Quality determination on diesels from waste engine oil and waste plastics
We would like to thank the following people for this project:
Pyrolyze, Peter and Raymundo, thank you for letting us do this project with you. The collaboration was very pleasant and it is very nice to contribute to your commitment to a cleaner planet
Martijn, thank you for guiding the project. In particular, preparing for our graduation assignment and helping us get ready for the next step in the school curriculum.
We would also like to thank both companies, Bureau Veritas and VPS, for opening up their labs and contributing to the project.
The aim of this project was to perform quantitative and physical analyzes on different Pyrolyze diesels. This diesel is produced from waste products of motor oil and plastics. These waste forms are treated with a Pyrolysis process developed by Pyrolyze. The Pyrolyze samples are:
- Unfiltered Pyrolyze gasoil from engine oil
- Unfiltered Pyrolyze gasoil from waste plastics (PS/PP/PE 1:1:1)
- Filtered Pyrolyze gasoil from waste plastic (PS/PP/PE 1:1:1)
In addition, the following diesels were used as reference:
- Tinq gasoil
- Shell gasoil
- Shell v-power gasoil
The analysis protocols used came from NEN-EN 590. The NEN-EN590 is a method that describes the quantitative and physical properties that all diesel fuels for the automotive sector must comply with within the European Union. The samples were measured at two laboratories, Bureau Veritas and VPS.
The results shows that the Pyrolyze samples do not comply with EN590. The densities of the analyzed samples are too low and the sulfur content is too high. The flash point of the gasoil from motor oil was very low, making it unanalyzable. The other parameters, water content, viscosity, ash content, manganese content, FAME and flash point of the gasoil plastic, are within specifications of NEN-EN590.
The results of both laboratories are in agreement.
Table 1 shows the abbreviations that appear in the study report.
Table 1 Abbreviations with meaning list
Table of contents
1.1.1 Main question.
1.1.2 Sub questions.
2.0 Material and Method.
2.1 Samples and Chemicals.
4.0 Discussion and Conclusion.
During this project, research was conducted into the quality of various diesels produced by Pyrolyze. Pyrolyze wants to offer a solution to one of the biggest problems of the 21st century, waste. With innovative pyrolysis technology, waste is converted into usable raw materials. Waste plastic, used motor oil and old car tires are converted into 3 fractions using pyrolysis:
- Gas fraction
- Naphtha fraction
- Diesel fraction
The gas fraction is used as fuel for the pyrolysis process. The diesel fraction from the pyrolysis system is filtered. The filtered diesel and naphtha fraction can be sold commercially as raw material and/or fuel. A residue remains in the reactor, which is referred to as carbon black.
Pyrolyze is interested in the quality of their 2 commercially useful products, the diesel fraction and the naphtha fraction. The comparison with comparable products from existing suppliers is also of interest. For this study, the quality of the diesel fraction was compared with diesel from various commercial sources.
The assignment was then to analyze these Pyrolyze fuels using the NEN-EN590 (NEN, 2017). The NEN-EN590 is a standard that describes the physical and quantitative properties that all diesel fuel for cars must meet within the European Union. The Pyrolyze diesel is compared with standard diesel B7 and V-Power.
The analyzes were performed by the employer of both students, Annemiek at Bureau Veritas and Remco at Veritas Petroleum Services (VPS). Here are the knowledge and equipment to analyze various parameters in-house.
The aim of the project is to determine the quality of the Pyrolyze diesel.
A main question has been formulated with a number of sub-questions.
1.1.1 Main question
Is the quality of Pyrolyze diesel comparable to diesel from existing diesel suppliers on the market?
1.1.2 Sub questions
- Which parameters are important to determine the quality of diesel?
- Which parameters are important for diesel that must fall within the environmental requirements?
- How does the Pyrolyze diesel compare to the diesel available on the market?
- Does the Pyrolyze diesel meet environmental requirements?
- Should the Pyrolysis of Waste Be Improved?
- What are the differences in the results of both labs?
Pyrolyze provided 3 types of samples:
- Unfiltered diesel from engine oil
- Unfiltered diesel from waste plastic (PS/PP/PE 1:1:1)
- Filtered diesel from waste plastic (PS/PP/PE 1:1:1)
The plastic waste is a mix of different plastics selected by Pyrolyze. Polystyrene (PS), polypropylene (PP) and polyethylene (PE) were mixed in the ratio of 1 to 1 to 1 and processed with the Pyrolysis system in the fractions.
The supplied volume per diesel type is approximately 500 mL. Due to the small volume, it was not possible to perform all analyzes from NEN-EN590. Table 2 provides an overview of analyzes performed in accordance with NEN-EN590. An overview of the performed analyzes has been made for each laboratory. The method used for each parameter and the technique with which the analysis is performed is shown for both lobatories. In the last columns of the table, similarities (green) and differences (red) in method between the laboratories are indicated with color. Orange means that 1 of the labs cannot perform this analysis.
Table 2. Overview of analyzes with associated techniques from both laboratories
The Pyrolyze products and reference material were analyzed at both laboratories for the parameters in table 3. This table shows the specifications that the diesel must meet per parameter according to NEN-EN590 (NEN, 2017). The measuring range per parameter of both laboratories is also shown. Green indicates whether the analysis range falls within the specified specifications. Orange indicates that the analysis cannot be performed at that laboratory.
Overview specifications according to NEN-EN590 and measuring range Bureau Veritas and VPS.
2.0 Material and Method
2.1 Samples and chemicals
The following samples were examined during this project:
- Unfiltered Pyrolyze diesel from engine oil
- Unfiltered Pyrolysis diesel from waste plastics (PS/PP/PE 1:1:1)
- Filtered Pyrolysis diesel from waste plastic (PS/PP/PE 1:1:1)
- Tinq diesel
- Shell diesel
- Shell v-power diesel
The Pyrolyze diesels were personally handed over by Peter Klaren during a short tour of the laboratory at Bureau Veritas.
The reference diesels were obtained at a gas station.
The following chemicals were used while analyzing the samples:
- Paraffin oil
Table 4 shows the analyzes performed with equipment used at both labs during the project.
Table 4. Equipment used during project
This chapter describes the different analysis methods of the analyzed parameters. Table 5 shows the parameters analyzed with the ISO/ASTM methods used at both labs.
Table 5 Overview methods of both laboratories
The results of this research are incorporated in the figures below. In these figures, the results of both laboratories are shown in boxes. A box with a dotted box is results from VPS and the boxes with a continuous box are results from Bureau Veritas. The figures show the specifications according to NEN_EN590 by means of a red line. When a result falls within the specifications, the box box is green, when a result falls outside the specifications, the box is red.
Texts within the figures are in English because the client wanted this better, so that they can be published directly on their internet site without further explanation.
Figure 1 shows the results of the water content. According to the NEN-EN590 specifications, the sample may contain a maximum of 200 mg/kg, which is indicated by a red line in the figure. The Pyrolyze samples and references fall within specifications according to NEN-EN590.
Figure 1. Water content results
Figure 2 shows the results of the viscosity measured at 40°C. According to the NEN-EN590 specifications, the viscosity must be between 2 and 4.45 mm2/s. The figure shows that all Pyrolyze samples and reference samples are within specification.
Figure 2. Viscosity results at 40°C
Figure 3 shows the results of the ash content. According to the NEN-EN590 specification, the sample may contain a maximum of 0.01% m/m ash after incineration. The figure shows that the pyrolysis samples and the reference samples are within the specification.
Figure 3. Ash content results
Figure 4 shows the manganese content. According to the NEN-EN590 specification, the sample may contain a maximum of 2 mg/L manganese. Manganese has only been analyzed at the Bureau Veritas lab. The results show that the diesel from waste motor oil contains a small amount of manganese. The other Pyrolyze diesels and reference diesels do not contain manganese. All samples are within specification.
Figure 4. Manganese content results
Figure 5 shows the results of the fatty acid methyl ester content. According to the NEN-EN590 specification, the sample may contain a maximum of 7% v/v. The figure shows that there is a difference between the Pyrolyze diesels and the reference diesels. The Pyrolyze diesels do not contain FAME and the reference diesels do contain FAME. It can also be seen that the results fall within the specifications of NEN-EN590.
Figure 5. Fatty acid methyl ester results
Figure 6 shows the results of the flash points. According to NEN-EN590 specification, the flash point must be at least 55°C. The figure shows that all reference diesels and the Pyrolyze diesel made of plastic are within specification. Bureau Veritas has not been able to determine a flash point for all Pyrolyze diesels.
The flash point of the Pyrolyze diesel from motor oil is shown in the figure with 0°C as the result. This is because the result is smaller than 40 (ISO2719).
Figure 6. Flash point results
Figure 7 shows the density results. According to NEN-EN590 spec
Figures 8 and 9 show the sulfur content results. Figure 8 shows the sulfur content analyzed with the WDXRF. NEN-EN590 specifications state that the sulfur content should not exceed 10 mg/kg. The figure shows that the Pyrolyze diesels and the reference diesel do not meet the specifications. The Pyrolyze diesel from motor oil has a high sulfur content compared to the diesel from plastic.
In addition to the WDXRF method, the samples were analyzed for sulfur on a Coulometer by Bureau Veritas. The results of this can be seen in figure 9. So no results of VPS are shown here. The same trend can be seen in figure 9 as in figure 8. The Pyrolyze diesel from motor oil has a high sulfur content compared to the diesel from plastic. That Shell v-power diesel is the only diesel that falls within the specifications analyzed with the coulometer technique.
Figure 8. Results sulfur content determined by VPS (XRF method)
Figure 9. Sulfur content results determined by Bureau veritas (coulometer method)
The raw data on which these figures are based are presented in Appendix 2. The Bureau Veritas certificates are also included in Appendix 1.
4.0 Discussion and Conclusion
The quality of the Pyrolyze diesel does not meet the requirements for a number of parameters. A number of parameters do not fall within the specifications of NEN-EN590. The Pyrolyze diesel also differs, on a number of parameters, from the standard diesels analyzed as a reference.
The Pyrolyze diesel does not fall within the NEN-EN590 specifications for the following parameters:
- Flashpoint, only for engine oil
The other analyzed parameters do fall within the specifications.
The Pyrolyze diesel differs from the standard diesels for the following parameters:
- flash point
The density results for the Pyrolyze diesel do not fall within the specifications of NEN-EN590. The results fall below the lower limit. The density of the Pyrolyze diesels are comparable. The reference diesels do fall within the specifications.
The FAME content in the Pyrolyze diesels is different from the FAME content of the reference diesels. The FAME content is a value that indicates how much biodiesel is in the sample that is mixed. The Pyrolyze diesels are made purely from plastic or motor oil and therefore contain no FAME. The lack of biodiesel in the Pyrolyze diesel can also cause the difference in density.
The results for the sulfur content of the Pyrolyze diesels are well above the upper limit of the specifications in NEN-EN590. Diesel from motor oil in particular has a high sulfur content. The increased sulfur content is due to the fact that motor oil contains sulfur compounds. These are partly responsible for the lubricity of the oil. The diesels made of plastic also fall outside the set specifications. This does not make sense, because plastic would not contain sulfur. It is possible that the system was contaminated before the plastic batch was pyrolyzed. The reference samples of VPS also fall outside the specifications of NEN-EN590. The concentrations are very low, which means that the equipment and calibration used may not be sufficient. The reference diesels analyzed at Bureau Veritas do fall within the specifications.
The flash point of the Pyrolyze plastic diesels is higher than the reference diesels. This may be due to the composition of the diesel. This can be looked at by comparing the previous research by Pyrolyze and the university of applied sciences with the results of this research.
The flash point of the Pyrolyze diesel from motor oil is too low to be determined with the available techniques. This means that the sample contains highly volatile components, which is why the flash point is so low.
Pyrolyze has taken a good first step in the process that is being developed. We can recommend the following for optimizing the process:
Analyze the other parameters listed in NEN-EN590. This gives a more comprehensive picture of the diesels and their characteristics. Especially the Cetane number, Micro Carbon Residue on 10% dist residue (MCR 10%) and distillation are parameters that say a lot about the diesel.
In the follow-up research, it could be decided to increase the FAME content. This means that a percentage of biodiesel can be added to the existing samples. This way it can be seen whether it has an influence on the diesels and its properties.
During this project, the diesels were tested against NEN-EN590. This is a very strict quality requirement. It is possible to make the diesel suitable for other markets where the requirements are less strict. An example is the use of diesel as fuel in the marine sector.
The diesel from motor oil has a number of parameters that are worrisome for its usability in the future. Especially the low flash point and the high sulfur are parameters that are important for the quality of the diesels. The process after the pyrolysis could be adapted, with the function of removing the light fractions from the diesel. This would improve the flash point. This could also affect the sulfur content. Further research could be done on this.
The plastic diesels, unfiltered and filtered, contain traces of sulphur. It is not clear where this comes from. There could still be contamination in the system prior to the pyrolysis, as a result of which there is sulfur in the diesel from plastic. This could be investigated in order to rule out that no sulfur comes out of the plastic. Investigating the origin of the sulfur is a good step towards usable diesels.
ASTM. (2016, Dec 01). ASTM D7111; Standard Test Method for Determination of Trace Elements in Middle Distillate Fuels by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). Retrieved from ASTM: https://www.astm.org/Standards/D7111.htm
ASTM. (2021, January 28). ASTM D6304; Standard Test Method for Determination of Water in Petroleum Products, Lubricating Oils, and Additives by Coulometric Karl Fischer Titration. Retrieved from ASTM: https://www.astm.org/search/fullsite-search.html?query=D6304&
ISO. (1996, June 01). ISO 12185; Crude petroleum and petroleum products — Determination of density — Oscillating U-tube method. Retrieved from ISO:iso.org/standard/21124.html
ISO. (2000, Nov 01). ISO 12927; Petroleum products — Determination of water — Coulometric Karl Fischer titration method. Retrieved from ISO: https://www.iso.org/standard/2730.html
ISO. (2001, October 01). ISO 6245; Petroleum products — Determination of ash. Retrieved from ISO: https://www.iso.org/standard/31156.html
ISO. (2003, July 01). ISO 8754; Petroleum products — Determination of sulfur content — Energy-dispersive X-ray fluorescence spectrometry. Retrieved from ISO: https://www.iso.org/standard/30062.html
ISO. (2016, June 01). ISO 2719; Determination of flash point — Pensky-Martens closed cup method. Retrieved from ISO: https://www.iso.org/standard/62263.html
ISO. (2018, August 01). ISO 20884; Petroleum products — Determination of sulfur content of automotive fuels — Wavelength-dispersive X-ray fluorescence spectrometry. Retrieved from ISO: https://www.iso.org/standard/74314.html
ISO. (2019, August 01). ISO 20846; Petroleum products — Determination of sulfur content of automotive fuels — Ultraviolet fluorescence method. Retrieved from ISO: https://www.iso.org/standard/74313.html
ISO. (2020, Sep 01). ISO 3104; Petroleum products — Transparent and opaque liquids — Determination of kinematic viscosity and calculation of dynamic viscosity. Retrieved from ISO: https://www.iso.org/standard/67965.html
NEN. (2017, Nov 01). NEN-EN590; Fuels for road vehicles – Diesel – Requirements and test methods. Retrieved from NEN: https://www.nen.nl/nen-en-590-2013-a1-2017-en-234751
NEN-EN. (2014, May 01). NEN-EN 14078; Liquid petroleum products – Determination of the content of methyl ester fatty acids (FAME) in middle distillate – Infrared spectrometry method. Retrieved from NEN-EN: https://www.nen.nl/nen-en-14078-2014-en-195412
NEN-EN. (2014, Nov 01). NEN-EN 16576; Fuels for road vehicles – Determination of manganese and iron content in diesel – Method by optical emission spectrometry with inductively coupled plasma (ICP OES). Retrieved from NEN-EN: https://www.nen.nl/nen-en-16576-2014-en-201413
Attachment 1: Certificates Bureau Veritas
Certificate Tinq diesel
Certificate Shell diesel
Certificate Shell V-Power
Certificate Unfiltered Pyrolyze diesel from engine oil
Certificate Unfiltered Pyrolyze diesel from mixed plastic
Certificate Filtered Pyrolyze diesel from mixes plastic