Rockwool maker saves energy on compressed air
Compressed air is emerging as a notable opportunity for manufacturers to save energy, according to building materials producer Knauf Insulation, which recently upgraded its air compressors as part of a £10 million upgrade of its North Wales factory.
The company has invested in three new compressors from Atlas Copco, two fixed speed machines and one variable speed drive (VSD), all with integral dryers. This allows it to adjust its compressed air production according to demand, for example using just the VSD when demand is low.
The Knauf factory has a production capacity of 33,000 tonnes a year of rock mineral wool. Compressed air is used for the air-atomised binder sprays and for the reverse jet bag filters that handle fibre and dust, including recycling systems. It plays an important role in the plant's packaging machinery functions and for general plant air required for operating pneumatic cylinders, actuators for valves, dampers, bin doors, diverter chutes, etc.
"In our specific applications, the quality of the compressed air is very important," said engineering manager Phil Bishop.
"What is equally important to us is energy efficiency. Our corporate slogan is 'It's time to save energy' and we are very serious about it. Our company mission is to become world leader in energy efficient systems for buildings, so we look at the energy efficiency of plant equipment involved in our production processes in much the same way."
He noted that, as part of Knauf's factory upgrade, the company had Atlas Copco carry out an audit, measuring the plant's compressed air demand and the wastage that is incurred in producing it. The audit team then ran computer simulations to see how the compressed air system could made more efficient and cost-effective.
According to energy watchdog the Carbon Trust, as little as 8 to 10 per cent of the energy supplied to a compressor may be converted into useful work at the point of use. It suggests that auditing your compressed air usage and minimising waste, for example by fixing leaks, can save more than 30 per cent of the energy used.