Diesel Wholesale Grid Price
Magisterial District Zone
- Distillation (ASTM D86)
- Density at 20°C (ASTM D7042)
- Viscosity at 40°C (ASTM D7042)
- Flashpoint (ASTM D93)
- Total contamination (IP440)
- Water content (ASTM D6304)
- Sulphur content (ASTM D4294)
- Cetane index (ASTM D976)
- ISO 4406 Particle count (ASTM D7619)
- Distillation (ASTM D86)
- Colour and appearance (In-house)
- Density at 20°C (ASTM D974)
- Lead (Pb) content (In-house)
- Bacterial and fungal growth
- Total Acid Number (TAN)
- Illuminating Paraffin (IP) – Absence/Presence
- Illuminating Paraffin (IP) – Percentage
- Silver corrosion
- Copper corrosion
- Lubricity (HFRR)
- Biodiesel percentage
Density of petroleum diesel is 0.832 kg/L (6.943 lb/US gal), 11.6% more than ethanol-free petrol, which has a density of 0.745 kg/L (6.217 lb/US gal).
Significance of these tests
The flashpoint temperature of diesel is the minimum temperature at which the fuel will ignite on application of an ignition source. Flashpoint varies inversely with the fuel’s volatility. This helps identify petrol adulteration.
Viscosity is a measure of a fluids resistance to flow. It therefore affects injector lubrication and fuel atomisation. Fuels with low viscosity may not provide sufficient lubrication for the precision fit of fuel injection pumps or injector plungers, resulting in increased wear or leakage. High viscosity fuels on the other hand will increase gear-train, cam and follower wear on the fuel pump assembly due to the higher injection pressures. Diesel fuels with high viscosity also tend to form larger droplets on injection, causing poor combustion and increased smoke and emissions. Fuels that do not meet viscosity requirements lead to loss of performance.
Diesel with higher sulphur content produces more exhaust particulate emissions than diesel with a lower sulphur content which has major environmental implications. Local and international regulatory bodies have lowered the allowable percentage of sulphur in diesel to 0.05%, this may change in the near future to 0.005% as we strive to become more environmentally friendly. Most diesel vehicles function optimally with 0.005% sulphur content diesel. Using diesel with higher sulphur content can lead to failures of the emission control systems and/or corrosion of the cylinder liner and piston due to the formation of sulphuric acid.
Measures the temperature range over which a fuel turns to vapour. Volatility is one of the primary methods which distinguish various fuels from one as nother. They also give an indication of the fuels ability to start the engine, its power, fuel economy, emissions and deposit formation.
This is a measure of the specific gravity of the fuel. It essentially determines the energy content. The denser the fuel, the more power the engine can generate and vice versa.
Cetane Number (index)
The Cetane number is a measure of the ignition quality of the diesel. It represents the time delay between injection and ignition. If the Cetane number is too high, the fuel will ignite too close to the injector. This forms a fuel rich region whilst the rest of the chamber has a weak fuel to air ratio. Incomplete combustion and soot formation will be the result. Low Cetane fuels cause knock, difficult starting, rougher running and increased exhaust emissions.
Diesel samples are tested according to the ASTM D7619 test method, which covers sample preparation and ensures consistency and validity when measuring a particle count on a diesel sample. Although ISO 4406 is not sanctioned as a method for measuring fuel cleanliness in SANS 342, many customers and OEMs have cleanliness limits based on this method. The Worldwide Fuel Charter (WCF) publishes fuel quality recommendations based on the findings of the WCF committee to worldwide legislators, fuel users as well as producers and also makes recommendations, based on ISO 4406, for the target cleanliness of diesel.
Vehicle effect information
The presence of Sulphur in Diesel fuel can lead to the corrosion and wear of engine components on your diesel vehicle and this can have a significant effect on engine life. As the Sulphur level decreases, the relative engine life increases.
During combustion, the formation of Sulphur oxides and water vapour combine resulting in Sulphur acids (sulphuric and sulphurous acids). During combustion, nitrogen from the air is also oxidised, forming nitrogen oxides (NOx) which in turn become nitric and nitrous acids. These acids are extremely corrosive to engine components, so good quality engine oil fortified with appropriate levels of neutralising agents are necessary to protect the engine components from damage.
Exhaust Gas Recirculation (EGR), is now widely used in Light Duty and Passenger vehicles and to a lesser extent also in heavy duty engines. EGR effectively returns a portion of the exhaust gas back to the engine under part-load operating conditions.
Since NOx formation is extremely sensitive to temperature, by replacing some of the intake air with inert exhaust gas, the flame temperature can be reduced by a small amount and the NOx emissions can be reduced without seriously affecting the combustion efficiency.
The exhaust gas is usually cooled before returning it to the engine via the intake manifold and the small amount of sulfuric acid in the exhaust may condense, and this presents a risk of internal engine corrosion.
The lower the Sulphur level in the Diesel fuel, the lower the risk of internal engine corrosion in your vehicle.
Jet Fuel Testing
Modern jet aircraft require high quality fuel in order for the engines to provide optimum performance and safe flight.
Strict quality, handling, traceability and performance criteria must be met before the fuel can be used.
There are two types of aviation fuel now in use:
• Conventional Hydrocarbon Aviation turbine fuel (Avtur, Jet A, Jet A-1, JP8) refined direct from crude oil, also called jet fuel
• Newer innovative fuels such as the SASOL semi and fully synthetic fuels, now included in DefStan 91-91 and AFQRJOS specifications. These will soon be joined by a plethora of fuels based on innovative source materials such as gas to liquid fuels, Coal to liquid fuels, biomass to liquid fuels and even fuels from algal growth.
Classifications of Jet Fuel
Jet fuels can be traded under a number of standards:
• ASTM D 1655
• DefStan 91-91
• AFQRJOS , the joint checklist issued by JIG, the joint inspection group
Sampling, sample handling and sample preparation are all key elements on the successful testing of jet fuel. The standards developed under the auspices of CRS, CAFFI, IATA and JIG are all essential knowledge for the laboratory helping you control risk in the supply chain.
Derivative Hedging Instruments
The spotmarket, “bulk” market, is where physical product changes hands. It is the point where pricesfor physical gasoline, diesel, jet fuel andother commodities are assigned, with pricefluctuations often seen in-line with futures market moves.
Spot” refers to timing, such as “right now,” on-the-spot. “Spot” is also used to describe “near-future delivery” which is essentially, now. “Spot” would be the opposite of delayed, the “futures market”
OPEC—and only OPEC—controlled the global price of oil and gas. No transparency, no independent basis for pricing, just a closed-door system that, in other industries, would be anti-trust or, in less-veiled terms, “price-fixing.”
The “open market.” The only tried-and-true system that would establish trust in oil and gas prices was to allow the valuation of both to be subjected to the ebb and flow of the open market, or “exchange”—a place where suppliers and users could buy and sell petroleum products in public, unhidden, counting on open competition to stimulate pricing according to what the market will bear. That’s where “Spot Markets” come in. A Spot Market is not so much a place as it is a system where competitive prices are generated. It’s essentially the stock market for commodity oil. It’s where people all over the world, trade, broker, buy, and sell refined petroleum products.
Options and futures contracts are the most common derivatives. Such contracts can be used to hedge financial exposure. Hedgingrefers to the practice of reducing or fully eliminating the risk associated with holding a volatile asset.