Atlas Copco discussed Class 0 and oil-free air in a seminar delivered at Process Engineering Live last week.
Anil Hingorani, project manager in the Atlas Copco Compressor oil-free air division, presented an overview of oil-free applications within the process industries and discussed why air purity is of vital importance to their operations.
Hingorani’s presentation covered the evolution of air purity standards, examining crucial differences between the second and first edition of ISO 8573-1.
It also covered the associated TUV test results and how they have been interpreted.
The presentation included an examination of some of the myths surrounding oil-free compression techniques and a question and answer session.
Atlas Copco offers oil-free and oil-injected compressors.
Compressor oil accounts for the majority of contamination in oil-injected compressor systems.
Relying solely on filters and dryers to remove oil leads to contamination risks.
There are three key failure risks associated with oil-injected compressor systems: that temperature rise will increase oil carry-over through the filters; that higher temperatures will severely reduce the lifetime of activated carbon filters; and that if filters become blocked because they are not changed in a timely manner, the filter will be bypassed and oil will enter the process.
The dominant factor influencing the purity of filtration systems is ambient temperature.
Oil carryover through filter media increases exponentially according to the temperature at the filtration interface.
Filter performance is often specified at 20C.
If the ambient temperature in the compressor room increases to 30C, the compressor outlet temperature could easily be ten degrees greater than that, increasing the oil carryover by a factor of 20-times the specified value.
A combination of oil-removal systems - oil separator, oil removal filters and refrigeration dryer - are the stages responsible for meeting the air quality specifications.
A failure of any one of these elements would result in contamination of the outlet air and the operator’s process.
A copy of Hingorani’s presentation is available on request.
This rock mineral wool production facility upgrade programme has resulted in a capacity increase to 33,000 tonnes of product per year, together with advances in material and product development as well as the introduction of new items.
An upgrade programme at Knauf Insulation’s facility at Queensferry has replaced/upgraded all parts of the production line, including the plant’s compressed air process.
High-quality compressed air plays a vital role, so keeping pace with the latest technology and energy-efficient compressed air solutions has been an important task for engineering manager, Philip Bishop.
‘In our specific applications, the compressed air has to be dry because condensation of water vapour deteriorates the quality of the insulation material,’ he said.
‘We look at the energy efficiency of plant equipment involved in our production processes in much the same way.
‘What is equally important to us is energy efficiency.
‘We find that Atlas Copco’s compressed air technique solutions have met both of these criteria,’ he added.
Atlas Copco’s relationship with the Queensferry plant started 10 years ago when it was invited to recommend a replacement for a competitor’s compressor plant installation, which was subject to overheating, oil leaks, had no drying facility and was allowing damaging moisture in to the air supply.
The ME box provides a true indication of a plant’s compressed air demand &, most importantly, any wastage that is incurred in producing it.
With the application of Atlas Copco’s measurement (ME) box survey techniques it was possible to establish a true indication of Knauf’s air usage.
Based on that information, it was possible to submit recommendations for the installation of the most energy efficient compressed air solutions available to match the company’s production needs.
The application programme employed enabled simulated compressor comparisons to be made against the actual technique operation and thus provide an indication of how the compressed air technique could be improved for maximum efficiency and reduced costs.
Compressed air is utilised for the air-atomised rock wool 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, an so on.
The company entered in to a five-year lease contract for the installation of a GA75 full feature machine also a GA75 VSD full feature unit.
Since compressed air does not come in to direct contact with done product within any stage of Knauf Insulation’s Queensferry production operations, it was decided that one Atlas Copco oil-injected rotary screw compressors would fulfil the process require and were selected to replace the existing plant.
one years later, the situation was reviewed to ensure that the installation was still relevant to the manufacturing processes.
Atlas Copco’s Airscan audit team got to work and presented new proposals based on simulations.
The recommendation and agreement was for one GA55+ fixed speed machines also a GA55VSD, all full feature machines with integral dryers.
Together with output controlled by an ES 130 unit and Airconnect remote monitoring, this combination allowed one fixed machine to run as a base load supply unit that could be topped up by the variable speed drive compressor or, on low production demand, to run the VSD machine by itself.
Furthermore, this decision satisfied Knauf Insulation’s primary considerations of total reliability and optimum energy efficiency.
This three-machine option also allowed for maintenance on any one unit without reduction in capacity.
To ensure that those standards were maintained at all times, the equipment was covered by a Total Responsibility Service Plan 1 contract with 24/7 support coming from Atlas Copco’s local service centre.
Atlas Copco Compressors has introduced the next generation in compressor controls across its oil-injected screw compressor range 11-90 kW GA/GA+/GA VSD.
The new fifth-generation Elektronikon graphical-display controller & the integrated Energy Saving (ES) Systems ES4/6i increase compressed-air efficiency, resulting in lower operating costs.
Atlas has expanded the Energy Saving (ES) technique to simultaneously control, with the ES6i, up to two variable-speed drives or fixed-speed compressors.
In addition, free online visualisation enables remote monitoring, allowing for anticipation of operating & maintenance needs.
The Elektronikon graphical-display controller is a colour display, housed on the compressor, that shows several compressor & dryer parameters while built-in algorithms automatically implement energy-saving cycles for fan & dryer.
Additional features such as dual-pressure band & timer-based controls enable Atlas Copco to maximise energy savings by matching the operating pressure to air demand.
The optionally integrated Energy Saving Control technique, ES6i, is capable of regulating & sequencing up to two variable or fixed-speed compressors.
It can also optimise the customer’s installation by reducing the overall working pressure-band of each compressor to meet the varying air demand.
Depending on the compressor configuration & air demand, the improved ES control technique can reduce yearly walking costs by up to 30 per-cent.
The possibility to manage up to two variable-speed compressors with one integrated controller (up to three compressors with the ES4i) reduces installation costs while minimising energy & maintenance costs through reduced pressure band.
The hardware innovations include a new human machine interface with durable keyboard & a user-friendly navigation technique.
This Elektronikon features a user-friendly interface that keeps the user informed about the operating condition of the unit.
The Elektronikon graphical display controller has a high-quality 3.5in colour display.
The built-in web-server technology uses Ethernet communication to provide instant online compressor-status visualisation.
The graphic visualisation provides service intervals in realtime & displays a graphical service plan assisting in preventive maintenance.
Customers can select one of 32 languages while all registered data is stored for later use.
The optional AIRConnect allows for remote or local monitoring (through the phone or wireless-internet connection) for additional on or off-line readings.
The Atlas Copco oil-injected screw compressor features efficient components (compressor element, coolers, motor) that provide premium performance in free-air delivery & specific energy requirements.
Coupled with superior controls, overall efficiency is increased further by complete technique optimisation, which results in reduced operating costs.