Octane number requirement

Measuring Octane. Two different values need to be considered when discussing octane measurements. One is the knocking tendency of the fuel, called the fuel octane number. The other is the knocking tendency of the vehicle, called octane number requirement. 

The octane number requirement (ONR) of a car is the octane number which causes barely audible, ie, trace knock when driven by a trained rater. The Coordinating Research Council (CRC), a research organi2ation funded joindy by the American Petroleum Institute (API) and the American Automobile Manufacturers Association (AAMA), has defined test procedures for measuring ONR. Each car is driven under a set of light and heavy accelerations until the most sensitive driving mode is determined. Then a series of fuels is mn in the car until trace knock is determined. Each year, CRC members measure ONR of more than 100 cars and pubHsh the results. 

Octane blending debit/bonus, 72 411 Octane number, 18 665 Octane number requirement (ONR), 12 392, 393-394... 

The term octane number requirement (ONR) is used to describe the octane number of the fuel which will provide initial knock or trace knock, under highspeed and high-load conditions. Engines vary widely in their ONR. This is due to both engine design and environmental conditions. The following conditions can affect the ONR ... 

Figure 3. Effect of Tetraethyllead Content of Fuel and Test Mileage on Octane Number Requirement...

The increase in octane number required to replace lead can be achieved in a number of ways (Ref. 16), all of which increase the manufacturing costs some require substantial additional investment. At the current state of the art and prices the average cost of an octane-ton is about 1.8. The most attractive but limited octane enhancement is obtained by the use of octane boosting catalysts in the cat cracker. 

Despite all this the poisoning was real — and the only way out was a pretreatment of the feed and this was readily accomplished by a treating step prior to feeding the stock to the Platformer. Thus, we became quite aware of the effect of possible poisons, and as the octane number requirements became more severe we learned to install more sophisticated pretreating facilities. 

Table 3-9. Octane Number Required to Prevent Knockino...

Table 3-10. Approximate Octane Numbers Required to Satisfy 10, 50, AND 90 Per Cent of Nine 1953 Makes of Cars Operatino on Full-boiung-range Gasounes...

The octane number required by cars of even the same make ranges by at least 7 to 12 Research octane units (see Table 3 10). Although additional power can be developed by the use of high octane fuels in suitable engines, the extra power or mileage obtained by the use of high-octane-... 

In every part of the world, the same type of classification as above is found for fuels premium or regular, with or without lead. The octane numbers can be different from one country to another depending on the extent of development of their car populations and the capabilities of their local refining industries. The elimination of lead is becoming the rule wherever there are large automobile populations and severe anti-pollution requirements. Thus the United States, Japan and Canada no longer distribute leaded fuels. (... 

Figure 5.5 can be used to place the different product streams with respect to the objectives required for commercial octane numbers for Eurosuper and Superplus. It is clearly evident that the preparation of Superplus (RON 98, MON 88) will require careful screening of its components. 

When ethanoi is present, the risk of separation is much less than with methanol. Nevertheless, the ethanol should be relatively anhydrous (less than 3000 ppm water) moreover, if a fuel containing ethanol comes in contact with a water layer, a migration of ethanol toward the water is observed creating a fuel quality problem manifested by lower octane number and an environmental quality problem in that the water will need to be treated. Distribution of ethanol-based fuels requires extra precaution to ensure dryness in distribution systems. 

Refining alone can not, economically, provide a fuel to meet specifications the role of organic lead derivatives has long been to make up the difference between the octane number of the clear fuel and the octane required by legislation. 

Polymer Gasoline. Refinery trends tend to favor alkylation over polymerisation. Unlike the alkylation process, polymerisation does not require isobutane. The catalyst is usually phosphoric acid impregnated on kieselghur pellets. Polymerisation of butylenes is not an attractive alternative to alkylation unless isobutane is unavailable. The motor octane number of polymer gasoline is also low, and there is considerable shrinkage ia product volume. The only commercial unit to be built ia recent years is at Sasol ia South Africa. The commercial process was developed by UOP ia the 1940s (104). 

Conventional Hydrofining of diesel oils does not improve octane number because octane number improvement, like smoke point improvement in kerosenes, requires samration of aromatics. Higher pressures are needed to gain appreciable aromatics samration and cetane number improvement. 

TEL was not the only way to increase octane number. Those few companies who did not wish to do business with Jersey Standard, sought other means to produce a viable premium gasoline. TEL represented the most serious threat to the traditional gasoline product. It was cheap, vei y effective, and only 0.1 percent of TEL was required to increase the octane number 10 to 15 points. In contrast, between 50 to 100 times this concentration was required of alternative octane enhancers to achieve the same effect. 

The concentration of the ZSM-5 additive should be greater than 1% of the catalyst inventory to see a noticeable increase in the octane. An octane boost of one research octane number (RON) will typically require a 2% to 5% ZSM-5 additive in the inventory. It should be noted that the proper way of quoting percentage should be by ZSM-5 concentration rather than the total additive because the activity and attrition rate can vary from one supplier to another. There are new generations of ZSM-5 additives that have nearly twice the activity of the earlier additives. 

For long-chain alcohol esters it is interesting to see that the interfacial tension between a 0.01 wt % aqueous solution and octane or xylene has a minimum for ester sulfonates with a total 22 carbon atoms in the fatty acid chain and the ester chain [60]. The balance in length between the two chains has only a poor effect. Thus, a-sulfonated fatty acid esters with a total number of 22-26 carbon atoms in the molecule have excellent interfacial activities. To attain the same magnitude in the interfacial tension between linear alkylbenzenesulfonate (LAS) solution and octane, the required concentration of LAS is 0.1 wt %. This is 10 times the concentration needed for a-sulfonated fatty acid esters [60]. 

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