Researchers have developed a way to remove salt from seawater using pressure instead of heat. This process could help reduce energy consumption and emissions at refineries https://ztfilterbag.com/
Bag filters are a common solution for dust collection in cement plants. They provide a finer degree of filtration than basket strainers.
Eaton offers a variety of liquid filter bags that feature fully welded construction and pleated extended surfaces. They also offer the economic benefits of conventional sewn felt bags.
1. Split Frame
Many industrial applications rely on liquid filtration to remove specified trace solids from a process stream. The removal of solids from a process is crucial in upholding product quality and safety, and in maintaining the efficiency of downstream equipment such as pumping systems.
Solids are removed from a liquid by either capturing them on the surface of the filter medium (cake filtration), absorbing them into the depth of the filter medium, or interception between the media and the filtrate fluid itself. Filter bag technology has been used to advance the effectiveness of solid-liquid separation in these applications by increasing the capacity, flexibility, and cost-effectiveness of the process.
A traditional felt or mesh filter bag is constructed with a sewn or welded seam. Sewn bags have mechanical durability but require stitches that can deteriorate the fabric and bore holes into its seams which decreases its particle holding capability. Welded filter bags have stronger seams and more consistent fiber distribution to preserve filtration efficiency.
Composite structures are also used to advance filter bag technology. They consist of a series of laminated layers of graduated nonwoven material. They are used in water filtration as prefilters for membrane and reverse osmosis filters. They are also used in taste and odor adsorption applications, such as in drinking water filters that contain an activated carbon layer.
A split frame enables a greater number of filter bags to fit into a single casing. Its two piece design also makes it easier to handle in larger filter sizes, such as 12,16 and 20 foot long frames that would otherwise be too bulky to fit through an access door. The smaller frame size also reduces plenum height which can lead to lower foundation loads, facilitates installation and assembly and improves aesthetics.
2. All-Welded Design
In addition to reducing fluid contamination, filter bags help protect expensive equipment downstream of the filter. They also improve product purity, increase throughput capacity and limit effluent contamination (minimizing or preventing air and water pollution).
The filter bag’s construction has a significant impact on the operation of the filtration system, especially with regard to the differential pressure generated across the filter. High differential pressure can cause the filter bag to burst, which results in loss of filtration capability and waste disposal costs. This is why it is necessary to support the filter bags with a basket that helps to distribute the weight of the liquid over a large area and reduce the risk of the filters breaking.
SENTINEL® Filter Bags have an all-welded construction that eliminates the possibility of a hole developing in the fabric, which is a common problem with sewn filter bags. This feature, along with the choice of a silicone free material and the use of a bypass-free plastic seal ring provides a highly reliable filter bag with a filtration rating up to 200 microns.
This technology has been used in the construction of several different types of high performance needle felt filter bags. These new filters offer a superior performance compared to traditional felt filter bags, and they can be used in most applications without modification. The new bags are available in two extended life materials, allowing them to be used up to five times longer than conventional felt filter bags.
Needlefelt filters are a depth filter with an all-over fiber structure that captures solid particles as they pass through the filtration media. They have excellent dirt holding capacity and provide a good degree of chemical compatibility. Needlefelts are fabricated with a blend of polypropylene and polyester with the proper combination of fiber diameters, weights and thicknesses to provide an economical depth filter. In order to minimize fiber migration into the filtrate, the fibers are treated with either a glazed or singed surface finish.
3. Pulse Cleaning
A major innovation in baghouse dust removal technology is the patented pulse-jet fabric filter system, which uses low pressure and high volume cleaning air to remove caked-on dust from the inside of bags. It is the most cost-effective and efficient solution to meet today’s stringent particulate emissions limits in industrial applications like power generation, incineration, metal working, steel, food processing, chemical, aggregates and carbon black.
The pulse air is delivered through a special manifold that consists of a series of parallel cylindrical modules with internal distribution and baffling. This design improves dust distribution and decreases high-velocity zones and turbulence. It also allows a larger number of bags to be cleaned in the same time and reduces maintenance time by eliminating blowpipes.
This new filtration technology, called the SimPulse 3C, is more effective than conventional pulse jet filters in humid and aggressive environments because it provides greater energy with low pressure and air volume. This ensures each bag is efficiently cleaned without damaging the filter media. The PLC control allows varying the pulse air volume and duration, which optimizes the amount of energy per bag for each cleaning cycle.
In another example of advanced filtration, scientists at the Lawrence Livermore National Laboratory (LLNL) have created a membrane that separates naphtha and kerosene, the primary components of gasoline and jet fuel, from light crude oil using water instead of heat. This innovative, patent-pending process could significantly reduce emissions and energy consumption at refineries in the future.
Another filtration innovation that is making a difference in the lives of people around the world is a portable, affordable water purification device developed by a non-profit humanitarian organization, PureMadi. The device, which uses simple technology to turn any source of clean, potable water into safe drinking water, is being distributed by the company in developing nations.
4. Internal Distribution & Baffling
In industrial filtration systems, it’s important to have a balanced flow of liquid. To do this, it helps to have a baffle system that directs the liquid flow through a series of spaces. This makes it easier for the liquid to pass through the filter bag and prevents the formation of bubbles and slugs.
The baffles also help to increase the amount of surface area the filter has for the liquid to pass through. This can be particularly helpful when a process needs to run at high flows.
One example of this is the use of clay ceramic filters for desalination. These devices work by forcing water through a ceramic material that has many tiny holes. The holes are big enough to let water molecules through but too small to allow bacteria, viruses and other impurities to pass through. The technology is currently being used for water purification in the mining, pharmaceutical and chemical/pulp industries.
A new technology has been developed for coalescing filtration which increases the efficiency of this type of filtration. Traditionally, coalescing elements have been designed with the compressed gas/air flowing from the inside to outside of the element. This new technology changes the direction of the flow and allows a pleated element design to be used.
Another innovation is a filter for adsorbing oil from liquids. The filter adsorbs the oil and can be easily removed for cleaning. The technology can be used for a variety of applications and is available in multiple micron ratings. The LifeTec depth and membrane filters are designed to be flexible and economical and can be adapted to changing production processes. This can reduce the number of sterilization cycles and increase the quantity of products produced.
5. Internal Inlet
The particle collection efficiency of bag filters is primarily dependent on the inertial and Brownian movements that affect the dust particles. The inertial movement occurs when the dust particles strike the filter fibers placed perpendicular to the flow direction rather than changing with the gas streamlines, resulting in a higher probability of contact between the particles and collecting surfaces. The Brownian movement is caused by the diffusion of submicrometer particles within the gas stream, increasing their likelihood of striking the collected surface. Both effects are enhanced by using a smaller filter fiber diameter than conventional cellulose inlet filters.
The filter design must also be robust and reliable for liquid applications. A new rhomb-shaped liner improves the mechanical and thermal stability of the pleated filter, which enables higher volume flows and an extended life cycle. The improved torsional stiffness and pressure stability also reduce energy consumption for producing the filter pressure. The large filter surface and high retention capacity allow the use of a smaller filter housing, which further cuts costs.
This new lining also makes it possible to use more filter bags for the same system volume, reducing operating costs. It is also easier to clean the filter and maintain process reliability by eliminating a blowpipe requirement, and by allowing operation at lower operating pressures.
This filtration technology opens up economical possibilities for beverage producers, especially breweries and fruit juice manufacturers, to react to growing product diversity while meeting high hygienic standards. The combination of LifeTec depth and membrane filtration in the new sterile air filter program from Donaldson helps companies to increase production reliability and improve profitability.