Tube Settlers vs. Plate Settlers: Comparing Lamella Technologies

Tube Settlers vs. Plate Settlers: Comparing Lamella Technologies
Posted by kkkoo6ko on 2021/08/26
Tube Settlers vs. Plate Settlers: Comparing Lamella Technologies

    Tube Settlers vs. Plate Settlers: Comparing Lamella Technologies

    The sedimentation process in both water and wastewater treatment is a physical process which relies on gravity to settle

and remove suspended solids. Advanced solids settling processes typically utilize lamella, commonly referred to as tube

settlers or plate settlers, to reduce the vertical distance solids particles must fall until hitting a “settling surface”.

Higher flow rates, better effluent quality, and more compact sedimentation basins can all be achieved with both types of

lamella sedimentation equipment. Although both operate on the same principles of solids settling and can be used as basis of

design in many cases, there are several notable differences between the two technologies.


    Characteristics of Tube Settlers and Plate Settlers


    Tube settlers utilize multiple adjacent tubular channels that are sloped at a nominal 60° angle and combine to form an

increased effective settling area. The size and shape of the tubular channels vary by

manufacturer
. Brentwood’s tube settler design features a

trapezoidal shape created by thermoforming PVC sheets. You can learn more about our design process by reading our

Thermoformed vs. Extruded Tube Settlers blog.


    In contrast, plate settlers use a series of inclined plates, typically constructed of steel, which are spaced two to

three inches apart from each other on a 55° to 60° angle to form an increased effective settling area. As a result of these

design differences, typical design parameters for these two types differ.



    Comparing Design Parameters


    It is important to note that there is a difference in application rate (flow rate/coverage area, expressed in gpm/ft2)

between tube settlers and plate settlers as a result of different effective settling area terms used, despite settling

principles being similar for the two technologies. To provide a more direct comparison, the application rates of tube

settlers can be converted to an equivalent “plate” application rate by taking into account the projected surface area of

tubes:


    As illustrated in the above table, the equivalent maximum “plate” application rates of Brentwood tube settlers are in

the same range as a generic plate settler, which has an average application rate of 0.30. IFR6041 tube settlers are the most

comparable to plate settlers in regard to coverage area because settler length is similar. However, Brentwood’s other tube

settler modules are capable of treating required flow just as effectively with appropriate coverage area. Tube settlers also

eliminate cross-flow and eddy currents, which makes flow hydraulics more stable and efficient.


    In addition to varying design approaches, there are other advantages and disadvantages to consider when comparing tube

settlers or plate settlers for your application:


    Tube Settlers


    Advantages:


            Lightweight PVC results in easy installation and does not require heavy lifting equipment
       
   
   
       
            Lower capital cost due to materials of construction
       
   
   
       
            Applicable in shallow tanks with underflow velocity concerns
       
   
   
       
            Twenty to twenty-five year service life, provided proper maintenance is performed
       
   
   
       
            Only PVC tube settlers are replaced at the end of their useful life typically supporting structures and effluent

troughs can remain
       
   
   
       
            Tube settlers are strong enough to walk on top of for proper maintenance

       
            Highly customizable to accommodate varying basin configurations

    Disadvantages:


       
            Maximum module vertical height is 41 inches, resulting in a maximum application rate of 3.5 gpm/ft2
 
       
            PVC must be protected from extensive UV exposure. Brentwood tube settlers do contain UV inhibitors. AccuGrid

protective surface grating is also available for additional UV protection.
       
   


    Plate Settlers


    Advantages:


   
       
            Less limitation on depth
       
   
   
       
            Longer lifespan due to material of construction


    Disadvantages:


   
       
            Two to three times higher capital cost
       
   
   
       
            Higher installation cost due to required heavy lifting equipment
       
   
   
       
            Deeper basin requirements to accommodate underflow velocities
       
   
   
       
            Risk of corrosion in certain environments (certain industrial wastewater applications)
 
    Polyhedral Hollow Ball packing is made from heat resistant and chemical corrosion resistant plastics, and the application

temperature in media ranges from 60 to 150 degrees.


    Plastic Polyhedral Hollow Ball (PP, PE, PVC, CPVC, RPP )

is also called plastic multi-aspect hollow ball, polyhedral hollow ball packing composed of two hemispheres which will form

into a ball. And each hemisphere consists of a number of half fan-shaped leaves, the upper and lower leaves in a staggered

arrangement. The design concept is advanced and the structure is reasonable. Plastic Polyhedral hollow balls have the virtue

of light weight, wide free space, small wind resistance, and good surface hydrophilic, big full wet surface area and

convenient filling in the equipment and sound usage effect.


    Plastic polyhedral Hollow Ball can be used in sewage treatment, desulfurization of CO2 in power plant, desulfuration and

purified water tower packing. Plastic multi-aspect hollow ball is a new type of high-efficiency tower packing applied in

water treatment equipment.


    Pall rings: made in various materials, used in massive applications


    Pall rings are the most frequently used form of random packaging. They are made of metal and plastic. They also have

different applications. Our experts will give you the most beneficial info about pall rings through this blog at Linquip. To

find more, read on.


    What are Pall Rings?


    As said above, pall Rings are a random ring-type packaging with a well-established success background and a globally

distributed base. They try to increase the use of packaging by disrupting the flow by providing an increased number of edges

while reducing the volume of the ring packing medium itself. Pall rings have  identical cylindrical dimensions but have

window rows that improve the surface area size. They are ideal for low-pressure drops and applications with high power. They

have randomness and relatively high liquid retention that promotes high absorption, especially if the reaction rate is slow.

Pall rings’ cross structure makes them mechanically robust and ideal for deeply packed beds.


    What are Pall Rings Used for?


    Pall ring is applied in a variety of areas, including:


   
       
            Different Separation and Absorption
       
   
   
       
            Absorption and Stripping Services
       
   
   
       
            Steam Stripping
       
   
   
       
            Quench Towers
       
   
   
       
            Direct Contact Cooling
       
   
   
       
            Reaction Towers
       
   
   
       
            Distillation Columns
       
   
   
       
            Tower Packing
       
   


    Plastic pall rings


    Random packaging has been used for over 50 years to boost the efficiency of a tower.


    In comparison with high-performance packing, plastic pall rings are less sensitive to liquid distribution quality and

have a higher hold-up and residence time. Although plastic pall rings do not have “high performance” characteristics, they

are well known for their performance.


    Plastic pall rings, as one type of pall rings, can be made of different shapes for different applications. In gas and

liquid separators applications, for example, they are increasingly popular. They have excellent chemical resistance, the

stability of the temperature, and mechanical strength. They are made of polypropylene pall ring, Polyethylene pall ring, RPP

pall ring, PVDF pall ring, PVC pall ring, and CPVC pall ring.


    The composition of plastic pall rings varies from the ceramic pall ring and metallic pall ring. Two levels of windows on

the cylinders wall and ligules bend inside the ring axes on the cylinders’ wall for the metal and ceramic ring. The plastic

cylinder wall is fitted with two layers of windows and the fingers or webs bow inward and form different forms. The handling

efficiency of the pall ring is 50 percent greater than the ring with the same decompression condition. The mass pressure is

meanwhile at the same treatment half below the Raschig ring. Moreover, the efficiency of transfer will increase by 20%.


    Metal Pall Rings


    Metal pall rings are a significant type of pall rings. Metal pall rings can be customized into different sizes. In very

hostle environments, they are more resistant to corrosion and rust compared with plastic pall rings. Metal pall rings are

made primarily from carbon steel, galvanized steel, and other materials. There are two layers of windows on the cylinder wall

close to the ceramic pall ring. And there are five ligules in each sheet, which bend inwards into the ring axis.


    Metal pall rings are used in quench towers, direct contact cooling applications, atmospheric pressure separation, and

absorption applications, places in which vacuum is critical to the low-pressure drop, and applications of steam stripping.


    Overview About Mist Eliminators


    Mist eliminators, also known as demisters, are devices that remove liquid droplets or vapor from the work atmosphere.

This device has found some applications in many industries where such vapors are released as a by-product of the different

chemical processes. Manufacturers produce standard or specialized devices to work as an important part of various industrial

operations which include absorption towers, distillation towers, separation tanks, gas separators, evaporators, and so on.

Various industries like metallurgy, petroleum, medicine manufacturing use demisters in their production processes or

environmental protection measures.



    Working Principle of a Mist Eliminator


    Standard demisting devices work on the principles of inertia and dispersion. The liquid vapor rises with the gas and

passes through the eliminator pads. These pads are fitted with wire meshes with openings that correspond to the predetermined

average vapor droplet size, which is generally in the range of 3 to 5 micrometers. Due to the increasing inertia of these

droplets, they get attached to the wire meshes. With subsequent passes, these collected droplets get heavier and heavier due

to the tensile and adhesive properties of liquids, ultimately falling off the pads. In this manner, the vapor liquid is

essentially separated from the gaseous emissions passing through standard eliminator pads.


    Advantages


    Eliminator manufacturers of today produce demisters of various sizes and capillary openings based on the above principle.

A standard mist eliminator has various advantages as listed below.


    · It is an essentially simple device; its size is only dependent on the gaseous emission pathway dimensions


    · For such a basic device, it is highly efficient in removing liquid vapors with minimum disturbance to the actual

process


    · Eliminators improve the output by removing vaporized impurities; they also make gaseous emissions, safer by helping to

separate potentially harmful compounds


    · With no external power needed for its operation, it is a cost-saving device


    · The liquid deposits may be collected and re-processed


    Types


    According to the requirements of specific industries, there are various types of these devices produced and operating in

several industrial applications. However, we may segregate mist eliminator devices into three basic categories as discussed

below.


    Standard Mist Eliminator


    These are the basic demisters that may be used in normal work environments. These devices can work efficiently in

standard gaseous emissions, separating liquefied vapors. The mesh sizes of these devices are bigger, and they can sustain low

to moderate amounts of gas pressure.


   



QR code
Report this ad Leave a review

Related ads