Flexibulk’s Filter Aid Optimisation Service
Flexibulk prides itself on the filter aid optimisation service, it provides to its customers.

The benefit of this service, which requires a considerable amount of time and the assistance of experienced engineers far outweigh the added value cost, reflected in the price of the filter aids supplied. Long-term, our customers recognise that, when the recommended powders are used, the total cost savings, outweigh the higher per metric tonne price of our filter powders.

It is often a false economy to purchase cheaper filter powders (which do not have the superior filtration qualities of Celatom) from a supplier who has not worked with their customers to ensure the correct grades, in the correct doses are used. Brewery’s who purchase their filter aids by price alone often experience problems such as slow run lengths or high hazes, which create much greater costs down the line.

This case study demonstrates how Flexibulk’s Technical Engineers regularly analyse customers’ filter powder regimes on-site, using tailor-made laboratory equipment, which replicates full-scale filtration systems. These audits are usually undertaken for two reasons:

1. As part of our regular service to our customers to ensure the optimum clarity and throughput is maintained.
   
2. As a result of a request from a customer to solve a particular filtration issue e.g., due to changes in their brewing raw materials, by adjusting the filter aids being used.

This report is an example of a real filtration audit at a Brewery we have called "X" and is divided into three sections.

SECTION 1: Overview of Brewery X’s filtration problem
SECTION 2: The Filtration Audit Report
SECTION 3: Brewery Results Following Implementation of the new Filter Aid Regime.

SECTION ONE
Overview of Brewery X's Filtration Problems

Salient Brewery X Data:

• Brewery output: 1.8 million hl
• Filter Type: Plate & Frame
• Typical run lengths: 2000hl at high gravity

The key issue for Brewery X was that changes in brewing and maturation had increased the level of solids, in some beer qualities, in the maturation vessels and rough buffer tanks. This gave rise to the following major problems:

• Short run-lengths
  
• Shortage of beer for packaging lines.

Flexibulk was invited on site to propose a filter aid system for the site lager beers, i.e. high solids in maturation vessel. This is the report which was sent to Brewery X, following the laboratory trials.

SECTION TWO
Filtration Audit Report

Filtration Audit Report BREWERY X
Conducted Winter 2002

INTRODUCTION
Celatom diatomite FP1SL (permeability 0.8 Darcies) was being used at the Brewery, as a second pre-coat and body-feed during the summer of 2002, to counter occasional high hazes in BBT.
The objective of the filtration audit is to find the optimum filter aid system to:

1. Improve run lengths
2. Have a neutral or beneficial effect on the Bright Beer haze and clarity.

Recent modifications in the powder mixing area permit one diatomite grade to be used as a second pre-coat and a different grade as a body-feed, if required.

METHOD
Laboratory Pressure Test Filter Set-Up
The tests were carried out on the Flexibulk pressure test filter (or ‘bomb’ filter), which enables the examination of various powder systems without disrupting production.

The 10cm2 head was covered with a disc of Cellulose support sheet, which was pre-coated at the equivalent rate as that used on the plant. The body of the filter was charged with three litres of product and body-feed was added at the correct proportion. The filter was pressurised with compressed air.

Data Collection
The filtrate was collected and measured every three minutes, over a twenty-one minute period. Since the pressure was maintained as constant during the test, the flow-rate decreased over time.
If plotted on a linear graph, these results would give a parabola, making comparison between different systems difficult. Results are, therefore, plotted on a log/log graph to give a straight line. This allows for extrapolation and comparison in performance. The steeper the line, the lower is the rate of increase in pressure differential: the higher the line on the vertical axis, the more the throughput over time.
Many tests were carried out, using different filter aids, but only the relevant results are included in this report.

Haze Readings
Site beers are filtered at high gravity. The haze readings throughout this report are expressed at sales gravity.

Current Filter Aid Regime
Site beers are currently filtered on one of two 110m_ filters and the current filter aid regime is detailed in the table below.

Beer Quality’s trialled
One major beer quality was trialled (two separate maturation vessels)

• Beer Quality A: Batch MV1
• Beer Quality A: Batch MV2

Celatom Diatomite Permeability’s
Typical permeability’s for the filter powder grades mentioned are:

CONCLUSION

For the beer qualities tested the following conclusions are drawn:

1. Second Pre-coat and Body-feed
   
   Celatom FP1SL (0.8 Darcies) as second pre-coat and body-feed, removes sufficient solids to give hazes of 0.57/0.53 EBC.
   
   Increasing the permeability of the second pre-coat and body-feed to 1.3 Darcies using Celatom FP1W significantly improves flows through the test filter, however hazes increase by 0.1 EBC.
   
   Celatom FP1SL should therefore be retained as the second pre-coat to give the desired hazes, i.e. filter out haze forming solids passing through the body-feed cake.
   
   The filter run-length (pressure rise) from a powder regime is largely governed by the body-feed. Celatom FP1-W, as a body-feed, is porous enough to significantly improve flow rates but retains enough solids to prevent the surface of the Celatom FP1SL second pre-coat blinding.
   
   
2. First pre-coat
   
   Celatom CP600E Perlite (low floaters) is a very efficient pre-coat grade for the filters.
   

RECOMMENDATIONS
Full scale trials are recommended as follows:
Replace Celatom FP1SL body-feed with Celatom FP1-W (1.3 Darcies max).

SECTION THREE
Brewery Results Following Implementation of New Filter Aid Regime

The brewery ran successful full scale trials and adopted the system recommended and continues to have excellent results:

1. Run-lengths increased from 2000hl to 6000-7000hl, at high gravity
   
2. Typical hazes are good at 0.5 to 0.6 EBC.

The increase in run-lengths, whilst maintaining beer clarity and quality, enabled the filtration department to supply sufficient beer for the packaging department.
In addition, site cost reductions were many, in particular:

1. Decrease in filter down-time
   
2. Decrease in pre-coat usage
   
3. Tank space freed upstream
   
4. Reduced spent cake disposal costs

The case study demonstrates how we can assist our customers in obtaining and maintaining optimum filtration regimes.
Every filtering customer needs to use a filter aid system which is specific to their particular requirements.

If you would like to speak to a member of our sales team to see how we can help improve your filtration and reduce over all costs, please contact us