Compressed air balancing in a rolling mill

Compressed air measurements in the compressor systems to balance the generation quantities and consumption levels

Vallourec Deutschland GmbH operates two hot rolling mills at the traditional location in Düsseldorf‘s Rath district, where seamless steel pipes have been manufactured using the ?Mannesmann process“ since 1899: The pilger line produces premium quality pipes with an outside diameter of 241 mm to 711 mm using the pilger rolling process, while the neighbouring plug line produces quality steel pipes with an outside diameter of 178 mm to 406 mm as well as square and rectangular hollow sections.

The ?Central Technical Service“ department is responsible for supplying both production plants with water, energy, and compressed air. The compressed air, which is primarily required for pneumatic drives and for blowing out pipes, is generated in two compressor stations and distributed over the entire plant at pressure levels of 6 bar and 8 bar. The quantities of compressed air generated must be measured to record consumption as part of energy management in accordance with ISO 50001 and for cost allocation. In the past, thermal mass and vortex flow meters were used for this purpose. Both measuring techniques are subject to wear and tear. The thermal mass flow meters must be calibrated regularly. Calibration, maintenance, or the replacement of defective measuring devices requires the respective line to be shut off, i.e. an interruption in the supply, and causes a great deal of effort for the necessary pipework. The technicians from the central technical service were therefore looking for a permanently wear-free measurement solution that would not impair plant operation.

The Solution

Once again, FLEXIM’s clamp-on ultrasonic technology proves to be the best measurement solution. A change in technology is usually associated with certain risks. However, not the switch to non-invasive flow measurement with FLUXUS?. Since the ultrasonic transducers are simply mounted on the outside of the pipeline, the user is convinced of the suitability of the acoustic measurement technology without any risk. This is usually done first with a test measurement, which is also the case at Vallourec in Düsseldorf. A home game for Axel Dickfeld, FLEXIM sales engineer in the field. With his portable FLUXUS? G601, he easily demonstrated the basic suitability of FLEXIM‘s clamp-on ultrasonic technology for the measurement task on a 6-bar line. As a result, Vallourec decided to initially fit the 6-bar compressor system with a stationary FLUXUS? G704 CA ultrasonic system to record the amount of compressed air generated there. Low-frequency GRK1N52 ultrasonic transducers, which stimulate the pipe wall with Lamb waves, ensure a strong measurement signal. Immediately next to the flow measuring point, a clamp-on Pt100 sensor also records the temperature non-invasively. The transmitter calculates the standard volume flow from the actual volume flow, temperature, and the pressure fed in via a current output.

Since the clamp-on compressed air measurement also proved to be convincing in continuous operation, the 8-bar compressed air station has now also been fitted with a FLUXUS? G704 CA. A third FLUXUS? G704 CA measures the compressed air consumed by a blasting system and an upsetting press on a DN50 pipe. An additional advantage of acoustic measurement technology is its extraordinary dynamics. Unlike the thermal mass flow or vortex flow measurement, the ultrasonic measurement does not require a minimum inflow. As a result, even low consumption is now reliably recorded for the first time.

Advantages

• Reliable and accurate non-invasive recording of compressed air quantities (standard volume flow)
• Simple installation without interfering with the existing piping system with minimal assembly work and without the costs for additional fittings and piping work
• No wear and tear, no maintenance and calibration costs
• High measurement dynamics also enable the recording of small consumption quantities

Measuring Points and Instrumentation

Pipelines: steel, DN200 and DN50

Medium: compressed air 6 bar, compressed air 8 bar

3 stationary clamp-on FLUXUS? G704 CA ultrasonic systems

2 pairs of clamp-on ultrasonic GRK1N52 flow transducers (Lamb wave) for gases, mounted in VARIOFIX L

1 pair of clamp-on ultrasonic GRP1N52 flow transducers (Lamb wave) for gases, mounted in VARIOFIX L

3 clamp-on Pt100 temperature sensors

“Interruptions of supply and high costs for necessary calibrations and pipework are now a thing of the past with FLEXIM’s non-invasive flow measurement technology.“

J?rg Zacharias, Energy Department, Vallourec, Düsseldorf-Rath Plant

Customer

Vallourec Deutschland GmbH, Düsseldorf-Rath Plant, Germany

Vallourec is a market leader in premium tube solutions for the energy markets and industrial applications. The products and services are used in challenging oil and gas wells, in almost all fields of application for renewable energies, in unusual architectural projects, and in high-performance machines and systems. In over twenty countries, around 17,000 employees work with their customers and help them to realise even the most demanding projects. Vallourec Deutschland GmbH is a 100% Vallourec subsidiary. The company operates two tube plants with different manufacturing processes in North Rhine-Westphalia (Düsseldorf and Mülheim an der Ruhr) and a globally unique research centre in Saxony (Riesa). Vallourec Germany, employs around 2,400 people.

For further information, please contact FLEXIM:

[email protected], flexim.com.