High Efficiency Centrifuge: Performance Testing

You are eyeing a high-efficiency centrifuge? The term has been used in the industry to entice customers for lower energy costs, better separation, and a wider range of operation. But what are high-efficiency centrifuge capabilities, and how do you know it lives up to the hype? Is it in the brochure, or just another round of marketing with guaranteed specifications? The answer lies in the results of the performance testing. Would you take your centrifuge to the most qualified professional with a checklist to do a thorough medical examination? Most plant managers and process engineers absolutely understand what is involved in this testing process, and how to make a good investment to ensure that the operation of every machine in their plant is seamless. It is what separates truly exceptional process equipment from the rest of the pack. This article aims to provide performance testing knowledge for high-efficiency centrifuges, so you know what you are getting for your investment.

Let's unpack performance testing.

Let's start with a quick example. You would never buy a car without test-driving it first. The same kind of thinking goes into buying a piece of industrial equipment like a centrifuge. Performance testing goes beyond a formality of a manufacturer's 'test drive'. For you as the buyer, it provides validation. A performance test's fundamental aim is to confirm whether the centrifuge you plan to purchase, and incorporate into your production line, is capable of delivering what the purchase order states.

Arguably, the most important piece of the testing process is validation of separation efficiency. Does this high efficiency centrifuge consistently provide the required clarity of your liquid phase? Does this centrifuge provide the required dryness of the solid cake? The ultimate separation quality is what matters at the end of the day, especially when you are concentrating on producing pharmaceuticals, or processing chemicals and wastewater. A test will measure key output parameters against your specific feed material and remove all doubt on your final product and your bottom line.

Next, it is all about how much power does the machine consume. The so-called high-efficiency centrifuges must show how easy it is on the power meter. Performance testing closely considers how much power the machine uses. This is how you see if the new motor, new gearbox, and new control system make a difference for the better and lower the operational costs. The machine can claim energy savings, but it is a real claim if they can demonstrate it savings down to the pennies on the power meter.

Additionally, testing pushes the equipment to its breaking point to measure its construction and component stability and reliability. How does the centrifuge react to a full operational cycle? How does the equipment perform during a rapid tear and wear cycle to see how the machine performs under abrasive conditions? How does the machine perform under high heat conditions? How does the machine perform during high operational deflection? The machine will show signs of heat distress in the form of high wear on machine components, high bearing temperatures, high levels of vibration, and high levels of noise. Those signs can be indicators of future high maintenance problems. In short, testing the machine helps minimizes risk and provides confidence that the centrifuge functions to perfection and is not one of the blinged out false performaning centerpieces.

Factors Examined Closely

Performance testing isn't just a single measure. It's a piece of a larger puzzle. Each parameter gives a portion of the story about the condition and capacity of the machine. Having insight into what the technicians are taking measurements of, lets you know what to pay attention to in the test report.

Separation efficiency is, we’d say, the shining star. This is evaluated by checking the solid content of the centrate, aka the run-off liquid. The lesser the solid content, the greater the separation performance. On the other hand, with the solid phase, the emphasis is on residual moisture. The lower the moisture in the cake, the lesser the volume to be disposed of, thus greatly reducing hauling costs. A true high efficiency centrifuge excels at both, delivering a beautifully clear centrate and a super dry solid cake. It achieves optimal recovery while having minimal waste.

Next up are capacity and throughput. For throughput, you are looking to answer how much material can this machine process over a defined duration of time. This answer is derived from running tests at various feed rates to determine the sweet spot, or the optimal maximum throughput at which the machine displays a consistent high level of separation efficiency. If you exceed this rate, the performance of the machine will quickly start to deteriorate as it becomes overworked. This test will also determine the performance of the machine to answer your specific needs and ensure that your production requirements will be met.

Power consumption is one of the most important factors when it comes to efficiency for any high efficiency centrifuge. It is one thing to read the kilowatt consumption from the meter, a more important piece of information is to analyze specific energy consumption (SEC). This is defined as the amount of energy that is expended for each unit of material that is processed. This allows you to compare various machines operating under diverse conditions. If the number is dropping, you can safely assume that operating costs of the machine are decreasing and that the machine is becoming more efficient. To determine the electrical efficiency of the motor system, the power factor is also measured.

Mechanical Integrity Parameters Are The 'Vital Signs' of a Machine.

Why Is Vibration Analysis Important?

Engineers can use the sensors they place on the bearing housings to identify minor imbalances or misalignments. Smoother, lower-vibration operations are characteristics of excellent engineering and manufacturing. Another indicator of the system's health is bearing temperature. Rapid and excessive temperature increases reflect poor lubrication and impending bearing failure. Noise is also monitored, as excessive noise level deterioration can reveal mechanical problems and create a poor working environment. These parameters combine to provide an overview of the mechanical reliability and longevity of the centrifuge.  

From The Setup To The Data Analysis – The Testing Journey Is Structured  

Performance Testing is a structured journey consisting of Setup, Data Collection and Analysis, and is the most efficient way of getting meaningful insights on the centrifuge's performance.

To begin, we need to set up and calibrate everything. Next, we set up the centrifuge to a test rig, and make sure to account all our needed resources; flowmeters, pressure transducers, power analyzers, and for our resources with temperature, we will install some thermal sensors as well as some to measure vibrations and heat. Then we make sure to calibrate everything to know all our input and output data will be valid. And finally, we will set up the test slurry to the same specifications as the materials to be tested in our customer’s plant for testing of real-world situations. Consistency in materials is crucial to getting valid and reliable results.

When the tuning is done, the testing phase is next. This phase is often a number of steady-state runs, where the centrifuge is run at a constant speed and feed rate, and all of the parameters have stabilized. Parameters initialized for vibration, temperature and power draw cycles, and log data for number of runs. Once the logs have been completed, the run conditions change. An increase in feed rate, change in bowl speed, or differential speed of the conveyor are often modified during this stage. This is done to trace the machine's performance, or to create a profile of the machine. The objective is to analyze the performance of the machine at different constraints and conditions. The goal is to understand not just how it runs at a singular optimal performance point, but how elegantly and efficiently it runs at different parameters.

At LAST we have the post-test analysis and the reporting phase. Raw data is processed into valuable actionable insights. Data Engineers process the data into visual graphs and charts that determine the relationship between feed rate and cake dryness; or bowl speed and power consumption. They do a thorough investigation if there are unique trends with respect to vibration and temperature to determine if there is a mechanical issue. In the final report, the data is presented professionally with a proper analysis of the data trends. The report states with clarity whether the centrifuge successfully accomplished the performance guarantees and what the main benefits and risks are. This report is a key part of the reference material for the entire lifetime of the equipment.

Analyzing The Results Like An Expert

A long test report can be overwhelming. However, concentrating on certain performance aspects can be helpful. The goal is to find a correlation between the machine performance and the data presented in the report.

To find the report contract verifications first, look through the performance guarantee cross-checks. This means, look for the performance guarantees listed, like maximum throughput, target cake dryness, specific energy consumptions, etc., and look for actual test results track records. This side-by-side evidence is the most simple example of confirming whether the machine completed the work tasks needed of them. Do not just verify if the machine completed the tasks, see by what value or margin did they complete them by. A machine like this that is performing over the expected limit is most certainly built with excess margins for moving the process steps around your future work alterations.

Following that, look through the performance curves, which are some of the most telling sets of data. For example, a curve plotting cake dryness against the feed rate should have absolutely stable, and gradually declining intervals for each increasing feed rate. A curve with erratic and sharp drops, is a machine that is likely not very robust and has a narrow optimal operating window. Furthermore, a power consumption curve that rises steeply with an increasing load is likely not as efficient as one with excessive load steps and a more gradual increase of slope. The character and flexibility of the machine is what this data is telling us.

Note trends Mechanical data trends. Examine machine vibration and temperature data throughout the test. In the ideal case, we get a graph showing steady line results with no fluctuation. Small, random variations are fine, but if there is a pattern spike, or a steady upward creep, that’s a bad sign. This data is an indication of the intrinsic maintainability, lifespan, and overall cost/benefit of the machine. Mechanical stability centrifuges are cheaper to maintain and have better uptime. In the end, stability is assessed on the basis of the machine’s operational and economic viability, but also based on how stable it can perform this function for long periods of time.  

Long-term Benefits of Detailed Testing  

Taking the time to do an extensive performance test might feel like project delays, but this is an optimization of the smartest order. Benefits of time and resources invested go far beyond the first acceptance of the machine and pay off throughout the operational life of the machine.

First, let's talk operational cost savings. Having a tested, efficient centrifuge specifically reduces energy expenditure, in addition to reducing the cost to dispose of waste. Machines that produce a dryer cake further reduces disposal costs. Having validated efficiencies allows you to more accurately project operating costs, thus increasing profitability for the plant. You're not only purchasing a separation machine, but also a fixed cost structure for the separation process.

And let's not forget the operational reliability and uptime, which are off the charts. During testing, potential mechanical failures are pinpointed and addressed before the equipment is delivered to you, preventing unplanned downtime, failures, and subsequent production line halts. Comprehensive testing and validation of the equipment delivers priceless peace of mind. Maintenance is also able to plan their operational downtime around the stress-tested equipment, enabling more efficient and reliable operational downtime and predictive maintenance schedules.

Lastly, performance testing sets a benchmark for performance. Detailed data created during the performance test offer a detailed digital fingerprint of the machine in optimal, brand-new condition. After several months, if a change in performance is noted–perhaps increased machine vibrations or higher energy consumption–the current data can be referenced against the original baseline. This makes diagnostics faster, more precise, and objective. Maintenance is no longer a reactive task. It can be predictive. Over the years, a well-tested high-performing centrifuge turns from just a piece of equipment to a keystone of a well-oiled, high-efficiency production operation.