that it would be necessary to carry out many experiments in cooperation with foreign research institutions as well, because in the Czech energy sector the concept of existing boilers in operation had not allowed it. The most important and the most difficult was the problem concerning emissions, especially NOx and CO. In the ETU the question of SO2 is handled separately, outside the boiler itself. Besides the retrofitting, at the same time it is also necessary to perform the solution of the boiler correctly, as this solution has to provide not only higher but long-term efficiency and reliability of the device as well. Problems of emissions, however, required considerably complicated organization of the entire combustion process, which was accompanied by more complex distribution and organization of the boiler´s air mode. This couldn´t be done without increase of the number of regulators on the air routes and eventually recirculated flue gas as well, which was confronted by dispositional problems during practical implementation, when it was required to consider boiler´s expansion as well as possibility of servo-drive´s location, very often in areas of higher temperatures.As a successful solution, there can be seen the new boiler´s expansion. The original one was based on a "fixed point", while the reconstructed boilers are designed in the way of independent expansion of the pressure system of the combustion chamber, and a next separate expansion unit composing the second boiler´s draft. Both of these independent systems are connected with textural expansion compensator, placed in the room under the boiler´s ceiling.A separate area is the design and organization of the measurement, including follow-up control system, which was very complicated when compared to the original concept of initial implementation of power station.(This original concept was upgraded in component phases a few times).There will probably be reserves in this area for other improvements, because the control system must sometimes keep even contradictory demands of autonomous control systems and sub-circuits. Management of these challenges requires considerable invention of workers, who may participate in this operation.In conclusion, the results of this thesis will be used in the process of creating other projects that are expected in the CR, or in other EU countries.