电厂粉煤灰库增容及增加干渣磨制系统可行性研究

电力行业作为基础工业,为国民经济的快速发展创造了条件。但随着国家对节能减排要求的不断提高,环保面临着越来越大的压力。本文主要对电厂粉煤灰库增容及增加干渣磨制系统可行性进行研究,并分析了项目实施的经济性。

湿法脱硫系统中石灰石磨制系统方案的比较

介绍了湿式石灰石磨制系统和干法磨制系统的工艺流程和技术特点,并对石灰石石膏法脱硫系统的主要辅助系统——浆液制备系统进行了技术、经济性分析。两种方法都可以满足脱硫系统对吸收剂制备的需要,但各有特点,为火力发电厂湿法脱硫系统制定技术方案提供了参考。

Design and Realization of Mineral Feeding SCADA System

The grinding process in concentration plants of the metallurgical industry is of great importantce.. A mineral feed- ing SCADA system in the grinding process was designed with the idea of integrating management and control functions. A detailed design and realization method of control and supervisory control levels in the system was introduced. At the control level, with an algorithm of a separate integrated PID, four mineral feeding machines are run in turn. The supervisory control level can generate process flow graphs, statistical report forms, historical trends and at the same time, it has the functions of alarm, system administration, user login, etc. After the mineral SCADA system has been started, the mineral feeding is very stable, the workstation completely supervises and controls the entire process of mineral feeding, and at the same time histori- cal data is shown and questions can be answered conveniently. The system runs well in the MeiShan Concentration Plant of the Shanghai Bao Shan Steel Group.

Active disturbance rejection control for hydraulic width control system for rough mill

The highly nonlinear behavior of the system limits the performance of classical linear proportional and integral （PI） controllers used for hot rolling. An active disturbance rejection controller is proposed in this paper to deal with the nonlinear problem of hydraulic servo system in order to preserve last response and small overshoot of control system. The active disturbance rejection （ADR） controller is composed of nonlinear tracking differentiator （TD）, extended state observer （ESO） and nonlinear feedback （NF） law. An example of the hydraulic edger system case study is investigated to show the effectiveness and robustness of the proposed nonlinear controller, especially, in the circumstance of foreign disturbance and working condition variation, compared with classic PI controller.

Discussion on Selection of Pulverizer and Moisture of Pulverized Coal for Lignite Boilers

In China,the abrasion index and the free moisture are regarded as the criteria for determining whether the medium-speed pulverizer or the fan pulverizer could be selected.Based on comprehensive studies on foreign methods for choosing the pulverizing system for lignite boilers,it is suggested that the particle size of coal,the drying time,the drying temperature and the humidity should be taken into account when measuring the free moisture of lignite,and the total moisture could also be the principle for type selection of pulverizer for lignite boilers.Furthermore,the determination of pulverized-coal moisture has great influence on the running of pulverizing systems.The actual moisture of certain pulverized coals is compared with that calculated with different methods and a feasible method for determining the moisture of the pulverized coal is suggested.

Improved Disturbance Observer (DOB) Based Advanced Feedback Control for Optimal Operation of a Mineral Grinding Process

Advanced feedback control for optimal operation of mineral grinding process is usually based on the model predictive control (MPC) dynamic optimization. Since the MPC does not handle disturbances directly by controller design, it cannot achieve satisfactory effects in controlling complex grinding processes in the presence of strong disturbances and large uncertainties. In this paper, an improved disturbance observer (DOB) based MPC advanced feedback control is proposed to control the multivariable grinding operation. The improved DOB is based on the optimal achievable H 2 performance and can deal with disturbance observation for the nonminimum-phase delay systems. In this DOB-MPC advanced feedback control, the higher-level optimizer computes the optimal operation points by maximize the profit function and passes them to the MPC level. The MPC acts as a presetting controller and is employed to generate proper pre-setpoint for the lower-level basic feedback control system. The DOB acts as a compensator and improves the operation performance by dynamically compensating the setpoints for the basic control system according to the observed various disturbances and plant uncertainties. Several simulations are performed to demonstrate the proposed control method for grinding process operation.

Disturbance rejection control for Raymond mill grinding system based on disturbance observer

In the Raymond mill grinding processes,high-accuracy control for the current of Raymond mill is vital to enhance the product quality and production efficiency as well as cut down the consumption of spare parts.However,strong external disturbances,such as variations of ore hardness and ore size,always exist.It is not easy to make the current of Raymond mill constant due to these strong disturbances.Several control strategies have been proposed to control the grinding processes.However,most of them(such as PID and MPC)reject disturbances merely through feedback regulation and do not deal with the disturbances directly,which may lead to poor control performance when strong disturbances occur.To improve disturbance rejection performance,a control scheme based on PI and disturbance observer is proposed in this work.The scheme combines a feedforward compensation part based on disturbance observer and a feedback regulation part using PI.The test results illustrate that the proposed method can obtain remarkable superiority in disturbance rejection compared with PI method in the Raymond mill grinding processes.