Experimental research on the characteristics of co-combustion coal and combustible gas has been carried out. The influence of nozzle position and combustible gas reburning ratio on N2O and NO removal rate were carried out at CFB experimental platform. It is found that N2O removal rate achieved a maximum value when the reburning gas was injected into furnace from nozzle C with a height-diameter ratio of 8.3, and the NO removal rate is about 50%; When the combustible gas were injected into furnace from nozzle C, the N2O removal rate kept increasing with the increase of reburning ratio (Rm), which can reach 99% when the Rm value is 10.5%. In addition, the NO removal rate is increasd after the first reduction with the increase of Rm, when the rate is about 39% with Rm is 10.5%.
Energy-saving and improving energy utilization efficiency are common concerned topics of the whole world. Control quality of reheat steam temperature is an important factor for thermo economy, which is mostly controlled by mankind and leads to uneconomical operation. One of the reasons is unsuitable controller parameters, causing by inaccurate models. In this paper, reheater model was established based on single-phase heat-exchanger thermal system dynamics. And parameters of the model were determined by design manual. Simulation on a 1000WM unit showed that, the model had good dynamic and steady performance.
The distributions of exergy dissipation in a 1000MW coal-fired power plant under different operation conditions were analyzed. Mass and energy balance models of different components were constructed to determine the thermodynamic properties of each stream. A variant of exergy analysis, the proposed equivalent specific fuel consumption (ESFC) analysis, were conducted to determine the additional specific fuel consumptions (ASFC) of individual component and, therefore, to obtain the characteristic of its temporal and spatial distribution. The off-design modeling of main components was established. The methodology and results of analysis in this paper can be taken as valuable guidance for the optimal design and operation of thermal power plants and for the improvement and retrofits for more cost-effective and environmental-friendly power plants.
This paper designs the pitch controller synthesis to ensure the stability and the controllability in the whole regions as the power grid scheduling instructions. Because of the wind speed measurement and accurate system model are hard to obtain, the range that the actual working point deviating from the balance point is very large, so that the system dynamic performance cannot be described with linear time variable (LTI). This paper utilizes the linear matrix inequalities' techniques (LMI) to design LPV (linear parameter varying) gain-scheduled controllers based on criteria, which provide guarantees of stability performances along the whole reference trajectory. The LPV pitch controller replaces the traditional speed controller to dynamically compensate the pitch angle. According to the errors between the power grid scheduling instructions and measuring the output power, power controller adjusts generator torque to achieve the adjustable power in the whole regions. In view of unmodeled dynamics and wind speed random disturbance, the feed forward linearization. robust pitch regulation using extended state observer (ESO) is proposed to restrain comprehensive disturbances. The proposed controller is seen to be more efficient.
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