Novel coordinated control method with coal-quality correction of circulating field bed boiler
To improve the load-following capability and the coal-quality applicability of a circulating field bed boiler (CFBB), a new coordinated control method with coal-quality correction is proposed in this paper. This method takes the primary air as another new control variable into the coordinated control of CFBB, which can take advantage of the unburned carbon in bed to improve its load-following capability. Simultaneously, a multivariable predictive controller based on augmented state space model is designed to deal with the CFBB's characteristics such as time-delay and strong coupling. Finally, an improved strategy to correct coal-quality online based on the disturbance observer is provided. Compared with the conventional control scheme, the simulation results for a 330MW CFBB shows that the method proposed in this paper can significantly improve the load-following capability and the coal-quality applicability.
A Steam-Temperature Adaptive Series-Step Control System for Circulating Fluidized Bed Boilers of Giant Domestic Manufacture
Due to the high order, the lag and the varying parameter characteristics of the steam temperature for circulating fluidized bed boilers (CFBB) and the full-coefficients adaptive control theory, a steam temperature adaptive series-step control system is put forward. The control system effectively eliminates the harmful effects caused by the controlled object's the high order and the lag and the varying parameter characteristics. The system is simple and practical, and has an engineering value. The system is applied to a worksite and good control result is obtained. Figs 5, table 2 and refs 2.
Mechanics of deformable directed surfaces
Abstract The paper develops a simple, yet complete and consistent non-linear dynamic thermo-elastic shell theory based on the concepts of a two-dimensional directed continuum. The constitutive equations are postulated in a general form. Stress-strain relations are derived using the equation of energy balance and the two entropy production inequalities, which are rewritten in a special form. The linear theory is discussed in detail. The structure of the stress-strain relations is presented in the most general form and then specialized to concrete examples, in particular, to the classical shell theory, using their invariance properties with respective to certain symmetry groups. The elastic moduli are determined by demanding the coincidence of the frequency dispersion surfaces obtained using the two-dimensional theory with the lowest foils of the corresponding surfaces resulting from the three-dimensional theory of elasticity.