What makes centrifugal compressors useful
Centrifugal compressors, sometimes called a turbo compressor, are dynamic compressors which means it relies on Bernoulli’s principle.
Centrifugal compressors use an impeller disk, which is a rotating element. Air is pulled into the center of the eye of the impeller disk from an inlet. The inlet is set at a 90-degree angle perpendicular to the eye at the center. The impeller disk is divided like a pie by curved impeller vanes. And along the edge of the impeller disk is a diffuser vane and a volute casing. The impeller vanes, diffuser vane and volute casing all contribute towards raising the pressure of the air. For contestant flat air flow demand centrifugal compressors have the best fit when it comes to larger flow rates above 4000m3/h with the lowest specific energy requirement , though the machine performance and output affected by ambient conditions but in cost benefit comparison energy cost in total comes in the advantage of centrifugal compressors over 15-20 years of total running cost reduction from energy .
Centrifugal compressors are in demand for multiple reasons. They are mechanically and energetically efficient over long duty cycles. They have a higher flow rate than positive displacement types of compressors and a wide range of rotational speeds. They are great as oil-free machines because they have fewer rubbing parts, they have low weight, low running costs and much lower down time for maintenance as the they need one service intervention per year with very few consumables , accordingly the design of the unit need to be very simple reliable with quick easy access to.
Factors to consider when choosing your centrifugal compressor
Horizontal or vertical split gearbox
Centrifugal compressor rotating at very high speed and balancing their gears is very accurate activity, with horizontally split gear arrangement beside being more reliable design with equal distribution of gas forces also allow easier maintenance and inspection access compared to vertical design.
Hydrodynamic bearings (tilting pad design)
Centrifugal compressors work at very high speed and requires reliable bearings type with the lowest down time , accordingly as per the experience and field proven tests, tilting pad design hydrodynamic bearings proven to be the most reliable type of bearings easier for maintenance without removal of the complete core unlike the older design fixed geometry.
Stainless steel coolers
Cooling of air between the different stages is key for the compressor performance and agility, stainless steel is a must as material for middle east saline ambient conditions, though copper have lower cost and higher conductivity but it tends to fail and corrode quickly which cause complete collapse of the centrifugal units.
Integrated package
Centrifugal compressors should be factory pre-packaged, wired, connected for plug & play operation. This includes internal piping, coolers, motor lubrication, inlet guide vanes, control system.
Easy to connect cooling water manifold as one connection that serves intercoolers, aftercoolers, oil cooler and main motor.
Look for main shaft driven oil pump with a breathing system to prevent oil fumes (guarantees 100% Oil free air)
Optimized energy use
Integrated Blow-off valve: Auto-dual and Constant Pressure control mode for cost-efficient variable demands Design should allow a turndown of over 25% before blow-off, maximizing energy savings. Additionally, IGV’s (Inlet Guide Vanes) should be servo motor controlled for accuracy to help achieve over 9% more energy savings on reduced flows.
Impeller
Dedicated impellers for each power and pressure variants. Backward leaning impeller design for greater operating flexibility and maximized turndown ratio of up to 35%. This design offers power savings at fluctuating demands.
Reduced installation cost
No external air supply for instrumentation and additional mounting - easier connections and operation. Integrated lube oil system reduces space and installation cost.
Faster maintenance or serviceability
Horizontally split gearbox with quick access to gears, bearings, and air/ oil seals. Bull gear & high-speed pinion arrangement - gear quality: AGMAQ-13/ISO 1328-2 A4 offers longer lifetime, minimized mechanical losses and lower noise levels, and is fully interchangeable of individual components.
For easier removal and maintenance, it is best to have the compressor core separated from cooler and subframe.
Silent machine
Inlet filter is combined with a silencer to reduce noise level and protect the compression stage. Soundproof canopy ensures optimal working conditions for the machine and environment around.
Compact design
Machines with lowest footprint are compact and easier to maintain and as well allow saving up on premium space.
Conclusion
There are multiple types of centrifugal compressors such as centrifugal blowers, oil-free air centrifugal compressors and process gas multistage compressors. Each has their own ideal applications based on things like your output pressure requirement.
If you’d like to learn more about our centrifugal compressor products and speak with someone from our team in the UAE, get in touch with our expert today.
