Metso Insights Blog Mining and metals blog Transforming starch processing operational costs with automatic pressure filters
Industrial filtration
Jan 10, 2022

Transforming starch processing operational costs with automatic pressure filters

The key benefits of pressure filters over centrifuges in starch processing come from increased yield, lower water and power consumption, smaller footprint, lower cake moisture and less steam required for drying. The following blog breaks down the savings achieved with pressure filters versus centrifuges at Hainan Yedao Co Ltd in China using data from real life operations. The plant has now been operating for over 10 years.
Larox® PF Filter
Larox® PF Filter

Our assumptions in the calculations

The equipment for slurry agitation, wet process modification, and heat drying is almost identical in both centrifugal and pressure-filter processes. Heat is transferred by hot oil, which is heated by natural gas. In order to compare the economic benefits of the two different technologies, they were calculated using the same capacity. The assumed plant operating time per day is 20 hours and target moisture content is 13%.

The plant setups for the Larox® PF filter and centrifuge comparison

A complete washing and dewatering cycle can be accomplished in a single Larox® PF filter. In the alternative setup, the same starch throughput would require three disc centrifuge separators (2 × DPF550 and 1 × DPF445) and three horizontal peeler centrifuges (GK1250).

Starch capacity

The first stage of the comparison is to work out equivalent configurations that would deliver the same plant capacity.


Plant Power Required

One critical factor in plant design is the required power. In this comparison we look at the required power infrastructure for the different implementations.


Electricity Consumption

A key component in operational cost is electricity consumption. Energy usage can also be a component in the production of greenhouse gases where sustainably produced electricity is not available. Here we compare the consumption of both solutions.


Starch yield

The starch yield is 2% higher than a centrifuge process due to the volume of wash liquid and the clear filtrate.

Water consumption

In many parts of the world, there is intense pressure on water supplies so sustainable processes use less water or ideally no water at all. In order to reduce water usage, industrial users are charged for consumption so consumption impacts directly operational costs.


Steam drying

The desired end product has a residual moisture level of 13%. Both the cake from the filters and the centrifuges requires drying but the cake from the centrifuges required more drying as it has a higher moisture content




Operations cost

Finally, if we take all these factors together, we can calculate the costs. In this example we use costs in China for this specific case. In many parts of the world electricity, water and labour costs will be higher.


The proven and technically advanced Larox® PF filter offers significant process benefits as well as efficiency and energy savings, and can replace traditional centrifuges in many industrial applications. When applied to a modified starch process it is clear that the Larox® PF filter has low power and water consumption, as well as high productivity, while reducing process waste. Furthermore, the Larox® PF filter can also advance the technology level of the process with its advanced automation. The advantages of the Larox® PF filter becomes even more impressive with higher energy prices.

This blog is based on a paper originally presented in Chinese by Mr. Jin Shuren, Chairman of the Sugar Alcohol Committee (under the China Starch Association). First published at the 8th Symposium of the Modified Starch (Haerbin, 2005), organized by the Modified Starch Specialized Committee of China (under the China Starch Association).

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Industrial filtration