How does Backwash Efficiency Affect Your Catalyst Bed Protection Filtration System?

Filtration systems are generally regenerated through a backwash cleaning cycle. The primary factors effecting backwash efficiency are • Available pressure differential • Backwash flow • Filter media characteristics  

Available Pressure Differential:  During backwashing, the backwash differential pressure (between the backwash source and drain) should ideally be three to five times greater than the differential pressure across the dirty media.  In a feedstock filter, the maximum dirty differential pressure should not exceed 15 PSID, meaning the backwash liquid should be delivered at 45 – 75 PSID to maximize the cleaning efficiency.

Backwash Flow:
A sufficient flow rate of backwash liquid will also be required to regenerate the filtering media. The required flow rate will be primarily dependent upon the type of media selected. Sufficient backwash flow along with sufficient backwash pressure will lead to hydro-shock cleaning effect and completely regenerate the media to its clean differential pressure.

Filter Media Characteristics:
The final component of filter regeneration is the media characteristics. By their very design, slotted wedge wire and woven wire mesh allow particles to be captured on the surface of the media, providing optimum particle release and media regeneration.  Sintered metal is multi-layered and can offer higher per-cake efficiencies, but can be difficult to regenerate.  This leads to shorter run times and increased downtime.

In summary, feedstock filtration is an important aspect in efficiently refinery operation.  Protecting catalyst beds from particulate contamination prevents bed plugging and increases catalyst life. Several factors affect filtration system efficiency and should be carefully considered when selecting a feedstock filtration system.

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Why Cleanable Media for Industrial Filter Processes is More Environmentally Friendly

Due to the new environmental regulations — and the costs associated with waste disposal — the manner in which industries filter to either recycle or eliminate filtration waste is constantly changing.

Selecting filtration equipment is the combined result of many considerations.

In addition to removing undesirable material from a liquid stream, the filtration method selected must also satisfy other requirement.

Installed costs must be weighed against operating costs. Waste disposal costs must be considered. Is continuous flow a requirement of the application, or can the filtration equipment be operated intermittently? Is worker exposure to the process liquid during filter cleaning or replacement a problem?

These and other factors must be weighed when choosing the right filtration method for a particular application.

Today, more than ever, self-cleaning filters (cleanable media) is the better methodology — and many times the right thing to do — for many reasons.

With cleanable systems, you enhance employee safety by minimizing worker and workplace exposure to process liquids.

You minimize or eliminate the unlimited cost and inconvenience of media replacement.

You minimize or eliminate the never-ending and ever-rising cost and hassle of media disposal.

You drastically reduce the labor costs to source, purchase, inventory, transport, change, and dispose of replacement media.

You increase the quality and consistence of filter performance and productivity.

To help reduce the confusion when you are evaluating different filtration methods/systems, I have compiled a list of questions you may want to consider:


Factors to Consider: When selecting a filter for a particular application, the following criteria should be considered.

1. How large is the process volume? What is the flow rate?

2. Is it a continuous or batch process?

3. What are the material characteristics of the solids being removed? How large are the particles? Is the material hazardous? Can the material being removed be recycled back into the process stream at another point?

4. What are the waste disposal costs? How often do bags or cartridges need to be replaced? Can the waste volume be reduced or eliminated by switching to a different filtration method?

5. What are the labor and downtime costs for filter or cartridge replacement? Can downtime be reduced or eliminated by switching to a different filtration method?

— Eaton Filtration

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