Blast furnace benefits from upgraded condition monitoring

Turbo-blowers and their control systems are crucial to the steel making process and Sensonics, a company specialising in condition monitoring, was delighted to play a part in a major project involving the relighting of the blast furnace at the SSI steelworks in Redcar, on Teesside. Originally a British Steel facility and formerly owned by TATA, CORUS, the site, which is the second largest blast furnace in Europe, was acquired by SSI (Sahaviriya Steel Industries) in 2011. The Cordell Group, a Teesside-based engineering contractor providing engineering services to the local steel industry for many years, was appointed by SSI to carry out a major upgrade of the Turbo-blowers control systems in 2011, including Sensonics equipment, some of which was originally installed in 1997.

The Turbo-blowers consist of a pair of axial flow compressors that are driven by fully condensing 54MW steam turbines with a normal operating range of 4200Nm/min at minimum blade angle, up to a maximum of 9350Nm/min at 6.2BarG. Each turbo blower is capable of supplying the total air demand of the blast furnace, with only one machine in continuous operation while the other is on cold standby. The output air flow of the compressor is controlled by means of variable-pitch stator blades with the machine running at constant speed, while the up/down of the blower is controlled local to the machine. During the starting and stopping phase of each blower, monitoring is performed by a local turbine panel adjacent to each machine. When the machine is up to speed, control of the unit is performed by the turbo-blower control panel located in a central control room.

New condition monitoring system

The new Sensonics condition monitoring system comprises a total of 15 sets of Senturion proximity probes monitoring a range of functions on each turbo blower, including relative shaft vibration, rotational speed and thrust positions.

These probes are connected to a protection system comprising a 19inch rack-mounted Sentry G3 monitoring and protection system retrofitted into the existing floorstanding panel, along with 16 channels of relative shaft vibration monitoring. The 14-channel Sentry G3 protection equipment provides a high-integrity protection configuration with two-out-of-three voted speed and two-out-of-three voted thrust position on both the turbo blowers.

Commenting on the new system, Graham Blackburn, the Control and Instrumentation Engineer for Power and Energy at SSI Redcar, states: "The need for careful monitoring of the condition of these machines when running is crucial and we have relied upon Sensonics equipment for the speed monitoring (3540rpm) and for axial displacement, for many years. Although the original Sensonics equipment was still serviceable, we decided to upgrade to the new Sentry G3 modules in 2011. The other Sensonics equipment installed earlier monitoring the 'X' and 'Y' vibration on the four bearings is also serviceable and providing the plant condition detail we need with peace of mind. Having seen the new Sentry G3 modules we are now planning to incorporate these during planned outages within the next two years on the four turbine alternators where we have also previously relied on Sensonics for our plant condition monitoring."

The successful upgrading of condition monitoring equipment at the SSI Steelworks in Redcar is another example of Sensonics operating as a leading supplier of turbine supervisory and high-integrity protection equipment to industry. Sensonics has over 30 years' experience in providing vibration, displacement and speed instrumentation systems for demanding environments. Not only can the company supply a full range of sensors and API 670 compliant measuring and protection equipment, but also design through, installation and commissioning.

Follow the links for more information about Senturion proximity probes and the Sentry G3 monitoring and protection system.