Control-oriented modelling and investigation on quick load change control of subcritical circulating fluidized bed unit. (25th December 2019)

• Record Type: Journal Article
• Authors: Zhang, Hongfu; Gao, Mingming; Hong, Feng; Liu, Jizhen; Wang, Xiaowen
• Is Part Of: Applied thermal engineering. Volume 163(2019)
• Publication Date: 2019-12-25
• Subjects: Operational flexibility -- Circulating fluidized bed (CFB) -- Mechanism modelling -- Dynamic characteristics -- Control of quick load change; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2019.114420
• Languages: English
• ISSNs: 1359-4311

Abstract

Abstract: The flexibility enhancement of circulating fluidized bed (CFB) power plant contributes to both power grid stability and renewable energy accommodation. The considerable energy storage makes it possible for CFB units to perform quick load change, while there are many CFB units cannot meet the basic requirement of load change speed from power grid. The study aims at realizing the quick load change control of subcritical CFB unit. With reasonable assumptions, a mechanism-based boiler-turbine system model of subcritical CFB unit is established to design control strategy. Through the analysis on energy storage utilization, a control strategy based on dynamic matrix control, which can overcome the large delay and inertia of CFB unit, is designed to realize the quick load change control. The simulation results show that the proposed control strategy can shorten the response time of the main steam pressure and accelerate the load change speed, while the traditional direct energy balance control strategy is unsuitable for quick load change control. Finally, a case study on the 300 MW subcritical CFB unit reveals that the load change speed can be raised to 3% of rated power output per minute and it almost takes no impact on operational safety.