How do Ion Exchange Resins work?
Ion Exchange Resins are used in columns to polish contaminants derived in biodiesel production to meet European / USA standards. It is primarily used to remove glycerine, soaps, caution salts (some derived from the esterification process catalyst), and water.
Ion Exchange Resins have a very limited capacity for methanol and hence it is best to ensure effective de-methylation prior to the columns if used in final polishing to meet methanol limits / flash point defined in the international standards.
With Ion Exchange resins, the better the quality of the bio-diesel feed to the plant, the better the resin will perform. As oil supplies become less easy to obtain some companies are turning to poorer quality oils, some contaminated with animal fats etc. and this will shorten the resin life as the resin can become fouled.
In the majority of cases, resins are used in final polishing and treating good quality bio-diesel at specific flow rates of 2-3 BV/h to achieve B100 specifications.
Ion exchange resins replace an ion in one form with another ion to "neutralize" the species. For example, soap molecules can be thought of as potassium or sodium oleate molecules.
In the case of Ion exchange resins, the potassium or sodium part of the soap would simply be replaced by the acidic ion exchange resin, probably hydrogen, to produce an acid (in this case a free fatty acid). This can be measured by acid value or FFA titration. Once the acid from the resin is spent, no more soap can be neutralised. This is why the resin can become spent more quickly when the initial soap content is more than 400-500 ppm.
A word of caution!
Some resin manufacturers claim that a single kilogram of resin can purify 900-1600 liters of biodiesel. Resin exhaustion, however, can start as low as 100 litres per kg, vastly different from the manufacturers claims of 1600 litres per kg.
As Waste cooking oil (WVO) is the predominant feed stock for producers using batch style processors, the results and cost implications may prove disadvantageous to biodiesel producers. When WVO is used as a base feed stock, high soap levels are present which may overwhelm resin capability. High methanol levels will hinder the resin efficiency and increase the resin exhaustion rate even more.
Even more sophisticated biodiesel processors with methanol recovery/removal systems, using virgin oils, are experiencing difficulty in achieving resin life. Typically these systems would achieve ±780 litres per kg of resin, still significantly below manufactures stated claims. The result is a significant increase in the cost per litre for purification.
How do you know if the resins are exhausted?
By using a PC9000 particle counter, the contamination counts will rise as the resin exhausts and will allow producers to monitor resin life in real-time and schedule resin change-outs accordingly.
Do I require any filtration with these resin systems?
Levels of contamination are not uncommon in the final product with resin systems. This can be verified by using a PATCH TEST KIT. These would include solid contaminants and possible moisture content. If the producer has not effectively cleaned out the column and not calculated the replenishing time of the resin accurately due to poor monitoring, this will further increase overall contamination levels and compound the problem. As production residues build up within the columns, so do contamination levels that could cause significant engine damage if not effectively removed. Final polishing is essential at this point.
Which resins are the best on the market?
There are a number of resins on the market today, some of which differ greatly in terms of performance and price. Some manufacturers claim to have fully dried products will perform better. However, one should beware of wet resins ,which are supplied by some other manufacturers. These wet resins are usually much cheaper, and can be more difficult to commission and may offer poorer performance. Some of these are sold in the sodium form, which means they will not remove excess catalyst from the final product and hence will not improve the TDS (total dissolved solids) in the final product. Many of those using wet sodium form resins have been disappointed. This is why the industry has a mixed view on resins in this application.
Please contact us to discuss our findings and recommendations.
Filtertechnik Resin Treatment Towers (Stainless Steel)
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Available with 10, 50, 100 and 200 kg resin holding capacity, Filtertechnik Resin Treatment Towers can configured to suit all production volumes. Our systems are scalable to allow for increased volume production, allowing for continuous production and reduced purification times.
As the unwashed biodiesel enters the treatment tower, the biodiesel passes through the resin removing production residues, fuel contaminants and soaps*. Flow rates, vessel design and resin bedding need to be governed accordingly in order to ensure maximum removal of production residues and soap.
All our products are CE rated and have been pressure tested to suit this application.
Each Treatment Tower is capable of purifying in the volumes as shown in the table below. Purification times can be shortened and production levels increased by adding extra towers to your purification line.
*resin life permitting
Filtertechnik Resin Purification systems
Filtertechnik's unique design configurations allow for a continuous flow during the wash process, thereby eliminating any downtime. Any number of Filtertechnik Resin Treatment Towers can be built into system designs, complete with pump, control panel and safety features. Flow rates can be governed accordingly to suit the number of towers in operation.
As the unwashed biodiesel enters the Filtertechnik Resin treatment tower, the fuel is purified in a single pass*. In the same passage of flow the washed fuel passes through a long-life final polishing bank to allow for the removal of residual production residues, moisture and soaps.
Filtertechnik systems are unique in that we offer high performance polishing and on-line traceability as standard.
*resin life permitting
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Example Model: FTRT2-4 |
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Please contact us for more information on these systems |
Advantages of Filtertechnik Resin Systems
Easily retrofitted to your existing production process
Low capital investment costs
Can be configured for continuous flow applications
Can replace or compliment your existing purification system
Single pass process- *resin life permitting
Saves Energy- no drying required
Save capital..no expensive centrifuges, dryers
Completely dry, waterless process
Traceability with PC9000 particle counter fitted
To view a system in operation please register for an open day
Biodiesel product catalogue
