Asian Institute of Petroleum Studies, Inc

What is Cetane Number?
Here is something not commonly heard by motorists - Cetane Number. This is the counterpart of Octane in diesel. Someone asked me about this so I might as well post the explanation in FB for the info of my FB friends. What is Cetane Number?

In very lay terms, a Cetane Number is an imprecise indication on the time gap from fuel spray to ignition. The time gap is called the Ignition Delay (ID) . When the time gap is long, the fuel has low Cetane. If the time gap is short, the fuel has high Cetane .

A low Cetane number results in a long time gap and thus produces more diesel soots. If you have driven a diesel vehicle, you might have experienced a slow acceleration response when overtaking; or you experience sluggish power going uphill. This means your diesel fuel has a low Cetane number and it produces plenty of PM emissions. A high Cetane number has fast acceleration response because it is able to burn diesel fuel faster and more completely because of a shorter time-gap. Even old diesel engines can burn more of the fuel with a high cetane number than with a low cetane. The Cetane of automotive diesel is specified at 51. Coco Methyl Ester (CME) as cocobiodiesel has a Cetane number of 70. Diesel fuel with high cetane number has cleaner emissions!

Mar 3, 2019 B5 Cocobiodiesel substantially eliminates Diesel PM emission i.e. Black soots by > 80% and prevents carbon deposition in diesel engines. A simple cottonball test proves this very well. The black solid matter in the middle of the picture is the cottonball debris.

Mar. 2, 2019 TIME FOR B5 FOR FUEL ECONOMY

B5 means 5% blend of Coconut Methyl Ester (CME) in diesel fuel. This is otherwise known as B5 Cocobiodiesel. What we currently have is 2% CME blended in all diesel fuel sold in PH since 2009. Malaysia has 10% blend (B10) of Palm Methyl Ester (PME) while Indonesia has 30% blend (B30) of PME.

What does 5% CME do in diesel? CME contains a powerhouse of additive features inherent in the product that promotes complete and clean combustion of diesel fuel.

1) It has superb solvency that declogs fuel injectors and dissolves the high molecular weight component of diesel specially the microscopic asphaltenes that causes poor combustion and black soot emissions;

2) it has high lubricity that bonds a lubricious film in surfaces of all moving parts of the fuel injection system specially the fuel injector plunger;

3) it oxygenates the diesel fuel to boost combustion, and

4) it lowers the autoignition temperature of the diesel fuel to allow even old compression-deficient engines to attain better combustion and cleaner emission.

The Euro 4 diesel with 50 ppm sulfur has nothing to do with this. Euro 4 diesel is actually meaningless without the DOC, DPF units installed in the emission system of European vehicles. These DOC/DPF units function with a catalyst that are poisoned by sulfur. Therefore, it requires a low sulfur diesel to prevent poisoning of the DPF catalysts . This is the main purpose of Euro 4 diesel. Diesel vehicles in the Philippines do not have these DOC/DPF units but we have the power of CME that Europe does not have).

The result of all the features of CME apart from clean air is longer mileage. Various mileage test have been conducted with B5 vs B2. Under heavy traffic conditions in Metro Manila, the mileage of jeepneys reflected an average increase of 6% with B5 vs B2. Long distance “All Terrain” mileage test showed 10% mileage gain with B5 vs B2.

Asian Institute of Petroleum Studies, Inc AIPSI is a petroleum academe recognized by the Philippine DOE. It provides training, consultancy, and special studies in petroleum and biofuels.

SVO ALTERNATIVE TO BUNKER, Dec. 15, 2018
Thirteen (13) mos. from now, specifically in Jan 1, 2020, the supply-demand profile of High Sulfur Fuel Oil, HSFO, ( high sulfur bunker) and distililate fuel ( diesel) will substantially shift. This is the effectivity of IMO 2020 ruling requiring all marine vessels to run on fuel not exceeding 500 ppm sulfur (0.5%) a 3% reduction from current 3,500 ppm sulfur (3.5%). IMO stands for Int'l Maritime Organization.

Oil refineries cannot easily produce bunker with 500 ppm sulfur because it involves substantial additional capital investment in refinery process units. This will no longer make bunker price cheap and converting bunker to diesel might even be less costly.

Greater demand for diesel fuel with 500 ppm sulfur ( Euro 2 diesel) will follow in marine vessels and would naturally drive the diesel price to a very high side. Ship owners will logically seek for low priced alternative fuels perhaps with LNG, Methanol, or LPG. But the use of these alternatives involve engine modification requiring additional investment.

The most viable alternative to bunker fuel with minimal sulfur content with no engine modification that entails additional capital cost is a fuel which the Philippines and the Asean nations can be the major source of supply. It is the biomass alternative to bunker called SVO. This is acronym for Straight Vegetable Oil. Manufacturers of marine and gensets engines ( which are the same) such as Wartsila, Pielstick, MAN B&W, etc have long ago declared that 100% use of SVO is acceptable for use in their genset and marine engines as long as the SVO is processed (degummed). Best SVO is coconut oil owing to the fact that coconut oil has exactly the same carbon chain profile of diesel with very minimal unsaturates. Nevertheless, all biomass oil need to go through simple processing prior to their use as SVO fuel for Genset and Marine engines. There are several things in SVO that needs to be addressed.

1. Need to degum the vegetable oil if used as SVO.
2. Glycerine in vegetable oil with boiling temp of 290 C suppresses the volatility of medium carbon chain. This means SVO will volatilize and become combustible only at 290 C and beyond.
3. Plant oil with high amount of unsaturated carbon chain like soybean, rapeseed, palm, etc need to be doped with anti-oxidant additive.

Accordingly, a blend of 5% Coco Methyl Ester (CME) in any type of SVO will add important parameters on the SVO.

1. Provides superb solvency in the fuel that declogs the fuel injection system and naturally reduces the thick viscosity of plant oil.
2. Reduces the risk of filter clogging that may occur in SVO without CME.
2. Volatilizes early at 192 C instead of 290 C of glycerine to accelerate combustion.
3. With anti-oxidant, the oxidation stability of SVO is enhanced.

Rafael Diaz
Petroleum, Biofuels, and Biospecialties Consultant
Email. [email protected]