How to Better Dry Filter Press Cake?

Getting your filter press cake as dry as possible is crucial for efficient processing and reduced costs. In this complete guide, as a professional filter press manufacturer, I’ll show you several methods to significantly reduce moisture content so you can improve cake dryness.

Why Drier Filter Press Cake Matters

When you send wet filter cake to the next stage, excess moisture causes a host of problems. Here are some of the biggest issues with not properly drying the cake:

Higher Energy Costs – Wet cake requires far more energy to process. For example, sending cake with 50% moisture to a dryer compared to 30% moisture requires over 40% more energy.

Slower Processing – Due to the extra moisture, processing wet cake takes more time. This slows down the entire operation.

Material Loss – Some wet cake can stick to equipment and be lost. Drier cake releases easily so less raw material is wasted.

Storage Issues – Wet cake takes up more volume and can be unstable for storage. Dry cake is smaller and stacks neatly.

Transportation Costs – Shipping wet cake costs more since you pay for the extra weight. It also may require special containers.

Clearly, drier filter cake provides tremendous advantages. Next I’ll explain multiple methods to reduce moisture so you can reap these benefits.

How to Better Dry Filter Press Cake

Optimizing Operating Parameters

One of the easiest ways to enhance filter press cake dryness is to optimize the operating parameters. This requires no equipment changes – just adjustments to your current process.

Increase Pressure

Higher pressure forces more liquid out of the cake during the filtration cycle. Most filter presses are designed for pressures between 100-500 PSI.

Boost your pressure towards the higher end of the range. Be aware that extremely high pressures can damage plates.

Extend Filtration Time

The longer cake remains compressed under pressure, the more moisture is removed. Filtration times often range from 30 minutes to 2 hours.

Test extending your normal cycle in 15-30 minute increments to find the optimum time for your application. Just be wary of diminishing returns after a certain point.

Lower Feed Flow Rate

Reducing the flow rate of slurry into the filter press allows more time for liquid to migrate out of the cake.

Try cutting your normal feed rate in half. This gentler filling better facilitates dewatering without harming wash quality.

Employing Auxiliary Measures

Beyond adjusting operating parameters, auxiliary techniques can further enhance cake dryness:

Membrane Squeeze

Membrane plates utilize inflatable diaphragms that compress the cake when activated. This additional squeeze force liberates significantly more liquid.

Be aware that membrane squeeze works best for compressible cakes. Adjust pressure so plates don’t rupture.

Cake Blowing

Cake blowing involves shooting compressed air through formed cakes after the filtration cycle finishes. This air flow effectively “blow drys” the cake by displacing moisture.

Work air supply equipment into your existing system for automated blow drying. Humidity measurement before and after will indicate efficacy.

Preconditioning Agents

Certain chemicals alter slurry characteristics to improve dewatering properties. Common examples include:

• Flocculants – Clump fine particles so water flows easily
• Coagulants – Bind molecules so cakes filter faster
• Surfactants – Change surface chemistry to repel water

Dose these ahead of the filter press to precondition the slurry for drier cake. Overuse can make cloth cleaning difficult.

Cloth Treatment

Special chemical coatings applied to filter cloths modify surface properties to reduce sticking and cake moisture.

Cloth impregnation typically takes place during off-hours. Reapply after routine cloth cleaning for maintained effects.

Chamber Modifications

Altering the internal channels and ports enables better liquid flow out while retaining solids. This positively influences residual moisture.

Upgrading older model plates to current chamber configurations greatly enhances dewatering.

Key Takeaways on Drying Filter Press Cake

To wrap up, here are the essential points to remember about getting your filter cake as dry as realistically possible:

• Significant cost, productivity and efficiency benefits arise from dryer cake
• Adjust operating parameters like pressure, time, and feed rate to drive out more liquid
• Auxiliary techniques such as membrane squeeze and cake blowing further reduce moisture
• Preconditioning additives and filter cloth treatments aid dewatering
• Up-to-date chamber designs optimize flow for lower cake moisture

Implementing even a few of these suggestions will lead to major improvements in cake dryness. Let me know in the comments if you have any other tips I missed!