Springboard Biodiesel Go/No-Go Kit
How to use the Go/No-Go Kit
By employing an acid-catalyzed esterification before the standard base-catalyzed transesterification, the BioPro processors accomplish two important things:
- the need to titrate typical used oil is eliminated
- a much wider variety of oil can be used than in most processors
Nevertheless, some oils may be encountered which may have a free fatty acid level higher than the BioPro can process. Springboard Biodiesel has developed a quick test to determine the suitability of a particular oil sample.
Included in the Go/No-Go kit:
- (10) Go/No-Go vials
- (1) one milliliter syringe
For easy use:
- Simply take a 1 ml sample of the feedstock in question.
- Add this to one of the pre-measured Go/No-Go vials.
- Shake vigorously for 10 seconds.
- If the sample stays purple, it is a Go.
Make sure that the oil is free of water and particulates, and it will process well in your machine. (This test only measures FFA levels in the feedstock. Please refer to the section in your owners manual entitled Feedstock for further information or see our website page on feedstocks.)
If the sample turns yellow, it is a No-Go, the FFA (free fatty acid) level is so high that it is not recommended for processing in the BioPro.
Theory behind the test
Each vial is set to change color if the sample of feedstock is 5% FFA or greater.
If you want to tell more precisely how acidic the sample of feedstock is, simply see how much of it is needed to turn the fluid yellow.For example, if it takes 2 ml of oil to turn the fluid in the vial yellow, then the sample of oil is only 2.5% FFA.If it only takes ½ of a milliliter of oil to turn the fluid yellow, then there is 10% FFA in the oil.Please take note of the accompanying chart in your owners manual on page 25 to see the ramifications that this has for biodiesel processing. Many customers are able to use this information to dilute high FFA oil from one source with low FFA oil from another source. This allows them to process all of the potential feedstock they are able to find.
For those with experience at waste oil titrations
Percent FFA was used in this test instead of titration number due to the fact that it is an unambiguous measurement. (Titration methods can vary.) If a user were to use the titration method described at Utah Biodiesel Supply, you could convert this to a percent FFA by first subtracting 7 from the KOH result or 5.5 from the NaOH result. Then, you would divide by 1.3 if using NaOH or 1.8 if using KOH. This will give the approximate percent FFA in the feedstock.For example, a KOH titration of 16 would equate to 5% FFA.
To go from %FFA to titration number you would use the reverse formula:
(%FFA × 1.3) + 5.5 for NaOH
and
(%FFA × 1.8) + 7.0 for KOH
Please note that on some very rare occasions, the oil is contaminated with an acid of a mineral origin such as hydrochloric acid which is used as a cleaner.In such circumstances a sample could pass the Go/No-Go test but not be able to be processed.
Frequently asked questions
How do you use a Springboard Biodiesel Go/No-Go kit to test oil?
Draw a 1 ml sample of the feedstock with the included syringe, add it to one of the pre-measured Go/No-Go vials, and shake vigorously for 10 seconds. If the fluid stays purple, the oil is a Go; if it turns yellow, it is a No-Go and is not recommended for processing in a BioPro.
Each kit contains ten vials and one 1 ml syringe. Mix the oil well before sampling so the result reflects the whole container.
What free fatty acid level makes oil a No-Go for a BioPro processor?
Oil with 5% free fatty acids (FFA) or more is a No-Go. Each Go/No-Go vial is calibrated to change from purple to yellow when a 1 ml sample reaches 5% FFA, which is the maximum level recommended for BioPro processing.
Below that level, the BioPro’s acid-catalyzed esterification stage reduces the free fatty acids before the base-catalyzed transesterification, which is why typical used cooking oil does not need to be titrated first.
Can a Go/No-Go vial estimate the exact FFA percentage of used cooking oil?
Yes. Instead of adding a fixed 1 ml, add oil gradually and note how much it takes to turn the fluid yellow. If it takes 2 ml, the oil is about 2.5% FFA; if only 0.5 ml turns it yellow, the oil is about 10% FFA.
This works because each vial is set to change color at 5% FFA for a 1 ml sample, so the more oil it takes to change color, the lower the oil’s FFA level. The owner’s manual includes a chart explaining what different FFA levels mean for processing.
Can I blend high-FFA oil with low-FFA oil so a BioPro can process it?
Yes. Many BioPro owners dilute high-FFA oil from one source with low-FFA oil from another so the blend falls below the 5% FFA limit. This lets them process more of the feedstock they collect instead of rejecting a No-Go source outright.
Use Go/No-Go vials to estimate the FFA level of each oil, mix in proportions that bring the blend safely under 5%, then test the mixed oil before loading it. Make sure every source is also dry and free of particulates.
Can oil pass the Go/No-Go test and still fail to make biodiesel in a BioPro?
Yes. The Go/No-Go test measures only free fatty acid content. Oil that passes must also be free of water and particulates, since wet or dirty feedstock can still cause poor or failed reactions.
In rare cases, oil is contaminated with a mineral acid, such as hydrochloric acid used as a cleaner. Such a sample can pass the Go/No-Go test but still not process. If a batch fails despite a Go result, consider contamination at the oil source.
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