Mexico: Diesel Fuel
Background
Motor vehicle fuels in Mexico have been historically distributed by PEMEX (Petróleos Mexicanos), the state owned and operated oil company. President Enrique Peña Nieto proposed an energy reform in 2013 to allow independent companies to participate in the oil business supply chain, from exploration and production all the way downstream including the import, transportation, distribution, storage and sale of vehicle fuels. The energy reform was approved by congress and is being implemented. As a result of this energy reform the Energy Secretariat (SENER) and the Energy Regulatory Commission (CRE) have granted hundreds of permits to national and international companies to import, transport, store, distribute and sell fuels.
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Important steps in the evolution of Mexican fuel quality specifications include the following three standards:
- NOM-086—Before the energy reform, vehicle fuel quality was regulated by NOM-086-SEMARNAT-SENER-SCFI-2005 [2893].
- NOM-EM-005—As part of the energy reform, the responsibility of issuing regulations was transferred entirely to CRE. In late 2015, CRE issued a temporary standard, NOM-EM-005-CRE-2015 [3535], which would be valid for a maximum of 1 year. NOM-EM-005-CRE-2015 was based on NOM-086 with some additions to provide testing responsibilities for the supply chain players, as well as to incorporate new testing methods.
- NOM-016—After NOM-EM-005-CRE-2015 expired, CRE published NOM-016-CRE-2016 [3534].
2005 Diesel Fuel Specification (NOM-086)
Regulation NOM-086 defined two grades of diesel fuel:
- Automotive diesel (PEMEX) for use in on-road vehicles, and
- Marine and agricultural diesel.
The low sulfur automotive diesel grade (first introduced as Diesel Sin) replaced the earlier standard diesel of 5000 ppm (0.5%) sulfur. NOM-086 set the maximum automotive diesel fuel sulfur level at 500 ppm, followed by a phased-in reduction to 15 ppm: 2007.02—Northern frontier region that borders the USA; 2009.02—Metropolitan regions of Guadalajara (ZMG), Monterrey (ZMM) and the Valle de México (ZMVM); and 2009.09—Nationwide. However, the 2009 nationwide deadline was not met and on-road diesel with sulfur content above 15 ppm continued to be sold in parts of Mexico.
Diesel fuel for marine and agricultural applications is colored and has an upper sulfur limit of 5000 ppm.
The NOM-086 diesel specifications are listed in Table 1 [2893].
| Fuel Property | Unit | PEMEX Diesel | Marine & Ag Diesel | Std. Diesel† | Test* |
|---|---|---|---|---|---|
| Density @20°C | Report | Report | D1299 | ||
| Cetane Number, min | 48 | - | 451 | D613 | |
| Cetane Index, min | 48 | 40 | D976 | ||
| Sulfur, max | ppm | 500 152 | 5000 | 5000 | D4294, D5453 |
| Aromatics, max | % (v/v) | 30 | - | - | D1319 |
| HAPS | % (v/v) | Report | Report | ||
| Flash Point, min | °C | 45 | 60 | 41 | D93 |
| Ramsbottom Carbon 10%, max | % (wt.) | 0.25 | 0.25 | 0.25 | D524 |
| Ash, max | % (wt.) | 0.01 | 0.01 | 0.01 | D482 |
| Water & Sediment, max | % (v/v) | 0.05 | 0.05 | 0.05 | D2709 |
| Copper corrosion, 3h at 50°C | Class 1 | Class 2 | Class 2 | D130 | |
| Color, max | 2.5 | Purple | 2.5 | D1500 | |
| Lubricity, max | µm | 5203 | - | - | ISO 12156 |
| Viscosity @40°C | mm2/s | 1.9-4.1 | 1.9-4.1 | 1.9-4.1 | D445 |
| Cloud Point | °C | Report4 | Report | D2500 | |
| Pour Point | °C | Mar - Oct: ≤ 0 Nov - Feb: ≤ -5 | D97 | ||
| Distillation, max | °C | D86 | |||
| IBP | Report | - | - | ||
| 10% v/v rec. | 275 | Report | Report | ||
| 50% v/v rec. | Report | - | - | ||
| 90% v/v rec. | 345 | 350 | 350 | ||
| EP | Report | - | - | ||
|
† Historical on-road diesel grade, replaced by low/ultra low sulfur grades * ASTM, unless noted otherwise 1 - Cetane number or index 2 - Northern Frontier 02/2007; ZMVM, ZMG ZMM 02/2009; Nationally 09/2009 3 - Applies to imported diesel only. For domestically produced fuel, comes into effect with 15 ppm sulfur limit. 4 - Less or equal to minimum expected ambient temperature | |||||
2016 Diesel Fuel Specification (NOM-016)
NOM-016 defines two grades of diesel fuel [3534]:
- Automotive diesel for use in on-road vehicles, and
- Marine and agricultural diesel
The regulation specifies two different sulfur content limits for automotive diesel fuels: 15 ppm maximum for the larger metropolitan areas, the Mexico-US border and 11 transportation corridors, as well as for imported diesel; 500 ppm maximum for the rest of the country until December 31, 2018 after which the maximum sulfur content was to be 15 ppm for all of Mexico. However, this date was delayed numerous times due to difficulties supplying 15 ppm diesel fuel nationwide. These delays include resolutions issued by CRE in 2019 and 2023 that extended the deadline for PEMEX to comply with the nationwide ULSD requirement first to 01.2025 and then to 01.2026 respectively [6325][6326].
The 3 metropolitan zones defined in the Regulation are: Mexico City Valley (ZMVM), Guadalajara Metropolitan Area (ZMG), Monterrey Metropolitan Area (ZMM). The Northern Border Zone (ZFN) comprises the municipalities bordering with the USA in the states of Baja California (5), Sonora (22), Chihuahua (11), Coahuila (14), Nuevo Leon (6) and Tamaulipas (13). The 11 transportation corridors are formed by the highways that connect the largest industrial and Metropolitan areas:
- México City to Mexicali
- México City to Nuevo Laredo
- San Luis Potosí to Durango
- México City to Tampico
- México City to Merida
- Minatitlán to Oaxaca
- Highways to Guatemala
- México City to Lázaro Cárdenas
- México City to Acapulco
- México City to Matamoros
- México City to Monterrey
Marine and Agricultural diesel fuels have to be colored with purple dyes and have maximum allowable sulfur content of 500 ppm regardless of the region. There is no provision in the current regulation for sulfur content reduction as for on-road diesel. Other than these requirements, the specifications are almost identical.
Acknowledgement: This article based in part on information submitted by Armando Diaz of Sica Medicion.