Plant & Works Engineering
Strategy for renewable energy manufacturing
Published:  06 March, 2015

As part of a strategy to further develop its specialist capability for renewable energy manufacturing, Mabey Bridge, a leading specialist supplier of high quality steel bridging, tubular structures and heavy plated steelwork, made a significant investment to add another 30,000ft2 to its Newhouse manufacturing plant, enabling the production of an additional 100 onshore wind turbine towers (more commonly referred to in the industry as canisters) per year. PWE reports.

An important part of this expansion was a new, larger fabricating facility to provide surface treatment processes such as blast cleaning using recycled steel grit, through to the final paint finishing stage.

A reliable source of quality compressed air is a vital factor in this large scale, industrial manufacturing and finishing process. Prior to the extension project, Mabey Bridge had been impressed with the performance of its original HPC compressed air system, supplied, installed and maintained by HPC Authorised Distributor, Compressor Systems (Wales) Ltd.

Depending on the final size of the turbine, the largest produce up to 3.6MW and the smaller turbines generate 235kw. Each supporting canister is made in either three or four sections, measures up to 36m in height, weighs up to 100t, have a steel thickness of up to 100mm and an overall diameter up to 5m.

The expansion of the surface treatment facility and the associated scaling-up of the fabricating and finishing processes demanded increased air capacity. However, it was also very important to ensure the ongoing energy efficiency of the system whilst coping with the new, greater variable demand.

A key requirement identified in the early stages of the consultation process was that the compressors for the blast cleaning, paint shop spraying facility and the fabrication area needed to be connected and able to work together. With each system supplying compressed air to the other and depending on the workflow, it needed to be possible to meet a combined varying demand of up to 84.9m³/min (3000cfm). It was also important that the two linked compressed air systems could provide redundancy, and it was essential that the new system ensured that the painting process could always operate uninterrupted.

After carefully considering the options and proposals from several experienced compressed air specialists, Mabey Bridge invested in the proven expertise of Compressor Systems (Wales) and HPC Compressed Air Systems. Having worked hard to establish a good working relationship with Mabey Bridge at the company’s other manufacturing sites, Compressor Systems (Wales) was able to demonstrate how the investment in a new variable speed compressor would complement the two existing HPC compressors working with them to optimise efficiency through periods of varying demand. In fact, they were the only supplier that identified and provided a solution to redundancy and for linking the two systems together through the latest HPC compressed air management, control and communication system.

At the heart of the new installation is the HPC SIGMA Air Manager (SAM) management and control system, a powerful industrial PC featuring HPC’s adaptive 3-D control. This sophisticated compressed air management system brings together the individual components of the compressed air system to ensure that compressor delivery volume is precisely adjusted to match actual demand (from both the fabrication area and the paint shop) saving energy and reducing operating costs.

Commenting on how the new HPC compressed air system has performed, Alex Wilson, production engineer at Mabey Bridge, said: “The variable speed compressor has allowed us to save energy by closely matching the supply and demand of compressed air whilst maintaining an accurate and constant supply pressure.

“The SIGMA Air Manager controls the installation perfectly, switching the compressors in and out to meet the sometimes large variations in demand. We really appreciate the SIGMA Air Manager (SAM) main control feature as it enables our three compressors to work in conjunction providing us with maximum flexibility and directly matching the supply of compressed air with the demand of our processes, whilst maintaining a constant system pressure. It also means that we can add compressors into our system and consider some of the impressive, additional communication and control features of the system as our process needs grow.”

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The Mabey Bridge compressed air system installed as part of the extension is:

• One off HPC ESD 442 SFC (250kW) rotary screw compressor with SIGMA Frequency Control.

• One off HPC SIGMA Air Manager (SAM) Compressor management, control and communication system.

• A compressed air treatment package including refrigerant dryers, compressed air filtration and condensate management.

The existing compressed air system at Mabey Bridge comprised:

• One off HPC ESD441 (250kW) rotary screw compressor.

• One off HPC DSD 238 (132kW) rotary screw compressor.

• A package of compressed air treatment products.