Optimization of Waste Heat Recovery Power Generation System Applied in Ferroalloy Industry

During ferroalloy production, a large quantity of waste gas can be utilized to generate steam and electric power. In this paper, 4 detailed thermodynamic models of single-pressure (SP) and dual-pressure (DP) waste heat recovery power generation systems are presented, to analyze the impact of the steam pressure, steam temperature and pinch temperature difference on power generating capacity. By comparing the performance of typical systems, more reasonable thermodynamic models and their parameters are proposed. It is found that the power generation capacity of dual-pressure system is higher than that of the single-pressure system, but SP system is much simpler. Using superheated steam in deaerator reduces the efficiency of heat recovery power generation systems by 1.8%. The fluctuation of waste gas source affects the power generation greatly. It should be considered when more reasonable ranges for the main parameters are required. With the improvement of thermodynamic system and parameter optimization, the gross power is increased by 15% for SP system and 17% for DP system, corresponding to the steam parameters of 3.0MPa/400°C and 6.0MPa/400°C.