DOES HIGHER API LEVEL ALWAYS INDICATE
MUHAMMAD IQBAL, CHIEF EXECUTIVE OFFICER,
HAROON OILS LIMITED
Feb 6 - 12, 2012
Practically there is no prudence in blindly following the Standards without truly understanding their application conditionality / circumstances. But surprisingly some people tend to defend their errors as if they were defending their inheritance. It reminds me of Raycraft's famous saying as follows:
"To err is human and so is trying to avoid correcting it"
Such amazing state of the affairs may also be well described in the following Urdu verses:
Certainly, higher API Level does not always indicate the "Best" diesel engine lubricants due to their usage in high Sulfur Content Diesel Fuel (HSD) commonly available in the country. American Petroleum Institute (API) has developed Engine Oil Guide for Diesel Engines as well and categorically spelled out their Service Criteria. Accordingly, the performance and application of Diesel Engine Lubricants must be in line with the Quality of Diesel Fuel (specifically its High Sulfur Content) being used in the Compression Ignition combustion process.
Through this DAWN Supplement, I take the opportunity to reach out the masses of our country and beyond to get them updated on API Levels for Diesel Engine Lubricants and clarified which API Level is "Most Appropriate" for Pakistan keeping in view the quality of available diesel fuel.
Informally I also discussed this important issue with several of my friends in the industry that Higher API Levels such as: CJ-4, CI-4, CH-4, and CG-4 were not appropriate for Pakistan due to relatively higher Sulfur Content of HSD produced in the country. These Higher API Levels for Diesel Engine Lubricants would be applicable if and only if diesel fuel sulfur contents are lower (such as: 500 ppm or 0.05% or less for CJ-4 and 0.5% or less for CI-4, CH-4, and CG-4). Whereas, the Sulfur Content in HSD available in Pakistan tends to be in the range of 0.8 to 1% generally. According to International Standards, it is TOO HIGH as compared to Sulfur Content of 500 PPM (i.e., 0.05%) and 0.25% being readily used in most of the developed countries globally.
According to OCAC Statistics, around 6,927,069 Metric Tons of HSD was sold in Pakistan during the Financial Year 2010-11 (i.e., July 2010 to June 2011). Out of this total HSD volume, local refineries cumulatively produced around 3,223,210 Metric Tons and the rest accounts for the imports & inventories. Similarly, the production of Lube Base Oils during the same period cumulates to around 200,898 Metric Tons. Approximately, 65% of the overall finished lubricants (both locally blended as well as imported) get consumed in Transport & Power Generation Industries.
Let us have a close look at the following TABLE depicting API ENGINE OIL GUIDE for Diesel Engines:
ENGINE OIL GUIDE
DIESEL ENGINES CATEGORY STATUS SERVICE CJ-4 Current Introduced in 2006. For high-speed, four-stroke engines designed to meet 2007 model year on-highway exhaust emission standards. CJ-4 oils are compounded for use in all applications with diesel fuels ranging in sulfur content up to 500 ppm (0.05% by weight). However, use of these oils with greater than 15 ppm (0.0015% by weight) sulfur fuel may impact exhaust after treatment system durability and/or oil drain interval. CJ-4 oils are effective at sustaining emission control system durability where particulate filters and other advanced after treatment systems are used. Optimum protection is provided for control of catalyst poisoning, particulate filter blocking, engine wear, piston deposits, low- and high-temperature stability, soot handling properties, oxidative thickening, foaming, and viscosity loss due to shear. API CJ-4 oils exceed the performance criteria of API CI-4 with CI-4 PLUS, CI-4, CH-4, CG-4 and CF-4 and can effectively lubricate engines calling for those API Service Categories. When using CJ-4 oil with higher than 15 ppm sulfur fuel, consult the engine manufacturer for service interval. CI-4 Current Introduced in 2002. For high-speed, four-stroke engines designed to meet 2004 exhaust emission standards implemented in 2002. CI-4 oils are formulated to sustain engine durability where exhaust gas recirculation (EGR) is used and are intended for use with diesel fuels ranging in sulfur content up to 0.5% weight. Can be used in place of CD, CE, CF-4, CG-4, and CH-4 oils. Some CI-4 oils may also qualify for the CI-4 PLUS designation. CH-4 Current Introduced in 1998. For high-speed, four-stroke engines designed to meet 1998 exhaust emission standards. CH-4 oils are specifically compounded for use with diesel fuels ranging in sulfur content up to 0.5% weight. Can be used in place of CD, CE, CF-4, and CG-4 oils. CG-4 Current Introduced in 1995. For severe duty, high-speed, four-stroke engines using fuel with less than 0.5% weight sulfur. CG-4 oils are required for engines meeting 1994 emission standards. Can be used in place of CD, CE, and CF-4 oils. CF-4 Current Introduced in 1990. For high-speed, four-stroke, naturally aspirated and turbocharged engines. Can be used in place of CD and CE oils. CF-2 Current Introduced in 1994. For severe duty, two-stroke-cycle engines. Can be used in place of CD-II oils. CF Current Introduced in 1994. For off-road, indirect-injected and other diesel engines including those using fuel with over 0.5% weight sulfur. Can be used in place of CD oils. CE Obsolete Introduced in 1985. For high-speed, four-stroke, naturally aspirated and turbocharged engines. Can be used in place of CC and CD oils. CD-II Obsolete Introduced in 1985. For two-stroke cycle engines. CD Obsolete Introduced in 1955. For certain naturally aspirated and turbocharged engines. CC Obsolete CAUTION: Not suitable for use in diesel-powered engines built after 1990. CB Obsolete CAUTION: Not suitable for use in diesel-powered engines built after 1961. CA Obsolete CAUTION: Not suitable for use in diesel-powered engines built after 1959. Source: http://www.apicj-4.org/2009_ENGINE_OIL_GUIDE.pdf
API Level for Diesel Engine Lubricants starts with the Alphabet "C" that signifies to "Commercial" or "Compression Ignition". It is worth noting here that API Levels for Diesel Engine Lubricants from CA to CE stand Obsolete because they were developed for older models of engines from 1950 to 1985 respectively. But these types of oils, especially from CC to CE Levels, are still used in developing countries like Pakistan due to the continuity of usage of older engines.
According to the above API ENGINE OIL GUIDE, only API CF Level of Lubricants is highly appropriate for usage in places (like Pakistan) where the Sulfur Content of Diesel Fuel is more than 0.5% (mass basis). It is important to note that even API CF Level was introduced in 1994 (i.e., around 18 Years Ago!); but API Technical Team has not yet declared it Obsolete keeping in view the continuity of usage of High Sulfur Diesel Fuel in various developing parts of the world.
As per above API document, CG-4 Level lubricants must be used only when Sulfur Content of the available Diesel Fuel is fairly less than 0.5%. Similarly CH-4 and CI-4 Levels of Lubricants must be used only when the Sulfur Content of diesel fuel is up to 0.5%. However, usage of CJ-4 Level of Lubricants must be restricted to Sulfur Content of diesel up to 0.05% (or 500 ppm) or less.
Some people still stubbornly argue that they have increased TBN to 10 for their CG-4, CH-4 and/or CI-4 Levels of Diesel Lubricants to counter the corrosive effects of high diesel fuel Sulfur Content present in HSD available in Pakistan. Just imagine! Had it been so simple; then first of all API must have declared API CF (introduced in 1994) as Obsolete, and secondly they must not have categorically mentioned Sulfur Content of diesel fuel against each of API CG-4, CH-4, CI-4 and CJ-4 Levels respectively. Please refer API ENGINE OIL GUIDE presented above.
We must follow and apply International Standards after going through the micro-details pertaining to their applications / conditionality and after thoroughly understanding the ground realities prevalent in the actual circumstances. As far as Diesel Engine Lubricants are concerned, their Quality aspects are linked with the Quality of Diesel (i.e., its Sulfur Content) being used in the Internal Combustion Diesel Engines. There is no doubt that High API Level in general does signify High Quality lubricants, but here I do emphasize the importance of "Most Appropriate" solution in comparison to "The Best" one with respect to the ground reality of their application with High Sulfur Content of available HSD in Pakistan.
I am confident that this article will improve our pragmatic vision on the above significant technical aspects related to proper usage of Diesel Engine Lubricants and their corresponding API Levels.
Moreover, it would positively influence our mindset towards making the Most Appropriate decision in tune with our own circumstances & situation. I conclude my article with the following Japanese proverb to rekindle:
"Vision without action is a daydream. Action without vision is a nightmare!"