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One Minute Filtrationsm Articles

The One Minute Filtrationsm Article is a feature of the AFS monthy eNewsletter.  Each month a new short information sheet is produced on filtration and separations.  To receive the AFS monthly eNewsletter just sign-in to the form above.

Gas Monetization: How are we doing? (Part 1 of 2)

The hydraulic fracturing (“fracking”) technology at the center of the North American energy revolution qualifies as a “disruptive” technology.  The United States was constructing plants to import LNG as late as 2008. Now, gas consuming markets in the United States are being challenged to consume the natural gas that the energy industry can produce domestically, an activity called “Gas Monetization.” The activities are concentrated in four application areas:
1.    Liquefied natural gas (LNG) for export
2.    Electrical power generation
3.    Motor fuel for transportation
4.    Chemical production


Electrostatic Nonwoven Polymer Filters for Nanoscale Particulate Capture

Growing air pollution is presently a large concern all over the planet. Rapid industrialization, vehicle exhaust, urbanization are considered as most effective primary man made contamination sources. Needs for highly effective air filters for capturing Ultrafine and Nanometer scale particles from air streams are growing very rapidly. The use of metal wires maintained at high electrical potentials (Cottrell precipitators) as air filters are well known, but use of electrically charged polymer fibers (electret fibers) is problematical. The term Electret is defined as a permanently polarized electrically insulating material with long-lived internal and/or external quasi-permanent surface charge[1]. The electrostatic forces provide a mechanism to attract particles from airstreams, in addition to classical filtration mechanisms of inertial impaction, interception and Brownian diffusion whereas other mechanisms like gravity and sieving effect have negligible effect in nanoscale filtration[2]. The electret property of synthetic polymers has led to several revolutionary inventions such as piezo-electric transducers, audio microphones, radiation sensors, and particulate aerosol filter media. Electrospun nonwoven fibrous membranes possess significantly larger surface to volume ratios, hence they perform much better in terms of retaining charge density and stability over time. Thus electret filter media are widely used as respiratory filters because of their high capture efficiency but with low breathing resistance.


The Recovery of Hydrocarbon Aerosols from Natural Gas Streams

Liquid/Air Separations in the Oil & Gas Industry - The Recovery of Hydrocarbon Aerosols from Natural Gas Streams

Removing liquids and solids from a gas stream is very important in refining and gas processing applications. Effective removal of these contaminants can prevent costly problems and downtime with downstream equipment like compressors, turbines, and burners. In addition, hydrocarbons and solid contaminants can induce foaming in an amine contactor tower and can contribute to premature catalyst change-outs in catalytic processes. In compressors that use oil to lubricate cylinders, the lube oil often gets into the discharge gas causing contamination downstream.


Simulation and the Future of Filter Design

(Part 1 of 5)

The vision of many filter media makers and filter manufacturers is to remain competitive by fulfilling their client’s requirements of low pressure drop, high filter efficiency, and long filter lifetime, while incorporating innovative filter materials quickly and at low cost. Nothing would be better than to hone in on a few promising designs and restrict costly lab tests to these few designs.


Removal of Hydrocarbon Droplets from Produced Water Streams

Liquid/Liquid Separations in the Oil & Gas Industry - The Removal of Hydrocarbon Droplets from Produced Water Streams

In the Oil and Gas Industry, the efficient removal of hydrocarbons from produced water streams is essential. While it is well known that two immiscible, or insoluble, liquids will separate naturally if given enough time, this process may take days.  This article discusses the settling law governing the separation of immiscible liquids and the role of coalescing devices.


Winding Pattern: An Effective Tool to Improve Performance of Wound Filters

Wound filters are mostly used as pre-filters nevertheless they can be considered as an essential part of any water purification system and can be produced using filter winders. These winders may be operating on any suitable winding mode; controlled mechanically or electronically. Despite mechanical system being cheaper the electronically controlled system on such filter winder can provide more flexibility.


A Brief Discussion of Wettability and its Effect on Filter Design

A common perception of filtration is its application to separation of rigid, solid, and non-deforming particles from a fluid (gas or liquid) stream.  Many, perhaps most, applications are much more complicated than this simplified view.  Gel-like particles are soft and deformable.  Many process separations involve liquid droplets dispersed in a gas phase or immiscible liquid drops and gas bubbles in a continuous liquid phase.  Some processes contain complex mixtures of gases, liquids, gels, and solid particles.  Perhaps some of the most difficult phase separations involve produced water. Produced water is a term applied to the aqueous phase that is drawn out of the ground during oil and gas well drilling and production.  Produced water contains miscible organics, immiscible oil drops, condensed gases (under high pressure), gaseous bubbles, sands, clays, and a wide range of chemicals.  Produced water is further complicated by its transient nature.


Is a "Pinhole" a Serious Problem in an Air Filter Media?

by Peter P. Tsai
The University of Tennessee

"Pinhole" can easily happen to a filter media during manufacturing or converting processes. Microglass fiber media are fragile. A shot making a pinhole or pinholes in the fabrics can frequently occur in electrospinning and in meltblowing (MB) processes. How seriously will a pinhole affect the filtration efficiency (FE) of a filter media?


Dust and Filtration in Space

space-filterDid you know that filtration is alive and essential in space? Air filtration, while ubiquitous on earth, is essential for the confined and closed spaces found in space habitats. The required air cleaning and filtration systems not only need to remove a broad size range of particles, such as skin flakes, hair and clothing fibers, and other substances from food and hygiene operations, but they must also remove any extraterrestrial planetary dust tracked into the habitat by the crew returning from exploration, as well as debris from operating machinery and equipment inside the habitat – all without make-up air or venting.


Gas Monetization: How are we doing? (Part 2 of 2)

This article is Part 2 of a series on Gas Monetization. Gas Monetization refers to activities related to domestic natural gas production. In Part 1, liquefied natural gas (LNG) for export was discussed.  In Part 2, we will explore activities in the remaining three application areas:
1.    Electrical power generation
2.    Motor fuel for transportation
3.    Chemical production


Activated Carbon Filter Cartridges Remove Impurities

Activated carbon has long been used to remove chlorine and other impurities from water and other liquids.  Activated carbon is available in various cartridge forms to fit standard industrial housings. An example of the effective use of carbon cartridges is the food processor who produces bagged salads using process water to rinse lettuce and vegetables before packaging.