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Liquid Filtration
Liquid Filtration by Ernest Mayer, E. Mayer Filtration Consulting, LLC
Ernest Mayer, founder of E. Mayer Filtration Consulting, LLC, is a former senior consultant with DuPont, Wilmington, Del. He has specialized in solid/liquid separation since 1980, with a particular emphasis on environmental applications and filter media characterization. He also has taught many internal courses on solid/liquid separation and written more than 200 papers. He is chairman of the Users Committee of the American Filtration and Separations Society and winner of the society’s 2005 Lifetime Achievement Award.
How do I decrease percentage of solids entering the heat exchanger?
I have been assigned to manufacture an evaporator for liquid phase of digestate originating from biogas plant. My inputs are that liquid digestate contains around 7.7% of dispersed solids and the biggest particle is maximum 500 micron in diameter (size of perforation on a screw press sieve that performs primary solid-liquid separation). My goal is to try and decrease percentage of solids entering the heat exchanger as much as possible or economically viable so to diminish heat transfer surface fouling problems. Which filtration options do you find most adequate for aforementioned task?
Before mechanical screw press separation I have from 12% to 18% of solids and after mechanical screw press separator I get from minimum 4 to maximum 7.7% of solids in liquid phase. Solid phase after separation has 27%-33% of solids and I would like to evaporate enough water from the liquid phase so to achieve similar percentage of solids (27%-33%) in the liquid phase as well. I want to do it through evaporation. Since my goal is to obtain an end product (solid and liquid phase mixed after evaporation) with around 30% of solids, and I can not do that directly through evaporator (due to fouling of inner heat exchange surfaces of evaporator), I decided to raise percentage of solids entering the evaporator only to around 14% which proved to be maximum practical limit. Because I want to evaporate as much water as possible and I'm limited with 14% solids (we have enough thermal energy though) it is very important to maximally lower percentage of solids prior entering the evaporator. This way when I reach maximum of 14% of solids in the evaporator I will have great portion of water already evaporated and only small amount will remain. The lower percentage of solids entering the evaporator the smaller portion of water remains when 14% of solids is reached after evaporation. This is OK for me since this evaporation product being concentrated to 14% of solids will be mixed with the mechanically separated solid phase (27%-33% solids) afterward. Weight ratio between solid phase (30% solids) and liquid phase (14% solids) will be tipped heavily towards solid phase so adding this 14% liquid phase should get me only slight decrease of percentage of solids in solid phase (from 30 to around 29%). Therefore I need as effective filtering of solids as possible prior to entering the evaporator.
Just to point out that we did try to raise percentage of solids in the evaporator but it could have only been done in scraped surface evaporators which are costly to produce and costly to operate so I can not use them.
What can I do to lower these maximum 7.7% of solids to lets say 0.1% (if I do that, then my math of lowering 30% of solids in the end product to 29% is OK)?
Category: Liquid Filtration
Is there a way to scale down batch filtration through bag and cartridge filters?
Is there a way to scale down batch filtration through bag and cartridge filters? We experience variable filtration time of suspensions of different batches of active charcoal and would like to evaluate the performance of the filter media on a lab scale (0.5 - 5 L). In the plant we pressure filter active charcoal suspensions from a batch reactor (stirred tank) through a three-stage filter system: a 5 um bag filter, a 1 um cartridge filter, and a 0.2 um (absolute) cartridge filter. The setup uses 10 in cartridges.
Category: Liquid Filtration
What is the best filter for Calcium Nitrate?
We are using a liquid 75% Calcium Nitrate solution.After filling stainless steel tanks, there is a cloudiness. When we allow to settle, there is a small amount of white residue visible at the bottom of the tank. What would be the best filter to work with the Calcium Nitrate.
Category: Liquid Filtration
How do we increase suspension material removal?
We have a wastewater process involving 3 micron bag filtration then tied to activated carbon drums in a series to remove suspension materials and active pollutants from agricultural pesticide tank washing. We are looking to increase suspension material removal and remove more active emulsifying concentrate pollutants from the filtration stream. Any ideas?
Category: Liquid Filtration
What is the proper filter to remove suspended coal tar?
Can you suggest a filter to remove suspended coal tar particles from the ammonia liquor in the pressure line?
Category: Liquid Filtration
What type of filter should be used?
We are experiencing plugging of suction strainer (Y type, Mesh 40) of Lean MEG pump every three hours. These plugging materials are some type of polymerized MEG and these are polymerized in the MEG regeneration, upstream of the pump at 0.06 barg and 126 deg C. We are going to install a filter upstream of this pump as per following requirement:
- MEG flowrate 18m3/h
- Double filter to be considered
- Clean-up cycle to be every 2 weeks.
- To remove particle size bigger than 25μm
Category: Liquid Filtration
Can you suggest a filter that can be used repeatedly?
We have to filter used wax having 25 micron and bigger particles. After making molten state, which type of filter can be effectively used? The wax is heated and made molten state (90 degrees C) in a 500 liter capacity heated vessel. The filter elements specially designed get choked after each batch and cannot be reused resulting in very high cost. This replacement of filter element makes the reuse of wax uneconomical. Can you suggest a filter that can be used repeatedly?
Category: Liquid Filtration
What is the best filter for processing a slurry?
I am processing a slurry of reacted Lactic Acid, Ca and Mg. Once solubilized and at a temperature of 190 degrees F, we want to run it through a filter to get rid of any "non solubilized" material and then to a holding tank to be spray dried. The solids content is 40% and we have been using a bag/sock filter at 5 micron and then again at 50 micron. Problem is the slurry goes solid on the surface of the filter and backs up the system, then it cools down and all the liquid goes solid. Any suggestions?
Category: Liquid Filtration
What is the best way to wash aluminum hydroxide precipitate?
What is the best way to wash aluminum hydroxide precipitate to a final conductivity of between 300-350 microsiemens/cm? Which will be best for my process: filter press, rotary vacuum filter or a separator?
Category: Liquid Filtration
For oil refinery applications, which type of filter should I choose?
I would like to install feed filters in a Kerosene hydrotreater unit upstream of reactor. The feed to the filter is straight-run light kerosene from crude units. These are the typical operating conditions:
- Feed flow: 290 m3/hr
- Feed Temp: 135-150 degrees C
- Pressure at filter: 4-5 kg/cm2g
- Viscosity: 0.357cP at 145 degrees C
- Typical dirt loading: 5-6 mg/liter (magnetic in nature)
- Filtering size: 25 micron
Category: Liquid Filtration
Can you suggest reference materials for safety issues in liquid-solids filtration?
Do you know of any articles or reports that deal with safety issues in liquid-solids filtration?
Category: Liquid Filtration
Can you suggest a pump that can handle abrasives?
I need to pump used lube oil at a temperature of 120 deg c. There are highly abrasive impurities consisting of activated carbon and perlite of 1%. 8 bar pressure is required to pump the oil through a filter press at 1500m lph. Can you suggest a pump that can do this duty while still being able to handle the abrasives?
Category: Liquid Filtration
Can you suggest a better filtration method for lubricants?
We are blending automotive and industrial lubricants in which we use virgin and recycled base oil. In recycle base oil there are suspended dust particles that we can't see with the naked eyes initially. In lines we are using PP filter bags for filtration of 10 - 25 microns before pump and the pump capacity is of 15 hp gear pump of 1440 RPM.(depends upon viscosity).(viscosity of oil ranges from 5 to 40 CST at 100 degrees centigrade, but the blending process is at room temp -- 30 degrees centigrade.)
But after filtration and after a few days we can see with our eyes,brown or black dust particles settled in the bottom of the cans, or if we take the same oil in a 500 ml glass cyliders, we can observe the same after few days, and also after settling particles, oil becomes more clear and bright.
I would like to ask you whether this problem can be solved by using 1 to 5 microns filter bags, as oil is difficult to pass through these bags or we use 20 to 25 hp motors so that oil can pass through it easily.
Category: Liquid Filtration
What's the best way to filter fine particle from oil?
I am looking to filter the fine particles from oil (smaller than 10um.) The oil viscosity is quite high, approximately 400cP, the filtration is a batch-wise process where we need to filter about 100kg per batch. The solid concentration in the liquid is very, very low -- <5 .
Category: Liquid Filtration
Is there a quick method to remove particles and get a clear solution?
We want to filter the calcium from calcium alkyl benzene sulfonate. Currently we use a plate filter by using filter aid but the results are not satisfactory and take too much time. Is there a quick method to remove/filter the calcium particles and get the clear solution? What type of filter cloth should use?
Category: Liquid Filtration
Is there equipment that filters, washes and dries?
Is there any equipment that is used as reaction (precipitation) plus filtration plus solvent wash plus filtration cum dryer in series? Such equipment can reduce capital cost significantly and also result in almost no solids handling, since in our case dried product has to be dissolved in a solvent.
Category: Liquid Filtration
What is the best filter for handling toxic substances?
In case of closed filtration of solvent with solutes >50 micron, what is the best filter available for batch operation, with respect to fewer solid handling problems, ease of operation and comparatively economical in the pesticide industry with hazardous product? Is the Nustche filter a reasonable choice?
Category: Liquid Filtration
Is there a low-cost filtration method that can remove the majority of solids?
We are treating anaerobically digester slurry from farming operations. A solids separator followed by gravity-fed screens leaves us with an 85 degree F liquid that still has a suspended solids content of 15000 mg/L (1.5%). The particle size is < 50 microns with a steep drop off below 20 micron. So still a high volume of relatively small particles need to be economically removed.
Category: Liquid Filtration
What's The Best Way To Filter Activated Clay?
I have a slurry of used lubricating oil containing activated clay. The intention is to regenerate the used oil. However, the slurry could not pass the stainless filter. I thought about using a cloth filter. What do you suggest?
Category: Liquid Filtration
Extracting Maximum Oil From The Slurry
We have a slurry of 50% solid concentration with solvent, hexane and oil. For closed/gas tight filtration, what you will suggest for 10 to 80 micron particles to get separated and extract maximum oil?
Category: Liquid Filtration
Finding An Appropriate Filter
What is your recommendation for an appropriate filter for the filtration of 90% concentration by weight Ammonium Nitrate solutions as per the following specs:
(1.) Temperature = 90 to 110 degrees C
(2.) Ph = 4.8- to 5.2 sp Gravity is 1.3 - 1.4
(3.) Liquor contains water, Ammonium Nitrate, mud/insoluble inorganics of size varying from 0.5 microns to a few hundred microns, organic coating agents that float as scum.
(4.) We are interested in a continuous filter, minimum turbidity
(5.) Other objective is to use Minimum quantity of water for cake washing.
(6.) Caution: Process medium is corrosive.
Presently our storage tanks/pumps are made of SS316. Filtration capacity requirement is around 8 - 10 m3/hr
Category: Liquid Filtration
Vacuum Belt Filters vs. Ceramic Disc Filters
What are the main differences between vacuum belt filters and ceramic disc filters in terms of capital and operational costs?
Category: Liquid Filtration
Finding a Filtration Scheme that Filters Properly and Efficiently
We are operating an old plate-and-frame filter press to filter polymer from the water/ascetic acid supernatent produced in the process. Local "artist" operators and SOPs based upon legend tend to provide inconsistent and non-scientific-based proposals for lifter press optimization. Could you direct me to a basic plate-and-frame filtration operation scheme designed to use the filter properly and most efficiently? Questions are very basic and include:
1. Feed from the top? Feed from the bottom?
2. Wash from the top? Wash from the bottom?
3. Blow down from top? Up from Bottom?
4. Cycle wash directions? Co-current or counter current washes?
5. Dilute feed at first? For how long?
6. Benefits of altering solids content in feed while loading? Variable feed rates?
Category: Liquid Filtration
Filtering Impurities From Polymer Solutions
We need to remove impurities such as solid particles from polymer solutions. The volume of the polymer solution for each batch is about 2000-3000 ml and the viscosity of the solution is around 1000-2000cP. The particle size we want to filter is 1-2um above. What kind of filter system is good for us?
Category: Liquid Filtration
Recommending appropriate filter for an aqueou slurry
Request for your recommendation for appropriate filter for the
filtration of aqueou slurry as per the following specs:
1. temp. = 30 to 60 deg C
2. Ph = 1.4 to 1.6
3. Slurry contains water, lactic acid, Calcium sulfate powder, traces of sulfuric acid.
4. Slurry concentration : 16 to 25 wt % Calcium sulfate
5. Pressure = 1 to 4 bar g.
6. We are interested in a continuous filter , minimum loss of lactic acid with the wet cake of Calcium sulfate (cake is to be rejected )
7. Other objective is to use Minimum quanity of water for cake washing.
8. Caution : Process medium is corrosive.
Category: Liquid Filtration
Appropriate Bag Filter
I am processing a liquid solution of H2SO4 with some metal particles. I want to filter this solution and filter out everything over 1 Micron in size. Any suggestions? Is there a bag filter that would be appropriate? This process will be run 3-4 times daily and I don't want to change cartridge filters every day.
Category: Liquid Filtration
Filters for gear oils
What types of filters should be used to filter out impurities in 100 gear oils. Particle count is important.
Category: Liquid Filtration
Use of activated carbon filter for removal of oil from urea mother liquor
We are pumping back 65 cubic meters per hour of urea mother liquor (approximately 70% concentration) to the crystallizer vessel after centrifuging urea crystals. Centrifuge oil seal leakage is a frequent problem contaminating return mother liquor with 90 PPM oil in it. Can we apply activated carbon filter to remove oil from urea solution?
How can we estimate filter sizing indicating: pressure drop across bed; activated carbon; equipment; steam regeneration required; final purity with respect to oil content; annual cost (maintenance and operation) of such filter; first investment cost; basic literature to size such device (rule of thumb).
Category: Liquid Filtration
Extract light fraction in oil
I'm using a proprietary thermal oil to heat different equipment. We are using around 250,000 L. The close-cup of a new oil is 210ºC and we are around 95ºC. Is there a way to extract the light fraction in this oil to come back to a more decent flash point? Either by filter or a kind of online distiller?
Category: Liquid Filtration
Filters for a waxy stream
What type of filtration would one use to remove fines from a waxy stream?
Category: Liquid Filtration
Filter requirements
We are running experiments about the extraction of hydrocolloids from fruits and we’re using filtration textiles with pore diameter of 0.021 mm in the lab. As we are planning to go on bench scale, the provider of the filter is telling us he can give us a filter with stainless steel mesh of 0.037 mm. He has a lot of experience in the industry and tells me we should have no worries and that this size should work fine. Should I believe this provider and purchase the machine?
Category: Liquid Filtration
Rules of thumb on UF systems
My process uses ultra filtration. There are many variables to watch on the system such as feed pressure, membrane pressure, recycle pressure, permeate flow rate and concentrate (reject) rate. What parameters are most important to watch? Is there a good resource for general rules of thumb on UF systems?
Category: Liquid Filtration
Filtration equipment for solids
During the depolymerization reaction of natural polysaccharides, the viscosity of the product reduces as per the requirement. The insolubles, like fiber, etc. are to be filtered off. We are facing a problem with the filtration using equipment such as a basket centrifuge. The filter cloth chokes immediately. What type of filtration equipment should be used?
Category: Liquid Filtration
Clogged filter press cloths
In our plastics reclaiming plant, we use high density salt water solutions to separate plastic by specific gravity. These solutions have higher viscosities than water. Some "dirt" always comes in with the plastic feedstock and ends up contaminating the fluids. We are concentrating the dirt in a clarifier (with polymer flocculant) and then filtering the clarifier bottoms to recover the fluid. The problem occurs when the recessed plate type filter press cloths tend to "slime" causing high delta P, low flow rates and wet cakes. We have tried adding diatomaceous earth, lime and perlite as "body feed" to improve permeability with limited success. Do you have any suggestions?
Category: Liquid Filtration
Filtering technology
I am a synthetic organic chemist by trade and find myself in a new position of carrying new products for an animal repellent company that incorporates predator animal urines in their products through the EPA registration process. The bacterial and viral protocols we have had developed through Cornell University School of Veterinary Medicine involve our company pasteurizing and filtering the animal urines. We hope to use through 5 and 0.2 um media to remove many bacteria and spores. I currently have limited equipment, other than gravity filtration materials, to attempt to carry this out. I have had difficulty even on the 25 um level with fluted papers. We will be facing the filtration of 5 to 55 gal lots in production and I need to filter a 1 gal lot for EPA testing ASAP. What route would you suggest I go and/or is there a filtering consultant who we could contract to perform the smaller filtration in the meantime? Any direction you can provide would be very much appreciated.
Category: Liquid Filtration
Selecting filtration equipment
What is the procedure for selecting filtration equipment? (i.e. Nutsche filter, filter press and centrifuge.) If possible, please explain with equations and calculations.
Category: Liquid Filtration
Hot oil filters
I want to filtrate hot oil (250°C) from solid matter. What is the best type of filter to use?
Category: Liquid Filtration
