Motor octane

There are two standard procedures for determining the octane numbers Research or FI and the Motor or F2 methods. The corresponding numbers are designated as RON (Research Octane Number) and MON (Motor Octane Number) which have become the international standard. 

Regarding product characteristics, European specifications were established in 1992. They concern mainly the motor octane number (MON) that limits the olefin content and which should be higher than 89, and the vapor pressure, tied to the C3/C4 ratio which should be less than 1550 mbar at 40°C (ISO 4256). On the other hand, to ensure easy vehicle start-ups, a minimum vapor pressure for winter has been set which is different for each country and depends on climatic conditions. Four classes. A, B, C, and D, are thus defined in Europe with a minimum vapor pressure of 250 mbar, respectively, at -10°C (A), -5 C (B), 0°C (C) and -t-10°C (Z)). France has chosen class A. 

RON = research octane number MON = motor octane number. 

The CER engine is operated at two conditions to simulate typical on-road driving conditions. The less severe condition measures research octane number (RON) the more severe one measures motor octane number (MON). Table 1 summarizes the operating conditions for each test. 

Parameter Research octane number (ASTM D2699) Motor octane number (ASTM D2700)... 

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). 

Saturation of olefins other than reactive olefins usually is not desired. The added hydrogen is often expensive or useful elsewhere, and it does not provide any real improvement in product quality. Acmally, product quality may be reduced in the case of gasolines. Research octane number losses may be correlated with increasing olefin saturation. So in many cases, hydrodesulfurization conditions are selected with an eye toward minimizing olefin saturation over and above that needed for product quality improvement. There is one exception saturation of certain olefins shows substantial improvements in Motor octane number. This is true for iso- and n-pentenes and to a lesser extent for higher boiling isoolefins. The higher n-olefins show octane losses upon saturation. 

Volume of olefin/(volume of ionic liquid.hour). i-C = 2,2- and 2,3-dimethylbutanes, i-Cg = isooctanes, TMP trimethylpentanes, = hydrocarbon products with more than eight carbon atoms, Light ends = hydrocarbon products with fewer than eight carbon atoms, RON = research octane number, MON = motor octane number... 

Figure 3-7. Effects of soda on motor and research octanes motor octane vs. sodium oxide [11] research octane vs. sodium oxide [4].

Engelhard Corporation, Increasing Motor Octane by Catalytic Means Part 2, The Catalyst Report, EC6100P. 

Alkylation, where the olefins are reacted with isobutane to make a very desirable gasoline blending stock. Alkylate is an attractive blending component because it has no aromatics or sulfur, low vapor pressure, low end point, and high research and motor octane ratings,... 

Two octane numbers are routinely used to simulate engine performance the research octane number (RON) simulates gasoline performance under low severity ( 600 rpm and 120°F (49°C) air temperature), whereas the motor octane number (MON) reflects more severe conditions ( 900 rpm and 300°F (149°C) air temperature). At the pump, road octane, which is the average of RON and MON, is reported. 

Figure 6-6. Effects of unit cell size on research and motor octane [10].

Motor Octane Number (MON) is a quantitative measure of a fuel to knocking, simulating the fuel s performance under severe operating condition.s (at 900 rpm and at 300°F). 

The motor octane number jc7 was a function of the external isobutane-to-olefin ratio jc8 and the acid strength by weight percent x6 (for the same reactor temperatures and acid strengths as for the alkylate yield x4)... 

The last dependent variable is the F-4 performance number jc10, which was expressed as a linear function of the motor octane number jc7... 

Fig. 14 Hydrogenolysis on metal catalysts product from ring opening reactions of Cl ring contraction compounds and their corresponding research octane number and motor octane number. Adapted from ref. 100.

Table 12.2 Research and motor octane numbers (RON, MON) of C5-C7 alkane isomers.

IPE increment preparation error MON motor octane number... 

Now there are two octane scales, a research octane number (RON) and a motor octane number (MON). RON values reflect performance at 600 rpm, 125°F, and low speed. MON is a performance index of driving with 900 rpm, 300°F, and high speed. Before 1973 RON values were the ones usually... 

The demonstrated performance of ZSM-5 in over 35 cracking units is reviewed. The main features of ZSM-5 are its high activity and stability, favorable selectivity, metals tolerance and flexibility, particularly when used as an additive catalyst. ZSM-5 cracks and isomerizes low octane components in the naphtha produced by the faujasite cracking catalyst. As a result and olefins are produced and gasoline compositional changes occur which explain its increased research and motor octanes. A model was developed which predicts ZSM-5 performance in an FCC unit. 

Discussed is how this model calculates ZSM-5 activity, gasoline research and motor octane increases and catalyst management policies. Also discussed are ways to utilize ZSM-5 and how its use permits reoptimization of not only the FCC unit but the entire refinery. 

Table I lists some of the available results from twenty of these commercial applications. In all cases, ZSM-5 increased both Research and Motor Octane. The ZSM-5 content in the unit inventory for these applications ranged from 0.2 to 3 wt %. The variations in the octane response from a given concentration of ZSM-5 are due to variations in the base octane (octane without ZSM-5), gasoline cut point, catalyst makeup rate and regenerator temperature.

In addition to its octane enhancement ability described above, ZSM-5 also increases the feed to alkylation, methyl tertiary butyl ether (MTBE) and tertiary amyl methyl ether (TAME) units. Since the products from all these processes contain high Research and Motor Octane components, ZSM-5 provides the refiner additional flexibility in his downstream processing whenever the need exists to increase overall gasoline pool octane. In addition, the overall refinery can be rebalanced to take... 

To understand the reaction pathways, the yield shifts for the three examples illustrated in Table III were calculated on a fresh feed basis (Table V). These data show that the predominant reaction is the loss of C + paraffins and olefins. Approximately 2.5 wt 95 C + paraffins plus olefins were lost for a +1.5 Research Octane numoer increase. ZSM 5 is selective to cracking both single branched and linear paraffins, and single branched and linear olefins (9) which have very low Research and Motor Octanes, as illustrated below ... 

The products of the ZSM-5 reaction in the gasoline boiling range are mainly C -C single branched olefins which have high Resesirch and Motor Octane, as illustrated below ... 

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