Implementation of Blast Furnace Gas Water Spray Cooling Cont

Implementation of Blast Furnace Gas Water Spray Cooling Control System Based on PLC and OPC

Minggang Zheng, Zhifang Jiang, Xiaohui Zhu School of Mechanical and Electrical Engineering

Shandong Jianzhu University

Jinan, China

Abstract—An automatic control system based on PLC was panel and ABB ACS510 frequency converter. The hardware

designed according to big flow, high temperature and maximum structural diagram of the system is shown in figure 1.

cooling temperature 55 of the blast furnace gas. To realize closed-loop control of temperature, the system collected inlet and outlet gas temperature using temperature sensors. According to the change in temperature, PLC automatically changed the working water spray capacity by regulating the output frequency of frequency converter automatically. Considering the big noise and long distance from monitoring room, a remote control system was designed to help operators in DCS control room monitor and operate the water cooling equipment. The system enhances the automation of water spray cooling system, and it has great practical and spreading values.

Keywords-Siemens S7-200PLC; OPC; water spray cooling system; remote control

Figure1. Hardware structural diagram of the system.

I. INTRODUCTION

There is a set of electrical control cabinet, which is mainly PLC controller, AD/DA converting module and touch panel (HMI). All the parameters can be directly set by HMI or the remote control computer. There are also signal insulation modules and low voltage electrical component parts in the control cabinet. Manually open inlet ball valve v20 of the gas circuit, the inlet and outlet ball valves v11, v12 of the filter. Start II. SYSTEM INTRODUCTION AND WORKING PRINCIPLE

the solenoid value B21 of the gas circuit and pneumatic control valve B11 at first, the gas circuit starts to work, then start the 2.1 System Introduction

The system consists of host computer (remote control water pump P11 or P12, one pump works and the other prepares computer), PLC controller and extended modules, 2 frequency to work, and the lance begins to spray water at this moment.

The system collects the inlet and outlet hot resistance converters (one-work, one-standby), 2 water pumps (one-work,

one-standby), main water circuit, main gas circuit, water spray temperature and automatically generates frequency converter mechanism (grouping control cabinet and two-fluid lance) and opening, working water jet capacity of the lance, and the

number of the working lance according to the target temperature measuring control system.

temperature so that the outlet temperature can meet the

The hardware of the system: Siemens S7-200 PLC requirements. When stop the system, close the frequency CPU226, digital I/O module EM223, analog modules EM231, converter and water pump at first, and water supply stops at EM235, the extended slave station module EM277 once, after some time (can be defined), stop the solenoid value

B21, and the gas circuit stops. The system automatically turns to PROFIBUS-DP, Siemens PC547B IPC, Siemens bus connector

and interface card CP5611, Siemens K-TP178Micro touch

The blast furnace gas can be used as personal fuel gas in metallurgical enterprise and can also be supplied for civilian use after dust abatement. The required gas temperature of the gas pipeline is below 55 , but the temperature of the gas from TRT is still above 180 , so it is necessary to reduce the gas temperature with spray water before the gas entering gas pipeline. Because of the big noise in working site, two ways-local control and remote control are set in the water spray cooling system. IPC of the remote control is located in TRT control room, which is convenient to operate and monitor the device for the workers. The system can greatly improve the recoverability rate of the blast furnace gas, and it also has significant environmental and economic benefit.

2.2 Working Principle

The two-fluid lance sprays water in the direction of gas flow. The system controls the main water circuit and the main gas circuit according to the selected parameters (water pressure, gas pressure, the number of the working lance and the target temperature). The cooling water absorbs heat and evaporates by mixing with hot gas in mist form to reduce the gas temperature. The temperature is measured by hot resistance, one in inlet and two in outlet. The control system checks the inlet and outlet temperature to realize PID closed-loop control. Working principle of the whole system is shown in figure 2.