With the extensive application of renewable energy generation, thermal power units are required to participate in peak-regulating operations. The mode of steam distribution significantly influences the economy when the steam turbine operates at a low load. The turbine unit’s governing valve characteristics and steam distribution modes are studied in this paper, and the optimal sliding pressure operation curve is derived. Firstly, the theoretical model of the governing stage and the governing valve is derived, and the reliability is verified with field data. Secondly, the overall simulation model of the turbine unit is established, and the turbine off-design performance is analyzed with variable main steam pressure. Finally, the advantages and disadvantages of the three steam distribution modes are discussed thoroughly. The steam distribution modes and optimal main steam pressures are analyzed. The results show that a precise composite sliding pressure operation scheme is recommended, and a sliding pressure operation mode is adopted under 470 MW and constant pressure operation for others.

In this paper, the separation characteristics of mist remover in a wet flue gas desulfurization system are numerically simulated, and the separation mechanism in the channel of mist remover is analyzed considering the influence of droplets on wall recombination, diffusion, and splash. Considering the influence of re-entrainment, a gas–liquid separation model was established to reflect the coupling effect of air flow, droplets, and liquid film in the process of defogging. A computational model based on the energy loss coefficient κ was established, and the numerical simulation of flue gas flow in a single channel of a baffle demister was carried out using the computational fluid dynamics method. The effects of plate distance, plate angle, droplet diameter, and flue gas velocity on the separation efficiency were simulated and analyzed. Based on the response surface method, the model for separation characteristics and structure optimization design of the demister is established, and the influence level of each factor is analyzed.

In this paper, the spray tower of a wet flue gas desulphurization system in a coal-fired power plant is studied. The flue gas and slurry droplet are two-way coupled with Euler-Lagrange method. The heat and mass transfer and the ion reaction in SO2 removal are also considered. The results show that the error between simulation removal efficiency and practical value is within 5% under the above models. Adjusting liquid-gas ratio and opening spray layer are beneficial to the SO2 removal, and the optimal liquid-gas ratio is 16 L/m³. Balance gas velocity is needed, because an overlarge velocity will significantly reduce removal efficiency.