On-line reset control of a commercial-scale opposed multi-burner coal-water slurry gasification system using dynamic reduced-order model

Abstract

The entrained flows from four opposed burners enhance the mixing in a coal-water slurry (CWS) gasifier, which increases the extent of carbon conversion. Moreover, the operation of the opposed multi-burner (OMB) gasifier is more flexible because one couple of the opposed burners is allowed to be shut off for a certain period as long as the other couple is still running. Thus, the operation lifetime of the gasification system is determined by the ability to return the shut-off burners to operation, referred to as online reset control (ORC). However, the ORC is manual, which increases the operation uncertainty. In this study, we demonstrate an automatic control strategy using a dynamic reduced-order model (ROM). A reactor network model (RNM) of the gasifier, which considers several sub-models, is developed based on a flow field analysis and particle and gas residence time distributions (RTDs). The dynamic ROM and simulated manual ORC are verified using industrial data (5.8 MPa, 1500 metric tons per day (TPD)). An automatic control scheme for the ORC is proposed. The dynamic ROM is validated to be reliable when operating with the commercial-scale OMB CWS gasification system, as well as with its manual ORC process. The automatic ORC is promising for industrial gasification because the fluctuation ranges of the operation temperature and pressure of the gasifier are acceptable, which indicates that the reliable dynamic ROM can simulate a closed-loop control for a complex reactor.