Benefits of a centrifuge

Looking to improve the efficiency of your brewery, increase yield and decrease waste – think centrifuge.

If we look at the Pay Back Period (PBP); PBP=total cost of investment / annual cash flow we can get a general idea of how long the machine will take to payback. You increase the annual cash flow by:

     Reducing product loss

     Decreasing tank residence times

     Increasing throughput capacities

     Increasing labour efficiencies

     Zero DE purchase and waste

     Decreasing DO pickup

     Reducing maintenance cost

     Increase the chance of turning more tanks per shift

     Increasing the brewery’s flexibility

In general, most customers see an ROI of around 14-20 months; in some cases less. This all depends on current values along with the ability to turn those negative values that are contributing to loss & decreased efficiency, into positive values.

If we look at a brewery with 4800hl of fermentation capacity. Then what are the savings?

Section 1: Tank Residence Savings

Typical Process is:

     7-14 days fermentation

     2-3 days cooling

     10-21 days conditioning

Based on the ratio of 80% lager to 20% ale with cider being brewed as well it is safe to say that the average tank residence is 35-38 days (based on lagers). If we consider lager at 80% of the product brewed we can estimate that roughly 3800hl of the capacity can be filled with lager and the remaining 960hl can be utilised for ale.

With 80% of the product in the tanks for approximately 38 days the tank turn time is roughly 9.6 or 10 turns per year. If we can reduce the tank residence time for lagers without compromising the flavour profiles or specifications we can increase the tank utilisation.

For instance, if we can reduce the lager tank residence by 13 days we can increase the tank turns per annum by 5. If we take the largest tank at 400hl the potential increase is 2000hl per annum; multiply this by the average cost of one hl of lager and you can see the ROI in just one tank.

                                            $/hl lager x 2000 = savings

This is assuming that the current tank residences are extended to compensate for the DE filter not being able to handle large solids loads without having to be shutdown & repacked. In other terms the beer needs to stay in the tanks longer to clarify to an acceptable level for filtration.

Even with a reduction of 5 days the potential increase in turns is 1.5 per year for lagers.

For ales the potential is 7 additional turns per year if conditioning is reduced to 14 days from 19 days.

Section 2: Beer Loss During Filtration

Many breweries use a Kieselguhr Filter (“DE”) for their current filtration / beer clarification

process. The move from DE to a centrifuge can provide overall savings of product based on the numbers provided.

The typical beer loss is roughly 1250l (12.5hl) on an average DE filter run taking into account only a single repack of the DE filter if the filter reaches maximum pressure differential.

The ANDRITZ Centrifuge can potentially reduce the losses by 11hl due to the ability to run the majority of the FV bottoms by blending with the racking port, produce minimal loss after the run and 99.9% of the time never have to be restarted during the process.

                                    $beer / hl x 12.5 = current loss (filter)

                                    $beer / hl x   1.5 = loss (Centrifuge) 

Section 3: Time Savings

The ANDRITZ centrifuge is very easy and efficient to start up, operate & CIP / shutdown. The longest wait time is when the centrifuge starts up which still only takes approximately 8 minutes as it comes up to speed. CIP can be completed in 45 minutes with a basic caustic, flush, sanitiser, flush cycle and acid once or twice a week depending on usage and chemical manufacture recommendations.

Based on a typical run taking roughly 10-12 hours the above table shows how we can reduce this by approximately four hours without really doing much. In some cases, this might allow the operators to turn more tanks per day just by lessening the setup and shut down times.

The time reduction can allow for operators to focus or contribute to other areas of the brewery or process more beer / cider per day.

Section 4: Volume Throughput

For instance if you look at a 400hl tank with the DE filter it takes approx. 7.5hrs to empty with significant loss and 3-4hrs of setup / breakdown time. By installing the centrifuge the process time can be potentially reduced (product dependent) to approx. 2.5 to 3hrs with only about 1.2hrs of setup / breakdown time.

                                    11.5 x hour rate = DE cost

                                      4.2 x hour rate = Centrifuge cost

The ability to run multiple tanks is great increased.

Section 5: Oxygen Pickup (DO)

The potential DO pickup is greatly reduced with the centrifuge due to the ability to purge the entire system with the timed “FLUSH” mode on the touchscreen as well as continuous CO2 being applied to the hood & the hydrohermetic seal / product chamber. Some breweries are reporting values as low as 0-5ppb pickup during operation.

Benefits are increased shelf life, better stability and no oxidation in the packaged product.

How to select your Centrifuge

-gear drive vs belt drive;

Gear drive has lower maintenance, cheaper replacement parts & less downtime

– mechanical seal vs internal hydro-hermetic seal;

Mechanical seal have cheaper replacement parts, less service cost, less downtime

– capacity of the machine. Do not go just on the stated capacities as these will vary based on product.

     Check out the bowl volume as large bowl means greater overall capacity

– capacity of the machine

Check out the volume of the solids space. Large space will mean greater capacity, less ejections and therefore less losses

– DO pickup. DO will affect shelf life and quality

Andritz machines have a low DO pickup (applications have shown this as low as 0 – 5   ppb)

– Flexibility when it comes to different beers, ciders or kombuchas. The Andritz machines have a capability across a wide range of applications.

This content was sponsored by Thermaflo. For more information go to thermaflo.co.nz