Design and Optimization of Coal to Hydrogen System Coupled with Non-Nominal Operation of Thermal Power Unit

Abstract

In an actual thermal power plant, deep peak shaving will cause thermal power units to run under non-nominal conditions for an extended period, resulting in serious problems such as increased equipment wearing, low equipment utilization efficiency and decreased benefits. To this end, in this work, both the design and optimization method for a coal to hydrogen system which is coupled with the expected non-nominal operation of thermal power units are proposed. Aiming towards maximum profit in the context of thermal power plants, a mathematical optimization model for a coal to hydrogen system based on the multi-period operating conditions of thermal power plants is established. The corresponding optimal design scheme of the coal to hydrogen system is determined using variable operating conditions. The superiority of the integrated system compared with an independent system is explored and the feasibility of the proposed method is verified by using the case study of an actual thermal power plant. The results show that compared with the independent system, the economic benefits of the integrated system can increase by 13.56%, where the sale of hydrogen in the coal to hydrogen system accounts for 60.3% of the total benefit. The main expenditure associated with the system is the purchase cost of feedstock coal, accounting for 91.8%. Since the required power and medium-pressure steam in the coal to hydrogen process are provided by thermal power units, the minimum operating load of the thermal power plant in the integrated system increases from 40% to 60.1%, which significantly improves the utilization efficiency and service life of the generator units. In addition, the proposed integration scheme of the system is simple and controllable, which can contribute to the maintenance of the safe and stable operation of power generation and hydrogen production processes. These results are expected to provide the necessary methodological guidance for the integration and optimization of coal-fired power plants and coal to hydrogen systems.