Frequently Asked questions :
What is the difference between "WET" and "DRY" washing?
Wet washing is still widely used and is a very effective means of removing excess contaminants and remaining production chemicals from biodiesel. A fine water mist is sprayed over the fuel and as the water settles to the base of the container the impurities are removed. A major disadvantage of wet washing is the time taken for the majority of the water to settle out. Usually a 24 hour period is required for this stage of the production process to be efficient and cost effective. Final water and particulate removal can be achieved by using a BD6000 filtration system. Water shortages and effluent water disposal costs also need to be taken into account when wet washing is used.
Dry washing is the process of using a Magnesium Silicate power to neutralise fluid contaminants. Magnesol is the international trade name for this product.
Absorbent purification (dry washing) of mono-alkyl esters with Magnesol, a synthetic magnesium silicate, compares favourably to the traditional water wash purification method followed by drying. Purification with Magnesol has proved very competitive to the traditional water wash process.
Dry washing has its best results when a closed reactor is used. A closed reactor relies on pressure and temperature (as high as 90°C) which ensures that the methanol is vented properly and glycerol separation is clearly defined.
The image above shows a closed reactor-Image supplied by UK FuelTech
What do you mean by 'agitation?"
Agitation is the initial mixing of the Magnesol with the biodiesel in a mixing tank. This is a simple process whereby the biodiesel is stirred and mixed to ensure the Magnesol powder is effectively "wetted out" before in enters the Wash Diffuser. Electrical or air-operated agitators can also be employed to further decrease the mixing time. This can also be done manually if required.
Typical agitation process shown above. Agitators are not supplied as standard with the Wash unit, but are readily available if required.
How effective is the Wash Diffuser?
Following agitation of the Magnesol powder in the 'mixing tank" , the biodiesel and the Magnesol powder mix and react lightly for the first time . The flow from the pump passes through the inlet head of the Wash Diffuser and down the central stem to enhance the mixing process. The fluid, now containing Magnesol particulate, will then try to escape from the outlet of the Wash Diffuser. However, Magnesol particulate is first captured in the 1 micron diffuser cell (now pressurised) , allowing for increased washing efficiency. By allowing for a slow ingress of Magnesol particulate, the diffuser cell will fill up slowly with Magnesol powder, forming a filtrate. This filtrate will increase the impurity absorption process. The Wash unit is designed to introduce the Magnesol powder slowly into the diffuser cell as failure to do this will result in a crust forming on the top layer of the Magnesol and thereby only using a small percentage of the powder in the reaction process.
A dry diffuser cell after use.
How much Magnesol powder do I use in one wash?
The Magnesol Wash Diffuser is designed to clean up to 1000-2000 litres in 2 hours. Obviously the length of the wash will depend on the starting quality of the unwashed biodiesel. If poor quality, unfiltered WVO is used this may cause the reaction time to increase. This would mean that ± 5kg of Magnesol powder is required for the wash process. The increased capacity of the diffuser cell allows for 5kg of Magnesol powder to partake in the wash reaction process, thereby greatly intensifying the pressurised wash reaction. The performance of the Wash Diffuser becomes clearly visible once full charge has been achieved.
What will happen if I put too much Magnesol into the wash?
The Magnesol holding capacity of a diffuser cell is 5kg , so there is excellent capacity to start with. By putting too much Magnesol into the wash tank , the diffuser cell will fill up far too quickly and may need to be emptied during the wash process. This would also result in the particulate holding capacity of the diffuser cell being exceeded.
As the cell is now full of Magnesol particulate, the fluid may attempt to take the path of least resistance and find an alternate path to the outlet port, possibly by-passing the filter media. This could potentially cause serious problems down-stream. In order to prevent any mishaps, a pressure gauge is fitted to the Wash reactor showing when the diffuser cell needs to be emptied in order to prevent this problem occurring. An additional safety switch will shut the unit off if the ideal operating pressure is exceeded.
Washing in smaller volumes is advisable. An 800 litre wash is ideal.
My pre-washed biodiesel looks very cloudy? Why is this?
A common cause of cloudy biodiesel would be water or moisture content. Biodiesel is naturally hygroscopic which means that it is constantly searching for moisture from the atmosphere. Water ingress is most common during the settling stage i.e. when glycerol is settling, usually an 8 hour period overnight.
Try to keep settling tanks as full as possible and to have adequate sealing to prevent unnecessary ingress of moisture. Should there be a high moisture content, any water, once it reacts with Magnesol may cause the biodiesel to become cloudy.
The water and any excess contaminants can be removed by effective multi-pass filtration.
Waxing in cold weather: In cold weather biodiesel is subject to wax build-up. Should wax be present during the wash process, the end-results may be poor. Wax can be effectively removed by multi-passing filtration of the fluid prior to the wash process using the Soap Trap.
Why do I need a "Soap Trap"?
If you were to follow your production guidelines to the letter after allowing adequate time for WVO to settle, then you may not need a Soap Trap. However, a Soap Trap. is included as standard with the Wash Diffuser package just in case it is required.
Soap Trap. shown above with 150 micron Stainless Steel re-cleanable element.
I have just completed a dry wash using Magnesol and my biodiesel does not appear any clearer?
With Magnesol washing it may be that you will not always "visually" see a vast improvement in the fluid cleanliness until the final filtration stage. Magnesol is responsible for acidic neutralisation of the biodiesel and the effects of the acidic level reductions may not be visible to the naked eye at first.
However, existing users of the Wash Diffuser have seen substantial improvements in the visual quality of the biodiesel in a very short time. Best visual improvements can be seen when the Wash reactor is fully charged.
The high performance filtration efficiency of the diffuser cell within the Wash Diffuser, will allow for maximum Magnesol capture. The diffuser cell is low cost and will need to be replaced over time. Failure to change the diffuser cell may allow for Magnesol particulate to escape from the filter media and migrate back into the wash. This will cause a slight cloudiness of the fluid. Change the diffuser cell, check all internal seals are in place and undamaged and continue the wash process.
My Wash unit is always cutting out?
Safety is a major concern during biodiesel production. A pressure shut off switch is fitted to the unit to switch it off when a safe operating pressure is exceeded.
One of the biggest problems in biodiesel manufacture is the quality of the Waste Vegetable oil. If WVO has not had adequate settling before the reaction, it may be likely that soaps are present in the fluid at the wash stage. The soaps need to be effectively removed before the wash is undertaken, as these will interfere with the whole process.
A 'soap trap" is supplied with the wash diffuser to capture excess soaps.
Start the unit and continue the wash process.
The sample above (left) shows high FFA content WVO that should be allowed adequate settling time before the reaction process. The sample on the right shows biodiesel after the Magnesol wash unit and final polishing using the BD6000.
Do you have a larger capacity washing unit?
Yes, we do. Larger wash capacity is achieved by increasing the Magnesol holding capacity of the diffuser cell. Multiple diffuser cell units are available on request.
Can I use the biodiesel directly after it has been "dry" washed?
Due to the very fine nature of the Magnesol particulate, final filtration is ESSENTIAL . It is advisable that "wash" areas and "final polishing" areas remain apart so as not to cross-contaminate the final product. Magnesol particulate, when wet, may form aggressive crystals resembling fine "sea sand", which most certainly will cause problems in engine systems.
The BD6000 final filtration units are fitted with a 1 micron pre-filters, and the final polishing filters will ensure that all particulate is captured and any remaining moisture is removed effectively. Best results are achieved by multi-pass filtration.
The sample above shows wet Magnesol powder. This needs to be removed effectively and will cause problems to engine systems if final filtration is not applied.
I still have Magnesol particulate present in my washed biodiesel?
It may be the case that Magnesol particulate has somehow made its way into the finished product. Check the seals of the wash reactor. The seals are Viton construction and are very compatible with biodiesel. However, these may need replacing over time. Try to keep your wash section and final filtration section as separate as possible to prevent any cross-contamination. Any remaining Magnesol particulate can be removed by repeating the wash, allowing adequate settling time or by effective multi-pass filtration.
How do I know when the Magnesol wash is complete?
It is best to run the wash process on a set time scale. Two hours for 1000-2000 litres is advised, but longer washes may be required depending on initial contamination levels. The overall efficiency of the wash will depend on initial quality of the biodiesel, concentration, dose level and contact time. The 2 hour period is based on a fully charged reactor. Reactor charging time is ±20 minutes after the agitation process in the mix-tank.
Why is my pump making a spluttering, droning noise?
The wash unit pump needs to be primed when first put into use. This can be done by opening the priming plug and pouring biodiesel into the pump. This will only need to be done on the first occasion.
There is no flow from the outlet hose, what am I doing wrong?
There could be several reasons for this , the most common are:
- Check the diffuser cell to see if it needs replacing. These will need to be replaced over time as the filter media will eventually "blind".
- Make sure your wash system pump is fully primed.
What will happen to my vehicle if I run it on un-filtered biodiesel?
Contaminated biodiesel may cause the following problems to engines:
- Corrosion of fuel injection components
- Elastomeric Seal Failures
- Low pressure fuel injection blockage
- Fuel injector spray hole blockage
- Increased dilution and polymerisation of engine sump oil
- Pump seizures due to high fuel viscosity at low temperatures
- Increased injection pressure
- Water is the central promoter of rust
I am considering re-selling my biodiesel. Do I need to filter it before I sell it on?
Yes, it would be advisable to do so to prevent any potential claims against you. In addition to the above list of problems that contaminated biodiesel may cause, a few more problems could occur namely:
- Free methanol in biodiesel corrodes aluminium & zinc and results in a low flash point. High possibility of failure due to corrosion of fuel injection equipment.
- Biodiesel process chemicals such as potassium and sodium compounds and solid particulate will result in blocked nozzles.
- Dissolved water in biodiesel will lead to the reversion of biodiesel to fatty acid and will result in filter blockage.
- Free water in mixtures causes corrosion, sustains bacteria, increases the electrical conductivity of fuel which results in sludging and corrosion of fuel injection equipment.
- Free glycerine, mono-& di-glyceride may lead to corrosion of non-ferrous metals, will leave sediments on moving parts causing lacquering resulting in filter clogging.
- High viscosity at low temperatures may result in excessive heat locally in rotary distributor pumps and higher stressed components. This could lead to pump seizures and poor nozzle spray. Corrosive acids (formic and acetic) will corrode all metal parts if not removed effectively and will result in failure of fuel injection equipment.
Do I really need to filter my biodiesel?
All responsible reactor manufacturers will advise of the need for filtration to remove excess water and contaminants from the final product. Final Filtration is essential when a Magnesol wash is used.
I heard that I should not be concerned about "particulate contamination', as long as my fuel is relatively clean everything should be okay?
This is not true at all. Solid particulate will cause system damage. Particulate sizes could be smaller than 4 micron and will not be visible to the naked eye. So even if the fluid looks clean it may still contain microscopic harmful contaminants that can only be removed with effective filtration.
What do you mean by Multi-pass Filtration?
The SDFC replacement cartridges rely on absorption to remove solid contaminants and water from biodiesel. By circulating your biodiesel several times, the elements will have time to "absorb" the water and remove harmful contaminants down to 1 micron. The pump on the BD6000 is continuously rated and is ideal to be left running for extended periods. It is best to have an IBC storage container dedicate to the filtration process. This should be the penultimate phase of the stages filtration process before dispensing the fuel into a final dispensing IBC for resale.
How long will the SDFC elements last?
Each filter cartridge will hold 800ml of water and ± 2kg of solid contaminant. If dry washing using magnesol, the elements will last for several polished. With a single SDFC element capable of holding 2kg of contaminant and with the minimal down-stream migration of magnesol particulate from the Wash Diffuser , excellent element life will be experienced.
The BD6000 (2 pot unit) will absorb 1.6 l of water per element change-out. A 4 pot version is available for larger production quantities and will remove twice this amount per element change-out.
We offer very attractive price breaks for larger quantity purchases of SDFC elements.
How long should I run the BD6000 polishing unit for?
The BD6000 is designed for multi-pass filtration and is continually rated for use over extended periods. Although you will see an immediate improvement in the cleanliness and clarity of the fuel in a single pass, the elements need time to absorb the water and contamination effectively.
How will I know when the filter elements need replacing?
This would depend on the composition of the contaminants in the biodiesel. In the case of solid contamination, the BD6000 is fitted with a pressure controlled cut-off switch that will switch the unit off when the pressure exceeds 4 bar. In the case of water contamination, as the filters absorb water from the biodiesel they will eventually "soften up" as the water is retained. This means that the cut off blockage pressure of 4 bar is not possible to reach. It is therefore best to replace the elements on a "time used" basis. This will vary from user to user depending on the quality of their production process as well as on the settling procedures used and settling time allowed.
A pre-filter is fitted as standard to the BD6000 filtration system, allowing a wide range micron size elements to be used. Pre-filters are low cost and will significantly increase the life expectancy of the SDFC final polishing filters.
How many litres per day can I filter through the BD6000?
Smaller production quantities up to 1000 litres per day can be effectively handled by the BD6000 2 pot unit. (flow rate 600l/hr) For larger production quantities it is better to opt for the larger BD6000 4 pot unit with increased flow rate of 1300l /hr .
How long will I need to run the BD6000 unit for before my fuel is clean?
Multi-pass filtration is required to achieve the best results. Try to circulate your storage container at 3-4 times to allow for maximum filtration efficiency.
Why is a pre-filter fitted to the BD6000 unit?
A spun-bonded media pre-filter is fitted for numerous reasons:
- To extend the life of the SDFC replacement elements
- To capture any large contaminants
- To capture any wax build-up common in colder months
- To capture any migrant Magnesol particulate from the wash process
- As an early tell-tale sign should you still have Free fatty acids in the final product, you will need to address earlier productions methods accordingly
How can I guarantee the best quality biodiesel?
The quality of the final product is largely dependent on the quality of the Waste Vegetable oil used. Source quality WVO wherever possible and ensure that you filter the WVO to the desired cleanliness before commencing production.
Follow your reaction manufacturers guide-lines to the letter. Overstretching the capacity of the reactor is not advisable. Allow for adequate storage and settling processes.
Wash using either the Wet or Dry method, with dry washing best suited to the closed reactor.
Use a dedicated filtration IBC and filter your final fuel to 3 micron or better
I have invested lots of money in my biodiesel reactor. I would really like your filtration system but cannot afford it now?
We agree the initial investment costs may be high, depending on your production quantities, and reactor of choice. It is however advisable to build in "good practice" from the very beginning.
Where does the BD6000 fit into the final production process?
The DB6000 is used downstream of the reaction and wash processes. It is most effective in removing water and solid contaminants from the final product.
My fuel has been settling for a week and I can see no improvement whatsoever?
Take a small sample and examine it closely. It is quite common for inexperienced producers to miscalculate the titration levels. This may result in Free Fatty Acids still being present in the final product after the reaction process. The presence of the FFAs will hinder the settling process, cause problems with wet and dry washing techniques, and cause serious engine damage.
This is one of the most common problems in the production of biodiesel. Un-filtered waste vegetable oil contains a high percentage of free fatty acids. Heating and stage filtrations are essential at this point. By "stage filtration' we mean the removal of contaminants starting at 400 micron and stepping up the filtration efficiency to a desired level of cleanliness. Several micron sizes are available with 400, 200, 100 micron in re-cleanable nylon construction. 100. 75, 20, 10, 5, 3 and 1 micron are available in disposable format.
Do I really need to filter my incoming Waste Vegetable Oil (WVO)?
In the biodiesel production process, it is essential that Waste Vegetable Oil (WVO) is filtered prior to the reaction.
By allowing for adequate settling and heating procedures, the quality of the WVO is greatly improved. Heating will allow any excess moisture to be removed and good filtration is required to capture any excess Free Fatty Acids and harmful contaminants.
FREE FATTY ACIDS (FFAs) are the thick, white creamy deposit that will settle on the bed of the IBC storage container.
In the UK , several large waste oil contractors have discontinued filtering the WVO that is now being delivered to biodiesel production facilities.
Even if production chemical mixes are applied in the correct ratio's, there is still a possibility that FFA's may be present in the finished product. These contaminants will cause system damage to vehicles and will lengthen the wash process.
Our WVO filtration package is an efficient, cost-effective way of cleaning up WVO to ensure excellent quality biodiesel.
Our package includes a rugged frame and sturdy dirt tolerant screw pump ideal for WVO transfer. We then offer STAGED FILTRATION comprising of two (or more) filter housings with 400 micron and 200 micron nylon re-cleanable elements to keep your costs down.
The filter housings are available in a low-cost polyprop construction or in Stainless Steel, with varying sizes to suit all production capacities.
Is Rape Seed Oil (RSO) better than WVO?
With the declining quality of WVO, several producers are moving over to RSO, or a mix of RSO and WVO.
With RSO it is easier to control the overall quality of your process. However good filtration is still required to ensure that RSO is at the desired cleanliness level to commence production.
Freshly pressed RSO is highly contaminated with seed and 'cake". These aggressive contaminants will need to be removed effectively.
Our RSO filtration package is a cost-effective way of cleaning up rape seed oil to ensure excellent quality biodiesel.
Our package includes a sturdy dirt tolerant screw pump ideal for RSO transfer. We then offer STAGE FILTRATION comprising of two (or more) filter housings with 400 micron and 200 micron nylon re-cleanable elements to keep your costs down.
The filter housings are available in a low-cost poly-prop construction or in Stainless Steel, with varying sizes to suit all production capacities.
