Study Of The Thermal Performance Parameters And Dynamic Characters In The Supercharged Boiler

Supercharged boiler is one of the main power plants for steam power plant, the thermal performance parameters and dynamical characters are different from the conventional boilers. This thesis takes the supercharged boiler of model "КВГ4" as the researching project, does the analyses and unscramble on the key problems of supercharged boilers in the level of physical mechanism with theoretically analyzing and mathematic calculating.Firstly, combining the experience on designing traditional marine boilers for reference, with the data of practical measuring and working performances, on the base of the theory of Heat transfer and Combustion, the theoretic charts of supercharged boilers were drawn for the first time, the thermal calculating methods of supercharged boilers were determined, and the thermal calculation of full and fractional loads were gained. Secondly, the profiles of main performance parameters versus different loads in steady working condition were achieved by theoretically analyses and calculation, the enhanced combustion with pressured gas and the mechanism of heat transfer with the gas flowing were investigated in theory. Thirdly, using lumped method, the mathematic simulation models of dynamic parameters were built for different apparatus respectively, which were applied in the commercial simulation software to do numerical simulation, and the profiles of dynamic parameters were achieved.From this thesis's research, some outstanding conclusions were gained as follows. The calculation methods selected in thesis are suitable for the thermal calculation of supercharged boilers, which may require further modifying with the test data of land test-bed and practical measurement. The temperature of superheated steam produced in low loads is very low, which may reduce the efficiency of boiler and the whole system, so it requests improvement on the structure. To compensate this shortage, the semi radiation-superheaters may be adopted which can provide steady temperature of superheated steam in different loads. The drag forces in the inlet and outlet pipelines of "КВГ4" are too large to have the power equilibrium point, which result in the requirement of additional power from assistant steam gas turbine. The time of start-up is shorter with the wastage of fuel increasing, and the pressure increases sharply. The parameters of steam and exhaust gas in superheater change quickly and exquisitely, when there is a disturbance from outside.