What is a sintered metal filter?
Advances in Filtration Using Sintered Metal Filters
Advances in Filtration Using Sintered Metal Filters
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Key takeaways:
Sintered metal filters offer high efficiency in particulate removal, with capabilities for backwashing and long service life.
These filters are suitable for high-temperature applications and various industrial uses, including chemical and power generation sectors.
The design and selection of sintered metal filters depend on their particulate holding capacity and the characteristics of the particles being filtered.
They are advantageous for processes requiring high filtration efficiency, durability, and resistance to corrosive environments.
Abstract
Filtration technology utilizing sintered metal media provides excellent performance for separation of particulate matter from either liquid or gas process streams (i.e., liquid/solids and gas/solid separation) in numerous industrial liquid and gas filtration applications. Sintered metal filter media, fabricated from either metal fibers or metal powders into filtration elements, are widely used the in the chemical process, petrochemical and power generation industries. Applications require particulate removal to protect downstream equipment, for product separation, or to meet environmental regulations.
Sintered metal media provide a positive barrier to downstream processes. Sintered metal media have demonstrated high particle efficiency removal, reliable filtration performance, effective backwash capability, and long on-stream service. These filters can provide particulate capture efficiencies of 99.9% or better using either surface or depth media. Operating temperature can be as high as °C, depending on the selection of metal alloy. Along with the filtration efficiency consideration, equally important criteria include corrosion resistance, mechanical strength at service temperature, cake release (blowback cleanability), and long on-stream service life. These issues are critical to achieving successful, cost effective operations.
The life of such filter media (filter operating life) will depend on its particulate holding capacity and corresponding pressure drop. This accumulating cake can be periodically removed using a blowback cycle. The effectiveness of the blowback cycle and filter pressure drop recovery is a critical function of the properties of the accumulating particles in the cake and the filter media. Depth filtration media configured in a polishing filter may be utilized in those applications with light particle loading.
In addition to providing superior filtration in a single pass, clean-in-place backwashable media reducesoperator exposure to process materials and volatile emissions. While applications include high temperature and corrosive environments, any pressure driven filtration process with high operating costs has the potential for improvement using sintered metal filtration technology.
This paper will discuss filter-operating parameters of sintered porous metal media and filtration system design criteria for optimizing performance in a number of chemical process streams.
Introduction
The 21st century brings many economic and environmental challenges to the chemical industry. Major drivers for change include market globalization, demand for improved environmental performance, profitability, productivity and changing workforce requirements. Future competitive advantage in the chemical processing industry will come from patented technology and technical know-how. New economical high yield and high quality processes will characterize much of the industrys production capacity with improved environmental impact and energy efficiency.
A high percentage of the chemical industrys products and processes involve solids (particulate) handling. Filtration technology offers a means of reducing solids through mechanical separation via patented filter design and unique systems operation. Filtration can improve product purity, increase throughput capacity, eliminate effluent contamination (minimizing or preventing air and water pollution) and provide protection to valuable equipment downstream of the filter. Advances in filtration technology include the development of continuous processes to replace old batch process technology. Cost savings include less hazardous waste for disposal and labor savings from new technology. Fully automated filter systems can be integrated into plant process controls.
Solids reduction includes the removal of suspended solids from process effluent waste streams and cleaning solvents. The liquid product recovered is valuable for recycle to another chemical feed stream. Waste minimization includes the reduction of hazardous solids materials for recovery or recycle and solids reduction of non-hazardous materials to landfill. Filtration can reduce wastewater feed stream BOD (Biological Oxygen Demand), COD (Chemical Oxygen Demand), TSS (Total Suspended Solids), and TOC (Total Organic Carbon). These are the main parameters for which current emissions are measured with regard to local and international standards.
Filtration Fundamentals
Knowledge of filtration fundamentals is essential to ensure appropriate design of filter media and the optimum selection of appropriate media and filter design for each filtration application. Two main filtration modes can be considered, i.e., depth filtration and surface filtration. In the case of depth filtration, the particles are captured inside the media; while in surface filtration they are retained, as the term explains, at the surface where subsequently a cake of particles is formed.
Surface filtration is primarily a straining (sieving) mechanism where particles larger than the pore size of the filter media are separated at the upstream surface of the filter; their size prevents them from entering or passing through the pore openings. Subsequent particles accumulate as a cake that increases in thickness as more particle-laden fluid is forced into the filter medium. The cake, due to its potentially finer pore structure, may aid in the separation of finer particles than can be achieved by the filter media. However, the cake must exhibit sufficient porosity to permit continued flow through it as filtration proceeds. Processes can be run under constant flow/increasing pressure or constant pressure/decreasing flow. Because most surface filters are not perfectly smooth or have perfectly uniform pore structure, some depth filtration can take place that will affect the life of the filter.
Depth filtration is mainly used in applications where small particle levels have to be separated such as in the protection of downstream equipment against fouling or erosion, protection of catalysts from poisoning and in product purification. The particles penetrate into the media and are subsequently captured within its multiple layer structure. This multiple layer structure prevents premature blocking of the media and increases the capacity to hold dirt and on-stream lifetime. Because the particles are captured within the depth of the media, off-line cleaning will be required. This off-line cleaning can be accomplished with solvents, ultrasonic vibration, pyrolysis, steam cleaning or water back flushing. In addition, the media may be pleated, a configuration that minimizes housing size and cost.
Understanding of the ability of a filter to remove particles from a gas stream passing through it is key to successful filter design and operation. For fluids with low levels of particulate contamination, filtration by capturing the particles within the depth of a porous media is key to achieving high levels of particle efficiency. The structure of sintered metal provides a tortuous path in which particles are captured. Particles capture continues as a cake of deposited particles is formed on the media surface; however, particles are now captured on previously deposited particles. The life of such filters will depend on its dirt holding capacity and corresponding pressure drop. For fluids with high particle loading, the operative filtration mechanism becomes cake filtration. A particle cake is developed over the filter element, which becomes the filtration layer and causes additional pressure drop. The pressure drop increases as the particle loading increases. Once a terminal pressure is reached during the filtration cycle, the filter element is blown back with clean gas and/or washed to dislodge the filter cake. If the pore size in the filter media is chosen correctly, the pressure drop of the media can be recovered to the initial pressure drop. However, if particles become lodged within the porous media during forward flow, and progressively load the media, the pressure drop may not be completely recovered after the cleaning cycle.
Filtration rates are influenced by the properties of the feed particle concentration, viscosity and temperature. The filter operating mode can be constant pressure, constant flow rate, or both with pressure rising and flow rate dropping while filtering. Filtration cycle will be constrained if solids are fast blinding and allowable pressure has been reached, or for cake filtration, if the volume for cake buildup has been filled, even if the allowable pressure drop has not been reached. Permeability is expressed as flow rate against pressure drop. Permeability is influenced by filter type, fluid temperature and solids loading.
Sintered Powder Metal Media
Sintered metal media are manufactured by pressing metal powder into porous sheet or tubes, followed by high temperature sintering. A scanning electron photomicrograph of a typical sintered powder metal media is shown in Figure 1. The combination of powder size, pressing and sintering operation defines the pore size and distribution, strength and permeability of the porous element. Pore size of sintered metal media is determined using ASTM E-128. The media grade designation is equivalent to the mean flow pore, or average pore size of the filter. Sintered metal media are offered in grades 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 40 and 100. The filtration rating in liquid for media grades 0.2 to 20 is between 1.4 and 35 µm absolute. The filtration rating in gas ranges from 0.1 to 100 µm absolute.
Filter cartridges fabricated from sheet or tubes have an all welded construction. The filter media is designed and engineered with a stable porous matrix, precise bubble point specifications, close thickness tolerances, and uniformity of permeability, which assure reliable filtration performance, effective backwash cleaning and long on-stream service life.
Sintered Metal Fiber Media
Metal fiber filter media consists of very thin (1.5 to 80 μm) metal filaments uniformly laid to form a three-dimensional non-woven structure sintered at the contact points. A scanning electron photomicrograph of a typical sintered metal filter media is shown in Figure 2. These media are explicitly designed for either surface or depth filters. Either single or multi-layered construction are utilized with each layer comprised of potentially different diameter fibers to achieve optimal performance, e.g., pressure drop, filtration efficiency, particle loading capacity, and media strength. The multi-layered material has a graduated design, so the dirt holding capacity is much higher and consequently the life expectancy is longer. The final filter rating is determined by the weight per used layer, the fiber composition of the layer and the combination of several layers. The availability of a high porous structure (up to 85%) offers a very higher permeability and hence a low pressure drop.
The properties of metal fiber filters, fabricated from various metal alloys, for gas filtration applications allow the use in extreme conditions: high temperature, high pressure and corrosive atmospheres. The primary benefits of sintered metal filters are: strength and fracture toughness, high pressure and temperature capabilities, high thermal shock resistance, corrosion resistance, cleanability, all-welded assembly, and long service life.
Fiber metal media have a higher porosity than the powder metal media, thereby resulting in lower pressure drop. For high temperature or corrosive applications, Bekaert has developed fibres in other alloys besides AISI 316L. Inconel® 601 and Fecralloy® are used for high temperatures (up to 560°C and °C respectively) whereas Alloy HR can withstand temperatures up to 600°C and wet corrosive environments.
The inherent toughness of the metal filters provides for continuous, back pulsed operation for extended periods. For high temperature applications, additional criteria such as creep-fatigue interactions, and high temperature corrosion mechanisms need to be addressed. Filters with semi-permanent media are cost effective, since such units lend themselves to minimal downtime, closed and automatic operation with minimal operator intervention, and infrequent maintenance.
The proper selection of filter media with appropriate pore size, strength and corrosion resistance enables long-term filter operation with high efficiency particle retention. The filtration rating in liquid is between 2 and 35 µm absolute. The filtration rating in gas ranges from 0.1 to 10 µm absolute.
Filter Design
The filter design for liquid/solids separation is selected which produces the required filtrate, minimizes backwash or blowdown and maximizes throughput. Three types of filter configurations are described as follows:
1.) Outside-in filtration
Traditional liquid/solids barrier separation occurs on the outer perimeter of a closed-end tubular filter element (LSP). A gas assisted pneumatic hydro-pulse backwash has proven to be the most effective cleaning method for sintered porous metal filters.
2.) Inside-out filtration
Liquid/solid barrier separation occurs on the inside of a closed-end tubular filter element (LSI). LSI backwash modes include: a.) Full shell slurry backwash, b.) Empty shell slurry backwash, c.) Empty shell and empty element wet cake backwash and d.) Empty housing wet cake discharge.
3.) Inside-out Multimode filtration:
Liquid/solids (barrier or crossflow) separation occurs on the inside of open-ended tubular filter element (LSM and LSX). Elements are sealed within two tube sheets, thereby allowing for either top or bottom feed inlet. The LSM filter, with a feed recirculation feature, has proven itself in several continuous loop reactor systems. The downward velocity controls the cake thickness of the catalyst with the lower the velocity resulting in a thicker cake. Filter backwash modes are similar to LSI backwash modes and also includes a bump-and-settle type backwash that allows concentration of solids without draining the filter element or housing. Continuous loop reactor system may not require backwashing.
Scale-ability of the filtration systems allows for accommodating high flow rates and increased solids capacity. Filtration units are suitable for batch or continuous processes. Single housing filter systems are recommended where flow rates allow and flow can be stopped for a few minutes prior to backwash, or if off line periods can be tolerated for maintenance. Two filter dual systems are recommended where continuous flow is required and short periods of off line can be tolerated for maintenance. Three filter systems are recommended for continuous operation even during maintenance periods.
Benchscale and Pilot Testing
A valid method of evaluating filter performance is through bench scale and pilot testing. Filter testing typically begins with a simple disc feasibility test to qualify media and obtain critical filtration characteristics. Successful feasibility studies usually progresses to more involved testing of pilot equipment. Pilot testing helps develop successful commercial separation practices. While bench scale tests produce reliable indication of filter performance, data obtained in pilot scale testing on a process line will show filter operating parameters with normal process variations. Development programs require direct access to suitable equipment over an extended period. Pilot testing of sintered metal backwashable filters can provide the following information:
- Verification of filtrate quality;
- Filter thruput per cycle at various flux rates;
- Rate of rise in pressure drop vs. thruput;
- Backwash volume and resulting solids concentration;
- Scale up data for full scale sizing;
- Accurate cost estimates;
- Demonstrate high product value;
- Reliable operation with high on-line time and low maintenance;
- Demonstrate new technology at a commercial scale.
In addition to verifying filter performance, pilot testing provides the opportunity for the operating engineer to learn to use the equipment and conduct experiments that optimize filter operation for their particular process. Pilot test trials address significant technical questions and problems prior to full-scale commercialization. The outcome of pilot plant operations verify:
- Filtration/reaction studies verified at laboratory and pilot plant scale;
- New technology demonstrated;
- High volume product consistently recovered;
- Product separation and recovery optimized;
- Capacity testing completed;
- Overall operating efficiency.
Media Selection
Feasibility Case Study: Catalyst Solids Removal
A typical approach for feasibility testing and media selection is illustrated in the following test case. The objective was to evaluate the filtering characteristics of a new catalyst to support an existing LSI commercial filter installation. Filtration studies were conducted with a 70-mm disc test filter using both Grades 5 and 10 media to compare filter performance. Catalyst particle size distribution (PSD) was measured using a Horiba LA-910 Laser Scattering Particle Size Distribution Analyzer. The size range (based on volume %) was 0.51 to 60 µm with a mean size of 13.4 µm. SEM microscopy at - X magnification verified particle size distribution as shown in Figure 3. Catalyst slurry was filtered once through at a constant rate using Grades 5 and 10 media housed in the 70-mm disc filter housing shown in Figure 4. A particle size distribution comparison of feed and filtrates (Grade 5) sample is shown in Figure 5. Test results indicate that filtration using Grade 5 media resulted with a lower rate of rise pressure than Grade 10 media as indicated in Figure 6. Filtrate turbidity samples were similar. Filtrate from the Grade 5 media measured 2.9 NTU, while filtrate from Grade 10 media measured 2.3 NTU. The 1/8 inch thick filter cake backwashed effectively from the Grade 5 media surface. Some catalyst remained in the porous structure of the Grade 10 media, indicating that catalyst had blocked some of the surface pores.
Test results indicate that Grade 5 media is better suited for filtration of new catalyst sample using the HyPulse LSI filter configuration. Pilot testing at the commercial facility verified results of feasibility study and resulted in purchase of replacement cartridges for an existing filter vessel.
Commercial Applications
Application 1:
Laboratory disc tests conducted in April indicate suitability of sintered metal filter for catalyst recovery application. Bench scale pilot filter tests were conducted at the customers lab facility to verify filter performance and filtrate quality. In November pilot testing with continuous catalyst filtration using 2% slurry demonstrated consistent flux rates of 0.2 gpm/ft2. A comparison of filter performance from disc testing through pilot testing is listed in Table 1. Axial velocity through the filter controlled cake thickness. The rate or velocity through the filter was optimized in bench scale testing. Optimal filter performance indicated that the filter could operate at pressures < 10 PSI without backwashing. Tests were conducted over about hours with no significant change in operating performance. The project gained approval to move to the final stage.
The objective of pilot test development program was to convert isomerization process from batch to continuous. The first commercial plant was scheduled for operation in . The process was started up in July in accordance with parameters established during the pilot testing. System dynamics experienced during start-up and initial operation exhibited performance similar to the pilot test studies. The filter operated successfully to recover and recycle precious metal catalyst after solvent wash and removal of 10% of the catalyst from the process after each batch. Process liquid is hazardous, however, because the filter system is completely enclosed, solvent could be used to wash and re-slurry catalyst back to the reactor.
The primary (larger) LSM catalyst filter is designed for bulk catalyst filtration and recycle. The filter design offers completely enclosed automated operation with minimal filter cleaning/regeneration. Fresh catalyst is added to each batch. The smaller LSP filter is designed for catalyst removal from the system. After 7 years of operation the filter bundle was replaced during a preventive maintenance schedule. The filtration system continues to operate since its initial installation in .
Application 2:
This catalyst filtration concept was proved in laboratory testing to confirm filter operating parameters and media selection. A development program utilizing pilot testing used a reactor equipped with filtration apparatus capable of separating product from catalyst, whereby the product can be removed from the
reactor while the catalyst is retained, thus permitting the reaction to be run semi-continuously or continuously. Testing utilized the HyPulse® LSM filter design.
By equipping a reactor with a means of maintaining catalyst in the vessel, the reactant can be pumped and the catalyst free product continuously removed. The hydrogenation process stops when the catalyst charge deactivates. The preferred method of filtration was to install a re-circulation loop onto the reactor,
as shown in Figure 7. For an extended batch or continuous process, a larger charge of catalyst is used to ensure sufficiently large commercially viable production quantities. This process allows up to a 50% reduction in total cycle time and an increase in over 65% in the amount of product run as indicated in Table 2.
Application 3:
The first use of sintered metal filters using inside-out (LSI) HyPulse® filtration technology for continuous slurry oil filtration was in . The installation demonstrated the suitability of sintered metal media for high temperature filtration of slurry oil for a carbon fiber development process. The filter operated reliably for many years producing clean oil with solids content of less than 20 ppm and was eventually shut down because of low product demand. Since then, refineries around the world have become aware of the benefits of filtration using sintered metal media for catalyst fines removal in slurry oil service.
Throughout the s numerous LSI filtration systems have been installed for FCC slurry oil filtration. The largest continuous filtration systems utilizes (3) 66 LSI filters as shown in the schematic in Figure 8. Filtration cycle time ranges from 2 to 16 hours operating at 30 & 60 PSI, respectively in the filtration of ppm slurry oil. Extended cycle times were obtained by running two filters simultaneously, but staggered in cycle time, with the third being on stand-by for utilization when one of the other filter units is backwashed. The filter design uses a full shell backwash. Efficiency of the recovered product using two filters on line exceeds 99.8%.
Since there have been many refineries in China have installed LSI filtration systems for catalyst removal in resid fluid catalytic cracking (RFCC) units. A filtration system with (2) 24 LSI filters was installed in a RFCC unit with 1.4 million metric tons (mt) per year capacity and an output of slurry oil of 180 mt/day. The slurry oil has an average 3,000 to 5,000 ppm solids concentration. Cycle time varies from 2 to 8 hours. The filtrate solids content is under 50 ppm. The filter is controlled by local PLC that communicates with refineries distributed control system (DCS) to enable the operator monitor the filtration in the control room. The system is running continuously since then supplying a local company with clean filtrate to produce carbon black.
Application 4:
A process for producing Uranium Dioxide utilizes a HyPulse® gas/solids venturi pulse (GSV) blowback sintered metal filters, as shown in Figure 9, for the recovery of Uranium oxide fines from a process kiln. The sintered metal filters must withstand kiln off-gas stream temperatures of 300°F and be chemically resistant to the gaseous components. The primary risks associated with this conversion are chemical and radiological. The conversion process uses strong acids and alkalis that involve turning uranium oxide into soluble forms, leading to possible inhalation of uranium. In addition, the corrosive chemicals can cause fire or explosion hazards.
Successful field applications and laboratory support provided performance data that resulted in the first commercial filter installation put in service in . The completely enclosed GSV filter operates with 99.999% efficiency with a very low solids load to the filter and infrequent backpulsing. Key operating parameters include controlled approach velocity to the filter, high efficiency, and use of venturi for blowback for continuous operation. Today, one uranium conversion plant continues to operate in the United States using this patented process.
Application 5:
Cleanable sintered metal fibre filters offer an economical solution to processes with increased demand for higher particulate removal efficiency in extreme conditions. The development of metal fiber filter media such as Bekipor® contributed to an increased quality level through higher filter efficiency and a longer onstream
lifetime. Traditional separation systems such as cyclones, ElectroStatic Precipitators (ESP) and disposable filters are losing their appeal. Figure 10 compares emissions efficiency and relative cost of fiber metal compared to ESP and cyclones.
A highly porous structure, which is a characteristic of a sintered metal fibre medium, offers a high permeability and hence low pressure drop, even at high filtration velocities. This results in a low capital expenditure and low running costs. The cleanability for both on line cleaned surface filtration as for off line cleaned depth filtration is excellent.
This application used Bekiflow® HG for removal of alumina and alumina hydroxide dust having a particle size of 50% < 15 μm. Gas temperatures measured 842 °F. Dust concentration before the filter measured 250-800 mg/Nm³. Gas concentration after filtration was less than 30 mg/Nm³. Maximum pressure drop was 15 mbar. Total surface area of the filter was 830 m2. Fiber metal filters offers limited pressure drop and was tested for guaranteed lifetime of 27,000 operating hours. Customer benefits include less filter surface required, smaller bag house therefore less installation place required.
Summary
Sintered metal media provides an effective means of filtering to remove particulate whether they are impurities or valuable by-product of a chemical process stream. These media are ideally suited for more demanding applications involving high temperatures, high pressures, and/or corrosive fluids. Chemical
companies are utilizing filtration to minimize waste products at the source rather than at the end of the line of the production process. Filtration improves product quality and protects downstream equipment in the production of chemical based products. Advances in filtration technology include the development of continuous processes to replace old batch process technology. Liquid/solids filtration using conventional leaf filters is messy and hazardous to clean and require extended re-circulation time to obtain clean product. Traditional gas/solids separation systems such as cyclones, ElectroStatic Precipitators (ESP) and disposable filters are being replaced by sintered fiber metal filtration systems.
Sintered metal filters should be operated within the design parameters to prevent premature blinding of the media due to fluctuations in process operations. Use of flow control assures the filter will not be impacted with a high flow excursion. Filter efficiency increases as the filter cake forms. The cake becomes the filter media and the porous media acts as a septum to retain the filter cake. Filter cakes can be effectively washed in-situ and backwashed from the filter housing. A gas assisted pneumatic hydropulse backwash has proven to be the most effective cleaning method for sintered porous metal filters. Sintered metal filters can be fully automated to eliminate operator exposure and lower labor costs while providing reliable, efficient operation.
Bekiflow and Bekipor are registered trademarks of Bekaert.
Hypulse is a registered trademark of Mott Corporation.
FAQs: Sintered Metal Technology
Q: What is sintered metal?
A: Sintered metal refers to a specialized material made by compacting and forming metal powder under heat and pressure, creating a solid, porous structure ideal for filtration and various industrial applications.
Q: How are sintered metal filters manufactured?
A: Sintered metal filters are produced by compacting metal powder in a mold and then heating it to a temperature below the metals melting point, causing the particles to bond without liquefying.
Q: What are the main advantages of using sintered metal filters?
A: Sintered metal filters offer high durability, excellent temperature and corrosion resistance, and the ability to withstand harsh environments, making them suitable for challenging industrial applications.
Q: In what industries are sintered metal filters commonly used?
A: Sintered metal filters are widely used across various industries, including pharmaceuticals, food and beverage, chemical processing, and aerospace, for their efficiency in removing particulates from gases and liquids.
Full Guide About What is Sintered Metal Filter ?
For Sintered Metal, What is that ?
What is Sintered Filter Working Principle ?
Short to say, Because of the stable porous frame, sintered metal filters are one of the better filtration elements
nowadays. Also, the metal materials' high temperature, high pressure, and corrosion resistance can help you
easily complete the filtering task in a harsher environment, Separating and filtering out excess impurities
you don't need or helping you extract higher purity gases or liquids for your project.
Maybe You Should not hear this word much in your daily life.
But nowadays, sintered metal to use more and more in various industries, the sintered metal has started to become
the key technology in some manufacturing.
Then What Exactly is a Sintered Metal
Actually, it is a branch of the powder metallurgy industry, in short, is the 316L stainless steel powder through the mold
shaping, high temperature sintering into the shape and function of a process that we need.
Then, Firstly, sintered. What is sintered? Sintering is the process of compacting and forming a solid mass of material
by heat or pressure without melting it to the point of liquefaction. Sintering is part of a manufacturing process used
with metals, ceramics, plastics, and other materials. Wikipedia
As Wikipedia describes, many kinds of materials can be sintered, and different materials sintered products have
different applications. Then here we like to talk more details about sintered metal.
History of Sintering Metal
1. Who Inventions the sintering and started to use the sintered products?
According to historical records, the sintering process emerged during the second industrial revolution 18th century
in Sweden and Denmark. Sintered iron was found during the smelting process in coal mines. But till , people
started to use the sintered metal to the filtering oil. And for , the first used HyPulse® filtration technology for
continuous slurry oil filtration.
It marks the beginning of sintered metal filters.
The setup demonstrated the suitability of sintered metal media for heat filtering of slurry oil for a carbon fiber
growth process.
The filter ran accurately for years creating clean oil with solids material of less than 20 ppm solids and was
eventually closed down due to low item demand. Since then, refineries worldwide have become aware of the
advantages of filtration using sintered metal media for catalyst fines elimination in slurry oil solutions.
Since , many refineries in China have mounted LSI purification systems for stimulant elimination in resid
fluid catalytic fracturing (RFCC) systems. Set up A filtration system with (2) 24" LSI filters was set up in an RFCC
system with 1.4 million statistics bunches (mt) each year capability and a result of slurry oil of 180 mt/day. The
slurry oil has an ordinary 3,000 to 5,000 ppm solids focus. Cycle time varies from 2 to 8 hours. The filtrate solids
material is under 50 ppm. The filter is controlled by a local PLC that communicates with the refinery distributed
control system (DCS) to enable the driver to monitor the purification in the control space. The system has
constantly been running, providing a local business with clean filtrate to generate carbon black. So as the
application, the sintered Metal, It is mainly used to filter or separate solids or magazines from liquids or
gases for the purpose of purification.
2. So What is Sintered Metal Filter ?
A simple definition of sintered metal filter: It is a metal filter that uses metal powder particles of the same
particle size to be shaped by a stamping, high-temperature sintering process. Sintering is the process of
metallurgy using powder-sized bodies of different metals and alloys after stamping.
Metallurgy occurs by diffusion at temperatures below the melting point of high-temperature furnaces.
The metals and alloys commonly used today include aluminum, copper, nickel, bronze, stainless steel,
and titanium.
There are different processes you can use to form the powder. They include grinding, atomization,
and chemical decomposition.
3. What the Sintering Metal Filter Manufacturing Process
Then, so here, we like to check the process detail of Metal filter manufacturing. if interested, please check below:
1.) What is Sintering, Why Use Sintering?
Simple definition sintering is metal powder is bonded together by high temperature and other methods into
the desired module. In the micron range, there is no physical limitation between the metal powder particles,
which is why we can control the pore distance
through the production process.
The porous cartridge of the sintering process provides the stable shape of the metal and provides
the material with the performance of robust filtration.
2.) 3-Main Steps of Sintered Metal Filter Manufacturing
A: First Step is To Get the Power Metal.
The metal powder, You can obtain metal powders by grinding, atomization, or chemical decomposition.
You can combine one metal powder with another metal to form an alloy during the fabrication process,
or you can use only one powder. The advantage of sintering is that it does not change the physical
properties of the metal material. The process is so simple that the metal elements are not altered.
B: Stamping
The second step is to pour the metal powder into a pre-prepared mold in which you can shape the filter.
The filter assembly is formed at room temperature and under stamping. The amount of pressure applied
depends on the metal you are using, as different metals have different elasticity.
After a high-pressure impact, the metal powder is compacted in the mold to form a solid filter. After the
high-pressure impact procedure, you can place the prepared metal filter in a high-temperature furnace.
C: High-temperature Sintering
In the sintering process, the metal particles are fused to form a single unit without reaching the melting point.
This monolith is as strong, rigid, and porous a filter as the metal.
You can control the porosity of the filter by the process according to the flow level of the air or liquid to be filtered.
The sintered media grade designation is equivalent to the mean flow pore, or average pore size of the filter.
Sintered metal media are offered in grades 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 40 and 100. The filtration rating in
liquid for media grades 0.2 to 20 is between 1.4 and 35 µm absolute. The filtration rating in gas ranges
from 0.1 to 100 µm absolute.
4. Why to Use Metal Sintering to Make Filter?
This is a good question, why use metal to make a filter?
The answer is simple, and although there are many reasons, the cost is the most important.
Why Cost ?
Yes, the sintered metal has a stable structure and can be reused, clean, and used many times.
And also, different metals have stable physical and chemical properties and are not easily damaged.
It is why more and more Sintered Filters are used in different industries.
5. What are the Material Choices for Sintered Filters?
With the continuous progress of powder metallurgy technology, there are more choices of
materials for sintered metal filters,
You can choose from many other metals and alloys to meet special requirements of higher
temperature and pressure, corrosion resistance etc , Main metal materials such as :
-
Stainless Steel Filter ; 316L, 304L, 310, 347 and 430
-
Bronze
-
Inconel® 600, 625 and 690
-
Nickel200 and Monel® 400 (70 Ni-30 Cu)
-
Titanium
-
Alloys
More and more metal will be used in the future.
6.
8
-Main Advantages of Sintered Metal Filter
1. ) Corrosion resistance
Most metals are inherently resistant to corrosion, such as sulfides, hydrides, oxidation, etc.
2. ) More effective removal of contaminants
Adjusting the porosity of the cartridge to the fluid means you can achieve the perfect
filtration you want and get a contaminant-free fluid. Also, since the filter does not corrode,
the filter's reaction does not result in the presence of contaminants in the fluid.
3. ) High Thermal Shock
During the manufacturing process, high heat is generated, and the physical properties of
these metals help absorb the filter's great thermal shock. As a result, you can use these
filters in a wide range of applications depending on the thermal range of the application.
If you want to learn more, please visit our website Sintered Metal Filter for Water Treatment.
Great thermal shock also ensures effective fluid filtration without having to worry about
the heat of the application.
4) Reasonable Pressure Drop
A sintered metal filter can maintain fluid pressure in your application, thus ensuring
maximum operation.
A slight pressure drop can harm your application.
5. ) Temperature and Pressure Resistance
You can use this filter in applications with high temperatures and pressures without
worrying about your filter element.
Using sintered metal filters in the production process of chemical reactions and gas
treatment plants ensures you get the best filtration results.
6. ) Tough and Resistant to Breakage
Another benefit of using a sintered metal filter is that it is strong and resistant to
fracture.
During the manufacturing process, the bonding of metals occurs at temperatures well
below the melting point.
The resulting product is a tough sintered metal filter that can withstand various
harsh environments.
For example, you can use it in applications requiring friction without fear of breakage.
7.) Fine Tolerances
Fine tolerances mean that your sintered metal filter can filter your fluid without reacting.
Once your filtration is complete, the sintered metal filter will retain its physical properties.
However, it would help if you made sure that the metal you choose for your filter will not
react with the fluid you are filtering
8.) A range of Geometric Possibilities
Sintered cartridges allow you to enjoy a wide range of geometric options. You can achieve
this while inserting the powder into the dye during manufacturing.
The mold is the one that should design your filter.
Therefore, you are free to operate the design according to your specifications.
For example, if your application requires a small filter, you can easily manipulate the design
to obtain a smaller
sintered metal filter. Likewise, if your application has a distinctive design, you can easily
manipulate the design in the mold during manufacturing.
7. How Sintered Metal Filters Work?
This problem can also be said to be the working principle of sintered metal filters. Many people think
that this question is very difficult to answer, and it is not. You may be surprised by this, but maybe you
won't be after reading my explanation.
Sintered metal filters are very useful filters. The collection of contaminants occurs on the surface of
the fluid; when the fluid passes through the metal filter, the large particles and contaminants will be
left on one side of the cartridge, but when choosing an effective filtration level for your fluid, you
need to make sure that it can even filter the requirements.
These Requirements Include
1. Contaminant Retention Backwash Capability
2. Pressure Drop
For pressure drop, you need to consider several factors.
These factors include
A Fluid viscosity, fluid velocity as it flows through the filter element, and contaminant characteristics.
B Contaminant characteristics include particle shape, density, and size.
If the contaminant is hard and regular in shape, forming a dense cake, then surface filtration is appropriate.
The Effectiveness of Sintered Metal Filtration Depends on
1. the increased pressure drops to the point where the absolute pressure is reached.
2. the constant flow of the fluid.
You can achieve end conditions by thickening contaminants that increase to the point where the fluid pressure drops.
This pressure drops continuously until the maximum drop for a given viscosity and flow rate requirement is reached.
Another important issue is the back washing of the filter, which is performed by pressurizing the gas to the screen and rapidly
opening the backwash discharge valve as the backwash occurs.
A high reverse instantaneous pressure differential is generated. It effectively removes contaminants from the filter
element surface. The reverse flow of clean fluid through the filter element removes contaminants and directs them
out of the filter.
The steady rise in pressure drop rate indicates a consistent and uniform distribution of contaminant size. To
achieve consistent performance, you must ensure that the filter element's pressure drop is stable. If the temperature
of the fluid changes, it affects the viscosity of the fluid. In this case, the pressure drop across the filter element will
increase and not achieve the filtration effect.
Therefore, you need to maintain the working temperature of the filter during the filtration process and
ensure the temperature of the fluid and the pressure. When cleaning the filter, you need to follow the
correct back washing procedure.
How the Sintered Metal Filters Works ?
You can easy to understand when you check the follow Working principle diagram
As follow is main 8-Kinds of The working principle of metal filtration, hope it will be helpful for you to
understand more for how sintered metal Filter can help for fiteration liquit, gas and voice.
1.) Liquid & Gas Filtration/Separation
Sintered Metal filters can reduce or completely remove particulate matter from a gas or liquid medium.
Particulate matter can include but is not limited to suspended particles (sediment, metal chips, salt, etc.),
algae, bacteria, fungi spores, and unwanted chemical/biological contaminants. Metal filter pore sizes
can make to be range from 0.2 µm 250 µm.
Some of Sparging Applications :
Soda Carbonization
Beer Carbonization
Oxygen Stripping of Edible Oils
Sparging is the introduction of a gas into a liquid. It is used to either remove an unwanted dissolved gas
(oxygen stripping) or a dissolved volatile liquid. It can also use to introduce a gas into a liquid (carbonization).
Traditional sparging created bubbles with a diameter of 6 mm. PM filter sparging allows for an even smaller
bubble diameter, thus increasing the surface area of the bubbles creating a more efficient sparging
application by decreasing process time.
3.) Breather Vents
Sintered metal filters are also used as breather vents in cylinders, gearboxes, manifolds, hydraulic systems,
reservoirs, and other systems. Breather vents allow pressure equalization and air/gas in and out of a system
while blocking particulate matter from entering the system. Metal filters can be back washed to remove particulate
matter, giving them a longer lifespan as a breather vent than other filter media.
4.) Sensor Protection
Sintered Metal Filters can also protect electronic components as a cover, such as thermometers,
various sensors, key components of medical systems, and other sensitive products from water,
liquids, sediment, dust, and pressure fluctuation.
5.) Flow Control ( Throttling / Dampening )
A special sintered filter can control the flow within an air, gas, vacuum, and fluid flow system. The
filter's uniform pore sizes allow for consistent, repeatable flow regulation and protect valves, sensors,
and anything else downstream in the system from contaminants. Flow control is used in such
applications as pneumatic timers, gas supply control elements, and time delay elements in
automotive applications.
6.) Air Exhaust Silencers
Sintered filters can also be welded or sinter-bonded to any required fitting, allowing them to work as an
exhaust silencer. The filter cannot only protect solenoids and manifolds from contaminants inside the
system but also minimizes the noise level of exhaust from the system. The air exhaust silencer filters
also lower the air blowing out from the system, which minimizes contaminants wafting, Protecting
the environment.
7.) Flow / Pressure Equalization
Sintered filters can equalize and control a system's flow rate and pressure. Equalization protects
systems against a surge of liquid and creates a uniform flow as the gas or liquid moves across
the uniform pores.
8. What Are Sintered Filters Used For ?
For this question, Actually more people will ask What are the application of sintered metal Filters?
After such a complicated process, where will the sintered metal filter cartridges be used?
The truth is that you can find these filters in various industries.
Common applications include the following.
1) Chemical processing
You can find sintered metal filters in the chemical solvent and gas processing industries, including the
nuclear industry. The corrosion, high temperature, and non-reaction to chemicals make sintered metal
filters a distinct advantage in
the chemical processing industry.
2 ) Petroleum refining
For petroleum refining, to effectively filter different fuels
We need to use different metal filters according to the degree level to complete the filtration of the
specific fuel from the feed stock. Yes, sintered metal filters can help you achieve this goal.
Because metal filters do not react chemically with the fuel.
Therefore, the specific fuel will be free of any contaminants after filtering.
In addition, you can use it at temperatures up to 700°, which is common in petroleum refining.
3.) Power generation
Hydroelectric power generation requires the continuous operation of a turbine. Still, the
environment in which the turbine operates often requires filtration to achieve a body of water in
which the turbine is free of any impurities.
If the turbine is overloaded with impurities, it will wind up and prevent the turbine from rotating,
and then the turbine will not generate electricity. You can use sintered metal filters to ensure
effective and efficient power generation.
These filters are used to generate electricity by filtering water from the turbine.
Because they are not eroded by water, the turbine will work for a long time.
4.) Natural gas production
Another important area of application for sintered metal filters is gas production.
Sintered metal filters are very useful in gas production because they do not react with the gas,
and you can use them in different environments.
5.) Food and beverage
Metal filters extract essential nutrients and juices in the food and beverage processing industry.
Metal filters effectively filter and prevent these nutrients from being washed away during processing.
The advantage of the same metal filters is that they do not react with specific foods or beverages.
When using these filters guarantees the quality of your production process.
9. What kind of
Sintered Metal Filters
HENGKO Can Supply ?
HENGKO main supply 316L, 316 and bronze sintered metal filers. main shape such as follow list:
etc., any shape your project requires.
Sure, we supply O.E.M Service
1. O.E.M Shape : Disc, Cup, Tube, Plate ect
2. Customize Size, Height, Wide, OD, ID
3. Customized Pore Size / Apertures from 0.1μm - 120μm
4. Customize different Thickness
5. Mono-layer, Multi-layer, Mixed Materials
6. Integrated design with 304 stainless steel housing
For Your More O.E.M details, please contact HENGKO Today !
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