Measurement and Monitoring of O2 Concentrations in Steel Mill Reheating Furnaces

Introduction

A furnace for heating slabs needs to be operated under low oxygen conditions at high temperatures of 1000℃ and above to prevent oxidation of the steel. The measurement of oxygen concentrations in the furnace is essential in this process.

The ZR22G/ZR802G Zirconia Oxygen Analyzer requires no sampling system and utilizes a long-life sensor, and is therefore ideally suited for measurement of oxygen concentrations in a hightemperature environment. The ZR22G detector with the ZO21P high temperature probe adapter can be used in gas furnaces at temperatures up to 1400℃.

Expected Benefits

• Maintains high product quality by monitoring oxygen concentrations in steel mill reheating furnaces
• Ensures stable, continuous measurement of oxygen concentrations
• Reduces operating costs

Process Overview

Slabs are loaded on a conveyor and fed to a reheating furnace, which is heated to between 900 and 1400℃ by burners that use fuels such as by-product gas. In order to keep the oxygen concentration between 1 and 2%, it is monitored in the preheat, heat , and soak zones. The slabs are heated uniformly without being oxidized, and then sent to the next processing stage.

Solution Details

Field Data

Process conditions
Measurement point:	furnace reheat, heat, and soak zones
Temperature:	900°C to 1400°C
Pressure:	30 to 50 kPa
Dust:	Trace
Fuel:	Gas

Measurement system

Detector:	ZR22G-015-S-Q-☐-☐-☐-E-A/CV
High temperature probe adapter:	ZO21P-H-☐-☐☐☐-☐*B
Auxiliary ejector for high temperature use:	E7046E☐
Converter:	ZR802G-☐-☐-N-N/☐
Flow setting unit:	ZA8F-☐*C
Calibration gas unit
Pressure regulator for gas cylinder:	G7013XF (inlet W22, outlet Rc1/4) or G7014XF (inlet W22, outlet 1/4NPT)
Case assembly for calibration gas cylinder:	E7044KF

Note: the calibration gas cylinder must be purchased locally.
 

Probe Adapter