In order to improve the automation level of enterprise's paper industry, the 4400/600 high-speed paper machine produced by Shanghai Paper Machinery Factory adopts Hollysys DCS control system, which realizes the overall control of Shanghai Paper Machinery Factory. On the basis of introducing the composition and working principle of the control system, this paper discusses in detail the control process of the DCS control system of Shanghai Paper Machinery Factory and Lishi, and further expounds the advanced nature of the control system and the importance of cascade control. Practice has proved that the automation rate of the system can reach more than 95% during operation, which reduces the labor intensity of workers, realizes the huge economic benefits brought by the long-term safe production of the whole device, and promotes the rapid development of automation in the paper industry. I. Process Overview and Control Requirements

1, process overview

The production equipment uses wheat straw as raw material to produce corrugated paper. The 4400/600 high-speed paper machine produced by Shanghai Paper Machinery Factory has high production efficiency and stable product quality.

The whole device is divided into three parts: semi-chemical pulp workshop, paper workshop and waste paper workshop. Semichemical workshop is a pulping workshop, which makes wheat straw into pulp that can be used to make paper sheets; The papermaking workshop includes several parts: auxiliary material preparation, pulping and papermaking; The waste paper workshop mainly uses the purchased waste paper for deinking and pulping to make pulp. Because corrugated paper is produced, there is no bleaching process and no alkali recovery workshop in the semi-chemical workshop.

2. Process requirements of control system

Automation level requirements

This production equipment is newly built by this enterprise. Most of the original production lines of enterprises are operated by hand, and there are many basic instruments. There are operators with high intensity and large quantity; Low labor productivity; Unstable quality; It is difficult to increase production and so on. In order to get rid of this unfavorable situation, Galaxy Paper Company chose MACS system with advanced technology and stable system as the control system of the device when the project started.

Second, the control content

Semichemical workshop

Start and stop control of pump and motor, interlock stop.

Control of continuous steam engine

Control of refiner

Control of black liquor filter, etc.

Copying workshop

Start and stop control of pump and motor, interlock stop.

Control of auxiliary material preparation system

Mud mixing control

Three-level gas supply control, ventilation system control, etc.

Waste paper workshop

Control of two-stage fiber separator

Control of two-stage pressure screen

Liquid level control and liquid level interlock of each storage tank

Control of high concentration and medium concentration desander

Control of hydraulic pulper etc.

Third, application

According to the domestic paper market demand, Yinhe Paper Co., Ltd. put into production a set of 654.38+10,000 tons/year high-strength corrugated paper production line in 200 1 year. MACS system of Beijing Hollysys System Co., Ltd. was selected as the control system of this project because of its excellent product performance and the achievements of Hollysys Company in the paper industry. In June 2002, the project started smoothly and put into normal production. At the end of 2002, Yinhe Paper Company started the second phase project with the same scale as the first phase project, and the control system also adopted MACS system.

Fourth, the control effect and economic benefits

MACS system was successfully started and put into normal production in June 2002. The system runs stably, the control effect is good, the process indexes are normal and the product quality is stable, which brings great economic benefits to Yinhe Paper Company.